Improvements in Apparatus for Supplying Air to Steam Boiler or other Furnaces.
Year: 1889

page_text: Date of Application, 22nd Jan., 1889
Complete Specification Left, 22nd Oct., 1889-Accepted; 23rd Nov., 1889
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Supplying Air to Steam Boiler or
other Furnaces.
I, NICHOLAS SWANSON HAWKS of Eden Holme, Atherton Road, Forest Gate,
Essex, Engineer, do hereby declare the nature of this invention to be as follows:-
The object of my invention is to supply air to furnaces in a heated state, the heat
being obtained by causing the air before its admission to the furnace to take up some
of the waste heat of the furnace. The invention mainly consists in the combination
with an air exhauster or fan in the base of the funnel or uptake whereby an induced
draft is produced, of passages through which the air is drawn and in which it becomes
heated by contact with hot surfaces before entering the fire. In applying my inven-
tion for example to a steam boiler fitted with horizontal smoke tubes I form divisions
or passages for air in the smoke box and for this purpose I fix directly opposite the
main tubo plate an additional tube plate and at some distance therefrom a division
plate and beyond that a third plate so that air which is admitted at the bottom of the
smoke box between the division plate and the plate beyond and is drawn by the
exhauster or fan in the base of the funnel or uptake will pass up between these plates
and then down between the division plate and the first described additional plate.
Between the additional plates I place lengths of iron or copper tubes forming con-
tinuations of the ordinary smoke tubes, so that the smoke and products of combustion
in passing through these additional lengths of tubes will heat the air which passes
over them as already described. The first named additional tube plate also serves as
a protection to the surface of the main tubo plate which would otherwise be exposed
to lower temperature. The admission of the air is controlled by a sliding door.
In passing up and down the passages in the smoke box the air is heated by what
would otherwise bo wasto heat and it is then conducted to the furnaces, being
preferably admitted below the fire bars.
One great advantage of my arrangement is that in case the apparatus for producing
the induced draft should get out of order the furnace will work with ordinary draft
by simply opening a damper to the ash pit; this is not the case with furnaces working
with forced draft as hitherto arranged, because these can scarcely work at all if the
forcing arrangements become deranged.
Instead of placing the fan or draft producer in the funnel as described it can be
placed in any other convenient position, such for example as the stoke hole.
Dated this 22nd day of January 1889.
J. C. MEWBURN,
55 & 56. Chancery Lane, London. Patent Agent.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Supplying Air to Steam Boiler or
other Furnaces.
I, NICHOLAS SWANSON HAWKS of Eden Holme, Atherton Road, Forest Gate,
Essex, Engineer, do hereby declaro the nature of this invention and in what manner
the same is to be performed, to he particularly described and ascertained in and by
the following statement :—
The object of my invention is to supply air to furnaces in a heated state, the heat

page_text: being obtained by causing the air before its admission to the furnace to take up some
of the waste heat of the furnace. The improvements relate to apparatus of the kind
in which a fan, exhauster or blower is employed to cause a draught, either induced or
forced, of the air through passages in which it becomes heated by contact with hot
surfaces before entering the fire, and the invention has special reference to steam
boiler furnaces which are connected with horizontal smoke or fire tubos passing
through the body of the boiler.
According to my invention I form divisions or passages for air in the smoke box
and for this purpose I fix directly opposite the main tube plate an additional tube
plate, and at some distance therefrom another tube plate, and in cases where the cold
air is admitted at the bottom of the smoke box to the space enclosed between these
tubo plates I add an intermediate division plate. When this division plate is
employed the air enters from below into the space between the division plate and the
plate furthest from the main tube plate, and being induced or forced by the action of
the fan, passes up between these plates and then down between the division plate and
the plate next the main tube plate. Between the various plates I fit lengths of iron
or copper tubes forming continuations of the ordinary smoke or fire tubes so that the
smoke and products of combustion in passing through these additional lengths of
tubes will heat the air which passes over them as already described. The additional
tube plate which is next the main tube plate also serves as a protection to the surface
of the latter which would otherwise be exposed to lower temperature. When the air
to be heated enters the space between the plates at the top the intermediate or division
plate can be dispensed with.
In passing through the passages or space formed in the smoke box by the additional
plates above described the air is heated by what would otherwise be wasto heat, and
it is then conducted to the furnaces, being preferably admitted below the firo-bars.
The fan for producing the necessary draught can be placed either in a position
where it will create an induced draught, as in the base of the funnel or uptake, or
where it will create a forced draught, as in the stokehold or other part.
The accompanying drawings will serve to illustrate my invention. They represent
an arrangement in which the fan is placed on the top of the boiler, but it may be
placed in any other convenient position.
a a are the furnaces or fire-places-6 the boiler, c c the smoke or fire tubes, d the
inner main tubo plate and e the outer main tube plate. f is an additional plate fixed
in the smoke box g directly opposite the tube plate e. his another tube plate at
some distance from the plate f. The space between the plates f and his enclosed at
top and bottom except where the air inlet and outlet pipes are connected thereto, and
it has horizontal plates as shown in broken lines forming a zig-zag passage in same.
ii are tubes forming continuations of the tubes c c, and through which the smoke and
products of combustion pass on their way from the tubes c c to the funnel k. is the
fan.
m is an air pipe by which the air forced by the fan is conducted to the space
between the plates fand h, there being a separate branch pipe p to this space in each
furnace. nn are pipes by which the air heated in the said spaces is conducted to the
furnaces or fire-places; the pipes n n are shown as admitting the heated air below the
fire bars, which is what I prefer, but they can, if desired, be arranged to deliver it at
any other part or parts. When the air to be heated is admitted to the space between
the plates and at the bottom (at the arrow q) as is the preferred arrangement
when the fan is fitted in the funnel k so as to create an induced draught, a vertical
division plate should be fitted in the said space with an opening at top so that the air
after passing up at one side of the division plate may pass down the other side and
then enter the pipe n leading to the furnaces. In each hot air pipe n it is preferred to
fit a butterfly valve connected with the furnace doors by mechanism indicated at t
in such manner that when the fire door is opened the valver closes or throttles the
pipe n.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The apparatus constructed substantially as hereinbefore described and represented
in the accompanying drawings for supplying air to steam boiler and other furnaces.
Dated this 22nd day of October 1889
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent Agent.