Positioned At Passage End (e.g., Stripper Seal, Etc.) Patents (Class 415/55.4)
  • Patent number: 11371515
    Abstract: In accordance with one aspect the present invention may comprise a regenerative blower comprising: a housing, a first port and second port in the housing, an airflow channel extending between the first and second ports for airflow between the ports, an impeller rotatable in an impeller channel to promote airflow in the airflow channel from the first port to the second port, a motor to drive the impeller, and an interrupter between the first and second ports to limit airflow from the second port to the first port.
    Type: Grant
    Filed: February 11, 2018
    Date of Patent: June 28, 2022
    Assignee: Fisher & Paykel Healthcare Limited
    Inventors: Donald Roy Kuriger, Johannes Nicolaas Bothma
  • Patent number: 11248615
    Abstract: The invention relates to a side-channel machine having a housing (4a), located in the housing (4a) a side-channel (28) for guiding a gas, and at least one gas inlet opening (34) which is formed in the housing (4a) and is fluidically connected to the side-channel (28). Furthermore, the side-channel machine has at least one gas inlet pipe (29a) which connects to the at least one gas inlet opening (34). The side-channel machine further comprises at least one gas outlet opening (33) and at least one gas outlet pipe (31a) which connects to the at least one gas outlet opening (33). Furthermore, the side-channel machine has an impeller that can be made to rotate in the housing (4a), with impeller blades, which bound impeller cells arranged in the side-channel (28), for delivering the gas in the impeller cells from the at least one gas inlet opening (34) to the at least one gas outlet opening (33).
    Type: Grant
    Filed: September 3, 2020
    Date of Patent: February 15, 2022
    Assignee: GARDNER DENVER DEUTSCHLAND GMBH
    Inventors: Rudi Dittmar, Peter Fischer
  • Patent number: 10767654
    Abstract: The invention relates to a side-channel machine having a housing, located in the housing a side-channel for guiding a gas, and at least one gas inlet opening which is formed in the housing and is fluidically connected to the side-channel. Furthermore, the side-channel machine has at least one gas inlet pipe which connects to the at least one gas inlet opening. The side-channel machine further comprises at least one gas outlet opening and at least one gas outlet pipe which connects to the at least one gas outlet opening. Furthermore, the side-channel machine has an impeller that can be made to rotate in the housing, with impeller blades, which bound impeller cells arranged in the side-channel, for delivering the gas in the impeller cells from the at least one gas inlet opening to the at least one gas outlet opening. The side-channel machine further has at least one interrupter arranged between the at least one gas inlet opening and the at least one gas outlet opening.
    Type: Grant
    Filed: July 15, 2016
    Date of Patent: September 8, 2020
    Assignee: GARDNER DENVER DEUTSCHLAND GMBH
    Inventors: Rudi Dittmar, Peter Fischer
  • Patent number: 10718335
    Abstract: A turbomachine includes a housing and an electric motor in the housing. The electric motor has a shaft, a stator, and a rotor on the shaft. At least one impeller is arranged in a pump housing and driven by the shaft, the impeller having at least one ring of rotor blades delimiting a ring of blade chambers. A side channel is arranged in the pump housing opposite the ring of blade chambers and extends from the pump inlet as far as the pump outlet. A ramp is arranged at an end of the side channel in a radially inner half of the side channel. The ramp starts from a channel bottom, rises in a flow direction as far as the height of the pump housing wall, and merges with its radially outer half into the pump outlet.
    Type: Grant
    Filed: November 28, 2013
    Date of Patent: July 21, 2020
    Assignee: Continental Automotive GmbH
    Inventors: Klaus-Werner Bender, Peter Köppler
  • Patent number: 10662970
    Abstract: An impeller may include a plurality of blades disposed along a rotation direction in an outer circumferential portion of at least one end surface of two end surfaces of the impeller; a plurality of blade grooves; and an outer circumferential wall disposed at an outer circumferential edge and closing the plurality of grooves. The housing may include an opposing groove opposing a blade groove region and extending along the rotation direction of the impeller. In a plan view of the one end surface of the two end surfaces of the impeller, each of the plurality of the blades may be curved, and a central portion of each of the blades may be positioned frontward in the rotation direction of the impeller than both ends of the blade.
    Type: Grant
    Filed: November 2, 2016
    Date of Patent: May 26, 2020
    Assignee: AISAN KOGYO KABUSHIKI KAISHA
    Inventor: Eiji Nakamura
  • Patent number: 9297276
    Abstract: A side channel blower includes a housing comprising a substantially tangential outlet. A housing cover comprises an axial inlet. At least one conveying duct is configured so that the axial inlet fluidly communicates with the outlet. An impeller is driven by a drive unit. The impeller is rotatably supported in the housing and comprises conveying blades which cooperate with the at least one conveying duct. An interruption region is arranged between the outlet and the axial inlet. The interruption region comprises a radially limiting wall and interrupts the at least one conveying duct in a circumferential direction. A first recess is arranged in the radially limiting wall of the interruption region downstream of the outlet. Further recesses are arranged in the interruption region before the axial inlet and after the outlet. A smallest distance between the further recesses is 0.5 to 3 times a distance between two conveying blades.
    Type: Grant
    Filed: August 31, 2011
    Date of Patent: March 29, 2016
    Assignee: PIERBURG GMBH
    Inventors: Berthold Herrmann, Rainer Peters
  • Patent number: 8356969
    Abstract: Pumping units are known to have an inlet channel, opening out into a pumping channel and tapering from an inlet cross section to an outlet into the pumping channel with an outlet cross-section. The flow is deflected through ninety degrees on entry to the pumping channel which induces strong swirling. The transition from the inlet channel into the pumping channel is not optimal for flow. This effect reduces the efficiency of the pumping unit. The inlet flow into the pumping channel is improved in the pumping unit according to the invention and hence efficiency is improved. According to the invention, the outlet is essentially provided in a first quadrant with relation to the inlet cross section and the tapering of the inlet channel essentially occurs in the other three quadrants. The tapering wall of the inlet channel is formed by a plane-generating shape which goes around from one side of the outlet to the other side of the outlet and is shaped to be increasingly flat relative to a plane of the outlet.
    Type: Grant
    Filed: September 17, 2007
    Date of Patent: January 22, 2013
    Assignee: Robert Bosch GmbH
    Inventors: Benjin Luo, Joerg Sigrist, Andreas Gutscher
  • Patent number: 7766604
    Abstract: Fuel pump (10)comprises a casing (18) and an impeller (20). A group of concavities (20a) are formed in an upper or a lower face of the impeller. A groove (24) communicating a discharge hole (25) is formed in a inner face of the casing. The groove has an opening portion (27e) that directly communicates with the discharge hole. The opening portion is shaped so as to extend in the rotation direction of the impeller, within a span extending from a position corresponding to substantially the central position of the concavities of the impeller, in the radial direction thereof, to a position corresponding to substantially the outer peripheral edge of the concavities of the impeller. The opening portion is be formed so as to extend in the rotation direction of the impeller beyond the position (29b) where the inner peripheral edge connects therewith.
    Type: Grant
    Filed: April 10, 2006
    Date of Patent: August 3, 2010
    Assignee: Aisan Kogyo Kabushiki Kaisha
    Inventors: Yoshihiko Honda, Sumito Takeda, Shinichi Fujii
  • Patent number: 7748381
    Abstract: A portable cooling or respiratory blower system of the type carried by a user's body includes a housing having two air flow chambers. An impeller is rotatably disposed between the two air flow chambers and includes a base wall that places the two air flow chambers in non-fluidic communication when the impeller is rotated. A separate plurality of blades is provided on each side of the base wall.
    Type: Grant
    Filed: December 9, 2005
    Date of Patent: July 6, 2010
    Assignee: 3M Innovative Properties Company
    Inventors: Lisa M. Croll, Pierre Legare, David E. Livingstone
  • Patent number: 7722311
    Abstract: A pump having a housing with a torus and a stripper region. The stripper region has a housing groove formed on the surface of the stripper region. The housing groove has a surface forming a length, width and depth of the groove. The pump also has a cover connectable to the housing. The cover extends over the housing groove formed on the surface of the stripper region. An impeller has a plurality of vanes that extend radially outward from an impeller frame, wherein the impeller is rotatably positioned between the housing. The cover and the plurality of vanes are positioned in operable relation to said housing groove.
    Type: Grant
    Filed: November 30, 2006
    Date of Patent: May 25, 2010
    Assignee: BorgWarner Inc.
    Inventors: Todd R. Peterson, Ketan Adhvaryu, Ramon B. Jaramillo
  • Patent number: 7628577
    Abstract: A vacuum pump includes a housing having an inlet port and an exhaust port, at least one molecular drag stage within the housing, the molecular drag stage including a rotor and a stator that defines a tangential flow channel which opens onto a surface of the rotor, and a motor that rotates the rotor so that gas is pumped from the inlet port to the exhaust port. The stator defines one or more obstructions in the channel. The obstructions alter gas flow through the channel and produce turbulence under viscous or partially viscous flow conditions.
    Type: Grant
    Filed: August 31, 2006
    Date of Patent: December 8, 2009
    Assignee: Varian, S.p.A.
    Inventor: Marsbed Hablanian
  • Patent number: 7244094
    Abstract: An impeller pump for a fluid includes a rotary impeller (10; 20) and a pump casing (4). The pump casing defines a first pump channel (51) and a second pump channel (71). The impeller is disposed within the pump casing and opposes to the first pump channel and the second pump channel, respectively. The fluid discharged from the first pump channel and the fluid discharged from the second pump channel converge at a convergence channel (62). A pulsation canceling device serves to cancel pulsations of the fluid discharged from the first pump channel and the second pump channel, respectively. An impact reducing device (155, 175; 357; 455, 457; 555, 557) serves to reduce impacts produced by at least one of the flow of the fluid from the first pump channel and the flow of the fluid from the second channel.
    Type: Grant
    Filed: July 29, 2003
    Date of Patent: July 17, 2007
    Assignee: Aisan Kogyo Kabushiki Kaisha
    Inventors: Satoshi Miura, Masaki Ikeya
  • Patent number: 7217086
    Abstract: A cooling fluid pump includes a casing having a cylindrical pump chamber inside and an outer surface, the pump chamber having an inner surface, an impeller mounted rotatably inside the pump chamber and having a number of pump vanes, the impeller further having an axial end, a fluid path defined around the impeller in the pump chamber so that a fluid flows through the fluid path upon rotation of the impeller, a discharge port formed in the casing for discharging the fluid inside the fluid path and a suction port formed in the casing for suctioning the fluid into the fluid path upon rotation of the impeller, a protrusion formed on a portion of the inner surface of the pump chamber opposed to the axial end of the impeller, thereby separating the fluid discharged from the discharge port and the fluid suctioned from the suction port as well as pressuring the fluid flowing in the fluid path, and a heat receiving portion formed on a part of the outer surface of the casing overlapping the protrusion.
    Type: Grant
    Filed: August 30, 2005
    Date of Patent: May 15, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Katsuya Seko, Kenichi Ito
  • Patent number: 7198455
    Abstract: In a pumping arrangement for a chamber, a regenerative pumping mechanism comprises a rotor and a stator having an annular channel within which rotor blades rotate to urge fluid along the channel. The channel has a stripper, a channel inlet positioned adjacent one end of the stripper and through which fluid from the chamber enters the channel, and a channel outlet positioned adjacent the other end of the stripper and through which pressurised fluid leaves the channel. The stator further comprises a fluid bypass in the form of a bore having an inlet and an outlet on either side of the stripper. A valve allows fluid entering the channel to selectively diverted through the bore to the channel outlet. This can allow the performance of the pump to be varied without changing the speed of rotation of the rotor, and thus allow the pressure in the chamber to be accurately controlled.
    Type: Grant
    Filed: November 17, 2004
    Date of Patent: April 3, 2007
    Assignee: The BOC Group plc
    Inventor: Stephen Edward Downham
  • Patent number: 7175383
    Abstract: A regenerative fluid pump (10) comprises a rotor having rotor blades for compressing fluid on two fluid flow paths, the first of which extends between a first pump inlet (12a) and a first pump outlet (14a), and a second of which extends between second pump inlet (12b) and a second pump outlet (14b). The pump comprises a stator comprising a plurality of concentric channels (16), each of which comprises: a pumping channel portion (18) along which said rotor blades move for compressing said fluid between an inlet and an outlet of the pumping channel; and a stripper channel portion (20) (shown in broken lines) which allows movement of said rotor blades from said outlet to said inlet of the pumping channel portion. Each concentric channel (16) comprises two pumping channel portions (18) and two stripper channel portions (20).
    Type: Grant
    Filed: July 4, 2003
    Date of Patent: February 13, 2007
    Assignee: The BOC Group plc
    Inventors: Ian David Stones, Ingo Graham
  • Patent number: 7165931
    Abstract: A molecular drag vacuum pump configured for pumping a gas stream from an inlet to an outlet, the pump including a high-speed spinning disk or rotor disposed within a housing. A passageway is formed inside the housing adjacent the disk, and gas comes in contact with surfaces of the spinning disk in successive stages, conformable wipers being disposed adjacent the spinning disk to direct the gas stream to the successive stages. The disk can be powered by an integrated motor, comprising permanent magnets associated with the disk and cooperating coils associated with the housing. The wipers can include parallel ridges on a contacting face to facilitate creation of a conformable fit with the rotor. Seal rings may be disposed against the disk between gas passageways to reduce leakage therebetween, and the pump may include regenerative pumping pockets to help prevent backflow. The housing may have a modular configuration to allow two or more pump modules to be connected and operate in series.
    Type: Grant
    Filed: January 3, 2005
    Date of Patent: January 23, 2007
    Assignee: Sarcos Investments LC
    Inventors: Marc Olivier, Stephen C. Jacobsen, David Knutti
  • Patent number: 7037066
    Abstract: A multiple-channel, single stage, turbine fuel pump impeller, preferably for use with vehicle fuel delivery systems. The impeller includes independent inner and outer vane arrays concentrically disposed to one another and radially spaced apart. The inner and outer vane arrays respectively communicate with independent inner and outer pumping chambers, each of which receives fuel at an inlet end from a common fuel inlet passage and expels fuel at an outlet end into a common fuel outlet passage. Furthermore, the pumping efficiency and overall performance of the pump is increased by utilizing an impeller where each vane: i) includes a linear root segment and a curved tip segment, ii) has a V-shape that opens in the direction of rotation, and iii) includes a rounded surface or radius on a trailing edge, to name but a few of the attributes of the vanes.
    Type: Grant
    Filed: June 10, 2003
    Date of Patent: May 2, 2006
    Assignee: TI Group Automotive Systems, L.L.C.
    Inventor: Glenn A. Moss
  • Patent number: 6942446
    Abstract: The invention relates to a feed pump (2) that is configured as a side-channel pump with a plurality of identically designed feed chambers (6, 7) with outlet channels (22, 23) that are disposed opposite one another, thereby eliminating the radial forces acting upon the impeller (4) of the feed pump (2). The feed pump (2) according to the invention is especially wear-free and has a very high degree of efficiency.
    Type: Grant
    Filed: December 13, 2001
    Date of Patent: September 13, 2005
    Assignee: Siemens Aktiegesellschaft
    Inventors: Zlatko Penzar, Hans-Dieter Wilhelm
  • Patent number: 6932562
    Abstract: A single stage, dual channel turbine fuel pump for use in a vehicle fuel delivery system, generally including a lower casing, an upper casing, an impeller and a motor. Both the lower and upper casings have a pair of concentric, annular grooves formed on their surfaces, where the two lower annular grooves are in fluid communication with a fuel passage inlet and the two upper annular grooves are in fluid communication with a fuel passage outlet. Rotation of the impeller causes a portion of the incoming fuel to be diverted into an inner lower groove and another portion into an outer lower groove. Once in the lower grooves, the fuel communicates with other parts of the pumping chamber such that it fills the upper grooves as well. Generally independent, helical fuel flow patterns are formed which cause the fuel to become pressurized as it flows from the inlet to the outlet.
    Type: Grant
    Filed: June 12, 2003
    Date of Patent: August 23, 2005
    Assignee: TI Group Automotive Systems, L.L.C.
    Inventor: Joseph M. Ross
  • Patent number: 6890144
    Abstract: A regenerative fuel pump comprising a housing, a pump cover having a first flow channel formed therein, a pump body having a second flow channel formed therein whereby the first flow channel and the second flow channel define a pumping chamber, and an impeller mounted between the pump cover and pump body and including a plurality of vanes spaced circumferentially about the impeller and defining a plurality of vane grooves. The vanes are spaced un-evenly in a non-repeating pattern about the impeller. The first and second flow channels each include an inlet end, an outlet end, and a stripper area defined as the area between the inlet end and the outlet end extending from the inlet end away from the flow channel. Each of the stripper areas including a plurality of grooves formed therein adapted to dampen pressure pulsations within the pumping chamber.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: May 10, 2005
    Assignee: Visteon Global Technologies, Inc.
    Inventors: DeQuan Yu, Stephen Thomas Kempfer, Paul Edward Fisher, Norman Nelson Krieger, David M. Dokas
  • Patent number: 6877949
    Abstract: A pumping stage for a vacuum pump, has an improved geometry allowing an optimum trade-off to be achieved between the exhaust pressure and the pumping rate attained in that stage. In the pumping stage (1) the axial extension that is the height of the pumping channel (3) varies along the circumference of the channel (3) between the inlet port (13) and the outlet port (15).
    Type: Grant
    Filed: May 5, 2003
    Date of Patent: April 12, 2005
    Assignee: Varian, S.p.A.
    Inventors: Roberto Cerruti, Silvio Giors
  • Patent number: 6799941
    Abstract: A turbine fuel pump assembly draws fuel from a reservoir and supplies that fuel to a combustion engine. The assembly includes an electric motor which drives a fuel pump, all of which is supported in a sleeve. The fuel pump has a guide ring which has a stripper segment for stripping or shearing fuel off of the vanes of an impeller and redirecting the fuel through an outlet port of the fuel pump. The turbine fuel pump assembly can be easily calibrated for improved pumping efficiency via a calibration ring tool which plastically deforms the sleeve externally by producing a dimple upon the sleeve and a corresponding interior protuberance which bears radially inward against a trailing segment of the guide ring to calibrate or move the cantilevered stripper segment against the impeller to a point where fuel stripping is improved and flow through the pump is optimized.
    Type: Grant
    Filed: June 19, 2002
    Date of Patent: October 5, 2004
    Assignee: TI Group Automotive Systems, L.L.C.
    Inventor: Bradley L. Uffelman
  • Patent number: 6715986
    Abstract: A fuel pump for discharging a desired amount of fuel during vapor generation has a pump cover and a pump casing which rotatably accommodates an impeller. A pressure difference is caused in the vicinity of each impeller vane groove by fluid friction as the impeller rotates. Such a pressure difference repeatedly occurs with respect to each of the vane grooves, causing the pressurization of fuel in a pump channel formed along an outer periphery of the impeller to pump fuel to a motor chamber. An introduction groove of the pump channel formed on the pump cover side has a first vapor chamber outwardly extending in the radial direction of the impeller. Another pump channel introduction groove formed on the pump casing side has a second vapor chamber above the impeller. The first and second vapor chambers permit the removal of vapor in fuel fed from the fuel suction port.
    Type: Grant
    Filed: March 15, 2002
    Date of Patent: April 6, 2004
    Assignee: Denso Corporation
    Inventor: Hiroaki Takei
  • Publication number: 20040062634
    Abstract: A regenerative fuel pump comprising a housing, a pump cover having a first flow channel formed therein, a pump body having a second flow channel formed therein whereby the first flow channel and the second flow channel define a pumping chamber, and an impeller mounted between the pump cover and pump body and including a plurality of vanes spaced circumferentially about the impeller and defining a plurality of vane grooves. The vanes are spaced un-evenly in a non-repeating pattern about the impeller. The first and second flow channels each include an inlet end, an outlet end, and a stripper area defined as the area between the inlet end and the outlet end extending from the inlet end away from the flow channel. Each of the stripper areas including a plurality of grooves formed therein adapted to dampen pressure pulsations within the pumping chamber.
    Type: Application
    Filed: September 27, 2002
    Publication date: April 1, 2004
    Applicant: Visteon Global Technologies, Inc.
    Inventors: DeQuan Yu, Stephen Thomas Kempfer, Paul Edward Fisher, Norman Nelson Krieger, David M. Dokas
  • Patent number: 6676367
    Abstract: A regenerative fluid dynamic machine, typically a blower or compressor, includes an impeller (1) with fixedly attached blades (6) which may be radial or curved in a general convex fashion facing forward in the direction of turning. The impeller is enclosed in a housing which, together with the shaped profile of the rotor flank/s defines a toroidal passage (7) between inlet an outlet ports, fluid flow in said passage/s following a path which forms a spiral centred generally within the cross section of the passage, said housing may be provided with slideable side walls that are made to contact and expand the width of said toroidal passage to change the operation of the compressor so as to meet the requirements of fluid delivery or pressure. A preferred option is also proposed that will achieve a superior result through variations to the circumference span of the inlet passage.
    Type: Grant
    Filed: October 18, 2001
    Date of Patent: January 13, 2004
    Inventor: Norman Moss
  • Publication number: 20030185668
    Abstract: A turbine fuel pump assembly draws fuel from a reservoir and supplies that fuel to a combustion engine. The assembly includes an electric motor which drives a fuel pump, all of which is supported in a sleeve. The fuel pump has a guide ring which has a stripper segment for stripping or shearing fuel off of the vanes of an impeller and redirecting the fuel through an outlet port of the fuel pump. The turbine fuel pump assembly can be easily calibrated for improved pumping efficiency via a calibration ring tool which plastically deforms the sleeve externally by producing a dimple upon the sleeve and a corresponding interior protuberance which bears radially inward against a trailing segment of the guide ring to calibrate or move the cantilevered stripper segment against the impeller to a point where fuel stripping is improved and flow through the pump is optimized.
    Type: Application
    Filed: June 19, 2002
    Publication date: October 2, 2003
    Inventor: Bradley L. Uffelman
  • Publication number: 20030077164
    Abstract: A regenerative fluid dynamic machine, typically a blower or compressor, includes an impeller (1) with fixedly attached blades (6) which may be radial or curved in a general convex fashion facing forward in the direction of turning. The impeller is enclosed in a housing which, together with the shaped profile of the rotor flank/s defines a toroidal passage (7) between inlet an outlet ports, fluid flow in said passage/s following a path which forms a spiral centred generally within the cross section of the passage, said housing being provided with slideable side walls that are made to contract and expand the width of said toroidal passage to change the operation of the compressor so as to meet the requirements of fluid delivery or pressure. Another resort is also proposed that will achieve a similar result through variations to the circumference span of the inlet passage.
    Type: Application
    Filed: October 18, 2001
    Publication date: April 24, 2003
    Inventor: Norman Moss
  • Patent number: 6499941
    Abstract: A fuel pump for a vehicle includes a pump section having a flow channel and a rotatable impeller cooperating with said flow channel to pump fuel therethrough. The fuel pump also includes a motor section disposed adjacent the pump section and having a motor to rotate the impeller. The fuel pump further includes an outlet section disposed adjacent the motor section to allow pumped fuel to exit the fuel pump. The pump section includes a mechanism for minimizing leakage of fuel from the flow channel radially and equalizing pressure across a sealing surface of the impeller.
    Type: Grant
    Filed: August 31, 2000
    Date of Patent: December 31, 2002
    Assignee: Delphi Technologies, Inc.
    Inventor: John Gardner Fischer
  • Publication number: 20020131860
    Abstract: A fuel pump for discharging a desired amount of fuel during vapor generation has a pump cover and a pump casing which rotatably accommodates an impeller. A pressure difference is caused in the vicinity of each impeller vane groove by fluid friction as the impeller rotates. Such a pressure difference repeatedly occurs with respect to each of the vane grooves, causing the pressurization of fuel in a pump channel formed along an outer periphery of the impeller to pump fuel to a motor chamber. An introduction groove of the pump channel formed on the pump cover side has a first vapor chamber outwardly extending in the radial direction of the impeller. Another pump channel introduction groove formed on the pump casing side has a second vapor chamber above the impeller. The first and second vapor chambers permit the removal of vapor in fuel fed from the fuel suction port.
    Type: Application
    Filed: March 15, 2002
    Publication date: September 19, 2002
    Inventor: Hiroaki Takei
  • Patent number: 6336788
    Abstract: An impeller 16 has a plurality of blade grooves 16a formed along a perimeter thereof. A pump casing 17 has an inlet port 22, a discharge port 24, a first circumferential groove 20 contiguous with the inlet port 22, a second circumferential groove contiguous with the discharge port 24 and a partition 25 between a groove inlet portion 23 and the discharge port 24. An opening end face of the discharge port 24 on the side of the pump casing 17 that faces the impeller has a tapered portion 24a and a damping portion 24b. The tapered portion 24a has an opening width W that gradually decreases along the direction of rotation of the impeller 16. The damping portion 24b has an opening width that is substantially constant along the direction of rotation of the impeller. In one embodiment, a corner portion, which is defined by wall surfaces 24c, 24d defining the tapered portion 24a and the damping portion 24b of the discharge port 24, respectively, and a lower surface 9a of the pump casing 17, is chamfered.
    Type: Grant
    Filed: May 22, 2000
    Date of Patent: January 8, 2002
    Assignee: Aisan Kogyo Kabushiki Kaisha
    Inventors: Shinichi Fujii, Seiji Murase