US2166808A - Surface cooler - Google Patents

Description

Jul 18, 1939. A. o. FLINDT 2,166,808

SURFACE COOLER Filed Sept. 1, 1938 Inventor Albert: C). Flincit,

byH MM! is Att. car-n ey.

Patented July 18, 1939 PATENT OFFICE SURFACE COOLER Albert 0. Flindt, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application September 8 Claims.

My invention relates to surface coolers, and more particularly to that type surface cooler used with electrical apparatus or dynamo-electric machines.

In surface coolers, the cooling medium usually is passed between suitable headers through a plurality of finned tubes supported by tube plates in the headers and by supports arranged intermediate the end headers, and the medium to be cooled or condensed is passed over the outside of the tubes within the cooling chamber. After the medium has been cooled or condensed. it is collected and employed as desired. In ships or other installations employing impure or salt water as a cooling medium, it is very important that the medium which is cooled or condensed in the surface cooler does not come in contact .with the cooling medium, as the latter would contaminate the medium which is cooled or condensed. In actual practice it has been found that it is diflicult to prevent this condition, as often one or more of the joints in the cooler between the tubes and the tube plates in the headers become loose and the medium leaks into the enclosing chamber containing the medium to be cooled. Furthermore, the tubes themselves often develop leaks due to corrosion, and the vibration sometimes found in such installations has a tendency to wear away the heat transfer finned elements and the tube where they pass through the supports.

An object of my invention is to provide an improved surface cooler construction which will dampen the vibration of the tubes and reduce wear between the tubes and the supports to aid in preventing contact between the cooling medium and the medium tobe cooled.

Another object of my invention is to provide an improved vibration damping or fin cushion element.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanyingdrawing, and the features of novelty which characterize my invention will be pointed out more particularly in the claims appended to and forming a part of this specification.

In the drawing, Fig. 1 is a side elevation of a surface cooler embodying my invention with the ductwork removed; Fig. 2 is a fragmentary sectional view through one of the intermediate supports showing the arrangement of a finned tube in the support provided with one of my improved vibration damping elements; Fig. 3 is a 1, 1938, Serial No. 227,901

fragmentary perspective view of an embodiment of the damping element shown in Fig. 2; Fig. 1 is aperspective view of another embodiment of the damping element shown in Fig. 2; Fig. 5 is a perspective view partly broken away showing 5 another embodiment of my improved damping element; and Fig. 6 is a fragmentary sectional side elevation of the damping element shown in Fig. 5 applied to a finned tube.

Referring to the drawing, in Fig. 1 I have 10 shown a surface cooler comprising two spacedapart headers I0 and II communicating with each other through a plurality of tubes II. The headers i0 and l I are rigidly held in spaced-apart relation by two substantially parallel casing sheets 15 i3 provided with flanged ends ll secured by bolts I5 to the headers ID. The sheets ll form opposite side walls of a chamber l6 which encloses the tubes i2 and are provided with suitable connections for passing a medium to be cooled 20 through the chamber Ii in contact with the tubes if. The outer surface of each of the tubes i2 is provided with suitable outwardly extending heat transfer surfaces comprising a spiralled fin element i'l secured in good heat exchange reia- 25 tionship with the tubes II, as by welding, soldering, brazing, or the like. Heat is absorbed from the medium to be cooled in the chamber It by the finned elements I! and is readily transferred to the cooling tubes l2 and into the cooling water 30 passing therethrough, which carries away the heat from the surface cooler. In order to provide a more rigid structure and to prevent sagging c of the cooling tubes ii, a plurality of supports comprising transversely extending plates it are 35 arranged in the chamber l6 intermediate the end headers ill and II. These supporting plates II are secured in any suitable manner to the side walls of the chamber l6 and are provided with a plurality of openings it through which the cool- 40 ing tubes and the spiralled fin heat exchange elements extend. During normal operation the fins l1 rest in contact with the bottom of the openings I! in the supporting sheets l8, thus dividing the distance between the tube sheets at the end 5 headers into a number of spans to prevent excessive deflection of the tubes I2. As has been stated before, in ships or-similar installations these surface coolers are often subject to vibrations which may become quite destructive if sup- 50 porting or spacing plates, such as the plates II, are not provided so as to retain the cooling tubes in their proper spaced-apart relationship. It has been found, however, that these supporting or spacing plates ll tend to wear away the fin heat exchange elements I7, and even have been found to produce holes in the sides of the cooling tubes l2 due to excessive rubbing between the supporting or spacing plates I8 and the tube elements. Such wear of the tubes l2 results in the undesirable contamination of the medium to be cooled with the cooling medium, and this is particularly undesirable when the medium to be cooled is used in ventilating or cooling electrical apparatus. In

order to dampen vibrations and cushion the contact between the tube elements and the plates I8, I provide a vibration cushioning element 20 formed of a resilient, deformable, rubbery material, such as resilient rubber, which I arrange between adjacent sides of the heat transfer surfaces of the fin element I! about the tube l2 and within the opening IS in the plates l8. As is shown in Fig. 2, this resilient element is readily secured or clamped in position between the heat exchange surfaces by bending over the outer edges 2| of the fin element l'l adjacent the outer edges at each end of the damping element. This damping element may be conveniently formed .of a strip of resilient rubber, as shown in Fig. 3,

which is of substantially uniform width and substantially uniform radial depth. When this type damping element is used, an end of the strip 20 is clamped by bending over the outer edge 2| of the fin element l1, and it is then wound spirally between adjacent convolutions of the spiral fin I! to a thickness axially of the tube l2 slightly greater than the width of the supporting plate l8. The outer end of the rubber strip 20 is then also clamped in position by bending over the outer edge 2| of the spiral fin II. In this manner the resilient damping or cushion element is securely held in position on the tube l2. This cushion element is arranged to extend radially substantially to the outer edge of the fin elements, although it may not extend completely to this outer edge when first applied to the tube as shown in Fig. 2. jected to vibrations which produce wearing of the fins by contact between the fins and the supporting plate, the resilient cushion 20 will come in contact with the supporting plate and provide a resilient cushioning support between the plate I! and the tube l2 which greatly lessens the wear of the fins and lengthens the life of the tube elements.

In Fig. 4 I have shown another embodiment of a vibration damping or fin cushion element of a resilient rubbery material which is formed as a spiral 22 of substantiaL uniform radial depth. The outwardly extending sides 23 'of this spiral element 22 are tapered inwardly to provide a greater width at the outer edge 24 than at the inner edge 25. This provides a better gripping surface between the fin packing and the adjacent sides of the fin element IT, as the compression of the rubber adjacent the outer edge of the packing tends to prevent any displacement which might occur between the packing and the sides of the fin. Fur'thernore, since the width of this element varies from the inner to the outer,

edge thereof, it may be used with tubes having slightly different axial spacings between adjacent convolutions of the spiral fin element H.

In some instances it may be found desirable to provide this vibration damping or fin cushion element in the form of a split tubular bushing 26 such as shown in Figs. 5 and 6. In this tubulararrangement, the outer surface is cylindrical in form and is formed with a spiral groove 21 on the inner side thereof. This bushing or cushion If the tube is subis split longitudinally at 28 to facilitate arranging it about the finned tube. As shown in Fig. 6, the sides of the groove 21 extend about the sides of the finned tube, and the outer cylindrical edge of the packing extends over the outer edge of the fin l'l, thereby providing a resilient support for the tube within the opening IQ of the supporting plate l8. The packing or vibration damping elements shown in Figs. 4, 5, and 6 may be molded in any convenient length and then cut to the desired length, depending upon the width of the supporting plates l8.

While I have described and illustrated particular embodiments of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangements disclosed, and I intend in the appended claims to cover all modifications which do not depart from 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 surface cooler including a support having an opening therein, a tube having a plurality of outwardly extending adjacent heat transfer surfaces, said tube and said surfaces extending through said support opening, and resilient means arranged between adjacent sides of said heat transfer surfaces extending substantially to the outer edge thereof and arranged in said support opening.

2. A surface cooler including a support having an opening therein, a tube having a plurality of outwardly extending adjacent heat transfer sursurfaces, said tube and said surfaces extending through said support opening, and means including a substantially uniform strip of resilient material coiled between adjacent sides of said heat transfer surfaces extending substantially to the outer edge thereof in said support opening.

4. A surface cooler including a support having an opening therein, a tube having a spiralled outwardly extending heat transfer element providing a plurality of adjacent heat transfer surfaces, said 'tube and said spiralled element extending through said support opening, and a spiral coil of resilient material arranged between adjacent sides of said heat transfer element extending substantially to the outer edge thereof in said support opening, said resilient coil being of substantially uniform depth and having a tapered side providing a relatively greater width at the outer edge than at the inner edge thereof.

5. A surface cooler including a support having an openingtherein, a tube having a spiralled outwardly extending heat transfer element providing a plurality of adjacent heat transfer surfaces, said tube and said spiralled element extending through said support opening, and a tubular element of resilient material having a spiral groove formed in the inner side thereof and arranged about said heat transfer element, the outer surface of said tubular element extending over the outer edge of said heat transfer element and providing a resilient support therefor.

6. A surface cooler including a support having an opening therein, a tube having a spiralled outwardly extending heat transfer element providing a plurality of adjacent heat transfer surfaces, said tube and said spiralled element extending through said support opening, and a tubular element of resilient material having a groove formed in the inner side thereof and arranged about said heat transfer surfaces and extending between adjacent sides thereof in said support opening, the outer edge of said tubular element extending over the outer edge of said heat transfer element and providing a resilient support therefor.

form radial depth and a spiral groove formed-in the inner side thereof.

ALBERT O. FLINDT.

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