US3667874A - Two-stage compressor having interengaging rotary members - Google Patents

Two-stage compressor having interengaging rotary members Download PDF

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US3667874A
US3667874A US58009A US3667874DA US3667874A US 3667874 A US3667874 A US 3667874A US 58009 A US58009 A US 58009A US 3667874D A US3667874D A US 3667874DA US 3667874 A US3667874 A US 3667874A
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stage
chamber
partition
impellers
working chamber
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US58009A
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Roger C Weatherston
George R Duryea
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Edison International Inc
Calspan Corp
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Calspan Corp
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Assigned to STUDEBAKER-WORTHINGTON, INC. reassignment STUDEBAKER-WORTHINGTON, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: WORTHINGTON COMPRESSORS, INC. A CORP. OF DE
Assigned to EDISON INTERNATONAL, INC. reassignment EDISON INTERNATONAL, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: STUDEBAKER-WORTHINGTON, INC., A CORP. OF DE
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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
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/02—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids specially adapted for several pumps connected in series or in parallel
    • 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
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/001—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids of similar working principle
    • 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
    • F01C1/00—Rotary-piston machines or engines
    • F01C1/08—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing
    • F01C1/12—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type
    • F01C1/126—Rotary-piston machines or engines 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 elements extending radially from the rotor body not necessarily cooperating with corresponding recesses in the other rotor, e.g. lobes, Roots type

Definitions

  • a two-staged Roots type compressor having a housing separated into two compartments by a partition, each compartment containing a working chamber having rotary mating impellers therein, inlets to each chamber and outlets from each chamber, passages in the partition communicating the outlet of one chamber with the inlet of the other chamber, a valved passage in the partition communicating the inlets of each chamber, the impellers of each chamber being mounted on common shafts.
  • Roots type compressors perform satisfactorily at compression ratios below two; however, as the compression ratio increases the efficiency of the compressor decreases significantly. Attempts to increase the efficiency of Roots type compressors by staging two compressors in series are known. Up to a compression ratio of about 3.5 the two staged Roots type compressors performance is good, however, since multiple housings, timing gears, drive shafts, bearings, external piping and seals are required, the manufacturing costs are extremely high. In addition to being costly the known two stage Roots type compressors are complex and bulky for their capacity.
  • the present invention provides a two stage Roots type compressor structure conduits or piping between the stages wherein all of the connections between stages are internal thereby avoiding the necessity of external conduits or piping between the stages.
  • the apparatus according to the invention also incorporates valving structure which permits, in a simple and efficient manner, the regulation of the flow rate through the compressor.
  • the present invention provides a two stage Roots type compressor having: a first stage housing, defining an interior working chamber, a second stage housing defining an interior working chamber, first stage inlets and outlets communicating with the working chamber of said first stage housing, second stage inlets and outlets communicating with the working chamber of said second stage housing.
  • FIG. 1 is a cross-sectional view of the lower first stage of the compressor according to the present invention and is taken along line 1-1 of FIG. 2;
  • FIG. 2 is a longitudinal sectional view along line 22 of FIG. 1;
  • the two stage Roots type compressor according to the invention is generally depicted by the numeral 10 and comprises a generally annular first or low pressure stage housing 12 which may be oblong in section as shown.
  • the housing is flanged at 13.
  • a curved interior wall 14 divides the first stage housing into two sections; an inner working chamber 16 and a surrounding annular discharge chamber 18.
  • Wall 14 joins Wall 12 at the curved section 20 which defines an inlet passage thereat which provides communication between an inlet port 22 and the working chamber 16.
  • the opposite portion of wall 14 is open at 24 which provides communication between working chamber 16 and annular discharge chamber 18.
  • Wall 14 may have one or more bypass ports or slots 26 therein for a purpose to be discussed hereinbelow.
  • Roots type impeller elements 28 and 30 are mounted on shafts 32 and 34 for rotation in chamber 16. As shown for illustrative purposes only, each impeller has three lobes.
  • Partition 38 has a pair of through ports 40 and 42 which communicate with annular discharge chamber 18. Between ports 40 and 42 partition 38 also contains a bypass port 44 which communicates with the first stage inlet passage 20.
  • a valve member illustrated schematically in FIG. 2 is adapted to seat on and close communication through port 44.
  • this valve may comprise a frustoconical head 46, a forward piston portion 48, guides 50 and a stem 52, which may pass through end plate 36 for actuation by a suitable actuator.
  • a second or high pressure stage housing 54 sealingly abuts partition 38.
  • Housing 54 is similar in exterior configuration to housing 12 and comprises an interior Working chamber 56, curved ledges 58 between chamber 56 and casing 54 defining a discharge slot 60 leading to an arcuate discharge region 62, curved lips 64 between chamber 56 and casing 54 opposite ledges 58 which define a second stage inlet slot 66 leading to an arcuate second stage inlet region 68.
  • Ports 40, 42 and 44 in partition 38 are in communication with the second stage inlet re gion 68.
  • An outlet port 70 is in communication with the outlet region 62.
  • Ledge 58 contains one or more bypass ports or slots 72 similar to slots 26 of the first stage.
  • a pair of second stage Roots type impeller elements 74 and 76 are mounted on shafts 32 and 34 for rotation in chamber 56. Impeller 74 is located on the same shaft as impeller 30 and impeller 76 is located on the same shaft as impeller 28 and all contain three lobes as illustrated. For a purpose to be discussed hereinbelow, it is important to note that each one of the impellers on each of the shafts is one half cycle out of phase with the other impeller on the same shaft. Thus, impeller 28 is one half cycle out of phase with impeller 74 and impeller 30 is substantially one half cycle out of phase with impeller 76. With three lobes as illustrated the impellers in each stage are 60 degrees out of phase.
  • An end sealing plate 78 abuts and seals against one end flange 80 of housing 54 and thereby closes one end of chamber 56 and regions 62 and 68, the other ends of which are closed by partition 38.
  • the structure is joined and secured by suitable fastening means illustrated at 81.
  • a single pair of conventional driving and timing gears 82 and 84 are located on shafts 32 and 34 for driving impellers 28, 30, 74 and 76.
  • Conventional end bearings are provided at 86, '88, 90 and 92.
  • inlet gas is drawn in through port 22, passage 20 into first stage working chamber 16.
  • the gas is compressed by the action of impellers 28 and 30 and is discharged through opening 24 to annular discharge chamber 18, thence through ports 40 and 42 in partition 38 to the inlet region 68 of the second stage casing; 54'.
  • region 68 the gas is drawn into the second stage Working chamber 56 through opening 66 where it under goes further compression by the action of impellers 74 and 76 and is discharged through slot 6-0 to outlet region 62 to outlet port 70 to a point of use.
  • valve 46 may be actuated to permit turndown of the compressor by causing a variable portion of the gas entering second stage inlet region 68 to be returned via port 44 to the first stage inlet opening 20.
  • Valve 46 may be operated in response to the speed of the impellers to permit an automatic capacity turndown.
  • any suitable type of actuation could be employed.
  • the impellers of the first stage are substantially one half cycle (60) out of phase with the impellers of the second stage.
  • the vector relations of loads from the first and second stage impellers are at a 60 angle with respect to each other and as a consequence the maximum load is less than for the case where each impeller is in phase.
  • the variation in torsional loading on each shaft is reduced and the torque requirement in the driving and timing gears is made more uniform.
  • the ideal phase difference would be 120/2 or 60 degrees.
  • the ideal phase difierence would be 180/2 or 90' degrees.
  • bypass ports 26 and 72 are to smooth out pulsations, reduce noise and augment the shaft work as disclosed in copending application Ser. No. 742,890 filed July 5, 1968 for Gear Compressors and Expanders, now Pat. No. 3,531,227, and assigned to the assignee of the present invention.
  • a two-stage Roots type compressor comprising;

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)

Abstract

A TWO-STAGED ROOTS TYPE COMPRESSOR HAVING A HOUSING SEPARATED INTO TWO COMPARTMENTS BY A PARTITION, EACH COMPARTMENT CONTAINING A WORKING CHAMBER HAVING ROTARY MATING IMPELLERS THEREIN, INLETS TO EACH MEMBER AND OUTLETS FROM EACH CHAMBER, PASSAGES IN THE PARTITION COMMUNICATING THE OUTLET OF ONE ANOTHER WITH THE INLET OF THE OTHER CHAMBER, VALVED PASSAGE IN THE PARTITION COMMUNICATING THE INLETS OF EACH CHAMBER, THE IMPELLERS OF EACH CHAMBER BEING MOUNTED ON COMMON SHAFTS.

Description

June 1972 R. c. WEATHERSTON ETAL 3,557,374
TWO-STAGE COMPRESSOR HAVING INTERENGAGING ROTARY MEMBERS 2 Sheets-Sheet 1 Filed July 24, 1970 INVENTORs GEORGE R. DURYEA ROGER C. WEATHERSTON ATTORNEY June 6, 1972 R. c. WEATHERSTON ETAL ,8
TWO-STAGE COMPRESSOR HAVING INTERENGAGING RQTARY MEMBERS Filed July 24, 1970 2 Sheets-Sheet 2 INVENTORS GEORGE R. DURYEA ROGER C. WEATHERSTON BY Q4 ATTORNEY United States Patent 3,667,874 TWO-STAGE COMPRESSOR HAVING INTER- ENGAGING ROTARY MEMBERS Roger C. Weatherston, Williamsville, and George R.
Duryea, Bulialo, N.Y., assignors to Cornell Aeronautical Laboratory, Inc., Bufialo, N.Y.
Filed July 24, 1970, Ser. No. 58,009 Int. Cl. F01c 1/18, 1/30 US. Cl. 418-9 3 Claims ABSTRACT OF THE DISCLOSURE A two-staged Roots type compressor having a housing separated into two compartments by a partition, each compartment containing a working chamber having rotary mating impellers therein, inlets to each chamber and outlets from each chamber, passages in the partition communicating the outlet of one chamber with the inlet of the other chamber, a valved passage in the partition communicating the inlets of each chamber, the impellers of each chamber being mounted on common shafts.
BACKGROUND OF THE INVENTION Roots type compressors perform satisfactorily at compression ratios below two; however, as the compression ratio increases the efficiency of the compressor decreases significantly. Attempts to increase the efficiency of Roots type compressors by staging two compressors in series are known. Up to a compression ratio of about 3.5 the two staged Roots type compressors performance is good, however, since multiple housings, timing gears, drive shafts, bearings, external piping and seals are required, the manufacturing costs are extremely high. In addition to being costly the known two stage Roots type compressors are complex and bulky for their capacity.
SUMMARY OF THE INVENTION The foregoing disadvantages of prior devices are overcome according to the present invention which provides a two staged Roots type compressor having the same number of drive shafts, bearings, timing gears that are normally incorporated in a single stage device.
Additionally, the present invention provides a two stage Roots type compressor structure conduits or piping between the stages wherein all of the connections between stages are internal thereby avoiding the necessity of external conduits or piping between the stages.
The apparatus according to the invention also incorporates valving structure which permits, in a simple and efficient manner, the regulation of the flow rate through the compressor.
Basically, the present invention provides a two stage Roots type compressor having: a first stage housing, defining an interior working chamber, a second stage housing defining an interior working chamber, first stage inlets and outlets communicating with the working chamber of said first stage housing, second stage inlets and outlets communicating with the working chamber of said second stage housing.
BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the present invention reference should be had to the following detailed description of the same, taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a cross-sectional view of the lower first stage of the compressor according to the present invention and is taken along line 1-1 of FIG. 2;
FIG. 2 is a longitudinal sectional view along line 22 of FIG. 1; and
3,667,874 Patented June 6, 1972 "ice DESCRIPTION OF 'THE PREFERRED EMBODIMENTS Referring now to the drawings, the two stage Roots type compressor according to the invention is generally depicted by the numeral 10 and comprises a generally annular first or low pressure stage housing 12 which may be oblong in section as shown. The housing is flanged at 13. A curved interior wall 14 divides the first stage housing into two sections; an inner working chamber 16 and a surrounding annular discharge chamber 18. Wall 14 joins Wall 12 at the curved section 20 which defines an inlet passage thereat which provides communication between an inlet port 22 and the working chamber 16. The opposite portion of wall 14 is open at 24 which provides communication between working chamber 16 and annular discharge chamber 18. Wall 14 may have one or more bypass ports or slots 26 therein for a purpose to be discussed hereinbelow.
A pair of coacting multilobed Roots type impeller elements 28 and 30 are mounted on shafts 32 and 34 for rotation in chamber 16. As shown for illustrative purposes only, each impeller has three lobes.
The open ends of chambers 16 and 18 are sealingly closed by an end plate 36 and an interstage partition 38. Conventional sealing rings (not illustrated) may be employed. Partition 38 has a pair of through ports 40 and 42 which communicate with annular discharge chamber 18. Between ports 40 and 42 partition 38 also contains a bypass port 44 which communicates with the first stage inlet passage 20.
A valve member, illustrated schematically in FIG. 2 is adapted to seat on and close communication through port 44. As shown this valve may comprise a frustoconical head 46, a forward piston portion 48, guides 50 and a stem 52, which may pass through end plate 36 for actuation by a suitable actuator.
A second or high pressure stage housing 54 sealingly abuts partition 38. Housing 54 is similar in exterior configuration to housing 12 and comprises an interior Working chamber 56, curved ledges 58 between chamber 56 and casing 54 defining a discharge slot 60 leading to an arcuate discharge region 62, curved lips 64 between chamber 56 and casing 54 opposite ledges 58 which define a second stage inlet slot 66 leading to an arcuate second stage inlet region 68. Ports 40, 42 and 44 in partition 38 are in communication with the second stage inlet re gion 68. An outlet port 70 is in communication with the outlet region 62. Ledge 58 contains one or more bypass ports or slots 72 similar to slots 26 of the first stage.
A pair of second stage Roots type impeller elements 74 and 76 are mounted on shafts 32 and 34 for rotation in chamber 56. Impeller 74 is located on the same shaft as impeller 30 and impeller 76 is located on the same shaft as impeller 28 and all contain three lobes as illustrated. For a purpose to be discussed hereinbelow, it is important to note that each one of the impellers on each of the shafts is one half cycle out of phase with the other impeller on the same shaft. Thus, impeller 28 is one half cycle out of phase with impeller 74 and impeller 30 is substantially one half cycle out of phase with impeller 76. With three lobes as illustrated the impellers in each stage are 60 degrees out of phase.
An end sealing plate 78 abuts and seals against one end flange 80 of housing 54 and thereby closes one end of chamber 56 and regions 62 and 68, the other ends of which are closed by partition 38. The structure is joined and secured by suitable fastening means illustrated at 81.
A single pair of conventional driving and timing gears 82 and 84 are located on shafts 32 and 34 for driving impellers 28, 30, 74 and 76. Conventional end bearings are provided at 86, '88, 90 and 92.
In operation inlet gas is drawn in through port 22, passage 20 into first stage working chamber 16. The gas is compressed by the action of impellers 28 and 30 and is discharged through opening 24 to annular discharge chamber 18, thence through ports 40 and 42 in partition 38 to the inlet region 68 of the second stage casing; 54'. From region 68 the gas is drawn into the second stage Working chamber 56 through opening 66 where it under goes further compression by the action of impellers 74 and 76 and is discharged through slot 6-0 to outlet region 62 to outlet port 70 to a point of use.
If it is desirable to reduce or otherwise regulate the flow capacity valve 46 may be actuated to permit turndown of the compressor by causing a variable portion of the gas entering second stage inlet region 68 to be returned via port 44 to the first stage inlet opening 20. Valve 46 may be operated in response to the speed of the impellers to permit an automatic capacity turndown. Alternatively, any suitable type of actuation could be employed.
As noted earlier, the impellers of the first stage are substantially one half cycle (60) out of phase with the impellers of the second stage. Thus, the vector relations of loads from the first and second stage impellers are at a 60 angle with respect to each other and as a consequence the maximum load is less than for the case where each impeller is in phase. In addition the variation in torsional loading on each shaft is reduced and the torque requirement in the driving and timing gears is made more uniform. With three lobe impellers as illustrated the ideal phase difference would be 120/2 or 60 degrees. With two lobes the ideal phase difierence would be 180/2 or 90' degrees.
The purpose of bypass ports 26 and 72 is to smooth out pulsations, reduce noise and augment the shaft work as disclosed in copending application Ser. No. 742,890 filed July 5, 1968 for Gear Compressors and Expanders, now Pat. No. 3,531,227, and assigned to the assignee of the present invention.
Although a preferred embodiment of the present invention has been described, changes will occur to those skilled in the art; therefore, it is intended that the scope of the present invention is to be limited only by the scope of the appended claims.
We claim:
1. A two-stage Roots type compressor, comprising;
(a) a first stage housing defining an interior working chamber,
(b) a second stage housing adjacent said first stage housing defining an interior working chamber,
(c) a thin walled partition intermediate said first and second stage housings,
(d) first stage inlets and outlets communicating with the working chamber of said first stage housing,
(e) second stage inlet and outlets communicating with the working chamber of said second stage housing,
(f) ports in said partition communicating said first stage outlet with said second stage inlet,
(g) an annular chamber surrounding said first stage working chamber, one end of which communicates with said first stage outlet, the other end of which communicates with said ports in said partition,
(11) a pair of spaced rotating shafts passing through each of said working chambers,
(i) mating Roots type impellers mounted on said shafts in said first stage working chamber, and
(j) mating Roots type impellers mounted on said shafts in said second stage working chamber.
2. The compressor according to claim 1, further comprising;
(k) a turndown port in said partition communicating said second stage inlet with said first stage inlet, and
(l) a valve coacting with said turndown port.
3. The compressor according to claim 2, wherein;
(m) the impellers common to each of said shafts are substantially one half cycle out of phase.
References Cited UNITED STATES PATENTS 3,150,593 9/1964 Funk et al 418-9 X 2,324,116 7/1943 Sivertsen 4189 X 1,531,607 371925 Green 418-9 2,489,887 ll/ 1949 Houghton 418-86 713,443 11/ 1902 Jewell 418-206.
FOREIGN PATENTS 2,402 9/ 1857 Great Britain 418-9 CARLTON R. CROYLE, Primary Examiner R. E. GLUCK, Assistant Examiner
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Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3940925A (en) * 1974-01-28 1976-03-02 Kelley Arthur P Rotary internal combustion engine
US4012903A (en) * 1972-07-24 1977-03-22 Riedl Frank E Internal combustion engine
US4044562A (en) * 1974-05-02 1977-08-30 Will Clarke England Multirotary energy conversion valve
US4215977A (en) * 1977-11-14 1980-08-05 Calspan Corporation Pulse-free blower
US4502283A (en) * 1982-09-24 1985-03-05 General Motors Corporation Turbocharged engine driven positive displacement blower having a bypass passage
US4556373A (en) * 1984-09-04 1985-12-03 Eaton Corporation Supercharger carryback pulsation damping means
US4564346A (en) * 1984-09-04 1986-01-14 Eaton Corporation Supercharger with hourglass outlet port
US4564345A (en) * 1984-09-04 1986-01-14 Eaton Corporation Supercharger with reduced noise
US4569646A (en) * 1984-09-04 1986-02-11 Eaton Corporation Supercharger carry-over venting means
EP0174171A2 (en) * 1984-09-04 1986-03-12 Eaton Corporation Supercharger with reduced noise
EP0176270A2 (en) * 1984-09-20 1986-04-02 Eaton Corporation Supercharger with reduced noise and improved efficiency
US4643655A (en) * 1985-12-05 1987-02-17 Eaton Corporation Backflow passage for rotary positive displacement blower
US4652223A (en) * 1984-04-13 1987-03-24 Aerzener Maschinenfabrik Gmbh Roots compressor for compressing of gaseous media
EP0272767A2 (en) * 1986-12-18 1988-06-29 Unozawa-Gumi Iron Works, Ltd. Multi-section roots vacuum pump of reverse flow cooling type with internal flow division arrangement
US4768934A (en) * 1985-11-18 1988-09-06 Eaton Corporation Port arrangement for rotary positive displacement blower
US4781541A (en) * 1986-06-20 1988-11-01 Wankel Gmbh External axial rotary piston blower with noise suppressing transfer ports
EP0359423A2 (en) * 1988-09-05 1990-03-21 Unozawa-Gumi Iron Works, Ltd. Multi-section roots vacuum pump of reverse flow cooling type
US5846062A (en) * 1996-06-03 1998-12-08 Ebara Corporation Two stage screw type vacuum pump with motor in-between the stages
US6527530B2 (en) * 2000-04-13 2003-03-04 Robert Bosch Gmbh Gear-wheel pump, in particular for a high-pressure fuel pump
WO2005019653A1 (en) * 2003-08-18 2005-03-03 The Boc Group Plc Low pulsation booster pump
US20050089424A1 (en) * 2003-10-23 2005-04-28 Ming-Hsin Liu Multi-stage vacuum pump
US20070104587A1 (en) * 2003-10-17 2007-05-10 Takeshi Kawamura Evacuation apparatus
US7226280B1 (en) * 2006-06-01 2007-06-05 Anlet Co., Ltd. Roots vacuum pump
US20110058974A1 (en) * 2005-05-23 2011-03-10 Eaton Corporation Optimized helix angle rotors for roots-style supercharger
US20130146035A1 (en) * 2011-12-09 2013-06-13 Eaton Corporation Air supply system with two-stage roots blower
DE102009012368B4 (en) * 2008-03-14 2015-08-20 GM Global Technology Operations LLC (n. d. Ges. d. Staates Delaware) Loader with outlet webs for supporting rotor sealing strips
US20170254330A1 (en) * 2014-09-04 2017-09-07 Scoprega S.P.A. Volumetric compressor
US9822781B2 (en) 2005-05-23 2017-11-21 Eaton Corporation Optimized helix angle rotors for roots-style supercharger
US10436197B2 (en) 2005-05-23 2019-10-08 Eaton Intelligent Power Limited Optimized helix angle rotors for roots-style supercharger
US11286932B2 (en) 2005-05-23 2022-03-29 Eaton Intelligent Power Limited Optimized helix angle rotors for roots-style supercharger
US11578722B2 (en) 2017-01-20 2023-02-14 Edwards Limited Multi-stage vacuum booster pump coupling

Cited By (47)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012903A (en) * 1972-07-24 1977-03-22 Riedl Frank E Internal combustion engine
US3940925A (en) * 1974-01-28 1976-03-02 Kelley Arthur P Rotary internal combustion engine
US4044562A (en) * 1974-05-02 1977-08-30 Will Clarke England Multirotary energy conversion valve
US4108198A (en) * 1974-05-02 1978-08-22 Will Clarke England Multirotary energy conversion valve
US4215977A (en) * 1977-11-14 1980-08-05 Calspan Corporation Pulse-free blower
US4502283A (en) * 1982-09-24 1985-03-05 General Motors Corporation Turbocharged engine driven positive displacement blower having a bypass passage
US4652223A (en) * 1984-04-13 1987-03-24 Aerzener Maschinenfabrik Gmbh Roots compressor for compressing of gaseous media
EP0174171A2 (en) * 1984-09-04 1986-03-12 Eaton Corporation Supercharger with reduced noise
US4564345A (en) * 1984-09-04 1986-01-14 Eaton Corporation Supercharger with reduced noise
US4569646A (en) * 1984-09-04 1986-02-11 Eaton Corporation Supercharger carry-over venting means
EP0174171A3 (en) * 1984-09-04 1987-03-18 Eaton Corporation Supercharger with reduced noise
US4564346A (en) * 1984-09-04 1986-01-14 Eaton Corporation Supercharger with hourglass outlet port
US4556373A (en) * 1984-09-04 1985-12-03 Eaton Corporation Supercharger carryback pulsation damping means
EP0176270A2 (en) * 1984-09-20 1986-04-02 Eaton Corporation Supercharger with reduced noise and improved efficiency
US4609335A (en) * 1984-09-20 1986-09-02 Eaton Corporation Supercharger with reduced noise and improved efficiency
EP0176270A3 (en) * 1984-09-20 1987-03-11 Eaton Corporation Supercharger with reduced noise and improved efficiency
US4768934A (en) * 1985-11-18 1988-09-06 Eaton Corporation Port arrangement for rotary positive displacement blower
US4643655A (en) * 1985-12-05 1987-02-17 Eaton Corporation Backflow passage for rotary positive displacement blower
EP0246382A2 (en) * 1985-12-05 1987-11-25 Eaton Corporation Backflow passage for rotary blower of the Roots-type
EP0246382A3 (en) * 1985-12-05 1988-01-07 Eaton Corporation Backflow passage for rotary blower of the roots-type
US4781541A (en) * 1986-06-20 1988-11-01 Wankel Gmbh External axial rotary piston blower with noise suppressing transfer ports
EP0272767A3 (en) * 1986-12-18 1988-09-21 Unozawa-Gumi Iron Works, Ltd. Multi-section roots vacuum pump of reverse flow cooling type with internal flow division arrangement
EP0272767A2 (en) * 1986-12-18 1988-06-29 Unozawa-Gumi Iron Works, Ltd. Multi-section roots vacuum pump of reverse flow cooling type with internal flow division arrangement
US4789314A (en) * 1986-12-18 1988-12-06 Unozawa-Gumi Iron Works, Ltd. Multi-section roots vacuum pump of reverse flow cooling type with internal flow division arrangement
EP0359423A2 (en) * 1988-09-05 1990-03-21 Unozawa-Gumi Iron Works, Ltd. Multi-section roots vacuum pump of reverse flow cooling type
EP0359423A3 (en) * 1988-09-05 1990-06-27 Unozawa-Gumi Iron Works, Ltd. Multi-section roots vacuum pump of reverse flow cooling type
US4995796A (en) * 1988-09-05 1991-02-26 Unozawa - Gumi Iron Works, Ltd. Multi-section roots vacuum pump of reverse flow cooling type
US5846062A (en) * 1996-06-03 1998-12-08 Ebara Corporation Two stage screw type vacuum pump with motor in-between the stages
US6527530B2 (en) * 2000-04-13 2003-03-04 Robert Bosch Gmbh Gear-wheel pump, in particular for a high-pressure fuel pump
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