IMPROVEMENTS IN STEAM BOILERS
Year: 1878

page_text: LETTERS PATENT to Sydney Pitt, of Sutton, in the County of Surrey, for the
Invention of "IMPROVEMENTS IN STEAM BOILERS." A communication from
abroad by John Baird, of the City of New York, in the United States of
America.
Sealed the 8th March 1878, and dated the 16th January 1878.
COMPLETE SPECIFICATION filed by the said Sydney Pitt at the Office of
the Commissioners of Patents on the 16th January 1878.
SYDNEY PITT, of Sutton, in the County of Surrey.
"IMPROVEMENTS IN STEAM
BOILERS." A communication from abroad by John Baird, of the City of New
York, in the United States of America.
These boilers are intended chiefly for use in steam vessels, either for inland
navigation or sea going, but may be used advantageously in connection with
stationary engines.
At the present day the use of high steam is general; it is therefore necessary to
have a boiler which will bear a high pressure, and expedient that this boiler should
bear such pressure with the aid of as little staying or bracing as possible.
When boilers are used in the holds of steamships, it is also desirable that they
should be constructed in sections, so that they may be taken out of the hold and
replaced therein when necessary through the ordinary hatchways, thereby obviating
the necessity of removing and replacing the deck and deck beams, which usually
exists when boilers of the ordinary type are employed.
The boiler which constitutes the subject of this Patent is composed of at least
three sections, so constructed that these three make up one boiler, and that by the
use of additional sections a battery of boilers, which will furnish any desired quantity
of steam, may be constructed; moreover, each larger or main section is composed
chiefly of a continuous cylindrical shell, which needs no bracing except that for the
heads thereof, at such places as these heads are not braced by the tubes.
The main or larger section of the boiler consists, in fact, of a cylindrical shell
C

page_text: any water legs depending from the sides of the shell.
The supplemental or smaller sections of the boiler are thin boxes of iron or steel,
having, by preference, the form of truncated wedges, the sides of which may be
braced together by ordinary screw bolts or socket bolts, in the way that the water
legs of locomotive boilers are braced. These latter sections are constructed entirely
independent of the former or main sections, and when the sections are put together,
as hereafter described, with each main section between two supplemental sections,
connections between the steam and water spaces of the several sections are made by
proper pipes.
In the Drawings,-
Figures 1 and 2 are longitudinal vertical sections through the main sections of
two modifications of the boiler.
Figure 3 is a front elevation of the boiler.
Figure 4 is a similar elevation with certain fittings removed.
Figure 5 is a rear elevation of an extension of the modification shown at
Figure 2.
Figures 6 and 7 are respectively side and end views of one of the supplemental
water spaces or sections.
In the Drawing the cylindrical shell of the main section is shown at a, a, with
two flat water legs, as at b, b, depending therefrom and secured thereto in the way
that such water legs are usually secured to cylindrical shells. Each of these shells
contains a back connection c and tubes d, d, and may also contain a forward con-
nection leading to the chimney, or may have the forward connection bolted on
outside of the shell (as shown at e, Figures 2 and 3), which is the construction of
front connection that is preferred. These front water legs are provided with openings
ff, through which coal may be fed to the grate-bars, and if the legs descend below
the grate-bars with other apertures g, g, for admitting the air below the grate-
bars.
In order to insure a full supply of water to the rear end of the tubes, the rear
water leg may be connected with that part of the shell which is below the rear
end of the tube by pipes h, h, but these pipes are not considered as absolutely
necessary.
•
When these main sections are to be used on land or in iron steamships it is
preferred to make the hearth below the grate-bars, the bridge wall, and the bottom
of the back connection, of brick, as shown in Figure 2; but when the boilers are to
be used in wooden vessels, it is preferred to bend the rear water leg forward under
the back connection to form a bottom to the back connection, thence downwards to
form a bridge wall, and finally forwards to form the bottom of the hearth until it
connects with the bottom of the front water leg, all as represented in Figure 1.
The secondary or smaller sections, which make up the boiler, are represented at
k, k (Figures 3, 4, 5, 6, and 7), and, as before stated, are boxes of sheet metal properly
stayed, and, by preference, shaped like truncated wedges, with their larger ends
uppermost, so that the steam formed in them may rise freely to the upper part of
these supplementary sections. These secondary or supplementary sections rise above
the usual water level in the main sections, in order that the water may be at the
same level in both, and that there may exist a practical steam space in the supple-
mentary sections.
It is obvious that the main sections (those first described) could not of themselves
alone be used as steam boilers, because the fire-boxes would be open at the sides,
and the same would be the case with the back connections.
When it is desired therefore to construct a boiler of these sections, two supple-
mentary sections are placed one on each side of a main or larger section, as shown
in Figure 3, thus completing the fire-box and back connection; and if the boiler
then should be of too small size, a second main section and a third supplementary
section may be added thereto, as shown in Figure 5, and so on in succession until a

page_text: battery or series of boilers competent to produce the required supply of steam is
obtained.
All the main sections may communicate through their front connections with a
common chimney or smoke pipe, and through proper appertures and pipes, as at 1, 1,
Figure 3, with a common steam pipe, and the several sections must be fastened to
each other in some proper manner.
The fastening is effected, by preference, by bolting pieces of boiler iron m, m,
Figure 3, to the ends of the shells, and to the front and rear of the water legs of the
main sections, and by bolting these same pieces to the front and rear ends of the
secondary sections, thus uniting all the sections of a series firmly together and in
such manner that any section can be removed by unbolting these pieces of heavy
boiler iron and disconnecting the steam and water connections.
The upper part of each of the smaller sections must be connected with either the
main steam pipe or with the steam space of the adjoining main section, or (in case
more than one main section is used) with both the adjoining main sections if deemed
best; and the lower part of each smaller section must also be connected with the
adjoining leg or legs of the main sections, or else directly connected with the feed
pipe; the latter plan is not preferred, as it involves the use of water gauges or
gauge cocks on the supplementary sections, and it is believed that these may be
dispensed with, and that means for ascertaining the height of the water need be
applied to the main sections only, provided the water legs of the latter are connected
with the lower parts or water spaces of the supplementary sections.
The crevices between the main and the supplementary sections may be made
perfectly tight, if desired, by fire lute or any of the ordinary cements used in soft-
patching boilers.
It is not deemed necessary to describe any special way of connecting the steam
and water spaces of the sections with each other, or with a common steam pipe,
or with feed pipes, as various modes of making such connections are well-known
to engineers.
A careful consideration of this description and the Drawing will show that the
boiler herein described is strong, compact, and easy to be put in position or
removed for repairs, while at the same time it is comparatively cheap and free
from expensive bracing.
What is claimed as the Invention is, the compound boiler, composed of a main
section having a shell and water legs, and of supplementary sections extending
above the water level in the larger section, all constructed and put together
substantially in the manner herein-before described and represented in the
Drawing.
In witness whereof, I, the said Sydney Pitt, have hereunto set my hand
and seal, this Eighth day of January, in the year of our Lord One thousand
aight hundred and savanty-eight