US2214298A - Refrigerating apparatus - Google Patents

Description

Sept. 10, 1940. lLBERT, SR 2,214,298

REFRIGERATING APPARATUS Original Filed May 24, 1.955 2 Sheets-Sheet I p 10, 1940- W., GILBERT. S R

REFRIGERATING APPARATUS O'rigina; Filed May 24, 1935 2 Sheets-Sheet 2 Patented Sept. 10,1940

UNITED STATES PATENT orFicr:

REFRIGERATING APPARATUS Walter Gilbert, Sn, Johnstown, Pa", assign'or of one-half to Ernest F. Walker, Johnstown, Pa.

Original application May 24, 1935, Serial No. 23,320. Divided and this application May is,

1937, Serial No. 142,921

2 Claims.

This application is a division of my copending application, Serial Number 23,320, filed May 24, 1935.

This invention relates to a refrigerating system,

5 and more particularly to a multiple system or system employing a plurality of cooling units operating at different temperatures for suppyling the required amount of refrigeration, such cooling units being supplied with refrigerant from a 10 single compressor condenser unit.

The invention may be utilized for example in an installation having a low temperature cooler to be maintained at a temperature at or below F. and a display counter to be maintained at a temperature above freezing point, although it is not limited to systems of this character.

' It is an object 01' the invention to provide improved control means for the cooling units for independently regulating the refrigerant supplied to each cooling unit by means of snap action thermostatically controlled expansion valves or the likeand with additional means for preventing temperature equalization of the several cooling units by the flow of fluid from one to the other.

35 A further object of the invention is to provide a thermostatic expansion valve and operating mechanism therefor of improved construction and operating characteristics.

Other objects and advantages of the inven 30 tion will appear from the following description of the embodiments thereof shown in the accompanying drawings, wherein:

Fig. 1 is a detail view partly in section of one form of the expansion valve embodying the ina vention;

Fig. 2, a fragmentary sectional view of a modified form of expansion valve, and

Fig. 3, a diagrammatic view of asystem in which the valves shown in Figs. 1 and 2 may be employed.

Referring to'Fig. 1 of the drawings, an expansion valve embodying the invention comprises a hollow, generally cylindrical sleeve member Ill provided with an extension or boss I l at the upper 45 end and closed at the lower end by a cap member l2 secured thereto in any desired manner, as by means of the bolts l3. Bracket members I4 and l5, depending from the sleeve member are also clamped thereto by the bolts l3. An insulat 50 ing disk I6 is secured to the lower ends of the bracket members I4 and I5, as for example by 7 screws l8 threaded into the valve housing H.

An expansible bellows 2,!) is clamped between the cap member I2 and the sleeve I0 and serves 55 to seal the space 2| inside of the sleeve Ill. The

space 2| is in communication through a length of tubing 22 with a capsule 23, the space 2|, tubing 22 and capsule 23 being filled with an expansible fluid whereby the pressure exerted on the bellows member is dependent upon the temperature to 5 which the capsule 23 is subjected. The capsule 23 is positioned within or adjacent the refrigerating element or expansion coil of the refrigerating system in order to control the expansion valve in accordance with the temperature of the re- 10 frigerating element, as will be described hereinafter.

A piston 25 having a shank portion 26 surrounding a piston rod 21 is disposed within the bellows member 20 to be actuated upon an increase in pressure within the sleeve member ID. The movement of the piston '25 is resisted by a coil spring 28 arranged between the shank portion 26 of the piston and the threaded shank portion 29 of the thumb screw 3|) threaded into the cap 20 member l2. The piston 25'is biased by the spring 28 in an upward direction, the tension of the spring being adjustable by means of the thumb screw 30. A reinforcing sleeve 3| may be provided adjacent the bellows 20 and surrounding the spring 28 to prevent buckling of the bellows member. A pointer 32 cooperating with the thumb screw permits the same to be calibrated in terms of operating temperatures.

A bldck as is secured on the piston rod 21 as 80 for example by means of clamping nuts 36 threaded on said rod. The block is.notched to form bearings i'orthe knife edge links 31 and 38 forming a toggle link. The outer ends of the toggle link members 31 and 33 engage bearings in the supporting arms 39 and 40, the arm lll being piovted at 4| to the bracket member H. The toggle link comprising the members 35, 31 and 38 is for the purpose of imparting a snap action to the thermostatically controlled member of the 40 35 past the dead center of the toggle. The critical temperature at which the thermostat will operate to effect movement of the valve operating rod 21 is adjusted by means of the thumb screw 30, in

accordance with the calibration thereof or the u indications of the pressure gauge 24, whereas the difference between the actuating and restoring temperatures of the thermostat mechanism is mechanism is adapted to engage the valve opcrating plunger 41 which is slidably mounted in the insulating disk I5 upon an increase in the temperature to which the capsule 23 is subjected which causes an increase in the pressure upon the piston 25 of the thermostat. The plunger 41 is operatively connected to a lever 48 pivoted at 49 within the valve housing I! andhaving depending arms 50 engaging the head 5| of the expansion valve member 52. The valve member 52 is slidably supported in the valve housing and is normally biased to a closed position against 52 and 53 and adapted to be connected to the condenser or other source of refrigerant. The interior of the valve housing is connected through a pipe connection 55 to the refrigerating element or expansion coil with which the capsule 23 is associated. Inspection of Fig. 1 of the drawings discloses that the internal diameter of the pipe 55, connecting the expansion valve housing with the refrigerating element or expansion coil, is substantially the same as the internal diameter of the expansion valve orifice which adjoins the valve seat 53. This special designretards premature expansion of the refrigerant medium; that is, it retards expansion of the refrigerant medium prior to its reaching the refrigerating element or expansion cofl. This arrangement also makes for the elimination of frosting about the valve housing and permits installation of the entire evaporator assembly on the exterior of thecabinet to be refrigerated. The valve housing I9 is sealed at the top by a flexible diaphragm 58 clamped underneath the insulating disk l5.

It will be apparent that upon an increase in the temperature to which the capsule 23 is subjected, a pressure is built up in the thermostatic element and the piston 25 is actuated thereby to throw the toggle 35, 31, 38 to the position shown in dotted lines in Fig. 1 and open the expansion valve 52, 53 to admit refrigerant to the cooling coil. As the temperature of the cooling coil is lowered, the pressure in the capsule 23 decreases and at a predetermined temperature, the spring 28 restores the operating rod 21 to its initial position, thereby permitting the expansion valve to be closed by the spring 56 cut off the supply of refrigerant.

As shown in Fig. 2, the details of construction of the thermostatic mechanism may be varied without departing from the scope of the invention. In the construction shown in Fig.2, the bellows member 23 is replaced by an equivalent pressure-responsive construction. In this modification the thermostatic mechanism comprises a housing formed by the cap members 50 and 5|. A diaphragm 62 corresponding to-the bellows member 20 of Fig. 1 is clamped between the cap members 50 and 5|. The space above the diaphragm 52 is in communication with a capsule located in or adjacent the cooling coils through the passage 53 and tube 54. The operating rod 55 for the expansion valve is secured to the diaphragm 62 by means of the clamping members 66, whereby the rod is actuated in response to changes in pressure to which said diaphragm is subjected. The movement of the piston rod 85 is opposed by the spring 31, the tension of which is adjusted as desired by means of adjusting screw 68. The expansion valve which may be similar to that shown in Fig. 1 and the toggle link snap-acting mechanism may be supported upon the depending brackets 69 and I0, corresponding to the the members I4 and I5 in Fig. 1.

The snap-acting thermostatic expansion valve described above is designed for use in multiple refrigerating systems such as that shown diagrammatically in Fig. 3. The system shown in Fig. 3, by way of example, comprises a compressor H, a condenser 12, a liquid receiver 13 and a plurality of refrigerating elements or expansion coils 14, 14a. and 1421 connected in multiple to the receiver 13. Expansion valves I5, 15a and 1512 are connected to control the supply of refrigerant to the respective cooling coils, the expansion valve being of the construction shown in Fig. 1 or Fig. 2. By regulating. these valves by means of the adjusting elements 30 and 43, the temperatures of the cooling coils may be separately controlled and maintained between any desired limits, whereby a temperature may be maintained in one refrigerating compartment at or below 0 F. and in other compartments at the same or different temperature, all of the cooling coils being supplied from a single compressor unit. Check valves 15, 15a and "b are preferably provided between each of the cooling coils 14, 14a. and 14b and the suction connection 11 of the compressor II.

In a ystem embodying the invention two or more I rigerators or evaporators may be maintained at separate or individual temperatures according to the requirementsof each refrigerator while all of the refrigerators may be supplied from a single condensing unit or compressing unit. The snap-acting thermostat control automatically maintains the desired temperature in each refrigerator without attention or supervision and by reason of the particular construction of the snap-acting mechanism, a positive operation of the expansion valves is insured at all times.

Various modifications in the specific construction and arrangement of the valves shown may occur to those skilled in the art and are deemed to come within the scope of the invention it valve to open when the temperature of said 0001- ing unitreaches a predetermined maximum and cause said snap acting valve to close when the temperature reaches a predetermined minimum.

suction lines from each of said evaporators connected with the suction side of said compressor, one-way valves disposed in said suction lines for preventing a back and interflow of refrigerant to and between any and all of the said evaporators by reason of back pressure in the suction lines, and as and for the purpose de scribed said expansion valves constituting the sole expansion means between the condenser and each of the evaporators.

2. A refrigeration system comprising a compressor-condenser unit, a plurality of cooling units, a liquid line having connections for supplying refrigerant from the compressor-condenser unit to each of the cooling units, a. return line to the compressor-condenser unit having connections with each of the cooling units,

a snap acting expansion valve in the supply lines to each of said cooling units for independently controlling the supply of refrigerant to each cool ing unit, said each snap' acting valve being adapted, constructed, and arranged to open in response to a predetermined high temperature and close in response to a predetermined low temperature, and a check valve in the suction line leading from each cooling unit for preventing return of refrigerant into the respective cooling units from the suction line and thereby equalizing or otherwise afiecting the temperature of the cooling units said expansion valves constituting the sole expansion means between the condenser and each of the evaporators'.

. WALTER GIIBERQT, SR.

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