pump

Abstract

The rotary pump (200) comprises a housing (205) having an inner surface (220) defining a cavity in which a first fluid port (210) and a second fluid port (215) and a rotor (225) are located, the rotor comprising a housing engaging surface area (235) which forms a sealing interference fit with the inner surface of the housing and a surface recess (250) which forms with the inner surface of the housing a fluid carrying chamber which carries fluid from the first fluid port to the second fluid port in response to rotation of the rotor, and a plurality of resiliently deformable diaphragms (255) providing a portion of the inner surface of the housing, each diaphragm comprising a rotor engaging surface (257) and a rear surface (260), the rotor engaging surfaces being urged into contact with the rotor by action of a pressure applying means (265) acting against the rear surface.

Description

[Technical field]

[0001] The present invention relates to pumps, and in particular to rotary pumps. [Background technology]

[0002] It is known to provide a pump formed by a housing having an inlet and an outlet for a fluid, containing a rotor with at least one surface recess forming, with an inner surface of the rotor, a chamber that conveys the fluid from the inlet to the outlet in response to rotation of the rotor. A flexible diaphragm is provided on or as part of the housing, located between the inlet and the outlet, to prevent the fluid from passing from the outlet to the inlet. The diaphragm is urged into engagement with the rotor by pressure means, which can take many forms such as a block of resilient material, a resilient tube of material, a spring, or hydraulic or pneumatic pressure. A pump of this general type is disclosed in International Patent Application No. WO2006 / 027548.

[0003] Because such pumps comprise a discrete number of chambers formed by recesses in the rotor surface that convey fluid from an inlet to an outlet, the resulting liquid flow tends to be pulsed, with periods of no flow and periods of high flow. This can be harmful in some applications, for example when administering medicine to a patient, where the pulsating flow can be uncomfortable. It is an object of the present invention to provide a pump with an improved flow profile.

[0004] Attempts have been made to reduce pulsation of fluid flow in pumps, such as the rotary infusion pump described in International Patent Application WO2011 / 119464. This document discloses a pump having a housing containing a rotor, the rotor including a first ring of surfaces forming a channel with the housing and a second ring of surfaces forming a channel with the housing. The first and second rings are radially offset to attenuate pulsation of fluid flow through the pump.

[0005] There is always a desire to provide smaller pumps with higher throughput. It is an objective of the preferred embodiment of the present invention to provide a rotary pump with higher throughput for a given size. It is also desirable to improve flow rate to power efficiency.

[0006] Furthermore, in many applications it is important to be able to sterilize the pumps so that they may be used as part of a single-use system. It is an object of the present invention to provide a pump that can be more easily sterilized.

[0007] It is an object of the preferred embodiments of the present invention to provide a rotary pump that provides essentially continuous flow. Continuous flow as used herein is defined as flow where there are no periods of no fluid flow. Continuous flow does not necessarily mean that there is a constant flow rate, but rather that there may be some fluctuations in the flow rate, provided that there is always a positive flow of fluid while the pump is operating and delivering fluid. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2006 / 027548 [Patent Document 2] International Publication No. 2011 / 119464 Summary of the Invention [Means for solving the problem]

[0009] Aspects of the invention described herein may be useful alone or in combination with other aspects described herein.

[0010] According to a first aspect of the invention, there is provided a pump comprising: a housing having an inner surface defining a first fluid port and a second fluid port and a cavity in which a rotor is located; a rotor rotatably mounted within the housing and having a longitudinal axis of rotation, the rotor comprising a housing engaging surface area forming a sealing interference fit with the inner surface of the housing and a surface recess forming with the inner surface of the housing a fluid carrying chamber for carrying fluid from the first fluid port to the second fluid port in response to rotation of the rotor; and a plurality of resiliently deformable diaphragms each providing a portion of the inner surface of the housing, each diaphragm comprising a rotor engaging surface and a rear surface opposite the rotor engaging surface, the rotor engaging surface of each diaphragm being urged into contact with the rotor by action of a pressure means acting against the rear surface of the diaphragm, the number of resiliently deformable diaphragms exceeding the number of surface recesses on the rotor. a rotor comprising an elongated body and a drive shaft, the elongated body being generally hollow and comprising separate first and second rotor cavities, the first rotor cavity having an opening at a first end of the rotor and the second rotor cavity having an opening at a second end of the rotor, the rotor body further comprising a first opening between the first rotor cavity and the surface recess and a second opening between the surface recess and the second rotor cavity, the pump arranged such that when the rotor body is located within the housing cavity, the first fluid port is in fluid flow communication with the first rotor cavity through the opening at the first end of the rotor and the second fluid port is in fluid flow communication with the second rotor cavity through the opening at the second end of the rotor, and the pump arranged such that as the rotor rotates at least one of the resiliently deformable diaphragms always bisects the first and second openings on the rotor surface recess.

[0011] According to a second aspect of the invention there is provided a pump comprising: a housing having an inner surface defining a cavity in which a rotor is located, a rotor rotatably mounted within the housing, the rotor having a longitudinal axis of rotation and a housing engaging surface area forming a sealing interference fit with the inner surface of the housing, and a surface recess forming with the inner surface of the housing a fluid carrying chamber for carrying fluid from the first fluid port to the second fluid port in response to rotation of the rotor, the rotor being twisted about its longitudinal axis of rotation such that the first and second ends of the rotor are rotationally offset by at least 10 degrees relative to one another; and a resiliently deformable diaphragm providing a portion of the inner surface of the housing, the diaphragm having a rotor engaging surface and a rear surface opposite the rotor engaging surface, the rotor engaging surface of the diaphragm being urged into contact with the rotor by action of a pressure means acting against the rear surface of the diaphragm. and a resiliently deformable diaphragm adapted to be elastically deformed on the rotor surface recess, the rotor comprising an elongated body and a drive shaft, the body being generally hollow and comprising separate first and second rotor cavities, the first rotor cavity having an opening at a first end of the rotor and the second rotor cavity having an opening at a second end of the rotor, the rotor body further comprising a first opening between the first rotor cavity and the surface recess and a second opening between the surface recess and the second rotor cavity, the pump arranged such that when the rotor body is located within the housing cavity, the first fluid port is in fluid flow communication with the first rotor cavity through the opening at the first end of the rotor and the second fluid port is in fluid flow communication with the second rotor cavity through the opening at the second end of the rotor, and the pump arranged such that as the rotor rotates the resiliently deformable diaphragm always bisects the first opening and the second opening on the rotor surface recess.

[0012] According to a third aspect of the invention there is provided a pump comprising: a housing having an inner surface defining a cavity in which a rotor is located, a rotor rotatably mounted within the housing, the rotor having a longitudinal axis of rotation and comprising a housing engaging surface area forming a sealing interference fit with the inner surface of the housing and a surface recess forming with the inner surface of the housing a fluid carrying chamber for carrying fluid from the first fluid port to the second fluid port in response to rotation of the rotor; and a resiliently deformable diaphragm providing a portion of the inner surface of the housing, the diaphragm comprising a rotor engaging surface and a rear surface opposite the rotor engaging surface, the rotor engaging surface of the diaphragm being urged into contact with the rotor by action of a pressure means acting against the rear surface of the diaphragm, a linear rib either upstanding from or acting against the rear surface of the resiliently deformable diaphragm, the linear rib being offset from the longitudinal axis of the rotor by at least 10 degrees. and a resiliently deformable diaphragm angled relative to a counter-rotation axis; a rotor comprising an elongated body and a drive shaft, the body being generally hollow and comprising separate first and second rotor cavities, the first rotor cavity having an opening at a first end of the rotor and the second rotor cavity having an opening at a second end of the rotor, the rotor body further comprising a first opening between the first rotor cavity and the surface recess and a second opening between the surface recess and the second rotor cavity, the pump arranged such that when the rotor body is located within the housing cavity, the first fluid port is in fluid flow communication with the first rotor cavity through the opening at the first end of the rotor and the second fluid port is in fluid flow communication with the second rotor cavity through the opening at the second end of the rotor, and the pump is arranged such that as the rotor rotates the resiliently deformable diaphragm always bisects the first opening and the second opening on the rotor surface recess.

[0013] Preferably, in all aspects of the invention, the housing comprises a resilient material, such as polypropylene, polyethylene, thermoplastic polyurethane, or rubber. The first fluid port and / or the second fluid port may extend from the housing. If the first fluid port and / or the second fluid port extend from the housing, the first and / or second fluid port are preferably molded with the housing.

[0014] The rotor may be made from a rigid material such as stainless steel, polyetheretherketone (PEEK), high density polyethylene (HDPE), or polycarbonate. The selection of materials for the housing and rotor are interdependent and should be selected so that there is a low coefficient of friction between the contacting surfaces of the housing and rotor.

[0015] According to all aspects of the invention, the housing may comprise a single unit providing an inner surface, a first fluid port and a second fluid port, and optionally one or more elastically deformable diaphragms, that define a cavity in which the rotor is located. Alternatively, the housing may provide an inner surface, and optionally one or more elastically deformable diaphragms, that define a cavity in which the rotor is located, and may be used in conjunction with a first and / or second separate end cap to close the cavity in which the rotor is located. In this embodiment, the first and / or second fluid ports may be provided in the housing or in the separate end caps.

[0016] A pump according to the second or third aspect of the present invention may comprise one elastically deformable diaphragm.

[0017] Alternatively, a pump according to the second or third aspect of the invention may comprise a plurality of elastically deformable diaphragms. A pump according to any aspect of the invention may comprise any suitable number of elastically deformable diaphragms. In a preferred embodiment of any aspect of the invention, the pump comprises two elastically deformable diaphragms. In an alternative preferred embodiment of any aspect of the invention, the pump comprises three elastically deformable diaphragms. When the pump comprises a plurality of elastically deformable diaphragms, they are preferably arranged equidistantly about the circumference of the rotor.

[0018] In all aspects of the invention, one or all of the elastically deformable diaphragms are preferably provided by sections of a housing that are fabricated to a thickness small enough to provide the required elasticity of deformation. For example, the elastically deformable diaphragms are provided by sections of a housing that are 1 mm or less, preferably 0.5 mm or less, and in some embodiments less than 0.1 mm thick. In this embodiment, the housing is preferably made from an elastic thermoplastic or thermoset material, and each elastically deformable diaphragm is integral with the housing.

[0019] Alternatively, in all aspects of the invention, one or all of the elastically deformable diaphragms may comprise a section of elastically deformable elastomeric material that is sealingly attached to or co-molded with the housing. The separate diaphragm should be attached to the housing to create a sealed continuous rotor-engaging surface as the inner surface of the housing, and preferably comprises an elastomeric material such as a thermoplastic elastomer (TPE) or a thermoplastic polyurethane (TPU). When the diaphragm is provided by a separate elastically deformable elastomeric material, the housing may comprise a resilient material, for example polypropylene, polyethylene, thermoplastic polyurethane, or rubber, or the housing may be made of a rigid material.

[0020] In use, according to all aspects of the invention, each diaphragm forms a fluid tight contact between the rotor-engaging surface of the diaphragm and the rotor surface, and further, the resiliently deformable nature of each diaphragm means that, in use, each diaphragm conforms to the contoured surface of the rotor such that it is operable to displace fluid from the fluid-carrying chamber as the rotor rotates.

[0021] In an embodiment of the first and second aspect of the invention, the or each of the elastically deformable diaphragms may comprise linear ribs projecting from a rear face thereof. Alternatively, the ribs may be provided on a spring means providing a pressure means arranged such that, in use, it acts against a rear face of the or each of the diaphragms. In an embodiment of the first or second aspect of the invention, the ribs extend along the entire length of the diaphragm in a direction parallel to the longitudinal axis of rotation of the rotor. Alternatively, in an embodiment of the first or second aspect of the invention, the linear ribs extend along the entire length of the diaphragm and are angled by at least 10 degrees to the longitudinal axis of rotation of the rotor.

[0022] In all aspects of the invention, any suitable pressure means may be used to urge the rotor-engaging surface of each diaphragm into contact with the rotor. The pressure means may comprise a spring means acting against a rear face of the, or each, resiliently deformable diaphragm. For example, the pressure means may comprise a block or tube of elastic material to which pressure may be applied, urging the spring means against a rear face of the, or each, resiliently deformable diaphragm. Examples of suitable spring members are disclosed in International Patent Application No. WO2013 / 117486. Alternatively, or in addition, the pressure means may comprise a fluid applied to a rear face of the, or each, resiliently deformable diaphragm. Examples of pumps comprising a fluid applied to a rear face of a resiliently deformable diaphragm are disclosed in International Patent Application Nos. WO2010 / 122299 and WO2014 / 135563.

[0023] In embodiments of all aspects of the invention, a pump according to the invention may comprise a diaphragm chamber surrounding the rear face of the resiliently deformable diaphragm.

[0024] In all aspects of the invention, the diaphragm chambers may be provided by walls extending from the housing, preferably with a separate cap for closing the chamber. Alternatively, the diaphragm chambers may comprise separate units attached to the housing. The diaphragm chambers preferably house pressure means arranged to urge the resiliently deformable diaphragm against the rotor. Each diaphragm chamber may comprise either an open or closed chamber for locating the pressure means. The closed chambers may be hermetically sealed.

[0025] In embodiments of all aspects of the invention, the diaphragm chamber may be a closed chamber connected by a passage to the fluid flowing through the pump such that the fluid flowing through the pump provides the pressurizing means. The passage providing fluid to the diaphragm chamber may include a one-way valve to allow fluid to flow into the diaphragm chamber but not out of it. This one-way valve arrangement allows sustained pressure on the diaphragm once the diaphragm chamber is loaded with fluid, even if the direction of flow of the pump is reversed.

[0026] Alternatively, in embodiments of all aspects of the invention, the diaphragm chamber may be a closed chamber connected by a passageway to a separate fluid source, which separate fluid source provides the pressurization means.

[0027] In embodiments of all aspects of the invention, the second fluid port may extend from the diaphragm chamber. Further, if the diaphragm chamber includes a separate cap for closing the chamber, the second fluid port may extend from the cap.

[0028] In embodiments of all aspects of the invention, the diaphragm chamber surrounds only one elastically deformable diaphragm. Alternatively, individual diaphragm chambers may surround the rear surface of each of the elastically deformable diaphragms.

[0029] In alternative embodiments of all aspects of the invention, each resiliently deformable diaphragm is surrounded by a separate diaphragm chamber, and the multiple diaphragm chambers are interconnected, thereby effectively producing a single diaphragm chamber. The multiple diaphragm chambers may be interconnected by providing fluid channels between the chambers. This is particularly useful where a second fluid port of the pump extends from the diaphragm chamber and / or where fluid from a second rotor cavity provides the pressurizing means.

[0030] In all aspects of the invention, the rotor is generally cylindrical and comprises at least one recess forming a fluid carrying chamber with the inner surface of the housing. In all aspects of the invention, the surface recess is provided by a recessed area in the rotor surface. In all aspects of the invention, the surface recess preferably extends longitudinally along a majority of the axial length of the rotor. In preferred embodiments, the surface recess does not extend along the entire axial length of the rotor, but preferably extends longitudinally along substantially the entire axial length of the rotor. In embodiments in which the rotor comprises multiple recesses, the multiple recesses are distinct and do not intersect.

[0031] In embodiments of all aspects of the invention, the rotor may have a plurality of surface recesses that form, with the inner surface of the housing, a corresponding plurality of fluid carrying chambers that carry fluid from a first fluid port to a second fluid port in response to rotation of the rotor. For example, the rotor may have two surface recesses that form, with the inner surface of the housing, two fluid carrying chambers. In alternative embodiments of all aspects of the invention, the rotor may have three surface recesses that form, with the inner surface of the housing, three fluid carrying chambers. The rotor may have four surface recesses that form, with the inner surface of the housing, four fluid carrying chambers. Furthermore, the rotor may have five surface recesses that form, with the inner surface of the housing, five fluid carrying chambers. The rotors of all aspects of the invention may include any number of recesses that provide a corresponding number of fluid carrying chambers, but the more chambers, the smaller the volume of fluid that can be carried in each chamber for a given rotor diameter and length.

[0032] Preferably, where a pump according to any aspect of the invention comprises a plurality of surface recesses, the plurality of surface recesses are arranged circumferentially about the rotor. Preferably, the plurality of surface recesses are spaced equidistantly about the circumference of the rotor. In all aspects of the invention, the plurality of recesses are not arranged longitudinally along the axial length of the rotor.

[0033] In embodiments of all aspects of the invention, the rotor may have two recesses and a generally cylindrical shape with circular cross-sections at each end and an elliptical cross-section at the centre.

[0034] In alternative embodiments of all aspects of the invention, the rotor may have three recesses with a circular cross-section at each end and a generally triangular cross-section at the center. In alternative embodiments of all aspects of the invention, the rotor has four recesses with a circular cross-section at each end and a generally square cross-section at the center. In alternative embodiments of all aspects of the invention, the rotor has five recesses with a circular cross-section at each end and a generally hexagonal cross-section at the center.

[0035] Preferably, the housing-engaging surface area that forms a sealing interference fit with the inner surface of the housing constitutes the entire cylindrical surface of the rotor, except for one or more surface recesses on the rotor. Preferably, the rotor comprises a substantially cylindrical body in which one or more surface recesses are formed. The housing-engaging surface area of ​​the rotor preferably comprises cylindrical areas at each end of the rotor in which no surface recesses are formed, the cylindrical areas being connected by elongated sections of the rotor surface that separate the longitudinal extents of adjacent recesses. The cylindrical areas at the ends of the rotor and the elongated sections between adjacent recesses are connected and lie in the same cylindrical plane that defines the cylindrical surface of the rotor. The elongated sections of the rotor surface that separate adjacent recesses provide lands between adjacent recesses on the rotor surface.

[0036] In an embodiment of the second or third aspect of the invention, the pump may comprise an equal number of elastically deformable diaphragms and surface recesses on the rotor. For example, a pump according to the second or third embodiment of the invention may comprise two elastically deformable diaphragms and two surface recesses on the rotor, forming two fluid carrying chambers together with the inner surface of the housing.

[0037] In other embodiments of the second or third aspects of the invention, the number of elastically deformable diaphragms exceeds the number of surface recesses on the rotor. For example, according to all aspects of the invention, a pump may include three elastically deformable diaphragms and two surface recesses on the rotor, forming, together with the interior of the housing, two fluid carrying chambers.

[0038] Pumps with multiple diaphragms can advantageously operate at higher throughputs compared to pumps with a single diaphragm. For example, a pump with two diaphragms and a rotor with two recesses will produce twice the flow of a pump with one diaphragm and a rotor with two recesses, since each recess is emptied twice in one revolution.

[0039] In all aspects of the invention, the rotor comprises an elongated body, which is generally hollow and comprises a first rotor cavity and a second rotor cavity. The first and second rotor cavities may be arranged consecutively along the height of the rotor. Alternatively, the first and second rotor cavities may extend longitudinally along the length of the rotor and be arranged alongside one another. Preferably, the first and second rotor cavities are separated from one another by a partition wall. If the first and second rotor cavities are arranged consecutively along the length of the rotor, the partition wall preferably extends across the entire cross section of the interior of the rotor body. If the first and second rotor cavities are arranged alongside one another, the partition wall preferably extends along the entire length of the interior of the rotor body. If the partition wall extends along the entire length of the interior of the rotor body, it may be curved, staggered or angled, but the first and second rotor cavities must remain separated by the partition wall. In all embodiments, the first rotor cavity and the second rotor cavity are not in direct fluid communication.

[0040] In all aspects of the invention, the first rotor cavity has an opening at the first end of the rotor for placing the first fluid port and the first rotor cavity in direct fluid communication. In a preferred embodiment, the opening extends across substantially the entire first end of the first rotor cavity.

[0041] In all aspects of the invention, the second rotor cavity has an opening at the second end of the rotor for placing the second rotor cavity in direct fluid communication with the second fluid port. In a preferred embodiment, the opening extends across substantially the entire second end of the second rotor cavity.

[0042] In all aspects of the invention, the rotor body comprises a first opening between the first rotor cavity and the surface recess and a second opening between the surface recess and the second rotor cavity. Preferably, the first opening and the second opening are each provided by a slot in the rotor body.

[0043] In embodiments of all aspects of the invention, the rotor may include a first groove in a surface of the rotor extending along substantially the entire length of opposing longitudinal edges of the surface recess, and a second groove, wherein a first opening between the first rotor cavity and the surface recess extends along a portion of the first groove that overlies the first rotor cavity, and a second opening between the surface recess and the second rotor cavity extends along a portion of the second groove that overlies the second rotor cavity.

[0044] Preferably, in all aspects of the invention, a first opening between the first rotor cavity and the surface recess is located adjacent, and preferably contiguous with, an edge of the recess that forms a leading edge as the rotor rotates, and a second opening between the second rotor cavity and the surface recess is located adjacent, and preferably contiguous with, an opposing edge of the recess that forms a trailing edge as the rotor rotates.

[0045] In some embodiments of all aspects of the invention, the first opening between the first rotor cavity and the surface recess extends along the entire axial length of the surface recess overlying the first rotor cavity and continues through the first end of the rotor. Alternatively or additionally, in some embodiments of all aspects of the invention, the second opening between the surface recess and the second rotor cavity extends along the entire axial length of the surface recess overlying the second rotor cavity and through the second end of the rotor. In these embodiments, the first opening and / or the second opening will extend through the housing-engaging surface area at the end of the rotor. Having the first and / or second opening extend through the housing-engaging surface area at the end of the rotor advantageously means that the pumped fluid provides a lubricating and cooling effect between the housing-engaging surface area of ​​the rotor and the inner surface of the housing.

[0046] In embodiments of the first and third aspects of the invention, both the first opening and the second opening are substantially parallel to the longitudinal axis of rotation of the rotor.

[0047] In a second aspect of the invention, twisting the rotor has the effect of twisting the recesses on the rotor surface and the lands extending between the first and second rotor cavities and recesses. Where the first opening between the first rotor cavity and the surface recesses and the second opening between the surface recesses and the second rotor cavity are provided by slots in the rotor body, these slots are also angled relative to the longitudinal axis of rotation of the rotor in the direction in which the rotor is twisted. The slots and the lands between the recesses are preferably substantially parallel.

[0048] In all aspects of the invention, a first opening between the first rotor cavity and the surface recess extends along substantially the entire axial length of the surface recess overlying the first rotor cavity, and a second opening between the surface recess and the second rotor cavity extends along substantially the entire axial length of the surface recess overlying the second rotor cavity.

[0049] In all aspects of the invention, the first opening between the first rotor cavity and the surface recess and the second opening between the surface recess and the second rotor cavity may be of any suitable shape, for example the openings may be generally linear, straight, oval, elongated oval or tapered. Preferably, in all aspects of the invention, the first opening between the first rotor cavity and the surface recess extends along a leading edge of the recess, substantially parallel to the land between adjacent recesses. Preferably, in all aspects of the invention, the second opening between the second rotor cavity and the recess extends along a trailing edge of the recess, substantially parallel to the land between adjacent recesses. In both cases, the first opening and the second opening are preferably adjacent to the land.

[0050] In embodiments of all aspects of the invention comprising a plurality of surface recesses, each surface recess preferably comprises a first opening between a first rotor cavity and the surface recess, and a second opening between a second rotor cavity and the surface recess.

[0051] In all aspects of the invention, the rotor drive shaft preferably extends from a hollow interior of the rotor body. The drive shaft may be a separate component fixed to the rotor or the drive shaft may be integral with the rotor. The drive shaft preferably extends from a partition formed within the interior of the rotor body that separates the first and second rotor cavities.

[0052] In embodiments of all aspects of the invention, the rotor may be twisted about its longitudinal axis such that the first and second ends of the rotor are offset from one another by at least 10 degrees, or at least 15 degrees, or at least 20 degrees. In embodiments of all aspects of the invention, the rotor may be twisted about its longitudinal axis such that the first and second ends of the rotor are offset from one another by no more than 45 degrees, or no more than 40 degrees.

[0053] In embodiments of the third aspect of the invention, the linear ribs may be angled relative to the longitudinal axis of rotation of the rotor by at least 10 degrees, or at least 15 degrees, or at least 20 degrees. In embodiments of the third aspect of the invention, the linear ribs may be angled relative to the longitudinal axis of rotation of the rotor by no more than 45 degrees, or no more than 40 degrees.

[0054] In an embodiment of the first or second aspect of the invention, the pump may further comprise linear ribs either upstanding from or acting against the rear surface of the elastically deformable diaphragm, the linear ribs being angled to the longitudinal axis of rotation of the rotor by at least 10 degrees, or at least 15 degrees, or at least 20 degrees. In an embodiment of the first or second aspect of the invention, the pump may further comprise linear ribs either upstanding from or acting against the rear surface of the elastically deformable diaphragm, the linear ribs being angled to the longitudinal axis of rotation of the rotor by no more than 45 degrees, or no more than 40 degrees.

[0055] In an embodiment of the invention in which the rotor is twisted and the pump comprises linear ribs either protruding from or acting against the rear face of the diaphragm, the ribs being angled relative to the longitudinal axis of the rotor, the rotor is twisted in a direction opposite to the angle of the ribs.

[0056] In embodiments with multiple surface recesses, and thus multiple first openings between the first rotor cavity and the surface recesses and multiple second openings between the second rotor cavity and the surface recesses, a single first rotor cavity can simultaneously provide fluid to multiple fluid-carrying cavities through the multiple first openings, and the second rotor cavity can simultaneously receive fluid from the fluid-carrying cavities through the second openings.

[0057] Preferably, pumps according to all aspects of the present invention comprise only a single rotor.

[0058] The combination of the first and second rotor cavities, the first and second openings between the rotor cavities and the surface recesses, and the resiliently deformable diaphragms improves the consistency of the fluid flow rate provided and, in some embodiments of all of the aspects of the invention, allows the pump to be arranged to provide a continuous flow rate. Different combinations of the number of diaphragms and the number of recesses on the rotor will produce different flow profiles of the fluid through the pump.

[0059] A pump according to the first aspect of the invention with an even number of diaphragms and an odd number of fluid carrying chambers will provide continuous fluid flow.A pump according to the first aspect of the invention with an odd number of diaphragms and an even number of fluid carrying chambers will provide continuous fluid flow.

[0060] In pumps with twisted rotors, the fluid carrying chambers are emptied over a larger revolution of the rotor, which delivers a smoother flow profile. It is possible to overlap the individual flow profiles from each fluid carrying chamber so that the combined flow output is continuous with less fluctuation in flow rate.

[0061] In embodiments of all aspects of the invention involving multiple diaphragms, the diaphragms are preferably spaced equidistantly around the circumference of the cavity in which the rotor sits. In embodiments of all aspects of the invention involving multiple recesses on the rotor, the recesses are preferably spaced equidistantly around the circumference of the rotor.

[0062] In preferred embodiments of all aspects of the invention, the pump comprises three diaphragms positioned equidistantly around the circumference of a cavity in which the rotor is located, and the rotor has two surface recesses which together with the inner surface of the housing form two fluid carrying chambers which carry fluid from a first fluid port to a second fluid port in response to rotation of the rotor.

[0063] If the rotor is twisted, the pump may comprise an equal number of elastically deformable diaphragms and surface recesses on the rotor. In a preferred embodiment of the pump according to the second or third aspect of the invention, the pump comprises two surface recesses on the rotor and two elastically deformable diaphragms.

[0064] In all aspects of the invention, all internal surfaces of the pump can be sterilized using a gas such as ethylene oxide or vaporized hydrogen peroxide.

[0065] According to all aspects of the invention, the first and second fluid ports may be in various locations relative to one another, provided that the first fluid port is in fluid flow communication with a first end of the rotor and the second fluid port is in fluid flow communication with a second end of the rotor. For example, the first and second fluid ports may both be axially aligned with the longitudinal rotational axis of the rotor, or the first and second fluid ports may both be radially aligned with the longitudinal rotational axis of the rotor, or one of the first and second fluid ports may be axially aligned with the longitudinal rotational axis of the rotor and the other of the first and second fluid ports may be radially aligned with the longitudinal rotational axis of the rotor.

[0066] In one embodiment of all aspects of the invention, the first fluid port and the second fluid port are at opposite ends of the rotor. In an alternative embodiment of all aspects of the invention, the first fluid port and the second fluid port may be located within an area of ​​the same end of the rotor, provided that fluid flows from the second chamber through the diaphragm chamber to the second fluid outlet. In an alternative embodiment of all aspects of the invention, the first fluid port and the second fluid port are located within an area of ​​opposite ends of the rotor.

[0067] When the first fluid port and the second fluid port are both radially aligned with respect to the longitudinal rotational axis of the rotor, the first fluid port and the second fluid port may be located on the same side of the rotor, or alternatively, the first fluid port and the second fluid port may be circumferentially spaced around the circumference of the rotor.

[0068] In preferred embodiments of all aspects of the invention, the direction of rotation of the rotor is reversible. In a first direction, the first fluid port is a fluid inlet port and the second fluid port is a fluid outlet port. In the opposite direction, the first fluid port is a fluid outlet port and the second fluid port is a fluid inlet port.

[0069] When a pump according to all aspects of the invention is in operation, fluid flows into the pump via the first fluid port and through an opening at a first end of the rotor into the first rotor cavity. From the first rotor cavity, fluid passes through a first opening between the first rotor cavity and the surface recess into the fluid carrying chamber. The resiliently deformable diaphragm is forced onto the surface of the rotor by a pressurizing means to displace fluid from the fluid carrying chamber through a second opening between the surface recess and the second rotor cavity into the second rotor cavity.

[0070] From the second rotor cavity, the fluid flows to a second fluid port. [Brief description of the drawings]

[0071] Following is a more detailed description of embodiments of the invention, given by way of example only, with reference to the accompanying drawings.

[0072] [Figure 1] FIG. 1 is a schematic partial cutaway of a rotor according to an embodiment of the first or third aspects of the present invention. [Diagram 2] FIG. 2 is a rotor according to an embodiment of the first or third aspects of the present invention showing fluid flow. [Diagram 3] FIG. 3 is a schematic cross-sectional view through a portion of a pump comprising the rotor of FIGS. [Figure 4] FIG. 4 is a schematic, partially cut-away view of a pump according to a second embodiment of the first or third aspect of the present invention. [Diagram 5] FIG. 5 is a cross-sectional view of the pump of FIG. [Figure 6] FIG. 6 is a schematic diagram of a rotor according to an embodiment of the second aspect of the present invention. [Figure 7] FIG. 7 is a schematic illustration of a rotor according to a second embodiment of the second aspect of the present invention. [Figure 8] FIG. 8 is a schematic illustration of a rotor according to a third embodiment of the second aspect of the present invention. [Figure 9]FIG. 9 is a schematic, partially cut-away illustration of a portion of a pump according to an embodiment of the third aspect of the present invention. [Figure 10] FIG. 10 is a schematic, partially cut-away illustration of a portion of a pump according to an alternative embodiment of the third aspect of the present invention. [Figure 11] FIG. 11 is a schematic cross-sectional view of a pump according to an embodiment of the first aspect of the present invention. [Figure 12] FIG. 12 is a schematic diagram of a rotor according to an alternative embodiment of the first or third aspects of the present invention. [Figure 13] FIG. 13 is a schematic, partial cutaway view of the rotor of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0073] It can be seen from Figure 1 that the rotor 10 has a generally cylindrical shape. The rotor 10 has two surface recesses 20 that extend along the longitudinal extent of the rotor 10, generally parallel to the longitudinal axis of rotation 15 of the rotor. The surface recesses 20 are provided by a concave section of the rotor. The rotor comprises a housing-engaging surface area 25 between adjacent surface recesses 20 at each end of the rotor.

[0074] The rotor is hollow and includes a first rotor cavity 30 and a second rotor cavity 35 arranged consecutively within the rotor 10. The rotor includes a drive shaft 40 that extends within the hollow interior of the rotor 10 and is attached thereto.

[0075] Each end 45, 50 of the rotor 10 is open to provide fluid access into the first and second fluid cavities 30, 35, respectively.

[0076] In the embodiment shown in FIG. 1, the rotor 10 further comprises a first groove 52 and a second groove 53 extending along opposing longitudinal edges of the surface recess 20 .

[0077] The slots 55, 60 provide openings between the first rotor cavity 30 and the surface recess 20 and between the second rotor cavity 35 and the surface recess 20, respectively. Each slot 55, 60 is essentially linear, extends along the longitudinal edge of the recess 20 and is essentially parallel to the longitudinal axis of rotation 15 of the rotor. However, the slot 55 providing the first opening is located in the first groove 52 and the slot 60 providing the second opening is located in the second groove 53, the slots 55 and 60 being adjacent to opposite sides of the land 25 extending between the recesses 20, although parallel. For every two surface recesses 20 in the embodiment shown in FIG. 1, there is a slot 55 providing a first opening between the first rotor cavity 30 and the surface recess 20 and a slot 60 providing a second opening between the second rotor cavity 35 and the surface recess 20. The slots 55 and 60 are on opposite sides and opposite ends of the recess 20. The view shown in FIG. 1 shows only one slot 55, 60 in each recess 20.

[0078] 1, both of the slots 55 providing openings between the first rotor cavity 30 and the surface recesses 20 would allow fluid to flow from the first rotor cavity 35 into the chambers formed by each surface recess 20. Similarly, both of the slots 60 would allow fluid to flow from the chambers formed by each surface recess 20 into the second rotor cavity 35.

[0079] FIG. 2 illustrates an alternative embodiment of the rotor of FIG. 1 without the grooves 52, 53 for locating the slots 55 and 60, but similar features are referenced by similar reference numerals. FIG. 2 also illustrates the direction of fluid flow into the first rotor cavity 30 through the openings in the end 45 of the rotor 10, and out of the first rotor cavity through the slots 55 into the chambers (not shown) formed by the surface recesses 20, for a given direction of rotation of the rotor. FIG. 2 also shows fluid flowing from adjacent chambers (not shown) formed by adjacent surface recesses 20 into the slots 60, into the second rotor cavity 35, and out through the open end 50 of the rotor 10. This fluid flow would apply equally to the embodiments of FIG. 1 and FIG. 2.

[0080] FIG. 3 shows a rotor 105 similar to the rotor 10 of FIGS. 1 and 2 within a housing 100. The cross-sectional view of FIG. 3 more clearly shows the arrangement of the first rotor cavity 30 and the second rotor cavity 35. It also shows the bulkhead 70 that separates the first and second rotor cavities 30, 35. FIG. 3 also more clearly illustrates how the drive shaft 40, which is attached to or integral with the rotor, extends from the interior of the hollow rotor 10. Only one slot 60 is shown in this view, which is the opening between the second rotor cavity 35 and a surface recess (not shown). This view illustrates the housing-engaging surface area 25 between adjacent surface recesses (not shown) at each end of the rotor.

[0081] 3 further illustrates a pair of two diaphragm chambers 150, each surrounding the rear face of the diaphragm 120. The diaphragms are urged into contact with the rotor 10 by pressure means (not shown).

[0082] 4 and 5 show a pump 200 having a housing 205, a first fluid port 210 providing a fluid inlet, and a second fluid port 215 providing a fluid outlet. The housing has an inner surface 220 that defines a cavity in which a rotor 225 is located. The rotor 225 has a longitudinal axis of rotation, indicated by dashed line 230. The rotor 225 has a surface 235 at each end thereof and lands that extend between recesses on the surface, which together provide the housing-engaging surface area of ​​the rotor. The rotor shown in FIGS. 4 and 5 is twisted about the longitudinal axis of rotation 230 such that the first end 240 and the second end 245 are offset relative to one another. The rotor 225 has two surface recesses 250 provided by concave areas of the rotor surface. An elastically deformable diaphragm 255 is formed by a thinner section of the housing that provides the cavity in which the rotor 225 is located. The elastically deformable diaphragm 255 has a rotor engagement surface 257 and a rear face 260. A pressure means in the form of a spring 265 contacts the rear face 260 of the diaphragm 255. It can be seen from Figures 4 and 5 that the rotor 225 comprises an elongated body that is generally hollow and comprises a first rotor cavity 270 and a second rotor cavity (not shown). The first rotor cavity 270 has an opening at the first end 240 of the rotor and the second rotor cavity (not shown) has an opening (not shown) at the second end 245 of the rotor. The first rotor cavity 270 and the second rotor cavity (not shown) are separated from each other by a partition wall 280 that extends across the entire interior of the hollow rotor and prevents fluid from flowing along the entire internal length of the rotor. A drive shaft 285 extends from the partition wall 280. The rotor includes a first opening 290 that extends between the first rotor cavity 270 and the rotor surface recess 250. It can be seen from Figure 4 that the first opening 290 has a tapered shape and extends along a longitudinal edge of the section of the surface recess 250 that overlies the first rotor cavity 270 and continues across the land 235 at the rotor first end 240 to create an opening in the housing engagement surface provided by the land 235 at the rotor first end 240.The rotor also comprises a similarly arranged second opening (not shown) extending between the second rotor cavity (not shown) and the surface recess 250. The second opening will be located on the opposite longitudinal edge of the recess 250 and at the opposite end of the rotor 225 so that it overlies the second rotor cavity (not shown). It can be seen in particular from Figure 4 that the pressure means 265 urges the elastically deformable diaphragm 255 into contact with the surface recess 250, and that since the second opening (not shown) is located on the opposite longitudinal edge of the recess 250, the contact line between the diaphragm 255 and the surface recess 250 is located so as to bisect the first opening 290 and the second opening (not shown).

[0083] There are three resiliently deformable diaphragms 255 (not all shown), spaced equidistantly about the circumference of the rotor, and a spring 265 acting against the rear face of each diaphragm provides the pressure means.

[0084] Each of the two surface recesses 250 has a first opening 290 and a second opening extending along opposite longitudinal edges of each recess 250 at opposite ends of the rotor.

[0085] In use of the pump 200, the rotor 225 is rotated by the action of a motor connected to the drive shaft 285, and fluid flows into the first fluid port 210 and then through the open first end 245 of the rotor 225 into the first rotor cavity 270. Fluid flows from the first rotor cavity 270 through each first opening 290 into a fluid carrying cavity provided between the surface recess 250 and the inner surface 220 of the housing. The resiliently deformable diaphragm 255 is urged into contact with the surface of the rotor as it rotates by the action of the spring 265. The action of the diaphragm 255 against the surface of the rotor 225 displaces fluid from the fluid carrying cavity as the rotor rotates, and the fluid flows through the second opening into the second rotor cavity (not shown). From there, the fluid flows out of the pump through the second fluid port 215.

[0086] 6 shows an alternative rotor 300. The rotor is twisted about its longitudinal axis of rotation 315 such that opposing ends 310, 320 of the rotor are offset with respect to one another.

[0087] It can be seen that a result of twisting the rotor is to distort the shape of the surface recesses 330, 335. Because the first slot 340 providing the opening between the first rotor cavity 350 and the surface recess 330 and the second slot 345 providing the opening between the second rotor cavity 355 and the surface recess 335 extend along opposite edges of the recesses 330, 335, twisting the rotor also causes the slots 340, 345 to become angled relative to the longitudinal axis of rotation 315 of the rotor 300. Figure 4 also illustrates that twisting the rotor also angles the land 360 between adjacent recesses 330, 335, which becomes angled relative to the longitudinal axis of rotation 315 of the rotor 300.

[0088] Figure 7 shows rotor 400, which is a variation of rotor 300 of Figure 5. In this embodiment, a first slot 440 provides an opening between first rotor cavity 450 and surface recess 430 and continues through first end 410 of the rotor. A second slot 445, providing an opening between second rotor cavity 455 and surface recess 435, continues through second end 420 of the rotor. It can be seen that first slot 440 and second slot 445 extend through housing engaging surface area 460 at each end of the rotor.

[0089] Dashed line 465 illustrates the location of a bulkhead that extends across the interior of rotor 400 and separates first rotor cavity 450 and second rotor cavity 455 .

[0090] This arrangement of first and second slots is not limited to twisted rotors as illustrated in Figures 4 and 7. In the rotors of Figures 1 and 2, the slots 55, 60 may also extend through the first and second ends 45, 50, respectively, and through the surface-engaging surface area 25.

[0091] Figure 8 shows rotor 500, which is a variation of rotor 400 of Figure 6. In this embodiment, a first slot 540 provides an opening between a first rotor cavity 550 and a surface recess 530. The slot is open at a first end 510 of the rotor. A second slot 545 provides an opening between a second rotor cavity 555 and a surface recess 535.

[0092] The slots are open at the rotor second end 520. It can be seen that the first slot 540 and the second slot 545 extend through the housing engagement surface area 560 at each end of the rotor. In the embodiment of Figure 8, the first slot 540 and the second slot 545 are tapered with their widest portions forming openings in the rotor first end 510 and second end 520, respectively.

[0093] Dashed line 565 illustrates the location of a bulkhead that extends across the interior of rotor 500 and separates first rotor cavity 550 and second rotor cavity 555 .

[0094] This arrangement of first and second slots is not limited to twisted rotors. In the rotor of Figures 1 and 2, the slots 55, 60 may also be tapered and extend through the first and second ends 45, 50, respectively, and through the surface-engaging surface area 25.

[0095] 9 shows a portion of a pump 600 having a housing 605, a first fluid port 610 providing a fluid inlet, and a second fluid port (not shown) providing a fluid outlet. The housing has an inner surface 620 that defines a cavity in which a rotor 625 sits. The rotor 625 has a longitudinal axis of rotation, indicated by dashed line 630. The rotor 625 has lands 635 between recesses on its surface at each end thereof, which together provide the housing-engaging surface area of ​​the rotor. The rotor 625 has two surface recesses 650 provided by the concave areas of the rotor surface. A resiliently deformable diaphragm 655 is formed by a thinner section of the housing that provides the cavity in which the rotor 625 sits. The resiliently deformable diaphragm 655 has a rotor-engaging surface 657 and a rear surface 660. The elastically deformable diaphragm 655 has linear ribs 665 projecting from a rear surface 660 of the diaphragm 655. The linear ribs 665 are angled relative to the longitudinal axis of rotation 630 of the rotor. It can be seen from FIG. 9 that the rotor 625 is generally hollow and comprises an elongated body comprising a first rotor cavity 670 and a second rotor cavity (not shown) at opposite ends of the rotor 625. The first rotor cavity 670 has an opening at a first end 675 of the rotor and the second rotor cavity (not shown) has an opening (not shown) at a second end (not shown) of the rotor. The first rotor cavity 670 and the second rotor cavity (not shown) are separated from each other by a bulkhead (not shown) that extends across the entire interior of the hollow rotor to prevent fluid from flowing along the entire interior length of the rotor. The rotor 625 includes a first opening 690 that extends between the first rotor cavity 670 and the rotor's surface recess 650. The first opening 690 has a linear shape and extends along a longitudinal edge of a section of the surface recess 650 that overlies the first rotor cavity 670. The rotor also includes a similarly arranged second opening (not shown) that extends between a second rotor cavity (not shown) and the surface recess 650. The second opening is located on an opposite longitudinal edge of the recess 650 and at an opposite end of the rotor 625 such that it overlies the second rotor cavity (not shown).Each surface recess 650 has a first opening 690 and a second opening arranged at opposite ends of the rotor and on opposite sides of the recess.

[0096] In use of the pump 600, the rotor 625 is rotated by the action of a motor connected to the drive shaft 685, and fluid flows into the first fluid port 610 and then into the first rotor cavity 670 through the open first end 675 of the rotor 625. Fluid flows from the first rotor cavity 670 through each first opening 690 into a fluid carrying cavity provided between the surface recess 650 and the inner surface 620 of the housing. The elastically deformable diaphragm 655 is urged into contact with the surface of the rotor as it rotates by the action of a pressurizing means (not shown). The action of the diaphragm 655 against the surface of the rotor 625 displaces fluid from the fluid carrying cavity as the rotor rotates, and the fluid flows through the second opening (not shown) into the second rotor cavity (not shown). From there the fluid flows out of the pump through the second fluid port (not shown).

[0097] 10 shows a portion of a pump 700 having a housing 705, a first fluid port 710 providing a fluid inlet, and a second fluid port (not shown) providing a fluid outlet. The housing has an inner surface 720 that defines a cavity in which a rotor 725 sits. The rotor 725 has a longitudinal axis of rotation, indicated by dashed line 730. The rotor 725 has lands 735 between recesses on its surface at each end thereof, which together provide the housing-engaging surface area of ​​the rotor. The rotor 725 has two surface recesses 750 provided by the concave areas of the rotor surface. A resiliently deformable diaphragm 755 is formed by a thinner section of the housing that provides the cavity in which the rotor 725 sits. The resiliently deformable diaphragm 755 has a rotor-engaging surface 757 and a rear surface 760. The elastically deformable diaphragm 755 has linear ribs 765 projecting from a rear surface 760 of the diaphragm 755. The linear ribs 765 are angled relative to the longitudinal axis of rotation 730 of the rotor. It can be seen from FIG. 10 that the rotor 725 is generally hollow and comprises an elongated body comprising a first rotor cavity 770 at opposite ends of the rotor 725 and a second rotor cavity (not shown). The rotor 725 is twisted about the longitudinal axis of rotation 730 such that the opposite ends of the rotor 725 are offset relative to one another. The rotor 725 is twisted in a direction opposite to the direction in which the ribs 765 are angled relative to the longitudinal axis of rotation 730 of the rotor. The first rotor cavity 770 has an opening at a first end 775 of the rotor and the second rotor cavity (not shown) has an opening (not shown) at a second end (not shown) of the rotor. The first rotor cavity 770 and the second rotor cavity (not shown) are separated from each other by a partition (not shown) that extends across the entire interior of the hollow rotor to prevent fluid from flowing along the entire interior length of the rotor. The rotor 725 includes a first opening 790 that extends between the first rotor cavity 770 and the rotor surface recess 750.The first opening 790 has a tapered shape and extends along a longitudinal edge of the section of the surface recess 750 that overlies the first rotor cavity 770 and continues across the land 735 at the first end 775 of the rotor to create an opening in the housing engagement surface provided by the land 735 at the first end 775 of the rotor. The rotor also includes a similarly arranged second opening (not shown) that extends between the second rotor cavity (not shown) and the surface recess 750. The second opening is located on the opposite longitudinal edge of the recess 750 and at the opposite end of the rotor 725 such that it overlies the second rotor cavity (not shown). Each surface recess 750 has a first opening and a second opening arranged at opposite ends of the rotor and on opposite sides of the recess.

[0098] In use of the pump 700, the rotor 725 is rotated by the action of a motor connected to the drive shaft 785, and fluid flows into the first fluid port 710 and then through the open first end 775 of the rotor 725 into the first rotor cavity 770. Fluid flows from the first rotor cavity 770 through each first opening 790 into a fluid carrying cavity provided between the surface recess 750 and the inner surface 720 of the housing. The elastically deformable diaphragm 755 is urged into contact with the surface of the rotor as it rotates by the action of a pressurizing means (not shown). The action of the diaphragm 755 against the surface of the rotor 725 displaces fluid from the fluid carrying cavity as the rotor rotates, and the fluid flows through the second opening into the second rotor cavity (not shown). From there the fluid flows out of the pump through the second fluid port (not shown).

[0099] FIG. 11 illustrates a cross-sectional view through a portion of a pump according to an embodiment of the present invention. This view illustrates the action of multiple diaphragms against a surface of a rotor that includes multiple recesses. In particular, FIG. 11 shows a housing 910 with three elastically deformable diaphragms 920 that are formed integrally with the housing, each of which is provided by a thinner section of the housing. The section of the housing that provides the diaphragms is thin enough to allow the diaphragms to be elastically deformable. The three diaphragms 920 are equidistantly spaced about the circumference of the rotor 930.

[0100] The rotor 930 includes two surface recesses 940 that form, with the inner surface 945 of the housing, two fluid-carrying chambers 950 .

[0101] Each diaphragm 920 is urged into contact with the surface of the rotor 930 by spring means 955 located in a diaphragm chamber 960. The spring means 955 ensures that each resiliently deformable diaphragm 920 remains in contact with the surface of the rotor 930 as it rotates and the surface profile of the rotor 930 varies. As can be seen in Figure 11, each spring means 955 comprises a rib which acts against the rear face of the diaphragm 920.

[0102] 12 and 13 illustrate an example of a rotor 1000 comprising an elongated body, the body being generally hollow and comprising a first rotor cavity 1010 and a second rotor cavity 1015. The first and second rotor cavities extend longitudinally along the length of the rotor and at least partially extend alongside one another. The first and second rotor cavities 1010 and 1015 are separated from one another by a partition wall 1020. The partition walls are staggered and separate the first and second rotor cavities 1010, 1015 such that the first and second rotor cavities 1010 and 1015 are not in direct fluid communication. The rotor further comprises two recesses 1025 and 1030. Each recess includes a first opening 1035 between the first rotor cavity 1010 and the recesses 1025, 1030, and a second opening 1040 between the recesses 1025, 1030 and the second rotor cavity 1015. In Figures 13 and 14, only the second opening 1040 of the recess 1030 is illustrated and only the first opening 1035 of the recess 1025 is illustrated. The first opening 1035 and the second opening 1040 in the rotor 1000 extend along a major portion of the opposing longitudinal edges of each recess 1025, 1030. However, the arrangement of the first and second openings 1035, 1040 and the bulkhead 1020 is such that the first opening 1035 is open only into the first rotor cavity 1010 and the second opening 1040 is open only into the second rotor cavity 1015. It can further be seen from Figures 12 and 13 that the first rotor cavity is open only at the first end 1045 of the rotor and the second rotor cavity 1015 is open only at the second end 1050 of the rotor.

[0103] The arrows indicate the direction of fluid flow in one direction of rotation when the rotor 1000 is used in a pump according to any aspect of the invention. It can be seen from FIG. 13 that fluid flows into the first rotor cavity 1010 through the first end 1045, from where it flows into the recesses 1025, 1030 through the first opening 1035. As the pump operates and the rotor rotates in a given direction, the fluid in the recesses 1025, 1030 is displaced by pressurizing means (not shown) through the second opening 1040 into the second rotor cavity 1015 and out through the open second end 1050 of the rotor 1000. If the direction of rotation of the rotor is reversed, the direction of fluid flow will also be reversed.

Claims

1. A pump comprising: a first fluid port and a second fluid port; a housing having an inner surface defining a cavity, the rotor being positioned within the cavity; a rotor rotatably mounted within the housing, the rotor having a longitudinal axis of rotation, the rotor comprising a housing engaging surface area that forms a sealing interference fit with the inner surface of the housing, and a surface recess that forms with the inner surface of the housing a fluid carrying chamber that carries fluid from the first fluid port to the second fluid port in response to rotation of the rotor; a plurality of resiliently deformable diaphragms each providing a portion of the inner surface of the housing, each diaphragm having a rotor engaging surface and a rear surface opposite the rotor engaging surface, the rotor engaging surface of each diaphragm being urged into contact with the rotor by pressure means acting against the rear surface of the diaphragm, the number of said resiliently deformable diaphragms exceeding the number of said surface recesses on the rotor; Equipped with the rotor comprises an elongated body and a drive shaft, the body being generally hollow and comprising separate first and second rotor cavities, the first rotor cavity having an opening at a first end of the rotor and the second rotor cavity having an opening at a second end of the rotor, the rotor further comprising a first opening between the first rotor cavity and the surface recess and a second opening between the surface recess and the second rotor cavity; the pump is arranged such that when the rotor is positioned within the cavity in the housing, the first fluid port is in fluid flow communication with the first rotor cavity through the opening at the first end of the rotor and the second fluid port is in fluid flow communication with the second rotor cavity through the opening at the second end of the rotor; The pump is arranged such that as the rotor rotates, at least one of the elastically deformable diaphragms always bisects the first opening and the second opening on the rotor surface recess.

2. The pump of claim 1 comprising a plurality of surface recesses forming a corresponding number of fluid carrying chambers with the inner surface of the housing.

3. 2. The pump of claim 1, wherein the rotor is twisted about its longitudinal axis of rotation such that the first and second ends of the rotor are rotationally offset relative to one another by at least 10 degrees, or by at least 15 degrees, or by no more than 20 degrees.

4. 2. The pump of claim 1, wherein the housing comprises three elastically deformable diaphragms and the rotor comprises two surface recesses that form two fluid carrying chambers with the inner surface of the housing.

5. 2. The pump of claim 1, comprising a plurality of surface recesses, each surface recess comprising a first opening between the first rotor cavity and the surface recess and a second opening between the surface recess and the second rotor cavity.

6. 2. The pump of claim 1, wherein each of said plurality of resiliently deformable diaphragms is urged into contact with said rotor by a separate compressive means acting against said rear face of said diaphragm.

7. 2. The pump of claim 1, wherein each of said plurality of resiliently deformable diaphragms is urged into contact with said rotor by a common pressurizing means acting against said rear faces of all of said diaphragms.

8. 2. The pump of claim 1, wherein the pressurizing means comprises a spring, a resilient member, and / or a fluid acting against the rear face of the diaphragm.

9. 9. The pump of claim 8, wherein the fluid acting against the rear surface of the diaphragm is a pumped fluid.

10. 2. The pump of claim 1, wherein the or each resiliently deformable diaphragm includes a linear rib extending longitudinally along the length of the rear face of the diaphragm.

11. 2. The pump of claim 1, wherein a linear rib acts against the rear face of the or each resiliently deformable diaphragm extending longitudinally along the length of said diaphragm.

12. 11. The pump of claim 10, wherein the linear ribs are angled relative to the longitudinal axis of rotation of the rotor by at least 10 degrees, or by at least 15 degrees, or by at least 20 degrees.

13. 2. The pump of claim 1, comprising a rotor twisted about its longitudinal axis of rotation such that first and second ends of the rotor are rotationally offset relative to one another by at least 10 degrees, the rotor twisted in an opposite direction to linear ribs on the elastically deformable diaphragm.

14. 2. The pump of claim 1, wherein the rotor comprises a generally cylindrical body, one or more surface recesses formed in the generally cylindrical body, and the housing engaging surface area that forms a sealing interference fit with the inner surface of the housing comprises an entire cylindrical surface of the rotor, excluding the one or more surface recesses on the rotor.

15. 15. The pump of claim 14, wherein the housing engaging surface area of ​​the rotor comprises a cylindrical area at each end of the rotor, no surface recesses are formed within the cylindrical areas, the cylindrical areas being connected by an elongated section of the rotor surface separating the longitudinal extents of adjacent recesses.

16. 5. The pump of claim 4, wherein the first and second rotor chambers are separated from one another by a partition extending into the hollow interior of the rotor.

17. 2. The pump of claim 1, wherein the first opening between the first rotor cavity and the surface recess and the second opening between the surface recess and the second rotor cavity are each provided by a slot in the rotor.

18. 2. The pump of claim 1, wherein the first opening between the first rotor cavity and the surface recess is located adjacent, and preferably continuous with, an edge of the recess that will form a leading edge of the recess as the rotor rotates, and the second opening between the surface recess and the second rotor chamber is located adjacent, and preferably continuous with, an opposite edge of the recess that will form a trailing edge of the recess as the rotor rotates in the direction.

19. 2. The pump of claim 1, wherein the first opening between the first rotor cavity and the surface recess extends along substantially an entire axial length of the surface recess overlying the first rotor cavity, and the second opening between the surface recess and the second rotor cavity extends along substantially an entire axial length of the surface recess overlying the second rotor cavity.

20. 20. The pump of claim 19, wherein the first opening between the first rotor cavity and the surface recess extends along an entire axial length of the surface recess overlying the first rotor cavity and continues through at least one of the first ends of the rotor, and / or the second opening between the surface recess and the second rotor cavity extends along an entire axial length of the surface recess overlying the second rotor cavity and through the second end of the rotor.

21. 21. The pump of claim 20, wherein the first opening and / or the second opening are tapered and open outwardly to a widest portion as the opening passes through the end of the rotor.

22. 2. The pump of claim 1, wherein the rotor comprises a first groove and a second groove in a surface of the rotor extending along substantially the entire length of opposing longitudinal edges of the surface recess, the first opening between the first rotor cavity and the surface recess extending along a portion of the first groove that overlies the first rotor cavity, and the second opening between the surface recess and the second rotor cavity extending along a portion of the second groove that overlies the second rotor cavity.

23. A pump comprising: a first fluid port and a second fluid port; a housing having an inner surface defining a cavity, the rotor being positioned within the cavity; a rotor rotatably mounted within the housing, the rotor having a longitudinal axis of rotation, the rotor comprising a housing engaging surface area that forms a sealing interference fit with the inner surface of the housing and a surface recess that forms with the inner surface of the housing a fluid carrying chamber that carries fluid from the first fluid port to the second fluid port in response to rotation of the rotor, the rotor twisted about its longitudinal axis of rotation such that first and second ends of the rotor are rotationally offset relative to one another by at least 10 degrees; a resiliently deformable diaphragm providing a portion of the inner surface of the housing, the diaphragm having a rotor engaging surface and a rear surface opposite the rotor engaging surface, the rotor engaging surface of the diaphragm being urged into contact with the rotor by pressure means acting against the rear surface of the diaphragm; Equipped with the rotor comprises an elongated body and a drive shaft, the body being generally hollow and comprising separate first and second rotor cavities, the first rotor cavity having an opening at a first end of the rotor and the second rotor cavity having an opening at a second end of the rotor, the rotor further comprising a first opening between the first rotor cavity and the surface recess and a second opening between the surface recess and the second rotor cavity; the pump is arranged such that when the rotor is positioned within the cavity in the housing, the first fluid port is in fluid flow communication with the first rotor cavity through the opening at the first end of the rotor and the second fluid port is in fluid flow communication with the second rotor cavity through the opening at the second end of the rotor; The pump is arranged such that as the rotor rotates, the resiliently deformable diaphragm always bisects the first opening and the second opening on the rotor surface recess.

24. A pump comprising: a first fluid port and a second fluid port; a housing having an inner surface defining a cavity, the rotor being positioned within the cavity; a rotor rotatably mounted within the housing, the rotor having a longitudinal axis of rotation, the rotor comprising a housing engaging surface area that forms a sealing interference fit with the inner surface of the housing, and a surface recess that forms with the inner surface of the housing a fluid carrying chamber that carries fluid from the first fluid port to the second fluid port in response to rotation of the rotor; a resiliently deformable diaphragm providing a portion of the inner surface of the housing, the diaphragm having a rotor engaging surface and a rear surface opposite the rotor engaging surface, the rotor engaging surface of the diaphragm being urged into contact with the rotor by pressure means acting against the rear surface of the diaphragm, a linear rib either upstanding from or acting against the rear surface of the resiliently deformable diaphragm, the linear rib being angled relative to the longitudinal axis of rotation of the rotor by at least 10 degrees; Equipped with the rotor comprises an elongated body and a drive shaft, the body being generally hollow and comprising separate first and second rotor cavities, the first rotor cavity having an opening at a first end of the rotor and the second rotor cavity having an opening at a second end of the rotor, the rotor further comprising a first opening between the first rotor cavity and the surface recess and a second opening between the surface recess and the second rotor cavity; the pump is arranged such that when the rotor is positioned within the cavity in the housing, the first fluid port is in fluid flow communication with the first rotor cavity through the opening at the first end of the rotor and the second fluid port is in fluid flow communication with the second rotor cavity through the opening at the second end of the rotor; The pump is arranged such that as the rotor rotates, the resiliently deformable diaphragm always bisects the first opening and the second opening on the rotor surface recess.

25. 25. The pump of claim 24, wherein the rotor is twisted about its longitudinal axis of rotation such that first and second ends of the rotor are rotationally offset relative to one another by at least 10 degrees, the rotor being twisted in a direction opposite to the angulation of the ribs.

26. 25. The pump of claim 24 comprising a plurality of resiliently deformable diaphragms.

27. 25. The pump of claim 24, comprising a rotor having a plurality of surface recesses that form a corresponding number of fluid carrying chambers with the inner surface of the housing.

28. 25. The pump of claim 24 comprising an equal number of elastically deformable diaphragms and surface recesses on said rotor.

Images