US1982668A

US1982668A - Refrigerating apparatus

Info

Publication number: US1982668A
Application number: US518709A
Authority: US
Inventors: Rasmus M Hvid
Original assignee: Frigidaire Corp
Current assignee: Frigidaire Corp
Priority date: 1931-02-27
Filing date: 1931-02-27
Publication date: 1934-12-04
Anticipated expiration: 1951-12-04

Description

mac. 4, 1934. R M HVID 1,982,668

REFRIGERATING APPARATUS Original Filed Feb. 27, 1931 Patented n... 4, 1934 UNITED STATES 1,982,668 REFRIGEBATING APPARATUS Basmus M. Hvld, Chicago, assimito Frigidaire Corporation, Dayton, Ohio, a corporation of Delaware Application Rffibfllnry 27, 1931, Serial No.

owed November 1, 1933 My invention relates to mechanical refrigeration and particularly to a novel arrangement and apparatus similar to that disclosed in mycopending applications, Serial No. 499,753 filed De- 5 cember 3, 1930 and Serial No. 513,374,1iled February 4, 1931.

The development of refrigerating apparatus has resulted in a degree of perfection in which little or no mechanical trouble may reasonably be expected over a period of years. This, however, does not include the provisions for making and breaking contact of the motor circuit by the automatic regulating apparatus. During normal operation, the motor operating circuit is made and broken a multitude of times, and,- in the course of time, the contact points become oxidized or are likely to fuse, resulting in misopera-' tion. Furthermore, the cost of the switch mechanism is considerable.

I have, therefore, conceived it not only possible but desirable to employ a constantly running motor-compressor. Such .a motor-compressor is thoroughly practical, and, when suitable provision is made for lubrication, will run indefinitely.

2 However, in order to insure efllcient refrigerating action some means are necessary for controlling the compressor output, not only in order to maintain a fairly constant temperature, but to reduce current consumption. This I accomplish by providing a thermostatically controlled by-pass valve so arranged that when the temperature adjacent the evaporator reaches a predetermined point, the valve will operate to relieve the compressor of load; in other words, to directly connect the inlet and outlet of the compressor.

Furthermore, this is accomplished in such a manner that a portion of the condenser is utilized for a certain degree of cooling of the short circuited gas. In the arrangement shown, the result is accomplished without measurably lowering the pressure in the high side and without interference with the pressure or temperature conditions in the evaporator.

The invention will be more readily understood an ordinary box 10 having an opening in arear wall thereof. Within the opening the refrigerating unit is mounted for convenient insertion or by reference to the accompanying drawing, in

, 11 Claims. (01. 62-115) removal. The unit comprises an evaporator 11 of common form, containing a float 12 controlling an inlet valve 13, for condensed liquid. An outlet pipe 14, for gas leads to the intake of the compressor. The motor-compressor unit, indicated w generally by the numeral 15, is of the form illustrated in detail in my co-pending application, Serial N 0. 499,753 heretofore identified. This unit contains a constantly running motor and a compressor within the limits of the armature of the motor. The intake pipe 14 for the compressor contains a check valve 16, the function of which will be hereafter described, the pipe' being formed in a coil as at 17, to provide a resilient support for the motor compressor unit. The outlet pipe from the compressor is also formed in a coil as at 18 at the top of the unit, the pipe leading to the inner coil 19 of the condenser. The outer coil of the condenser terminates in the pipe 20 which extends directly to the inlet valve 13 of the evaporator.

The motor-compressor and other parts hereafter described, are contained within a doublewalled shell, the outer and

inner walls

21, 22 being separated by suitable insulation 23 or by so providing a vacuum. The shell is open at its backside in order that the heat generated by the motor may be dissipated by the circulation of air through the open side. The top and bottom walls of the inner shell 22 are somewhat in- 35 clined outwardly in order to facilitate circulation. The evaporator is supported on the outer shell by the lugs 24. The condenser is located in a vertical plane alongside of the wall of the box, and when the box is located adjacent to a building wall 25, a strong upward movement of air will efficiently cool the coils.

The by-pass valve, best shown in Fig. 2, is of simple construction, very small in size and is arranged alongside of the motor compressor 15 within the cavity of the shell. The mechanism includes a head 26 containing a valve seat 27 and

pipe connections

28, 29. The pipe 28 extends upwardly and connects with one of the outer coils 1 30 of the condenser. The pipe 29 extends to the inlet pipe 14 to the compressor at a point below the check valve 16.

The valve-casing includes a cup 31 having screw, threaded engagement with the head 26. Within the cavity of the cup is mounted a large bellows 32 at its bottom in open communication with a thermostatic tube 33, the bottom resting on the floor of the cup 31. The upper end of the bellows is soldered to a head 34 having a de- 119 pressed central portion 35. This depressed portion contains a coil spring 36 engaging against a disc 3'7 soldered to the valve stem 38. The head 39 of the valve cooperates with the valve seat 2'1. A small bellows 40 seals the valve stem from the outside atmosphere, the inside of the bellows 40 being open through the passage 41 to the pressure in the

pipes

28, 29. By the selection of a certain refrigerating gas,'the thermostatic element may be eliminated as the vehicle for temperature control. In'that case, a tube corresponding to the thermostatic tube illustrated herein, will merely be connected to the low side, and the pressure of the gas in the low side may be used to act on the by-pass bellows, to effect the opening and closing thereof in the same manner as described herein concerning the static operation.

The operation is as follows:

In normal operation, when the temperature of the evaporator is reduced to a predetermined point, the thermostatic liquid in the tube 33 will also be lowered in temperature, thus reducing the pressure within the.bellows 32. The high pressure acting on top of the valve head 39 will now be sufllcient to overcome the resistance offered by the bellows 32 and the valve head 39 will open slightly. Immediately the high pressure effective in the condenser will enter the space past the valve through the passage 41 and into the bellows 40. This will result in an instantcomplete opening of the valve 39. With the valve 39 open, the gas discharged from the compressor will be delivered intotwo of the coils of the condenser, thence through the pipe 28 past the by-pass 39, into the pipe 29, thence into the intake pipe 14 back to the compressor. Due to the check valve 16 no pressure is permitted to enter the upper part of the pipe 14 or the evaporator. If the level of liquid in the evaporator is lowered at such periods, the condensed liquid remaining in the condenser will be delivered into the evaporator in the usual manner, as the pressure in the condenser is not materially lowered by action of the by-pass valve. Furthermore, the use of a part of the condenser for circulation of the moving by-passed gas results in a degree of cooling that will serve to keep down the temperature of the compressor during idle operation. By utilizing the upper sections of the condenser for this circulation, I avoid the possibility of withdrawing liquid into the compressor during idle operation. f

When the temperature raises in the evaporator, the described operation will be reversed and the valve 39 closes. Normal operation will then proceed as before. Inasmuch as the valve 39 will be closed slowly, the motor will be reloaded gradually and there will be no sudden pronounced increase in the power consumption.

.The form of the thermostatic control is unimportant, the illustration being in a sense diagrammatic. Neither have I illustrated any means for manual adjustment of the temperature conditions, this being an unimportant detail. I may also see fit to suitably insulate the thermostatic tube where it is in the motor compressor area.

It will be understood also that the form of the by-pass valve is not important, so far as the broad idea is concerned, the thought conveyed by this disclosure being that of suitable means for unloading and reloading the motor-compressor, the motor being continuously operated.

These and other details herein disclosed may be evaporator, and thermostatically thermovaried within wide limits without departure from the spirit of my invention.

I claim:

1. In refrigerating apparatus, the combination of a constantly running motor, a compressor, a condenser and an evaporator, and means controlled by the temperature condition of the evaporator for unloading and reloading the motor whereby to maintain a uniform temperature.

2. In refrigerating apparatus, the combination of a compressor, a continuously running motor for actuating the same, a condenser and an controlled means for interrupting compression of gas by the compressor when the evaporator has a predetermined temperature.

3. In refrigerating apparatus, the combination of a compressor, a continuously running motor for actuating the same, a condenser and an evaporator, and thermostatically controlled means for unloading and reloading the motor according to the temperature of the evaporator.

4. In refrigerating apparatus, the combination of a compressor, a continuously running motor for actuating the same, a condenser and an evaporator, and thermostatically controlled means for by-passing thegas discharged from the compressor into the intake of the compressor at a pressure above the pressure in the evaporator when, the evaporator reaches a predetermined temperature.

5. In refrigerating apparatus, the combination of an evaporator, a continuously, running motor, a compressor, a condenser having surfaces at diiferent vertical elevations, a thermostatically controlled valve, and pipes, the passage of gas through whichis controlled by said valve, for bypassing gas fronr the compressor outlet through an upper portion of said condenser and then to the compressor inlet.

6. In refrigerating apparatus, the combination of an evaporator, a continuously running motor, a compressor having condensing surfaces at different vertical elevations, a thermostatically controlled valve, and pipesthe passage of gas through which is controlled by said valve, for bypassing gaTs from the compressor outlet through an upper portion of said condenser and then to the compressor inlet, and means for maintaining normal high pressure conditions in said condenser during said by-passing operation.

I. In refrigerating apparatus, the combination of a compressor, a continuously running motor for actuating the same, a condenser and an evaporator, and thermostatically controlled means for unloading and reloading the motor according to the temperature of the evaporator, and means for maintaining normal pressure conditions in the condenser during by-passing operation.

8. In refrigerating apparatus, the combination of a compressor, a continuously running motor for actuating the same, a condenser and an evaporator, a by-pass valve for unloading and reloading said motor, a thermostat for operating said valve, said thermostat being responsive to evaporator temperature and operating to gradually operate the valve to provide for gradual reloading of the motor.

9. In refrigerating apparatus, the combination of a compressor, a continuously running motor for-actuating the same, a condenser and an evaporator, and thermostatically controlled means for unloading and gradually reloading the of compressing and non-compressing operation,

an evaporator and a condenser, a portion oi. said system being a high pressure side and a portion of said system being a low pressure side, means for subjecting the piston of said compressor to only one of said pressure sides during a portion of the operating cycle including a plurality of piston strokes and a check valve on the low pressure side of said system for preventing high pressure from saidhigh pressure side from entering the evaporator during said portion of the cycle.

RASMUS M. HVlD.