IMPROVEMENTS IN CRUCIBLES AND OTHER VESSELS FOR MELTING, REFINING OR CONVERTING METAL AND MEANS FOR HEATING
Year: 1884

page_text: PROVISIONAL
DEECIFICATION,
I JOHN GUY WILSON of the British & Foreign Patent Office, 71 Market Street,
Manchester in the County of Lancaster, Mechanical Engineer do hereby declare
the nature of the said invention for "IMPROVEMENTS IN CRUCIBLES AND OTHER
VESSELS FOR MELTING, REFINING OR CONVERTING METAL AND MEANS FOR HEATING
"
THE SAME a communication from abroad by Joseph Elton Bott of Linwood,
Delaware County State of Pennsylvania, United States of America, to be as
follows:-
My invention consists in so constructing and heating a crucible or other vessel
that large masses or quantities of metal can be melted, refined or converted therein
and poured therefrom directly into moulds for forming ingots or castings without
the use of ladles and without tilting the said vessel whereby as applied to steel
castings the use of a large number of small crucibles (necessary to make a large
casting) is entirely dispensed with and the entire quantity of metal is melted in
one crucible, the result being as a matter of course a perfect admixture of tho
various materials a great saving in time, labour and in the number of workmen
employed and the resulting casting is free from the many risks now attending the
production of crucible-steel-castings from a number of small crucibles each requiring
separate handling with its attendant disadvantages.
Furthermore in accordance with this invention and by the flow of the molten
metal directly into castings or ingots without the medium of ladles the metal is
perfectly protected from sculling and from loss of heat-oxidization from the
atmosphere is in a great measure prevented; absolutely no skimming is required
and the direct flow of the metal as aforesaid at an almost equal temperature is
conducive to the production of more perfect and homogeneous castings or ingots
than has hitherto been practible.

page_text: The improved crucible consists of an outer casing of plate iron or other suitable
material having an inner lining of firebrick or other refractory substance the
crucible being preferably of a rectangular form whero a regenirative gas furnace
supplies the necessary beat and of a circular or oval form where gas is used direct
from a producer or other source of supply.
At each end of the crucible are two vertical refractory partitions or walls forming
flue spaces whilst in the centre of the crucible is a central flue also enclosed by a
refractory circular wall; the internal space between the sides of the crucible and
the end partitions and surrounding the said central enclosed fiue forms the melting
chamber whilst tapping holes are made in the bed for the purpose of running off
the molten metal. The crucible is covered with a removeablo reverberatory domo,
for the purpose of charging the molting chamber with the metals or other inaterials
to be melted or otherwise treated and auxiliary charging doors are constructed in
the said dome or the sides of the crucible for the purpose of making additions to
the molten metal or stirring the same.
Tapping holes are also made in the side of the crucible on a level with the bed,
in order that samples of the molten metal may be obtained from time to time.
Where a regenerative gas furnace supplies the necessary heat for melting I form
the regenerators of a series of vertical baffle plates or boxes of a corrugated or wavy
configuration so that all dust and other accumulations fall to the bottom of the
regenerators into a collecting chamber thus increasing the durability of the regenc-
rators and avoiding the necessity of pulling down the wall for cleansing purposes.
The crucible is carried on a truck having wheels running on a suitable track
over flues corresponding with the end and central flues of the crucible through
which flues the gas and hot air are supplied in order that the combined gas and
hot air from one pair of regenerators may pass over and around the metal or other
material in the cruciblo undergoing treatment and then pass into the other pair of
regenerators the currents of gas and air being controlled and reversed from time to
time by means of the ordinary two way valve arrangement fitted to the gas and
air supply pipes respectively.
When the gas is supplied direct from a generator or producer without the inter-
vention of regenerators I prefer to make the crucible of circular or oval shape and
admit the necessary supply of air into a combustion chamber having corresponding
inlet and outlet ports with the crucibles surmounting same and I admit gas and air
into the said combustion chamber in the form of compound annular jets cach
circumference being by preference waved or irregular in contour-the central jet
consists of air and is surrounded with an annulus of air whilst the whole is
surrounded with another annulus of gas forming the outer envelope this form of
jet insuring the perfect mixture of gas and air necessary to ensure a high heat being
obtained.
•
The air being supplied by pipes passing through the hot gas and also becoming
heated.
In cases where it is impracticable to use gas for heating the crucible and it is
necessary to use coke, I prefer to construct the crucible with ports as before and to
fill the said ports with coke or other combustible communicating with a furnace
under same and having the necessary tuyeres for the admission of air.
Where the crucible is of large dimensions I prefer to support the same on a truck
having wheels capable of being moved on a suitable track over an ingot-pit or over
large moulds for castings the truck and crucible being moved by steam, hydraulic,
or other mechanical contrivance. But 1 do not confine myself to this method of
handling or moving the crucible as in the case of Binall crucibles having to be
carried or conveyed in various directions, I would prefer to construct the crucible
with suitable rings or shackles by which they could be transported as required by
a crane or its equivalent.
When the process of melting has continued for a sufficient length of time and the
sample of molten metal taken from the side tapping holes have prooved satisfactory

page_text: the flow of gas and air is stopped and the crucible is wheeled off or otherwise
conveyed to the casting floor, or ingot-pit when the molten metal is run out of tho
tapping holes in the bottom of the bad refractory plugs operated by levers or other
suitable mechanical equivalents controlling the flow of the molten metal from the
crucibles such refractory plugs being secured at the extremity of metal tubos
protected on the outside by being surrounded by strips of asbestos cloth wound on
in a spiral direction and the intervening spaces being well filled in and the outside
painted over with two or threo coats of asbestos print.
JOHN G. WILSON,
Agent for Applicant.
COMPLETE SPECIFICATION.
I JOHN GUY WILSON, of the British and Foreign Patent Office, 71 Market
Street Manchester Lancashire Mechanical Engineer do hereby declaro the nature of
the Invention for "IMPROVEMENTS IN CRUCIBLES AND OTHER VESSELS FOR MELTING
REFINING OR CONVERTING METALS, AND MEANS FOR HEATING THE SAME," A com-
munication to me from abroad by Joseph Elton Bott of Linwood, Delaware,
Pennsylvania in the United States and in what manner the same is to bo
performed, to be particularly described and ascertained in and by the following
statement:-
This invention consists in so constructing and heating a crucible furnace or other
vessel that large masses or quantities of metal can be melted, refined, or converted
therein, and poured therefrom directly into moulds for forming ingots, or castings,
without the use of ladles and without tilting the said vessel; whereby as applied
to steel castings the use of a large number of small crucibles (necessary to make
large castings) is entirely dispensed with, and the entire quantity of metal is melted
in one crucible furnace, the result being as a matter of course a perfect admixture
of the various materials, a great saving in tine, labour, and in the number of
workmen employed, and the resulting castings are free from the many risks now
attending the production of crucible steel castings from a number of small crucibles
each requiring separate handling with its attendant disadvantages; Furthermore
in accordance with this invention and by the flow of the molten metal directly
into castings or ingots without the mediums of ladles the metal is perfectly
protected from sculling and from loss of heat-oxidization from the atmosphere is
in a great measure prevented; absolutely no skimming is required and the direct
flow of the metal as aforesaid at an almost equal temperature is conducive to the
production of more perfect and homogeneous castings or ingots than as hitherto
been practicable. The improved crucible furnace consists of an outer casing of
plate iron or other suitable material having an inner lining of fire-brick or other
refractory substance, the crucible furnace being preferably of a rectangular form
where a regenerative gas furnace supplies tho necessary heat, and of a circular or
oval form where gas is used direct from a producer or source of supply:
At each end of the crucible furnaces are two vertical refractory partitions or
walls forming flue spaces whilst in the centre of the crucible furnace is a central

page_text: flue also enclosed by a refractory circular wall; the internal space between the
sides of the cruciblo furnace and surrounding the said central enclosed flue forms
the melting chamber, whilst tapping holes are made in the bed for the purpose of
running off the molten metals. The crucible furnace is covered with a removeable
reverberatory dome or cover for the purpose of charging the metal chamber with
the metals or other materials to be melted or otherwise treated and auxiliary
charging doors are constructed in the said dome cover, or the sides of the crucible
furnace, for the purpose of making additions to the molten metal or stirring the
same.
Tapping holes may also be made in the side of the crucible furnaco on a level
with the bed in order that samples of the molten metal may be obtained from time
to time.
The crucible is carried on a truck having wheels running on a suitablo track over
flues corresponding with the end and central flues of the crucible through which
Hlues the gus and hot air are supplied, in order that the combined gas and hot air
from one pair of regenerators may pass over and around the metal or other material
in the crucible undergoing treatment, and then pass into the other pair of regene-
rators, the currents of gas and air being controlled and reversed from time to time
by means of the ordinary two way valves arrangement fitted to the gas and air
supply pipes respectively. When the cruciblo is of large dimensions 1 prefer to
support the same on a truck having wheels, capable of being moved on a suitable
track over an ingot pit or over large moulds for castings-the truck and crucible
being moved by steam, hydraulic or other mechanical contrivance. But I do not
confine myself to this method of handling or moving the crucibles having to be
carried or conveyed in various directions; I would prefer to construct the crucible
with suitable rings or shackles by which they could be transported as required by
a crane or its equivalent:-or in the case of large ingot furnaces I prefer to make a
passage between the regenerators and convey portable or other moulds underneath
the tupping holes through which the molten metal can be poured direct. When
the process of melting has continued for a sufficient length of time and the samples
of molten metal taken from the side tapping holes have proved satisfactory, the
How of gas and air is stopped and the crucible is wheeled off or otherwise conveyed
to the casting floor or ingot pit, when the molten mictal is run out of the tapping
holes in the bottom of the bed ;-refractory plugs, operated by levers or other
suitable mechanical equivalents controlling the flow of the molten metals from the
crucibles, such refractory plugs being secured at the extremity of metal tubes
protected on the outside by being surrounded by strips of asbestos cloth wound on
in a spiral direction and the intervening spaces being well fitted in and the outside
painted over with two or three coats of asbestos paint or cement.
On the accompanying drawing Fig 1 is a longitudinal elevation and Fig 2. an
end elevation (both partly in section) of my improved crucible furnace.
Fig 3 is a longitudinal elevation showing the portable bogie and track on the
fixed part of the furnace.
Fig 4 is a plan view of the refractory tapping plug and Fig. 5 is an elevation of
part of the same.
Fig. 6 is a sectional plan and Fig 7 a vertical section of the same tapping plug.
Similar letters refer to similar parts in all the views.
This improved crucible furnace consists of an outer casing of plate iron A having
a refractory lining B, a melting chamber B a sole plate C on which a base of
refractory material C and tapping blocks D are laid. On these latter, the
crucible E or crucibles proper rest; The melting chamber B' communicates with
a regenerative combustion chamber F by means of ports G G-the said combustion
chamber F receiving air by the ports H H and gas by the ports II alternately.
This air and gas thus meet in the combustion chamber E, there unite together and
form the usual intense heat which by natural laws rises and fills the crucible
furnace through the ports G G with an even supply of gas in a stato of almost
perfect combustion-and which by surrounding and radiating on the crucible E or

page_text: crucibles thereby causes the metal contained in the same to be rapidly melted and
afterwards kept at a constant temperature.
The crucible E so heated is constructed as illustrated with a tapping hole J at
the bottom communicating with a similar hole through the tapping blocks D and
controlled by a tapping plug K (hereinafter more particularly described) the stem
of which passes through the removable reverberatory covers L L.
The shell or casing A has attached to it, carrying brackets M M which rest on a
bogie frame N, supported on wheels O O travelling on the track P P.
The crucible furnace may be used either as a fixed superstructure on the com-
bustion chamber F-in which case the molten metal from the crucible E may bo
run by means of a heated conduit direct from the tapping holes J and D into
ingot inoulds placed near the furnace or the crucible furnace may be mounted on
and supported by the bogie N and thus be traversed over the inget or other mould
to be poured-suitable power being applied for that purpose.
In either case the crucible E containing the molten inetal is not removed from
the melting chamber B₁ but the metal can be tapped direct from the bottom of the
crucible without skimming and still be free from slag &c.-all manipulation being
done from the outside by means of the tapping plug K-thus considerably
increasing the life of crucibles and allowing the use of those of great capacity,
actual handling of the same being dispensed with.
In order that the tapping plug K may not become melted during fusion of
the metal, the same is constructed of a hollow iron tube and of a cruciform section
internally as seen in Figs 6 and 7 and is spirally wrapped with asbestos strips R
after previously painting the iron with. asbestos cement the wrapping R is secured
at the top by a ring S and at its lower end is attached a refractory valve T secured
to the plug K by means of pins U.
The object of making the plug K hollow is to permit a current of air to pass
through the cruciform centre and so keep the metal of the tubo or stem K below
melting point the circumference exposed to the molten metal being protected from
actual contact by means of the asbestos wrapping K.
A solid crucible of large dimensions may be used successfully inside the melting
chamber B but I prefer to use largo crucibles E of the ordinary shape, having
tapping holes at their baso as described-such being much more easily repaired or
renewed.
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 as the improvements in crucibles and other vessels for melting refining or
converting metals and means for heating the same is
1st The improved construction and arrangement of crucible furnace having a
melting chamber in which are a crucible or crucibles having tapping holes at the
bottom, heated and operating substantially as and for the purposes hereinbefore
described and illustrated on the accompanying drawing.
2nd The improved construction and uso of tapping plugs with hollow stem and
externally covered with asbestos to prevent fusion substantially as and for the
purpose heroinbefore described and illustrated on the accompanying drawing.
Dated this 23rd day of January 1885.