Year: 1898

page_text: I, ALBERT PIAT, of 15, Rue des Halles, Paris, France, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
1
This invention relates to a new and improved furnace designed for rapidly
and economically melting metals and if required, ores, the arrangement being
such as to enable the said furnace to be constructed and repairs thereof effected
under easy and economical conditions.
To enable the nature of my improved furnace (which is capable of operating
as a cupola crucible), to be clearly understood I refer to the two annexed sheets
of drawings whereof:-
Fig. 1 is a vertical section upon the axis of the furnace on the line 1-2 and
on the line 121 31 Fig. 2 and showing the fire-place.
Fig. 2 is a horizontal section on the line 10-11 of Fig. 1 and a view in plan
of the fuel distributor.
Fig. 3 is an elevation on a smaller scale of the furnace combined with an
adjacent column, which allows of separating and moving the several principal
parts, as will be hereinafter described.
Fig. 4 is a view in plan of the general arrangement shown in Fig. 3.
Fig. 5 is a horizontal section on a larger scale of the column for separating
the various parts of the furnace.
Fig. 6 is an elevation partly in section on the line 12-13 of Fig. 7. It is
partly broken away, to show the tubular projection by means of which the
tapping is effected and it also shows the plug which serves to open and close the
tap-hole m¹.
Fig. 7 is a plan of the said plug.
Fig. S is a horizontal section of the furnace on the line 4-5 of Fig. 1.
Figs. 9 are a horizontal section immediately above the grate, and its foundation
and an elevation thereof.
Fig. 10 is a section on the line 6-7 of Fig. 1.
Fig. 11 is a section on the line 8-9 of Fig. 10.
Fig. 12 is a vertical section on the line TV of Fig. 14, showing a modifi-
cation of the device for distributing fuel to the finantaan

page_text: Fig. 13 is a section on the line N-O of Fig. 12.
Fig. 14 is a section on the line P-Q of Fig. 13.
In the several kinds of furnaces the subjects of my previous patents, the
object attained has been the realization of considerable economy, both taking
into account the time employed for melting a given quantity of metal and also
the amount of fuel which it has been necessary to burn to effect the said melting.
With such furnaces, have succeeded in melting 100 kilos. of bronze (this
metal being taken as a type) in half an hour by means of 13 to 15 per cent. of
its weight of coke and the quality of the metal has not been depreciated in.
any way.
Another difficulty had, however, to be overcome, namely, the great consumption
of plumbago relatively to the parts which plumbago had hithereto been indis-
pensable for, both for the manufacture of the crucible designed to contain the
metal, and also for the manufacture of the part known as the extension. The
invention hereinafter described has for its objects (among other advantages)
to allow of dispensing completely with crucibles and extensions made solely of
this expensive material plumbago (which is especially important when the
furnaces are of considerable dimensions) thus effecting a considerable economy
and also allowing of a more practical use of the furnaces, especially in places
where it is not possible to readily procure articles made of plumbago, which
are not only expensive but very liable to be broken in transit."
It is usually casier in such places to obtain articles made of refractory earth
which even if of special forms, may readily be moulded.
In the construction of my new furnace, the broad principle indicated in my
former Patents may be adhered to, that is to say, the portability, the swivelling,
and the pouring of metal through a gutter or channel leading from a tap, by
means of a plug which may be withdrawn from the spout of the crucible.
These apparatus are known and need not be described anew in this specifi-
cation in which it is more advisable to specially show and describe the new forms
and arrangements which have been given to the furnace which offer, in ad-
dition to economy of time and fuel (as previously stated) other advantages here-
inafter named:-
1. The possibility of doing away with the crucibles proper and of replacing
them by a receiver constructed of refractory earth, (of dimensions varying
according to the size of the furnaces); the materials employed being very in-
expensive and the parts made with said materials being highly resistant to
heat and wear and tear, and also adapted for ready renewal or repair.
2. Facility for obtaining melted metal, free from flowing slag, as exists in
cupolas designed for melting cast iron.
8. The possibility (in the case of alloys of brass), of stopping the tap-hole by
means of a plug of pure metal which may be lined with refractory earth, said
plug being either entirely independent of the furnace, or being attached to some
arrangement fixed on the furnace itself.
4. The facility of feeding the fire-place with fuel, gradually while preventing
all danger of the metal oxidizing or the introduction of cold air into the
furnace although the feeding of fuel is effected laterally whilst the blast is on.
The coke being charged into the fire-place in any desired small quantities,
becomes ignited gradually and does not cool the incandescent mass.
5. The possibility of melting cast iron and steel solely by the direct action of
the heat of the flame avoiding contact between the metal to be melted and the
fuel which latter may be more or less pure.
6. The possibility of being able to employ not exclusively coke but other fuels
such as certain kinds of coal, wood, or even liquid hydrocarbons.
7. The facility for cleaning the grate and the better distribution of fuel
obtained by the inclination of the fire bars of the same.
8. The economical utilization of the fuel employed, the said fuel being burned
under the most advantageous conditions.

page_text: 9. Obtaining a much longer life for the fittings, or linings, (even when they
are made solely of refractory earth) by reason of their not being in immediate
contact with coke except only at points situated exclusively above the fire-place
and where the parts may be made of pure silica.
The main advantages of the new furnace being thus set forth, I will now pro-
ceed to describe all the various parts with reference to the figures and the
reference letters on the annexed drawings. A is the fire place proper, of round.
square or polygonal shape, and constructed of refractory bricks. The grate a
of the same is inclined in order to effect a good distribution of the fuel which
falls with some momentum through the duct B. A is a hole formed in the
width of the furnace, for the purpose of facilitating the cleaning of the grate
from below.
A metal plate serves to close this hole during the working of the furnace.
The furnace is terminated at its upper part by a domed or arched part in
which are formed a central aperture C, and apertures ell, ell. The aperture
serves as a passage for the ignited products of combustion, which impinge
against the bottom of the crucible D and then pass through the apertures c¹ so
as to rejoin in the passages the gases that rise up through the apertures cll
and lick the outside of the crucible. The space E which is comprised between
the crucible and the lining of the furnace is reduced to a minimum and into
this space there extend projectious d', d, which serve as baffles to retard the
ascending gases.
The above-mentioned duct B is lined internally with a refractory earth and
is provided with two sliding doors or registers which are also of refractory
material. A hopper is provided to contain the quantity of fuel which it
is desired to introduce at one time in the furnace.
The door being opened, the quantity of fuel just mentioned is introduced
into the duct B, whereupon the door b is closed, and the door opened, and
in this manner, the fuel is supplied to the fireplace without introduction of air
and without escape of flame.
This system of feeding the fuel may be replaced by the arrangement shewn
in Figs. 12, 13 and 14, which may work in a continuous or more gradual manner,
the feed being effected by means of an Archimedean screw, as will be readily
understood.
The crucible D may be made wholly of plumbago, in one or more pieces, or
it may be composed of circular elements of refractory materials, fitted together
by means of tongues as shewn in Fig. 1. Or it may be made of such refractory
materials, in one single rammed piece. These elements shewn in the form of
rings, have lugs which project into the space E, and which have an outer
diameter equal to the internal diameter of the furnace. These lugs are crossed
so as to form baffles for the products of combustion, and retarding their escape:
furthermore they aid in preventing any possible bursting of the crucibles.
The first ring is a special form, and constitutes the bottom of the crucible 1).
It has a socket (Fig. 6) in which is formed the hole through which the melted
metal can run out.
This ring, which is the part of the crucible which is most exposed, may be
made of plumbago, the upper elements being of refractory earth.
The flames, after having passed up through the apertures C and c, and having
enveloped the crucible D, pass through the apertures F, of which any desired
number may be provided. The apertures may in some cases be replaced by a
single circular aperture or zone.
In this manner, the gases not only heat the crucible D, but also and especially
they, during their passage through the apertures F, aid in melting the metal
which is situated in the crucible D at the commencement of the operation, and
which is placed upon a few pieces of coke, that lie in the bottom of the crucible.
This lining of the bottom of the crucible with a little coke may be effected
either by making the aperture G of sufficient diameter for the purpose, or if

page_text: the said aperture is too small, the operation can be effected by means of a column
by which the upper part can be lifted and moved away.
"The flames, in addition to circulating between the top of the crucible I) and
the bottom of the extension II, may also rise through the orifices G¹, which are
provided to the number of 4 or 6 or more, and the said flames thus heat and melt
by direct action, the metal which is placed during the operation into the said
extension H. The extension can either be constructed of several parts or of
one single piece of refractory earth, and being arranged directly above and in
the axis of the furnace the walls of which are continued above those of the said
extension constitute a sort of furnace which may be called a cupola crucible.
Above the crucible D which collects and reheats the melted metal, is arranged
the upward extension H, in several pieces. This extension is in the bottom
piece pierced at the centre with an orifice G through which the metal escapes
that has been melted or is to be melted, and rests, by means of feet, on the upper
part of the crucible, in such a manner as to form between it and this upper part
of the crucible, the zone of openings F, F through which the flames pass and
escape in part through the central orifice.
Towards the middle of its height the extension is pierced with lateral open-
ings, G, G, through which the flames penetrate into the interior and there bathe
and reheat the metal which has descended or which descends from the throat R.
There exist also at the upper edge of the same extension, other openings through
which a part of the flames can still escape through the throat. A light cover 1°
of refractory earth closes the whole, whilst allowing the products of combustion
to escape, in such a manner that it retards them only so as to produce a slight
pressure of the gases inside the furnace.
There is thus effected by this arrangement:-
1. An intense heating of the crucible D by the flames which are also able to
reach its contents.
2. The direct action of said flames (by reason of their introduction through
the holes or the zone F and the passages G) in the extension H by licking or
enveloping the material contained therein.
3. Finally the action of the said flames also upon the metal piled in the ex-
tension passage or mouth R, in such a manner as to aid to fuse the same by
means of the extension H.
Thus there is effected the best utilization of the heat contained in these flames
whilst all contact with the fuel is avoided.
I (Fig. 6) is the plug which is jointed at J and which serves (in the case of
melting bronze especially) for closing the outlet orifice for the metal. Any
other arrangement may be employed, so long as the foundryman is protected
from jets of molten metal.
K is an aperture formed in the top of the crucible, and connected through a
small passage to the exterior of the furnace, in such a manner as to allow the
floating slag to flow out. This aperture is closed externally by means of a
plug of refractory earth during the working of the furnace. It is unstopped
in order to give issue to the flames when it is desired to heat the metal after
having removed the extension and covered the crucible.
are spy-holes, which allow of observing the behaviour of the fuel on the
grate, and of probing it for the purpose of spreading it out, if necessary.
The new crucible furnace in the form of a cupola being thus described, I
shall now proceed to describe the process for producing a melting which once
started may be continued for some time.
A charge of coke is placed upon the grate, and a few pieces in the bottom of
the crucible D. Then the metal to be melted is placed on top of this small
quantity of coke and in the extension which may be filled. The blast is then
turned on, gently at first, and tlien more powerfully, and before any coke com-
mences to sink on the grate successive small charges are fed in.

page_text: unless the desired quantity has been able to be placed at one time for a melt.
Cleaning is effected when necessary through the aperture K, in order to remove
the slag and to leave the whole of the useful space for the melted metal, and
when the fusion is completely effected, the running out hole is unstopped, and
the desired quantity of metal is run out, the procedure being exactly the same
as with an ordinary cupola, for which it may be used as a substitute for melting
small quantities of ore or metal.
The furnace might be erected and charged and operated in the manner above
described, but it is necessary to make provision for the wear and tear of re-
fractory material, and for the necessary repairs. In order to facilitate the con-
struction of the furnace, its erection and the repairs which become necessary
from time to time the apparatus is advantageously divided into four distinct
parts each enclosed in a sheet metal casing of the same diameter fitting in
suitable uniting rings and consisting:
1. Of the part X which encloses the grate and the furnace;
(2) Of the part Y which carries the feeding apparatus;
(3) Of the part Z which carries the crucible;
(4) Of the part W which carries the extension. In each of the casings of these
parts, and all on the same side, there is provided a part m, in which is formed
an orifice M.
Near the furnace, and on the side where it is least inconvenient, there is ar-
ranged a small column N, cast hollow, on the exterior of which there is formed
a longitudinal groove (see Fig. 5).
A screw V, having nuts VVV is operated by means of a hand wheel O,
and three supports S S S are fitted with slight friction upon the said
column. These supports enter at the other end into the notches M, and the
nuts V, V, V which operate them are adjusted in such a manner as regards
their position as to height on the screw V, that on beginning to turn the hand-
wheel O, first the part which contains the extension is raised a few centimetres,
which allows of turning this said first part to the extent desired, on continuing
to turn the hand-wheel, the part which contains the crucible is raised, and then
the part which contains the fuel-feeding device. In this manner each part is
isolated, for the purpose of effecting repairs or for the complete reconstruction
of the furnace.
It will be readily understood that it is sufficient to actuate the column by
means of the central screw in the opposite way, in order to replace all the parts
mentioned in position.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:
1. In a melting furnace of the kind referred to, a fire place arranged at the
lower part of the furnace and adapted to be fed with fuel by means of a lateral
upper feeding device, and having an arch or dome which is formed with aper-
tures through which the flames from the said fire place pass substantially as
described.
2. In a melting furnace of the kind referred to, a crucible made of several
parts of refractory earth, the lower one of which may be of plumbago and which
is provided at the bottom with a hole to which is connected a running-out
passage, and at its upper part with a cleaning aperture, the said crucible bear-
ing by means of ribs against the sides of the furnace and adapted to be enveloped
on all sides by the flames which arise from the fire-place and surround it sub-
stantially as described.
3. In a melting furnace of the kind referred to, an extension made of several
parts of refractory earth, and situated above the crucible in such a way as to
leave between it and the crucible a zone for the circulation of flames from the fire

page_text: place, the said extension being provided at the bottom with a central orifice
for the escape of the material to be melted, or which has been melted, and being
also provided a little above the bottom with lateral apertures through which the
flames which rise up through the peripheral zone surrounding the extension
pass into its interior and by their contact heat the materials to be melted through
which the said flames rise in order to escape through the prolongation of the
extension which serves as the mouth of the furnace substantially as described.
4. A melting furnace such as referred to in the three preceding claims formed
in four distinct separable portions namely:The fixed lower portion consist-
ing of the grate and the fire-place; the portion immediately above, consisting
of the arch, and to which there is attached the fuel-distributing or feeding device,
the third portion counting from the bottom, including the crucible; and finally
the top portion containing the extension, and its prolongation or mouth; the
three upper portions being super-posed on one another, but being each movable
and the furnace thus constructed being combined with an operating column
arranged adjacent thereto, and which enables the raising and turning laterally
to a sufficient extent of each of the three upper portions of the furnace, so as
to allow of inspecting repairing or operating the said portions substantially as
described.
5. An operating column arranged at the side of a furnace consisting of several
movable parts superposed on one another and fitting together as specified in
Claim 4, provided with arms which are raised by lugs that are operated by the
rotation of a stationary endless screw, provided in the centre, and in the axis
of the said column, the arms which rise being journalled at their ends in lugs
fixed to each of the movable portions of the furnace in such a manner that each
part, commencing with the top one, as soon as it is slightly raised, is capable of
being turned to one side, so as to allow the following lower portion to be raised
and turned substantially as described.
6. My improved melting furnace constructed arranged and operating sub-
stantially as described with reference to the accompanying drawings.
Dated this 6th day of December 1898
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.