US2512748A - Expansion joint for heat exchangers - Google Patents

Description

June 27, 1950 c. E. LUCKE EXPANSIONJOINT FOR HEAT EXCHANGERS Filed Feb. 12, 1945 INVENTOR ATTORNEY.

Patented June 27, 1950 2,512,748 EXPANSION JOINT FOR HEAT EXCHANGEBS Charles E. Lucke, New York, N. Y., assignor to Worthington Pump and Machinery Corporation, Harrison, N. J a-corporation of Delaware Application February 12, 1945, Serial No. 577,413

4 Claims. (Cl. 257-236) The present invention relates to heat exchangers or surface condensers, and more particularly to the shell and tube type of construction in which there is a bundle or bank of straight tubes between two tube sheets in the shell, at least one tube sheet being fixed to the shell, such that the shell and the tube bundle do not expand equally and, therefore, require an expansion joint'in the shell if both tube sheets are fixed to the shell, or between the free tube sheet and the shell if only one tube sheet is fastened to the shell in order to compensate for relative expansion of the tubes and the shell. Shell expansion joints heretofore devised are often ineffective, too stiff or too weak, and always expensive. For freedom of expansion of the tube bundle in the shell, such devices as floating heads, packed shells, stuffing boxes and the like have been in use, but all are expensive and not entirely satisfactory in service.

Accordingly, an object of the present invention is to provide a heat exchanger wherein a relatively inexpensive and highly efficient expansion joint is provided'to accommodate relative expansion between the tubes and the containing shell and to maintain fluid-tight joints between the relatively movable parts. More specifically, the present invention embodies a rubber ring which is bonded to the edge of the free tube sheet, and either held tightly to the shell by squeezing, or bonded to a metal member so held, or bonded directly to the shell. The rubber and its fastening are such as will stress the rubber preferably in shear by relative movement of the sheet and the shell, or cause the rubber to flex, or stretch in tension, it being understood that rubber is substantially non-compressible. The expansion joint is also so designed that bonding of the rubber may be omitted in one embodiment thereof.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing an expansion joint for heat exchangers of a preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawings:

Figure 1 is a. fragmentary sectional view of a heat exchanger in accordance with the present invention.

Figure 2 is an enlarged sectional detail view of a portion of the expansion joint illustrated in Figure 1.

Figure 3 is a view similar to Figure 2 but illustrating an expansion joint embodying differences in details of construction.v

Figure 4 is a view similar to Figure 2 but illustrating other-differences in mechanical detail.

Figure 5 is a view similar to Figure 2 but illustrating other changes in the details of construction.

Figure 6 is also a view similar to Figure 2 but illustrating further changes in mechanical detail.

Referring more particularly to the drawings, Figure 1 illustrates a portion of a heat exchanger which embodies a shell I having flanges ll welded to its ends. While the condenser structure of Figure 1 illustrates one tube sheet I 2on'ly, the construction will, of course, incorporate two tube sheets in the usual manner. The tube sheet shown is of the floating type, while the other tube sheet may be fixedly anchored to the shell structure. Such anchorage may be obtained by clamping the tube sheet between one of the flanges II and a bonnet or cover l3, bolts ll being provided for clamping the tube sheet firmly in such a position.

Within the shell in is mounted a bundle or bank of conventional tubes IS, the ends of which tubes are expanded into both tube sheets, only one of which is herein illustrated, as at l2. An annular rubber body I6 is mounted between the tube sheet l2 and a metallic ring ll, the latter having a flange l8 interposed between the second flange II and a, bonnet or cover IS, the latter being attached to the flange H by bolts 20.

The rubber body It includes a groove 2| in its inside wall face, which groove receives the peripheral margin of the tube sheet l2, and this margin is bonded to the body IS in accordance with well known methods of bonding material such as rubber to metal. The ring I! includes a flange 22 which is arranged concentrically of the tube sheet I2 and the body l6, which flange includes circumferentially extending ribs 23 which co-act with the flange 22 to provide a channel 24 within which is housed the outer edge margin of the body It, which margin is bonded to the flange 22 and the ribs 23.

Figures 1 and 2 illustrate an expansion joint wherein the construction is such as to utilize the rubber in shear. Such a construction provides a highly efllcient expansion joint for accommodating relative expansion of the tubes and the shell, 9. joint which remains fluid-tight to prevent contamination of one liquid by another.

Figure 3 illustrates diiferent details of construction wherein the rubber body 25 is substantially identical with that shown in Figure 2, in that a theedgemarginofthetubesheetllislodzcd inthegrooveflinthebodyflandbonded thereto. The tubes II are expanded in the tube sheet 28, the difference in construction residing in the fact that the rubber body 25 is located between the shell nange 2! and the bonnet or cover ll. Thus the outer edge margin of the body II is clamped firmly in the position shown through tightening of the bolts II. The construction of Figure 3 also utilizes the rubber in shear and eliminates the ring structure such as that shown at II in Figure 2, in addition to remaining fluidtight in the same degree as the structure of Figures 1 and 2. To prevent excessive compression and distortion of the body 2| when the bolts ii are tightened, a spacing ring 3| is placed between the flange 29 and the cover ll.

In Figure l, the tube sheet 32 is also of the floating type and carries the tubes 33, the latter being expanded in the sheet. To the peripheral face 34 of the tube sheet 32 is secured an outwardly opening channel 15, as by welds 3'. A similar channel 31 is fixedly secured to the heat exchanger shell structure, as by a flange 38 which is located between the condenser shell flange 39 and the hood or cover 40, flange ll being made secure through tightening of the bolts ll. Between the channels 35 and 31 is arranged an annular rubber body 41, which body is bonded to both flanges or rings 35 and 31. Accordingly, the expansion joint of Figure 4 is identical with the forms of Figures 2 and 3 so far as utilization of the rubber in shear and the provision of a fluidtight joint are concerned.

The construction of Figure illustrates a tube sheet 43 which is of such diameter as to extend laterally beyond the heat exchanger shell 44. Tubes It are expanded in the tube sheet 43. To the shell 44 is welded a flange II, and the bonnet or cover 41 is flxedly secured to the flange 48 by bolts ll. The flange l6 and the cover 41 are of such diameters as to provide parallel faces 49 which are of such diameters as to lie outside the shell .4, with the edge margins of the tube sheet 43 lying between the faces 49. Between the face 49 of the flange 46 and the tube sheet 43 is arranged a rubber ring 50 which may be circular in cross section. A similar rubber ring 5| is interposed between the tube sheet #3 and the face 48 on the cover 41. Both rubber rings 50 and SI are bonded to the tube sheet 43, as indicated at 52, although this is not of critical importance, and the rubber rings may also be bonded to the shell and the cover to provide greater protection against leakage. When installed, the rubber rings 50 and II are placed under the necessary degree of initial compression, so that the cross sectional contours are flexed from round in the manner shown. A spacing ring 52' is placed between the flange l6 and the cover 41 to prevent excessive compression and distortion of the rubber rings when the bolts ll are tightened. The shell 44 extends a short distance beyond the face 49 on the flange it, while the cover It is provided with a flange 53 which is similarly arranged with respect to the face 4! on that cover. Accordingly. the rubber bodies or rings III and SI are confined in metal pockets ll and BI, respectively, which are of larger volumes than the contained rubber rings, since the pockets are of greater dimensions in radial directions.

In the construction of Figure 6, a rubber body or ring II of tubular contour is bonded to the peripheral face of the tube sheet 58, the latter with the zones of bond so spaced as to provide an unbonded length between the end of the shell and the tube sheet.

In a construction such as that shown in Figure 6, the construction is such as to utilize the rubber ring 51 in tension or in flexure. In operation, any movement of the tube sheet away from the shell I places the rubber ring 81 in tension, while .mcvement in the opposite direction will flex the ring, as in the buckling of along column, but the expansion joint remains fluid-tight at all times. In the structure shown, the bonnet or cover I! is bolted at 63 to the flange N, and the cover '2 is of such inside diameter as to provide freedom for the ring 81 and the tube sheet 50. A spacing ring it between the flange i0 and the cover 82. prevents excessive distortion of the rubber il when the bolts 03 are tightened.

The term rubber as herein employed includes both natural rubber and equivalent materials of the synthetic class, the latter being preferable in many cases because of its resistance to higher temperatures than natural rubber and to deterioration by certain liquids, such as oils. Different operating conditions may require rubber of different properties, and the rubber used in the expansion joint is selected on that basis. The term surface adhesion as employed in the claims is intended to include all methods by which rubber may be bonded to metals. It particularly contemplates certain modernmethods in which the rubber is, in effect, welded to the metal.

It will be understood that the invention is not to be limited to the specific construction or arrangementof parts shown, but that they may be widely modified within the invention deflned by the claims.

What is claimed is:

1. In an expansion means for a heat exchanger having an elongated shell and a movable transverse tube sheet within the shell, a circumferential member inside of the shell, means removably connecting the member to the shell, a second circumferential member fixed to the outer periphery of the tube sheet, and a circumferential rubber body connected in fluid tight relationship to each of the members to provied a flexible fluid tight joint. within the shell, said rubber body having across sectional length which is at least as great as its cross sectional width whereby it will be stressed in shear through relative movement of said sheet and said shell with respect to each other.

2. In an expansion means for a heat exchanger having an elongated shell and a movable transverse tube sheet within the shell, a circumferential member inside of the shell lying in the plane of the sheet, said member having a concave surface facing the outer periphery of the sheet, means removably connecting the member to the shell, and a circumferential rubber body connected by surface adhesion to the concave surface and in fluid tight relationship to the outer periphery of the sheet, said rubber body having a length width ratio at least equal to 1 whereby having the tubes II expanded therein. The 13 it will be stressed in shear through relative moveto'each other.

3. In an expansion means for a heat exchanger having an elongatedshell and a movable transverse tube sheet within theshell, a circumferential member inside of shell lying. in the plane of the sheet, means removably connecting the member to the shell, a second circumferential member fixed to the outer periphery of the tube sheet, said members having opposing concave surfaces, and a circumferential rubber body connected by surface adhesion to the concave surfaces to provide a flexible fluid tight joint within the shell, said rubber body having a cross sectional length which is at least as great as its cross sectional width whereby it will be stressed in shear through relative movement of said sheet and said shell with respect to each other.

4. In an expansion means for a heat exchanger having an elongated shell and a movable transverse sheet within the shell, a closure member for engagement with said elongated shell, a first channel having a flange secured between said elongated shell and said closure member, a second channel connected to the outer periphery of said transverse sheet, means providing a yleldable fluid tight joint between the shell and sheet comprising alrubber member connected by surface adhesion to the-second channel and to the first channel, in cross section said' member having a ratio of length to width which-is at least equal to 1. whereby it will be stressed in shear through relative movement oisaid sheet and said shell with respect to each other,

CHARLES LUCKE.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,626,772 Worden May 3, 1927 1,660,163 Heaton Feb. 21, 1928 2,020,092 Allen Nov. 5, 1935 2,257,804 Lord Oct. 7, 1941 2,375,105 Hile May 1, 1945 2,397,069 Young Mar. 19, 1946 FOREIGN PATENTS Number Country Date 516,002 Great Britain Dec'. 20, 1939 553,589 Great Britain May 27, 1943

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