US2178561A

US2178561A - Absorption refrigerating apparatus

Info

Publication number: US2178561A
Application number: US94940A
Authority: US
Inventors: Curtis C Coons
Original assignee: Hoover Co
Current assignee: Hoover Co
Priority date: 1936-08-08
Filing date: 1936-08-08
Publication date: 1939-11-07
Anticipated expiration: 1956-11-07

Description

Nov. 7, 1939. c. c. COONS ABSORPTION REFRIGERATING APPARATUS 'Filed Aug. 8, 1936 9 on the interior Patented Nov. 7, 1939 Application August 8,

This invention PATENT OFFICE 13 Claims.

relates to continuous absorption refrigerating apparatus using inert gas and more particularly means for regulating the pressure therein.

It is desirable to have installed in an absorption refrigerating system using inert gas, means to increase automatically the total pressure in the system as the room temperature increases and to decrease the total pressure automatically as the room temperature decreases. peratures, the condensation of ant entering the condenser at lower room the system diminished by some the system will operate with a perature thus decreasing the and otherwise improving the system.

It is an object of the present vide pressure regulating means tomatic and which ing the desired pressure in a tem using inert gas.

It is another object of novel means for regulating the frigerating system.

Other objects and advantages of the arrangement and construcnovel features tion of parts as will be apparent temperatures with the At high room temgaseous refrigeris thus assured, and

pressure of regulating means, lower boiler temrate of corrosion operation of the invention to prowhich will be auwill be reliable in maintainrefrigerating systhe invention to provide pressure in a rereside in certain from the following description taken in connection with the accompanying drawing in which Figure 1 is a diagrammatic a continuous absorption ing inert gas and in which the is incorporated, the pressure shown in cross section.

r Figure 2 is an enlarged view of a portion of the the arrangement of pressure chamber used in representation of refrigerating system uspresent invention chamber being Figure l and showing the bellows construction thereof, the view being taken on the line 2-2 of Figure l and Figure 3 is a transverse cross-sectional view of the pressure chamber,

the line 3-3 thereof.

Referring to seen that a continuous absorp the drawing in the view being taken on detail, it will be tion refrigerating J these parts being connected by various conduits to form the completed refrigeration system.

A conventional gas lift pump ll may be employed to lift absorption liquid from the boiler into the gas separation erant developed in the boiler through the conduit l2 into chamber and the refrigsystem may flow the condenser C where it is liquefied and flows into the evaporator E through the conduit [3.

Inert gas is circulated between the absorber and the evaporator by means of the inert gas ABSORPTION REFRIGERATING APPARATUS Curtis 0. Coons, North Canton,

to The Hoover Company,

a corporation of Ohio Ohio, assignor North Canton, Ohio,

1936, Serial No. 94,946

absorber by means of the ab-.

from the bottom of the absorber back to the boiler through the conduit 20.

The system may be charged with ammonia, water and nitrogen as refrigerant, absorption liquid and inert gas in accordance with known practice.

In accordance with the present invention, a pressure chamber 2| is connected to some part of the system, as for example the bottom of the absorber, by means of the conduit 22. The pressure chamber 2| is merely a closed vessel and has an expansible chamber or bellows construction 23 therein. Any other suitable collapsible device may be substituted for the bellows 23, as for example, a rubber cylinder.

In the arrangement shown, the bellows 23 is welded to the top of the cylinder 2| and a valve 24 is connected to the top of the cylinder so that fluid may be charged into the expansible bellows chamber independently of the charge to the refrigerating apparatus in general.

From experiment, it has been estimated that in a 60 degree Fahrenheit room, an absorption refrigerating system using a refrigerant, an absorbent and an inert gas of the usual construction with the absorber and condenser air-cooled, the system will operate satisfactorily with the internal pressure about 200 pounds per square inch. On the other hand, in a 100 degree Fahrenheitroom the same system should have a pressure of about 3'70 pounds per square inch to operate satisfactorily. Without a pressure regulator, the internal pressure would not increase sufficiently under normal conditions if the room temperature changed from 60 degrees Fahrenheit to 100 degrees Fahrenheit for the internal pressure of this system would be increased only up to about 250 pounds per square inch.

In accordance with the present invention, the desired pressure change may be brought about within the system, however. The pressure chamber 2| andbellows 23 function to increase internal pressure in the refrigerator with an increase in room temperature by the expansion of the bellows 23 as the result of the expansion of the fluids therein. In order for this system to operate, the fluids within the bellows 23 must expand with an increase in room temperature and create a higher pressure than the expansion of the fluids in the refrigerating system itself creates. As the bellows 23 expands, it compresses the gases in the cylinder 2| and forces them into the refrigerating apparatus, thus increasing the total pressure in the refrigerating system.

The bellows is caused to expand with an increase in room temperature by an increase in pressure within the bellows due to the heating of the fluid or fluids contained therein.

It will be apparent, therefore, that for any desired pressure increase in the internal pressure of the refrigerator for a given increase in room temperature, it is only necessary to select a system of fluids to be charged into the bellows 23 that will yield the desired pressure at any desired room temperature. The fluids selected for charging into the bellows 23 must, of course, be non-corrosive with respect thereto.

For an air-cooled, ammonia absorption refrigerator using water as absorbent and nitrogen as inert gas-it may be desirable to increase internal pressure from about 200 pounds to 370 pounds per square inch with an increase in room temperature from 60 to 100 degrees Fahrenheit as in the example given above. In this system, liquid ammonia and liquid propane are proposed in ac cordance with the present invention for'use in the bellows 23.- Since these two fluids are practically immiscible, each will exert its own vapor pressure independently of the other. As a consequence the system within the bellows 23 will have a pressure of about 210 pounds at a temperature of 60 degrees Fahrenheit and may have pounds at a temperature of 100 degrees Fahrenheit.

The bellows 23 must be so proportioned with respect to the volume of the cylinder that the correct relation to the volume of the refrigerating apparatus is maintained. The volume of the cylinder and the bellows must be made sufliciently large in relation to the volume of that part of the refrigerator into which the gas is compressed that the pressure in the refrigerator will be equivalent to the pressure in the bellows or at least approximately equivalent at all temperatures. It is roughly estimated that if the gas part of the refrigerator such as the absorber, evaporator and inert gas conduits had a volume of four liters, the bellows must be able to expand into a volume of three liters to produce a pressure increase from 210 to 3'70 pounds per square inch.

If the pressure vessel were installed above the absorber, the temperature of the pressure vessel would always be above the room temperature because it would receive heat from the absorber. The absorber temperature during normal operation is 20 to 25 the room temperature. If the pressure vessel is so installed the temperature of the pressure vessel could be made to vary from 80 degrees Fahrenheit to 120 degrees Fahrenheit with an increase in room temperature from 60 to 100 degrees Fahrenheit. Under these conditions liquid ammonia alone could be charged into the bellows and would give a sufflcient pressure to expand the bellows for at 120 degrees Fahrenheit the vapor pressure of ammonia is 290 pounds.

It will be apparent, therefore, that almost any desired pressure increase within the bellows could the bellows by the use of such systems or combinations as ammonia and propane, ammonia alone, ammonia and water, ammonia propane and water, and ammonia and some inert gas such as nitrogen and hydrogen.

degrees Fahrenheit higher than- The instant invention produces several desired functions within the system with results greatly improved over those previously produced by similar apparatus. In previous devices which were designed for the purpose of regulating the threefluid absorption refrigerating system in response to changes in atmospheric temperature conditions, the pressure in the apparatus was raised by increasing the quantity of inert gas in the active portions of the system and by trapping out of the active portions of the system a volume of substantially pure refrigerant vapor equal to the original volume of inert gas added to the active circuit and existing at the higher pressure. Such apparatus produces the desired result of increasing system pressure but it also greatly impairs the efliciency of the increase the pressure of the system and will ma- I terially increase the quantity of inert gas circulating through the active portions of the system, but it will not materially change the quantity of refrigerant contained in the solution or the quantity circulating through the'active portions of the system.

When the pressure of the apparatus increases, the quantity of ammonia vapor present in the the apparatus. The quantity of refrigerant which is added to the condenser is not great because of the relatively small volume of the condenser tubes which have In summation, therefore, it may be said that a rise in temperature produces the following changes in the system. The quantity of inert gas in the active circuits is materially increased. The quantity of refrigerant circulating through the active portions of the circuit is slightly increased. The quantity of refrigerant contained in solution may be slightly increased or decreased depending entirely upon the proportions of the condenser and the pressure vessel, but in any event no material change is produced in the solution concentration. Moreover, due to the greater quantity of inert gas provided at higher pressure, the concentration'of refrigerant vapor in the inert gas circuit tends to decrease in the well known manner in order to permit eflicient It will be apparent, therefore, that while only one embodiment of the invention is shown and described herein. various changes may be made in the arrangement and construction of parts without departing from the spirit of the invention or the scope of the annexed claims.

I claim:

1. The combination with a continuous absorption refrigerating system using an inert gas of means for regulating the pressure therein in accordance with temperature conditions, said means including a pressure vessel connected to a part of said system and an expansible element in the pressure vessel for varying the volume therein in response to temperature conditions.

2. The combination with a continuous absorption refrigerating system using an inert gas of means for regulating the pressure therein in accordance with temperature conditions, said means including a pressure vessel connected to a part of said system and an expansible element in the pressure vessel for varying the volume therein in response to temperature conditions, said expansible element consisting of a bellows chamber filled with an expansible fluid.

3. The combination with a continuous absorption refrigerating system using an inert gas of means for regulating the pressure therein in accordance with temperature conditions, said means including a pressure vessel connected to a part of said system and an expansible element in the pressure vessel for varying the volume therein in response to temperature conditions, said expansible element having ammonia and propane therein.

4. The combination with a continuous absorption refrigerating system using an inert gas of means for regulating the pressure therein in accordance with temperature conditions, said means including a pressure vessel connected to a part of said system and an expansible element in the pressure vessel for ,varying the volume therein in response to temperature conditions, said expansion chamber having fluids therein which cause the pressure therein to increase a greater amount per degree increase in temperature than the normal increase in pressure in the refrigerating system per degree increase in temperature.

5. The combination with an air-cooled absorber of a continuous absorption refrigerating system using inert gas of a pressure vessel connected thereto, said pressure vessel havingan expansible element associated therewith and adapted to change the effective volume of the pressure vessel as the temperature of operation of the absorber varies.

6. The combination with a continuous absorption refrigeration system using inert gas of means for regulating the operation of the system in accordance with temperature conditions comprising a device for varying the effective volume of the system.

'7. The method of regulating the internal conditions of an air cooled continuous absorption refrigerating system using inert gas which includes the step of increasing or decreasing the volume of such a system in response to temperature changes.

8. That improvement in the art of continuous absorption refrigeration using inert gas which comprises automatically varying the quantity of inert gas contained in an inactive portion of the system in response to external temperature conditions, without materially altering the quantity of refrigerant contained in the active portion of the system.

9. That improvement in the art of refrigeration which includes the steps of evaporating a refrigerant into an inert gas in an evaporating zone to produce refrigeration, removing the refrigerant vapor from the inert gas in an absorbing zone by contacting the mixture with an absorbent for the refrigerant, rejecting the heat of absorption to cooling air, and adding or subtracting inert gas to said absorbing zone in response to changes in the temperature of the cooling air without materially altering the concentration of the refrigerant in the absorbent.

10. 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 supplying refrigerant generated in said boiler to said evaporator in liquid phase, means included in said pressure equalizing medium circuit adapted to propel pressure equalizing medium therethrough, and means for altering the volume of said pressure equalizing medium circuit without substantially altering the volume of said solution circuit.

11. That improvement in the art of refrigeration which includes the steps of expelling refrigerant from a generating zone, circulating a substantially constant quantity of absorption solution through a circuit including the generating zone and an absorbing zone, circulating a pressure equalizing medium through a circuit including an evaporating zone and the absorbing zone, circulating a substantially constant quantity of refrigerant through a circuit including all of said zones and a heat rejecting zone, and varying the quantity of pressure equalizing medium circulating through the evaporating and absorbing zones in response to changes in atmospheric temperature conditions.

12. That improvement in the art of refrigeration involving a system having a plurality of active zones through which various fluids circulate which includes the steps of circulating a pressure equalizing medium through a circuit including evaporating and absorbing zones, circulating absorbing solution through a circuit including generating and absorbing zones, liquefying vapor expelled in the generating zone by heat exchange with a cooling medium, conveying the liquid refrigerant to the evaporating zone, altering the concentration of one of said fluids in response to changes in the temperature of maintaining the quantity of refrigerant in the active zones of the system substantially constant.

13. Refrigerating apparatus comprising a pressure equalizing medium circuit including an evaporator and an absorber, a solution circuit including a generator and said absorber, means for supplying refrigerant vaporized in said generator to said evaporator in liquid phase, and means for withdrawing pressure equalizing medium from said pressure equalizing medium circuit and for adding pressure equalizing medium to said pressure equalizing medium circuit in accordance with external temperature conditions, said last mentioned means beingconstructed and arranged to withdraw or add pressure equalizing medium without substantially aifecting the quantities of other fluids circulating in the apparatus.

cua'rrs c. COONS.

the cooling medium, and