[0001] This application claims priority to U.S. Provisional Patent Application No. 61/983,984 filed April 24, 2014, and entitled MEASURING FLOW RATE, which is hereby incorporated by reference in its entirety as if set forth herein in full.

Backgrou nd

[0002] Having an accurate measure of flow rates may be important in a nu mber of chemical processes and systems, including for example, Cell Expansion Systems (CESs). CESs are used to expand different a nimal cells types, e.g., mesenchyma l stem cells, bone marrow, T cells. CESs utilize different fluids and the growth conditions of a CES may be affected by the flow rates of fluids within the system.

[0003] Embodiments have been made in light of these and other considerations. However, the relatively specific problems discu ssed a bove do not limit the applicability of the embodiments of the present disclosure.

Summary

[0004] The summary is provided to introduce aspects of some embodiments in a simplified form, and is not intended to identify key or essential elements, nor is it intended to limit the scope of the claims.

[0005] Embodiments relate to cell expansion systems (CESs) that may include a cell growth chamber and a flow rate mea suring system. The flow rate measuring system may include a weight measuring device adapted to weigh a container of fluid and a holding assembly adapted to connect the container of fluid to the weight measurement device. The CES may fu rther include at least one processor, wherein the at least on e processor is connected to the flow rate measuring system and may also include a pump connected to the at least one processor and configured to move the fluid from the conta in er into the cell growth chamber. [0006] Embodiments further relate to a flow rate measuring system that may include a holding assembly a nd at least one weight measuring device. Th e system may fu rther include a spacer attaching the hold ing assembly to the weight measuring device and a bea m attached to the at least one weight mea suring device a nd adapted to connect to a pole.

[0007] Additional embodiments may relate to a method of controlling fluid input into a cell expansion system. The method may include receiving, by a processor, an initial weight of a fluid for pumping into a cell expansion system. The processor may then receive a first pump rate, and a pump may be started at the first pump rate. The processor may then calculate an actual pu mp rate and determine that the actual pump rate differs from the first pump rate by more than a pred etermined amount. In response, the pump may be adjusted based on the determination made by the processor.

Brief Description of the Drawings

[0008] Non-limiting and non -exhaustive embodiments are described with reference to the following figures.

[0009] FIG. 1 illustrates a perspective view of a flow rate measuring system according to one embodiment.

[0010] FIG. 2 illustrates a front view of the flow rate mea suring system shown in FIG. 1.

[0011] FIG. 3 illustrates a front cross-sectional view of the flow rate measu ring system shown in FIGS. 1 and 2.

[0012] FIG. 4 illustrates a perspective view of a flow rate measuring system according to another embodiment.

[0013] FIGS. 5-12 illustrate a beam, at various stages of manufacturing, for use in a flow rate measuring system such as those illustrated in FIGS. 1-3.

[0014] FIGS. 13-16 illustrate a spacer, at various stages of manufacturing, for use in a flow rate measuring system such as those illustrated in FIGS. 1-3. [0015] FIGS. 17-20 illustrate an embodiment of assembling a flow rate measuring system a ccording to one embodiment.

[0016] FIG. 21 illustrates a block diagram of an embodiment of a cell expa nsion system that includes a flow rate measurement system a ccording to an embodiment.

[0017] FIG. 22 illustrates a schematic of a cell expansion system that may utilize a flow rate measuring system accord ing to an embodiment.

[0018] FIG. 23 illustrates an embod iment of a system that may in clude a flow rate measuring system accord ing to an embod iment.

[0019] FIG. 24 illustrates a flow chart showing a method of controlling flow of fluid into a cell expansion system a ccording to an embodiment.

[0020] FIG. 25 illustrates components of a computing system that may be used to implement embodiments.

Detailed Description

[0021] The principles of the present disclosure may be further understood by reference to the following detailed description and the embodiments d epicted in th e a ccompanying drawings. It should be understood that a lthough specific features are shown and described below with respect to detailed embodiments, the present disclosure is not limited to the embod iments described below.

[0022] Reference will now be made in detail to th e embodiments illustrated in the accompa nying drawings a nd described below. Wherever possible, the same reference numerals are used in the drawings and the description to refer to th e same or like parts.

[0023] FIGS. 1 and 2 illustrate d ifferent views of a flow rate measuring system 100 according to one embodiment. FIG. 3 illu strates a front cross-sectional view of the flow rate measuring system shown in FIGS. 1 and 2. In the embod iments shown in FIGS. 1-3, flow rate measuring system 100 includes a beam 104 that is adapted to be connected to a pole, such as pole 108, which in embodiments may be a bag pole commonly used for holding bags of fluids. In some embodiments, the bea m 104 may be referred to as a tolerance block. [0024] The beam 104 is connected to at least on e, e.g., in FIGS. 1-3 th ere is two, weight measuring devices. In system 100 the weight measuring device(s) are load cells 112A and 112 B. One example of load cells that may be used include an Omega LCEB-25 load cell manufactured by Omega Engineering, Stamford, CT. It is noted that other types of transducers (e.g., combinations of strain gauges) may be used in other embodiments in lieu of or in addition to load cells 112A and 112B.

[0025] In the illustrated embodiment, each load cell 112A and 112 B is connected to a spacer 116A and 116B respectively. The spacers 116A and 116B are used to connect the load cells 112A and 112B to a holding assembly 120.

[0026] The holding assembly 120 inclu des a number of features and is adapted to hold conta iners of flu id . For example, in some embod iments, assembly 120 may h old bags of fluid. In these embodiments, h ooks 124A and 124B may be used to hold one or more bags of fluid . In addition to hooks 124A and 124B, holding a ssembly 120 also includes two walls 128 and 132 that form a channel 136. As illustrated in FIGS. 1-3, spacers 116A and 116B are positioned, at least in part, within channel 136.

[0027] FIG. 3 illustrates a number of holes that are u sed to connect various features of system 100 togeth er. In embodiments, a number of different fa steners, some of which may be at least pa rtially positioned in the holes, may be used to conn ect the features together. Some non-limiting exa mples of fasteners that may be used include nuts, bolts, screws, washers, pins, an chors, rivets, fittings, etc.

[0028] As illustrated in FIG. 3, the load cells 112A and 112B experience th e load of any fluid in containers that are connected to assembly 120, because the spacers 116A a nd 116B are connected to the load cells 112A and 112B and the assembly 120. This allows load cells 112A and 112B to weigh fluid that is stored in containers that are connected to holding assembly 120.

[0029] FIG. 4 illustrates an embodiment of a flow rate measu ring system 200 according to embodiments. FIG. 4 illustrates some parts of system 200 in cluding a beam 204, weight measuring devices 222A and 222B, a holding assembly 220 for holding containers of fluid. In FIG. 4, holding assembly 220 is holding a bag 240 which contains a fluid. Flow rate measuring system 200 can be u sed to mea sure the flow rate of a fluid being removed from bag 240, as described in greater detail below.

[0030] FIGS. 5-12 illustrate a beam, at various stages of manufacturing, for use in a flow rate measuring system such as those illustrated in FIGS. 1-4. FIG. 5 illustrates a block 500 of material. In embodiments, block 500 may be made from a metal such a s aluminum. In one specific embodiment, block 500 may be made by first cutting about 8.70" of length from a section of aluminu m bar stock of d imen sions of a bout 1" x about 0.5". The cut section may then be faced with an endmill to obtain a ba r section measuring a bout 8.54" x about 0.938" x a bout 0.50" that may appear as shown in FIG. 5.

[0031] FIG. 6 illustrates block 500 with the addition of a through-h ole 504. The through-hole 504 may be created, in some embodiments, with a 3/4" ball end mill that cuts through the thickness of the block 500. The th rough-hole 504 may be centered on the bottom edge and bisect the longitude of block 500. In embodiments, a bout a ¼"-deep slot 508 may be cut into the same side of the ba r that may be about 1 ¼" long and also may be centered on the th rough-hole 504.

[0032] FIG. 7 illustrates block 500 (rotated 180 degrees from FIGS. 5 and 6) with the further ad dition of a second through -hole 512 (e.g., a chann el) along the length of block 500. The second through-hole 512 may be created with a 3/8" ball endmill, cutting along the length of block 500. The second through -hole 512 may be centered on th e bottom edge and bisect the thickness of block 500.

[0033] FIG. 8 illustrates block 500 (rotated back 180 degrees to same position a s shown in FIGS. 5 and 6) with the further addition of two chan nels 516A and 516B cut out to create arms 520A and 520B. In embodiments, channels 516A and 516B may be cut with a 1/8" end mill.

[0034] FIG. 9 illustrates block 500 with ad ditional through-holes 524A-D drilled into the arms 520A an d 520B. Through-holes 524A-C may be drilled, in some embodiments, using a size 36 clearance d rill. [0035] FIG. 10 illustrates block 500 with additional through-holes 528A and 528B d rilled into block 500. Through -hole 528A may be drilled, in some embodiments, using a 13/64" clearance drill. Through-hole 528B may be created using a 13/64" endmill.

[0036] FIG. 11 illustrates block 500 (rotated back 180 degrees to same position as shown in FIG. 7) with the addition of two countersink holes 532A and 532B that may be about 0.1" deep, in some embodiments. In embodiments, counter sink holes 532A and 532 B are created with a 19/64" endmill.

[0037] FIG. 12 illustrates block 500 with the add ition of threads in the through-holes 524A-D. In embodiments, the th reads may be created using a #6-32 hole ta p. In embod iments, a deburring tool and/or metal file may be used to d eburr edges.

[0038] FIGS. 13-16 illustrate a spacer, at various stages of manufacturing, for use in a flow rate measuring system such as those illustrated in FIGS. 1-4. FIG. 13 illustrates a block 1300 of material. In embodiments, block 1300 may be made from a meta l such as aluminum. In one specific embodiment, block 1300 is made by cutting about 1.1" of length from a section of a luminum bar stock with dimension of about 0.75" x about 0.75". In embod iments, the cut section may be faced with an endmill to obta in block 1300 that may have dimension of a bout 0.92" x about 0.550" x a bout 0.69".

[0039] FIG. 14 illustrates block 1300 with the addition of a chann el 1304 around a top portion of block 1300. In embod iments, channel 1304 may be made using an endmill. The channel may be a bout 0.19" deep from the top fa ce of the block 1300 in some embod iments.

[0040] FIG. 15 illustrates block 1300 with the addition of a hole 1308 in the center of block 1300. In embodiments, h ole 1308 may be made using a size 36 tap d rill, and made to be about 0.3"-deep. In some embodiments, hole 1308 may be threaded with a #6-32 hole tap.

[0041] FIG. 16 illustrates block 1300 with the addition of two through -holes 1312 and 1316, which in embodiments may be made using a size 29 tap drill. In embodiments through-holes 1312 and 1316 may be tapped with a #8-32 hole tap. In embodiments, a deburring tool and/or metal file may be u sed to deburr edges.

[0042] FIGS. 17-20 illustrate an embodiment of assembling a flow rate measuring system 2000. As shown in FIG. 17, fasteners 1700A and 1700B (which in embodiments may be #6-32 x 1" screws) are positioned through a hole in weight measuring devices 2012A and 2012B to connect them each to a spacer 2016A and 2016B respectively. In embodiments, spacers 2016A and 2016B may be manufa ctu red as described above with respect to FIGS. 13-16. The fasteners 1700A and 1700B may be hand tightened to the top hole of each spacer 2016A and 2016B, but with adequate room for a loose fit while ensuring that the threads are still engaged.

[0043] As shown in FIG. 18, a beam 1800 may be connected to the weight measuring devices 2012A and 2012B using fasteners 1804A, 1804B, 1804C, and 1804D (which in embod iments may be, for example, #6-32 x 1.25" screws). The beam 1800 may in embod iments be manufactu red as described above with respect to FIGS. 5-12. In embod iments, the weight measuring devices may be connected on either side of bea m 1800.

[0044] As shown in FIG . 18 each weight measuring device 2012A and 2012 B may be positioned within channels (1816A and 1816B) of beam 1800. For example, device 2012A may be positioned with in channel 1816A of beam 1800 and d evice 2012B may be positioned within cha nnel 1816B of bea m 1800. In embodiments, weight measuring devices 2012A and 2012B may be positioned equidistance from a center of beam 1800, which is indicated by line 1820. The position of weight measuring devices 2012A and 2012 B may be selected to balan ce side beam 1800.

[0045] FIG. 19 illustrates th e beam 1800 and weight measuring devices 2012A and 2012B connected to a t-junction on a pole 1900. The t-junction may be created by a cross member 1904. Beam 1800 may be connected to cross member 1904 u sing fa steners 1908A, 1908B, 1912A and 1912B. In one embodiment, fasteners 1908A and 1908B may be screws (e.g., #10-32 x 1.25" ) with fasteners 1912A and 1912B being nuts (e.g., #10-32 nuts). [0046] FIG. 20 illustrates a holding assembly 2020 connected to beam 1800 and weight measuring devices 2012A and 2012B. Th e holding assembly 2020 may be connected to the spacers 2016A and 2016B with fa steners 2020A and 2020B, which may be, e.g., #8-32 x 0.5" screws in one embodiment. In other embodiments, additional fasteners may be used.

[0047] In embod iments, hold ing assembly 2020 may include the same, or similar, features as holding assembly 120 described above with respect to FIG. 1. Holding assembly 2020 may includ e features configured to hold containers of fluid. For exa mple, in some embod iments, assembly 2020 may hold bags of flu id. In these embodiments, hooks 2024A and 2024B may be used to hold one or more bags of fluid. In some embodiments, hooks 2024A and 2024B are configured to slide back and forth along the length of the assembly 2020 as shown by arrow 2026 to adjust to the space between holes in a bag. This provides some flexibility on the types of bags that may be held by a ssembly 2020.

[0048] In addition to h ooks 2024A and 2024B, holding assembly 2020 includes two walls 2028 and 2032 that form a channel 2036. Spacers 2016A and 2016B may be positioned, at least in part, within channel 2036. Also, in some embod iments, cha nnel 2036 maybe used to hold a bag of flu id. For example, some bags may be held by a member (e.g., plastic member) that extends a long a length of a bag. In these embodiments, the member may be slid into channel 2036 through one end of assembly 2020. One or more ridges or lips (e.g., lip 2040) on walls 2028 and/or 2032 may hold the member in channel 2036. As illustrated in FIG. 20, lip 2040 is also within channel 2036. In embodiments, wa ll 2032 may have a corresponding lip that is opposite lip 2040. The lips together hold a member in channel 2036, which in turn holds a bag of liquid. One example of hold ing a bag of flu id that may include a member for holding the bag is illu strated in FIG. 4.

[0049] FIG. 21 illustrates a block diagram of an embodiment of a system 2100 that includes a flow rate measurement system 2104 according to an embodiment. As illustrated in FIG. 21, in addition to flow rate measurement system 2104, fluid delivery system 2104 may include a flu id source 2108, such as a bag of fluid, a pump 2112, and a processor/controller 2116. Furthermore, system 2100 may inclu de a fluid circulation system 2120 that in cludes various, flow path(s), growth cha mber(s), gas transfer modu le(s), pump(s), fluid source(s), va lve(s) etc. In one embodiment, a cell expansion system may comprise a part, or all of system 2120, includ ing various, flow path(s), growth cha mber(s), ga s transfer module(s), pump(s), fluid source(s), valve(s) etc. One embodiment of a cell expansion system is described below with respect to FIG. 22.

[0050] In embod iments, system 2100 provides for d elivering fluid as pa rt of a cell expansion system(s) at consistent and accurate rates. For example, fluid may be delivered into an intracapillary or an extracapilla ry flow path of a hollow fiber membrane (e.g., cell growth chamber) where cells are grown (see FIG. 22 and description below). In embod iments, pump 2112 may be controlled to provide fluid at actual flow rates that may be mainta ined with in about +/- 5 percent over flow rates that range from a bout 0.025 milliliters per minute (ml/min) to about 1500 ml/min . The a ctual flow rate may, in other embod iments, be ma intained within about +/- 5 percent over flow rates that range from about 0.1 ml/min to about 1000 ml/min. In yet other embodiments, the actual flow rate may be mainta ined within about +/- 5 percent over flow rates that range from about 0.1 ml/min to about 500 ml/min. Additionally, fluid volu mes delivered by pump 2112 may range from about 0.05 milliliters (ml) to about 2000 ml, su ch as about 0.1 ml to about 500 ml.

[0051] FIG. 22 illustrates a schematic of a cell expansion system (CES 600) that may be used with a flow rate measuring system (e.g., 100, 200, 2000, or 2104) according to an embod iment. In embodiments, CES 600 may comprise pa rt, or all, of a fluid circulation system, su ch as system 2120 (FIG. 21).

[0052] CES 600 in cludes a first fluid circulation path 602 (also referred to as the "intracapilla ry loop" or "IC loop" ) and second fluid circulation path 604 (also referred to as the "extracapillary loop" or "EC loop" ). First flu id flow path 606 may be flu idly associated with cell growth chamber 601 to form first fluid circulation path 602. Fluid flows into cell growth cha mber 601 through IC inlet port 601A, through hollow fibers in cell growth chamber 601, and exits via IC outlet port 601B. Pressure sensor 610 measures the pressure of media leaving cell growth chamber 601. In addition to pressure, sen sor 610 may, in embod iments, also be a temperature sensor that detects th e media pressure and temperature during operation. Media flows through IC circu lation pump 612 which may be used to control the rate of media flow. IC circulation pump 612 may pump the fluid in a first direction or second direction opposite the first direction. Exit port 601B may be used as an inlet in the reverse direction. Media entering the IC loop may enter through va lve 614. As those skilled in the art will appreciate, additional valves and/or other d evices may be placed at various locations to isolate and/or measure characteristics of the media along portions of the fluid paths. Accordingly, it is to be understood that the schematic shown represents one possible configuration for various elements of the CES 600, and modifications to the schematic shown are within the scope of the one or more present embodiments.

[0053] With rega rd to the IC loop, samples of media may be obtained from sample coil 618 during operation. Media then return s to IC inlet port 601A to complete fluid circulation path 602. Cells grown/expand ed in cell growth chamber 601 may be flu shed out of cell growth chamber 601 into harvest bag 699 th rough valve 698 and line 697. Alternatively, when va lve 698 is closed, the cells may be redistributed within chamber 601 for fu rther growth .

[0054] Fluid in second flu id circulation path 604 enters cell growth chamber 601 via EC inlet port 601C and leaves cell growth cha mber 601 via EC outlet port 601D. Media in the EC loop may be in contact with the outside of the hollow fibers in the cell growth chamber 601, thereby allowing d iffu sion of sma ll molecules into a nd out of the hollow fibers that may be within chamber 601, according to an embodiment.

[0055] Pressure/temperature sen sor 624 d isposed in th e second fluid circulation path 604 a llows the pressure and temperature of media to be measured before the media enters the EC space of the cell growth chamber 601. Sensor 626 allows the pressu re and/or temperature of media in the second fluid circulation path 604 to be mea sured after it leaves the cell growth chamber 601. With regard to the EC loop, samples of media may be obtained from sa mple port 630 or a sa mple coil during operation.

[0056] After leaving EC outlet port 601D of cell growth chamber 601, fluid in second fluid circulation path 604 passes through EC circulation pump 628 to oxygenator or gas transfer mod ule 632. EC circu lation pump 628 may also pump the fluid in opposing direction s, according to embodiments. Second fluid flow path 622 may be fluidly associated with oxygenator or gas transfer modu le 632 via an inlet port 632A and an outlet port 632B of oxygenator or gas transfer module 632. In operation, fluid med ia flows into oxygenator or gas transfer module 632 via in let port 632A, and exits oxygenator or gas transfer module 632 via outlet port 632B. Oxygenator or gas transfer module 632 adds oxygen to and removes bu bbles from media in the CES 600. In various embodiments, media in second fluid circulation path 604 may be in equilibrium with gas entering oxygenator or gas transfer module 632. Th e oxygenator or ga s transfer modu le 632 may be any appropriately sized device u seful for oxygenation or gas transfer. Air or gas flows into oxygenator or gas transfer module 632 via filter 638 and out of oxygenator or ga s transfer device 632 through filter 640. Filters 638 and 640 reduce or prevent contamination of oxygenator or gas transfer module 632 and associated media . Air or gas purged from the CES 600 during portions of a priming sequence may vent to the atmosphere via the oxygenator or gas transfer module 632.

[0057] In the configuration depicted for CES 600, fluid media in first fluid circulation path 602 and secon d fluid circulation path 604 flows through cell growth chamber 601 in the same direction (a co-current configuration). The CES 600 may also be configured to flow in a counter-current conformation, according to embodiments.

[0058] In accordance with at least one embodiment, media, including cells (from a source such as a cell container, e.g. a bag) may be attached at attachment point 662, and fluid media from a media source may be attached at attach ment point 646. The cells and media may be introduced into first fluid circulation path 602 via first fluid flow path 606. Attachment point 662 may be fluidly associated with the first flu id flow path 606 via valve 664, and attachment point 646 may be fluidly associated with the first fluid flow path 606 via valve 650. A reagent source may be flu idly connected to point 644 and be associated with fluid inlet path 642 via va lve 648, or second flu id inlet path 674 via valves 648 and 672.

[0059] Air removal chamber (ARC) 656 may be fluid ly associated with first circulation path 602. The air removal chamber 656 may include one or more sensors including an upper sensor and lower sensor to detect air, a lack of fluid, and/or a gas/fluid interface, e.g., an air/fluid interface, at certain measu ring positions within the air removal chamber 656. For example, ultrason ic sensors may be u sed near the bottom and/or near the top of the air removal chamber 656 to detect a ir, fluid, and/or an air/fluid interface at these locations. Embodiments provide for the use of n umerous other types of sensors without departing from the spirit and scope of the present disclosure. For example, optical sensors may be used in a ccordance with embod iments of the present disclosure. Air or ga s purged from the CES 600 during portions of a priming sequ ence or other protocol(s) may vent to the atmosphere out air valve 660 via line 658 that may be fluidly associated with air removal chamber 656.

[0060] An EC media source may be attached to EC media attachment point 668 and a wash solution source may be attached to wash solution attachment point 666, to add EC media and/or wash solution to either the first or second fluid flow path . Attachment point 666 may be flu idly associated with valve 670 that may be fluidly associated with first flu id circulation path 602 via valve 672 and first fluid inlet path 642. Alternatively, attachment point 666 may be fluidly a ssociated with second fluid circulation path 604 via secon d flu id inlet path 674 by opening valve 670 and closing valve 672. Likewise, attachment point 668 may be fluidly associated with valve 676 that may be fluidly associated with first flu id circulation path 602 via first fluid inlet path 642 and valve 672. Alternatively, fluid container 668 may be fluidly associated with second fluid inlet path 674 by opening valve 676 and closing valve distribution 672.

[0061] In the IC loop, fluid may be initially advan ced by the IC inlet pump 654. In the EC loop, fluid may be initially advanced by the EC inlet pu mp 678. An air detector 680, such as an ultrasonic sen sor, may also be associated with the second fluid inlet path 674.

[0062] In some embodiments, pumps 654 and 678 may be connected to one or more fluid flow rate measuring system(s) (e.g., system 100, 200, 2000, and/or 2104) and one or more processors for controlling the speed of the pu mps. For example, embodiments may provide for one or more fluid flow measuring system(s) at each of attachment points 662, 644, 646, 666, and 668. The fluid flow measuring system(s) may be connected to a processor that is also connected to pumps 654 and 678. The processor may take information from fluid flow mea suring system and determine fluid flow rates, which may result in changing of pump speeds of pu mps 654 and 678. [0063] In at least one embodiment, first and second fluid circulation paths 602 and 604 are connected to waste line 688. When va lve 690 is opened, IC media may flow through waste line 688 and to wa ste or outlet bag 686. Likewise, when valve 692 is open ed, EC media may flow to waste or outlet bag 686.

[0064] After cells have been grown in cell growth chamber 601, they may be harvested via cell ha rvest path 697. Here, cells from cell growth chamber 601 may be harvested by pumping the IC media containing the cells through cell harvest path 697, with valve 698 open, into cell harvest bag 699. Various components of the CES 600 may be contained or hou sed within a mach ine or hou sing, such as a cell expa nsion machine 2304 (FIG. 23) described below, wherein the machine maintain s cells and media at a predetermined temperature.

[0065] FIG. 23 illustrates a system 2300 that includes a cell expansion machine 2304 and at least one flow rate measuring system 2312. In embodiments, cell expan sion machine 2304 houses components of a cell expansion system, such as the components of CES 600 described with respect to FIG. 22. Machine 2304 in embodiments, maintain s components of a cell expansion system at a controlled temperatu re.

[0066] Machine 2304 may also include, inter alia, a computer system including one or more processors for controlling operation of the system 2300 and receiving information from flow rate measuring system 2312. Machine 2304 may also include input/output devices connected to the computer system, such as tou ch sensitive display 2308 for interfacing with an operator.

[0067] FIG. 24 illustrates flow 2400 that may be performed in embodiments to control fluid input into a system such a s a cell expansion system. Although specific devices may be described below for performing steps in flow 2400, embodiments a re not limited thereto. For exa mple, some steps may be described a s performed by a processor, which may execute steps based on software provided as processor executable in structions. This is done merely for illustrative purposes, and flow 2400 is not limited to being performed by any specific device. [0068] Flow 2400 starts at step 2404 and proceed s to step 2408 where a n initial weight of flu id is received. In embodiments, a processor may receive the initia l weight from a weighing device that may be part of a flow rate measuring system, such as a load cell or weight measuring device (e.g., 112A, 112B, 2012A, and 2012B).

[0069] In some embodiments, step 2404 may be preceded by some calibration steps. As one example, the weighing device may be zeroed. That is, the weighing device may be set to zero, prior to any fluid being connected to the weighing device.

[0070] Flow 2400 proceeds from step 2408 to step 2412 where a first rate for a pu mp may be received. The first rate may be in some embodiments received by a processor from an operator. For example, an operator may utilize a touch sensitive display for entering the first rate.

[0071] From step 2412, flow 2400 pa sses to 2416 where a pump is started at a first rate. After step 2416 a d etermination is made at 2420 as to whether the circulation of fluid is done becau se for exa mple a predetermined time period has passed or a particular volu me of fluid ha s been pumped. In embodiments, flow 2400 may be used d uring the pumping of a predetermined volume of fluid, which may range from about 0.05 ml to about 2000 ml, such as about 0.1 ml to a bout 500 ml. If a determination is made at 2420 that the circulation is don e, flow 2400 ends at 2444.

[0072] If a determination is made at 2420 that the fluid circulation is not done, flow 2400 passes to step 2428 where a current weight of the fluid is received. As described above, in embod iments a processor may receive the current weight from a weighing device that may be pa rt of a flow rate mea suring system, such as a load cell (e.g., load cells 112A, 112 B, 2012A, and 2012B).

[0073] At step 2432, the actual flow rate is calculated. As may be appreciated, step 2432 may involve a number of sub-steps, such as determining the changes from the initial weight to the current weight an d determining a period of time that has passed between steps 2416 and 2428. In determining the actual flow rate at step 2432, the density of the fluid may also be used. [0074] Step 2432 may involve th e use of various algorithms to determine th e a ctual flow rates. In one embodiment, the density of the fluid may be previously known. For example, if the solution comprises water, it may have a density of a bout 1 gram per liter (g/l). Step 2432 may therefore involve u sing the current weight received at step 2428 and su btracting the current weight from a previous weight to determine the weight of flu id that has been delivered in the period of time, wh ich is recorded and/or calculated. Using the su btracted weight and the known den sity of the volume of fluid delivered during the period of time may be determined. A flow rate can then be determined by using the volume and the length of the period of time.

[0075] After step 2432, a determination is made at 2436 whether th e actual flow rate is within some predetermined acceptable difference of the first flow rate. The predetermined acceptable difference may be some predetermined value, some non-limiting examples including, +/- 0.025 milliliters per minute (ml/min), +/- 0.05 ml/min, +/- 1-0 ml/min, +/- 2 ml/min, +/- 3 ml/min, +/- 4 ml/min, or even +/- 5 ml/min. Alternatively, the predetermined acceptable difference may be a percentage such as about +/- 5 percent, about +/- 4 percent, about +/- 3 percent, or even a bout +/- 1 percent.

[0076] If a determination is made at 2436 that the actual flow rate is within the predetermined accepta ble d ifference, flow 2400 passes back to 2420. If a determination is made at 2436 that the actual flow rate is not within the predetermin ed acceptable difference, flow passes to step 2440 where the first pu mp rate is adjusted . Depending on whether the actua l pump rate calculated at 2432 is higher or lower than the first pump rate, the pump rate may be reduced or increased.

[0077] After the pump is adju sted at step 2440, flow 2400 passes back to 2420. If at 2420 a determination is made that the fluid circulation is not done, flow 2400 proceeds through steps 2428, 2432, 2436, and 2440. In embodiments, these steps provide for mainta in ing the actua l flow rate (by controlling the speed of a pump) to within a predetermined difference of a set flow rate, i.e., the rate received at step 2412. That is, steps 2428, 2432, 2436, and 2440 are performed to maintain the actua l flow rate at a rate received at step 2412. In embodiments, the actual flow rate may be ma intained within at least about +/- 5 percent over flow rates that range from a bout 0.025 milliliters per minute (ml/min) to about 1500 ml/min . The actua l flow rate may, in oth er embodiments, be mainta in ed within at lea st about +/- 5 percent over flow rates that range from about 0.1 ml/min to about 1000 ml/min . In yet other embodiments, the actua l flow rate may be mainta in ed within at lea st about +/- 5 percent over flow rates that range from about 0.1 ml/min to about 500 ml/min .

[0078] In other embodiments, the actual flow rate may be mainta ined within a bout +/- 5 percent of a flow rate that may be about 0.1 milliliters per minute (ml/min), that may be about 1 ml/min, that may be a bout 8 ml/min, that may be about 10 ml/min, that may be about 50 ml/min, that may be about 100 ml/min, that may be about 150 ml/min, that may be about 200 ml/min, that may be about 350 ml/min, or that may be about 500 ml/min.

[0079] Referring back to FIG. 24, if at decision 2420 a determination is made that the fluid circulation is don e, flow 2400 ends at 2444.

[0080] FIG. 25 illustrates example components of a basic computer system 2500 upon which embodiments may be implemented. Computer system 2500 includes output device(s) 2504, a nd input device(s) 2508. Output device(s) 2504 may include, among other things, one or more displays, including CRT, LCD, and/or plasma displays. Output device(s) 2504 may a lso include printers, spea kers etc. Input device(s) 2508 may in clude, without limitation, a keyboard, touch input devices, a mouse, voice input device, scanners, etc. Computer system 2500 may include devices that are both input/output d evices such as touch sensitive displays.

[0081] Basic computer system 2500 may also include one or more processor(s) 2512 and memory 2516, accord ing to embodiments of the present invention. In embodiments, the processor(s) 2512 may be a general purpose processor(s) opera ble to execute processor executable in structions stored in memory 2516. Processor(s) 2512 may include a single processor or multiple processors, a ccording to embodiments. Further, in embodiments, ea ch processor may be a single core or a multi-core processor, having one or more cores to read and execute separate instructions. The processor(s) 2512 may include, in embod iments, general purpose processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and other integrated circuits. [0082] The memory 2516 may include any tangible storage medium for sh ort-term or long-term storage of data and/or processor executa ble instructions. The memory 2516 may include, for exa mple, Random Access Memory (RAM ), Read-Only Memory (ROM ), or Electrically Erasa ble Programmable Read-Only Memory (EE PROM ). Other storage med ia may in clude, for exa mple, CD-ROM, tape, digital versatile disks (DVD) or other optical storage, tape, magnetic disk storage, magnetic tape, other magnetic storage devices, etc.

[0083] Storage 2528 may be any long-term data storage device or component. Storage 2528 may include one or more of the devices described a bove with respect to memory 2516. Storage 2528 may be permanent or removable.

[0084] Computer system 2500 a lso includes communication devices 2536. Devices 2536 allow system 2500 to communicate over networks, e.g., wide area networks, local area networks, storage area networks, etc., and may include a number of devices such as modems, hubs, network interfa ce ca rds, wireless network interface cards, routers, switches, bridges, gateways, wireless access points, etc.

[0085] The components of computer system 2500 a re shown in FIG. 25 a s con nected by system bus 2540. It is noted, however, that in other embodiments, the components of system 2500 may be con nected using more than a single bu s. In embodiments, 2116 (FIG. 21) or system 2300 (FIG. 23) may include aspects of computer system 2500.

[0086] It will be apparent to those skilled in the art that various modifications and va riation s can be made to the methods and structure of the present invention without departing from its scope. Thus it should be understood that the invention is not be limited to the specific examples given . Rath er, the invention is intended to cover modifications and va riation s within the scope of the following claims and their equivalents.

[0087] While example embodiments and applications of the present invention have been illustrated and d escribed, it is to be understood that the invention is not limited to the precise configu ration and resources described above. Various modifications, changes, and va riation s appa rent to those skilled in the art may be made in the arrangement, operation, and details of the method s and systems of the present invention disclosed herein without departing from the scope of the present invention.