US1750763A - Apparatus for refrigeration - Google Patents

Description

March 18, 1930. c. E. MoLEswoRTH Er'AL 1,750,763

APPARATUS FOR REFRIGERATION Filed Sept.. l2, 1927 JOHN Dl/.OMAN

C.6.ZO/rE/ T INVENTORS Patented Mar. 18, 193i) i UNITED y STATES PATENT oFElcE C'LYDE E. HOLESWORTH, JOHN DUDMAN, AND CARL G. ZOXELT, OF SEATTLE, WASHINGTON APPARATUS PQR REFBIGERATON Application led September 12, 1927. Serial No. 219,028.

This invention relates to refrigerating systems and more particularly to refrigerators of that class using a liquefied gas, such as anhydrous ammonia, or any other pre-cooled liquid, as the refrigerant; it being the principal object of the present invention to provide a practical and economical refrigerating system, especially for mercantile establishments and private home use, but suit- V ableyalso for other uses, which employs no pumps, compressors, motors, or the like, in its operation and which automatically miamtains a certain predetermined temperature within the refrigerated area. More specifically, 'the object of the present v invention resides in the provision of a refrigerating system using a volatile, liquid refrigerant, as above stated, which may bemaintained indefinitely in'its liquefied state by proper insulation of its container, with an expansion coillocated in the area to be refrigerated, and so connected with the container as to be supplied with the refrigerant by gravity fiow and only in accordance with the absorption of heat from the refrigerated area so as'to thereby automatically maintain a predetermined refrigerating temperature.

It is also an object of the invention to provide means Vwhereby the circulation of air 80 within the refrigerated area and about the expansion coils may be regulated as a means of determining the temperature within the refrigerated area and to insure its being evenly cooled.

Another object/ of the invention resides in the provision of means for retaining the expanded gas. l

Other objects of the invention residey in the various details of construction and particularly in the combination of parts, aswill hereinafter be described. u i

In accomplishing the various objects, we have provided the improved details of -con-A struction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Figure 1 is a vertical section taken transversely of a refrigerating system embodied by the present invention.

. the air within the refrigerating chamber from Figure 2 is a horizontal section taken substantiallyA on the line 2--2 in Figure 1.

Referring more in detail to the several views of the drawings- 1 designates, in its entirety, the Iefrigera- 55 tor body, or housing, which may be of a type and size convenient for mercantile or for household use, or may be made in .larger sizes for railway` car or other commercial purposes. In its preferred form for domestic 50 use, it would be of box-like form with its walls well insulated in the well-known, or any other suitable manner, so that its inside temperatures would be unaffected by temperatures outside. Within the top of the 5 refrigerator there is provided a compartment 2 within which a tank 3, or receptacle, containing the refrigerant 4, is located. Ac cess to this compartment may be had through a top opening 5 in the refrigerator within which a cover, or wall section, 6, is tightly and removably fitted, and access to the tank is provided for through a top opening within which a plug 3a is threaded.

Below the compartment 2, and separated therefrom by an insulating wall 7, is the refrigerating chamber 8 and located within the top of this chamber is a series of expansion, A or cooling, coils 9 consisting of relatively small pipes which, at their upper ends, conneet with a feed pipe 10 leading downwardly through an opening 7 in the partition wall 7 from the base of the tank 3 so that the liquid refrigerant -may flow by gravity from the tank into the coils. Preferably, these coils are arranged so as to enclose a rectangu! lar area, as shown in Figure 2, within which a frame structure l2 is supported 'for containing a plurality of trays 13 which may be slid into and from the same and within which water, or articles of food, may be placed for quick freezing. This freezing zone 8iis enclosed by a sheet metal housing 14 which is for the purpose of preventing coming into direct contact with the expansion coils with a resultant lowering of the temperature to a point far below that revquired or desired; also, for preventing excessive deposit of moisture in the form of 10 frost on the coils which would ultimately insulate them to a certain extent and also to prevent vapors or odors, from food or articles in the re rigerating chamber 8 from being absorbedby food products being prepared in the trays 13. The walls of the housing 14 are laced close to the coils 9 and this leaves a su stantial space between them and the side and top walls of the refrigerating chamber for the circulation of air.

As a means of controlling the circulation of air within the refrigerating chamber as a means of temperature control and also to ei'ect an even temperature throughout the chamber, we have fixed a perforated, sheet metal plate 15 in horizontal position and slightly spaced below the bottom lwall 14 of the housing 14 to provide an air circulating space, 16 between the two., The side edges of the late 15 terminate short ofthe side Walls of) the refrigerating chamber and these edges are adapted to be bent downwardly, as at 15 in Figure `1, so as to provide air pas-A sages 17 of widths or areas which, by experiment, are found to be correct for maintaining a certain predetermined temperature within the cooling area in the lower portion of the refrigerator; this degree of-temperature of course being dependent on the temperature made possible by the expansion coils and the rate of air circulationabout the expansion coils as determined by the area of the passages 17. Also, extending upwardly from the side edges of the plate 15 in parallel relation to the side and top Walls of the refrigerating chamber and also spaced therefrom and from the side and top' walls of the housing 14, are plates, or deectors, 20, which terminate in spaced relation at the top of the chamber. These walls provide that air circulating upwardly within the refrigerating chamber will, after passing through the passages 17. cont-inne upwardly along the sides and-top of the chamber walls and will then return downwardly over the topand side walls of the housing 14 and will be cooled by contact therewith and then distributed through the perforations of the plate 15 downwardly into the chamber, as indicated by the arrows in Figure l. This arrangement of baille plates retards the air circulation tc'rthat extent necessary for insuring a desired temperature with- 1n the refrigerating chamber and also effectsan even distribution of the cooled air to all parts of the chamber.

It will be mentioned here thatlaecessto the refrigerating chamber may be had through an opening 21 at the front of the refrigerator within which a door 22 is fitted, as indicated in Figure 2, and that suitable sl1elves,.as at 23, may be provided in the chamber; however, the details 4of construction of the housing itself and arrangement and number of doors used is not material to this invention so long.

serves as a trap for preventing the refrigerant from flowing into the filling pipe and wasting; it being apparent that gas confined in the upper portion of the pipe 25 will causethe liquid refrigerant t'o be backed u and retained back of the trap. Leading fiom the top of the tank 3 is a pipe 30 through which expanded gas may escape from tank 3 and be directed into a retaining tank 31, presently described in detail.

Assuming the device to be so constructed, its operation would be as follows:

First, the tank 3 is filled to a suitable depth with a liquefied gas, such as anhydrous ammonia, or any other suitable pre-cooled liquid; this being admitted to the tank through pipe 25, the expansion coils 9 and 10. Except at times when the tankis bein charged, the valve 26 is tightly closedin order to pre-l vent pressure within the tank from forcing the liquid out through pipe 25. Air within the housing 14, or freezing zone 8, is excessively cooled due to its intlmate relation with the coils 9. Air circulating within the refrigerating chamber 8 comes into contact with the walls of housin 14 which encloses the expansion coils 9 and reezinvr zone 8 and heat is ex` tracted froml this air hy reason of the lower tem erature within the housing.

Hleat thus transmitted from the air to the vcoils transforms some of the volatile refrig? erant into gas which bubbles up through the pipe 10 into tank 3 and passes oli' through pipe 30 vinto tank 31. The rate of this transformation of the refrigerant from liquid to j gas is, of course, controlled by the amount lof heat that can be extracted from the air and is dependent to a great extent on the rate of circulation ofair in contact with the housing 14. In the present instance, the rate of circulation and resultant temperature is con-l trolled by a proper determination of the area of the passages 17. It is readily understood placed within the refrigerating chamber for cooling, and this heat carried by the a1r 1s ultimately taken up by the coils 9 and 4absorbed in the gasifying of some of the refrigerant; the rate of which is in proportion to the amount of heat absorbed. It is further understood that, considering the tank 3 to be perfectly insulated, the refrigerant thereln will remain in its liquefied state indefinitely `that heat will be extracted from any article and it willbe suppned to the expansion coils only as required to replace that given up in the form of gas due to absorption of heat. lIt is apparent then, that the delivery of refrigerant to the coils is automatically controlled and is more, or' less, inproportion to the amount of heat absorbed by the coils from objects placed for cooling within the refrigerating chamber. If no heat can be extracted, no refrigerant. is used.

For the purpose of retaining the gas given olf from the container through pipe 30; we have provided thetank 31 which is partially filled with water or other absorbent. The pipe 30 o ens within the tank close to its base so that the gas from the pipe is caused to bubble into ,theabsorbent which retains it.

In the present illustration, a branch pipe l 35 connects with the pipe 30 above the tank 31 and this leads through a 3-way valve 36 into a pipe 37which opens into the top of the tank. Normally the valve 36 is adjusted so as to close passage through pipe 35 and to I connect pipe 37 with atmosphere.

When it is desired to empty the tank 31 of its contents, the valve 36 is adjusted so as to provide direct connection from pipe 3() to the top of the tank. Then the gas becomes confined under pressure in tank 3 and is released into the upper portion -of tank 31 and is utilized to expel the liquid from tank 31 through a discharge pipe 42 which leads upwardly from near the base' of the tank and through the top thereof. This latter pipe is provided with a water `level gauge 43 by means of which internal water level may be determined, and also is equipped with a valve 44 and a connection 45 to which a conduit, not shown, may be attached for filling or emptying the tank.

While we have described this system as arranged for domestic use, it is to be understood that thev same system can readily be adapted to commercial purposes, such as in railway cars, ships, refrigerating and .cold storage plants,l and we do not wish to confine itsscope only to the system shown.

Having thus described our invention, whatv weclaim as new therein and desire to secure by Letters Patent, is:

1. A device of the character described comprising an-"insulated housing providing an- Insulated compartment in the to portion thereof anda refrigerating cham er below saidcom Vartment, an insulated tank diS- posed wit in the top compartment for containinga supply of liquid refrigerant, a vent pipe leading. from the top of said tank, an ex ansion coil located within the top of the j re rigerating chamber having a pipe connection with the base ofthe refrigerant container through which the coil may be sup-` plied-by gravity flow and through which gas may be vented from vthe coils, a fillingdpipe, connected with thek baseof the coil tended upwardly to a point above the refrigerant container and a trap in said filling pipe adjacent its connectionwith the coil for preventing outward passage of the refrigerant.

2. A refrigeratbr of the character described comprising a housing providing an insulated compartment, in t e to vportion thereof and a refrigerating cham er below said compartment, a closed container disosed within the top compartment for' coning a,volatile liquid refrigerant, said container having a vent pipe leading from the top thereof, an expansion coil located within the top of the refrigerating chamber having a pipe connection at its top end with the base of the refrigerant container through which the coil may be supplied by gravity flow and through which gas may be vented from the coils, a filling pipe connected with the lower end of said coil having a trap therein adjacent its connection with the coil for preventing outflow of refrigerant, a housing inclosingthe coil in spaced relation from the walls of -the refilgerating chamber providing an interior freezing zone'and air deflect- 4ing plates suitably disposed within the re an expansion coil having a pipe connection with the container through which the coil may be supplied withrefrigerant by gravity flow and through which gas is vented from the coils into the container, of a closed tank for a gas absorbing liquid, a gas discharge pipe leading from the vent pipe connection of the refrigerant container into the said tank to a point below the liquid level therein, a pipe connection between the said gas discharge pipe and the top vof the tank, a valve in said pipe connection whereby direct communication may be made between the gas vdischarge pipe and the top of thetank, or with atmosphere, and a liquid discharge pipe leadinor from near the base of the tank through which the liquid may be forced by a pressure of gas delivered from the gas discharge pipe into the to of the tank.

Signed at Seattle, ashington, this 1st day of September, 1927. v

CLYDE E. MOLESWORTH.

JOHN DUDMAN.

CARL G. ZOKELT.

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