IMPROVE- MENTS IN APPARATUS FOR GENERATING HEAT IN STEAM BOILERS AND FURNACES
Year: 1873

page_text: LETTERS PATENT to William. Smith, of Newcastle-on-Tyne, in the
County of Northumberland, Engineer, for the Invention of "IMPROVE-
MENTS IN APPARATUS FOR GENERATING HEAT IN STEAM BOILERS AND
FURNACES."
Sealed the 20th February 1874, and dated the 22nd August 1873.
PROVISIONAL SPECIFICATION left by the said William Smith at the
Office of the Commissioners of Patents, with his Petition, on the
22nd August 1878.
I, WILLIAM SMITH, of Newcastle-on-Tyne, in the County of North-
umberland, Engineer, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN APPARATUS FOR GENERATING HEAT IN STEAM BOILERS
AND FURNACES," to be as follows :—
This Invention relates to furnaces used for generating heat either for
'steam boilers or other-purposes, in which the air necessary for combustion
of the fuel in such furnaces is forced in under pressure by closing up the
mouth of the furnace and ash-pit with air-tight doors and feeding the
fires through air-tight hoppers and forcing air through the sides of the
furnace, and thus burning the fuel under pressure,

page_text: My improvements have for their objects greater facilities for inspecting,
controlling, and clearing the fires and ash-pits of such furnaces, and
consist in enclosing the whole of the boilers and furnaces, or the
furnaces, or the front part containing the furnaces, together with any
required quantity of fuel, and the firemen with their tools, the gauges,
cocks, and other fittings within an air-tight compartment or compart-
ments of suitable strength and of sufficient size to allow the firing and
other operations to be carried on in the usual manner, either with or
without self-acting feeding, stoking, and other appliances. Into such
air-tight compartment or compartments I force by fans, pumps, or other
suitable means air of any required volume and pressure; I thus obtain
all the advantages of combustion of fuel under pressure, and at the same
time the furnaces and ash-pits, and all the necessary operations con-
nected with them, are under as completo control and arc inspected as
readily as if in the open air. The pressure within the air-tight compart-
ment and the emission of the products of combustion at any required
pressure can be regulated by one or more adjustable valves or dampers
in the uptake or chimney, and the hot gases may be circulated through
one or more series of tubes to abstract all their available heat. The spent
gases I sometimes employ (either dry or moistened by jets of water or
steam) to work the blast or air pumping engine, which may be fitted
with an auxiliary steam cylinder capable itself of doing the required

page_text: make air-tight the firing space between the boiler fronts and the adjacent
bulkheads, and also the coal bunkers and uptakes.
For Cornish or other land boilers, and for furnaces generally, I form
an air-tight firing compartment, as described, with a sufficient supply of
fuel fed into it through air-tight hoppers or by other suitable means.
I prefer to cover all parts of boilers within the air-tight compartment,
and especially those facing the firemen, in all cases to which my Inven-
tion is applied (marine boilers in particular) with a thick coating of
some non-conducting substance, leaving a spaco between such covering
and the ordinary casing or "cleading" through which the air is made to
pass from the firing compartment into the furnaces.
I prefer to fit the ash-pit and fire-place of furnaces constructed
according to my Invention with the separate usual doors but fitted with
light adjustable metal or other flaps or valves, opening inwards, so that
the pressure without shall somewhat exceed that within.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Smith in the Great Seal Patent Office
on the 21st February 1874..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
SMITH, of Newcastle-on-Tync, in the County of Northumberland,
Engineer,' send greeting.
:
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of August, in the year of our
Lord One thousand eight hundred and seventy-threc, in the thirty-seventli
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Smith, Her special licence that I,
the said William Smith, my executors, administrators, and assigns, or
such others as I, the said William Smith, 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 Ircland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN APPARATUS FOR

page_text: GENERATING HEAT IN STEAM BOILERS AND FURNACES," upon the condition
(amongst others) that I, the said William Smith, my executors or
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe 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 William Smith, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement and accompanying Drawing (that is to say) :-
My Invention relates to furnaces used for generating heat either in
steam boilers or for other purposes, in which the air supplied for effecting
the combustion of the fuel is forced in under a pressure greater than the
ordinary atmospheric pressure by closing the mouth of the furnace and
the ash-pit with air-tight doors, and feeding the fuel to the fires through
air-tight hoppers, and forcing the air into the furnaces by means of
pumps or other suitable apparatus, and thus burning the fuel undor
pressure.
My improvements have for their objects greater facilities for inspecting,
controlling, and clearing the fires and ash-pits of such furnaces than in
the methods heretofore adopted of burning fuel in furnaces under pres-.
sure, and they consist in enclosing the whole of the boilers and furnaces,
or the furnaces only, or the front part containing the furnaces, within an
air-tight chamber or compartment or compartments sufficiently large to
contain any required quantity of fuel, as well as the firemen with their
tools, and the guages, cocks, and other fittings to which it is necessary
that the firemen should have access, and I make such chamber, or com-
partment or compartments, of sufficient strength to resist the internal
pressure of air which I force into it, of any required volume and pres-
sure, by pumps, fans, or other suitable means and appliances. I make
the chamber, or compartment or compartments described sufficiently
large to allow the firing and other operations of the firemen to be carried
on in the usual manner, either with or without self-acting, feeding,
stoking, and other apparatus of the kinds used with boilers constructed
in the methods ordinarily used and practised.

page_text: By the methods described I obtain all the advantages of combustion
of fuel under pressure, and at the same time the furnaces, ash-pits, and
other appliances connected with the furnaces and boilers, and all the
necessary operations connected with them are under as complete control,
and are as readily inspected as if in the open air.
I regulate the pressure within each air-tight chamber or compartment,
and the emission of the products of combustion at any required pressure,
by means of one or more adjustable valves or dampers in the uptake or
chimney of the furnace, or by adjustable dampers or valves applied to
the tubes from which (where steam boilers are being used) the products
of combustion pass to the chimney or uptake, or by these methods
combined. The heated gases and the products of combustion may be
circulated through one or more tubes or series of tubes, and through
apparatus of the kinds ordinarily constructed and used for superheating
the steam and heating, the feed water, so as to abstract, as far as possible,
their remaining available heat.
I sometimes employ the spent gases and heated air (either dry or
moistened by jets of steam or water introduced into them) in order to
work the blast engine or air pumping engine by which the air is supplied
to the chamber or compartments, and such engine may also be fitted
with an auxiliary steam cylinder capable itself of doing the required
work when desired.
Where the steam pipes, feed water pipes, guage and other pipes, or
the chimney, pass through the sides of the chamber or compartment, I
make them pass through expansion joints or other suitable air-tight
joints. It is necessary-to make provision in order to allow the firemen,
when necessary, to enter or leave the chamber or compartments without
the pressure within the latter becoming materially reduced, and for this
purpose I provide cach such chamber or compartment with a revolving
hollow door, air-tight or nearly so, having one entrance, and capable of
being worked from within by means of suitable gearing, so that the
entrance may be made to communicate either with the interior or the
exterior of the chamber. Or I close the chamber or compartment with
tivo doors having a space between them and opening inwards, and made
air-tight when closed by means of india-rubber or other suitable material,
and I make the inner one of such doors with one or more adjustable air

page_text: apertures or slides, and I construct and arrange the doors so that one
must be shut before the other is opened.
Where my Invention is applied to the furnaces used in steam vessels
I make air-tight the entire space between the skin of the ship, the deck,
and the two bulkheads which form the boiler room, or the boiler and
engine room, and I close the hatches of the coal bunkers and of other
openings into the space so enclosed with doors lined with india-rubber or
other suitable material by which they can be made air-tight or nearly so.
Or I make air-tight the firing space enclosed between the boiler front
and the adjacent bulkhead, and also the coal bunkers and uptakes. I
discharge the ashes and other refuse from the furnaces into the sea
through a tube or passage, the upper end of which is fitted with a
suitable hopper, and is sufficiently, above the water line, whilst its lower
end passes through the ship's side at any convenient point either above or
below the water line.
Where my Invention is applied to the furnaces of Cornish or other
land boilers, or to furnaces of any other kind, I form an air-tight
chamber or firing compartment enclosing the mouth of such furnaces'in
the method already described, and of sufficient size to hold a supply of
fuel for consumption during one day or other convenient period, or fitted
with air-tight hoppers or other suitable apparatus by which a supply of
fuel may be introduced as required.
ענת
Where Invention is used I prefer to cover all parts of the boilers
within the air-tight chamber or compartments, and especially those parts
which face the firemen (particularly in marine boilers) with a sufficiently
thick coating of some non-conducting substance, leaving a space between
such covering and the ordinary casing or "cleading" of the boiler,
through which space the air is made to pass from the chamber or com-
partment into the furnace; and I prefer to fit the ash-pit and fire-place
of furnaces constructed according to my Invention with separate doors,
which doors I fit with light adjustable flaps or valves of metal or other
suitable material opening.inwards, so that the pressure without shall
somewhat exceed that within.
Where my Invention is applied to the furnaces of boilers I prefer to
fit to the shells of such boilers tubular hollow stays instead of the
ordinary solid stays used for strengthening the boilers, and I arrange
these hollow stays so that the products of combustion pass through them

page_text: on their way to the uptake or chimney, and their temperature is thus
advantageously reduced. Or sometimes such tubes may be combined
with the ordinary solid stays. I sometimes place strong glass windows
in the air-tight chamber and between the engine and boiler room.
The accompanying Drawing is in illustration of my Invention, and
represents a longitudinal section of a marine boiler.
a is the framework forming the bottom of a ship; b, b¹, are air-tight
bulkheads forming a chamber c, enclosing within it the boiler d. Air is
forced into the chamber c by the fan e driven from the engine shaft ƒ.
The air-tight doors g, as described, allow entrance to and egress from the
chamber c. The chimney is surrounded by the air casing i, which
passes through the top of the chamber c; kis the steam superheating
apparatus, and 7 is a light door opening inwards as described; m, m, m,
are transverse tubular stays to the boiler, and n, n, n, are solid stays.
The dotted lines at o represent the air pressure regulating valve as
already described.
Having now described my Invention, and the manner in which it is to
be performed, I do not claim the use of air supplied under pressure to
furnaces, but I claim the construction and arrangement of air-tight
chambers and compartments supplied with air under pressure, and
sufficiently large to contain the firemen with their tools, appliances, and
fuel, and the feeding and regulating the furnaces from within such
air-tight chambers and compartments, substantially as described and
shewn in the Drawing.
In witness whercof, I, the said William Smith, have hercunto
set my hand and seal, this, Twentieth day of February, in the
year of our Lord One thousand eight hundred and seventy-
four.