US2557373A - Control means in absorption refrigeration system - Google Patents

Description

June 19, 1951 CQQNS 2,557,373 Y CONTROL MEANS IN ABSORPTION REFRIGERATION SYSTEM Filed March 14, 1947 vvvmnnnnu- INVENTOR.

Curtis CZ Coons BY 7 r ATTORNEY.

Patented June 19, 1951 CONTROL ANS IN ABSORPTION REFRIG ATION SYSTEM Curtis 0. Coons, Can Hoover Company, poration of Ohio Ohio, assignor to-The Canton, Ohio, a cor- Application March 14, 1947, Serial No. 734,673

. 11 Claims.

This invention relates to the art of refrigeration and more particularly to a control mechanism for a dual intermittent absorption type refrigerating apparatus.

It is a principal object of the invention to provide the refrigerating apparatus of the above described character provided with a refrigeration control which is variably responsive to the de-' mand for refrigeration, for example, to the temperature of the evaporator or of the cabinet, to regulate the operation of the dual intermittent refrigerating system.

It is a further object of the invention to provide a refrigerating system of the above described character in which a control operating in response to satisfaction of a particular refrigerating demand modifies the operation of the normal cycling control mechanism of the system to prevent the cycling control from applying heat to a generator-absorber normally next to be heated. and to allow the cycling control mechanism to operate in a normal manner to initiate heating of the absorber-generator which has previously completed its absorbingphase of operation and to initiate absorption in the generator-absorber which has previously completed its generating phase of operation when the master control responds to a demand for refrigeration.

It is a further object of the invention to provide in a system of the above described character an arrangement by which the generator which completes its generating phase of operation during a period when the refrigeration demand control has responded to a refrigeration satisfied condition is held at a low heat just sufficient to prevent re-abs'orption therein until the refrigeration demand control responds to a further demand for refrigeration.

Otherobjects and advantages of the invention will become apparent as the description proceeds when taken in connection with the accompanying drawing wherein one form of the invention is illustrated partly schematically and partly in section.

The refrigerating system as such comprises two identical intermittent refrigerating systems. Since these systems are identical in all respects with each other only one will be described. Corresponding parts of the two systems are identified by corresponding reference characters distinguished by a prime. The evaporator and liquid receiver of the left hand system are not visible in the drawing as they lie behind the identical evaporator and liquid receiver of the right hand system.

The left hand refrigerating system, as viewed in the drawing comprises, a generator-absorber B which is provided with a central products of combustion flue l0 surrounded by an annular jacket H forming with flue l0 an annular chamber for a cooling medium.' An outer cyclindrical member I! forms an annular space with the cooling jacket I I and the absorbent material is contained within this annular space. Though my invention is applicable to various types of intermittent absorption machines. for convenience in illustration the generator-absorber structure shown here is a type particularly adapted to use a dry salt such as strontium chloride as the absorbing medium.

A conduit l4 communicates with the space between the jackets II and I2 and with the condenser C for the purpose of conducting refrigerant vapor from the generator to the condenser. The vapor is liquified in the condenser by heat exchangewith atmospheric air and the resulting refrigerant liquid is conveyed through conduit ii to the liquid receiver R of the evaporator E. The liquid receiver R and evaporator E are not shown in the drawing as they lie behind corresponding identical elements R and E, respectively.

If an absorbent such as water or strontium chloride is utilized in this system the refrigerant is preferably ammonia. Other refrigerant and absorbent combinations are well known to the art and may be used herein if desired.

As shown herein the evaporator E lies against one side of a freezing chamber compartment It to refrigerate the same and also to refrigerate the air within the refrigerator cabinet. It will be understood that the evaporator E is similarly arranged on the opposite side of the compartment It. The evaporator generally illustrated herein is of the type disclosed in detail in U. S. Letters Patent No. 2,379,278 issued June 26, 1945. However other evaporators may be utilized if desired.

The condensers C and C have common fins as shown in order to facilitate heat transfer and to conserve space. I

The generator-absorber cooling system comprises the chamber formed between flue l0 and jacket H as heretofore mentioned. The foregoing chamber is connected to a cooling system condenser II by means of a conduit It. The cooling system condensers I1 and I1 discharge into a common reservoir I9 which communicates with a control valve chamber 20 by means of a conduit 2 I. The control valve chamber 20 communicates with the lower ends of the cooling jacket H ass-ers 3 and II by means of conduits 22 and 22', respectively. The chamber 24 houses a valving element comprising valve plugs 24, 24' positioned to control the flow of cooling medium into the conduits 22 and 22 respectively. The valve plugs 24 and 24' are rigidly connected together by a shaft element 25. A valve actuating lever 25 is'pivotally mounted in chamber and has a sliding fit with the shaft 25. Springs 21 and 21 are positioned around the shaft on each side of the lever 26 so that there is a resilient driving connection between lever 28 and shaft in both directions for purpose to be developed hereinafter.

Gaseous fuel burners 20, 20' are positioned to heat the boilers B and B by discharging products of combustion through the flues It and Ill respectively. Fuel gas is supplied to the burner Ill from a source of supply indicated generally at H through a safety control pilot device 32, conduit 22, control gas valve 34 and the conduit 55. The pilot control device is of a known type in which extinguishment of the pilot flame actuates a thermostatic device to shut off all flow of gas into the system beyond the pipe 3| both to the pilot and to the burners l0 and 30'. Flash tubes 26, 25 are arranged to ignite the burners 2i and 30 from the flame of the pilot device 22.

Gas control valve 34 comprises a casing 40 formed with a. valve seat 4! which is in a wall of the casing separating those parts. thereof which communicate with the gas conduits 23, 35 respectively. The valve plug element 42 is positioned to seat in the opening 4| to control the flow of gas between conduits 32 and 35. The plug 42 is mounted upon an actuating shaft 42 which passes through the .wall of housing and is movably sealed to prevent escape of gas by a flexible diaphragm 44. A compression spring engages the valve actuating shaft 43 and urges the valve plug 42 to the closed position.

A cycling control mechanism is provided to regulate the operation of the gas control valves and the cooling medium supply valve. This mechanism comprises thermostatic expansible bellows and 50' which are responsive to the temperature of the boilersB and B, respectively.

The valves shafts 43, 43' are positioned in spaced relation to be engaged by a valve actuating lever 52 mounted upon a fixed pivot 55. As shown in the drawing the upper free end of lever 52 extends between the ends of the shafts 43. 43' of the valves. The lower end of lever 52 has a sliding driving connection at 54 with the valve actuating lever 25. A snap actuating arm is pivotally mounted on the pivot 55 and is connected to the lever 52 by a snap spring 56. The snap acting arm 55 is positioned between the opposed thermostatic bellows 50 and 50 to be actuated thereby. Stop elements 51, 51' and 55, 54 are provided for the snap acting lever 55 and valve actuating lever 52, respectively. In addition to the above described cycling control the apparatus is provided with a refrigeration demand control which comprises a thermostatic bellows 55, shown arranged to be responsive to the temperature of the ice freezing chamber I. This element may be responsive to the temperature within the food storage space of the refrigerator cabinet or directly responsive to the evaporator. temperature as particular conditions require. The bellows 52 is mounted on a suitable flxed support 6| which may, for example but without limitation, be a portion of the interior or exterior wall of the refrigerator cabinet structhe force of a range adjustment spring 42 which is seated against an adjusting nut and control dial device 63 for the purpose of varying the force which the compression spring 52 applies to the bellows 50. The adjusting element 52 will be mounted either inside or outside the cabinet, as the particular design may indicate as desirable. in position to be operated by the user to adjust the temperature range of the refrigerating unit.

The bellows 50 has a pivotal pin driving connection 65 with the actuating lever 84. An interrupting arm 64 pivotally mounted upon a flxed pivot 61 is arranged to be brought into and to be moved out of the path of movement of the valve actuating arm or lever 52. The lever 66 is operated by the snap actuating arm 64 by means of the snap spring 58 which connects the two.

As the bellows 50 expands indicating a demand for refrigeration, the actuating lever 54 is moved toward the position shown. AS this lever passes over center the snap spring 88 actuates the arm 65 to move the same out of the path of movement of the valve actuating arm 52 after which the cycling control functions independently of the refrigeration control. When the demand for refrigeration is satisfied the bellows 50 will collapse moving the lever 64 toward its opposite position. As this lever passes over centerthe snap spring 88 actuates lever 56 with a snap action to move the same into the path of movement of the valve actuating arm 52. Suitable stops 6!! are provided to limit the arc of movement of lever 56. The temperatures at which the bellows 50 actuates the interrupting lever 68 are varied by adjusting the adjusting dial and nut 63 to vary the bias of the spring 62 against which the bellows operates.

As illustrated in the drawing the parts are so proportioned that expansion of the bellows 50, indicating that the generator-absorber B has completed the end of a generating period, will operate the snap acting lever 55 over center and thus tend to shift the valve actuating element 52 to the right as shown in the drawing. If the bellows 50 is at this time responding to a demand for refrigeration the lever 66 will be out of the path of movement of the valve operating lever 52. Under these conditions the gas valve 4i42 will close under the bias of the spring 45. The lever 52 will open the valve 4l42' to supply fuel to the burner 30'. Simultaneously with this operation the cooling medium control valve operating lever 26 will rotate in a counter-clockwise direction relieving tension upon the spring 21 and tensioning up spring 21 until the valve structure 24, 24f shifts to the right to shut off the flow of cooling medium into conduit 22' andto allow flow of cooling medium into the conduit 22 to begin cooling of the generator-absorber B.

' When the refrigeration demand is satisfied, the bellows 50 collapses and snaps lever 55 into the path of movement of lever 52. When the above condition obtains, normal operation of the apparatus continues until the end of the generating period of operation obtaining when refrigeration demand is satisfied whereupon one of the cycling control thermostat 50-50 expands to actuate the snap acting lever 55 which in turn actuates lever 52 to the extent permitted by the lever 55. When the lever 52 is arrested by the lever 56dotted line positions of these levers, for example-the gas valve controlling the flow of fuel to the burner associated with the generatorabsorber which has just completed a generating period of operation is held in slightly open positure. The bellows expands and contracts against 15 tion--dotted line position of valve 42, for example-to restrict the fuel supply to an amount just suilicient to maintain the same at a temperature high enough to prevent absorption. The gas control valve associated with the other generator absorber will however remain in fully closed position. Upon this limited movement of the lever 52 the lever 26 will move correspondingly and will relieve some of the tension upon the previously compressed spring 21 or 21' without however altering the previous position of the cooling medium control valve structure 24, 2-4. This results in the following condition: One generator-absorber continues to be set up for absorbing operation; though by the time the foregoing series of events has occurred it has already absorbed substantially all the refrigerant from the evaporator. "The other generator-absorber has completed a generating period of operation and is simply held in stand-by condition with a low heat input thereto to prevent absorption for the time being.

. When the temperature rises and bellows 60 expands in response to the refrigerating demand and snaps the lever 66 away from engagement with the valve actuating lever 52 which then completes the movement under the bias of the spring 56 which the lever 56 previously interrupted.

In the upper portion of the figure of the drawing the evaporators, the primary and secondary condensers and their immediately associated mechanisms are shown associated with a domestic refrigerating cabinet. The evaporator structure is within the insulated food storage compartment of the cabinet in the top portion thereof whereas the primary and secondary condensers C, C, and l1, II are positioned in an air flue ll formed vertically along the rear wall of the cabinet structure.

The two refrigerating systems comprising the present invention should be designed to carry the maximum load condition which may reasonably be anticipated in practical use of the machine with continuous operation of the generator-absorbers under the control of the cycling control means without interruption thereof by the refrigeration demand control. If these conditions are satisfied, whatever the particular temperature setting the user may desire to place upon the adjustable control dial 63, the refrigeration demand control will occasionally interrupt operation of the cycling control at lighter loads in order to exercise control of the temperatures carried in the food storage space and/or freezing space of the refrigerating system.

It is characteristic of the illustrated form of the invention that whenever the refrigeration demand control operates the cycling control interrupting lever, the generator then operating on an absorbing phase of operation continues so to operate until it has fully absorbed the refrigerant in its associated evaporator. Similarly the generator operating on a generating phase of operation at the time the cycling control is actuated as above specified continues to operate on the generating phase of operation until the cycling control operates in response to a condition indicating that the generator has substantially discharged itself of its full complement of refrigerant vaporl The foregoing coupled with the fact that the generator which has just completed a generating period of operation is held on low new demand for refrigeration.

The foregoing is a Preferred control procedure but modifications are contemplated. For example, the low standby heat may be eliminated, this is particularly true where the generator-absorbers are well insulated as under these conditions a generator-absorber takes a long period of time to cool by radiation and no significant absorption of a refrigerant vapor will occur in any event. In this type of operation the gas valve shaft 43 will be relatively short so that the valve is completely closed when the lever 52 is stopped by the lever 66. Additionally or alternately the cooling medium valve structure may be modified by making the valve plugs 24 and 24' independently movable with a lost motion connection from each to the lever 26 and springs urging'the plugs to closed position so that there is a period when both valves are in closed position which coincides with the position of lever 26 when lever 52 is stopped by lever 66.

In a general sense my invention pertains to those types of dual intermittent absorption refrigerating systems in which each system is systematically heated and cooled to generate and reabsorb refrigerant vapor respectively. In such dual systems the two systems areheated and cooled in out of phase relation with each other. The heating and cooling effect is regulated by a thermostatically operated cyclin control which not only heats and cools each system systematically but also heats and cools the two systems in out of phase relation with each other according to some pre-determined schedule of operations. It is particularly characteristic of the present invention that the refrigerant control modifies the operation of the cyclin control to prevent it from applying heat to a system which was not last heated in the normal schedule of operations of the cycling control.

I claim:

1. In a refrigerating apparatus, a pair of intermittent refrigerating systems each including a generator-absorber, a condenser and an evaporator connected in circuit; means for cooling said generator-absorbers, means for heating said generator-absorbers, a cycling control for operating said heating means and said cooling means to heat and cool each of said generator-absorbers alternately in out of phase relaticnship to each other, said cycling control means including a member movable from a first position in which one of said generator-absorbers is heated and the other generator-absorber is cooled through an intermediate range of movement in which neither generator-absorber is heated to a second position in which said one generator-absorber is cooled and said other generator-absorber is heated, a refrigeration demand control including a member movable into and out of the path of movement of said first member to interrupt movement thereof prior to the point at which heat is applied to a previously cooled generator-absorber and cooling medium is applied to a previously heated generator-absorber.

2. In a refrigerating apparatus, a pair of intermittent refrigerating systems each including a generator-absorber, a condenser and an evaporator connected in circuit; a gas burner arranged to heat each of said generator-absorbers, a gas valve having high and low heat and 03 positions arranged to govern the flow of gas to each of said burners, a cooling system charged with a cooling medium having a heat absorbing part in heat exchange relation with each of said generator-absorbers, a control valve structure in said cooling system arranged to direct cooling medium into a selected one of said heat absorbing parts, actuating mechanism associated with said gas valves and said cooling medium flow control valve arranged to heat and cool said generator-absorbers alternately in out of phase relation by moving the gas valve controlling the gas burner associated with one generator-absorber to the high heat position and moving the cooling medium valve to supply cooling medium to the heat absorbing part associated with the other genorator-absorber, refrigeration control means including a member shiftable into position to arrest operation of said actuating mechanism as it is operating to reverse the application of heat and cooling medium to said generator-absorbers at a point at which the cooling medium control valve has not been operated and the gas valve previously held in high heat position has been operated to the low heat position.

3. Refrigerating apparatus including a pair of intermittent absorption refrigerating systems of the type which are successively heated and cooled in operation, means for heating and cooling said systems, means for governing the operation of said heating and cooling means, thermostatic cycling control means responsive to the thermal condition of portions of said systems including a snap actuating lever operated by said thermostatic means, an-operating lever connected to be actuated by said snap actuating lever by means of a snap spring, said operating lever being arranged to operate said governing means to heat and cool each of said systems successively and in out of phase relation with each other, refrigeration demand responsive thermostatic means, an interrupting lever connected to be operated by said refrigeration demand responsive means and mounted to be moved into the path of movement of said operating lever by said refrigeration demand responsive means when the refrigeration demand is satisfied, said interrupting lever being so mounted with respect to said operating lever that said operating lever is moved into engagement therewith by the bias of said snap spring after said cycling control means has operated said snap actuating lever to discontinue heating of one of said systems, and said operating lever is stopped by said interrupting lever against the bias of said snap spring before it has operated said governing means to initiate heating of the refrigerating system next to be heated.

4. Refrigerating apparatus including a pair of intermittent absorption refrigerating systems of the type which are successively heated and cooled in operation, means for heating said systems, means for regulating said heating means to apply heat at a high generating rate or a low standby rate to said refrigerating systems, means for cooling said refrigerating systems by passing a cooling medium in heat exchange relation therewith, means for governing the operation of said cooling means to control the flow of cooling medium, cycling control means normally automatically operable to actuate said regulating means and said governing means to apply a high generating heat and cooling medium to each of said systems successively and in out of phase relation with each other, and refri eration control means operable when the demand for refrigeration is satisfied to modify the normal operation of said cycling control means to cause said cycling control means to reduce the heat to the system operating on its generating period of operation to a low standby heat at the end of its generating period of operation without initiating cooling thereof.

5. Refrigerating apparatus including a pair of intermittent absorption refrigerating systems of the type which are successively heated and cooled in operation, means for heating and cooling said systems, and mechanism governing said heating and cooling means to control the production of refrigeration by said systems including refrigeration demand responsive control means, means for operating said heating and cooling means to heat and cool each of said systems successively and in out of phase relation with each other, when said refrigeration demand responsive means is responding to a demand for refrigeration, and

means for heating one of said systems with a low standby heat at the end of a normal heatim period thereof and for barring cooling of said one system when said refrigeration demand responsive means responds to a refrigeration demand satisfied condition.

6. Refrigerating apparatus including a pair of intermittent absorption refrigerating systems of the type which are successively heated and cooled in operation, means for heating and cooling said systems, control means for controlling the operation of said systems including means for regulating said heating means, means for governing said cooling means, a cycling control means including means for operating said regulating means and said governing means to heat and cool each of said systems successively and in out of phase relation with each other, and refrigeration demand responsive means operable when refrigeration demand is satisfied to continue heating the previously heated system at a low standby heat rate and to prevent the application of heat to the other system.

I. Refrigerating apparatus comprising a generator-absorber, a condenser and an evaporator connected in circuit; means for heating said generator-absorber to operate the same on a generating period of operation, means for cooling said generator-absorber to operate the same on an absorbing period of operation, a movable member for operating said heating means and said cooling means for heating and cooling said generator-absorber successively, an energy storing and releasing means arranged to release stored energy to operate said movable member, cycling control means for storing energy in said energy storing means for shifting said generator-absorber from generating phase to absorbing phase operation and vice versa, and refrigeration demand control means operable so long as refrigeration demand is satisfied to arrest operating movement of said member against the bias of said energy storing means to prevent initiation of a period of operation of said generator-absorber opposite in phase to the immediately preceding period of operation.

8. Refrigerating apparatus including a pair of intermittent absorption refrigerating systems of the type including parts which are successively heated and cooled in operation, means for heating and cooling said parts, means for governing the operation of said heating and cooling means, cycling control means for operating said governing means to heat and cool each of said systems successively and in out of phase relation with each other and refrigeration demand responsive means operable in response to a refrigeration demand satisfied condition to alter the operation of said cycling control means as it is operating to reverse the application of heat and cooling medium to said generator-absorbers to reduce the heat to the heated part of the generating generator-absorber to a low standby heat rate just suf- 'ficient to maintain the heated generator-absorber above an absorbing temperature and to lock said cycling control means against operating said gov-.

erning means to supply cooling medium to said generator-absorber.

9. Refrigerating apparatus comprising; a generator-absorber, a condenser and an evaporator connected in circuit; means for heating said generator-absorber; means for cooling said generator-absorber; and means for controlling the operation of said heating means and said cooling means including, a member movable from a first position in which said heating means is activated through a second position in which said heating means and said cooling means are inactive to a third position in which said cooling means is active, means responsive to the temperature of said generator-absorber for operating said movable member to activate said heating means and said cooling means successively, and refrigeration demand responsive means operable in response of intermittent absorption refrigerating systems each including a part which is successively heated and cooled in operation; means for heating said parts; means for cooling said parts; and means for controlling the operation of said heating means and said cooling means including, a member movable from a first position in which said heating means is activated to heat one of said parts and said cooling means is activated to cool the other of said parts through a, second position in which said heating means is de-activated to a third position in which said heating means is activated to heat said other part and said cooling means is activated to cool said one part, means responsive to the temperature of said parts for operating said movable member to activate said heating means and said cooling means to heat and cool each of said parts successively in out of demand responsive means operable in response to a refrigeration demand satisfied condition for arresting said movable member in said third position when moved thereto by said operating means.

11. In a control mechanism for a dual intermittent absorption refrigerating apparatus of the type including, a pair of elements which are alternately heated and cooled in out of phase relation,

means for heating said elements, and means for cooling said elements; means for controlling the operation of said heating means and said cooling means including, a member movable from a first position in which said heating means is activated to heat one of said elements and said cooling means is activated to cool the other of said elements through a second position in which said heating means is de-activated to a third position in which said heating means is activated to heat said other element and said cooling means is activated to cool said one element, means responsive to the temperature of each of said elements when heated to a predetermined temperature for operating said movable member to activate said heating means and said cooling means to heat and cool said elements successively in out of phase relation to each other, a stop means movable into an operating position in which it engages and stops said movable member in said third position when moved thereto by said operating means, means biasing said stop means to an inoperative position, and refrigeration demand responsive means for moving said stop to said operative position when refrigeration demand is satisfied and for holding said stop in said operative position as long as refrigeration is satisfied.

CURTIS C. COONS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,988,496 Hulse et a1 Jan. 22, 1935 2,379,278 Coons June 26, 1945 FOREIGN PATENTS Number Country Date 119,154 Australia Nov. 16. 1944 Certificate of Correction Patent No. 2,557,237 3 June 19, 1951 CURTIS G. COONS It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 45, after cycling control. insert the following paragraph: While I have illustrated and described the invention in considerable detail, it is to be understood that various changes may be made in the arrangement, proportion and construction of parts without departing from the spirit of the invention or the scope of the appended claims.

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 4th day of March, A. D. 1952.

[SEAL] THOMAS F. MU PHY,

Assistant Commissioner of Patents.

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