IMPROVEMENTS IN FURNACES APPLICABLE TO THE MELTING OF METALS FOR MAKING BRASS, YELLOW METAL, AND OTHER COMPOUND METALS
Year: 1851

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
FREDERICK MUNTZ, junior, of Birmingham, in the County of Warwick,
Gentleman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her.
Royal Letters Patent under the Great Seal of the United Kingdom of
Great Britain and Ireland, bearing date at Westminster, the Eighteenth day
of January, One thousand eight hundred and fifty-one, in the fourteenth year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said George Frederick Muntz, my exors, admors, and assigns, Her
especial licence, full power, sole privilege and authority, that I, the said
George Frederick Muntz, my exors, adiñors, and assigns, or such others as I,
the said George Frederick Muntz, my exors, admors, or 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, exer- .
cise, and vend, within England, Wales, and the Town of Berwick-upon-Tweed,
my Invention of "IMPROVEMENTS IN FURNACES APPLICABLE TO THE MELTING OF
METALS FOR MAKING BRASS, YELLOW METAL, AND OTHER COMPOUND METALS;" in
which said Letters Patent is contained a proviso that I, the said George
Frederick Muntz, shall cause a particular description of the nature of my
said Invention, and in what manner the same is to be performed, by an instru-
ment in writing under my hand and seal, to be inrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately

page_text: after the date of the said in part recited Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
George Frederick Muntz, do hereby declare that the nature of my said Inven-
tion, and in what manner the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had
to the Drawings hereunto, annexed, and to the figures and letters marked
thereon; that is to say:
My Invention consists in the construction of a furnace (applicable to the
melting of metals for making brass, yellow metal, and other compound metals
subject to be volatilized,) of which that part containing the metal is capable of
being converted into a close chamber; or nearly close, during the time the
metal is being mixed or stirred, the object of which is to prevent a great pro-
portion of the loss which would arise from volatilization in mixing such metal
in the description of furnace in ordinary use previous to the date of my
Invention, and to effect which I construct a furnace fitted with dampers or
moving partitions, one fitted in the bridge to close or open the passage
between the fire and the metal, the other between the metal and the chimney.
I also construct an additional flue or passage (fitted with a damper) con-
necting the fire with the chimney. The damper in this flue, and the damper
in the bridge before mentioned, are moved by a beam or lever, one being fixed
on each end; and so are made to balance each other: see A and B, Figure 1
on the Drawing. The other damper is fitted horizontally in the front flue,
sliding in a groove: see C, Figures 1 and 2. The charge of metal being
melted, and hot enough to mix or pour, the lever D, Figure 1, should be
drawn down by the rod E. The damper in the bridge by that means (being
connected with the other end of the lever by the rod B) is raised, thereby
closing the passage between the fire and the metal; but the damper attached
to the rod A (being on the same end of the lever as the rod E) is lowered,
and the passage opened between the fire and the chimney, so that the smoke
and heat from the fire is by that means carried away through the additional
flue without coming in contact with the metal. The damper C, Figure 2,
must then immediately be pushed along the groove D, till the flue E' is closed.
The part of the furnace containing the metal will then be close, and the
workman may open the door F, and mix or stir the contents as he thinks
well, with a much less loss of the volatile-metal than would take place in an
ordinary furnace. As soon as the metal is taken out of the furnace the
dampers should be moved to their original positions.
A
The only difference between my furnace and the reverberatory furnace in

page_text: general use is, the addition of the three dampers or moveable partitions, and
the additional flue' connecting the fire with the chimney without passing
through the reverberatory. I shall, therefore, only describe how these addi-
tions should be constructed, and how the alterations in those parts of the
furnace connected with them should be made; in other respects the furnace
should be constructed in the same manner as those now in general use.
י',
The bridge damper, see Figure 5, and A, Figure 3, is the inost difficult to keep
in repair, on account of the great heat to which it must necessarily be exposed.
It should be constructed of a cast iron frame, in which large bricks (composed
of Stourbridge clay and other materials, such as are used by the Stourbridge fire
brick maker in fire bricks made for ordinary purposes, and which should be made
about 18 inches by 9 inches x 4 inches,) are fixed. These bricks are fastened
in a
a groove in the uprights A, A. The bricks B and C being fixed, a wrought
iron rod is let into a groove in the centre of the top of B, and passing through
holes in A, is rivetted at each end. It should be put in at a red' heat, so that
the contraction which takes place in cooling may hold the uprights firmly
against the bricks. Afterwards the bricks D. may be fixed in tightly with
some cement clay. The cast iron frame should be made in one piece as far as
E, where wrought iron rods should be attached to connect it to the cross bar
F, by which it is connected by the rod G, Figure 5, and B, Figure 1, to the
lever.
"
1.
an
Figure 4 represents a section of the furnace cut through the groove in the
bridge in which the damper works. A is the passage from the grate or fire
into the melting part; B, the groove into which the damper slides when closing
the
passage; C, the recess in the bridge into which the damper is lowered when
the passage is opened; D, the holes or chambers through which the rods which
raise the damper work; E, brickwork (also see K, Figure 7,) reaching across
the groove and recess to keep the heat from the lifting rods when the damper
is down; F; brickwork cramped together by the iron cramp G, so as to make
an even surface above the damper keeping the bricks in place without
arch being turned. These bricks are seven inches wide, the arched roof of the
furnace joining each side, and being lower than the cramped bricks from
groove, as shewn in Figure 3, B. The brickwork in the bridge damper, see
D, Figure 5, must reach above the cast iron frame, so that the heat may not
injure the iron: see C, Figure 3." The top of this brickwork must be made
sharp, as shewn in the Drawing, in which case it is ill not be so likely to stick
to the roof of the furnace when drawn up, the surface coming in contact being
much reduced compared to what it would be if the top were made flat. This
damper should never be pressed hardly against the roof by being drawn up so
a

page_text: far, or it will stick, and the bricks D, Figure 5, may be torn from their places;
to prevent this stops must be placed so as to allow the damper to touch the
roof barely; these stops should be adjusted when the furnace is cold, so as to
allow the bricks in the damper to touch the roof of the furnace (videlicet, that
part of the roof fastened or contained in the iron cramp before described)
within one eighth part of an inch. The stops I have used are shown in
Figure 1, F, F; they are secured to the furnace, and extending over the cross
bar G, Figure 1, F, Figure 5, and A, Figure 6, prevent it from rising above
the height required. The stops must be fastened very securely, so that they
cannot spring or yield, or they will not answer the purpose. Any other con-
trivance to prevent the damper rising higher than required would answer the
purpose. The rods H, H, Figure 5, raise and lower the damper, and move
in the chambers D, D, Figure 4 and Figure 7; the tops of these chambers are
covered with iron plates, in which are holes through which the rods move, but
fit close enough to prevent any quantity of air injurious to the working
of the furnace from being admitted; the plates are only confined in their
places by the rods and their own weight, and should not be otherwise fastened
or they will most likely prevent the damper from moving easily when it becomes
hot. Great care should be taken to build the furnace so as to allow plenty of
room for the dampers in the grooves or recess, or they will not move when the
furnace is heated. I have made my Drawings in the proportions required,
and, being drawn to a scale of one inch to each foot, the workman can build a
correctly proportioned furnace from them. To make the dampers fit closely
the wall or groove should incline an inch in thirty-six inches out of perpendicular
towards the grate, and the lever should be so placed that the damper may hang
close to that side of the groove next the grate. It will sometimes happen that
the bricks in the bridge will run down in slag between the damper and the
side of the groove or recess, and cement it so that the damper cannot be moved;
this may generally be avoided by moving the damper about every hour when
the furnace is at full working heat, and oftener if colder, which will break off
the pieces of slag before they have time to accumulate or become hard; but, in
case this is not found to have the effect, a brick should be taken out of the
walls and partition H and E, Figure 4, about level with the top of the bridge,
through which an iron bar may be introduced and any obstruction removed.
The damper in the additional flue leading direct from the grate to the chimney
is constructed exactly in the same manner as the bridge damper, but the fire
only passing through that flue while the metal is being mixed, it is not exposed
to so much heat, and, therefore, more easily kept in repair; the proportions of
the groove and flue are shown in the Drawing, and the damper should be made

page_text: the groove in which it works, see D,-Figures 2 and 3. This groove is made
of brick work, and should be cramped with an iron cramp or frame, see H,
Figure 2, reaching over G and E, which are only left open in the Drawing to
show the interior of the flue. The groove should be made much deeper than
the damper (see Drawing) so that the clay and slag which runs down from
the flue may be cleared off easily. The groove should be made long enough
to allow the damper to be drawn about three feet from the flue, or it will not
cool during the time it is not in use, and will burn or melt when pushed in.
The end of the groove through which the handle works should be covered
with an iron plate, with only a hole to allow the handle or rod to pass, and so
prevent more air than can be avoided from being admitted. The other end of
the groove is stopped. by bricks cramped together with iron, in which is fixed
a handle, see J and K, Figure 2. These bricks should be pushed in so as to
fill the groove as far as the flue, or the furnace will not draw or work well,
.but they should always be drawn out to the position shewn in the Drawing
when the damper is pushed in or the heat of the bricks will injúre the iron.
A piece of sheet iron should be fixed between the bricks and the iron cramp
large enough to cover the opening at the end of the groove, so that when the
bricks are pushed in it may prevent air from being admitted. If the groove is
found to become foul or uneven a wrought hoop or band may be put round the
damper so as to project about a quarter of an inch. below the bottom; this will
be found to keep the groove cleaner and more 'even. The door through
which the metal is mixed should be made as small as possible, so as to prevent
(as much as possible) the atmosphere from being admitted, which would
cause the metal to volatilize and waste, and also annoy the workman. If a
large opening is required to admit the charge, a door may be used with a
smaller door in it through which to stir the metal: see Figure 2, G and F.
If the wind blows strongly into the ash hole, it should be covered over with
a sheet iron door, fitting tight during the time the dampers are used, or it
will penetrate between the joints into the furnace and cause the métal to
waste. The other parts of the furnace not otherwise described should be made
in the ordinary manner. The grate in the Drawing is made for using Staf-
fordshire coal; if any other is used it should be altered accordingly to suit the
fuel as in any ordinary furnace.
What I claim as my Invention is, the construction of a furnace for the
melting and mixing of metals for making brass and other compound metals
(in which zinc forms a part) which will allow such metals, when melted and
whilst being mixed, to be confined, or nearly so, from the air, by the furnace

page_text: to suit them according to directions given for the bridge damper. The prin-
cipal thing to attend to is, that all these dampers should be either quite shut
and fit close, or be quite open; the fire should have plenty of room to pass or
be turned altogether another way; if this is not done the dampers will be soon
destroyed. The additional flue to the chimney should lead from the extreme
back of the grate, and the distance should be farther through it from the grate
to the chimney than through the furnace to the chimney, the fire will not then
have a tendency to work through it, except when the other passage is
closed. This flue should be so confined as only to have draft enough
to take away the smoke from the fuel; too strong a draft will draw air
over the metal, through the mixing door, between the groove and the
bridge damper, and cause more loss of volatile metal; should the damper in
the additional flue become heated at the part where it touches the top of the
flue a small quantity of air may be admitted on the top of the iron frame at
each corner E, Figure 7, and E, Figure 8. The dampers in the bridge and
in the additional flue being moved and hung on the same lever must be
adjusted by lengthening or shortening the suspending rods, so that the one
lowered shall not touch the bottom of the groove or recess before the other
reaches near enough to the top to close the passage sufficiently. Care also
should be taken to have the lever correctly proportioned, so that either damper
may not be raised to its place without lowering the other out of the heat.
The red dotted lines, Figure 4, show the position of the bridge damper when
closed, the blue dotted lines show its position when open. Figures 3 and 7
shew sections of the interior of the furnace. G, the grate. F, the additional
flue direct to the chimney. E, groove or recess for damper. C, Figure 7,
chambers through which the rods work for raising the dampers. H, Figure 3
and Figure 7, the bridge. I, the bed or reverberatory. J, opening through the
bridge to keep it from getting too hot, but without any connection with the
interior of the furnace. The blue parts in the Drawing represent iron; the
yellow, fire bricks; and the red, common red brick.
I next describe the damper in the front flue, between the reverberatory and
the chimney. This damper is made of cast iron, as brick will not stand the
change from heat to cold, to which it is necessarily exposed; being made
of iron it should never be used, except when the fire is turned through the
back flue by means of the other dampers, and in all cases when used it must
be placed so as to cover the flue entirely; it consists merely of a plate of iron,
three quarters of an inch thick, on which are cast ribs to keep it from warping,
as shewn in Figures 8 and 9, made to a scale of one inch for each foot. For