Improvements in or appertaining to Steam-boiler Furnaces and Flues, Adapted for Obtaining More Perfect Combustion and Controlling the Supply of Air.
Year: 1890

page_text: Date of Application, 11th Jan., 1890
Complete Specification Left, 11th Oct., 1890-Accepted, 15th Nov., 1890
PROVISIONAL SPECIFICATION.
Improvements in or appertaining to Steam-boiler Furnaces and
Flues, Adapted for Obtaining More Perfect Combustion and
Controlling the Supply of Air.
I, GEORGE LAWSON Engineer of the s.s. Bona Vista now lying in the Brunswick
Dock, Liverpool, in the County of Lancaster, do hereby declare the nature of this
invention to be as follows:-
The object of the invention is to provide a steam boiler furnace or flue adapted for
obtaining a more perfect combustion of fuel, and for controlling the supply of air
thereto.
It is well known that fuel employed in furnaces does not undergo complete com-
bustion on account of the insufficient supply of oxygen, and it is sometimes difficult
to obtain by the means hitherto employed sufficient draught to keep up the required
pressure of steam. This I have found more particularly to be the case with marine
boilers during calms, when it is often most difficult to retain the normal pressure of
steam in the boiler owing to the draught being insufficient to maintain the proper
combustion of fuel.
Now according to my invention, I propose to completely close the end of each flue,
leaving however an orifice of suitable width and length in the closing plate, preferably
just below the fire bars. Through this orifice or in other suitable manner I arrange
a device for delivering a jet or jets of steam into the furnace below the fire bars.
The device may comprise for example a pipe placed transversely with a number of
perforations through which jets of steam can issue. A door adapted to close tightly
is preferably provided to clear out the ash pit.
The mode of action is as follows:-
The steam jets draw a continuous current of air through the orifice aforesaid. The
air enters the hot ash pit and mixes with the steam, whereby it is heated. It then
passes through the grate and through the fuel when it is beated to the same tempera-
ture as the furnace and ensures the proper combustion of the fuel and of the gases
and smoke. In many boilers, cold air is admitted above the fire which does not
properly mingle with and consume the gases, owing to the fact that it does not attain
the same temperature as the furnace.
The air supply is regulated by increasing or decreasing the volume of steam
admitted by the jets.
Tinted this 10th day of Louvory 1900
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or appertaining to Steam-boiler Furnaces and
Flues, Adapted for Obtaining More Perfect Combustion and
Controlling the Supply of Air.
I, GEORGE LAWSON, Engineer of the s.s. Bona Vista, now lying in the Brunswick
Dock, Liverpool in the County of Lancaster, 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 :-
The object of the invention is to provide a steam boiler furnace or flue adapted for
obtaining a more perfect combustion of fuel, and for controlling the supply of air
thereto.
It is well known that fuel employed in furnaces does not undergo complete

page_text: combustion on account of the insufficient supply of oxygen, and it is sometimes difficult
to obtain, by the means hitherto employed; sufficient draught to keep up the required
pressure of steam. This I have found more particularly to be the case with marine
boilers during calms, when it is often most difficult to retain the normal pressure of
steam in the boiler owing to the draught being insufficient to maintain the proper
combustion of fuel.
Now according to my invention, I completely close the front end of the boiler flue or
flues, leaving however an entrance of suitable shape and area in the closing plate,
preferably just below the fire bars, through which a jet or jets of steam are passed
into the flue.
The accompanying drawings illustrate, as an example, an end elevation of a marine
boiler.
In this drawing,
A, is the main steam supply from superheater, B branch steam pipes to furnaces,
C perforated jet pipes blowing steam into ash pit immediately under the fire bars,
D openings of suitable shape and area in the plates d which close the front ends of
boiler flues, the said openings admitting the entrance of steam from the perforated jet
pipes C, and of air which passes between and also by preference above and below the
said pipes. E is an ashpit door, which is provided with fastenings, and is adapted
to close tightly. Suitable valves are provided for shutting off or regulating the
steam.
The mode of action is as follows:-
The steam jets draw a continuous current of air through the orifice D aforesaid.
The air enters the hot ashpit and mixes with the steam, whereby it is heated. It
then passes through the grate, and through the burning fuel, where it is heated to the
same temperature as the furnace, and ensures proper combustion of the fuel, and
prevents, entirely or to a very great extent, the emission of smoke, which, in most
furnaces, has hitherto been allowed to pass away unconsumed. In many boilers, cold
air has hitherto been admitted above the fire which does not properly mingle with
and consume the furnace gases, owing to the fact that it does not attain the same
temperature as the furnace, whereas, by my invention, the air is heated before
entering the furnace, first, by mixing with the steam, then by the heat of the ashpit,
and, finally, by contact with the grate and burning fuel.
The air supply is regulated by increasing or decreasing the volume of steam
admitted by the jets.
.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, 1 declare that what
I claim is :-
In combination with a steam boiler furnace flue, a plate such as d closing the front
end of said flue and having an opening such as D below the level of the fire bars, and
one or more perforated pipes, such as C), located in proximity to said opening, and
adapted to deliver steam through the same into the furnace, the said pipe or pipes
being so arranged as to permit the air to be drawn past them and through the
opening by the force of the jets, substantially as described.
Dated this 10th day of October 1890.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.