US2035605A - Boiler construction - Google Patents

Description

March 31, 1936. R N- 2,035,605

BOILER CONSTRUCTION Y Filed Aug. 5, 1935 2 Sheets-Sheet l 7 4 6 j mi? Fez-'07 Jackson March 31, 1936. P. JACKSON BOILER CONSTRUCTION Filed Aug. 5, 1935 2 Sheets-Sheet 2 3mm F91": Jac'k'an Patented Mar. 31, 1936 U l'lE ill:- STATS PATENT OFFIQE BOILER CONSTRUCTION tion of Kentucky Application August 5, 1935, Serial No. 34,825

7 Claims.

This invention relates to improvements in boiler construction.

It has-for its general object the provision of a boiler having front and rear tube supporting heads so constructed as to be self-supporting without necessitating the employment of the customary internal bracing members either above or below the tube sheets. The elimination of such braces avoids the presence of obstructions in the water and steam spaces of the boiler and makes these spaces much more accessible for cleaning.

Another object of the invention is to provide front and rear heads, the tube sheet portions of which are flat and parallel whereby all the tubes are of the same length. This is an obvious advantage to the boiler manufacturer from the standpoint of cheapness and ease of manufacture, and all of the tubes are subject to the same longitudinal expansion and contraction under varying heat conditions, being thus relieved from differential strains. Furthermore, the fact that the tube sheet portions of the heads are flat and per-- pendicular to the tubes requires only that the tube sheets being perforated for receiving the tube ends and dispenses with the expensive necessity of providing seats in the tube sheets for the ends of the tubes.

Another object of the invention is the provision of a boiler head of general dished shape having a peripheral portion of spherical contour, a flat tube sheet area merging laterally directly into said spherical peripheral portion, the peripheral portion being extended to meet and merge with the lower boundary of the tube sheet portion, excepting where modified as will appear, to provide a manhole, the vertical geometrical elements of the underlying spherical portion being rotund and constituting said underlying portion an eificient and adequate compression member for supporting the tube sheets, the head being formed with an upper portion intermediate the spherical periphery and the upper boundary of the tube sheet, merging into the latter and into the contour of the spherical peripheral portion above it,

' said upper intermediate portion being transvers ly very slightly curved so that it may be correctly described as being substantially fiat, and having the curvature of those geometrical elements which lie in vertical planes, approximately flat, making the upper intermediate portion as an optimum tension member for suspending the tube sheets and the weight of the tubes.

Still another object of the invention is the provision of a manhole in the boiler head beneath the tube sheet portion formed in a reentrant spherical depression in the outwardly convex lower portion of said head, the spherical contour of the boiler head in said depression affording the best shape for resisting deformation or collapse adjacent the edge of said manhole.

Still another object of the invention is to provide a boiler having dished heads, the peripheral margins of which merge smoothly with the cy lindrical walls of said boiler.

Another object of the invention is to provide a boiler with heads of the type described joined thereto by welding whereby a smooth surface is provided on the inside of the boiler to facilitate cleaning.

Other objects of the invention will appear as the following description of preferred and practical embodiments thereof proceeds.

In the drawings which accompany and form a part of the following specification and throughout the several figures of which the same characters of reference have been employed to designate identical parts:

Figure 1 is a perspective view of a boiler illustrating a head embodying the principles of the present invention;

Figure 2 is an end view of the same;

Figure 3 is a longitudinal section through the boiler showing both heads, the intermediate part being broken away;

Figures 4, 5, 6 and 7 are vertical sections taken along corresponding section lines indicated in Figure 1;

Figure 8 is a horizontal section taken along the line 8-8 of Figure 2; and

Figure 9 is a section taken along the line 9-4! of Figure 2.

Referring now in detail to the several figures the numeral I represents a boiler which is here shown as being cylindrical having at the opposite ends heads 2 and 3, it being understood that since the invention concerns itself primarily with the construction of the head, it is immaterial Whether both heads of the boiler be alike or whether only one head embody the present inventive concept providing, in those concepts of the invention which envision the advantages of having the tubes of equal length, that the opposite end of the boiler provide a fiat tube sheet parallel with the tube sheet portion of the head which embodies the features of the present invention.

The head 2 is of general dished shape, outwardly convex and having its peripheral margin 4 preferably merging smoothly with the cylindrical wall of the boiler and being preferably buttwelded thereto as at 5 to provide a smooth inte rior surface for the boiler shell. The peripheral curvature of the head adjacent the margin 4 is spherical as indicated at 6 and l. The vertical sections illustrated in Figures 4, 5, 6 and '7 show that at the lower part of the head the spherical portion 1 extends outwardly and upwardly merging into the fiat tube sheet portion 8, the latter being preferably, although not necessarily, in a vertical plane. The tube sheet portion 8 as will be observed particularly in Figure 2 extends. preferably from a point above the horizontal diameter of the head to a point a greater distance below said horizontal diameter, defining a steam chamber 9 in the upper part of the boiler. The tube sheet portion being fiat, it is merely necessary to perforate it for the reception of the tube ID, the latter intersecting it perpendicularly and being preferably welded thereto. It is not necessary to form the tube sheet portion with depressions or seats for fairly receiving the tube ends as would be required providing the tubes metthe tube sheet portion in any other than a perpendicular relation. Since it is contemplated that the opposite end of the boiler will be provided either with a similar head or with a head providing a fiat tube sheet parallel to the tube sheet 8, the tubes l0 will all be of the same degree of expansion or contraction under equal heat conditions so that no differential strain is put upon the tubes or upon the boiler head itself. The vertical geo-- metrical elements of the underlying spherical portion I are of the very best shape to constitute the underlying spherical portion a compression member for upholding the weight of the tube sheet portions and tubes themselves.

The portion ll of the boiler head immediately above the tube sheet portion 8 is very slightly curved transversely so that it may be said to be substantially fiat, as is indicated in Figure 1 and Figures 4 to '7, inclusive, and the geometrical elements of said portion which lie in vertical planes are of such flat curvature as to be approximately rectilinear, constituting the portion I! a tension member of optimum shape to suspend and sus tain the weight of the tube sheet portions and tubes.

A manhole I2 is provided in the spherical portion of the head which underlies the tube sheet portion, said manhole being formed in a reentrant spherical depression 13 in the wall of said boiler head which spherical depression has the best possible shape to prevent distortion or collapse under the pressure generated within the boiler. Consequently, the edge M of the manhole which is a source of weakness in most boiler heads and has to be internally braced is thus made adequately strong and self-sustaining.

By the above construction a boiler head is provided which is self-supporting against thermal as well as hydrostatic or fluid pressure strains, thus enabling the manufacturer to dispense with the customary internal bracing, not only making an efiicient and stronger boiler, but leaving the water and steam spaces free from obstructions so that it canbe easily and completely cleaned through the access afforded by the manhole l2.

While I have in the above description defined what I believe to be a preferred and practical embodiment of the invention, it will be understood that the specific details of construction as shown and described are merely by way of example and not to be construed as limiting the scope of the invention as defined in the appended claims.

What I claim is:

1. Boiler comprising a shell having front and rear heads at least one of the heads being dished and having a flat tube sheet portion'and a spherical marginal portion, the fiat tube sheet portion merging into the spherical marginal per-- tion laterally and below, said head having 231 1 intermediate portion above said tube sheet por-' tion between the latter and the upper spherical marginal portion, said intermediate portion being substantially fiat in a transverse direction and of approximately fiat curvature in vertical planes said substantially flat portion being inclined at, an acute angle to the plane of the tube sheet for tensionally supporting the weight of said tube sheet portion and tubes, the opposite head having a fiat tube sheet parallel to the tube sheet portion of the other head, and tubes of equal length bridging the tube sheets.

2. Boiler comprising a curved shell having front and rear heads, at least one of the heads being dished and having a flat tube sheet portion and spherical marginal portion, the flat tube sheet portion merging into the spherical-margin-- al portion laterally and below, said head havingan intermediate portion above said tube sheet portion and between the latter and the upper spherical marginal portion, said intermediate portion being substantially flat in a transverse direction and of approximately fiat curvature in vertical planes said substantially fiat portion being inclined at an acute angle to the plane of the tube sheet for tensionally supporting the tube sheet portion and weight of the tubes, the opposite head having a flat tube sheet parallel to the tube sheet portion of the other head, and tubes of equal length bridging the tube sheets, the marginal portion of said head conforming to the curvature of said shell and registering with the end edges of said shell.

3. Boiler comprising a curved shell having front and rear heads, at least one of the heads being dished and having a fiat tube sheet portion and spherical marginal portions, the fiat tube sheet portion merging into the spherical marginal portion laterally and below, said head having an intermediate portion above said tube sheet portion and between the latter and the upper spherical marginal portion, said intermediate portion being substantially flat in a transverse direction and of approximately fiat curvature in vertical planes said substantially fiat portion being inclined at an acute angle to the plane of the tube sheet for tensionally supporting the tube sheet portion and weight of the tubes, the opposite head having a flat tube sheet parallel to the tube sheet portion of the other head, and tubes of equal length bridging the tube sheets, the marginal portion of said head conforming to the curvature of said shell and registering with the end edges of said shell, said head being welded to said shell and said tubes being welded to said tube sheet portion.

4. Boiler head comprising a dished member having a fiat tube sheet portion and a spherical marginal portion, the flat tube sheet portion merging into the spherical marginal portion both laterally and below, said head having an intermediate portion above said tube sheet portion, between the latter and the upper spherical marginal portion, said intermediate portion being substantially fiat in a transverse direction and of approximately fiat curvature in vertical planes said substantially fiat portion being inclined at an acute angle to the plane of the tube sheet for tensionally supporting said tube sheet portion.

5. Boiler head comprising a-dished member having a flat tube sheet portion and. a spherical marginal portion, the fiat tube sheet portion merging into the spherical marginal portion both laterally and below, said head having an intermediate portion above said tube sheet portion between the latter and the upper spherical marginal portion, said intermediate portion being substantially fiat in a transverse direction and of approximately fiat curvature in vertical planes said substantially flat portion being inclined at an acute angle to the plane of the tube sheet, for tensionally supporting said tube sheet portion, said head below said tube sheet portion being provided with a reentrant spherical depression bounding a manhead opening.

6. Boiler head comprising a dished member having a flat tube sheet portion and spherical marginal portions, the flat tube sheet portion merging into the spherical marginal portion laterally and below, the peripheral edge portion of said head being cylindrical, the geometrical cylindrical elements of which edge portion being perpendicular to said tube sheet portion, said head having an intermediate portion above said tube sheet portion and between the latter and the upper spherical marginal portion, said intermediate portion being substantially fiat in a transverse direction and of approximately fiat curvature in vertical planes said substantially flat portion being inclined at an acute angle to the plane of the tube sheet for tensionally supporting said tube sheet portion.

7. Boiler head asclaimed in claim 6, the cylindrical peripheral edge portion being of progressively increasing length from the top to the bottom of said head.

PERCY JACKSON.

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