US1786791A

US1786791A - Refrigerator equalizer valve

Info

Publication number: US1786791A
Application number: US222598A
Authority: US
Inventors: Matson C Terry
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1927-09-28
Filing date: 1927-09-28
Publication date: 1930-12-30
Anticipated expiration: 1947-12-30

Description

D. 3o, 1930. M. c.. TERRY 1,786,791

REFRIGERATOR EQULIAZEH VALVE:

Filed sept. 28. 1927 2| 22 'sTARTmG/ RuNNlNG wlTNl-:ss x25 Nln/(lrqfm u n Y ell-ry d Fuel, BY l www ATTORNEY Patented Dec. 30, 1930.

UNITED STATE-s PATENT orar-'ICE HATSON C. TERRY, OF HANBFIELD, OHIO, ASSIGNOR '.lO` WESTINGHOUSE ELETBIU & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA narnronna'ron EQUALrzEn veniva Application med September 28, 1927. Serial No. 822,598.

My invention relates to refigerating systems of the compression type and particularly to devices for automatically relieving the compressor of load during periods of starting in order that the starting torque required may be lessened, and it has for an object to provide apparatus of the character designated which shall operate automatically and reliably without care or attention for an indefinite period of time. It has for a further object to provide apparatus of this character which shall be capable of effecting direct and open communication between the high and low presure portions of the refrigeratin system at times of starting in order that Vf e suction and discharge pressures of the compressor may be substantially equalized and which apparatus shall, at all other times, maintain a fluid-tight seal between the two portions in order that the eiectiveness of the compressor may not in any7 way be affected.

These and other ob'ects, which will vbe made apparent throug :out the -further de- -scription of my invention, may be attained by the employment of the apparatus hereinafter described and illustrated inthe accompanying drawing in which:

Fig. 1 'is a diagrammatic representation of a conventional compression refrigerating system having applied thereto one form of unloading device arranged in accordance withmy invention; and, v

Fig. 2 is ay partial diagrammatic representation of another form of unloading device which is similar to that shown in Fig. lwith the exception that the magnetic unloader and the motor starti winding are arranged in series instead of 1n parallel. y It is generally recognized that, at present, the 110 volt electric light circuit provided in the average household is adapted for sup- 1- l plying energy to only those electric app .ances which never require'in excess' of 15 amperes current draw. vIt rs, therefore, de-

sirable that refrigerating machines of the domestic or household type come within this requirement, but it has been found that in refrigerating machines of the enclosed type,

that iserefrigerating machinesin which both the compressor and the motor are enclosed in a single, fluid-ti ht, hermetically sealed casing and in whic lmotors of the split-phase type are generally employed, that the current draw of both starting and running windings during times of starting for -conventional motors of greater capacity than 1%; H. P. may materially exceed 15 amperes. With conventional motors of greater' than V8 H. P. the conditions are especially severe when the current supply fails only momentarily, that is, for only a few seconds, at

which time the compressor must start against full load because of the fact that the shutoff period has not been sufiiciently long to permit anyl material equalization of pressures a valved conduit between the high and low' pressure portions of the system which is closed during normal operation and which is lopen onl Such valvedy conduits have been controlled by some mechanical means, `such as a governor, which is responsive to the speed of the motor or the compressor shaft. However, apparatus of this lcharacter must necessarily bemechanically andl operatively connected to the rotating element or elements so that certain structural limitations are imposed which may seriously interfere with obtaininlg the most compact form of arrangement. -urthermore, mechanical controlllng means of the governor ty e tend to destroy the static and dynamic balance of the rotat-v ing element, which obviously is very objectionable.

`I have, therefore, conceived of actuating the equalizin valve by means of an electromagnet or so enoid, andl of utilizing the initial surge of current incidentally created in starting to temporarily energize the solenoid 'during the startingfperiods.

and holdV the valve open until such time as that it utilizes, as an actuating force, electric energy which must always be available in order for. the motor to start.4 At the same time, the'arrangement possesses far greater iop flexibility in that the valve, together with its actuating mechanism, may be located with no relation whatsoever tothe moving parts and hence certain structural limitations are avoided.

Referring to the drawing for a more detailed description of my invention, I show in Fig. 1, a compressor 10 which 1s of the reciprocating type although it is to be understood that my invention is also applicable to other forms of compression mechanisms. The compressor 10 discharges through a conduit 11 to a condenser 12, the refrigerant condensate formed therein being conveyed by means of a conduit 13 to an evaporator or cooling element 14. yAn'expansion valve 15 is interposed between the condensr 12 and the evaporator 14 and operates to control the flow of liquid refrigerant to the latter in a manner well understood in the art. Refrigerant vapor generated in the evaporator 14 is returned through a conduit 16 to the inlet of the compressor 10. The foregoing description refers merely to a diagrammaticA illustration o f the conventional form of comression refrigerating system an'd it may be said that the dischar e portion of the compressor 10 together with the conduit 11, condenser 12 and'con'duit 13 constitute the high pressure portion of the system, while the conduit 16, evaporator 14 and the intake portion of the compressor 10 constitute the low pressure portion of the system. A check valve 17 is preferably'provided in the conduit 16 for resisting back leakage or return-flow of the high pressure refrigerant fluid to the low pressure portion of the system at any time.

The compressor 10 is driven by an electric motor which may be of the split-phase type embodying start-ing and running

windings

21 and 22 respectively. One side of both windings is connected by a common lead 23 to one leg of a power main represented at 24, While.

the other sides of both windings are connected through respect-ive leads 25 and 26 to the other leg of the power`main 24. Located in the lead 23 is a master controlling switch 27 which is actuated automatically in response to the conditions prevailing within the refri erating system. In other Words, this switc operates automatically to startand 4pressure an stop the refrigerating system in order to maintain predetermined temperatures 1n the refrigerator box, all as is well understood in the art.

Connected in series with the starting winding 21 and the lead 25 is the starting winding switch 28. While various forms of switches may be employed, I have shown, for purposes of illustration, a switch composed of transparent glass casing 29 preferably formed in the manner illustrated and containing bodies of conducting liquid, such as mercury, 31 and 32, having normal levels such as indicated at 33, 34 and 35.

Terminal connections

36 and 37 are provided in the casing 29 and are connected in the lead 25 as shown. Associated with one leg of the casing 29 'is a solenoid windin or coil 38 which is connected in circuit with the lead 26 of the running winding circuit, as shown. A member 39 of suitable magnetic material is provided in the casing 29 and serves as an armature member for the coil 38.

Connected in parallel with the starting winding 21 through leads 41 is a solenoid 42 which, like the starting winding, is controlled by the switch 28. The solenoid 42 is composed essentially of a coil 43v and an armature member 44. The armature member 44 is connected through operating mechanism such as a lever 45, to a valve 46, a spring 47 being provided for normally retaining the valve in closed position, such as illustrated. The valve 46 is provided with

connectionsl

47 and 48, one of which is connected by a conduit 49 to the high pressure portion of the refrigerating .system and the other connection bymeans of a conduit 51 to the low pressure portion of the system, the

conduits

49 and 51 and the valve 46 forming, in effect, ahy-pass aboutthe compressor and a direct connection between the .condenser 12, and is prevented from escaping .mto the remainder or low pressure portion of the system by the check valve 17. It is obvious, that bg' preventing the escape of high into the low pressure and lowtemperature portion of the system during the various inactive periods, serious thermo-dynamic losses are avoided. 4 y

However, upon the temperature in the rehigh temperature refrigerant f frigerator rising suiiciently, the switch 27 automatically closes to energize the running winding 22 of the motor. At such times, there .is an initial surge of current (assuming, for

example, 1/8 H. P. motor and current of 110 volts, 60 cycles) of approximately 8 amperes, this current being capable of energizing the solenoid winding 38 of the starting winding switch 28 suiciently 'to draw the armature core downwardly and cause the conducting Huid in the casing 29 to assume the level indicated at 52 and thus complete the circuit between the terminals'36 and 37. In other words, at such times, the starting winding 21 is connected through the lead 25 to the power main 24.

The closing of the switch 28 also connects the solenoid 42 in circuit with the power main, drawing the armature core 44 downwardly and thus openingthe valve 46. Opening of the valve 46 provides direct communication between the high and low pressure portions of the system and hence the pressures are substantially equalized therebetween and the compressor 10 is incapable of building up any pressure difference as long as the valve 46 is open.

Upon the motor reaching its normal operating speed, the current draw drops to normal, for example, from 8 amperes to 21/2 amperes and, the latter amount of current being insuiicient to energize the coil 38 suiciently to retain the core 39 in its down position, the latter rises to the position illustrated and the conducting iluid within thecasing 29 separates into two bodies, breaking the circuit of the starting winding 21 and of the solenoid 42. At this time the spring 47 acts to draw the solenoid core 44 upwardly and to close the valve 46. Thereafter, the compressor is free to develop a pressure diierence between the high and low pressure portions of the refrigerating system in a manner well understood in the art. The starting winding switch 28, the solenoid 42 and the valve 46 remain in t-he same positions until such time as the master control switch 27 has opened tok stopA the operation and until it again closes to restart the operation, Whereupon the starting winding 2l is temporarily energized and the valve 46 is again temporarily opened inthe manner heretofore described. y

Although it will be appa-rent from the foregoing description of operation thatlrather severe conditions are imposed upon the compressorand motor in normal starting, nevertheless, the conditions prevailing are even more severe when the' current in the power main fails temporarily.

As'stated heretofore, the machine normally operates intermittently, that is, aV period of operation of one or more hours is usually -followed by an inactive period of one or l' more hours. The machine, therefore, re-

mains inactive for a substantial period and even though the check valve 17 is provided, K there is some reduction in the pressure difference prevailing between the high and low pressure portions of the system. This is caused by the fact that leakage of some refrigerant fluid through both the compressor' and the check valve is unavoidable. However, when the machine is operating andv the current in the main fails for a period of, for example, ten seconds or less, the inactive period is so short that, at time of starting, that is, when the current supply returns tothe main 24, the pressure dii'erence is almost exactly that prevailingduring normal operation. In other Words, the inactive period has been of insuiiicient duration to efect any noticeable reduct'on in pressure diierence between the high and low portions. At times, such as these,'my pressure equalizing device is especially valuable for preventing excessive current draw and for insuring proper starting of the refrigerating machine.

teferring now to F ig. 2, I show a form of control system which is similar to that shown in Fig. 1, with the exception that the electromagnetic means for actuating the pressureequaliz'ng valve is arranged in Aseries with the motor starting winding instead of in parallel. In this arrangement, the motor starting winding 21 is connected through a lead 61 to the coil 43 of the solenoid 42 and 'through a lead 62 to the terminal connection 36 of the switch 28. The other terminal connection 37 of the switch 28is then connected through a lead 63 to a leg of the power. main 24, as illustrated. v

It will be apparent from the oregoing description that the motor starting winding 21, the solenoid 42 and the switch 28 are all arrangedin series so that the latter controls the iow of current through the circuit thus formed. Operating results are thus procured similar to those obtained with the system illustratedin Fig. 1.

It will be apparent from the foregoing description, that, by means of the foregoing arrangement, overloading of the motor and the passage of abnormal current tlow is positively prevented, the load on the motor belng almost entirely removed until such time as it attains its normal operating speed. Itwill b e further apparent that, by means of my invention, both the reliability of operation as well as the commercial application of refrigerating machines of the household type are very materially improved. 5

While I have shown `my invention in but one form, it will be obvfous to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spiritthereof, and I desire, therefore, that only such limitationsv shall be placed thereupon as are imposed by the prior art, or as are specifically set forth in the appended claims.

What I claim is l. In combination with a refrigerator system embodying a low-pressure portion including an evaporator, a high-pressure portion including a condenser, a compressor for circulating refrigerant fluid from the lowpressure portion to the high-pressure portion, a motor for driving the compressor, and means for supplying electrical energy to the motor, of means for equalizing the pressure difference between the high and low pressure portions of the system, and means responsive to the initial surge of current through the motor for rendering said equalizing means effective.

2. In combination with a refrigerator system embodying a low-pressure portion in-` cluding an evaporator, a high-pressure portion including -a condenser, a compressor for circulating refrigerant fluid from the lowpressure portion to the high-pressure portion, a motor for driving the compressor, and

means for supplying electrical energy to the motor, of communicating means directly connecting the high and -low-pressure portions of the refrigerating system, means for opening and closing said connecting means, and means responsive to the initial electrical energy surge through the system for actuating said opening and closing means to open position.

3. In combination with av refrigerator system embodying a low-pressure portion including an evaporator, a high-pressure portion including al condenser, a compressor for circulating refrigerant fluid from the lowpressure portion to the high-pressure portion, a motor for driving the compressor, and means for supplying electrical energy to the motor, of a means for by-passing the compressor and providing direct communication between the high and low-pressure portions of the system` said means including a valve, electro-magnetic means yfor actuating the valve to open position, and means res onsive to the initial electrical ener surge t rough the system for energizing said electro-magnetic means. l

4. In combination with a refrigerating system embodying a low-pressure portion including an evaporator, a high-pressure portion including a condenser, a compressor for circulating refrigerant fluid from the low-pressure portion to the high-pressure portion, a motor for driving the compressor, and means for connecting the motor in circuit with a source of electrical energy, of a master switch for controlling the ow of electrical energy to the motor, a normally closed valved passage for by-passing the compressor and for directly connecting the high and low-pressure portions of the system, and electro-magnetic means effective upon the abnormal flow of current incident to starting of the motor for opening said valve.

5. In combination with a refrigerating system embodying a low-pressure portion including an evaporator, a high-pressure portion including'a condenser, a compressor for circulating refrigerant fluid from the lowpressure portion to the high pressure portion, a motor for driving the compressor, and means for connecting the motor in circuit with a source of electrical energy, of a passage by-passing the compressor .and connecting the high and low-pressure portions of the system, a master switch for controlling the flow of electrical energy from the source to the system, and electro-magnetic means rendered effective by the initial surge of current through the motor for temporarily opening said valve. y

6. In combination with a refrigerating system embodying a low-pressure portion including an evaporator, a high-pressure portion including a condenser, a compressor for circulating refrigerant fluid from the low-pressure portion to the high pressure portion, a motor for driving the compressor, said motor embodying starting and running windings, and means for connecting the motor to a source of electrical energy, of a master switch for controlling the flow of electrical energy from the source to the system, a switch for controlling the fiow of electrical energy through the starting winding, means normally ineffective for equalizing the pressure between the high and low-pressure portions of the system, means for actuating said pressure-equalizing means, and means responsive to abnormal flow of current incident to starting of-the motor for temporarily closing the starting windin switch and for temporarily rendering sai pressure-equalizing means effective.

7. In combination with a refrigerating system embodying a low-pressure portiony including an evaporator, a high-pressureportionincluding a condenser, a compressor for circulating refrigerant fluid from the low-pressure portion to the high-pressure portion, a motor embodying running andr starting windings yfor driving the compressor, and means for connecting the motor in circuit with a source of electrical energy, of a master switch for controlling the flow of electrical energy from the source to the system, a switch for controlling the flow of electrical energy through the starting winding, pressure-equalizing means normally ineffective connecting the high and low-pressure portions of the system, and electro-magnetic means for actuating both the starting winding switch and for rendering the pressure equalizing means effective upon temporary abnormal flow of current created by the starting of the motor.

8. In combination with a rerigerating system embodying a low-pressure portion inf through the start-ing winding circuit, electromagnetic means for actuating lthe starting winding switch, pressure equalizing means normally ineii'ective for connecting the high and low-pressure portions of the system, and electro-magnetic means for actuating said pressure-equalizing means to render the same eliective, both said lirst and second electromagnetic means being adapted to be energized by the abnormal flow of current to the system created during` the motor starting periods.

9. In combination with a refrigerating system embodying a low-pressure portion including an evaporator, a high-pressure portion including a condenser, a compressor for circulating regrigerant fluid from the lowpressure portion to the high-pressure portion, a motor embodying running and starting windings for driving the compressor, and means for connecting the motor in circuit with a source of electrical energy, of a master switch for controlling the lowof electrical energy from the source to the system, a switch for controlling the flow of electric energy through the starting winding, electro-magnetic means connected in circuit with the running winding for actuating the starting winding switch, means normally .ineffective for equalizing the pressures between the high and low-pressure portions of the system, and electro-magnetic means connected in circuit with the starting winding for rendering said pressure equalizing means effective, both said first and second electro-magnetic means being adapted to be energized by the abnormal flow of electrical energy created during starting periods of the motor.

10. In combination with a rerigerating system embodying a low-pressure portion including an evaporator, high-pressure portion including a condenser, a compressor for circulatlng refrigerant flmd from the low- -pressufre portion to the high-pressure portion, amotor embodying running and starting windings for driving the compressor, and means for connecting the motor in circuit with a source of electrical energy, of a switch'for controlling the How of electrical energy through the motor starting winding, electro-magnetic means connected in circuit with the motor running winding for actuating said switch, pressure-equalizing means normally ineffective for connecting the high and low-pressure portions of the system, electro-magnetic means for actuating said ypressure-equalizing mea-ns to render the same temporarily eective, and means responsive to the initial electrical energy surge through the motor for actuating said pressure equalizing means.

11. In combination with a refrigerating system embodying a low-pressure portion including an evaporator, a high-pressure portion including a condenser, a compressor forv circulating refrigerant liluid from the lowpressure portion to the vhigh-pressure portion, a motor embodying running and starting windings for driving the compressor, and means for connecting the motor in circuit with a source of electrical energy, of aswitch for controlling the. flow of electrical energy Vthrough the motor starting winding,`electromagnetic means responsive to theA ini/tial surge of current through the motor runningwinding for actuating said switch, pressureequalizing means normally ineffective for connecting the high vand low-pressure portions of the system, and electro-magnetic means connected in parallel with the motor starting winding whereby electro-Ina etic means for actuating said pressure-equa 'zing device is controlled by the motor starting Winding switch;

12. In combination with a refrigerator system embodying a low-pressure portion including an evaporator, a high-pressure portion including a condenser, a compressor for circulating refrigerant fluid from the lowpressure portion to the high-pressure portion, a motor for driving the compressor, and means for supplying electrical energy to the motor, of means4 for by-passing the compressor and connecting the low-pressure and igh-pressure portions of the system, said means including a normally closed valve, and means responsive to the abnormal surge of motor-starting current for opening said valve. v a' 13; In combination with a refrigerator system embodying a low-pressure portion including an evaporator, a high-pressure por- A tion including a condenser, a compressor for circulating refrigerant fluid from the lowpressure portion to the high-pressure portion, a motor for driving the compressor, and means for supplying electrical energy to the motor, of means "connecting the compressorv cylinder directly'tothe low-pressure portion of the system, said means including a normally closed valve, and electromagnetic means responsive to the abnormal surge of motor-starting current for opening said valve.

14. In combination with a refrigerator system embodying a low-pressure portion including an evaporator, a high-preul'e portion including a condenser, a compressor for circulating `refrigerant uid from the llow- Ypressure portion to the high-pressure portion, a motor for drivingthe compressor, and means for supplying electrical energy vto the motor, of a pressure-equalizin passage connecting the compressor cylin er directly to the 10W-pressure portion of the system, a valve normally closing said passage, and electromagnetic means responslve to the abnormal surge ofmotor-starting current for openin said valve.

n testimony whereof I have hereunto subscribed my name this 12th day of Sept., 1927.

. MATSON C. TERRY.