US1529014A - Refrigerating apparatus - Google Patents

Description

March l0, 1925.

J, H. DENNE'IDY REFRIGERA'TING APPARATUS Filed ont. s1, 1924 s compressor condenser --expander t wherein the compressor is controlled in retothe pressure 1n the expander or spense Patented Mar. 1o,i925.

UNITED ASTATES PATENT orifice.

JAMES H. DENNEDY, 0F EVANSVILLE, INDIANA.

REFMGEBATING Arranarus.

Application filed October 31, 1924. Serial No. 746,919.

To all 'whom 'it may concern:

Be it known that I, JAMES H. DENNEDY, a citizen of the'UnitedStates, and resident of Evansville, in the county of Vanderburg and State of Indiana, have invented a certain new and useful Improvement in Rei'rigeratin'g Apparatus, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

My invention relates to refri erating apparatus and in particular to tgiiat type of system low pressure side. The chief object of my invention is 'to prevent the'overloadin of the compressorand the electric motor wich drives the'compressor, especially `when the system has `been allowed toA become warm and the pressure in the low pressure side has increased greatly above its normal operating pressures.

I accon'iplish this end by en'iploying a pressure reduci ion valve made a component part of a pre-ssiirie-controlled switch devicev which starts and stops the compressor `motor. VVith-this arrangment I need provide but a single spring pressed diaphragm elementlwhich serves for both the pressurecontrolled'switch mechanism land the pressure.. reduction valve. i

If a pressure reduction valve is inserted between the` pressure-control]ed switch and -the expandin,"r chamber, some means must be provided for preventing the pressure reduction valve from closing before the pressure on 'the switch has built up to the pre-A determined maximum for which it is set. Otherwise, although the pressure rises in the vexpanding chamber, the pressure-con-- -trolled switch would never be actuated because the pressure reduction valve would shut oif the pressure too soon. This danger can be avoided by so setting the v'pressure reduction valve that. it will be closed by a pressure somewhat higher than the maximum pressure for which thepressure-controlled switch is set, thereby providing 1a margin of safety of.Y for example, vtwo pounds. Anl object of iny invention is the reduction of this margin of; safety so that the maximumpressure which is ever admitted to the compressor is reduced sub- "will gradually .lowing description of one particular embodiment.

In the accompanying drawing, which illustrates this embodiment, I have shown somewhat schematically a refrigerating system, the lfloatcontrol forthe low pressure side, and also the valve and switch mechanism with which my invention is confurther objects and advantafgeis cerned, being shown in vertical section. The

high pressure side of the system comprises a compressor 10 driven by an electric' motor 11, an air-cooled condenser 12 and a iioat.

valve chamber 18 located within the refrigerated compartment 14, while the low pressure side comprises the heat absorbing coils 15 and the pressure-cdntrolled switch -unit 16 whichvopcns and closes the electric switch fluctuations'in the low pressure side caused by the temperature changes therein.

Vaporized refrigerant' is withdrawn from the low pressure side by the vcompressor 10 and discharged as compressed refrigerant to the coils of the condenser 12 where it condenses and flows to the float chamber 13. The high pressure of lthe uncondensed refrigerant in the condenser forces the condensed refrigerant upwardly throughthe' line 17 into the float chamber 13. As fast as the liquid refrigerant is delivered to the float chamber 13 the float valve 18 admits it into the low pressure side, the liquid first fiowing to the lower end of the header 19 of the heat absorbing coil 15. Whenthe compressor stops, following the pumping period, the pressure in the condenser 12 is .'at its maximum and substantially no more liquid refrigerant will be thereafter forced into the ioat cool oi. and lessen the pressurey therein. A substantial volume of liquid refrigerant is' maintained in the coil erant thereabove bears a definite relation to the temperature of the coil. This phase of the motor 11 in response to pressure chamber because the condenser and the pressure of the vaporized refrigof the system is more fully described in my co-pendmg application, Serial No. 521,427, tiled December 10, 1921. At the end of the pumping operation the coil 15 will be at. its lowest temperature which will be somewhat lower -than the temperature of the refrigerated compartment 14. The refrigerated compartment 14 may itself contain the perishables or other ultimate bodies to be refrigerated or may be one compartment of a refrigerator absorbin heat from other compartments throng the medium of a natural or forced flow of air; or the compartment 14 may be the cooling chamber in a brine circulating system.

From the top of the coil 15 a-line 20 leads back to the compressor. The pressure switch unit 16 is inserted in'this line and is responsive to the pressure therein. The 'mechanism is set to close the circuit of the motor 11 when the pressure in'the line 20 has reached a predetermined maximum for starting operation of the'compressor, and to open the circuit of the motor when the compressor has brought the pressure in the line 20 down to a predetermined minimum.

The valve and pressure-controlled portions of the switch mechanism 1'6 are carried within a cup-shaped casing 21. This casing has a chambered vertical bore 22 in its bottom which is intersected by a horizontal cross bore affording connections for the line 20. A bushing 23 'shouldered at its upper end to position it longitudinally of the bore is held with a drivin fit in the latter. The bushing has a plura ity of superposed slots 24 at its opposite sides communicating` with the connections with the line 20. A valve head 25 is reciprocably mounted with a snu fit within the bushing 23 and the valve hea has annular rooves 26 for matin the slots 24 of the bus ing. The reduced ower end of a shaft or piston stem 27 passes through the iston head 25 and is secured thereto,

T e sh-aft 27 carries a circular plate 28 which normall rests on the upper end of the bushing. the upper liange o the casin 21 and the cap member 30 of the switch unit. A fiexible metal bellows o`r sylphon 31 is disposed between the plate'28 and the ring 29, its ends being sealed to these respectlve members.

- The central opening of the cap member 30 is internally threaded to receive a plug 32 by means of which the pressure of the compression spring 33 interposed between it and the plate 28, may be varied.

Small relief ducts 34 lead from the upper and lower grooves 26 of the valve head into the spaces above and below the head to balance the valve. The grooves 26 in the head, it may be explained, are annular, while the slots 24 in the bushing extend through comparatively short arcs at the opposite sides rthecircuit of the motor.

rin 29 is clamped between.

of the bushing. When the grooves and slots are in registry as shown 1n the drawing, communication is established between the two sides of the line 20, but if the valve head 25 be moved upwardly a' fraction of an inch, the. grooves will move out of registry with the slots and4 effectively close communica# tion. .L

A duct 35 leads from the posterior side of the valve to the chamber 36 formed between the wall of the casing 21 and the sylphon 31 and also below the plate 28. When the valve head isin the position shown in the drawing the pressure in the line 20 willV be communicated through the relief duct 34 and the duct 35 to the bottom and the sides of the sylphon. When the pressure thus built up exceeds the vpressure of the spring 33 the platev28fwill be moved upwardly carryingr with it the shaft 27 and valve head 25.

The rise and fall of the shaft 27 actuates a snap-over switch mechanism 37. This switch, as previously stated, opens and closes However, I contemplate that the movement of the shaft 27 could controlsome other kind of mechanism for starting and stopping the effective operation of the compressor. I

The sylphon diaphragm and the means for varyine the spring pressure thereon are disclosed 1n further'detail and are claimed, in my co-pending application, Serial No. 571,680, filed July 29, 1922. and the particular form of switchmechanism I have shown here is of the type described in that application and also described and claimed in Patent No. 1,502,717 issued to me July 29, 1924.

In the preferred form of snap-over switch mechanism I have-shown a base 38 of suitable insulating material which is `held a spaced distanceabove the cap member 30 by studs 39. A pair of side plates 40 are ,mounted on the base and carry pivot pins 4l and 42 extending transversely therebetween. A pair of knife -arms 43 are pivoted on the pin 41 and carry at their outer ends knives or lll() blades 44 forming the movable contacts of the switch and adapted respectively to engage the stationary clips 45 secured to the ase 38. The inner ends of the levers 43 carry pairs of flanges 46 at their upper and lower sides. A yoke member 47 is pivoted on a fulcrum pin 48, the legs of vthe yoke member extendlng between the flanges 46 of the knife levers 43 to engage the flanges. The fulcrum pin is carried at the upper end of a link 49 mounted on the side plates by the previously mentioned pin 42. An :1c--

tuating lever 50 is pivoted on the pin 41 and provided with a slotted opening 51 through which the fulcrum pin 48 passes. Adjacent the slot 51 the free end of the actuating lever 50 pivotally supports a spring rod 52 passing at itsfree end through a suitable hole in the yoke and the actuating t i tends downwardly through a central open# tending either to Contact the upper ilang 50 levers 43 and drive the knives 44`into theirl tor being closed,

' 20 is brought i the shaft 27.

ing in the base 38. The lower end of the' lrod 54 and the upper end of theshaft 27 are adjustably connected by a left and right threaded nut 55.

When in the position shown in the drawing with the plate 28 in its lowermost` position, the switch knife 44,is held up by the yoke member which contacts its lower flanges, the yoke member being held against counter-clockwise rotation `by the upward kforce component of the spring 53. As the coil 15 absorbs heat 'from the compartment 14 the liquid refrigerant. in the coil ,will boil and thereby raise the pressure of the vaporized refrigerant in, the low pressure side. As the coil 15 continues to absorb heat the pressure in the line 20 will be built` up. This 4pressure is transmitted through the valve head 25 and into the pressure chamber 36. As soon as' the pressure in the chamber 36 over-balances the spring 33 the shaft 27 will move up-wardly.

The actuating lever 50 is swung upwardly lby the shaft 27 until the pivoted inner end' of the spring rod 52 comes to the center -line passing through the fulcrum pin 48 and the connection of the outer end of the rod 52 with lthe web of the yoke member During this much of the movement of the shaft 27 `the yoke member remains stationary and thus holds the knives 44 fixed in their open position; At such position, it should be noted, thespring 53 exerts no vertical component on the actuatingl lever to raise or lower the shaft 27.

A slight further upward movement of the shaft 27, however, will force the pivotal connection ot the spring rod past the dead center relation and the s ring 53 thereupon snaps the yoke member 4g' counter-clockwise es of the knife stationary clips'45. nThe circuit for the moin operation until the pressure in the line down to a` predetermined minimum. v

The trippingeof the snap-over-mechanism a's just descriy d gives a certain snap to the closingofthe valve also. The. spring A53, although disclosed as of small diameter, is comparatively a heavy spring and exerts considerable force. The force of fthe s ring is also multiplied by the leverage on .tlie shaft 27 gained by the actuatin lever 50. u-.The small vertical component of t e Spring 53 Vthus tends to a certain "extent to lift As the pressureA in thc line -the spring 33 he compressor will remainforces the plate 28 upwardly, the grooves 26 1n the valve head move almost out ot' registry with the'slots 24 by the time the dead center relation of the snap-over mechanism vis reachedd- When the switch mechanism f snaps over, the spring 53 will exert an added upward pressure on the shaft 27 as has just been explained. By suddenly adding this force'to the pressure of the refrigerant in the chamber 36, the plate 38 will be moved upwardly a slight distance against with the result that the groovesl ofthe valve head will move entirely'out` f registry with the slots in the valve bushing. y

The compressor will soon. bring down the pressure in and in the chamber 36. This will permit the valve head 25 to descend sufficiently to admit a little more vaporlzed refrigerant from the'anterior side of the line as needed to maintain the posterior` side ot' the line at fthe pressure for which the pressure-cow trolled device is set. When the pressure has been brought down to the predetermined Vminimum the spring 33 will verbalance the iuid pressure on the plate 28 and the shaft 27 will pull thev switch mechanism down past its dead center and snap it over to the open position shown in the drawing. The valve will then again be :fully open.

, .In the instance where the system is to be closed down, as for `repairs or because the refrigeration will not be required for some time, the line switch 56 will be opened so that when the pressure-controlled switch is snapped to its closed position the 'compressor will not be actuated. As the compart the line posterior to the valve ment 14 gradually warms up, the vapor presv sure in the coil 15 will reach a pressure many times'the normal operating pressure Whenit is desired to ut the system in o eration again, the switc 1 56 is closed and t e motor then starts the compressor. It

the compressor were not in some way 4pro-- tected against an excessive pressure in the line 20, it wouldbe drawing in refrigerant at a very considerable pressure and required to compress this refrigerant. "The pressure -of the charge drawn into the pump cylinders at such time would be so high that the small lmotor---which is snllicient only to carry the Vloadforordinary operation-would be en.-

s burn l in the line posterior to the valve, but the pipes are of small diameter' and the pressure-controlled switch located very close to the compressor in actual installation so that the volume of refrigerant pumped at the high pressure is practically negligible. The valve head 25 with its associated sylphon and spring 33 Will act as a pressure reduction valve to keep the pressure of refrigerant admitted to the compressor down to the seven pounds. In this way .the compressor is at all times protected against excessive pressures tending to overload the motor or cause a disquieting knock in the compressor.

While I have shown this particular embodimentpt'. my invention, I contemplate that changes mavbe made therein without departing from the spirit or scope of my invention.'

I claim: f"

1. The combination with a refrigeratingapparatus having a low pressure side including an expanding chamber and a high pressure side having a condenser, a compressor and a motor to drive the compressor, of a. pressure control device in the low pressure side between the expanding chamber and the compressor for starting and stopping the motor,.s`aid device comprising a spring-pressed diaphragm element subjected tothe pressure of the 10W pressure side, la switch mechanism actuated at predetermined points'by movement of the diaphragm elementI to open and close the circuit of the motor, and a valve member operated by the diaphragm element for regulating the flow of refrigerant from the expanding chamber to the compressor.

2. The combination with an artificial refrigerant-ing system consisting of a compressor, a condenser, and an expander, and an electric motor for driving the compressor, of a switch mechanism for opening and closing the circuit of the motor, apressurereducing valve between the expander and the.

compressor, and a diaphragm element subjected to the pressure in the expander, which diaphragm element actuates both the switch mechanism and the valve.

3. The combination with a refrigerating system having a heat absorbing expanding chamber, a' compressor pumping from the chamber, and a condenser, of a pressure# controlled mechanism ofthe spring-pressed diaphragm type subjected to the pressure ot' the chamberl for starting and stopping `operation of the compressor, a pressure-reducing valve of the spring-pressed diaphragm type between the chamber and the compressor, and a common member which correspondingly varies the spring tension for both the pressure-controlled mechanism and the pressure-reducin valve.

4. The combination with a refrigerating appa `atus havinga high pressure side including a compressor and a condenser, and a low pressure side forming a vaporizing chamber, and having a motor for driving the compressor, of an electric switch for starting and stopping the compressor motor, a pressure-reducing valve betvvem the chamber and the compressor, and :n element movable in response to pressure fluctuations in the chamber which controls both the switch and the valve.

5. The combination in a refrigerating system, of a vaporizing chamber, a compressor for withdra vingvaporized refrigerant therefrom, a conilenser, a motor for driving the compressor, an electric switch for starting and stopping the motor, a snap-over mechanism for opening and closing said switch, 'a diaphragm element subjected to pressure of' vaporized `refrigerant in the chamber, an actuating member secured to the diaphragm element and'connected with the snap-over mechanism, said mechanism,

when snapped by movement of the actuating member', imparting an additional force to the member a pressure reduction valve between the c amber and the compressor and also connected to the diaphragm element, the valve beine arranged to be finally closed by said additional movement of the member imparted by the snap-over mechanism.

6. The combination With a refrigerating apparatus consisting of a compressor, a condenser, and an evaporator and a motor for driving the compressor,'of a combined pres` sure-controlled switch for controlling the motor and pressure reduction valve between the evaporator and compressor, comprising a casing forming a pressure chamber, a. diaphragm forming a Wall of the' chamber, a spring for the diaphragm, a stationary valve port formed in the casing, a movable valve element for cooperating with .said port connected to said diaphragm, a svvitch mechanism supported on said casing and connectedvwith the diaphragm to be operatedthereby, inlet and outlet passages in the casing communicating with the evaporator and the condenser, respectively, and means for adjusting the pressure of the spring.

f7. The combination with a refrigerating apparatus consisting of a compressor, a condenser, and an evaporator and amotor for driving the com ressor, of a combined pressure-controlle switch for. controlling the motor and pressure reduction valve be'- tween the evaporator and compressor, comprising a casing forming a pressure chamber, a diaphragmforminrr La Wall of the chamber, a spring for the iaphragm, a stationary valve port formed in the casing, a movable valve element for cooperating with said port connected to said diaphragm, a switch mechanism supported on said casevaporator and the compressor, respectively,

means for adjusting thev pressure of said spring, and an adjustable actuating-member connecting the diaphragm and switch.

8. In a refrigerating.;` system,v the combination of a vaporizing chamber, a compressor for withdrawing vaporizing refrigerant therefrom, a condenser, an electric motor for driving: the compressor and a unitary pressure-controlled.switch and pressurereducing valve comprising a casing forming a pressure chamber, a spring-pressed diaphragm element constituting a Wall of the chamber, a bore in the casing, avalve head reciprocably mounted therein, inlet and outlet ports in the opposite sides of the bore, a passage in the head for registering with the ports, the head being connected to the diaphragm element for 'reciprocation thereby, discharge means connecting the Vaporizing chamber and the compressor with the inlet and outlet ports, respectively, said chamber being in communication .with one of said discharge means, a switch for opening and closing the circuit of the motor, a snap-over mechanism mounted on the casing for controlling the switch, an actuating member for the snap-over mechanism connected with the diaphragm. element, and means for adjusting said member. the valve head being set relatively to the diaphragm element to close communication between the ports only aiter the pressure in the chamber has risen above the maximum pressure for which the snap-over mechanism is set to operate the switch,

In Witness whereof, I hereunto subscribe my name thisV 27th day of October, 1924.

JAMES H. DENNEDY. Witnesses:

LUCY BUTTRUM, F. W. BECKER.

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