US3145544A

US3145544A - Refrigeration system impurity purge means

Info

Publication number: US3145544A
Application number: US150802A
Authority: US
Inventors: Peter A Weller
Original assignee: American Radiator and Standard Sanitary Corp
Current assignee: American Radiator and Standard Sanitary Corp
Priority date: 1961-11-07
Filing date: 1961-11-07
Publication date: 1964-08-25
Anticipated expiration: 1981-08-25
Also published as: CH427863A; GB970620A; AT244368B

Description

Aug. 25, 1964 P. A. WELLER 3,145,544

REFRIGERATION SYSTEM IMPURITY PURGE MEANS Filed Nov. 7, 1961 2 Sheets-Sheet 2 iVAPORA FIE EI 7 INVENTOR. Fame 4 Mum BY Mid e-24,

Patented-Aug. 25, 1964 3,145,544 REFRIGERATION SYSTEM IMPURITY PURGE'MEANS Peter A. Weller, Farmington, Mich., assignor to American Radiator & Standard Sanitary Corporation, New York, N.Y., a corporation of Delaware Filed Nov. 7, 1961, Ser. No. 150,842 11 Claims. (Cl. 62-195) This invention relates to mechanical refrigeration systems, and particularly to mechanisms for purging said systems of non-condensable gases such as air and foreign liquid impurities such as water.

One object of the invention is to provide a refrigeration system purging apparatus which operates automatically without attention by the operator.

A further object of the invention is to provide a refrigeration system purge apparatus when can be operated when the refrigeration system is not running.

A still further object of the invention is to provide a refrigeration system purge apparatus which removes both liquid and gaseous impurities.

Another object of the invention is to provide a refrigeration system purge apparatus which can be utilized in various different systems without change, modification or redesign of the system.

An additional object is to provide a purge apparatus which can be used on sub-atmospheric refrigeration systerns.

Other objects of this invention will appear from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

FIGURE 1 is a diagrammatic view of a refrigeration system having one embodiment of the invention incorp rated therein;

FIG. 2 is a fragmentary diagrammatic view illustrating a modification of the FIG. 1 embodiment;

FIG. 3 is another fragmentary diagrammatic view illustrating a further modification of the FIG. 1 embodiment;

FIG. 4 is a fragmentary diagrammatic view illustrating an arrangement which incorporates features of the FIG. 2 and FIG. 3 embodiment;

FIG. 5 is a diagrammatic view of a refrigeration system having a further embodiment of the invention incorporated therewith; and

FIG. 6 is a fragmentary diagrammatic view of a modified form of the invention embodiment shown in FIG. 5.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring to the drawings, particularly FIG. 1, there is shown therein a mechanical refrigeration system including a refrigerant compressor 10, a high pressure gaseous refrigerant line 12, a refrigerant condenser 14 of the tube-shell type, a conventional refrigerant-restricting float valve means 16, a liquid refrigerant line 18, a refrigerant evaporator 20 of the tube-shell type, and a low pressure or suction line 22. The refrigeration system as above described is a conventional system usually constructed in capacities upwards of fifty tons, and the invention is concerned therewith only to the extent that a novel refrigerant impurity-removing mechanism is utilized therewith.

As shown in FIG. 1, the impurity-removing apparatus includes an upright heat exchange shell or chamber means 24 connected to condenser 14 by means of a small refrig erant line 26. A fixed or variable orifice restriction means 28 is preferably provided in line 26 so that the pressure of the refrigerant in shell 24 is somewhat less than condenser pressure. Arranged within the upright shell 24 is a finned heat exchange coil 30, positioned in such a way that the coil surface completely occupies the effective shell cross section and is disposed along the length of the shell. In the embodiment shown in the fins 32 of coil 30 fit tightly between a core 34 andthe inner surface of shell 24 so that upwardly flowing fluid must traverse the fin surfaces before reaching outlet conduit 36.

Heat exchange coil 30 receives its supply of liquid refrigerant from a refrigerant line 38 which connects with the high side of float valve 16. After flowing through coil 30 the refrigerant is returned to the system via a line 40. Line 40 preferably discharges into the system evaporator above its normal liquid level 41 to minimize back pressure effects. During purging operations the temperature of coil 30 is appreciably below the condensing temperature in condenser 14. Thus, refrigerant in purge condenser shell 24 condenses, lowering its pressure and drawing refrigerant vapor and non-condensable gases from condenser 14. This flow of vapor through restriction 28 maintains the ressure in purge condenser shell 24 below the pressure in condenser 14 as long as condensing continues in the purge condenser. The size and temperature of coil 30 determine the rate of condensation and thereby the rate of flow through restriction 28. Since refrigerant vapor enters the bottom of purge condenser 24 the flow of vapor within the purge condenser is from bottom-to-top. Because of this and the fact that the non-condensable gases are lighter than the refrigerant vapor, the non-condensables accumulate in the top of the purge condenser 24. As they accumulate, more and more of coil 30 becomes blanketed, reducing the coil surface available for condensing refrigerant vapor. As this occurs the rate of flow of vapor through restriction 28 re duces, resulting in a rising pressure within purge condenser 24. (Obviously if there were no means for releasing gas from purge condenser 24 and there was no condensation at all, the purge condenser 24 pressure would be equal to condenser 14 pressure.)

A solenoid valve 44 is located in line 36 which extends from the top of purge condenser 24. p The valve is normally closed for trapping the non-condensables and allowing .them to accumulate in the top of purge condenser 24. A pressure switch 50 is connected to the purge condenser 24 and is responsive to the pressure therein such that when the pressure on rising due to the accumulation of non-condensables reaches a preset value, the switch 50 operates to open solenoid valve 44 for releasing the accumulated non-condensable gases to the atmosphere. As soon as the pressure in purge condenser 24 drops to another preset value, usually slightly below the preset pressure at which the switch closes, the switch 50 contacts open to close solenoid valve 44. Due to the location of the vapor inlet at the bottom and the non-condensable outlet at the top of purge condenser 24, and due to the construction of coil 30, no vapor can go from the inlet to the outlet without passing directly over the cold coil 32 surfaces and scrubbing the lower coil surfaces clean of non-condensables with the natural gravitational assistance of the difference in density, thereby assuring a minimum of refrigerant vapor mixing with the non-condensables and being subsequently lost during blowoif.

Referring now to the liquid refrigerant which forms in the lower portion of shell 24, there is provided a liquid line 52 which empties into the upper portion of a liquid impurity-separating tank 54 having a pair of vertical par- 'tition's 56 and 58'for defining a first chamber 60 and a "second chamber '62. A standpipe 64 is located within chamber 60, with the upper end thereof located slightly above the upper edge of partition 58. During operation of'the mechanism, foreign liquid impurities such as water "collect in-chamberoll as a top layer as on the mass of liquid refrigerant designated by numeral 68. Overflow of liquid refrigerant from chamber 60 takes place past the'upper edge of partition 53 and into chamber 62 which contains a conventional valve '70 operated by the float 72. Since the pressure in tank 54 is above evaporator pressure the liquid released by valve 74 is able to flow to the evaporator 20 via a liquid line 74. In operation of "the-FIG. 1 system, foreign liquid impurities are allowed to build up as a liquid layer 66, with removal of the liquid being accomplished by the periodic opening of a manual valve '76. As before noted, non-condensables are exhausted from'the system via line 36.

Referring to FIG. 2, there is shown a purge mechanism which in many respects is similar to that employed in theFIG. l arrangement, the only essential difference being "that'in the FIG. 2 arrangement line 36 is provided with 'an electrically driven fluid pump 73. This enables the purge mechanism to be utilized with refrigeration systems which operate at sub-atmospheric pressures. It will be seen that during operation both the pump and normally closed solenoid valve 44 are under the control of pressure switch 50; as a result, when the absolute pressure 'in the upper portion of shell 24 reaches a predetermined value as sensed by switch the pump becomes effective to exhaust the non-condensables from the shell. When the pressure drops, valve 44 closes against further escape of the gas.

Referring to FIG. 3, there is shown a purge mechanism which provides for automatic exhaustion of liquid impurities from standpipe 64. To accomplish this action the mechanism is equipped with a liquid collection chamber "3% having connection with a gas line 82. and a liquid standpip'e line 64a. A conventional fioat valve 84 is provided between pipe 64 and line 64a to permit liquid flow from tarik'54'to chamber 89 but to prevent reverse fiow from chamber'Stl to the'tank. The discharge line 86 for chamber8tl is provided with a solenoid valve 44a suitably controlled by pressure switch 50.

In operation of the FIG. 3 mechanism, water from standpipe line 64a is permitted to collect in chamber 39 by gravity action. Periodically valve 44a opens by the action of switch 50, whereupon the gas pressure in line 82 becomes effective to flush the collected water from chamber 80 out through discharge line 85. During'the times when the water is being exhausted from chamber 81) float valve 84 prevents refrigerant from being drawn out of the system via pipe 64.

Referring to FIG. 4, there is shown a purge mechanism which includes the sub-atmospheric feature of the FIG. 2 mechanism and the automatic water exhaustion feature .of the FIG. 3 mechanism. The operation of the FIG. 4 mechanism is believed apparent without further description.

The arrangement of FIG. 5 includes two non-condens able purge mechanisms, one of which may operate when the refrigerant system is running, and the other of which may operate when the refrigerant system is idle. This other standby purge mechanism would in most cases be utilized preparatory to the system being put into use after extended periods of idleness.

As-shown in the drawings the standby purge mechanism comprises an upright shell 124 having a central core 134 and a finned heat exchange coil 130 snugly disposed in the annular space between the core and the shell inner surface. The inlet and

outlet tubes

132 and 136 for the coil may be connected to a conventional valved cold watersystem (not shown) for its supply of heat exchange fluid.

Shell124 may be supplied with system refrigerant via a 78 and line 125. In order for line 36 to receive a supply of refrigerant solenoid valve 44 must be open; accordingly there is preferably provided a manual switch 127 for holding valve 44 open during the time the standby unit is operating. The motive power for flowing the refrigerant through line 36 is supplied by pump 7 8 Shell 124 returns refrigerant to the system via a conduit defined by line 129 and the lower portion of line 52. During operation of the standby mechanism

manual valves

131 and 133 are closed, manual valve 135 is open, and the system compressor ill is of course idle, with no refrigerant flow through the coil in shell 24. The general operation involves a flow of gaseous refrigerant from line 26, upwardly through the inactive shell 24, line '36, pump '78, line and into shell 124. The pressure of non-condensables builds in the upper portion of shell "124, while the refrigerant is being condensed by the cold 24 becomes effective to accumulate non-condensables and periodically discharge same through manual valve 133, which is as stated open. Tank'54 serves-to remove water from the refrigerant both during standby operation and during normal running of the system.

The design of the FIG. 5 system permits operation of both purging units during normal running of the system if desired. Thus valve 133 can be closed and

valves

131 and 135 opened during normal run operations. Under these circumstances the flow of cold water through coil produces the final separation of refrigerant anclnoncondensables, while the flow of system refrigerant through coil 39 (in shell 24) produces a preliminary separation of refrigerant from the non-condensables. Pump 78 would preferably be placed under the control of pressure switch 59, as in the arrangement of FIGS. 2 and 4. Inclusion of pump 78 permits the FIG. 5 mechanism to be used on sub-atmospheric refrigerating systems.

Referring to FIG. 6, there is shown a purge mechanism which provides the standby feature of the FIG. 5 mechanism and the automatic Water exhaustion feature of the FIG. 3 and 4 mechanisms. During standby operation refrigerant from line 26 flows upwardly through inactive shell 24, solenoid valve 44, purnp'78, line 82, branch line 1125, gas purge shell 124, line 129, the lower portion of line 52, and into water separator tank 54. At such time switch 127 is closed, manual valves 131 and '152 are closed, and manual valves 154 and are open. Power for flowing the refrigerant is provided by pump '78.

During normal running of the

systemvalves

131 and 152 are open, and

valves

135 and 154 are closed. Shell 124 is deprived of refrigerant, and gas purging takes place within shell 24. Water exhaustion is accomplished with the gas pressure in line 82 as previously described in connection with the FIG. 4 embodiment. The FIG. 6 mechanism includes a pump 78, and it therefore can be utilized with sub-atmospheric systems. v

The design of the FIG. 6 system permits operation of both purging units during normal run periods if detank 54 and

shells

24 and 124 relative to the sizes of the system condenser and evaporator are exaggerated, and that in the actual physical form the

system devices

14 and 20 would be many times larger than the purge de vices. The invention is recognized to be capable of some modification from the various forms thereof shown in the drawings without departing from the spirit of the invention as setrforth in the accompanying claims.

I claim:

1. In combination, a mechanical refrigeration system; means connected with said system for purging same of non-condensable gases; means connected with said system for separating water from the system refrigerant; means for directing high pressure non-condensable gas accumulations against the separated water to expel same from the water separator means without exposing the refrigeration system to the atmosphere; and an electrically-operated means controlled by the pressure of the non-condensable gases to control the expelling operation.

2. In combination, a mechanical refrigeration system including a refrigerant compressor, condenser and evaporator; means for purging said system of non-condensable gases including a heat exchange unit having an inlet to receive gaseous refrigerant from the system, having a first outlet for discharging condensed refrigerant therethrough, and having a second outlet for discharging non-condensable gases; means for circulating coolant through said heat exchange unit to condense refrigerant flowing from the aforementioned inlet so that non-condensable gases collect in the heat exchange unit adjacent the second outlet; means for separating foreign liquid impurities from the refrigerant which is discharged from the first outlet; and means for intermittently expelling the separated foreign liquid impurities and non-condensable gases without exposing the refrigeration system to the atmosphere, including a chamber connected with the aforementioned second outlet and foreign liquid separating means, an electrically-operated means for controlling fluid flow from the chamber, and switch means operated by gas pressure in the heat exchange unit for controlling the electricallyoperated means so that when the pressure of the noncondensable gases is above a predetermined value the gases and foreign liquid are expelled from the chamber.

3. The combination of claim 2 wherein the electricallyoperated means comprises an electrically energized fluid pump.

4. The combination of claim 2 wherein the electrically operated means comprises a solenoid valve.

5. In combination, a mechanical refrigeration system including a refrigerant compressor, condenser, evaporator shell having a normal liquid level therein, and float valve between the condenser and evaporator shell; means for purging said system of non-condensable gases including an upright heat exchange unit having an inlet in its lower portion to receive gaseous refrigerant from the system, having a first outlet in its lower portion for discharging condensed refrigerant, and having a second outlet in its upper portion for discharging non-condensable gases; means for circulating coolant through said heat exchange unit to condense refrigerant flowing upwardly from the aforementioned inlet so that non-condensable gases collect in the upper portion of the heat exchange unit adjacent the second outlet; said coolant circulating means comprising a refrigerant evaporator section disposed in the heat exchange unit, a liquid refrigerant line extending from a point located in the system between the condenser and float valve to the inlet of the evaporator section, and a discharge line extending from the evaporator section to a point in the evaporator shell located above the liquid level therein; means for separating foreign liquid from the refrigerant, including a tank structure connected to receive liquid from the aforementioned first outlet, partition means within the tank structure defining a first chamber for containing an upper foreign liquid layer and a lower refrigerant layer and a second liquid refrigerant chamber for returning refrigerant to the system, and a standpipe having a portion thereof disposed within the first chamber to skim off foreign liquid therefrom; means for intermittently expelling the skimmed-off liquid and non-condensable gases without exposing the refrigeration system to the atmosphere, including a third chamber having a portion thereof connected with the aforementioned second outlet and having a second portion thereof connected with the aforementioned standpipe, a solenoid valve openable to expel non-condensables and foreign liquid from said third chamber, and a solenoid-controlling switch operated by pressure in the upper portion of the heat exchange unit so that when the pressure of the noncondensable gases is above a predetermined value the solenoid valve is open and when the pressure of the noncondensable gases is below a predetermined value the solenoid valve is closed.

6. In combination, a mechanical refrigeration system including a refrigerant compressor, condenser and evaporator; means for purging said system of non-condensable gases when the system is running, including a first heat exchanger having an inlet to receive gaseous refrigerant from the system, a liquid outlet for discharging condensed refrigerant, and a gas outlet for discharging non-condensable gases; means for circulating system refrigerant in heat transfer relation with said heat exchanger to condense refrigerant flowing from the aforementioned inlet so that non-condensable gases collect adjacent the gas outlet; means for separating foreign liquid from the refrigerant, including a separator chamber for receiving refrigerant and liquid impurity from the liquid outlet, and means operative to skim off a layer of liquid impurity from the chamber refrigerant; means for purging the system of non-condensable gases when the system is idle, including a second heat exchanger having an inlet to receive gaseous refrigerant from the gas outlet of the first heat exchanger, a liquid outlet discharging to the aforementioned separator chamber, and a gas outlet for noncondensables; an electric valve for each gas outlet; pressure switches responsive to pressure conditions in the respective heat exchangers or automatically operating the respective electric valves; and means for operating the first heat exchanger electric valve independently of the first heat exchanger switch.

'7. In combination with a mechanical refrigeration system having a refrigerant compressor, condenser and evaporator; means for purging said system of non-condensable gases when the system is running, including a first heat exchanger having an inlet to receive gaseous refrigerant from the system, a first liquid outlet for discharging condensed refrigerant, and a first gas outlet for discharging non-condensables; means for circulating system refrigerant through said heat exchanger to condense refrigerant flowing from the aforementioned inlet so that non-condensables collect adjacent the gas outlet; means for separating foreign liquid from the refrigerant, including a separator chamber for receiving refrigerant and liquid impurity from the aforementioned liquid outlet, and means operative to remove a layer of liquid impurity from the chamber refrigerant; means for purging the system of non-condensables when the system is idle, including a second heat exchanger having an inlet to receive gaseous refrigerant from the system, a second liquid outlet discharging to the aforementioned separator chamber, and a second gas outlet for non-condensables; and valve means controlling flow through the two liquid outlets so that liquid can flow either from the first liquid outlet to the separator chamber or from the second liquid outlet to the separator chamber.

8. In combination, a mechanical refrigeration system; means connected with said system for purging same of non-condensable gases; means connected with said system for separating liquid impurities therefrom; means for causing the purged non-condensable gases to automatically expel separated liquid impurities without excomprising a collection chamber having a first inlet arranged to accept purged non-condensable gases from the purging means, having a second inlet arranged to accept separated liquid impurities from the liquid impurity sepa- .rating means, and having an outlet arranged to exhaust j gas and liquid to the atmosphere; and means between the liquid impurity separating means and said second inlet for permitting liquid to flow into the collection chamber but preventing reverse flow from the collection chamber back to the liquid impurity separating means.

9. In combination with a mechanical refrigeration system having a refrigerant compressor, condenser and evaporator; means for purging said system of non-condensable gases, including a first heat exchanger having a first inlet .to receive gaseous refrigerant and non-condensables from the system, a first liquid outlet for discharging condensed refrigerant, and a first gas outlet remote from the liquid outlet; means for circulating system refrigerant through said first heat exchanger to condense refrigerant flowing from the aforementioned inlet; second means for purging the system of noncondensables, including a second heat exchanger having an inlet to receive gaseous refrigerant .and non-condensables from the first gas outlet, a second liquid outlet for discharging condensed refrigerant, and

for discharging non-condensables to atmosphere; means for circulating non-system liquid coolant through said ,second heat exchanger to condense refrigerant flowing from the second inlet; and means for pumping gas from the first gas outlet to the second gas inlet.

10. In combination with a mechanical refrigeration system having a refrigerant compressor, condenser and evaporator; means for purging said system of non-condensables, including a first upright shell having a first inlet in its lower portion to receive gaseous refrigerant and non- .condensables from the system, a first liquid outlet in its 25 .a'second gas outlet remote from the second liquid outlet I for discharging condensed refrigerant, and a second gas outlet in its upper portion discharging to atmosphere; means for circulating non-systemtliquid coolant through the second shell, including a second finned heatexchange coil occupying substantially the entire free space between the second inlet and second gas outlet; and means for pumping gas from the first gasoutlet to the secondgas inlet.

11. In combination with a mechanical refrigeration system having a refrigerant compressor, condenser and evaporatorymeans for purging said system of non-condensables, including a first upright shell having a first inlet in its lower portion to receive, gaseous refrigerant and non-condensables from the system, a first liquid outletin its lower portion for discharging condensed refrigerant, and a first gas outlet in its upper portion; means for circulating system refrigerant through the shell to condense refrigerant flowing from the inlet, including a finnedheat exchange coil occupying substantially the entire free space between the inlet and gas outlet; second means for purging the system of non-condensables, including a second upright shell having a secondinlet in its lower portion to receive gaseous refrigerant and non-condensables from the first gas outlet, 21 second liquid outlet in its lower portion for discharging condensed refrigerant, and a second gas outlet in its upper portion discharging to atmosphere; means for circulating non-system liquid coolant through the second shell, including a second finned heat exchange coil occupying substantially the entire free space between the second inlet and second gas outlet; means for pumping gas from the-first gas outlet to the second gas inlet; means communicating with each liquid outlet for separating liquid impurities from the refrigerant discharged therethrough; and means for returning refrigerant from the separating means to the system.

References Cited in the fileof this patent UNITED STATES PATENTS 1,925,805 Holle Sept. 5, 1933 2,062,697 Buehler 'Dec. 1, 1936 2,202,010 Kondolf' May20, 1940 2,327,081 Walters Aug. 17, 1943 2,400,620 Zwickl May 21, 1946 2,450,707 Zwickl Oct. 5, 1948 2,986,894 -Endress et al June '6, 1961 2,986,905 Kocher et al June 6, 1961 3,013,404 Endress etal Dec.t.12, 196'1