WO2015009623A1

WO2015009623A1 - Multi-chamber cam-actuated piston pump

Info

Publication number: WO2015009623A1
Application number: PCT/US2014/046532
Authority: WO
Inventors: Kevin P. Cowan
Original assignee: Bayer Medical Care Inc.
Priority date: 2013-07-15
Filing date: 2014-07-14
Publication date: 2015-01-22

Abstract

A fluid pumping device includes a pump housing having a longitudinal axis and a driveshaft rotatable relative to the pump housing about the longitudinal axis. The driveshaft has a first cam surface at a terminal end of the driveshaft. The fluid pumping device further includes at least one piston disposed within the pump housing. The at least one piston has a second cam surface operatively engaged with the first cam surface of the driveshaft. The at least one piston is reciprocably movable along the longitudinal axis of the pump housing in response to an engagement of the first cam surface with the second cam surface.

Description

MULTI-CHAMBER CAM-ACTUATED PISTON PUMP

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Patent Application No. 61/846,387 entitled "Multi- Chamber Cam- Actuated Piston Pump", filed on July 15, 2013, the disclosure of which is incorporated herein in its entirety.

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

[0002] The present disclosure is directed generally to a fluid delivery system having a fluid pumping device and an associated drive system for fluid delivery applications. In specific embodiments, the fluid delivery system may have use in medical diagnostic and therapeutic procedures, and, in particular, to a multi-chamber cam-actuated piston pump and an associated drive system for fluid delivery applications in medical diagnostic and therapeutic procedures.

Description of the Related Art

[0003] A number of medical procedures require a delivery of one or more fluids to a patient in a precisely controlled manner. To facilitate this requirement, a variety of fluid delivery devices have been developed. Fluid delivery devices may also have use for fluid delivery in other non-medical applications, such as industrial applications or analytical applications. A system commonly used to deliver one or more fluids to a patient is a gravity- feed system where one or more fluid containers are supported above the level of the patient' s body and where the flow rate to the patient is controlled by the gross pressure of a clamp upon the flexible tube extending between the one or more containers and the patient. Various manually-operated devices are also known for delivery of one or more fluids under pressure. In addition, a plurality of powered syringe-based fluid injection systems and peristaltic pumps have been used for delivering pressurized fluids to patients while controlling flow rates and volumetric delivery of the fluids.

[0004] One limitation of syringe-based fluid delivery systems is the need to refill or replace each syringe after fluid has been expelled therefrom. To alleviate this problem and to provide more precise control of flow rates and volumetric delivery of fluids, positive displacement pump platforms have been developed. These devices eliminate the use of syringes and provide increased pressure ranges over peristaltic pumps. However, there are several disadvantages present in the foregoing positive displacement pump platforms known in the medical field and other fields. For example, conventional positive displacement pumps include many moving components that require precise manufacturing tolerances. Such construction increases the complexity and cost of the pump. Another disadvantage present in the foregoing positive displacement pump examples, particularly multi-piston positive displacement pumps, is that as the pistons in multi-piston positive displacement pumps sequentially deliver pressurized fluid to the pump outlet, there are fluctuations or "pulsatility" in the flow rate as the fluid source transitions from one piston to the next.

SUMMARY OF THE DISCLOSURE

[0005] In view of the foregoing, a need exists for an improved fluid delivery system having a fluid pumping device and an associated drive system for fluid delivery applications, for example, but not limited to medical diagnostic and therapeutic procedures. There is an additional need in the medical field and other fields for a fluid delivery system that provides a more precise control of flow rates and volumetric delivery of fluids compared to existing fluid delivery systems. Additionally, a need exists for a fluid delivery system with a reduced number of moving components that simplify the construction and reduce the cost of the fluid delivery system. There is a further need in the art for a fluid delivery system that reduces fluctuations or "pulsatility" in the flow rate.

[0006] In one embodiment, the improved fluid delivery system may be in the form of a fluid pumping device having a pump housing with a longitudinal axis and a driveshaft rotatable relative to the pump housing about the longitudinal axis. The driveshaft may have a first cam surface at a terminal end of the driveshaft. At least one piston may be disposed within the pump housing and may have a second cam surface operatively engaged with the first cam surface of the driveshaft. The at least one piston may be reciprocably movable along the longitudinal axis of the pump housing in response to an engagement of the first cam surface with the second cam surface as the driveshaft is rotated. The fluid pumping device may further include a drive system configured for rotating the driveshaft. A first pumping chamber may be provided between the driveshaft and a first end of the at least one piston and/or a second pumping chamber may be provided between a second end of the at least one piston and a distal end of the pump housing. A volume of the first pumping chamber may be equal to or different from a volume of the second pumping chamber.

[0007] In another embodiment, the fluid pumping device may include at least one inlet for delivering fluid into at least one of the first and second pumping chambers and at least one outlet for delivering fluid from at least one of the first and second pumping chambers. The first cam surface may be inclined at a first angle relative to the longitudinal axis and the second cam surface may be inclined at a second angle relative to the longitudinal axis. The first angle may be equal to or different from the second angle. A retaining member may be provided for preventing the at least one piston from rotating within the pump housing about the longitudinal axis. The retaining member may be a pin or tab that extends radially outward from the at least one piston such that the pin is retained within a slot extending along the longitudinal axis through at least a portion of the pump housing. At least one spring may be provided within the second pumping chamber. The at least one spring may be configured for providing a restoring force that acts on the second end of the at least one piston. The pump housing may have a substantially tubular structure extending between a proximal end in operative connection with the drive system and an opposing distal end. At least one inlet manifold may be configured for delivering first fluid to the first pumping chamber through a first inlet and/or to the second pumping chamber through a second inlet. At least one outlet manifold may be configured for delivering fluid from the first pumping chamber through a first outlet and/or from the second pumping chamber through a second outlet. In certain embodiments, a first fluid may be delivered to the first pumping chamber through a first inlet and a second fluid may be delivered to the second pumping chamber through a second inlet. The first and second fluids may be delivered from the first and second pumping chambers, respectively, through at least one outlet manifold. The first fluid and the second fluid may be selected from fluids for a variety of pumping processes. In specific embodiments, the first and second fluids may be selected from medical fluids, such as a contrast agent solution, a saline solution, or a solution of at least one medicament.

[0008] In another embodiment, the fluid pumping device may include a rotating valve member disposed within the pump housing and in selective fluid communication with at least one inlet configured for delivering fluid into at least one of the first and second pumping chambers and at least one outlet configured for delivering fluid from at least one of the first and second pumping chambers depending on a rotational orientation of the driveshaft relative to the longitudinal axis. The rotating valve member may have a first lobe that is substantially aligned with an inner sidewall of the pump housing and a second lobe that is offset from the inner sidewall of the pump housing to define a fluid chamber. A rotational position of the fluid chamber relative to the longitudinal axis may change with a rotation of the rotating valve member such that the fluid chamber may be selectively aligned with the at least one inlet and the at least one outlet during each revolution of the rotating valve member. The at least one inlet and the at least one outlet may be in fluid communication with at least one of the first pumping chamber and the second pumping chamber through respective inlet and outlet passageways extending through at least a portion of the driveshaft.

[0009] In another embodiment, an inlet collar may fluidly connect the at least one inlet to the inlet passageway and an outlet collar may fluidly connect the at least one outlet to the outlet passageway. The inlet collar and the outlet collar may have at least one channel that connects the at least one inlet and the at least one outlet to the respective inlet passageway and the outlet passageway.

[0010] In yet another embodiment, a sliding collar may be disposed between an outer surface of the driveshaft and at least a portion of an inner surface of the at least one piston. The sliding collar may be positioned within the housing such that it is reversibly slidable in a direction of the longitudinal axis to selectively open or close an inlet port and outlet port provided on the driveshaft. A movement of the sliding collar in a direction of the longitudinal axis may be constrained by a first stop and a second stop spaced apart from each other in the direction of the longitudinal axis. The first stop and the second stop may be provided on an outer surface of the driveshaft and are configured for limiting the movement of the sliding collar along the driveshaft in the direction of the longitudinal axis.

[0011] In another embodiment, a fluid pumping device may include a pump housing having a longitudinal axis and a driveshaft rotatable relative to the pump housing about the longitudinal axis. The driveshaft may have a driveshaft cam surface at a terminal end thereof. At least one first piston may be disposed within the pump housing along the longitudinal axis. The at least one first piston may have a first cam surface on a proximal end of the at least one first piston and in certain embodiments a second cam surface on a distal end of the at least one first piston. At least one second piston may be disposed within the pump housing along the longitudinal axis. The at least one second piston may have a third cam surface. The at least one first piston may be reciprocably movable along the longitudinal axis of the pump housing in response to an engagement of the first cam surface with the driveshaft cam surface and/or the second cam surface with the third cam surface. The at least one second piston may be rotatably movable about the longitudinal axis of the pump housing in response to the engagement of the third cam surface with the second cam surface. The at least one second piston may be coupled with the driveshaft such that rotation of the driveshaft causes the at least one second piston to rotate. A first pumping chamber may be provided between the driveshaft and the at least one first piston and a second pumping chamber may be provided between the at least one first piston and the at least one second piston. In certain embodiments, at least a third pumping chamber may be provided at the distal end of the second piston. At least one inlet may be provided for delivering fluid into at least one of the first, second, and third pumping chambers and at least one outlet may be provided for delivering fluid from at least one of the first, second, and third pumping chambers. The driveshaft cam surface may be inclined at a driveshaft angle relative to the longitudinal axis, the first cam surface may be inclined at a first angle relative to the longitudinal axis, the second cam surface may be inclined at a second angle relative to the longitudinal axis, and the third cam surface may be inclined at a third angle relative to the longitudinal axis. The driveshaft, first, second and/or third angles may be the same or different from each other.

[0012] These and other features and characteristics of the fluid pumping device, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only, and are not intended as a definition of the limits of the disclosure. As used in the specification and the claims, the singular form of "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a schematic view of a multi-chamber cam-actuated pump in accordance with an embodiment of the present disclosure.

[0014] FIG. 2 is a detailed view of one pumping chamber with a cam piston positioned in a first orientation.

[0015] FIG. 3 is a detailed view of the pumping chamber of FIG. 2 with the cam piston positioned in a second orientation.

[0016] FIG. 4 is a cross sectional view of a multi-chamber cam-actuated pump in accordance with another embodiment.

[0017] FIG. 5 is a schematic view of a multi-chamber cam-actuated pump in accordance with another embodiment.

[0018] FIG. 6A is a cross sectional view of a valve of the multi-chamber cam-actuated pump shown in FIG. 5 during an intake cycle.

[0019] FIG. 6B is a cross sectional view of the valve of the multi-chamber cam-actuated pump shown in FIG. 5 during an exhaust cycle. [0020] FIG. 7 is a schematic view of a multi-chamber cam-actuated pump in accordance with another embodiment.

[0021] FIG. 8 is a schematic view of a multi-chamber cam-actuated pump in accordance with another embodiment.

[0022] FIG. 9 is a schematic view of fluid intake and exhaust routing.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0023] The illustrations generally show preferred and non-limiting embodiments of the systems and methods of the present disclosure. While the description presents various embodiments of the devices, it should not be interpreted in any way as limiting the disclosure. Furthermore, modifications, concepts, and applications of the disclosure's embodiments are to be interpreted by those skilled in the art as being encompassed, but not limited to, the illustrations and description provided herein.

[0024] The following description is provided to enable those skilled in the art to make and use the described embodiments contemplated for carrying out the disclosure. Various modifications, equivalents, variations, and alternatives, however, will remain readily apparent to those skilled in the art. Any and all such modifications, variations, equivalents, and alternatives are intended to fall within the spirit and scope of the present disclosure. Further, for purposes of the description hereinafter, the terms "end", "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal", and derivatives thereof shall relate to the disclosure as it is oriented in the figures. The term "proximal" as used herein means closer to the drive system and the term "distal" as used herein means further from the drive system. However, it is to be understood that the disclosure may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the disclosure. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.

[0025] Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, a multi-chamber cam-actuated pump 10 (hereinafter "pump 10") and method for fluid delivery using the pump 10 will be described herein in detail. With initial reference to FIG. 1, the pump 10 may be used as part of a fluid delivery system. In various embodiments, the pump 10 may be used to deliver at least one fluid from a fluid source to a fluid destination. Fluids may include liquids and/or gases, such as, for example, industrial fluids, petroleum-based fluids, medical fluids, biological fluids, and the like. For example in certain embodiments, the pump 10 may be used to deliver at least one fluid from a fluid source to a patient in a medical diagnostic and/or therapeutic procedure. The pump 10 may be connected to a vial, a bag, a container, or other fluid source to deliver fluid to a fluid path set, such as a catheter, to the patient.

[0026] In one embodiment, the pump 10 generally includes a pump housing 12 and a drive system 13 that provides a motive force for operating the movable components of the pump 10. The following discussion initially sets forth the general structure and arrangement of the components of the pump 10, after which a discussion of the drive system 13 is provided along with a discussion of the interaction between the pump 10 and the drive system 13 to effect operation of the pump 10.

[0027] With continuing reference to FIG. 1, the pump 10 includes the housing 12 defining a first pumping chamber 14 and a second pumping chamber 16. The pump housing 12 may have a tubular structure, having a circular cross-section, extending between a proximal end in operative connection with the drive system 13 and an opposing distal end. The interior of the tubular structure of the pump housing 12 receives various components of the pump 10 configured for delivering fluid under pressure. The various components of pump 10 may be constructed from metal, plastic, glass, composite, and/or other materials. In one embodiment, the pump housing 12 is constructed from a medical grade plastic material. The pump housing 12 may be transparent or translucent to allow visual verification of the pump operation. In another embodiment, the pump housing 12 is opaque. The pump housing 12 defines a support for the pump components, as well as a connection point for connecting the fluid path set.

[0028] At least one piston 18 is reciprocably disposed within the housing 12 between the first pumping chamber 14 and the second pumping chamber 16 spaced apart distally along a longitudinal axis 15 of the pump housing 12. While FIG. 1 illustrates a single piston 18, other embodiments may include a plurality of pistons 18 arranged in series within the pump housing 12. The piston 18 is configured for reciprocal movement along the longitudinal axis 15 of the pump housing 12 in response to the rotational input from the drive system 13, as will be described herein. Reciprocal movement of the piston 18 within the pump housing 12 affects the delivery of fluid under pressure to a desired end point, such as a fluid path. In certain embodiments, the fluid path may be a patient fluid path set that delivers pressurized fluid to the patient. In one embodiment, the piston 18 is configured to fit within the interior of the pump housing 12 such that piston 18 can reciprocably slide within the interior of the pump housing 12.

[0029] The pump housing 12 includes a first inlet 20 and a first outlet 22 associated with the first pumping chamber 14. The first inlet 20 is adapted for delivering unpressurized fluid, or fluid pressurized at a first pressure, into the first pumping chamber 14, while the first outlet 22 is adapted for exhausting pressurized fluid, or fluid pressurized to a second pressure higher than the first pressure, from the first pumping chamber 14. Similarly, the second pumping chamber 16 includes a second inlet 24 and a second outlet 26. Similar to the first inlet 20 and the first outlet 22, the second inlet 24 is adapted for delivering unpressurized fluid, or fluid pressurized at a first pressure, into the second pumping chamber 16, while the second outlet 26 is adapted for exhausting pressurized fluid, or fluid pressurized to a second pressure higher than the first pressure, from the second pumping chamber 16. The volume of the first pumping chamber 14 may be smaller, larger, or equal to the volume of the second pumping chamber 16.

[0030] One-way inlet check valves 28 may be provided at the first and second inlets 20, 24 to effect a one-way fluid flow into the first and second pumping chambers 14, 16. Similarly, one-way outlet check valves 30 may be provided at the first and second outlets 22, 26 to effect a one-way fluid flow out of the first and second pumping chambers 14, 16. First and second inlets 20, 24 may be connected by way of an inlet fluid line 32 that delivers fluid from the fluid source. In one embodiment, the inlet fluid line 32 is connected at a distal end 33 to a bulk fluid source (not shown), such as at least one fluid container having a quantity of a medical fluid stored therein. A proximal end 35 of the inlet fluid line 32 delivers the fluid from the fluid source to an inlet manifold 34. In one embodiment, the inlet manifold 34 is configured to deliver the fluid from the proximal end 35 of the inlet fluid line 32 to the first inlet 20 through the inlet check valve 28 and to the second inlet 24 via inlet line 36. In other embodiments, first and second inlets, 20, 24 may be connected to two fluid lines (not shown) that deliver a first fluid and a second fluid to the first pumping chamber 14 and the second pumping chamber 16, respectively.

[0031] With continuing reference to FIG. 1, pressurized fluid from the first pumping chamber 14 is delivered from the first outlet 22 to an outlet manifold 38 via an outlet line 40. The outlet manifold 38 may also receive pressurized fluid from the second outlet 26 of the second pumping chamber 16. The terminal end of the outlet manifold 38 is connected to a fluid path 42. In one embodiment, the fluid path 42 may include a connector 43 and/or like patient interface apparatus to facilitate a connection between the pump 10 and a patient fluid path set (not shown). For example, the connector 43 may be a threaded, luer-type connector, a clip connector, a bayonet-style connector, or any other connector configured to provide a fluid-tight connection between the fluid path 42 and the patient fluid path set. In other embodiments, the first outlet 22 may be connected to a first outlet fluid path (not shown) and the second outlet 26 may be connected to a second outlet fluid path (not shown) for delivery of at least a first fluid and optionally a second fluid, to separate destinations.

[0032] The pump 10 further includes a driveshaft 44 that is rotatably supported within the housing 12. The driveshaft 44 is connected to the drive system 13, such as a motor, to rotatably drive the driveshaft 44. The terminal end of the driveshaft 44 is disposed inside the first pumping chamber 14 and has a first cam surface 46 that is inclined at an angle a (shown in FIG. 2) relative to the longitudinal axis 15 of the housing 12. The first cam surface 46 may be planar or curved. As shown in FIG. 1, the longitudinal position of the driveshaft 44 relative to the housing 12 is maintained by a retaining element 68, such as a screw, that permits rotational movement of the driveshaft 44 about the longitudinal axis 15, but prevents longitudinal movement of the driveshaft 44 relative to the same. The driveshaft 44 may be solid or hollow. In an embodiment where the driveshaft 44 is hollow, the driveshaft 44 may have one or more fluid conduits for delivering fluid to or from the pump 10. In some embodiments, the first and second inlets 20, 24 and the first and second outlets 22, 26 may extend through at least a portion of the hollow driveshaft 44 and be in fluid communication with the first and second pumping chambers 14, 16. The first pumping chamber 14 is provided between the driveshaft 44 and a first end of the piston 18, while the second pumping chamber 16 is provided between the second end of the piston 18 and a distal end of the housing 12.

[0033] The piston 18 includes a second cam surface 50 operatively engaged with the first cam surface 46 during operation of the pump 10. Outer edges of the first and second cam surfaces 46, 50 are in sliding contact during operation of the pump 10, such that the piston 18 is movable longitudinally and reciprocably within the housing 12 with the movement of the first and second cam surfaces 46, 50. The second cam surface 50 is inclined at an angle β (shown in FIG. 2) relative to the longitudinal axis 15 of the housing 12. In one embodiment, the second cam surface 50 is complementary to the first cam surface 46 such that angle a is equal to angle β. With such a configuration, the first cam surface 46 may be aligned with the second cam surface 50 during an exhaust stroke of the pump 10 such that all fluid is expelled from the first pumping chamber 14. In another embodiment, angle a may be larger or smaller than angle β. In this embodiment, the first pumping chamber 14 may have a minimum volume of fluid remaining therein during the exhaust stroke of the pump 10.

[0034] In one embodiment, the angle of inclination of the first cam surface 46 and the second cam surface 50 relative to the longitudinal axis 15 is uniform such that the first cam surface 46 and the second cam surface 50 define a planar interface therebetween. In another embodiment, the first cam surface 46 and the second cam surface 50 may have a curved profile that defines a non-planar surface therebetween. As shown in FIGS. 1-3, the diameter of the first cam surface and the second cam surface is equal to the inner diameter of pump housing 12. However, in certain embodiments, the diameter of one or both of the first cam surface and the second cam surface may be less than the inner diameter of pump housing 12, wherein the driveshaft 44 and/or the first piston 18 may further include at least one flange, such as the flange 106 in FIG. 8, adjacent to the first cam surface 46 and/or second cam surface 50, wherein the diameter of the at least one flange 106 is equal to the inner diameter of pump housing 12. According to these embodiments, the volume of the first chamber may be increased dependent on the diameter of the at least one flange. The portion of the piston 18 and/or the driveshaft 44 that is recessed relative to the flange 106 defines an annular space that is filled with fluid but does not contribute to the overall volume output of the pump 10. In some embodiments, the at least one piston 18, the surface of the various cams, the driveshaft 44, and/or the flange 106 may have a coating or be made from a material having a low coefficient of friction, for example, polytetrafluoroethylene, to reduce the frictional losses as the driveshaft 44 rotates relative to the pump housing 12, as one cam rotates relative to an adjacent reciprocating cam, and/or as the piston 18 slides longitudinally relative to the pump housing 12. According to other embodiments, the surface of the various cams may comprise one or more bearing or bearing ring along the outer circumference of the cam, such as a rotating cam, to facilitate movement of the various cam surfaces relative to the adjacent reciprocating cam surface, or vice versa, with a low coefficient of friction,

[0035] The piston 18 further includes a retaining member, such as a pin or tab 52, that prevents the piston 18 from rotating about the longitudinal axis 15 during operation of the pump 10. In one embodiment, the pin or tab 52 extends radially outward from the piston 18 and is retained within a slot 54 extending along the longitudinal axis through at least a portion of the sidewall of the housing 12 to prevent rotation of the piston 18 while permitting longitudinal and reciprocal movement thereof within housing 12. In another embodiment, the retaining member may be in the form of one or more longitudinal projections extending radially outward from an outer surface of the piston 18 that are slidably retained within corresponding one or more longitudinal grooves on an inner surface of the sidewall of the housing 12. The projections and the grooves may be reversed such that the one or more longitudinal grooves may be provided on an outer surface of the piston 18 while the corresponding one or more longitudinal projections may be provided on an inner surface of the sidewall of the housing 12. The pump 10 further includes a spring 56 or other reversibly compressible member provided within the second pumping chamber 16 for providing a restoring force that acts on the piston 18, as will be described in greater detail herein. In certain embodiments, the second chamber 16 may be sealed and may contain a compressible gas that provides a restoring force that acts on piston 18.

[0036] One or more seal elements 58 may be provided around a circumference of the terminal end of the driveshaft 44 and at the opposing ends of the piston 18. The seal elements 58 provide a seal between an outer surface of the driveshaft 44 and the piston 18 and an inner surface of the housing 12. In one embodiment, at least one of the seal elements 58 is formed as an O-ring made from an elastomeric material. In other embodiments, the one or more sealing element 58 may be provided around a circumference of the at least one flange adjacent to the first cam surface and/or second cam surface.

[0037] With reference to FIGS. 2-3, operation of the pump 10 as shown in first pumping chamber 14 will now be described. As the drive system 13 (shown in FIG. 1) rotates the driveshaft 44, the first cam surface 46 rotates within the first pumping chamber 14. The first cam surface 46 is in continuous contact with the second cam surface 50 throughout the rotation of the driveshaft 44 such that at least an edge of the first cam surface 46 of the driveshaft 44 contacts the second cam surface 50 of piston 18. Due to the inclined arrangement of the first cam surface 46 and the second cam surface 50, the piston 18 is urged toward and away from the driveshaft 44 in a cyclical manner with the cyclical rotation of the driveshaft 44. The spring 56 (shown in FIG. 1) provides a restoring force that urges the piston 18 against the driveshaft 44 such that the first cam surface 46 and the second cam surface 50 contact each other continuously throughout the rotation of the driveshaft 44.

[0038] With specific reference to FIG. 2, the pump 10 is illustrated in a configuration where the first pumping chamber 14 is at its maximum intake volume. In certain embodiments, the maximum volume of the first pumping chamber 14, and therefore, the maximum volume of fluid delivered from the first pumping chamber 14 during a single revolution of driveshaft 44 may be calculated from the diameter of housing 12 and the values of angles a and β. The first cam surface 46 and the second cam surface 50 are arranged such that first ends 60, 62 of the first cam surface 46 and the second cam surface 50, respectively, are in physical contact, while second ends 64, 66 of the first cam surface 46 and the second cam surface 50, located diametrically opposite to the first ends 60, 62, are separated from each other. As the driveshaft 44 rotates, the pump 10 undergoes an exhaust cycle in the first pumping chamber 14. The piston 18 moves such that the first end 60 of the first cam surface 46 rotates out of alignment with the first end 62 of the second cam surface 50. This causes the volume of the first pumping chamber 14 to be reduced, thereby delivering the fluid from the first pumping chamber 14 through the first outlet 22. During this operation, the first inlet 20 is closed, for example by one-way check valve 28 or a sliding collar (described herein), to prevent entry of fluid from pumping chamber 14 into the first inlet 20 during the exhaust cycle of the pump 10.

[0039] With reference to FIG. 3, continued rotation of the driveshaft 44 causes the piston 18 to move such that first end 60 of the first cam surface 46 aligns with the second end 66 of the second cam surface 50 and the second end 64 of the first cam surface 46 makes contact with the first end 62 of the second cam surface 50. In this position, which is 180 degrees of driveshaft 44 rotation apart from the position shown in FIG. 2, the pump 10 is at the end of its exhaust cycle such that the volume of the first pumping chamber 14 is reduced to a minimum and all of the fluid is delivered therefrom. As the driveshaft 44 rotates further, the pump 10 undergoes an intake cycle such that the first end 60 of the first cam surface 46 rotates toward alignment with the first end 62 of the second cam surface 50. This causes the volume of the first pumping chamber 14 to be increased, thereby taking in the fluid through the first inlet 20. During this operation, the first outlet 22 is closed, for example by one-way check valve 30 or a sliding collar (as described herein), to prevent fluid from entering the first pumping chamber 14 from first outlet 22 during the intake cycle of the pump 10. The intake cycle in the first pumping chamber 14 thus occurs during the first 180° of rotation of the driveshaft 44 while the exhaust cycle occurs during the second 180° of rotation of the driveshaft 44. As driveshaft 44 continues rotating, the intake and exhaust cycles repeat once per every rotation. In an alternative embodiment, the driveshaft 44 and the drive system 13 may be configured for repeated reciprocal clockwise and counterclockwise rotations of 180°, thereby allowing an intake cycle during, for example, a 180° clockwise rotation and an exhaust cycle during the subsequent 180° counterclockwise rotation. The rate of fluid delivery and the total volume of fluid delivered may be determined by multiplying the total delivery volume of the one or more pumping chambers per revolution or cycle and the revolutions or cycles per minute of the driveshaft or the total revolutions or cycles of the driveshaft, respectively. [0040] As the piston 18 reciprocates in the above-described manner, a similar intake and exhaust cycle occurs in the second pumping chamber 16. However, the intake and exhaust cycles are offset by 180° of rotation of the driveshaft 44 relative to the intake and exhaust cycles of the first pumping chamber 14. Thus, as the first pumping chamber 14 undergoes an intake cycle, the second pumping chamber 16 undergoes an exhaust cycle, and vice versa. This offset intake/exhaust cycling between the first pumping chamber 14 and the second pumping chamber 16 may reduce fluctuations or pulsatility in the flow rate during fluid delivery.

[0041] With reference to FIG. 4, an alternate embodiment of the pump 100 is shown. The pump 100 includes a pump housing 102 with a plurality of pistons 104a-104d disposed within the housing 102. Each of the plurality of pistons 104a-104d includes a first cam surface 106a-106d opposite a second cam surface 108a-108d. The plurality of pistons 104a- 104d is arranged in series along a longitudinal length of the housing 102.

[0042] The pump 100 further includes a driveshaft 110 that is rotatably supported within the housing 102. The driveshaft 110 is connected to a drive system (not shown), such as a motor, to rotatably drive the driveshaft 110. The terminal end of the driveshaft 110 is disposed inside a first pumping chamber 112a and has a driveshaft cam surface 114 that is angled relative to a longitudinal axis 15 of the housing 102. The driveshaft cam surface 114 is in contact with the first cam surface 106a of the first piston 104a. The first piston 104a is fixed such that it cannot rotate within the housing 102, as described herein, while being able to slide longitudinally. For example, the first piston 104a may be constrained by a pin or tab that is retained within a slot or groove in the housing 102 to prevent rotation of the first piston 104a while permitting longitudinal movement thereof. In another embodiment, the first piston 104a may be formed from two or more portions coupled together to prevent relative rotation thereof. The portions of the first piston 104a may have a spring or other adjustment mechanism to allow the first cam surface 106a to move relative to the second cam surface 108a. In this way, the first piston 104a may be adjusted to control the pumping characteristics within the first and second pumping chambers 112a, 112b. Similar to the pump embodiment described above with reference to FIGS. 1-3, as the driveshaft 110 rotates, the first piston 104a slides such that the first cam surface 106a moves in and out of alignment with the driveshaft cam surface 114. This causes the first piston 104a to reciprocate longitudinally within the pump housing 102, thereby effecting the pressurization of fluid within the first pumping chamber 112a. [0043] As the first piston 104a slidably reciprocates within the housing 102, the second cam surface 108a of the first piston 104a interfaces with the first cam surface 106b of the second piston 104b. The second piston 104b is coupled directly to the driveshaft 110 and is substantially fixed from longitudinal movement within the housing 102 but is free to rotate about the longitudinal axis 15, for example at driveshaft 110 rotates. The longitudinal position of the second piston 104b may be adjustable along the length of the driveshaft 110. A second pumping chamber 112b is defined between the second cam surface 108a of the first piston 104a and the first cam surface 106b of the second piston 104b. As the first piston 104a slides within the housing 102, the first cam surface 106b of the second piston 104b simultaneously rotates with the rotation of the driveshaft 110 in and out of alignment with the second cam surface 108a of the first piston 104a. This causes the first piston 104a to slide back within the housing 102, thereby pressurizing the fluid in the first pumping chamber 112a depending on the rotational orientation of the second piston 104b. As shown in FIG. 4 the angle of the second cam surface 108a of the first piston 104a may be rotated 180° relative to the first cam surface 106a of the first piston 104a. Therefore, the intake and exhaust cycles of first pumping chamber 112a and second pumping chamber 112b may be offset by 180° or may be offset at another angle dependent on the relative angular position of the first cam surface 106a relative to the second cam surface 108a of first piston 104a. Alternatively, the second cam surface 108a of the first piston 104a may be rotated by any angle relative to the first cam surface 106a of the first piston 104a thereby changing the timing of the intake and exhaust cycles of the first pumping chamber 112a and the second pumping chamber 112b. By suitably selecting the rotation of the adjacent first cam surfaces 106a-x and second cam surfaces 108a-x and the offsets of the plurality of pumping chambers 112a-x, where x is equal to the number of pistons or pumping chambers, the fluctuations or pulsatility of the pump cycles may be reduced and substantially eliminated.

[0044] As the second piston 104b rotates within the housing 102, the second cam surface 108b of the second piston 104b interfaces with the first cam surface 106c of the third piston 104c. Similar to the first piston 104a, the third piston 104c may be constrained by a pin that is retained within a slot in the housing 102 to prevent rotation of the third piston 104c while permitting reciprocal longitudinal movement thereof. As shown in FIG. 4 the angle of the second cam surface 108b of the second piston 104b may be rotated 90° relative to the first cam surface 106b of the second piston 104b. As shown in FIG. 4, the third pumping chamber 112c is midway between a completed intake or exhaust cycle (depending on direction of rotation of driveshaft 110). Therefore, the intake and exhaust cycles of second pumping chamber 112b and third pumping chamber 112c may be offset by 90° or may be offset at another angle dependent on the relative angular position of the first cam 106b of the second piston 104b relative to the second cam surface 108b of second piston 104b. Alternatively, the second cam surface 108b of second piston 104b may be rotated by any angle relative to the first cam surface 106b of second piston 104b thereby changing the time of the intake and exhaust cycles of the second pumping chamber 112b and the third pumping chamber 112c. In another embodiment, the third piston 104c may be formed from two or more portions coupled together to prevent relative rotation thereof. The portions of the third piston 104c may have a spring or other adjustment mechanism to allow the first cam surface 106c to move relative to the second cam surface 108c. In this way, the third piston 104c may be adjusted to control the pumping characteristics within the third and fourth pumping chambers 112c, 112d. The third pumping chamber 112c is defined between the second cam surface 108b of the second piston 104b and the first cam surface 106c of the third piston 104c. As the second piston 104b rotates within the housing 102, the second cam surface 108b of the second piston 104b rotates in and out of alignment with the first cam surface 106c of the third piston 104c. This causes the third piston 104c to slidably reciprocate within the pump housing 102, thereby affecting the intake or pressurization/exhaust of fluid within the third pumping chamber 112c and a fourth pumping chamber 112d.

[0045] As the third piston 104c slidably reciprocates within the housing 102, the second cam surface 108c of the third piston 104c interfaces with the first cam surface 106d of the fourth piston 104d. Similar to second piston 104b, the fourth piston 104d is coupled directly to the driveshaft 110 and is substantially fixed from longitudinal movement within the housing 102 but is free to rotate about the longitudinal axis 15. The longitudinal position of the fourth piston 104d may be adjustable along the length of the driveshaft 110. A fourth pumping chamber 112d is defined between the second cam surface 108c of the third piston 104c and the first cam surface 106d of the fourth piston 104d. As the third piston 104c slides within the housing 102, the first cam surface 106d of the fourth piston 104d simultaneously rotates with rotation of the driveshaft 110 in and out of alignment with the second cam surface 108c of the third piston 104c. This causes the third piston 104c to slide back within the housing 102, thereby pressurizing the fluid in the third pumping chamber 112c depending on the rotational orientation of the second piston 104b. As shown in FIG. 4 the angle of the second cam surface 108d of the fourth piston 104d may be rotated 180° relative to the second cam surface 108b of the second piston 104b. As shown in FIG. 4, the fourth pumping chamber 112d is midway between a completed intake or exhaust cycle (depending on direction of rotation of driveshaft 110, and opposite that of the third pumping chamber 112c). Therefore, the intake and exhaust cycles of third pumping chamber 112c and fourth pumping chamber 112d may be offset by 180° or may be offset at another angle dependent on the relative angles. FIG. 4 illustrates a pump according to one embodiment having four pumping chambers 112a-d, however, it is understood that the number of pumping chambers may vary and may include any number of pumping chambers according to the fluid delivery application and the volume, rate, and/or pressure of the fluid to be delivered.

[0046] Each of the pumping chambers 112a-112d desirably includes an inlet 118 and an outlet 120. The inlet 118 is adapted for delivering unpressurized fluid into the pumping chambers 112a-112d, while the outlet 120 is adapted for delivering pressurized fluid from the pumping chambers 112a-112d. The volume of one pumping chamber 112a-112d may be the same, smaller, or larger than the volume of any of the remaining pumping chambers 112a- 112d. The volume of each pumping chamber may be determined by the relative angle of the cam surface and the inner diameter of the pumping chamber. In other embodiments, the inlet 118 and the outlet 120 may be provided within a multi-lumen driveshaft 110.

[0047] In one embodiment, the incline angle of the first cam surface 106a- 106d and the second cam surface 108a- 108d is uniform and defines a planar surface. In another embodiment, the first cam surface 106a-106d and the second cam surface 108a-108d may have a non-uniform incline angle that defines a non-planar surface. The angles may be offset such that the intake cycle of one pumping chamber 112a-112d coincides with the exhaust cycle of another pumping chamber 112a-112d. In the embodiment shown in FIG. 4, the pumping chambers 112a-112d are arranged such that one pumping chamber delivers pressurized fluid every 90° of driveshaft 110 rotation. In this way, four pumping cycles are delivered in an offset manner during each revolution of the driveshaft 110.

[0048] With reference to FIG. 5, the pump 10 is illustrated in accordance with another embodiment. The pump 10 generally includes a pump housing 12 and a drive system, such as the drive system 13 shown in FIG. 1, that provides a motive force for operating the movable components of the pump 10. The pump housing 12 may have a tubular structure and defines at least one pumping chamber, such as the first pumping chamber 14, inside the tubular structure. At least one piston 18 is reciprocably disposed within the housing 12 and movable in a reciprocating manner along the longitudinal axis 15 of the pump housing 12. While FIG. 5 illustrates a single piston 18, other embodiments may include a plurality of pistons 18 arranged in series within the pump housing 12 as described herein. The piston 18 is configured for reciprocal movement along the longitudinal axis 15 of the pump housing 12 in response to the rotational input from the drive system 13 (shown in FIG. 1), as described herein. The pump 10 further includes a driveshaft 44 that is rotatably supported within the housing 12. The terminal end of the driveshaft 44 is disposed inside the first pumping chamber 14 and has a first cam surface 46 that operatively engages the piston 18 which has a corresponding second cam surface 50. One or more additional pumping chambers may also be provided.

[0049] The pump housing 12 includes a first inlet 20 and a first outlet 22 in fluid communication with the first pumping chamber 14. The first inlet 20 is adapted for delivering unpressurized fluid, or fluid pressurized at a first pressure, into the first pumping chamber 14, while the first outlet 22 is adapted for exhausting pressurized fluid, or fluid pressurized to a second pressure higher than the first pressure, from the first pumping chamber 14.

[0050] A rotating valve member 70 is disposed within the pump housing 12 proximally from the terminal end of the driveshaft 44 and in selective fluid communication with the first inlet 20 and the first outlet 22 depending on the rotational orientation of the driveshaft 44 relative to the longitudinal axis 15. The rotating valve member 70 is synchronously driven by the driveshaft 44 such that it rotates with the rotation of the driveshaft 44 about the longitudinal axis 15. In some embodiments, the rotating valve member 70 is integrally formed with the driveshaft 44. In other embodiments, the rotating valve member 70 is secured to the driveshaft 44, for example by a retaining member, such as a pin or a tab (not shown). A central axis of the rotating valve member 70 is coaxially aligned with the longitudinal axis 15 of the pump housing 12. With reference to FIGS. 6A-6B, the rotating valve member has a first lobe 74 that is substantially aligned with the inner sidewall of the pump housing 12 and a second lobe 76 that is offset from the inner sidewall of the pump housing 12 to define a fluid chamber 78.

[0051] The rotational position of the fluid chamber 78 relative to the longitudinal axis 15 changes with the rotation of the rotating valve member 70 such that the fluid chamber 78 is selectively aligned with the first inlet 20 and the first outlet 22 during each revolution of the rotating valve member 70. When the rotating valve member 70 is arranged such that the second lobe 76 is aligned with the first inlet 20 (FIG. 6A), the fluid chamber 78 can receive fluid from a fluid source through the first inlet 20 during the intake cycle. During such fluid intake, the first lobe 74 blocks the first outlet 22 such that fluid is not exhausted from the pump 10. The fluid from the fluid chamber 78 is received in the first pumping chamber 14 such that it can be pressurized, as described herein. As the rotating valve member 70 rotates, the second lobe 76 transitions from being aligned with the first inlet 20 to come into alignment with the first outlet 22 (FIG. 6B). Pressurized fluid from the first pumping chamber 14 is received in the fluid chamber 78 and exhausted through the first outlet 22 during the exhaust cycle. During such fluid exhaust, the first lobe 74 blocks the first inlet 20 such that fluid cannot enter the pump housing 12. Intake and exhaust cycles are repeated with each rotation of the rotating valve member 70. According to certain embodiments the first inlet 20 and/or the first outlet 22 may comprise a one-way check valve. In other embodiments, the first inlet 20 and/or the first outlet 22 may not comprise a one-way check valve.

[0052] With reference to FIG. 7, the pump 10 is illustrated in accordance with another embodiment. The pump 10 shown in FIG. 7 is substantially similar to the pump 10 described herein with reference to FIGS. 2-3. Only the relative differences between the pump 10 in FIG. 7 and the pump 10 in FIGS. 2-3 will now be described. Whereas the pump 10 in FIGS. 2-3 has the first inlet 20 and the first outlet 22 in fluid communication with the first pumping chamber 14 through the sidewall of the pump housing 12, the pump 10 in FIG. 7 has the first inlet 20 and the first outlet 22 in fluid communication with the first pumping chamber 14 through the inlet and outlet passageways 80, 82, respectively, extending through at least a portion of the driveshaft 44. In this manner, the driveshaft 44 has at least a pair of lumens through which the fluid moves between the first inlet 20 and the first outlet 22. In some embodiments, the inlet and outlet passageways 80, 82 may be substantially parallel to and extend along the direction of the longitudinal axis 15.

[0053] In some embodiments, the first inlet 20 and the second outlet 22 are in fluid communication with the inlet and outlet passageways 80, 82 in the driveshaft 44 by way of an inlet collar 84 and an outlet collar 86. The inlet and outlet collars 84, 86 may extend around at least a portion of the circumference of the pump housing 12 or be formed integrally with the pump housing 12. While FIG. 7 shows the inlet and outlet collars 84, 86 being provided on opposite sides of the housing 12, in some embodiments, the inlet and outlet collars 84, 86 may be combined. In the embodiment shown in FIG. 9, the inlet and outlet collars 84, 86 are combined into a single, unitary structure configured for fluid intake and exhaust, for example at a proximal end of pump 10. As before, inlet and outlet collars 84, 86 allow fluid communication with inlet and outlet lumens 80 and 82, respectively, during rotation of driveshaft 44.

[0054] The inlet and outlet collars 84, 86 have at least one channel 88 that connects at least one of the first inlet 20 and the first outlet 22 to at least one of the inlet and outlet passageways 80, 82, respectively, in the driveshaft 44. The at least one inlet channel 88 may be configured as an annular cavity that surrounds the driveshaft 44. The inlet and outlet passageways 80, 82 have a collar port 90 in fluid communication with the at least one channel 88. As the driveshaft 44 rotates relative the inlet and outlet collars 84, 86, the collar ports 90 on the inlet and outlet passageways 80, 82 are in constant fluid communication with the at least one channel 88 allowing intake or exhaust of fluid depending on the cycle of the pumping chamber 14.

[0055] With continuing reference to FIG. 7, at least one piston 18 is reciprocably disposed within the housing 12 and movable in a reciprocating manner along the longitudinal axis 15 of the pump housing 12. While FIG. 7 illustrates a single piston 18, other embodiments may include a plurality of pistons 18 arranged in series within the pump housing 12 as described herein. The piston 18 is configured for reciprocal movement along the longitudinal axis 15 of the pump housing 12 in response to the rotational input from the drive system 13 (shown in FIG. 1), as described herein. The piston 18 is desirably at least partially hollow such that the driveshaft 44 extends through an annular opening in and lumen through the piston 18. The piston 18 may include a retaining member, such as a pin or tab 52 shown in FIG. 1, that prevents the piston 18 from rotating about the longitudinal axis 15 during operation of the pump 10.

[0056] The piston 18 further includes a sliding collar 96 that is disposed between an outer surface of the driveshaft 44 and at least a portion of the inner surface of the piston 18. The sliding collar 96 is positioned within the housing 12 such that it is slidable along the longitudinal axis 15 to selectively cover and uncover an inlet port 92 or an outlet port 94 that are in fluid communication with first inlet 20 or first outlet 22, respectively, and the first pumping chamber 14. In one embodiment, the inlet and outlet ports 92, 94 are in fluid communication with the first pumping chamber 14 by way of a key way on the driveshaft 44 and/or at least one the piston 18 and the sliding collar 96. Movement of the sliding collar 96 along the longitudinal axis 15 is constrained by a first stop 98 and a second stop 100 spaced apart from each other along the longitudinal axis 15. The first and second stops 98, 100 are provided on an outer surface of the driveshaft 44 and are configured for limiting the movement of the sliding sleeve 96 along the driveshaft 44 while allowing free rotation or sliding of the various other components of the fluid pump 10. In one embodiment, first and second stops 98, 100 may extend outward from the driveshaft 44 a distance less than our equal to the longitudinal thickness of sliding collar 96 to allow free rotation of the driveshaft and first and second stops 98, 100. According to another embodiment, first and second stops 98, 100 may be configured as a lateral groove in driveshaft 44, wherein the sliding collar 96 may have a pin or tab on an inner surface that fits into the groove to allow lateral sliding of the sliding collar 96. According to this embodiment, the proximal and distal ends of the groove may act as first and second stops 98, 100. When the sliding sleeve 96 is positioned against the first stop 98, the sliding collar 96 covers the outlet port 94 to prevent fluid from being exhausted from the first pumping chamber 14. In this position of the sliding collar 96, the inlet port 92 is open to allow the fluid to enter the first pumping chamber 14 through the inlet passageway 80. When the sliding sleeve 96 is positioned against the second stop 100, the sliding collar 96 covers the inlet port 92 to prevent fluid from being introduced into the first pumping chamber 14. In this position of the sliding collar 96, the outlet port 92 is open to allow the fluid to exit the first pumping chamber 14 through the outlet passageway 82. The sliding collar 96 thus moves in a reciprocal manner between the first and second stops 98, 100 during the rotation of the driveshaft 44.

[0057] Reciprocal movement of the sliding collar 96 is affected by the movement of the piston 18. The frictional force between an inner surface of the sliding collar 96 and the driveshaft 44 is smaller than the frictional force between an outer surface of the sliding collar 96 and an inner surface of the piston 18. In this manner, as the piston 18 moves longitudinally relative to the driveshaft 44, the movement of the piston 18 also causes the sliding collar 96 to move in the same direction as the piston 18 until the sliding collar 96 engages the first stop 98 or the second stop 100. The frictional force between the outer surface of the sliding collar 96 and the piston 18 is overcome once the sliding collar 96 engages the first stop 98 or the second stop 100, which causes the piston 18 to slide relative to the sliding collar 96. While the sliding collar 96 remains stationary or rotates with the rotation of the driveshaft 44, the piston 18 continues to move to the top/bottom of its stroke until its movement is reversed due to the cam configuration. With the reversed movement of the piston 18, the piston 18 frictionally engages the sliding collar 96 and continues to move the sliding collar 96 in an opposite direction away from one of the first stop 98 and the second stop 100 toward the other of the first stop 98 and the second stop 100.

[0058] Having described the structure of the embodiment of pump 10 shown in FIG. 7, the pumping process will now be described. Initially, the fluid flows from the first inlet 20 through the at least one channel 88 on the inlet collar 84. The fluid then flows through the collar port 90 and into the inlet passageway 80 extending through the driveshaft 44. The fluid is channeled through the inlet port 92 when in an open configuration according to the position of sliding collar 96 such that inlet port 92 is in fluid communication with the first pumping chamber 14. During the compression cycle, sliding collar 96 moves to a position such that inlet port 92 is not in fluid communication with first pumping chamber 14 and outlet port 94 is in fluid communication with first pumping chamber 14. After being compressed within the first pumping chamber 14, the fluid enters the outlet passageway 82 through an outlet port 94 on the driveshaft 44. The pressurized fluid flows through the outlet passageway 82 and is exhausted to the first outlet 22 through the collar port 90 and the at least one channel 88. The sliding collar 96 moves in response to the movement of the piston 18 between the first stop 98 and the second stop 100 to selectively open or close the inlet and outlet ports 92, 94.

[0059] While the sliding collar 96 in FIG. 7 is illustrated as being provided substantially within an annular space between the piston 18 and the driveshaft 44 such that fluid flows between a fluid path within the annular space between the piston 18 and the driveshaft 44, in another embodiment the sliding collar 96 may also be provided within at least a portion of the first pumping chamber 14. With reference to FIG. 8, the inlet and outlet ports 90, 92 are provided within the first pumping chamber 14. The sliding collar 96, which also provided within at least a portion of the first pumping chamber 14, slides between the first stop 98 and the second stop 100, as described herein. The sliding collar 96 is urged into sliding movement by frictional connection with and movement of the piston 18 until the sliding collar 96 engages the first stop 98 or the second stop 100. In a first position, such as when the sliding collar 96 is engaged against the first stop 98, the sliding collar 96 covers the outlet port 94 to prevent fluid from being exhausted from the first pumping chamber 14 and prevents fluid in outlet from backflowing into first pumping chamber 14. In this position of the sliding collar 96, the inlet port 92 is open to allow the fluid to enter the first pumping chamber 14 through the inlet passageway 80. When the sliding sleeve 96 is positioned against the second stop 100, the sliding collar 96 covers the inlet port 92 to prevent fluid from being introduced into the first pumping chamber 14 and prevent fluid from being exhausted from the first pumping chamber 14 through inlet port 92. In this position of the sliding collar 96, the outlet port 94 is open to allow the fluid to exit the first pumping chamber 14 through the outlet passageway 82. The sliding collar 96 thus moves in a reciprocal manner between the first and second stops 98, 100 through frictional connection with piston 18 during the rotation of the driveshaft 44.

[0060] In various embodiments, the pump 10 may be configured to deliver fluid in a range of 5-400 psi at rates ranging from 0.1 ml/s to 20 ml/s, although higher fluid delivery pressures and rates are within the general scope of the present fluid delivery pump. For example, in larger industrial settings, fluid delivery rates may be as large as 1000 ml/s or more. Fluid delivery volumes and rates are determined by the total volume of the one or more pumping chambers and the revolutions and revolutions per minute of the driveshaft 44. In some embodiments, the pump 10 may include an encoder 102 associated with the driveshaft 44 (shown in FIGS. 7 and 9) or one or more of the rotating cam surfaces to sense the rotational position of the driveshaft 44 relative to the longitudinal axis 15. The encoder 102 may be operatively connected to a controller 104 (shown in FIGS. 7 and 9) that calculates the number of revolutions or revolutions per minute of the driveshaft 44 necessary to deliver the desired volume of fluid. The controller 104 may be configured to control or monitor other functions of the pump 10, including, but not limited to, the fluid pressure, fluid delivery rate, and the fluid volume. In some embodiments, the controller 104 may be configured to measure the torque input on the driveshaft 44 and correlate the measurement to a pressure output of the pump 10. Controller 104 may be configured so that an operator can input parameters for operation of the pump, such as, for example, revolutions per minute, total revolutions, total length of time for fluid delivery, pump torque, and other fluid input/output parameters. In certain embodiments, the fluid pump may be configured for fluid removal, for example, for removing a volume of fluid from one position to a second position.

[0061] While several embodiments of a multi-chamber cam-actuated pump are shown in the accompanying figures and described hereinabove in detail, other embodiments will be apparent to, and readily made by, those skilled in the art without departing from the scope and spirit of the disclosure. For example, it is to be understood that this disclosure contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment. Accordingly, the foregoing description is intended to be illustrative rather than restrictive.

Claims

THE INVENTION CLAIMED IS:

1. A fluid pumping device, comprising:

a pump housing having a longitudinal axis;

a driveshaft rotatable relative to the pump housing about the longitudinal axis, the driveshaft having a first cam surface at a terminal end of the driveshaft; and

at least one piston disposed within the pump housing and having a second cam surface operatively engaged with the first cam surface of the driveshaft,

wherein the at least one piston is reciprocably movable along the longitudinal axis of the pump housing in response to an engagement of the first cam surface with the second cam surface.

2. The fluid pumping device of claim 1, further comprising a drive system configured for rotating the driveshaft.

3. The fluid pumping device of claim 1, wherein a first pumping chamber is provided between the driveshaft and a first end of the at least one piston and a second pumping chamber is provided between a second end of the at least one piston and a distal end of the pump housing.

4. The fluid pumping device of claim 3, wherein a volume of the first pumping chamber is equal to a volume of the second pumping chamber.

5. The fluid pumping device of claim 3, wherein a volume of the first pumping chamber is different from a volume of the second pumping chamber.

6. The fluid pumping device of claim 3, further comprising at least one inlet for delivering fluid into at least one of the first and second pumping chambers and at least one outlet for delivering fluid from at least one of the first and second pumping chambers.

7. The fluid pumping device of claim 1, wherein the first cam surface is inclined at a first angle relative to the longitudinal axis and wherein the second cam surface is inclined at a second angle relative to the longitudinal axis.

8. The fluid pumping device of claim 7, wherein the first angle is equal to the second angle.

9. The fluid pumping device of claim 7, wherein the first angle is different from the second angle.

10. The fluid pumping device of claim 1, further comprising a retaining member for preventing the at least one piston from rotating within the pump housing about the longitudinal axis.

11. The fluid pumping device of claim 10, wherein the retaining member is a pin that extends radially outward from the at least one piston such that the pin is retained within a slot extending through at least a portion of the pump housing.

12. The fluid pumping device of claim 3, further comprising a spring within the second pumping chamber, wherein the spring is configured for providing a restoring force that acts on the second end of the at least one piston.

13. The fluid pumping device of claim 1, wherein the pump housing has a substantially tubular structure extending between a proximal end in operative connection with the drive system and an opposing distal end.

14. The fluid pumping device of claim 3, further comprising at least one inlet manifold configured for delivering fluid to the first pumping chamber through a first inlet and to the second pumping chamber through a second inlet.

15. The fluid pumping device of claim 1, further comprising at least one outlet manifold configured for delivering fluid from the first pumping chamber through a first outlet and from the second pumping chamber through a second outlet.

16. The fluid pumping device of claim 1 , further comprising a rotating valve member disposed within the pump housing and in selective fluid communication with at least one inlet configured for delivering fluid into at least one of the first and second pumping chambers and at least one outlet configured for delivering fluid from at least one of the first and second pumping chambers depending on a rotational orientation of the driveshaft relative to the longitudinal axis.

17. The fluid pumping device of claim 16, wherein the rotating valve member has a first lobe that is substantially aligned with an inner sidewall of the pump housing and a second lobe that is offset from the inner sidewall of the pump housing to define a fluid chamber.

18. The fluid pumping device of claim 17, wherein a rotational position of the fluid chamber relative to the longitudinal axis changes with a rotation of the rotating valve member such that the fluid chamber is selectively aligned with the at least one inlet and the at least one outlet during each revolution of the rotating valve member.

19. The fluid pumping device of claim 6, wherein the at least one inlet and the at least one outlet are in fluid communication with at least one of the first pumping chamber and the second pumping chamber through respective inlet and outlet passageways extending through at least a portion of the driveshaft.

20. The fluid pumping device of claim 19, wherein an inlet collar fluidly connects the at least one inlet to the inlet passageway and an outlet collar fluidly connects the at least one outlet to the outlet passageway.

21. The fluid pumping device of claim 20, wherein the inlet collar and the outlet collar have at least one channel that connects the at least one inlet and the at least one outlet to the respective inlet passageway and the outlet passageway.

22. The fluid pumping device of claim 1, further comprising a sliding collar disposed between an outer surface of the driveshaft and at least a portion of an inner surface of the at least one piston.

23. The fluid pumping device of claim 22, wherein the sliding collar is positioned within the housing such that it is reversibly slidable in a direction of the longitudinal axis to selectively open or close an inlet port and outlet port provided on the driveshaft.

24. The fluid pumping device of claim 22, wherein a movement of the sliding collar in a direction of the longitudinal axis is constrained by a first stop and a second stop spaced apart from each other in the direction of the longitudinal axis.

25. The fluid pumping device of claim 24, wherein the first stop and the second stop are provided on an outer surface of the driveshaft and are configured for limiting the movement of the sliding collar along the driveshaft in the direction of the longitudinal axis.

26. A fluid pumping device, comprising:

a pump housing having a longitudinal axis;

a driveshaft rotatable relative to the pump housing about the longitudinal axis, the driveshaft having a driveshaft cam surface at a terminal end thereof;

at least one first piston disposed within the pump housing along the longitudinal axis and having a first cam surface at a proximal end of the first piston and a second cam surface at a distal end of the first piston; and

at least one second piston disposed within the pump housing along the longitudinal axis and engaged with the driveshaft, the at least one second piston having a first cam surface at a proximal end of the second piston and a second cam surface at a distal end of the second piston,

wherein the at least one first piston is reciprocably movable along the longitudinal axis of the pump housing in response to an engagement of the first cam surface with the driveshaft cam surface or engagement of the second cam surface with the first cam surface of the at least one second piston, and

wherein the at least one second piston is rotatably movable about the longitudinal axis of the pump housing.

27. The fluid pumping device of claim 26, wherein the at least one second piston is coupled with the driveshaft such that rotation of the driveshaft causes the at least one second piston to rotate.

28. The fluid pumping device of claim 26, wherein a first pumping chamber is provided between the driveshaft cam surface and the first cam surface of the at least one first piston and a second pumping chamber is provided between second cam surface of the at least one first piston and the first cam surface of the at least one second piston.

29. The fluid pumping device of claim 28, further comprising at least one inlet for delivering fluid into at least one of the first and second pumping chambers and at least one outlet for delivering fluid from at least one of the first and second pumping chambers.

30. The fluid pumping device of claim 26, wherein the first cam surface of the at least one first piston is inclined at a first angle relative to the longitudinal axis and wherein the second cam surface of the at least one first piston is inclined at a second angle relative to the longitudinal axis.