Improvements relating to the Prevention of Smoke in Furnaces, and to Apparatus therefor.
Year: 1899

page_text: Date of Application, 3rd Feb., 1899-Accepted, 11th Mar., 1899
[Communicated from abroad by JOHN MACNAULL WILSON, of 11, Broadway, New
York City, New York, United States of America.]
Improvements relating to the Prevention of Smoke in 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:-
The invention which forms the subject of the present application for a patent
is a new and improved method of and apparatus for the prevention of smoke in
furnaces, especially those in which soft coal is burned, and for rendering more
complete and effective the combustion in furnaces generally whether using soft
or hard coal or other fuel, and thereby economizing the fuel.
It is well known that carbon is released from soft coal at a comparatively low
temperature, and that under ordinary conditions its combustion is not only incom-
plete, but that the liberated carbon tends, by reason of its density, to smother or
to retard the action of the fire. Many expedients have been adopted and proposed
for reducing the volume of smoke which results from this action, but few if any
plans have been devised which, if effective to any marked degree in consuming
the smoke and products of imperfect combustion, can be carried on economically.
This invention has for its primary object to effect a more complete combustion
of the smoke or combustible gases and vapors, and in a more economical way than
has heretofore been done, and to this end the invention, in its main features, con-
sists in the introduction, in a novel manner over the fire bed of a boiler or other
furnace, of air, preferably heated, together with certain chemical reagents containing,
chiefly, oxygen, hydrogen and nitrogen, and capable of yielding freely at a moderate
temperature oxygen and hydrogen which tend to rapidly raise the temperature
of the furnace and more completely effect the combustion of the carbon before it
can pass off from the lack of proper supporters of combustion, as carbonic oxide
or smoke.
It is well known that air alone, whether hot or cold, supplied over the fire bed
of a furnace will not prevent the giving off of smoke. It is also known that the
presence of chemical reagents which are supporters of combustion and which have
been introduced along with the fuel, do not afford an efficient or economical remedy
for the trouble, but I have demonstrated that by the union of air and such reagents
and their simultaneous introduction in the manner hereinafter set forth, the smoke
may be almost wholly prevented and fuel saved.
In carrying out my invention I employ, by preference, as the chemical reagent
saltpetre, either alone or together with black oxide of manganese in varying pro-
portions up to equal parts of each, according to the character of the fuel, but any
other chemical equivalent for the same may be employed, provided it will give off
the proper gases for supporting combustion in a similar manner.
This material or compound is conveyed into the furnace and distributed over

page_text: the fire bed in a fine state of subdivision by a jet or blast of air. If the material
is used in a dry state it is reduced to a finely powdered condition and blown into
the furnace in properly regulated quantities. But I prefer to use the saltpetre or
its equivalent in solution, either with or without powdered manganese dioxide
in suspension therein, and to introduce it in the form of spray into the fire box.
Any apparatus may be employed for carrying out my invention that is suitable
for the purpose, and that will secure the described results, but in order to more
clearly illustrate the nature and purposes of the improvement I have shown in
the accompanying drawing a special means which I have devised and which is or
may be used for the purpose..
Fig. 1 is a perspective view of a furnace provided with means for carrying out
the invention, a portion of the wall being removed to show the arrangement of the
devices.
:
Fig. 2 is a longitudinal section of the same.
Fig. 3 is a plan view of the grate bars and the spraying devices.
Figs. 4, 5, 6 and 7 are detailed views on an enlarged scale of the improved
device for introducing the chemical and air into the furnace.
The furnace A is of any ordinary construction. The devices for distributing
the air and the chemical reagent are preferably located in the corners at the
forward end of the fire box, and the spraying nozzles are located in said corners
above the fire.
The air is forced into the furnace by any convenient means, such as by a rotary
blower 3, from which an air pipe C leads to the upper part of the furnace wall.
Two branches D, D, lead from the main air pipe into the furnace and extend
downward either through the wall or through passages formed by fire brick inside
the furnace to the spraying nozzles E.
The nozzles are composed of castings divided by partitions F into two compart-
ments. The lower compartment has an opening G extending nearly the entire
width of the widened end of the nozzle, while the upper compartment opens into
the furnace through a row of orifices H.
I is a tank for containing the solution. It is conveniently placed above the
furnace, and a pipe L extends from the same in two branches either outside of or
within the furnace to points slightly above the nozzles E.
The pipes conveying the solution pass through the walls of the nozzles and
terminate in the upper compartments in a horizontal distributing pipe M from
which run small pipes N terminating at or near the orifices H.
When a blast of air is forced into the furnace through the air pipes, a portion of
the air passes into the furnace through the lower compartments of the nozzles,
while the remainder blows out through the orifices H and draws along with it
the solution from the pipes N and distributes it in the form of spray throughout
the fire box above the fire, where it combines with the unconsumed products of
combustion.
By leading the air pipes into the furnace through the walls or in any way where
it will be heated by the fire itself, the use of an independent heater is avoided.
The heating of the air, however, which is essential to the success of the system
may be effected in any other way. It may also be remarked that any other con-
venient means may be employed for mixing the chemical solution with the air,
and for introducing the two together into the furnace, the essential feature of my
invention in this respect being the introduction of the heated mixture into the
furnace above the fire and not in conjunction with the fuel proper.
The exact location of the sprayer, or the number of such sprayers, is largely
immaterial, it being only necessary that the proper distribution of the materials
should be effected.
The pressure of the air which is introduced along with the chemical reagents
into the furnace and which sprays and distributes the same, may vary within
considerable limits, but under ordinary working conditions, a pressure of two
ounces to the square inch will be found sufficient to distribute the chemical in

page_text: proper amounts over all parts of the furnace and render the assistance to combus-
tion which is desired.
In describing my invention I have referred only to the use of air as the medium
for spraying or distributing the chemical and assisting in the combustion, but it
will be understood that any equivalent gas or vapor may be substituted, as for
example steam.
Inasmuch as the method results in economy in the consumption of fuel, the
chemical may be distributed and the air blast maintained during the entire time
that the boilers are in operation, but it will be understood that the process may
be discontinued after the carbon has been consumed if smoke prevention is the only
object.
Among the advantages of my invention, it results that the fuel requires no
special treatment or manipulation, no special construction of furnace or boiler is
required as the improvement may be applied to any existing furnace, at very small
cost, and by the use of many devices in common use.
Having now particularly described and ascertained the nature of the said in-
vention 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:-
1. The method of preventing smoke from furnaces, which consists in introducing
into the fire box above the fire and so as to combine with the unconsumed products
of combustion therein, a chemical reagent which yields gases which are supporters
of combustion, and air, as set fortli.
2. The method of preventing smoke from furnaces, which consists in intro-
ducing into the fire box above the fire and so as to combine with the unconsumed
products of combustion therein, a chemical reagent in a finely divided condition,
which yields gases which are supporters of combustion, and air, as set forth.
3. The method of preventing smoke from furnaces, which consists in intro-
ducing into the fire box above the fire and so as to combine with the unconsumed
products of combustion therein, a chemical reagent in the form of spray, which
yields gases which are supporters of combustion, and air, as set forth.
4. The method of preventing smoke from furnaces, which consists in
introducing into the fire box above the fire and so as to combine with the
unconsumed products of combustion therein, a solution of a chemical reagent which
yields gases which are supporters of combustion, and spraying said reagent by a jet
or blast of air within the fire box, as set forth.
5. The method of preventing smoke from furnaces, which consists in dis-
tributing in the fire box above the fire and so as to combine with the unconsumed
products of combustion therein, a finely divided chemical reagent which yields
gases which are supporters of combustion, by a jet or blast of hot air, as set forth.
6. The method of preventing smoke from furnaces, which consists in introducing
together into the fire box above the fire and so as to combine with the unconsumed
products of combustion therein, a chemical reagent which yields gases which are
supporters of combustion, and hot air, as set forth.
7. The spraying nozzle herein described having the two compartments, the
upper compartment opening into the furnace through a series of orifices in which
the solution pipes terminate, as set forth.
8. The spraying nozzle herein described having a wide orifice for the passage
of air into the furnace and a series of orifices above the same in which terminate
pipes conveying a solution from a suitable reservoir.
Dated this 2nd low of Rahman 1000
HASELTINE,, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.