US 3067589 A
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Description (OCR text may contain errors)
Dec. 11, 1962 D. H. DENNIS EI'AL COOLING APPARATUS Filed Nov. 8, 1960 a' lB United States Patent Ofilice 3,067,589 Patented Dec. 11, 1962 3,067,589 CGDLING APPARATUS David H. Dennis, hort Hills, and Lester V. Hebenstreit, Bloomfield, Nail, assignors to Specialties Development Corporation, Belleville, NJ., a corporation of New Jersey Fiied Nov. 8, 1968, Ser. No. 68,078 6 Claims. (Cl. 62293) The present invention relates to refrigeration, and, more particularly, to apparatus for maintaining an element at a much lower temperature than the ambient temperature.
It has been found that certain electrical components such as photocells, particularly infrared cells, can be operated more efficiently at a temperature of about il F. or lower, because at such temperatures the sensitivity of the cell is increased and the noise to signal ratio of the cell is greatly decreased.
It has thus been proposed to maintain such cells at a low temperature by expanding a compressed gaseous medium such as air or nitrogen in the vicinity of the light sensitive element of the cell whereby the medium is refrigerated due to the Joule-Thomson effect in conjunction with counterflow heat exchange. More specifically, such apparatus include a coil of tubing through which the compressed gas was directed and the expanded cool medium was caused to counter-flow in heat exchange relation to precool the compressed gas.
For aircraft installations or otherwise, where space and weight are important factors, the use of air or nitrogen was not practical because either a relatively heavy compressed gas storage receptacle or a gas compressor system was required as the source of the medium. Also, the compressed gaseous medium must be completely dry to prevent the formation of water ice which might block the flow of the medium, wherefore further apparatus had to be added to dry the gaseous medium.
In order to reduce the weight of the apparatus, refrigerants such as liquefied carbon dioxide have been used because of their greater storage density and their greater cooling capacity on a mass basis than air or nitrogen.
Accordingly, the primary object of the present invention is to provide improved cooling apparatus utilizing a refrigerant which is extremely light in weight, simple in construction, and economical to manufacture, and is efficient and reliable in operation.
Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.
A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawing, forming a part of the specification, wherein:
FIG. 1 is a longitudinal sectional view of cooling apparatus in accordance with the present invention.
FIG. 2 is an enlarged fragmentary sectional view of a detail of the apparatus.
FIG. 3 is a sectional view taken along the line 3-3 on FIG. 2.
FIG. 4 is an enlarged fragmentary sectional view of another detail of the apparatus.
Referring now to the drawing in detail, there is shown apparatus which generally comprises a receptacle for storing a refrigerant under pressure, a tube 11 attached to the receptacle having an open end 12 and a closed end 14 adapted to be opened, an expansion chamber 15 for confining the open end 12 of the tube 11, and a second tube 16 in heat exchange relation with the tube 11 having a first open end 17 and a second open end 18 in fluid flow communication respectively with the interior of the receptacle 10 and the chamber 15.
In the illustrative embodiment, the receptacle 10 is a small generally cylindrical cartridge adapted to contain about 0.3 ounce of liquefied carbon dioxide, and has a closed end 19 and a neck 20 formed with an opening 21 which is sealed by an inverted hat-shaped closure 22 preferably spot welded within the opening 21. The closed end 19 of the receptacle and the central portion of the closure 22 are formed with apertures 24 and 25 respectively through which the tube 11 extends. The tube 11 is secured and the apertures 24 and 25 are sealed by silver braze applied about the tube 11 at the exterior thereof adjacent the apertures.
The end 14 of the tube 11 preferably is closed by crimping and spot welding the same at 26, whereby the end portion of the tube 11 can be broken off at 26 to open the tube at the end 14.
The chamber 15 (FIG. 2) is provided by a cup-shaped member 27 having an end wall 28 which is positioned against the element (not shown) to be cooled, and a plug 29 secured and sealed within the open end of the member 27 having an aperture for securement and sealing of the end 12 of the tube 11 therein.
The tube 16 is of capillary dimensions and extends at least partially through the bore of the tube 11. The open end 17 extends through a side wall opening 30 (FIG. 4) in the tube 11 and is sealed therein and the open end 18 extends into the chamber 15. Preferably, the end portion of the tube 16 within the chamber is bent at right angles and is curved at 31 to direct expanded refrigerant in a circular path (FIGS. 2 and 3).
In the event the refrigerant utilized is carbon dioxide or another which forms snow-like particles when expanded, a fine screen 32 is mounted within the chamber member 27 between the open end 18 of the tube 16 and the open end 12 of the tube 11 so that the particles are retained in the chamber 15 near the end wall 28 but gas can exit by way of the tube 11.
The apparatus shown herein is charged with refrigerant through the tube 11 at the end 14 before the tube is crimped at 26 by passing the refrigerant into the chamber 15 and then back into the receptacle 10 by way of the tube 16 in a controlled manner so that in the case of carbon dioxide expansion of the refrigerant within the chamber 15 does not produce snow-like particles. After the receptacle has been charged with refrigerant, the tube 11 is crimped and welded as previously indicated to confine the refrigerant.
In use, upon breaking or shearing the tube 11 at 26 to open the same, refrigerant flows from the receptacle through the tube 16 to the chamber 15 where it is expanded to produce a cooling efiect on the end wall 28, and cold expanded gaseous refrigerant exits through the tube 11 to atmosphere while cooling the refrigerant passing through the tube 16 to increase the Joule-Thomson effect of the refrigerant.
From the foregoing description, it will be seen that the present invention provides extremely simple and practical cooling apparatus which can be manufactured economically, is readily installed in a small space, and is reliable in operation to produce an efiicient cooling effect.
As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.
1. In cooling apparatus, the combination of a sealed storage receptacle for confining a refrigerant under pressure, a tube attached to said receptacle in heat exchange relation therewith and having an open end and a closed end adapted to be opened to communicate directly to a mo ph re, n expan on h m er c fi i s id p end of said tube, and a second tube extending in heat exchange relation at least partly through said first mentioned tube having first and second open ends in fluid flow communication wtih the interior of said receptacle and chamber, respectively.
2. In apparatus according to claim 1, wherein said first mentioned tube extends through and outwardly of said receptacle.
3. In apparatus according to claim 1, wherein said receptacle is generally cylindrical and said first mentioned tube extends lengthwise through and outwardly of said receptacle.
4. In apparatus according to claim 1, wherein said first mentioned tube has a crimp at its closed end to close the same and is adapted to be broken at the crimp to open the same.
5. In apparatus according to claim 1, wherein said second open end of said second tube extends into said chamber beyond the open end of said first mentioned tube, and a screen is positioned in said chamber between said second open end of said second tube and the open end of said first mentioned tube to confine solidified refrigerant within said chamber.
6. In cooling apparatus, the combination of a sealed storage receptacle for confining a refrigerant under pressure, an expansion chamber, a tube having first and second open ends in fiuid fiow communication with said receptacle and said chamber respectively, a second tube in heat exchange relation with said first mentioned tube and said receptacle and having an open end in fluid flow communication with said chamber and a closed end adapted to be opened for fluid flow communication to atmosphere, and a screen positioned in said chamber for confining solidified refrigerant within said chamber.
References Cited in the file of this patent UNITED STATES PATENTS 1,586,029 Cremieu May 25, 1926 2,645,097 Posch July 14, 1953 2,898,747 Wales Aug. 11, 1959