In- PROVEMENTS IN STEAM BOILERS AND FURNACES
Year: 1867

page_text: LETTERS PATENT to George Sinclair, of the Town of Leith, in the County
of Edinburgh, North Britain, Boiler Maker, for the Invention of "In-
PROVEMENTS IN STEAM BOILERS AND FURNACES."
Sealed the 7th January 1868, and dated the 12th July 1867.
PROVISIONAL SPECIFICATION left by the said George Sinclair at the
Office of the Commissioners of Patents, with his Petition, on the 12th
July 1867.
I, GEORGE SINCLAIR, of the Town of Leith, in the County of Edinburgh,
North Britain, Boiler Maker, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN STEAM BOILERS AND FURNACES," to be as
follows, that is to say:-
This said Invention consists, first, in constructing the main body or outer.
shell of steam boilers of two long chambers or vessels each made in the shape
or form of segments of hollow cylinders with either flat or domed ends, and
having their flat sides placed parallel and opposite to or facing each other
either vertically or horizontally, and firmly connected and stayed together by
longitudinal and transverse rows of vertical or horizontal tubes respectively
(accordingly as the two segmental parts of the boiler to be constructed are
placed longitudinally or vertically on end, side by side, or otherwise horizon
tally over each other) jointed at their ends into the flat sides of the vessels as
tube plates in any of the usual manners for so jointing tubes in boilers, and so
as to fill up the whole or nearly the whole of the parallel space between the

page_text: vessels, and form the great heating surface and main flue or chamber on which
and through which the flames and heated products of combustion would act
and pass respectively on leaving the furnace on their way to the chimney.
It is preferred to have one of the vessels or segments of rather more than the
half circle, and the other rather less, the larger one answering for the steam
receiver when placed over the other, and also allowing of the tubes being
inserted and withdrawn from its interior. The holes in the side plate of the
large vessel are larger than those in the smaller vessel in which the smaller or
point ends of the tubes are inserted from the outside of the plate and expanded
and rivetted on its under side within the vessel, or screwed or otherwise fixed
in the flat sides of both vessels, so as to stiffen or firmly stay and bind or "tie "
them in their parallel planes against the pressure of the steam within the
vessels or boiler, tending to bend the tube plates or sides towards each other
at the centre, or to draw them asunder from the ends of the longitudinal rows
of side tubes. When desired stays may be introduced at intervals amongst or
between the tubes for the further stiffening and binding the flat sides of the
tube plates. Angled iron or other stays may be rivetted or bolted at their
ends at intervals along the two sides of the vessels across the space occupied
by the tubes to the edges of the arcs of the two vessels so as to bind them
firmly together; to which side stays sheet iron sides may be portably fitted or
attached, or otherwise doors may be hinged closing in the whole sides of the
space between the two vessels forming the main shell of the boiler and con-
taining the tubes through which the water circulates between the vessels on
being heated on their outer surface by the flames and hot gases impinging on
them in passing through amongst them in the said inclosed space as so closed
in. The main heating chamber containing the tubes may also be inclosed
by walls of brickwork furnished with doors, which doors whether in the brick
walls or attached to the transverse stays before named are made suitable for
easy and frequent access to clean, inspect, and repair the tubes when necessary.
The boiler so constructed may be used for raising steam for motive power and
other purposes for which steam boilers generally are used by having any
ordinary fire-grate and furnace of brickwork built to and in front of it bound
or surrounded with iron plates when desired; from which furnace the flames
and heated gases of combustion pass over the flame bridge or wall, on through
the main chamber containing the tubes, on the outer surface of which they
impinge and give off their heat to the water within the tubes, which causes
the boiling water and steam to ascend up the tubes into the upper large
vessel where the steam is collected above the water level, which in this case
(namely; the tubes being understood to be vertical and the vessels placed in

page_text: horizontal planes one above the other) would reach a few inches above the
top tube plate leaving, the greater part of the upper vessel as a steam space.or
receiver. For the purpose of assisting the downward or return currents of
water to the lower vessel to compensate for the constant upward currents
through the main body of small heating tubes larger tubes, pipes, or cylinders
may be introduced connecting the water space of the upper vessel direct with
that of the lower vessel, either at intervals along the sides or at the back end, or
both if desired, in spaces between the two vessels left without small tubes for
the purpose, or otherwise at the extreme ends either at the front or back, such
pipe being partially exposed to the heated flames or gases or not, as desired.
Or by another arrangement a water space might be formed (of from six to
eighteen inches wide between the walls) by the shell of the boiler itself at the
extreme back end, the full width of and height between the upper and lower
vessels being filled with short longitudinal or angled tubes and stays ac-
cordingly as the water space is made vertical, or as preferred leaning outwards
at the top, the upper vessel being made rather longer than the under one for
this purpose; and a considerable space is preferred to be left without the
vertical heating tubes in front of the water space for the purpose of giving
access for jointing and repairing the front end of the tubes in the water space.
These several arrangements allow the hot gases to be taken away direct at
the back end of the boiler to the chimney, or be conducted down by a brick
fine at the back and along the under side of the lower vessel, so as to return
to the front acting on its lower surface, and be conducted laterally to the
chimney at or near the furnace. This back water space may also when
desired be made without the tubes through it, and the hot gases be taken
away laterally by the space without vertical tubes in front of the water space
and drooping flues at the sides to the longitudinal flue of the lower vessel,
Instead of the tube
aud from thence to the chimney as before described.
plates of the two vessels being straight.in the transverse section represented
by the chord of their segments they might be curved and the tubes made to
radiate to suit the curved plates, narrowest towards the interior of the larger
vessel, which would assist the insertion and withdrawal of the tubes. within it ;.
in this case it is preferred to make the lower vessel a little broader than the
upper one. For the purpose of better strengthening or staying the tube plates
or sides of the vessels, particularly when used for. high-pressure steam boilers,
a transverse row of tubes may be left out at intervals, and either inside or
outside transverse straight stays or rings of T or other good section of iron be
used for such staying purposes, firmly bolted or rivetted to them at these parts,
and hoops of Hat or other convenient section, of iron might be "shrunk"

page_text: or bolted over or round the outside of both vessels at these or other parts in
the length to bind them together, and the side doors enclosing the space in
which the tubes are placed might be hinged or otherwise portably attached
to the side or straight part of these binding hoops. When the main body of
a steam boiler constructed in accordance with these improvements, as berein
described, is used with the two vessels laying on edge, and the transverse tubes
connecting them laying horizontal or slightly inclined upwards at one end
so as to assist the circulation through them, then the bot gases escaping from
the main chamber at the back after acting on the tubes are returned or
conducted round by two flues in the surrounding brick work along the outside
of the two vessels so as to act on them and escape into the chimney at
the front part of the boiler; the main flue or chamber with the tubes in
this case arched or covered in by brickwork either with or without iron
plating, and provided with doors for inspection and cleaning the tubes, and
having a soot pit or. long deep recess below the tubes to receive the soot,
either falling from or scraped off the tubes (which may be fitted with any of
the usual arrangements of scrapers for the purpose, when desired) furnished
with suitable side or end doors for the removal of the soot.
In this arrange-
ment it is preferred to fill the whole boiler so constructed with the water, and
have one or more special large cylindrical steam receivers attached by large
pipes or cylindrical conduits to the two main side vessels, which steam
receivers when placed longitudinally may be made superbeating by conducting
a portion of the flames and hot gases along a flue beneath it or them, so as to
act on its or their under surface.
Another modification of this improved construction of steam boiler consists
in attaching a short cylindrical furnace boiler with two round flues in it of
just sufficient length to contain two grates of furnace bais of an area large
enough for the requirements of the main boiler to which the furnace boiler is
to be attached. The attachment is effected by one or more short cylindrical
or oval pipes or ducts directly bolted or rivetted to the lower water space and
upper steam space of the front end of the main boiler, and the back end of
the furnace boiler, the space between these two parts of the whole boiler so
combined (which is determined by the length of the connecting pipes) is cased
in with bricks to form a sufficiently large space or chamber behind the flame
bridges (of both furnaces, and placed at the extreme back end of the two flues
of the furnace part of the boiler) and the front of the body of the heating.
tubes in the main boiler for the commingling of the first dense cold gases.
evolved from the fresh fuel of the one furnace with the. bright or hot
gases
from the other. which should always be charged or fired with fresh fuel,

page_text: alternately for this
purpose. The gases thus mixed are caused to ignite and
burn with a bright flame before entering the chamber of heating tubes, which
in a great measure prevents the production or escape of smoke or unutilized
or unconsumed gas, which would, besides causing waste of fuel, do much,
injury to the conducting power of the tubes by coating them with smoke or
soot.
Any of the ordinary constructions of furnaces, whether of the smoke-
consuming class or not, which are applicable to flue boilers of the description
named, are also applicable to this part of the said Invention, and so far there
is nothing meant to be described as new in the construction of the said
furnace boiler piece, except its application, use, and mode of applying or
attaching the same to these improved constructious of main boilers.
The improvements in furnaces under this Invention have for their object
the still further or more perfect commingling and ignition of the gaseous
products of combustion arising from the fuel in such and other constructions
of furnaces than is possible by the means just described, and consists in,
making very close air-tight furnace doors hinged to a hollow furnace mouth
all round over the doors, perforated in front with small holes capable of being
opened and shut by a sliding plate. The two lower ends of the hollow mouth
lead direct into two side divisions formed in a bollow "dumb" plate, equal to
one-fourth each of the width of the whole furnace. The furnace bars of the
furnace being hollow those at the sides conduct the cold air led into them
from the hollow furnace mouth and side divisions of the "dumb" plate down
to the flame bridge, which supports the back open end of the bars, and the
bridge being also hollow conducts the air which was partially heated in
passing back down the two side sets of furnace bars into the centre range or
half of the furnace bars, which conducts and thoroughly heats the air as it is
led forward through them to the centre hollow division in the "dumb" plate,
where it escapes out through perforations in the upper side of the "dumb"
plate into the front end of the furnace, over a screen or guard plate to
prevent the fuel from stopping up the holes, where it is carried forward by.
the draught so hot that it is ready to ignite, and assists the dense cold gases;
rising off the fuel in front of the furnace to combine and ignite as they are
evolved, without causing the production and escape. of smoke which cannot be
utilized. This arrangement applied to the furnaces of both flues of the
furnace part of the boiler, and charged alternately as before described, will
make a most economical and efficient steam boiler and non smoke-producing
furnace, embodying one modification of the improvements contained in this;
Invention.

page_text: These improvements for heating the air in furnaces, though described as
applied to a modification of the improvements herein described in the con-
struction of steam boilers, are also applicable to nearly all constructions of
furnaces for steam and heat generating purposes generally.
The combined objects and advantages to be obtained from these improve-
ments in the construction of steam boilers are, great simplicity with greater
heating surface, and more suitability for all sizes of boilers, with greater and
simpler means of regulating the circulation of the water for the prevention of
"priming" or irregular ebullition than in steam boilers as heretofore con-
structed. And the advantages to be obtained from these improvements in the
construction of furnaces are, a greater and more perfect power of combustion
of coal or other fuel without the production or escape of unutilized or un-
consumed smoke in proportion to the size of grate and furnace than heretofore,
and consequently a greater saving or economy of fuel, time, and money by the
use of the whole Invention than has heretofore been obtained in the use of
such.eam boilers and furnaces.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Sinclair in the Great Seal Patent Office on the
10th January 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
SINCLAIR, of Leith, in the County of Edinburgh, North Britain, Boiler Maker,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of July, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
George Sinclair, Her special licence that I, the said George Sinclair, my
executors, administrators, and assigns, or such others as I, the said George
Sinclair, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN STEAM BOILERS AND
FURNACES," upon the condition (amongst others) that I, the said George
Sinclair, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly describe

page_text: and ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said George Sinclair, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
This boiler is constructed with two semicircular parts placed one above the
other, connected together by vertical tubes. The front part however, that is
to say, the whole length of the furnace or fire-box part is of a cylindrical form
wherein I construct one or two round furnaces, such front part being attached
to the main part by two round or oval tubes, one at the top and the other at
the bottom; I also adopt and use two large tubes placed at the back end
of the boiler for the purpose of causing a circulation of the water in the
boiler.
In order that my Invention may be readily understood I have accompanied
these Presents by illustrative Drawings, which I will now describe.
DESCRIPTION OF THE DRAWINGS AND OF THE INVENTION THEREBY
ILLUSTRATED.
Fig. 1, longitudinal section of a boiler constructed in accordance with my
said Invention; Fig. 2, section taken at C, D, (Fig. 1); Fig. 3, plan view;
Fig. 4, section taken at A, B, (Fig. 1). In these Figs. E, F, and G are
marked on and denote the circulating passages.
Fig. 5, transverse section taken at A, B, (Fig. 6), the said Fig. being an
elevational, and Fig. 7 plan view. In these Figs. a deuotes the upper semi-
circular part of the boiler, and the lower semicircular part; c, the vertical
tubes (some only being marked) connecting the two semicircular parts; d, the
circulating passage at the back end of the boiler, shewn at Fig. 5 by the
dotted ovals.
Fig 8, partial section of a boiler, shewing furnace bars and bridge. A,
hollow bridge, having an opening (denoted by >) into the ash-pit, the
same communicating with the hollow bar B, which at the part or dead plate C
opens at the point D into the front of the furnace.
Fig. 9, plan view of Fig. 8. The same letters of reference apply here as
have been just described with reference to Fig. 8.
Fig. 10, longitudinal section of a Cornish boiler, with vertical tubes
connected with and opening into the main part of the boiler; Fig. 11, plan;

page_text: Fig. 12 section on line A, B, at Fig. 10; Fig. 13, section at line C, D,
(Fig. 10). In these Figs: G denotes the circulating passage; c, the vertical
'tubes (some only marked).
In all the Drawings above described the main portion of the boiler is
'marked M, and N denotes the fire-box.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed; I hereby, declare
that I claim with regard to the arrangement and construction of the boiler
shewn in the Drawings the two semicircular parts connected by vertical tubes.
And I also claim the circulating tube or tubes, passage or passages, at the
back end of the boiler, as shewn in the said Drawings (in small boilers. of this
description, however, I attach no fire-box, as shewn in the Drawings, but
I place the fire underneath the boiler, or 'in a brick furnace in front of the
boiler).
The circulating tube or tubes, passage or passages, shewn in the said
Drawings I also claim as applied to the common Cornish boilers and to. multi-
tubular boilers with vertical or longitudinal tubes."
I also claim the peculiar manner by which the smoke is consumed in this
boiler, that is, by the air passing into an air chamber at back end of furnace
bars, and thence through. hollow furnace bars into a hollow dead plate passing
out as shewn in the Drawings over the top of the fire, the hot air thus '
consuming the smoke as it rises from the fire or fires.
In witness, whereof I, the said George Sinclair, have hereunto set my
hand and seal, this Seventh day of January, in the year of our Lord
One thousand eight hundred and sixty-eight.
Witness,
R. FULLERTON.
GEORGE SINCLAIR. (L.S.)