US2117861A - Evaporator for refrigerating machines - Google Patents

Description

May 17, 1938. c. sTEl-:NsTRUP EVAPORATOR FOR REFRIGERATING MACHINES Filed Aug. 29, 1956 3 3 r \\l \\H/ \\I|Ml/ \\l/ l/ T Q 4 Z. n \J A y/ Attorney.

Patented May i1, 193s 2,112,861

AUNITED STATES PATENT OFFICE cin-nnen Steenstrup, Schenectady, N. y., aeslgnor to General Electric Company, a corporation of New York 'Application August 29, 1936, Serial No. 98,456

3 Claims. (Cl. 62-126) My invention relates to evaporators or cooling a cylindrical header 20 from which it is withunits for refrigerating machines. drawn through a suction conduit 2l and is re- It is an object of my invention to provide an turned to the casing I4. 'I'his cycle of operation improved evaporator of the flooded type for recontinues as long as thecompressor Within the 5 frigerating machines, having a header and a plucasing is operating. The temperature within the 5 rality of U-shaped depending refrigerant clrcucompartment II is regulated thermostatically in lating passages and having an improved arrangethe usual manner by controlling the operation ment for providing a rapid and efficient positive of the motor which drives the compressor Within circulation of liquid refrigerant through the pasthe casing I4. sages thereof. In evaporators of the flooded type it is desir- 10 Another object of my invention is to provide an able to provide some arrangement for producing improved evaporator of the flooded type for rea rapid circulation of liquid refrigerant and a frigerating machines which shall provide a posirecirculation of liquid refrigerant from the header tive and eicient circulation of liquid refrigerant through the refrigerant circulating passages. An with a minimum of turbulence within the header. increased rate of circulation of liquid refrigerant 15 Further objects and advantages of my invenincreases the rate of absorption of heat and, contion will become apparent as the following desequently, provides an evaporator which will cool scription proceeds, and the features of novelty the surrounding air more lrapidly and will also which characterize my invention will be pointprovide for rapid freezing of water, desserts and zo ed out with partioularity in the ciaims annexed to the like. I attain these advantages by constructand forming a part of this specification. ing the evaporator of two sheets of metal having For a better understanding of my invention, indentations formed therein to provide a header reference may be had to the accompanying drawand a plurality of depending U-shaped refriging in which Fig. 1 shows a household refrigerator erant circulating passages or conduits and an ar utilizing an evaporator embodying my invention; rangement whereby the refrigerant supplied to 25 Fig. 2 is an enlarged perspective view of the the evaporator is utilized to produce a positive evaporator shown in Fig. 1; and Fig. 3 is a plan circulation of liquid refrigerant to the header and view of the sheet metal portions of the evaporator a recirculation from the header in a predetershown in Fig. 1 prior to bending. mined direction. Portions of the U-shaped reso Referring now to the drawing, in Fig. 1 I have frigerant passages are preferably arranged in 3o shown a household refrigerator comprising a a horizontal plane to provide a surface for Supcabinet iu having a food compartment Il and a porting freezing trays which afford rapid freezdoor I2 for closing the compartment. The coming 0f Water, desserts and the like. partment II is cooled by an evaporator or cooling Referring 110W t0 Fig. 2, the evaporator I3 iS unit I3 arranged in the upper portion thereof and made of inner and outer sheet metal portions 22 35 supplied with refrigerant from a refrigerating and 23 respectively. The Sheets 22 and 23 are machine mounted on the top of the cabinet. The made of stainless steel or other suitable material refrigerating machine comprises a closed casand are provided With indentatOnS 01 Corrugaing I4 in which is arranged a motor and a retions forming the cylindrical header 20 adjacent 40 frigerant compressor, an air cooled refrigerant the upper endS 0f the Sheets, a plurality 0f 40 condenser I5 comprising a conduit I6 and a float separate U-shaped depending conduits 25, a valve chamber I'I. During the operation of the sinuous conduit 26, a mallfOld 2l and a plurality motor and compressor within the casing I I of ducts 28 connected to the manifold 2l and the gaseous refrigerant is compressed and discharged lower portions of the U-shaped passages 25. The into the conduit I6 of the condenser I5 where upper ends of the U-shaped passages all com- 45 it is cooled by air circulating over the condenser municate with the lower portions of the header due to the natural drafts, and is liquefied. The 20 and are all arranged Substantially in 10I1giliquefied refrigerant then ows through a contudinal allnement. The sheets 22 and 23 are nection I8 to the float valve chamber I'I. When bent to form side walls 29 and 30 and top and a. predetermined amount of liquid refrigerant has bottom Walls 3l and 32 respectively, providing 50 collected in the chamber I1 a float arranged upper and lower surfaces Bla and 32a for suptherein rises and admits refrigerant to the evapoporting freezing trays and the like. Depending rator I3 through a conduit I9. The liquid re- U-shaped refrigerant circulating passages 25 exfrigerant is vaporized by the absorption of heat tend downwardly from the header 20 within the from the chamber II and the vapor collects in side wall 29 and across the bottom wall 32, and 55 the sinuous conduit 26 extends in part across the top wall 3| and in part within the side wall 30.

The sheets 22 and 23 are secured together around their edges and between the indentations by welding, brazing or any other suitable manner; the front and rear edges of the sheet 22 being folded over the respective edges of the sheet 23 in the manner indicated at 24. A flange 33 formed on the sheet 22 at the end thereof remote from the header 20 fits against the side wall 29 and is welded or otherwise secured thereto. A metal sheet 34 is welded to the upper end of the side wall 30 and constitutes a side wall for an upper freezing chamber. The wall 29 and the wall 3l are provided with flanges 35 and 36 respectively, for securing the evaporator to a removable top wall of a refrigerator cabinet. The ,general arrangement of the header and the passages within the wall of the evaporator is not my invention but is the invention of Leonard W. Atchison, and is disclosed and claimed in his copending application, Serial No. 51,846, led November 27, 1935, and assigned to General Electric Company, the assignee of my present invention, I do not, therefore, herein claim any invention claimed in the said Atchison application.

Referring now to Figs. 2 and 3, liquid refrigerant is admitted to the evaporator I3 through the conduit I9 and enters a passage 31 formed in the side wall 29 and the bottom wall 32. 'Ihe passage 31 communicates directly with the sinuous passage 26 and the refrigerant therefore flows into the sinuous passage, circulates therethrough and ows to the manifold 21.

The ducts 28 which convey the refrigerant uniformly from the manifold 21 to the several U-shaped passages 25 are arranged .in such manner as to induce a positive circulation of liquid refrigerant in a predetermined direction through each of the U-shaped passages. In order to accomplish this mode of circulation each of the ducts 28 is arranged to inject refrigerant directly and longitudinally into one leg of a U-shaped passage, to produce a flow through that leg of the passage and upwardly to the header 20. 'I'he resultant injector action produces a positive flow of liquid refrigerant through each of the U-shaped passages, liquid refrigerant recirculating from the header downwardly through the other leg of the passage; a rapid circulation and recirculation in all U-shaped passages is thereby provided. In order to minimize the turbulence of the liquid refrigerant within the header 20 which results from the rapid circulation of refrigerant, I arrange the injectors 28 so that the same direction of flow of liquid refrigerant obtains in adjacent legs of adjacent U-shaped conduits. It is evident that when the refrigerant is thus caused to circulate in the same direction in the pairs of adjacent legs of the U-shaped passages, there will be a less frequent reversal of the direction of flow of refrigerant along the header. If the direction of flow were made thev same in al1 the U-shaped passages, each passage would have refrigerant flowing therein in a direction opposite the direction of flow in the adjacent passage and there would be increased turbulence and consequently increased resistance to the circulation of liquid refrigerant. In the evaporator, as described above, there will be larger areas of upward and downward flow, since each, area will correspond to the portion of the header above two of the legs of the U-shaped passages.

Dun'ng the operation of the evaporator described above, refrigerant is admitted to the passage 31 from the passage I9 and ows from the in the chamber Il and from articles placed on the freezing shelf 31a; The vaporized and liquid refrigerant flows fromf the manifold 21 in substantially equal amounts through the ducts 23 and into the several U-shaped passages 25. Since each of the ducts 28 directs refrigerant upwardly into only one leg of the U-shaped passage with which it communicates, the direction of flow of refrigerant in each U-shaped passage is definitely predetermined and minimum turbulence of liquid -refrigerant in the header is assured at all times. Liquid refrigerant vaporized within the passages 25 by the absorption of heat from articles resting on the shelf 32a and from the air within the chamber Il, collects in the header and is withdrawn therefrom through suction conduit 2l.

It will be apparent from the foregoing that I have provided a flooded evaporator of simple construction having an improved arrangement for predetermining the direction of ow of refrigerant in the circulating passages thereof and for assuring a minimum of turbulence and, therefore, a minimum resistance to circulation of the liquid refrigerant.

While I have described my invention in connection with a household refrigerator, other applications will readily be apparent to those skilled in the art. Ido not, therefore, desire my invention to be limited to the particular construction shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A flooded evaporator for refrigerating machines comprising a header and a plurality of separate depending U-shaped refrigerant circulating passages, both of the ends of each of said passages communicating with said header and all of the ends of said passages being substantially in longitudinal alinement along said header, means including a plurality of ducts one communicating with the lower portion of each of said U-shaped passages and injecting liquid refrigerant longitudinally into said U-shaped passages for producing a circulation of liquid refrigerant toward said header in one leg of each of said passages and away from said header in the other leg of each of said passages and for determining the direction of circulation of liquid refrigerant in each of said passages, and means for withdrawing gaseous refrigerant from said header.

2. A flooded evaporator for refrigerating machines comprising a header and a plurality of separate depending U-shaped refrigerant circulating passages, both of the ends of each of said U-shaped passages communicating with said header and all of the ends of said U-shaped passages being substantially in longitudinal alinement along said header, means including a plurality of ducts of relatively small cross-sectional area as compared with the cross-sectional area of said passages and injecting liquid refrigerant longitudinally into one leg of each of said passages for producing a circulation of liquid refrigerant toward said header through said one leg and away from said header in the other of said legs, and means for withdrawing gaseous refrigerant from said header.

3. A flooded evaporator for refrigerating machines comprising a header and a plurality of separate depending U-shaped refrigerant circulating passages, both of the ends of each of said passages communicating with said header and all of the ends of said passages being substantially in longitudinal alinement along said header, means communicating with the lower portion of each of said U-shaped passages and injecting liquid refrigerant longitudinally into said U-shaped passages for producing a circulation of liquid refrigerant toward said header in one of the legs of each of said passages and away from said header in the other leg of each of said passages and for determining the direction of circulation of liquid refrigerant in each of said passages, said circulation producing means being arranged to circulate the liquid refrigerant in the same direction in adjacent legs of adjacent ones of said U-shaped passages,

and means for withdrawing gaseous refrigerant 10 from said header.

CHRIS'I'IAN S'I'EENS'I'RUP.

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