US2297287A - Refrigeration - Google Patents

Description

Sept. 29, 1942.

' 2 Sheets-Sheet 1 .!iiiiiiiiiiiiiiiii.iil

1 .'.'.'.i. 5 iiiiiii iiiiiiiiiiiiiii INVENTOR v 'ea yeAuBmce ATTORNEY w pghzs, 1942. P G. A BRACE I. REFRIGERATION Filed July 20, 1958" 2 Sheets-Sheet 2- //////////////////////////fl////)/// /////////fl "INVEIQTOR Geozye A. Brae 6 BY A Y ATTORNEY Patented Sept. 29, I942 REFRIGERATION George Ac Brace, 11h, alsignorto The Hoover Company, North Canton, Ohio, a corporation of Ohio Application July 20, use. Serial No. 220,191

- 25 Claims. (oi. se-s) This invention relates to the art of refrigeration and more particularly to a novel absorption refrigerating system.

According to the presen invention there is provided a refrigerating system of the absorption type which includes a pair of evaporator sections connected in parallel into an izing medium circuit and adapted to perform different flmctions. One evaporator section is adapted to be placed in heat transfer relationship with a body of water in order to freeze ice V blocks within the body of water periodically. Means are provided to permit periodic discharge of liquid refrigerant" and inert gas into the ice freezing evaporator and to discontinue such discharge of inert gas and liquid refrigerant for a period of time in order to permit previously formed ice blocks to melt free of the walls of the water container. The other evaporator section is arranged to refrigerate alow temperature refrigerating chamber.

his a further object of the invention to provide an absorption refrigerating system in which the production of ice is regulated by a control.

mechanism which operates to divert certain fluids in the system from their normal paths of flow, to alter the pressure at which certain fluids are circulated, and to prevent the flow of certain fluids in the system. I

It is a further object of the invention to provide a refrigerating system in which the produc-' tion of ice is regulated by diverting and regulating the flow of fluids within the system without introducing any moving parts'into the system to accomplish these results.

It is another object of the invention to provide a refrigerating system of the three-fluid type in which liquid refrigerant generated in the system is stored in a suitable receptacle and is utilized to prevent flow of inert gas through an ice freezing evaporator during a period during which it is desired to render the evaporator inoperative in order to free previously formed ice blocks.

inert pressure equal- I refrigerating system em r g the invention and in which the evaporator is shown in perspective.

Figure 2 is a transverse sectional elevational view of the evaporator-shown in Figure 1 and associated'with a suitable ice freezing water tank and a suitable low temperature insulated refrigerating compartment.

Figure 3 is a detailed view drawn to an enlarged scale illustrating the control mechanism.

Referring now to the drawings and first to Figure 1 thereof, there is illustrated athree-fiuid' absorption refrigerating system comprising a boiler B. an analyzer D, an air-cooled rectifier R, a' tubular air-cooledeondense'r C, an evaporator E, a gas heat exchanger H, a tubular aircooled absorber A, a liquid heat exchanger L, a

gas burner G for heating the boiler 23, and a circulating fan F which is driven by an electrical motor M. The above described elements are suitably interconnected by various conduits to form a plurality of gas and liquid circuits to which reference will be made in moredetail hereinafter.

The above described refrigerating system will be charged with a suitable refrigerant, such as ammonia, a suitable absorbent, such as water, and a suitable pressure equalizing medium, such as nitrogen.

The application of heat to the boilerB liberates refrigerant vapor from the strong solution It is a further object of the invention to provide a refrigerating system having a plurality of evaporators connected therein, one of which opcrates periodically and the other of which operates substantially continuously.

It is another object of the invention to provide a three-fluid absorption refrigerating system of the type utilizing a power driven circulator to propel a pressure equalizing medium through certain portions of the system which is controlled by varying the speed of the pressure equalizing medium circulator.

Other and further objects of the invention will become apparent as the description proceeds when taken in connection with the accompanying drawings in which:

therein contained, which vapor then passes upwardly through the analyzer D in counterflow to strong solution flowing downwardly therethrough. Further refrigerant vapor is generated from the strong solution in the analyzer by the heat of condensation of vapor of absorption solution generated in the boiler. The refrigerant vapor is conveyed from the upper portion of the analyzer to the upper portion of the condenser C by a conduit 4 I which includes the rectifier R. Any vapor of absorption solution which may pass through the analyzer is condensed in the rectifier and is returned into the boiler system through the conduit I I.

The refrigerant vapors supplied to the con- Q denser is liquified bfheatexchange with cooling air and is conveyed from the condenser into the evaporator E through a conduit [2.

The exact operation and description of the evaporator will be described in detail hereinafter,

for the present it is suflicient to say that the liquid refrigerant discharged into the evaporator E evaporates into a stream of pressure equalizing Figure 1 is a diagrammatic view illustrating a no medium flowing therethrough to produce refrigeration. The rich pressure. equalizing medium formed in the evaporator E is conveyed therefrom through a conduit. ii, the inner path of the gas heat exchanger H, and a conduit l6, which discharges into the bottom portion of the tubular inclined air-cooled absorber.A. The pressure equalizing medium flows upwardly of the gas heat exchanger H sorber vessel. The lean pressure equalizing medium formedin the absorber is conveyed from the upper portion thereof into the suction inlet of the circulating fan F by a conduit l3. The pressure equalizing medium is placed under pressure by the fan and is discharged therefrom througha conduit 23 into the outer path of the gas heat exchanger H. The pressure equalizing medium is then conveyed from the outer path into the evaporator E by a conduit 2|.

The lean solution formed in the boiler B by the generation of refrigerant vapor is drained therefrom through a conduit 23, the inner path of the liquid heat exchanger L, and a conduit 24 which opens into the upper portion of the absorber A. It is apparent that the upper portionv of the absorber A is at an elevation considerably above the liquid level prevailing in the boileranalyzer system wherefore some means must be provided in order to elevate the weak solution into the absorber. For this purpose, a small bleed-off conduit 25 is connected between the discharge conduit 20 of the circulating fan F and the weak solution conduit 24 below the liquid level normally prevailing in the boiler-analyzer system whereby the weak solution is elevated into the absorber by gas lift action. The weak solution flows downwardly through the absorber by gravity in counterflow relationship to the rich pressure equalizing medium refrigerant vapor mixture conveyed into the bottom portion of the absorber from the evaporator as previously described. The strong solution formed in the absorber is drained from the bottom portion thereof through a conduit 21 into the outer path of the liquid heat exchanger L from which the strong solution isthen conveyed to the upper portion of the analyzer'D by a conduit 23.

The evaporator comprises an upper U-shaped ice freezing conduit 33 and a lower W-shaped fast-freezing regfrigerating conduit 32 which is connected to the inert gas. supply and ret pipes 21 and I5, respectively.

The inert gas supply conduit 2i opens into a gas blocking and liquid refrigerant storage chamber 34 which is divided into a pair of chambers by a partition wall 35 which extends from the top wall of the chamber 34 to a point slightly spaced above the bottom thereof. The conduit 2| opens into the chamber 34 at the top thereof and on the left hand side of the partition 35, as viewed in Figure 1. A conduit 31 connects one leg of the evaporator conduit 30 to the top portion of the chamber 34 on the right hand side of the partition 35, as viewed in Figure 1. The other leg of the U-shaped conduit 30 connects directly in the inert gas return conduit l5.

The liquid refrigerant discharge conduit l2 opens into the conduit 30 adjacent its point of connection with the gas supply conduit 31. A gas lift pump conduit 39 is connected between the bottom portion of the conduit l2 adjacent the condenser and the vessel 34 on the right hand duit as below the level of its point of connection to the liquid conduit 12. A syphon conduit 4| is connected to the conduit l2 between the point of connection of the gas lift pump and the evaporator thereto. The syphon conduit 4| extends upwardly to a level well above thejbottom of the vessel 34 and then turns downwardly within the vessel 34 onthe left hand side of the partition 33. The free end of the syphon conduit 4| extends'to a level adjacent the bottom portion of the vessel 34 and below the bottom portion of the partition 35.

A .drain conduit 44 is connected to the conduit 33 adjacent the gas outlet portion thereof and opens into the gas inlet portion of the conduit 32 after extending therebelow to form a U-shaped liquid seal. A small dam 45 is mounted within the gas outlet portion of the conduit 30 to prevent liquid refrigerant from flowing into the conduit II.

Referring now to Figures 1 and 2, the functions of the various evaporator sections will be described in connection with certain other structures of the apparatus. Each leg of the U- shaped conduit 33 is provided with a plurality of inclined spaced freezing pads 40 which are adapted to receive the tapered bottom portion 43 of a water container 33. The evaporator section portion of the chamber 52 to underlie the bottom portion of the tank 50 and the U-shaped evaporator 33.

The gas burner G is supplied with fuel from any suitable source by a conduit 61 which includes a valve it operated by a solenoid-.8. The gas burner G is preferably of the type having a suitable safety cut-off mechanism incorporated therein which will discontinue all supply of fuel thereto in the event of complete flame failure at the burner. A small by-pass conduit 53 is provided around the valve 56 in order to obtain a small igniting or pilot flame on the burner G during periods of closure of the valve 56.

side of the partition 35. The conduit 39 includes the. valve 5i.

Electrical energy is supplied to the apparatus.

from a-suitable source of supply through a pair of wires 60 and 6|. The wire 3| connects directly to the circulating motor M and a wire 82 is connected between the wire ii and the solenoids for The wire 30 connects directly to one terminal of a suitable thermostatic switch mechanism 64. The mechanism 64 isillustrated diagrammatically herein; it may be any suitable or desired form of thermostatic refrigerating control switch mechanism which is adapted to be mounted within a refrigerating compartment to respond to the temperature condition of that compartment. The other terminal of the control mechanism 64 is connected to a wire 65 which connects to a wire 61 running to the solenoid S. One terminal of a thermostatic switch mechanism indicated generally at 10 and to be described more fully hereinafter is also directly connected to the wire 31. The. other terminal of the thermostatic switch mechanism 13 is connected by a wire H to a wire 12 which connects directly to the circumostatic element 83.

lating motor M. A suitable element 13 is connected between the wires 41 and 12 in parallel relationship with the thermostatic switch The thermostatic switch ll comprises a housing 8| constructed of insulating material and fastened to any suitable portion'of the evaporator conduit 30. As illustrated in Figure 1, the housing 4| is shown as being mounted in the bight portion of the U-shaped conduit 34 but any other suitable portion of that conduit may be utilized for mounting the housing if desired. Within the housing 8| a bimetallic thermostatic element 83 the temperature of the conduit 30 will drop to.

is rigidly attached at one end to the conduit 34 the circuit between those wires and thereby toshort circuit the resistance element IS.

The operation of this invention is as follows: Assuming that the apparatus has been inoperative and that the refrigerating chamber has 1 reached a temperature above that for which the thermostatic control mechanism 64 is set, the thermostatic control 64 will be'operated to energize the circulating motor M and the solenoid S to open the valve 58 to circulate the inert gas and to supply fuel to the burner G to generate refrigerant vapor. Refrigerant vapor will then be generated in the boiler, liquifled in the condenser and discharged through the 'conduit l2 into the evaporator conduit ll. The inert gas will be circulated by'the fan F and will be discharged into the conduit 2|. A small portion of the gas will flow through the conduit 32, which is considerably smaler in diameter than the conduit 3|, and may be provided with a restriction, if deiustifled by reason of the fact that the heavy insulation on the small compartment" makes the refrigerating load onthat compartment relatively low. under all conditions, even though the interior of the chamber 52 is maintained at a very low temperature while it is substantially full oi foodstuffs or of material to befrozen. a

The above described operation continues until ice, blocks have formed on, those portions of the inclined bottom 49 of the tank so in direct thermal contact with the freezing pads 48. When such ice blocks form to a predetermined thickness,

a very low value which will their cause the thermostat 43 to flex in a clockwise direction, as viewed in Figure 3, to close the circuit between the wires 61 and H. When this occurs, the resistance element 13 is short-circuited out of the motor circuit and the motor operates at its maximum speed. When the motor is operating at maximum speed, the fan developssuiilcient pressure to operate the gas lift pump 39 and all liquid refrigerant flowing through the conduit i2 is elevated into the chamber 34. The increased fan pressure tends to cause an increase in the rate of flow of-absorption solution due to'the greater quantity of gas discharged from the bleed conduit 25. If this increase approaches objectionable proportions, any suitable form of flow regulating means} such as that disclosed in my copending application Serial No. 220,195, filed July 20, 1938, now Patent No. 2,264,292, may be incorporated in the solution circuit.

The liquid refrigerant discharged through the conduit 39 into the chamber 34 very quickly seals the bottom portion of that tank in conjunction with the partition 35 and prevents the discharge of inert gasinto the conduit 31 and hence into the evaporator conduit 30. Under these conditions neither liquid refrigerant nor inert gas is being supplied to the conduit 30 and previously formed ice blocks melt free of the bottom wall of the tank 48 and floatto the surface of the water therein contained where they remain until sired, to limit the flow of gas therethrough. The

remainder of the inert gas will flow through the conduit 2|, the chamber 34, the conduit 31, and the U-shaped conduit 30 from which it will be returned to the conduit I5. I Due to the fact that the evaporator conduit 30 is relatively warm,the thermostatic element 83 within the switch housing 4| will be flexed in a counterclockwise direction, as viewed in Figure 3, to open the circuit between the wires 61 and l I thereby placing the rei sistance element 13 in series with the circulating motor M with the result that the speed of the motor will be something less than the maximum.

Under these conditions, the circulating fan F does not develop suflicient pressure to operate the gas lift pump 39 and all liquidrefrigerant formed in the condenser flows directly through the conduit |2 into the evaporator conduit at through which it flows by gravity in parallel relationship with the inert gas supplied through the conduit 31 as it is evaporating into the inert gas to pro-.

duce refrigeration. Any liquid refrigerant not evaporated in the conduit 30 flows through the U-shaped trap conduit 44 into the evaporator section 32 through which the liquid refrigerant flows in parallel with'the inert gas stream to refrigerate the insulated compartment 52.

fsyphon 4| as explained below.

The greatest refrigerating load occurs on the conduit 30 and only a small portion of the liquid refrigerant ever reaches the conduit 32. This is 75 ladled out for use. This operation will continue until the temperature of the conduit 30 again reaches a sufliciently high valueto actuate the thermostat 83 to open the circuit between the wires 61 and 1| to again slow down the motor 'by inserting the resistor 13 in series therewith.

During the period when the liquid refrigerant is collecting in the tank 34 there will be no refrigeration produced in the evaporator section 32 except that produced by liquid refrigerant present in the evaporator 30 when the inert gas supply thereto was cut oil, by reason of any liquid refrigerant which may flow through the conduit I2 without being diverted into the gas lift pump 39 and by any liquid which may flow through the The chamber 34 is so proportioned that the syphon 4| will always become active at least shortly before the conduit 30 reaches a temperature high enough to cause the thermostat 43 to open the circuit between the wires 61 and II. Qnce the syphon 4| has become active, it will syphon out substantially all the liquid refrigerant in the compartment 34 into the liquid refrigerant supply line |2 leading to the evaporator conduit 30. However, the capacity of the syphon 4| is substantially equal to but not greater than the capacity of the gas lift pump "so that the syphon 4| is never able to lower the level of the liquid refrigerant in the compartment 34 an amount suillcient to permit inert gas -by the syphon ll during the high speed cycle of the circulating motor simply flows through the evaporator section 3! and the conduit ll into the fast-freezing chamber refrigerating coil 32 where it evaporates into the inert gas stream flowing through that coil to produce refrigeration.

After the control mechanism has operated to decrease the speed of the circulating motor, the liquid refrigerant flows directly through the conduit l2 into the evaporator section 3| as before, but it is augmented by a stream of liquid refrigerant discharging through the syphon conduit ll from the compartment 84. However, refrigeration is not produced in the ice freezing conduit 30 until the syphon ll has emptied the compartment 34 of a quantity of refrigerant sufflcient to permit inert gas to flow therethrough. Liquid refrigerant discharging through the conduits II and i2 into the evaporator 30 prior to supply of inert gas to the evaporator ll is ultimately discharged-through the conduit 44 into the fast-freezing evaporator 32. The capacity of the tank 34 is not large wherefore the syphon fast-freezing coil 32 spreads throughout the length thereof, which is extensive as shown, and

slowly evaporates into the inert gas stream flowing through that coil.

The above described cycles of operation continue so long as the temperature within the main storage compartment of the refrigerator remains above the value for which the thermostatic control mechanism 64 is set to de-energize the refrigerating system. As long as the refrigerating system is operative the air within the main refrigerating storage compartment is refrigerated by flowing over the extensive surface of the tank SI and over the freezing coil ll. Due to the fact that the coil II is only periodically operative and also because of the fact that the temperature of the exposed walls of the water tank never reach a temperature below the freezing point of water, there is very little frost collection on the evaporator. The small amount of frost-which does collect on the coil 30 at each cycle thereof is melted off and flows into the receptacle during the ice melting period of the refrigerator. This serves to maintain the humidity within the refrigerating compartment at a high value which effectively increases the food preserving qualities of the refrigerating system.

The particular control herein disclosed automatically regulates the production of ice to sea-'- sonal demand therefore for the following reasons. During periods of warm weather when the demand for ice is greatest the loss of heat from the principal refrigerated compartment will be accelerated which will cause the control mechanism 64 to cycle the refrigerating apparatus more frequently and will thereby produce a large quantity of ice. On the other hand during periods of cool weather when the demand for ice is at a minimum, the loss of heat through the walls of the refrigerating cabinet will also be at a minimum which will automatically decrease the active periods of the refrigerating apparatus and hence the production of ice. 7

The above described apparatus is particularly advantageous by reason of the fact that it may be mounted in any desired type of refrigerator cabinet and will automatically produce a large quantity of ice blocks freely-floating in a body of water whereby any desired number of such blocks may conveniently be removed from the refrigerating apparatus simply by ladling them out of the body of water. In addition to the provision of means for freezing ice blocks and for cooling the refrigerating chamber, a low temperature insulated freezing compartment is provided.

The apparatus is particularly efllcient by reason of the fact that the ultimate destination of the liquid refrigerant is governed by the speed of the fan for circulating the pressure equalizing medium which in turn is thermostatically controlled by a mechanism entirely without the refrigerating system, whereby complete control of the flow of fluids within the system is achieved without the intervention of moving parts. Additionally, the liquid refrigerant is utilized to allow or prevent the flow of inert gas through certain portions of the evaporator whereby the production of refrigeration within the ice freezing evaporator section is impossible during periods of operation of the gas lift pump 30 by reason of the fact that liquid refrigerant will not evaporate in the conduit ll unless an inert gas is flowing therethrough,

While I have illustrated and described a particular embodiment of the invention in detail, the invention is not to be limited thereto but may be embodied in other constructional forms and variations without departing from the spirit of the invention or the scope of the appended claims.- I

I claim: 1. Refrigerating apparatus comprising a cooling unit, means for supplying a cooling medium to said cooling unit, means forpropelling a pressure equalizing medium through said cooling unit, refrigeration demand responsive means for diverting cooling medium flowing to said cooling unit into a storage vessel in the path of flow of the pressure equalizing medium, means in said vessel adapted to cooperate with cooling medium supplied thereto to block the flow of pressure equalizing medium to said cooling unit, and a syphon connected to drain the cooling medium from said vessel when the liquid level therein reaches a predetermined value.

2. Refrigerating apparatus comprising an evaporator, a liquid refrigerant supply means opening into said evaporator, means for supplying a pressure equalizing medium to said evaporator, a liquid refrigerant storage and gas blocking vessel interposed in said pressure equalizing medium supply means, a temperature responsive means operative to divert liquid refrigerant from the said liquid refrigerant supply means into said vessel in response to a predetermined temperature condition of said evaporator, means within said vessel adapted to cooperate with liquid refrigerant supplied thereto to block the flow of inert gas therethrough, and a syphon connected to discharge liquid refrigerant from said vessel period' ed to said cooling unit, teinparature responsive means for intermittently storing liquid refrigerant in a storage vessel, and means for flowing liquid refrigerant from said storage vessel into.

said cooling unit after a'predetermined collecting 4. Refrigerating apparatus comprising an evaporator including an ice freezing section and a compartment cooling section, means for supplying inert gas to each of said sections, means for supplying liquid refrigerant to said ice freezing section, means for conveying unevaporated refrigerant from said ice freezing section into said cooling section, a liquid gas seal device in the inert gas supply means for said ice freezing evaporator, means for divertingthe liquid 're- I frigerant from said supply means into said gas seal device, means for syphoning liquid refrigerant from said gas seal device into said ice freezing evaporator section, and control means for regulating said diversion means.

5. Absorption refrigeration apparatus comprising a boiler, an absorber, a plurality of evaporating elements, power driven means for propellinga pressure equalizing medium through a circuit including said absorber and said evaporating elements, means for liquefying refrigerant A vapor generated in theboiler, means for supply ing such liquid refrigerant to one of said evaporating elements, means for draining unevaporated refrigerant from said one evaporating element into another evaporating element, a liquid operated blocking device for preventing the fiow of pressure equalizing medium through said first mentioned evaporating element, a gas lift pump operated by pressure equalizing medium supplied from said circuit for diverting liquid refrigerant from said supply means into said blocking device,

means for draining liquid refrigerant from said blocking device into said first mentioned evaporating element, and means for controlling the operation of said gas lift pump.

6. Absorption refrigeration apparatus comprisinga boiler, anabsorber, a plurality of evaporating elements, power driven means for propelling a pressure equalizing medium through a circuit including said absorber and said evaporating elements, means for liquefying refrigerant vapor generated in the boiler, means for supplying such liquid refrigerant to one of said evaporating elements, means, for draining unevaporated refrigerant from said one evaporating element into another evaporating element, a liquid operated blocking device for preventing the flow of pressure equalizing medium through said first mentioned evaporating element, a gas lift pump operated by pressure equalizing meplying suchliquid refrigerant to one of said evaporating elements, means for draining unevaporated refrigerant from said one evaporating element into another evaporating element, a liquid operated blocking device for preventing the flow of pressure mediumthrough said first mentioned evaporating element, a gas lift pump operated by pressure equalizing medium supplied from said circuit for diverting liquid refrigerant from said supply means into said blocking device, means for draining liquid refrigerant from said blocking device into said first mentioned evaporating element, and means responsive to the temperature of said first mentioned evaporating element-for varying thepressure at which said power driven means circulates the pressure medium to render said gas lift'pump operative or inoperative in response to refrigeration demands, said means for draining liquid from said blocking device comprising a syphon having a capacity not greater than the capacity of said gas lift pump and arranged to become operative when the liquid levelin said blocking device reaches a predetermined value and to remove sumcient liquid from said blocking device ,to permit the pressure equalizing medium to fiow therethrough.

8. Absorption refrigeration apparatus comprising-a boiler, an absorber, 'a plurality of evaporating elements, power driven means for propelling a pressure equalizing medium through a circuit including said absorber and said evaporating elements, means for liquefying refrigerant vapor generated in the boiler, means for supplying such liquid refrigerant to one of said evaporating elements, means for draining unevaporated refrigerant from said one evaporating element intoanother evaporating element, said first mentioned evaporating element having a plurality of spaced heat conductors thereon, a water tank resting on said heat conductors, a liquid operated blocking device for preventing the fiow of pressure equalizing medium through said first mentioned evaporating element, a gaslift pump operated by pressure equalizing medium supplied from said circuit for diverting liquid refrigerant from said supply means into said blocking device,

means for draining liquid refrigerant from said blocking device into said first mentioned evaporating element, means for supplying electrical energy to said power driven means, a resistance element in series with said powerdriven means adapted to reduce the speed thereof to a value such that said power-driven means does not dedium supplied from said circuit for diverting liquid refrigerant from said supply means into said blocking device, means for draining liquid refrigerant from said blocking device into said first mentioned evaporating element, and means responsive to the temperature of said first mentioned evaporating element for varying the pressure at which said power driven means circulates the pressure equalizing medium to render said gas lift pump operative or inoperative in response a to refrigeration demands.

'7. Absorption refrigeration apparatus comprising a boiler, an absorber, a plurality of evaporating elements, power driven means for propelling' apressure equalizing medium through a circuit including said absorber and said evaporating elements, means for liquefying refrigerant vapor generated in the boiler, means for supvelop sufiicient pressure, in said pressure equalizing medium to operate said gas lift pump, a thermostatic switch connected in parallel with said resistance element adapted to respond to the temperature of said first mentioned evaporating element, ,and means responsive to the formation of ice blocks of a predetermined thickness within those portions of said water tank resting on said heatconductorsfor increasing the pressure at which the pressure equalizing medium is supplied to said gas lift pump for rendering said pump operative and for decreasing the pressure at which the pressure equalizing medium is supplied to said pump to render the same inoperative when previouslyuormed ice blocks have melted free of; those portions of said water tank in heat exchange relationship with said heat conductors. a

9. Absorption refrigeration apparatus comprising a boiler, an absorber, a plurality of evaporating elemen f, power driven means for propelling a pressure equalizing medium through a circuit including said absorberand said evaporating elements, means for liquefying refrigerant vapor generated in the boiler, means for supplying such liquid refrigerant to one of said evaporating elements, means for draining unevaporated refrigerant from said one evaporating element into another evaporating element, said first mentioned evaporating element having a plurality of spaced heat conductors thereon, a water tank resting on said heat conductors, an insulated low temperature refrigerating chamber in heat exchange relationship with said second mentioned evaporating section, a liquid operated blocking device for preventing the flow of pressure equalizing medium through said first mentioned evaporating element, a gas lift pump operated by pressure equalizing medium supplied from said circuit for diverting liquid refrigerant from said supply means into said blocking device, means for draining liquid refrigerant from said blocking device into said first mentioned evaporating element, and means responsive to the temperature of Said first mentioned evaporating element for varying the pressure at which said power driven means circulates the pressure equalizing medium to render said gas lift pump operative or inoperative in response to refrigeration demands.

10. Refrigerating apparatus comprising an ice freezing evaporator, a chamber cooling evaporator, means for propelling a pressure equalizing medium through said evaporators, means connecting said evaporators to said propelling means in parallel relationship, means for supplying liquid refrigerant to said evaporators, and means for discontinuing the supply of liquid refrigerant and pressure equalizing medium to said ice freezing evaporator without discontinuing the circulation of pressure equalizing medium through said chamber cooling evaporator.

11. Refrigerating apparatus comprising an ice freezing evaporator, a chamber cooling evaporator, means for propelling a pressure equalizing medium through said evaporators, means connecting said evaporators to said propelling means in parallel relationship, the arrangement being such that the major portion of the pressure equalizing medium flows through said ice freezing evaporator, means for supplying liquid refrigerant to said evaporators, and means for intermittently discontinuing the supply of liquid refrigerant and pressure equalizing medium to said ice freezing evaporator.

12. That improvement in the art of refrigeration which includes the steps of supplying refrigerant liquid and a pressure equalizing medium to an evaporating zone, intermittently collecting the liquid in the path of supply of the pressure equalizing medium to block fiow thereof by a body of refrigerant liquid and then draining the pressure equalizing medium flow blocking body of refrigerant liquid into the evaporating zone.

13. That improvement in the art of refrigeration which includes the steps of supplying refrigerant liquid and a pressure equalizing me,- dium to an evaporating zone, intermittently increasing the pressure of the pressure equalizing medium and introducing a portion of the pressure equalizing medium at the increased pressure into the liquid refrigerant to divert the liquid into the path of the main body of pressure equalizing medium enroute to the evaporating zone, blocking the fiow of pressure equalizing medium to the evaporating zone by a body of diverted refrigerant, decreasing the pressure of the pressure equalizing medium and discontinuing introduction of the pressure equalizing medium into the refrigerant liquid, and then draining the pressure equalizing medium fiow blocking body of refrigerant liquid into the evaporating zone.

l4. Refrigerating apparatus comprising an ice freezing evaporator, a water tank in heat transfer relationship with said evaporator at a plurality of points, a chamber refrigerating evaporator, means for supplying refrigerant to said evaporators, means for supplying pressure equalizing medium to said evaporators at either of two pressures, means operated-by pressure equalizing medium at the higher of said two pressures only for conducting liquid refrigerant from said refrigerant supply means to a storage chamber, and means for controlling said pressure equalizing medium supply means to supply pressure equalizing medium at the higher of said two pressures when ice blocks of a predetermined. size have formed in said water tank and to supply pressure equalizing medium at the lower of said two pressures when previously formed ice blocks have melted free of said tank.

15. Refrigerating apparatus comprising an ice freezing evaporator, a water tank in heat transfer relationship with said evaporator at a plurality of points, a chamber refrigerating evaporator, means for supplying refrigerant to said evaporators, means for supplying pressure equalizing medium to said evaporators at either of two pressures, means operated by pressure equalizing medium at the higher of said two pressures only for conducting liquid refrigerant from said refrigerant supply means into a storage vessel. and means for syphoning refrigerant from said storage vessel into said ice freezing evaporator when the liquid level therein reaches a predetermined value, and means for controlling said pressure equalizing medium supply means to supply pressure equalizing medium at the higher of said two pressures when ice blocks of a predetermined size have formed in said water tank and to supply pressure equalizing medium at the lower of said two pressures when previously formed ice blocks have melted free of said tank.

16. Absorption refrigerating apparatus comprising a solution circuit including a boiler and an absorber, a pressure equalizing medium circuit including an evaporator and said absorber, means for liquefying refrigerant vapor generated in said boiler, power driven means for circulating the pressure equalizing medium through its circuit, means for heating said boiler, temperature responsive means for controlling the energization of said power driven means and of said heater, means for conveying refrigerant liquid from said liquefying means into said evaporator,

means responsive to the pressure at which the pressure equalizing medium is supplied to said evaporator for diverting the refrigerant liquid into the path of the pressureequalizing medium flowing to said evaporator to block such flow when such pressure exceeds a predetermined value, means for draining the blocking liquid into the evaporator after a predetermined quantity of liquid has accumulated in the path of pressure equalizing medium flow, and means-respom sive to the demand for refrigeration at said evaporator for regulating the pressure at which the pressure equalizing medium is supplied thereto whenever said circulator is energized by said first mentioned temperature responsive means.

17. Refrigerating apparatus comprising a cooling unit, a water container in heat transfer relationship with said cooling unit whereby to form a body of ice in said container, means for supplying a cooling medium to said cooling unit, and condition responsive means for diverting the cooling medium into a storage vessel in response to a predetermined condition to permit said body of ice blocks 'frozen in said container to melt free of the wall of said container and to float on the surface of the contents thereof.

18. Refrigerating apparatus comprising a cool-' ing unit, means for producing refrigerant liquid, means for circulating a pressure equalizing medium through said cooling 'unit, means for conveying refrigerant liquid from said liquid refrigerant producing means to said cooling unit, and refrigeration demand responsive means for intermittently collecting liquid refrigerant from said conveying means and for interposing a body of the collected liquid refrigerant in the path of flow of the pressure equalizing medium to block the flow of pressure equalizing medium through said cooling unit. I

19. Absorption refrigeration apparatus comprising a boiler, an absorber, a plurality of evaporating elements, a motor operated pump for propelling a pressure equalizing medium through a circuit including said absorber and said evaporating elements, means for liquefying refrigerant vapor generated in the boiler, means for supplying such liquid refrigerant to one of said evaporating elements, means for draining unevaporated refrigerant from said one evaporatsel for preventing supply of pressure equalizing medium to said evaporator when the liquid therein reaches a predetermined depth, and means for emptying said collectingvessel when a predetermined quantity of refrigerant liquid has been collected therein, said apparatus being so constructed and arranged that ice blocks will be formed in said container when refrigerant is supplied to said evaporator and previously level and then to drain said container, and means for circulating an inert gas through said evaporator.

23. Absorption refrigerating apparatus comprising an evaporator, liquid refrigerant producing means, means for intermittently discharging a predetermined quantity "of liquid refrigerant into said evaporator comprising a container. means for conveying liquid refrigerant from said producing means to said container, and a syphon connecting said container and said evaporator arranged to become operative when the liquid level in said container reaches a predetermined level and then to drain said container, and

the flow of pressure equalizing medium through Y said first mentioned evaporating element, a gas lift pump operated by pressure equalizing medium supplied from said circuit for diverting liquid refrigerant from said supply means into said blocking device, means for draining liquid refrigerant from said blocking device into said first mentioned evaporating element, means for supplying electrical energy to said motor, a resistance element in series with said motor adapted to reduce the speed thereof to a value medium into said cooling unit, said last men-.

tioned means including a collecting vessel, a syphon arranged to empty the cooling medium collected in said vessel into said cooling unit, and means for circulating a pressure equalizing medium through said cooling unit, said circulating means including said collecting vessel and being arranged to block flow of said pressure equalizing medium by liquid collected in said collecting vessel. ,7

21. Refrigerating apparatus comprising an evaporator, a water container in heat exchange relationship therewith, means for supplying pressure equalizing medium and refrigerant liquid to said evaporator, means for diverting liquid refrigerant from said supply means into a collecting vessel, means within said collecting vesmeans for circulating an inert gas through said evaporator, said container being serially connected to said evaporator for flow of inert gas therethrough and arranged to block such" flow when a predetermined quantity of liquid has collected therein.

24. That improvement in the art of refrigeration which includes the steps of continuously generating liquid refrigerant, collecting the refrigerant in a storagerzone, intermittently discharging collected refrigerant intoan evaporating zone in heat transfer relationship with a body of material to be frozen at a plurality of freezing zones, evaporating the refrigerant to produce bodies of frozen material, and discontinuing the discharge of refrigerant into the evaporating I zone while collecting a fresh body thereof to allow the previously frozen bodies to leave the proximity of the evaporating zone.

25. An absorption refrigerating system comprising aninert gas circuit including. an evapo- I means to said evaporator, and means in said liquid refrigerant conducting means for intermittently collecting the refrigerant liquid supplied thereto'to alter the operation of the system and for, thereafter discharging the collected liquid to allow normal operation of the system to be resumed, said collecting means being included .in said inert gas circuit, the arrangement being such that collection of a predetermined quantity of liquid refrigerant will block the flow of inert gas until such collectedliquid is discharged.

v GEO. A. BRACE.

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