US1828566A - Automatic control for refrigerators - Google Patents

Description

Oct. 20, 1931. s. G. HOUSE ET AL AUTOMATIC CONTROL FOR REFRIGRATORSy Filed April 26. 1930 5 Sheets-Sheet l Oct. 20, 1931. s. G. HousE ET AL.

AUTOMATIC CONTROL FOR REFRIGERATORS 3 sheets-sheet 2 Filed April 26. 195o ATTOR N EY Oct. 20, 1931. s. G. HOUSE ET AL AUTOMATIC CONTROL FOR REFRIGERATORS Filed April 26. 1930 3 Sheets-Sheet 3 WITNESS @@W Patented Oct. 20, 1931 UNITED STATES PATENT -OFFICE SAMUEL G. HOUSE REX C. SNELLM1'.AMI, FLORIDA, ASSIGNORS, BY MESN'E AS- SIGNMENTS, TO AMERICAN REFRIGERATOR CAR COMPANY, OF MIAMI, FLORIDA, A

CORPORATION or FLORIDA' AUTOMATIC CONTROL FOR .'RIEIIEIRIGFIIQATOB Application led April 26, 1930. Serial No. 447,435.

This invention relates to an automatic control for refrigerators and is more particularlyadapted for use in refrigerator cars.

An object of the invention is the provision 5 of a device for controlling the flow of a refrigerating medium in a cooling unit of a refrigerating compartment through the expansion and contraction of the refrigerating medium, vthe control being effected at the in- 10 take side of the compressor in such a manner that the temperature maintained by the refrigerating mediuml being adapted to control a device which limits the flow of the refrigerating medium to the intake side of the compressor while permitting at all times a restricted flow to the intake.

Another object of the invention is the provision of a device for restricting the flow of the refrigerating medium to the com pressor of a refrigerating unit to prevent overload on the compressor; to relieve all restriction when the suction pressure becomes normal; to again restrict suction pressure when the desired temperature is obtained to prevent further refrigeration; and t permit the refrigeration to maintain an even temperature.

A further object of the invention is the provision of a dual control for a refrigerating unit which not only restricts the flow to the compressor to prevent overload on the compressor and to relieve all restriction when the suction pressure has become normal but to control the suction when the condenser coils are overheated or when the medium employed in the first control escapes and when the first control is rendered useless.

This invention will be best understood from a consideration of the following detailed description, in view of the accompanying drawings forming part of the specifica` tion, nevertheless, it is to be understood that the invention is not confined to the disclosure, being susceptible of such changes and lmodifications which shall define no material departure from the salient features of the invention as expressed in the appended claims.

In the drawings:

Figure l is a longitudinal vertical section of therefrigerator coil showing our invention applied thereto,

Figure 2 is a fragmentary plan view showlng connections between the axle of the refrigerating car and the compressor and connections between the motor for temporarily driving the compressor.

Figure 3 is a vertical section of a dual control for the refrigerating unit, Y

Figure 4 is a horizontal section take along the line 4 4 of Figure 3,

Figure 5 is a plan view of the condensing cois attached to the bottom of the freight car, an

Figure 6 is a vertical section of an automatic control between the condensing and expansion units of the refrigerator system.

Referring more particularly to the drawings, 10 designates a freight car having axles 11 and 12 secured to the usual iianged car wheels 13 which vellen drawn along the tracks (.not shown) caus rotation of the axles and l1kewise a pulley 14 secured to the axle 11. This pulley drives a second pulley 15 through a belt connection 16.

For the purpose of description, however, the pulley 15 is secured to a shaft 18 which in turn drives a pulley 19 whereby a belt 20 will drive the pulley 21 and likewise a shaft 22 which projects beyond the'"Hoi'lsingofy the transmission unit.

A shaft 23 is universally connected at 24 with a shaft 22 and is connected to a shaft 25 by a universal joint 26. A clutch 27 normally connects the shaft with a shaft 28 which drives the rotor or pistons of a compressor unit 29 having a header 30.

A shaft 28 may also be driven by means of a pulley 31, the pulley being driven by a belt 32 and a pulley 33 having direct connection with the shaft of an electric motor 34. This motor is provided with the usual wires 35 and an element 36 adapted to be connected with a source of current. A lever 37 is adapted to operate the clutch 27 which disconnects the shaft 25 from the shaft 28 to permit the motor 34 to drive the shaft 28 independently of its drivefrom the axle 11.

An outlet ipe 40 is connected with the header 30 of t e compressor 29 and also with the condenser coils 41 secured to the bottom of the freight car 10. These coils are disposed in a horizontal plane and are provided with removably mounted fins 42 which aid in coiling the coils as the air rushes through them when the car is moving. The extent of cooling depends upon the speed of the car and the temperature of the air in the regions through which the refrigerating car is passing. Clips 43 are adapted to connect the fins 42 to the sections of the coil 41.

A pipe 45 which is of restricted'diameter as compared to the coils 41 connects the extreme end of said coils with an expansion valve 46, more particularly illustrated in Figure 6. This expansion valve includes a casing 47 with which the pipe 45 is connected. A hollow boss 48 receives the threaded end of the pipe 45 and -is provided with a valve 50 n which has a stem 51 slidably mounted in a bearing 52 at a point on the housing 47 which is diametrically opposite the boss 48. A

spring 53 having one end in'engagement with a washer 54 secured'to the stem 51 and the 25 other end in engagement with a'portion of the wall of the housing 47 tends to maintain the valve in engagement -with its seat 49. `A yoke 55 in the form of a bell crank lever` and having an arm 56 pivotally mounted at 57 in the housing 47 straddles the stem 51 and is adapted to gage the washer 54 when the bell crank is oseclillated for vmoving the valve 50 away from its seat49l'as will be presently explained. A pressure responsive device is shown at 60 in the form of -a hollow bellows having a rigid base member 61. A lug 62 is secured to said base member and is pivotally connected with the arm 56. The upper end of the` bellows is secured, at 63, to the inner wall of the housing 47. This portion of the housing is provided with a hollow boss 64 which is in open communication with 'the chamber within the pressure responsive dvice`60. A spring 65 has one end secured to the bottom wall 61 of the member 60 and the other end to a rod 66.

A cup-shaped member 67 has a hollow boss 68 threaded into the hollow boss 64. The boss 68 provides communication between the member 60 and the cup-shaped member 67. The cup-shaped member has an annularflange 69 formed integrally with the walls of the cupshaped member and this flange has a central passage 7 0 through which is reciprocated the rod 66.

A casing 71 is threaded at 72 onto the outer wall ofthe cup-shaped member 67 and is provided with a plate 7 3 formed integrall with the casing at the upper end thereof.` pi e 74 has its free end connected with the plate 3 so that `a pressure responsive device in the form of a bellows 75 will be in open communication with the pipe. The lower end of the bellows has a rigid portion 76 which is sep C5 .'cured to the reciprocating rod 66 The housing 47 is in communication with a discharge pipe 80 connected to the end of an expansion coil 81 which is located within a refri erating chamber 82 at one end of the freig t car 10. A pipe 83 extends from the bottom of (the coil 81 along the floor of the car and, beneath a compartment 84 for the reception of comestibles and is connected to an expansion coil 85 located in a second re frigerating chamber 86 at the opposite end of the car. The coil 85 has a straight return portion 87 extending downwardly through the refrigerating chamber 86 outwardly through the bottom 87 of the car, as shown at 88, and is connected with a control box-89 in a manner which will be presently explained.

The pipe 74 extends along the top of the car and is connected with a pressure bulb 90 which is located approximately midway of the chamber 86 and in close association with the return pipe 87. The bulb 90 is filled with a predetermined quantity of methyl chloride so that when the temperature in the chamber 86 rises sufficiently the vapors from the methyl chloride will pass through the pipe 74 and enter the pressure responsive device 75 for a purpose which will bepresently explained.

A bulb 91 is located within the chamber 84 andV has a pipe 92 extending downwardly through the chamber 86 and beneath the floor 'of the car and is connected with the control box 89, as shown at 93.

The control box includes a pair of parallel chambers 95 and 96 which have their opposite ends open. The chamber- 95 is closed by means of a plate 97 which clamps the edge of the bellows or pressure responsive with a longitudinal passage 103 forming a guide for a valve stem 104 which is secured at 105 to the bott'om of the bellows 98. The stem is slidably mounted within a passage in the top 106 of the box 99. Saidfto 1s in the form of a disc threaded into said ox.

A valve 107 is secured to the stem 104 and is located within the box 99 and is adapted to be moved towards or away from the top 106 of the box. The top is rovidedwith a pluralit of passages 108 an a bleeder port 109 is a so included in the top. A spring 110 is in engagement with a washer 11,1 resting upon the top of the plug 102.' VThe other end of the spring engages the`underface of the valve 107 tending to move said valve towards the top 106 in order to close ythe passages 108. passage 112 connects a chamber 113 which is located between the bottom 114 of the bellows 98 and the top 106 of the cylindrical box 99.

Mounted within the chamber 96 is a bellows which is connected to the top ofthe box 99 by means of a plate 121 and a plug 122 provides means for securing the open end of a pipe 123. to the top of the box whereby the pipe is placed in communication with the bellows 120. As shown more particularly in Figure 1, the pipe 123 is in direct communication with the condensing coil 41 so that the bellows 120 will receive the refrigerating medium and will have the same pressure therein as do the coils 41. The bottom of the bellows 120 is provided with a `rigid member 124 which forms with the top 125 of a cylindrical box 126, a chamber 127. This chamber is in communication with a pipe 128 which forms the intake for the compressor 29.

A valve stem 129 is connected to the bottom `124 of the bellows 120 and is slidable in a passage in the top 125 of the box 126 and has its lower end guided by a hollow plug 130 threaded into a boss 131 formed on the bottom or base plate 132 of the box 126. This box is threaded at 133 to the lower end of the chamber 96.

A valve 135 is secured to the stem 129 and is located within the chamber 127 and is adapted to be moved into engagement with the top 125 of the box 126 for closing the ports 136 formed in said top. A bleeder passage 137 normally maintains the chamber 127 in communication with the box 126. A spring 138 rests upon a washer 139 supported by the inner end of the plug 130. The other end of the spring engages a disc 140 which is secured to the stem 129.

End walls 15() are secured in any approved manner within the car 10 and spaced from the outer end walls of the car to provide the ireciprocating chambers 82 and 86. A perforated bottom 151 is supported in the lower end of the car and spaced from the bottom in order to permit circulation of the cooled air in the car so that when the comestibles are supported on the member 151 the air will not only circulate through the perforations in the member 151 and through the comestibles but also beneath the member 151 and over the top edge of the end walls which are spaced from the top of the freight car.

The operation of my device is as follows: The cooling or refrigerating medium is supplied to the system in any approved manner and as long` as the car is remaining idle the compressor 129 will not be forcing the rerigerating medium. such as methyl chloride, under pressure into the condensing coils 41 and the temperature in the space 84 in the on. the refrigerating medium 1n t e condenser co1ls 14.

Due to the fact that the temperature in the n chamber 86 at starting is relatively high, the medium, such as methyl chloride, in the pressure bulb 90 will be expanded and act on the expansionchamber; 75, thereby causing the rod 66 to be moved yinwardly until it rests on member 69. The spring 65 will be compressed against the tension of spring 53 permitting valve 50 to o en sothat a quantity of the condensed re ri erating medlum will enterchamber 47 am? ex and until the ressure of the expanded me 'um overcomes t e pressure in the bellows 60 when the valve 50 will be closed by the spring 53. As soon as the suction in pipe 80 has increased suiiciently to reduce the pressure in chamber`47, the pressure in the chamber 60 will cause member 61 to move inwardly and rock the yoke 55 and o en valve 50. The expansion of the methyl c loride in these coils and in the pipe 83 will eventually reduce the temperature 1n both chambers 81 and 86 until the proper refrigerating temperature is had.

At the inltial operation of the pump 29 the temperature, as has been explained, in 95 the chamber 84 is at its maximum and the methyl chloride in the pressure bulb 91 will expand, causing the gas to exert a pressure within the expansible chamber 98 through the tube 92 and tend to retain thcvalve 107 0.

away from the ports 108 so that the suction end of the intake side of the compressor will be receiving the evaporated refrigerating medium for a continuance of the cycle of said medium through the system.

However, the pressure in the pipe 88 and chamber 113 will be the same as in the bellows 98. Since the compressor is operating, and because the pressure on both sides of the bottom`114 of the bellows is equalized the u.

spring 110 will close the valve 107. When the compressor is set in operation the pressure in the chamber 113 will be reduced sufticiently to permit the bellows 98 to open the valve 107 and the medium will be drawn on 11| its return to the compressor as long as the pressure in the bellows 98 is suiiicient to overcome the action of the spring.

When the 'temperature in the chambers 82 and 86 has been suiiiciently lowered or the 1g.

temperature reaches a degree which is desired, the medium in the pressure bulb 91 will be condensed as will be the medium in the pressure bulb 90. Thus the expansible chamber 75 will be contracted and through the various 125 elements permit the valve 50 to be moved towards closed position, thereby reducing the quantity of the refrigerating medium passing from the condensing coils 41 to the expansion coils 81 and 85. The lowering the temperal ture in the chambers 84 and 86 will causo contraction of the medium in the pressure bulb 91 so thatl the spring 110, shown more particularly in Figure 3, Will be permitted to move the valve 107 in close association with the closure plate 106 of the cylindrical member 99 and restrict the low of the refrigerating medium from the pipe 88 to the intake side of the compressor 29. If the tempera-- ture should be sufficiently lowered to cause the expansible member 98 to permit the valve 107 to be closed, a predetermined quantity of the refrigerating medium will pass from the pipe 88 into the cylindrical box 99, through the bleeder port 109, through the conduit 112 and through the cylindrical member 126, ports 136 and the pipe 128 to the intake side of the compressor.

The spring 110, the bleeder port 109 and the control by the pressure bulbs 90 and 91 are so regulated that predetermined pressures will be maintained in the refrigerating system at all times during the travel of the freight car. This travel Will permit, due to such regulation as previously explained, considerable variance in the speed of the freight car. v

If at any time it is necessary to sidetrack the car, for any purpose, the member 36, as shown 1n Figure 2, may be connected with a source of current for causing rotaton of the motor 34 and a pulley 31 after the clutch member 27 has been thrown out to disconnect the shaft 28 from the shaft 23. By this means the temperature of the car can be maintained uniform regardless of the length of time`it is sidetracked provided however that. the current is available.

When the freight car is travelling normally along the roadbed the belt 32 is disconnected from the pulleys 31 and 33 to prevent unnecessary operation of the motor 34.

The valve 135 comes into play when a dangerousl high temperature is maintained in the coo ing coils 41 for some reason. Certain of these reasons include the travel of the freight car through a region where the ground is extremely warm so that the cooling effect ofthe fins 42 on the coils is insullicient. At this time the high pressure in the coils 41 is transmitted through the pipe 123 to the expansible member 120 so that it will move 1n a direction to cause the valve 135 to be seated upon the member 125 which is threaded into the top of the cylindrical box 126. The port 137, however, ermits a predetermined quantity of the re igerating medium to pass to the pipe 29 and tothe intake side of the compressor. The closing of the valve 125 will prevent the greater portion of the refrigerating medium from being drawn into the compressor and thereby relieve the compressor of its load.

We claim:

1. In a refrigerating unit, a compressor,

condensing coils connected with the compressor, expansion coils having restricted communication with the condensing coils, a return pipe connecting the expansion coils With the intake of the compressor, a pressure control unit interpolated in the return pipe and including a valve, means associated with the expansion coils for actuating the valve for restricting the return of a refrigerating medium from the expansion coils to the compressor in accordance with a drop in temperature of the medium surrounding the expansion coils.

2. In a refrigerating unit, a compressor, condensing coils connected with the compressor, an expansion coil having a restricted communication withthe condensing coils. a. second expansion coil directly connected with the first expansion coil, a return pipe connecting the second expansion coil with the compressor, a pressure control unit interpolated in the return pipe and including a valve, means associated with the expanson coils for actuating the valve for restricting the return of a refrigerating medium from the expansion coils to the compressor in accordance with a drop in temperature of the medium surrounding the second mentioned expansion coil.

3. In a refrigerating unit, a refrigerating chamber, compressor, condensing coils located exteriorly of the chamber and connected vWith the compressor, expansion coils in communication with the condensing coils, a return pipe connecting the expansion coils with the intake side of the compressor, a pressure control unit interpolated in the return pipe and including a pair of valves, means associated with one of the expansion coils for actuating one of the valves in accordance with a drop in temperature of said expansion coil for restricting the ilow of the refrigerating medium from the expansion coils to the intake side of the compressor, means responsive .to excessive pressure in the condescending coils for restricting communication between the expansion coils and the intake side of the compressor.

4. In a refrigerating unit, a compressor, condensing coils connected with the compressor, expansion coils having restricted communication with the condensing coils, a return pipe connecting the expansion coils with the intake of the compressor, a pressure control unit interpolated in the return pipe and including a valve, means associated with the expansion coils for actuating the valve for restricting the return of a refrigerating medium from the expansion coils to the compressor in accordance with a drop in temperature of the mediumsurrounding the expansion coils, the pressure control unit being provided with a bleeder port permitting a restricted flow of the refrigerating medium around the valve when said valve is closed.

5. In a refrigerating unit, a refrigerating chamber, a compressor, condensing coils located exteriorly of the chamber and connected with the compressor, expansion coils in communication with the condensing coils, a return pipe connecting the expansion coils with the intake side of the compressor, a pressure control unit-interpolated'in the return pipe and including-a pair of valves, means associated with one of the expansion coils for actuating one of the valve in accordance with a drop in temperature of said expansion coil for restricting the flow of the refrigerating medium( from the expansion coils to `the intake side of the compressor, means responsive to excessive pressure in the condensing coils for restricting communication between the expansion coils and the intake side of the compressor, said pressure control unit being provided with a bleeder port associated With each valve to permit a restricted iiow of the refrigerating medium from the expansion coils to the intake side of the compressor.

6. In a refrigerating unit, a refrigerating chamber, a compressor, coils located exteriorly of the chamber and connected with the compressor, expansion coils in communication with the condensing coils, a return pipe connecting the expansion coils with the intake side of the compressor, a pressure control unit interpolated in the return pipe and including a pair of valvesfmeans associated with one of the expansion coils for actuating one of the valves in accordance With a drop in temperature of said expansion coil for restricting the flow of the refrigerating medium from the expansion coils to the intake side of the compressor, means responsive to excessive pressure in the condensing coils for restricting communication between the expansion coils and the intake side of the compressor, said pressure control unit being provided Wth bleeder ports for maintaining a restricted flow of the refrigerating medium to the intake side of the compressor from one of the expansion coils when either or both of the valves are closed.

7. In a refrigerating unit, a compressor, a condenser connected with the compressor, al1 expansion chamber having controlled communication with the condenser, a pressure control unit connected with the expansion chamber, a pipe connecting the unit with the intake side of the compressor, said unit including a valve for controlling the iovv of a refrigerating medium from the expansion chamber, a temperature responsive device having means subject to pressure of the intake slde of the compressor for controlling the valve.

8. In a refrigerating unit, a compressor, a condenser connected with the compressor, an expansion chamber having controlled conimunication with the condenser, a pressure control unit connected with the expansion chamber, a pipe connecting the unit with the intake side of the compressor, said unit including a valve for -controlling the low of a refrigerating medium from the expansion chamber, a temperature responsive device having means subject to pressure of the intakel side of the compressor for controlling the valve, said unit including a bleeder port for maintaining the expansion chamber in restricted communication with the intake side of the compressor.

9. In a refrigerating system, a compressor, means for controlling the intake side of the compressor and comprising a chamber, a partition dividing the chamber into a pair of sections and provided with ports for placing the sections in communication with each other, a valve for closing said ports, an expansible member carrying a valve stem to which the valve is secured, one of the sections being in open communication with the expansion chamber of the system, the other section being in communication with the intake sides of the compressor, a temperature responsive means in a refrigeratng compartment of the system subjecting the expansible member to pressure for opening the valve, and a. spring tending to close the valve, the expansible member being subject to pressure from the intake side of the compressor, such .pressure co-operating with the spring and pressure Within the expansible member to control the valve.

l0. In a refrigerating system, a compressor, means for controlling the intake side of the compressor and comprising a chamber, a partition dividing the chamber into a pair of sections and provided with ports for placing the sections in communication with each other, a Valve for closing said ports, an expansible member carrying a\ valve stem to which the valve is secured, one of the sections being in open communication with the expansion chamber of the system, the other section being in communication with the intake sides of the compressor, a temperature responsive means in a refrigerating compartment of the system subjecting expansible member to pressure for opening the valve, and a spring tending to close the valve, the expansible member being subj ect to pressure from the intake side of the compressor, such pressure co-operating with the spring and pressure'within the expansible member to control the valve, ,said partition having a bleeder port for -retarding the closing or opening of the valve While maintaining the expansion chamber of the system in restricted communication with the intake side of the compressor.

11. In a refrigerating system, a compressor, means for controlling the intake side of the compressor and comprising a chamber, a partition dividing the chamber into a pair ino izo

6 Y Lezama of sections and provided with ports for placin the sections in communication with each ot er, a valve for closing said ports, an expansible member carrying a valve stem to 5 which the valve is secured, one of the sections being in open communication with the expansible member of the system, the other section being in communication with the intake sides of the compressor, a temperature l responsive means in a refrigerating compartment of the system subjecting the expansible member to pressure for opening the valve, and a spring tending to close the valve, the expansible member being subject to pressure l from the intake side of the compressor, such pressure (2o-operating with the spring and pressure within the expansible member to control the valve, and means' for varying the pressure on the s rin 0 SALiMUL G. HOUSE.

REX SN ELL.

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