IMPROVEMENTS IN THE
Year: 1883

page_text: LETTERS PATENT to Alexander Melville Clark of the firm of A. M and
W. Clark of 53 Chancery Lane in the County of Middlesex Fellow of the
Institute of Patent Agents for an Invention of IMPROVEMENTS
IN THE
LETTERS PATENT to Alexander Melville Clark of the firm of A. M and
W. Clark of 53 Chancery Lane in the County of Middlesex Fellow of the
Institute of Patent Agents for an Invention of IMPROVEMENTS IN THE
METHOD OF PROMOTING THE SURFACE COMBUSTION OF FUEL IN STEAM BOILER
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 17th August 1883.
«
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane in the County of Middlesex, Fellow of the Institute of Patent Agents,
IMPROVEMENTS IN THE METHOD OF PROMOTING THE SURFACE COMBUSTION OF
FUEL IN STEAM BOILER FURNACES," [communicated to him from abroad by
Byron Sloper, of the City County and State of New York, United States of
America]
"
The object of the present invention is to effect as nearly as possible a complete
and perfect consumption of combustible material in the fire-box of a furnace,
whereby the inconvenience attendant upon the escaping smoke, sparks and cinders
is obviated, and a large saving in fuel is effected by consuming valuable heat,
producing materials which have heretofore been lost, by imperfect surface
combustion, and carried off by the exhaust.
These objects I attain by decomposition of a broad thin stratum of steam
distributed over and into the whole surface of a fire in conjunction with a similar
stratum of air artificially and purposely heated, to nearly the temperature of the
fire, by which, in conjunction with the fuel by which I cause the decomposition
of the steam and free or what may be called "hypothetical" carbon arising from
the ordinary imperfect combustion into carbonic oxide gas, by the union of the
oxygen of the steam with said carbon and this together with the carbonic oxide
resulting from the decomposition of the steam by contact with the incandescent

page_text: fuel employed. setting free the hydrogen of the steam will cause all the combustible
products to be at once reunited and converted into aqueous vapor and carbonic
acid, by the instantaneous chemical reaction caused by the contact of highly
heated and rarefied air accompanying and driven over with the steam, into the
whole fire surface, by a distributed current of steam, the steam causing the air
to "hug" or to be held to the fuel, so that the disassociated elements hydrogen
and carbonic-oxide may recombine with the oxygen of the heated air, without the,
heretofore prejudical action of the cold nitrogen forming a large volume of the
nir, on the steam, which would cool it and prevent continuous action in its
decomposition. By these means the greatest possible available heat-producing
materials, such as carbonic oxide, hydrogen and free or "hypothetical" carbon, in
the form of smoke or sparks are utilized, in such manner as to leave the draft
perfectly free, without in any manner checking or impeding it and rendering spark
arresters unnecessary.
Among the advantages attendant upon this invention is the fact that by
hugging and holding the air to the fuel, by the distributed stratum of steam,
I am enabled to thoroughly bring about the mutual decomposition of the steam,
heated air and the carbonaceous and gaseous materials of the fuel which have
heretofore been carried off by the exhaust, and prevent the cooling of the flues of
the boiler by a volume of cold nitrogen.
I will describe an example of one of the various means which may be employed
for carrying the invention into effect, consisting of one or more tortuous flues of
refractory material fixed within the fire box so as to be in contact with the
incandescent fuel said flue being open to the outer air at bottom through the
grate bars and of one or more steam injectors directed across the upper end of
said flue or flues whereby the air is carried through the flue by the induction
of the blast or current of steam, and at a temperature equal or nearly equal to
that of the incandescent fuel, and a current of dry superheated steam is distributed
under pressure in a broad thin stratum over the stratum of air, and the air is
brought into conjunction with the fuel by the stratum of superimposed steain and
held to the surface of the fuel or caused to "hug" so as to effect the thorough
mutual reaction before mentioned.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Patent Office on the 14th February
1884.
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane in the County of Middlesex Fellow of the Institute of Patent Agents.
"IMPROVEMENTS IN THE METHOD OF PROMOTING THE SURFACE COMBUSTION OF
FUEL IN STEAM-BOILER FURNACES A communication to me from abroad by
Byron Sloper of the City, County and State of New York, United States of
America
The object of the present Invention is to effect, as nearly as possible a complete
and perfect consumption of combustible material in the fire-box of a furnace
whereby the inconvenience attendant upon the escaping smoke, sparks and cinders
is obviated, and a large saving in fuel is effected by consuming valuable heat-
producing materials which have heretofore been lost by imperfect surface
combustion, and carried off by the exhaust.
These objects I attain by the decomposition of a broad thin stratum of steam
distributed over and into the whole surface of a fire in conjunction with a similar
stratum of air artificially and purposely heated, to nearly the temperature of the
fire by which in conjunction with the fuel by which I cause the décomposition of
the steam and free or what may be called "hypothetical" carbon arising from the
ordinary imperfect combustion into carbonic oxide gas, by the union of the oxygen
of the steam with said carbon and this together with the carbonic oxide resulting
from the decomposition of the steam by contact with the incandescent fuel
employed setting free the hydrogen of the steam will cause all the combustible
products to be at once reunited and converted into aqueous vapor and carbonic
acid, by the instantaneous chemical reaction caused by the contact of highly heated
and rarefied air accompanying and driven over with the steam into the whole fire
surface, by a distributed current of steam, the steam causing the air to "hug" or
to be held to the fuel, so that the disassociated elements-hydrogen and carbonic-
oxide may recombine with the oxygen of the heated air, without the heretofore
prejudicial action of the cold nitrogen forming a large volume of the air on the
steam, which would cool it and prevent continuous action in its decomposition. By
these means the greatest possible available heat-producing materials, such as
carbonic oxide, hydrogen and free or "hypothetical" carbon, in the form of smoke
or sparks are utilized in such manner as to leave the draft perfectly free without
in any manner checking or impeding it and rendering spark arresters unnecessary.
Among the advantages attendant upon this invention is the fact that by
hugging and holding the air to the fuel, by the distributed stratum of steam, I am
enabled to thoroughly bring about the mutual decomposition of the steam, heated
air and the carbonaceous and gases materials of the fuel which have heretofore
been carried off by the exhaust, and prevent the cooling of the flues of the boiler
by a volume of cold nitrogen.
The accompanying drawings illustrate one method of carrying the invention into
effect, but various other means may be employed without departing from the spirit
of the Invention.
In the said drawings. Figure 1 represents a longitudinal sectional view of a
boiler showing the invention applied thereto. Figure 2 is a longitudinal.
horizontal section of the same, and Figure 3 a perspective view of the tile
or section, through which the air passes prior to entering the furnace.

page_text: The letter A indicates the fire-box of the boiler furnace which may be of the
usual or of any approved construction. B indicates a section or tile of any suitable
refractory material, having a tortuous flue C, which extends from the water legs
at each side of the boiler, and is open to the outer air at the bottom on a line with
the grate bars, and which has an opening or recess E at the top through which air
passes or is injected into the furnace by steam passed directly above said opening
or recess. Above said slot are one or more steam injectors F extending into the
furnace, being connected by means of a pipe G.with the dome of the boiler
whereby a current of dry or superheated steam may be distributed under pressure
in a broad thin stratum over the stratum of air, and ensure the reactions
herein before mentioned.
The air is carried through the tile or section by the induction of the blast or
current of steam and at a temperature equal or nearly equal to that of the
incandescent fuel and is brought into conjunction with the fuel by the stratum of
superimposed steam and held to the surface of the fuel or caused to "hug" it so
as to effect the thorough mutual re-action before mentioned. The fuel rests upon
the grate bars H, as usual and the strata of steam and air are forced from the
rear forward near the surface at an angle of not over thirty degrees so as to not
force the gases too much into the fuel, but carry them off, and assist the draught of
the exhaust. The steam and air are carried under the fire-bridge indicated by the
letter I to the rear of the furnace, but in some instances where the length of the
fire-box is considerable, an additional tile or section and injectors may be located
at the front of the fire-box so as to effectually subject the fuel to the action of the
steam and air.
By practical experience I have found that in order to successfully and
continuously decompose steam on the surface of carbonaceous material, it is of the
utmost importance that the fuel upon which the steam impinges should be kept at
an incandescent white heat in order for the oxygen of the steam to unite with the
free carbon of the fuel, otherwise the steam will pass off undecomposed and
become an injury to the fire. By this process of bringing the air in contact with
the steam in such a highly heated state the large contained volume of nitrogen is
prevented from cooling the steam and fuel and counteracting the beneficial effects
of the oxygen and preventing thorough decomposition. Thus I am able by this
method to keep the surface of the fuel at a white heat and keep up and maintain
the re-action and decomposition continuously from the start.
Having described the nature of the said Invention and the manner of performing
the same I declare that what I claim as the Invention to be protected by tho
herein before in part recited Letters Patent is:
The herein described process of promoting the surface combustion of fuel, and
bringing the same to an intense incandescent heat, by the decomposition of steam
in connection with highly heated air, both the steam and air being delivered in a
broad thin stratum over and into the whole surface of the fuel so that all tho
atoms of steam comic into instant contact with the fuel substantially as and for the
purpose specified.
In witness whereof, I the said Alexander Melville Clark, have hereunto sot my
hand and seal this fourteenth day of February A.D. 1884.