IMPROVEMENTS IN GAS FURNACES SUITABLE FOR FUSING REFRACTORY METALS
Year: 1859

page_text: LETTERS PATENT to John Joseph Griffin, of 119 and 120, Bunbill Row,
in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
GAS FURNACES SUITABLE FOR FUSING REFRACTORY METALS."
Sealed the 15th November 1859, and dated the 29th June 1859.
PROVISIONAL SPECIFICATION left by the said John Joseph Griffin
at the Office of the Commissioners of Patents, with his Petition, on
the 29th June 1859.
I, JOHN JOSEPH GRIFFIN, of 119 and 120, Bunhill Row, in the County of
Middlesex, do hereby declare the nature of the Invention for "IMPROVE-
MENTS IN GAS FURNACES SUITABLE FOR FUSING REFRACTORY METALS," to be as
follows:-
This Invention has for its object improvements in gas furnaces suitable for
fusing refactory metals. For this purpose I employ a gas burner consisting
of a cylindrical or other suitably formed metal case closed at the bottom, and
having at the top a cover formed of a block of cast iron or other material
capable of sustaining a considerable heat. The case is also divided into two
compartments by a partition, into the upper compartment of the case coal gas
is admitted, and it escapes by holes bored in the cast-iron or other cover; into
the lower compartment of the case air is forced by bellows or other suitable
apparatus, and it passes from this compartment by tubes fitted into the partition,
these tubes are equal in number to the holes bored in the cover of the case,
and they pass up through these holes to the level of the upper surface of the

page_text: cover, leaving spaces around each of them for the escape of the gas. Thus, from
each hole in the cover a cylindrical jet of gas passes, having an air jet in its
interior, and when these jets are inflamed great heat is produced.
The burner constructed in this manner is fitted closely into a hole formed in
the centre of a slab of refractory pottery ware or other suitable material. On
the slab and over the burner a perforated cover is placed, in the top of which
is a hole for receiving a crucible, and over the crucible is another perforated
The space between this outer cover and the exterior wall of the
furnace is filled in by preference with small flint stones, which serve to keep
in the heat. The exterior wall of the furnace is formed of one or more rings
of refractory pottery ware or other suitable material, and is so arranged that
it, together with the outer cover and the packing of flints between them, may
all be raised together when required, so as to expose the crucible.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Joseph Griffin in the Great Seal Patent Office on
the 27th December 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
JOSEPH GRIFFIN, of 119 and 120, Bunhill Row, in the County of Middlesex,
send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of June, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Joseph Griffin, Her special licence that I, the said John
Joseph Griffin, my executors, administrators, and assigns, or such others
as I, the said John Joseph Griffin, 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 for
"IMPROVEMENTS IN GAS FURNACES SUITABLE FOR FUSING REFRACTORY METALS,"
upon the condition (amongst others) that I, the said John Joseph Griffin, 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 per-
formed, and cause the same to be filed in the Great Seal Patent Office within

page_text: six calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said John Joseph Griffin, 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 thereof, that is to say:
This Invention has for its object improvements in gas furnaces suitable for
fusing refractory metals. For this purpose I employ a gas burner consisting
of a cylindrical or other suitably formed metal case closed at the bottom, and
having at the top a cover formed of a block of cast iron or other material
capable of sustaining a considerable heat. The case is also divided into two
'compartments by a partition; into the upper compartment of the case coal
gas is admitted, and it escapes by holes bored in the cast iron or other cover;
into the lower compartment of the case air is forced by bellows or other
suitable apparatus, and it passes from this compartment by tubes fitted into
the partition. These tubes are equal in number to the holes bored in the
cover of the case, and they pass up through these holes to the level of the
upper surface of the cover, leaving spaces around each of them for the escape
of the gas. Thus, from each hole in the cover a cylindrical jet of gas passes,
having an air jet in its interior, and when these jets are inflamed great hent
is produced.
The burner constructed in this manner is fitted closely into a hole formed'
in the centre of a slab of refractory pottery ware or other suitable material.
On the slab and over the burner a perforated cover is placed, in the top of
which is a hole for receiving a crucible, and over the crucible is another per-
forated cover. The space between this outer cover and the exterior wall of the
furnace is filled in by preference with small flint stones, which serve to keep
in the heat. The exterior wall of the furnace is formed of one or more rings
of refractory pottery ware or other suitable material, and is so arranged that
it. together with the outer cover and the packing of flints between them may
all be raised together when required, so as to expose the crucible.
And in order that my said Invention may be most fully understood and
readily carried into effect, I will proceed to describe the Drawings hereunto
annexed..
DESCRIPTION OF THE DRAWINGS..
Figure 1 is a side elevation of a furnace constructed according to my
Invention; Figure 2 is a vertical section of the same. A is a burner, of
which the construction is clearly shown at Figure 3, which is a vertical section

page_text: of the same.
It consists of a cylinder a by preference of cast iron closed at
one end by a block of the same material b, which is cast in one piece with the
cylinder a, and is an inch or more in thickness; this block has a number of
holes bored through it, arranged as is shewn at Figure 4. The other end of
the cylinder a is closed by a cover c, which screws into it as is shown, and
which is furnished with a stem c' projecting from it, by means of which the
.burner may be held in a suitable foot, such as is indicated at B, in Figures 1
and 2, the foot carrying a socket, into which the stem of the burner fits, and
being furnished with a binding screw, by which the stem may be clamped so
as to hold the burner at any desired distance from the base. Within the
case a is a metal partition d, which divides it into two compartments, an upper
and a lower, and in this partition a number of small tubes e, e, by preference
of brass, are fixed one for each hole in the block b, and they pass up the centre
of these holes and terminate just below the upper surface of the block. The
upper compartment of the burner has a pipe f in communication with it, and
is connected by a flexible tube with a gas supply pipe of sufficient capacity.
The lower compartment of the burner has also a pipe communicating with it,
and which is connected by a flexible tube with bellows to supply air under
pressure. The gas admitted to the upper compartment of the burner escapes
by the holes in the block 6 at the top, sufficient space being left around the
small tubes e, e, for the purpose. The air admitted to the lower compartment
of the burner escapes through the tubes e, e, so that each jet of air passes up
into the interior of a jet of gas. The size of the burner will depend to some
extent on the size of the furnace with which it is to be employed. For a
furnace of which the internal diameter is six or eight inches, I have found a
burner having sixteen jets to be suitable. The holes in the block 6 of such a
burner I make inch in diameter, and the tubes e of 1 inch interior diameter,
and of metal of about No. 24 of the wire guage. The gas and air supply
pipes should be about one inch internal diameter, and the bellows for forcing
the air should be so weighted as to supply it at a pressure about ten times that
of the gas employed. The gas with which I have usually worked has been of
a pressure of about half an inch of water, but this may be increased with
advantage. The gas pipe should be furnished with a stop-cock, by means of
which the quantity of gas passing to the burner may be regulated until the
best effect is obtained. I would remark that I am aware that gas burners of
a somewhat similar construction have before been employed, but in such
burners as heretofore made, the gas jets escape from tubes of comparatively
thin metal, but such burners will not stand when enclosed in a furnace, as the
tubular jets become burnt. The important feature of my burner is that the

page_text: upper part is formed of a mass of comparatively refractory material, by pre-
ference of cast iron, in which holes are bored or formed. Burners so.formed
do not for a long time become injured by the heat of the furnace. The burner,
as the Drawing Figure 2 shows, is placed in the centre of a tripod g, which
supports a slab h made of fire-clay and burnt like a fire-brick, and which is
surrounded with a band of hoop iron to prevent it falling to pieces when
cracked by the heat; the slab has a hole at its centre into which the upper
part of the burner fits. Resting on the slab h is a second slab i of a similar
description, but having a larger hole at its centre; it has a flange at its edge,
under which a metal ring j rests, and this ring has two bars k, k, fixed to it,
by means of which it and the parts above it which it supports can be lifted
when desired. On the lower slab h a cylinder of plumbago 7 rests; the sides
of which are perforated with numerous holes as is shown; it serves as a
support to a flanged crucible 'm, over the crucible a dome n is placed, it rests
on the second slab i, and at its lower part is also perforated with numerous
holes. External views of the parts and n are shewn at Figures 5 and 6.
On the slab i also rest one above the other two cylinders of fire-clay o and p,
they are bound with hoop iron and are furnished with view holes, through
which the state of the interior of the furnace may be observed when desired.
These view holes are marked 9, 9, and are furnished with suitable plugs or
stoppers. The interior of the furnace over the dome n. is filled with flint
pebbles from one half an inch to an inch in diameter. The pebbles should be
water worn or rounded, and washed clean from earth and clay. When the
furnace is in use these pebbles serve to retain the heat around the crucible, they
become white hot, while the gases and vapours escape at the top of the furnace
in a comparatively cool state, so cool, indeed, that the hand, may be held just
over the top of the furnace without injury. A furnace of this description
when burning one hundred cubic feet of gas per hour will melt eight or ten
pounds of cast iron within an hour. When it is desired, when using a furnace
of this description, to examine the crucible to see how the operation is pro-
gressing, the upper part of the furnace is raised by the bars k, k, and, if found
necessary, it may then be immediately replaced without materially lowering the
temperature.
:
Figure 7 is a longitudinal section of a furnace of a somewhat simpler con-
struction, in which no arrangement is made for raising the body of the furnace
from the crucible. The slab i to which the lifting bars are attached, and the
domen for supporting the pebbles over the crucible are omitted, and the
pebbles rest directly on the crucible cover. This form of furnace may be
advantageously employed when the same operation is to be frequently repeated,

page_text: and when the exact duration of blast necessary to produce the result is
known.
Figure 8 is a longitudinal section of another arrangement in which the
burner is inverted and introduced at the top of the furnace; this construction
is very convenient in furnaces of small size. In this furnace a second slab of
fire-clay similar to the slab h of Figures 1 and 2 is employed to close the top
of the furnace, and the burner is fitted into the hole at its centre. The hole
in the lower slab is closed by the cylinder r, a side view of which is shown at
Figure 9. This cylinder is closed at its upper end, and has a number of holes
formed in its sides, it supports two or other convenient number of fire-clay
discs 8, 8, employed to raise the crucible to the proper level, the crucible stands
on the upper disc, and is surrounded by a cylinder t, shown separately at
Figure 10. The space between the interior of the sides of the furnace and
the pile in the centre of the furnace is filled in with pebbles as before. When
this form of furnace is employed, it is advantageous to use an open crucible,
if the material to be operated on is such as not to be injured by a current of
air being thrown on it when in a heated state.
When a burner of the size herein specified is made use of, the top or the
bottom of the crucible, as the case may be, should be placed at a distance of
from two to two and a half inches from the block 6 of the burner. I would
remark that the form of the furnace and the form of the burner may both be
greatly varied without departing from my Invention. A cylindrical furnace
and burner I consider most convenient for general purposes, but should the
article to be heated be rectangular or of other form, it may in some cases be
desirable to employ a furnace of corresponding shape. In some cases also it
is desirable to introduce a burner or burners at the side of the furnace.
In witness whereof, I, the said John Joseph Griffin have hereunto set
my hand and seal, this Twenty-first day of December, in the year of
our Lord One thousand eight hundred and fifty-nine.
JOHN JOSEPH GRIFFIN. (L.S.)