US1929697A - Refrigerating apparatus - Google Patents

Description

Get. 10, 1933. J 3 ING 1,929,697

RE FRIGERAT I NG APPARATUS Original Filed Nov 30, 1927 2 Sheets-Sheet 1 Re "ism-0.1%

gmntoz Oct. 10, 1933. J. G. KING REFRIGERATING APPARATUS Original Filed Nov. 30, 1927 2 Sheets-Sheet 2 AAA gwvwntoc Patented Oct. 10,, .1933

PATENT OFFICE REFBIGERATING APPARATUS Jesse G. King, Dayton, Ohio, assignor, by mesne assignments, to Frigidaire Corporation, a corporation of Delaware Application November 30,

1927, Serial No.

236,718. Renewed September 12, 1932 4 Claims.

The present invention relates to improvements in refrigerating apparatus and more particularly the cold producing or refrigerating elements used in mechanically refrigerated cabinets.

It is an object of the present invention to provide an improved refrigerating element for relatively long cooling chambers such as the chambers of freezer counters and the like.

More particularly, it is an object of the invention to insure the circulation of refrigerant in a relatively long-and narrow refrigerating element. Usually a quantity of oil, used for lubricating the pumping apparatus for the refrigerant of the system, is conveyed to the refrigerating element and it is another object of the present invention to maintain a uniform stratification of oil and refrigerant in the refrigerating element so as to maintain substantially uniform evaporation of the refrigerant throughout the entire length of the refrigerating element.

In carrying out the above object, it is a further object to provide aplurality of ducts adapted to interconnect spaced headers, which ducts in themselves provide air passage ways and large heat absorbing surfaces and in addition are provided with fins for increasing such surface and these ducts are arranged so that interconnection is insured for every height of the liquid which may exist at any given time.

Further objects and advantages of the present invention will be apparent from the following description, reference being'had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 shows a side view of the improved refrigerating element;

Fig. 2 is a section of the refrigerating element taken on the line 22 of Fig. 1;

Fig. 3 is a view taken on the line 33 of Fig. 1;

Fig. 4 shows a side view partly in cross-section of the header taken on line 4-4 of Fig. 3;

Figs. 5 and 6 are diagrammatic views to illustrate the theory of operation;

Fig. 7 illustrates a .view of a refrigerated display case or counter taken on the line 77 of Fig. 8 and showing the counter provided with the improved refrigerating elements of the invention, and

Fig. 8 is an end view cross-section of the same.

In refrigerating elements of the elongated type consisting of a header and long ducts extending longitudinally therefrom, difficulty may. frequently be experienced in securing sufficiently rapid circulation of the refrigerant within the unit to produce efficient cooling.

In accordance with the present invention rapid circulation of the refrigerant is insured by using an additional header at a point remote from the main header and connecting the headers by means of .circulatory ducts arrangedin a manner which prevents dead-ending of any portion of the unit. 4

Referring in detail to the drawings it will be observed that the improved refrigerating element of the invention comprises a main header 10 and an auxiliary or additional header 11. These headers are connected by a duct system composed of individual pipes 12 and it is one of the primary features of the invention so to arrange these ducts that substantially continuous communication to the height of the unit will be constantly maintained. In operating a re-* frigerating element thus constructed the refrigerant and oil levels in both headers may be assumed to be equal at a given period of the operating cycle, the oil floating on the liquid sulphur dioxide. The refrigerant in the header 10 nearest the suction pipe will tend to evaporate faster than the refrigerant in the distant header and while the actual liquid levels of both may tend to seek a common elevation in accordance with hydrodynamic laws nevertheless the relative amounts of the constituent liquids of one header may vary from those of the other, so that after a short period of operation while bothliquid levels may be the same the header nearest the suction line e. g. header 10 will have a thinner layer of oil on top of its refrigerant than the remote header 11 and the refrigerant of the first will boil off faster than that of the latter causing the latter, distant header, to lag behind in cooling efficiency.

In the preferred embodiment of the invention the main header 10 and the auxiliary or secondary header 11 are connected by ducts or refrigerant and oil circulatory pipes 12 which are arranged in such a manner as to obviate the disadvantages above referred to. This is effected by so disposing the interconnecting pipes 12 that the effect is that of a large continuous header or pipe extending from the extremity of one header to the extremity of the other, without however sacriflcing in any manner the air circulation and eflicient cooling inherent to a multitubular structure of the type illustrated. It is obvious that such a result may be secured by using a series of header-connecting pipes superposed horizontally on each other and overlapping as shown in the theoretical diagram of Fig. 6 but it is also appar--- ent that such positioning of the tubes is physically impossible. The same result is however attained by staggering or alternating the tubes in the manner shown in Fig. 5 so as to produce the same practical effect as that theoretically attainable from thearrangement of Fig. 6. From an inspection of Fig. 5 it is obvious that pipe 7 is really intermediate pipes 1 and 2 and that it effect overlaps both of the latter ducts although it is located on the opposite side of a line drawn through the center of the cross-sectional plan of the header and pipe system. The same relationship holds for pipes 2, 3 and 6, the latter being intermediate and overlapping the former two. The three ducts at the top of the circle, 13, 9, 8 and the three at the bottom 3, 4, 5 overlap between themselves and of these no further explanation is believed necessary since the three top ones 13, 9, 8 serve practically exclusively for conveying gaseous refrigerant and the bottom ones conduct mainly a liquid. For all practical purposes substantially the same result is obtained in the arrangement illustrated in Figs. 2 and 3 even if the interconnecting tubes do not overlap to the same degree as shown in the theoretical example described.

As above stated liquid refrigerant is present in header 10 and is covered with a layer of oil, the level of the liquid in the header being controlled by a float valve 14. In the particular type of header illustrated by way of example, the inlet to the header is indicated by 15 and the suction end or outlet by 16. The stratified liquid will pass through the ducts 12 connecting the two headers and lie in the auxiliary header 11 at the same level as in header 10. The header 11 should always have exactly the same stratified (oil and refrigerant layer) composition as the body of liquid in header 10. As suction continues in header 10, however, the refrigerant therein is withdrawn together with some of the oil (the oil being circulated in the well known manner for lubricating the pumping apparatus). A certain degree of suction will be exerted on the liquid in header 11, but not to the same extent as in header 10, the gaseous refrigerant being drawn off through the upper ducts 13, 9, 8 and the result will be that the stratified liquid in the header 11 will yield some of its refrigerant to header 10, the said refrigerant passing over to the header 10 through the lower connecting tubes with the result that the oil in header 11 will tend to remain more or less ,constant in amount. With the arrangement of connecting pipes shown, however, the oil will find its way into header 10 through the staggered overlapping and alternating pipes which, as described above act after the fashion of a long continuous header body having no obstruction, the result being that the oil levels in both headers will be maintained equalized.

In order to facilitate the exchange of heat between the air and the 'ducts of the refrigerating element the connecting ducts are provided with fins 1'7. These fins are disposed transverse to the longitudinal axis of the element-that is, substantially parallel to the end walls of the headers and are spaced apart all along the length of the connecting ducts. These fins are preferably forced on the tubes or ducts and retained in place by means of small tubulures or flanges 18 punched out of the fins and if desired may be soldered or welded to the ducts to insure good thermal contact.

The improved refrigerating element of the invention comprises a unitary structure having spaced-apart headers, one of which is provided with means for controlling the liquid level in both, said headers being connected by a duct system adapted to permit unhindered transverse circulation of air and being provided with fins for improving the cooling and the circulation of Figs. 7 and 8 illustrate the improved refrigerating element of the invention mounted in operative relation in a commercial display counter cabinet or refrigerator. The cabinet itself comprises a structure having a substantially rectangular ground plan provided with a' bottom portion 19. The counter may be divided into a plurality of compartments such as a storage or machine chamber 20 and a food display compartment 21-, the latter of which may be provided with an impervious lining 22. The top 23 and the separatory wall 24 between the two compartments are suitably heat insulated as by means of corkboard 25 or the like. The side of the counter facing the customers and which may slantif desired is glazed in the well known manner, preferably with spaced glass panels 26 separated by insulating layers of air indicatedby 27. The rear of. the counter may be provided with doors 27, 28 which may if desired be glazed in a manner similar to the front windows so as to permit inspection of the contents of the case without opening the doors.

The refrigerating element is mounted within the display compartment by being suspended from the inside top as shown in Figs. 7 and 8. Straps 29 are clamped around the body of each header and the straps bolted to the ceiling of the compartment. A drip pan 31 is preferably disposed beneath the refrigerating element to catch water resulting frommoisture produced when the element is being defrosted.

.The drip pan may likewise serve as an air deflector or baffle plate for controlling and directing the circulation of the air cooled by the element. This drip pan or deflector plate may be suspended from members 30 and 32 bolted to the ceiling of the display counter after the fashion of the strap members 29 above mentioned. In the preferred embodiment of the invention two elements of the kind above described are used, the

main or control headers of the elements being disposed facing the ends of the case with the small auxiliary headers adjacent each other in the center of the case. A unitary arrangement with spaced apart headers is thus secured, and improved circulation of air effected.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Refrigerating meansfor mechanically refrigerated cabinets comprising a unitary structure including spaced headers, duct means connecting said headers, said duct means extending in the same direction as the bodies' of both headers, means operating automatically for maintaininga predetermined level of refrigerant in said duct means, and fins attached to said ducts in good thermal contact with said ducts.

2. Refrigerating means for mechanically refrigerated cabinets comprising a unitary structure' including spaced headers, duct means connecting said headers, said duct means extending in the same direction as the bodies of both headers, means operating automatically for maintaining a predetermined level of refrigerant in said duct means, and a plurality of fins attached to said ducts in good thermal contact with said ducts, said fins being disposed transverse to the longitudinal axis of said unit.

3. Refrigerating means for mechanically refrigerated cabinets comprising a unitary structure including ,spaced headers, principal heat absorbing means including duct means connecting said headers, said duct means extending in the same direction as the bodies of said headers, means for maintaining a predetermined level of liquid in said headers, a portion of the duct means being disposed above the level of refrigerant in the headers for conducting gaseous refrigerant from one of said headers to the other, another portion of said duct means being disposed below JESSE G. IQING.

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