Abstract: A multi-drive pump may include a pump housing, an inlet port, an outlet port, a primary pump gear, a secondary pump gear, a first internal mechanical drive mechanism coupled to the primary pump gear and a second internal mechanical drive mechanism and an internal electro-magnetic drive mechanism coupled to the secondary pump gear. The pump housing may define an internal volume fluidly coupled to the inlet port and the outlet port. The primary pump gear and the secondary pump gear may be positioned in the pump housing and coupled to one another. Rotation of the primary pump gear and the secondary pump gear draws fluid into the inlet port and expels fluid from the outlet port. The primary pump gear may be rotated by the first internal mechanical drive mechanism and the secondary pump gear may be rotated by the second internal mechanical drive mechanism and the internal electro-magnetic drive mechanism.

Abstract: A rotary compressor includes a compression mechanism, an electric motor and a controller. The compression mechanism includes a piston and a cylinder having two cylinder chambers. The electric motor is configured to change volumes of the cylinder chambers by eccentrically moving the cylinder and the piston relative to each other. The controller is configured to change an output torque of the electric motor in accordance with a variation in a load torque of the compression mechanism in one turn of rotation.

Abstract: An object of the present invention is to provide a uniaxial eccentric screw pump capable of transferring and filling a fluid while realizing high flow rate accuracy, low pulsation, and long life. A uniaxial eccentric screw pump (11) in which an external screw type rotor (12) is fittingly inserted in an inner hole (13a) of an internal screw type stator (13), the rotor (12) and the stator (13) are separately, rotatably supported, and a rotation central axis of the rotor (12) and a rotation central axis of the stator (13) are spaced apart from each other is configured such that the rotor (12) and the stator (13) are separately rotated by a rotor driving portion (27) and a stator driving portion (19), respectively, and the rotor (12) and the stator (13) are rotated with the rotor (12) and the stator (13) not contacting each other.

Abstract: A pump case of an electric pump is constructed by coupling a first pressed member formed with a cylindrical part for holding a first rolling ball bearing rotatably supporting a rotary shaft, and a second pressed member formed with a recess for receiving an inner rotor provided at a tip end of the rotary shaft to each other. Because the first pressed member and the second pressed member are formed by deep-drawing work, it is possible to achieve simplification of the structure and reduction of the cost, as compared with the pump case which has been produced from an aluminum die casting or the like, as in the related art.

Abstract: An electric pump unit which comprises an outer rotor having a trochoidal tooth profile and an inner rotor which meshes with the outer rotor in such a state the inner rotor and the outer rotor are placed eccentric relative to each other for rotation and also comprises a pump part which is accommodated in a bottomed cylindrical pump housing. A low pressure portion and a high pressure portion are formed by both the rotors, and oil is made to be sucked and discharged through an inlet port and an outlet port which communicate respectively with the low pressure portion and the high pressure portion. A relief valve is provided for circulating oil from the high pressure portion to the low pressure portion when an oil pressure at the high pressure side reaches or exceeds a predetermined pressure.

Abstract: The invention relates to an internal gear pump including: a rotor member including an outer rotor provided with inner teeth to which a torque supplied from a driving device is transmittable; an inner rotor provided with outer teeth engageable with the inner teeth of the outer rotor so to be driven by a rotation of the outer rotor, wherein a rotation axis of the inner rotor is eccentric with respect to a center of the rotor member; a pair of housings provided on opposite sides of the rotor member and the inner rotor to support the rotor member and the inner rotor; and at least one rolling bearing provided between at least one of the housings and the rotor member.

Abstract: An apparatus for removing a stator tube from a position about a rotor of a progressing cavity pump is provided. The apparatus includes an actuator assembly having a base and a piston which is longitudinally displaceable relative to the base, and a pusher rod. The base of the actuator assembly is removably attachable to a discharge end of the stator tube. The pusher rod is longitudinally releasably attachable to the piston at a plurality of locations along the length of the pusher rod and is located to engage the rotor when the base is coupled to the stator tube. The pusher rod is coupled to the piston and the piston is driven by the actuator assembly. With only slight modifications the apparatus may also be used to install the stator tube on the rotor when operated in a substantially opposite way.

Abstract: The combined pump is a novel pumping system for fluids (liquids, gases) and for multiple-phase mixtures. This combined pump comprises a helical rotor on which a rotodynamic impeller is mounted. The helical rotor and impeller turns without touching inside a helical stator, and this helical rotor/impeller assembly and stator are arranged so that the cavities formed move from the suction toward the discharge. Using the rotodynamic impeller, the combined pump provides a pressurized fluid layer between the helical rotor/impeller assembly and the stator under conditions capable of improving the performances and the reliability of the pump.

Abstract: A two-shaft vacuum pump has a simplified drive motor. The two-shaft vacuum pump has a synchronous motor as a drive motor which motor rotor is permanently excited. Permanently excited motor rotors are sufficiently small and of light weight such that rotor supporting bearings can be omitted. This also eliminates the problems associated with cooling and lubrication of the supporting bearings.

Abstract: A progressing cavity pump including a drive component configured to be rotated by a motor and a driven component that is magnetically rotationally coupled to the drive component. The driven component is fluidly isolated from the drive component. The pump further includes a wobble stator and a rotor positioned inside the stator and configured such that rotation of the driven component causes relative rotation between the rotor and the stator, which in turn causes material in the pump to be pumped therethrough.

Abstract: A motor-pump unit, in particular for a power steering system of a motor vehicle, comprises a housing, a pump, and a drive motor. The pump is constructed as a prefabricated pump module. Both the pump module and the motor are received directly in the housing.

Abstract: A motor direct drive air pump comprises a housing, a first shaft, and a second shaft. The housing is formed with a left space and a right space; one of the spaces is a compression chamber having an air inlet and an air outlet; the other space has a transmission chamber and a driving chamber; stators are disposed in the driving chamber. A first shaft is disposed through a central partition of the housing; a first impeller is embedded at a portion of the first shaft located in the compression chamber, while a first gear is embedded at a portion of the first shaft located in the transmission chamber, and rotors are embedded at a portion of the first shaft located in the compression chamber.

Abstract: A supercharger can have a lubrication system that includes a speed increasing mechanism, accommodated in a second housing, for increasing the rotation speed of a drive shaft and transmitting the increased rotation speed to a rotary shaft. An oil sump can be configured to for hold lubricant oil for lubricating the speed increasing mechanism. A pump mechanism can be driven by the rotation of the drive shaft to supply the lubricant oil held in the oil sump to the speed increasing mechanism, in which the pump mechanism is constituted with a screw pump made up of a screw provided on the drive shaft. A pump chamber can rotatably support the drive shaft and accommodate the screw. An oil introduction hole and an oil introduction tube can connect the oil sump and the interior of the pump chamber, and a gap can be formed between the screw and the pump chamber.

Abstract: A hydrocarbon well pump has impellers and diffusers configured with inner and outer sections. The central section contains impeller passages configured for pumping liquid. The outer section contains turbine blades for compressing gas. A cylindrical sidewall separates the two sections. A driven shaft rotates the central and outer sections in unison.

Abstract: In an electric pump unit, communication between arcuate ports provided in correspondence with a discharge side and a suction side of an internal gear pump is selectively permitted and prohibited in correspondence with movement of a spool of a relief valve. If fluid pressure at the discharge side of the internal gear pump becomes greater than or equal to a predetermined value, the spool moves across an inner arc of one of the arcuate ports corresponding to the suction side of the internal gear pump and from a position at which the spool prohibits the communication between the arcuate ports to a position at which the spool permits the communication. As the spool moves away from the position at which the spool blocks the communication between the arcuate ports, the opening degree of the relief valve changes in accordance with a downward convex curve.

Abstract: This progressing cavity pump includes a helical rotor (2) mounted to turn inside a helical stator (3). The stator (3) and the rotor (2) are disposed such that the cavities (4) formed therebetween move from the inlet (5) towards the outlet (6). In this cavity pump, hydraulic regulation (HR) means are provided for obtaining internal recirculation of the pumped fluid between at least two of the cavities (4) under conditions capable of performing at least one function selected from: achieving the desired pressure distribution along the pump, stabilizing the temperatures, controlling the leakage flow rates, and compensating for the volumes of compressed gas.

Abstract: The invention relates to a water-injected screw compressor, comprising a compressor element (2) with a housing (7) which borders a compression chamber (8) in which two rotors (9, 10) are installed, which, by means of an axle ends (13, 14; 15, 16), are borne in the housing (7) by means of water-lubricated slide bearings (1), an electric motor (3) comprising a housing (18) which carries a stator (19) at the inside, which stator surrounds a rotor (21) with a rotor shaft (22). An axle end (13) of one of the rotors (9) is directly coupled to or forms one piece with the rotor shaft (22) of the motor (3), said rotor shaft being located in the prolongation of said axle end. The rotor shaft (22) of the motor (3) is borne in at least one water-lubricated slide bearing (23).

Abstract: An oil pump includes a partition for dividing an outlet port into a first passage section on the upstream side and a second passage section on the downstream side, wherein a discharge passage fluidly communicates with the first passage section, and a relief valve is disposed in the second passage section.

Abstract: A single-shaft vacuum positive displacement pump (10) comprises two pump stages (12,14) each provided with a pump rotor (13,15) and a drive motor (16). The drive motor (16) is axially arranged between the two pump stages (12,14), wherein the shaft (22) supports the pump rotors (13,15) and the motor rotor (17).

Abstract: A motor-mounted internal gear pump 80 includes: a pump part 81 which sucks and discharges hydraulic fluid; and a motor part 82 which drives the pump 81. The pump part 81 includes: an inner rotor 1 with teeth on its outer surface; an outer rotor 2 with teeth on its inner surface to mesh with the teeth of the inner rotor; and pump casings 3, 4 which house the inner rotor 1 and the outer rotor 2. The motor part 82 includes a rotator 11 and a stator 12 which rotates the rotator 11. A common member 112 of permanent magnet material as resin containing magnetic powder serves as the rotator 11 and the outer rotor 2. This structure assures further inexpensiveness and reliability while maintaining compactness and inexpensiveness in functions.

Abstract: A motor-integrated internal gear pump that is inexpensive and highly reliable while maintaining characteristics of small size and inexpensive functions. The motor-integrated internal gear pump (80) has a pump section (81) with an inner rotor (1), an outer rotor (2), a pump casing, and an inner shaft (5). The pump casing has flat inner surfaces facing both end surfaces of each of the inner rotor (1) and the outer rotor (2). The inner shaft (5) has a bearing section (51) inserted into a shaft hole of the inner rotor (1) and fitting sections extending axially outward from both end surfaces of the inner shaft (51). The pump casing is constructed from two pump casing members (3, 4) where the flat inner surfaces (25, 26) are formed as separate members.

Abstract: A motor-pump unit is provided that has at least two internal gearwheel pumps axially aligned that are driven off of the rotor of the electric motor. The rotor of the electric motor is U-shaped and is concentrically disposed about the pump. The web of the U-shape is disposed in the region of the rotational axis with internal toothing that meshes with pinions of the at least two internal gearwheel pumps.

Abstract: A screw pump includes a pair of screw rotors (2a, 2b) having teeth which are held in mesh with each other for drawing and discharging a fluid by rotating the screw rotors (2a, 2b) synchronously in opposite directions. The teeth of the screw rotors (2a, 2b) have the same shape as each other and are coiled helically in opposite directions. The teeth of the screw rotors (2a, 2b) have an axial tooth profile which allows a pair of facing teeth surfaces T of the screw rotors (2a, 2b) to be brought into contact with each other only at a pitch line P when the pair of facing teeth surfaces T are brought into contact with each other.

Abstract: An electric pump comprises a case in which a core being enwound by a coil is embedded, a permanent magnet formed in a cylindrical shape, having a central axis being identical to that of the core, and positioned so as to face an inner peripheral side of the core, an outer rotor fixed to an inner peripheral side of the permanent magnet, a rotor unit including the permanent magnet and the outer rotor, an inner rotor having a central axis, which is eccentric from a central axis of the core, so as to rotate; and an inscribed-type pump for carrying out, by means of rotation of the inner rotor, which is engaged with the outer rotor so as to rotate in accordance with rotation of the outer rotor, intake and exhaust of fluids, wherein the rotor unit includes a slide surface extending in an axial direction; the case includes a cylindrical projecting ring portion having an identical central axis to that of the core, and the rotor unit is rotatably supported by the peripheral surface of the cylindrical projecting ring por

Abstract: A pump suitable for use with contamination-sensitive fluids such as food products or pharmaceutical fluids includes an outer casing containing an internal cavity, the outer casing having an enlarged opening on one end, a second opening on an opposite end, a first inlet port and a first outlet port. The internal cavity has pumping parts disposed substantially within the cavity, the pumping parts comprising end blocks each having a drive and idler shaft support, a drive shaft and an idler shaft, a plurality of pumping wheels, and a center block with an internal cavity defining a pumping chamber. The enlarged opening of the outer casing is sealed by an end cap, an elastomeric seal and a quickly removable industry-standard clamp. The second opening of the outer casing is provided for the drive shaft and is sealed by an elastomeric shaft seal. The pumping wheels are rotationally active with, but not axially retained, on respective support shafts and are substantially free to slide on their respective axes.

Abstract: An electric oil pump apparatus includes a pump housing a drive side communicating portion, a motor housing having a pump side communicating portion communicating with the drive side communicating portion, a bearing portion arranged at one of the drive side communicating portion and the pump side communicating portion, and a shaft rotatably supported by the bearing portion. A one end of the shaft extends in the pump housing and is provided with a drive rotor capable of feeding the oil in response to rotation of the shaft. The other end of the shaft extends in the motor housing and is provided with a permanent magnet.

Abstract: An integrated speed reducer and gerotor pump is disclosed. The device comprises a motor, a speed reducer, and a gerotor pump. The motor provides torque at an elevated speed. The speed reducer is coupled with the motor and converts the torque at an elevated speed into torque at a reduced speed. The gerotor pump is coupled with the speed reducer and uses the torque at the reduced speed for pumping fluids.

Abstract: An oil pump unit includes an additional outlet port connected to the downstream side of the pump through the pump cover. With this additional port, the oil pump unit is able to have electronic vacuum and pressure sensors upstream and downstream of the pump for remote monitoring of the pump. The invention is particularly suited for oil pump units which have a main discharge outlet port through the one side of the pump body and a main inlet port through an opposing side of the pump cover. The invention is also particularly suited for oil pump units having a solenoid valve mounted at the top side of the pump body which prevents installation of a pressure sensor along the top side.

Abstract: A gear pump and method for pumping elastomeric material having two gears with meshing herringbone gear teeth. Each of the gear teeth has helical side portions and a curved central portion which extends circumferentially of the gear a distance equal to at least one half the pitch of the gear teeth to provide a continuous squeezing contact between the teeth of the two gears for pumping a uniform strip of elastomeric material from the gear pump.

Abstract: A refrigerant pump includes a thin-walled hermetic vessel and a thick-walled hermetic vessel having an end inserted into and secured to an end of the thin-walled hermetic vessel. A stator of an electric motor unit is fitted outside the thin-walled hermetic vessel, while a rotor of the electric motor unit is accommodated inside the thin-walled hermetic vessel. A pump mechanism is fitted inside the thick-walled hermetic vessel, and a rotational force of the rotor is transmitted to the pump mechanism by the drive shaft.

Abstract: To counter downstream oil infiltration through a shaft seal, a small portion of the compressed fluid is diverted from downstream to upstream through a passageway in a rotor. The diverted fluid is introduced to a space at a downstream side of the seal. An exemplary implementation is in a compressor having a central male rotor intermeshed with a pair of female rotors. The seal is located at an upstream (inlet) end of the lobed working portion of the male rotor.

Abstract: A vacuum pump (1) comprising a pump chamber casing (5) accommodating two co-operating rotors (2, 3) which are respectively arranged on a shaft (8, 9). A bearing/gear chamber (6) is disposed adjacent to the pump chamber casing (5) in which the rotor shafts (8, 9) are cantilevered and provided with a synchronisation gear (17). A drive motor (25) whose drive shaft (28) extending parallel to the rotor shafts (8, 9) and is provided with a drive gear (35). A gear stage (37) is disposed between the drive shaft (28) and one of the rotor shafts (8, 9). In order to provide a machine of this type which can be embodied in a compact form, the drive gear (35) of the drive shaft (28) engages directly with a driven gear (36) on one of the rotor shafts (8, 9), forming the gear stage (37).

Abstract: A screw compressor includes a compressor main body, a male rotor having a screw-like male tooth shape and a female rotor having a screw-like female tooth shape meshing with the screw-like male tooth shape or the male rotor. The male and female motors are provided within the compressor main body. A motor casing is operably connected to the compressor main body, and a high speed electric motor provided within the motor casing. The motor includes a motor rotor, a motor stator and a motor shaft for driving at least one of the male and female rotors. A speed ratio of the motor shaft and the at least one of the male and female rotors driven by the motor shaft is in a range of 2:1 to 1:2.

Abstract: A fuel booster operable to compress a combustible fuel, the fuel booster comprising a compressor housing a compress rotor, and a seal assembly coupled to the compressor housing. The seal assembly and the compressor housing cooperate to at least partially define a hermetically sealed compressor chamber. A motor housing is coupled to the seal assembly. The motor housing and seal assembly cooperate to at least partially define a motor chamber that is sealed from the compressor chamber to prevent fluid flow therebetween. The fuel booster also includes a motor having a motor rotor and a motor stator. The motor rotor and the compressor rotor are contained within the compressor chamber. The motor rotor includes a cylindrical surface. The motor stator substantially surrounds the cylindrical surface and is contained within the motor chamber.

Abstract: A geared feed pump has a housing having a pump chamber in which a rotationally driven pair of gear wheels meshing with one another is disposed for pumping medium out of a suction chamber that communicates with a supply tank, along feed conduits, formed between the circumferential surface of the gear wheels and the circumferential walls of the pump chamber, into a pressure chamber. A drive shaft connected with one of the gear wheels via a coupling member is disposed inside the housing in a coupling chamber. The coupling chamber has a connection with the pressure chamber, so that lubrication of the coupling member is effected by the pumping medium.

Abstract: The compressor has two rotors (14, 16), which are rotatably mounted in a housing (10) by means of a shaft each, the rotors (14, 16) rotating without contact with the housing. The rotors (14, 16) consist of a powder-metallurgical Al—Si alloy, and the housing (10) consists essentially of aluminum.

Abstract: A vacuum pump has a casing having an inlet port and an outlet port, and a pair of confronting pump rotors which are provided inside the casing and synchronously rotatable for drawing in a gas from the inlet port and discharging the gas from the outlet port. A motor for rotating the confronting pump rotors is a permanent magnet motor having a stator and a motor rotor. The motor rotor has an iron core and permanent magnets disposed within the iron core.

Abstract: The invention concerns a metering gear pump comprising a set of gears supported and guided solely by the inner peripheral surface of the lobe of the chamber wherein they are housed. They do not comprise any shaft to act as support or guide, thereby enabling to reduce significantly useless spaced difficult to rinse when changing the product to be pumped. For the same purpose, the driving shaft is flexibly connected to the driving gear. Such arrangement provides the advantage of requiring only one single packing seal. Such a pump, connected to a drive motor and an encoder delivering a signal proportional to the number of pump cycles, enables to provide an accurate metering pump for numerous uses.

Abstract: The present invention provides an improved refrigerant compressor comprising an overall casing, an electric motor with a stator and a rotor which is mounted on a drive shaft, and a screw compressor. A compressor screw of the screw compressor is mounted on the drive shaft, which is rotatably mounted in the casing by a first radial bearing between the rotor and the compressor screw and a second radial bearing disposed on a side of the compressor screw lying opposite the first radial bearing. The drive shaft is mounted in the casing by a third radial bearing disposed on a side of the rotor lying opposite the first radial bearing. A portion of the drive shaft which extends between the first radial bearing and one of the second and third radial bearings being adapted to compensate for alignment errors between the three radial bearings.

Abstract: A roots compressor module has a roots compressor accommodating drive and driven rotors in a rotor chamber of a compressor housing, an electric motor arranged coaxially with the drive rotor and having a motor housing fixedly connected to the compressor housing, a first device supported on one of the compressor and motor housings, a discharge passage formed in the compressor housing and extending from a discharge side of the rotor chamber in a direction perpendicular to an axis of the drive rotor, and a communication passage connecting the discharge passage with the first device. The first device is located by a side of the electric motor, while the communication passage extends from the discharge passage toward the first device along the axial direction of the drive rotor.

Abstract: The invention concerns a gear pump with a pump body closed with a cover forming a cavity in which is provided a drive pinion, a driven pinion whose teeth cooperate with the drive pinion teeth, and two end shields arranged on either side of the driven pinion penetrating into a cavity provided in the pump body and the cover respectively, pressure being exerted on the outer surface of the end shields. The end shields each consist of a disc integral with one end of the driven pinion, the discs and the driven pinion being concentric, the discs covering the teeth of the driven pinion. The pressure exerted on the outer surface of the discs prevents them from being deformed such that practically no axial leakage zone is formed. Additionally, the discs can serve as guiding axis for the rotation of the driven pinion.

Abstract: An orbital fluid pumping mechanism (37) having an outer tube (12) and an inner member (14) positioned substantially concentrically within the outer tube. Helical lobes (18, 22) form sealed pumping chambers to move the fluid.

Abstract: The present invention aims to provide a vacuum pump allowing a reduced power, a lower inside gas temperature, and a reduced discharging time. The screw vacuum pump has a pair of screw rotors rotatively engaged with each other in a pump casing to discharge a gas along a longitudinal direction of the pump. Each rotor has three types of helical teeth serially located in a longitudinal direction of the rotor and being different from each other in theoretical displacement volume, and a bypass conduit communicating with a delivery side of the pump is connected via a first check valve to a first intermediate space defined between the first helical teeth and the second helical teeth and via a second check valve to a second intermediate space defined between the second helical teeth and the third helical teeth. The three types of helical teeth provide a ratio of 1.4 of a gas flow rate at the first stage to that at the second stage, a ratio of 1.

Abstract: A fuel feed pump according to the present invention improves its pump performance by making smaller side clearances in an axial direction at both sides of a pump element PE.

Abstract: A pump assembly including a pump, a pump frame and a motor, the pump including a pumping member which is mounted in a pump housing, relative rotation of the pumping member with respect to the pump housing causing pumping of fluid, and the motor including a rotor and a stator, operation of the motor causing rotation of the pumping member relative to the pump housing, wherein one or two of the stator, pumping member and pump housing is fixed relative to the pump frame, a resilient support part being provided between the pump frame and each of the other two or one of the stator, pumping member, and the pump housing, the resilient support part or parts permitting movement of the stator, pumping member or pump housing with respect to the pump frame.

Abstract: An oil pump is adapted to pump oil by utilizing the variation of a cavity formed between mutually inwardly engaging gear-teeth of a drive gear and a driven gear. An oil pressure relief groove has a certain shape and is disposed at an isolated portion of the oil pump housing between an oil intake groove and an oil discharge groove. The oil pressure relief groove is in fluid communication with the oil discharge groove and relieves pressure of the oil as it is compressed between the teeth of the gears.

Abstract: In a refrigerant pump of the present invention, a communication hole and an annular groove of a drive shaft and a groove in a cylinder bearing are constructed so that refrigerant liquid is supplied to a bearing section, and therefore the refrigerant liquid is positively supplied to the bearing section, thus making it possible to construct a favorable slide bearing against abrasion.

Abstract: A pump e.g. a screw pump, includes a main pumping element and a generally parallel auxiliary pumping element, and a pump housing, the main and auxiliary pumping elements interacting with each other and with an internal wall of an elongate pumping chamber of the housing as they relatively rotate to pump fluid from a first axial inlet end of the elongate chamber towards a second axial outlet end of the elongate chamber, and wherein the internal wall of the elongate pumping chamber includes at least one recess which extends along at least a substantial portion of the axial extent of the chamber between the inlet and outlet ends of the chamber, an adjacent pumping element being contactable with the chamber wall at discrete contact edges either side of the recess.

Abstract: A rotary blower with forced external air cooling having multiple interconnected and synchronized parallel multi-lobe rotors with the same number of straight lobes for propelling flow from a suction port to a discharge port of an inner casing without internal compression. The blower also has an outer cover with cooling air inlet and outlet openings and added centrifugal cooling fans mounted on the rotor shafts adjacent to the cooling air inlet openings for circulating cooling air through the space between the outer cover and the inner casing. The blower further utilizes wearable strip seal devices applied on the rotors for preventing internal leakage and accidental mechanical contact.

Abstract: Material transport catheters and methods for their use rely on rotation of an impeller within a catheter body and a clearing element for preventing buildup of materials at the opening of the catheter body. The impeller preferably comprises an inner tube or shaft having a helical rotor formed over an outer surface thereof. The clearing element may comprise a free end of a structure near the distal end of the catheter body for disrupting clot, wherein the free end of the structure extends into the distal opening of the catheter body to break up materials as the impeller is rotated. Alternatively, the clearing element may comprise a cutting member disposed at the distal opening of the catheter body.