Improvements relating to the Generation of Heat in Furnaces and to Apparatus therefor.
Year: 1889

page_text: Date of Application, 31st Dec., 1889-Accepted, 8th Feb., 1890
COMPLETE SPECIFICATION.
[Communicated from abroad by ELIJAH BEANS CORNELL, of Philadelphia,
Pennsylvania, United States of America.]
Improvements relating to the Generation of Heat in Furnaces and
to Apparatus therefor.
I, HENRY HARRIS LAKE of the firm of Haseltine Lake & Co., Patent Agents,
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 relates particularly to the generation of heat through the agency
of steam injected into or through the fuel.
Heretofore it has been customary to increase the heat obtainable in a furnace by
increasing the consumption of fuel with relation to a given size of furnace. This
increase of consumption has been effected by increasing the draught or supply of
oxygen by various methods.
The method which is most closely connected with my improved method consisted
in injecting steam and air upon the fuel, dry steam being preferably employed. This
is a method of dissociating steam in which the action of the steam upon the fuel is to
part with its oxygen to the carbon of the coal or other fuel or to the carbonic oxide
formed from such fuel setting free the hydrogen, which is burnt at the expense of
indrawn atmospheric air. Such a method is wasteful of the heat units obtainable
from the steam for several reasons among which I cite the following:-
It is well known to chemists that on account of its great specific heat, hydrogen
has a comparatively enormous cooling effect. The increased combustion of fuel,
therefore caused by the separation of the oxygen and its combination with the carbon
of the coal or other fuel although giving greater amount of heat, does not result in
full advantage of that greater heat, as that heat is practically dissipated in heating the
hydrogen evolved. The heat therefore that results, is not the sum total of the beat
obtainable from the combustion of the constituent gases of steam between themselves,
but is a differential sum of the heats of combustion of the hydrogen in atmospheric
air, and the heat evolved from the combustion of the extra fuel, less the heat lost
from the latter combustion by the heating of the volume of hydrogen evolved. Thus,
while in a furnace so heated it is undoubtedly possible to obtain greater heat than by
a plain fire, it is only possible to obtain this greater heat, by the consumption of a
greater amount of fuel. Whilst it is true that an economy may appear to be effected
by the possible use of a cheaper fuel, the larger amount of the cheaper fuel consumed
results in no actual economy; and this is probably the chief reason why after lengthy
trials these methods are generally discontinued.
And this method of dissociating steam consists in causing that vapor to pass over
iron or similar material that will absorb the oxygen, setting free the hydrogen that
can be used as fuel.
I am aware that such processes are known, and have been extended in the arts as
regenerative processes, by which the oxygen absorbed has been caused to be given up
from the material through the application of greater or less heat. A layer of silver
has been used in this way, which when molten, absorbed the oxygen of steam passed
over it, but which, when cooled, gave up the oxygen. I mention such process
particularly to shew that I disclaim it as having only a prima facie similarity with
what I shall subsequently describe as my new method. All of these processes in
which dissociation occurs as the result of the affinity of a fuel or fuel material or
other substance for one of the constituents of steam, I consider to be wasteful, for the

page_text: reasons I have given, and for the further reason that steam when separated into its
constituent gases, oxygen and hydrogen, then consists of those gases in such proportion,
each relatively to the other, as will by their re-combination develope the greatest
amount of heat, obtainable from water as a primary source.
mean,
that
I will now explain that by the term dissociation of steam by heat, I
steam is resolved into its constituents by the loss of one of them through satisfaction
by that constituent of a chemical affinity; and that generally to this loss is due a lesser
heat than is obtainable by the combustion of hydrogen in oxygen. But, I term that
decomposition or resolution of steam into its constituent gases by heat without loss
of either constituent gas (in satisfaction of chemical affinity), producing an oxy-hydrogen
gaseous mixture thermolysis; and the effecting of thermolysis I term thermolysing.
By thermolytic action upon steam passed through platinum and porcelain tubes,
Grove, and also Deville, has shewn that this vapor may be resolved into its constituent
gases. I make use of this principle in my invention, and I have discovered that
steam passed through a cast iron tube, maintained at or above the temperature of
molten silver, is decomposed into its constituent gases without oxidation of the tube.
I have further discovered that this action cannot be obtained with plain wrought iron
tubes for the reason that the wrought iron tube is oxidised at the expense of the
oxygen of the steam in so short a period of time as to render plain wrought iron tubes
practically useless.
I advance the theory that the cast iron tubes are rendered inattackable by the
oxygen, for the reason that it becomes coated with a stratum of carbide of iron or
more probably, of a carbo-silicide of iron. 1 also advance as a theory explaining
this fact that hot wrought iron is more easily oxidized than is hot cast iron because
of its position in the electro-motive scale, being more positive than that of cast iron.
According to this invention, having caused the decomposition of the steam into its
constituent gases by the action of thermolysis in a heated cast iron tubular retort,
placed preferably in the hottest part of the furnace (which furnace is employed to
generate the steam,, to be passed through the tubular retort and therein subinitted to
thermolysis; or which steam may be obtained from a foreign source) I cause the
gases to pass into the closed ash pit situated beneath the grate-bars or their
equivalent in the furnace. If these grate-bars support a fuel, such as coal requiring
oxygen for its consumption, I supply that oxygen by causing the gases, as they flow
with their great initial pressure from the exit tube of the retort, to inject or induce
into the ash-pit the quantity of air necessary to the consumption of the fuel, without
any regard to the heat to be obtained from the consumption of the oxy-hydrogen
gaseous mixture. I wish it to be fully understood that I consider that the heat
obtained from the consumption of the oxy-hydrogen gaseous mixture, resulting from
the thermolyzing of the steam in the cast iron tube or retort, is wholly additive to
the heat obtained from the combustion of the fuel, by the injected or indrawn air,
which air I consider in no way a diluent of the oxy-hydrogen gaseous mixture.
But I have further discovered that the action of the fuel lying on the grate-bars,
so far as relates to the combustion of the oxy-hydrogen gaseous mixture in a catalytic
or contact action. That is, the gases will not, at the pressure and velocity at which
they issue from the injector ignite, and even when reduced in velocity and pressure
so as to become ignitable, they then ignite only as an explosive mixture, the explosion
causing discontinuance of the inflammation. It is, I believe, well known in chemical
science that an explosive gas mixture cannot be burnt continuously, or with a
continuous flame. Now I have discovered that if such gases resulting from the
thermolyzing of steam, be passed through the ashes of coal, that these ashes have
such an action at a proper temperature, as to cause the continued inflammation of the
oxy-hydrogen gaseous mixture and as the ashes are not consumed, nor does it appear
necessary that they should be at a temperature likely to maintain inflammation by
presenting a sufficiently heated substance to cause continuously infinitesimal explosions
which as a whole night appear to be continuous inflammation, I have concluded that

page_text: such action is a contact or catalytic action. More especially have I been forced to
this conclusion by the reson that asbestos affords a material which will by passing
the oxy-hydrogen gaseous mixture through it at a temperature below that required
to initially inflame such mixture maintain constant inflammation.
I base my opinion that this operation is catalytic on other experimental facts and I
wish it understood that whatever may be the nature of this action, I find such
catalytic material necessary in practice, to the coutinual inflammation of the gases.
I will now further describe my invention by considering the process as completed
by the joint combustion of the coal under the action of atmospheric air, together
with the combustion of the oxy-hydrogen gaseous mixture which combustions I
consider separate, but simultaneous operations, until the carbon of the coal becomes
exhausted, when I may and do, if I so prefer, cause the continued combustion, of the
oxy-hydrogen gaseous mixture to maintain the heat of the furnace. Thus by my
invention practically great economy is effected, and I am enabled to support
combustion at the expense of the cheaper fuel, water, with a minimum amount of
the more expensive fuel, coal, which amount I consider may be reduced to that
necessary to provide a layer of fresh air including that requisite to afford a means of
re-igniting the gaseous mixture when its current has been interrupted for the
reduction of the temperature for any required purpose, such as the reduction
of steam pressure should the furnace be employed in the heating of a boiler.
Although I have described the injection of the gases into the ash-pit, as taking
place below or beneath the grate-bar, supporting the fuel material, I wish it
understood that I consider this material and the grate-bars merely as a septum, and
its support, the septum having the catalytic action necessary to the operation of
continuous inflammation of the oxy-hydrogen gaseous mixture. By my invention,
very nearly absolutely perfect combustion is attained, evidenced by the transparency
of the flame burning above the layer of fuel material upon the grate-bars, this
transparency being such as will render visible the fire-bridge in a furnace several feet
in depth. With such nearly complete combustion a smoke stack may be dispensed
with and the omission of so expensive constructive work is a secondary advantage
of my method.
In order that those skilled in the art may practise my improved process, I will now
describe the preferred apparatus which I use. Referring to the accompanying
drawings, Figure 1 is a sectional elevation of a form of furnace equipped with a
form of devices for practising my invention, said devises comprising a catalytic
septum in itself either a fuel or not, a pipe for supplying steam from a distant source
a super-heater or dryer, a retort, and outlet pipe from the retort leading beneath the
catalytic septuin or mass.
Figure 2 is a similar view partially in perspective, showing a fuel catalytic mass or
septum and further, an air injector connected with the retort outlet pipe for causing
the gases from the retort to inject or induce air into the ash-pit or below the catalytic
mass or septum.
Figure 3 is an elevation of a preferable form of retort drawn to an enlarged scale.
Figure 4 is a side view of preferable form of injector for use with my improve-
ments; and
Figure 5 is a sectional elevation, partly in perspective of a furnace and adjacent
stationary boiler equipped with devices for practising my invention.
A represents a form of furnace for any preferred purpose, composed of fire-box B
having grate-bars b, ash-pit or chamber C, below said grate-bars, in which is located
a pipe or injector C₁ having connection c, c¹ with a retort D located within the fire-
box, preferably in such position that it is subject to the heat thereof, which while it is
hot enough to cause it to convert steam into its constituent gases by thermolysis as
before described, is not sufficient to fuse or otherwise deteriorate the retort. In the
form of furnaces shown in the drawing said retort is indicated as located beyond the
bridge-wall.

page_text: Said retort therefore in some furnaces like those for stationary locomotive and other
boilers, will be located in the hottest part of the furnace, as the heat therein is not
usually sufficient to fuse the retort, whereas in smelting or other like furnaces the
retort will be located without the field of the most intense part of the heat of the
furnace, or if located within said field, the retort will be suitably shielded or protected
against the most intense heat so as not to fuse.
The retort D may be of any suitable form. In practice I use a cast iron retort of
the V-shape as shown, which is of a larger area in cross-section within certain propor-
tions, than that of the inlet and outlet pipes d and c' connecting it respectively to the
boiler and the injector, so as to afford sufficient heating surface and room for
expansion of the oxy-hydrogen gaseous mixture, needed for the full decomposition of
the steam. If the retort however be too large in cross-sectional area, there is a
probability of allowing the formation of an inner core of undecomposed vapor which
will be carried forward with the gases and act detrimentally. The interior of the
retort is preferably lined or caused to be lined in any suitable manner with carbide
of iron, or carbo-silicide of iron to render it inoxidizable and avoid dissociation by
affinity as hereinhefore set forth. Any suitable form of injector (may be used, a
preferable form which I use in practice being that shown, described and claimed in
U.S. Letters Patent dated October 30th 1883 No. 287,754. The grate-bars b may be
constructed as desired of any suitable material. On these grate-bars is placed any
suitable catalytic material 62 forming what I have termed a septum, for acting on the
constituent gases of the decomposed steam as they pass through the same.
practice for steam boiler furnaces I use the fuel or coal as a catalytic material or
septum as it subserves the purpose of initially generating the steam and initially
inflaming the gases and maintaining constant inflammation.
In
If the steam boiler d', is located adjacent to the furnace and the steam therefrom
is dry only one retort D may be used, as indicated in Figure 5, but if at a distant
location or when from low pressure, foaming or priming of the boiler the steam is
wet, then two or more retorts D are used in the furnace as indicated in figures 1
and 2, and the first of which is used as a superheater for the steam before it passes
into that retort in which it is thermolyzed. When fuel or coal is dispensed with as a
catalytic material, the injector ( need not then be used, in which case the outlet
pipe c¹ from the retort is led directly into the ash-box or equivalent chamber and may
terminate in a downwardly turned end as desired, and as indicated by dotted and full
lines Figure 1.
The practice of my improved method with the above described apparatus is as
follows:-
The catalytic material in the fire box is first ignited or heated to initially generate
steam and heat the retort D, or retort and superheater or dryer D¹ in the fire box, if
the boiler d¹ is adjacent thereto, and to heat the retort D, or such retort and super-
heater or dryer D only, if the steam supply is brought from a distant location. The
dry steam entering the retort D, is by thermolysis decomposed into its constituent
gases, which pass through the injector when used or through the continuation of
pipe c¹ when the injector is not employed, and enter the ash-pit or chamber below the
grate bars b.
The gases as they pass through the catalytic material are acted upon and burned as
hereinbefore stated.
While the method above disclosed is practical with either form of apparatus which
I have shown and discribed, I wish it to be distinctly understood that I do not limit
myself to the use of this specific mechanism it being within the scope of my inven-
tion to practice my method with any apparatus adapted for its correct working and
for obtaining the result which I attain."
I wish it to be understood also that while I have described the retort D or such
retort and super-heater or dryer D₁ as made preferably of cast iron I do not limit
myself to this material but design that the claims directed to this feature shall be of

page_text: such general nature as to include any non-oxidizable material that is to say any
material not readily attached by the liberated oxygen during thermolytic action
above described.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent, I declare that what I claim is
First. The method of heating in furnaces which consists in thermolyzing steam into
its constituent gases and then subjecting these gases to catalytic action and combus-
tion substantially as set forth.
Second. The method of heating in furnaces which consists in forming steam, con-
verting such steam into an oxy-hydrogen gaseous mixture, distributing this gaseous
mixture through a catalytic mass and burning said gaseous mixture substantially as
set forth.
Third. The method of heating in furnaces which consists in thermolyzing dry or
superheated steam into its constituent gases and then subjecting such gases to catalytic
action and consumption, substantially as set forth.
Fourth. The method of heating in furnaces which consists in forming steam, drying
this steam, superheating it, converting it into an oxyhydrogen gaseous mixture, dis-
tributing this gaseous mixture through a catalytic mass and burning said gaseous
mixture, substantially as set forth.
Fifth. The method of heating in furnaces which consists in thermolyzing steam
into its constituent gases, subjecting such gases to the action of a catalytic mass in
itself a fuel and to combustion simultaneously with this fuel air being supplied to such
fuel to support its combustion substantially as set forth.
Sixth. The method of heating in furnaces which consists in thermolyzing steam
into its constituent gases subjecting such gases to the action of a catalytic material in
itself a fuel, and to combustion simultaneously with this fuel, air being supplied
to such fuel to support its combustion by injection by said gases substantially as
set forth.
Seventh. The method of beating in furnaces, which consists iu thermolyzing dry
or superheated steam into its constituent gases, distributing these gases beneath the
grate bars of a furnace, subjecting them to the catalytic action of a material whether
it be itself a fuel or not, and which material is situated above the grate-bars and con-
suming by combustion, the gases in and above said material having a catalytic action
substantially as set forth.
Eighth. In an apparatus for heating in furnaces, the combination of a steam
generator or supply, a furnace having a fire box and an ash-pit, a septum of a catalytic
material in said fire-box, a retort having an inoxidizable inner surface in said fire-box,
and pipe connections between said steam supply or generator and one side of said
retort, and between the ash-pit and the other side of said retort.
Ninth. In an apparatus for heating in furnaces, the combination of a retort having
an inoxidizable inner surface said retort being connected with a supply of steam a
septum of a catalytic material a chamber below said septum, and a pipe connection
between the retort and said chamber below the septum, substantially as set forth.
Tenth. In an apparatus for heating in furnaces the combination of a retort having
an inoxidizable inner surface, a super heater or dryer connected to said retort a steam
supply pipe for said super-heater or dryer, a septum of a catalytic material, a chamber
below such septum, and a pipe connection between the retort and said chamber below
the septum substantially as set forth.
Eleventh. In an apparatus for heating in furnaces the combination of a retort
having an inoxidizable inner surface said retort being connected with a supply of steam
a septum of a catalytic material, a chamber below said septum, a pipe connection
between the retort and said chamber below the septum, said retort being of larger
cross section than the connections from the steam supply to it and from it to said
chamber, substantially as set forth.

page_text: Twelfth. In an apparatus for heating in furnaces the combination of a retort of cast
iron or other non-oxidizable material connected with a supply of steam, a septum of
a catalytic material, a chamber below said septum, and, a pipe connection between
the retort and said chamber below the septum, substantially as set forth.
Dated this 31st day of December 1889.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.