US1618815A - Refrigerating system and appliance - Google Patents

Description

R. C. CORY ET AL REFRIGERATING SYSTEM AND APPLIANCE Feb. 22, 1927.

Filed Aug. 11, 1922 gig 4. .42

\\\\A F0 a a W 59 w JAM 5W Patented Feb. 22, 192 7. I UNITED STATES 1,618,815 PATENT OFFICE. 1

.RU'SSELL 0. com! AND GHARLESM. TERRY, or CHICAGO, rnnmorsassronons r 1;. w. CASH COMPANY, A conronnrron or nnmwm.

REFRIGERATING SYSTEM AND APPLIANCE.

Application filed August 11, 1922. Serial No. 581,144.

This invention relates to refrigerating systems, and has for its general object to pro vide a system of high operating economy, or minimizing the horsepower consumption per 5 ton of refrigeration. More specifically, an

object of this invention is to provide in connection with an expansion valve of refrigerating systemsfassociated'control means for "automatic variation of the valve setting ac- 0 cordantly with the temperature .in the area to be refrigerated sothat at all times the temperature of the refrigerant in flow through the coils may be so related to the temperature of the medium to be cooled as 5 to secure, or to approximate, maximum-efficiency conditions for heat absorption.

Another object of this invention is, to provide simple, desirableand effective valving means and control means for the stated oper- 0 ations; and other and further object of said invention will become apparent from the following description taken in conjunction with the accompanying drawings.

In the drawings, Fig. 1 is a diagrammatic 5 illustration of a refrigerating system embodying our invention; Fig. 2 is a vertical section through .a valve therefor, taken on refri crating systems employing the stated,

or ot er, refrigerants In the "drawings indicates the refrigerating coil within the area 'A to be refrigerated, and as typifying generically known practice and apparatus, a suitable constantspeed positive pump 11, driven by a suitable prime moversuch as an electric. motor 12, may withdraw the gaseous refrigerant, such as anhydrous ammonia, from the coillO and pump it to ghe condenser 13,. illustrated as of simple, w ter-cooled type, so that the refrigerant will be liquefied and forced under suitable pressure (say 180 pounds to 200 pounds per square inch, for example) into the receivin tank-14. Fromthe receiving tank the liquid refrigerant is permitted to pass to the refrigeratingcoil 10, through an expan'sion valve, generally indicated at 15, this valve ofiering an escape-we so restricted that the pressure in the re igerating, coil is always low as compared with the iquid pressure, and therefore the refrigerant may resume its gaseous state in the coil and ab-' sorb heat from the coil-surrounding medium to be cooled. 1

Expansion valves as commonly employed are of pressure-reducing type intended to maintain constant the ressure-conditions in the refrigerating coil, t e constant low ressure being fixed at a value consistent wit the lowest temperature whichit'is desired to attain and maintain'in the area A. This low pressure is hereinafter termed the suction pressure, as it is approximately the pressure that exists at the suction intakeof the pump.

The improved system provides for automatic adjustment of the expansion valve to vary the suction pressure in general accord with variations of temperature in the medium to be cooled, that is to say to permit a rise in suction pressure within the coil 10 .as tema perature of the area A rises, and a decrease in said suction pressure as the temperature of area-A decreases. This automatic variation of valve-setting is advantageous. Most economical absorption of. heat takes place a when the difference in temperature between the refrigerant-filled coil and the surrounding medium to be chilled is about 15 degrees F. Bythe use of this invention provision is madefor maintaining approximately this temperature-difference overa wide range of.

temperature-variation of the medium to be cooled It will further be understood that the temperature of the refrigerant in the coil 10 varies with its pressure, .a higher refrigerant-temperature being a concomitant.

of higher suction pressure, and vice versa.

Also, it may be pointed out, the higher is the pressure of the ammonia gas 1n coil 10, the greater is its density, from which it follows that a constant speed compressor 4.

will handle a greater amount of ammonia gas when operating at high suction pressure that when operating at a lower suction pressure; and of course, the greater the amount of ammonia compressed the higher is the refrigeration-capacity developed.

' In the preferred'ar'rangement shown for embodying the invention, the valve proper,

l6, coacts with a port 17 the partition 18 of valve casing 19 to control the flow from inlet chamber20 (connected to the yond this diaphragm is a controlv chamber 24 the pressure in Which varies with temperature changes in room or area A. Thus, control chamber 24 may be connected by pipe 25 to a receptacle 26 to form a sealed thermostatic system containing an expansible medium, such as a body, 27, of liquid that volatilizes to develop higher pressures at higher room temperatures throughout the expected range of operation. Such materials as sulphur-dioxide, ethyl-chloride, and the like may be used, or ammonia may be employed in the thermostatic system. In

general, it will be apparent, as the temperature in area A rises the pressure in the sealed thermostatic system will increase in a determinable ratio of values, and this varying pressure will open the valve against its mechanical loading until the pressure in the delivery chamber or suction pressure, coact ing with the spring loading, establishes a balance of pressures acting oppositely on the diaphragm. It will be seen, therefore, that as room-temperature in the area A fluctuates, so will the suction pressure, and concomitant temperature of the refrigerant in coil 10, fluctuate in like direction.

The valve-closing spring is preferably made adjustable as to tension, and may be adjusted to balance a desired pressure difference between the pressure in the thermostatic system and the pressure in the refrigerating coil. It is usually desirable to maintain a pressure diflerence 'between the thermostatic system and the refrigerating coil.

corresponding with a temperature difference of approximately 15 degrees, and although with an ammonia refrigerant curves of pressure change and temperature change are not identical or indicative of a constant ratio, the valve construction shown, and employed as described, may be made to regulate the suction pressure or pressure in the ex ansion coil 10 in nearly-ideal proportion to t e tem perature-indicating pressures of the thermostatic system throughout the expected range of operations.

To clarify the operation of the system, let it be assumed that the desired roomtemperature at A is 20 degrees F., and that with this low temperature prevailing, the thermostatic pressure exerted in the control- ,of the valve only suflicientl ling chamber overcomes the spring loading to maintain the suction pressure in the re rigerating coil at a point consistent with a 5 degree F; temperature of said coil. If, now, a charge of warm material be introduced into area A, raising the room temperature to say 50 degrees, the increased pressure engendered in the thermostatic system forces open the expansion valve to greater extent, permitting the pressure in the expansion coil to rise to a value preferably sufficient to enable the refrigerant to develop a temperature close to or somewhat above 35 degrees F. so maintaining the refrigerant approximately" at or slightly above the temperature for maximum heat absorption under the newly established conditions. As the room temperature is brought down, the valve gradually closes toward initial position, tending substantially to maintain the desired relativity of the temperature affecting the thermostatic system and the temperature existing in the coil. As a power-saving factor this self-regulation is highly beneficial. At the higher suction pressure developed commensurately with increased room temperature, the power requirement for compres-- sion of the gas. obviously is markedly reduced, the capacity of the machine in tons I per horsepower being more than doubled under the conditions given by way of example. Further, this increase of capacity of the machine occurs just when it is most needed, that is, when the temperature 'of the medium to be cooled is highest, and therefore the lowering of the room temperature to the desired level may be most rapidly accomplished.

Details of construction and arrangement 'may be widely varied within the broader aspects of the invention, but in its commercial practice it is preferable to employ the advantageous valving mechanism in s ecific formas illustrated in the drawings.

he valve proper 16 may be of piston form working in the demountable cylinder 29 j which is held in tight connection with the aperture in the partition 18 by the threaded retaining head-30. This cartridge mounting of the valve mechanism proper is commercially known and needs no detailed description. A light spring 31 tends to close the valve, constantly. holding the extension end 33 of the valve in contact, .beyond the ort, with the operating lever v34 which is ocated in the delivery chamber. This lever, of bar form, may rock on its appropriately rounded fulcrum surface 35 at one end; engages a positioning pin 36 on the partition wall, makes substantially point-contact at 37 in alignment with valve extension 32 and the center of diaphragm 23, with the ressure distributing saddle 38 directly underlying said diaphragm; and at its remote extremity receives the pressure of the valve-closing spring 22. Spring 22 is preferably arranged in a pocket 39,0f the delivery chamber and bears at its bottom on the spring plate 41 which is vertically adjustable by an externally accessible screw 42 working through a packing gland 43 at the bottom of the pocket. Manifestly movement of the valve lever 34 accordantly with diaphragm position will act through valve extension 32 to force the valve open or permit its closure.

The automatic operation of the system hereinbefore described may advantageously be furthered by controlling the operation of the pump 11 to stop its working whenever the temperature 111 area A reaches a predeter mined minimum, and to this end is connected to the pipe a chamber 45 having a buckling diaphragm :tti carrying the movable contact of aswitch 47 that controls the motor operation. This control may be exercised through a suitable relay switch 48 in known fashion, if desired.

'e claim:

1. A regulator for a refrigerating apparatus comprising a casing having an inlet chamber and a delivery chamber, a diaphragm dividing said delivery chamber to form a control chamber, means for delivering fluid pressure to said control chamber a valve for controlling the passage of the refrigerating medium from said inlet chamber to said delivery chamber, a spring tending normally to close said valve in opposition to the fluid pressure in said control chamber, and additional spring actuated means for regulating the action of the pressure in said control chamber independently of the action of said valve.

2. A regulator for a refrigerating appara tus comprising a casing having an inlet chamber and a delivery chamber, said casing having also a control chamber, adiaphragm separating said delivery chamber from said control chamber, a valve for controlling the passage of the refrigerating medium from said inlet chamber to said delivery chamber, a spring tending to close said valve, a lever interposed between said valve and said diaphragm, said valve having an extension engaging said lever whereby the pressure in said control chamber tends to open said valve against the pressure of said spring, independent actuating means engaging said lever and means for adjusting said actuating means to regulate the pressure required in said control chamber to open said valve.

3. A regulator for a refrigerating apparatus comprising a casing having an inlet chamber and a delivery chamber, said casing having also a control chamber, a diaphragm separating said delivery chamber lrom said control chamber, a valve for controllingthe passage of the refrigerating medium from said inlet chamber to said delivery chamber, a spring tending to close said valve, a lever interposed between said valve and said diaphragm, said valve having an extension engaging said lever whereby the pressure in said control chamber tends to open said valve against the pressure of said spring, a spring engaging said lever, and means for adjustin said spring to regulate the pressure requiret in said control chamber to eifect the opening of said valve.

4. A regulator for a refrigerating apparatus comprising a casing having an inlet chamber, a delivery chamber and a control chamber, a partition separating said inlet. chamber from said delivery chamber and having a passage therethrough, a valve for closing said passage, means tending normally to close said valve, a lever pivoted on said partition, an extension member extending between said valve and said lever, a saddle contacting with said diaphragm and engaging said lever opposite said extension member, whereby the pressure in said control chamber tends to open said valve in opposition to said spring, a second spring engaging said lever on the side thereof opposite said diaphragm, and means for regulating said second named spring.

RUSSELL C. CORY. CHARLES M. TERRY.

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