US2169284A - Refrigeration - Google Patents

Description

C. E. PLOEGER REFRIGERATION Aug. 15, 1939.

Filed Jan. 15, 1937 I l I l I I l l k m L x x x I. k

12/ ATTORNEY.

Patented Aug. 15, 1939 PATENT OFFICE REFRIGERATION Clyde E. Ploeger, Evansville, Ind, assignor to Servel, Inc., New York, N. Y., a corporation of Delaware Application January 15, 1937, Serial No. 120,698

2 Claims.

My invention relates to refrigeration, and has for its object to provide an improved control device for intermittent refrigeration apparatus.

The objects and advantages of my invention 5 will become apparent from the following description and accompanying drawing forming a part of this specification, and of which Fig. 1 diagrammatically illustrates intermittent refrigeration apparatus provided with a control device embodying my invention; Fig. 2.is a fragmentary sectional view taken on line 2-2 of Fig. 1 to illustrate more clearly parts of the control device; and Fig. 3-is a fragmentary sectional view illustrating a modification of the control device shown 15 in Fig. 1. v

' Referring to Fig. 1, I have shown my improved control device in connection with intermittent refrigeration apparatus comprising a generator-absorber Ill adapted to be heated by a gas burner II which projects its flame into the lower end of a flue I2 extending vertically upward through the generator-absorber Ill. A suitable combustible gas is delivered from a source of supply through conduit I3, control device I4 hereinafter to be described, and conduit I5 to the burner I. A small by-pass conduit I6 may be connected around the control device I4 to provide a small ignition or pilot flame at the burner I I when the main supply of gas is shut off.

. To the upper part of the generator-absorber I0 is connected a vertically extending conduit ll which is connected at its upper end to anaircooled condenser l8 provided with heat transfer fins IS. The condenser I8 is connected to an a evaporator 20 including a loop connected to a receiver 2|. The evaporator 20 and receiver 2| may be arranged in a thermally insulated storage space 22.

The refrigeration apparatus is charged with a solution of refrigerant and an absorption liquid, such as, for example, a thirty per cent solution of ammonia and water. The system operates with alternate periods of absorption of refrigerant and expulsion of refrigerant vapor. During the rela 45 tively high vapor pressure expulsion period, the burner applies heat to the generator-absorber Ill whereby refrigerant is expelled out of solution. The refrigerant vapor flows upward through conduit I'l to the air-cooled condenser I8 in which 50 it is liquefied, and the liquid refrigerant accumulates in the evaporator 20.

When the heat supplied to the generator-absorber III by the burner I I is stopped, the generator cools whereby refrigerant is absorbed into absorption liquid and flows from the evaporator 20 4 7 through the condenser I8 and conduit l1 and into the generator-absorber I 0. In this absorption period, which is at a reduced pressure, the refrigerant within the evaporator 2|! evaporates and takes up heat thereby producing cold. When the 5 temperature of the evaporator 20 increases to a predetermined value during the absorption period, gas is again delivered to the burner I I' to start a heating period.

In accordance with my invention, I provide the control device I4 for controlling the flow of fuel to the burner II whereby the alternate periods of expulsion of vapor and absorption o'frefrigerant are automatically regulated, The control device l4 includes a casing 23 having inlet and outlet openings formed within bosses 24 and 25 to which are connected the conduits I3 and I5, respectively.

A vertical sleeve 26 is threadedly secured at its lower end to the bottom wall of the casing 23 at the outlet formed by the boss 25. A valve seat 20 21 is formedat the lower end of the sleeve 26 above which are located'openings 28 in-the wall of the sleeve.-

Within the sleeve .26 is disposed a valve 23 which controls the flow of gas to the burner I I in response to the action of thermal elements 30 and 3|. The upper thermal element 30 comprises an expansible bellows which is secured at its upper end to the top of the casing at an opening 32 formed therein. The expansible bellows 30 is 30 connected by a tube 33 to a thermal bulb 34 which is arranged in good thermal relation with a short vertically extending conduit 35 that is'closed at its lower end and connected at its upper end to the upper part of the receiver 2|. The lower thermal element 3| also comprises an expansible bellows which is secured at its lower end to the bottom of the casing at an opening 36 formed therein. The expansible bellows 3| is connected by a tube 31 to a thermal bulb 38 which is arranged in good thermal relation with a vertical conduit 39 connected at its upper and lower ends to the upper and lower parts of the receiver 2|. The expansiblebellows 30, tube 33 and bulb 34, and also the bellows 3|, tube 31 and bulb 38, each constitute an expansible fluid thermostat containing a volatile fluidwhich increases and decreases in volume with corresponding changes of temperature.

The lower end of the upper expansible bellows 30 is adapted to bear against a lever 40 which is pivotally connected to a side wall of the casing 23. The outer end of the lever 40 is disposed above the'upper end 01 "a member II which is formed integrally with the valve 29. When the expansible bellows 3| expands sufficiently, the lever 49 is caused to move downward and move the valve 29 to its closed position. A coil spring 42 is connected at its upper and lower ends to the lever 49 and the top wall of the casing 23 to retract the lever 49 when the expansible bellows 30 contracts. The tension of the coil spring 42 is adjustable from the exterior of the casing 23, as shown at 43.

The upper end of the lower exp'ansible bellows 3| is adapted to bear against a lever 44 which is pivotally connected to the side wall of the casing 23. To the outer end of the-lever 44 is secured a relatively strong leaf spring 46 which serves as a pawl and engages the teeth of a ratchet wheel 41. The ratchet wheel 41 is disposed between the side walls of the hollow upper part of the member 4| and is rotatably mounted on a pin 49. Between each side wall of the hollow part of the member 4| and the ratchet wheel 41 is provided a nonrotatable disk 59 of the general shape shown in Fig. l. The disks 50 are journaled on the pin 49 and are curved inwardly, as shown in Fig. 2, and frictionally engage the sides of the ratchet wheel 41.

A stop 5| is provided within'the casing 23 to limit the extent of upward movement of the lever 44 due to expansion of the expansible bellows 3|. A coil spring 52, which is similar to the coil spring 42, is connected at its upper and lower ends to the lever 44 andthe bottom of the easing 23 to retract and move the lever 44 downwardly when the expansible bellows 3| contracts. The tension of the coil spring 52 is also adjustable from the exterior of the casing 23, as shown at 53.

The operation of the control device I4 is as follows: Assuming that a heating or vapor expulsion period is in progress, the valve 29 and other parts of the control device H are substantially in the position shown in Fig. 1, and gas flows through conduit |3, casing 23 and conduit |5 to the burner During such heating period refrigerant is expelled out of solution in the generatorabsorber I9, is condensed in the condenser, and. collects in the evaporator 29 and receiver 2|. The refrigerant condensate flowing into the evaporator 29 and receiver 2| is at a relatively high temperature, and, when the receiver 2| becomes filled with liquid and liquid flows into the conduit 35, the thermal bulb 34 is heated. When'the bulb 34. is heated to a temperature, such as F., for example, the increase in volume'of, the volatile fluid causes expansion of the expansible bellows 30 whereby the lever 46.1srnoved downward such a distance that the outer end thereof is caused to bear against the upper end of the member 4| and move the valve 29 downwardly to its closed position. During this downward movement of the valve 29 the lever 44 remains in its upper position against the stop 5| and the teeth of the ratchet wheel 4'! slide or slip over the outer 'end of the leaf spring 46.

When gas is no longer delivered to the burner H and heat is no longer applied to the refrigeration apparatus, the absorption period starts, as described above, and the evaporator 29 becomes cold. The cooling of the evaporator 29 at'the beginning oi' the absorption period causes the volatile fluid in bulb 39, tube 3'! and expansible bellows 3| to become reduced in volume whereby the latter contracts and permits the spring 52 to move the lever 44 downward. With such downward movement of the lever 44, the resilient leaf spring 46 causes rotation of the ratchet wheel 41 against the frictional engagement effected by the disks 50, due to the fact that the valve 29 has previously been moved to its closed position by the downward movement of the lever 49. When the lever 44 is in its lowermost position, the engagement of the resilient leaf spring 46 with the ratchet wheel 41 eiiectively maintains the valve 29 in its closed position.

The cooling of the evaporator 20 at the beginning of the absorption period also causes the volatile fluid in bulb 34, tube 33 and expansible bellows 39 to become reduced in volume whereby the latter contracts and permits the spring 42 to move the lever 4|) upward. Due to the engagement of the leaf spring 46 and the ratchet wheel 41 and the downward movement of the lever 44, however, the valve 29 remains in its closed position even though the lever 49 is moved upward and the outer end thereof no longer bears against the upper end of the member 4|.

After a lapse of time the ability of the refrigerant to evaporate isreduced, and, due to the low refrigerant level in the evaporator 20 and the supply of heat to the evaporator, the temperature of the evaporator rises. Upon a rise of the evaporator temperature to about 20 F., for example, the increase in volume of the volatile fluid in the expansible bellows 3| causes the latter to expand and move the lever 44 upward against the tension of the spring 52. With such upward movement of the lever 44, the valve 29 is moved upward due to the engagement of the resilient leaf spring 46 with the teeth of the ratchet wheel 4| The frictional engagement effected between the ratchet wheel 41 and friction disks 59 is sufficient to prevent the ratchet wheel from turning so that the valve 29 is effectively moved upward and away from its seat 21. This permits gas to be supplied to the burner H to start a heating period of the refrigeration apparatus.

Instead of forming the member 4| integrally with the valve 29 and having a positive connection therebetween, the member 4| and valve 29 may be loosely connected so that the valve 29 will not immediately move to its open position with expansion of the bellows 3| and upward movement of the lever 44. Such a modification is shown in Fig. 3 in which the lower end of the member 4| is provided with a recess 54 to receive the upper reduced end 55 of the valve 29.-

The member 4| is provided with a slot 59 to receive a pin 51 which is fixed to the upper end 55 of the valve 29.

In the operation of the modification just described, the pin 51 bears against the upper end of the slot 56 when the valve 29 is in its closed position. At the end of an absorption period, when the ability of the refrigerant to evaporate is reduced, the rise in temperature of the evaporator 2|! causes the expansible bellows 3| to expand and move the lever 44 upward against the tension of the spring 52. Due to the loose or flexible connection provided between the valve 29 and member 4|, however, the valve 29 opens only after a predetermined upward movement of the member 4|. When the pin 51 contacts and bears against the lower end of the slot 56, the valve 29 is then moved to its open position with continued upward movement of the member 4|. A lag of any number of degrees may be introduced at the lost motion connection of the valve 29 and member 4|.

Although I have shown and described particular embodiments of my invention, it will be apparent to those skilled in the art that modifications and changes may be made without departing from the spirit and scope of my invention, as pointed out in the following claims.

What is claimed is:

1. A control device for intermittent absorption refrigeration apparatus including a control member, a plurality of thermostats, one of said thermostats being connected to operate said member in only one direction, a notched wheel frictionally 10 journalled on said member, means including a resilient pawl engaging the notches in said wheel connecting another of said thermostats to said? member.

2. A control device as set forth in claim 1 in which said control member comprises two parts having a lost motion connection therebetween and said wheel is journalled on one of said parts and said first thermostat is connected tooperate said part.

CLYDE E. PLOEGER. m

Images