US3817667A - Rotary-piston machine - Google Patents

Rotary-piston machine Download PDF

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Publication number
US3817667A
US3817667A US00228251A US22825172A US3817667A US 3817667 A US3817667 A US 3817667A US 00228251 A US00228251 A US 00228251A US 22825172 A US22825172 A US 22825172A US 3817667 A US3817667 A US 3817667A
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United States
Prior art keywords
pair
circle
plane
lying
impeller
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Expired - Lifetime
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US00228251A
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English (en)
Inventor
C Hubrich
C Winkelstrater
H Burgener
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Gebr Winkelstraeter GmbH
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Gebr Winkelstraeter GmbH
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    • 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
    • F04C18/126—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 radially from the rotor body extending elements, not necessarily co-operating with corresponding recesses in the other rotor, e.g. lobes, Roots type

Definitions

  • a rotary-piston machine has a housing receiving a pair of geometrically identical impellers each having a pair of identical lobes extending from a hub.
  • Each impeller is symmetrical about a first plane passing through its rotation axis and bisecting its lobes and about a second plane perpendicular to the first plane at the rotation axis.
  • Each lobe is formed with an outwardly circularly convex end surface defining an outer circle and the hub is formed with a pair of outwardly circularly convex lateral surfaces defining an inner circle concentric with the outer circle.
  • Each lobe further has a pair of lateral intermediate surfaces which blend into the lateral surfaces through first transition surfaces and with the end surfaces through second transition surfaces.
  • the intermediate surfaces are straight and parallel to the longitudinal axis of the impeller.
  • the second transition surfaces are circularly arcuate and centered on an intermediate circle equidistant between and concentric with the inner and outer circles.
  • the present invention relates to a rotary-piston machine. More particularly this invention concerns a rotary pump of the Roots or straight-vane type or a compressor.
  • a rotary pump of the lobar or straight-vane type has a pair of rigid impellers which are rotated in a housing in opposite senses about respective parallel rotation axes. As the impellers turn they form a pocket of fluid which is transferred from one side of the housing to another, from an inlet to an outlet, allowing such a machine to be used either as a vacuum pump or as a compressor, or even conceivably as a prime mover.
  • the impellers are usually symmetrical about two mutually perpendicular planes passing through their respective rotation axis, one of the planes bisecting the two lobes which extend from a central hub. On rotation the end of one impeller passes over the side of the other, while the opposite end sweeps the inside of the housing, and then vice versa so that leakage is possible as the result of the play between the impellers as they rotate and between these impellers and the housing.
  • Another object is the provision of such a machine wherein back leakage is reduced to a minimum while the machine is operable at a high rate of speed.
  • Yet another object is to provide an improved impeller for such a rotary-piston machine.
  • a rotary-piston machine of the abovedescribed general type whose impellers each have circularly arcuate end surfaces defining an outer or crown circle, borrowing terminology from the gear art.
  • the hub is also formed with two circularly arcuate lateral surfaces which lie to either side of the first plane of symmetry of the impeller which bisects the lobes, these lateral surfaces defining an inner or root circle.
  • Each lobe is further formed with a pair of intermediate surfaces that can be parallel to the first plane of symmetry.
  • Each intermediate surface blends into the neighboring end surface through an outwardly circularly convex (constant radius of curvature) transition region having a center of curvature lying near or on an intermediate circle concentric with the inner and outer circles and equispaced radially therebetween.
  • each transition surface blends into the neighboring lateral surface through two transition surfaces, one outwardly convex and the other inwardly convex, this latter surface having the same radius of curvature as the transition surface to the other side of the respective intermediate surface, with its center of curvature also lying on the intermediate circle.
  • the end surfaces subtend arcs of 45 and the transition surfaces bordering on these end surfaces each have their center of curvature on a diameter drawn through the respective rotation axis and forming an angle of 225 with the first (longitudinal) plane of symmetry. This diameter also marks the end of the end surface.
  • Such impellers are easily produced through the use of a milling machine and a pattern.
  • the shape is not unduly complicated so that conventional machining tools may be used to cut them.
  • the machine according to the present invention can be used as a compressor or vacuum pump. It comprises a housing 1 having a pair of lobes la and 1b each receiving an impeller 2. The housing further has an inlet 1c and an outlet 1d. Each impeller is mounted on a shaft 50 connected outside the housing 1 to a gear 5 which meshes with an identical gear 5 of the other impeller. A motor 5b serves to counterrotate the two impellers 2. Fluid is drawn in the inlet 1c and expelled from the outlet 1d.
  • each impeller has a pair of lobes 2a and a hub 2b, giving it a generally dumb-bell or peanut shape.
  • the particular shape of the impeller 2 is best described with reference to three terms borrowed from the spur-gear vocabulary: inner root or dedenum circle 8, outer crown or addendum circle 7, and intermediate or pitch circle 6. All of these circles 68 are concentric on the rotation axis A of the impeller 2, and the pitch circles of the impellers 2 osculates.
  • the impellers 2 are elongated transverse to their rotation axis and each has a longitudinal axis 3 passing through the axis A, and a transverse axis 4 orthogonal to the axis 3 and also passing through the axis A. These axes 3 and 4 form with the axis A respective mutually perpendicular symmetry planes P and P for the impeller 2.
  • FIG. 2A also shows how an arcuate surface 12' can replace the straight section 12, in which case an imaginary arc 12" parallel to the are 12 is spaced from it by a radial distance 18' equal to the radial distance 18.
  • each lobe 2a are circular arc segments 9 lying on the crown circle 7 and subtending an are 45 wide, this are being bisected by the plane P to form an angle of 225 between the axis 3 and the two lines 14 drawn to the axis A and marking the ends of the arcuate end 9. Thereafter the end 9 goes over into two circularly arcuate corners ll subtending arcs of 775 about a center 13 lying at the intersection of the respective line 14 and the pitch circle 6.
  • a line 18 drawn from the center 3 out at a right angle to the axis 3, and therefore parallel to the axis 4 defines the arc 11 with the end of line 13 on each side of end 9.
  • the edge configuration becomes that of two arcs 17 and 16 that join a circularly arcuate region 10 that lies on the root circle 8.
  • the arcuate section 17 has a center of curvature 19 and the section 16 a center 20 which all lie on a straight line extending through the point 13.
  • the point 20 lies outside the impeller 20 on the circle 6 and the point 19 lies inside the impeller.
  • the radius 21 of curvature of the arcuate region 16 is identical to the radium of curvature 18 of the region 11, which distance is equal to the radial spacing from circle 6 to each of circles 7 and 8.
  • each impeller 2 described above allows the two to operate with a minimum of noise or leakage.
  • FIGS. 3-8 describe their operation.
  • a rotary-piston machine having a housing receiving a pair of geometrically similar impellers rotatable in opposite senses about respective parallel rotation axes, each impeller being formed with a hub and a pair of diametrically opposite lobes extending from said hub, each impeller having a first axial plane of symmetry bisecting said lobes and a second axial plane of symmetry perpendicular to said first plane, the improvement wherein:
  • each lobe has a circular-arc segment end surface of constant radius of curvature defining an outer circle centered on the respective impeller rotation axis;
  • said hub has a pair of circular-arc-segment lateral surfaces of constant radius of curvature on opposite sides of said first plane and defining an inner circle concentric with and lying within said outer circle;
  • each lobe has a pair of mutually parallel rectilinear intermediate surfaces lying on opposite sides of said first plane between said inner and outer circles and parallel to said first axial plane of symmetry bisecting said lobes;
  • each lobe has a pair of first transition surfaces on opposite sides of said first plane and each lying between a respective intermediate surface and a respective lateral surface;
  • each lobe has a pair of outwardly circularly convex second transition surfaces of constant radius of curvature on opposite sides of said first plane and each lying between a respective intermediate surface and a respective end surface and each centered substantially on an intermediate circle concentric with and lying between said inner and outer circles, the intermediate circle of each impeller osculating the intermediate circle of the other impeller, each of said second transition surfaces having a center of curvature lying on said intermediate circle, each of said end surfaces subtending a circular arc of substantially 45, each of said first transition surfaces being formed of a pair of neighboring curved surfaces, one of each pair of curved surfaces being inwardly convex and adjoining a respective lateral surface, and the other of each pair of curved surfaces being outwardly convex and adjoining the respective intermediate surface, said one of each pair of curved surfaces having a radius of curvature similar to that of each second transition surface, and a center of curvature lying on said intermediate surface, the center of curvature of each of said second transition surfaces lying at the intersection

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US00228251A 1971-02-24 1972-02-22 Rotary-piston machine Expired - Lifetime US3817667A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712108714 DE2108714B2 (de) 1971-02-24 1971-02-24 Parallel- und aussenachsige rotationskolbenmaschine

Publications (1)

Publication Number Publication Date
US3817667A true US3817667A (en) 1974-06-18

Family

ID=5799665

Family Applications (1)

Application Number Title Priority Date Filing Date
US00228251A Expired - Lifetime US3817667A (en) 1971-02-24 1972-02-22 Rotary-piston machine

Country Status (7)

Country Link
US (1) US3817667A (de)
AT (1) AT314062B (de)
CH (1) CH537526A (de)
DE (1) DE2108714B2 (de)
FR (1) FR2127729A5 (de)
GB (1) GB1345107A (de)
IT (1) IT947817B (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4033708A (en) * 1974-08-28 1977-07-05 Calspan Corporation Rotary compressor
US4455132A (en) * 1982-02-23 1984-06-19 Fiat Auto S.P.A. Volumetric compressor of the roots type
US4940394A (en) * 1988-10-18 1990-07-10 Baker Hughes, Inc. Adjustable wearplates rotary pump
US5039289A (en) * 1983-11-07 1991-08-13 Wankel Gmbh Rotary piston blower having piston lobe portions shaped to avoid compression pockets
US5336069A (en) * 1993-03-15 1994-08-09 Ogura Clutch Co., Ltd. Rotary piston fluid pump
US6095781A (en) * 1997-09-11 2000-08-01 Viking Pump, Inc. Timed element, high pressure, industrial rotary lobe pump
WO2006015766A1 (de) * 2004-08-05 2006-02-16 Börger GmbH Drehkolbenpumpe mit einem pumpengehäuse und zwei zweiflügeligen drehkolben
US20070274853A1 (en) * 2003-08-20 2007-11-29 Renault S.A.S. Gear Tooth and External Gear Pump
US20080056927A1 (en) * 2006-09-05 2008-03-06 Herold & Co. Gmbh Pump
CN107061271A (zh) * 2017-03-08 2017-08-18 杭州电子科技大学 一种高真空容积泵宽头转子

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8503374A (nl) * 1984-12-07 1986-07-01 Naaktgeboren Maschf Rotterdam Pneumatische transportinrichting.
DE3519170A1 (de) * 1985-05-29 1986-12-04 Wankel Gmbh Aussenachsiges rotationskolbengeblaese
CN103486041B (zh) * 2013-10-14 2016-03-02 山东伯仲真空设备股份有限公司 罗茨泵转子

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US30157A (en) * 1860-09-25 -roots
US647951A (en) * 1898-10-17 1900-04-24 P H & F M Roots Company Rotary pump.
US704224A (en) * 1902-01-11 1902-07-08 P H & F M Roots Company Rotary pump.
US1361423A (en) * 1916-04-19 1920-12-07 Waterous Engine Works Company Rotary pump
US3089638A (en) * 1958-12-01 1963-05-14 Dresser Ind Impellers for fluid handling apparatus of the rotary positive displacement type
US3105634A (en) * 1960-12-27 1963-10-01 Polysius Gmbh Rotary piston for a roots blower
GB958143A (en) * 1960-07-16 1964-05-13 Wilhelm Glamann Improvements in or relating to displacement compressors
US3371856A (en) * 1966-03-24 1968-03-05 Fuller Co Modified cycloidal impeller

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2321696A (en) * 1940-02-06 1943-06-15 Imo Industri Ab Screw rotor
FR1105103A (fr) * 1953-09-21 1955-11-28 Saurer Ag Adolph Compresseur rotatif équipé de rotors à denture héliocoïdale
FR1170967A (fr) * 1957-04-08 1959-01-21 Expl Du Generateur A Piston Li Pompes et moteurs à engrenage
GB837128A (en) * 1957-07-18 1960-06-09 John Wilmott Marshall Rotary pumps and engines
DE1503553A1 (de) * 1965-03-20 1970-03-26 Wilhelm Klein Inhaber Otto Sch Drehkolbengeblaese,sogenannte Roots Geblaese

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US30157A (en) * 1860-09-25 -roots
US647951A (en) * 1898-10-17 1900-04-24 P H & F M Roots Company Rotary pump.
US704224A (en) * 1902-01-11 1902-07-08 P H & F M Roots Company Rotary pump.
US1361423A (en) * 1916-04-19 1920-12-07 Waterous Engine Works Company Rotary pump
US3089638A (en) * 1958-12-01 1963-05-14 Dresser Ind Impellers for fluid handling apparatus of the rotary positive displacement type
GB958143A (en) * 1960-07-16 1964-05-13 Wilhelm Glamann Improvements in or relating to displacement compressors
US3105634A (en) * 1960-12-27 1963-10-01 Polysius Gmbh Rotary piston for a roots blower
US3371856A (en) * 1966-03-24 1968-03-05 Fuller Co Modified cycloidal impeller

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4033708A (en) * 1974-08-28 1977-07-05 Calspan Corporation Rotary compressor
US4455132A (en) * 1982-02-23 1984-06-19 Fiat Auto S.P.A. Volumetric compressor of the roots type
US5039289A (en) * 1983-11-07 1991-08-13 Wankel Gmbh Rotary piston blower having piston lobe portions shaped to avoid compression pockets
US4940394A (en) * 1988-10-18 1990-07-10 Baker Hughes, Inc. Adjustable wearplates rotary pump
US5336069A (en) * 1993-03-15 1994-08-09 Ogura Clutch Co., Ltd. Rotary piston fluid pump
US6095781A (en) * 1997-09-11 2000-08-01 Viking Pump, Inc. Timed element, high pressure, industrial rotary lobe pump
US8109748B2 (en) * 2003-08-20 2012-02-07 Renault S.A.S. Gear tooth and external gear pump
US20070274853A1 (en) * 2003-08-20 2007-11-29 Renault S.A.S. Gear Tooth and External Gear Pump
WO2006015766A1 (de) * 2004-08-05 2006-02-16 Börger GmbH Drehkolbenpumpe mit einem pumpengehäuse und zwei zweiflügeligen drehkolben
US20090123319A1 (en) * 2004-08-05 2009-05-14 Boerger Alois "rotary piston pump comprising a pump housing and two double bladed rotary pistons"
US7766635B2 (en) * 2006-09-05 2010-08-03 Herold & Co. Gmbh Rotary pump having sinusoidal sealing lines
US20080056927A1 (en) * 2006-09-05 2008-03-06 Herold & Co. Gmbh Pump
CN107061271A (zh) * 2017-03-08 2017-08-18 杭州电子科技大学 一种高真空容积泵宽头转子

Also Published As

Publication number Publication date
FR2127729A5 (de) 1972-10-13
DE2108714A1 (de) 1972-09-07
CH537526A (de) 1973-05-31
AT314062B (de) 1974-03-25
GB1345107A (en) 1974-01-30
IT947817B (it) 1973-05-30
DE2108714B2 (de) 1973-05-30

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