US3592171A

US3592171A - Boiler penthouse

Info

Publication number: US3592171A
Application number: US853903A
Authority: US
Inventors: Martin D Bernstein
Original assignee: Foster Wheeler Inc
Current assignee: Foster Wheeler Inc
Priority date: 1969-08-28
Filing date: 1969-08-28
Publication date: 1971-07-13
Anticipated expiration: 1988-07-13
Also published as: ES188757U; ES188757Y; GB1324817A

Abstract

A pressurized penthouse which is joined to the top of a boiler and which retains internal pressure even when the boiler expands substantially more than the penthouse. The overhang of the penthouse is provided at each corner with corrugations which permit expansion of the boiler without the development of leaks in the penthouse.

Description

United States Patent DH l l inventor Martin D. Bernstein Bro-x, N.Y. Appl No 853,903 Filed Aug. 28. 1969 Patented July 13, I971 Assignee Foster Wheeler Corporation Livingston, NJ.

BOILER PENTHOUSE 5 Chime, Drawing Figs.

[1.8. CI 2/494 F22!) 37/36 l 22/6 A.

[ 5 6 Referenees Cited UNITED STATES PATENTS 3 479 994 ll/l969 Kreider eta]. r. l22/494 [986,667 l/l935 Bailey l22/235 Primary Examiner--- Kenneth W Sprague At!0rneys-J0hn E, Wilson, John Maier, Ill and Marvin A.

Naigur ABSTRACT: A pressurized penthouse which is joined to the top of a boiler and which retains internal pressure even when the boiler expands substantially more than the penthouse. The overhang of the penthouse is provided at each corner with corrugations which permit expansion of the boiler without the development ofleaks in the penthouse.

PATENTED JUL I 319m 3.592171 sum 3 BF 3 IIIIIIIlI/III/l/j/LI l/[LllI/II/IITIIII/ITII INVEN'I ()R 28 FIG 4 BY MARTIN D. BERNSTEIN 54/1 JOHN 5 WILSON ATTORNEY BOILER PENTHOUSE BACKGROUND OF THE INVENTION In a modern large boiler, pipes and/or other conduits which join several of the boiler sections often project upwardly over the top of the boiler. To prevent heat losses, the conduits are often insulated by means of a penthouse which covers the top of the boiler.

In such an arrangement. problems have been encountered because gases which are generated within the boiler escape into the penthouse. This problem is serious because the gases are corrosive. To prevent such leakage, the interior of the penthouse is often pressurized so that if the interiors of the boiler and penthouse communicate, the corrosive gases will not pass into the penthouse.

Maintaining pressure inside of the penthouse is complicated by the fact that the boiler expands more than does the penthouse during operation. The difference in the degree of expansion between the boiler and penthouse is due to the fact that the penthouse is insulated from the high boiler temperatures. Therefore, a rise or fall in boiler temperature will not induce a corresponding significant temperature change in the penthouse. Consequently, the boiler expands and contracts during operation much more than the penthouse and thus joining the boiler and penthouse so that no leakage develops between them is often a difficult if not impossible task.

A type of penthouse which is in common use today is one which projects outwardly beyond the boiler and which uses a flat horizontal bottom wall extending inwardly from its sides to the outer wall of the boiler. An expansion hump which may be more or less Ushaped is usually provided in the horizontal wall of the penthouse so that it passes completely around the boiler. Such a joint will permit the sidewalls of the boiler to push outwardly against the bottom wall of the penthouse without all of the displacement at the inner portion to the bottom wall being transmitted to the outer portion thereof.

It must also be appreciated that in a large boiler installation. both the penthouse and the boiler are generally hung from structural members by elements which are heated by heat conducted from the associated boiler or penthouse. Since the elements which connect the boiler to those structural members will be heated to a higher temperature than the temperature of the elements which connect the penthouse to such members. the boiler will sag downwardly more than the penthouse during operation. Moreover, for any given increase in boiler tem perature the boiler will descend more than the penthouse because the penthouse is insulated from the boiler. so that its sidewalls will not expand downwardly as much as the boilers sidewalls. This relative motion between the penthouse and boiler is also compensated for somewhat by the expansion hump in the bottom wall ofthe penthouse.

One problem which has not been solved satisfactorily is due to the fact that the bottom wall of the penthouse, being shaped generally as a rectangle, is made up of straight segments. each of which is expanded along its length as well as being pushed outwardly under the action of a heated boiler. The longitudinal expansion of the straight segments creates substantial straining in the corners of the bottom wall, that is. in the areas where the straight segments meet. In the past this has caused leakage to develop between the penthouse and boiler and/or between the penthouse and atmosphere.

SUMMARY It is an object of the present invention to overcome the problems found in the prior art such as those discussed above. The bottom wall of the penthouse is provided with corrugations adjacent to the corners thereof to permit relative movement between the boiler and the penthouse without the development of leakage between the penthouse and the atmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective fragmentary view of a portion ofa penthouse made in accordance with the present invention;

FIG. 2 is a fragmentary view, partly in section. of the present penthouse mounted on top of a boiler;

FIGv 3 is a fragmentary plan view of the portion of the present penthouse which is shown in FIG. I; and

FIG. 4 is a fragmentary plan view similar to FIG. 3. but showing another embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The structure which is shown in some detail in FIG. 1 may be incorporated in a penthouse 10. which, as shown in FIG. 2, is adapted to be mounted on top ofa boiler 12, to insulate the piping and/or other conduits which pass over the top of the boiler from the atmosphere to thereby prevent heat loss. The penthouse 10 has outer walls 14 which project vertically. as do outer walls 16 of the boiler 12.

It has already been explained that when the boiler 12 is heated. the walls I6 expand outwardly and because the boiler 12 is suspended from overhead structure such as beam 18 by elements such as tie rods 20 which elongate when heated by the boiler, the walls 16 drop somewhat in relation to the outer walls 14 of the penthouse Ill. (The penthouse of course. picks up little of the boiler heat so that its associated tie rods 22 do not elongate significantly.) This relative movement and the resultant adverse effect on the penthouses capacity to prevent leakage of the pressurized air within has been ameliorated somewhat by a U-shaped hump 24 in the penthouse 10 which encircles the boiler 12 between the penthouse sidewall 14 and boiler sidewall 16. The hump 24 has a top portion 26. a downwardly extending inner sidewall 28 and a downwardly extending outer sidewall 30. The

sidewalls

28 and 30 merge with the top portion 26 and extend downwardly to the bottom wall 32 which has an inner portion 34 and an outer portion 36. The inner portion 34 of the wall 32 has an inner edge 35 which is joined to the sidewall 16 of the boiler 12 as shown in FIGS. 2 and 3. The outer portion 36 of the wall 32 extends outwardly to the outer wall 14 of the penthouse 10. It will be apparent that the bottom wall 32 is made up of four straight segments which form a rectangle.

It also has already been explained that when the walls [6 of the boiler 12 expand they are moved outwardly as they increase in width. An increase in width of the sidewalls l6 tend to elongate each of the straight segments of the inner portion 34 of the bottom wall 32 of the penthouse II] and consequently each straight segment of the outer portion 36 of the bottom wall 32. This tends to create large stresses in the corner areas 38 (FIGS. 1 and 3) which can result in failure and thus leakage of the pressurized air within the penthouse 10 either at those areas or between the edge 35 and the boiler sidewall 16. It is also possible that stresses will be transmitted over the outer portion 36 sufficiently to cause a leak between it and the outer wall 16 or between the outer wall 14 and the top deck of the penthouse 10. And it is also possible for such stresses to cause failure between the straight segments of the sidewall 14.

As shown in FIG. 3. a point F on the top 26 of the hump 24 will move outwardly to F because of the outward expansion of the boiler 12 at the outer walls 16. The hump 24 will prevent most of this outward displacement from being transmitted to the outer portion 36 of the bottom wall 32 of the penthouse 10. Consequently a point D on the outer periphery of the top portion 28 will move substantially only along a line which is parallel to the sidewall M5 to settle at D.

The hump 24 has outer corners 40 and inner corners 42. A point C close to a corner 40 of the hump 24 will move outwardly in a direction at an angle to the sidewall Hi to point C as the outer side 30 expands to the position shown in dashline in FIG. 3 due to the longitudinal expansion of the two contiguous straight segments of the bottom wall 32 and the resultant outward component of expansion in the corner area 38. This action creates a large degree of distortion in the bottom wall 32 in the corner area 38. To prevent this distortion from being transmitted out to the outer wall 14 of the penthouse to severely strain the penthouse l0, corrugations 44, 46, 48 are provided. These corrugations are preferably curved so that they are in a position to take up strains on the corner area in the direction generally diagonal to the rectangle formed by the bottom wall 32. The amount of distortion is probably less at the corrugation 46 than it is at the corrugation 44 and the distortion at the corrugation 48 is probably less than the distortion of the corrugation 46. The distortion is probably greatest at the central portion of each corrugation as they move to the position shown in dot-dashline in FIG. 3.

In the preferred embodiment,

auxiliary corrugations

50 and 52 extend perpendicular to the sidewalls 16 of the boiler 12 in the penthouse bottom wall 32 close to the corner areas 38. These corrugations help to permit the outer portion 36 of the bottom wall 32 adjacent to the sidewall to move toward the corner 40 without transmitting this distortion to the outer wall 14 of the penthouse 10. If the bottom wall 32 is to be provided with a maximum ability to withstand distortion in the corner area 38 thereof. added

corrugations

54, 56, 58 and 60 can be provided as shown in FIG. 4, so that each of the curved corrugations are contiguous with one another. Similarly, corrugations 62 and 64 can be provided in the outer portion 36 of the bottom wall 32 perpendicular to the outer wall 30 of the hump 24 to further prevent the linear expansion of the sidewall 16 of the boiler 12 from being transmitted to the outer wall 14 ofthe penthouse ll] and to prevent separation of the outer wall 14 from the penthouse [0, To prevent failure of the hump 24 between its corners 40 and 42 and to take up some of the diagonal strain in the comer area 38 along with the

curved corrugations

44, 46 and 48, a corrugation 66 is provided in the top 26 of the hump 24,

It is to be understood that the foregoing describes only one preferred embodiment of the present invention and that other embodiments will be apparent to a person of ordinary skill in the art which will be within the scope of the present invention.

1 claim:

IV A component for a boiler penthouse which penthouse is adapted to cover a boiler having a sidewall, said component having an inner edge with straight portions and corners to permit said edge to be connected with said sidewall of the boiler, a corrugation in said component adjacent to one of said corners to prevent distortion induced in said component by expansion of said sidewall in a direction generally diagonal to said corner from causing rupture in said component, and an auxiliary corrugation in said component extending generally perpendicular to said edge,

2, The component defined in claim 1 wherein said auxiliary corrugation is adjacent to an end of said corrugation adjacent to said corner 3. The component defined in claim I wherein said corrugation adjacent to said corner is one of a plurality of such corrugations each being laterally spaced from the others, with one of the ends of each adjacent to said auxiliary corrugation.

4. The component defined in claim 3 wherein said corrugations adjacent to said corner are curved about said corner,

5. The component defined in claim 4 further comprising another auxiliary corrugation, said auxiliary corrugation being positioned adjacent to the other ends of said corrugations adjacent to said corner.

Claims

1. A component for a boiler penthouse which penthouse is adapted to cover a boiler having a sidewall, said component having an inner edge with straight portions and corners to permit said edge to be connected with said sidewall of the boiler, a corrugation in said component adjacent to one of said corners to prevent distortion induced in said component by expansion of said sidewall in a direction generally diagonal to said corner from causing rupture in said component, and an auxiliary corrugation in said component extending generally perpendicular to said edge.

2. The component defined in claim 1 wherein said auxiliary corrugation is adjacent to an end of said corrugation adjacent to said corner.

3. The component defined in claim 1 wherein said corrugation adjacent to said corner is one of a plurality of such corrugations each being laterally spaced from the others, with one of the ends of each adjacent to sAid auxiliary corrugation.

4. The component defined in claim 3 wherein said corrugations adjacent to said corner are curved about said corner.