IMPROVED MEANS, APPARATUS, AND FURNACES FOR GENERATING STEAM WITH ECONOMY IN FUEL
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by William Tongue at the Office
of the Commissioners of Patents, with his Petition, on the 24th
July 1869.
I, WILLIAM TONGUE, of Brixton, in the County of Surrey, Engineer,
do hereby declare the nature of the said Invention for "IMPROVED MEANS,
APPARATUS, AND FURNACES FOR GENERATING STEAM WITH ECONOMY IN FUEL," to
be as follows:-
Hitherto when burning fuel for the purpose of generating steam the
products of such combustion have been at once carried away at the
ordinary pressure of the atmosphere with greater or less rapidity from
the furnace through the flues in or around the steam generator to the
chimney or up-take. And it is well known that when generating steam
by the methods hitherto practised there is a very considerable waste of
fuel, much of the heat developed by the combustion of the fuel passing
away by the chimney both in an active and latent form.
Now according to my Invention I carry on the combustion of the
fuel in the furnace at a higher atmospheric pressure than the ordinary
pressure of the atmosphere, and I also cause the products of combustion
to travel from the furnaces through the flues in or around the steam

page_text: generator at a higher pressure than the ordinary pressure of the atmo-
sphere; and after the products of combustion have circulated over a
suitable area of heating surface I allow them to escape either through
a weighted valve or through an aperture of suitable dimensions, to
maintain the desired pressure within the furnaces and flues, and I so
construct and arrange the furnaces and flues as to resist the expansive
force of the compressed air or gases within them.
In carrying my Invention into practice I provide suitable means for
closing the ordinary fire-doors. of the furnace, and I so arrange the
furnace that it can be supplied with fuel through suitable apertures
without any injurious escape of the compressed gases from the furnace.
The grate bars may be arranged in an endless chain or otherwise, so as
to carry a continuous supply of fuel through the furnace; or the furnaces
may be provided with suitable flues, apertures, and valves, so that they
may be opened from time to time and charged by hand. Such furnaces
may also be so arranged as to be charged alternately. The furnace or
furnaces may be lined with fire-brick or clay or other refractory material,
and they may also be arranged in suitable combustion chambers exterior
to the boiler, surrounded or strengthened with metal, so as to resist the
internal pressure. At any parts or apertures where there may be a
tendency of the compressed gases within the furnaces, to escape jets
or currents of air or steam of greater pressure than that of the air or
gases within the furnace may be employed to counteract the tendency to
escape, I close the exit from the flues by a damper or valve, which can be
removed when lighting the fires or supplying the fuel, or separate flues
may be provided from the furnace for this purpose, which can be closed
by a damper or valve when the furnace is in operation. I employ any of
the appliances hitherto used for compressing the air, and I inject and
distribute the air into the furnaces through suitably arranged apertures,
which will vary in form and arrangement according to the construction
of the furnaces employed; and steam may be employed for the support
of combustion, mixed with the air or alone, and either solid, liquid, or
gaseous matters, alone or combined with one another; may be employed
for the purpose of combustion within the furnace.