US1756458A - Tube sheet - Google Patents

Description

April 29, 1930. c. w. GORDON TUBE SHEET Filed Jan. 4. 1929 1 N V EN TOR. C//z 5 14. a 'a n.

A TTORNE Y.

Patented Apr. 29, 1 930 UNITED, STATES PAT Nr *OFFICE CHARLES WQGORDON, OF PLEASANTVILJE, YORK, ASSIGNOR TO THE HEATEB COMPANY.

TUBE

or NEW YORK, N. a'. 4

samir Application filed January 4, 1929. Serial No. 330,179.

tion is equally well applicable to other types of apparatus.

Fig. 1 is generally a vertical longitudinal section through a locomotive type feed water heater, the right half being a true section, the left half showing the shell in section and the parts within the shell partly in elevation and partly in central-vertical section; Fig. 2 is an end elevation looking from the right of Fig. l; and Figs. 3 and 4 are plan and elevational views respectively of the improved form of tube sheet employed.

Referring' now to Fig. 1, the heater comprises a cylindrical casing 1 closed at one end by tube sheet 2 and at the other end by the cap or cover plate 3. A plurality of tubes 4 are expanded at, one end into tube holes 5 in tube sheet 2, which, as will be evident from Fig. 3, are divided into a number of spaced' groups for a purpose which will become clear later.

At their other ends, tubes i are expanded into semi-circular tube sheets 6and'7, these tube sheets being separated diamet-rically along the plane of the paper in Fig. 1" and frecly movable with respect to each other and .the casing 1 to allow for expansion of the tubes 4. As viewed in Fig. 1 the curved front edge of the tube sheet 6 is seen, while the part of 7 which is seen is' the straight vertical edge.

The semircircular headers 8 and 9 are secured respectively to the outer faces of semi-circular tube sheets 6 and 7. Of these' headers, the upper part of' the figure shows the front 'rounded surface of' the front header, and at the lower part 'of the figure the Vertical flat surface of the rear header is seen.

-The fixed tube sheet 2 has bolted to its outer face a semi-circular header 10 and a pair of quarter-circular headers ll and 12, header 11 beingprovided with an inlet connection 13 and header 12 being provided with a similar outlet connection 14.

As previously noted, the semi-circular headers 8 and 9 are bolted to tbe sleets 6 and 7 with the 'line of division vertical, while as* shown more clearly in Fig. 2 the line of division between header 10 'and headers 11 and 12 is horizontal and the line of division between headers 11 and 12 is vertical.

With this arrangement of the headers it will be readily apparent that four passes through the bundle of tubes 4 are provided. Assuming the inlet to be through connection SUPER- 13, the first pass is through the group of tubes i covered by header 11, thence upwardly through semi-circ lar header 8, back through the tubes connecting the upper end of header 8 with the left-hand side of header 10, thence through header 10 and the tubes covered by the right half thereof to the upper end of.

header 9, downwardly through header 9 and finally back through the tubes connecting the lower end of header 9 with the quarter-header 12.

Inlets 15 are provided in casing 1 fol-the I adnission of steam or other heating medium, and a dran 16 s provided for the removal of condensate,

The structure so far described is not novel,

and prior to my invention considerable difficulty has been encountered in *maintaining a joint between tube sheet 2 and the headers Secured thereto which would remain tight under a fluid pressure .of high magnitude such as that encountered when the heater is located between a boiler feed pump and the boiler. For this articular class of service' a metal to metal ]0l1t has been found more satisfactory than any knownform of packed or gasket joint, and in the-heretofore best 'known practice the outer face of tube sheet 2 is finished to an accurate plane surface, as are the bottoms of the headers to be Secured thereto, and the headers and tube sheet as sembled by direct bolting of the headers to the tube sheet without the use of any gasket or packing at the joint.

u groove may vary between wide limits with Experience has shown, however, that while a single header may be satisfactorily bolted to a tube sheet as, for example the bolting of headers 8 and 9 to the tube sheets 6 and 7 and a tight joint maintained, leakage occurs if it is attempted to bolt a plurality of headers to a single integral tube sheet. Taking the header and tube sheet assembly shown in Fig. 2 ..for example, the header 10 can be bolted to the tube sheet and a tight joint maintained as long as the adjacent headers 11 and 12 are not bolted to the tube sheet, but upon the latter being bolted to the tube sheet and drawn to a tight seat, the header 10 will almost invariably develop leaks at points 10"' and 10 which cannot be eliminated even by the application of the utmost permissible pressure to the header through drawing up of the bolts securing it to the tube sheet.

Although I do not desire to be in any way bound by such theory, it is my belief that this leakage is caused by the fact that the bolting of headers 11 and 12 to the face of the tube sheet sets up therein a fibre Stress which is transmitted through the tube sheet in a manner which distorts the latter and results in a non-plane surface under the semi-circular header 10. The latter is necessarily extremely stifl" in order to withstand the internal pressure exerted thereon in service, and its form, moreover, is such that it is extremely rigid so that it cannot be distorted by pressure apdepth of the groove is preferably at least one- While in the preferred form illustrated I plied through the securing bolts sufficiently to make it follow a non-plane tube sheet surface.

I have successfully overcome the difliculty -due to the above phenomenon by providing a rabbeted groove 17 in the outer face of the tube sheet .between the half header 10 and the quarter headers' 11 and 12. The depth of this groove and the inner face of the tube sheet..

as representedby' 17' necessary to withstand the service pressure wthin the casing 1. The minimum'depth of groove' required is determined by the character of the 'metal from which the tybe sheet is made, but in the case of the isual steel tube sheet, the.

third of the thickness of'the tube sheet.

have shown a groove of`rectangul-ar section, it will be obvious that the invention can be carried into effect by the use of grooves of other sectional form.

A second groove 18 is referably provided i 4 between the quarter hea ers 11 and 12 for the purpose of preventing the transnission of fibre Stress' from the surface under any one header from being transmitted to the surface ,experience that the most satisfactory results are obtained if each individual header secured to a given tube sheet. is separated by means of a groove in the face of the tube sheet from all other headers secured" thereto.

It is to be understood, however, that such separation of each header y from all other headers secured to the same tube sheet is not in all cases necessary to secure the desired object of the invention, and it is further to be understood that the invention is in no way limited to the form of apparatus chosen hereinfor illustrative purposes but may be applied equally well to any form of apparatus where a plurality of headers are secured to an integral tube sheet.

I claim:

1. As a new article of manufacture, a tube sheet provided with a plurality of spaced groups of .tube holes and a*groove in one face of the tube sheet located between and separating two of the groups of tube holes.

2. As a new article of manufacture, a tube sheet r provided with a generally circular group of tube holes spaced along a diameter of the circle to form separated generally semi-circular tube groups and a groove in one face of the tube sheet along the diametral space between said tube grooves.

3. As a new article of manufacture, an in tegral metallic tube sheet provided with three spaced groups of tube holes, one of said 'groups being generally semi-circular in outgroove in one face ofthe header located on the diameter of the tube sheet separating the semi-circular group of tube holes from the quarter-circular groups of tube holes.

4. As a new article of manufacture, an integral metallic tube sheet provided with three spaced groups of tube holes, one of said groups being generally semi-circular i-n outline with the other two of said groups being "generally quarter-circular. in outline, a

groove in one face of the header located on the diameter of the tube sheet separating the semi-circular group of tube holes from the quarter circular groups of tube holes, and a groove in the same face of the header located on the radius separating the quarter circular groups of tubes.

5. In apparatus of the class described, a plane metallic tube sheet, a plurality of spaced groups of tubes secured therein, a plurality of headers secured to one face of iso said tube sheet, and -a groove in the face of i the tube sheetto which the headers are secured, said groove lying betweenand separatingtwo of said headers.

6. n tube sheet, headers bolted to one face of said 'tube sheet and grooves in the face of the tube 'sheet to which the headers are bolted, said apparatus f the class described, a

grqoves Being located so that each heaer is separated by a groove from each of the other headers.

7. In apparatusof the class described, a tube sheet having a plane face, two heaers bolted to said face, each of said heaers having a straight wall relatively' closely space& from and substantially Parallel to a corre sponding wall of the other header, and a straight groove cut in said face between said walls.

8. In apparatus of the class described, a tube sheet having a, plane face, three headers bolted to said face, each of said headers hav ing a straight wall relativel closely space@- from and substantially para lei to a straight wall of eachof the remaining headers, and straight grooves cut in said face between each pair of adjacent header WaHs.

CHARLES W. GORDQN.,

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