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Publication numberUS3677028 A
Publication typeGrant
Publication dateJul 18, 1972
Filing dateDec 1, 1970
Priority dateDec 1, 1970
Publication numberUS 3677028 A, US 3677028A, US-A-3677028, US3677028 A, US3677028A
InventorsRaymond Glendon A
Original AssigneeCarrier Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Refrigeration system
US 3677028 A
Abstract
A refrigeration system employing a plurality of evaporator circuits, the refrigerant flow to each circuit being controlled by a shut-off valve and a fixed restriction, the valve when open providing a first stage restriction to minimize the required pressure drop across the fixed restriction.
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Description  (OCR text may contain errors)

United States Patent Raymond [45] July 18, 1972 I5 1 REFRIGERATION SYSTEM 1,803,074 4/1931 Schickler 62/5l l [72] Inventor: Glendon A. Raymond, Fulton, N.Y.

. Primary Examiner-Meyer Perlin [73] Asslgnee' Carrier Corporation Syracuse Attorneyl-larry G. Martin, Jr. and J. Raymond Curtin [22] Filed: Dec. 1, 1970 [2]] Appl. No.: 94,036 [57] ABSTRACT A refrigeration system employing a plurality of evaporator cir- [52] US. Cl ..62/200, 62/205, 662275212, Quits, the refrigerant flow to each circuit being controlled y a l 51 1 Int Cl F25) 5/00 shut-off valve and a fixed restriction, the valve when open 58] Fieid 222 223 providing a first stage restriction to minimize the required 5 l 9 pressure drop across the fixed restriction.

[56] References Cited 3 Claims, 1 Drawing Figure UNITED STATES PATENTS 2/1939 Labberton "62/51 1 PATtNlEuJuu'emz 3;677'.02-8

INVENTOR. GLENDON A. RAYMOND BY KziMf ATTORNEY REFRIGERATION SYSTEM BACKGROUND OF THE INVENTION In many refrigeration systems, a plurality of evaporators or evaporator circuits may be employed with a single condensing unit. Liquid line solenoid valves may be employed to activate those evaporators or evaporator circuits that are needed to satisfy the load on the system. A restriction device such as a thermal expansion valve may be provided between the solenoid valve and the evaporator or evaporator circuit associated therewith to control the flow of refrigerant to the evaporator.

SUMMARY OF THE INVENTION This invention relates to a refrigeration system comprising a compressor, a condenser for condensing high pressure refrigerant vapor from the compressor, and a plurality of evaporator circuits for passing heat exchange medium to be cooled in heat exchange relationship with refrigerant from the condenser, the refrigerant in the evaporator circuits being heated and vaporized by the heat exchange medium. Valve means are provided for each evaporator circuit, the valve means being adapted to prevent flow of refrigerant to the evaporator circuit when the valve means is closed and to provide a first stage restriction to the flow of refrigerant to the evaporator circuit when the valve means is open. A fixed refrigerant restrictor in the refrigerant line between the valve means and the evaporator circuit associated therewith is provided to produce a second stage restriction upstream of the evaporator circuit.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic of a refrigeration system embodying the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawing, there is illustrated a refrigeration system including a compressor 3 adapted to receive low pressure refrigerant vapor from refrigerant line 5 and provide high pressure refrigerant vapor to a condenser 7 through refrigerant line 9. Fan means 11 are provided for passing a heat exchange medium, preferably ambient air, in heat exchange relation with refrigerant within the condenser 7 to condense the refrigerant. Liquid refrigerant from condenser 7 is supplied to a plurality of evaporators or evaporator circuits 13 through refrigerant line 15.

Each of the evaporator circuits 13 is provided with suitable valve means such as solenoid valves 17 and suitable fixed restriction means such as capillaries 19. The solenoid valves 17 are adapted to prevent flow of refrigerant to the evaporator circuit associated therewith when the cooling load served by the evaporator circuit is satisfied. The valves 17 are also adapted to provide a first stage refrigerant flow restriction for the evaporator circuit associated therewith when the valve is open. The capillaries 19 provide second stage refrigerant flow restrictions for the evaporator circuits associated therewith, the total restriction provided by the valves and the capillaries being selected to provide the desired superheat in the refrigerant leaving the evaporator circuits under normal operation conditions.

ln systems which have heretofor employed solenoid valves to prevent flow of refrigerant to the evaporator circuit associated therewith, a valve two or three times as large as that necessary in the disclosed system was necessary to prevent flashing or undue restriction to the flow of refrigerant. By utilizing a small valve and placing a fixed restrictor adjacent or immediately downstream from the valve, the valve may be utilized as a first stage restriction. The fixed restriction must be placed adjacent or immediately downstream from the valve to minimize pressure recovery between the valve and the fixed restriction.

By providing a first stage pressure drop through the solenoid valve of at least 50 percent of the total pressure drop through the valve and the capillary, a smaller and, therefore, more refrigerant therein, the heat exchange medium being cooled and the refrigerant being vaporized thereby. Refrigerant from the evaporator circuits is provided to an accumulator 21 through refrigerant line 23. Liquid refrigerant which may have passed through the evaporator circuits under low load conditions is collected in the lower portion of the accumulator to prevent slugs of liquid refrigerant from reaching the compressor and causing damage to the valves thereof. Refrigerant vapor from the upper portion of the accumulator passesto the compressor through refrigerant line 5 to complete the refrigeration cycle.

I claim:

1. A refrigeration system comprising a compressor;

a condenser for condensing refrigerant vapor from said compressor;

a plurality of evaporator circuits for passing heat exchange medium to be cooled in heat exchange relationship with refrigerant from said condenser, the refrigerant in the evaporator circuits being heated and vaporized thereby;

individual valve means associated with each of said evaporator circuits, each of said individual valve means being adapted to prevent flow of refrigerant to the evaporator circuit associated therewith when said valve means is closed and to provide a first stage pressure drop to restrict flow of refrigerant to the evaporator circuit associated therewith when said valve means is open; and

fixed restriction means disposed immediately downstream from each of said individual valve means to provide a second stage pressure drop to restrict flow of refrigerant to the evaporator circuit associated therewith, said individual valve means providing at least 50 percent of the pressure drop created by the combination of said individual valve means and said fixed restriction means.

2. A refrigeration system according to claim 1 wherein said refrigerant restriction means is a capillary tube.

3. A refrigeration system according to claim 2 wherein each of said individual valve means comprises a solenoid valve, the total restriction to refrigerant flow through said solenoid valve and said capillary producing the required refrigerant flow to the evaporator circuit associated herewith.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1803074 *Jun 14, 1929Apr 28, 1931Edmund E AllyneRefrigerating apparatus
US2148413 *Mar 12, 1935Feb 21, 1939Westinghouse Electric & Mfg CoRefrigerating apparatus
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3884663 *May 6, 1974May 20, 1975Funaro EttoreRefrigerator system with refrigerant expansion through capillary tubes of adjustable length
US4233818 *Jun 23, 1978Nov 18, 1980Lastinger William RHeat exchange interface apparatus
US4269042 *Sep 28, 1979May 26, 1981E. I. Du Pont De Nemours And CompanyCentrifuge refrigeration system
US4286438 *May 2, 1980Sep 1, 1981Whirlpool CorporationCondition responsive liquid line valve for refrigeration appliance
US4344299 *Aug 5, 1980Aug 17, 1982Latzer John BTransportable compartment refrigeration panel system and method of installing
US4373353 *Aug 17, 1977Feb 15, 1983Fedders CorporationRefrigerant control
US4394816 *Nov 2, 1981Jul 26, 1983Carrier CorporationHeat pump system
US4459819 *Nov 1, 1982Jul 17, 1984Emerson Electric Co.Apparatus for controlling a refrigeration system
US4550574 *Oct 19, 1984Nov 5, 1985Sexton-Espec, Inc.Refrigeration system with liquid bypass line
US4563879 *May 21, 1985Jan 14, 1986Mitsubishi Denki Kabushiki KaishaHeat pump with capillary tube-type expansion device
US6138919 *Sep 19, 1997Oct 31, 2000Pool Fact, Inc.Multi-section evaporator for use in heat pump
US6502413 *Apr 2, 2001Jan 7, 2003Carrier CorporationCombined expansion valve and fixed restriction system for refrigeration cycle
US7178362 *Jan 24, 2005Feb 20, 2007Tecumseh Products CormpanyExpansion device arrangement for vapor compression system
US8806879 *Aug 8, 2011Aug 19, 2014Danfoss A/SMethod of analysing a refrigeration system and a method of controlling a refrigeration system
US20110289948 *Aug 8, 2011Dec 1, 2011Danfoss A/Smethod of analysing a refrigeration system and a method of controlling a refrigeration system
Classifications
U.S. Classification62/200, 62/511, 62/205, 62/222
International ClassificationF25B5/00, F25B5/02
Cooperative ClassificationF25B5/02
European ClassificationF25B5/02