AN IMPROVEMENT IN THE MANUFACTURE OF FIRE-BRICKS, FIRE-CEMENT, AND FIRE-WARE GOODS GENERALLY
Year: 1878

page_text: LETTERS PATENT to Henry Edwards, of Braich y Cymmer, in the Parish of
Bettws, in the County of Glamorgan, for the Invention of "AN IMPROVEMENT
IN THE MANUFACTURE OF FIRE-BRICKS, FIRE-CEMENT, AND FIRE-WARE GOODS
GENERALLY"
Sealed the 8th November 1878, and dated the 27th August 1878.
PROVISIONAL SPECIFICATION left by the said Henry Edwards at the Office
of the Commissioners of Patents on the 27th August 1878.
HENRY EDWARDS, of Braich y Cymmer, in the Parish of Bettws, in the County of
Glamorgan. "AN IMPROVEMENT IN THE MANUFACTURE OF FIRE-BRICKS, FIRE-
CEMENT, AND FIRE-WARE GOODS GENERALLY."
This Invention relates to an improvement in the manufacture of fire-bricks, fire-
cement, and fire-ware goods generally by the mixture of calcined flint and calcined
limestone, or as it is commonly called burnt lime, whereby fire-resisting articles can
be made, consisting almost entirely of silica.
I am aware that flint has been used before in the manufacture of fire-bricks, but
I believe invariably in combination with clay alone or clay and calamine.
I am also aware that lime has been used before in the manufacture of fire-bricks,
in combination with what is known as Dinas rock and other substances, but not in
connection with flint.
I have found that fire-bricks made by a combination of flint and clay combined,
and flint, clay, and calamine combined, are not satisfactory fire-resisters, because in
great beats the clay being weaker than the flint melts and runs out of the brick,
leaving the flint portion of the brick as it were honeycombed, besides which the
clay acts as a flux upon the flint itself, so that even the fint portion of the brick
melts much sooner than it would have done had the clay not been with it.
My process of manufacture is as follows:-The flint stones are deposited in an
open kiln mixed with coal dust or small coke, or what is commonly known as
breeze, and the kiln being fired the flint is thoroughly calcined. From the kiln the
calcined flint is conveyed to a crushing machine, such as the machine known a
Prins A31

page_text: "
Blakes," which crushes it; the crushed flint is then introduced into a fixed pan
in which revolves a pair of heavy edge-runners. The limestone, preferably what is
known as mountain limestone or Aberthaw limestone is also burned in a kiln in
the usual manner, and deposited in a tank, into which tank water, hot or cold,
preferably hot, is also introduced, and the burnt lime is thereby partially dissolved.
This water, in which the lime has been partially dissolved, is run into another
tank, and then allowed to settle, and a proportion of the lime deposits at the
bottom of such tank. When the water is nearly clear it is conveyed by pipes or
launder to the pan of the edge-runners before named, in which the flint has been
deposited, enough of such nearly clear lime water being introduced to moisten the
flint sufficiently for a thorough mixing. The revolving runners grind and
thoroughly mix the mass, taking ordinarily about a quarter of an hour for each
charge of, say, one ton of flint and limo water.
The flint is not necessarily ground to powder, lumps of flint as large as filberts
not being deleterious to the fire-brick; but the amount of grinding is regulated
according to the articles intended to be produced; for instance, for fire-cement, and
for crucibles and other fine goods, the flint should be ground considerably finer than
that for larger articles, such as bricks, slabs, &c.
When the mass is ground and mixed sufficiently for the purpose for which it is
intended it is removed from the pan through a sluice in the bottom thereof.
The plastic composition thus formed may be at once moulded into bricks, but it
will be improved and brought to better temper if kept for 24 or 36 hours before
moulding.
The proportion of lime introduced in this manner into the mixture should not
exceed three per cent., that is to say, there should not be more than three parts of
lime to ninety-seven parts of flint, the object of the lime being simply to make the
composition adhesive and uphold the moulded articles, and enable them to be set
in the kiln one above another, and to hold the flint together during the process of
baking.
The moulding, drying, and baking may be done in the manner usual in the
manufacture of the Dinas fire-brick or stone fire-bricks generally.
The fire-cement is brought into fit condition for sale by drying the plastic com-
pound above described after it leaves the pan, and regrinding same when dry. It
is then ready to be packed in bags or casks.
The object of the use of the lime in the fire-cement is to render it plastic and
pliable on the addition of sufficient water when required for use by the bricklayer,
the addition of the water restoring it to the condition in which it originally left the
edge-runners.
By this improved compound I am able to produce fire-ware goods and fire-cement
consisting of nearly pure silica, quite as capable, and I believe more capable of
resisting heat than even the famous Dinas fire-brick or any known fire-brick, and
which will not swell in the furnace as the Dinas fire-brick does.
I particularly lay stress on the fact that I only use the lime to make the com-
position plastic and binding, and that I prefer to use the smallest proportion of lime
that will sufficiently achieve this result and enable the moulded articles to be
baked hard in the kiln.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the maid Henry Edwards in the Great Scal Patent Office on the 25th February
1879.
HENRY EDWARDS, of Braich y Cymmer, in the Parish of Bettws, in the County of
Glamorgan. "AN IMPROVEMENT IN THE MANUFACTURE OF FIRE-BRICKS, FIRE-
CEMENT, AND FIRE-WARE GOODS GENERALLY."
This Invention relates to an improvement in the manufacture of fire-bricks, fire-
cement, and fire-ware goods generally by the mixture of calcined flint and calcined
limestone, or as it is commonly called burnt lime, whereby fire-resisting articles can
be made, consisting almost entirely of Bilica.
I am aware that flint has been used before in the manufacture of fire-bricks, but
I believe invariably in combination with clay alone or clay and calamine.
I am aware also that lime has been used before in the manufacture of fire-bricks,
in combination with what is known as Dinas rock and other substances, but not in
combination with flint.
I have found that fire-bricks made by a combination of flint and clay combined,
and flint, clay, and calomine combined, are not satisfactory fire-resisters, because in
great heats the clay being weaker than the flint melts and runs out of the brick,
leaving the flint portion of the brick, as it were, honeycombed, besides which the
clay appears to act as a flux to the flint itself, so that even the flint portion of
the brick melts sooner than it would have done had the clay not been with it.
"
My process of manufacture is as follows:-The flint stones are deposited in an
open kiln mixed with coal dust or small coke, or what is commonly known as
breeze, and the kiln being fired the flint is thoroughly calcined. From the kiln the
calcined flint is conveyed to a crushing machine, such as the machine known as
Blakes," which crushes it; the crushed flint is then introduced into a fixed pan,
in which revolve a pair of heavy edge-runners. The limestone, preferably what is
known as mountain limestone or Aberthaw limestone, is also burned in a kiln in
the usual manner and deposited in a tank, into which tank water, hot or cold, pre-
ferably hot, is also introduced, and the burnt lime is thereby partially dissolved.
This water, in which the lime has been partially dissolved, is run into another
tank, and there allowed to settle, and a proportion of the lime deposits at the
bottom of such tank. When the water is nearly clear it is conveyed by pipes or
launder to the pan of the edge-runners before named in which the flint has
been deposited, enough of such nearly clear lime water being introduced to moisten
the flint sufficiently for a thorough mixing. The revolving runners grind and
thoroughly mix the mass, taking ordinarily about a quarter of an hour for each
charge of, say, one ton of flint and lime water.
The flint is not necessarily ground to powder, lumps of flint as large as filberts
not being deleterious to the fire-brick; but the amount of grinding is regulated
according to the articles intended to be produced; for instance, for fire-cement, and
for crucibles and other fine goods, the flint should be ground considerably finer than
that for larger articles, such as bricks, slabs, &c.
When the mass is ground and mixed sufficiently for the purpose for which it is
intended it is removed from the pan through a sluice in the bottom of the pan.
The plastic composition thus formed may be at once moulded into bricks, but it
will be improved and brought to better "temper" if kept for twenty-four or thirty-
six hours before moulding.
The proportion of lime introduced in this manner into the mixture should not
exceed three per cent. of the mixture, that is to say, there should not be more than
three parts of lime to ninety-seven parts of flint, the object of the lime being simply
to make the composition adhesive, and uphold the moulded articles, and enable them
to be set in the kiln one above another, and to hold the flint together during the
process of baking,

page_text: The moulding, drying, and baking of the various goods may be done in the
manner usual in the manufacture of the Dinas fire-brick or stone fire-bricks
generally.
The fire-cement is brought into fit condition for sale by drying the plastic com-
pound above described after it leaves the pan, and regrinding same when dry. It
is then ready to be packed in bags or casks.
The object of the use of the limo in the fire-cement is to render it plastic and
pliable on the addition of sufficient water when required for use by the bricklayer,
the addition of the water restoring it to the condition in which it originally left the
edge-runners.
By this improved compound I am able to produce fire-ware goods and fire-cement
consisting of nearly pure silica, quite as capable, and I believe more capable of
resisting intense heat than oven the famous Dinas fire-brick, or any known fire-brick,
and which will not swell in the furnace as the Dinas fire-brick does,
I particularly lay stress on the fact that I only use the lime to make the com-
position plastic and binding, and that I prefer to use the smallest proportion of lime
that will sufficiently achieve this result, and enable the moulded articles to be
baked hard in the kiln.
Having now set forth the nature of my Invention of an improvement in the
manufacture of fire-bricks, fire-cement, and fire-ware goods generally, and explained
the manner of carrying the same into effect, I declare that I claim, the use of lime
in combination with flint, for the purpose above described.
In witness whereof, I, the said Henry Edwards, have hereunto set my hand and
seal, this Twenty-second day of February, One thousand eight hundred
and seventy-nine.
HY. EDWARDS. (L.S.)