IMPROVEMENTS IN THE MANUFACTURE OF GAS RETORTS AND OTHER ARTICLES DAD DE CANEM AND FOR OTHER
Year: 1865

page_text: LETTERS PATENT to William Schofield, of Heywood, in the County of
Lancaster, Manager of the Heywood Gas Works, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF GAS RETORTS AND OTHER ARTICLES
DAD DE CANEM AND FOR OTHER
Sealed the 12th December 1865, and dated the 30th June 1865.
PROVISIONAL SPECIFICATION left by the said William Schofield at the
Office of the Commissioners of Patents, with his Petition, on the
30th June 1865.
I, WILLIAM SCHOFIELD, of Heywood, in the County of Lancaster, Manager
of the Heywood Gas Works, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN THE MANUFACTURE OF GAS RETORTS AND OTHER
ARTICLES MADE OF FIRE-CLAY, AND IN FURNACES FOR BURNING THE SAME, AND
FOR OTHER PURPOSES," to be as follows:-
In manufacturing gas retorts it has heretofore been customary to mould
and cast them in solid fire-clay, and such retorts when in use are very liable
to contract and to crack.

page_text: Now my Invention consists in moulding and casting the retorts with
a number of perforations distributed over the surface, or the perforations
may be made after the retort is moulded; the retorts are then burnt in
the usual manner or according to my improvements, as herein-after described,
and the perforations are then filled up with burnt blocks of fire-clay and
cement.
My Invention also consists in securing the mouth-pieces of retorts to the
retorts by screws taking into threads formed of and in the fire-clay. The
improved mode of manufacturing retorts of fire-clay with perforations above
described, is also applicable in making fire-door tiles, baffle plates, and other
articles of fire-clay that are exposed to great variations of temperature.
My improvements in furnaces consist in making the furnace bars to
rotate or oscillate on their axes, to prevent the adhesion of clinkers and injury
to the bars, and to promote the combustion of the fuel. The bars are circular,
or with projections and recesses, so that in revolving or moving the space
between them remains about the same. The ends of the bars are connected
by pinions, or by a worm and wheels, so that they may all be moved simul-
taneously, or they may be moved individually by hand without gearing.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Schofield in the Great Seal Patent Office on 2
the 27th December 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
SCHOFIELD, of Heywood, in the County of Lancaster, Manager of the Heywood
Gas Works, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of June, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Schofield, Her special license that I, the said William
Schofield, my executors, administrators, and assigns, or such others. as
I, the said William Schofield, my executors, administrators, and 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

page_text: for "IMPROVEMENTS IN THE MANUFACTURE OF GAS RETORTS AND OTHER ARTICLES
MADE OF FIRE-CLAY, AND IN FURNACES FOR BURNING THE SAME, AND FOR OTHER
PURPOSES," upon the condition (amongst others) that I, the said William
Schofield, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, 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 Letters Patent.
NOW KNOW YE, that I, the said William Schofield, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement (that is to say):
In manufacturing gas retorts it has heretofore been customary to mould and
cast them in solid fire-clay, mixed with ground burnt fire-clay or other mate-
rials, and such retorts when in use are very liable to contract and to crack.
Now, my Invention consists in moulding and casting the retorts with a number
of perforations distributed over the surface, or the perforations may be made
after the retort is moulded; the retorts are then burnt in the usual manner or
according to my improvements, as herein-after described, and the perforations
are then filled up with burnt blocks of fire-clay and cement. My Invention
also consists in securing the mouth-pieces of retorts to the retorts by screws
taking into threads formed of and in the fire-clay. The improved mode of
manufacturing retorts of fire-clay with perforations, above described, is also
applicable in making crucibles, fire-door tiles, baffle plates, and other articles
of fire-clay that are exposed to great variations of temperature. My
improvements in furnaces consist in making the furnace bars to rotate or
oscillate on their axes, to prevent the adhesion of clinkers and injury to the
bars and to promote the combustion of the fuel. The bars are cylindrical
or with projections and recesses, so that in revolving or moving the space
between them remains about the same. The ends of the bars are connected
by pinions, or by a worm and wheels, so that they may all be moved simul-
taneously, or they may be moved individually by hand without gearing. And in
order that my Invention may be fully understood and readily carried into
effect, I will proceed to describe the accompanying Sheet of Drawings,
reference being had to the figures and letters marked thereon.
.
Figure 1 is a longitudinal section of a gas retort constructed according to
my improvements; Figure 2 is an end view of the mouth-piece of the retort;
Figure 3 is a transverse section of the retort. The body of the retort is

page_text: moulded or cast of mixed, burnt, and raw fire-clay in the ordinary manner,
but the outer case of the mould is made with perforations corresponding in
number and position to the perforations required in constructing the retort.
According to my improvements in Figure 1 some of these perforations are
shown, but it is evident that the perforations are made by preference all over
the surface of the retort; the number and diameter of the perforations may be
varied. When the retort is being moulded over a short core of the usual
construction it is customary to remove the outer case and the inner core, and
to leave the portion of the retort thus moulded for several days, in order that
the fire-clay may have time to set before the next portion is added. When
the fire-clay is being. rammed in the air which is combined with it escapes
through the perforations in the mould, thus increasing the solidity of the retort,
the clay also exudes partly through the perforations in the outer mould or case,
and the perforations are made through the retort by forcing a hollow-cylin-
drical instrument, made of very thin iron or steel, through the perforations in
the mould and through the fire-olay. The cylindrical blocks cut-out by the
perforating instrument or other blocks are burnt in a kiln and serve as plugs
to fill up the perforations, or the perforations may be made conical and taper
plugs fitted into them. It has heretofore been customary to keep the upper
portion of the fire-clay of the partially formed retort moist by means of wet
rags, but by means of the instrument shewn in Figures 4 and 5 these wet rags
may be dispensed with. The instrument consists of a sheet metal trough or
cap of the shape of the retort; this cap is put on the top of the partially
formed retort as soon as the portion has been moulded, and by excluding the
atmosphere the fire-clay retains its desired moisture for adhering to the fire-
clay that is rammed into the mould after the core has been moved to form the
next portion of the retort. When the whole retort has been moulded and the
perforations made in it, as described, it is burnt in a kiln of the usual con-
struction, or provided with my improved furnace, hereafter described. The
cylindrical blocks or portions of fire-clay that are cut out to form the perfora-
tions in the retort are also burnt in a suitable furnace, and they are afterwards
cemented into the perforations to make the retort perfectly tight; these blocks
may fill up the whole length of the perforation; or only part thereof, as shewn
in Figure 3, and if preferred a thread may be tapped in the fire-clay and the
plug may have a thread cast on it; in this case the plugs would be screwed
into the retort. When a compound core of the entire length of the retort, as
described in the Specification of Letters Patent granted to Orlando Brothers on
the Nineteenth day of August, One thousand eight hundred and forty-seven,
Number 11,840, is employed, the outer mould or case is made in lengths, and

page_text: with perforations, as before described, the retort is moulded by ramming the
fire-clay into each length in succession continuously, without allowing one
portion of the retort to dry before the next portion is added; the perforations
are then made, when the whole retort is moulded. Retorts constructed in the
manner above described may be used in: generating gas, without supports in
the gas furnaces, such retorts being so much stronger. than those of the
ordinary construction that they will bear their own weight from end to end
when made of the usual length. I wish to observe that instead of making
the perforations in the retort forcing an instrument through the holes in the
outer case, the outer case may be constructed as usual, and the perforations
made in the retort after the outer case and inner core are removed.
: .
In Figures 1 and 2 I have shewn my improved. mode of securing the mouth-
piece marked b to the end of the retort. When the retort has been moulded
and the fire-clay has had time to set, but before it has been burnt, I make six
or other convenient number of holes in the body of the fire-clay, forming the
end of the retort, and these holes are, then tapped with a tap similar to that
shewn full size in Figure 6; by turning this tap round in the direction: of the
arrow the fire-clay is gradually displaced, until a perfect screw-thread is formed
in and by the fire-clay, and into these threads when burnt the set screws a are
screwed, thus holding the mouth-piece b securely. against the end of the retort,
or a screw bolt may be embedded in the fire-clay when being moulded; and
screwed out afterwards, thus leaving the hole, screwed. This improved:mode
of securing the mouth-piece to the retort may be applied to retorts of the
ordinary construction; ; the length of the screw bolts is by this means so much
reduced that the expansion of the bolts does not break the joint of the mouth-
piece, and the bolts are not injured by the heat. In Figures 7 and 8 I.have
shewn a section and plan of a crucible, constructed according to my improve-
ments, and the apparatus for moulding the same; c is the outer. mould or.box,
which is made by preference in two parts to facilitate the removal of the
crucible; the outer mould is perforated as shewn partly in the Drawing or
in any other convenient manner;; d is the core which is guided below by.the
stud e passing through a hole in the bottom of the outer mould, and above, by
the three hooks f.: When the mixed, raw, and burnt-fire-clay has been placed
in the inside of the mould c, the core d is introduced and gradually.forced
down by a lever or other equivalent to compress the fire-clay between the:core
and the mould; this pressure on the core causes the surplus fire-clay to exude
into the perforations in the mould c; but in order to consolidate, the clay.forming
the crucible I prefer to place the mould c in an outer sheet metal case, w
.which
would prevent or moderate the escapo of the exuding fire-clay. When the

page_text: crucible is moulded, as above described, and the outer case removed, the
requisite holes are made in the crucible by means of a thin metal tube, as
described in reference to Figure 1; the core d is then taken out, but before
the crucible is taken to the furnace to be burnt it is desirable to make the
perforations slightly conical, as shewn in Figure 7, and this can be done by
introducing into the holes a taper plug from the inside of the crucible; when
the crucible has been burnt these conical holes are filled up with conical blocks
and cement, by this means the plugs cannot be forced out by the pressure of
the melted metal in the crucible. In Figures 9 and 10 I have shewn two
views of a furnace constructed according to my improvements; these improve-
ments are applicable to furnaces for generating steam and to other furnaces;
9 is the frame for the fire-door h, the lower part of the frame 9 supports the
front ends of the fire-bars i, a similar support being provided for them near
the bridge, the fire-bars are shewn round, but they may be made with projec-
tions and recesses; to each fire-bar is fixed a pinion j, and all these pinions
gear into the worm k, to which a slow rotary motion is imparted by any suit-
able gearing, or by hand; by this means the fire-bars are turned gradually
round on their axes, thus preventing injury by the adhesion of clinkers, and
promoting the combustion of the fuel. The pinions j and the worm k are
protected from the dust and cinders by the guard l'cast or fixed to the frame
gor secured in any other convenient manner. In some cases the worm k and
pinions may be dispensed with, and the fire-bars turned round occasionally
by the attendant; in this case each fire-bar is made with a square hole in which
a key is introduced, or the pinions"; may all be geared into each other, or an
oscillating motion may be given to the bars instead of a rotary one. To the
door h is fixed a fire-resisting tile m, which is made with plugged-up perfora-
tions, as described in reference to the gas retort and crucible. I wish to observe
that although I have only shewn and described my improved mode of con-
structing articles of fire-clay in order to prevent them cracking and breaking,
as applied to retorts, crucibles, and fire-door tiles, yet it is evident that my
improvements are applicable to every other article made of fire-clay that may
be exposed to intense heat and to great variations in temperature.
Having thus stated the nature of my Invention, and described the manner'
of performing the same, I declare that I claim,-
First, the improved mode described of manufacturing articles of fire-clay or
fire-clay combined with other materials, and the apparatus shewn and described
when employed for that purpose.
. Secondly, the modes described of making screw-threads in articles of fire-
clay.

page_text: And, lastly, the improved furnace described with rotating or oscillating
grate bars.
In witness whereof, I, the said William Schofield, have hereunto set
my hand and seal, this Twenty-third day of December, One thousand
hundred and sixty-five.
W. SCHOFIELD. (L.S.)