US3756753A - Two stage screw rotor machines - Google Patents

Two stage screw rotor machines Download PDF

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Publication number
US3756753A
US3756753A US00162244A US3756753DA US3756753A US 3756753 A US3756753 A US 3756753A US 00162244 A US00162244 A US 00162244A US 3756753D A US3756753D A US 3756753DA US 3756753 A US3756753 A US 3756753A
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United States
Prior art keywords
stage
machine
capacity
movable valve
high pressure
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Expired - Lifetime
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US00162244A
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English (en)
Inventor
W Persson
L Benedictus
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.)
Svenska Rotor Maskiner AB
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Svenska Rotor Maskiner AB
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Publication date
Application filed by Svenska Rotor Maskiner AB filed Critical Svenska Rotor Maskiner AB
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Publication of US3756753A publication Critical patent/US3756753A/en
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    • 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
    • F01C20/00—Control of, monitoring of, or safety arrangements for, machines or engines
    • F01C20/10—Control of, monitoring of, or safety arrangements for, machines or engines characterised by changing the positions of the inlet or outlet openings with respect to the working chamber
    • F01C20/12—Control of, monitoring of, or safety arrangements for, machines or engines characterised by changing the positions of the inlet or outlet openings with respect to the working chamber using sliding valves
    • F01C20/125—Control of, monitoring of, or safety arrangements for, machines or engines characterised by changing the positions of the inlet or outlet openings with respect to the working chamber using sliding valves with sliding valves controlled by the use of fluid other than the working fluid
    • 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

Definitions

  • ABSTRACT A two-stage screw rotor compressor in which each stage is provided with an adjustable slide valve for varying the volumetric capacity of the stage which makes it possible to vary the capacity of the compressor within wide limits while maintaininga higher efficiency within the whole operating range than in hitherto known compressors of this type.
  • the two valves are interconnected to move in unison. 7
  • the invention relates to screw rotor machines having at least two stages for compressing or expanding an elastic working fluid and being of the type in which each stage includes a pair of intermeshing screw rotors.
  • the first or low pressure stage determines the volumetric capacity of the compressor.
  • the compressor is designed and the built-in pressure ratios of the two stages are chosen such that at full load the compressor delivers a desired gas quantity at a desired final pressure and at a satisfactory efficiency.
  • the capacity of the compressor must be variable.
  • One way to obtain a reduction of the capacity is to reduce the speed of the compressor.
  • the unfavourable effect of the internal leakage of the stages upon the volumetric efficiency is resulting in a reduction of the overall efficiency of the compressor.
  • the compressor is driven by an induction motor a change speed gearing must be incorporated in the plant involving increased costs and space demands. Therefore, capacity control by speed variation is in most cases not recommendable.
  • US. Pat. No. 3,314,597 discloses a screw rotor compressor of the single stagetype the capacity of which is variable by means of an axially movable slide valve member.
  • this compressor the built-in pressure ratio can be kept at a suitable high level also at partial capacity and the compressor can be adjusted down to very low capacities with a fairly high efficiency.
  • Two-stage screw rotor compressors are for several reasons normally designed such that the built-in pressure ratios of the two stages are substantially equal. For instance, if the total pressure ratio is 9:1 each stage has a built-in pressure ratio of about 3:1 and, starting from atmospheric pressure, the intermediate pressure will amount to about 3 kp/cm at full load. This involves that the second stage need only have a volumetric capacity of about one-third of the volumetric capacity of the first stage in order to' be capable of absorbing the gas mass delivered by the first stage at a pressure of 3 kp/cm.
  • One object of the invention is to provide a multistage screw rotor machine the capacity of which may be varied within wide limits and in which the efficiency within the whole operating range is higher than in hitherto known machines of this type.
  • the machine according to the invention is characterized in that each stage is provided with adjustable valve means for varying the volumetric capacity of the stage.
  • the movable valve members of the valve means are interconnected to move in unison.
  • the volumetric capacities of the first and second stages can be reduced concurrently in such a manner that the intermediate pressureis maintained substantially constant. Therefore, in a certain position of the valve member of the first stage the capacity of this stage is substantially zero as explained above. In a corresponding manner the capacity of the second stage can also be brought down to substantially zero. The compressor will then run at full speed at zero capacity. This is highly desirable for instance in refrigerating plants and compressed air systems in which the gas consumption may vary from zero to a maximum value.
  • two stages are arranged in side-by-side relationship, the rotor pairs being drivingly interconnected by transmission means at one end of the machine while actuating means for the valve members are provided at the other end thereof.
  • the high pressure port of the low pressure stage and the low pressure port of the high pressure stage are located at the same end of the machine as the transmission means and are in communication with each other through a passage the valve members may be interconnected by means of an inextensible flexible member guided by idler pulleys and passing through said passage, one of the valve members being Pat. application Ser. No.
  • each rotor pair consists of a male rotor and a female rotor.
  • numeral 10 designates the intermediate or barrel member of the compressor casing which further includes end wall members 12 and 14.
  • a low pressure working space 16 and a high pressure working space 18 disposed side-by-side and each working space is in known manner composed of two intersecting bores with parallel axes.
  • the end wall member 12 (to the left in FIG. 1) encloses an inlet chamber 20 and an outlet chamber 22.
  • the inlet chamber 20 communicates with the low pressure working space 16 through a low pressure port 24 while the outlet chamber communicates with the high pressure working space 18 through a high pressure port 26
  • a transfer chamber 28 is provided in end wall member 14 and communicates with the low pressure working space 16 through an outlet port 30 and with the high pressure working space 18 through an inlet port 32.
  • the outlet port 30 forms the high pressure port of the first or low pressure stage of the compressor while the inlet port 32 forms the low pressure port of the second or high pressure stage thereof.
  • a transmission housing 34 enclosing a drive gear 36 and two driven gears 38 and 40 the pitch circles being indicated by chain-dotted lines in FIG. 3.
  • the drive gear 36 is carried by a drive shaft 42 joumalled in and projecting through the housing 34 and connectable to a drive motor.
  • the driven gear 38 is secured to the shaft 44 of the male rotor of the first stage and the driven gear 40 is secured to the shaft 46 of the male rotor of the second stage of the compressor.
  • the rotors have been omitted in the Figures.
  • the rotors of the low pressure stage are joumalled in combined radial and thrust bearings in end wall member 14 and in radial bearings in end wall member 12.
  • the rotors of the high pressure stage are joumalled in combined radial and thrust bearings in end wall member 12 and in radial bearings in end wall member 14. Since the bearings are located above and below the plane of FIG. 1 they are not visible in this Fig.
  • Each stage is provided with an axially movable slide valve member of the type disclosed in US. Pat. No. 3,314,597. The function of such a valve member is described in detail in said specification. By moving the valve member from one end position to the other the volumetric capacity of each stage can be varied between a maximum and a minimum value.
  • valve member 48 of the high pressure stage is shown in its position for maximum capacity and located in an axially extending recess 50 in the wall of the working space 18.
  • An insert 52 in the end wall member 12 forms an extension of the recess 50 so that the valve member can be moved out into the outlet chamber 22 to its end position for minimum capacity.
  • a groove 54 which communicates with an oil supply opening 56.
  • plates 58 which sealingly engage the groove 54.
  • the valve member is further provided with two transverse bores 60 in communication with the groove 56. Passages 62 at the bottom of each bore 60 form nozzle openings for injecting oil into the working space for cooling, sealing and lubricating purposes as known per se.
  • valve member 64 of the low pressure stage is of the same design as valve member 48 and need not therefore be described.
  • valve members 48 and 64 are interconnected by an inextensible flexible member 66 such as a chain which is guided by two idler pulleys 68 and passes through the transfer chamber 28 in the end wall member 14.
  • the valve members are biassed by the fluid pressure towards their maximum capacity positions shown in FIG. 1 and the length of the flexible member 66 is adjusted such that in this condition the flexible member is free from slackness.
  • valve member 48 of the high pressure stage To the high pressure end of the valve member 48 of the high pressure stage is secured the piston rod 70 of a servo motor 72 of the piston and cylinder type secured to the outside of the end wall member 12.
  • a typical servo motor 72 is shown in US. Pat. No. 3,432,089 (especially FIG. 3), assigned to the same assignee as the present application.
  • a compression spring 74 is inserted between the valve member 48 of the high pressure stage and a bracket 78 provided in thetransfer chamber 28 in-the end wallmember .14. When the compressor plant is stopped this spring moves the valve members 48 and 64 to their minimum capacity positions thereby reducing the torque and power required to re-start the plant.
  • the invention is not limited to the preferred embodiment shown and described but may be applied to all types of multistage screw rotor machines.
  • each stage includes a pair of intermeshing screw rotors
  • each stage comprises adjustable valve means for varying the volumetric capacity of the respective stage and means for concurrently operating said adjustable valve means of each stage.
  • ad justable valve means include movable valve members which are interconnected to move in unison.
  • adjustable valve means each include an axially slidable valve member which is biassed towards its full capacity position by the fluid pressure at the high pressure end of the respective stage, and comprising actuating means to move the valve members to and keep them in partial capacity positions.
  • the flexible member comprises a chain.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
  • Rotary Pumps (AREA)
  • Hydraulic Motors (AREA)
US00162244A 1970-07-16 1971-07-13 Two stage screw rotor machines Expired - Lifetime US3756753A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3452570A GB1365285A (en) 1970-07-16 1970-07-16 Meshing screw rotor positivedisplacement machines

Publications (1)

Publication Number Publication Date
US3756753A true US3756753A (en) 1973-09-04

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ID=10366730

Family Applications (1)

Application Number Title Priority Date Filing Date
US00162244A Expired - Lifetime US3756753A (en) 1970-07-16 1971-07-13 Two stage screw rotor machines

Country Status (6)

Country Link
US (1) US3756753A (fr)
JP (1) JPS5428603B1 (fr)
BE (1) BE769872A (fr)
CA (1) CA954098A (fr)
DE (1) DE2134994C3 (fr)
GB (1) GB1365285A (fr)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3869227A (en) * 1974-03-08 1975-03-04 Vilter Manufacturing Corp Variable capacity rotary screw compressor having variable high pressure suction fluid inlets
US3904322A (en) * 1972-06-30 1975-09-09 Stal Refrigeration Ab Screw compressor
US3936239A (en) * 1974-07-26 1976-02-03 Dunham-Bush, Inc. Undercompression and overcompression free helical screw rotary compressor
US4005949A (en) * 1974-10-10 1977-02-01 Vilter Manufacturing Corporation Variable capacity rotary screw compressor
USRE29283E (en) * 1974-07-26 1977-06-28 Dunham-Bush, Inc. Undercompression and overcompression free helical screw rotary compressor
US4261691A (en) * 1978-03-21 1981-04-14 Hall-Thermotank Products Limited Rotary screw machine with two intermeshing gate rotors and two independently controlled gate regulating valves
US4610613A (en) * 1985-06-03 1986-09-09 Vilter Manufacturing Corporation Control means for gas compressor having dual slide valves
US6283716B1 (en) 1997-10-28 2001-09-04 Coltec Industries Inc. Multistage blowdown valve for a compressor system
US6422846B1 (en) * 2001-03-30 2002-07-23 Carrier Corporation Low pressure unloader mechanism
US6638029B2 (en) 2001-12-19 2003-10-28 Hamilton Sunstrand Corporation Pressure ratio modulation for a two stage oil free compressor assembly
US20040040332A1 (en) * 2002-09-03 2004-03-04 Bitzer Kuehlmaschinenbau Gmbh Screw compressor
US20080206075A1 (en) * 2007-02-22 2008-08-28 Jean Louis Picouet Compressor Having a Dual Slide Valve Assembly
US20080240939A1 (en) * 2007-03-29 2008-10-02 Jean Louis Picouet Compressor Having a High Pressure Slide Valve Assembly
WO2009048446A1 (fr) * 2007-10-10 2009-04-16 Carrier Corporation Système de distributeur à tiroir pour compresseur à vis
US20090280017A1 (en) * 2006-10-16 2009-11-12 Carrier Corporation Compressor Slide Valve Support
US20120087821A1 (en) * 2010-10-06 2012-04-12 Agustawestland S.P.A. Pump Assembly, In Particular for Helicopter Lubrication
US9920763B2 (en) 2015-09-17 2018-03-20 Ingersoll-Rand Company Contact cooled rotary airend injection spray insert
US12055145B2 (en) 2021-07-21 2024-08-06 Copeland Industrial Lp Self-positioning volume slide valve for screw compressor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4610612A (en) * 1985-06-03 1986-09-09 Vilter Manufacturing Corporation Rotary screw gas compressor having dual slide valves

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR804327A (fr) * 1935-03-28 1936-10-21 Milo Ab Compresseur rotatif pourvu d'une denture helicoïdale, pour puissance variable
US2645903A (en) * 1947-02-20 1953-07-21 Douglas A Elkins Variable ratio rotary pump and motor hydraulic transmission
US2749571A (en) * 1951-06-23 1956-06-12 Pasquetti Carlo Machine for mixing and extruding
GB819485A (en) * 1956-04-12 1959-09-02 Svenska Rotor Maskiner Ab Improvements in gear devices acting as pumps or motors
US3088659A (en) * 1960-06-17 1963-05-07 Svenska Rotor Maskiner Ab Means for regulating helical rotary piston engines
US3314597A (en) * 1964-03-20 1967-04-18 Svenska Rotor Maskiner Ab Screw compressor
US3432089A (en) * 1965-10-12 1969-03-11 Svenska Rotor Maskiner Ab Screw rotor machine for an elastic working medium

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR804327A (fr) * 1935-03-28 1936-10-21 Milo Ab Compresseur rotatif pourvu d'une denture helicoïdale, pour puissance variable
US2645903A (en) * 1947-02-20 1953-07-21 Douglas A Elkins Variable ratio rotary pump and motor hydraulic transmission
US2749571A (en) * 1951-06-23 1956-06-12 Pasquetti Carlo Machine for mixing and extruding
GB819485A (en) * 1956-04-12 1959-09-02 Svenska Rotor Maskiner Ab Improvements in gear devices acting as pumps or motors
US3088659A (en) * 1960-06-17 1963-05-07 Svenska Rotor Maskiner Ab Means for regulating helical rotary piston engines
US3314597A (en) * 1964-03-20 1967-04-18 Svenska Rotor Maskiner Ab Screw compressor
US3432089A (en) * 1965-10-12 1969-03-11 Svenska Rotor Maskiner Ab Screw rotor machine for an elastic working medium

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3904322A (en) * 1972-06-30 1975-09-09 Stal Refrigeration Ab Screw compressor
US3869227A (en) * 1974-03-08 1975-03-04 Vilter Manufacturing Corp Variable capacity rotary screw compressor having variable high pressure suction fluid inlets
US3936239A (en) * 1974-07-26 1976-02-03 Dunham-Bush, Inc. Undercompression and overcompression free helical screw rotary compressor
USRE29283E (en) * 1974-07-26 1977-06-28 Dunham-Bush, Inc. Undercompression and overcompression free helical screw rotary compressor
US4005949A (en) * 1974-10-10 1977-02-01 Vilter Manufacturing Corporation Variable capacity rotary screw compressor
US4261691A (en) * 1978-03-21 1981-04-14 Hall-Thermotank Products Limited Rotary screw machine with two intermeshing gate rotors and two independently controlled gate regulating valves
US4610613A (en) * 1985-06-03 1986-09-09 Vilter Manufacturing Corporation Control means for gas compressor having dual slide valves
US6283716B1 (en) 1997-10-28 2001-09-04 Coltec Industries Inc. Multistage blowdown valve for a compressor system
US6371731B2 (en) 1997-10-28 2002-04-16 Coltec Industries Inc Multistage blowdown valve for a compressor system
US6478546B2 (en) 1997-10-28 2002-11-12 Coltec Industries Inc. Multistage blowdown valve for a compressor system
US6422846B1 (en) * 2001-03-30 2002-07-23 Carrier Corporation Low pressure unloader mechanism
US6638029B2 (en) 2001-12-19 2003-10-28 Hamilton Sunstrand Corporation Pressure ratio modulation for a two stage oil free compressor assembly
US20040040332A1 (en) * 2002-09-03 2004-03-04 Bitzer Kuehlmaschinenbau Gmbh Screw compressor
US6898948B2 (en) * 2002-09-03 2005-05-31 Bitzer Kuehlmaschinenbau Gmbh Screw compressor
US20090280017A1 (en) * 2006-10-16 2009-11-12 Carrier Corporation Compressor Slide Valve Support
US8021134B2 (en) * 2006-10-16 2011-09-20 Carrier Corporation Compressor slide valve support
US20080206075A1 (en) * 2007-02-22 2008-08-28 Jean Louis Picouet Compressor Having a Dual Slide Valve Assembly
US7891955B2 (en) 2007-02-22 2011-02-22 Vilter Manufacturing Llc Compressor having a dual slide valve assembly
WO2008121607A1 (fr) * 2007-03-29 2008-10-09 Vilter Manufacturing Llc Compresseur ayant un ensemble de soupape de glissement à haute pression
US20080240939A1 (en) * 2007-03-29 2008-10-02 Jean Louis Picouet Compressor Having a High Pressure Slide Valve Assembly
US8202060B2 (en) * 2007-03-29 2012-06-19 Vilter Manufactring LLC Compressor having a high pressure slide valve assembly
CN101680302B (zh) * 2007-03-29 2013-06-19 维尔特制造有限责任公司 具有高压滑阀组件的压缩机
WO2009048446A1 (fr) * 2007-10-10 2009-04-16 Carrier Corporation Système de distributeur à tiroir pour compresseur à vis
US20120087821A1 (en) * 2010-10-06 2012-04-12 Agustawestland S.P.A. Pump Assembly, In Particular for Helicopter Lubrication
US8668481B2 (en) * 2010-10-06 2014-03-11 Agustawestland S.P.A. Pump assembly, in particular for helicopter lubrication
US9920763B2 (en) 2015-09-17 2018-03-20 Ingersoll-Rand Company Contact cooled rotary airend injection spray insert
US12055145B2 (en) 2021-07-21 2024-08-06 Copeland Industrial Lp Self-positioning volume slide valve for screw compressor

Also Published As

Publication number Publication date
DE2134994C3 (de) 1979-12-20
BE769872A (fr) 1971-11-16
GB1365285A (en) 1974-08-29
DE2134994B2 (de) 1979-04-26
DE2134994A1 (de) 1972-01-20
JPS5428603B1 (fr) 1979-09-18
CA954098A (en) 1974-09-03

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