CERTAIN IMPROVEMENTS IN CASTING CYLINDERS, TUBES, AND OTHER ARTICLES OF IRON, COPPER, AND OTHER METALS
Year: 1825

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CHURCH, of Birmingham, in the County of Warwick, Esquire, send greeting.
WHEREAS His present most Excellent Majesty King George the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Eighteenth day of January, in the fifth year of His
reign, did; for Himself, His heirs and successors, give and grant unto me, the
said William Church, His especial licence, that I, the said William Church,
iny exors, adiiors, or assigns, or such others as I, the said William Church,
my exors, adñiors, and assigns, should at any time agree with, and no others,
from time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick upon-Tweed, and also in His said Majesty's
Colonies and Plantations abroad, my Invention of "CERTAIN IMPROVEMENTS
IN CASTING CYLINDERS, TUBES, AND OTHER ARTICLES OF IRON, COPPER, AND OTHER
METALS;" in which said Letters Patent there is contained a proviso obliging
me, the said William Church, by an instrument in writing under my hand
and seal, particularly to describe and ascertain the nature of my said Inven-
tion, and in what manner the same is to be performed, and to cause the
same to be inrolled in Iis Majesty's High Court of Chancery within six
calendar months next and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereunto
hal, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
William Church, have herein particularly described the said Invention, and
in what manner the same is to be performed as follows, that is to say -
My Invention of Certain Improvements in Casting Cylinders and other
Articles of Iron, Copper, and other Metals, is designed to render such castings
more perfect, sound, and free from air holes, and at the same time more com-
pact and uniform in texture than such castings have heretofore been, and in
which process
I am enabled to effect a more uniform case-harden'd surface
when required. For this purpose I employ both exhaustion and condensation
of air in my process, and therefore combine such apparatus as will enable me
to effect those objects in a convenient way. But as the great variety of articles
to be cast must necessarily require differently-formed apparatus, and as I
cannot possibly describe every form that circumstances may render eligible, I
have mearly exhibited in the Drawing which accompanies this my Specifica-
tion one construction of apparatus (by way of ellucidation) which I should
employ for casting cylinders or rollers. The Drawing represents a section of the
mould and its appendages suspended by means of chains to an ordinary crauc,
and also a section of the pan or metal chest, with an air pump and an air
vessel connected both to the mould and to the metal chest by means of tubes
with union joints. The mould in this instance consists of a hollow cylinder of
iron a, a, a, a, with flanges at the ends, the interior being bored or otherwise
truly formed to the figure of the intended cylinder or roller about to be cast.
b, b, is an outer case or jacket surrounding the mould, and leaving a space
between for the passage of cold water, which I purpose to conduct through this
passage at the time of casting by means of a pipe leading from a cistern or other-
wise, and a cock at bottom in order to cool the mould; c, c, and d, d, are caps
to be attached to the ends of the mould in which I form the hollows or recesses
for casting the gudgeons and ends of the rollers. These caps and the jacket
are all united to the cylindrical mould by means of screw bolts passing through
the flanges. In the upper part of the cap C a small channel is made with a
conical valve, and a short piece of pipe is attatched at the mouth of the
orifice with a stopcock, through which channel and pipe the mould is to be
exhausted. At the lower end of the cap d a pipe or tube / is attached by a
gland, and rendered air tight, which pipe is made of such material as will
resist the action of heat, or such as crucibles are usually composed of. Through
this pipe the melted metal is intended to flow into the mould. The lower end
of this tube is covered by a cap of iron or other metal, which should be made
to fit the tube closely, and be luted at the upper edge. The mould thus put
together is to be suspended by chains from the crane, and then the pipe g,

page_text: which is attached by a cock-joint to the air pump h, is to be connected to the
short pipe e by means of the union joint. The joints of the mould being now
properly luted and rendered air tight, the air pump is put to work, and the
interior of the mould exhausted, in which state it is ready for casting, or it
may have been previously exhausted by the ordinary application of an air
pump. The pan or metal chest may be ofany convenient form; that shewn in
the Drawing at i, i, is prefered, and it must be of such capacity as will
contain a sufficient quantity of melted metal to produce the article about to be
cast. This pan is to be inserted in another pan or vessel k, k, and the space
between the two to be filled with pulverized charcoal, or other materials that
are imperfect conductors of heat. The pan with the melted metal is to be
brought from the furnace, and placed in such a situation under the mould
that the mould may be lowered down to it, and the pipe f immersed in the
melted metal, the conical form of the flange at the bottom of the cap d fitting
into the rim 1, 1, on the top of the metal chest; and in order to make the joint
more close a springing hoop m, of wrought iron and of a wedge form, is placed
round within the rim in contact and, forming an air-tight joint with the
upper edge of the rim, which giving way at bottom, the pressure of the
mould forms an air-tight joint. Through the lower flange of the cap d there
is a small aperture with a short piece of pipen attached to it. Through this
aperture and pipe the air may be drawn from or forced into the metal chest i,
the mould and metal chest being now united, as shewn in the Drawing. The
pipe O, which is attached the air pump and to an exhausted air vessel p by
means of a three-way cock joint q, is connected to the short pipe » by an union
joint, and the whole of the apparatus is now ready for effecting the casting.
In commencing the operation the cock 9 is to be turned so as to open the
communication between the metal chest i and the exhausted air vessel p, by
which the pressure of the atmosphere is removed from the surface of
the metal for the purpose of preventing it from rushing up the pipe into
the exhausted mould when the mouth of the pipe opens by the melting of the
metal cap, which cap is to be made of such metal and thickness as will allow
it to melt shortly after the immersion of the pipe in the fluid metal. The
cock 9 is now to be turned so as to cut off the communication from the
exhausted vessel p, and open a communication with the lower end of the air
pump. It is here to be observed that the air pump is employed both as an
exhaustion and forcing pump, and its piston being now put in action, air s
forced from the lower end of the pump through the pipe O into the metal
chest, which forces the metal up the pipe, and thereby causes it to fill the
mould. To guard against the presence of any air which might have gained

page_text: ]
access to the interior of the mould, I open the stop cock e, which leads through
the pipe to the exhausting end of the pump, and as the pump forces air onto
the surface of the melted metal a constant vacuum is keep up in the interior
of the mould above the rising metal. In order to prevent the metal flowing
thro' the exhausting passage, I suspend in the cap ca conical float valve,
which, as the metal rises, closes the aperture. It may be necessary to
remark, that I have not shewn the valves of the air pump, as that apparatus is
already understood. It is obvious that moulds which are designed to cast
articles having irregular surfaces, such for instance as cannon, that cannot be
slidden out, must be constructed of parts put together soas to render them air
tight. Tho' I have shown in the Drawing a jacket surrounding the cylindrical
part of my mould for the purpose of conducting cold water, yet I do not
intend, under all circumstances, to employ that mode but only when I desire to
give the casting a case-hardened surface.
Having thus explained the manner in which I effect my improvements in
casting, and which process will admit of some variation, I wish it to be under-
stood that my particular claim of novelty consists in the combination of
apparatus by which I am enabled to exhaust the mould & to preserve it in an
exhausted state; and also to allow the melted metal to flow gently into the
mould, and by which apparatus I am likewise enabled to give any desired
pressure to the melted metal while in a fluid state, and thereby produce a more
perfect casting.
In witness whereof, 1, the said William Church, have hereunto set my
hand and seal, this Sixteenth day of July in the yearof our Lord 1825