IMPROVEMENTS IN FURNACES, AND IN THE METHOD OF CHARGING THEM WITH FUEL TO IMPROVE ITS COMBUSTION AND PREVENT SMOKE
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by William Joslin at the Office of
the Commissioners of Patents, with his Petition, on the 28th
January 1873.
I, WILLIAM JOSLIN, of Lower Norwood, in the County of Surrey, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
FURNACES, AND IN THE METHOD OF CHARGING THEM WITH FUEL TO IMPROVE ITS
COMBUSTION AND PREVENT SMOKE," to be as follows:-
This Invention has for its object the more perfect combustion of coal
in ordinary boiler and other furnaces, for the prevention of smoke by an
improved method of arranging the fire-bars, and in charging and con-
suming the coal therein.
In place of setting the grate bars with wide spaces between them as
heretofore practiced, according to my improvements I arrange them
with spaces between them not exceeding three-quarters to half an inch or
even less (by preference using lump coal only, except when the fuel
is highly ignited as herein-after described). Or the fire-bars may be
made with vertical, parallel, or conical narrow grooves, passages or

page_text: channels up their sides, and placed close together, the channelled sides
forming holes or passages for the admission of air to the furnace.
When large and small coal is charged or introduced into furnaces
indiscriminately mixed together, as heretofore practiced, the small picces
fill up the interstices between the larger ones and thus prevent the free
passage of air through the fuel from between the bars which soon
become choked with clinkers, thereby causing imperfect combustion,
necessitating the pricking, slicing, and breaking up of the fire to clear
the
spaces between the bars and thus obtain a free draught again.
In order to obviate this difficulty I first separate the coal into three
classes, large, medium, and small, the fire boing first made with medium
sized lumps of coal to commenco with, and owing to the narrow spaces
or small openings between the bars in accordance with my improvements
the large coal spread thereon will soon produce a clear and uniform fire
throughout the furnace. I then spread or distribute a thin layer of
the medium sized coal over the surface of the well ignited fuel, and
when the fuel is in a perfectly clear incandescent state the smaller coal
can be introduced and distributed over the surface in small quantities at
a time, by which means it can be readily and perfectly consumed
without the production of smoke.
As the body of the fire requires to be replenished I regulate and turn
over the front portion towards the middle and back of the furnace,
taking care not to break up the lumps more than can be avoided. I
then charge the front portion of the fire-bars thus cleared with the
largest lumps of coal, and as the gases are evolved therefrom they are
consumed in their passage over the live or incandescent fuel towards the
middle and back of the furnace, and when the fuel is perfectly clear I
introduce the medium sized pieces of coal in small quantities at a time
distributed carefully over the surface of the incandescent fuel as
previously described.
When there is more than one furnace chamber to a boiler or series of
boilers, I prefer to charge one or more of such furnace chambers with
the lump and medium sized coal only, the bars being arranged with very
narrow spaces as previously described, and the small coal and nuts or
slack is consumed in another chamber the firc-bars of which are
arranged the same as in existing furnaces.

page_text: When charging or feeding either of such furnaces with fresh coal I
first force the well ignited fuel towards the middle and back of the
furnace, and place the fresh coal in the front nearest the doors, as
previously described.
In applying my improvements to locomotive furnaces I separate from
the ordinary description of coal employed from 20 to 25 per cent. of the
small coal and nuts, and where the small coal cannot be consumed to
advantage I use the lumps and medium only for consumption in
locomotive furnaces. By this means much more steam can be raised
without the small coal by reducing the spaces between the bars to suit
the combustion of the lump and medium sized coal thus employed,
whereby smoke may be prevented and the formation of clinkers to a
great extent avoided.
In applying my improvements to a baker's furnace in first lighting the
fire I prefer to get it up with small coal and the best of the waste before
putting on good coal. When this is well ignited I charge or feed the
furnace with medium sized coal, and when this is well ignited I remove
or force the fire away from the door with a regulator or driver which
prevents the smoke from escaping to the chimney. I next charge with
larger coal, keeping it nearest the door, and as it becomes well ignited
then charge lightly with medium sized coal, and so on in successive
order as before described.
When large lumps of coal require to be broken they should be sliced
with a chopping tool in the direction of the length of the grain of the
coal, in place of breaking the grain transversely with a hammer or
otherwise. By this method of breaking the large lumps much waste will
be avoided, and the coal will burn more advantageously.