US20100209263A1 - Modular fluid pump with cartridge - Google Patents

Abstract

A modular fluid pump including: a pump motor that provides a motor force, a sealed housing cartridge removably coupled to the pump motor, wherein the housing cartridge is interchangeable with a replacement housing cartridge, a frame enclosed in the housing cartridge and having a plurality of rollers arranged on the frame, a drive coupling means for transmitting the motor force from the pump motor to the frame thereby inducing rotation of the frame, and a fluid conduit, wrapped under tension around at least one of the plurality of rollers, that facilitates fluid flow from an inlet region of the fluid conduit to an outlet region of the fluid conduit. Rotation of the frame causes the plurality of rollers to compress the fluid conduit at subsequent intervals, thereby driving fluid to the outlet region with a peristaltic movement.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims the benefit of U.S. Provisional Application No. 61/152,182, filed 12 Feb. 2009, which is incorporated in its entirety by this reference.
TECHNICAL FIELD
• This invention relates generally to the fluid pump field, and more specifically to an improved modular fluid pump in the fluid pump field.
BACKGROUND
• In the medical field, blood pumps are commonly used to provide extracorporeal life support to patients lacking sufficient cardiac function. For example, patients with cardiac failure may require cardiac support long enough to sustain the patient until recovery, heart transplantation, or implantation of a permanent artificial cardiac device. As another example, a patient undergoing cardiac bypass surgery require external means of pumping blood throughout their circulatory system. One kind of pump often used in such extracorporeal life support systems is a roller pump. In a typical roller pump, rollers press against a piece of tubing that is wrapped around the rollers and backed by a rigid raceway to advance fluid through the tubing. Roller pumps typically draw blood from a patient or a venous reservoir of blood supplied by the patient. However, roller pumps typically provide no inherent means of preventing draining of the venous reservoir, and if left unattended, will drain the venous reservoir and continue to pump air to the patient, which may be dangerous for the patient. Furthermore, the tubing in a roller pump has a limited lifetime due to repeated stress during operation, and must periodically be replaced. However, optimal operation of a roller pump typically requires an experienced and skilled operator to carefully set settings on the pump, such as occlusion settings (effectively the maximum amount of compression exerted on the tubing) or tubing tension (wrapping the tubing around the rollers with the proper amount of tension) to optimize the performance of the pump and reduce harmful effects to the patient. Thus, there is a need in the fluid pump field to create an improved modular fluid pump. This invention provides such an improved modular fluid pump.
BRIEF DESCRIPTION OF THE FIGURES
• FIGS. 1A-1C are a perspective view, plan view, and cross sectional view, respectively, of the fluid pump of a preferred embodiment;
• FIG. 2 is a non-contact variation of the drive coupling means in the fluid pump of a preferred embodiment;
• FIG. 3 is a contact variation of the drive coupling means in the fluid pump of a preferred embodiment;
• FIGS. 4A and 4B are a side view and a cross-sectional view, respectively, of the fluid conduit operating in the filled mode, in the fluid pump of a preferred embodiment;
• FIGS. 5A and 5B are a side view and a cross-sectional view respectively, of the fluid conduit operating in the collapsed mode, in the fluid pump of a preferred embodiment; and
• FIG. 6 is a schematic of the method of supplying a plurality of housing cartridges of a preferred embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
• The following description of preferred embodiments of the invention is not intended to limit the invention to these preferred embodiments, but rather to enable any person skilled in the art to make and use this invention.
1. Modular Fluid Pump System
• As shown inFIG. 1, the modular fluid pump too of the preferred embodiment includes: apump motor110 that provides a motor force; ahousing cartridge120 removably coupled to thepump motor110, in which thehousing cartridge120 is interchangeable with a replacement housing cartridge; aframe130 enclosed in thehousing cartridge120 and having a plurality ofrollers140 arranged on theframe130; a drive coupling means150 between thepump motor110 and theframe130, wherein the drive coupling means150 transmits the motor force to theframe130 to induce rotation of theframe130; and afluid conduit160, wrapped under tension around at least one of the plurality ofrollers140, that facilitates fluid flow from aninlet region162 of thefluid conduit160 to anoutlet region166 of thefluid conduit160. The rotation of theframe130 preferably causes the plurality ofrollers140 to compress thefluid conduit160 at subsequent intervals, thereby driving fluid to theoutlet region166 of the fluid conduit with a peristaltic movement. Themodular fluid pump100 preferably is used to pump blood and is part of an extracorporeal life support system. The fluid pump100 preferably interfaces with the circulatory system of the patient, receiving blood of the patient and pumping the blood to return to the patient. Thefluid pump100 preferably provides an outlet fluid pump pressure no more than a predetermined safe level and maintains safe levels of inlet region pressure to avoid harmful effects to the patient such as cavitation (formation of vapor bubbles in the fluid) and hemolysis (the lysis, or breaking open, of red blood cells). Thefluid pump100 is preferably a Starling pump that provides a flow output dependent on the flow input, and is preferably responsive to variations in hemodynamic changes of the patient, acting as an automatically adaptive reservoir. Thehousing cartridge120 of the fluid pump is preferably interchangeable with a replacement housing cartridge to provide a simple, easy way to replace the pump head portion (e.g., the fluid conduit and rollers) of thefluid pump100 due to reasons such as maintenance or wear. This interchangeability of housing cartridges increases the reliability and consistency of the fluid pump between uses of the fluid pump, reduces risk of user error that could be harmful to the patient, and simplifies use and maintenance of the fluid pump. The fluid pump may be used in any suitable application of a cardiac life support system, such supporting a patient during a cardiac bypass procedure, or supporting a patient with cardiac failure long enough to sustain the patient until recovery, heart transplantation, or implantation of a permanent artificial cardiac device. Furthermore, the fluid pump may interface with an oxygenator or other gas exchange device to provide a patient with cardiorespiratory support. The fluid pump may, however, be used to pump any suitable fluid.
• Thepump motor110 of the preferred embodiment functions to provide a motor force actuation for the plurality ofrollers140 on theframe130. Thepump motor110 is preferably a direct drive, brushless DC motor with high torque at low RPM, which increases reliability and efficiency that may be lost in a speed reduction gearhead and reduces audible noise. A brushless DC motor also typically has a relatively low emission of electromagnetic radiation, which reduces the likelihood of the fluid pump interfering with other nearby medical and electronic devices. However, the pump motor may be a brushed DC motor, a stepper motor, a single or polyphase AC motor, or any suitable actuator, and may be coupled to a transmission such as a geartrain and/or pulley system to increase the torque output and/or direct the output in a particular orientation. The exact specifications of thepump motor110 is preferably selected based on the desired application of the fluid pump; for example, in a fluid pump intended for pediatric patients, thepump motor110 preferably has a smaller physical size and provides a lower torque output to satisfy a lower required torque. In some variations, the pump motor preferably is coupled to amotor housing112. As shown inFIG. 1B, themotor housing112 preferably couples to a face of thepump motor110 that receives thehousing cartridge120, but the motor housing may alternatively enclose the pump motor. Themotor housing112 preferably includes amating surface114 that mates with thehousing cartridge120. As best shown inFIG. 1A, themotor housing112 preferably includes a circular lip forming a recess that receives thehousing cartridge120 in a sliding manner, but may additionally and/or alternatively include any suitable shaped lip, recess, or other mating surface into which thehousing cartridge120 slides or otherwise engages with. Themotor housing112 is preferably biased, such as with a taper or a keyway, such that thehousing cartridge120 is constrained to couple to the motor housing or pump motor in a particular orientation, which helps ensure that the housing cartridge is placed appropriately for correct pump operation. Thehousing cartridge120 may additionally and/or alternatively include tabs, notches, latches, magnetic snaps, or other mechanisms that help lock thehousing cartridge120 into place on themating surface114 of themotor housing112, thereby securely coupling thehousing cartridge120 to thepump motor110. However, the fluid pump may alternatively lack amotor housing112, such that thehousing cartridge120 removably couples solely to thepump motor110.
• Thehousing cartridge120 of the preferred embodiment functions to enclose the pump head components and to removably couple with thepump motor110 such that thehousing cartridge120 is interchangeable with a replacement housing cartridge. Thehousing cartridge120 is preferably substantially airtight sealed and includes aport122 that facilitates adjustment of the pressure within the housing cartridge. The pressure within the housing may be a fixed or variable subatmospheric or superatmospheric pressure. In one variation, thepressure control port122 is a vacuum port that couples to avacuum pump180 and facilitates formation of a vacuum (i.e., negative pressure) within the housing cartridge. In another variation, thepressure control port122 couples to a pump and facilitates a positive pressure within the housing cartridge. Thehousing cartridge120 preferably further includes inlet and outlet conduit ports with mounted fittings, through which thefluid conduit160 enters and exits, respectively, the housing cartridge. Thehousing cartridge120 is preferably of unitary construction, which increases the robustness of the airtight seal. However, the housing cartridge may alternatively be composed of multiple separate pieces joined together by fasteners, epoxy, a welding process, and/or any suitable joining process. In this variation, the joints between the separate housing cartridge pieces are preferably sealed with a welding process, gasket, or sealant to make thehousing cartridge120 airtight sealed. Similar sealing processes are preferably used to seal the conduit ports, and any other openings in the housing cartridge. The sealing limits exposure of a user to the fluid within the tubing and the housing cartridge, by not requiring contact between the user and the fluid during removal of the housing cartridge from the fluid pump. The sealing also limits fluid that is potentially lost in a failure such as a tubing leak. As shown inFIGS. 1A and 1B, thehousing cartridge120 preferably includes a generally round portion, and has a width that is greater than its depth. The round portion preferably provides clearance for the rotation of theframe130. The depth of thehousing cartridge120 is preferably deep enough to accommodate the length of the plurality ofrollers140 on theframe130, but not too deep, to avoid excess space in which thefluid conduit160 may wander along the length of and/or slip off the plurality ofrollers140 during pump operation. An overall smaller housing cartridge volume will also decrease noise and vibration produced by thevacuum pump180 and the fluid pump. Thehousing cartridge120 is preferably made of plastic, and more preferably a transparent plastic such as polycarbonate that allows an operator to monitor the operation of the pump head components inside thehousing cartridge120 and increase the likelihood of a quick response to a malfunction, such as a fluid conduit leak. However, the housing cartridge may be made of any suitable material with low magnetic permeability (low degree of magnetization in a magnetic field), or any suitable material. Thehousing cartridge120 is preferably injected molded, but may alternatively be machined on a mill, casted, or created through any suitable manufacturing process. In one variation, thehousing cartridge120 is removable for disposal and/or recycling. In another variation, thehousing cartridge120 is removable for refurbishing and reuse, during which consumable parts such as thefluid conduit160 are replaced and/or repaired, and thehousing cartridge120 and its pump head contents are preferably reassembled to an appropriate standard for use as a replacement housing cartridge.
• Theframe130 of the preferred embodiment functions to support a plurality ofrollers140 and provide the movement of a plurality ofrollers140 along a substantial length of thefluid conduit160. Theframe130 is preferably enclosed in thehousing cartridge120 and is operatively coupled to the motor force of the pump motor no through the non-contact coupling means150, such that the motor force induces rotation of theframe130. Theframe130 preferably includes a plurality ofrollers140. As shown inFIGS. 1 and 3, therollers140 are preferably distributed in a plane around theframe130, preferably extend generally parallel to the axis of rotation of the frame, and preferably are equally spaced apart to form the vertices of a regular polygon. For example, theframe130 may include three rollers arranged at the vertices of an equilateral triangle. As theframe130 rotates, the plurality ofrollers140 preferably move in a generally circular path. However, the number and arrangement ofrollers140 on theframe130 may depend on the specific application. For example, therollers140 may be arranged in an irregular distribution such that the rollers travel in a noncircular path. Each of therollers140 is preferably mounted for free rotation about its own axis, such that as therollers140 move along thefluid conduit160 and do not produce a significant amount of friction on the fluid conduit. The rollers may have a low friction coating or lubricant to further reduce the amount of friction thefluid conduit160, which may reduce degradation of the fluid conduit and increase the useful life of the fluid conduit.
• The drive coupling means150 of the preferred embodiment functions to transmit the motor force to theframe130, thereby inducing rotation of the frame during operation of the fluid pump. The drive coupling means150 is preferably one of several variations. In a first variation, the drive coupling means is a non-contact coupling means. The non-contact coupling means preferably includes a magnetic coupler with afirst mating portion152 and asecond mating portion154 magnetically attracted to thefirst mating portion152. Thefirst mating portion152 of the magnetic coupler is preferably connected to the rotor of the pump motor no, and thesecond mating portion154 of the magnetic coupler is preferably connected to theframe130. Because the first and second mating portions of the magnetic coupler are magnetically attracted, movement of the pump motor rotor is tracked by the frame, such that rotation and motor force of the pump motor is transmitted into rotation of theframe130. Since the magnetic field of the magnetic coupling preferably passes through the material of the housing cartridge, the magnetic coupler allows thehousing cartridge120 to be self-contained without the need for additional mechanical drive coupling between thepump motor110 and theframe130 that would complicate the coupling between thepump motor110 andhousing cartridge120. This simplifies the removable coupling between the housing cartridge and pump motor, in that thehousing cartridge120 is preferably interchangeable with a quick, drop-in replacement. The magnetic coupler preferably includes permanent magnets for reliable drive coupling. However, the magnetic coupler may alternatively include electromagnets that can be controlled to selectively provide the magnetic attraction forming the drive coupling, which may have certain advantages in some applications. For example, since removing electric current to an electromagnetic drive coupling removes the magnetic field, such selective decoupling of theframe130 and pump motor no may be useful in quick shut-off situations, or to facilitate quick removal of thehousing cartridge120 for replacement of the housing cartridge.
• The magnetic coupler is preferably one of several variations. In a first variation, as shown inFIG. 1, the magnetic coupler is amagnetic disc coupler156, in which thefirst mating portion152′ is a first magnetic disc and thesecond mating portion154′ is a second magnetic disc that is magnetically attracted to the first disc. In a second variation, as shown inFIG. 2, the magnetic coupler is a magnetic coaxial coupling158, in which thefirst mating portion152″ andsecond mating portion154″ are coaxial, magnetically attracted nested hubs. In a third variation, the magnetic coupler includes magnetic shielding that modulates and directs the magnetic field to induce rotation of theframe130. In this variation, magnetic shielding is preferably made of a material that has high magnetic permeability and high magnetic saturation to enable the magnetic shielding to easily reroute magnetic field lines. The magnetic shield preferably includes at least one opening or other geometric relief of the rerouting of magnetic field lines. The magnetic shielding is preferably coupled to thepump motor110 and positioned between the first and second mating portions of the magnetic coupler. As the pump motor rotor rotates, the magnetic shielding rotates, and the opening of the magnetic shielding through which magnetic attraction is not blocked rotates, thereby allowing theframe130 of the fluid pump to track the rotation of thepump motor110. In any of these variations, the magnetic coupler may alternatively include first and second mating portions of identical poles, such that the first and second mating portions are magnetically repulsive and the movement of the pump motor rotor repels, or “pushes”, theframe130 into rotation. However, the magnetic coupler may be a combination of these variations and/or of additional variations that incorporate magnetic force as a drive coupling means150. Furthermore, the non-contact drive coupling means may be any suitable indirect coupling means that transmits the motor force into a rotation of theframe130.
• In a second variation, as shown inFIG. 3, the drive coupling means150 between theframe130 and the pump motor no includes a direct contact coupling means between theframe130 and the pump motor, such as adrive shaft153 or flexible drive coupling. The drive coupling means150 may include keyways or other features that enhance the robustness of the drive coupling means between theframe130 and thepump motor110.
• In a third variation, the drive coupling means150 is between theframe130 and a manual actuator. In this variation, the manual actuator is a hand crank, a hand pump, or any suitable hand operable actuator that may be coupled to the frame to induce rotation of the frame.
• Other embodiments may incorporate a combination of the variations of non-contact and contact coupling means. In any of these variations, as shown inFIG. 3, the drive coupling means150 may include a torque limiting feature orcoupling device151 that provides a fail-safe feature of the fluid pump. The drive coupling means150 of the first variation inherently includes a torque limiting feature, since the magnetic forces can only couple the two mating portion with a limited force. The torque limitingcoupling device151 may include a torque-limiting clutch that slips and/or separates the coupling at an overload above a certain predetermined level of torque to avoid driving the fluid pump at an excessive level of torque. For example, the torque-limiting clutch may be an overload clutch (which disengages and remains disengaged until re-engaged manually or with other devices), a ratchetting clutch (which disengages and re-engages within any of a number of segments around the circumference of the clutch), or a synchronized clutch (which disengages and re-engages at the same point around the circumference of the clutch).
• Thefluid conduit160 of the fluid pump functions to carry fluid flow through the fluid pump. As shown inFIGS. 4A and 5A, thefluid conduit160 is preferably wrapped under tension around at least one of the plurality of rollers140 (and, more preferably, around most or all of the rollers140). Thefluid conduit160 preferably includes aninlet region162, abody region164, and anoutlet region166. Thefluid conduit160 preferably facilitates flow from theinlet region162 to theoutlet region166. When the fluid pump is in operation, fluid flows into theinlet region162 of the fluid conduit from the patient or a venous reservoir (which preferably includes blood ultimately from the blood circulation of the patient, but may alternatively be from a blood transfusion or any suitable source). As the plurality ofrollers140 advance across the fluid conduit, isolated fluid is captured in a region of the fluid conduit between a pair of adjacent rollers, expanding the fluid conduit. As rotation of theframe130 causes the plurality ofrollers140 to rotate and advance further along the fluid conduit, the isolated fluid is shuttled from theinlet region162 to thebody region164, and further into and out of theoutlet region166.
• Thefluid conduit160 preferably operates in at least two modes: a filledmode172 and acollapsed mode174. As shown inFIG. 4B, in the filledmode172, the cross section of at least a portion of thefluid conduit160 is expanded by the fluid, and rotation of theframe130 causes the plurality ofrollers140 to compress thefluid conduit160 at subsequent intervals, thereby driving the fluid to theoutlet region166 with a peristaltic movement. Thefluid conduit160 is in the filledmode172 when fluid is supplied to theinlet region162 at a pressure above the pressure outside the fluid conduit (e.g., above the vacuum level formed in the housing cartridge120). When thefluid conduit160 is in the filledmode172, the fluid pressure within thefluid conduit160 may be any pressure within a range of pressures, and flow rate preferably at least partially varies with the fluid pressure. At a characteristic fluid pressure, the fluid preferably slips past the rollers such that the fluid pressure does not further increase. This lack of increase in fluid pressure effectively limits the pumping power of the fluid pump, which may lessen danger to the patient or other fluid devices that lie downstream of the fluid pump. The lack of increase also lowers shear forces on the fluid conduit and decreases the likelihood of rupture of the fluid conduit. As shown inFIG. 5B, in thecollapsed mode174, the cross section of at least a portion of thefluid conduit160, such as theinlet region162, is closed and prevents fluid flow towards theoutlet region166. Thefluid conduit160 is preferably in thecollapsed mode174 when the pressure inside the fluid conduit is equal to the pressure outside the fluid conduit (e.g., equal to the pressure level formed in the housing cartridge120). When thefluid conduit160 is in thecollapsed mode174, the fluid pump cannot generate suction greater (cannot generate more negative pressure) than the pressure level formed in thehousing cartridge120. Therefore, the pressure level in thehousing cartridge120 preferably sets the limit of suction that the fluid pump provides, and preferably is set to a level that avoids cavitation and hemolysis of the patient and/or damage to downstream components of the fluid pump or other equipment. The presence of the vacuum assists drainage of the fluid conduit, and also preferably enables operation of the fluid pump in any orientation of the fluid pump and/or patient. Furthermore, when the fluid conduit is in thecollapsed mode174, the plurality ofrollers140 do not pump any contents of the fluid conduit, but merely pass over the closed, flattened fluid conduit until the fluid conduit is in the filledmode172. The transition between thecollapsed mode174 and the filledmode172 occurs when pressure of the fluid supplied to theinlet region162 is above the vacuum level in thehousing cartridge120. In other words, the blood volume supplied to theinlet region162 volume must be above a certain volume (“prime volume”) for the fluid conduit to transition to the filledmode172. Conversely, the transition between the filledmode172 to thecollapsed mode174 occurs when blood flow from the patient or venous reservoir into the fill region of thefluid conduit160 slows. As the pressure of the fluid supplied to the fill region decreases, thefluid conduit160 begins to collapse, as blood flow decreases in proportion to the decreased filling of the fill region. The fluid conduit may also operate in an occluded mode when the pressure within the fluid conduit is greater than the pressure outside the fluid conduit, in which the fluid conduit is at least partially open at the point of contact with a roller, such that fluid flow in the pump is either completely prevented, partially restricted, or reversed. The flow rate of the fluid pump is preferably dependent on revolutions per minute (RPM) of theframe130, and on fluid filling pressure in the fill region of thefluid conduit160.
• Thefluid conduit160 is preferably made of medical-grade polyurethane, and more preferably from a profile extrusion of thermoplastic polyurethane for durability and greater strength and toughness than other thermoset materials. However, the fluid conduit may be made of any suitable material. The extrusion is preferably shaped in a secondary heat biasing process that optimizes the filling characteristics of the pump. In this secondary process, the profile of thefluid conduit160 is preferably formed to be as flat as possible, while maintaining two characteristics: (1) sharp interior corners that minimize wear and fatigue by allowing thefluid conduit160 to completely flatten at the roller locations without inducing high cyclical bending stresses along the edges of the fluid conduit; and (2) maintaining additional material on the edges that increases durability of thefluid conduit160. Thefluid conduit160 may be further treated to include an internal coating of heparin, an anticoagulant, to reduce the tendency of blood clots as blood passes through the fluid pump. The extrusion is preferably cut to length and wrapped around the plurality ofrollers140 in factory assembly of thehousing cartridge120. Fixtures are preferably used to obtain a consistent length offluid conduit160, and to ensure that uniform tension is applied as the fluid conduit is wrapped around the plurality ofrollers140. Apolyurethane inlet tube168 is preferably radiofrequency (RF) welded to theinlet region162 of the fluid conduit and attached to a mounting fitting that is ultraviolet (UV) light bonded to thehousing cartridge120. Similarly, apolyurethane outlet tube170 is preferably RF welded to theoutlet region166 of the fluid conduit and attached to a second mounting fitting that is UV bonded to thehousing cartridge120. As shown inFIGS. 3 and 4, the inlet and outlet tubes are preferably mounted adjacent to one another on thehousing cartridge120. In some preferred embodiments, thefluid conduit160 may have the geometry and construction of that described in U.S. Pat. No. 5,486,099 entitled “Peristaltic pump with occlusive inlet” or in U.S. patent application Ser. No. 12/095,733 entitled “Pulsatile rotary ventricular pump”, which are both incorporated in their entirety by this reference.
• In one very specific example of the fluid pump intended for a pediatric patient weighing less than 25 kilograms, the fluid pump provides a blood flow rate of 0-2.5 liters/minute. The pump motor is approximately 5.3 inches in diameter, the frame is approximately 3.25 inches in diameter, and the combined depth of the housing cartridge and pump motor is preferably approximately 3.1 inches. The frame includes three rollers distributed at the vertices of an equilateral triangle. The fluid conduit has a priming volume of less than 25 milliliters, and has a ⅜″diameter inlet tube168 and a ¼″ diameter outlet tube welded to the fluid conduit.
• The fluid pump may further include a controller that allows an operator to interact with, monitor, and control the fluid pump. The controller preferably includes a graphical user interface, a touch screen or buttons, an ultrasonic flow meter, a bubble detector, pressure sensors, a vacuum controller, and any suitable hardware. The controller preferably further includes an optical sensor located at the bottom end of the housing cartridge, which may be used to detect an obstruction such as pooling fluid levels in the bottom of the housing cartridge, which suggests a leakage in the fluid conduit. The controller preferably includes an audio and/or visual device to alert the user of the possible leak. The controller preferably also allows the user to define limits for triggering an alarm regarding various crucial characteristics of the fluid pump, such as flow rate and pressure.
2. Method of Supplying a Plurality of Housing Cartridges
• As shown inFIG. 6, themethod200 of supplying a plurality of housing cartridges preferably includes the steps of: manufacturing a sealed housing cartridge S210 that includes manufacturing a rotating frame, a plurality of rollers arranged on the frame, and a fluid conduit wrapped around the plurality of rollers; tensioning the fluid conduit to a desired amount of tension S220; positioning the plurality of rollers to minimize the path length of the conduit around the rollers, thereby relieving at least a portion of tension in the fluid conduit S230. The method may optionally further include setting the internal pressure of the housing cartridge to a desired pressure level S240. Themethod200 preferably further includes step S250, which includes repeating steps S210-S240 for supplying a plurality of housing cartridges, and step S260, which includes distributing the plurality of housing cartridges. The housing cartridge is preferably interchangeable with other housing cartridges in a fluid pump, and adapted to removably couple to a pump motor in the fluid pump.
• Step S210, which includes manufacturing a sealed housing cartridge, preferably includes the manufacturing steps described above, to form a rotating frame, a plurality of rollers arranged on the frame, and a fluid conduit wrapped around the plurality of rollers. The rotating frame preferably has a portion of a drive coupling that mates with another portion of the drive coupling connected to the pump motor.
• Step S220, which includes tensioning the fluid conduit to a desired amount of tension, functions to tighten the fluid conduit around the rollers to a suitable tightness setting to limit the maximum amount of fluid pressure that, when the housing cartridge is coupled to the pump motor, limits the maximum amount of fluid pressure that can be generated in the fluid conduit. S220 preferably includes wrapping the fluid conduit around a fixture that ensures that uniform tension is applied as the fluid conduit is wrapped around the plurality of rollers.
• Step S230, which includes positioning the plurality of rollers, functions to relieve tension in the fluid conduit to reduce creep that a fluid conduit continuously loaded in tension may experience over a long period of time such as during storage and/or shipping. Step S230 preferably positions the plurality of rollers such that the path length of the conduit around the rollers is minimized. Step S230 preferably includes rotating the frame, which preferably rotates the orientation of the plurality of rollers such that the path length of the fluid conduit around the rollers is minimized. For example, as shown inFIG. 6C, in a housing cartridge having a frame with three rollers equally distributed around the circumference of the frame, the frame is preferably rotated such that all three rollers are in contact with the fluid conduit. In some embodiments, the frame may have many rollers, such that there is no rotational orientation of the frame in which all the rollers are in contact with the fluid conduit. In these embodiments, it may be sufficient that the rollers are positioned to allow as many rollers as possible to contact the fluid conduit. Step S230 may further include locking the positions of the rollers, such as with a latch or other suitable mechanism that sets the rotational position of the frame.
• Step S240, which includes setting the internal pressure of the housing cartridge to a desired pressure level S240, functions to limit the amount of suction that the fluid pump provides, when the housing cartridge is coupled to the pump motor. Through a pressure control port on the housing cartridge, the internal pressure is preferably set to a level that avoids cavitation and hemolysis of the patient and/or damage to downstream components of the fluid pump or other equipment. The internal pressure of the housing cartridge is preferably set to a vacuum, but may alternatively be set to a positive pressure. After setting the internal pressure of the housing cartridge, the pressure control port may be sealed or eliminated.
• Step S250, which includes repeating steps S210-S240 for a plurality of housing cartridges preferably increases consistency between housing cartridges that are distributed, such that a fluid pump that is compatible with the distributed housing cartridges performs more reliably and consistently between interchanged housing cartridges.
• Step260, which includes distributing the plurality of housing cartridges, functions to provide a series of cartridges to a customer, such as a hospital. The series of cartridges are preferably provided in a case, such as a case of 24 cartridges, but may be provided in any suitable number or as a single cartridge on an as-needed basis.
• As a person skilled in the art will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the preferred embodiments of the invention without departing from the scope of this invention defined in the following claims.

Claims (28)

1. A modular fluid pump comprising:

a pump motor that provides a motor force;

a housing cartridge removably coupled to the pump motor, wherein the housing cartridge is interchangeable with a replacement housing cartridge;

a frame enclosed in the housing cartridge and having a plurality of rollers arranged on the frame;

a non-contact drive coupling means for transmitting the motor force from the pump motor to the frame thereby inducing rotation of the frame; and

a fluid conduit, wrapped under tension around at least one of the plurality of rollers, that facilitates fluid flow from an inlet region of the fluid conduit to an outlet region of the fluid conduit, wherein rotation of the frame causes the plurality of rollers to compress the fluid conduit at subsequent intervals, thereby driving fluid to the outlet region with a peristaltic movement.

2. The modular fluid pump ofclaim 1, wherein the housing is airtight sealed and includes a port that facilitates adjustment of the pressure within the housing cartridge.

3. The modular fluid pump ofclaim 1, wherein the non-contact drive coupling means includes a magnetic coupler.

4. The modular fluid pump ofclaim 3, wherein the magnetic coupler is a magnetic disc coupler including a first disc and a second disc magnetically attracted to the first disc, wherein the first disc is connected to the pump motor and the second disc is connected to the frame.

5. The modular fluid pump ofclaim 4, wherein at least one of the first and second discs of the magnetic disc coupler is enclosed in an airtight seal.

6. The modular fluid pump ofclaim 3, wherein the magnetic coupler is a magnetic coaxial coupler including a first portion and a second portion magnetically attracted to the first portion, wherein the first portion is connected to the pump motor and the second portion is connected to the frame.

7. The modular fluid pump ofclaim 6, wherein at least one of the first and second portions of the magnetic coaxial coupler is enclosed in an airtight seal.

8. The modular fluid pump ofclaim 1, wherein the pump motor is coupled to a motor housing having a mating surface that mates with the housing cartridge.

9. The modular fluid pump ofclaim 8, wherein the housing cartridge slides onto the mating surface of the motor housing.

10. The modular fluid pump ofclaim 1, wherein the fluid conduit operates in the following modes:

a filled mode, wherein the cross section of at least a portion of the fluid conduit is expanded by the fluid and allows fluid flow toward the outlet region during rotation of the frame; and

a collapsed mode, wherein the cross section of at least the inlet region is closed and prevents fluid flow toward the outlet region during rotation of the frame.

11. The modular fluid pump ofclaim 10, wherein fluid flow in the fluid conduit decreases in proportion to decreased filling pressure at the inlet region.

12. The modular fluid pump ofclaim 10, wherein the housing is airtight sealed and includes a vacuum port that facilitates formation of a vacuum within the housing.

13. A housing cartridge for a modular fluid pump system that includes a pump motor providing a motor force, the housing cartridge comprising:

a frame enclosed in the housing cartridge;

a plurality of rollers arranged on the frame;

a second portion of a non-contact coupler connected to the frame, wherein the second portion of the non-contact drive coupler mates with a first portion of the non-contact drive coupler, such that the non-contact drive coupler transmits the motor force to the frame thereby inducing rotation of the frame; and

a fluid conduit, wrapped under tension around at least one of the plurality of rollers, that facilitates fluid flow from an inlet region of the fluid conduit to an outlet region of the fluid conduit, wherein rotation of the frame causes the plurality of rollers to compress the fluid conduit at subsequent intervals, thereby driving fluid to the outlet region with a peristaltic movement;

wherein the housing cartridge is interchangeable with a replacement housing cartridge in the modular fluid pump system.

14. The housing cartridge ofclaim 13, wherein the housing cartridge is airtight sealed and includes a pressure control port that facilitates adjustment of the pressure within the housing cartridge.

15. The housing cartridge ofclaim 15, wherein the non-contact drive coupler includes a disc that is connected to the frame and that is magnetically attracted to another disc connected to the pump motor.

16. The housing cartridge ofclaim 15, wherein the non-contact drive coupler includes a portion that is connected to the frame and that is magnetically attracted and co-axially aligned with another portion connected to the pump motor.

17. The modular fluid pump ofclaim 15, wherein the fluid conduit operates in the following modes:

a filled mode, wherein the cross section of at least a portion of the fluid conduit is expanded by the fluid and allows fluid flow toward the outlet region during rotation of the frame; and

a collapsed mode, wherein the cross section of at least the inlet region is closed and prevents fluid flow toward the outlet region during rotation of the frame.

18. A modular fluid pump comprising:

a pump motor that provides a motor force;

a housing cartridge removably coupled to the pump motor, wherein the housing cartridge is interchangeable with a replacement housing cartridge, wherein the housing cartridge is airtight sealed and includes a pressure control port adapted to facilitate adjustment of the pressure within the housing cartridge;

a frame, enclosed in the housing cartridge and having a plurality of rollers arranged on the frame;

a drive coupling means for transmitting the motor force from the pump motor to the frame thereby inducing rotation of the frame; and

a fluid conduit, wrapped under tension around at least one of the plurality of rollers, that facilitates fluid flow from an inlet region of the fluid conduit to an outlet region of the fluid conduit, wherein the fluid conduit operates in the following modes:

a filled mode, wherein the cross section of at least a portion of the fluid conduit is expanded by the fluid, wherein rotation of the frame causes the plurality of rollers to compress the fluid conduit at subsequent intervals, thereby driving the fluid to the outlet region with a peristaltic movement; and

a collapsed mode, wherein the cross section of at least the inlet region is closed and prevents fluid flow towards the outlet region.

19. The fluid pump ofclaim 18, wherein the pressure control port is a vacuum port that facilitates formation of a vacuum.

20. The fluid pump ofclaim 18, wherein the drive coupling means includes a torque-limiting mechanism.

21. The fluid pump ofclaim 18, wherein the drive coupling means includes a magnetic disc coupler including a first disc and a second disc magnetically attracted to the first disc, wherein the first disc is coupled to the pump motor and the second disc is coupled to the frame.

22. The fluid pump ofclaim 18, wherein the drive coupling means includes a magnetic coaxial coupler including a first portion and a second portion magnetically attracted to the first portion, wherein the first portion is coupled to the pump motor and the second portion is coupled to the frame.

23. The fluid pump ofclaim 18, wherein the fluid conduit further operates in an occluded mode, wherein the pressure within the fluid conduit is greater than the pressure in the housing cartridge, wherein the fluid conduit is at least partially open at the point of contact with at least one of the plurality of rollers.

24. A method of supplying a housing cartridge, comprising:

manufacturing a sealed housing cartridge including a rotating frame, a plurality of rollers arranged the frame, and a fluid conduit wrapped around the plurality of rollers;

tensioning the fluid conduit to a desired amount of tension; and

positioning the plurality of rollers to minimize the path length of the fluid conduit around the rollers, thereby removing at least a portion of tension in the fluid conduit.

25. The method ofclaim 24, wherein the step of positioning the plurality of rollers includes rotating the frame.

26. The method ofclaim 24, further comprising the step of setting the internal pressure of the housing cartridge to a desired pressure level.

27. The method ofclaim 26, wherein the step of setting the internal pressure of the housing cartridge includes forming a vacuum within the housing cartridge.

28. The method ofclaim 24, further comprising repeating all of the steps to create a series of housing cartridges and then distributing the series of housing cartridges.

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