Improvements in and connected with Steam Boilers.
Year: 1892

page_text: Date of Application, 29th Jan., 1892
Complete Specification Left: 31st Oct.. 1892-Accepted, 3rd Dec., 1892
PROVISIONAL SPECIFICATION.
Improvements in and connected with Steam Boilers.
We, ERNEST GEORGE GEARING of Saxonhurst, Woolstone, Southampton in
the County of Hants, Engineer, and VIVIAN BYAM LEWES of the Royal Naval
College, Greenwich, in the County of Kent, Professor of Chemistry do hereby
declare the nature of this invention to be as follows:-
The calculated calorific value of the fuel used in the furnaces of steam boilers,
and also the calorific value obtained by calorimetric tests is invariably far higher
than the evaporative power as found in actual work, the difference in many cases
amounting to as much as 40%. This is mainly due to the following reasons.
The flame which plays along the upper part of a boiler furnace and which heats
the furnace crowns, combustion chambers, and tubes of the boiler, is cooled by
contact with the boiler plates to such an extent that it is extinguished at the
surface of the metal, leaving a thin layer of extinguished gases between the source
of heat and the plate. A certain percentage of these unburnt gases escapes with
the products of combustion up the funnel or chimney at the top of which they may
often be seen burning. Furthermore flame will only make absolute contact with
substances at the same temperature or hotter than itself, and the layer of
extinguished gas being a bad conductor of heat, there is not only the loss due to
imperfect combustion, but also a considerable loss due to the imperfect conduction
of heat by the layer of extinguished gas.
Another cause of loss is due to the large amount of heat carried up the funnel or
chimney by the products of combustion and inert nitrogen from the air, which often
leave the funnel of a marine boiler at a temperature sufficient to beat the same to
redness.
Now this invention has for object to obviate or mitigate the evils above
referred to.
The furnace gases can only be completely burnt in contact with substances at a
bright red heat, and in order to ensure this and also to prevent extinguished gases
which have not completed their combustion from stealing along the plates and
escaping unburnt to the chimney, and also to form a large heating surface, we
construct the furnace flue and also the combustion chamber in the case of a marine
boiler, of a number of short connected tubes or rings each formed at the ends with
inwardly projecting flanges or preferably with inwardly and outwardly projecting
flanges so that each tube is of or H shape as seen in longitudinal section.
These tubes, which are connected together by riveting or otherwise to form the
furnace flue or combustion chamber or both may advantageously be formed of
channel or H iron or steel of suitable thickness, bent to shape and connected at
the ends.
The tubes or rings are preferably made of circular form in cross section; this
form and the flanges imparting great resistance to collapse and enabling the
screwed stays commonly used in the combustion chambers to be in great part
dispensed with, thus leaving the furnace and combustion chambers more free than
has heretofore been usual to expand and contract when under steam, and when the
fires are being urged by forced draught, without unduly straining the tube plates
and the shell of the boiler.
To assist the complete combustion of the furnace gases and to protect flanges
we provide the inwardly projecting flanges with refractory material, as for example
firebricks, that are each formed with a groove or channel to receive the flanges of
two adjacent tubes. These bricks which are preferably rounded at the ends to
lessen the destructive action of flame thereou will become red hot when in use and

page_text: will thus admit of the complete combustion of the furnace gases whilst in contact.
therewith.
The parts of the inwardly projecting flanges in the ash pit may be covered with
loose metal plates, by a sheet iron tray which can be removed with the ashes, or by
fireclay to prevent trouble in removing the ashes. To prevent loss of heat by the
escaping products of combustion and hot gases we provide one or more regenerators
whereby the heat of the products of combustion and hot gases is utilized to heat
the air supplied to the boiler furnace.
Two regenerators of the ordinary reversible type provided with air and gas
reversing valves may advantageously be used for this purpose. These regenerators
may be arranged immediately above the smoke box or boxes of the boiler and be
provided with an external air trunk or trunks in communication with a fan or other
suitable air blower.
The valves for controlling the passage of air through the air trunk or trunks
and regenerators, and those for controlling the passage of hot gases through the
regenerators are connected by rods or other suitable mechanism in such a manner
that when one regenerator is in communication with the smoke box or boxes and
the products of combustion are passing through it, the air valves controlling the
passage to the air trunk or trunks from the fan or other blower are closed to such
regenerator but are open to the other regenerator so that the air required for
combustion can pass through the said regenerator and the trunk or trunks and
become heated and then pass to the furnace and into the combustion chamber,
doors being provided to prevent air escaping into the stoke hold in the case of
marine boilers.
This arrangement of forced draught and construction of furnaces and combustion
chambers is applicable to either single or double-ended marine boilers, or any other
type of marine boiler having internal_furnaces, and may also be applied to land
boilers of the Cornish, Lancashire or Locomotive type.
The means employed for intermittently reversing the position of the air and gas
valves may advantageously be made as nearly automatic as possible in their action.
For this purpose a Huid pressure motor, such as a steam, hydraulic, or air motor
may be used, the piston of which is attached to the rods or other mechanism used
for actuating the air and gas valves of the regenerator, and the distributing valve
or valves of the motor is or are connected to some moving part of the main engine,
so that when a certain predetermined number of revolutions have been made by
the main engine the distributing valve or valves of the motor will be operated and
the motor piston will be actuated, thereby reversing the positions of the air and
gas valves and also the regenerator through which the air and products of
combustion respectively pass.
The products of combustion after leaving the regenerators can be led into a
common funnel or funnels.
The valve or valves controlling the inlet of air to the furnace may advan-
tageously be so connected to the furnace door or doors or to the latch or latches
for securing the same in the closed position that the door or doors cannot be opened
without previously shutting off the air supply thereby preventing the escape of
flame through the doorway or doorways.
When two or more boilers are used the regenerators and fan or fans for one
boiler may advantageously be separate from those for the other boiler or boilers so
that an accident to any one boiler will not disable the other boiler or boilers. The
mechanism for actuating the furnace doors or air valves may be connected or not
as may be found desirable.
Dated this 20th dow of Tenue 1909

page_text: COMPLETE SPECIFICATION.
Improvements in and connected with Steam Boilers.
We, ERNEST GEORGE GEARING of Saxonhurst, Woolstone, Southampton, in
the County of Hants, Engineer, and VIVIAN BYAM LEWES of the Royal Naval
College, Greenwich, in the County of Kent, Professor of Chemistry, 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:-
The calculated calorific value of the fuel used in the furnaces of steam boilers,
and also the calorific value obtained by calorimetric tests, is invariably far higher
than the evaporative power as found in actual work, the difference in many cases
amounting to as much as 40%. This is mainly due to the following reasons.
The flame which plays along the upper part of a boiler furnace and which
heats the furnace crowns, combustion chambers, and tubes of the boiler, is cooled
by contact with the boiler plates to such an extent that it is extinguished at the
surface of the metal, leaving a thin layer of extinguished gases between the
source of heat and the plate. A certain percentage of these unburnt gases
escapes with the products of combustion up the funnel or chimney at the top of
which they may often be seen burning. Furthermore flame will only make
absolute contact with substances at the same temperature or hotter than itself, and
the layer of extinguished gas being a bad conductor of heat, there is not only
the loss due to imperfect combustion, but also a considerable loss due to the
imperfect conduction of heat by the layer of extinguished gas.
Another cause of loss is due to the large amount of heat carried up the
funnel or chimney by the products of combustion and inert nitrogen from the air,
which often leave the funnel of a marine boiler at a temperature sufficient to heat
the same to redness.
Now this invention has for object to obviate or mitigate the evils above
referred to.
The furnace gases can only be completely burnt in contact with substances at a
bright red heat, and in order to ensure this and also to prevent extinguished
gases which have not completed their combustion from stealing along the plates
and escaping unburnt to the chimney, and also to form a large heating surface, we
construct the furnace flue, and also the combustion chamber in the case of a
marine boiler, of a number of short connected tubes or rings each formed at the
ends with inwardly or outwardly projecting flanges between each adjacent pair of
which an annular plate may advantageously be rivetted so as to project say two or
three inches into the water space of the boiler; or the sections may be made with
both inwardly and outwardly projecting flanges so that each tube is of H shape as
seen in longitudinal section. These tubes, which are connected together by
rivetting or otherwise to form the furnace flue or combustion chamber, or both,
may conveniently be formed of channel or H iron or steel of suitable thickness,
bent to shape and connected at the ends.
The tubes or rings are preferably made of circular form in cross section for a
furnace and with circular upper and lower parts for a combustion chamber this
form and the flanges, imparting great resistance to collapse and enabling the
screwed stays commonly used in the combustion chambers, to be in great part
dispensed with, thus leaving the furnace flue and combustion chambers more free,
than has heretofore been usual, to expand and contract when under steam and
when the fires are being urged by forced draught, without unduly straining the
tube plates and the shell of the boiler.
To assist the complete combustion of the furnace gases and to protect the
inwardly projecting flanges, we provide such flanges with refractory material, as
for example firebricks. These bricks, which are preferably rounded at the edges

page_text: to lessen the destructive action of flame thereon, will become red hot when in use
and will thus admit of the complete combustion of the furnace gases whilst in
contact therewith. The parts of the inwardly projecting flanges in the ash
pit, may be covered with loose metal plates, or by a sheet iron tray which
can be removed with the ashes. Or these parts of the flanges and the spaces
between them might be covered up with material such as fireclay to form a level
surface in order to avoid trouble in removing the ashes. In this case the flanges
at the parts mentioned may be partly cut away.
In the accompanying drawings,
Fig. 1 is a longitudinal section; and
Fig. 2 an end view of a steam boiler furnace flue constructed according to this
invention.
Fig. 3 is a sectional view of part of such a flue to a larger scale.
The flue is constructed of a number of short rings or tubes 1 each formed at
the ends with flanges 2 so that it is of channel shape in cross section. In the
example shown the flanges 2 are arranged to project outwardly and between each
adjacent pair of them there is rivetted an annular plate 3 the inner periphery of
which is arranged to project into the flue beyond the internal surface thereof so as
to form an inwardly projecting flange, and the outer periphery of which projects
beyond the outer surface of the tubes or rings 1 and into the water space of the
boiler so as to form an efficient conductor of heat to the water therein. 6. 6 arc
fire bricks having rounded edges and within which the inwardly projecting
portions of the plates 3 are embedded for the purpose herein before mentioned. The
portions of the plates 3 that project into the ash pit may be cut away as indicated
at 3 in order to present a practically smooth surface to facilitate the withdrawal
of ashes.
Fig. 4 shows partly in longitudinal section and partly in elevation; and
Fig. 5 shows partly in front elevation, and partly in cross section, a marine
boiler in which the furnace fue and the combustion chamber are each formed of a
number of connected short rings or tubes 1 having at the ends both inwardly and
outwardly projecting flanges 2, 2ª respectively, so that each ring or tube is of
Hshape in cross section as shown to a larger scale in Fig. 6. The adjacent pairs
of flanges are in this case directly rivetted together the flanges at the inner end of
the flue and those at the forward end of the combustion chamber being rivetted to
a tube plate 7, whilst the flanges 2" and 2 at the rear end of the combustion
chamber are rivetted to the back plate 8. 6, 6 are fire bricks in which the inwardly
projecting flanges 2 are embedded for the purpose hereinbefore stated.
To prevent or lessen loss of heat by the escaping products of combustion and
hot gases we provide one or more regenerators whereby the heat of the products
of combustion and hot gases is utilized to heat the air supplied to the boiler
furnace.
Two regenerators of the ordinary reversible type provided with air and gas
reversing valves may advantageously be used for this purpose. These regenerators
may be arranged immediately above the smoke box or boxes of the boiler and be
provided with external air trunks in communication with a fan or other suitable air
blower.
The valves for controlling the passage of air through the trunks and regenerators,
and those for controlling the passage of hot gases through the regenerators, are
connected by rods or other suitable mechanism in such a manner that when one
regenerator is in communication with the smoke box or boxes and the products of
combustion are passing through it, the air valves controlling the passage to the air
trunks from the fan or blower are closed to such regenerator but are open to the
other regenerator so that the air required for combustion can pass through the said
regenerator and the trunks and become heated, and then pass to the furnace and
into the combustion chamber, doors being provided to prevent air escaping into the
stoke-hold in the case of marine boilers. The products of combustion after leaving
the regenerators can be led into a funnel or funnels common to them. The

page_text: highly heated air is caused to pass into the furnace through perforated plates, to
ensure proper distribution, and over the surface of the fuel in the furnace, and also
by a separate pipe into the combustion chamber where one is used, whilst a mixture
of hot and cold air, so proportioned as not to exceed say 100° to 150°, is passed into
the ash pit below the fire bars in order to prevent fusion of these bars that would
ensue after a short time if heated air alone were passed into the ash pit.
By regulating the quantity and temperature of the air passing under the fire-
bars, the fuel is burnt chiefly to carbon monoxide, which, meeting the highly heated
air passing over the fuel, completes its combustion to carbon dioxide and causes a
large volume of flame which heats the furnace crowns combustion chamber and
tubes and also ensures a sufficient combustion of fuel per square foot of fire
grate.
Cold air might be injected into the ash pit by steam together with hot air under
the fire-bars, which would also tend to reduce clinkering and increase the volume of
combustible gases produced, but as the use of steam might be considered objection-
able in the case of marine engines, it is advantageous to pass a certain proportion
of the air from the fan or blower without passing through the regenerators, through
a passage outside the hot air channels to the ash pit and if not sufficiently heated
in its passage, it can be mingled with some of the hot air by means of a slide valve
operated from the furnace front.
The arrangement of forced draught and construction of furnaces and combustion
chambers hereinbefore referred to is applicable to either single or double ended
marine boilers, or any other type of marine boiler having internal furnaces, and may
also be applied to land boilers of the Cornish, Lancashire or Locomotive type.
Fig. 5 is a side elevation partly in section of a double ended marine boiler
constructed with air regenerators and air trunks according to this invention.
Fig. 6 is an elevation of one end thereof, the front plate of the smoke box being
removed to show the air trunks more clearly.
Fig. 7 is an elevation and Fig. 8 is a vertical section each to a larger scale than
Figs. 5 and 6 of a furnace front showing how the lower ends of the air trunks are
constructed and placed in connection with the furnace flue ash pit and combustion
chamber.
99 are the smoke boxes at the two ends of the boiler. The uptake from each of
these smoke boxes consists of a casing 10 divided by a partition 10% into two com-
partments each containing refractory brickwork arranged chequer-wise, in a manner
well understood to form a regenerator 11 the lower end of which is controlled by a
hinged flap valve 12 having seats at 12" and 12" preferably of refractory material
such as asbestos. These seats serve to support the valve in its closed and open positions
respectively. The upper end of each regenerator is controlled by a similar valve 13
having a seat at 13. These valves are mounted on rock shafts 14 and 15
respectively that are provided with chain wheels 14" and 15ª and are connected by
a chain 16 the arrangement being such that both valves 12 and 13 for the same
regenerator will be opened or closed simultaneously. The lower shafts 14 are also
provided with chaiu wheels 14° connected by a chain 16" so that when the valves
for one regenerator are opened, those for the other regenerator are closed. The
rock shafts 15 can be connected and operated at suitable intervals by a lever, that
may be operated either by hand or automatically by any suitable means.
each side of the casing 10 is an air inlet 17 whence cold air supplied by
a fan can pass to the top of the corresponding regenerator when the corresponding
valve 13 is closed, and also to air trunks 18 that are arranged in front of
other air trunks 19. The upper ends of the air trunks 19 are in communica-
tion with a transverse air trunk 19" that communicates by openings at 19"
alternately with the lower end of each regenerator above it when the corre
sponding valve 12 is open, as shown at the left hand side of Fig. 6ª. Thus with
the arrangement described it will be understood that when the several valves 12
and 13 are in the positions shown, hot gases and products of combustion will pass
from the smoke box 9 to the funnel 9 by way of the right hand regenerator 11,
At

page_text: the supply of air to which at this time will be cut off by the portion 13b of the
valve 13, whilst air will descend through the left hand regenerator, previously heated
by the passage through it of hot gases and products of combustion and will pass
through the opening 19b to the transverse trunk 19" and thence to the hot air
trunks 19. Cold air will at the same time pass downward through all the air
trunks 18.
Each furnace front, which may conveniently be made as a casting is formed with
two air chambers 18 and 19 (Figs. 7 and 8) that surround the fire door opening 20
and are connected with the corresponding air trunks 18 and 19 respectively of
which they form the lower parts. The chamber 18 which receives heated air from
the trunk 19 above, is perforated at its inner side 18" so that hot air can flow over
the fuel on the fire bars 20, and at its lower part communicates with a channel 18°
whence hot air can pass by a pipe 21 to the combustion chamber 22 (Fig. 5) of the
boiler. The lower part of the chamber 19ª communicates by openings 19b, that are
controlled by a valve 23, with a chamber 24 that is in free communication with the
ash pit 25. The channel 18° is perforated at its top 18d for the passage of hot air
to the space above the fire bars and at the bottom is formed with openings 18e that
are controlled by a valve 26 and through which part of the heated air supplied to
such channel can pass and mix with the cold air supplied to the chamber 24 and
heat such air to a moderate temperature, for the purpose hereinbefore mentioned,
before it passes into the ash pit 25. 27 is the ash pit door which is kept closed
whilst the furnace is under forced draught.
The valves 23 and 26 for each furnace may advantageously be so connected to
the corresponding furnace door, or to the latch for securing the same in the closed
position, that the door cannot be opened without previously closing these valves
and thereby shutting off the air supply to the corresponding ash pit 25, thereby
preventing the escape of flame through the doorway 20 when the door is
opened.
In the arrangement shown for this purpose in Fig. 7, the door latch 28 is held by
a catch 29 forming part of a lever 30 pivoted at 31. The lower end of this lever is
formed with a slot to receive a projecting part 23 of the valve 23 which is con-
nected with the valve 26, the arrangement being such that when the lever 30 is
moved in the direction of the arrow to release the latch, the valves 23 and 26 will
be moved to the right and close the openings 19 and 18° which they respectively
control.
When a boiler is constructed with three furnaces, the furnace front of the centre
one may be provided with two sets of chambers 18" and 19" as in Fig. 7. When
two or more boilers are used the regenerators and fan or fans for one boiler may
advantageously be separate from those for the other boiler or boilers so that an
accident to any one boiler will not disable the other or others.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. In a steam boiler, a furnace flue or combustion chamber constructed of a
number of connected tubes or rings provided with inwardly projecting flanges, or
with both inwardly and outwardly projecting flanges, the parts of the said inwardly
projecting flanges exposed to the action of fame having applied thereto refractory
material such as firebrick that serves to aid in effecting complete combustion of the
furnace gases and also to protect the said flanges from the destructive action of
flame substantially as herein described.
2. The improved furnace flue for a steam boiler, constructed substantially as
herein before described with reference to and shown in Figs. 12 and 3 of the
drawings annexed.
3. The improved furnace flue, or combustion chamber, or both, for a steam boiler
constructed substantially as hereinbefore described with reference to and shown in
Figs. 45 and 6 of the drawings annexed.

page_text: 4. The combination with a steam boiler having a closed furnace, of reversible-
regenerators arranged above the smoke box of the boiler and through which hot
gases and products of combustion alternately pass on their way to the chimney, air
trunks adapted to be placed in connection with an air supply and with the furnace,.
and suitable air and gas reversing valves, the arrangement being such that when
one regenerator is in communication with the smoke box of the boiler so as to be
heated by the passage through it, of hot gases and products of combustion, com-
munication between it and the air trunks will be closed, whilst communication.
between the other regenerator and the air trunks will be open so that air can flow
through such regenerator and become heated on its way to the furnace substantially
as herein described.
5. A steam boiler having a closed furnace and constructed with reversible
regenerators such as 11, air trunks such as 18, 18", 19 and 19", and controlling
valves such as 23 and 26, these parts being constructed arranged and operating
substantially in the manner and for the purposes hereinbefore described with
reference to and shown in Figs. 5ª, 6ª, 7 and 8 of the drawings annexed.
Dated this 31st day of October 1899
W. LLOYD WISE,
Per. F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.