US2056920A - Heat exchanger for refrigerating systems - Google Patents

Description

C. B. DEMANN HEAT EXCHANGE FOR REFRIGERATING SYSTEMS Filed July 17, 1955 'INVENTOR/ 62:71am: 2., .DEMHIVN HIS ATTORNEYS.

Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE HEAT EXCHANGER FOR REFRIGERATING SYSTEMS Application July 1'1, 1935, Serial No. 31,876

/ 7 Claims.

This invention relates to heat exchangers and particularly to the bonding of a plurality of pipes or tubes to a header of such exchangers.

Heretofore, in the construction of water cooled condensers of refrigerating systems for example,

considerable difficulty has been experienced in securing the ends of water circulating pipes or tubes to a heavy metal header which serves as a closure for a container into which compressed refrigerant is deposited and adapted to be cooled and liquefied. This difficulty was occasioned by the fact that the thick metal header caused heat being applied thereto at the ends of a tube adapted to be bonded to the header, to be dissipated or carried away from the points or surfaces to be bonded together more rapidly than would cause fluid-tight bonding of the tube to the header. My invention is therefore directed to overcoming the difficulty heretofore encountered in the bonding of ends of tubes or pipes to a metal header.

An object of my invention is to provide an improved low cost heat exchanger construction.

Another object of my invention is to provide an improved constructionof a header for, a heat exchanger to which header a plurality of fluid conveying pipes or tubes are secured.

A further object of my invention is to provide a header of a heat exchanger with thin walled tube-attaching portions remote from the thick main body portion of the header so as to permit rapid and efiicient fluid-tight bonding of the ends of tubes to the header.

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

In the drawing:

Fig. l is a sectional view taken on the line ll of Fig. 2 through a heat exchanger of a refrigerating system shown diagrammatically connected with the exchanger;

Fig. 2 is an end elevational view of the heat exchanger; 1

- Fig. 3 is an enlarged fragmentary sectional view showing a portion of the heat exchanger constructed in accordance with the present invention; and

Fig. 4 is a view similar to Fig. 3 showing a modified construction.

Referring to the drawing, for the purpose of i1- lustrating my invention, I have shown diagrammatically in Fig. 1 thereof a closed refrigerating system including a heat exchanger or condenser generally designated by the reference character In. The condenser or heat exchanger I0 comprises. an elongated cup-shaped metal member ll having its open end closed by a relatively heavy or thick metal end plate or header I2 which is welded thereto. A plurality of substantially U- 5 shaped lengths of pipe or copper tubing l3 have their ends l4 secured to end plate or header l2 in a manner to be more fully described hereinafter. An outer plate I6 is secured to header I 2 by bolts or any other suitable securing means. 10 The outer plate I6 is provided with a plurality of hollowed-out portions l1 forming passages each of which interconnect one end of one of the U- shaped tubes I 3 with an end of another adjacent tube I3. The communication of passages I1 to- 15 gether with the arrangement of tubes I 3 provide a series path of flow for a fluid, such as water, to be circulated through the tubes l3 of condenser I0. The series path of flow through tubes I3 and passages ll includes an inlet connection l8 and an outlet connection l9 provided on the end plate IS. A plurality of fins 2| are secured to and extend transversely to tubes l3 for increasing the heat transfer surface thereof. A heavy plate 22 located near the yoke portions of the U tubes I3 25 has an extending portion or device 23 which rests against the inner wall of member H to support the tubes and fins therein. The elongated metal cup-shaped member ll forms a tank around the tubes l3 and this tank is provided with a fluid 30 inlet connection 25 and an outlet connection 26 adapted to be connected with a refrigerating system. A bafiie 21 located beneath the inlet connection 25 of the exchanger is provided with a plurality of small openings for distributing re- 35 frigerant circulated to the exchanger I 0 along the length of the tubes l3.

The refrigerating system includes in addition to the condenser H) a compressor 28, operatively connected through suitable belt and pulley .con- 40 nections 29, to an electric motor 3|. The compressor 28 upon being operated by motor 31 withdraws gasified or evaporated refrigerant, through pipe 32, from an evaporator or cooling element 33. The evaporated refrigerant is com.- 45 pressed and circulated under pressure, through pipe 34 and the inlet connection 25 on member ll, into the tank or heat exchanger I ll. Any suitable cooling fluid such as water is circulated from the inlet connection l8 through one of the 5 passages I! in plate l6 (see Fig. 2) to one of the tubes I3. As before stated the circulation of water through heat exchanger I0 is a series path of flow between the water inlet [8 and outlet l9 thereof. The circulation of water through the 55 exchanger therefore cools and causes condensation of the compressed refrigerant flowing through the openings in baflie 21 and distributed' over the length of tubes l3. Refrigerant thus liquefied accumulates or collects in the bottom of tank In and is stored therein until admitted to evaporator 33 through the pipe or conduit 36 under control of a suitable expansion device or valve 31. The motor 3| and consequently compressor 28 is intermittently operated by any suitable control switch 38 interposed in the electric power lines leading to motor 3|. Switch 38 is actuated by a bellows 39 connected, by a pipe 4|, to a thermostat bulb 42 located in thermal relation with the evaporator 33. It is to be understood that the bellows 39, pipe 4| and bulb 42 form a conventional and well-known thermostatic system containing a volatile refrigerant for controlling operation of the refrigerant circulating means.

Since my invention relates to the heat exchanger or condenser Ill and particularly to the construction of that portion of header l2 to which the tubes l3 are to be secured, I will now refer to Figs. 3 and 4 of the drawing for describing my improvement. It will be noted that the header l2 of condenser ||l (see Fig. 3) has tubular inserts 5|, preferably of copper material, brazed to the walls 53 of the tube receiving openings provided therein. The outer face of header I2 is counterbored as at 53 adjacent the walls 52 of the opening and the ends 54 of inserts 5|, adapted to receive the ends M of the U-shaped tubes |3, extend beyond the wall 52 into the space provided by the counterbore 53. The ends 54 of inserts 5| have a tapered inner surface 55 providing-a space between the outer wall of the tube 3 and the insert. The extension of the end 54 of insert 5| into the space provided by the counterbore 53 thus locates the portions of tube l3 and insert 5| to be bonded together remote from the main thick body portion of header l2 and thereby permits heating and bonding of the portions to be secured together with solder without danger of the heat being rapidly dissipated away from the points to be bonded by the body portion of header l2. Upon heating the end 54 of insert 5| and the end of the tube |3 solder will freely flow between same along the taper 55 and form a fluid-tight connection therebetween. The inserts 5| are brazed to header |2 prior to assembling the tubes |3 thereto and it is obvious that the construction permits rapid heating of the ends 54 of inserts 5| and the ends of the tubes |3 located therein to cause bonding together thereof at a point spaced from the main body portion of header I2.

"Tubes |3 may therefore be readily and quickly soldered to header l2 and the header together with the tubes l3 securedthereto may then-be inserted in the elongated cup-shaped member through the open end thereof. The header I2 is then brazed or welded to the walls of member II to form a closed tank. The end plate I6 is adapted to be bolted to header l2 so that the grooves or passages provided therein aiford communication between certain ends of tubes l3 to form a series path of flow for the cooling fluid to' be circulated through the closed tank heat exchanger or condenser Hi.

In Fig. 4 of the drawing I have shown a-modifled form of construction which permits the ends of the tubes l3 to be soldered or bonded directly to the metal header I2. In this form of the invention a flange 56, formed on header l2 by cutting a groove 51 inwardly from the face of the header, is tapered as at 58 for receiving solder to' be applied between the outer wall of tube l3 and flange 58. The end of tube l3 and the flange 56 in this modified form of con- 'struction can be readily heatedto a suflicient temperature to cause melting and flow of solder between the flange 55 and tube I3 for bonding the parts together since the points to be heated and bonded are remotely spaced from the main thick body portion of header l2.

It will be seen from the foregoing that I have provided an improved method or process of securing the ends of tubes or pipes to a heavy metal header. The improved construction insures that parts to be secured together can be heated to a soldering temperature without danger of heat being dissipated by the thick body portion of one of the metal parts from the points to be bonded together. My improvement greatly facilitates the manufacture and assembly of condensers or heat exchangers while at the same time reducing the cost of producing same.

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. A heat exchange structure comprising in combination, a plurality of substantially parallel tubes, a header having a plurality of openings therein for receiving the ends of said tubes, flange means extending parallel with and laterally from the walls of said tube-receiving openings and forming one wall of a hollowed-out portion provided in the face of said header adjacent said tube-receiving openings, and said tubes extending parallel with said flange means and having their ends terminating adjacent the outer ends of the flange means and below the face of said header to thereby provide a joint located remote from the main body portion of said header adapted to be heated to cause bonding of the tubes to said header.

2. A heat' exchange structure comprising in combination, a plurality of substantially parallel tubes, a header having a plurality of openings therein for receiving the ends of said tubes, flange means extending parallel with and laterally from the walls of said tube-receiving openings and forming one wall of a hollowed-out portion provided in the face of said header adjacent said tube-receiving openings, and said tubes extending parallel with said flange means and having their ends terminating adjacent the outer ends of the flange means and below the face of said header to thereby provide a joint located remote from the main body portion of said header adapted to be heated to cause bonding of the tubes to said header, said flangemeans having its surface adjacent the outer wall of a tube tapered to provide a space between the wall of the I tube and said flange for the reception of a bonding material.

3. A heat exchange structure comprising in combination, a plurality of substantially parallel tubes having a plurality of flns extending transversely thereto, a header having a plurality of openings therein, said headerhaving its face counterbored adjacent each of said openings, a tubular insert secured in each of said openings, said inserts adapted to receivesaid tubes and having their ends extending from the walls of said openings into the space provided by said counterbores to form a wall of a groove surrounding the ends of said inserts, each of said tubes having its end terminating adjacent the end of its cooperating insert, and the ends of said tubes and said inserts being disposed below the face of 'said header and providing surfaces remote from the main body portion of said header to be heated and bonded together.

4. A heat exchange structure comprising in combination, a plurality of substantially parallel tubes having a plurality of fins extending transversely thereto, a header having a plurality of openings therein, said header havingits face counterbored adjacent each of said openings, a tubular insert secured in each of said openings, said inserts adapted to receive said tubes and having their ends extending from the walls of said openings into the space provided by said counterbores to form a wall of a groove surrounding the ends of said inserts, each of said tubes having its end terminating adjacent the end of its cooperating insert, the ends of said tubes and said inserts being disposed below the faceof said header and providing surfaces remotefrom the main body portion of said header to be heated and bonded together, and said inserts having their surface adjacent the outer wall of said tubes tapered to provide a space between the wall of the tubes and said inserts for the reception of a bonding material.

5. A heat exchange structure comprising in combination, a plurality of tubes, a header having a plurality of openings therein for receiving the ends of said tubes, flange means extending parallel with and laterally from the walls of said tube receiving openings and forming one wall of a hollowed-out portion provided in the face of said header adjacent said tube receiving openings, at least a portion of said tubes extending parallel with said flange means and having their ends terminating adjacent the outer ends of the flange means and below the face of said header to thereby provide a joint located remote from the main body portion of said header adapted to be heated to cause bonding of the tubes to said header, and a closure member for said heat exchange structure adapted to be clamped upon the face of said header, said closure member having passages formed therein providing comunication between certain of said plurality of tubes.

6. A heat exchange structure comprising in combination, a plurality of tubes, a header having a plurality of openings therein for receiving the ends of said tubes, flange means extending parallel with and laterally from the walls of said tube receiving openings and forming one wall of a hollowed-out portion provided in the face of said header adjacent said tube receiving openings, at least a portion of said tubes extending parallel with said flange means and having their ends terminating adjacent the outer ends of the flange means and below the face of said header to thereby provide a joint located remote from the main body portion of said header adapted to be heated to cause bonding of the tubes to said header, said flange means having its surface adjacent the outer wall of a tube tapered to provide a space'between the wall of the tube and said flange for the reception of a bonding material, and a closure member for said heat exchange structure adapted to be clamped upon the face of said header, said closure member having passages formed therein providing communication between certain of said plurality of tubes.

7. A heat exchange structure including a conduit and an end plate having an opening in its main body portion receiving the conduit, flange means extending from the wall of said conduitreceiving opening of said end plate and terminating inwardly of one face of said end' plate, said flange means having its inner wall diverging laterally from the wall of the conduit-receiving opening in a direction toward said one face of said end plate, said flange means forming a wall of a hollowed-out portion provided in said one face of said end plate adjacent said conduit-receiving opening, and said conduit extending along said flange means and having its end terminating adjacent the outer end of the flange means and below said one face of said end plate to thereby provide a joint located remote from the main body conduit-receiving portion of said end plate adapted to be heated to cause bonding of the

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