Improvements in Furnaces or Fireplaces for Burning Pulverulent Materials.
Year: 1887

page_text: Date of Application, 29th Dec., 1887
Complete Specification Left, 22nd Sept., 1888
Complete Specification Accepted, 26th Oct., 1888
PROVISIONAL SPECIFICATION.
Improvements in Furnaces or Fireplaces for Burning Pulverulent
Materials.
I, BENJAMIN WILLCOX of 47 Lincolns Inn Fields in the County of Middlesex
Patent Agent do hereby declare the nature of this Invention which has been com-
municated to me from abroad by Michel Perret of Paris in the Repubic of France,
Manufacturer to be as follows:-
This Invention relating to furnaces or fireplaces for burning pulverulent materials
consists in an improved arrangement of the supports on which the materials are burned
whereby a large area of surface is exposed to the action of the air and the combustion
is thereby accelerated as hereinafter explained.
In a furnace or fireplace constructed according to this Invention the combustible
materials are supported on a series of horizontal shelves or partitions presenting
numerous holes through which the materials can fall. The holes in each shelf are
situated over solid parts in the shelf or partition immediately beneath it so that as the
material falls through the holes in the upper shelf it forms a number of conical
or pyramidal piles or heaps on the under shelf. The under shelf being similarly
provided with holes distributes the materials in like manner to the shelf next beneath
it and the materials are thus caused to fall from shelf to shelf until they reach the
ash pit at the lower part of the apparatus.
The air to support combustion is caused to circulate in a zig zag direction through
the structure so as to pass between the conical heaps or piles on each shelf or horizontal
partition suitable doors or valves being provided to control or regulate the supply.
The furnace may be surrounded by a casing or jacket which may be utilized for
heating air and prevents the sides of the furnace from being chilled. Any convenient
number of shelves or horizontal partitions may be employed and unperforated or solid
shelves may be provided at suitable intervals when it is desired to keep certain of the
materials separate from the others. The number of holes in each shelf or partition
and the vertical distance between the shelves or partitions is regulated according to
their position in the apparatus and the condition or nature of the materials.
Dated this 29th day of December 1887.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C.,
Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Furnaces or Fireplaces for Burning Pulverulent
Materials.
I BENJAMIN WILLCOX of 47, Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been communi-
cated to me from abroad by Michel l'erret 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:-
This Invention relating to furnaces or fireplaces for burning pulverulent materials
consists in an improved arrangement of the supports on which the materials are
burned whereby a large area of surface is exposed to the action of the air and the
combustion is thereby accelerated as hereinafter explained.
The combustion of pulverulent or dusty fuel upon solid surfaces in furnaces with
horizontal partitions or shelves as heretofore constructed presents the disadvantage of
involving a considerable amount of labor in drawing the fuel from one shelf to another
and spreading it on the shelves.
To obviate this difficulty the weight of the fuel itself is utilised according to this
invention for causing it to descend from one shelf to another and this object is attained
by means of an arrangement hereinafter described wherein a vacant or hollow space
is left between the sides of cones or heaps down which the dusty or pulverulent matter
rolls. A slight movement or disturbance with a rake or poker is sufficient to cause
the fuel to descend without effort and the air and gases circulate about the surfaces of
the heaps as in a furnace with solid shelves.
In both of these systems the air acts on the surface only of the fuel and the com-
bustion owing to the small extent of this surface is not very active and in fact it is
not possible to burn with advantage more than about two kilogrammes of fuel per
hour and per square metre of surface exposed to the air which merely glides horizontally
along this surface.
The combustion of fragments or lumps of fuel upon a grate proceeds under entirely
different conditions. The air surrounds each fragment or lump which presents say
six or more sides to the action of the air in the case of lumps in the form of cubes for
example and aboni. 60 kilogrammes of fuel per hour and per square metre can thus be
burned with facility. Moreover the direction of the air being continually changed in
order to pass between the lumps the gases are caused to impinge on the solid parts
with a force in proportion to the speed of the gas resulting from the contraction of
the passages between the lumps. The reaction of a gaseous body on a solid body is
greatly promoted by this impact as in a forge fire for example.
In order to obtain with pulverulent fuel conditions approaching as nearly as possiblo
to those under which the solid fuel is burned on a grate as aforesaid it is necessary to
subdivide the pulverulent matter without previous preparation. This is accomplished
to a certain extent by means of the present invention as hereinafter described.
The furnace is constructed with horizontal partitions arranged one over the other as
in a furnace with shelves but with the important difference that the partitions are
perforated in such a manner that when the combustible material is thrown on to

page_text: the upper shelf or partition it falls through the holes and covers all the shelves in
succession forming underneath each opening a small heap or cone of a form corresponding
to that of the opening.
The size of the openings, their shape and their position relatively to one another
are calculated in such a manner as to leave between the heaps spaces or intervals
sufficient for the passage of air. By arranging the holes in the form of a quincunx
or so that the openings between one series of heaps are placed opposite the solid parts
of the next series the air and gases are caused to impinge against the sides of the
heaps of fuel. The heaps tend to shrink or diminish in size as they burn away but
the loss is continually made up or compensated by fresh fuel descending from the
shelf above so that the action is rendered uniform and continuous so long as the supply
of material is kept up.
The furnace is charged in a similar way to a furnace with ordinary or unperforated
shelves but it is sufficient to pass a rake or poker over or through the conical heaps so
as to disturb them in order to cause the fuel to pass from one shelf to another forming
heaps on each shelf automatically and with perfect regularity without the intervention
of any special tool or instrument, the arrangement of the orifices being such that the
holes or openings in each shelf are placed over the solid parts of the shelf next
beneath it. The lower shelf may be entirely cleared in order to maintain separate
the materials on different shelves in order to obtain ashes entirely free from com-
bustible matter for example. This advantage has heretofore been obtained by means
of furnaces divided into separate compartments.
And in order that my 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 sheets of drawings the same letters of reference indicating
corresponding parts in all the figures.
Figure 1 of the accompanying drawings represents in longitudinal vertical section
a furnace constructed according to this invention.
Figure 2 represents the furnace in transverse section and Figure 3 in horizontal
section.
This furnace is constructed with walls M of brickwork or masonry enclosing a series
of shelves or horizontal partitions A A¹ and an ash pit B at the lower part. The
front wall is provided with openings CCC formed in a cast iron plate P and capable
of being closed by hinged doors. The fuel is introduced through the opening and
placed on the upper shelf whence it passes to the lower shelves in succession and the
resulting ash being received in the ash pit at the bottom. Each shelf with the
exception of the bottom shelf A is perforated with openings a through which the
pulverulent fuel falls and forms upon the shelf next beneath it a corresponding
number of separate heaps with sloping sides.
The said openings or holes a are arranged quincuncially in each shelf as indicated
in the plan, figure 3 of the drawing, their number, their sectional area and the
interval between them being regulated according to the nature of the combustible.
In all cases they are so arranged that each opening corresponds with a solid part
on the shelf below. The effect of this arrangement is that on each shelf there are
formed as many separate heaps as there are openings or holes in the shelf
above and each heap assumes a conical form. Another result of the arrange-
ment is that the air or gas supporting combustion is caused to circulate around
the heaps on all sides and to impinge against them and consequently to deeply
penetrate the combustible material which under these conditions burns more
actively than it would do if the air simply glided over its surface. The vertical
distance between the shelves is greater at the upper part and gradually diminishes
towards the lower part.
According to the arrangement illustrated in figures 1, 2 and 3 the furnace is
surrounded by an outer casing E forming a heating chamber D in the space between
this outer casing and the sides or walls M of the furnace. The air required to support
combustion is introduced through and the supply is regulated by doors adapted to the
openings CCC the air circulating from one shelf to another by passing through

page_text: openings Varranged alternately at opposite ends of the furnace. The products of
combustion escape at the upper part of the furnace through a flue or chimney T
which conducts them to the place where they are required and the ash is withdrawn
through the opening C².
Figures 5, 6 and 7 illustrate in transverse, longitudinal and horizontal section
respectively a furnace according to this invention in which the walls M are made as
thin as possible and are lined with fire-proof or refractory slabs or tiles m provided at
the sides of the furnace with projections or ledges n supporting the perforated
shelves A. The said walls are covered externally with a casing composed of plates b
connected at the corners by angle irons and strengthened where necessary by bars
of iron of suitable section. This reduction of the walls is on account of the high
temperature produced in the furnace and the continuous metal casing is employed for
the purpose of preventing accidental admission of air at the same time ensuring the
preservation of the apparatus as is commonly practiced in the construction of furnaces
which are provided with a metal casing with the object of supporting the sides or
in which the sides are made of metal with a refractory lining. Any suitable materials
or composition may be employed to construct the thin walls and wrought or cast iron
or tiles alone or in combination may be employed to form the outer casing.
In the furnace illustrated in figures 5, 6 and 7 the number of the perforated
shelves A is reduced to two in consequence of the active or rapid combustion
resulting from the divided condition of the materials the cost of construction and
labor in building the furnace being likewise diminished. These shelves are arranged
at equal distances apart. The number of holes or openings a is not the same in both
shelves being smaller in the lower shelf than in the upper. This arrangement being
necessary when the furnace is supplied with fuel which shrinks or diminishes in
volume under combustion in order to obtain an approximately uniform distribution of
the material on the separate shelves and at the same time provide sufficient space for
working the materials between the shelves.
At the rear of the upper shelf there is a raised part or bench S in which are formed
openings for the escape of the products of combustion which have circulated about
and penetrated the heaps on the lower shelf. The object of this raised part is to
provide a passage for the escape of the gases that will not be liable to be choked with
the fuel which is thus prevented from falling to the unperforated rear portion of the
lower shelf.
Figure 4 illustrates in plan the principle on which the heaps are distributed on the
shelves in the furnace represented in figures 1, 2 and 3 and figure 8 similarly
illustrates the arrangement of the heaps in the furnace represented in figures 5,
6 and 7. As indicated by these figures 4 and 8 (and figures 2 and 6) the fuel
does not present a flat horizontal surface to the action of the air and gases as in
the ordinary arrangements but exposes a series of inclined or conical surfaces with
the openings between the heaps in one line of heaps arranged opposite the heaps
in the next line so as to compel the streams of air and gases to follow sinuous
paths as indicated by the arrows x and y and impinge against all the heaps in
succession.
The materials are caused to descend through the furnace by stirring the heaps
with a suitable tool or hooked instrument so as to cause them to fall through the
openings and form heaps on the next shelf. With this object the burned materials
on the bottom shelf A' are first raked into the ash pit after which the heaps on the
lowest perforated shelf A are raked down through the perforations on to the bottom
shelf and so on thus working upwards until the top shelf is cleared and a new charge
may then be placed on this shelf. Considerable intervals of time may be allowed to
pass between each charging operation as the lower heaps are fed or supplied auto-
matically from the upper heaps in proportion as they tend to diminish in volume
owing to the combustion. In the case of materials that are not reduced in volume by
combustion such as pyrites, certain anthracites, furnace residues etc., which produce a
large volume of ash or cinder the operation requires to be repeated more frequently
in order to induce the materials to descend..

page_text: In either case the furnace with the perforated shelves possesses considerable
advantages compared to a furnace with solid shelves in which the materials in
order to pass from one shelf to another require to be moved more frequently and pro-
longed exertion is required for moving the materials over the entire length of each
shelf in order to cause it to fall onto the next shelf where it has to be spread anew in
a regular layer. Moreover as the mass of material undergoing combustion at one
time is more considerable in the furnaces with perforated shelves the materials are
enabled to remain a longer time in the furnace and the operation does not require to
he so often repeated on the same materials. The cost of the labor which is con-
siderable in working pyrites furnaces of this description as heretofore constructed is
thus materially diminished.
It is evident that the details of construction may be modified in various ways
without departing from the spirit of the invention which is not limited to the par-
ticular form of construction illustrated in the accompanying drawings which are
merely given as examples of the best modes with which I am acquainted for carrying
out the invention in practice. For example I do not limit myself as to the number of
shelves, the number, form and arrangement of the perforations or openings a, the
construction and thickness of the brickwork or walls M. its tight and heat retaining
envelope or the number and arrangement of the working holes C. The form of the
front plate and the employment of a hot chamber D surrounding the sides and other
details are also optional and can be varied or omitted according to circumstances and
the purposes such as heating air, treating pyrites or other minerals for example to
which the furnace may be applied.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a furnace for burning pulverulent materials dividing or distributing the
combustible matter upon perforated shelves (A) provided with perforations (a) or
equivalent means whereby the said matter is caused to descend and arrange itself
automatically in the form of a series of independent conical heaps arranged as herein-
before set forth or in such a manner that the gaseous agent supporting combustion is
compelled to circulate around and impinge against the said heaps all substantially as
hereinbefore described.
2. In a furnace with perforated shelves the arrangement of the shelves A placed
nearer together at the lower than at the upper part of the furnace and presenting
perforations a regularly distributed quincuncially in combination with an ash pit B
openings C, CC for the admission of air and passages V for the circulation of the
gases substantially as and for the purpose herein before described with reference to
figures 1, 2 and 3 of the accompanying drawings.
3. In a furnace with perforated shelves the arrangement of the equidistant shelves A.
provided with perforations a the said perforations being less numerous in the lower
shelf than in the upper shelf in combination with a projecting or raised part or bench S,
an ash pit B. openings C, passages V, and a brickwork or other casing M substantially
as hereinbefore described with reference to figures 4, 5 and 6 of the accompanying
drawings.
DL1
33 11
C 5
1
1000