Year: 1887

page_text: Date of Application, 10.h Dec., 1887
Complete Specification Left, 8th Sept., 1888
Complete Specification Accepted, 12th Oct., 1888
I, THOMAS LISHMAN, of 2 Close, Newcastle-on-Tyne, in the County of Northumber-
land, Engineer, do hereby declare the nature of this invention to be as follows :-
-
This invention relates to improvements in and applicable to steam boilers, the
object being to provide means for effecting a more perfect combustion of the fuel
and gases, heating of the feed water, circulation of the water, and smoke prevention.
In carrying out my invention I provide a water tube or two or more water tubes
of suitable diameter and length, placed horizontally or vertically inside the flue of a
boiler or boilers, spaces being left between the said tubes.
1 find it advantageous generally to employ four of such tubes which may be
circular, square, or of other form in cross section suitable to the sizes of the boiler.
The tubes are arranged in pairs.
The ends of the tubes are fixed in a tube-plate and the inner ends of each pair
are connected together by a curved tube so that one tube forms an inlet pipe and
The other ends of the said tubes can be
the other an outlet pipe to the boiler.
provided with valves and cocks for connecting them to each other and to the boiler,
in a similar manner to that described in the specification of Letters Patent granted to
me No. 10339, dated 12th of August 1886.
The spaces between the tubes are partially closed in so as to form an air channel
from which air under pressure is forced through the lateral spaces remaining, into
the mass of fuel which is placed and burned on the tube plates of the boiler as in
my said former Letters Patent.
Or, an air tube can be placed in the central space between the water tubes, and
the air be forced out through openings at the sides thereof as will be obvious, the
apparatus being placed inside and on the floor of the furnace.
In some cases instead of connecting the ends of the water tubes by curved tubes
as hereinbefore described 1 place beyond the air-receiver or bridge a water tank in
which the inner ends of the water tubes are secured.

page_text: Into the said air receivers, which I sometimes employ instead of the ordinary
bridges, air is injected from the air channel between the tubes wherein the air becomes
highly heated, and the air is then by means of a diffusing pipe ejected into the
combustion chamber. By this means complete combustion is obtained.
By my invention I can feed the water required for the boiler or other vessel,
through the said water tubes whereby it is heated to a very high temperature before
reaching the boiler.
By connecting the feed inlet tubes by a valve or other means to the lower part and
the outlets to the upper part of the boiler I secure a constant and rapid circulation of
the water in the boiler.
Some of the valves forming connections between the apparatus and the boiler are
automatic or self-acting as a precaution against danger.
The feed water pipes can be attached to a feed water tank suitably arranged for the
purpose.
In the case of marine boilers the water tank can be conveniently placed in the
engine room.
Where two tubes only are used the air passage is conveniently placed under the
tubes.
Dated the 10th day of December 1887.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicant.

page_text: I, THOMAS LISHMAN, of 2 Close, Newcastle-on-Tyne, in the County of Northumber-
land, Engineer, do hereby declare the nature of this invention and in what manner
the same is to be perforined to he particularly described and ascertained in and by
the following statement :-
This invention relates to improvements in and applicable to steam boilers, the object
being to provide means for effecting a more perfect combustion of the fuel and gases,
heating of the feed water, circulation of the water, and smoke prevention, than
hitherto.
In carrying out my invention I provide an apparatus consisting of two or more
water tubes of suitable diameter and length and adapted to be placed horizontally or
vertically inside the flue of a boiler or boilers, spaces being left between the said
tubes.
I find it advantageous generally to employ four of such tubes which may be circular,
square, or of other form in cross section and of dimensions suitable to the size of the
boiler. The tubes are arranged in pairs.
The ends of the tubes are fixed in a tube-plate and the inner ends of each pair are
connected together by a curved tube or by a water tank so that one tube forms an
inlet pipe and the other an outlet pipe to the boiler. The other ends of the said tubes
can be provided with valves and cocks for connecting them to the boiler, in a similar
manner to that described in the Specification of Letters Patent granted to me
No. 10,339, dated 12th of August 1886.
The spaces between the tubes are partially closed in, so as to form an air channel,
from which air under pressure is forced through the lateral spaces remaining, into the
mass of fuel which is placed and burned on the tube-plates of the boiler as in my said
former Letters Patent.
Or, an air tube can be placed in the central space between the water tubes, and the
air be forced out through openings at the sides thereof as will be obvious, the
apparatus being placed inside the furnace.
Air from the air channel between the tubes, in which it becomes highly heated, is
by means of a diffusing pipe or pipes or by other means ejected into the combustion
chamber. By this means complete combustion is obtained.
By my invention I can feed the water required for the boiler or other vessel through
the said water tubes, whereby it is heated to a high temperature before reaching the
boiler.
By connecting one of the tubes or one pair of tubes by a valve or other means to
the lower part and the other tube or tubes to the upper part of the boiler, I secure a
constant and rapid circulation of the water in the boiler.
Some of the valves forming connections between the apparatus and the boiler are
automatic or self-acting as a precaution against danger.

page_text: purpose.
In the case of marine boilers the water tank can be conveniently placed in the
engine room.
In order to enable my invention to be fully understood, I will proceed to describe
how it can be carried into practice by reference to the accompanying drawing, in which
Figure 1 is a front elevation of a steam boiler provided with my improved apparatus
which is here shown as consisting of four water tubes and an air passage arranged
according to my invention, the tubes being shown connected together by a water
tank and the air passage being formed by a centrally placed tube.
Figure 2 is a longitudinal section, and
Figure 3 is a plan partly in horizontal section of the front end of the boiler.
Figure 4 is a transverse section of the apparatus drawn to an enlarged scale.
Figure 5 is a transverse section of part of the furnace tube of a boiler provided with
an apparatus consisting of two water tubes and an air passage formed by closing in
the space between thein.
Similar letters in all the figures indicate similar parts.
Referring to figures 1 to 4
a, a, a, a, are the four water tubes which I provide in the flue of the boiler.
e is the tube-plate in front of the boiler in which the water tubes are fixed and
through which they project as shown. They are here provided with elbows fitted to
pipes & and d communicating respectively through pipes e and e¹ with the feed water
supply and with the feed water inlet to the boiler.
is a stop valve placed in the main feed pipe e, and y is the feed water inlet cock
placed on the boiler at high water level.
his the water tank in the front plate of which the inner ends of the tubes a, a, a¹, a²,
are fitted, the tank thus serving to connect the said ends of the tubes.
i is a pipe which connects the pipe to the boiler, and jis the automatic valve for
pening this connection when the feed pump is not at work.
k is a cock to allow of blowing out the boiler through the apparatus.
a¹
I is the air tube occupying the central space between the water tubes a, a, a¹,
this tube extends from the front of the boiler to a short distance behind the bridge
and is provided on each side with a number of holes m through which air forced in
by a fan blast or other suitable means through the pipe is ejected into the mass of
fuel which is placed and burned on the tube-plates of the boiler.
o and o¹ are the air-diffusing pipes consisting of vertical tubes one situated beneath
the dead plate p of the furnace door and the other behind the bridge and surmounted
by a horizontal tube provided with perforations through which the air, which has
become highly heated in its passage through the tube is forced in the direction
indicated by the arrows in figures 2 and 3. Hot air issuing from the pipe o is thus
distributed over the surface of the fuel while that issuing from the pipe o' is distributed
into the combustion chamber.
is a sliding plate in the pipe n to regulate the supply of air to the furnace.
The tops of the pipes a, a, and I are advantageously covered with fire brick r.
By this arrangement when it is required to feed the boiler with water the valve fis
opened and the feed pumps are set in operation. The valve j will then automatically
close and the water will flow through the pipes e and d and the tubes a, a into the tank h
hence it will pass through the tubes a¹, a', and pipes d' and e' into the boiler, having
become highly heated in its passage through the furnace. As soon as the boiler is
sufficiently supplied, the valve is closed and the valve will automatically open,
whereupon a constant and rapid circulation of the water in the boiler will take place
through the pipes i and d, tubes a, a, a², a¹, and pipes and thus causing the water
to pass and repass through the midst of the incandescent fuel.
In figure 5, a and a³ are the two water tubes and is the air passage which is
formed by closing in the space between the two tubes with an upper plate s and a
lower plate t.
The tubes can be connected by a curved tube (not shown in the drawing) or by a

page_text: water tank such as that herein before described and shown at h in figures 2 and 3.
The air forced in, in a similar manner to that before described when referring to
figures 1 to 4, passes out into the fuel through cross tubes u, u fitted in the water
tubes a, a¹. An opening is made in the inner end of the air passage through which
air passes to mix with the escaping gases in order to complete their combustion
before they pass into the combustion chamber. The tube a is connected to the feed
water supply and to the circulating pipe (figure 1) and the tube a¹ is connected to the
combined feed water delivery and circulating pipe el. The arrangement of the said
pipes and of the air supply pipe is substantially the same as that shown in
figures 1 to 3 and therefore needs no illustration.
Instead of arranging the air passage between the water tubes, as shown in figure 6,
I can obviously place it below the said tubes.
Instead of employing ordinary bridges I sometimes fit the boiler furnace with an
air chamber or receiver into which the heated air is delivered by the tube or
passage before being diffused in the combustion chamber.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
(1.) The manufacture and use of an apparatus such as is herein described, and
consisting essentially of a number of water tubes, the space between which is formed
into an air passage having lateral apertures, the apparatus being adapted to be fitted
in the furnace tube of a steam boiler and to be connected to the boiler, substantially
in the manner and for the purpose setforth.
(2.) The apparatus shown in figures 4 and 5 adapted to be applied to steam boilers,
substantially in the manner setforth.
(3.) The improved steam boilers hereinbefore described with reference to the
accompanying drawing.
Dated the Sth day of September 1888
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicant.