US3000186A

US3000186A - Control means for refrigerating apparatus

Info

Publication number: US3000186A
Application number: US802524A
Authority: US
Inventors: Leonard J Mann
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1959-03-27
Filing date: 1959-03-27
Publication date: 1961-09-19
Anticipated expiration: 1978-09-19

Description

sept. 19, 1961 21M/1N 3,000,186

CONTROL MEANS FOR REFRIGERATING APPARATUS Filed March 27, 1959 2 SI'Leecs--SheetI 1 INVENTOA Leonard J. Mann His Attorney Sept. 19, 1961 J. MANN 3,000,186

CONTROL. MEANS FOR REFRIGERATING APPARATUS Filed March 27, 1959 2 Sheets-Sheet 2 IN1/NTM Leonard J, Mann Byw-wgw His Attorney United States Patent O 3,000,186 CONTRGL MEANS FOR REFRIGERATING APPARATUS Leonard J. Mann, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Mar. 27, 1959, Ser. No. 802,524 8 Claims. (Cl. 62-153) rllhis invention relates to refrigerating apparatus and more particularly to frostless refrigerators.

This invention is a continuation-impart of my copending applications Serial No. 617,170 filed October 19, 1956, now Patent No. 2,907,180, and Serial No. 633,109 led January 8, 1957, now Patent No. 2,912,834, to which further reference may be made for additional details.

In frostless refrigerators, such as are disclosed `in said applications, the evaporator is isolated from the compartments which are cooled by the 'circulation of air from the evaporator. This prevents frosting in both the above and below freezing compartments but the frost does collect on the evaporators. It has been found that occasionally frost will collect in the below freezing compart ment when its door is left open for a considerable period of time and ythe air circulation is stopped.

It is an object of this invention to prevent the formation of frost in a frostless refrigerator when the door is opened.

It is another object of this invention to insure circulation of air through the below freezing compartment whenever its door is opened.

These and other objects are attained in the two forms shown inthe drawings in which the freezing evaporator is located beneath the below freezing compartment while the above freezing compartment is either cooled by air circulation from this evaporator or another evaporator connected in series with it. To prevent any formation of frost in the below freezing compartment when the door is left open for considerable periods, I provide a double throw switch actuated by the opening and closing of the door which will insure operation of the fan for circulating the below freezing compartment air through the evaporator beneath and then returning the air to the compartment whenever this door is open.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE 1 is a vertical sectional view through a single evaporator form of frostless refrigerator embodying my invention;

FIGURE 2 is a vertical sectional view through a two evaporator frostless refrigerator embodying my invention;

FIGURE 3 is a wiring diagram for the single evaporator refrigerator shown in FIGURE 1; and

FIGURE 4 is a wiring diagram for the two evaporator refrigerator shown in FIGURE 2.

Referring now more particularly to FIGURE l, there is shown an insulated refrigerator cabinet 20 containing an above freezing compartment 22 located above the below freezing compartment 24, with the compartments separated by an insulated wall 26. 'Ihe compartments respectively are provided with insulated

doors

28 and 30. Beneath .the false metal bottom wall 32 of the freezing compartment 24 is a cross iin and tube evaporator 34 having vertical fins extending from front to back.

'This evaporator 34 is maintained at temperatures below ice freezing, such as 10 F., by the motor-compressor unit 36 which withdraws evaporated refrigerant through the suction conduit 38 and forces the compressed refrigerant into the condenser 40 from which the liquid refrigerant is supplied through a flow restricting capillary tube 42 back into the evaporator 34.

At the rear of the freezing compartment 24 is a centrifugal fan 44 driven by an electric motor 46 for withdrawing air from the rear of the evaporator 34 through the duct 48 and discharging the air through two

dischargel ducts

50 and 52. The discharge duct 50 extends up` wardly behind the rear wall of the compartment 22 and discharges into this compartment through an upper opening 54. Air is withdrawn from the compartment 22 through lower side wall openings 56 connecting with the duct S8 surrounding the front of the compartment 24 which discharges into the plenum chamber 60 at the front of the evaporator 34. Air is discharged from the duct 52 through openings 62 at the upper rear of the compartment 24 which provides even distribution of air ow through the compartment 24. 'This air isV then drawnv through openings 64 into the duct 58.

As shown in FIGURE 3 between the supply conductor L1 and the supply conductor L2, there is connected a thermostat 66 including a thermostat bulb 68 mounted at the rear of the evaporator 32 and connected by capillary tube to a bellows actuator 70 operably connected to the switch 72. This switch 72 connects the supply conductor L1 and the conductor 74 with the conductor 76 and the motor-compressor unit 36. The motor-compres-V sor unit 36 is connected by the conductor 78 to one termi-V nal of the double throw defroster switch 82 normallyV held in engagement with the contact 82 by the defrost control 84. The double throw switch 82 is connected by'- the conductor 86 to the line L2 to complete the energiz'V ing circuit of the motor-compressor unit 36.

Since frost gradually accumulates upon the evaporator because of its low temperature, the defrost control 84 periodically moves the double throw switch 82 into engagement with the contact 88 to deenergize the motorcompressor unit 36 yand to complete the energization of the defrost heater 90 located in heat transfer relation with the evaporator 34. The defrost control as well as the heater 90 is connected to the conductor L1 by thel conductor 92. The defrost control 84 is permanently connected to the supply conductor L2. By the operation of the defrost control 84, vthe heater 90 is periodically connected through the contact 88 to switch 82 and the conductor 86 with the supply conductor L2 to heat the evaporator 34 while the motor-compressor unit 36 is idle for defrosting.

The fan motor 46 is normally connected by the double throw door switch 94 through th conductors 96 and 98 in series with the thermostat 66 so that the motor-corn# pressor unit 36 and the fan 46 cycle simultaneously. A switch 121, normally closed, connects the motor 46 to the contact 80 so that it is likewise deenergized and stopped during the defrosting period. The switch 121 is operated to open position by the opening of the door 28. This stops the motor 46 and the fan 44 during the time the door 28 is open. The double thro-w switch 94 is normally held in closed position against the force of they spring 123 by the door 30 when it is in the closed posi! tion through the use of a plunger 125. IIn this position, the fan motor 46 is connected in series with the contact" 72. The

doors

28 and 30 are opened independently of each other, and normally only one of these doors will be opened at a time.

Under normal conditions of operation, no frost will collect in either of the

compartments

24 or 22. However, should the door 30 be left open for considerable periods of time, there is a possibility under conditions of highhumidity that frost may ycollect upon the ice tray 127 andthe bottom 32 of the compartment 24. To prevent this, the double throw switch 94 is operably connected by the plunger 125 to the door 30 to release the switch 94 so. that. it will move to its vdottediline position connecting( with the contact 129` and the conductor 131 with the supply conductr L1 so as to shunt the thermostat 66 and its switch 72 and cause continuous operation of the fan motor 46 as long asY the door 30 is open. The reclosing of the door 30 will move the switch 94 back to its full line position to again make the 'operation of the fan motor 46 dependent upon the closing of theswitch 72. The operation Vof the fan while the door 30 is open will prevent accumulation of frost within thccompartment 24. If the door 28 is frequently opened at the same time the door 30 is open, the'door switch 121 may be shunted by the manual switch 133 andthe conductors' 135 fand 137 to insure the operation of the fan motor 46. Y

IIn FIGURE 2, the below freezing compartment 224 is similarly cooled by the evaporator 234' beneath the false bottom 232. Air is similarly drawn from the compartment 24 through the openings*2,64 into the duct 258 which conducts the `air into the plenum chamber 260 at the front of the evaporator. The air is drawn through the evaporator 234 from front to rear by the fan 244 driven by the electric motor 246. This air is discharged through the duct 252 at the rear and issuesV through the apertures 262 in the rear. The evaporator 234 is defrosted by the electric,` heater 290, and the defrost water is collected from a drain pan 301, passing through a liquid trap 302 from which it ows into the drain pan 303.

.bove the compartment 224 is the above freezing con-rpartment 222 having its own evaporator 304 behind a false rear wall 300. VAiris drawn from the bottom of the compartment 222-.by thel fan 305 driven by an electricv motor 306 and circulated through the passage 307 around the evaporator 304 and discharged through openings 308 atl the top back into the compartment 222. The fan motr306 is controlled by a thermostat 309 adjacent the outlet 308 to control the temperature of the compartment 222 independently of the compartment 224. The compartments 222 and 224y are provided with

separate doors

228 and 230. The evaporator 304 is connected in series with the evaporator 234; both are controlled by a thermostat 268 set to provide a defrosting cycle of the plate 304 and to keep the evaporator 234 below freezing temperatures at times. Y The defrost Water from the evaporator 234 is conducted by the conduit'310 into the drain pan 303.

Similarly to FIGUREA 1, no frost will'normally collect eitherY compartment. However, should the door 230 be left open'for prolonged periods, there is a danger that ost Will accumulate on the false bottom 232Y and possibly the inlet duct 248. To prevent this, thedouble throw switch'294 is provided Which normally connects ythrough the conductor 296 to themcontact 272 of the thermostatic vswitch 266 actuated by the bellows 270 in accordance with the temperature of the "thermostat bulb 268.v '.The'th'ermostat 266 is merely diagrammatically shown and is provided with a snap action mechanism not shown and suitable vvadjustment to cause it to yclose at a temperatur'e'of about 35 F. and to open at a temperature of about 41.05V E. This setting Will insure the defrosting of the evaporator 304 during each olf cyclewhile the evaporator 234 is maintained at below freezing temperatures at all times.

v"These evaporators 234and 304 are connected in Vseries with each other and withiaI refrigerant liquefying means` which includes asealed motor-compressor unit 236 connected through the

conductors

274 and 276 as well as the switch 272 with the supply conductor S1. VTheiopposite terminal'of the motor-compressor nnit 236 is connected by the conductor 278 with Vthe upperV contact '280 of the double throw defroster' switch 282 controlled by the defrost control 284. The switch 282 either connects the motor-compressor unit S2736 and the fan motor 246 through lthe conductor 286 withthe supply conductor S2`orit dissannscts the naief-@nasser unit '.236 slid the, fen

motor 246 by moving into engagement with the contact 288 to connect with the defrost heater 29,0 to defrost the evaporator 234. The defrost control 284 and the heater 290 are connected bythe conductor 292 with the supply conductor S1. The fan motor 246 may be stopped through the opening of the door switch 321 by the opening of the'above freezing compartmentdoor 228. However, this switch may be Vshunted by the switch 333.

The fan 2,46jis madeY to operate upon the openingv of the door 230'by the plunger 325 and the spring 323'whieh moves it into engagement with the contact 329 to connect through the conductor 331 with the supply conductor S1. This will insure the operation of the fan motor 246 whenever the door 230 is opened. Through this arrangement,

frost is prevented from forming in the below freezingV compartment Yshould the door be left open for considerable periods 'of time. v

'While theembodimentsv of the present invention ask herein disclosed,-constitute preferred forms, it is to be', understood that other forms might be adopted.

What is claimed is as follows:

l. A refrigerator including an insulated cabinet having above freezing and below freezing compartments separated from each other, refrigerant liquefying and evaporating means located outside'said compartments, fan meansv for circulating air from said compartments into heat trans fer with said evaporating means and return, thermostatic switch means for energizing and deenergizing said liquefying meansV and said fan means, a door for said below freezing compartment, andra double throw switch operated by` the closing of the door to a position connecting said fan means in serieswith said thermostatic switch meansl andl operated by the opening of the door to a position connesting the fan means in' shunt with Vthe thermostatic switch means. Y

2. A refrigerator including an insulated cabinet having above freezing and below freezing compartments separated from each other, refrigerant liquefying and evaporating means located outside said compartments, fan means for circulating air from said compartments into heat transfer with said evaporating means and return, thermostatic means for controlling said liquefying means, and said fan means, a door for said below freezing compartment, a first supply conductor connected to said thermostatic means, a second supply conductor, an electric defrostV heater in heat transfer relation to said evaporatingLA means having one terminal connected to said first supply conductor, a defrost control alternately connecting in one alternate position said liquefying and fan means -to said second supply conductor and in the other alternate position connecting said'heater to'said second supply .conductor, a door for said below freezingeompartment, a double throw switch operated by the closing of the door for connecting the fan means in series with-said thermostatic means and operated by the opening of the door for connecting'said fan means directly to said lrst supply conductor, said defrost control having means preventing energization of said fan means during the energization-'ofi saidheater. l

3. A refrigerator including an insulated cabinet containing a below freezing compartment and an above freezing compartment, a'rst'evaporator and a second evapo- 'rator outside saidY compartments, Vrefrigerant liquefying d ing of said door to shunt said thermostatic switch means to operate said rst fan means.

4. A refrigerator including an insulated cabinet containing a below freezing compartment and an above freezing compartment, a first evaporator and a second evaporator outside said compartments, refrigerant liquefying means operatively connected in series circuit with said evaporator, a first fan means for circulating air from said below freezing compartment into heat transfer with said rst evaporator and return, a second fan means for circulating air from said above freezing compartment into neat transfer with said second evaporator and return, thermostatic switch means for cycling said liquefying means and said first fan means, a door for said below freezing compartment, a double throw switch operated by the closing of said door to connect said first fan means in series with said thermostatic switch means and operated by the opening of said door to shunt said thermostatic switch means to operate said first fan means, and a second thermostatic means responsive to the temperature of said above freezing compartment for controlling said second fan means independently of said door and said thermostatic switch means.

5. A refrigerator including an insulated cabinet having a below freezing compartment, refrigerant liquefying and evaporating means located outside said compartment, fan means for circulating air from said compartment into heat transfer with said evaporating means and return, thermostatic means for controlling said liquefying means and said fan means, a door for said below freezing compartment, and control means mechanically connected to and mechanically operated by said door and directly and immediately responsive to each opening of said door for insuring operation of said fan means whenever said door is opened.

6. A refrigerator including an insulated cabinet having a below freezing compartment, refrigerant liquefying and evaporating means located outside said compartment, fan

means for circulating air from said compartment into heat transfer with said evaporating means and return, thermo- Static switch means for energizing and deenergizing said liquefying means and said fan means, a door for said below freezing compartment and a double throw switch arrangement operated by the closing of the door lto a position connecting said fan means in series with said thermostatic switch means and operated by the opening of the door to a position connecting the fan means in shunt with the thermostatic switch means.

7. A refrigerator including an insulated cabinet having a compartment to be cooled, refrigerant liquefying and evaporating means located outside said compartment, fan means for circulating air from said compartment into heat transfer with said evaporating means and return, thermostatic means for controlling said fan means, a door for said compartment, and control means mechanically associated with and mechanically operated by said door and directly and immediately responsive to each opening of said door for insuring operation of said fan means whenever the door is opened.

8. A refrigerator including an insulated cabinet having a compartment to be cooled, refrigerant liquefying and evaporating means located outside said compartment, fan means for circulating air from said compartment into heat transfer rwith said evaporating means and return, thermostatic switch means for energizing and deenergizing said liquefying means and said fan means, a door for said compartment, and a double throw switch arrangement operated by the closing of the door to a position connecting said fan means in series with said thermostatic switch means and operated by the opening of the door to a position connecting the fan means in shunt with the thermostatic switch means.

References Cited in the file of this patent UNITED STATES PATENTS 2,801,525 Bixler Aug. 6, 1957