An Apparatus and Method for Semi-Permeable Membrane Based Blood Filtration

Technical Field

This invention relates generally to apparatus’ and methods used far blood filtration such as hemofiltration, hemodiafiltration and hemodialysis as well as other blood processing means and interventions potentially including those related to blood and lymphatic cancers, organ failures, poisonings and drug overdoses.

Background Art

With kidney related diseases continuing to grow worldwide to near epidemic proportions, the need for a more accessible, cost effective and less lifestyle inhibiting means of blood filtration demands the type of inventive, near-term solutions that can quickly maximize and thus benefit from the elimination of unnecessary complexity, while simultaneously employing new and novel uses of existing materials, components, technologies and capabilities. Unfortunately, the high degree of complexity and, therefore, the costs associated with the prior art continue to escalate to the point where the financial burden on treatment funders is increasingly heavy and, in many parts of the world where funded treatment cannot be afforded and so is not offered, hundreds of thousands of people continue to suffer and die.

The goal of the apparatus and method of the present invention is to provide one such inventive near- term solution that does not depend on long-term research and future developments. In order to determine the best opportunities for improvement, a review of the prior art including in use, state-of-the art systems, components and capabilities was carried out and has provided examples falling into two general groups.

The first of these relates to prior art specifically associated with the treatment of kidney diseases and other forms of renal failure and typically involves semi-permeable membrane based hemodialysis, hemodiafiltration and hemofiltration methods. Systems already in use or under development and intended for more portable and/or wearable use were of particular interest, considering the urgency.

The second of these relates to prior art pressure-intensifying, hydraulic pump and motor based devices with energy recovery capability designed and used for the desalination of brackish water and seawater by reverse osmosis but described herein due to certain functional similarities to the apparatus and method of the present invention.

With particular regard to the prior art apparatus and methods employed specifically for blood filtration, especially those related to the hemodialysis, hemodiafiltration, hemofiltration, peritoneal dialysis and similar processes, no apparatus, methods or processes were found to offer the core operating principles of the present invention or its combination of simplicity and features, especially those related to pressure intensification, self-regulating pressure optimization and energy recovery. Prior art examples include: US 6,620,120 B2 Method for High Efficiency Hemofiltration, Donald W. Landry et. al.; US 6,623,441 B1 Blood- Purifying Apparatus and Artificial Kidney Using the Same, Kazuhiro Kahara, et. al.; US 6,955,655 B2 Hemofiltration System, Jeffrey H. Burbank et. al.; US 8,771,215 B2 Machine for Extracorporeal Treatment of Blood, Claudio Tonelli et. al.;

US 8,834,400 B2 Artificial Kidney, Franciscus Peter Houwen et. al.; US 5,284,470 Wearable, Portable, Light-Weight Artificial Kidney, Alex D. Beltz; US 3,951 ,570 Pumping Unit for Extracorporeal Hematic Circulation, In Particular in Artificial Kidneys, Gianfranco De Biaggi.

With regard to prior art apparatus and methods employed specifically for brackish water and seawater purification by reverse osmosis, several similarly acting examples provide proof-of-concept by association with regard to the present invention’s pressure intensification and energy recovery capabilities, although their designs are not similar and they incorporate a great deal more complexity. These include the commercially available Spectra Watermaker, as taught in the US 5,628,198 (Clark Permar) patent, the Schenker Watermaker, as taught in US 6,491 ,813 B2 (Riccardo Verde) patent, the KSB Salino and AQSEP / Danfoss reverse osmosis based seawater desalinators. Another key difference between these desalination focused apparatus and the present invention relates to their output. In each of the above cases, as well as for numerous other desalination systems, the permeate, that being potable water, is the desirable end product whereas, in the case of the present invention, either all or a significant portion of the permeate is an undesirable waste product, that typically being urine.

Disclosure of the Invention

This document includes material previously filed on 2018/09/27 and assigned Application No. 1018.662 by the Canadian Intellectual Property Office for which priority is being claimed.

The apparatus and method of the present invention offers distinct advantages and benefits over the prior art, as shall become evident in the following figures and descriptions. These include but are not limited to the following:

Basic embodiments may be constructed such that the only significant, physical restriction to blood flow is from the impellers of the apparatus’ pumps/motors. More specifically, they do not require the direct or indirect use of valves, regulators or other process control means in order for the apparatus and method to function. In effect, the only significant restriction to fluid flow other than from the pump and motor impellers is the unavoidable resistance, such as osmotic pressure, that is associated with fluid passing through the filtration media. While it is understood that the use of various flow monitoring, regulating and/or control and cleaning/flushing means could be employed in more fully featured embodiments, whether described herein or anticipated in others the more basic or core but nonetheless functional embodiments still allow for the removal of excess water and/or various undesirable and life-threatening solutes from the bloodstream without the necessity for the above mentioned additional features. This presents the opportunity for a dramatic reduction in both complexity and size to the degree that unlike the prior art, more highly portable apparatus including wearables are practical with varying degrees of internalization even being possible.

It presents the opportunity for a dramatic reduction in the costs associated with the more complex and expensive equipment and the dialysate and/or substitution fluids required for such prior art processes as hemodialysis, hemodiafiltration and high flux hemofiltration, thereby making life-saving and quality of life treatment options more widely accessible to the population at large and less of a burden on government funded and private insurance treatment programs.

The ability of the apparatus to minimize energy needs while safely intensifying hydrostatic pressure opens the door to employing a wider range as well as different combinations of semi-permeable membranes including both low and high flux types, thereby further expanding the use of blood filtration treatment opportunities. For example, it could be employed for the filtration of some cancerous and/or other targeted cells from the bloodstream and, by extension, from drainage from the lymphatic system, thereby reducing the need for more aggressive and damaging treatments such as chemotherapy and radiation.

To ensure clarity, it is also noted that these pump and motor types have a “stroke” but, unlike those with a reciprocating stroke aspect, the stroke of the rotary type has the advantage of being infinitely long in either direction of rotation. It is due to this unlimited stroke length feature that most of the embodiments of the present invention described herein employ rotary type pumps and motors as this eliminates the need for any type of stroke reversal means such as valves that can clog but also allows the more basic and core systems to function without the need for any other flow, pressure control or process control means - although it is noted that the incorporation of various non-core, optional sensing, control, safety, secondary processing and cleaning/flushing means are employed in the more fully featured embodiments that are also described herein or that may be anticipated by someone skilled in the art.

The apparatus and method of the present invention incorporates several key operating principles and features including but not limited to the following:

A first core operating principle of the apparatus and method of the present invention, relates to the existence of a continuing, intended and preferably stable volumetric differential in the amount of blood displaced by an upstream, positive displacement hydraulic pump and a downstream positive displacement hydraulic motor operating synchronously within the same series configured fluid circuit resulting in the development of hydrostatic pressure induced molecular transport across a cross-flow type semi-permeable membrane means. For example, in an embodiment where a higher output positive displacement pump is located upstream from a lower output positive displacement motor within a series circuit and where their operating outputs or speeds are synchronized, the volume of blood displaced and propelled forward by the larger output pump exceeds the volume of blood that can be displaced and propelled forward by the smaller output downstream motor. The resulting back pressure causes a rapid pressure increase within and limited to the pressure intensified fluid circuit located between the pump and motor. However, when a cross-flow, semi-permeable membrane based blood filtration means is incorporated into the pressure intensified fluid circuit between the pump and motor, the resulting hydrostatic pressure induced permeation of a volume of blood derived fluid through the membrane’s pores equal to the volumetric displacement differential between the pump and motor establishes a flow volume equilibrium that, in turn, limits further pressure increase. This represents one of the key means by which the present invention delivers significant advantages and benefits over the prior art, as shall become apparent.

A second core operating principle of the apparatus and method of the present invention relates to its controlled, meterable permeation capability. In other words, it provides for setting up a controlled permeation ratio between the amount of filtrate/permeate that is compelled to pass through the semi- permeable membrane to the amount of non-permeating retentate blood that flows back to the blood supply source such as a user/patient’s cardio-vascular system. This ratio can be preset in even the most basic of systems by simply determining in advance the volumetric displacement differential between the pumps/ motors and therefore, by extension, the permeation rate can also now be controlled because the blood pump module’s volumetric output can be controlled by changing the speed of the prime mover.

A third non-core but key operating principle employed in most of the embodiments of the apparatus and method of the present invention relates to its energy recovery capability, which is achieved when the potential energy in the pressurized blood located in the circuit between the larger displacement pump and smaller displacement motor is converted back to kinetic energy, for example through a shared driveshaft to the pump or, for that matter to the prime mover, thereby reducing the amount of energy the pump requires from its prime mover to function as intended and with the effect that the now depressurized blood is propelled forward by the motor at a pressure more safely matched to that which exists naturally in a user/ patient’s venous system.

A fourth non-core but key operating principle employed in most of the embodiments of the apparatus and method of the present invention relates to limiting/optimizing the amount of energy demanded of the prime mover for building pressure to only the amount needed to reach and maintain a hydrostatic pressure level where osmotic pressure is overcome and the filtration process begins and is sustained.

A key feature of the apparatus and method of the present invention relates to its ability to employ a plurality of semi-permeable membranes simultaneously, including different types with different pressure requirements, thereby expanding treatment opportunities and capabilities with little added complexity.

A further key feature of the apparatus and method of the present invention relates to its ability to route a selected volume of either the permeate portion or the filtered, non-permeate portion of the user-patient's blood back to their cardio-vascular system at various points during the blood filtration process, the latter being particularly beneficial when employed as a means of reducing or eliminating the normal requirement for the infusion of manufactured substitution fluids, as is the case with the process called hemofiltration.

A still further key feature of the apparatus and method of the present invention relates to its ability to eliminate the need for dialysate fluids while accomplishing the same or similar outcomes as hemodialysis. By comparison, current, state-of-the-art hemodialysis and hemodiafiltration processes require the additional use and frequent replacement of a dialysate solution in order to initiate and maintain the concentration gradient driven diffusion process they depends upon.

A still further key feature of the apparatus and method of the present invention relates to its ability to intensify the amount of pressure available from a given amount of input power, thereby extending the range of semi-permeable membranes that may be employed to accomplish desirable outcomes that would not normally be possible, especially with such simple apparatus’ as will be taught in the descriptions of Fig’s 1 and 2 that follow.

The following observations and comments are also provided for the benefit of improved clarity with regard to the Figures and their Descriptions in general:

Because cross-flow, semi-permeable membrane type blood filtration means are well known, in widespread use and well documented, they not themselves claimed to be novel aspects of the apparatus and method of the present invention and so are referred to herein only genetically with a detailed description of their actual construction and workings not deemed to be necessary beyond what is taught in the description of Fig’s 1 and 2.

While not a part of the core apparatus or essential for it’s operation, it is understood that for reasons of safety, additional pressure relief means may be incorporated even though the apparatus’ are designed to eliminate higher downstream pressure by way its energy recovery capability.

While the incoming stream of blood, in most cases, will arrive under low but positive pressure due to the pumping action of the user/patient’s heart, the blood pump module has the ability to draw in blood by creating a partial vacuum in situations where the user's heart is not able to provide the positive flow required, whether in whole or in part.

Preferably, the radial alignment of the pump and motor impellers will be matched or aligned in order to maintain the best possible pressure and flow matching between them.

While the volumetric displacement of the pumps and motors differs at a fixed ratio in certain basic and preferred embodiments due to a shared shaft or same acting means that enables energy recovery capability, it is understood that this ratio can vary depending on specifications applied during their design and assembly. However, it is fully anticipated that apparatus’ using controllers to to monitor and adjust the ratio based on changing needs will be employed in other embodiments, even though energy recovery capability and simplicity may be lost as a result in some cases.

Similarly, it is understood that while the pumps and motors or pump and motor sets are shown as being integrated into a single module in most embodiments described herein, they can also be employed as discrete units, sets or modules as long as the volumetric displacement differential between them and the same operating principles and method are maintained.

While the embodiments of the present invention taught in the descriptions that follow refer generally to the apparatus’ being directly connected to a user/patient’s cardio vascular system it is, nonetheless, understood that these apparatus may also be connected to blood supply sources other than a user/ patient’s cardio vascular system.

Because practices, regulations, medical practitioner preferences, available bridging appliances such as catheters, case-by-case requirements and the particular embodiment of the apparatus and method of the present invention can all vary, it is understood that when the apparatus is connected to a user/patient, the bridging medical appliances employed to connect to their cardio-vascular, waste elimination or other corporeal systems, whether directly or indirectly, are not themselves considered an aspect of the apparatus and method of the present invention.

In situations where a dialysate may be required for certain treatments, the apparatus of the present invention may also be employed in push/pull (PPHD) and pulsed push/pull (PPPHD) type hemod iafiltration systems including those employing two hemodiafilters in series and those employing a double chamber pump set, a pump/motor set or a a pump/hybrid motor-pump/motor set to alternate flow and/or flow pressures through a single hemodiafilter, noting that in the latter case, one is able to modify the opposing flow volumes by virtue of the apparatus’ volumetric displacement differential being determinable.

Brief Description of Drawings

Figure 1 provides a schematic view of a basic embodiment of the apparatus and method of the present invention wherein only its core aspects and components are shown.

Figure 2a provides a schematic view of a basic embodiment of the apparatus and method of the present invention similar to that of Fig. 1 but wherein the apparatus’ prime mover function is provided by an attached motor and wherein its location within a functioning hemofiltration system is shown.

Figure 2b provides a schematic view of a blood pump module similar to that employed in Fig. 2a but wherein the physical placement of the prime mover is different.

Figure 3 provides a schematic view of a basic embodiment of the apparatus and method of the present invention similar to those of Fig’s 2a and 2b but wherein the apparatus’ prime mover function is provided by the user/patient’s cardio-vascular system powered by the heart, rather than by an attached motor. Figure 4 provides a schematic view of an apparatus and method of the present invention similar to those of Fig's 2a and 2b but wherein two cross-flow type, semi-permeable membrane based filtration modules are incorporated in series configuration into the apparatus’ blood flow circuit.

Figure 5 provides a schematic view of an apparatus and method of the present invention similar to that of Fig. 4 but wherein a separate blood treatment process other than cross-flow type, semi-permeable membrane based filtration is incorporated into the non-permeate flow circuit.

Figure 6 provides a schematic view of a basic embodiment of the apparatus and method of the present invention similar to that of Fig, 2 but wherein an optional, synchronized auxiliary feed pump may be incorporated into the apparatus for such purposes as infusion.

Figure 7 provides a schematic view of an apparatus and method of the present invention similar to those of Fig’s 2a and 2b wherein the apparatus’ pumps/motors are driven independently by separate prime movers cooperating via a shared controller, thereby enabling adjustable ratio volumetric displacement differential capability.

Figure 8a provides a schematic view of the apparatus and method of the present invention similar to that described in Fig. 2 but wherein a temporary, bridging conduit connects certain other conduits by means of added conduit access ports for the purpose of enabling a system cleaning or backwash mode for use when the apparatus is operated in reverse rotation noting that this figure shows it in forward rotation production mode. Merge this info into 8b for new 8a then add #25 (Ceramic) or comparative #10 from Vane as 8c with old 8c moving to 8b.

Figure 8b provides a schematic view of the apparatus and method of the present invention similar to that described in Fig. 8a but wherein the apparatus is operated in counter-clockwise or reverse rotation backwash mode.

Figure 8c provides a schematic view of an embodiment of the apparatus and method of the present invention similar to that described in Fig. 8b but wherein the temporary, bridging conduit is replaced with a permanently integrated bridging conduit incorporating an inline one-way flow means.

Figure 9a provides a schematic view of the apparatus and method of the present invention similar to Fig. 4 but wherein three significant differences exist, these being the employment of (a) a blood pump module incorporating a plurality of cooperating pump and motor “sets” (b) a plurality of independently acting permeate flow splitting means, and (c) optional air/gas trap and backup pressure relief means.

Figure 9b provides a schematic view of a blood pump module similar to that described in Fig. 9a but wherein the individual pumps and motors are arranged in a different order but otherwise with all else being essentially equal to the system described in Fig. 9a.

Figure 10a provides a schematic view of the apparatus and method of the present invention similar to Fig. 9a but wherein the impellers of a plurality of pumps are fixedly attached to a first shared driveshaft driven by a first variable speed motor and the impellers of a plurality of motors are fixedly attached to a second shared driveshaft driven by a second variable speed motor with the effect that the cooperating pump and motor sets volumetric displacement differentials can be changed as needed.

Figure 10b provides a schematic view of a blood pump module similar to that described in Fig. 10a but wherein the individual pumps and motors are arranged in a different order but otherwise with all else being essentially equal to the system described in Fig. 10a.

Figure 10c provides a schematic view of a blood pump module equivalent to that described in Fig. 10b but wherein the pump and motor sets are not physically attached to each other.

Figure 11a provides a schematic view of the apparatus and method of the present invention combining various components and capabilities previously described with others that are new into a single, more fully featured embodiment wherein these components are capable of two-way wireless communication and are monitored and controlled by a suitable wireless control means.

Figure 11b provides a schematic view of a blood pump module similar to that described in Fig. 11a but wherein each pump/motor is driven by its own variable speed motor.

Figure 12a provides a schematic view of a preferred embodiment of the apparatus and method of the present invention that is simpler than but otherwise similar to that described in Fig. 9a. As with that of Fig. 9a, some key features of this particular embodiment include its ability to employ two semi-permeable membrane filters each with different hydrostatic pressure requirements and filtration capabilities and its ability to return a selectable volume of permeate, in this particular case being primarily excess water, to the user patient/s cardio-vascular system. Besides a pump component and motor component, this particular embodiment also incorporates a novel, dual function, hybrid pump/motor component that could be employed with various embodiments of the apparatus and method of the present invention including a multi-channel peristaltic version that is anticipated in early systems.

Figure 12b provides a chart displaying a breakdown of blood and permeate flows in terms of volumetric units (vu) and associated hydrostatic pressures within each of the pumps, motors and fluid carrying conduits described in Fig. 12a. It is provided for the benefit of clarity as a summary of the information available within the description of Fig. 12a.

Figure 12c provides a schematic view of an adjustable version of the internally branched "Y" inserts taught in the description of Fig. 12a.

Figure 12d provides a schematic view of a blood pump module similar to that employed in the apparatus of Fig. 12a but wherein the novel, dual function, hybrid pump/motor is not employed and so is replaced with a pump, a motor and a connecting conduit.

Figure 13 provides a schematic view of an embodiment of the apparatus and method of the present invention similar to that described in Fig. 2 but wherein the blood pump module also incorporates an isolation barrier protected pneumatic motor employed as the priority prime mover but backed up by an electric motor with an over-running clutch.

Figure 14 and it’s associated identification numbers 107-122 have been removed.

Figure 15 provides a schematic view of an embodiment of the apparatus and method of the present invention similar to that of Fig. 13 but wherein a hydraulic rather than a pneumatic motor is employed as the priority prime mover and a magnetic drive coupling is employed to further isolate the hydraulic fluid from the blood flow circuit for safety reasons.

Figure 16 and it’s associated identification numbers 129-135 have been removed.

Figure 17 provides a schematic view of an embodiment of the blood pump module similar to that described in Fig. 15 but wherein an additional pump has been incorporated for the purpose of moving urine permeate under a positive pressure.

Figure 18 provides a conceptual, three dimensional view of a portable, user-worn belt pack style embodiment of the present invention whose purpose is to provide various advantages and benefits when compared to prior art processes.

Figure 19 provides a schematic view of an embodiment of a blood pump module combining the previously described features and capabilities of the blood pump modules of Fig’s 12a, 13 and 15 and, which could be incorporated into various embodiments of the present invention including that of Fig. 18.

Figure 20 provides a schematic side view of a gerotor type, positive displacement pump/motor, it being one of numerous types that may be employed in the apparatus and method of the present invention.

Figure 21 provides a schematic end view of the gerotor type pump/motor, described in Fig. 20, it being provided for the purposes of improving visualization and clarity.

Figure 22a provides a view of the blood filtration system taught in Fig. 12a but wherein the generic representation of the blood pump module is now shown with a more detailed view of the blood pump module which, in this particular example is a peristaltic type.

Figures 22b-h provide further examples of blood pump module types that may be employed interchangeably in the blood filtration system taught in the descriptions of Fig’s 12a and 22a.

Figure 23 provides a view of the blood filtration system taught in Fig. 2a and 2b but wherein the generic representation of the blood pump module is now shown with a more detailed view of the blood pump module which, in this example is a valveless, rotary-reciprocating metering type.

Best Mode(s) for Carrying Out the Invention (Detailed Description of the Figures)

Referring now to Fig. 1 , a schematic representation of a basic embodiment of the apparatus and method of the present invention incorporating only it’s core components and features is shown and described. These include a blood pump module 1, a cross-flow type, semi-permeable membrane based filtration module, hereafter referred to as the semi-permeable membrane filter 2 and several unrestricted fluid conduits 12, 13, 14, 15 and 16 that deliver a flow of blood 17 to and from the blood pump module 1, the semi-permeable membrane filter 2 and a user/patient’s cardio-vascular system and waste elimination system. The blood pump module 1 incorporates both energy recovery and self-regulating pressure limiting/ optimization capability when operating within a series circuit that also comprises the semi-permeable membrane filter 2 and the conduits 13 and 14,

In this embodiment, the blood pump module 1 is comprised primarily of a positive displacement pump 3 with a nominal, fixed displacement of 1.0 volumetric units (VU) and shown here with an unrestricted intake port 4 and an unrestricted discharge port 5; a positive displacement motor 6 with a nominal, fixed displacement of 0.9 volumetric units (VU) and shown here with an unrestricted intake port 7 and an unrestricted discharge port 8. The ratio of the volumetric displacement differential between the pump 3 and motor 6 is, therefore, also nominal and, in application, may be less or more but must, nonetheless, exist. Also, the larger volumetric displacement pump 3 in all cases must be located upstream from the smaller volumetric displacement motor 6 for the apparatus and method of the present invention to function as intended. In this embodiment, the volumetric displacement differential between the pump and motor is at a fixed ratio because the impellers of the pump 3 and the motor 6 are fixedly attached to a shared driveshaft 9. The semi-permeable membrane filter 2 is comprised primarily of a suitably fitted vessel 10 capable of maintaining pressure suitable to the intended application, in this case being hemofiltration, and within it, a replaceable, semi-permeable membrane element 11, also suitable for a preferred or intended application, such as hemofiltration.

Hemofiltration is a process typically used for the separation and removal of excess water and undesirable solutes such as but not limited to urea, creatinine and potassium from the blood and, due to ongoing developments in semi-permeable membrane technology, potentially also for the separation and removal of other undesirable solutes from the bloodstream and by extension, from drainage into the bloodstream from the lymphatic system. The conduits 12, 13, 14 and 15 allow for the flow of blood 17 between the blood pump module 1 and the semi-permeable membrane filter 2 as well as any other components or medical appliances employed to connect the apparatus to the user/patient’s cardio-vascular system. The flow of a fluid/solution called permeate 18 comprised of the excess water and undesirable solutes mentioned above is separated into a second, usually smaller stream by passing through the semi- permeable membrane element 11, and then out of the semi-permeable membrane filter 2 via the conduit 16 for elimination from the user/patient’s body. The blood pump module 1 is, in this particular embodiment, driven by a suitable prime mover means 19, which is shown here as being connectable to the shared driveshaft 9, although it is understood that other prime mover means may be employed in different embodiments.

It is noted that here in Fig. 1, as in certain subsequent drawings, the pump and motorjmpellers are not shown or described because the positive displacement pump and motor types employed in the apparatus and method of the present invention can vary. However, a detailed description of one type is, nonetheless, provided in Fig’s 10 and 11.

A description of how the apparatus and method of the present invention functions in cooperation with the user/patient's cardio-vascular and waste disposal systems by means of an integrated, continuous circuit will now be detailed in the description of Fig. 2.

Referring now to Fig. 2a, a schematic representation of the apparatus and method of the present invention equivalent to that described in Fig. 1 is shown in the context of tracking the blood and waste fluid flows within a basic blood filtration system.

Blood 17 flows continuously out of the user/patient’s cardio-vascular system 20 and on through the apparatus of the present invention and, with the exception of the above mentioned excess water and undesirable solutes that pass through the semi-permeable membrane element 11 as permeate 18 as waste to be disposed of, then flows back into the user/patient’s cardio-vascular system 20 to repeat and continue this cycle for the duration of a prescribed treatment session.

More specifically, the blood 17 exits the user/patient’s cardio-vascular system 20, via a suitable, bridging medical appliance 21 such as a catheter, fistula or other similar means normally selected by a qualified medical practitioner and then flows via the conduit 12 into the pump 3 through its intake port 4 and back out of its discharge port 5 from where it continues on through the conduit 13 into the semi-permeable membrane filter 2 where it becomes separated into the two streams.

The first of these streams is a typically larger volume of blood 17 which flows across but not through the semi-permeable membrane element 11 within the semi-permeable membrane filter 2 and then exits via the conduit 14 from where it flows into the motor 6 through its intake port 7 and back out of its discharge port 8 from where it then continues on through the conduit 15 to be returned into the user/patient’s cardio-vascular system 20, either via the same bridging medical appliance 21 that it left by but, if not, then via a similarly acting one depending on choices made by a medical practitioner.

The second stream is comprised of a typically smaller volume of permeate 18 that is compelled, due to the volumetric displacement differential and its associated hydrostatic pressure increase within the portion of the series circuit located between the pump 3 and motor 6 and incorporating the semi-permeable membrane filter 2, to flow through the pores of the semi-permeable membrane element 11 within the the semi-permeable membrane filter 2 from where it exits and flows via the conduit 16 into either the user/ patient’s bladder 22, a urostomy bag 23 or a combination of both of these via a suitable, bridging medical appliance 24 as shown in this particular embodiment but not in all, as shall be seen in other embodiments described herein. The prime mover 19 (Fig. 1) is defined here in Fig. 2 as a motor 25 whose body or frame is fixedly attached to the blood pump module 1 and whose rotating drive means is connected to the shared driveshaft 9 of the blood pump module 1 by suitable means such as a coupling.

With the flow of the blood 17 and permeate 18 within the above blood filtration system now described, the reader’s attention is drawn to the function and operating principles of the apparatus and method of the present invention with particular attention being paid to the blood pump module 1, it being the primary and most novel component of the apparatus and method. We begin by recalling that the volumetric displacement of the downstream located motor 6 is nominally less than that of the upstream located pump 3 that the blood is propelled downstream by. Because both the pump 3 and motor 6 are of the positive displacement type, meaning that they are effectively sealed against the forward or backward leakage or slip of blood past their impellers and because their impellers are fixedly attached to the shared shaft 9, the motor 6 can not rotate faster than the pump 3, which would be needed in order to match their volumetric outputs within the fluid circuit between them. This means that the pump 3 pushes more blood downstream to the motor 6 than it can circulate. In effect, the motor 6 functions as a flow resistor resulting in a resistance based back pressure rather than only for propelling the fluid forward.

With that in mind and as has been well established by the previously mentioned and commercially available reciprocating type, reverse osmosis based seawater desalinators such as the Spectra Watermaker, as taught in the US 5,628,198 (Clark Permar) patent and the Schenker Watermaker, as taught in US 6,491,813 B2 (Riccardo Verde) patent, as well as the commercially available KSB Salino and AQSEP/Danfoss reverse osmosis based seawater desalinators, such a volumetric displacement differential within a series circuit located between two positive displacement hydraulic pumps/motors results in a rapid pressure rise within the circuit that continues until either (a) the incoming excess fluid from the larger volumetric displacement pump can find a path of escape (b) the pump stalls because the back pressure upon it overcomes the capability of its prime mover, or (c) there is a rupture or similar failure within the fluid circuit located between the two pumps or within a pump itself. As with those reverse osmosis based desalinators, the apparatus and method of the present invention relies upon (a) where the incoming excess fluid finds a path of escape as the means of matching the volume of fluid circulated by the pump and motor, thereby establishing a condition where neither continued pressure rise nor detrimental conditions such as pump cavitation occur.

Because the semi-permeable membrane filter 2 is located within the closed hydraulic circuit between the pump 3 and the motor 6, this path of escape occurs the moment that the fluid pressure within the semi- permeable membrane filter 2 reaches the point where osmotic pressure as well as any other incidental forms of resistance are overcome by the intensified hydrostatic pressure such that the conditions for convection are reached and the flow of fluid through the pores of the semi-permeable membrane begins, with only the amount of pressure needed to initiate and maintain the required hydrostatic pressure, while also adapting to pressure requirement variations over time, all without the need for any form of external input, control or other complexity.

More specifically, a solution comprising excess water and a variable range of dissolved, undesirable solutes equal in volume to the volumetric displacement differential between the pump 3 and the motor 6 is compelled under intensified pressure to pass through the pores of the semi-permeable membrane element 11 within the semi-permeable membrane filter 2 as permeate 18, the passage being represented here by the series of smaller arrows seen within the semi-permeable membrane filter 2. As previously described, the permeate 18, in this particular embodiment, flows via the conduit 16 into either the user/patient’s bladder 22 and/or urostomy bag 23 via a suitable, bridging medical appliance 24.

To clarify, it is the volumetric displacement differential and its resultant hydrostatic pressure intensification that compel the excess water and smaller sized solutes to permeate the semi-permeable membrane element 11 and thus become separated from the larger sized blood cells and plasma components that flow across but do not permeate or pass through the pores of the semi-permeable membrane element 11 and so remain in the larger, non-permeating retentate stream of blood 17.

The typically larger volume of blood 17 that is not compelled to pass through the the semi-permeable membrane element 11 flows out of the semi-permeable membrane filter 2, still under increased pressure (representing potential energy) through the conduit 14 into the intake port 7 of the motor 6, whereupon it encounters and has its flow finally obstructed, as previously described, by the impeller(s) of the motor 6.

Referring again to that taught in the US 5,628,198 (Clark Permar) and US 6,491,813 B2 (Riccardo Verde) patents and employed by the KSB Salino and AQSEP/Danfoss desalinators, so too in the apparatus and method of the present invention is the potential energy stored in the pressurized fluid (blood) that would normally be taken up or dissipated by rotating the motor 6 faster than the pump 3 in order to absorb the displacement differential cannot occur because both the pump 3 and motor 6 impeller(s) are fixedly attached to the shared driveshaft 9 with the result that this pressure based potential energy is instead transferred back through the shared, rotating driveshaft 9 to the pump 3 impeller(s) as kinetic energy, thereby greatly reducing the amount of energy required for the prime mover motor 25 itself to drive the system. With that energy expended, the now depressurized stream of blood 17 flows out of the discharge port 8 and is returned at a pressure more safely matched to that which exists naturally in the venous portion of the user/patient’s cardio-vascular system 20 via the conduit 15 and the bridging medical appliance 21 to the user/patient’s cardio-vascular system 20 to repeat the cycle for the duration of the prescribed treatment time. Referring now to Fig. 2b, a schematic view of a blood pump module equivalent to that of Fig. 2a is provided wherein the only difference is in the physical placement of the motor 25 now seen to be located between the pump 3 and the motor 6, each of these having their impellers rotated by the shared driveshaft 9. In that regard, it is understood that the impellers of the pump 3 and motor 6 are fixedly attached to the shared driveshaft 9 just as before and cooperate in the same way as was taught in Fig. 2a.

Referring now to Fig. 3, a schematic representation of the apparatus and method of the present invention is provided wherein the only difference from that described in Fig’s 1 and 2 is that the apparatus’ prime mover function is provided by the user/patient’s cardio-vascular system 20 powered by the heart 26, rather than by an attached motor 25.

More specifically, the user/patient’s heart 26 produces a flow of pressurized blood 17, a portion of which flows from the user/patient’s cardio-vascular system 20 via a suitable bridging medical appliance 21 and, as was previously taught in the description of Fig. 2, flows via the conduit 12 into the intake port 4 of the pump 3 of the blood pump module 1 and onward to complete that cycle taught in the description of Fig. 2. It is noted that in this case the motor 6 functions similarly to a hydraulic motor in that it is rotated by the force of pressurized blood 17 acting upon its impeller(s) but, nonetheless, it is understood that the pump 3 and motor 6 are fixedly attached to the shared driveshaft 9 just as before and cooperate in the same way as taught in the preceding descriptions.

However, it is noted that a similar embodiment would retain the external motor 25 or an equivalent prime mover means to serve as a backup employed to provide power on a manually or automatically activated on-call basis and wherein the provided power could be on a variable assist basis using the analogy of an e- bike that offers adjustable, variable assist power.

Referring now to Fig. 4, a schematic representation of the apparatus and method of the present invention is provided wherein the only difference from that described in Fig. 2 involves the insertion of a second semi-permeable membrane filter 27 placed in series configuration immediately downstream from the first semi-permeable membrane filter 2.

Here, as was the case in Fig. 2, the permeate 18 flows from the first semi-permeable membrane filter 2 through the conduit 16 into the bladder 22 and/or urostomy bag 23. However, in this case, the retentate stream of blood 17 exiting the first semi-permeable membrane filter 2 now flows through a conduit 28 into the second semi-permeable membrane filter 27 and again separated into two streams.

Again, as was the case in Fig. 2, the first of these streams is a typically larger volume of blood 17 which flows across but not through the membrane(s) within the the semi-permeable membrane filter 27 and then exits via the conduit 14 and flows into the motor 6 through its intake port 7 and back out of its discharge port 8 from where it continues on through the conduit 15 to be returned into the user/patient’s cardio- vascular system 20, typically via the same bridging medical appliance 21 it left by or via a similarly acting one, depending on choices made by the medical practitioner.

Yet again, as was tire case in Fig. 2, the second stream is comprised of a typically smaller volume of permeate 29, which is again compelled to move through the pores of the membrane(s) within the semi- permeable membrane filter 27 from where it then exits and flows via the conduit 30 into the conduit 16, there combining with the permeate 18 from the first semi-permeable membrane filter 2 to enter the user/ patients bladder 22 and/or urostomy bag 23 via the bridging medical appliance 24.

Having two or more semi-permeable membrane filters makes it possible to employ more than one type of semi-permeable membrane element in order to take advantage of their different features and capabilities. For example, the first module might incorporate a type of membrane typically used for treating a given illness such as kidney disease whereas the second might incorporate a new, leading edge and potentially more expensive membrane type designed to remove a different, undesirable molecule, cell or solute but which would become more quickly clogged without the initial filtering by the first membrane, thereby extending the life of the more expensive membrane and reducing treatment costs. Research and development relating to emerging new membrane materials such as graphene, graphene oxide and related compounds, as well as membrane types and coatings that exhibit special properties such as the selective attraction of ions or show promise, not only for established applications but potentially also for non- aggressive cancer cell removal, for example. Other advantages such as, but not limited to, increased capacity, staged/altemating cartridge exchange and extended cartridge replacement cycle times are also envisioned. The apparatus and method of the present invention are designed to take advantage of these developments. It is noted, however, that this particular setup would not be well suited for the use of membranes with different pressure requirements as permeation would tend to occur only or mostly within whichever semi-permeable membrane filter required the lowest pressure unless, for example, an optional pressure adjusting means such as a regulator, reducing valve or similar device was incorporated into the conduit 28 between the semi-permeable membrane filters 2 and 27. However, even without that non-core option, this potential limitation is addressed in other embodiments of the present invention.

Referring now to Fig. 5, a schematic representation of the apparatus and method of the present invention is provided wherein the only difference from that described in Fig. 4 involves insertion of a separate blood treatment means 31 other than by semi-permeable membrane filtration such as apheresis into the permeate flow circuit of the apparatus of the present invention. More specifically, upon exiting the second semi-permeable membrane filter 27, the permeate 29 flows through a conduit 32 into the additional blood treatment means 31 and, upon completion of that process, flows through any one of a variety of possible flow splitting means 33 that diverts a pre-determined percentage from 0 to 100 percent of the blood 17 exiting the additional blood treatment means 31 either (a) via a conduit 34 into the bladder 22 and / or urostomy bag 23 or (b) through a conduit 35 that feeds into the conduit 15 leading back into the user / patient’s cardio-vascular system 20. in order to maintain the intensified pressure within the series circuit a conduit 36 carries the blood 17 leaving the additional blood treatment means 31 back to the intake port 7 of the motor 6.

One example of how this setup might be used involves employing the first semi-permeable membrane filter 2 to remove the excess water and smallest undesirable solutes from the blood 17 by choosing a semi- permeable membrane filter 2 designed for that purpose. The blood 17 would then be subjected to a second filtering process using a differently specified semi-permeable membrane filter 26 that could, for example, be designed to remove certain larger sized solutes such as specific cells from the blood 17 for processing by the added blood treatment, reconstituting or monitoring means 34 before being selectively routed into the bladder 22 and/or urostomy bag 23, back into the user/patient’s cardio-vascular system 20 or some combination of both by the flow splitting means 36 working in cooperation with the blood treatment, reconstituting or monitoring means 34. It is noted that the same feature/capability could be applied to a permeate stream if there was a need.

Referring now to Fig. 6, a schematic view of a basic embodiment of the apparatus and method of the present invention similar to that of Fig. 2 is seen wherein an auxiliary feed pump 37 is incorporated into the blood pump module 1. In this embodiment, the auxiliary feed pump 37 is a rotary centrifugal type and is driven, like the pump 3 and motor 6, by the shared driveshaft 9 and is fixedly attached to the blood pump module 1 and the prime mover 25. Nonetheless, the core operating principles of the apparatus and method of the present invention remain the same.

Atypical use of the auxiliary feed pump 37 would be to infuse one or more constituents 38 into the filtered blood 17 before it is returned to the user/patient’s cardio-vascular system 20. More specifically, the constituents 38 are fed from an external source by a conduit 39 into the auxiliary feed pump 37 that in turn, propels them through a conduit 40 into the conduit 15 to be returned to the user/patient’s cardio-vascular system 20.

It is important to note that any pump used for such purposes as infusion, should not be capable of causing a significant spike in pressure within the cardio-vascular system, as would normally be the case with a positive displacement pump. Therefore, the auxiliary feed pump 37 used in this embodiment is understood to be either a centrifugal type pump designed to limit any potential pressure increase or otherwise, it would be so limited by some other dependable means. It is also noted that the auxiliary feed pump 37 could be incorporated in some other manner and location where it would be powered by its own prime mover and, as such, its flow rate and influence on blood pressure would be controlled separately as it would not be directly attached to the shared driveshaft 9. These constituents 38 would normally be determined and prescribed by a medical practitioner and connected to the in-feed conduit 39 either by or according to their instruction.

Referring now to Fig. 7, a schematic representation of the apparatus and method of the present invention is provided wherein the blood pump module 1 (Fig. 2) is replaced with a blood pump module 41 wherein the pump 3 and the motor 6 do not share a common driveshaft means and so can be rotated at different speeds but are otherwise essentially unchanged from those seen in Fig. 2. Instead, a driveshaft 42 rotates the impellers of the pump 3 which is fixedly attached to a second prime mover 43 and a driveshaft 44 rotates the impellers of the motor 6 which is fixedly attached to the first prime mover 25.

Because of the need to maintain a volumetric displacement differential between the pump 3 and the motor 6, a suitable control means such as a programmable controller 45 is in communication with both the pump 3 and the motor 6, here via cables 46 and 47 but may also be implemented by equivalent means such as wirelessly. Having the control means integrated into the prime mover housings is also anticipated. A feature of this apparatus lies in it’s ability to adjust volumetric displacement differential ratios easily including in real time.

It is noted that in embodiments without a shared driveshaft or equivalent means, the potential energy found in that part of circuit between the pump 3 and motor 6 due to intensified pressure is instead transferred back to the motor 25, which in this configuration functions like a torque brake. It is also noted that where the pump 3 and motor 6 are not physically hard-linked, there is some risk of suffering a loss of pump to motor synchronization, such as could occur with stepper type motors losing steps. Nonetheless, such embodiments are anticipated because of the advantage of not having to involve pumps and motors of different volumetric displacement, this because the required volumetric displacement differential can now be accomplished by setting different rotation speeds, albeit with the required additional complexity of the controller and cables.

Referring now to Fig. 8a, a schematic representation of the apparatus and method of the present invention previously taught in the description of Fig. 1 but wherein an attaehable-as-needed bridging conduit provides a simple means by which the blood filtering system in general and the semi-permeable membrane element 11 (Fig. 1) in particular can be flushed or backwashed.

More specifically, the apparatus is comprised mainly of a blood pump module 1 incorporating a larger displacement pump 3 and a smaller displacement motor 6, a shared driveshaft 9, a semi-permeable membrane filter 2, a plurality of fluid conduits 12, 13, 14, 15 and 16 and a prime mover means 19 that rotates the impellers of the pump 3 and motor 6 by means of their shared driveshaft 9 in a clockwise or forward rotation 48 is shown.

Also seen are (a) an attachable-as-needed bridging conduit 49 (b) a conduit access port 50 incorporated into the conduit 14 ( c ) a conduit access port 51 incorporated into the conduit 15 (d) a suitable cleaning fluid 52 and (e) a cleaning fluid source 53. A bridging conduit 49 provides a simple means by which the blood filtering system in general and the semi-permeable membrane element 11 (Fig. 1) in particular can be flushed or backwashed by pumping the cleaning fluid 52 through them to remove or reduce the buildup of undesirable solute deposits from the membrane surfaces, thereby enhancing the system’s efficiency over time and extending the useable life of the semi-permeable membrane element 11 within it.

In this case, the bridging conduit 49 is temporarily connected to the conduits 14 and 15 by means of the conduit access ports 50 and 51, such that the cleaning fluid 52 can then flow unrestricted between the conduits 14 and 15. This provides the means by which a volume of cleaning fluid 52 equal to the volumetric displacement differential between the pump 3 and the motor 6 can be expelled from the otherwise pressure intensified fluid circuit between the pump 3 and motor 6 into the conduit 15, which is also employed in this system cleaning setup to expel the fluid from the motor 6, in both cases without downstream pressure building resistance. As a result, hydrostatic pressure does not develop to the point where membrane permeation would be initiated within that part of circuit between the pump 3 and motor 6 that incorporates the semi-permeable membrane filter 2. Therefore, no permeate flows into the conduit 16.

Without the permeation, concern for damage to the membrane(s) due to excessive flux through the membrane is eliminated. This allows for the maximizing of flow velocity of the cleaning fluid 52 across the surface but not through the pores of the semi-permeable membrane element 11 , thereby increasing the lifting, dissolving and subsequent removal of the solute deposits that build up over time on the membrane surfaces, blocking its pores. In this way, employment of the attachable-as-needed bridging conduit 49 can enhance the efficiency of the semi-permeable membrane element 11 over time as well as extend its useable life.

It is noted that in like fashion, a suitable storage fluid may be drawn into the semi-permeable membrane filter 2 and held there in order to protect the semi-permeable membrane element 11 during extended periods of non-use or storage.

Referring now to Fig. 8b, a schematic representation of the apparatus and method of the present invention is provided wherein the main difference from that described in Fig.8a is that the impellers of the pump 3 and motor 6 are rotated by means of their shared driveshaft 9 in a counter-clockwise or reverse rotation 54. As a result, the cleaning fluid 52 that flows from the cleaning fluid source 53 now flows through the system in the opposite direction, entering the smaller pump 6 first and exiting the larger pump 3 last, as can seen by the figure’s flow direction arrows.

However, because the volumetric displacement differential is now applied in reverse, additional cleaning fluid 52 is now drawn into the conduit 14 from the conduit 15 via the bridging conduit 49 as volume make- up fluid rather being expelled out of the conduits 14 and 15 as a volume excess fluid, as was the case with Fig. 8a and the used cleaning fluid 52 is expelled from the system as waste through conduit 12. Nonetheless, the physical setup is the same as that taught above in Fig.8a with the understanding that the pump 3 and motor 6 are chosen based on their ability to operate in reverse.

Referring now to Fig. 8c, a schematic representation of the apparatus and method of the present invention is provided wherein the main difference from that described in Fig. 8b is that the bridging conduit 49 (Fig’s 8a and 8b) is, in this case, incorporated as a permanent feature of the system, meaning that the conduit access ports 50 and 51 (Fig. 8a) are not required. Therefore, the now permanent bridging conduit is assigned the new number 55. However, it is noted that because this bridging conduit 55 cannot now be removed when the blood filtration system is in use and connected to the user/patient, a means must be provided for preventing the outflow of blood through it and, therefore, the loss of the necessary hydrostatic pressure and its resultant permeation during the blood filtration mode. While this capability can be implemented in a number of ways, but typically through the use of various valve types, whether with or without manual or more sophisticated control means, the approach employed here involves the insertion of a simple, one-way, intake-only check valve 56 that functions automatically in the sense that it remains closed and holds pressure when the system is in clockwise/forward rotation 48 (Fig. 8a) blood filtration mode but opens to allow for the drawing in of make-up cleaning fluid 52 when the system is taken off-line from the user-patient and operated in its counter-clockwise/reverse rotation 54 cleaning mode as shown here in Fig. 8c. However, it is noted that such optional use of any valve means is not a core requirement of the apparatus and method of the present invention and would add cost and complexity, the latter, also increasing the potential for clogging and failure and would require either manual or some other more complex form of manipulation and/or control. Nonetheless, it’s practicality and incorporation is anticipated,

In other words, the core apparatus and method of the present invention is “valveless” in normal operating mode including when the temporary bridging conduit taught in the descriptions of Fig’s 8a and 8b is employed. It is only when a permanent bridging conduit might be employed as an optional feature that a flow control means such as a one-way valve would be employed during system flushing or storage preparation.

It is noted that with regard to Fig’s 8b and 8c, in the event that semi-permeable filters such as ceramic filters that are not affected by reverse flux are employed, the cleaning fluid 52 may be routed such that the complete filter including its pores are exposed the cleaning (or storage) fluid 52.

Referring first to Fig’s 9a/b, 10a/b/c and 11a/b in general terms, it is noted that certain embodiments of the apparatus and method of the present invention may incorporate a plurality of pump and motor pairs or “sets”. More specifically, a “set” may be comprised of any combination of upstream, larger displacement pumps and downstream, smaller displacement motors arranged and/or cooperating in multiples or sets, rather than only as a single pump working cooperatively with a single motor, This is with the understanding that they adhere to the same operating principles as those embodiments previously described herein, even though their arrangement and/or number of parts may vary. In other words, however the pumps, motors or sets are driven and whether or not they are physically attached to each other, it is understood that a larger volumetric displacement upstream pump or pump set always works in direct cooperation with a mated, smaller volumetric displacement downstream motor or motor set within the same series circuit to establish a continuing, pre-determined and preferably stable volumetric displacement differential between them, just as was the case with the previously described embodiments. To clarify further, as long as their intake and discharge ports and conduits are plumbed to function in the same way and according to the same logic and their operating principles remain the same as the previously described embodiments, then they are understood to be embodiments of the apparatus and method of the present invention, although those shown and described herein do not necessarily, represent all of possible configurations.

While a modest increase in complexity is involved, the use of sets based embodiments offers several important advantages over the previously described embodiments, including the ability to (a) deliver different hydrostatic pressures when more than one type of semi-permeable membrane filter is involved, and (b) allow for different volumes of blood (other than only at a 50/50 ratio for example) to be processed by each of the semi-permeable membranes modules (c) allow for different permeate percentage rates for the individual semi-permeable membrane filters (d) independently change the separate sets flow rates by increasing or decreasing the rotational speeds of the motors. This flexibility adds up to an unusually high degree of user/patient treatment customization and subsequent fine-tuning becomes available.

For ease of comparison to previous figures, improved clarity and keeping in mind that the operating principles of the sets based modules are the same as the non-sets based modules, it is noted that where beneficial, the previous numbering but with the suffixes ‘a” and ‘b” attached is applied to the duplicated but same acting pumps, motors and conduits.

For example the pump 3 and motor 6 of the previous embodiments are represented here in Fig's 9a/b, 10a/b/c and 11a/b by a first pump 3a working cooperatively with a first motor 6a to provide a first continuing, intended and preferably stable volumetric displacement differential and a second pump 3b working cooperatively with a second motor 6b to provide a second continuing, intended and preferably stable volumetric displacement differential. This approach helps maintain clarity.

Referring now specifically to Fig.9a, a schematic representation of an embodiment of the apparatus and method of the present invention is provided that is somewhat similar to that of Fig.4 in that it employs two semi-permeable membranes 2 and 27 but where several significant additional features exist, these being the employment of (a) a dual pump and motor “sets” based blood pump module (b) independently acting permeate flow splitting means offering flexible routing of the permeate and (c) an optional air/gas trap/separator and a backup pressure relief means.

More specifically, the first of these significant differences relates to the use of pump and motor sets as taught in the general preamble to the descriptions of Fig’s 9a/b, 10a/b/c and 11a/b provided above. Here, the impellers of pumps 3a, 3b and motors 6a, 6b are all mounted to the shared driveshaft 9 that is driven by a prime mover such as an electric or other same acting motor 25 with all of these components being incorporated into a blood pump module 57 with the understanding that the core operating principles of this and the previously described embodiments remain essentially the same. The second of these significant differences relates to flow splitting means employed to independently divert some portion of the permeate 18 and 28 if desired. More specifically a first flow splitting means 58 incorporating a flow blending channel 59 (hidden) or equivalent means and a second flow splitting means 60, also incorporating a flow blending channel 61 (hidden) or equivalent means. Each of these may be manually and independently adjustable such that any percentage of its permeate flow from 0-100 percent may be diverted independently into the conduit 15 leading back into the user/patient’s cardio-vascular system 20 with the non-diverted balance from each of the semi-permeable membrane filters 2 and 27 flowing via the conduits 16 and 30 into either the user/patient’s bladder 22, a urostomy bag 23 or a combination of both of these via a suitable, bridging medical appliance 24.

As previously taught, the blood 17 exits the user/patienfs cardio-vascular system 20 via a suitable bridging medical appliance 21 and flows via the conduit 12, and its branches 12a and 12b into the blood pump module 57. While ratios may vary, in this particular embodiment a nominal first portion of approximately 50 percent of the blood 17 flows into a first pump 3a through its intake port 4a and back out of its discharge port 5a from where it continues on through a conduit 13a into the semi-permeable membrane filter 2 where it becomes separated into two streams.

A first, retentate stream of blood 17 flows across but not through the semi-permeable membrane element 11 within the first semi-permeable membrane filter 2 and upon exiting, continues via a conduit 14a into a first motor 6a through its intake port 7a, back out of its discharge port 8a and from there continues on through a branch 15a of the conduit 15 leading back through a bridging medical appliance 21 into the user/ patient’s cardiovascular system 20. It is noted that as with previous embodiments, fluid pressure is intensified within the circuit incorporating the semi-permeable membrane filter 2 located between the pump 3a and the motor 6a.

At the same time, a first permeating stream, being the earlier described solution of excess water and undesirable solutes from within the bloodstream, having now passed through the pores of the first semi- permeable membrane element 11 as permeate 18, then flows out of the semi-permeable membrane filter 2 into the conduit 16 where it encounters the first of the adjustable flow splitting means 58, through which it may either (a) continue to flow in its full volume via the conduit 16 into the user/patienfs bladder 22, a urostomy bag 23 or a combination of both of these via the bridging medical appliance 24 or (b) have any portion of it’s volume diverted by the first adjustable flow splitting means 58 into the conduit 15 leading back through the bridging medical appliance 21 into the user/patient's cardio-vascular system 20.

The purpose of flow blending channel 59 is to cause the two separate streams that merge together in the flow splitting means 58 to blend more fully in order to form a more homogenous mixture before re- entering the user/patient’s cardio-vascular system 20.

Simultaneously, a nominal second portion of approximately 50 percent of the blood 17 flows into a second pump 3b through its intake port 4b and back out of its discharge port 5b from where it continues on through a conduit 13b into the second semi-permeable membrane filter 27 where it becomes separated into two streams.

Here a second, retentate stream of blood 17 flows across but not through the semi-permeable membrane element 11 within the second semi-permeable membrane filter 27 and upon exiting, continues via a conduit 14b into a first motor 6b through its intake port 7b, back out of its discharge port 8b and from there continues on through a branch 15b of the conduit 15 leading back through a bridging medical appliance 21 into the user/patient’s cardio-vascular system 20. Again, it is noted that as with previous embodiments, fluid pressure is intensified within the circuit incorp-orating the semi-permeable membrane filter 27 located between the pump 3b and the motor 6b.

At the same time, a second permeating stream, again being a solution of excess water and undesirable solutes from within the bloodstream, having now passed through the pores of the second semi-permeable membrane element 11 as permeate 29, then flows out of the semi-permeable membrane filter 27 into the conduit 30 where it encounters the second of the adjustable flow splitting means 60, through which it may either (a) continue to flow in its full volume via the conduits 30 and 16 into the user/patient’s bladder 22, a urostomy bag 23 or a combination of both of these via the bridging medical appliance 24 or (b) have any portion of it’s volume diverted by the second adjustable flow splitting means 60 into the conduit 15 leading back through the bridging medical appliance 21 into the user/patient’s cardio-vascular system 20.

The purpose of flow blending channel 61 is to cause the two separate streams that merge together in entering the user/patient’s cardio-vascular system 20.

Although not a core, functional requirement of the apparatus and method of the present invention, an optional air/gas separator and shutoff module 62 for safely trapping and removing gas bubbles such as air or nitrogen from the blood 17 and an optional backup pressure relief and shutoff means 63 for ensuring pressure is limited to intended levels are installed in-line into the conduit 15 before the blood 17 re-enters the user/patient’s cardio-vascular system 20, in both cases for reasons of user/patient health and safety.

In practice, this relatively simple, embodiment of the apparatus and method of the present invention is intended to provide a means for eliminating the need for the high purity and expensive substitution fluid normally associated with the prior art hemofiltration process and delivered at increased risk to the user / patient’s cardio-vascular system. Instead, this and similar embodiments of the present invention offer the opportunity to replenish the user/patients cardio-vascular system 20 with its own natural, internally generated replacement fluid, while also offering an apparatus that is both highly customizable and adjustable in terms of matching it to a user/patient’s unique needs.

Other advantages lie in the opportunity it presents to (a) allow for the benefits of high-flux hemofiltration without the need for a substitution fluid that that process normally requires (b) control both the permeation ratio and speed, this being possible because the permeation ratio is equal to the preset displacement differential ratio, which in turn can be controlled by changing the prime mover speed (c) significantly reduce or potentially even eliminate the frequency of aggressive, short-duration, conventional hemodialysis treatments, thereby reducing stress and strain on the user/patient’s physical well-being by allowing for longer duration, less aggressive treatment cycles (d) employ different combinations of specialized membranes requiring or benefiting from different hydrostatic pressures (e) gain the obvious increased mobility and lifestyle benefits of a more portable/wearable device and (f) benefit from access to a much simpler, lower cost and therefore, more widely available apparatus and method.

It is, nonetheless, anticipated that other embodiments including more complex institutionally based apparatus might also incorporate pressure regulators as an alternative means of gaining the ability to apply different hydrostatic pressures to each semi-permeable membrane filter. However, such variations and added complexity do not change the novel function and core operating principles of the apparatus and method of the present invention.

Referring now specifically to Fig.9b, a schematic representation of a blood pump module 64 is shown with an alternative pump order to that of the blood pump module 57 (Fig. 9a) but with all else being essentially equal to the overall system layout of Fig. 9a. Here, the pumps and motors order of physical placement is 3a, 6a, 3b and 6b as compared to that of Fig. 9a where their order of physical placement was is 3a, 3b, 6a and 6b but with the note that although the physical positioning of their conduits has also shifted to match, their connections have not. In effect nothing has changed from that taught in the description of Fig.9a, other than the physical location of some components.

Referring now specifically to Fig. 10a, a schematic representation of the apparatus and method of the present invention is provided wherein the only significant difference from that described in Fig. 9a is that the blood pump module 57 (Fig. 9a) is replaced with a blood pump module 65 wherein the impellers of the pumps 3a and 3b are fixedly attached to a first shared driveshaft 9a driven by the prime mover motor 43 and the the impellers of the motors 6a and 6b are fixedly attached to a second shared driveshaft 9b driven by the motor 25. The prime mover motors 43 and 25 in this embodiment have independent variable speed capability such that the pump and motor set 3a/6a and the pump and motor set 3b/6b can be rotated at varying speed ratios with the effect that the volumetric displacement differentials for the pump and motor set 3a/6a and the pump and motor set 3b/6b can be changed as needed.

In this way, this and similarly configured embodiments have the advantage of setting or changing the volumetric displacement ratio and, therefore, the permeate percentage for the semi-permeable membrane filters 2 and 27 together by increasing or decreasing the rotational speeds of the pumps or the motors by different amounts. Also, the overall system flow rate can be changed by increasing or decreasing the rotational speeds of the pump and motor sets by the same amount. It is noted, however, that independent adjustment of the the volumetric displacement ratio and, therefore, the permeate percentage for the semi- permeable membrane filters 2 and 27 is not a feature of this particular embodiment.

Referring now to Fig. 10b, a schematic representation of a blood pump module 66 is shown with an alternative pumps and motors order to that of blood pump module 65 (Fig. 10a) wherein the impellers of the pump and motor set 3a/6a are fixedly attached to a first shared driveshaft 9a driven by an electric motor 43 and the impellers of pump and motor set 3b/6b are fixedly attached to a second shared driveshaft 9b driven by an electric motor 25 with both motors 43 and 25 having independent variable speed capability. In this embodiment it is possible to independently change each of the cooperating pump/motor sets filtration flow rates, however, setting or changing permeate percentage rates is not a feature, as it was in Fig. 10a.

Referring specifically to Fig. 10c, a schematic representation of a blood pump module 67 is shown wherein the only difference from that described in Fig. 10b is that the pump and motor set 3a/6a and the pump and motor set 3b/6b are not physically attached to each other. A benefit of this approach is that it allows for the use of two of the previously described core heart pump modules 1 as a means of adding capabilities and flexibility without having to design and build different blood pump modules such as those described in Fig’s 10a and 10b.

Referring now spedfically to Fig. 11a, a schematic representation of the apparatus and method of the present invention is provided wherein various features and capabilities, whether previously referenced or new to this embodiment are combined in a single, more fully featured embodiment. A plurality of the components associated with these features are also now capable of two-way wireless communication and are monitored and controlled by an wireless control means 68 and so, are assigned new identifying numbers. Nonetheless, it is understood that these various, optional components and capabilities do not change the basic or core operating principles of the apparatus and method of the present invention as initially taught in the descriptions of Fig’s 1 and 2.

The main purpose of Fig. 11a and its associated description is to draw attention to the fact that any number of non-core components and capabilities, often comprising known, third-party supplied technology may, for various reasons, be incorporated into any number of systems incorporating the apparatus and method of the present invention. Therefore, the examples shown here are presented as an overview only. These may fall into several categories such as but not limited to components or apparatus that (a) address user/patient safety (b) add substitution or other constituents to the blood stream (c) sense/monitor aspects of the user/patient’s blood (d) monitor apparatus conditions and parameters or (e) provide access points where medical practitioners can draw blood samples or carry out injections and, in this case monitor and control these with typically known and established, third party wireless monitoring and control means.

Examples of these, include but are not limited to: a multi-channel infusion pump 69 capable of infusing blood treatment or reconstituting components such as minerals, anti-coagulants or other constituents prescribed by a medical practitioner; an air/gas trap/separator module 70 for safely removing gas bubbles such as air or nitrogen from the blood 17 before it re-enters the user/patient’s cardio-vascular system 20; a pressure relief valve 71 provided, in this case, as a backup safety device in consideration of the fact that the high pressure produced upstream by the apparatus has already been reduced to negligible by the apparatus' energy recovery means, as was previously taught; and a solenoid type shut-off valve 72, employed to provide a final safety shut-off means before the blood 17 flows back via the conduit 15 into the user/patient’s cardio-vascular system 20. A pulsation dampener 73 is mounted inline in the conduit 12 that carries blood out of the user/patient's cardio-vascular system 20 to a wireless communication capable blood pump module 74. The pulsation dampener 73 smooths the pulsing flow of blood produced by the user/patienfs heart to better match the smooth flow produced by the motor 75.

The blood pump module 74 is equivalent to the blood pump module 65 (Fig. 10a) except that here it incorporates a multi-functional, wireless controller means 68 in communication with and control of the above mentioned non-core component examples, each shown here incorporating a representative, generic two-way wireless communication node 76. Three flow splitting means 77, 78 and 79 are employed in this embodiment, each also incorporating a suitable wireless communication node 76.

Also, as was the case with the apparatus’ described in Fig. 5, a non semi-permeable membrane based blood treatment means 31 has optionally been incorporated into this more fully featured blood filtration and treatment system example which, nonetheless, incorporates and is built around the core operating principles of the apparatus and method of the present invention. More specifically, the filtered, retentate blood 17 passes out of the second semi-permeable membrane filter 27 via a conduit 80 into the third adjustable flow splitting means 79, which, as with the other flow splitting means 77 and 78 as well as those taught in the descriptions of previous figures, incorporates a suitable flow blending channel 81 or equivalent means and wherein any percentage from 0 to 100 percent of the filtered, retentate blood 17 may be routed either directly into a conduit 82 leading to the intake port 7b of the second pump 6b or first be routed via the conduit 83 into the previously referenced blood treatment or reconstituting means 31 for processing before then being returned via the conduit 84 to the flow splitting means 79 for return via the conduit 82 the intake port 7b of the second pump 6b, once again in accordance with the core operating principles as were taught in the descriptions of Fig’s 1 and 2 and incorporated into the all the other previously described embodiments of the apparatus and method of the present invention.

It is noted, however, that an equivalent, non-wireless embodiment employing same acting hard-wiring means could also be employed to the same effect, whether for preference or as a means of preventing the possibility of un-authorized “hacking” to gain control of the system, whether to disrupt, sabotage or access user-patient information.

It is still further noted that the reference numbers for the pumps 3a, 3b, and motors 6a and 6b are all shown here in Fig. 16a in order to facilitate comparison with Fig. 11b below.

Referring now specifically to Fig. 11b, a schematic representation of a blood pump module 85 is shown wherein each of the pumps 3a, 3b and motors 6a and 6b are driven by their own variable speed motors 86, 87, 88 and 89 but with all else being essentially equal to the overall system layout of Fig. 11a. In this way, this and similarly configured embodiments have the advantage of being able to (a) independently set and adjust the pump and motor sets 3a/6a and 3b/6b volumetric displacement differentials and, therefore, the permeate percentages for the semi-permeable membrane filters 2 and 27 (b) independently change their flow rates by increasing or decreasing the rotational speeds of the individual pumps and motors and (c) independently set and adjust the filtration rates of the semi-permeable membrane filters 2 and 27.

However, it is noted that this embodiment does not feature the energy recovery capability associated with the transfer of energy between larger displacement pumps and smaller displacement motors as seen in some previously described embodiments. Nonetheless, this type of configuration is foreseen for use with less portable systems such as in blood treatment clinics or hospitals where energy saving may be a lower priority than the gained feature(s).

We are reminded, however, that regardless of how the individual pumps and motors are positioned in relation to each other in any embodiment of the apparatus and method of the present invention, the term “set” always refers to an upstream, larger volumetric displacement pump working in cooperation with a downstream, smaller volumetric displacement motor within the same circuit and in accordance with the same operating principles as described in the basic, core embodiment described in Fig’s 1 and 2.

Referring now to Fig. 12a, a schematic representation of a preferred embodiment of the apparatus and method of the present invention similar to that described in Fig. 9a is provided. As with that of Fig. 9a, key features of this particular embodiment include its ability to employ two semi-permeable membrane filters 2 and 27, each with different hydrostatic pressure requirements and its ability to return a volume of permeate, here being primarily excess water, to the user patient/s cardio-vascular system. This relates directly to key objectives of this apparatus and method, which are to eliminate the need for providing and administering a substitute or replacement fluid into the user/patient’s cardio-vascular system, as is normally the case with prior art hemofiltration processes as well as to eliminate the need for or at least reduce the frequency of hemodialysis or hemodiafiltration treatments.

Although there is no change in the core operating principles of the apparatus and method, a key and novel feature of this embodiment is the elimination of one of the pumping chambers within a modified blood pump module 90, this being accomplished by merging the functions of the normally separate pump 6a and motor 3b into one rather than two chambers, thereby further reducing the apparatus complexity.

Because the operating principles employed here have been taught in previous embodiments and because of the significant similarity in layout to Fig. 9a the following description instead focuses on a detailed analysis of flow volumes, expressed as volumetric units (vu) and their associated hydrostatic pressures, the latter expressed as millimetres of mercury (mmHg) within this simple but flexible dual filter system. It is noted, however, that the volumes and pressures indicated here are strictly arbitrary and are used only to facilitate understanding and not to reflect actual or anticipated treatment recommendations.

In this example, 100 vu of blood 17 initially leaves the user/patients cardio-vascular system 20 via a suitable, bridging medical appliance 21 and is drawn via the conduit 12 into and through the pump 3a, which then propels it downstream via the conduit 13 into a first relatively low flux (higher hydrostatic pressure requirement) semi-permeable membrane filter 2 where, as previously taught, it becomes separated into two streams.

The first stream comprised of 70 vu of now partially filtered blood 17 flows through and out of the semi- permeable membrane filter 2 into the conduit 14 and on into the smaller displacement 70 vu capacity motor 6a at a hydrostatic pressure of 2500 mmHg, that being the amount of hydrostatic pressure needed to initiate and maintain the hydrostatic pressure required by membrane 11a to allow convective transport of the permeate through the pores of the membrane 11a, this hydrostatic pressure being developed as a direct result of the volumetric displacement differential, as was previously taught. Also because of the volumetric displacement differential between the pump 3a and the motor 6a, a second 30 vu stream, it being permeate 18, in this case being comprised mainly if not exclusively of excess water, passes through the pores of the membrane 11a and out of the semi-permeable membrane filter 2 at a typically negligible pressure via a first conduit section 16a (of the conduit 16 of Fig. 9a) and a conduit branch 91 into the conduit 15 through which it is then returned to the user/patients cardio-vascular system 20 via the bridging medical appliance 21 at a typically negligible pressure determined by any back pressure that may be encountered from the user/patients cardio-vascular system 20.

It is noted that in this particular example the permeate flows in its 30 vu entirety through the conduit branch 91 with none flowing into the second conduit section 16b. This is due to the use of a flow splitting means, here being an internally branched "Y" insert 92 located at the point where the conduit 16 is seen to branch into two. More specifically, the insert 92 employed in this embodiment has the ability to variably distribute the flow of permeate 18 either by some such means as being rotated in place or by replacement with another insert from an anticipated available range of inserts incorporating branches incorporating various other flow biasing ratios. At a more basic level, unequal flow biasing at the "Y" branch may be incorporated into the apparatus’ conduits at a given ratio and not be adjustable, replaceable or rotatable or may even have one branch blocked. In other words, there are a plurality of means by which the return of permeate to the user/patient’s cardio-vascular system 20 can be accomplished without the need for any valves or other control means, although that option may be employed as with the example of Fig. 12c that follows. In such cases it is anticipated that blood pump modules would be made to order with the pump to motor displacement ratios being specified as needed, such a strategy being well suited to the rapidly emerging additive manufacturing (3D printing) approach.

Before proceeding further, we are first reminded that even though this embodiment incorporates two pump/motor “sets" the roles of the normally separate pump 6a and motor 3b are here merged into a single, dual purpose component 6a/3b but, for the benefit of clarity and comparison they continue to be referred to as the motor 6a and the pump 3b.

Returning now to the flow progression, 70 vu of the blood 17 that was initially processed by the semi- permeable membrane filter 2 is now propelled downstream by the second pump 3b via a conduit 93 into the second, relatively high flux (lower pressure requirement) semi-permeable membrane filter 27 where, as with the first semi-permeable membrane filter 2, it becomes separated into two streams. The first 60 vu retentate stream of now re-filtered blood 17 passes through and out of the semi-permeable membrane filter 27 from where it flows via a conduit 94 into the smaller, 60 vu displacement motor 6b. In this case the hydrostatic pressure in the series circuit between the pump 3b and the motor 6b and incorporating the semi-permeable membrane filter 27 is 1000 mmHg, once again this is determined by the amount of hydrostatic pressure needed to initiate and maintain the hydrostatic pressure required by the membrane 11b to allow convective transport of the permeate 29 through the pores of the membrane 11b with this hydrostatic pressure being developed as a direct result of the volumetric displacement differential, as was previously taught.

Because of the volumetric displacement differential between the pump 3b and the motor 6b, a second 10 vu stream of permeate 29, in this case being a solution comprised of excess water and a range of targeted, undesirable solutes such as urea, creatinine and potassium passes through the pores of the membrane 11b and out of the semi-permeable membrane filter 27 at a typically negligible pressure via the conduit 30 into a second flow splitting "Y" insert 95 located at the point where the conduit 30 interconnects with (a) a conduit section 16c that feeds, via a suitable bridging medical appliance 24, into the user/ patient's bladder 22 and/or urostomy bag 23 and (b) a conduit 96 that feeds into the conduit 15 through which it is then returned to the user/patients cardio-vascular system 20.

In this example the permeate flows in its 10 vu entirety through the conduit 16c with none flowing into the conduits 96 and 15 due to the selected flow biasing of the flow splitting "Y" insert 95 or equivalent flow splitting means.

Although all of the permeate 18, in this case being comprised mainly if not exclusively of excess water, flows back into the user/patients cardio-vascular system 20 in order to eliminate the need for a replacement fluid during hemofiltration treatment, it is understood that a percentage of the permeate 18 may also be diverted by the flow splitting "Y" insert 92 to the patient’s bladder 22 and/or urostomy bag 23 via the conduit sections 16a and 16b, whether for balancing or fine-tuning the treatment involved or some other reason, noting that this would result in a corresponding, lower volume of blood 17 being returned to the user/ patient’s cardio-vascular system.

To summarize, the 60 vu of of blood 17 that was returned to the motor 6b from the semi-permeable membrane filter 27 is then propelled through it and toward into the conduit 15 at typically negligible pressure due to the energy recovery mode taught in the descriptions of earlier figures but subject to any downstream back pressure. When combined with the 30 vu of mainly water permeate merging from the conduit 9 the following may be concluded: The example described here in Fig. 12b results in 90 vu of the original 100 vu of blood 17 being returned to the user/patient’s cardio-vascular system to begin the cycle again for the duration of the treatment period whereas 10 vu of the original 100 vu is separated as permeate in the form of urine and destined for disposal.

As with Fig. 9a and although they are not a core requirement of the apparatus and method of the present invention, an air/gas separator and shutoff module 62 employed for safely trapping and removing possible gas bubbles such as air or nitrogen from the blood 17 and a backup pressure relief and shutoff means 63 for ensuring blood re-entry pressure is limited to intended negligible levels are installed in-line into the conduit 15 before the blood 17 re-enters the user/patient's cardio-vascular system 20, in both cases for reasons of user/patient safety.

With regard to the use of "Y" type flow splitting means, these may incorporate different sized orifices leading into the branches whether these branches be the same or different diameters. A significant advantage to this approach would involve making available a series of inserts or insert sets, with a set incorporating different orifice size such that flow splitting ratios could be established and fitted as needed into the apparatus at the "Y" where the conduit branches. Ideally, the orifices would be sized such that they do not restrict, cause back pressure or otherwise reduce overall flow. Clearly, this approach could also be applied to any number of other embodiments as well.

Referring now to Fig. 12b, a chart displaying a breakdown of blood and permeate flows in terms of volumetric units (vu) and associated hydrostatic pressures within each of the pumps, motors and fluid carrying conduits is provided for the benefit of clarity. It is offered as a convenient summary of the information available within the description of Fig. 12a.

Referring now to Fig. 12c, a variation of the internally branched "Y" insert 92 taught in the description of Fig. 12a is shown wherein an adjustable valve means 97 allows for the setting or fine-tuning of any volume between 0 and 100 percent of the permeate flowing from one or both of the semi-permeable membrane filters 2 and 27 into the blood return flow conduit 15 and/or the user/patient’s bladder 22 and/or urostomy bag 23.

Referring now to Fig. 12d, a schematic representation of an alternative to the modified blood pump module 90 of Fig. 12a employing a dual purpose, single chambered pump/motor 6a/3b is presented. Here, a blood pump module 98 has the pump 6a and the motor 3b remaining separate but with a conduit 99 connecting them directly. Otherwise the apparatus and fluid flows are the same as those taught in the description of Fig. 12a. The conduit labelling numbers 16a, 30, 91, 96, 16b and 16c are shown to ensure clarity when comparing this figure to Fig. 12a.

Referring now to Fig. 13, a schematic representation of the apparatus and method of the present invention similar to that described in Fig. 2 is provided but wherein a modified blood pump module 100 incorporates a pneumatic motor 101 and a suitable isolation barrier means 102, the latter being employed to assure that no air or equivalent pneumatic driving fluid 104 can migrate or otherwise move from the pneumatic motor 101 into the blood 17 flowing through the motor 6. The output of the motor 25 is, in this embodiment, delivered through an attached over-running clutch 103.

More specifically, the pneumatic motor 101 is employed as the priority driving means for use whenever a pressurized air source is available and connected, in this case via a conduit such a quick-connect air hose assembly 105. When a pressurized air source is not in use, the pneumatic motor 101 is backed up by a motor 25 and over-running clutch 103 sub-assembly. With this arrangement, even when the attachable-as- needed motor 25 and over-running clutch 103 sub-assembly is physically connected, the over-running clutch 103 feature allows the pneumatic motor 101 to power the device without having to overcome resistance from the inactive motor 25 . The over-running clutch 103 is also employed to prevent the locking up or stalling of the apparatus when it is operated in reverse mode for flushing/ backwashing purposes for embodiments designed with that capability, as was taught in the description ofFig’s 8a/b/c, recognizing that this condition could occur due to the existence of one-way only flow valves that could be present in a pressurized air flow source employed as the prime mover.

In this particular embodiment, exhaust air from the pneumatic motor 101 is vented to the atmosphere via the conduit 106. As with previously described embodiments, the pump 3 the motor 6 and, in this case, the pneumatic motor 101 also are all driven by the shared driveshaft 9. The operating principles of this embodiment remain the same as described for previous embodiments such as that taught in the description of Fig. 2.

The flexibility that this and similarly constructed embodiments provide in their ability to be driven by a range of prime movers offers significant advantages and benefits. For example, by being driven by a quick- connect, bedside located, mains or battery powered electric motor based module during the night and by that same drive module at an office desk during working hours, thus allowing for a much improved opportunity for a normalized work/lifestyle and a lowering of stress on the user/patients internal systems due to opportunity for less aggressive treatment cycle times.

Fig. 14 and it's associated identification numbers 107-122 have been removed.

Referring now to Fig. 15, a schematic representation of the apparatus and method of the present invention similar to that described in Fig. 13 is provided wherein a hydraulic motor 123 rather than a pneumatic motor is employed to rotate the pump 3 and motor 6 of a modified blood pump module 124. As with the pneumatic embodiment of Fig. 13, care is taken here to ensure there is no possibility of crossflow, contamination or leakage between the blood being pumped and the hydraulic fluid driving the blood pump module 124. In this case, this is accomplished by employing a conventional, application certified magnetic drive 125 to couple the hydraulic motor 123 to the shared driveshaft 9 (Fig. 13) that is here referred to as a two-part shared driveshaft 9a and 9b because, although physically separated by the magnetic drive 125, it continues to allow all the rotating elements of the blood pump module 124 to be driven as if by the continuous shared driveshaft 9 (Fig. 13) such that the same operating principles as described for previous embodiments are maintained. It is noted that other same acting means as a magnetic drive could also be employed for the purpose.

In this hydraulically driven embodiment it is also seen that the driving fluid now flows within a closed circuit rather than an open circuit such as was the case with the pneumatically driven embodiment of Fig. 13. To that end, there are now two conduits connecting this Fig. 15 apparatus with a suitable, external hydraulic prime mover (not shown). More specifically a hydraulic driving fluid 126 flows into the hydraulic motor 123 via an intake conduit 127. However, rather than being expelled as was the case with the pneumatic embodiment, here the driving fluid 126 is returned to the connected hydraulic prime mover via a return conduit 128 and continues to cycle through both of these driving and driven components of the combined system for the duration of the filtration treatment. Otherwise, the purpose, function and operating principles of the apparatus and method described in Fig. 13 and here in Fig. 15 are essentially the same.

Fig. 16 and it's associated identification numbers 129-135 have been removed.

Referring now to Fig. 17, a schematic representation of a blood pump module 136 similar to that seen in Fig. 15 is provided but wherein an additional pump has been incorporated for the purpose of moving urine permeate under a positive pressure. More specifically, an additional pump 137, also being driven via the driveshaft 9a, is employed to pressurize the flow of urine permeate that would otherwise could, in some setups, be flowing without significant positive pressure from a connected semi-permeable membrane based filtration means when, for example, it must be raised from a lower location to a higher location such as a wearer’s thigh level urostomy bag or their natural, corporeal bladder. In this embodiment the urine flows into the pump 137 through an intake conduit 138 and is propelled out through an output conduit 139.

It is noted that the location of the additional pump 137 does not need to be restricted to it’s current location nor does it necessarily need to be connected directly to a common shaft or, for that matter, any other aspect of the blood pump module as it is not an aspect of the core operating principles. It is also noted that this same means and capability could be incorporated into other embodiments of the present invention including pneumatically driven versions such as that described in Fig. 13.

Referring now to Fig. 18, a conceptual, three dimensional representation of a user-worn belt pack style embodiment 140 of the present invention is described solely for the purpose of highlighting that the apparatus and method of the present invention, when compared to the prior art associated with popular blood treatment processes used to remove excess water and undesirable solutes, provides the means by which the mobility, quality of life and treatment related stress and strain upon the body of a user/patient can all be significantly improved and the burden upon government funded and private insurance treatment programs and facilities in general can also be significantly reduced.

In this conceptual example there is seen a basic device comprising a first module 141 incorporating the pump(s), motor(s) and associated conduits that represent the key aspects of the apparatus of the present invention as well as a variable selection of other non-core components such as but not necessarily limited to an electric motor prime mover, a pressure relief means and a air/gas separator; a second module 142 comprising a user/patient replaceable semi-permeable membrane cartridge 143 and a user/patient replaceable urostomy cartridge 144 that is drainable via a port 145 and may also be disposable such that it can either be continuously drained to a conventional urostomy bag or, from time to time, by other appropriate waste disposal means but also can serve as a short-term disposable reservoir to allow for maximum mobility; a rechargeable battery module 146 to power the motor and any other components such as such as a wireless two-way communication and control means 147 as well as various sensors or alarms that may also be incorporated into the apparatus. Also shown is a blood delivery and return port 148 for connecting a suitable, bridging medical appliance 21 (Fig’s 3 and 4) such as a catheter, fistula or other similar means normally selected by a qualified medical practitioner and an attached, adjustable belt 149 or same serving harness that allows the user/patient to wear the device and travel about untethered. All component and conduit inter-connections, as well as their fluid flows and operating principles are understood to be in accordance with those generally taught in previously described figures.

Other variants including more feature inclusive devices that may or may not be as portable, as well as miniaturized versions involving the user/patienfs heart as the prime mover and bladder as the waste disposal means are fully anticipated.

Referring now to Fig. 19, a schematic representation of a blood pump module 150 that combines features and capabilities of the blood pump modules of Fig’s 12a, 13 and 15 is presented. In effect, this embodiment provides a blood pump module 150 that is suitable for use within a dual semi-permeable membrane based blood filtration system that is capable of employing a plurality of different semi-permeable membrane types including those requiring different hydrostatic pressures, said system being powered either by an external hydraulic or pneumatic type prime mover or some other similarly acting portable or fixed supply means.

More specifically, as was previously taught in the description of Fig. 12a, the pump 3a, hybrid motor/ pump 6a/3b and motor 6b provide the means by which blood can flow through a partially partitioned circuit into a plurality of semi-permeable membrane filters at different hydrostatic pressures. Also, in the same way as was taught in the descriptions of Fig's 13 and 15, either an air driven pump 101 or as a liquid driven pump 123 can be employed to rotate the impellers of the pump 3a, hybrid motor/pump 6a/3b and motor 6b via a shared driveshaft 9 (or a same acting coupled one such as 9a and 9b of Fig. 15) or by a mechanical means such as a driveshaft attachable motor 25.

It is noted that a blood pump module 150 such as that described here could be incorporated into a variant of a portable blood pump filtration system such as the user-worn apparatus of Fig. 18 with the result that a user/patient could choose to power the apparatus by either an externally connected prime mover or by the built-in means.

Referring now to both Fig’s 20 and 21 , these figures are described together for the benefit of improved clarity. They represent a sectional side view (Fig. 20) and a sectional end view (Fig. 21) of the same assembly, that being one example of various possible positive displacement pump and motor components that can be employed by the blood pump module 1 as taught in Fig’s 1, 2, 3.

In this example, the apparatus’ prime mover function is provided by either ( a) an attached motor 25 as described in Fig. 2 or (b) by a flow of blood 17 flowing under natural pressure from the user/patient’s cardio-vascuiar system 20 (Fig. 3) powered by the heart 26 (Fig. 3) as was taught in the description of Fig. 3 or (c) some combination of both.

Because the function, operating principles and blood 17 flow path of the apparatus and method in general were previously taught in the detailed descriptions of Fig’s 1, 2, 3 and others, the focus here is limited to providing specific details on this one example of a pump/motor type that may be incorporated into a blood pump module 1, with the gerotor type being chosen because of its ability to be driven by either a mechanical prime mover or hydraulically, in this case by blood 17 flow.

The blood pump module 1 in this particular embodiment is understood to be produced using the rapidly evolving additive manufacturing method and, to that end, has been designed and simplified to the degree that it could be produced in a single, continuous or near continuous process and using a single or minimal number of materials. Ideally, the material, for example a ceramic, would be non-reactive so that it does not interact with the blood in a way that causes or increases the need for anti-coagulant use. For the benefit of clarity and ease of comparison with Fig’s 1 and 2 and 3 even though the build in this case may be continuous, the various features of the apparatus are defined as individual components based upon their function and as defined by those of the previous figures.

Specifically, a pump 151 that is functionally equivalent to the pump 3 (Fig. 1) and a motor 152 that is functionally equivalent to the motor 6 (Fig. 1) rotate freely but with the least possible clearance within their respective pumping cavities 153 and 154 located within a shared housing 155. As with the apparatus described in Fig. 1, a fixed volumetric displacement differential exists between the pump 151 and the motor 152 and the operating principles remain the same.

This particular embodiment employs well known, proven and highly documented gerotor (or similar micro annular gear type) positive displacement pumps/motors that employ a rotor within a rotor design, although other pump and motor types such as, but not limited to, external gear type pumps/motors could be employed as well. More specifically, the pump 151 incorporates an inner rotor 156 and outer rotor 157 and the motor 152 incorporates an inner rotor 158 and outer rotor 159. The inner rotors 156 and 158 are driven by a shared driveshaft 160 (equivalent to the driveshaft 9, Fig. 1) noting that due to the additive manufacturing strategy, the inner rotors 156 and 158 and driveshaft 160 are formed here as a single part. The driveshaft 160 also rotates essentially freely but with the least possible clearances within a bore 161 running through the housing 155 and it is seen that the bore 161 and the pumping cavities 153 and 154 are formed as a single cavity, again due to the additive manufacturing strategy. The driveshaft ends 162 and 163 are flared and fit with the least possible clearances that allow for essentially free rotation of the driveshaft 160 within corresponding flared areas of the bore 161 as a means of better maintaining alignment and increasing sealing effectiveness.

If the prime mover is to be a motor 25 as with that of Fig. 2, then the driveshaft 160 may extend out beyond the housing 155 and incorporate a non-slip motor coupling means such as a splined driveshaft extension 164 as shown here. If, however, the prime mover is to be the inflow of pressurized blood 17 via the conduit 12 from the user/patient’s cardio-vascular system 20 (Fig. 2) then the driveshaft extension 164 would not be needed unless used for connecting to a backup or alternative prime mover means such as the motor 25.

Unrestricted conduits such as channels 165, 166, 167 and 168 within the housing 155 deliver blood between their respective intake and discharge ports 4, 5, 7 and 8 and the pumping cavities 153 and 154.

As is the norm with gerotor type pumps and motors, the blood 17 is propelled through the pump 151 and motor 152 by the initial expansion and subsequent contraction of gaps 169 and 170 between the always meshed teeth of the inner rotor 156 and outer rotor 157 of the pump 151 and between the always meshed teeth of the inner rotor 158 and outer rotor 159 of the motor 152.

It is noted that from this point on in those parts of the description relating specifically to Fig. 21, because the pump 151 and motor 152 are essentially identical in construction and operating principles except for their different volumetric displacements and because, being an end view one is hidden, their descriptions going forward are merged where and when suitable by referencing the part numbering for the pump 151 and motor 152. together in this manner [151/152].

The gear-toothed inner rotor 156/158 and the gear-toothed outer rotor 157/159 are assembled in a gear- within-a-gear arrangement that is mounted into the pumping cavity 153/154 within the shared housing 155 such that the outer circumferential face of the outer rotor 157/159 forms a very close but still freely sliding fit with the inner circumferential face of the pumping cavity 153/154. The housing 155 incorporates a preferably unrestricted intake port 4/7 and intake channel 165/167 leading into the pumping cavity 153/154 and a preferably unrestricted discharge channel 166/168 and its associated discharge port 5/8 leading back out of the pumping cavity 153/154, these ports 4, 5 ,7 and 8 being the means by which the blood pump module 1 is integrated into the flow circuit of the overall blood filtration system.

The inner rotor 156/158 is formed as a single part with the shared rotating shaft 160 and draws the outer rotor 157/159 around with it due to the meshing of their respective teeth, such that both rotate in the same direction and noting that each of the inner rotor’s 156/158 teeth is always in full, gapless sliding and fluid sealing contact with the toothed inner face of the outer rotor 157/159. As is standard with gerotor type pumps/motors, the smaller diameter inner rotor 156/158 has one less tooth than the larger diameter outer rotor 157/159 with the centre line of the inner rotor 156/158 being located at a fixed eccentricity from the centre line of the outer rotor 157/159 such that a tooth-separated, growing gap 169/170 is formed between the inner and outer rotor within the pumping cavity 153/154 with the gap 169/170 being widest at position 171 (Fig. 21) located directly opposite position 172 (Fig. 21) where the gap 169/170 is small to negligible.

More specifically, as the meshed inner and outer rotors rotate, the teeth of the inner rotor 156/158 and outer rotor 157/159 begin to diverge at that location where the intake conduit 165/167 opens, typically as a channel, into the pump/motor 151/152, thereby creating an expanding gap 169/170 between them. This results in the development of a partial vacuum, thus drawing blood 17 in and subsequently trapping it and moving it forward in the tooth separated gap compartments that continuously form and grow between the teeth of the inner rotor 66/68 and outer rotor 157/159 on the intake side of the pump/motor 151/152. At the location 171 where the expanding gap 169/170 reaches it's maximum, its volumetric expansion then shifts to volumetric contraction as the teeth of the inner rotor 156/158 and outer rotor 157/159 now begin to converge resulting in the progressive reduction of the gap 169/170 and its corresponding volume between the meshing teeth of the inner rotor 156/158 and outer rotor 157/159 on the discharge side of the pump/ motor 151/152. This results in the blood 17 being forced out of the pumping cavity 153/154 into the discharge conduit 166/168 and on out of the blood pump module 1 through the discharge port 5/8.

It is noted that because of the combination of (a) very minimal gaps and tight tolerances between the adjacent, meshing surfaces of the inner rotor 156/158 and outer rotor 157/159 as well as between the circumferential and side walls of the rotors 156/158 and 157/159 and the pumping cavity 153/154 within which they rotate and (b) relatively low pressure within the pump/motor 151/152, blood 17 leakage between the meshed teeth (known as slip and normal in varying degrees in pumps/motors) and any corresponding pressure drop is considered to be limited in this particular embodiment to an acceptable level without the need for either wear plates or additional fluid seals. Nonetheless, it is understood that whether in this and other embodiments, additional fluid sealing means such as to deposition of layer of resilient material on the surface of the inner rotor 156/158, outer rotor 157/159 and/or pumping cavity 153/154 may be employed if and when deemed to be necessary, preferable or beneficial noting that this would have no bearing on the operating principles of the apparatus and method of the present invention.

The operating principles and blood 17 flow for this embodiment were taught in the descriptions of previous figures including Fig’s 1 and 2 and so are not repeated again where instead the focus is on describing the structure and operation of this type of positive displacement pump 151 and motor 152 for the benefit of improved clarity.

Clearly, the same outcomes could be accomplished while remaining in accordance with the same operating principles and system flows by employing an embodiment with three rotors operating as set within the same cavity, as long as a stable volumetric displacement differential exists between the first and second acting as the pump and between the second and third acting as the motor.

Referring now to Fig. 22a, a more detailed view of the dual membrane blood filtration system taught in Fig. 12a is provided. More specifically, the generic representation of the blood pump module 90 (Fig. 12a) is replaced here with a more detailed view of a peristaltic type blood pump module 173 that represents just one of a plurality of positive displacement pumps 3a and/or hybrid motor/pumps 6a/3b and/or motor 6b types that may be employed interchangeably within this as well as various other single and multiple filter module systems.

In the case of this particular peristaltic pump module 173 design, the required volumetric displacement differential is achieved by employing the same I.D. peristaltic tubing in each of the pump 3a, hybrid motor/ pump 6a/3b and motor 6b elements, each of which have a progressively smaller rotor/roller swept radius such that their displacements are also progressively less being that their rotations are synchronized, whether that be because the rotors are driven by a shared driveshaft (hidden) or are a “triple stepped-down radii" single rotor 174 as seen here. In either case, they are driven by a single prime mover 25.

To ensure clarity however, we are first reminded that in the case of peristaltic pumps/motors their intake and discharge ports or conduits are actually aspects of the same tube but, for reasons of clarity in comparison they are expressed here, in the same manner as the other embodiments taught herein, that being identified separately.

Otherwise, just as with the generic blood pump module (90) of Fig. 12a, this blood pump module 173 comprises a larger displacement pump module 3a with an intake conduit 12 and a discharge conduit 13, a mid-displacement hybrid motor/pump module 6a/3b with an intake conduit 14 and a discharge conduit 93 and a smaller displacement motor module 6b with an intake conduit 94 and a discharge conduit 15 and wherein the pump module 3a feeds into the downstream hybrid motor/pump module 6a/3b which, in turn, feeds into the downstream motor module 6b such that an essentially stable volumetric displacement differentials exist between them.

It is also noted that because this is, in fact the filtration system previously taught in the description of Fig. 12a it is not re-taught here but for convenience of comparison and/or verification the element numbers are shown here in Fig.22a as well.

Referring first in general terms to Fig’s 22b to 22h, a plurality of other representative examples of positive displacement type blood pump modules are shown to further reinforce the principle that different positive displacement pump, motor or hybrid motor/pump types may be incorporated into the apparatus and method of the present invention in accordance with its key operating principles and novelty. As with the Fig. 12a and Fig.22a examples, each of these blood pump modules comprises a larger displacement pump module 3a connected to an intake conduit 12 and a discharge conduit 13, a mid-displacement hybrid motor/pump module 6a/3b connected to an intake conduit 14 and a discharge conduit 93 and a smaller displacement motor module 6b connected to an intake conduit 94 and a discharge conduit 15 and wherein the pump module 3a feeds into the downstream hybrid motor/pump module 6a/3b which, in turn, feeds into the downstream motor module 6b and also wherein these modules are driven synchronously by a shared driveshaft 9a or by another same acting synchronizing means such that a stable volumetric displacement differentials exist between them. Therefore, it is clear that they are interchangeable, whether for the blood filtration system taught in the descriptions of Fig’s 12a and 22a or, for that matter, for others embodiments.

More specifically, Fig.22b provides a front view of a second peristaltic type device, this one employing peristaltic tubing with different ID’s to provide the needed volumetric displacement differentials, Fig.22c provides a front view of a gerotor internal gear type device, as was taught in the descriptions of Fig.20 and Fig. 21 , Fig.22d provides a front view of an external gear type device, Fig. 22e provides a front view of a flexible belt impeller type device, Fig. 22f provides a front view of a balanced, sliding vane 175 impeller 176 type device, Fig.22g provides a front view of a flexible vane 177 type impeller 178 that could replace the impeller 176 of Fig.22f in some cases and Fig. 22h provides a front view of a sinusoidal or “sine” type device, noting that other types of positive displacement types may also be employed as long as they adhere to the same operating principles.

For reasons of clarity, arrows are shown linking the intake and discharge conduit identifying numbers in Fig.22d to remind that these pumps/motors employ continuous tubing elements that effectively combine their intake and discharge means, although it is again noted, that this has no impact on the operating principles of the apparatus and method of the present invention.

To summarize, all of the Fig. 22b to Fig.22h embodiments function according to the same operating principles and fluid flow paths that are based on progressively larger to smaller displacements, as was taught in the descriptions of Fig. 12a and Fig.22a. As can be seen, regardless of the physical differences in such features as their impellers, whether those be geared rotors, belt teeth, sinusoidal disks, occlusion rollers, vanes or, for that matter, some other fluid moving means, all of these blood pump modules incorporate a larger volumetric displacement pump module 3a, a mid volumetric displacement hybrid motor/ pump module 6a/3b and a smaller volumetric displacement motor module 6b feeding to each other in the above order and wherein all are connected without modification or the need for valves to the pump intake conduit 12 and discharge conduit 13, the hybrid motor/pump intake conduit 14 and discharge conduit 93 and the motor intake conduit 94 and discharge conduit 15 of the system taught in Fig’s 12a and 22a.

Referring now to Fig. 23, front view is provided of a valveless, rotary-reciprocating type device that incorporates a cooperating, larger volumetric displacement pump 3 and smaller volumetric displacement motor 6 set as previously taught in the descriptions of various embodiments such as those of Fig.2a and its minor variant Fig.2b. This single filter module system does not incorporate the hybrid motor/pump module 6a/3b taught in Fig’s 12a and 22a but otherwise functions in accordance with same operating principles. In this case the pump 3 and motor 6 chambers can each have the same volumetric displacements because the necessary volumetric displacement differential is provided for by independently adjusting the pump 3 and motor 6 stroke lengths by means of a conventional, dual head rotary- reciprocating type metering pump drive 179 that allows for the stroke length adjustments by changing the angle of the pump 3 and motor 6 module pistons in relation to the dual driveshafts 9 (hidden) located within the articulated couplers 180 and 161 of the pump drive 179.

It is noted that because this is in fact the filtration system that was previously taught in the description of Fig.2a and its minor variant Fig.2b. it is not re-taught here but for convenience of comparison and/or verification the element numbers of Fig.2a are re-shown here in Fig.23 as well.

Depending upon but not limited to such criteria as size limitations, application, torque and speed requirements and safety factors, a variety of prime mover types and styles, many being commonly available, may be employed to drive the various embodiments of the present invention described in this document. A number of these may employ or incorporate controllers for their own needs, it being understood that such use does not constitute a core requirement for or a necessary aspect of any of above embodiments the apparatus’ and method of the present invention.