US20060222553A1 - Rotary piston pump - Google Patents

Rotary piston pump Download PDF

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Publication number
US20060222553A1
US20060222553A1 US10/546,699 US54669905A US2006222553A1 US 20060222553 A1 US20060222553 A1 US 20060222553A1 US 54669905 A US54669905 A US 54669905A US 2006222553 A1 US2006222553 A1 US 2006222553A1
Authority
US
United States
Prior art keywords
cooling fluid
rotary piston
piston pump
bearing tube
rotor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/546,699
Other languages
English (en)
Inventor
Fritz-Martin Scholz
Jürgen Oswald
Herbert Vogt
Daniel Greiner
Wolf-Rüdiger Wagener
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gardner Denver Schopfheim GmbH
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Assigned to RIETSCHLE THOMAS SCHOPFHEIM GMBH reassignment RIETSCHLE THOMAS SCHOPFHEIM GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GREINER, DANIEL, OSWALD, JURGEN, SCHOLZ, FRITZ-MARTIN, VOGT, HERBERT, WAGENER, WOLF-RUDIGER
Publication of US20060222553A1 publication Critical patent/US20060222553A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/082—Details specially related to intermeshing engagement type pumps
    • F04C18/084—Toothed wheels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C21/00—Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00
    • F01C21/02—Arrangements of bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
    • F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/02—Lubrication; Lubricant separation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/04—Heating; Cooling; Heat insulation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2220/00—Application
    • F04C2220/10—Vacuum
    • F04C2220/12—Dry running
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2240/00—Components
    • F04C2240/50—Bearings

Definitions

  • This invention relates to a rotary piston pump, comprising at least two rotors with associated drive shafts, wherein for each rotor an associated bearing tube is provided, which extends into the associated rotor and through which the associated drive shaft passes, a first gap being provided between the inside of the rotor and the outside of the bearing tube.
  • This invention in particular relates to a dry-compression vacuum screw pump or a Roots pump of this kind.
  • the parallel drive shafts usually are synchronized with each other in a ratio of 1:1 by means of a transmission.
  • the speed of the shafts either corresponds to that of the motor, or the motor speed is increased by an additional pair of spur gears.
  • the contactless meshing counterrotating rotors form chambers which are transported from the suction side to the pressure side, thereby assuming a smaller volume, which is achieved by changing the pitch of the rotors.
  • the compression heat produced can be dissipated e.g. via the outside housing wall; it is also possible to cool the rotors from the inside, which involves, however, a considerable additional design effort.
  • the thermal expansion of the parts should be minimized, which can only be achieved by means of cooling, so that smaller gaps between the rotors can be achieved, which in turn leads to a reduction of the gap leakage.
  • cooling can not only increase the efficiency, but the media, e.g. gases, which as a result of the compression would be brought to temperatures above 200° C. without cooling, can be delivered far below this temperature.
  • lower temperatures also have an advantageous effect on the design and service life of the parts of the rotary piston pump.
  • the invention relates to a rotary piston pump with such overhung mounting of the rotors.
  • the bearing tube of each rotor extends into an axial opening in the same.
  • the bearing tube usually is stationarily mounted at one end, preferably by coupling to the pump housing.
  • the associated drive shaft which has a drive-side end and an end coupled to the rotor, then extends through the bearing tube.
  • the generic WO 97/01038 describes a complex cooling of the rotors, in which the bearing tubes themselves include cooling passages through which coolant flows.
  • radiant heat is said to be transferred from the rotor to the bearing tube through a gap between rotor and bearing tube.
  • Seal gas can also be introduced into the gap, which is provided for cooling and for protecting the bearing and drive region against the access of pumping medium or of substances contained in the pumping medium.
  • the first gap contains cooling fluid, i.e. cooling fluid is transported through the same, and is part of a cooling fluid circuit.
  • the first gap has a cooling fluid inlet and a spatially separate, i.e. physically separate, cooling fluid outlet.
  • cooling via the first gap is much more effective, as cooling fluid is introduced into the gap, which allows a good dissipation of heat directly at the rotor.
  • This cooling fluid is part of a cooling fluid circuit, so that cooler fluid is always supplied to the rotor. Due to the separate inlet and outlet, there is only one flow direction through the cooled gap portion, i.e. no dead spaces like a blind hole, into which cooling fluid must flow in and out again.
  • cooling passages provided in the wall of the bearing tube or in the drive shaft in accordance with the prior art can be omitted, which simplifies the manufacture and maintenance of the pump in accordance with the invention.
  • Additional tubes, pockets, cavities and the like inside the rotor can also be omitted.
  • a second gap is provided, which is part of the cooling fluid circuit. This means that the two gaps to be produced very easily are in flow connection with each other.
  • the cooling fluid circuit preferably is designed such that cooling fluid first flows into the second, radially inner gap and then from the same into the first gap.
  • the bearing tube has a stationarily mounted end and an opposite free end extending into the rotor.
  • the invention provides that at the stationarily mounted end the second gap has an associated cooling fluid inlet and at the axially opposite end a cooling fluid outlet, which is in flow connection with a cooling fluid inlet of the first gap at the free end of the bearing tube.
  • a connecting passage is provided between the two gaps.
  • the invention provides some more advantages. Whereas in the prior art, all bearings should be expensive, sealed, permanently lubricated bearings and expensive additional gaskets were desired, the invention goes the opposite way. It provides, for instance, that between the respective bearing tube and the associated drive shaft at least one bearing is mounted, through which the flow of cooling fluid passes completely or partially, so that the bearing is cooled and lubricated.
  • this can also be effected in at least one bearing between the bearing tube and the associated rotor.
  • bypasses for cooling fluid can be provided between the bearing(s) and the adjoining parts. These bypasses increase the flow rate, or if the bearing should be sealed contrary to what has been explained above, it allows the passage of cooling fluid in the vicinity of the corresponding bearing point.
  • the cooling fluid circuit preferably is open towards the cooling and lubricating fluid of the transmission.
  • a particular advantage of the invention consists in that the cooling and lubricating fluid of the transmission for driving the rotors also constitutes the cooling fluid of the rotors.
  • the hermetic sealing provided in the prior art thus can be omitted, and the entire pump has a much simpler design. In other words: that part of the interior of the transmission, which is filled with cooling and lubricating fluid, constitutes part of the cooling fluid circuit.
  • the simple design of the pump in accordance with the invention is also revealed by the fact that a cooling fluid pump driven by the transmission itself is accommodated in the transmission housing, which pump delivers the cooling fluid into the gap(s).
  • the drive shaft is designed without cooling passage at least in the vicinity of its drive-side end (transmission end), but in particular along its entire length, which reduces the production costs and increases the stability.
  • a reservoir for cooling fluid e.g. the transmission housing with the cooling and lubricating fluid contained therein, is in flow connection with the first or second gap via a passage located outside the drive shaft.
  • the rotary piston pump in accordance with the invention is designed free from seal gas.
  • FIG. 1 shows a longitudinal section through a first embodiment of the rotary piston pump of the invention, which is designed as vacuum screw pump;
  • FIG. 2 shows a longitudinal section through a second embodiment of the rotary piston pump of the invention, which is designed as vacuum screw pump;
  • FIG. 3 shows a longitudinal section through a bearing region of the rotors, which has been changed as compared to the preceding embodiments.
  • FIG. 4 shows an enlarged view of the framed region X as shown in FIG. 3 .
  • FIG. 1 shows a dry-compression rotary piston pump in the form of a vacuum screw pump, which on the vacuum side has a suction port 10 and on the pressure side a blow-off port 12 , which are both connected with each other by a working space 14 .
  • a working space 14 two parallel rotors 8 are accommodated, which have a helix 16 with a downwardly progressively decreasing pitch.
  • the rotors 8 are meshing with each other, rotate in opposite directions and form chambers 18 , which during the rotation of the rotors 8 are transported from the suction side to the pressure side, i.e. with a pump at rest from the top to the bottom, so that the pumping medium enclosed in the chambers is compressed towards the pressure side.
  • the two rotors 8 have a hollow interior, are mounted overhung, have the same geometry and the same structure inside also in terms of their bearing, so that for simplification purposes only the right-hand rotor 8 together with its bearing must be explained.
  • the rotor 8 has an axial through hole with an upper portion 20 of smaller diameter and an adjoining portion of larger diameter, which subsequently is defined by an inside 24 .
  • a drive shaft 26 is press-fit into the portion 20 , so that rotor and drive shaft 26 are coupled to each other for joint rotation.
  • a bearing tube 28 extends, which is stationarily mounted at a transmission housing 30 , namely with its so-called lower, stationarily mounted end 31 . Through this bearing tube 28 , the drive shaft 26 extends into the interior 34 of the transmission housing 30 .
  • a spiral bevel pinion 38 is connected with the drive shaft 26 , which pinion meshes with a spiral bevel gear 40 which in turn is firmly seated on a shaft 42 , which is rotated by a non-illustrated motor.
  • the two drive shafts 26 each have their own pair of spiral bevel pinions or gears 38 , 40 , but the spiral bevel gears 40 are mounted on a common shaft 42 .
  • the shaft 42 is in turn rotatably mounted in the transmission housing 30 .
  • the transmission arrangement is a so-called vertical shaft arrangement, in which the shaft 42 is perpendicular to the parallel drive shafts 26 .
  • the speed of the drive shafts 26 can be increased (the pitch circle of the spiral bevel gears 40 is larger than that of the spiral bevel pinions 38 ), but at the same time the direction of rotation of the drive shafts 26 is synchronized.
  • the peripheral speed of the gears coupled to the drive shafts 26 is decisive for the transmission noise.
  • the peripheral speed was dependent on the axial distance in accordance with the prior art. In the pump in accordance with the invention, this is not the case; here, the peripheral speed of the spiral bevel gears 40 and the spiral bevel pinions 38 is independent of the axial distance, and the diameter of the spiral bevel pinions 38 even is distinctly smaller than the axial distance between the drive shafts 26 .
  • Another advantage of the design of the invention consists in that with the same gears different axial distances can be realized, when different rotors 8 are being used.
  • the drive shaft 26 is positioned in the bearing tube 28 via a locating bearing 50 , which constitutes an open bearing, i.e. is not permanently lubricated and not sealed, and at the free upper end of the bearing tube 28 via a floating bearing 42 in the axial and radial directions.
  • the rotor 8 is also supported in the axial and peripheral directions.
  • the bearing 42 neither is sealed, but constitutes an open bearing.
  • each rotor For cooling each rotor 8 , each rotor has its own cooling fluid circuit, through which the cooling and lubricating fluid 60 in the interior of the transmission housing 30 is delivered, which is present for lubricating and cooling the gears provided therein.
  • the cooling and lubricating fluid 60 in the transmission housing constitutes a reservoir for the cooling fluid of the rotors 8 .
  • the cooling fluid circuit proceeds from the interior of the transmission housing 30 and extends through the open locating bearing 50 and/or a bypass 32 provided there, i.e. a passage provided outside the drive shaft 26 .
  • a cylindrical annular gap is obtained, which extends up to the bearing 42 .
  • this gap 62 is referred to as radially inner, second gap. It is in flow connection with a first, radially outer gap 64 , which is formed between the inside 24 of the rotor 8 and the outside of the bearing tube 28 .
  • the flow connection between the gap 62 and the gap 64 is effected via the open floating bearing 42 , an optionally provided bypass 70 as well as groove-like connecting passages or an annular gap 80 between the end face of the free end of the bearing tube 28 and the adjoining, end-face wall of the rotor 8 .
  • This connecting passage 80 then leads to the cooling fluid inlet 81 (upper end) of the first gap 64 .
  • the cooling fluid outlet 83 of the first gap 64 is provided at its lower end, where a passage 90 leads into a collecting ring and from there into a non-illustrated oil sump or into the interior 34 of the transmission.
  • the cooling fluid thus flows into said gap, after having possibly cooled and lubricated the bearing 50 , flows upwards to the fluid outlet towards the bearing 42 and/or the bypass 70 , in order to then reach the gap 64 via the connecting passage 80 , where it is pressed against the inside 24 of the rotor by the existing centrifugal forces and where shear flows are produced.
  • the rotors 8 which are heated during compression, largely dissipate the heat to the cooling fluid, which then flows to the cooling fluid source, where it is mixed with the cold cooling fluid 60 .
  • the illustrated pump is also characterized by a very simple sealing. On the vacuum side, no sealing is required at all. Seals 92 are only required on the pressure side of the vacuum pump between the lower end of the rotors 8 and the transmission. But since there is a connection there with the blow-off port 12 of the pump and hence with the atmosphere, the seals 92 never are acted on with pressure, which increases their service life and their sealing performance. Seal gas likewise can be omitted.
  • FIGS. 2 to 4 substantially correspond to the one as shown in FIG. 1 , so that subsequently only the differences will be discussed. It should be emphasized that these distinguishing features discussed below can also be combined with each other as desired within the scope of the illustrated embodiments.
  • a shaft extension 100 is provided as drive for an integrated cooling fluid pump 110 , which is accommodated in the interior 34 of the transmission and pumps the cooling fluid 60 to each of the second gaps 62 .
  • Corresponding conduits are designated with 120 .
  • a rib 130 of the transmission housing 30 in which the shaft 42 is mounted in addition.
  • a corresponding locating bearing is designated with 132 .
  • the locating bearing 132 between the spiral bevel gears 40 is advantageous, because under the supply of heat the shaft 42 can freely expand towards both axial ends.
  • an open floating bearing 150 is once more provided between the inside 24 and the bearing tube 28 at the lower end of each rotor 8 , by means of which bearing the corresponding rotor 8 is additionally stabilized at the lower end.
  • the bearing 150 preferably is a plain bearing of relatively simple design, which is bypassed by a part of the cooling fluid through a bypass 160 in the form of a longitudinal groove in the bearing tube 28 .
  • the cooling fluid preferably is oil.
  • the design with the cooling circuit in the gaps 62 , 64 can also be provided in a Roots pump.
  • the pump of the invention is characterized by a very simple structure, by the lack of complex passages inside the rotor, the bearing tube and the drive shaft, and by very large surfaces, which serve a fast transfer of heat for dissipating the heat.
  • the housing 170 which surrounds the rotors 8 , can of course also include an additional cooling passage 180 with cooling fluid.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
US10/546,699 2003-02-24 2004-02-23 Rotary piston pump Abandoned US20060222553A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE20302989.5 2003-02-24
DE20302989U DE20302989U1 (de) 2003-02-24 2003-02-24 Drehkolbenpumpe
PCT/EP2004/001769 WO2004074690A1 (de) 2003-02-24 2004-02-23 Drehkolbenpumpe

Publications (1)

Publication Number Publication Date
US20060222553A1 true US20060222553A1 (en) 2006-10-05

Family

ID=32695287

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/546,699 Abandoned US20060222553A1 (en) 2003-02-24 2004-02-23 Rotary piston pump

Country Status (8)

Country Link
US (1) US20060222553A1 (de)
EP (1) EP1601877A1 (de)
JP (1) JP2006518827A (de)
KR (1) KR20050103954A (de)
CN (1) CN1768206A (de)
AU (1) AU2004213587A1 (de)
DE (1) DE20302989U1 (de)
WO (1) WO2004074690A1 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060269424A1 (en) * 2005-05-27 2006-11-30 Michael Henry North Vacuum pump
US20150167541A1 (en) * 2013-10-16 2015-06-18 John Malcolm Gray Supercharger
WO2016157450A1 (ja) * 2015-03-31 2016-10-06 株式会社日立産機システム ガス圧縮機
US11066967B2 (en) * 2018-04-24 2021-07-20 Nidec Gpm Gmbh Controllable lubricating oil delivery system for internal combustion engines
US11293433B2 (en) 2017-06-27 2022-04-05 Vitesco Technologies GmbH Screw spindle pump, fuel pump assembly, and fuel pump unit

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005012040A1 (de) * 2005-03-16 2006-09-21 Gebr. Becker Gmbh & Co Kg Rotor und Schraubenvakuumpumpe
ATE498071T1 (de) 2005-12-08 2011-02-15 Ghh Rand Schraubenkompressoren Schraubenkompressor
JP2007170341A (ja) * 2005-12-26 2007-07-05 Toyota Industries Corp スクリュー式流体機械
CN102192151A (zh) * 2011-05-19 2011-09-21 台州市星光真空设备制造有限公司 内冷式真空泵
CN102410219A (zh) * 2011-11-24 2012-04-11 威海智德真空科技有限公司 一种立式干式螺杆真空泵
CN112012931B (zh) * 2020-09-04 2022-05-24 浙江思科瑞真空技术有限公司 一种泵转子的冷却方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2938664A (en) * 1955-01-17 1960-05-31 Leybold S Nachfolger Fa E Pump
US4983106A (en) * 1988-10-07 1991-01-08 Societe Anonyme Dite: Alcatel Cit Rotary screw machine with multiple chambers in casing for lubrication-coding fluid
US5924855A (en) * 1995-06-21 1999-07-20 Sihi Industry Consult Gmbh Screw compressor with cooling
US20020057979A1 (en) * 1999-06-16 2002-05-16 Schofield Nigel Paul Screw pumps
US6497563B1 (en) * 1998-08-29 2002-12-24 Ralf Steffens Dry-compressing screw pump having cooling medium through hollow rotor spindles
US20030147764A1 (en) * 1999-12-27 2003-08-07 Hartmut Kreihn Screw vacuum pump with a coolant circuit

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2938664A (en) * 1955-01-17 1960-05-31 Leybold S Nachfolger Fa E Pump
US4983106A (en) * 1988-10-07 1991-01-08 Societe Anonyme Dite: Alcatel Cit Rotary screw machine with multiple chambers in casing for lubrication-coding fluid
US5924855A (en) * 1995-06-21 1999-07-20 Sihi Industry Consult Gmbh Screw compressor with cooling
US6497563B1 (en) * 1998-08-29 2002-12-24 Ralf Steffens Dry-compressing screw pump having cooling medium through hollow rotor spindles
US20020057979A1 (en) * 1999-06-16 2002-05-16 Schofield Nigel Paul Screw pumps
US20030147764A1 (en) * 1999-12-27 2003-08-07 Hartmut Kreihn Screw vacuum pump with a coolant circuit

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060269424A1 (en) * 2005-05-27 2006-11-30 Michael Henry North Vacuum pump
US20150167541A1 (en) * 2013-10-16 2015-06-18 John Malcolm Gray Supercharger
US10006340B2 (en) * 2013-10-16 2018-06-26 John Malcolm Gray Supercharger
WO2016157450A1 (ja) * 2015-03-31 2016-10-06 株式会社日立産機システム ガス圧縮機
JPWO2016157450A1 (ja) * 2015-03-31 2017-12-07 株式会社日立産機システム ガス圧縮機
US11293433B2 (en) 2017-06-27 2022-04-05 Vitesco Technologies GmbH Screw spindle pump, fuel pump assembly, and fuel pump unit
US11066967B2 (en) * 2018-04-24 2021-07-20 Nidec Gpm Gmbh Controllable lubricating oil delivery system for internal combustion engines

Also Published As

Publication number Publication date
WO2004074690A1 (de) 2004-09-02
EP1601877A1 (de) 2005-12-07
AU2004213587A1 (en) 2004-09-02
KR20050103954A (ko) 2005-11-01
JP2006518827A (ja) 2006-08-17
DE20302989U1 (de) 2004-07-08
CN1768206A (zh) 2006-05-03

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AS Assignment

Owner name: RIETSCHLE THOMAS SCHOPFHEIM GMBH, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SCHOLZ, FRITZ-MARTIN;OSWALD, JURGEN;VOGT, HERBERT;AND OTHERS;REEL/FRAME:016795/0926

Effective date: 20050721

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION