US3482768A - Compressor control system - Google Patents

Compressor control system Download PDF

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Publication number
US3482768A
US3482768A US709110A US3482768DA US3482768A US 3482768 A US3482768 A US 3482768A US 709110 A US709110 A US 709110A US 3482768D A US3482768D A US 3482768DA US 3482768 A US3482768 A US 3482768A
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Prior art keywords
compressor
liquid
oil
valve
flow
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Expired - Lifetime
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US709110A
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English (en)
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Gilbert Cirrincione
Robert R Anderson
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Gardner Denver Inc
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Gardner Denver Inc
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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
    • F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
    • F04C29/0007—Injection of a fluid in the working chamber for sealing, cooling and lubricating
    • F04C29/0014—Injection of a fluid in the working chamber for sealing, cooling and lubricating with control systems for the injection of the fluid

Definitions

  • Excess liquid is purged from the liquid injection system by venting compressed gas into the compressor liquid injection gallery.
  • the self-regulating valve provides substantially reduced flow of liquid during the unloaded running condition and together with the compressed gas purging action eliminates the vibration and noise caused by high liquid injection rates, and prevents choking or flooding of the compressor.
  • Conventional positive displacement rotary gas compressor units include a class of machines in which a liquid is continually injected into the compression chamber of the compressor in large quantities for cooling the gas being compressed, as well as for lubricating and gas tight sealing the working mechanism of the compressor.
  • These compressor units usually include a combination compressed gas receiver-liquid reservoir tank located downstream of the compressor discharge passage where separation of the liquid from the compressed gas is attained.
  • the liquid is usually recirculated by .-a metering pump via attendant devices such as filters and heat exchangers to provide continuous injection into the compressor.
  • the invention resides in the provision in a control system for positive displacement rotary compressors of the liquid injected type of a flow control valve for restricting the rate of liquid injected into the compressor when run ning in the unloaded condition.
  • the invention also provides for a liquid flow control valve that is self-regulating to permit maximum flow of injection liquid during periods of loaded operation of the compressor and operable to limit the amount of liquid injected during periods of unloaded operation to a desired proportional amount of the loaded injection rate.
  • This proportional flow rate is achieved by a spring loaded valve element which reacts to a predetermined pressure in the liquid injection line to the compressor during loaded operation to permit suitable injection rates for efiicient operation.
  • the pressure on the valve is insuflicient to prevent the valve from closing whereby flow of liquid to the compressor under such conditions is metered by a properly sized orifice located in the valve element.
  • the invention also provides for purging excess oil from the compressor interior by utilizing the venting of compressed gas from the compressor system at the onset of unloaded operation to rapidly displace excess oil remaining in the system downstream of the flow control valve.
  • liquid injected compressor units of the type discussed herein may be operated more etficiently than heretofore realized.
  • FIG. 1 is a schematic illustration of a liquid injected gas compressor system embodying the present invention.
  • FIG. '2 is a sectional view of a portion of a typical rotary liquid injected compressor casing illustrating details of the self-regulating liquid flow control valve.
  • FIG. 1 represents a compressor system characterized by a positive displacement liquid injected rotary compressor.
  • C mpressors of this type are generally categorized as being of either the sliding vane or helical screw design although other types are known and used to a lesser degree in the art.
  • Such compressors are widely used for industrial compressed air systems, in the construction industry, and various applications for compressing gases other than air.
  • the injection liquid is a lightweight mineral oil, although special systems have used water, condensed vapors, and various other liquids.
  • FIG. 1 will be considered to be that of an inddustrial plant air compressor unit having an oil injected, helical screw compressor generally designated by numeral driven by an electric motor 12.
  • the compressor 10 is equipped with an inlet throttling valve 14 actuated by a valve operator 16.
  • An inlet air cleaner 18 is shown mounted upstream of the valve 14.
  • Compressed air and oil are discharged from the compressor 10 through a discharge line 20 to a combined air receiver-oil reservoir tank 22 which may contain suitable means for separating from the compressed air virtually all liquid such as the oil and condensed water vapor.
  • the liquid free air then flows through conduit 24 and check valve 26 to a compressed air storage tank 28.
  • the valve 30 provides control over compressed air flowing from the tank 28 to the end usage.
  • the tank 28 may be eliminated since the network of piping making up the distribution system serves as adequate storage capacity for the compressed air.
  • the compressor oil injection system includes the com bination air receiver-oil reservoir tank 22 serving as a source of injection oil from which extends an oil supply line 32 leading to a filter 34.
  • a continuing oil supply line 36 leads to a heat exchanger 38 and from that com ponent line 40 connects to a flow control valve housing 42 located on the compressor casing 44.
  • c ntrol components of the compressor system which include a conduit 46 in communication with the compressed air storage tank 28 and a pilot or self-actuated valve 48 which is responsive to a predetermined pressure in the conduit 46 to open and admit pressure air to the conduit 50 which is in communication with the valve operator 16. Also connected to the conduit 50 is a pressure switch 52 whose purpose will be discussed herein.
  • a vent conduit 54 leading to a normally open solenoid valve 56.
  • the valve 56 is electrically connected to the pressure switch 52 by suitable means (not shown) and is controlled to be closed when energized, that is when the switch 52 is closed. Downstream of the valve 56 a conduit 58 leads to an exhaust muffler 60 vented to atmosphere and a secondary conduit 62 leads through a flow restrictor 64 and a check valve 66 to the flow control valve housing 42.
  • the flow control valve housing 42 is illustrated fastened to the compressor casing 44 by suitable means, not shown, and having an interior portion 68 opening into the compressor oil injection gallery 70. Communicating with the gallery 70 is passage .72 which leads to various locations within the compressor which require lubrication and cooling such as bearings, drive gears and seals. As shown in FIG. 2, the housing 42 comprises a cover for liquid injection gallery 70. Also in communication with the gallery 70 are the main oil injection ports 74 which communicate directly with the compression chamber of the compressor. Secondary oil injection ports 76 receive drainage oil from the aforementioned bearings, etc., via passages 78 opening into cavities 80.
  • the oil injection flow control valve designated in its entirety by 82 comprises a plug member 84 having a hollow interior 85 partially threaded for receiving the conduit 40.
  • the plug member 84 is threadedly disposed in the housing 42 and forms a seat for a valve closure plate 86 which is biased to the closed position by a coil spring 88.
  • a bypass orifice 90 in the valve plate 86 is sized to permit a predetermined flow of oil into the gallery when the valve is closed.
  • a spring and closure plate retainer 92 is suitably secured to the plug 84 by pins 94 which also serve to guide the closure plate.
  • a plug 96 is threadedly disposed in the housing 42 also, and connected thereto is the secondary vent line 62 which communicates with the interior 68 of the valve housing 42 via the passage 98.
  • the function of the oil flow control valve and the compressor system in general can best be explained by a discussion of the operation of the system.
  • the compressor system shown is typical of the type provided for industrial plants for compressing atmospheric air to nominal pressures in the range of 100 to p.s.i.g. depending on plant requirements.
  • the system with the motor deenergized and no pressure air in the tank 28 will find the pilot valve 48 closed, the throttling valve 14 is also lightly biased to be closed, and the solenoid valve 56 open.
  • the compressor unit is started by closing a switch on a motor starter unit, not shown, to energize the motor.
  • the pressure switch 52 also suitably electrically connected to the motor starter unit and being in the closed position, will permit energization of the solenoid valve 56 to close the same.
  • a near total vacuum is momentarily created in the compressor inlet creating a pressure differential across the compressor throttling valve 14 sufficient to open the valve and admit air to the compressor.
  • valve 30 is closed or nearly closed prior to compressor startup so that pres sure in the receiver-reservoir tank 22 and the storage tank 28 builds up rapidly and oil commences to flow from the tank 22 through the injection supply system consisting of the conduit 32, filter 34, conduit 36, heat exchanger 38, and conduit 40 to the fiow control valve 82.
  • the flow control valve closure plate 86 will be forced fully open to provide full oil flow to the compressor 10.
  • the compressor system is now running with full oil and inlet air flow to supply compressed air to the end usage.
  • pilot valve 48 As demand for compressed air downstream of the service valve 30 decreases pressure in the storage tank 28 and receiver-reservoir 22 will rise to a preset unload value sensed by the pilot valve 48, for example, 100 p.s.i.g.
  • the self-actuating pilot valve will commence the unloading cycle by opening to admit pressure air to the conduit 50 to be sensed by the pressure switch 52 and the inlet valve operator 16 whereupon, simultaneously, the switch will open to deenergize the solenoid valve 56 opening the same, and the operator 16 will actuate to close the compressor inlet valve 14 shutting ofi the supply of inlet air to the compressor.
  • Opening the solenoid valve 56 will result in the venting of the receiver-reservoir tank 22 to atmosphere through the vent conduit 58 and mufiier 60.
  • the check valve 26 prevents back flow of compressed air from the storage tank 28.
  • a quantity of pressure air will flow through the secondary vent conduit 62 and into the flow control housing 42 to purge or scavenge excess oil present therein and in the injection gallery 70 by forcing the oil through the injection ports 74.
  • the interior of the compressor in and near the inlet will also be evacuated to a near total vacuum caused by the pumping action of the compressor. This vacuum condition will also exist in the interior of the valve housing and the oil injection gallery due to the fact that the injection ports 74 and 76 communicate with the compression chamber in the vicinity of the compressor inlet.
  • the pressure difierential across the flow control valve is essentially one atmosphere and the closure plate 86 urged by the spring 88 will close permitting only enough oil to fioW to the compressor as determined by the bypass orifice 90 in the closure plate.
  • the oil flow control valve 82 is desirably located as close to the compressor as is practical, the purpose being in this respect to minimize the quantity of excess oil required to be purged between the flow control valve and the interior of the compressor at the onset of the unloading cycle.
  • a small quantity of air will flow from the reservoir tank 22, through the vent conduits 58, and the secondary vent conduit 62, to mix with the reduced quantity of oil flowing through the interior 68 of the flow control valve housing 42 and provide an atomized oil-air mixture which further reduces vibration and noise in the compressor.
  • the oil-air mixture is, of course, eventually pumped through the compressor and into the reservoir tank via the discharge line 20.
  • the flow restrictor 64 limits the quantity of air fiowing to the compressor under these conditions to an amount inconsequential to compressor power demand.
  • the resumption or increase in pressure air demand will cause the pressure in the storage tank 28 to drop and upon reaching a preset minimum the pilot valve 48 will shift to close and vent the conduit 50.
  • the compressor will then resume loaded operation as the switch 52 closes to energize the solenoid valve 56 to prevent venting of the receiver-reservoir tank, and the compressor inlet valve 14 will open to permit full inlet air flow to the compressor.
  • Pressure increase in the receiver-reservoir tank 22 will again force full oil flow as the flow control valve 82 opens in response to the increased pressure differential.
  • the flow control valve 82 may be located at other points in the injection liqirid supply system between the receiver-reservoir tank 22 and the compressor 10 with, however, less desirable results.
  • the pump may be advantageously driven by an auxiliary drive shaft On the compressor or by separate drive means. In such a case it is desirable to position the oil flow control valve upstream of the pump so that the valve may still be operative in the unloaded condition to provide for a reduced oil flow rate.
  • the system disclosed need not be limited to industrial air compressors, but could be applied to many applications involving liquid injected rotary compressors.
  • rotary gas compressor means having gas inlet and discharge means and liquid injection port means; a liquid source havnig pressurized and vented conditions; supply means communicating liquid from said source to said injection port means; and the improvement comprising:
  • said control valve means in circuit with said supply means operable to provide maximum liquid flow to said injection port means when said source is pressurized and regulated liquid flow when said source is vented, said valve means including flow regulating bypass means eflective when said source is vented to limit liquid flow.
  • said source of liquid comprises a compressed gas-liquid reservoir tank connected to said compressor discharge means; said reservoir tank operable to be in a gas pressurized condition and in a vented condition thereby establishing a first pressure differential and a reduced pressure differential, respectively, between said reservoir tank and said liquid injection port means in said compressor; and said flow control valve comprises a closure member responsive to said first pressure differential acting thereon to open thereby providing said maximum liquid.
  • said flow control valve includes resilient means acting on said closure member to bias said closure member to close.
  • said bypass means in said flow control valve comprises orifice means in said closure member.
  • said fiow control valve includes valve housing means, said housing means being located substantially on said compresor means and adjacent said liquid injection port means in said compressor whereby the volume of liquid in said conduit means between said flow control valve and said liquid injection port means is minimized.
  • liquid purging means comprising conduit means in communication with said compressor and Said liquid reservoir tank, said purging means being operable to conduct pressure gas from said reservoir tank to said compressor for purging excess liquid from within said compressor.
  • said purging conduit means is in communication with said liquid conduit means between said flow control valve and said liquid injection port means in said compressor.
  • rotary gas compressor means having gas inlet and discharge means and liquid injection port means; combined gas receiver and liquid reservoir means operably connected to said compressor for receiving compressed gas therefrom and operable to be in a gas pressurized condition and a vented condition; liquid supply means connecting said reservoir with said injection port means, said supply means including gallery means on said compressor in communication with said liquid injection port means, said gallery means having a cover member; and the improvement comprising:
  • liquid purging means comprising conduit means connecting said gas receiver and said gallery means, said liquid purging means including valve means in circuit with said conduit means and operable to vent said receiver-reservoir means to said conduit means whereby in response to venting said receiver-reservoir means liquid is purged directly from said gallery means.
  • rotary gas compressor means having gas inlet and discharge means and liquid injection port means, said compressor means being operable to be in a loaded condition and an unloaded condition;
  • liquid source having a pressurized condition when said compressor is loaded and a vented condition when said compressor is unloaded
  • liquid supply means communicating liquid from said source to said injection port means;
  • control valve means in circuit with said supply means for regulating liquid flow to said injection port means when said source is vented.
  • rotary gas compressor means having gas inlet and discharge means and liquid injection port means;
  • liquid injection means comprising a source of liquid and liquid supply means connecting said source with said injection port means;
  • compressed gas receiver means operably connected to said compressor for receiving compressed gas therefrom;
  • liquid purging means comprising conduit means connecting said gas receiver means with said liquid supply means between said fiow control means and said injection port means, said purging means being operable to vent compressed gas from said receiver means to said liquid supply means for purging liquid therefrom.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
US709110A 1968-02-28 1968-02-28 Compressor control system Expired - Lifetime US3482768A (en)

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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3632231A (en) * 1970-02-19 1972-01-04 Worthington Corp Suction pressure relieving system for a rotary vane compressor
US3653191A (en) * 1969-10-16 1972-04-04 Gardner Denver Co Receiver-separator unit for liquid injected gas compressor
US4025244A (en) * 1974-12-24 1977-05-24 Hokuetsu Kogyo Co., Ltd. Rotary compressor of liquid-cooled type provided with means for adjusting amount of liquid and volume of gas
US4063855A (en) * 1976-05-03 1977-12-20 Fuller Company Compressor capacity and lubrication control system
US4070166A (en) * 1975-01-24 1978-01-24 Atlas Copco Aktiebolag Method and device for driving liquid from a liquid separator
EP0000131A1 (fr) * 1977-06-17 1979-01-10 ALSTHOM-ATLANTIQUE Société anonyme dite: Procédé et dispositif de lubrification de compresseurs
US4171188A (en) * 1976-08-03 1979-10-16 Chicago Pneumatic Tool Company Rotary air compressors with intake valve control and lubrication system
EP0067949A2 (de) * 1981-06-05 1982-12-29 Bauer Schraubenverdichter Gmbh Ventilblock für das Steuern der Ölzufuhr eines Schraubenverdichters
US4741675A (en) * 1986-08-04 1988-05-03 Hydreco, Incorporated Flow control system for a hydraulic pump
US5097677A (en) * 1988-01-13 1992-03-24 Texas A&M University System Method and apparatus for vapor compression refrigeration and air conditioning using liquid recycle
US5667367A (en) * 1994-04-08 1997-09-16 Kabushiki Kaisha Kobe Seiko Sho Air compressor
US5803715A (en) * 1991-10-14 1998-09-08 Cash Engineering Research Pty. Ltd. Inlet control combination for a compressor system
US6059540A (en) * 1997-09-22 2000-05-09 Mind Tech Corp. Lubrication means for a scroll-type fluid displacement apparatus
US6193487B1 (en) 1998-10-13 2001-02-27 Mind Tech Corporation Scroll-type fluid displacement device for vacuum pump application
EP1043501A3 (de) * 1999-04-10 2001-02-28 Druckluft Dannöhl GmbH Ölfilter für einen mehrstufigen Kolbenverdichter
US6792968B1 (en) 2000-05-30 2004-09-21 Robert H. Breeden Pump assembly and method
WO2014151762A2 (en) * 2013-03-15 2014-09-25 SHELLING, Judith G. Electromechanical apparatus, system and methods for dispensing or purging fluids
US20150369429A1 (en) * 2014-06-23 2015-12-24 SMC Pneumatics (Australia) Pty Ltd Factory compressed air supplies
US9915265B2 (en) 2014-12-31 2018-03-13 Ingersoll-Rand Company Compressor system with variable lubricant injection orifice

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1877345A (en) * 1928-10-31 1932-09-13 Swiss Locomotive & Machine Works Cooling water regulator for rotary compressors
US2470655A (en) * 1944-06-12 1949-05-17 Allis Chalmers Mfg Co Cooling and lubrication of compressors
US2654532A (en) * 1946-10-30 1953-10-06 Nichols Thomas Winter Rotary compressor
US3105630A (en) * 1960-06-02 1963-10-01 Atlas Copco Ab Compressor units

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1877345A (en) * 1928-10-31 1932-09-13 Swiss Locomotive & Machine Works Cooling water regulator for rotary compressors
US2470655A (en) * 1944-06-12 1949-05-17 Allis Chalmers Mfg Co Cooling and lubrication of compressors
US2654532A (en) * 1946-10-30 1953-10-06 Nichols Thomas Winter Rotary compressor
US3105630A (en) * 1960-06-02 1963-10-01 Atlas Copco Ab Compressor units

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3653191A (en) * 1969-10-16 1972-04-04 Gardner Denver Co Receiver-separator unit for liquid injected gas compressor
US3632231A (en) * 1970-02-19 1972-01-04 Worthington Corp Suction pressure relieving system for a rotary vane compressor
US4025244A (en) * 1974-12-24 1977-05-24 Hokuetsu Kogyo Co., Ltd. Rotary compressor of liquid-cooled type provided with means for adjusting amount of liquid and volume of gas
US4070166A (en) * 1975-01-24 1978-01-24 Atlas Copco Aktiebolag Method and device for driving liquid from a liquid separator
US4063855A (en) * 1976-05-03 1977-12-20 Fuller Company Compressor capacity and lubrication control system
US4171188A (en) * 1976-08-03 1979-10-16 Chicago Pneumatic Tool Company Rotary air compressors with intake valve control and lubrication system
EP0000131A1 (fr) * 1977-06-17 1979-01-10 ALSTHOM-ATLANTIQUE Société anonyme dite: Procédé et dispositif de lubrification de compresseurs
EP0067949A2 (de) * 1981-06-05 1982-12-29 Bauer Schraubenverdichter Gmbh Ventilblock für das Steuern der Ölzufuhr eines Schraubenverdichters
EP0067949A3 (en) * 1981-06-05 1983-01-12 Bauer Schraubenverdichter Gmbh Valve block for controlling the oil supply of a screw compressor
US4741675A (en) * 1986-08-04 1988-05-03 Hydreco, Incorporated Flow control system for a hydraulic pump
US5097677A (en) * 1988-01-13 1992-03-24 Texas A&M University System Method and apparatus for vapor compression refrigeration and air conditioning using liquid recycle
US5803715A (en) * 1991-10-14 1998-09-08 Cash Engineering Research Pty. Ltd. Inlet control combination for a compressor system
US5667367A (en) * 1994-04-08 1997-09-16 Kabushiki Kaisha Kobe Seiko Sho Air compressor
US6059540A (en) * 1997-09-22 2000-05-09 Mind Tech Corp. Lubrication means for a scroll-type fluid displacement apparatus
US6193487B1 (en) 1998-10-13 2001-02-27 Mind Tech Corporation Scroll-type fluid displacement device for vacuum pump application
EP1043501A3 (de) * 1999-04-10 2001-02-28 Druckluft Dannöhl GmbH Ölfilter für einen mehrstufigen Kolbenverdichter
US6792968B1 (en) 2000-05-30 2004-09-21 Robert H. Breeden Pump assembly and method
WO2014151762A2 (en) * 2013-03-15 2014-09-25 SHELLING, Judith G. Electromechanical apparatus, system and methods for dispensing or purging fluids
WO2014151762A3 (en) * 2013-03-15 2014-12-18 SHELLING, Judith G. Electromechanical apparatus, system and methods for dispensing or purging fluids
GB2528409A (en) * 2013-03-15 2016-01-20 Martin Dunn Electromechanical apparatus, system and methods for dispensing or purging fluids
US20150369429A1 (en) * 2014-06-23 2015-12-24 SMC Pneumatics (Australia) Pty Ltd Factory compressed air supplies
US9915265B2 (en) 2014-12-31 2018-03-13 Ingersoll-Rand Company Compressor system with variable lubricant injection orifice

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