Improved Method of Supplying Fuel to Furnaces, and Apparatus therefor.
Year: 1899

page_text: Date of Application, 21st Jan., 1899-Accepted, 25th Feb., 1899
COMPLETE SPECIFICATION.
Improved Method of Supplying Fuel to Furnaces, and Apparatus
therefor.
I, GEORGE WILTON, of the Gas Light and Coke Company's Tar and Liquor
Works, Beckton, in the County of Essex, Chemist, 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;-
My invention relates to the supplying to the furnaces of steam generators and
other boilers, heaters and the like of coal or like fuel, and to the regulation
of the air-supply necessary for the secondary combustion thereof in practically
just such volume as may be required for the efficient combustion of any class of
coal or fuel. The invention is particularly applicable to furnaces made in
accordance with Letters Patent No. 6645 of A.D. 1891 granted to me and another,
wherein the air-supply for the primary combustion of the fuel is delivered through
a perforated blast-pipe laid at the lower part of the furnace and in use completely
covered with and by the fuel.
In the past, attempts have been made to mechanically introduce and burn
pulverulent fuel such as "breeze," coal dust and the like, but these have not, I
believe, proved successful owing chiefly to the danger of explosion of coal and
other dust fuel, and secondly, to the difficulty of preventing the small particles
and dust being carried by the draught beyond the fire-bridge.
The object of my present invention is to secure by automatic means and without
hand-firing a regular supply and distribution of fuel and secondary air and
thereby to attain more perfect combustion of the fuel; in other words, to obtain
as high a percentage as practicable of carbonic-acid gas in the is:uing or chimney
gases, and thereby to prevent waste of heat.
With ordinary furnaces whether fired manually or mechanically the average
percentage of carbonic-acid existing in the chimney gases is about 10, whereas
by my invention I am enabled to increase the percentage to a constant 18 or
thereabouts, as found by experimental tests.
According to my present invention I use for the most part small coal or fuel,
that is to say, fuel reduced to about the size of what is known as "nuts," and I
also use "breeze"; this fuel is brought by a conveyor to a hopper whence it is
fed in required quantity to an injector preferably swivelled so as to be adjustable
in the vertical plane, the better to regulate the distribution of the fuel under
varying conditions. From the injector the fuel is blown into the furnace by a
steam-jet and the air for secondary combustion is partly introduced therewith
and partly through an aperture in the closed furnace-front, the amount of such
air-supply being regulated by the force of the steam-jet.
I will now fully describe one application of my invention in reference to the
accompanying drawing in which Fig. 1 is a front elevation of a "two flue" or
Lancashire boiler, the right hand furnace being shown in section on line 1-2
of Fig. 2, and Fig. 2 is a longitudinal section of one furnace showing my novel
apparatus in elevation, with an optional additional element hereinafter referred to.
The boiler furnace illustrated is in accordance with the patent above referred

page_text: to, no fire-grate being used and the air for primary combustion being introduced
through the perforations of a blast-pipe P laid in the furnace, bottom and
completely covered by the fuel charge. In the drawing, C is the pipe or conduit
through which the fuel is conveyed either by a screw or pusher and from which
it falls through the apertures to the feed hoppers H H. Below each of
these hoppers it is preferred to fit a worm W to work out the coal and prevent
bridging and sticking thereof. The fuel then falls into a second vertical hopper
or receiver R below the outlet orifice of which is disposed the receiving orifice i
of the fuel injector I projecting into the furnace. It is advantageous to fit a
sliding sleeve as at normally covering the space between the base of the
receiver R and the mouth of the injector I. The injector I is preferably pivotted
at for the purpose of enabling it to be easily adjusted by hand in the vertical
plane, the better to distribute the fuel over the furnace under varying conditions
of size, weight, strength of blast and so forth. Steam is led through the pipe
to the nozzle A at the outer end of the injector. The front of the furnace F is
closed at but around the injector is left an annular orifice B, either concentric
or eccentric therewith. F is a clinkering door.
It
In use the furnace being alight and the primary air being supplied through
the perforations ? of the blast-pipe P as above stated, the fuel as it falls from
the receiver R into the injector I is instantly swept forward by the steam-jet
issuing through nozzle A, and spread out fanlike into the furnace F and evenly
distributed (according to the specific gravity of its particles) over the surface
thereof, the distribution being varied as desired by adjusting the angular position
of the injector. The proper amount of air for the secondary combustion of the
fuel is drawn in partly with the blast, and partly through the orifice B.by the
action of the jet and the draught, and in proportion with the force of the jet.
I may in some cases use in combination with the fuel injector I a curved
concentric trumpet-mouthed baffling sleeve such as is shown in section at C¹.
This is supported upon the injector and by its action under the steam-jet smoke
and unconsumed gases are sucked back and eddy about the front end of the
furnace and are thereby better exposed to the flames and more readily burned.
The invention is specially useful where the natural draught of any furnace
is deficient, and there is no liability to damage of the flues which are always
under air compression internally instead of air tension and partial vacuum, as
is usual. The fuel supply and distribution are more regular than with hand
firing, and smoke is avoided.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is;-
1. The method of automatically supplying coal or other fuel to furnaces and
adjusting the volume of air required for its secondary combustion, which consists
in injecting the fuel by means of an injector and a steam-jet, and regulating
the said air-supply by the force of the latter, substantially as described.
2. The apparatus for supplying coal or other fuel to furnaces consisting in
the combination with feed devices such as are described of an injector preferably
arranged to swivel, and adapted to receive the fuel and a steam-jet for injecting
same, with or without the internal baffling sleeve, all arranged substantially
as described and illustrated in the drawings.
Dated this Twenty-first day of January 1899.