of the Coals in Steam Boiler and other Furnaces.
Year: 1887

page_text: Date of Application, 6th June, 1887.
Specification Accepted, 22nd July, 1887.
of the Coals in Steam Boiler and other Furnaces.
We, LOUIS PHILIPP COHEN and ERNEST HERRMANN, both of 30 Rue Cardinet
in the City of Paris and French Republic, Engineers, do hereby declare the nature
of our 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 to improvements in the step gratings for steam boiler and
other furnaces in order to effect an entire combustion of the coals or other combustive
material employed for heating the same, the special object or purpose of said
improvements being to considerably diminish the quantity of combustive material
hitherto necessary to attain the object in view.
By means of these improvements the products of distillation of the coals and
especially the bad combustible double carburetted hydrogen gases are intermixed
with a draft of fresh air, immediately they are developed at the commencement of
the combustion and instantaneously totally consumed by a glowing layer of coals
before any considerable quantity of gas can accumulate and so prevent the
combustion. It is a well known fact that in order to entirely consume double
carburetted hydrogen gases, it is absolutely necessary besides sufficient atmospheric
air and a sufficiently high temperature to also make provisions for separating the
saune into thin layers, which can only be done immediately after said gases have been
originated or developed by the products of distillation of the layers of coal for the
reason that it is impossible to effect a perfect combustion if the combustive materials
accumulate in thicker layers. The improved heating appliances for furnaces etc.
constituting subject of present invention are so arranged that if properly operated
the above conditions are thereby fulfilled in every respect. The device or
arrangement by means of which we are able to fulfil all the requirements mentioned
above, consists in improving the fire grate.
In the accompanying drawings.
Figure 1 is a longitudinal section of our improved furnace and
Figure 2 is partly a front view and partly a cross section of the same.
The actual fire grate composed of three different parts-i.c.
1. The upper part A serves as an extension of the feed opening or hopper and

page_text: consists substantially of vertical or horizontal fire bars, the spaces between which
serve as a means for observing the operation inside the furnace and can also be used
to advantage for removing any obstacles which could impede the free passage of the
coals.
2. The middle or intermediate part B of the grate serves to distil the coals thereby
producing the carburetted hydrogen gases, fresh air being freely admitted through
the orifices t.
3. The third or lower part C of the grate B is arranged to consume the residue
of the distilled coals such as coke etc. The said upper part A of the step grate forms,
by means of the opposite brick work, boiler surfaces, and the side walls, which are
sheathed by an iron frame, a conically shaped opening, which is kept constantly
filled by the feed opening T.
Suitable openings are arranged in the sides of the brick walls through which
air is led into the cross way D said openings may be substituted by cast iron
semi-circular pipes or tubes, the position of which can be altered or changed at will.
The grate B is movably arranged on the shaft and forms in conjunction with the
opposite wall of fireproof bricks a conical passage canal or opening, said grate B
being generally in such a position that the coals or other combustible material resting
thereon, close the opening or entrance to said conical space. By this means the
gases, which are generated on the grate B, will be caused to follow the course of
the draft and so forced to take their way through the burning layer of combustive
material.
As hereby always a certain quantity of fresh atmospheric air is drawn or sucked
in through the openings t, the perfect combustion of the combustible hydrogen gases,
will be ensured, which is very difficult to attain with the apparatus or appliances at
present in use. After the preliminary combustion or burning is in a sufficiently
advanced or completed stage, which can be readily observed, through the openings
or spaces between the bars of the movable part A, the coals are allowed to fall to the
bottom by shaking the lever ², The high degree of temperature which it is
necessary to attain in order to obtain good results is ensured by means of the
hydrogen gases, being originated or generated and consumed at one and the same
place, that is, on the grate B.
After the treatment of the coal on grate B said coal or other combustive material
is allowed to drop or fall on to the lowermost grate C, where the perfect combustion
of the same is effectuated under such favorable circumstances that a deposit of slag
or cinders is found in only the deepest parts of the grate, but even this slag
formation is so very diminutive in quantity as to represent barely the fifth part of the
residue which would have remained if the same quantity of coal had been treated on
an ordinary horizontal fire grate.
This lowermost step grate C is also movably arranged on the spindle or axis c, c,
on which the fire bars rest, by means of their lower hooks, said fire bars being
supported at their upper ends by a cross sleeper or U shaped rail U, which is
movably arranged on the shaft N, by means of the arms v. By suitably changing
the position of the cross bar or sleeper U, by means of the toothed segment w and
worm a it is possible to bring the layers of coal on the grate C into any desired
position; said grate C can furthermore be brought into the position represented by
dotted lines in Fig. 1 for cleansing purposes and to readily ignite the fire. In order
to be able to independently regulate the entrance of fresh air to the grate B as well
as to the lower grate we arrange a small partition walls between same. The draft
necessary for the distilling operation is regulated by the slide t, which is provided
with suitable openings, whereas we arrange two Rosettes t¹ to regulate the entrance
of fresh air to the lower grate, where the perfect combustion of the coals is effected.
Grate B is provided with a suitable counter-weight or balance G, to always retain
same in closed position so as to exclude the possibility of its being shifted in
consequence of its own weight or the weight of the coals thereon.
The advantage offered by our improved step grate furnace, even when compared
with the most perfect furnaces operated by continual charging at present in use will be

page_text: found to be very considerable as even the small quantity of smoke which is noticed
a short time after charging other furnaces, either direct or indirectly on to the grate
is absolutely prevented by the employment of our improvements.
One great advantage consists in igniting the gases, by means of a burning layer
or layers of coal instead of by burning gases under the influence of a strong draft
as it is quite impossible with the latter method to effect a perfect combustion. By
means of this advantage we are placed in a position to effect the combustion with a
minimum quantity of air, entirely prevent the influx of too large quantities of air,
greatly decrease the cooling of the fire, and loss of heat through the chimney or
funnel.
A further advantage of our improved furnace, is that any kind of coal can be
burnt therein as only the width or breadth of the charging opening has to be altered,
to suit combustible materials of any dimensions. The capacity of the aforesaid
furnace can be greatly varied if desired by appropriately adjusting the lower grate C
and correspondingly regulating the charging opening or hopper.
Having now particularly described and ascertained the nature of our said invention
and in what manner same is to be performed we declare that what we claim and
desire to secure by Letters Patent is :-
A step grate furnace of the kind herein described for effecting the perfect
combustion of coals, applicable to steam boilers as well as to other heating arrange-
ments, said furnace consisting of,
1. The application arrangement or employment of the charging hopper T, which
receives the coals, from above and leads the latter and the products of distillation,
downwards said hopper T consisting of a rigid upper part or jaw of fire proof bricks
and a movable jaw, which is composed of grate A, substantially as described.
2. The production in layers of coal of hollow spaces, having a suitable air influx
by employing the natural incline of the coals by means of excavations in the brick
wall or suitably arranged cross sleepers or U shaped rails U, substantially as
described.
3. The arrangement application and employment of an inclined movable grate C
for altering the thickness of the layers of coals said grate C being raised and lowered
by means of toothed segment w and worm a, substantially as described in the
foregoing specification.
ALLISON BROS.,
Agents for the Applicants.