Improvements in or connected with the Furnaces of Steam Boilers.
Year: 1892

page_text: Date of Application, 29th Sept., 1892
Complete Specification Left, 29th July, 1893—Accepted, 16th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in or connected with the Furnaces of Steam Boilers.
I, WILLIAM THOMAS SMITH, of 89 George Arthur Street, Bolton-le-Moors,
in the County of Lancaster, Foreman Fitter, do hereby declare the nature of this
invention to be as follows:-
This invention relates to internally fired boilers and is designed with the object
of more effectually consuming or preventing smoke and the more efficient generation
of steam.
It consists essentially in placing a casing or lining of fire brick or similar
material inside the crown of the furnace tube with one two or more water tubes or
pipes connected at each end with the water space of the boiler the casing and
water tubes being situated with a space between them and the plates of the furnace
tube.
In carrying out the invention a casing of fire brick or other material (in the case
of fire brick of about 2 inches or thereabouts in thickness) is placed inside the
furnace tube. The casing extends from the front of the furnace tube immediately
over the furnace, back to the end of the furnace beyond the fire bars ending pre-
ferably over the bridge of the furnace. A space of an inch or so is left between
the casing and the top and sides of the furnace tube. One two or more water tubes
of about 24 inch bore are fixed to the furnace and connected by elbow, tee or other
joint with the water space of the boiler.
Two of these water tubes are preferably employed one at each side of the arched
casing and the fire-bricks which comprise it resting thereon. At the back or
further end of the furnace these water tubes are fixed or attached by an elbow
joint secured on the inner side by hollow nuts and at the front by a tee joint thereby
connecting the tubes with the inside of the boiler. The front end of the tee joint
is protected or covered by a cap or plug which can be removed to clean or inspect
the tube. The water tubes are preferably set at a slight incline say about 5 inches
above the bars at the back or further end of the furnace and about 9 inches from
the front with a space of about an inch or so between them and the sides of the
furnace tube.
Instead of two water tubes placed at the sides of the furnace a single tube may
be used placed in the centre of the furnace inclined from the front towards the back.
This tube may be placed below the casing or if desired may form part of the casing
the fire bricks abutting against it at both sides.
The casing may be formed of an arch of fire-bricks of ordinary size or in short
lengths or segments to suit either the side tube or single central tube arrangement,
or it may be made in suitable blocks to complete the arch or segment of circle
required.
The fire brick may if desired be perforated throughout or at intervals part of
the casing being perforated and part without perforations. The fire bricks also
may be prepared to stand intense heat by being made with strong iron netting or
lengths of metal may be placed inside the blocks during manufacture forming part
of same.
A pad of asbestos can be used to protect the water tubes from contact with the
fire bricks the asbestos pads being placed in recesses formed in the bricks.
Dated this 28th day of September 1892.
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in or connected with the Furnaces of Steam Boilers.
I, WILLIAM THOMAS SMITH, of 89 George Arthur Street, Bolton-le-Moors,
in the County of Lancaster, Foreman Fitter, 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 :-
This invention relates to internally fired boilers and is designed with the object
of more effectually consuming or preventing smoke and the more efficient generation
of steam.
It consists essentially in placing a casing arch or lining of fire brick or similar
material inside the crown of the furnace tube resting upon water tubes or pipes
connected at each end with the water space of the boiler the casing and water tubes
being situated with a space between them and the plates of the furnace tube.
The invention will be fully described with reference to the accompanying
drawings in which several methods are shown of connecting the steel water tubes
which support the firebrick arch with the water space of the boiler.
Fig. 1. Sectional elevation.
Fig. 2. Front elevation of same.
Fig. 3. Front elevation of single flue with modified arrangement for connecting
the water tubes.
Fig. 4. Front elevation of flue showing another modification.
Fig. 5. Sectional elevation showing another modification.
Fig. 6. Front elevation showing another method of connecting the water tubes.
Fig. 7. Sectional elevation of same.
Fig. 8. Sectional plan of one flue of same.
Fig. 9. Plan view of further modification.
The boiler A and the furnace tube B are of any ordinary or suitable
construction.
Inside the furnace tube B directly over the furnace and extending down the
sides thereof I place a casing C of fire brick, fire clay or other refractory material
capable of resisting a high degree of heat. I prefer to use fire bricks or tiles c
about 2 inches or thereabouts in thickness.
The casing C extends from the front of the furnace tube B inside the crown of
the furnace back to the other end of the furnace beyond the fire bars D ending
preferably over the bridge E of the furnace. Between the casing C and the plates b
forming the top and sides of the furnace tube B I provide a space of about an inch
so that the bricks c do not touch the plates b. This allows the casing C to become
intensely hot the heat from which radiates both upwards and downwards the intense
heat radiated in the under side increasing the temperature of the products of com-
bustion as they rise from the fuel and promoting the complete combustion of all
unconsumed carbon.
At each side of the furnace there is fixed a water tube F (of about 2 to 3 inch
bore) which supports the casing C the ends of the tiles or bricks resting thereon
and also serves to increase the heating capacity of the boiler and to assist the
circulation of the water therein.
These water tubes F are preferably made of steel and are fixed so that both ends
are in communication with the water space of the boiler and may be arranged in
several ways as shown in the drawings. The water tubes F are preferably set at a
slight incline say about 5 inches above the bars at the back or further end of the
furnace and about 9 inches from the front with a space of about an inch or so
between them and the sides of the furnace tube.
In Figs. 1 and 2 the tubes F are shown attached at the back or the further end
of the furnace by an elbow joint secured on the inner side by hollow nuts and at the
front by a tee joint thereby connecting the tubes with the inside of the boiler. The

page_text: front end of the tee joint is protected or covered by a cap or plug which can be
removed to clean or inspect the tube.
In Fig. 3 the tubes F are attached separately to the boiler plates b at the back
and coupled together at front and connected to the crown of the boiler at f.
In Fig. 4 the tubes F are separately attached to the boiler plates
front and coupled together at the back and connected to the bottom of the
boiler at f
at the
In Fig. 5 the tubes F may be coupled together both front and back of the
furnace one connection serving for the two in the crown at f and in the bottom
at f¹.
In Figs. 6, 7, and 8 to obviate the necessity of drilling the furnace tube plates b
both ends of the tubes F are connected to the boiler front plate G at g and othe
water circulating from g¹ through the tubes F round the furnace to g. In this case
the tubes may be placed horizontal the back ends being supported on the bridge E
or on a bracket provided for the purpose.
In Fig. 9 the water tube F is connected to the boiler with a single connection
being provided with an inner tube for circulation of water.
The casing or arch C in the crown of the furnace may be constructed of fire clay,
gannister, silica or mixtures of asbestos or other refractory material made in suitable
segments bricks tiles or blocks c extending the whole or part length of the furnace.
These segments c may if desired be perforated throughout or at intervals part of
the casing being perforated and part without perforations.
A pad of asbestos may be used to protect the water tubes from contact with
the segments or bricks c the asbestos pads being placed in recesses formed in the
bricks.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A steam boiler furnace provided with a casing or arch of fire clay or other
refractory material placed in the crown of the furnace with a space between it and
the furnace tube plates and extending the whole or part length of the furnace
substantially as described.
2. The combination with a steam boiler furnace B of an arched lining or casing C
of fire bricks c or other refractory material provided with a space between it and
the furnace plates b, and water tubes F placed down each side of the furnace by
which the casing is supported substantially as described.
Dated this 97th dow of July 1893
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.