Improvements in and Applicable to Steam Generators.
Year: 1888

page_text: Date of Application, 13th Sept.. 1888
Complete Specification Left, 13th July, 1889-Accepted, 17th Aug., 1889.
PROVISIONAL SPECIFICATION.
Improvements in and Applicable to Steam Generators.
I, THOMAS, LISHMAN,, of No. 29, Belithe Villas, Barnsbury, in the County of
Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:-
--
My invention relates more particularly to stationary and marine steam generators
or boilers, the object being to effect a more perfect combustion, to more fully utilize
the heat produced, and to heat the feed water to a higher temperature than hitherto,
also to produce a continuous circulation, and to prevent: undue expansion: and
contraction.
In carrying out my invention for general purposes, I construct the boiler, by.
preference, with an external cylindrical shell having the required.number of furnaces
and flues, the said flues delivering the gases into a combustion chamber, wherein.
the gases are supplied with a quantity of highly heated air,- from an air receiver or
receivers placed in the furnaces or flues; the gases are then conveyed, by tubes or
pipes to other combustion chambers, and are thereby thoroughly distilled, and all the.
heat evolved therefrom is utilized for the generation of steam.. The flues and com-
bustion chambers are furnished with a number of cross tubes for affording a, large
heating surface and effecting circulation. I may in some cases however employ, tubes;
running longitudinally through the combustion chambers.
The said receivers may be supplied with air by means of. one or more air tubes. or
channels resting on the floor of the furnace, through which air is driven; the said
tubes or channels are provided with a number of orifices or slits along each. side,
through which the air passes right and left to the fuel, resting on grate bars arranged
in the form of a basket and placed by preference transversely in the furnace,, under-
neath which a steam or water jet may be applied. I can also.advantageously inject
steam into the air-tube or tubes.
When applying my invention to existing boilers, if the grate bars be already
arranged longitudinally, they may remain so.
The air supply to the combustion chambers is regulated by suitably arranged
valves or slides. The fuel chamber is securely enclosed but provided with doors
which are formed hollow, and with a number of perforations for the admission of
air at the front end of the furnaces from a. main air cliannel or tube.
The feed water supply to the boiler is effected by an arrangement of pipes which
may pass through the furnaces or flues and.tubes of the boiler or combustion chambers
and be. connected by preference to a feed water receiver or, tank placed in any
convenient position.
Or the tank. may be dispensed. with, and the feed water be supplied.direct by the
pipes. By this arrangement. the water is caused to keep in constant circulation
through the whole apparatus.
I prefer to provide the apparatus with valves acting, automatically, whereby liability
to accidents or injury is prevented...
My improved arrangements for effecting combustion by means of forced draught
are also, applicable to boilers of the locomotive type especially; to torpedo-steamers
practically all the parts are of circular form with a vertical fuel chamber and. longi-
tudinal combustion chamber or chambers, so. arranged that when required,, they can
be disconnected and the ends of each are removeable. The outlet for escaping gases
may be..placed, underneath, instead, of, at the top and passes over-board,,a.cliimney
being thus dispensed, with..

page_text: The arrangements for effecting combustion, the feed water supply and the general
construction are substantially the same as those hereinbefore described.
In all cases the boilers can be arranged or constructed to allow of their being
fired from one or from both ends, that is to say, they can be provided with furnace,
doors at one or both ends.
Dated the 13th day of September 1888.
G. F. REDFERN, & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and Applicable to Steam-generators.
I, THOMAS LISHMAN, of No. 29, Belithe Villas, Barnsbury, in the county of
Middlesex, Engineer, 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 :-
My invention relates more particularly to stationary and marine steam generators
or boilers; the object being to effect a more perfect combustion, to more fully utilize
the heat produced, and to heat the feed water to a higher temperature than hitherto,
also to produce a continuous circulation, and to prevent undue expansion and
contraction..
In the accompanying drawings—
Figure 1 is a front elevation of a marine boiler constructed according to my
invention.
Figure 2 is a longitudinal section of the same on the line A B of figure 1.
Figure 3 is a transverse section on the line C D of figure 2; and,
Figure 4 is a horizontal section on the line E F of figure 2.
Figure 5 is a longitudinal section illustrating a modification.
Similar letters in all the figures indicate similar or corresponding parts.
Referring to figures 1 to 4, a is the outer shell of the boiler, which I have
shewn of cylindrical form, as being the most advantageous for general purposes,
and constructed with two inner cylindrical shells bb containing the furnaces cc,
and forming flues or combustion chambers d d, the said shells b b consisting by
preference of a series of solid-rolled or cast rings or tubes 62 connected together
by flanges and having strengthening projections or webs b* formed thereon as
shewn.
The gases generated in the furnaces cc pass into the combustion chambers d d wherein
they are supplied with a quantity of highly heated air from air-receivers or
distributors ee placed in the flues d d behind the fire-bridges ff. The air is supplied to
the air receivers or distributors e e by means of tubes or channels g g resting on the
floors of the furnaces c c, through which tubes air is forced by a fan or blower, not
shewn in the drawings. The tubes g g are provided with a number of holes h h along
éach side, through which a portion of the air passes to the fuel resting on curved
grate bars arranged transversely in the furnaces c c, as shewn in figure 2.
From each of the flues or combustion chambers d the gases pass to a transversely
placed combustion chamber and thence through tubes or pipes. j j to a similar
chamber k. In these chambers and the combustion of the gases is perfected
and being surrounded by the water of the boiler, all the heat evolved from the
said gases is utilized for the generation of steam. The products of combustion
pass off through the vertical flue 1.
i
The air supply to the combustion chambers is regulated by means of valves or
slides m m.
The front ends of the furnaces are provided with close fitting doors n
made hollow and communicating through short tubes oo with the air pipes 9 g
72'

page_text: The said doors are provided with a number of perforations through which a portion
of the air forced through the tubes g is directed onto the burning fuel, as indicated
by the arrows in figure 2.
The feed water supply to the boiler is effected through a pipe p connected with
the feed pump (not shown) and provided with vertical branch pipes q, 9 passing
through the boiler shells a and b into tubes rr placed within and extending
along the flues or combustion chambers d d from near the bridges ff to the back end
of the boiler, where they are connected to a tank s. A space t is left around
each pipe where it passes through the shell 6 into the tube so that the latter
is open to the lower portion of the water space of the boiler.
The feed pipe p is connecte: to the tanks by a pipe provided with a back
pressure valve u.
is a cock for opening and closing communication between the
pipe p and the feed-pump. w is a blow-off cock for clearing out sediment from the
The tank is connected directly to the boiler through a pipe a provided
9-
tank s.
with a valve
The feed-pipe p is advantageously connected by a pipe z and automatic valve l
to the boiler, the said pipe entering one of the furnaces c and extending along the
side thereof to the back of the bridge, where it is connected by a cross tube a
to a similar pipe laid along the other side of the furnace c and passing out at
the front. Here it is connected by a short tube c¹ to a set of pipes and b
similarly arranged in the other furnace c and connected by a cross tube a', the
pipe b passing out through the front plate of the boiler and extending upwards
to near the top thereof, where it enters the boiler and is provided with a feed-
water delivery-valve d'.
1
By this arrangement of feed-water supply, when the valve is opened the feed-
pump will force water through the pipe p and a portion will pass through the
pipes and tubes into the tanks and the pressure will close the valve น. A
certain quantity of water will at the same time be drawn up from the bottom of
the boiler through the spaces tt, as indicated by the arrows, which water becomes
heated in its progress through tuber to the tank s. The water will deposit its
impurities in the said tank from which they can be blown out through the cock w,
and the purified water will flow from the tank through the pipe into the boiler.
A portion of the water will pass from the pipe p through the pipes z and bin
the furnaces c c and will, after being in this manner highly heated, pass into the
boiler through the valve d¹.
"
When the valve v is closed a constant circulation of the water will take place
through the whole system of pipes, tank and boiler.
The flues and combustion chambers can, if desired, be furnished with a number of
cross tubes for affording a larger heating surface and increasing the circulation; or
tubes may be employed for a like purpose running longitudinally through the combustion
chambers.
Steam or water jets may be applied underneath the furnaces c c and I can also
advantageously inject steam into the air-tubes g g.
When applying my invention to existing boilers, if the grate bars be already
arranged longitudinally they may remain so.
8
It will be obvious, that if deemed advisable, the tank & could be dispensed with and
the feed-water be supplied direct through the pipes in which case the pipes r would he
connected direct to the pipe x as shewn by the dotted lines in fig. 2.
I prefer to provide the apparatus with valves acting automatically, whereby liability
to accidents or injury is prevented.
If it be required to use the boiler with a natural draught this can be done by
substituting suitable doors for those shewn in the drawings, and the air-tube g in this
case would not extend beyond the front plate of the boiler.
My improved arrangements for effecting combustion by means of forced draught
are also applicable to boilers of the locomotive type, especially to torpedo-steamers,
practically all the parts are of circular form with a vertical fuel chamber, and

page_text: 1
•
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longitudinal combustion chamber or chambers, so arranged that when required, they
can be disconnected and the ends of each are, removable. The outlet for escaping
gases may be placed underneath instead of at the top and can pass overboard,. a
chimney being thus dispensed, with.
The arrangements for effecting combustion: the feed-water supply and the general:
construction are substantially the same as those hereinbefore described.
:
In all cases the boilers can be arranged or constructed to allow of their being fired
from one or from both ends, that is to say,, they can be provided with furnaces and
doors at one or both ends.
In the modification shewn in figure 5 of the drawings the boiler is constructed with
a vertical shell e and a horizontal shell a and communication between these two.
portions exists only through orifices and g¹, the former being for steam and the
latter for water, the furnace is arranged in the said vertical shell in the manner
shewn, and communicates at its upper part with the flue or combustion chamber d
placed in the horizontal shell, and projecting into the vertical shell; it, is closed at this
-end and is open at its other end to a chamber h¹ fitted with a number of air tubes i¹
having their ends secured in plates and ¹ forming partitions which divide the
chamber into an upper portion 1, a middle portion m¹ and a lower portion, which
is further divided by a plate n' into two chambers o¹ and p³, the latter of which com-
municates with a fan or blower or with the open air. From the chamber o extends
an air-pipe q leading to a hollow bed-plate arranged underneath the furnace grate.
The hollow door n for supplying air to the burning fuel communicates with the
hollow bed-plate by means of a pipe.s..
2
is a flue or chimney for carrying off the products of combustion.from the middle
chamber m¹.
The water tuber is placed within the flue or combustion chamber and its rear end
is in communication with a tanks and with the water space of the boiler, as in the
boiler illustrated in figures 1 to 4, but the tank is so placed that the communication
between it and the tube is effected directly by the pipe q. the pipe p being dispensed
with. The water tube. r opens at its front. end into the vertical portion e¹ of the
boiler.
A pipe forms direct communication between the tank and the boiler as in the
arrangement hereinbefore described with reference to figures 1 to 4, but the said pipe
leads to the lower part of the vertical portion of the boiler and serves for the passage
of the water from the boiler to the tank instead of from the tank to the boiler.
In this modified arrangement of the boiler the air which is fed to the furnace (the
course of which is indicated by the arrows) becomes highly heated by its passage
through the heating chamber, through which the escaping gases are compelled to
pass on their way to the chimney . From the chamber the hot air passes
through the tube into the hollow base plate up through the grate bars into the
midst of the fuel and also through the pipes and hollow door 'n onto the fuel. The
feed water also becomes very highly heated before its admission to the boiler. The
direction of circulation of the water.is indicated by the arrows.
u.is a tight-fitting door for allowing of the removal of ashes accumulating in the
hollow base plate 1.
It will be obvious that a chamber similar in principle to the chamber could be
employed for heating the, feed-water in which case the tank s would not be required.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
'
(1) In.a steam boiler the employment of flues or combustion chambers, arranged
as described, in combination with the means for effecting a supply and distribution of
air to the fuel and gases substantially as set forth and illustrated in figures 1 to 14 of
the accompanying drawings.
(2). In a steam boiler, the combination with a longitudinal flue or combustion

page_text: chamber such as d, of the feed-water tubes and pipes rp qz, b' and c¹ and with (or
without) a tank such as s all arranged as described and forming a communication
between the feed pump and the boiler for the purpose set forth
(3) The improved steam boiler hereinbefore described and illustrated in figures 1
to 4 of the accompanying drawings.
(4) The modified construction of steam-boiler herein before described with reference
to figure 5 of the accompanying drawings.
Dated the 12th day of Inl., 1980
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.