also Applicable to Gas Producers.
Year: 1885

page_text: also Applicable to Gas Producers.
I JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN FURNACES FOR BURNING PULVERULENT MATERIALS ALSO APPLICABLE
TO GAS PRODUCERS" which has been communicated to me from abroad by Michel
Perret of Paris in the republic of France Manufacturer to be as follows:-
In furnaces constructed according to this Invention the products of combustion
are caused to circulate through a mass of pulverulent fuel which descends gradually
from the upper to the lower part of the furnace being supported on a series of
arched horizontal bars or narrow shelves of fireclay arranged baffle-wise so that
the piles of fuel formed thereon constitute with the sides of the said shelves a series
of natural channels or flues for the passage of the air and products of combustion.
The horizontal bars or shelves may be made hollow and utilised as retorts for
distilling coal, revivifying animal charcoal or reducing roasting or otherwise treating
various materials.
The furnace is provided at its upper part with a charging door or hopper and an
opening for the escape of the products of combustion. At the lower part there is a
sole or ashpit for the reception of the exhausted fuel.
The front of the furnace is preferably formed of cast iron plates having as many
small hinged doors as there are natural flues formed in the combustible mass
between the piles which are formed by the fuel in falling and the under surface of
the bars or shelves which are made of a trapezoidal prismatic shape in cross section
with a flat top and inclined sides. Their extremities engage with supporting ledges
of fire clay of corresponding form hollowed out at intervals in order to provide for
the circulation of the gases. A small interval is left between the ends of the bars
where they abut against the supports in order to allow for contraction and
expansion.
Thus constituted and arranged side by side so as to form shelves or stages the
bars present sufficient intervals between them for the descent of the fuel or materials
which slide down freely between the bars. The piles formed by the fuel in its

page_text: descent produce natural flues whereby the air and products of combustion are
conveyed from end to end or from side to side of the furnace in a zig zag direction
in opposite directions alternately as they ascend through the several stages in
Buccession. Suitable vertical passages at the ends or sides of the furnace connect
the different stages or series of horizontal flues. The flues can be cleared and the
descending movement of the materials facilitated if required by opening doors in
the front of the furnace and introducing a suitable tool or stirrer.
'
The fire is kindled by means of fire wood placed in the ashpit or in a grate
provided for this purpose. By opening the doors of the lower compartment the
ashes may be readily pushed with a small rake into the ashpit and the materials
are thus caused to descend from. the upper part the supply being kept up by
introducing a corresponding quantity through the charging door or hopper. The
air supply is introduced and controlled by means of doors or valves at the lower
part of the furnace or corresponding with each series of bars.
This furnace may be used as a gas producer. In this case it being necessary to
produce carbonic oxide it will suffice to regulate the admission of air so as to obtain
an incomplete combustion and to increase the number of bars.

page_text: also Applicable to Gas Producers.
I JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been com-
municated to me from abroad by Michel Perret of Paris in the Republic of France
manufacturer and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement, that is to say:
In furnaces constructed according to this invention the air and products of
combustion are caused to circulate through a mass of pulverulent fuel which
descends gradually from the upper to the lower part of the furnace being supported
on a series of horizontal bars or narrow shelves of refractory material such for
example as fire clay arranged bafflewise so that the fuel thereon constitutes with
the sides of the said shelves a series of channels or flues for the passage of the air
and products of combustion. The horizontal bars or shelves may be made hollow
and be utilised as retorts for distilling coal for revivifying animal charcoal or for
reducing or roasting or otherwise treating various materials..
The said shelves are arranged in superposed rows those of each row being
situated in vertical line with the spaces between the shelves of the adjacent row or
rows so that the spaces between the whole series of shelves form zig zag passages
down which the fuel descends gradually by sliding from one shelf to another. The
said shelves are preferably made in the form of a prism of the sectional shape
shewn in the drawing or approximately so leaving between them sufficient space
for the passage of the fuel which is introduced from time to time by means of a
door or hopper at the upper part of the furnace. These shelves are preferably
arched in the direction of their length in order that they may not collapse if they
should become cracked.
The upper sides of the shelves are formed as hereinafter described so as to support
the fuel and enable its fall to be regulated with facility as required by means of a
hooked rod or stirrer. In this furnace the materials slide down freely at all points
where required and require no raking from one end of the shelf to the other. The
air supply for supporting combustion is regulated at the lower part of the furnace
through suitable valve controlled openings and traverses the mass together with
the gaseous products of combustion in a zig-zag direction passing through the flues
formed between the undersides of the shelves and the fuel beneath.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheet of Drawings the same letters of reference
indicating corresponding parts in all the figures.
Figure 1 represents a longitudinal vertical section of a furnace, constructed
according to this Invention. i
Figure 2 represents a vertical section of the furnace taken along the line 1-2
figure.1.

page_text: Figure 3 shows a front view of the furnace partly in section along the line 3-4
figure 1 and the other Figures are details as hereinafter explained.
In this furnace the fuel descends in a zig zag direction as indicated by the arrows
in figure 2 between rows of shelves S arranged as baffles the openings between the
shelves of each row being placed underneath the shelves of the row next above.
These shelves are enclosed by solid walls M of masonry forming the sides and ends
of the furnace which is provided at its upper part with a charging door as indicated
at P or with a hopper as indicated at T figures 1 and 2 (or with both) and an
opening O for the escape of the products of combustion. At the lower part there
is a sole or hearth R serving as an ashpit for the reception of the residue of the fuel
and upon which a small quantity of wood or the like may be burned in order to
kindle the fuel and start the furnace. A special furnace or fire place of any
suitable description may be employed for this purpose if preferred. The front of
the furnace is preferably covered with cast iron plates having as many small
hinged doors t as there are flues formed between the shelves and the fuel which
collects on the shelves as the said fuel descends through the furnace. The shelves
or supports S represented separately in figures 4, 5 and 6 are made of refractory
material such as fire clay and with a flat top 8 and inclined sides S¹. The
extremities of these shelves are supported by ledges or recesses of corresponding
form in or on supports U forming partition walls provided with a number of
openings u for the circulation of the gases. These supports U consist of blocks of
the form shewn separately in figures 7 and 8. A small interval is left between the
ends of the shelves S and the supports as indicated at x figure 1 in order to allow
for contraction and expansion. These bars or shelves S are slightly arched with
the object hereinbefore explained and when arranged so as to form a series of
supports or stages they present sufficient intervals between them for the descent of
the fuel. The fuel which collects during its descent on the upper part of the
shelves produces flues at K figures 1 and 2 whereby the air and products of
combustion are directed in a zig zag direction as indicated by the arrows in
figure 1 being caused to pass in opposite directions alternately as they ascend
through the apparatus..
Passages E at the front and passages F at the back of the furnace connect the
different stages or series of flues and enable the air to follow the path indicated by
the arrows in figure 1 on its way to the opening O.
The flues can be cleared and the movement of the materials accelerated if
required by opening the doors t and inserting a suitable rake or stirrer.
The fire is readily kindled by means of firewood or the like placed in the ashpit
or lower part of the furnace R. By opening doors at p the ashes may be readily
pushed from the lower compartment into the ashpit by means of a rake and the
fuel is thus caused to descend continually from the upper to the lower part of the
furnace the supply being kept up by introducing a corresponding quantity through
the charging door P or through the hopper T.
The air supply is introduced and controlled by means of the doors or valves at p
communicating with the ash pip R or by adjustable openings arranged in any other
suitable position.
The bars or shelves S may be made hollow as indicated in figure 9. These
hollow bars communicate with the exterior of the furnace and may be employed as
retorts for treating materials requiring to be roasted torrified, distilled or reduced
for example, and present the advantage of enabling all the heat generated in the
centre of the mass of fuel to be utilised. It will be readily understood that this
arrangement of shelves forming retorts enables the improved furnace to be applied
to a great variety of manufacturing processes amongst which may be mentioned the
distillation of coal, the production or revivifying of bone black or animal charcoal
and the roasting of poor pyrites. It is evident that either the whole or part of the
shelves may be utilised as retorts and that any system of closure may be applied to
their ends. This furnace can also be used as a gas producer. In this case it being
necessary to produce carbonic oxide it will suffice to regulate the admission of air so

page_text: as to obtain an incomplete combustion of the materials and to increase the number
of bars or shelves according to the effect required. The improved furnace when
converted into a gas generator or producer by a modification in the air supply
produces combustible gases which may be conveyed away and utilised in the same
way as in ordinary gas producers.
Having now particularly described and ascertained the nature of this Inven-
tion and in what manner the same is to be performed I declare that what
I claim is
First. An improved furnace for burning pulverulent fuel provided with shelves
arranged alternately or bafflewise the said shelves being of such a form that the
pulverulent materials or fuel accumulating thereon constitute with the sides of the
shelves flues for the passage of the products of combustion and air substantially as
berein before described and illustrated in the accompanying drawings.
Second. In a furnace constructed as hereinbefore described and claimed for
burning pulverulent fuel the combination of the shelves S the supports U the
stirring doors t the charging door P (or hopper T or both) and the ashpit or sole R
substantially as hereinbefore described and illustrated in the accompanying
drawings.
Third. In combination with a furnace constructed for burning pulverulent fuel
as hereinbefore set forth the employment of hollow shelves forming retorts
substantially as hereinbefore described with reference to figure 9 of the accom-
panying drawings.
Fourth. The modified arrangement to be employed when the improved furnace
is applied to the production of combustible gases substantially as hereinbefore
described.
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