Improvements relating to the Combustion of Fuel in Steam Boiler Furnaces, and to Apparatus therefor.
Year: 1893

page_text: Date of Application, 28th Aug., 1893-Accepted, 30th Sept., 1893
[Communicated from abroad by ANDERSON BLACKWILL COSBY, Master
Machinist, SAMUEL PROSKAUER, Attorney-at-Law, and MARK MEYER
STRAUSE, Dry Goods Merchant, all of Richmond, in the County of Henrico
and State of Virginia, United States of America.]
Improvements relating to the Combustion of Fuel in Steam Boiler
Furnaces, and to Apparatus therefor.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co. Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 :—
This invention, considered as a method, relates, more particularly, to promoting
and obtaining practically a perfect combustion of fuel in a boiler furnace, and
increasing the steam capacity of the boiler by preventing loss by the too free
escape of heated gases, and thus effecting economy in the use of fuel, as hereinafter
described.
Heretofore, that is to say, before the present invention, efforts have been made
to effect, practically, perfect combustion in a boiler furnace by means of a forced
draft and to realize the full benefits derived from such substantially perfect
combustion, but they have failed for the reasons, first, that either too much or too
little air was introduced under pressure to effect the required combustion; and,
secondly, thta the heated products of combustion, principally carbonic acid gas,
and the nitrogen constituting the incombustible element of the air introduced, were
allowed to escape too freely and at too high a temperature, thus carrying away heat
which should have been communicated to the water in the boiler and thus utilized
in the generation of steam.
In the invention, hereinafter fully described, the defects above enumerated are
obviated, practically perfect combustion is produced, and, at the same time, the
loss of heat resulting, as before stated, from the unnecessary discharge of intensely
heated products of combustion from the chimney, is prevented.
The
In carrying out the improved method, forming a part of the present invention,
the boiler is provided with a tight ash-pit and a tight furnace, and there is
introduced to the former a sufficient quantity of air under pressure to properly
combine with the fuel, and no more. The smoke box is also closed to prevent
waste of heat, leaving only for the exit of such products of combustion as are not
consumed in the furnace, a minute area of escape, and that only. The whole
subject of the combustion of fuel is thus reduced to one of calculation.
proper quantity of air for the purpose of combining with the fuel for supporting
combustion is forced into the furnace, there being taken into consideration, and
proper allowance made for, the nitrogen constituting the incombustible element of
the air forced in under pressure, and there are taken from the furnace only the
results of such combustion, which may be considered to consist of carbonic acid
gas and the nitrogen.
To properly effect this result with a given quantity_ or weight of fuel fed to the
furnace per hour, the requisite volume of air is introduced to the tight ash-pit to
combine with such weight of fuel, and the area of the exit aperture is adjusted in
accordance with the principles above stated.
Under this arrangement, excepting when starting the fire, no chimney is required,
except such as shall serve to carry off the incombustible gases which reach the
smoke box

page_text: In the accompanying drawings,
Fig. 1 is a longitudinal section of a common type of stationary boiler shown
adapted to the carrying out of the method and illustrating mechanical attachments
adapted for such purpose.
Fig. 2 is a similar view of a boiler of the locomotive type.
Fig. 3 is a similar view of a boiler of a known marine type.
Figs. 4, 5 6 and 7 are details, as will hereinafter be described.
In the drawings A represents the body of the boiler; B the furnace or fire box,
and C the smoke box. The ash-pit D is closed by front doors a through which
pass branches a¹ having air-delivering nozzles b, which, by preference, have long
and narrow mouths as shown in Fig. 4. The branches a' communicate with a
leading pipe a which in turn is attached to a blower E or other medium for
creating a blast. The pipe a² is furnished with a suitable damper a³, by means of
which the air under pressure may be shut off from the pipe a² its branches a¹ and
the nozzles b. The invention is not restricted to any construction of pressure-
producing apparatus, to the described devices for furnishing air to the ash-pit, to
the shape of the nozzles 6 delivering the air, or to other details, provided the air
shall be injected under the grate to produce the effect described.
In the smoke box, at a point just above the upper row of flues, or about at the
water line, is placed a diaphragm F which in itself may constitute a damper by
being arranged to move pivotally as shown in Fig. 5; or in two perforated parts,
one sliding upon the other, as seen in Fig. 6. Normally, or when the boiler is
steaming, the diaphragm F, if of the construction of Fig. 5, extends entirely across
the space between the flue sheet and the head of the smoke box, so as to tightly
close and shut off all escape except that of the small body of incombustible
gases.
In operation, the fire having been kindled, air is admitted under pressure under
the grate, the oxygen producing rapid combustion. It is to be understood that,
until the fire gains some headway, the damper is open and there is a free escape
of smoke and products of combustion through the flues to the stack as in ordinary
practice. If the damper is of the character shown in Fig. 5, in order to give free
escape to the stack, the damper is swung to a vertical position; but if of the sliding
grate description shown in Fig. 6, the moving portion of the damper is slid so as
to open the apertures to their fullest capacity.
Combustion having been fully established in the fire box, the damper must now
be closed; that is to say if it is of the character shown in Fig. 5, it must be swung
to a horizontal position, thus completely closing the space between the tube sheet
and the front door of the smoke box. There is, still, however, a minute escape for
the incombustible gases through the series of small apertures with which the
damper is provided. If the damper is of the sliding description, it is to be closed
except so as to leave the minute area of escape described. Thus the stack E is
practically closed and rendered inoperative; there being no need of a stack except
as a means of causing the liberation of the nitrogenous and other incombustible
products that pass through the flues. The release of these incombustible bodies
is effected by the draft of the stack as in ordinary practice, or by a steam blast as
indicated in Fig. 7, the nozzle of which extends above the damper. Such steam
blast or jet is found necessary in the locomotive class of boilers, where rapid
steaming and the consequent rapid liberation of the said incombustible gases are
required.
It is found that the best results are produced by placing the diaphragm or
damper in the smoke box almost immediately above the upper row of tubes, so that
the heated incombustible gases shall be detained, deflected or temporarily held back
in the smoke box, and below the water line of the boiler, before they are finally
delivered to the stack through the apertures existing in the damper.
All the units of heat temporarily retained below the water line are conducted to
the water and help to make steam, whereas those carried above the water line
have the effect only of superheating the steam which is of no practical value

page_text: inasmuch as the tension of the steam is not increased, hence a damper placed in the
chimney is not the equivalent of a damper or diaphragm placed in the smoke box
substantially at the water line.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents I declare that what I claim is :
1. The herein described method of economizing fuel by producing the proper
combustion thereof in a boiler furnace and preventing loss of heat resulting from
the too free escape of the heated incombustible elements released in the process of
combustion of the fuel, which otherwise should have communicated their heat to
the water in the boiler, the same consisting in feeding fuel to the furnace, feeding
air under pressure below the fire, temporarily arresting the incombustible gases in
the smoke box below the water line of the boiler, and allowing their escape in a
degree proportioned to the combustion produced in the furnace, substantially as
set forth.
2. The herein described method of producing the proper combustion of fuel in a
boiler furnace and preventing the loss of heat resulting from such combustion and
thus economizing fuel, the same consisting in feeding fitel to the furnace, feeding
air under pressure below the fire in such proportions as shall effect a combustion
practically without loss, temporarily arresting the incombustible products of com-
bustion in the smoke box below the water line of the boiler, and freeing them from
the smoke box by a draft proportioned only to the work of carrying off the said
incombustible gases, substantially as set forth.
3. The within described method of economizing fuel by producing the proper
combustion thereof in a boiler furnace and preventing loss of heat resulting from
the too free escape of the incombustible gases released in the process of combustion
of the fuel, the same consisting in feeding fuel to the furnace, maintaining air under
pressure below the fire, causing the ascent of the compressed air through the fire
into the combustion chamber, heating said air and causing it to mingle with the
products of combustion evolved, temporarily arresting the incombustible gases in
the lower portion of the smoke box in or near the plane of their entrance thereto
from the flues, or at a point practically at the water line of the boiler, and allowing
the escape of said incombustible gases in a degree proportioned to the combustion
produced in the furnace, substantially as set forth.
4. The combination herein described in a boiler having a tight ash-pit and a
tight furnace, of a fan or similar pressure producer, means for delivering the com-
pressed air under the grate, an adjustable diaphragm or damper which in its
normal position shall stand in the smoke box above the top row of flues or
practically at the water line of the boiler and close the space between the tube
sheet and the head of the smoke box, and shall be entirely closed except as to
minute openings for the escape of incombustible gases, and a chimney or stack for
conveying off said incombustible gases, substantially as set forth.
1002
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.