Improvements in or relating to Furnaces.
Year: 1893

page_text: te of Application, 25th Sept., 1893-Accepted, 28th Oct., 1893
COMPLETE SPECIFICATION.
Improvements in or relating to Furnaces.
1. VICTOR JOSEPH FATTELAY of Le Bernay, near St. Etienne, in the
Department of the Loire, France Steel 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 :—
These improvements relate to the protection of the bars of furnace grates against
the action of the heat generated by furnaces, by covering the said grates with a
layer of refractory materials of greater or less depth.
I am thereby enabled to realise numerous important advantages, among which
notably the following;-
Firstly Great economy in regard to the fire-bars.
The bars of the furnace grate not being exposed to a red heat, can neither rust.
nor buckle, in the absence of such a temperature.
Secondly Economy in the time employed in cleaning.
The refractory materials being arranged in such manner as to retain all dross in
their interstices, the fire-bars are never in contact with the cinder and slag. The
fire-grate being movable by turning it down on its axis the refuse and dross fall.
away from it at once.
Thirdly Great economy in maintenance and repairs.
:
The mass of scoria and refractory materials preserves its heat for a very long
time after the apparatus has ceased active operation, and the cooling process, is,
very slow and prolonged; the fire-bricks and metal fittings escape the dislocation
and deterioration invariably consequent upon sudden changes of temperature.
Fourthly Important economy of fuel.
The layer of refractory materials storing up the scoriæ in the molten state, thesc
latter retain a certain temperature by reason of their small conductivity and large
quantity. The air-supply coming from without and passing through the fire-grate
and the superincumbent heated mass itself becomes superheated when it reaches
the fuel, and naturally therefore increases the activity of combustion and raises the
temperature still more. Further also the rapidity with which such a movable
grate can be cleaned does not allow the apparatus to lose much heat between two
consecutive workings. Lastly the heat lost while the apparatus is in operation
may be utilised in various ways, to heat air, ġenerate steam, or for any other use or
purpose.
Fifthly Economy in respect of crucibles.
The crucibles being raised on hollow stands above the scoriae have the advantage
of being always surrounded by an extremely hot medium and of never becoming
encrusted with dross at their base; whence it follows that the heat acts equally
over the whole of the surface.
The supports of the crucibles being hollow and their interior in communication
through their open base with the external air which tends to cool them the crucibles
are not liable to become adherent to their stands at the points of contact.
The crucibles rest invariably on a fixed plane surface, so there is never any
necessity for readjustment to reset them in an upright and level position.
For the above-named reasons. the crucibles undergo less wear and tear and last
longer making double the number of smeltings as compared with those used in the
ordinary apparatus of like kind heated with coke for processes at present in use.
The firegrates used in my improved apparatus for heating and smelting purposes,
may be horizontal or inclined, fixed or movable and made in one or more sections.
They may be operated by levers, gear-work, racks, screws, jack-screws, or any
other convenient and suitable means; or, again they may simply be drawn out with

page_text: pincers one by one. They may be solid or hollow and of any section in cast or
wrought iron or any other metal.
The layer of refractory substances of all kinds which covers the fire-grate, may
be of any suitable depth more or less in accordance with the nature and form
of the furnace to which my improved process may be applied.
For the purpose of getting rid of cinder and slag any kind of flux may be
used lime sodic carbonate, iron-ore etc. or the refractory mass may be stirred
and broken up to separate the slag and open up fresh passages for the air.
The layer of refractory material may be stirred with an ordinary fire-iron or by
means of a movement communicated to the grate and in either case the action
may take place in any direction, by the aid of levers racks gear etc., set in
operation by any kind of prime motor.
The refractory materials may be either of baked fireclay or not, brickbats
fragments of crucibles and of any form, regular or irregular; such materials may
be of a kind to contract or to dilate under the effects of heat; those which are
the most apt to contract, such as clay, boxite, etc. are preferable; their con-
traction by heat being the more sensitive they ultimately come to occupy the
smaller place, and so offer larger interstitial space for air and scoriæ.
The apparatus to which my invention may be applied may burn combustible
matter of all kinds, coal coke, anthracite, wood gas etc. and supplied with air by
natural or forced draught a chimney blower ventilator or any other machine
creating a current of air by a plenum or vacuum.
The heating apparatus may be fixed or portable, and the objects to be heated
may or may not come in contact with the fuel.
To facilitate comprehension of my improved system, the accompanying drawings
exemplify its application to a crucible-steel furnace, for melting steel or any
other metals, which will be readily understood by the following explanation and
references ;-
Throughout, the same letters indicate the same parts;
a. Debris and fragments of refractory material on the grate;
b. Movable fire-grate ;
c. Hollow stands, supporting the crucibles;
d. Crucibles;
f. Chimney outlet ;
7. Airhole and damper.
According to the general arrangement shown in the drawings, the fire-grate
having been properly adjusted in its fittings, the hollow crucible-stands are
arranged directly thereon, and the charge or layer of refractory materials is
evenly distributed around them to the desired depth. The fire is then lit, and
when the furnace is sufficiently heated the crucibles are placed on their stands
and duly charged with the metal to be melted.
When the melting operation is completed the slag is broken up, from the opening
at the top of the furnace, by a few strokes of the fire-iron.
Whenever the refractory layer becomes surcharged with slag, which may happen
after about 24 hours working, the movable rest of the fire-grate is withdrawn,
allowing the grate to drop and with it the refractory layer and the crucible-stands.
The grate is then replaced in position, with other stands and refractory layer as
before, these being kept ready for immediate use, in order to avoid loss of time and
cooling of the furnace.
During working the temperature of the stove may be increased or lowered as
desired, by the damper.
The entire furnace may be enclosed in metal either wholly or only in part.
Having now particularly described and ascertained the nature of the said
invention and in what manner it is to be performed, I declare that what I
claim is ;-
1. A refractory layer placed upon the furnace grate to protect it from the

page_text: excessive heat of the furnace and rapid changes of temperature and thus prevent
its rapid destruction.
2. The construction and arrangement of a furnace grate which enable the
cleansing operation to be rapidly effected substantially as and for the purpose
described and illustrated in the accompanying drawings.
3. The combination and arrangement of parts constituting the complete furnace
substantially as described and illustrated in the accompanying drawings.
Dated this 25th day of September 1893.
W. P. THOMPSON & BOULT,
Of London, Liverpool, Nottingham, and Manchester,
Agents for the Applicant.