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 consists of improvements in the construction and in the organisation
of parts of steam boilers of the water-tube kind in which, as exemplified in the
well-known Babcock & Wilcox type of water-tube boiler, the several tubes of a
series extending longitudinally over a furnace and through a flame chamber are
connected at their ends to headers or end pieces which communicate with a drum
or drums forming a reservoir or reservoirs for the water which circulates through
the tubes and for the steam generated therein.
My present invention is in part a further development of the improvements in
steam boilers, of the kind above referred to, described in the Specification of Letters
Patent No 12,189 of 1884 granted to me, and it has for object to simplify and
improve the construction of steam boilers of that class.
In the accompanying drawings, which serve to illustrate my invention, figure 1
is a sectional side elevation, figure 2 a front elevation, and figure 3 a transverse
vertical section of the improved boiler; figures 4 and 5 are transverse sections of
the steam and water drum or reservoir, showing different methods of connecting
the water box through which communication between the drum and the headers is
established; figures 6, 7, 8, 9 and 10 are vertical sections of various modifications
of an improved construction of the drum ends which have formed in them man-
holes each with a ring face serving as a seat for the manhole door as hereinafter
described and figures 11 and 12 are longitudinal and transverse sections of the
mud drum wbich is also of improved construction.
The improved boiler consists of a series of inclined water tubes A, whose ends
are expanded into orifices formed for their reception in headers or end pieces B, B¹,
which may be of cast metal or of malleable metal as described in the Specification
of Letters Patent granted to me and above referred to, and which are suspended
from a steam and water drum or reservoir C, by means of connecting tubes D, D¹,
expanded into orifices in the upper ends of the headers and in the lower sides
of the water boxes E, which are rivetted, nippled or bolted to the under side of
the druin near its ends.. The water tubes A extend lengthwise over a furnace F,
and within a flame chamber or combustion chamber G, which is enclosed by side
and end walls and of which the roof or crown is formed in whole or in part by the

page_text: drum C. The fire gases rising from the furnace F, ascend through between the
water tubes A into the flame chamber G, pass round a bridge or wall H, descend
between the tubes at the rear end of said chamber and after parting with their
heat to the tubes A pass off by a flue I, to a chimney. When, as shown, only a
single flame bridge H, across the tubes, is provided, a thin wall J of brickwork or
a facing of refractory material is built up between the tubes D¹, and in front of the
header B¹ and the mud drum K, to prevent the action of the fire gases upon the
descending column of solid water in the rear tubes D¹ and to avoid interference in
the slightest degree with the circulation of the water through the boiler.
The connecting water boxes E, are suitably formed to fit the under side of the
drum C to which they are rivetted or bolted by flanges formed on them as shown
in figure 4. Each water box extends transversely over the row of tubes by which
it is connected to the beader or end piece below and it is formed with as many
passages as there are connecting tubes. An inwardly projecting flange or socket e
is formed for the reception of each tube which is expanded into the orifice by a
mandrel or similar device. For convenience in transport the connection between
the water boxes and the drum may be formed as shown in figure 5, by short tubes
or nipples expanded into orifices in the boxes and in the lower side of the drum so
that the parts may be carried separately and be connected when the boiler is
erected. A suitable strengthening strip fis rivetted to the drum at the part of
the shell where the connecting nipple orifices are formed.
The ends of the steam and water drum are formed from single plates of
wrought iron or steel and they are dished out or pressed to the form shown by
hydraulic pressure or other means, the object of so dishing the ends being to obtain
great strength combined with lightness in the construction of the drum. The ends
are rivetted or otherwise attached in the usual way to the cylindrical shell of the
drum. These dished ends are made of increased thickness and in one of them a
manhole c is specially formed by means of suitable dies which are adapted to press
and cut the plate and form on it a lip or ring face c¹ which is subsequently faced
to serve as a seat for the manhole door, the increased thickness compensating for
the weakening of the plate by the cutting out of the manhole. The manhole door
seat is preferably formed by pressing out the plate to either of the dished forms
shown in figures 6 and 8, before cutting out the manhole, and thereafter com-
pressing or bending over the cut edges as indicated in figures 7, 8 and 9, to increase
the width of the ring face c¹ which serves as the door seat. The operations of
dishing and pressing or bending over the cut edges of the metal impart to the plate
such additional stiffness or strength as to effectually resist the internal pressure
upon the door which in the absence of such dishing or beading would tend to bulge
the plate. This construction of the drum end has also the advantage of providing
a door seat of any desired breadth by creasing or bending over the edges of the
plate as indicated instead of by rivetting or otherwise attaching a separate strip of
metal to the plate; and in this way a drum head or end with its requisite manhole
and door seat is obtained in a single piece at less cost and presumably of more
mechanically substantial construction than the ordinary drum end on which the
door seat is rivetted.
In lieu of suspending the drum by eye bolts or hooks in the ordinary way
I support the rear end of the drum upon a bracket L, resting on a girder L' carried
on columns L' such bracket being rivetted or otherwise suitably secured to the end
of the drum and being provided with projecting lips or flanges on the lower side to
engage the girder and secure the drum in its place. The front end of the drum is
supported by a rocking plate or carrier M whose lower end is rounded and rests in
a channel formed in a sole piece N fitted on the front girder O which is carried by
wrought iron columns P over the doorway Q which gives access to the headers B,
and the ends of the water tubes. The carrier M is free to oscillate on its lower
resting edge to a slightly inclined position on either side of its normal vertical
position in order that no obstacle may be presented to the free elongation or
contraction of the drum due to the action of the fire.

page_text: The front of the boiler is formed in the usual manner but in lieu of employing
the heavy ornamental cast iron side columns, cornice and crossbeam of the ordinary
form of Babcock & Wilcox boiler, the wrought iron columns P and girder O, which
support the boiler at the front, are utilized for attaching the door Q, that gives
access to the ends of the tubes, and the fire door piece R, the faces of the columns
and girders serving as closing surfaces for the door, and a cross beam S being
provided at the lower edge of the door for this purpose and to engage the fire door
piece.
Instead of employing the ordinary cast metal mud drum, I, in certain cases,
construct the mud drum K of malleable metal, which may be made in the form
shown in detail in figures 11 and 12 with a flattened surface on the upper side
wherein are formed the orifices serving as means of attachment to the rear headers
by tubes or nipples k expanded therein and into said orifices. The mud drum is
by preference made weldless throughout, or it may be in the form of a weldless
shell with one end welded in and the other rivetted as shown, or with both ends
rivetted or similarly secured thereto, the flattened upper surface being formed in
drums of small diameter.
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. The arrangement or organization of parts constituting the improved water
tube steam boiler herein described with reference to the drawings annexed.
2. The arrangement in combination with the steam and water drum and the
headers or end sections of a water-tube boiler, of the water boxes E, connected to
the under side of the drum by rivetted flanges or by means of short tubes or nipples
expanded into orifices in the boxes and in the drum substantially as herein
described with reference to the drawings annexed.
3. An end piece for a drum or reservoir dished or pressed and cut in such a
manner as to form from a single plate of malleable metal a complete drum head or
end with its manhole and door seat, substantially as herein described with reference
to the drawings annexed.
4. An end piece for a drum or reservoir dished or pressed and cut to the form
shown in figure 10, and having shrunk thereon a metal ring to increase the width
of the manhole door seat, substantially as herein described.
5. The improved means herein described and illustrated for supporting the steam
and water drum or reservoir of a water-tube boiler to provide for the elongation
and contraction of the drum.
6. The improved arrangement of the supporting columns and cross beams serving
to carry the front end of the drum and forming means of attachment and closing
faces for the tube door and fire door piece constituting the "front" of a water-
tube boiler, substantially as herein described with reference to the drawings
annexed.
.7. The improved construction of mud drum of malleable metal substantially as
herein described.