US1866373A - Refrigerating apparatus - Google Patents

Description

' July 5, 1932. H. F. SMITH 1,866,373

I REFRIGERAT ING APPARATUS Filed Sept. 50. 1929" WM Q l MTTORNEY Panted duly 5, 1932 ED SAT P NT OFFICE HARRY E. SMITH, F DAYTON, OHIO, ASSIGNOR TO ERIGIDAIRE CORPORATION,.OF DAYTON, OHIO, A COBPORATIOIQ' OF DELAWARE REFBIGERATING APPARATUS Application filed September 30, 1929. Serial No. 396,230.

This invention relates to refrigerating apparatus and moreparticularly to devices for automatically controlling refrigerating systems, especially those of the intermittent absorption type.

One of the objects of the invention-is to provide an improved control apparatus which permits the refrigerating system to operateonly in response to an adequate flow 0 of cooling medium. a by Another object is to provide a control apparatus in which the existence of a vacuum is essential to operation of the refrigerating system, and to provide an improved arrangew ment for maintaining a vacuum.

More specifically, it is one of the objects of the invention to provide'an arrangement in which a dependable control of the vacuum system can be maintained even with low rates of flow of cooling medium.

Further objects and advantages of the present invention will be apparent from the following description, referencebeing had to theaccompanying drawing, wherein a 'preferred form of the present invention is clearly shown.

The single figure of the drawing is a diagrammatic representation of a refrigerating system embodying the invention.

As represented therein, the improved refrigerating system includes a generator-absorber generally designated by 50 which is automatically heated and cooled to supply refrigerant to a refrigerating element or evaporator 52 and to withdraw refrigerant from the element, which may be used to cool any suitable cabinet or compartment 54. A condenser 56 is interposed between the generator-absorber and the refrigerating element. The generator absorber 50 includes any suitable container 58 for absorbent which is connected by a refrigerant conduit 60 with the chamber 56 of the condenser which is cooled in any suitable, manner for example by water or other cooling medium flowing through a coil62. Liquefiedarofrigerant flows from the chamber 56 through a conduit 64 to the evaporator 52. lVhen the generator-absorber is heated, gaseous refrigjcrant isgiven off, and will flow to and be condensed in the coldest part of the system.. If the evaporator has previously been cooled by evaporation of refrigerant produced by an absorbing period, it will be colder than the condenser, hence refrigerant will tend to liquefy in the evaporator. In order to re-' duce the amount of condensation which can take place in the evaporator, the latter is formed as an insulated reservoir of small surface 66 having depending circulating and evaporating tubes 68 of large exposed surface which are maintained at all times filled with liquid refrigerant. Since the evaporating tubes are filled with liquid and since the reservoir is insulated, the heat of condensation of the refrigerant initially condensed will be confined to the reservoir and will speedily elevate its temperature above that of'the condenser after which all condensation will take place in the condenser. The warm liquid will remain at the top of the evaporator and will not circulate. When the generator-absorber is cooled, the refrigerant in the reservoir will be evaporated, reducing the temperature of the reservoir to that of the tubes 68, after which continued cooling of the generator-absorber will produce evaporation in the tubes which are exposed to the atmosphere to be cooled.

A closed vapor circuit is provided for the purpose of heating and cooling the generator-absorber 58. The latter is enclosed in a container 70 herein termed a vapor shell which may be filled to an upper level 72 with volatile liquid such as alcohol or ethyl chloride and which is connected to a vapor condenser 74 above the level of the vapor shell by means of a. vapor conduit 7 678 leading from the top of the vapor shell to the top of the condensing chamber, and a liquid conduit L80 leadin from the bottom of the condensing chamber 4: to a point near the bottom of the container 70. The liquid in the vapor shell is vaporized by any suitable heating device herein exemplified as a gas burner 82 placed beneath the vapor shell. When the generatorabsorber, is to be heated the burner is lighted by automatic control means hereinafter described in detail and a valve 84 is closed in a valve chamber 86 interposed be- 100 'the atmosphere.

tween the sections 76 and 7 8 of the vapor conduit. hen the burner begins to vaporize the liquid in the chamber 70, the pressure of the vapor forces the remaining liquid up through the conduit 80 filling the condensing chamber 74 and reducing the level of the liquid in the chamber 70 to a point which may be below the generator-absorber 58 and is exemplifiedby the level 88. The liquid continues to be vaporized by the burner and condensed on the'generator-absorber 58 giving upits latent heat and causing the absorbent to evolve its refrigerant.

The vapor condenser may be cooled by any suitable circulating mediumsuch as water which preferably flows continuously through a coil 90. When the generator-absorber is to'be cooled the burner is turned off and the valve 84 in the vapor conduit is opened. This permits the vapor in the vapor shell to pass into the vapor condenser and the liquid in the condenser to flow down into the container 70, again submerging the generatorabsorber to the level 72. The hot generatorabsorber vaporizes the liquid, the vapor flowing up through the conduit 7 6 to be condensed again. This vaporization and condensation of the circulating liquid cools the generatorabsorber to withdraw and absorb the refrigerant from the evaporator 52.

The invention contemplates suitable automatic control devices for cyclically heatingthe cooling water circulates continuously through both-the refrigerant condenser and the .vapor condenser since at any instant one of the other of the condensers must be cooled, and since the circulation of water through either condenser does no harm when that condenser is not functioning as such. Water may enter the system at the refrigerant condenser cooling coil 62 and flow by a. conduit 92 to the vapor condenser cooling coil 90.

In order to obtain the necessary power for actuating the control devices a jet or entrainment pump is placed in the water conduit 92. This pump includes a chamber 94 having a restriction or throat 96 into which a jet of water is discharged from an orifice 97. Connected to the chamber 94 is a suction conduit system 98 in which a vacuum is maintained by the jet pump. Connected to the conduit 98a is an expansible chamber motor 100 which is preferably formed of a bellows, the

interior of which is connected with the conduit 98a but which is otherwise sealed from The bellows may be expanded by a spring 102 when the pressureiii'n theconduit 98 is not reduced, and may be collapsed by atmospheric pressure when a vacuum exists in the conduit. The end of the bellows is attached by a pin and slot connection to a lever 104 provided with a fork 106 which-is pivotedat 108. Between the forks a portion 110 of the lever extends within the casing 86 for opening the valve 84, the lever being sealed to the casing by a flexible connection formed by a packingbellows 112 placed within the fork 106 and surrounding the portion .110 and sealed thereto. When a vacuum exists in the conduit 98, the bellows 100 collapses to close the valve 84, and when the vacuum is broken, the bellows expands to open the valve.

The pivots 108 of the forked lever 104 are mounted on a second forked lever 114,.pivoted at 116 and also surrounding the packing bellows 112. which may expand and contract with changes of pressure in the valve casing 86. The fork 114 may move up and down about the pivot 116and is urged against a stop 118 by a spring 120. The fork 114 has an arm 121 extending to the left of the pivot through which freely passes a valve stem 122 carrying a vacuum-breaking valve 124 which may co-operate with a seat 126 to close the vacuum conduit system from the atmosphere. The valve may be closed by downward movement of the arm 121 when the packing bellows collapses due to low pressure in the valve casing 86. The valve may be opened by upward movement of the arm 121 when the packing bellows expands due to high pressure. A light spring 128 is interposed beween the arm 121' and the valve stem to raise the valve away from its seat once it has been opened.

The gas burner 82 is controlled by a gas valve 130 attached to a bellows 132, similar to the bellows 100, which is also connected to the vacuum conduit system 98 and is collapsed to open the gas valve when the vacuum is produced and is expanded to close the gas valve when the vacuum is broken. The burner is lighted when the valve is open from a constantly burning pilot 134. The vacuum conduit system includes a high temperature safety conduit 136,-the end of which is normally closed by afusible plug disposed in a well in the vapor shell 7 O. This is for the purpose of breaking the vacuum to shut off the burner in case of an excessively high temperature in the vapor shell.

It will be appreciated that the rate at which refrigeration is evaporated depends on the rate of absorption by the absorber 58, which in turn depends upon the rate at which the absorber is cooled. This of course is directly dependent upon the temperature and rate of flow of cooling water. Consequently the rate at which refrigeration is produced can be controlled directly by! controlling the flow of cooling water. For! this purpose a valve casing 142 containing a throttle valve 144 is interposed in the conduit 92. This valve is actuated by a lever 146 pivoted at a stationary point 148, sealed to the casing by a packing bellows 1 50 and urged counterclockwise by the spring 152 which serves to open the valve. The maximum'opening of the valve is determined by an adjustable stop 154. The lever 146 is rotated clockwiseto throttle the water in response to the temperature of the evaporator by means of a bellows 156 which is connected to the conduit 64 by a conduit 158. The pressure of the-evaporator and consequently the pressure in the bellows 156 is a function of the temperature of the evaporator. Consequently when the evaporator has been reduced to the desired temperature the bellows 156 collapses to throttle the supply of cooling water which slows down the refrigeration rate to that required to maintain the desired temperature. If refrigeration at a greater rate is demanded the evaporator tends to become warm and its pressure is increased permitting the bellows 156 to expand somewhat and permitting the valve to open to produce absorption at a increased rate.

Preferably the throttle valve operates in the jet orifice 97, and is provided with a cylindrical jet-directing member 157 which projects thru the orifice and directs the jet of water into the throat 96.

The temperature at which the cabinet will be maintained can be adjusted by regulating the temperature at which the valve 144 will be actuated and the amount of movement of this valve. This can be accomplished by adjusting the tension of thespring 152, but.

I prefer to provide an independent cold control in the form of the separatespring 160 which may be brought intoE play when desired to resist the movement of the control lever 146 and the tension of which may be suitably adjusted by any convenient mechanism such as the cam 162 operated by the lever 164. In this manner the spring tension on the lever 146 may be simply adjusted, and

yet the normal adjustment, that is the'tension of the spring 152, will remain undise turbed when the cold control adjustment is removed.

Since the vacuum conduit system 98 is normally closed to the atmosphere when the pressure responsive devices 100 and 132 areto be actuated, the jet pump will soon exhaust the system of'air. When this condition occurs there is practically no air entrained by the jet and the surface of the jet becomes very smooth. Difiiculty is experienced in keeping a perfectly smooth jet continuouslyin contact with the wall of the throat 96 because the jet may be so attenuated, or may become so small due to low water pressure that it may not fill the orifice or throat. Also the jet may be deflected by minute particles of foreign matter or by the misalignment of the valve 144, or the water pressure may drop to a value which makes it difficult to keep the throat filled. In any of these contingencies air may leak back through the throat 96 and destroy the vacuum in the conduit system 98.

To avoid the possibility of these difficulties I provide means for admitting a limited quantity of air to the jet after the pressure in the vacuum conduit system has been reduced to the value necessary to actuate the bellows 100 and 130. 'Within the scope of this invention, the air may be introduced into the water stream before it reaches the j at pump as by aerating the water supply, but for the sake of simplicity I prefer to admit air directly to the chamber 94 around the jet. This may be accomplished by a check valve having a restricted opening 166 which may admit air to the vacuum conduit system, and hence eventually to the chamber 94, by means of the conduit 168, the orifice 166 being normally closed by a valve 17 O which is loaded to the extent necessary to maintain the valve closed until the desired low pressure is attained. The loading may be accomplished by a spring or any other suitable loading device. As illustrated for the sake of simplicity, the valve is a heavy weight the end of which.is formed into the valve proper. Preferably the valve is pointed to provide a pro jection which extends thru the opening 166 when the valve is closed for the purpose of removing any dust which may accumulate in theopening. Thus every time the burner 82 is turned off the valve 170 will drop and its point will assure that the opening 166 is clean.

The provision of the valve 170 has an additional advantage that the degree of vacuum maintained in the vacuum conduit system is just suflicient to insure operation of-the bellows. The size of the opening 166 and the weight of the valve 170 are so proportioned that air can not be admitted to the system fast enough to increase the pressure above that required to collapse the bellows, but on the other hand it prevents the production of an extremely high vacuum which might place an unnecessary strain on the bellows.

Operation of the system When the apparatus is first started the refrigerator cabinet is warm and the generatorabsorber 58 is charged with refrigerant. The bellows 156 is expanded and the rod 146 consequently moved against the stop 154 by the spring 152 to permit the maximum flow of water thru the condensing circuit. This flow produces a sufliciently low pressure in the conduit system 98 to collapse the valve bellows 100 and close the vapor valve to prevent the circulation of heating and cooling fluid. Simultaneously the gas valve bellows 132 iscollapsed to open the gas line and sup ply the burner 82 which is lighted by the pilot 134.

Any further reduction in pressure in the vacuum conduit system opens the valve 170 which prevents the production of'low pressures and insures the maintenance of the bellows 100 and 132 in collapsed condition by supplying just suflicient air to the pump chamber 94 to keep the ct sufficiently turbulent to maintain the vacuum sealed. The liquid in the generator-absorber chamber 7 now stands at the level 72 but a small quantity of this liquid is soon vaporized and the remaining liquid forced thru the liquid conduit 80 into the condenser 74 where it remains inert. After all of the refrigerant has been driven out of the generator-absorber the pressure of the heating and cooling vapor increases, until at a predetermined high pressure the packing bellows 112 on the valve operating lever 104 expands against the force of the spring 120 to raise the arm 121 a sufficient amount to compress the spring 122 to open the vacuum breaking Valve 124. Breaking the vacuum permits the two bellows 100 and 132 to expand, opening the valve 84 and closing the gas Valve 82. As soon as the vacuum valve is open thespring 128 lifts the valve from its seat in order that subsequent contraction ofthe bellows will not immediately seat valve 124 but will permit it to remain open until a predetermined low pressure in the vapor circuit has been reached, this condition representing a predetermined low temperature of the generator-absorber.

.This generator-absorber is now cooled by the circulation of fluid in the vapor circuit as has been previously described. As the cooling progresses the refrigerant evaporates in the evaporator and is absorbed in the generator-absorber. After all of the refrigerant has been taken up which the generatorabsorber can absorb the latter suddenly tends to drop in temperature to the temperature of the cooling water. This reduces the pressure in the vapor cooling circuit sufficiently'to contract the bellows 112 to close the vacuum valve 124 and initiate another generating period.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood'that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Apparatus of the character described comprising a normally closed pressure responsive actuator, means for reducing the pressure within the actuator including an orifice and means for discharging a jet of liquid into the orifice, and means for insuring continuous contact between the jet and a wall of the orifice including means responsive to a predetermined low pressure within the, actuator for admitting gas to contact with the jet.

2. Apparatus of the character described comprising a normally closed actuator responsive to a predetermined low pressure for moving a controldevice, means for reducing the pressure in the ,actuator'to a predetermined degree including an orifice and means for discharging a jet of liquid into the orifice and meansfor insuring continuous contact between the jet and the wall of the orifice including means responsive to pressures in the actuator below said predetermined pressure for bringing a gas into contact with the liquid jet. 3. Apparatus of the character described comprising a normally closed actuator responsive to a predetermined low pressure, means for reducing the pressure within the actuator including an orificeand means for discharging a jet of liquid into the orifice, and means for insuring continuous contact between the jet and a wall of the orifice including a valve responsive to a pressure below said predetermined pressure in the actuator for admitting air to the jet.

In testimony whereof I hereto aflix my signature.

. HARRY F. SMITH.

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