[0001] Intermittent fluid pump

Field: [0002] The present disclosure relates to an apparatus that intermittently introduces a compressible fluid (gas) into an incompressible fluid (liquid) thereby converting potential energy into kinetic energy. The compressible fluid provides the force (pressure) to move the incompressible fluid for the purpose of intermittently pumping fluid comprising of a volume of gas and a volume of liquid. Background

[0003] Whenever a compressible fluid such as gas is introduced within an incompressible fluid such as liquid gas bubbles are formed.

[0004] Gas bubble forming devices can be used in various ways for different applications and typically function via the introduction of a continuous flow of gas directed into; 1 ) a vertical column having an open upper end and most often an open bottom end, these are typically termed as a static rube aerator; 2) a distribution manifold or diffuser comprising of orifices; 3) a venturi type fixture that functions with a continuous flow of pressurized liquid moving through a restriction generating a slight vacuum that can draw gas into the liquid thereby forming gas bubbles to be entrained within the liquid and released into the bulk liquid.

[0005] The gas bubbles once released into the liquid will change the density of the liquid within the area of discharge and thereby provide a means for generating a flow and or mixing the liquid. In addition gas can be distributed via a diffuser or a venturi fixture for transferring gas such as oxygen into the liquid as well as for mixing the liquid and its contents.

[0006] Prior art devices that operate with a continuous flow of gas for the purpose of pumping liquid via an 'airlift' process have a small lift capacity and suction or flow velocity as compared to mechanical pumping devices. Therefore, their use is limited to pumping liquid only vertically a short height above the liquid surface level. The limited suction or flow velocity can further lead to clogging problems, when continuous gas flow 'airlift' type pumps are applied within liquid containing particulates or sludge.

[0007] Improvements with respect to the continuous gas flow 'airlift' process employed for the purpose of pumping liquid and most specifically transferring a liquid out from a body of liquid have recently been introduced and are referenced below. [0008] U.S. Patent 6162020 by Masao Kondo discloses an airlift pump apparatus and method that injects air intermittently into a vertical riser.

[0009] U.S. Patent 8047808 by Masao Kondo discloses a 'geyser pump ¹ for vertically moving a liquid upward.

Summary

[0010] According to one aspect there is provided an intermittent fluid pump, which has a fluid storage housing. Fluid storage housing has a peripheral sidewall and a closed upper end defining an interior. A liquid influent opening is positioned at or near a bottom end. A gas intake is provided for introduction of gas into the interior of the storage housing such that gas accumulates at the closed upper end. A fluid transfer housing is positioned inside the fluid storage housing. The fluid transfer housing has an open upper end and a closed bottom end. A fluid conveyance conduit is provided having an upper discharge end and a lower end. A fluid transfer passage is positioned adjacent to the closed bottom end of the fluid transfer housing and provides for intermittent transfer of fluid into the lower end of the fluid conveyance conduit. . A liquid suction conduit is provided having an inlet end and an outlet end. The outlet end is positioned to direct liquid into the fluid conveyance conduit. As the intermittent fluid is transferred into the lower end of the fluid conveyance conduit, a density differential is created thereby generating an ascending flow that sucks liquid into the intake end of the liquid suction conduit.

[0011] A compressible fluid, such as gas, is introduced into a fluid storage housing containing an incompressible fluid, such as liquid, wherein the gas forces the liquid to flow downward into a fluid transfer housing positioned within the fluid storage housing. A fluid transfer passage directs liquid from the fluid transfer housing into a fluid conveyance conduit until the liquid is fully transferred at which point gas is transferred into the fluid conveyance conduit. As part of one embodiment the transferred gas generates a large gas bubble creating a density differential within the fluid conveyance conduit thereby providing a forceful ascending lift. The ascending lift sucks liquid into a liquid suction conduit such that liquid is directed into the fluid conveyance conduit. As liquid and gas are discharged from the fluid conveyance conduit liquid is introduced into the storage and transfer housings temporarily interrupting the transfer of gas whereby the intermittent cycling of fluid is established. [0012] The intermittent fluid pump can be incorporated within the field of wastewater treatment, as well as many other fields of application such as, but not limited to, aquaculture, vegetative wetlands, ponds and hydroponics.

[0013] The intermittent fluid pump can be operated independently, in combination with a fluid distribution manifold, a vertical oriented conveyance column, a gas diffuser, and or biofilm support media.

Brief description of drawings

[0014] These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:

[0015] FIG. 1 is a side elevation view, in section, illustrating an embodiment of the intermittent fluid pump and associative components. [0016] FIG. 2A is a side elevation view, in section, of an intermittent fluid pump in a first phase of operation.

[0017] FIG. 2B is a side elevation view, in section, of the intermittent fluid pump in a second phase of operation. [0018] FIG. 2C is a side elevation view, in section, of the intermittent fluid pump in a third phase of operation.

[0019] FIG. 2D is a side elevation view, in section, of the intermittent fluid pump in a fourth phase of operation.

[0020] FIG. 3 is a side elevation view, in section, illustrating an embodiment of the intermittent fluid pump incorporating a liquid flow controlling device, shown as dotted lines, incorporated into liquid influent opening of fluid storage housing and as an option illustrated with dotted lines, incorporated into a liquid input conduit. A fluid conveyance conduit passing through closed upper end of fluid storage housing, lower end of fluid conveyance is located within the fluid storage housing and positioned outside of a fluid transfer housing. Fluid transfer housing is in communication with fluid conveyance conduit via a fluid transfer passage positioned adjacent bottom end of the fluid transfer housing. A liquid suction conduit passes through lower end of fluid conveyance conduit.

[0021] FIG. 4 is a side elevation view, in section, illustrating an embodiment of intermittent fluid pump wherein the discharge end of fluid conveyance conduit is in communication with a distribution manifold. Fluid conveyance conduit is positioned outside of fluid storage housing and connected via a fluid transfer passage to fluid transfer housing that is located within fluid storage housing. A liquid suction conduit passes through lower end of fluid conveyance conduit. Also illustrated, with dotted lines, is the option of incorporating a liquid input conduit.

[0022] FIG. 5 is a side elevation view, in section, illustrating an embodiment of intermittent fluid pump incorporating a vertical oriented conveyance column positioned above the intermittent fluid pump and having the upper discharge end of fluid conveyance conduit positioned near bottom end of the vertical conveyance column and illustrating biofilm support media flowing into bottom end vertical conveyance column.

[0023] FIG. 6 illustrates a side elevation view, in section, of intermittent fluid pump incorporating a fluid distribution manifold in combination with biofilm support media and positioned above the biofilm support media.

[0024] FIG. 7 illustrates side elevation view, in section, of intermittent fluid pump incorporating a fluid distribution manifold in combination with biofilm support media positioned below the biofilm support media.

[0025] FIG. 8 illustrates a side elevation view, in section, of intermittent fluid pump in combination with movable biofilm support media, wherein in this embodiment the media is flowing into and out of the intermittent fluid pump.

Detailed description

[0026] Figure 1 illustrates an embodiment of the intermittent fluid pump 100 comprising of; gas intake 101, fluid storage housing 110 having a closed upper end 112, a bottom end 114 incorporating a liquid influent opening 116, fluid transfer housing 120 having an open upper end 122 a closed bottom end 124, fluid conveyance conduit 130 having an upper discharge end 132 and a lower end 134 and liquid suction conduit 140 having an inlet end 142 and an outlet end 144. [0027] Illustrated within this embodiment the fluid conveyance conduit 130 passes through upper closed end 112 of fluid storage housing 1 10 having lower end 134 positioned within fluid transfer housing 120 and near the closed bottom end 124 and in communication with fluid transfer passage 126, the upper discharge end 132 of fluid conveyance conduit 130 is positioned outside and above upper end 112 of fluid storage housing 110.

[0028] Liquid influent opening 1 16 is positioned, but not limited to, within the lower end 114 of fluid storage housing 110. [0029] Liquid suction conduit 140 having an inlet end 142 and an outlet end 144 passes through bottom end 124 of fluid transfer housing 120 having an outlet end 144 positioned within lower end 134 of fluid conveyance conduit 130 and above fluid transfer passage 126, inlet end 142 is positioned near to and above liquid influent opening 116.

[0030] As illustrated within this embodiment the outlet end 144 of liquid suction conduit 140 incorporates a cross-sectional dimension that is lesser than cross-sectional dimension of lower end 134 of fluid conveyance conduit 130.

[0031] The gas intake 101 as illustrated in figure 1 is not limited to the illustrated position at bottom end 124 of transfer housing 120 and additionally more than one gas intake can be incorporated into the intermittent fluid pump 100.

[0032] Figure 2A illustrates the first phase of operation of the intermittent fluid pump 200 when submerged within a body of liquid (not illustrated) wherein a gas is introduced into a fluid storage housing 210 via a gas intake 201 positioned at, but not limited too, bottom end 224 wherein gas generates gas bubbles 203 that ascend through liquid 207 contained within fluid storage housing 210 thereby generating a volume of gas 20S at the upper closed end of fluid storage housing 210.

[0033] As the volume of gas 205 expands downward, as indicated with doted directional arrows 206, it displaces the liquid 207 thereby forcing the liquid to flow downward, as indicated by solid directional arrows 208, out from bottom end 214 of the fluid storage housing 210 and simultaneously out of a fluid transfer housing 220 into a fluid conveyance conduit 230 via a fluid transfer passage 226.

[0034] Figure 2B illustrates the second phase of operation of the intermittent fluid pump 200 wherein the gas volume 205 has displaced the volume of liquid 207 within transfer housing 220 into fluid conveyance conduit 230, as indicated via doted arrows 206 wherein the gas volume 205 begins to enter fluid conveyance conduit 230 via fluid transfer passage 226 positioned adjacent to closed bottom end 224 of fluid transfer housing 220. [003S] The introduction of the transferred gas volume 205 into fluid conveyance conduit 230 creates a density differential wherein the volume of gas 205 begins to ascend within the fluid conveyance conduit 230 thereby forcing liquid 207 to discharge from discharge end 232 of fluid conveyance conduit 230 as indicated with solid arrow 208.

[0036] The density differential generated via the ascending gas 205 within fluid conveyance conduit 230 introduces liquid 207 into fluid storage housing 210, as indicated by arrows 208, via liquid influent opening 216. As the inflowing liquid 207 fills the fluid storage housing 210 and the fluid transfer housing 220 it forces remaining gas volume 205 into fluid conveyance conduit 230.

[0037] Figure 2C illustrates the third phase of operation of the intermittent fluid pump 200 wherein liquid volume 207 forces gas volume 205 to be transferred into fluid conveyance conduit 230, as indicated by solid arrow 208 wherein the density differential generated via ascending gas 205 sucks liquid into liquid suction conduit 240 via inlet end 242 wherein liquid 207 is discharged from outlet end 244 of liquid suction conduit 240.

[0038] The discharge of fluid from discharge end 232 of fluid conveyance conduit 230 enables the introduction of liquid 207 to flow into both fluid storage housing 210 and fluid transfer housing 220 thereby displacing the volume of gas 205 with the volume of liquid 207 temporally interrupting any further transfer of gas into fluid conveyance conduit 220 thereby establishing the intermittent cycling of fluid.

[0039] Figure 2D illustrates the fourth phase of operation of the intermittent fluid pump 200 having fluid storage housing 210 and fluid transfer housing 220 filled with liquid 207 wherein gas introduced into storage housing 210 via gas intake 201 ascends as gas bubbles 203 forming a volume of gas 205 at upper closed section 212 of fluid storage housing 210 thereby forcing liquid 207 to flow downward as indicated by solid arrow 208 thus beginning phase one of the intermittent fluid cycling process.

[0040] Figure 3 illustrates an embodiment of intermittent fluid pump 300 that functions under the same basic operational phases as described and illustrated with figures 2 A through 2D, wherein gas intake 301 passes through upper closed end 312 of fluid storage housing 310.

[0041] Liquid influent opening 316 incorporates a flow-controlling device 318-a. The flow-controlling device 318-a can be but not limited to a check valve or solenoid valve and be incorporated into liquid influent opening 316. As an alternative variant, illustrated with doted lines, a liquid input conduit 360 that directs liquid flow into liquid influent 315 can be equipped with a flow-controlling device 318-b.

[0042] Fluid storage housing 310 incorporates a fluid conveyance conduit 330 positioned outside of fluid transfer housing 320 and passing through upper closed end 312 of fluid storage housing 310.

[0043] Fluid transfer housing 320 is connected to fluid conveyance conduit 330 via fluid transfer passage 326 passing through sidewall near closed bottom end 324 of fluid transfer housing 320 and sidewall near lower end 334 of fluid conveyance conduit 330 wherein fluid transfer passage 326 transfers fluid from fluid transfer housing 320 into fluid conveyance conduit 330.

[0044] A liquid suction conduit 340 including an outlet end 344 and an inlet end 342 passes into lower end 334 of fluid conveyance conduit 330 wherein, in this embodiment, outlet end 344 is positioned above fluid transfer passage 324. Liquid suction 340 directs liquid into fluid conveyance conduit 330. [0045] The gas intake 301 as illustrated in figure 3 is not limited to the illustrated position at upper end 312 of fluid storage housing 310 and additionally more than one gas intake can be incorporated into the intermittent fluid pump 300.

[0046] Figure 4 illustrates another embodiment of intermittent fluid pump 400 that functions under the same basic operational phases as described and illustrated with figures 2A through 2D, wherein gas intake 401 passes through upper closed end 412 of fluid storage housing 410. [0047] Fluid transfer housing 420 housed within fluid storage housing 410 is connected to fluid transfer passage 426 adjacent to closed bottom end 424 of fluid transfer housing 420.

[0048] Fluid transfer passage 426 passes through sidewall of fluid storage housing 410 and sidewall near lower end 434 of fluid conveyance conduit 430. Fluid transfer passage 426 directs the intermittent slug of liquid and gas to be transferred from fluid transfer housing 420 into fluid conveyance conduit 430 that is positioned outside of fluid storage housing 410.

[0049] A liquid suction conduit 440 having an inlet end 442 and an outlet end 444 passes into lower end 434 of fluid conveyance conduit 430 wherein outlet end 444 is positioned near or equal to upper portion of fluid transfer passage 426.

[0050] As an option, illustrated within this embodiment and also possible with other embodiments, fluid conveyance conduit discharge end 432 is in communication with a fluid distribution manifold 450 incorporating orifices 452. [0051] Additionally as a variant illustrated within this embodiment and equally adapted to other embodiments of the intermittent fluid pump, is the ability to incorporate a liquid input conduit 460, illustrated with dotted lines, wherein liquid influent opening 416 and inlet end 442 of liquid suction conduit 440 can access liquid from liquid input conduit 460. [0052] The gas intake 401 as illustrated in figure 4 is not limited to the illustrated position at upper end 412 of fluid storage housing 410 and additionally more than one gas intake can be incorporated into the intermittent fluid pump 400.

[0053] Figure 5 illustrates another embodiment of intermittent fluid pump 500 that incorporates and operates in combination with a vertical oriented conveyance column 590 having an bottom end 592 and an upper end 594 and wherein the fluid conveyance conduit 530, but not limited too, being positioned partially into bottom end 592 of conveyance column 590. [0054] In operation the fluid conveyance conduit 530 discharges via upper discharge end 534 into vertical oriented conveyance column 590 thereby generating an ascending lift that draws liquid, liquid containing particulates, aggregates and or movable biofilm support media 560 as illustrated into bottom end 592 to be released at upper end 594. Upper end 594 cab fully submerged or above the liquid surface level

Figure 6 illustrates intermittent fluid pump 600 connected to a fluid distribution manifold 650 having orifices 652 placed along lower portion of fluid distribution manifold 650 and position above biofilm support media 670. [0055] In operation the intermittent discharge exiting the fluid distribution manifold orifices 652 provides a means of distributing a plurality of liquid streams (not illustrated) to be forced downward over and through biofilm media matrix 670 whereby the increased suction velocity of the intermittent fluid pump 600 enables the use of a distribution manifold 650 to distribute streams of liquid over a greater surface area. The force of the discharged liquid streams also provide a means to scrub or remove excess biofilm buildup from the biofilm support media 670 thereby enabling better flow through capacity and reduced maintenance.

Figure 7 illustrates intermittent fluid pump 700 connected to a fluid distribution manifold 750 having orifices 752 positioned along upper portion of fluid distribution manifold 750 and placed below submerged biofilm support media 780.

[0056] In operation the intermittent discharge exiting the fluid distribution manifold orifices 752 provides a method of distributing mixed diameter gas bubbles and liquid streams (not illustrated) that can flow up, and through submerged biofilm support media 780. This process allows the forced flow of gas bubbles and liquid streams to move across biofilm support media 780. The process described can provide a means to remove excess growth of biofilm thereby in certain applications maintain a desired flux throughput across a membrane, such as in membrane bioreactors.

[0057] Figure 8 illustrates an embodiment of the intermittent fluid pump 800 comprising of; gas intake 801, fluid storage housing 810 having a closed upper end 812 a bottom end 814, a slotted liquid influent opening 816 positioned near to bottom end 814, fluid transfer housing 820 having an open upper end 822 a closed bottom end 824, fluid conveyance conduit 830 having an upper discharge end 832 and a bottom end 834 and liquid suction conduit 840 having an a flared intake end 842 in communication with bottom end 814 and a flared outlet end 844.

[0058] The embodiment as described in figure 8 is to be practiced in combination with movable biofilm media. In operation intermittent pump 800 the intermittent transfer of liquid and gas into fluid conveyance conduit 830 generates an ascending forceful flow thereby allowing movable biofilm support media 860 to be sucked into flared inlet end 842 of liquid intake conduit 840 and discharged from liquid intake conduit flared outlet end 844 a distance above fluid transfer passage 824 into fluid conveyance conduit 830.

[0059] Liquid enters into liquid influent 816 of fluid storage housing 810 wherein liquid influent 816 incorporates slotted openings thereby preventing movable biofilm substratum 860 from entering into fluid storage housing 810. Alternatively the liquid influent 816 of fluid storage housing 810 can be connected to a separate liquid input conduit, as previously described and illustrated in figure 4, that draws liquid from a separate source.

[0060] The discharged biofilm media 860 can be circulated within the body of liquid (not illustrated) or be discharged so that the biofilm media 860 is discharged out of the body of liquid.

[0061] The embodiment described above is not limited to movable biofilm support media 860 flowing through the fluid conveyance conduit 830 it can alternatively be discharged into a vertical oriented conveyance via the operation of the intermittent pump promoting the flow of the movable biofilm support media into the vertical oriented conveyance column. In this option the intermittent pump can include liquid influent and fluid conveyance discharge end slots, screens or openings lesser than the size of the movable biofilm media thereby preventing movable biofilm media to flow into the intermittent fluid pump. [0062] The fluid mechanics of the intermittent fluid pump can provide for improvements over prior art by allowing the majority of the gas volume introduced within the housings to be transferred into the fluid conveyance conduit. This enables the formation of large volumetric gas bubbles that can displace an equal volume of liquid within the fluid conveyance conduit allowing an increased hydrodynamic density differential potential to develop thereby generating greater flow velocity and discharge height above a liquid surface level.

[0063] In operation the intermittent fluid pump provides a pulsating suction that is transferred to the body of liquid thereby allowing particles to move as tidal flow rather than strictly a unidirectional flow.

[0064] The height of the fluid conveyance conduit and the submergence depth of the intermittent pump determines the flow velocity.

[0065] The rate of gas flowing into the housings of the intermittent fluid pump and the fluid volumetric size of the housings governs the sequencing time of intermittent cycling and the volumetric flow of fluid per each cycle. Controlling the volume and the discharge flow rate via a controllable gas flow valve, or other controllable means, allows for greater energy efficiency, process functionality and mixing control. When incorporated in combination with movable biofilm support media the controllable rate of gas flow enables a method of customizing the throughput rate of the biofilm substratum into and out of the fluid conveyance conduit. This same controllable gas flow feature provides customized fluid flow throughput and bubble volume when the intermittent pump is operated in combination with other biofilm supported media types such as membrane bioreactors, membrane biofilm reactors or stationary biofilm support media. [0066] The introduction of a separate liquid suction conduit is a key component that differentiates over prior art. The liquid suction conduit can be custom designed to meet various bubble size requirements and fluid flow needs. The outlet end of the liquid suction conduit can be positioned proximal to lower end or partially housed within lower end of fluid conveyance conduit wherein the outlet end can be positioned above the fluid transfer passage. The liquid suction can be shaped to include flared ends or to form a venturi wherein fluid is allowed to accelerate after flowing passed a narrowing opening into a larger opening.

[0067] The positioning of the liquid suction conduit of the intermittent fluid pump can provide a straight unimpeded flow for liquid as well as for liquid comprising particulate matter, movable or granular type biofilm support media to freely move through the fluid conveyance conduit.

[0068] The use of a liquid input conduit can allow for a number of options. As for one example liquid can be introduced within the intermittent fluid pump that originates from a separate body of liquid than that of the liquid the intermittent pump is located within.

[0069] The incorporation of a liquid flow controlling device such as a check valve or solenoid valve incorporated within liquid influent opening, liquid suction conduit or within liquid input conduit provides support for controlling the input gas pressure and thereby providing lifting liquid to greater height or discharging fluid into a pressurized container. The feature of lifting liquid to greater height, as for one example, can be achieved by utilizing the volume of liquid within the fluid conveyance conduit that is above the volume of gas within the fluid conveyance conduit to determine the input gas pressure requirement for the flow of fluid.

[0070] In operation for an example within the field of wastewater treatment, the intermittent fluid pump can operate in combination with biofilm support media. The ability to form a large gas bubbles having a large suction wake can provide greater flow throughput, as for example across a membrane when used together with a membrane bioreactors or membrane biofilm reactors, by drawing off excessive biofilm growth buildup upon the membranes. When operated in combination with movable biofilm support media the intermittent fluid pump allows the circulation of the movable biofilm substratum to flow through the fluid conveyance conduit or alternatively to force the flow of the movable biofilm media into a vertical oriented conveyance column. [0071] In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

[0072] The scope of the claims should not be limited by the illustrated embodiments set forth as examples, but should be given the broadest interpretation consistent with a purposive construction of the claims in view of the description as a whole.