A NEW AND IMPROVED MODE OF MAKING AND VENTING CORES AND PARTS OF MOULDS TO BE USED IN THE CASTING OF IRON OR OTHER METAL
Year: 1865

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields.
in the County of Middlesex, Gentleman, for the Invention of "A NEW
AND IMPROVED MODE OF MAKING AND VENTING CORES AND PARTS OF MOULDS TO
BE USED IN THE CASTING OF IRON OR OTHER METAL."-A communication
from abroad by Joseph Harrison, junior, of the City of Philadelphia, in
the State of Pennsylvania, United States of America, Engineer.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents, with his Petition, on the
25th May 1865.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said Invention
for "A NEW AND IMPROVED MODE OF MAKING AND VENTING CORES AND PARTS OF
MOULDS TO BE USED IN THE CASTING OF IRON OR OTHER METAL," a communication
to me from abroad, by Joseph Harrison, junior, of the City of Philadelphia,
in the State of Pennsylvania, United States of America, Engineer, to be as
follows:-
This Invention consists in forming cores and parts of moulds of moist sand
or other material for pipes or other castings on a perforated tube or other form
of any desired length or shape, such tube or other form having certain attach-
ments herein-after described, so that the effect of a vacuum may be obtained
in order to strengthen the core at the moment of casting, and at the same time
to rapidly take away from the core or mould the gases generated by the

page_text: molten metal, thus preventing the tendency to blowing or making imperfect
work. With any of the ordinary means one or both ends of the tube may be
attached to an air pump or to a vacuum chamber placed at a convenient
distance from the mould. When the casting is to be poured, the air pump is
first to be started, or the connection with the vacuum opened, which will
immediately cause the air surrounding the core to enter and permeate through
the sand, and to find at length an entrance into the tube through the per-
forations therein. As the metal rises under and around the core the gases
that are produced inside the core by the heat of the metal will be forced by
the effect of the vacuum into the tube, and thence discharged by the air pump,
or made to occupy the empty space in the vacuum chamber. The core is
thus much more effectually vented than when the gases are taken off in the
ordinary manner, whilst at the same time, in consequence of the partial
vacuum which takes place throughout the whole length of the core, the sand
forming the core is relieved of the pressure at or near its centre, the pressure
of the atmosphere being against its external surface; the whole core is much
strengthened, and a better class of casting is the result,
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 25th November 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of May, in the year of our Lord
One thousand eight hundred and sixty-five, in the 28th 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 "A NEW AND IMPROVED MODE OF MAKING AND VENTING CORES AND PARTS OF
MOULDS TO BE USED IN THE CASTING OF IRON OR OTHER METAL," a communication

page_text: to me from abroad, by Joseph Harrison, junior, of the City of Philadelphia,
in the State of Pennsylvania, United States of America, Engineer, upon the
condition (amongst others) that I, the said John Henry Johnson, my
executors or administrators, by an instrument in writing under my band and
seal, should particularly describe and ascertain the nature of the said Inven-
tion, 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 Letters Patent.
NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manuer the same
is to be performed, to be particularly described and ascertained in and by
the following statement, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon (that is to say):-
The said Invention consists in forming cores and parts of moulds of
moist sand or other material for pipes or other castings on a perforated
tube or other form of any desired length or shape, such tube or other form
baving certain attachments herein-after described, so that the effect of a
vacuum may be obtained in order to strengthen the core or mould at the
moment of casting, and at the same time to rapidly take away from the core
or mould the gases generated by the molten metal, thus preventing the
tendency to blowing or making imperfect work. With any of the ordinary
means one or both ends of the tube may be attached to an air pump or to a
vacuum chamber placed at a convenient distance from the mould. When the
casting is to be poured, the air pump is first to be started, or a connection with
the vacuum chamber opened, which will immediately cause the air surrounding
the core to enter and permeate through the sand, and to find at length an
entrance into the tube through the perforations therein. As the metal rises
under and around the core the gases that are produced inside the core by the
heat of the metal will be forced by the effect of the vacuum into the tube a,
and thence discharged by the air pump, or made to occupy the empty space in
the vacuum chamber. The core or mould is thus much more effectually
vented than when the gases are taken off in the ordinary manner, whilst at
the same time, in consequence of the partial vacuum which takes place
throughout the whole length of the core, the sand forming the core is relieved
of the pressure at or near its centre, the pressure of the atmosphere being
against its external surface; the whole core is much strengthened, and a
better class of casting is the result,
And in order that the said Invention may be fully understood, I shall refer
to the Drawing annexed, which represents a longitudinal sectional elevation of

page_text: a core constructed according to this Invention adapted for casting a pipe having
a series of spherical chambers or enlargement formed therein.
a is the perforated tube, provided with any convenient coupling or with a
union joint at each end for the facility of connecting it with an air pump or
vacuum chamber; b is the sand of the core, which is rammed round the
perforated surface of the tube a.
It is also intended to apply the same mode of venting and strengthening
moulds or other forms made of sand or other material for the purpose of
making castings where such moulds or forms might not be properly called
cores. I am aware that a method of exhausting moulds for molten metal or
plastic material, such as gutta percha and the like, by means of a vacuum has
been proposed for the purpose of obtaining a more correct product from the
mould, but the two methods have entirely different aims. In the former case
the moulds are made of metal or other solid material, and the sole object is to
exhaust the cavity of the mould by means of the vacuum whilst the plastic
material is being run into the mould; whereas according to the present
Invention no effort to exhaust the cavity of the mould is made, but it is left
in the usual manner open to the external air. These cores or moulds are
made of porous moist sand, or similar material, and the present object is to
convey away, by means of a vacuum, the gases that are always generated in
such material as these cores or moulds are made of whenever molten metal is
run into the cavity of the mould.
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 carried
into effect, I would observe, in conclusion, that 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, the mode of making, using, and
venting cores or moulds for castings, as above described, for the purpose of
strengthening them when made of weak moist sand or similar material, and
for the better venting the same by the use of a vacuum, as above described,
when the molten metal is poured into the moulds.
In witness whereof, I, the said John Henry Johnson, have hereunto set
my hand and seal, the Twenty-fourth day of November, One thousand
eight hundred and sixty-five.