Improvements in Fire-boxes.
Year: 1890

page_text: Date of Application, 30th Dec., 1890-Accepted, 7th Feb., 1891
COMPLETE SPECIFICATION.
Improvements in Fire-boxes.
I, JOSEPH C. HENDERSON of 195 River Street, Troy, County of Rensselaer,
State of New York, United States of America, Manufacturer, 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 consists of a revolving fire-box in combination with the combustion
chamber of any stove or furnace, as hereinafter described and claimed.
The objects of my invention are to effect a thorough combustion of the gases
arising from the freshly supplied and consuming coals, a thorough and economical
consumption of fuel, and to maintain a constant hot bright fire at the top of the
fire-box.
It is well known that in supplying coal to the top of a fire within a stove or
furnace the effect is to cover the fire, and temporarily subdue it, and to decrease
materially the temperature by the absorption of heat by the fresh coals, and that
some time is necessarily occupied before the fresh fiel is ignited, and the desired
high temperature is obtained, while in the meantime the light gases formed from
the fresh layer of fuel are unconsumed and carried away. The bad results from
this ordinary method of burning coal, are a diminution of temperature often just
when a high temperature is most needed, and great delay in cooking or heating,
and the production of a constantly variable temperature.
The means by which I overcome these objections, and which constitute my
invention, are illustrated in one form in the accompanying drawings, in which
Fig. 1 is a view in perspective of my improved fire-box, and its connections with an
adjoining casting and a grate, and Fig. 2 is a view in elevation partly in section,
of the same.
In the drawings the fire-box or chamber is shown as composed of two equal
curved plates E E joined to a head A at each end, and having between them an
opposite top and bottom opening for the insertion of fuel, and to afford communi-
cation with the grate.
The box is supported and revolves on trunnions D on the heads A which pass
through, and are supported by the outside casing. The fire-box can be lined with
fire-brick. B B B are curved plates at the front and rear of the box to form a
cylindrical chamber in which the box revolves. This chamber may be formed as
shown, or may be of plates, or parts detached from the casing. It will be noticed
that the chamber is so separated from the fire-box as to form a space, h, around or
on both sides of the box, between it and the casing. The functions of this space
are to avoid friction between box and chamber, to afford room for the expansion of
the box, to constitute an air space around the box to prevent its destruction by
over heat, and what is more important, to provide passages for conducting the gases
evolved from the fresh fuel at the bottom of the box, to the top of the same, where,
meeting the live or incandescent fuel, they are consumed, thereby adding to the
heat of the fire, and at the same time by their increased force and combustion
increasing and maintaining the draught.
The gases and air it will also be noticed are highly heated in their course up the
said passages thereby adding to their volatilized condition and combustibility.
C is a grate beneath the fire-box. The form of such grate must be circular to
allow the cylinder to revolve within the box which the grate helps to form.
Fare lugs on the heads A. of the fire-box which meet corresponding lugs F1
on the casting, so that when the box is revolved after the admission of fresh fuel it
is given but half a turn.
When the cylindrical fire-chamber is supplied with fresh fuel it is turned by
means of a crank applied to a trunnion and the fuel on top is turned down on
1

page_text: the grate below, and the burning fuel is brought to the top. The grate is revolved
to clear off the ashes which adds to the draught, a bright fire is maintained on top,
while the gases evolved from the bottom by the heat pass through the fire and are
more perfectly consumed. The highly heated air circulating upward through the
spaces between the fire-box and outer casing carries with it the volatile gases,
and the curved walls of the fire-box carries these gases from opposite directions
directly over and into the top fire where they are consumed and add to the heat
and brightness of the fire at that point.
In order that the hot volatile gases escaping from the grate should pass into the
side spaces or passages described it is necessary that those passages should connect
directly with the mass of fresher fuel on the floor of and within the grate and
that such passages should be unobstructed and so constructed that the heated gases
should pass directly over and with full force on to the top of the incandescent fuel.
The unconsumed gases meeting and mixing with the gases arising from the
incandescent fuel a fresher fire and a strong draught is at once commenced and main-
tained at the top of the fuel.
I am aware that revolving grates, like that of Dr. Franklin's, have been used to
turn the fresh coal to the top and the live coal to the bottom, and that partially
revolving and perpendicularly moving fire-boxes or barrels have been also invented
for the same purpose, but it will be noticed that in such cases the same have been
open on all sides to the outer air, or rotated and revolved in an open air space,
which operation I have found objectionable and impracticable in the matter of
consuming the gases and maintaining perfect draught and combustion.
I am also aware that revolving fire-boxes have been constructed with spaces
between the sides of the box and the casing but with such spaces closed by flanges
extending from the sides of the fire-box the function of said Hanges being to hold
and scrape down any ashes or pieces of coal that may get in between the fire-box
and the case. I am further aware that it is old in stoves to form a space back of
the grate and between it and the case which leads the outside air from the box
below the grate, heats it, and discharges the heated air into the top of the grate,
but in such case does not lead the gases from the bottom of the bed of unignited
fuel within and above the grate, but only air from the outside. And I do not
therefore claim broadly any of the single features of a revolving fire-box, or such a
box having air spaces around it.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare what I
claim is :-
1. A cylindrical fire-box having opposite openings, in combination with a
surrounding cylindrical casing, said casing separated from the fire-box so as to form
enclosed but unobstructed passages on both sides of the fire-box which com-
municates with said opposite openings, and a grate beneath said box and separated
therefrom, whereby room for the expansion of the box is secured, and air and gases
from the bottom opening are conducted through said passages to the upper opening
and projected from both sides across the chamber over the top of the fire and
thoroughly mixed therewith, substantially as described.
2. In combination with the cylindrical revolving fire-box, the cylindrical casing,
and the circular revolving grate, the walls of the said box entirely separated
and disconnected from said casing and grate and located above the grate, the said
grate also separated from said casing but on a line therewith, and means for
revolving said grate and box independently of each other, substantially as and for
the purpose described.
Dated this 30th day of December 1890.
J. C. HENDERSON,
By L. W., per F. B.