US2009910A

US2009910A - Evaporator

Info

Publication number: US2009910A
Application number: US748960A
Authority: US
Inventors: Touborg Jens; Homer E Rosebrook
Original assignee: GIBSON ELECTRIC REFRIGERATOR
Current assignee: GIBSON ELECTRIC REFRIGERATOR; GIBSON ELECTRIC REFRIGERATOR Corp
Priority date: 1934-10-18
Filing date: 1934-10-18
Publication date: 1935-07-30
Anticipated expiration: 1952-07-30

Description

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Patented July 30, 1935 UNITED STATES PATENT orrlc's EVAPORATOB Application October 18, 1934, Serial No. 748,960 7 Claims. (Cl. 62-126) This invention relates to improvements in evaporators and, more especially, an evaporator for use in refrigerating apparatus.

The invention is particularly applicable to refrigerating apparatus in which lubricating oil is mixed with the refrigerant. This is more or less common practice in many types of refrigerating apparatus. When oil is thus used, however, difficulty has been encountered in some evaporators 1o heretofore used because of the formation of an oil film on the liquid refrigerant which hindered or lessened evaporation or boiling of such refrigerant. In our improved evaporator, this objection is lessened or overcome.

Among the features of our invention is the provision of an evaporator that is simple in construction, cheap to manufacture and efllcient in operation.

Another feature of our invention is the provision of a plurality of boilers connected in series, with the refrigerant entering one boiler at the bottom and leaving at the top. In this construction, a tube connecting two boilers will carry a certain amount of refrigerant in a gaseous state and, also, a certain amount of liquid, namely, the amount of liquid to be evaporated in the following boiler or boilers. Consequently, the gas which bubbles up in a boiler has a tendency to break up or disturb any oil film on the surface of the liquid refrigerant that otherwise might form. In this manner, retardation of boiling or evaporation by oil film is prevented or lessened. This is especially true of the last boiler, which may contain more oil than the preceding boilers, particularly if the evaporators should happen to be charged with an amount of refrigerant not quite suflicient to raise the liquid level close enough to the end of the outlet tube. Therefore, the operation of this type of evaporator is 40 not as dependent on a correct charge of refrigerant as an ordinary single boiler type.

We have found that connection of the boilers in series creates substantially free boiling of refrigerant in all the boilers so connected. This 45 is due to the fact that in the first boiler, into which the liquid enters, the boiling will be unhindered by any oil film, due to the fact that the top of the liquid is continually skimmed off and goes into the second boiler. The boiling of liquid 50 in the second boiler is also substantially unhindered by oil film, due to the fact that the gas which is evaporated in the first boiler continuously breaks up the oil film by bubbling up through it. 1

In these forms of devices embodying the features of our invention shown in the accompanying drawings- Figure 1 is a top plan view; Fig. 2 is a view, partly in side elevation and partly in section; Fig. 3 is an end view; Figs. 4, 5 and 6 are views similar to Figs. 1, 2 and 3, respectively, showing a modified form; Figs. 7, 8 and 9 are views similar to Figs. 1, 2 and 3, respectively, showing another modification; Fig. 10 is a view, partly in front elevation and partly in section, showing another modification; Fig. 11 is a. bottom plan view of the same; Fig. 12 is a view of the same in side elevation; and Fig. 13 is a view taken as indicated by the line l3 of Fig. 11.

In each of the devices shown in Figs. 1 to 9, inclusive, the evaporator comprises, in general,

'a sheet of metal in a U-shape with two cylindrical boilers or tubes inside about half way up lying side by side in the same horizontal plane. The lower portion of the sheet metal forms a lower shelf for an ice tray, and the two boilers may receive another ice tray on top of them, thus forming an upper shelf for this purpose.

In the evaporator shown in Figs. 1, 2 and 3, the sheet metal I is generally bent into a U- shape, as shown in Fig. 3, with the upper edges of the sides bent outwardly, as indicated by II, II to form attaching flanges provided with suitable holes l2 to receive the bolts, screws, or the like, to attach the evaporator to any suitable support above it. Portions of the side walls of the device shown in Figs. 1, 2 and 3 are bent inwardly to form the two cylindrical boilers l3, l3 lying side by side. The ends of these boilers are closed by suitable convex heads l4, l4 suitably welded, brazed or otherwise fastened in place.

It will be seen that by this construction a single sheet of metal is used to form the entire U- shaped members and both boilers, with the exception of the heads. It is to be understood that where the bent edges of the sheet metal come together at the sides, as indicated by l in the drawings, the adjacent folded edges of the sheet metal are suitably soldered, brazed or welded.

The bottom portion I6 of the U-shaped member may form a bottom shelf for an ice tray 11, and another ice tray 18 may be placed on top of the two boilers, the latter thereby serving as an upper shelf for such tray.

is indicates an inlet pipe for the evaporator and where this enters the boiler l3, there may be provided a check valve 20, if desired. The inlet pipe enters the bottom of one end of the boiler l3. Refrigerant leaves the top of this boiler at the other end through the pipe 2| which enters the bottom of the boiler l3. Refrigerant leaves the evaporator through the pipe 22 at the top of the boiler i3 at the end opposite the pipe 2|. The outlet pipe 22 may be bent into lower and

upper loops

22 and 22, respectively, in order to give this pipe an opportunity to pick up a certain amount of heat from the cabinet, thereby applying superheat to the gaspassing through the tube so that the latter will not frost up or sweat where it leaves the cabinet.

In the evaporator shown in Figs. 4, 5 and 6, there is also a U-shaped member made of sheet metal H with the attaching flanges Ill provided with holes H2. The sides of this member, however, are not bent inwardly to form the cylinders, but separate cylinders H3 and H3 are employed. The bottom of the U-shaped member is indicated by HG, which may serve as a shelf for an ice tray (not shown) and another ice tray (not shown) may be supported on top of the boilers H3 and H3. The ends of 'the two boilers, as shown in Fig. 9.

the boilers are closed by suitable heads Ill.

The side walls of the U-shaped member are convexly curved where they lie next to the boilers, as indicated by I It, to give good heat exchange contact with said boilers. This curvature, for example, may be carried for substantially 90 around the circumference of each boiler, and at the ends of the curved portions, the

sheet metal may be welded or brazed to the boilers, as indicated by H5.

The evaporator shown in Figs. 4, and 6 is provided with inlet, outlet and connecting tubes in the same manner as the evaporator of Figs. 1, 2 and 3, said tubes being indicated by the same reference numerals, augmented by 100.

The evaporator shown in Figs. 7, 8 and 9 is generally similar to the others above described, except for the method of forming the boilers. Here, again, there is a U-shaped member formed of sheet metal 2m with attaching flanges 2 provided with the holes 2|2. In this construction, two pieces of sheet metal are employed, an upper piecej'with its bottom carried entirely across to form the upper halves of the boilers 2 l3 and 2"". A separate piece of sheet metal is employed to form the bottom shelf 2 l6 and the lower halves of As here shown, the boilers are not provided with separate heads, but the ends are closed by drawing down the sheet metal to bring the edges together, as indicated by 2 (see Fig. 8). Where the edges join at the ends and also at the sides of the boilers and in the middle between the two boilers, the adjacent edges or faces of metal are suitably welded or otherwise fastened, as indicated by 215.

The evaporator of Figs. '7, 8 and 9 is here shown as provided with an inlet pipe 220 which enters one boiler at one end near the bottom. This boiler is connected at its other end near the top by a pipe 22l with the adjacent end of the adjoining boiler at the bottom, and the latter is provided with an outlet pipe 222 at the other end at the top.

In the evaporator shown in Figs. 10 to 13, inclusive, there is provided a single flat shelf instead of a U-shaped member. This shelf is made of sheet metal and under it are located four horizontally-arranged boilers side by side in the same horizontal plane. The sheet metal shelf we have indicated by 3M and the boilers by M3, M3, 2H3 and 3l3 The side edges of the shelf 3 I 0 are bent downwardly to form attaching flanges 3i I provided with the slots 3|2to hook over suitable fastening devices (not shown). Where the shelf 3! rests on top of the boilers, it is provided with convexly curved portions 3 l 0 contacting with the boilers through substantially 90 to give good heat' exchange relation between the sheet metal piece 3 0 and the boilers. The edges of the curved portions may be welded, soldered or brazed to the boilers, as indicated by M5.

In the evaporator of Figs. 10 to 13, inclusive, 3 I 9 indicates the inlet pipe and 320, an expansion valve. The refrigerant enters the boiler M3 at one end at the bottom, leaving at the opposite end at the top through the pipe 32l which enters the adjacent end of the next boiler at the bottom.

The refrigerant leaves the opposite end of this boiler at the top through the pipe 322, entering the next boiler at the bottom. .In the same way, the refrigerant leaves the boiler 3| 3 at the top through the pipe 323, entering the last boiler 3l3 at the bottom. 324 indicates the outlet pipe from the evaporator which leaves the last boiler 313 at the top at the end opposite where the pipe 323 enters.

It will be seen that there are several features common to all the forms of evaporator shown. For example, the use of a plurality of cylindrical boilers arranged side by side parallel to each other in the same horizontal plane connected in series with the refrigerant entering one boiler at the top at one end and leaving at the bottom of the opposite end. Also, the use of boilers and a piece of sheet metal in good heat exchange relation to the same to assist conduction of heat from the space being cooled to the boilers.

The evaporators shown in Figs. 1 to 9, inclusive, are similar in the sense that in each case there is a substantially U-shaped member made of sheet metal with two cylindrical boilers inside about midway between the top and bottom. In the three forms shown in these figures, however, different methods are employed in the formation of the boilers. In the evaporators of Figs. 1 to 3 and Figs. 7 to 9, the sheet metal which forms the U- shaped member is also used to form the side walls of the boilers. In the device of Figs. 4 to 6, separate tubes are employed to form the boilers and the sides of the U-shaped member are curved to contact the sides of these boilers.

It will be seen that in each of the evaporators shown in Figs. 1 to 13, inclusive, the sheet metal has curved portions adjacent the cylindrical boilers in order to give good heat exchange relation therewith. This heat exchange relation is accomplished in diflferent ways in the different forms, but the result is the same in each. In the evaporators of Figs. 4 to 6 and Figs. 10 to 13, the boilers are formed of separate tubes, but the sheet metal has curved portions closely contacting the walls of said tubes. In the other devices, the sheet metal itself is curved to form the walls of the boilers.

While we have shown and described certain embodiments of our invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims, in which it is our intention to claim all novelty inherent in our invention as broadly as permissible, in view of the prior art.

What we claim as new, and desire to secure by Letters Patent, is:

1. An evaporator including a plurality of cylindrical boilers and a piece of sheet metal having curved portions adjacent said boilers and in contact therewith to give good heat exchange relation therewith.

2. An evaporator, including; a U-shaped piece of sheet metal; and a pair of horizontal boilers lying inside thereof connected in series.

3. An evaporator, including; a U-shaped piece of sheet metal; and a plurality of horizontal boilers lying inside thereof about half-way between the top and bottom.

4. An evaporator, including; a U-shaped piece of sheet metal; and a plurality of horizontal boilers lying inside thereof in the same plane about half-way between the top and bottom.

5. An evaporator, including; a U-shaped piece of sheet metal with portions of the sides thereof bent to form the walls of cylindrical boilers lying inside thereof about half-way between the top and bottom.

6. An evaporator, including; a U-shaped piece of sheet metal with portions of the sides thereof bent to form two horizontal boilers lying in the same plane inside of said U-shaped member about half-way between the top and bottom thereof.

'1. An evaporator, includinz; a plurality of horizontal boilers connected in series and lying in substantially the same horizontal plane; and a piece of sheet metal on top of said boilers and in good heat exchange relation therewith.

JENS TOUBORG. HOMER E. ROBEBROOK.