US2368438A - Refrigeration - Google Patents

Description

Jan. 30, 1945.

s. w. E. ANDERSSON REFRIGERATION Filed July 18, 1941 5 Sheets-Sheet 2 Jan. 30, 1945. s. w. E. ANDERSSON REFRIGERATION Filed July 18, 1941 '3 Sheets-Sheet 3 J INVENTOR ATTQRNEY moved, I r The invention is shown in Fig. 1 in connection Patented Jan.. 30, 1945 REFRIGERATION Evansville, Ind., assignm- Sven W. E. Andersson,

to Servel, Inc., of Delaware New York, N. Y., a corporation Application July 18', 1941, Serial No. 402,911

8 Claims,

This invention relates to refrigeration and,

more particularly paratus.

It is an object of the invention to provide a reto control of refrigeration apfrigerator control responsive to both cooling element and box air temperature conditions in a efiect defrosting.

manner to maintain proper air temperature and Various other objects, features and advantages of the invention will be apparent from the following description'in connection with the accompanying drawings, in which:

Fig. 1 is a more or less diagrammatic view with parts in vertical section, illustrating a refrigerat ing system having a control device embodying the present invention,

Fig. 2 is an enlarged vertical sectional view of the control device of Fig. 1. v A

Fig.3 shows part of the device of Fig. 2 in a different operative position, and

Fig. 4 is a fragmentary top view-of the control device of Fig. 2 with the cover of its casing rewith a refrigerating system like that described in Patent No. 2,207,838 to A. R. Thomas, issued July 16, 1940, and provided with a heat transfer system like that described in Patent No. 2,182,934- to A. R. Thomas, issued December 12, 1939.

The heat transfer system includes a cooling element Ill disposedin a thermally insulated refrigerator storage compartment l l and comprising a finned pipe coil l2 connected to a header l3. This heat transfer system also includes a condenser coil l4 connected to the evaporator I0 by a conduit l 6, and forming with said evaporator part of a 'closed fluid circuit containing a suitable volatile heat transfer fluid suph as methyl chloride. Condenser coil I4, is disposed below the evaporator Ill and is refrigerated in an evaporator unit l5 forming part of the refrigerating system.

Since the condenser I 4 is disposed at alower level than the evaporator Ill, suitable means is employed to raise condensed'liquid tosaid'evaporator. For that purpose, a lift device is provided comprising a vessel Il, connected to the lower 8 outlet end of thecondenser l4, and a second v'essel 2| having its .upper part connected to the upper and lower parts of said vessel I! by conduits l8 and I9 respectively. The lower end of the'ves- Thomas Patent No. 2,182,934, hereby incorporated in thi description.

The evaporator l5, forming part of the refrigcrating system shown in said Thomas Patent No. 2,207,838, has a suitable refrigerant such as ammonia introduced therein through a conduit" 25. This ammonia evaporates and diffuses in the cooling unit l5 into an inert gas such as hydrogen to produce a refrigerating effect, which condenses the fluid in the condenser coil'l4. Theresultant gas mixture of inert gas and" refrigerant flows from the lower part of the evaporator. l5 through a conduit 26, the outer passage of a gas heat exchanger 21, and a conduit 28 into an absorber 29. In absorber 29, refrigerant gas is absorbed by a suitable liquid absorbent such as water which enters through a conduit 32. The inert gas, which is practically insoluble and weak in refrigerant,

'is'returned to the evaporator l5 through a conduit 33, through a plurality of tubes forming the inner passage of the gas heat exchanger 21, and

The enriched ab- -sorption liquid is conducted from the absorber then through a conduit 34.

29 through the outer passag'eofa liquid heat' exchanger 35, vessel 36, andlanalyzer' 38 to generator 40. 8 )IA coil 42, connected to generator 40 by a pipe 4|, is heated by a burner 43, whereby liquid refrigerant is raised by vapor lift actionthrough conduit 44 into a vessel 45, in which refrigerant vapor and absorption liquidare separated. Liberated refrigerant vapor flows downward through. a conduit 46 into the generator 40. This vapor together with the refrigerant vapor expelled out of solution in the generator 40 by, the heating action of the burner 43, flowsthrough the analyzer 38 intothe vessel 36. From vessel 36 the re- 7 frigerant vapor flow upward through a conduit to the gas heat sel 2! is in turn connected by a conduit 22,to'the receiver l3 for conducting liquid to the evaporator Ill. The construction and, operation of the lift device 11, 2| is shown and described in said 41 and a liquid cooled rectifier 48 into a condenser 50 in which the refrigerant is liquefied. The liquefied'refrigerant flows from this condenser 50 through conduits 5| and 52- into the cooling Jacket of rectifier 48. FrOm'the rectifier, liquid refrigerant flows to the evaporator l5 through a conduit-i3, coil 54, and conduit 25. In coil 54 liquid refrigerant is pre-cooled by evaporation thereof into enriched gas which flows from and exchanger 2l through conduits and 56. 3

The weakened absorption liquid from which,

refrigerant has separated flows from the vessel .45

through a conduit 51, throughthe inner passage of liquid heat exchanger .35, through the conduit 32' and into the upper part of the absorber 29. T e heat liberated with absorption of'the refrigerant vapor in absorber 28 is transferred to a cooling medium which flows upward through a coil 58. 001158 is connected to a conduit 68 extending through the condenser 58, whereby the latter is cooled by the same cooling medium as the absorber 28.

A vessel 6| having an opening 82 in the bottom thereof is arranged in the absorber 28. The upper part of this vessel 8| is connected by a conduit 63 to the upper part of the conduit 52, so that any inert gas which may passinto the con: denser 58 can flow into the inert gas circuit. Any refrigerant vapor not liquefied in condenser 58 flows through conduit 83 to displace inert gas in the vessel 6| and force such gas into the inert gas circuit through the opening 62, thereby increasing the total pressure in the system. With such increase in pressure in the system, an adequate condensing pressure is obtained to insure condensation of refrigerant vapor in the condenser 58.

The flow of fuel gas to the burner 43 is regulated by a control device 65 comprising a valve casing 66. The interior of this casing 88 is divided by a flexible diaphragm 81 into anupper chamber 68 and a lower chamber 88. The latter chamber is in turn divided by a'valve partition 18 into two valve passages II and I2. Communication between these passages II and I2 is controlled by a pair of valves 82 and 83 to be described. The lower part of the casing 88 has a gas inlet I3, leading into the passage II, and connected by. a conduit 14 to a suitable source of fuel gas.=' The lower part of the casing 68 also has a main gas outlet 15, connected to the burner 43 by a conduit I8.

For controlling-the gas flow between the inlet 13 and the outlet I through the passages II and "I2, the valve partition I8 has an opening within which is fixed a valve seat member 11 shown in the form of a cylindrical sleeve. This sleeve I1 is provided with a central hub 88 connected to the peripheral section of said sleeve by spaced radial arms 8|. The lower and upper ends of the sleev 11 serve as seats for valves 82 and 83 disposed in passages I2 and II respectively. Valves 82 and ,83 are formed of any suitable gas resistant material such as artificial rubber commercially known as DuPrene or Thiokol.

The valve 82 is part of a high temperature safety device, which cuts off the flow of gas to the burner 43 undercertain conditions, and which comprises a resilient snap-action dia phragm 86 below the seat member 11, and a, rigid plate 81 secured between the lower end of the casing 66 and a coverplate 88. Passing through openings in the plates 81 and 88 and secured to said plate 81 is one end of a tube. 98, the other end being connected to a thermal bulb 8i, arranged in thermal contact with the liquidcooled rectifier 48 as shown in Fig. 1. The tube 98 and bulb 9| are charged with suitable volatile fluid,

and with the resilient diaphragm 88 and plat 81 constitute an expansible fluid thermostat.

Theresilient' diaphragm 88 is adapted to bear against the lower end of arc-shaped leaf sprin 83, secured at its upper end to the valve 82. A spiral spring 84 is retained in position between the hub .88 andvalve 82 to urge the latter to its normal open position shown in Fig. 2.

If for any reason the temperature of the liquid cooled rectifier 48 becomes relatively high, for

ed by metal plates 91 and 98, fixed to opposite sidesof said diaphragm.

. In order to obtain a pilot flame for the burner 43, there is provided a small pilot burner I88, supplied with fuel gas from a conduit "II, which is connected to a by-pass I82 formed in the casing 88. This by-pass I82 leads from the valve passage II, so that it will always be in communication with the gas supply from the inlet13. A suitable spring-pressed adjustable plunger valve I83 may be utilized to regulate flow of gas through this by-pass I82.

In order to operate the valve 83 in accordance with pressure changes in the coils I2, there is provided in the upper part of the casing 68 an expansible pressure diaphragm H8, secured to and in communication with a hollow hub I I I. To this hub III is connected one end of a capillary tube H2, which extends through an opening in the casing 66, and which connects at its other end into the secondary refrigerating system at a suitable point to sense the pressure in the coils I2. For instance, the capillary tube H2 may be connected at point H3 to the conduit I8 at the inlet side of the condenser I4 as shown in Fi 1. order to make the diaphragm H8 sensitive to pressure changes within the refrigeration range, but still enableit to withstand the high pressures encountered during shut-down periods,

' it is made of relatively thin hard material, and

instance, due to the failure of the cooling medium to circulate properly through the condenser 58,

' the expansible fluid thermostat becomeseflective ing into the hub I I I.

the movement thereof is limited by an internal stop H4 secured to said diaphragm and extend- I'hi's diaphragm H8 may be manufactured by forming two dished discs of beryllium copper in the soft state, sealably securing these discs in opposed relationship by silver soldering and heat treating to maximum hardness.

A spring diaphragm H5, secured to the casin 66 and attached to the hub I I I, serves as a guide for the diaphragm H8 in its flexing movement,

and also serves as a means for holding the hub III up against an adjusting screw H8 threaded in the upper end of said casing. Thisscrew H8 is connected to a control knob I88 provided with a pointer I81, which can be moved over a dial or scale I88 on the casing 86.

Disposed below the pressure diaphragm H8 is a flexible sealing diaphragm I I1, used as a safety device to separate the vented space H8 above from the sealedgas space 68 below, sothat in case said pressure diaphragm develops a leak,no I

refrigerant from the secondary system can enter the fuel gas line.

Bleeder gas can enter the gas space 68 from the inlet I3 through a passage I 2I interconnecting said space and said inlet. Pressed-in screens I24 are provided in this passage I2I, and an adjustable spring-pressed valve plunger I25 is employed in said passage to restrict the flow of bleeder gas I therethrough. A screw I26 permits access to this inlet bleeder passage I2I for cleaning purposesit.

The bieeder gas flows from the space '68 through a valve passage I28, communicating with a low pressure line I28. The flow of this gas from the space 88 into the passage I28 is controlled by an I outlet bleeder valve I21 operated into open position by the pressure in the diaphragm I III. When this valveII21 is closed, the gas pressure on opposite sides of the diaphragm-'61 will be equalized,

so that the weighted valve 83 is closed, and the main supply or fuel gas to the burner 43 is cut off; When the valve I21 is opened, the valve 88 will open as will be more fully described, and

flow of gas to the lished.

The mechanism for operating the outlet bleeder valve I21 from the pressure diaphragm H is of the toggle type and includes a lever I30, which is disposed between a pair of fixed spaced bracket flanges I32. and which is pivoted at I3I in V- shaped grooves formed in said bracket flanges. Connected to the intermediate section of the lever I30 is a stud I I9, yieldably pressed against the bumer 43 will re-estabunderside of the pressurediaphragm IIO by a.

spring I36 to be more fully described;' The free or movable end of this lever I30 is bent over and cut out in the middle to form a pair of spaced ears provided with pivot grooves I33. A U,-shaped trip lever I34 is pivoted at one end in these grooves, and is provided in its bend near the other hooked one end of the coil spring I36. The other end of this spring I36 is hooked into a'sharp edged hole I31 of a valve lever I38. This valve lever I38 rection urging'it into contact with the pressure diaphragm 'I I0. This is due to the fact that the of the snap lever I34.

pivoting point I3I is always above the center line Consequently, no return spring is needed.

While the refrigerating system is on, and the controls are in the position shown in Fig. 2, the

,end with asharp edged hole I to which is i is in the shape of a yoke, and has its side arms flanking the trip lever I34, and pivoted in grooves I40 of the fixed bracket flanges I32.

The outlet bleeder valve I21 is attached to the shank section of the lever I38 in such a manner that it will align itself with a valve seat member I4I; Two holes I42 are drilled through the valve stem at right angles and countersunk from both sides. Through the lower hole is inserted a pivoting pin I43 located in a; recess'in the lever I38, and through the upper hole is hooked the end of a spring I44, which holds the valve I21 in place. Upward movement of the lever I38 is limited by a differential adjusting screw I46, threaded in the casing 6-6, and sealed against gas leakage by a spring-pressed packing I48.

In the operation of the control device so far described, while the refrigerating system is cutoff and the cooling coils I2 defrosting, th valve operating levers I 30, I 34 and I38 are in the position shown in Fig. 3. In this condition of the valve operating levers, the pivot point I33 will be disposed above the central line of the spring I36, so that the bleeder valve I21 will be closed and the main fuel valve 83 consequently also closed. The distance of this pivot point I33 above the center line of the spring I36 for any predeterk l mined pressure in thediaphragm I I0 depends on the setting of the adjusting screw I I6.

- When the pressure diaphragm I I0 expands, the I lever I30 moves counter-clockwise about its pivot point I3I, so that the left end of said lever moves down until the pivoting point I33 passes below the center line of the spring I36. Th lever I34 will then snap upward by theaction of the spring.

I 38 into the position shown in Fig. 2. Due to the resultant change in direction of pull by the spring I36 on the lever I38, this lever snaps up until it makes contact with the differential adjusting screw I46 as shown in Fig. 2, thereby opening the valve I21. Due to the small resistance of the outlet bleeder valve I21 and 'the outlet passage I28 in comparison to the greater resistance of the pressure in the cooling coils I2 will be decreasing, thereby causing contraction of the pressure diaphragm I I0. While diaphragm H0 is contracting.

the lever I30 is moving clockwise about its pivot axis I3I. so that the pivoting point I33 is moving upward, from the position shown in Fig. 2 below the center line of the spring I36 to that. shown in Fig- 3 above said center line. When the pivoting point I33 reaches above this spring center line, the spring I36 will pull the snap lever I34 down ward to the position shown in Fig. 3 in stop'engagement with the base of the bracket flanges I32, and due to the resultant change in the position of said spring, the valve lever I38 is also pulled down to close the bleeder valve I21. In this closed position of the valve I21, the main fuel valve 83 will close, and the refrigerating system will be cut-off.

Although the snap action in either valve closing or opening operation has'been described as taking place in two steps, actually the two snap actions of each simultaneously.

'The amount of movement required by the pressure diaphragm between the opening and closing snap can be varied by, the adjusting screw-I46.

The further it is backed up as viewed in Fig. 2. the more the diaphragm I I0 has to contract before the closing snap occurs, since the distance of the-pivot point I33 below the center line of the spring I36 depends on the inclination of the lever I38, which in turn depends on the axial position of the adjusting screw I46.

With the construction-of the control device so far described, the cut-on operation of the refrigerating system is controlled by the pressure in the cooling coil I2. and is set for anyipredeter mined coil pressure through adjustment of the screw I I6. The cut-off operation of the refrigcrating system may also be controlled by the pressure in the cooling coil I 2, and be set for any predetermined coil pressure by'adjustment of the screw I46. These pressures correspond with the coil temperatures, but have no definite relation 1 ISI is desirably operated by low voltage current from a small :bell transformer I49, but may be operated also from dry cells or other suitable source of electricity. The screw I46 is provided with an axial bore I 52 for slidably receiving a g operation take place substantially I55 in the magneti field of the solenoid I5I The plunger I53 is urged to its uppermost inactive position shown in Fig. 2 by a coil spring I55 in th hollow of the solenoid I5I, seated on the top of the screw I46, and bearing against the underside of the plunger head I54. In order to' dampen upward return movement of the plunger I53 when the solenoid I5I is de-energized, the plunger head I54 is cup-shaped, and receives a coil spring I56 bearing at its upper end against the solenoid housing I50.

The circuit of the solenoid I5I is controlled in accordance with the air temperature in the compartment I I. For that purpose there is provided an electric thermostat I60 (Fig. 1), which is subject to the air temperature in the compartment II as sensed by a thermostat element I6I. The electric thermostat I 60 is desirably of the heating type, that makes contact upon falling temperature. This is desirable because electric energy will then be consumed only during a short period of each cycle. However, a thermostat making contact upon rising temperature can be used if the solenoid action is reversed.

The-electric thermostat I60 is calibrated and adjustable to afford any desired cut-off temperature setting, and has desirably a narrow temperature differential between the closing and the opening of its contact.

While the refrigerating system is on, the control device will he in the postion shown in Fig. 2, with the valve lever I38 abutting the screw I46,

, the bleeder valve I21 open, and the main fuel valve 83consequently open. During this time, the air temperature in the fixture II is. going down, and when it reaches a predetermined point as determined by the setting of the thermostat I60, the contact thereof will close. This will energize the solenoid I5I, and force the plunger I53 downward against the valve lever I38 to move said 'open the bleeder valve I21 until actuated .by the pressure control mechanism by the expanding action of the pressure diaphragm IIO as described. In'the meantime, while the valve lever I30 is down and the bleeder valve I21 is closed, the air temperature in the fixture II will rise and when it reaches the thermostatic cut-off point,

the thermostatic contact will be opened, the solenoid I5I de-energized and the plunger I53 restored into its uppermost position by the spring I55. This contact closing temperature will be below the temperature at which the refrigerating system will be cut-on by the pressure in the coil I2 as already described.

The cut-on point on the pressure control will be set on the screw II6 to obtain defrosting of the coils, but the cut-oil! point on the pressure control should be set very low by backing out thedifferential screw I46 to suit a heavy load. The

adjusting movement of the screw I46 may be V effected through the turning of the solenoid housing I50, which for that purpose is desirably calibrated and rigid with said screw I46. The screw I46 desirably has a triple thread in order to obtain a comparatively wide pressure range within less than one turn of said screw.

It may happen that the air temperature in the chamber II cannot be brought down to the ther- I plunger I53, having an enlarged soft iron head mostat closing point during an extra heavy load. However, the pressure in the coil I2 will come .down, so thatthe pressure control operating through contraction of the pressure diaphragm IIO will shut off the refrigerating system. This 'prevents continuous running of the refrigerating system and building up of a heavy frost layer during an extreme load, as would be the case if the thermostat I60 were the only means control ling the cut-off point.

Assuming that the thermostat I60 is set to close at 36 when this air temperature is reached, the bleeder valve I21 will be tripped into closed position by the downward actuation of the solenoid plunger I53 as already described. During the resultant off period, the air temperature in the fixture II will rise; and if the thermostat I60 has a differential of one degree, the thermostat I60 will snap open and the solenoid plunger I63 will be released when this air temperature reaches 37 F. When the coils I2 have defrosted and the pressure therein increased to the point where the pressure control cuts in, the air ten'iperaturev in the fixture I I will be at least a few degrees higher than the thermostat-openin temperature. This definitely prevents the solenoid plunger I53 from interfering with the opening snap movement of the bleeder valve I21.

If a thermostat with a wider differential of 3 'or 4 F. is used, the pressure control may want pressure in the coils I2 has been reached and the defrosting has been-completed on. each and.

every cycle.

The control operated from the diaphragm IIO has been described as being directly responsive to the pressure in the cooling coil I2. This pressure has a definite relation to the coil temperature. Therefore, as far as certain aspects of the invention are concerned, the diaphragm I I0 may be thermostatically controlled by the temperature of the coil I2. For that purpose, a thermal bulb charged with a suitable volatile fluid may be arranged in thermal contact with the coil I2, and may be connected to the diaphragm 0- by a tube to expand and contract said diaphragm in accordance with the temperature of said coil. Whether the diaphragm H0 is operated by pressure in the coil I2 or thermostatically, it operates according to the temperature of said coil.

or coil I2. is intended to cover both pressure and thermostatic type of control.

The pilot burner is constructed and ar-,-

ranged so that the main supply valve 03 of the control device 65 closes if for any reason the pilot flame is extinguished. The pilot burner I00 has avalve body comprising a bushing I10, threadedly secured in a valve casing I1I. Casing In is provided with an inlet passage I12 to which is connected the outletend of .the line I29 from the bleeder valve I21. The bushing I10 is formed.with a valve seat, I13 cooperating with a valve I14. Valve I14 is connected to a valve stem I15 which-passes through the bushing I10 and is secured to a snap-acting thermostatic diaphragm I16, clamped between the open end of a diaphragm housing I11 and a cover disc I18. A valve passage I80 formed in the bushing I10 communicates with one end of a conduit I8I leading to the burner 43.

A heat conductor. I82 is connected to the metallic disc I18, and is adapted to be heated by the pilot flame. When the pilot burner I is lit, heat is conducted by the heat conductor I82 to the thermostatic diaphragm I16. Under these conditions, the valve I14 will be open as shown in Fig. 2. When the bleeder valve I21 opens, bleeder gas from the control chamber 68 Will flow through passage I28, line I29, valve passages I12, I80, and conduit I8I to the burner.

If the pilot flame is extinguished, the thermostatic diaphragm I16 will snap into a reverse position from that shown in Fig. 2 to close the valve I14. Under these conditions, the opening of the bleeder valve I21 is not attended with lowering of the pressure in the control chamber 68, so that the main supply valve 83 will remain closed.

Various changes and modifications may be made within the scope of the forth in thefollowing claims.

What is claimed is:

1. In a refrigerator having a storage compartment cooled by an element of refrigerating ap-. paratus operated by a gas burner, a control for said burner including a first valve for starting invention as set and stopping flow of gas to said burner, a sec-' 0nd valve for causing operation of said first -va1ve, a first control element arranged to operate said second valve to start fiow of gas to said burner responsive to increase in temperature of said element and stop flow of gas to said burner responsive to decrease in temperature of said cooling element, and a second control element arranged to operate said second valve onlyin a direction to stop flow of g'asto said burner and responsive to decrease in temperature of air in said compartment.

2. In a refrigerator having a storage compartment and refrigeration apparatus including a 3. A refrigerator as in claim 2 in which said stop has an opening therein, and said movable part of said stop is movable into and out of said opening. r

4. A refrigerator as in claim 2 in which said stop is adjustable.

cooling element in said compartment, a device controlling operation of said apparatus including toggle mechanism movable in one direction to stop the apparatus and in another direction to start the apparatus, a stop for said mechanism having a movable part, a first element operative responsive to cha ge in temperature of s id cooling element to shift said toggle mechanism in both said directions, and a second ele-'- ment operative responsive to decrease, in temperature of air in said compartment'to move said movable part of said stop to shift said toggle mechanism in only said direction to stop said apparatus.

5. A refrigerator as in claim 2 in which said stop is adjustable and comprises a screw having a passage therethrough, and said movable part of said stop is a rod movable in said passage.

-6. A refrigerator including a cabinet having a storage compartment, heat operated refrigeration apparatus including an element for cooling said compartment, a fluid fuel burner for supplying heat for said apparatus, a device controlling operation of said fuel burner including mechanism movable in one direction to stop the burner and movable in the opposite direction to start the burner, a first element operative responsive to decrease in temperature of air in said compartment to move said mechanism only in said direction to stop the burner, and a second element responsive to'change in temperature of said cooling element to move said mechanism in both said directions.

'1. In a refrigerator having a storage compartment cooled by an element of refrigeration apparatus operated by a gas burner, a control for .said burner including a first valve for starting and stopping fiow of gas to said burner, a second valve movable in one direction for causing operation of the first valve to start said burner and I movable in the opposite direction for causing operation of the first valve to stop the burner, a first control element arranged to operate said second valve in said one directionto start flow of gas to said burner responsive to increase in temperature of said element and in said'opposite direction to stop flow of gas to said burner responsive to decrease in temperature of said cooling element, and a second control element arranged to move said second valve only in said direction to stop the burner.

8. In a refrigerator having a storage compartment and refrigeration apparatus including a cooling element in said compartment, a device controlling operation of said apparatus-includ-' ing mechanism movable in one direction to stop the apparatus and in another direction to start the apparatus, a movable member for adjusting said mechanism, a part mounted on and movable relatively of said adjusting member, a first element operative responsive to change in temperature of said cooling element to move said,

mechanism in both said directions, and a second element operative responsive to decrease in temperature of air in said compartment to move said movable part of said adjusting member to move.

said direction tofstop I said mechanism in only said apparatus.

. SVEN W. E. ANDERSSON.

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