US3766747A - Liquid sensor for reciprocating refrigerant compressor - Google Patents

Liquid sensor for reciprocating refrigerant compressor Download PDF

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Publication number
US3766747A
US3766747A US00215752A US3766747DA US3766747A US 3766747 A US3766747 A US 3766747A US 00215752 A US00215752 A US 00215752A US 3766747D A US3766747D A US 3766747DA US 3766747 A US3766747 A US 3766747A
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United States
Prior art keywords
compressor
liquid
electric motor
valve mechanism
piston means
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Expired - Lifetime
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US00215752A
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English (en)
Inventor
S Parker
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Lennox Industries Inc
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Lennox Industries Inc
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00Compressor arrangements
    • F25B31/02Compressor arrangements of motor-compressor units
    • F25B31/023Compressor arrangements of motor-compressor units with compressor of reciprocating-piston type
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B35/00Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
    • F04B35/04Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for the means being electric
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06Control using electricity
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/10Other safety measures

Definitions

  • a serious problem causing valve breakage and damage in reciprocating refrigerant compressors is the slugging condition at start-up which results when liquid rather than gas enters the valve mechanism.
  • Such liquid may be lubricant (oil), refrigerant, or combinations of the named liquids.
  • a refrigeration system is comprised of a compressor, a first heat exchanger or condenser, expansion means and a second heat exchanger or evaporator. Refrigerant gas is compressed in the compressor and the high pressure vaporous refrigerant passes through a discharge line to the condenser where it is condensed.
  • the flow of refrigerant from the condenser to the evaporator is controlled by the expansion means which may be either a capillary tube or a thermal expansion valve. Expanding gas in the evaporator absorbs heat and the medium passing over the evaporator (air or water) is cooled. The refrigerant gas flows back to-the compressor through the suction line.
  • the expansion means which may be either a capillary tube or a thermal expansion valve. Expanding gas in the evaporator absorbs heat and the medium passing over the evaporator (air or water) is cooled. The refrigerant gas flows back to-the compressor through the suction line.
  • a lubricant sump is commonly provided within the reciporcating refrigerant compressor.
  • Lubricant is migrate-to'the compressor.- Primarly, three factors de-- termine the rate at which refrigerant is absorbed in the oil.
  • One is the vapor pressure differential at a stabilized temperature which causes a driving force forcing the refrigerant vapor in the system to flow to the oilrefrigerant mixture in the compressor sump.
  • a second factor is theactual temperature differential between the refrigerant and oi]. These factors are closely related as the vapor pressure is responsive to temperature and the vaporpressure is basically the driving force.
  • a third factor is the amount of oil surface exposed to the refrigerant vapor. As the major portion of the oil in the refrigerant system is in the compressor sump, the
  • the condensing unit is sometimes placed exposed to the sun, and in the spring the sun will warm the condenser more rapidly than the compressor, with the result that notwithstanding the use of a heater in the compressor, the compressor might actually be colder than the condenser or there would be insufficient temperature differential such that refrigerant would migrate to the compressor.
  • liquid will be present in the entrance to the vale mechanism and during the compression stroke and/or suction stroke, damage can result to the valving.
  • refrigerant condenses within the refriger ant system may also accumulate at the entrance to the valve mechanism of the compressor. Since the liquid would be incompressible upon start-up of the compressor, it too might result in damage to the valve mechanism.
  • An object of the present invention is to provide improved reciprocating refrigerant compressor control means and method for preventing operation of the compressor in the event there is an undesirable quantity of liquid at the entry of the valve mechanism.
  • Another object of the present invention is to provide an improved method for operating a refrigerant compressor which comprises the step of preventing operation ofthe motor in the compressor in the event a predetermined quantity of liquid is sensed at the inlet to the .valve mechanism.
  • Yet another object of this invention is to provide a reciprocating refrigerant compressor with an improved control including a state of matter disposed adjacent to the inlet to the valve mechanism for sensing a predetermined liquid condition at such location and preventing operation of the compressor until such liquid condition is obviated.
  • Yet another object of the present invention is toprovide a reciprocating refrigerant compressor having improved means -for controlling the operation thereof, such improved control means comprising a liquid sensorfor-detecting a predetermined liquid condition at the entry to the suction valving of the reciprocating compressor.
  • FIG. 1 is a cross-sectional.elevation view of a reciprocating refrigerant compressor embodying principlesof the present invention, with a typical refrigeration system within which the compressor isdisposed being shown schematically; and.
  • FIG. 2 is a schematic wiring diagram of the control circuit for the compressor of FIG. 1.
  • the expansion means 14 which may be either a capillary tube or a thermal expansion valve controls the flow of refrigerant from the condenser 12 to the evaporator 16.
  • the refrigerant is returned to the compressor from the evaporator through suction line 17.
  • the condenser is aircooled or water-cooled in order to effect condensing of the high pressure vaporous refrigerant. Air or water passing over the evaporator would be cooled by the expansion of the refrigerant therein and would be forwarded by suitable duct or conduit to the area to be cooled.
  • the reciprocating refrigerant compressor 10 comprises a gas-tight outer housing or casing which includes an upper shell 22, a lower shell 24 integrally joined to one another as, for example, by welding.
  • a plurality of legs 26 are suitably secured to the compressor 10 to support it in an upright position.
  • the compression mechanism includes a compressor block 34 having defined therein cylinder means 36.
  • the cylinder means may comprise one or more cylinders in the compressor block or may be a cylinder liner disposed'in a suitable opening in the compressor block.
  • Movable within each cylinder means 36 is a piston 38 which is adapted to be driven from the drive shaft 40 which is actuated by power means 42.
  • the power means 42 preferably comprise an electric motor having a stator 41 secured to the compression mechanism and a rotor 43 inductively connected to the stator 41 and fixedly secured to the drive shaft 40 to rotate same.
  • valve assembly 46 Provided at the end of each cylinder 36 and closing the end of each cylinder cavity is a valve assembly 46.
  • the valve assembly includes a discharge valve 48 and a suction valve 50.
  • the suction valve will open on the suction stroke of the piston to permit refrigerant gas (suction gas) to enter the cylinder.
  • suctionvalve On the compression stroke, the suctionvalve will be closed and the discharge valve opened to permit the flow of compressed refrigerant gas to the discharge muffler in the compression mechanism and then to the discharge line for forwarding to the condenser.
  • suction valve damage or breakage will occur on the discharge or compressor stroke.
  • a feature of this invention is the provision of a state of matter sensor 60 adjacent the entrance to the valve mechanism 46.
  • the state of matter sensor 60 is spaced as closely as possible to the entrance of the valve mechanism 46 so as to sense the presence of a predeter' mined quantity of liquid and to prevent operation of the compressor motor in the event there is a sufficientquantity of liquid that would cause damage to the compressor valve assembly 44 upon startup.
  • the state of matter sensor comprises a liquid sensor and takes the form of a thermistor.
  • the liquid sensing thermistor may be of the type made by Controls Company of America.
  • state of matter sensor can be varied as, for example, a float sensor, a sonic sensor, or an optical sensing arrangement can be utilized.
  • FIG. 2 a schematic wiring diagram for the compressor 10.
  • the motor 42 is connected to lines T and T through contacts a and 70b of relay coil 70. When contacts 70a and 70b are closed, the motor will be energized.
  • the relay coil 70 is in a series circuit called a pilot cicuit with a plurality of actuating and safety switches that are connected to lines L, and L that receive power from a suitable source, for example, a low-voltage transformer.
  • the switches in the pilot circuit may include a thermal responsive switch 72 (normally open) that is adapted to close upon demand for cooling in an area to be cooled.
  • the switch 74 may be a normally closed motor safety switch adapted to open if the temperature of the motor should exceed a predetermined value.
  • Swtich 76 is the liquid sensor itself or alternatively it may be a normally closed switch actuable in response to the liquid sensor.
  • the switch 74 is normally closed, as is switch 76.
  • Switch 72 is closed when there is a demand for cooling, closing the circuit through relay coil 70 to energize the coil.
  • Contacts 70a and 70b are closed upon energization of coil 70 to energize motor 42. Should the motor temperature exceed a predetermined value, switch 74 will open to deenergize coil 70 and break the circuit to motor 42.
  • switch 76 will be opened to deenergize the coil 70.
  • the thermistor liquid sensor 60 has a relatively high internal resistance when immersed in liquid and a relatively low resistance when in a gaseous medium.
  • the thermistor 60 is used to control switch 76 in series with relay coil 70 in the pilot circuit to prevent operation of the compressor motor 42 in the event an undesirable liquid quantity is in the area ofthe inlet to the compressor valve mechanism.
  • switch 76 could be actuated through different means, for example, switch 60 might be a magnetically actu ated float switch, an optically actuated switch, or a sonic actuated switch.
  • crankcase heater is often used to heat the lubricant in the sump of the compressor and/or the compressor block.
  • -switch 76 will again close and restore the pilot circuit to a complete circuit.
  • Coil 70 may be energized to again close switch contacts 70a and 70b to again start the motor 42.
  • a unique feature of this invention is the sensing of 3 liquid condition rather than a pressure or temperature condition of the suction gas or of the oil.
  • 3,426,962 discloses a sensor for detecting the presence of oil in the refrigerant sump in a compressor to insure that there is adequate lubrication.
  • the gist of this patent is unlike that of the present invention.
  • the present invention is unique in that it senses the presence of liquid in the area adjacent the inlet to the suction valve in the compressor to prevent primary slugging of refrigerant.
  • shutting off a reciprocating refrigerant compressor should liquid accumulate adjacent a valve mechanism which is at the same temperature as the refrigerant gas. It should be stressed that because of the thermodynamics of the working refrigerant fluid, temperature sensing is not adequate, and one must depend upon a state of matter sensor.
  • a refrigerant compressor including an outer housing compression mechanismin the housing, cylinder and piston means in said compression mechanism, valve mechanism for controlling the flow of fluid to and from said cylinder and piston means, a sump for lubricant being defined in said housing and power means for actuating the piston means, characterized by the improvement comprising a state of matter sensor disposed adjacent the inlet to the valve mechanism for sensing a predetermined liquid condition at such location and preventing operation of the compressor until such liquid condition has been obviated said valve mechanism including suction valving said power means comprising an electric motor, said state of matter sensor comprising a thermistor secured to the compression mechanism and electrically connected in circuit with the electric motor for detecting the presence of an undesired quantity of liquid at the entrance to the suction valving.
  • a method of controlling the operation of a refrigerant compressor including an outer housing, compression mechanism in the housing, cylinder and piston means in the compression mechanism, valve mechanism for controlling the flow of fluid to and from the cylinder and piston means, a sump for lubricant defined in the housing, and power means comprising an electric motor for actuating the piston means, comprising the steps of actuating the electric motor in response to predetermined temperature conditions in a zone to be treated and preventing operation of the electric motor by sensing a predetermined liquid condition adjacent the inlet to the valve mechanism in the compressor, and permitting operation of the electric motor when such liquid condition has been obviated, thereby preventing damage to the valve mechanism.
  • a refrigerant compressor including an outer housing, compression mechanism in the housing, cylinder and piston means in said compression mechanism, valve mechanism cooperating with the cylinder and piston means, and power means for actuating the piston means comprising an electric motor
  • the improvement comprising a state of matter sensor disposed adjacent thefinlet to the valve mechanism for sensing the presence of an undesired quantity of liquid at the inlet to the valve mechanism, and said state of matter sensor being connected in circuit with said electric motor for preventing operation of the electric motor until the presence of the undesired quantity of liquid is no longer sensed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Compressor (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
US00215752A 1972-01-06 1972-01-06 Liquid sensor for reciprocating refrigerant compressor Expired - Lifetime US3766747A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US21575272A 1972-01-06 1972-01-06

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US3766747A true US3766747A (en) 1973-10-23

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US00215752A Expired - Lifetime US3766747A (en) 1972-01-06 1972-01-06 Liquid sensor for reciprocating refrigerant compressor

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US (1) US3766747A (it)
CA (1) CA990960A (it)
DE (1) DE2300377A1 (it)
FR (1) FR2167786B1 (it)
GB (1) GB1406793A (it)
IT (1) IT976751B (it)
NL (1) NL7300202A (it)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4506519A (en) * 1983-08-24 1985-03-26 Tecumseh Products Company Hermetic compressor discharge line thermal block
US4884412A (en) * 1988-09-15 1989-12-05 William Sellers Compressor slugging protection device and method therefor
DE4002196A1 (de) * 1989-01-26 1990-08-09 Diesel Kiki Co Verdichter mit variabler kapazitaet
US5209076A (en) * 1992-06-05 1993-05-11 Izon, Inc. Control system for preventing compressor damage in a refrigeration system
US20040194485A1 (en) * 2003-04-04 2004-10-07 Dudley Kevin F. Compressor protection from liquid hazards
WO2004104419A1 (en) * 2003-05-22 2004-12-02 Empresa Brasileira De Compressores S.A. Embraco A sensor assembly, a fluid pump and a cooler
US20050147500A1 (en) * 2003-12-30 2005-07-07 Ioan Sauciuc Method and apparatus for two-phase start-up operation
US20060018763A1 (en) * 2004-07-22 2006-01-26 Akio Uratani Hermetic compressor
US20120257990A1 (en) * 2009-12-29 2012-10-11 Erikson Klas Goeran Control of subsea compressors
WO2016113903A1 (ja) * 2015-01-16 2016-07-21 三菱電機株式会社 圧縮機
CN108374783A (zh) * 2017-01-31 2018-08-07 泰肯贸易股份公司 通过吸液进行吸入的方法和吸液装置
US20190264973A1 (en) * 2018-02-26 2019-08-29 Ronald Koelsch Zone isolation control system for transport refrigeration units
US20210340967A1 (en) * 2018-11-08 2021-11-04 Panasonic Appliances Regrigeration Devices Singapore Refrigerant compressor and refrigeration apparatus using the same
US12072127B2 (en) * 2021-06-17 2024-08-27 Carrier Corporation Refrigeration system and oil recovery method for the same

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2448403A (en) * 1943-11-11 1948-08-31 Manning Maxwell & Moore Inc Apparatus for maintaining optimum conditions in gaseous mediums
US2534455A (en) * 1944-06-08 1950-12-19 Honeywell Regulator Co Refrigerating control apparatus
US2871673A (en) * 1956-10-08 1959-02-03 H A Phillips Company Liquid return system
US3232519A (en) * 1963-05-07 1966-02-01 Vilter Manufacturing Corp Compressor protection system
US3290576A (en) * 1964-05-12 1966-12-06 Westinghouse Electric Corp Detectors of fluid flow
US3411313A (en) * 1966-12-02 1968-11-19 Carrier Corp Compressor protective control

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2448403A (en) * 1943-11-11 1948-08-31 Manning Maxwell & Moore Inc Apparatus for maintaining optimum conditions in gaseous mediums
US2534455A (en) * 1944-06-08 1950-12-19 Honeywell Regulator Co Refrigerating control apparatus
US2871673A (en) * 1956-10-08 1959-02-03 H A Phillips Company Liquid return system
US3232519A (en) * 1963-05-07 1966-02-01 Vilter Manufacturing Corp Compressor protection system
US3290576A (en) * 1964-05-12 1966-12-06 Westinghouse Electric Corp Detectors of fluid flow
US3411313A (en) * 1966-12-02 1968-11-19 Carrier Corp Compressor protective control

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4506519A (en) * 1983-08-24 1985-03-26 Tecumseh Products Company Hermetic compressor discharge line thermal block
US4884412A (en) * 1988-09-15 1989-12-05 William Sellers Compressor slugging protection device and method therefor
DE4002196A1 (de) * 1989-01-26 1990-08-09 Diesel Kiki Co Verdichter mit variabler kapazitaet
US5209076A (en) * 1992-06-05 1993-05-11 Izon, Inc. Control system for preventing compressor damage in a refrigeration system
AU2004230692B2 (en) * 2003-04-04 2008-05-15 Carrier Corporation Compressor protection from liouid hazards
US20040194485A1 (en) * 2003-04-04 2004-10-07 Dudley Kevin F. Compressor protection from liquid hazards
WO2004092686A2 (en) * 2003-04-04 2004-10-28 Carrier Corporation Compressor protection from liouid hazards
WO2004092686A3 (en) * 2003-04-04 2005-01-27 Carrier Corp Compressor protection from liouid hazards
US6886354B2 (en) * 2003-04-04 2005-05-03 Carrier Corporation Compressor protection from liquid hazards
CN1798946B (zh) * 2003-04-04 2010-05-26 开利公司 用于保护空调系统中的容积式压缩机的装置及方法
US8342811B2 (en) 2003-05-22 2013-01-01 Whirlpool S.A. Sensor assembly, a fluid pump and a cooler
JP2007513321A (ja) * 2003-05-22 2007-05-24 ファールプール・ソシエダッド・アノニマ センサアッセンブリ,流体ポンプ及び冷却器
US20070177984A1 (en) * 2003-05-22 2007-08-02 Egidio Berwanger Sensor assembly, a fluid pump and a cooler
JP4773353B2 (ja) * 2003-05-22 2011-09-14 ファールプール・ソシエダッド・アノニマ センサアッセンブリ,流体ポンプ及び冷却器
WO2004104419A1 (en) * 2003-05-22 2004-12-02 Empresa Brasileira De Compressores S.A. Embraco A sensor assembly, a fluid pump and a cooler
KR101067986B1 (ko) 2003-05-22 2011-09-26 월풀 에쎄.아. 센서 어셈블리, 유체펌프 및 냉각기
WO2005066557A1 (en) * 2003-12-30 2005-07-21 Intel Corporation Method and apparatus for two-phase start-up operation
US8333569B2 (en) 2003-12-30 2012-12-18 Intel Corporation Method and apparatus for two-phase start-up operation
US20050147500A1 (en) * 2003-12-30 2005-07-07 Ioan Sauciuc Method and apparatus for two-phase start-up operation
US8021125B2 (en) * 2004-07-22 2011-09-20 Panasonic Corporation Hermetic compressor
US20060018763A1 (en) * 2004-07-22 2006-01-26 Akio Uratani Hermetic compressor
US20120257990A1 (en) * 2009-12-29 2012-10-11 Erikson Klas Goeran Control of subsea compressors
US9382921B2 (en) * 2009-12-29 2016-07-05 Aker Subsea As Control of subsea compressors
WO2016113903A1 (ja) * 2015-01-16 2016-07-21 三菱電機株式会社 圧縮機
JPWO2016113903A1 (ja) * 2015-01-16 2017-06-08 三菱電機株式会社 圧縮機
CN108374783A (zh) * 2017-01-31 2018-08-07 泰肯贸易股份公司 通过吸液进行吸入的方法和吸液装置
CN108374783B (zh) * 2017-01-31 2021-10-29 帝肯贸易股份公司 通过吸液进行吸入的方法和吸液装置
US20190264973A1 (en) * 2018-02-26 2019-08-29 Ronald Koelsch Zone isolation control system for transport refrigeration units
US20210340967A1 (en) * 2018-11-08 2021-11-04 Panasonic Appliances Regrigeration Devices Singapore Refrigerant compressor and refrigeration apparatus using the same
US12072127B2 (en) * 2021-06-17 2024-08-27 Carrier Corporation Refrigeration system and oil recovery method for the same

Also Published As

Publication number Publication date
IT976751B (it) 1974-09-10
DE2300377A1 (de) 1973-07-12
GB1406793A (en) 1975-09-17
NL7300202A (it) 1973-07-10
FR2167786B1 (it) 1976-04-09
CA990960A (en) 1976-06-15
FR2167786A1 (it) 1973-08-24

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