IMPROVEMENTS IN DISCHARGING OR TAPPING MOLTEN METAL FROM FURNACES OR CRUCIBLES, AND IN CASTING THE SAME INTO MOULDS
Year: 1872

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN DISCHARGING OR TAPPING MOLTEN METAL FROM
FURNACES OR CRUCIBLES, AND IN CASTING THE SAME INTO MOULDS."-A
communication from abroad by William Sellers, of the City and
County of Philadelphia, in the State of Pennsylvania, United States
of America.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 10th January 1872.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
5 of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN DISCHARGING OR TAPPING MOLTEN METAL.
FROM FURNACES OR CRUCIBLES, AND IN CASTING THE SAME INTO MOULDS," a com-
munication to him from abroad by William Sellers, of the City and County

page_text: of Inuladelpшa, in the state of rennsylvania, United States of America,
to be as follows:-
This Invention relates to a novel method of discharging the molten
metal from the furnace or crucible in which it has been melted, and of
casting or transferring the same into moulds or into another furnace or
crucible without piercing any part of the hearth or bed of the furnace
or removing the crucible from the furnace in which it has been heated,
and without exposing the molten metal during its transit to the action of
the air, thereby avoiding the oxydizing effect of the air thereon and pre-
venting the conveyance of air along with the metal-into the moulds.
In carrying out this Invention the transfer of of the metal is effected
through a pipe or conduit by the agency of atmospheric pressure, onc
end of the said pipe or conduit dipping down below the surface of the
molten metal in the furnace or crucible, whilst the other end is in direct
communication with the mould, so that on exhausting or partially ex-
hausting the air from the interior of the mould or group of moulds the
molten metal will flow freely therein being forced along the pipe or
conduit by the pressure of the atmosphere upon the surface of the metal
in the furnace or crucible. The moulds are completely covered or closed
in, and are in communication by means of pipes and stop-cocks with an
exhausted vessel or chamber, or with any apparatus capable of producing
a rapid exhaustion of the air contained within the pipes and moulds.
This exhaustion takes place at the moment the metal is to be run into
the said moulds by opening a stop-cock or cocks. When the flow of
metals into the moulds is to be arrested air is allowed to enter the
discharging pipe or conduit by a stop for that purpose fitted thereon,
whereupon the whole or a portion of the molten metal in the pipe
returns again to the furnace or crucible whilst the remainder, if any,
flows into the mould.
In some cases,
in lieu of an air cock on the discharging pipe or
conduit, a slide or sluice may be employed having an air passage
made in it so that when shut down so as to close the pipe and arrest
the reflux of metal from the mould it will at the same time vent
that portion of the pipe or conduit which leads down direct to the
furnace or crucible, thereby ensuring the return of the metal thereto;
the said mould is situate at a higher level than the furnace or crucible,
and the stream of molten metal is caused to flow upwards by atmos-

page_text: pheric pressure through the side of the flask into the lowest part of the
mould.
The connection of the discharge pipe with the mould may be effected
in various ways; for ingot moulds it is preferred to make the joint a
partial spherical surface and to pack round the exterior of the same with
sand so as to exclude air.
In transferring molten metal from the furnace or crucible in which it
is melted to a second furnace or crucible for subsequent treatment a
cover must be fitted to the end of the pipe or conduit in the second
furnace or crucible, which in this instance should be placed at a lower
level than the first one, and communication with the exhausted receiver
or exhausting apparatus is established through the said cover in the end
of the transfer pipe or at any other point below the end in the melting
furnace or crucible.
› SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 4th July 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Mid-
dlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of January, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special license
that I, the said John Henry Johnson, my executors, administrators,
and assigns, or such others as I, the said John Henry Johnson, my
executors, administrators, or assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "Im-
PROVEMENTS IN DISCHARGING OR TAPPING MOLTEN METAL FROM FURNACES OR

page_text: CRUCIBLES, AND IN CASTING THE SAME INTO MOULDS," a communication to me
from abroad by William Sellers, of the City and County of Philidelphia,
in the State of Pennsylvania, United States of America, upon the
condition (amongst others) that I, the said John Henry Johnson, my
executors or administrators, by an instrument in writing under my hand 5
and seal, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
1
Letters Patent.
NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the accom-
panying Drawings, and to the letters and figures marked thereon, that
is to say :-
The said Invention comprises a novel method of drawing off or dis-
charging the molten metal from the furnace or crucible in which it has
been melted without piercing any part of the hearth or bed of the
furnace, or removing the crucible from the furnace in which it has been
heated.
Also a novel method of transferring molten metal from furnaces or
crucibles to moulds, or from one furnace or crucible to another without
the intervention of any ladle or other similar apparatus.
Also a novel method of transferring molten metal from furnaces or
crucible to moulds, or from one furnace to another without exposing it to
the air in passing from the one to the other so that it shall have no
opportunity to become oxydized by such exposure, no opportunity to
carry air with it into the moulds or second furnace, and less opportunity
to part with its heat than in any of the methods herein-before practised.
Also a novel method of arresting the discharge of molten metal from
furnaces or crucibles after said discharge has been established, and of re-
establishing said discharge after it has been arrested without the use of
tapping irons or clay stoppers, or without moving the crucible should the
molten meltal be contained in such a vessel.
Also a novel method of preventing waste of molten metal in dis-
charging it from a furnace or crucible into a secondary furnace or

page_text: metal when CARBOT be uenyered when the discharge ISI DO
the furnace or crucible from which it was discharged.
Also a novel method of delivering the metal into the moulds and
retaining it therein after the cast has been made.
Also a novel method of venting the moulds so that the metal shall not
be exposed to the air whilst the cast is being made.
A vertical section of the peculiar discharging or tapping apparatus
with a portion of a furnace in connection therewith is represented in
Figure 1 of the accompanying Drawings which form part of this
Specification. A is the bed or hearth of the furnace, the lines indicating
the depth of the molten metal thercon. The door for charging the metal
into the furnace is not shown; a door B smaller than the one used for
charging is placed convenient to the deepest part of the hearth for the
purpose of examining the condition of the metal, and also for the
purpose herein-after described; c, c, c, are ingot moulds (shown also in
plan in Figure 2) arranged upon a single bed plate D, and connected
with each other by semicircular gates in the bed plate as now and here-
tofore practiced. This bed plate is mounted upon wheels which rest
upon rail tracts so as to be conveniently run into and out of an oven in
which the moulds may be heated previously to making a cast. The top
of each of these moulds is faced off, and is provided with a cover also
faced off so as to fit with reasonable accuracy. The cover of the central
mould is much higher than the others, in fact in this instance it is a
pipe having a bowl-shaped top E. The inside of this bowl is cylindrical
with a spherically formed bottom, and in the centre of this is an opening
leading to the interior of the central mould. This central cover or pipe
is secured to the top of the central ingot mould by the hook bolts d, d,
Figure 3. From the bowl E to the interior of the furnace a bent cast-
iron pipe F extends, having one end fitted to the bottom of the bowl E,
and the other end enlarged to receive the tube G which may extend to
the hearth of the furnace when the pipe F rests upon the sill of the
door B. The tube G may be composed of the material used for crucibles
in steel furnaces, and is luted into the end of the pipe F with daubing
similar to that used for repairing crucibles, and the portion of the pipe F
within the furnace is covered with the same material to protect it from
the heat of the furnace.

page_text: Outside the door B the pipe F is slung so as to be raised and lowered,
the details of the suspension being shown in Figure 4, in which a band
carrying four wheels is exhibited, and upon the lower wheels the pipe is
supported so as to turn freely about its axis, the upper wheels serving
only to retain the wheels and band in position upon the pipe by the
collars e, e, cast with the pipe. To the bent end of the pipe F outside
the furnace I attach a handle H for the purpose of guiding it when
placing it in position; this handic can be readily removed when the pipe
is not in use or when it is placed in a furnace to dry the daubing before
E
fan making a nost

page_text: object of this float being to determine when a sufficient quantity of
metal has been run into the moulds.
The apparatus being in position, and the metal at the proper tempera-
ture, the cock n may be opened, when the pressure of the atmosphere
upon the molten metal in the furnace will cause this metal to be dis-
charged into the moulds, and when a sufficient quantity has entered as
will be shown by the float o, the cock should be opened, admitting air to
the interior of the pipe F; the metal in this pipe will then be partly
discharged into the moulds, and partly returned into the furnace, leaving
a thin film of metal only around the interior of the pipe; as soon as
this takes place the cock m should be closed.
To re-establish the discharge the cock n should be closed, and the
cock m in the pipe communicating with the exhausted closed vessel
before mentioned opened, thus relieving the interior of the pipe F from
atmospheric pressure, when the molten metal will immediately commence
to flow through it as before.
A modification of the central cover and the discharging end of the
pipe F, is shown at Figures 5 and 6. In this case the cover has a socket-
shaped tap to receive the spherically formed end of the pipe F, to which
it is attached by links p, p, so that the pipe can vibrate freely in the
socket, in the cover a ring r, r, surrounds the top of the mould and rests
upon it, this ring being of sufficient height above the mould to retain the
sand packing above the socket in the cover, and also sufficiently larger
than the cover to permit the sand to close the joint between the cover
and the top of the mould, in other particulars it is similar to the pipe F
first described.
This modification is more simple and more easily adjusted than the
one first described and is equally efficacious, but when the taps of the
moulds are far below the furnace it is not so convenient owing to the
length of the vertical part of the pipe F required to reach the moulds.
Figures 7, 8, 9, and 10 represent a modification of the arrangement
for casting from a crucible into sand moulds. The flasks are of iron and
of the ordinary construction with the exception of the lug S which is
cast upon the side of one of the flasks near to one corner. This lug is
cast with a rectangular opening through it, and this opening is dressed
out to receive the plug or slide v and allow to play freely therein.

page_text: This slide has a small hole extending downward from the top a certain
distance until it meets with another similar hole extending inward from
the outer surface of the slide, the use of which will be herein-after men-
tioned. It is also provided at its upper end with an outward projecting
lug to limit the downward motion of the slide. The pipe F leading
from the mould to the crucible is in this instance wrought iron, and bent
to a convenient form, and is provided at the end next the flask with a
collar spherically formed upon its outer side, by means of which the
pipe is secured to a socket conformably shaped in the lug S.
When the mould is rammed a pattern plug is inserted through holes
x, x, in the lug S and the side of the flask, the rectangular opening in
the lug S is rammed with sand the same as the interior of the flask and
the plug is withdrawn, when the mould is completed and the patterns
removed, and the opening left by the plug is made to communicate with
the openings from which the patterns have been removed in the usual
manner.
The pipe k, Figure 7, leads to the exhausted closed vessel before
mentioned, and is provided with a cock n as in the apparatus before
described. Its interior is in communication with the mould left by the
pattern through ducts formed in the sand as ordinarily practised for the
rising gate, and the slide is placed in position as shown in Figures 6
and 7. To prevent the air from drawing through the sand I cover the
top and bottom of the mould with a thin sheet of india-rubber or vul-
canized gum, over which the usual wooden coverings are placed and
secured by clamp screws, as ordinarily practised. The openings or joints
between the flasks are luted with stiff clay.
The mould is now placed with reference to the crucible and molten
metal as shewn in Figure 7, the pipe F is heated to prevent chilling the
metal, and immediately secured to the flask, the cock n is opened, and
the metal is forced from the crucible into the mould by the pressure of
the atmosphere upon the surface of that in the crucible. As soon as the
mould is filled the slide v is driven downward as far as the lug upon its
upper end will permit, forcing out the sand below it in the lug S and
preventing the return of the metal in the flasks. At the same time the
hole in the slide will be brought into the position shown in Figure 9,
which will allow the air to enter the upper end of the pipe F and permit
the metal contained therein to flow back into the crucible.

page_text: In transferring molten metal from the furnace or crucible in which it
is melted to a second furnace or crucible for subsequent treatment, the
cover which is used for the central mould must be applied to the end of
the pipe F in the second furnace or crucible, which in this instance
must be placed lower than the first; communication with the exhausted
receiver or exhausting apparatus may be made through the aforesaid
cover or into the pipe F at a point below its end in the melting furnace
or crucible. After the air has been exhausted from the pipe F as hercin-
before described, and this pipe is filled with molten metal, the cover
must be removed and the discharge will continue until the molten
metal is exhausted or until its flow is arrested as herein-before
described.
To re-establish the discharge after it has been arrested in the manner
described, or from any accidental accumulation of air or gas in the
pipe F, the cover must be replaced on the end of the pipe and the air
exhausted as before.
The method of casting herein-before described is especially applicable
to alloys of zinc, copper, iron and tin, which rapidly oxydize by being
exposed to the air in a molten state, and in consequence thereof the
castings are liable to blow holes which the process described will
obviate.
The details required for convenient working must be arranged to suit
the various locations of the apparatus in which the process is to be
employed, and the materials with which it is intended to operate. I have
stated herein that a vacuum of twenty-two inches will give a good result
generally, but it is evident that the amount of vacuum required will
depend upon the specific gravity of the molten metal and the height to
which it must be lifted.
It might be supposed that the rapid expansion of the air contained
between the particles of sand in a sand mould would destroy the mould
when suddenly connected with an exhausted receiver, but the mould is
not affected by such connection when made as suddenly as a cock can be
turned, and the metal flows into it without the disturbance which
frequently occurs when poured from above as usually practised in this
class of work.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or

page_text: carried into effect, I would observe in conclusion that I am aware that it
has been proposed to raise the molten metal into moulds in which a
partial vacuum has been formed, and that pipes or conduits have been
proposed for transferring molten metal from a convenient receptacle to
an exhausted mould, and that it has been proposed to run molten metal i
from one furnace to another through suitable channels by gravitation,
and therefore I lay no claim thereto as forming any part of the present
Invention, but what I consider to be novel and original, and therefore
claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,―
First. The door B or its equivalent for discharging or drawing off the
molten metal from a furnace or crucible situate at a point above the
surface of the metal on the hearth or in the crucible, substantially as
described.
1
Second. The combination of a furnace or crucible in which the metal is 1
melted, a mould in which the metal is cast, and a conduit through which
the metal is transferred directly from the furnace or crucible to the
mould in the manner herein-before described.
Third. The combination of a furnace or crucible in which the metal is
melted, a secondary furnace or crucible in which the metal is treated, 2
and a conduit through which the metal is transferred directly from the
onc furnace or crucible to the other, substantially as described.
Fourth. The combination of the melting furnace, the pipe F through
which the metal flows, a secondary furnace, and the pipe k through
which the air is exhausted from the pipe F, substantially as and for the 2
purposes described.
Fifth. The combination with the mould of the pipe F through which
the metal flows from the furnace or crucible in which it has been melted
to the mould, and the pipe through which the air is exhausted from
the mould, substantially as and for the purposes described.
Sixth. The combination with the conduit F, and the air exhaust % of
the air cock m or its equivalent, substantially as described.
3
Seventh. The combination of the melting furnace, a secondary furnace
or a mould, a pipe F or its equivalent, and a cut off air cock m or its
equivalent, substantially as described, whereby when the discharge of the 3

page_text: metal is arrested all that cannot be delivered to the secondary furnace or
mould will be returned back to the melting furnace.
Eighth. The combination with the mould of a gate, substantially as
and for the purposes described.
Ninth. The combination with the mould and the reflux gate of an air
valve, substantially as and for the purposes described.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, the Third day of July
One thousand eight hundred and seventy-two.
J. HENRY JOHNSON. (L.S.)