US3688515A

US3688515A - Method and apparatus for removing water and noncondensible gases from certain refrigerants

Info

Publication number: US3688515A
Application number: US157904A
Authority: US
Inventors: William J Lavigne Jr
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 1971-06-29
Filing date: 1971-06-29
Publication date: 1972-09-05
Anticipated expiration: 1989-09-05
Also published as: JPS506656B1

Abstract

The invention is directed to a system for removing water and noncondensible gases from a refrigerant used in a refrigeration system, which refrigerant has the property of supporting more water in the liquid phase than in the vapor phase. Liquid refrigerant is maintained at a level in a chamber and is heated to drive off the refrigerant vapor. As the liquid refrigerant in the chamber vaporizes, the water content increases until the refrigerant is saturated with water. The water being less dense than the refrigerant, it will collect on the surface of the refrigerant and can be conveniently drained off. The liquid refrigerant is preferably heated by hot gas refrigerant taken from the high side of the system and after passing through a heating coil in the chamber, it is passed to a second chamber in which the vapor of the refrigerant is condensed by the liquid refrigerant flowing to the first chamber. The noncondensible gases are vented from the second chamber in conventional manner.

Description

ilnited States Patent Lavigne, Jr.

[ Sept.5,1972

[54] METHOD AND APPARATUS FOR REMOVING WATER AND NONCONDENSIBLE GASES FROM CERTAIN REFRIGERANTS [72] Inventor: William J. Lavigne, Jr., Fayetteville,

[73] Assignee: Carrier Corporation, Syracuse,

[22] Filed: June 29, 1971 [21] Appl. No.: 157,904

[52] US. Cl. ..62/85, 62/474, 62/475 [51] Int. Cl ..F25b 47/00 [58] Field of Search ..62/85, 195, 474, 475

[56] References Cited UNITED STATES PATENTS 1,889,191 11/1932 Bauman ..62/195 2,062,697 12/1936 Burhler, Jr ..62/85 2,202,010 5/1940 Kondolf ..62/475 3,357,197 12/1967 Mossengale ..62/195 Primary Examiner-William J. Wye Attorney-Harry G. Martin, Jr. et al.

[57] ABSTRACT The invention is directed to a system for removing water and noncondensible gases from a refrigerant used in a refrigeration system, which refrigerant has the property of supporting more water in the liquid phase than in the vapor phase. Liquid refrigerant is maintained at a level in a chamber and is heated to drive off the refrigerant vapor. As the liquid refrigerant in the chamber vaporizes, the water content increases until the refrigerant is saturated with water. The water being less dense than the refrigerant, it will collect on the surface of the refrigerant and can be conveniently drained off. The liquid refrigerant is preferably heated by hot gas refrigerant taken from the high side of the system and after passing through a heating coil in the chamber, it is passed to a second chamber in which the vapor of the refrigerant is condensed by the liquid refrigerant flowing to the first chamber. The noncondensible gases are vented from the second chamber in conventional manner.

9 Claims, 6 Drawing Figures PATENTEDsEP 5 I972 3.688.515

SHEET 1 BF 2 FIG. 2

INVENTOR. WILLIAM J. LAVIGNE JR.

65 ATTORNEY SHEET 2 IIF 2 FIG. 4

INV EN TOR. WILLIAM J. LA IGNE JR.

ATTORNEY BACKGROUND OF THE INVENTION Purge arrangements for refrigeration systems have been in use for a substantial period of years. They are all based on the refrigerant property that the vapor phase will support more water in solution than the liquid phase. Briefly stated, in such systems the refrigerant vapor is passed to a condensing means which liquifies the refrigerant which is passed to a separation chamber. The noncondensible gases are collected in the top of the chamber and are vented therefrom. The water in the mixture, being lighter than the refrigerant, will rise to the surface of the refrigerant and flows over a weir means to a water collection sump from which it is drained through a valve.

That arrangement works satisfactorily with refrigerants that have the property of supporting more water in the vapor phase than in the liquid phase. However, that arrangement will not function as a means for dehydration of systems using a refrigerant in which its liquid phase contains much more water than the vapor phase. An example of a refrigerant which has the characteristic of supporting much more water in the liquid phase than in the vapor phase is the refrigerant designated as R22 by the American Society of Heating, Refrigerating and Air Conditioning Engineers. The technical designation of that refrigerant is mononochlorodifluoromethane.

This invention has as an object a system embodying apparatus of simple structural arrangement, and which functions to efficiently separate both water and noncondensible gases from a refrigerant of the type referred to. The invention is particularly efficient in operation and does not require external heating means or separate compressing apparatus.

SUMMARY OF THE INVENTION The liquid refrigerant is vaporized by being heated in a chamber. The refrigerant vapor is passed to the cooler or the evaporator of the refrigeration system. The liquid refrigerant is heated by passing hot refrigerant vapor from the high side of the system, as the vapor area of the condenser, through a coil positioned in the chamber. In this portion of the method, the water content in the liquid refrigerant increases to saturation, with the result that the water collects on the top of the liquid refrigerant and can be drained from the chamber.

A second chamber contains a coil through which the liquid refrigerant from the refrigeration system is passed on its way to the first chamber. The coil in the first chamber has an outlet extending into the second chamber whereby any refrigerant vapor discharged from the first coil is condensed in the second chamber, by contact with the liquid refrigerant coil therein. However, as will be obvious, the noncondensible gases will collect in the upper part of the second chamber from which they are vented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in elevation with parts broken away of apparatus embodying my invention.

FIG. 2 is a top plane view of the structure shown in FIG. 1.

FIG. 3 is an enlarged cross sectional view of the upper chamber taken on a line corresponding to line 3-3, FIG. 5.

FIG. 4 is a vertical sectional view of the upper chamber and contiguous portion of the lower chamber, the view being taken on line 44, FIG. 2.

FIG. 5 is a vertical sectional view taken on line 5-5 FIG. 2 and,

FIG. 6 is a schematic illustration showing the purge apparatus connected to the refrigeration system.

DESCRIPTION OF THE PREFERRED EMBODIMENT Apparatus suitable for the practice of my invention, and as shown in the drawings, consists of a lower chamber 18 formed by a cylindrical casing 20, to the upper end of which is attached a circular plate 21. An annular flange member 23 is fixed to the lower end of the casing. The plate 21 and flange 23 are attached to the casing 20 as by welding.

A second chamber 24 is formed by a cylindrical casing 25 mounted on the plate 21 and fixed thereto as by welding. A top closure plate 27 is fixed to the upper end of the casing 25. The lower chamber is completed by a bottom disk 30 fixed to the flange 23 as by bolts 31, see FIG. 1.

A coil 32 is mounted in the upper portion of the lower chamber, the coil having an inlet 33 extending through the casing 20 and an outlet 35 extending through the plate 21 into an upper chamber 24. The outlet 35 is sealed in the plate 21. A coil 37 is mounted in the upper chamber and has an inlet 38 extending through the top closure 27 and sealed therein. The coil 37 has an outlet 40 extending through the plate 21 for discharge into the lower chamber.

The inlet 33 to coil 32 is connected to the liquid refrigerant supply in the evaporator 45 of the refrigeration system, see FIG. 6. The liquid refrigerant is metered through a line 46 from the condenser to maintain a level of refrigerant in the evaporator as indicated by the line 50. The liquid refrigerant is taken from the bottom of the evaporator through the line 33 to coil 32. Accordingly, the level of liquid refrigerant is maintained approximately at the line 50 in the upper chamber 24 by gravity flow. This places the level of the liquid refrigerant in the upper chamber substantially at the upper end of the coil 37.

The inlet 38 to coil 37 communicates with the vapor area of the condenser 47 to establish a flow of hot refrigerant vapor through the coil 37. With this arrangement, the liquid refrigerant discharged from coil 32 into the upper chamber is vaporized by the heating coil 37. The refrigerant vapor passes from the upper chamber through a line 53 to the vapor area of the evaporator 45. Line 53 is connected to a valve 55 mounted on plate 27. As the refrigerant in the upper chamber vaporizes, the water content thereof increases until the liquid refrigerant is saturated with water, and thereupon free water will collect on the surface of the refrigerant where it can be observed through a sight glass 57 mounted in a hub 58 fixed in the side wall of casing 25, see FIGS. 1, 2 and 5. The water is drained from the upper chamber by a valve 60 attached to a hub 61 fixed to the casing 25.

Accordingly, the liquid refrigerant is vaporized for the separation of water therefrom by being heated by the hot refrigerant vapor passed from the condenser of the refrigeration system through the coil 37.

During passage of the hot refrigerant vapor through the coil 37, it is to a greater or less extent condensed by heat transfer to the liquid refrigerant discharged through the tube 35. The vapor and condensed vapor in coil 37 are discharged through the outlet into the lower chamber, the liquid refrigerant dropping to the bottom of the lower chamber, and the uncondensed vapor passes around the lower edge of a cylindrical baffle 63 which is secured to the plate 21 and depends therefrom within the coil 32. The refrigerant vapor is condensed by contact with the coil 32 through which the cold liquid refrigerant is passing. As the refrigerant dispensed from coil 37 is condensed and collected in the lower chamber, it is returned to the evaporator through a conduit connected to a valve 67 operated by a float 68, see FIG. 1. The casing 20 is also provided with a hub 70 in which is mounted a sight glass 71 by means of which the presence of liquid refrigerant in the lower chamber can be ascertained.

Pressure in the lower chamber is established by the heat transfer and mass flow rates. Any noncondensibles, such as air, in the lower chamber will not be condensed and as it collects in the lower chamber, it blankets the coil 32 retarding the condensing of the refrigerant vapor discharged from coil 37 and increasing the pressure in the chamber. A pressure gauge 75 is provided for indicating such pressure. The air or other noncondensible gas collected in the upper portion of the lower chamber may be vented by a manually operated valve 77 attached to a hub 78. It will be apparent that the noncondensible gas may be vented automatically in a conventional manner by a normally closed solenoid valve operated by a differential pressure switch connected between the lower chamber and the condenser 47.

The baffle 63 serves to prevent the direct passage of refrigerant vapor from the discharge 40 of coil 37 to the upper portion of the lower chamber without being condensed by the coil 32. There is also a v-shaped baffle 80 arranged in the upper chamber. Referring to FIGS. 3 and 4, it will be observed that the coil 37 is arranged in the upper chamber eccentrically thereof, and the baffle plates 80 are arranged intermediate the coil 37 and the casing 25. The upper edge 81 of the baffle 80 terminates in a plane located at the top of the coil 37, see FIGS. 4 and 5. The baffle 80 is perforated and serves to prevent the direct passage of liquid refrigerant through the water drain valve 60. That is, the baffle permits the gradual passage of liquid into the area between the baffle and the side of the casing 25. In this area, the liquid is quiescent, permitting the water of the saturated solution to rise and collect in the upper portion of the area between the baffle and the casing 25 for discharge by the valve 60. There is a baffle 83 fixed in the casing 25 upwardly from the coil 37. The baffle has a linear edge 84 spaced from the side wall of the casing and extending in cordal relation thereto. The baffle 83 serves for the passage of refrigerant vapor only through the outlet 53.

The inlet line 38 is provided with an orifice 85 for metering the flow of vapor refrigerant to the coil 37.

A valve 86 is connected in the inlet line 38 and a valve 87 is connected in the inlet line 33 to coil 32. The

valves

55, 86 and 87 serve to isolate the purge apparatus from the refrigeration system to permit removal of the apparatus for servicing. A pressure relief valve 90 is mounted in the plate 27 and a pressure relief valve 91 is mounted in the plate 21.

The apparatus in the upper chamber 24 functions to effect separation of water from the refrigerant. This function is accomplished by the passage of hot refrigerant vapor through the coil 37 to expel the refrigerant vapor from the liquid refrigerant and the liquid refrigerant so treated serves to condense the refrigerant vapor in the lower chamber for the collection and venting of noncondensible gases. It will be apparent that the liquid refrigerant in the upper chamber 24 could be heated by other means, as an electric heater or steam passed through the coil 37. However, the arrangement disclosed herein is particularly efficient in that the hot refrigerant vapor is available in the condenser or high side of the refrigeration system. And, after it has served its purpose of boiling off the refrigerant vapor from the liquid refrigerant in chamber 24, it is condensed by the liquid refrigerant passing through the coil 32. Accordingly, the apparatus does not require any additional or separate source of heat for its operation. The collection of noncondensibles in the upper portion of the casing 20 establishes sufficient pressure to effect passage of the liquid refrigerant through the float control valve 67 for return to the evaporator 45.

I claim:

1. A method of removing water and noncondensible gases from a refrigerant used in a refrigeration system, the refrigerant having the property of supporting more water in its liquid phase than in the vapor phase, comprising the steps of maintaining a supply of the refrigerant in the liquid phase in a chamber, increasing the water content of the refrigerant to saturation by the application of heat to the refrigerant, removing free water from the surface of the refrigerant, condensing the refrigerant in the vapor phase in a second chamber for collection of non-condensible gases in the second chamber and venting the noncondensible gases from the second chamber.

2. Apparatus for removing water from refrigerant in a refrigeration system, the refrigerant having the property of supporting more water in its liquid phase than in the vapor phase, comprising passage means for conducting liquid refrigerant from the refrigeration system to a chamber and maintaining a supply of said refrigerant therein, refrigerant heating means for driving refrigerant vapor from said liquid refrigerant in said chamber to render the refrigerant therein water saturated for the collection of free water on the surface of said liquid refrigerant, means for returning said refrigerant vapor from said chamber to the refrigeration system and drain means for draining the collected water from said chamber.

3. Apparatus for removing water and noncondensible gases from a refrigerant used in a refrigeration system, the refrigerant having the property of support ing more water in its liquid phase than in the vapor phase, said apparatus comprising first and second chambers, a first passage means for conducting liquid refrigerant containing water from said system to said first chamber and maintaining a supply of predetermined volume of said refrigerant in said chamber, said predetermined volume being less than the volume of said chamber, heating means for heating said liquid refrigerant in said first chamber to drive refrigerant vapor therefrom to raise the water content of said refrigerant to saturation for the separation of water and the collection thereof on the surface of said supply, water drain means for draining the collected water from said first chamber, a second passage means operable to supply refrigerant vapor from said system to said second chamber, condensing means in said second chamber for condensing the refrigerant vapor therein and the separation of noncondensible gases from said refrigerant, a liquidrefrigerant metering valve in the lower area of said second chamber and operable to pass liquid refrigerant therefrom to the refrigeration system, and venting means for removing noncondensible gases from the upper area of said second chamber.

4. Apparatus as set forth in claim 3, wherein said heating means includes a heat exchanging coil mounted in said first chamber and forming a part of said second passage means.

5. Apparatus as set forth in claim 3, wherein said condensing means includes a heat exchanging coil mounted in said second chamber and forming a part of said first passage means.

6. Apparatus as set forth in claim 3, wherein said first passage means includes a heat exchanging coil mounted in said first chamber and having an inlet communicating with the vapor area of the condenser of the refrigeration system and having an outlet communicating with said second chamber.

7. Apparatus as set forth in claim 3, wherein said condensing means includes a heat exchanging coil mounted in said second chamber, said coil having an inlet connected to the evaporator of the refrigeration system in the liquid refrigerant area thereof and having an outlet extending into said first chamber.

8. Apparatus as set forth in claim 3, wherein said first chamber includes a casing, said heating means consists of a heat exchanging coil mounted in said first chamber and a vertically disposed perforated baffle mounted intermediate said coil and said water drain means.

9. Apparatus as set forth in claim 3, wherein said second chamber consists of a casing having bottom and top walls, said condensing means includes a condensing coil, a tubular baffle fixed to said casing top wall and depending therefrom within said condensing coil, said second passage means having an outlet arranged to discharge refrigerant vapor within said baffle, the lower edge of said baffle terminating in upwardly spaced relation to the bottom wall of said casing.

Claims

1. A method of removing water and noncondensible gases from a refrigerant used in a refrigeration system, the refrigerant having the property of supporting more water in its liquid phase than in the vapor phase, comprising the steps of maintaining a supply of the refrigerant in the liquid phase in a chamber, increasing the water content of the refrigerant to saturation by the application of heat to the refrigerant, removing free water from the surface of the refrigerant, condensing the refrigerant in the vapor phase in a second chamber for collection of noncondensible gases in the second chamber and venting the noncondensible gases from the second chamber.

3. Apparatus for removing water and noncondensible gases from a refrigerant used in a refrigeration system, the refrigerant having the property of supporting more water in its liquid phase than in the vapor phase, said apparatus comprising first and second chambers, a first passage means for conducting liquid refrigerant containing water from said system to said first chamber and maintaining a supply of predetermined volume of said refrigerant in said chamber, said predetermined volume being less than the volume of said chamber, heating means for heating said liquid refrigerant in said first chamber to drive refrigerant vapor therefrom to raise the water content of said refrigerant to saturation for the separation of water and the collection thereof on the surface of said supply, water drain means for draining the collected water from said first chamber, a second passage means operable to supply refrigerant vapor from said system to said second chamber, condensing means in said second chamber for condensing the refrigerant vapor therein and the separation of noncondensible gases from said refrigerant, a liquid refrigerant metering valve in the lower area of said second chamber and operable to pass liquid refrigerant therefrom to the refrigeration system, and venting means for removing noncondensible gases from the upper area of said second chamber.