EP2855934A1

EP2855934A1 - Multi-chamber pump apparatus, systems, and methods

Info

Publication number: EP2855934A1
Application number: EP13782364.7A
Authority: EP
Inventors: Tomasz MOSKAL; Robert Autrey
Original assignee: Siemens Healthcare Diagnostics Inc
Current assignee: Siemens Healthcare Diagnostics Inc
Priority date: 2012-04-23
Filing date: 2013-04-19
Publication date: 2015-04-08
Also published as: US20150086386A1; WO2013163033A1; EP2855934A4

Abstract

Disclosed are apparatus adapted to dispense and/or aspirate liquids, such as in a clinical analyzer. In one aspect, a multi-chamber pump apparatus is disclosed that has a pump body containing first and second chambers, a piston having a first piston portion of a first pump area Al received in the first chamber, and a second piston portion of a second pumping area A2 received in the second chamber, and an actuator coupled to the piston. The first and second chambers can be selectively accessed to improve metering accuracy at dissimilar flow volumes from the chambers. Methods and systems including the multi-chamber pump apparatus are provided, as are other aspects.

Description

MULTI-CHAMBER PUMP APPARATUS, SYSTEMS, AND METHODS

FIELD

[0001] The present invention relates generally to apparatus, systems, and methods adapted to aspirate and dispense liquids.

BACKGROUND

[0002] In automated medical specimen testing, biological fluid specimens, reagents, wash liquids, and purified water may be aspirated and/or dispensed for various purposes. For example, in some automated testing systems (e.g., clinical analyzer instruments), biological fluid specimens (e.g., blood, blood plasma, interstitial fluid, spinal fluid, urine, or the like) contained in sample containers (such as test tubes, sample cups, vials, cuvettes, and the like) may be tested to determine a presence of an analyte, other identifiable substance, or a characteristic thereof. As part of this process, metering (pumping) of the biological fluid, reagent, and/or purified water may be desired. In order to provide for testing accuracy, the metering of such fluids should, in some instances, be very precise.

[0003] For example, in some testing methods, such as the so- called "chase method, " a relatively smaller volume of biological fluid is first aspirated and dispensed by a metering apparatus, and the dispensing of this biological fluid is followed (chased) by dispensing a relatively larger volume of purified water. In the chase method, the volume of dispensed process fluid may be greater than the volume of the biological fluid that is dispensed. In a so-called "neat method," a small amount of biological fluid is aspirated and dispensed (on the order of 1-3 pL) . In the neat method, the purified water may only be the transport vehicle (i.e., a liquid backing in the conduit) that allows for the metering of the biological fluid, even though the purified water may not itself be dispensed. In other words, the purified water acts as the backing that enabling the aspiration and dispensing of the biological fluid. However, for both methods, it should be understood that inaccurate metering may lead to less accurate specimen testing results.

[ 0004 ] Additionally, as part of washing probes, sometimes relatively larger volumes of water (e.g. purified water) may be dispensed. This may be dispensed by a probe or into a receptacle (e.g., washing/drain system) that is used to wash the probe. Wash liquid containing detergents may also be dispensed .

[ 0005 ] In prior art systems, separate pumps have been utilized to accomplish precise metering at both relatively lower volumes and the relatively larger volumes. Accordingly, apparatus, systems, and methods that may improve fluid dispensing/aspiration are desired.

SUMMARY

[0006] According to a first aspect, a multi-chamber pump apparatus is provided. The multi-chamber pump apparatus includes a pump body containing a first chamber and a second chamber, each adapted to contain a liquid, a piston having a first piston portion of a first pump area Al received in the first chamber, and a second piston portion of a second pumping area A2 received in the second chamber, and an actuator coupled to the piston.

[0007] In a system aspect, a liquid delivery system is provided. The liquid delivery system includes at least one liquid source, a multi-chamber pump apparatus fluidly coupled to the at least one liquid source, the multi-chamber pump apparatus having a pump body with a first chamber and a second chamber, a piston having a first piston portion of a first pump area Al received in the first chamber, and a second piston portion of a second pumping area A2 received in the second chamber, a dispensing and/or aspirating device fluidly coupled to a first chamber outlet of the first chamber, and a second chamber outlet of the second chamber, a first flow- controllable passage fluidly coupled to the first chamber; and a second flow-controllable passage fluidly coupled to the second chamber.

[0008] In a method aspect, an improved liquid delivery method is provided. The method includes providing at least one liquid source containing a liquid, providing a multi-chamber pump apparatus fluidly coupled to the at least one liquid source, the multi-chamber pump apparatus having a pump body with a first chamber and a second chamber, a piston having a first piston portion of a first pump area Al received in the first chamber, and a second piston portion of a second pumping area A2 received in the second chamber, providing a dispensing and/or aspirating device fluidly coupled to a first chamber outlet of the first chamber, and a second chamber outlet of the second chamber, and translating the piston to pump liquid to the dispensing and/or aspirating device.

[ 0009 ] Still other aspects, features, and advantages of the present invention may be readily apparent from the following detailed description by illustrating a number of exemplary embodiments and implementations, including the best mode contemplated for carrying out the present invention. The present invention may also be capable of other and different embodiments, and its several details may be modified in various respects, all without departing from the scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. The drawings are not necessarily drawn to scale. The invention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 illustrates an isometric view of an example liquid metering system according to the Prior Art.

[0011] FIG. 2A illustrates an isometric view of a multi- chamber pump apparatus according to embodiments.

[0012] FIG. 2B illustrates a cross-sectioned side view of a multi-chamber pump apparatus according to embodiments.

[0013] FIG. 2C illustrates an end view of a first piston portion (shown hatched) of a multi-chamber pump apparatus according to embodiments.

[0014] FIG. 2D illustrates an end view of a second piston portion (shown hatched) of a multi-chamber pump apparatus according to embodiments.

[0015] FIG. 2E illustrates an isometric view of a piston of a multi-chamber pump apparatus according to embodiments.

[0016] FIG. 2F illustrates an isometric view of a coupling of a multi-chamber pump apparatus according to embodiments.

[0017] FIG. 2G illustrates an isometric view of a lower pump housing of a multi-chamber pump apparatus according to embodiments .

[0018] FIG. 2H illustrates an isometric view of a middle pump housing of a multi-chamber pump apparatus according to embodiments .

[0019] FIG. 21 illustrates an isometric view of an upper pump housing of a multi-chamber pump apparatus according to embodiments . [ 0020 ] FIG. 2J illustrates an isometric view of a pump motor of a multi-chamber pump apparatus according to embodiments.

[ 0021 ] FIG. 2K illustrates an isometric view of a sensor of a multi-chamber pump apparatus according to embodiments.

[ 0022 ] FIG. 3A illustrates a block diagram view of a liquid dispensing system including a multi-chamber pump apparatus according to embodiments.

[ 0023 ] FIG. 3B illustrates a block diagram view of another liquid dispensing system including the multi-chamber pump apparatus according to embodiments.

[ 0024 ] FIG. 3C illustrates a block diagram view of another liquid dispensing system including the multi-chamber pump apparatus according to embodiments.

[ 0025 ] FIG. 4 is a flowchart illustrating a liquid delivery method of according to embodiments

DETAILED DESCRIPTION

[0026] In current liquid dispensing and aspirating systems, achieving precision in the metering of both a relatively large volumes of fluid such as in the "chase" method, and relative low volumes of fluid such as in the "neat" method, provides a significant challenge. This is because pumps, in general, become inefficient and quite inaccurate when dispensing fluid at less than about 20% of their intended stroke. In order to provide sufficient accuracy for both relatively high volume aspiration and/or dispense operations and also for relatively low volume aspiration and/or dispense operations, multiple pumps are used in prior art systems . In particular, one pump may be designed to obtain accuracy for the relatively lower dispense/aspirate volumes, and the other is designed to achieve accuracy at relatively higher volume dispense/aspiration volumes. However, utilizing multiple pumps may result in unwanted system expense and complexity.

[0027] As shown in FIG. 1, a prior art liquid dispense/aspiration system 100 is shown. The system 100 includes a feed tank 102, which provides a supply of liquid, such as purified water or saline buffer, for example, to a fluid metering apparatus 104 including a first metering pump 106, a second metering pump 108, valves 110, a distribution manifold 112, a delivery line 114, and a probe 116. The metering line 114 fluidly couples the probe 116 to the metering apparatus 104 and allows both aspirating and dispensing of liquids. The feed tank 102 may be filled directly from a purification system (not shown) , which receives its inflow of water directly from a water supply (not shown) .

[ 0028 ] Accordingly, an improved system and pump capable of achieving both relatively precise high volume aspiration and/or dispense operations, and relatively precise low volume aspiration and/or dispense operations is desired. To solve the above-identified problems, a multi-chamber pump apparatus is provided. In some instances, such as those where the metered volume of the fluid is relatively small (such as in the above- mentioned "neat" method), the pump may dispense and/or aspirate utilizing a first chamber, whereas for relatively larger dispense and/or aspiration operations, a second chamber may be used. A single drive motor may be used to drive a piston operable in both the first and second chambers.

[ 0029 ] These and other aspects and features of the invention will be described with reference to FIGs. 2A-4 herein.

[ 0030 ] In accordance with a first embodiment of the invention, as best shown in FIG. 2A-2B, a multi-chamber pump apparatus 200 is described. The multi-chamber pump apparatus 200 may be coupled to, or be part of, a liquid metering system 300A-300C of an instrument as is shown in FIG. 3A through FIG. 3C, for example. The instrument may be a clinical analyzer or other instrument adapted to aspirate and/or dispense biological fluids, reagents and/or other liquids as part of testing the biological fluids. The multi-chamber pump apparatus 200 may be provided in other systems in which precisely-controlled liquid aspiration and/or dispense operations are carried out.

[ 0031 ] The multi-chamber pump apparatus 200 comprises a pump body 220 having a first chamber 222 and a second chamber 224, each adapted to contain a liquid to be aspirated or dispensed. The liquid may be biological fluid, reagent, water (e.g., purified water), wash solution, liquid detergent, or the like. The multi-chamber pump apparatus 200 also includes a piston 226 (See FIG. 2E) . The piston 226 is a translating member that translates within the pump body 220 and has a first piston portion 226L of a first diameter Dl (FIG. 2E) and a first pumping area Al (FIG. 2C - shown hatched) received in the first chamber 222, and a second piston portion 226U of a second diameter D2 (FIG. 2E) and a second pumping area A2 (FIG. 2D - shown hatched) received in the second chamber 224. Generally, the piston 226 may include concentric cylinders, wherein Dl > D2.

[ 0032 ] In the depicted embodiment, the first pumping area Al is an annulus, whereas the second pumping area A2 is a circle. In the depicted embodiment, Dl > D2. The first diameter Dl may be between about 0.188 in (4.78 mm) and about 1.50 in (38.1 mm), and about 0.403 in (10.2 mm) in the depicted embodiment. The first pumping area Al may be between about 0.0023 in² (1.484 mm²) and about 1.735 in² (1119.0 mm²) and about 0.017 in² (11.0 mm²) in the depicted embodiment. The second diameter D2 may be between about 0.180 in (4.57 mm) and about 2.00 in (50.8 mm), and about 0.375 in (8.89 mm) for the depicted embodiment . The second pumping area A2 may be between about 0.025 in² (16.4 mm²) and about 3.14 in² (2030 mm²), and about 0.110 in² (71.2 mm²) in the depicted embodiment. In particular, A2 > Al, and in some embodiments A2 > 3A1, and in some embodiments A2 > 5A1, and even in some embodiments A2 > 8A1. The piston portions 226U, 226L may be formed as part of a stepped-diameter piston 226 including a first shaft sealing portion 227L and a second shaft sealing portion 227U that seal with lower and upper seals 227SL, 227SU, respectively. The first shaft sealing portion 227L and a second shaft sealing portion 227U may be co-axial. In some embodiments, the piston 226 may be a precision-ground ceramic material, such as 95% zirconia. Other materials may be used.

[ 0033 ] The multi-chamber pump apparatus 200 includes an actuator 228 coupled to the piston 226. The actuator 228 may be a stepper motor such as shown in FIG. 2J, whereas rotation of the stepper motor results in precise linear motion of a shaft 228S of the actuator 228, and, thus, translational motion of the piston portions 227U, 227L in first and second chambers 222, 224. Optionally, the actuator 228 may be a pneumatic actuator, servo-actuator, or the like. Other suitable motors to impart linear motion may be used.

[ 0034 ] The actuator 228 may be coupled to the piston 226 by any suitable means, such as a coupling 230. Any suitable coupling 230 may be used. For example, the piston 226 may be attached to the coupling 230 by being adhesively bonded an end thereof into a pocket 230P formed in the coupling (See FIG. 2F) . The shaft 228S of the actuator 228 may be attached to the coupling 230 by a suitable fastener 232, such as a set screw, received in a threaded hole 233 (FIG. 2F) or other suitable mechanical connection. The coupling 230 may have a flag 230F extending from a mean body of the coupling 230 that is configured and adapted to interface with a sensor 234. The sensor 234 may be mounted to the pump body 220 such as by screws or the like, and the flag 230F may be configured to interact with the sensor 234 to provide information concerning an axial position of the piston 226 along its stroke.

[ 0035 ] The sensor 234 may be any suitable type of sensor, for example. The sensor 234 may sense an uppermost axial dispense excursion of the piston 226 of the pump apparatus 200. For example, the sensor 234 may be a light sensor having a light beam that when broken produces a changed signal output . The interaction with the sensor 234 may involve the light beam being broken by the flag 230F passing between a light generator and a light receiver housed in legs 234A, 234B of the sensor 234 (See FIG. 2K) . The breaking of the light beam may signify that a maximum dispense location of the pump 100 has been reached. Optionally, other locations may be signified, such as bottom-most stroke location, or a mid- stroke location.

[ 0036 ] The actuator 228 may be mounted to a lower housing 236 of the pump body 220 by suitable fasteners 238 such as socket head cap screws or the like that may be received through flanges 236F (FIG. 2G) at a lower end of the lower housing 236. Other fastening means may be used. Lower housing 236 may include a recess 236R that receives the actuator shaft 228S, coupling 230, and a sensing portion of the sensor 234. The sensor 234 may be mounted to the lower housing 236 and access the flag 230F through a hole 236H (FIG. 2G) formed through a sidewall of the lower housing 236.

[ 0037 ] Coupled to the lower housing 236 at an upper end thereof may be a middle housing 240 (see also FIG. 2H) . The middle housing 240 may include the first chamber 222 and the shaft seals 227SL, 227SU at a lower and upper end thereof. The middle housing 240 may also include a first chamber inlet 2421, and a first chamber outlet 2420 to and from the first chamber 222, respectively. The first chamber inlet 2421 is adapted to fluidly couple to a liquid source such as by a conduit, and the first chamber outlet 2420 is adapted to fluidly couple to a dispensing and/or aspirating device such as a probe or liquid receptacle (See FIGs. 3A-3C) also by a conduit or a flow-controllable passage. The piston 226, in the depicted embodiment, extends through the middle housing 240 and the shaft seals 227SL, 227SU seal against the shaft sealing portions 227L, 227U. The shaft seals 227SL, 227SU may each be a spring energized U-Cup reciprocating type seals, for example. Other suitable dynamic seals may be used.

[0038] Coupled to the middle housing 240 may be an upper housing 244 (See also FIG. 21) . Upper housing 244 may include the second chamber 224 and the second piston portion 227U. The upper housing 244 may also include a second chamber inlet 2461, and a second chamber outlet 2460 to and from the second chamber 224, respectively. The second chamber inlet 2461 is adapted to fluidly couple to a liquid source such as by a conduit, and the second chamber outlet 2460 is adapted to fluidly couple to a dispensing and/or aspirating device such as a probe or liquid receptacle (See FIGs. 3A-3C) also by a conduit or a flow-controllable passage. The various inlets and outlets, 2421, 2420, 2461, 2460 may be angled to allow bubbles to easily be dislodged during a bleeding process thereof.

[0039] Each of the middle housing 240 and the upper housing 244 may be manufactured from a transparent material, such as an acrylic plastic such that any bubbles therein may be seen and removed. The shaft seals 227SL, 227SU may include a housing seal that functions to seal between the middle housing 240 and the upper housing 244, and the middle housing 240 and the lower housing 236 to seal gaps there between. The upper housing 244 and middle housing 240 may be coupled to the lower housing 236 with common fasteners 247 (e.g., bolts) passing through apertures 248 in the upper housing 244 and apertures 249 in the middle housing 240 and threading into threaded holes 250 in the lower housing 236 (FIG. 2G) . Other fastening means may be employed. [ 0040 ] Now referring to FIGs. 3A-3C, several embodiments of liquid delivery systems 300A-300C are shown. The liquid delivery systems 300A-300C may be included in an instrument, such as a clinical analyzer and are configured and adapted to deliver one or more liquids to one or more devices. Each of the liquid delivery systems 300A-300C includes at least one liquid source, such as first liquid source 318. Some embodiments may include more than one liquid source such as first liquid source 318 and second liquid source 319. The one or more liquid sources (e.g., 318 or 318 and 319) may be fluidly coupled to the multi-chamber pump apparatus 200. The multi-chamber pump apparatus 200 may be as described herein.

[ 0041 ] In particular, the one or more liquid sources (e.g., 318 or 318 and 319) may be fluidly coupled to the respective first chamber inlet 2421 and second chamber inlet 2461 of the multi-chamber pump apparatus 200. The fluid coupling may be provided by any suitable passage, such as one or more liquid- carrying conduits 321, for example. On an output side, the respective first chamber outlet 2420 and second chamber outlet 2460 of the multi-chamber pump apparatus 200 are fluidly coupled to a dispensing and/or aspirating device 325. The fluid coupling on the output side of the multi-chamber pump 200 may be provided by any suitable passage, such as a flow- controllable passage comprising one or more conduits 321 and one or more valves 323, for example. A suitable controller 327 may be provided to carry out the dispensing and/or aspirating by the multi-chamber pump 200.

[ 0042 ] The various liquid sources 318, 319 may need to be replenished from time to time. Such replenishment may be by manual refilling, or automatic refill as dictated by a level sensor (e.g., a float type sensor) situated at an appropriate level in a tank, the valve (not shown) may be opened and a fresh supply of liquid may be allowed to enter. For example, the liquid sources 318, 319 may be purified water, saline buffer solution, concentrated reagent, detergent, wash liquid, or the like. However, other liquids may also be dispensed.

[ 0043 ] The various liquids may be used, for example, in the liquid delivery systems 300A-300C. In some embodiments, such as shown in FIG. 3A, the multi-chamber pump 200 may dispense a first liquid (e.g., a reagent, a liquid detergent or wash liquid) from the first liquid source 318 in a first flow controllable passage 329 to a vessel comprising the dispensing and/or aspirating device 325, and a second liquid (e.g., water) from the second liquid source 319 in a second flow controllable passage 341 to the vessel. The vessel may be used to wash and/or clean one or more probes, for example. In particular, the liquids from the first liquid source 318 and the second liquid source are generally desired to be dispensed at different volume flow rates. In other embodiments, the first liquid from the first liquid source 318 in a first flow controllable passage 329 and a second liquid from the second liquid source 319 may be both provided to a vessel comprising the dispensing and/or aspirating device 325. Another pump (not shown) may then dispense the mixture of the first liquid and second liquid from the dispensing and/or aspirating device 325 to another location. For example, a volume output from the first chamber outlet 2420 may be VI, and a volume output from the second chamber outlet 2460 may be V2, and V2 > VI. In other embodiments, V2 > 3V1, V2 > 5V1, or even V2 > 8V1 in some embodiments.

[ 0044 ] In some embodiments, a liquid (e.g., purified water) may be used to dilute fluid samples, prepare reagents (e.g., where the purified water is added to a solid or powdered reagent material), used as a liquid backing to dispense and/or aspirate liquid reagents (e.g., concentrated reagents), used as a liquid backing to aspirate or dispense biological fluid specimens, and/or to wash sample containers. For example, the purified water may be purified to a level that is suitable to be used for aspiration and/or dispensing in the testing of analytes or other substances in a bio-fluid (blood, plasma and/or serum, urine, interstitial fluid, spinal fluid, cerebral fluid, etc.) . For example, a purity of the purified water may be sufficient to meet the standards for ASTM/NCCLS Type 1-IV and/or Type A-C, for example. Preferably, ASTM/NCCLS Type 1 and Type A purity standards may be provided.

[ 0045 ] In another depicted embodiment, the liquid delivery system 300B includes a probe fluidly coupled to the multi- chamber pump 200 that functions as the dispensing and/or aspirating device 325. In particular, the multi-chamber pump 200 may both aspirate and dispense a liquid (e.g., a biological fluid sample or liquid reagent) by using the first liquid source 318 as a backing liquid to accomplish low volume aspiration and dispensing, by using the first chamber 222 of the multi-chamber pump 200 to achieve precision at aspirating a relatively small volume of the liquid. Using the liquid as a backing liquid means that none or only a small amount of the backing liquid from the first liquid source 318 may be dispensed, but the backing liquid is present in the first flow controlled passage 329 to draw in the liquid thorough the probe when aspirating, and push out the liquid out of the probe 325 when dispensing.

[ 0046 ] The second liquid from the second liquid source 319 may be a wash liquid or purified water that is provided in a second flow controllable passage 341 to the probe 325 at a relatively higher volume V2 > VI, V2 > 3V1, V2 > 5V1, or even V2 > 8V1. In the depicted embodiment, the flow control of the liquid aspiration and/or dispensing from the flow controllable passages 329, 341 is accomplished by control of one or more valves 323 and operation of the multi-chamber pump apparatus 200 by suitable control signals from the controller 327.

[ 0047 ] In another depicted embodiment, the liquid delivery system 300C includes a probe fluidly coupled to the multi- chamber pump 200 that functions as the dispensing and/or aspirating device 325. In particular, the multi-chamber pump 200 may both aspirate and dispense a liquid (e.g., a biological fluid sample or liquid reagent) by using the first liquid from the first liquid source 318 as a backing liquid to accomplish precise aspiration and dispensing. This is done by using the first chamber 222 of the multi-chamber pump 200 to achieve precision at aspirating a relatively small volume of the liquid, such as less than about 100 pL . The system 300C may also dispense the first liquid (e.g., purified water) from the first liquid source 318 by using the second chamber 224 of the multi-chamber pump 200 to achieve precision at aspirating a relatively larger volume of the first liquid, such as a volume greater than about 200 pL, greater than about 500 pL, greater than about 1000 pL, greater than 5000 pL, or even 9000 pL or more in some embodiments. In the depicted embodiment, the flow control of the liquid aspiration and/or dispensing is accomplished by control of one or more control valves 323 and operation of the multi-chamber pump apparatus 200 by suitable control signals from the controller 327. For example, when dispensing the first liquid at the relatively lower volume, the flow controllable passage 339 is opened, while the flow controllable passage 341 is closed. Similarly, when dispensing at the relatively large volume, the flow controllable passage 341 is opened, while the flow controllable passage 329 is closed .

[ 0048 ] Accordingly, in each of the preceding embodiments, precise aspirating and/or dispensing may be achieved at both relatively high volume and relatively low volume, because the respective first and second chambers 222, 224 may be appropriately sized so that each operates at above approximately 25% of its volume dispensing capacity, at above approximately 50% of its volume dispensing capacity, or even above approximately 75% of its volume dispensing capacity in some embodiments. In operation, the multi-chamber pump apparatus 200, in some embodiments, should be able to meter to a volumetric accuracy of at least about +/- 5% or less at low volume dispense or aspiration of less than about 100 pL . Likewise, the multi-chamber pump apparatus 200, in some embodiments, should be able to meter to a volumetric accuracy of at least about +/- 1% or less at relatively high volume dispense or aspiration of greater than about 200 pL, greater than about 500 pL, or even greater than about 1000 pL in some embodiment. For example, an accuracy of +/- 10.0 pL or less at relatively high volume dispense and/or aspiration of greater than about 1000 pL may be provided.

[ 0049 ] In one operational method according to embodiments of the invention, the liquid delivery system 300B including the multi-chamber pump apparatus 200 is used to aspirate and then dispense a biological liquid. For example, in the above- mentioned "chase" or "neat" methods, a robot operable based upon control signals from a robot controller may position the probe 325 into a sample container containing a volume of biological liquid (e.g., blood or a blood plasma) . The multi- chamber pump 200 may then draw (aspirate) a small volume of the biological liquid (e.g., less than about 100 pL) into the interior channel of the probe 325 from the sample container via appropriate signals from the controller 327, move the probe 325 via operation of the robot, and transfer (dispense) the small amount of the biological liquid into a test vessel (e.g., a cuvette) . This operation is carried out using the first chamber 222, the first flow controllable passage 329, and the first liquid from the first liquid source 318 as the backing liquid. During the act of dispensing, the second flow controllable passage 341 is close, such that there is no flow therein. Once the relatively low volume dispensing of the biological liquid is completed, this dispensing may be chased by operating the multi-chamber pump 200 and dispensing a relatively larger volume of the second liquid 219 through second flow controllable passage 341 and out of the probe 325 into the test container. Thus, the relatively larger volume of liquid may be dispensed with excellent accuracy. The probe 325 and first chamber 222 may also be used to aspirate and dispense liquid reagent from a reagent container as needed for the testing operation. The system 300C may also be used for carrying out the "chase" and/or "neat" method.

[ 0050 ] According to another aspect, a liquid delivery method according to some embodiments will now be described with reference to FIG. 4. The liquid delivery method 400 includes, in 402, providing, in 404, at least one liquid source containing a liquid, providing a multi-chamber pump apparatus fluidly coupled to the at least one liquid source, the multi- chamber pump apparatus having a pump body with a first chamber and a second chamber, a piston having a first piston portion of a first pump area Al received in the first chamber, and a second piston portion of a second pumping area A2 received in the second chamber, providing, in 406, a dispensing and/or aspirating device fluidly coupled to a first chamber outlet of the first chamber, and a second chamber outlet of the second chamber, and translating the piston to pump liquid to the dispensing and/or aspirating device in 408.

[ 0051 ] While the invention is susceptible to various modifications and alternative forms, specific system and apparatus embodiments and methods thereof have been shown by way of example in the drawings and are described in detail herein. It should be understood, however, that it is not intended to limit the invention to the particular systems, apparatus, or methods disclosed, but, to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A multi-chamber pump apparatus, comprising:

a pump body containing a first chamber and a second chamber, each adapted to contain a liquid;

a piston having

a first piston portion of a first pump area Al received in the first chamber, and

a second piston portion of a second pumping area A2 received in the second chamber; and

an actuator coupled to the piston.

2. The multi-chamber pump apparatus of claim 1, comprising A2

> Al.

3. The multi-chamber pump apparatus of claim 1, comprising A2

> 3A1.

4. The multi-chamber pump apparatus of claim 1, comprising A2

> 5A1.

5. The multi-chamber pump apparatus of claim 1, comprising a coupling attaching the piston to a shaft of the actuator.

6. The multi-chamber pump apparatus of claim 5, comprising a sensor mounted to the pump body and a flag extending from the coupling wherein the flag is configured to interact with the sensor to provide information concerning a position of the piston .

7. The multi-chamber pump apparatus of claim 5, wherein the pump body comprises:

a lower housing coupled to the actuator, the lower housing receiving the coupling and a shaft of the actuator.

8. The multi-chamber pump apparatus of claim 1, wherein the pump body comprises :

a lower housing coupled to the actuator;

a middle housing coupled to the lower housing, the middle housing containing the first chamber and a first chamber inlet and a first chamber outlet; and

an upper housing coupled to the middle housing, the upper housing containing the second chamber and a second chamber inlet and a second chamber outlet.

9. The multi-chamber pump apparatus of claim 8, wherein the middle housing and the upper housing comprise a transparent material .

10. The multi-chamber pump apparatus of claim 1, wherein the piston comprises co-axial cylinders, and the first piston portion of has a diameter Dl, and the second piston portion has a diameter D2, and Dl > D2.

11. A liquid delivery system, comprising:

at least one liquid source;

a multi-chamber pump apparatus fluidly coupled to the at least one liquid source, the multi-chamber pump apparatus having a pump body with a first chamber and a second chamber, a piston having a first piston portion of a first pump area Al received in the first chamber, and a second piston portion of a second pumping area A2 received in the second chamber;

a dispensing and/or aspirating device fluidly coupled to a first chamber outlet of the first chamber, and a second chamber outlet of the second chamber;

a first flow-controllable passage fluidly coupled to the first chamber; and

a second flow-controllable passage fluidly coupled to the second chamber.

12. The liquid delivery system of claim 11, comprising:

the first flow-controllable passage fluidly coupled between the first chamber outlet and the dispensing and/or aspirating device; and

the second flow-controllable passage fluidly coupled between the second chamber outlet and the dispensing and/or aspirating device.

13. The liquid delivery system of claim 11, wherein the dispensing and/or aspirating device comprises a probe receptacle .

14. The liquid delivery system of claim 11, wherein the dispensing and/or aspirating device comprises a probe.

15. A liquid delivery method, comprising:

providing at least one liquid source containing a liquid; providing a multi-chamber pump apparatus fluidly coupled to the at least one liquid source, the multi-chamber pump apparatus having a pump body with a first chamber and a second chamber, a piston having a first piston portion of a first pump area Al received in the first chamber, and a second piston portion of a second pumping area A2 received in the second chamber;

providing a dispensing and/or aspirating device fluidly coupled to a first chamber outlet of the first chamber, and a second chamber outlet of the second chamber; and

translating the piston to pump liquid to the dispensing and/or aspirating device.

16. The method of claim 15, comprising:

controlling flow in both a first flow-controllable passage fluidly coupled between the first chamber outlet and the dispensing and/or aspirating device and a second flow- controllable passage fluidly coupled between the second chamber outlet and the dispensing and/or aspirating device.

17. The method of claim 16, comprising:

the first flow-controllable passage and the second flow controllable passage are simultaneously open.

18. The method of claim 16, comprising:

one or the first flow-controllable passage and the second flow controllable passage is open and one of the first flow- controllable passage and the second flow controllable passage is closed.

19. The method of claim 15, comprising:

providing a first liquid source coupled to a first chamber inlet of the first chamber, and

providing a second liquid source fluidly coupled to a second chamber inlet of the second chamber.

20. The method of claim 19, comprising:

dispensing a first liquid from the first liquid source from the first chamber outlet of the first chamber; and

dispensing a second liquid from the second liquid source from a second chamber outlet of the second chamber. The method of claim 20, comprising:

the dispensing of the first liquid and the dispensing of second liquid occur simultaneously.