US2172916A - Temperature control in refrigerating or cooling apparatus - Google Patents

Description

P 2, 1939 J. F. B. \VIIDAL 2,172,916

TEMPERATURE CONTROL IN REFRIGEFATING OR COOLING APPARATUS Filed April 21, 1938 3 Sheets-Sheet 1 MIME/V701? haam M4,. I

Sept; 12, 1939. J. F. B. VIDAL TEMPERATURE CONTROL IN REFRIGERATING OR COOLING APPARATUS '3 Sheets-Sheet 2 Filed April 21, 1938' m ME j gun.

J. F. B. VIDAL Sept. 12, 1939.

TEMPERATURE CONTROL IN REFRIGERATING OR COOLING APPARATUS Filed April 21,- 1938 5 Shets-Sheet 5 Patented Sept. 12, 1939 PATENT OFFICE TEMPERATURE CONTROL IN REFRIGER- ATING OR COOLING APPARATUS John Furse Bancroft Vidal, Purle Stone & Company,

signor to J.

ford, England, a company of Application April 21,

In Great Britain April 22,

4 Claims.

This invention comprises improvements in and connected with temperature control in refrigerating or cooling apparatus and particularly in refrigerator chambers adapted for use in vehicles, railway carriages, vans and the like.

The principal object of the present invention is to improve automatically controlled refrigerator installations which are self-contained and which dispense with the employment of any outside or auxiliary power means for the operation of the control devices.

In these installations a refrigerant container is arranged in a heavily insulated box or chamber having controlled communication with the cold storage space, .such communication being regulated or shut-off by shutters, doors or other valve-like means. The partial or complete closing of such shutters has the efiect of reducing or stopping the circulation of relatively warm air from the cold storage chamber past the refrigerant container, thereby slowing down or arresting the evaporation of the refrigerant.

Apparatus for temperature control according to this invention comprises a container for vaporizable refrigerant and adapted for withstanding pressure, a diaphragm or bellows device adapted for being flexed" by pressure admitted from the container, temperature-responsive means operative for controlling pressure admission to the diaphragm or bellows device, and a shutter device operatively connected with the diaphragm or bellows and effective for regulating air circulation past the container.

In order to enable the invention to be readily understood reference is made to the accompanying drawings, wherein:

Figure 1 is a more or less diagrammatic cross sectional view of a vehicle body fitted with one example of refrigerating apparatus in accordance with these improvements.

Figure 2 is a diagrammatic representation of another example.

Figure 3 is a longitudinal sectional elevation of the roof of a railway vehicle fitted with re- 45 frigerating apparatus similar to that seen in Figure 2.

Figure 4 is a cross section of Figure 3.

Figure 5 is a sectional elevation to a larger scale of the pressure device and linkage seen in Figure 3.

Referring to Figure l, a represents a cold storage chamber or insulated vehicle body and b a heavily insulated compartment atone side or end of such chamber or body. The compartment b has a relatively large opening at the bot- England, as- Limited, Dept- Great Britain 1938, Serial No. 203,428

tom communicating with the cold storage chamber a and in this opening are fitted louvre shutters c or other suitable doors or valves. The compartment b also has a relatively small opening d at the top communicating with the top 5 space of the cold storage chamber a. Within the chamber b is suitably supported a C02 container e which is preferably provided with heat exchange fins or the like and is hermetically closed and adapted for sures. It is provided with a blow-off valve 1' which may be adjusted to limit the pressure in the container e say to about five pounds per square inch. A gas pipe 9 is led from the container to a heat exchange device h, such as a 15 coil, disposed externally of the cold storage chamber a and serving as a pre-heater. From the coil h a gas pipe 9' passes to a suitable power element which may take the form of an expansibie diaphragm or bellows device 7a which is appropriately linked with the louvre shutters c for operating the latter. In the pipe I there is a. valve at l in operative connection with a thermostat m disposed within the cold storage chamber a; The thermostat m may be a bulb containing a suitable fluid and the valve at I may be a needle valve operatively connected with a diaphragm or piston under the influence of pressure changes due to expansion and contraction of the fluid in the bulb m. The diaphragm device k is fitted with a restricted leakage vent which may take the form of a small tube fitted with a valve k the last named being adjusted to permit of a suitable rate of pressure leakage from the diaphragm chamber.

The operation will now be apparent. The storage chamber a having been closed after the introduction of goods, air will circulate through the cold compartment b, the warm air from the chamber a entering at d and descending, upon 40 being cooled by the CO2 container e, so that an outflow of cold air from b to a past the open louvres c is effected. The heat exchange between such air and the container e causes evaporation of the CO2 so that a pressure is developed within the container, such pressure being limited by the blow-ofi valve I. When the circulation of cold air has reduced the temperature within the storage chamber a to the desired degree, the thermostat m produces an opening of the valve at I so that pressure gas passes to the power element is which thereupon operates to move the shutters 0 towards the closed position, thereby throttling the circulation and reducing the rate of evaporation in the container e. The

withstanding low presvalve 1 and power element It cannot be hindered in operation by freezing or condensation, because the gas has been warmed in the preheater coil 71. before passing to them. When the temperature has been reduced to a value within the prescribed limits, the thermostat 122. may produce a complete closure of the shutters 0 so that circulation of cold air and evaporation of CO2 are arrested. In this condition, the top opening d may permit of a little spillage of cold air from time to time from the compartment b into the chamber a. Reverse action of the thermostat may operate to shut off the flow of gas to the pressure device 10 and to relieve the pressure therein. However, in the example illustrated in Figure 1, the leakage at whilst slow enough to maintain an operating pressure in the device It during operation of the latter, is suflicient for exhausting the space behind the diaphragm in reasonable time when the valve at Z is closed by the thermostat. In the foregoing it has been assumed that the shutters c are self-opening, as by providing them with spring or gravity means for that purpose, and that pressure is admitted to the device It for closing them. However, the shutters 0 might equally be self closing and the pressure admitted to the device It for opening them.

The modified arrangement in Figure 2 difl'ers from that in Figure 1 principally in regard to the shutter devices. In Figure 2, the CO2 container e is a shallow vessel having a shallow V-shaped bottom fitted with heat exchange fins c, this container being fitted in a roof space and fragments of roof fittings being indicated at r and T The shutters consist of a pair of angle plates 0 0 each plate being mounted on a rock shaft 8 at the apex of its angle. In the closed condition of the shutters, illustrated in full lines in Figure 2, each plate part c rests against a roof fitting r or r and each plate part c rests against a trough t extending along beneath the container 6 and adapted for collecting moisture which condenses upon the bottom of the container and runs down to the middle drip point above the trough. The closed container 2 is connected by a pipe g with a valve casing n, the blow-01f valve f being on the pipe in this case. Admission of gas from the pipe 9 to the casing 11 is controlled by a valve 0 which is operatively connected with a diaphragm or piston device in a chamber n the last-named being connected by a tube with the thermostat bulb m. The valve casing n is connected by-a pipe with the pressure device It, the diaphragm of the latter being connected by a link 1) with a two-armed lever q. The top arm of the lever q is connected by a link it with the lower arm of a two-armed lever 12, the upper arm of this lever being connected with the plate part c of the right hand shutter. The lower arm of the lever q is connected by a link u with the lower arm of a two-armed lever 0 the upper arm of this lever being connected with the plate part c of the left hand shutter. When the temperature influencing the bulb m rises, the pressure due to expansion of the fluid becomes operative in the chamber n for opening the valve 0. Thereupon, gas is admitted to the device It to dilate the diaphragm thereof.

The consequent push on the link 21 causes the three levers q o and v to be rocked to the dotted line position with the result that the shutters 0 .0 are rocked to an open position shown in dotted lines. In this open position, relatively warm air at the roof can pass over the top edges of the shutters to become cooled in contact wit! the CO2 chamber e whereupon this air descends between the bottom edges of the shutters and the trough t, as indicated by the dotted arrows in Figure 2.

Figures 3 and 4 show apparatus similar to that of Figure 2 as it appears when installed in the roof of a vehicle, and in Figure 3 it will be seen that the shallow container e may be of considerable length so that it extends along the roof. The container e may be charged with blocks of CO2 through hand holes in the roof, these being closable gas-tightly by means of plugs or covers a: held down by fastening means :0 Figure 4 shows the shafts s supported by brackets 1/ from the roof fittings r r and the trough t, which is drained by a pipe t suspended by small plates 2 from the CO2 container. It will be clear from Figures 3 and 4 that the shutters c c are co-extensive with the container e along the roof, the pressure device It for operating them being shown to the right-hand side of Figure 3 together with the linkage through which it opcrates, which linkage will be described in detail with reference to Figure 5.

Referring to Figure 5, the left hand shaft s is fitted with an upwardly extending arm I and the right hand shaft 8 is fitted with a downwardly extending arm 2, the arms I and 2 being interconnected by a link 3 of adjustable length. This interconnection ensures simultaneous and opposite turning of the shafts s, as is necessary for producing the movements of the shutters c 0 already described. The right hand shaft s has fixed to it an arm 4 which has a pin and slot connection with one end of a lever arm 5, the pin being insertable into any one of a number of holes to provide a rangeof adjustment. The lever arm 5 is pivotally mounted at its opposite end in a hanger 6 suspended from the pressure device It, the latter being suspended from the roof by brackets 1. A disc 8 attached to the diaphragm of the pressure device has a boss at its centre which is connected with the lever arm 5 by means of a divided screw threaded rod 9, the parts of the latter being united by a screw threaded coupling sleeve III which can be turned to adjust the length of the rod. Referring to Figures 4 and 5, it willbe apparent that dilation of the diaphragm will depress the rod 9, Figure 5, and the lever arm 5, thereby turning the right hand shaft s counterclockwise and the left hand shaft 3 clockwise to effect opening of the shutters c c Figure 4. The operation of the similar apparatus in Figure 2 having already been described, further description of the apparatus in Figures 4 to 6 is thought to be unnecessary.

I claim:

1. Refrigerating or V cooling apparatus comprising an evaporative refrigerant container capable of withstanding pressure, a power element having a diaphragm adapted to be flexed by pressure fluid supplied to said element from the container, a pipe connecting said container with said power element, a shut-off valve in said pipe, temperature-responsive means operative on said valve for controlling pressure admission to the power element, and a shutter device operatively connected with the diaphragm of said power element for regulating circulation past the container,

2. Refrigerating or cooling apparatus comprising an evaporative refrigerant container capable of withstanding pressure, a power element having a diaphragm adapted to be flexed by pressure fluid supplied to said element from the container, a pipe connecting said container with said power element, a shut-oif valve in said pipe, temperature-responsive means operative on said valve for controlling pressure admission to the power element, said pipe being formed with a heat exchange coil, and a shutter device operatively. connected with the diaphragm of the power element for regulating air circulation past the container.

3. Refrigerating or cooling apparatus comprising an evaporative refrigerant container capable of withstanding pressure, a leaky power element having a diaphragm adapted to be flexed by pressure admitted from the container, said leak permitting return of the diaphragm to normal when pressure admission is shut off, a pipe connecting said. container with said power element, a shut-off valve in said pipe, temperature- 2 responsive means connected to operate said valve for controlling pressure admission to the power element, and a shutter device operatively connected with the diaphragm of the power element for regulating air circulation past the container.

4. Refrigerating or cooling apparatus comprising an evapor'ati've refrigerant container capable of withstanding pressure, a power element having a diaphragm adapted to be flexed by pressure admitted from the container, a pipe connecting said container with said power element, a shut-off valve in said pipe, temperature-responsive means connected to operate said valve for controlling pressure admission to the power element, a pair of rock shafts, a pair ofangle plates each mounted at the apex of its angle on one of said rock shafts respectively, said ro'ck shafts and angle plates being operatively connected with the diaphragm of said power element for regulating air circulation past the container.

JOHN FU'RSE BANCROF'I' VIDAL. 20

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