US2187061A - Refrigerating apparatus - Google Patents

Description

Jan: 16, 1940. NJ, MI H 2,187,061

REFRIGERATING APPARATUS Filed Jan. 51, 1935 Zrz, INVENTOR BY 2 z 5 ATTORNEYS Patented Jan. 16, 1940 UNITED STATES PATENT OFFICE REFRIGERATING APPARATUS poration of Delaware Application January 31, 1935, Serial No. 4,336

7 Claims.

This invention relates to refrigerating apparatus and more particularly to air conditioning. Air conditioning has increased in popularity within recent years. However, in most cases the air temperature within the'building, room, or enclosure has been maintained constant by an ordinary thermostat control while the temperature without fluctuated. It has been found that under these conditions on an extremely warm day there is a considerable shock tothe person wher leaving an air conditioned building, room or enclosure because the difference in temperature is sometimes of the order of 20 or more. For example, in many cases the thermostat is set so as to maintain a room temperature of about 75 F. When the temperature without rises to 95 or 100 F. there is experienced a sudden temperature change of 20 to 25 F. when leaving the air conditioned room or build- 20 ing. This frequently causes some people to feel sick. The ideal condition is to have a minimum temperature of 72 F. in the room and as the outside temperature of the air rises above 70 to have a progressively greater temperature 25 difference between the outside air and the air within the air conditioned room or building. For example, when the outside temperature is 80 F. it is desirable to have a room temperature of about 75 F. While when the outdoor tempera- 30 ture is 95 F. it is desirable to have an indoor temperature of about 80 F.

It is an object of my invention to provide an air conditioning system which will maintain the proper temperature conditions within a room ac- 35 cording to the outside temperature so that no sickness or shock will result from passing into or out of the air conditioned room or building.

It is a further object of my invention to provide an improved control means for an air con- 40 ditioning system responsive to both indoor and outdoor temperatures to maintain the proper temperature diiferential between the indoor and outdoor temperatures.

Further objects and advantages of the prescnt invention will be apparent from the followtemperatures between the outdoor air and the air within the room.

Referring now more particularly to the drawing, there is shown a building provided with a room 22 to be conditioned and provided with 5 a basement room 24 where there is located a refrigerant liquefying apparatus generally designated by the reference character 26. The refrigerant liquefying apparatus 26 comprises a compressor 28 for compressing the refrigerant 10 and for forwarding the compressed refrigerant to a condenser 30 where the compressed refrigerant is liquefiedand collected in a receiver 32. From the receiver the liquid refrigerant is forwarded through a supply conduit 34 to an air conditioning unit 36 located within the room 22 to be conditioned.

This air conditioning unit 26 contains an expansion valve 38 which controls the flow of liquid refrigerant from the liquid line 34 to an evaporat- 20 ing means 40 also located within the air conditioner 36. The operation of the valve 38 is controlled by a thermostat 42 located near the outlet of the evaporator 40 in order to permit a proper supply of liquid refrigerant to be fed into the refrigerant evaporator 40. A motor driven .fan 44 is provided in the upper portion of the air conditioner for drawing in air from the room through the opening 46 in the lower portion of the cabinet over the surfaces of the evaporator 40 and discharging the air out through the opening 48 in the top of the air conditioner.

A pan 50 is provided in the bottom of the air conditioner beneath the evaporator 40 for collecting any moisture condensed from the air upon the surfaces of the evaporator.

The evaporator evaporates the liquid refrigerant and absorbs heat from the air which is circulated through the air conditioner by the motor driven fan 44. The evaporated refrigerant 0 is returned to the compressor through the return conduit 52. The compressor 28 is driven by an electric motor 54 which is connected by electrical conductors 56 to a source of electric energy designated by the reference character 58. The motor driven fan 44 is also connected to the source of electric energy by the electrical conductors 60 under the control of a switch 62. Heretofore, the operation of such a refrigerating system has been controlled by a thermostat responsive to the temperature of the room 22. However, such a control does not take into account changes in outside temperature which, of course, fluctuate rapidly throughout an ordinary summer day. As before stated, under such conditions the temperature difierence between the outside air and the air in the room may become too great when the outside temperature rises rapidly to a rather high temperature such as 98 or 100 F. or more.

It has been determined that the most desirable temperature regulation would be one which would control the temperature of the room in accordance with changes in outside temperature with a minimum temperature in the room of about 72 F. For example, when the outside temperature is F. the room temperature should be 72 F. When the outside temperature is 80 F. the inside temperature should be about 75 F. When the outside temperature is about 95 F. then the room temperature should be about F. However, this sort of temperature regulation cannot be accomplished by ordinary automatic control which heretofore have been used for air conditioning.

In order to provide an automatic control which is capable of maintaining such a variable differential between the outdoor temperature and the room temperature, I have provided a peculiar form of pressure responsive switch generally designated by the reference character III which is connected in the electric circuit 56 in series with the compressor driving motor 54. This switch is provided with two bellows, each having an effective area of about one square inch, one designated by the reference character 12 and the other designated by the reference character I4.

These bellows have their upper ends fastened to and fixed to a flange 16 forming the upper portion of the switch I0. This fixed upper end of the bellows 12 is connected by a tube 18 to a thermostat bulb 80 located in contact with the air in the room. The bellows 14 is connected by a tube 82 to a thermostat bulb 84 located outside the building in contact with the outdoor air. The two bellows are connected to the opposite arms 86 and 88 of a T-shaped double bell crank lever which is pivoted upon the pin 90 to the base 92 of the switch 10. The other arm 94 of the bell crank lever has a forked or slotted lower end which receives a pin 96 protruding from a sealed mercury tube switch support 98 which is pivoted upon the Pin I02 also extending from the base 92. upper portion of this pivotal support 98 holds a sealed glass or silica tube l04 containing mercury and a pair of switch contacts at its right end. These switch contacts are connected into the electric circuit 56.

When the pivotal support 98 moves in a' clockwise direction about its pivot pin I02 from the position shown in the figure, the mercury within the tube flows to the right end of the tube and completes the circuit across the contacts. When the mercury tube is in the position shown in the figure or to the left of the position shown in the figure, the mercuryis not in contact with the contacts and the electric circuit 56 remains open.

In the preferred embodiment I fill the thermostat 80 and the bellows 12 with ammonia and I fill the thermostat 84 and the bellows 14 with butane. When the outdoor temperature is 70 F. the butane exerts a pressure of 17 lbs. When the temperature within the room is 72 F. the ammonia exerts a pressure of about 119 lbs. such conditions when the outdoor temperature is 70 and the indoor temperature is 72, it is not necessary to change the temperature of the air within the room since this is the desired temperature. Therefore, it is necessary to interpose a spring or-some other means of suiflcient force to The Under counteract the excess force of the ammonia bellows 12. In order to do this I provide a spring retainer I06 connected to the lower end of the ammonia bellows 12 which holds the upper end of a coil spring I08. The lower end of this coil spring is held by .a. low spring retainer 0 which is held by a screw H2 which is used for adjusting the tension of this spring I08. This spring is preferably adjusted to provide a force of about 102 lbs. and under such conditions causes the switch to assume the position shown in the drawing.

Should the indoor temperature rise, without a change in the outdoor temperature, the ammonia bellows 12 will expand causing the bell crank lever to turn in a counter-clockwise direction about its pivot pin'90 to thereby cause the mercury tube to refrigeration to the room. However, should the outside temperature rise to 80 and the indoor temperature rise to 75 the switch will still remain substantially in the position shown in the drawing since then the vapor pressure of the butane would rise to 23 pounds while the ammonia pressure would rise approximately the same amount to 126 lbs. Thus the pressure of the butane plus the spring pressure would equal the ammonia pressure. Similarly when the outdoor temperature is F. and the indoor temperature is 80 F. the vapor pressure of the butane will rise to about 33 lbs. while the vapor pressure of the ammonia, will rise about the same amount to 138 lbs. This will cause the switch to remain substantially in the position shown. Thus when the proper temperature differential between the outdoor air and the room is maintained the switch remains in the off position. However, when this temperature differential becomes less than this desired temperature differential the air conditioning unit supplies refrigeration to the room.

While I have disclosed ammonia and butane as the controlling mediums in my preferred embodiment, others may be selected to provide substantially the same or even difierent temperature conditions if desired.

In selecting the volatile fluids or refrigerants for the two bellows and their thermostats, it is necessary in order to maintain the desired conditions heretofore described that the increase in pressure of the volatile fluid in the thermostat and bellows responsive to the outside temperature between the temperature of 70 F. and 95 F. be approximately equal to the increase in pressure of thevolatile fluid within the bellows and thermostat bulb responsive to the inside temperatures between the temperatures of 72 F. and 80 F. Instead of ammonia and butane as fluids for the bellows and their thermostats, methyl chloride may be used for the inside thermostat and its bellows while ethyl chloride may be used for the outside bellows and its thermostat since their increases in pressure under the ideal conditions are about equal. Likewise, mixtures of volatile fluids may be used to obtain the same results such as a mixture of propane and methyl chloride in the inside thermostat and its bellows and of a mixture of ethyl chloride and butane in the outside thermostat' and its bellows. This result maylikewise be accomplished by employing additional thermostat control devices, by providing 'a variable spring tension or resistance, by changing the leverage between the bellows, and by changing the size and effective area of the bellows.

In order to obtain different conditions other volatile mediums may be used in the thermostat ing the temperature of said medium, and op-' posed means rigidly connected together in direct opposition to each other, one responsive to the temperature of the medium and the other responsive to the temperature outside of said enclosure for regulating said means for changing the temperature of the medium, one of said temperature responsive means having a fluid with a high vapor pressure and the other having a fluid with a lower vapor pressure, and spring means opposing the temperature responsive means having the higher vapor pressure fluid.

2. A temperature regulating system for providing a temperature differential between a first medium having a fluctuating temperature and a second medium to be maintained at a predetermined varying temperature difierential with respect to the first medium, including means in heat exchange relation with said second medium to be controlled for changing its temperature, means for controlling said means to maintain a progressively varying temperature differential between the two mediums including a temperature responsive power means responsive to the temperature of the first medium, a second temperature responsive power means responsive to the temperature of the second medium, the rate of change in power of the temperature responsive means being proportional to the change in temperature of the first medium and the corresponding desired change in temperature of the second medium, the difference in the rate of change in power of the two temperature responsive means being proportional to the predetermined varying temperature differential, said temperature responsive means being rigidly connected together in direct opposition to each other and being provided with means to control said means in heat exchange relation with said second medium.

3. A temperature regulating system for providing a temperature differential between a first medium having a fluctuating temperature and a second medium to be maintained at a predetermined varying temperature diflerential with respect to the first medium, including means in heat exchange relation with said second medium to be controlled for changing its temperature,

means for controlling said meansto maintain a progressively varying temperature differential between the two mediums including a temperasaid rigid connection for controlling said temperature changing means.

4. A temperature regulating system for providing a temperature difierential between a first medium having a fluctuating temperature and a second medium to be maintained at a predetermined varying temperature differential with respect to the firstmedium, including means in heat exchange relation with said second medium to be controlled for changing its temperature, means for controlling said means to maintain a progressively varying temperature differential between the two mediums including a temperature responsive power means providing power in a predetermined ratio to the temperature of the first medium, a second temperature responsive power means providing power in a difierent predetermined ratio to the temperature of the second medium, a rigid operating connection connecting said first and second power means, a switch means operated by both of said power means through said rigid connection for controlling said temperature changing means and yielding means acting upon said power means for providing a varying temperature difleren tial between the two mediums in addition to the differential provided by said predetermined ratios.

5. Refrigerating apparatus including an enclosure containing a medium, means for changing the temperature of said medium, means to control said means including means responsive to the temperature of the medium in said enclosure, and means responsive to the temperature of a medium outside of said enclosure, said means being rigidly connected together in direct opposition to each other and operable in a predetermined ratio upon said control means, whereby a temperature differential between said mediums can be progressively increased as the temperadetermined ratio to the temperature of a second equal to the resultant in power of said power air ments. 1

'7. A temperature regulating system for providing a temperature diiferential between two media, including means to vary the temperature of one of the media, means to control the temperature varying means including a first power element providing power in a predetermined ratio to the temperature of a first medium, a second power element providing power in another predetermined ratio to the temperature of a second medium, said power elements being connected to opposite ends of a common pivoted lever and providing power to said lever in an increasing resultant ratio when the temperature 01' one of said media. increases at a greater rate than the other of said media, said lever operating said temperature controlling. means to maintain a progressively increasing temperature difierential between said media...

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