Year: 1885

page_text: I, CHARLES ALBERT KNIGHT of the Babcock & Wilcox Company, 107 Hope
Street, in the City of Glasgow, Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
My invention relates to the class of steam boilers in which, as exemplified in the
well known Babcock & Wilcox water tube boiler, the steam generated in a series of
water tubes is collected in a drum or reservoir through which the water circulating
in the tubes and headers or end pieces to which they are connected may also pass
and partially fill it. In such boilers the steam and water drum is necessarily made
of comparatively small diameter owing to the ends which are formed of cast metal
being relatively weak as compared with the cylindrical shell of the drum when a
drum of large diameter is employed. The object of my invention is to make provi-
sion whereby the steam and water drum of the boiler may be largely increased in
diameter while maintaining the same high degree of safety as is usual in this type
of boiler when formed with a drum or drums of small diameter. To that end I
suitably taper the end parts of the cylindrical drum either uniformly round so that
the drum ends are each in the form of the frustrum of a cone, or on the upper sides
alone in order that a uniform level or inclination of the lower side of the drum may
be maintained; and in the ends which are thus considerably reduced in diameter I
secure, by rivetting or bolting, the cast iron or steel ends or end pieces which may
be of the ordinary form; or I secure in the ends of a cylindrical drum of large
diameter, annular or crescent-like plates of malleable metal on which are formed
flanges whereto I attach the cast metal end pieces.
The improvements constituting my invention are shown as applied to a water
tube boiler of the Babcock & Wilcox type in the accompanying drawings of which
figure 1, is a sectional side elevation and figure 2, a transverse vertical section
showing the taper ended drum; and figures 3 and 4, are sectional and end eleva-
tions of the modified form of the composite drum end. The boiler, as regards the
form and mode of connecting the various parts, is of the ordinary construction with
the exception of the steam and water drum or reservoir A which as shown in
figures 1 and 2 is formed with tapered ends A¹ A¹ to which cast metal ends or end
pieces B B are secured by rivetting or bolting in the ordinary way. The tapering
of the drum ends is in this example confined to the upper sides of the shell, the

page_text: lower side being maintained at a uniform level to avoid interfering with the circu-
lation of the water through the drum. The headers or end sections C or the water
boxes which serve as means of communication between the water tubes D, of the
boiler and the drum are connected either to the ends B, B, or to the under side of
the drum. By the improved construction described the main part of the shell of
the drum may be made of relatively larger diameter than usual and the end
pieces B, B being of comparatively small diameter and not exceeding the usual
dimensions do not present the increased element of danger in case of rupture by
accident that they would if made of a size adapted to close the ends of a cylindrical
drum of the large size which may advantageously and safely be used in the
improved form, and thus lightness combined with strength and increased capacity
are secured by the improved construction of the drum. The same object is attained
by securing in a cylindrical drum a composite end piece formed by attaching to the
drum end a flanged plate a, of malleable metal, and attaching thereto a cast metal
closing end piece b as shown in figures 3 and 4. The plate a may be of crescent
form as shown or it may be of annular shape and in either case is suitably stayed
if necessary.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. A water tube steam boiler having a steam and water drum or reservoir of the
improved construction herein described, whereby the diameter of said drum may be
safely increased, substantially as herein set forth.
2. In a water tube boiler a steam and water drum or reservoir having tapered
ends closed by end pieces of cast metal substantially as and for the purposes herein
set forth.
3. In a water tube boiler a steam and water drum or reservoir formed with
composite closing end pieces substantially as and for the purposes herein set forth.
Dated this Fourth day of December 1885.
CRUIKSHANK & FAIRWEATHER,
135, Buchanan Street, Glasgow,
Agents.