AN IMPROVED METHOD OF CONSTRUCTING AND WORKING GAS FURNACES
Year: 1883

page_text: LETTERS PATENT to Frederick Siemens of N° 12 Queen Annes Gate
Westminster in the County of Middlesex for an Invention of "AN IMPROVED
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2
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PROVISIONAL SPECIFICATION left by the said Frederick Siemens at the
Office of the Commissioners of Patents on the 8th December 1883.
FREDERICK SIEMENS of N° 12 Queen Anne's Gate, Westminster in the County
of Middlesex, "AN IMPROVED METHOD OF CONSTRUCTING AND WORKING GAS
FURNACES"
In gas furnaces, as they are usually constructed and worked, the flame is
directed on and caused to strike the objects or materials that are to be heated.
This, by the chemical action of the substances in combustion, or by the mechanical
action of solid particles carried with the flame, often seriously damages the
materials acted on, and the crucibles, pots or other vessels containing them, as well
as the walls of the furnace itself. Moreover, when the flame impinges on objects
colder than itself or obstructing it, the combustion is rendered imperfect, and
consequently there is considerable waste of fuel.
My invention has for its object to avoid these evils by so constructing and
working furnaces that the flame is kept entirely clear from the objects or materials
that are to be heated, and as much as possible from the furnace walls, and that the
whole of the heat is obtained by radiation from the flame itself and from the roof
and walls of the furnace chamber, which are heated by radiation from it. Furnaces
operating in this manner may be of various forms. They may be chambers of
considerable length vaulted over, with the flame passing along their upper part
from end to end; or they may be of circular, semicircular, horse-shoe or other
equivalent form, such that the combustible gases enter by one opening, and sweep
round the chamber, and the products of combustion issue by an opening adjacent
to the inlet. The object in all cases is to get a considerable length of travel for a
flame of large volume moving slowly in a line, which keeps it as clear as possible
from the walls, roof and bed of the furnace chamber. The slow movement of the
Price Bdi

page_text: flame is of advantage as preventing the agitation of the dust or other fine particles,
and the injurious effects of these on the furnace walls and the materials acted on.
In furnaces such as those employed for glass having working doors over the tank
or melting pots, I provide that the flame shall move along at a level above these
doors, so as not to interfere with the operations carried on through them. And, in
like manner, I arrange steel melting, reheating and other furnaces, so that the
flame is kept above the working doors:
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frederick Siemens in the Patent Office on the 7th June 1884.
FREDERICK SIEMENS of N° 12 Queen Anne's Gato, Westminster, in the county
of Middlesex "AN IMPROVED METHOD OF CONSTRUCTING AND WORKING GAS
FURNACES"
In gas furnaces, as they are usually constructed and worked, the flame is directed
on and caused to strike the objects or materials that are to be heated. This, by
the chemical action of the substances in combustion, or by the mechanical action of
solid particles carried with the flame, often seriously damages the materials acted
on and the crucibles, pots or other. vessels containing them, as well as the walls of
the furnace itself. Moreover, when the flame impinges on objects colder than
itself or obstructing it, the combustion is rendered imperfect, and consequently
there is considerable waste of fuel.
My invention has for its object to avoid these evils by so constructing and
working furnaces that the flame is kept entirely clear from the objects or materials
that are to be heated, and as much as possible from the furnace walls, and that the
whole of the heat is obtained by radiation from the flame itself and from the roof
and walls of the furnace chamber. which are heated by radiation from it.
Furnaces operating in this manner may be of various forms. They may be
chambers of considerable length vaulted over; with the flame passing along their
upper part from end to end, or they may be of circular, semicircular, horseshoe or
other equivalent forms, such that the combustible gases enter by one opening, and
sweep round the chamber and the products of combustion issue by an opening
adjacent to the inlet.
The object in all cases is to get a considerable length of travel for a flame of
large volume moving slowly in a line which keeps it as clear as possible from the
walls, roof and bed of the furnace chamber. The slow movement of the flame is
of advantage as preventing the agitation of the dust or other fine particles and the
injurious effects of these on the furnace walls and the materials acted on.
In furnaces such as those employed for glass, having working doors over the
tank or melting pots, I provide that the flame shall move along at a level above
these doors, so as not to interfere with the operations carried on through them.
And in like manner, I arrange steel melting, reheating and other. furnaces, so that
the flame is kept above the working doors.

page_text: The accompanying drawings represent various constructions of furnaces as
examples shewing how my invention may be carried out in practice under various
conditions.
Fig. 1 is a longitudinal section of a furnace for melting glass in pots, fig. 2 is a
sectional plan on the line X X and fig. 3 is a transverse section on Y Y.
Fig. 4 is a longitudinal section of a crucible steel furnace, and figs 5 and 6 are
transverse sections on X X and Y Y respectively.
Fig. 7 is a longitudinal section and fig 8 a part sectional plan of a glass tank
furnace of horse-shoe form.
Figs. 9, 10 and 11 are respectively a longitudinal section, a transverse section
on X X and a sectional plan on Y Y of a horse shoe furnace for melting glass
in pots.
Fig. 12 is a longitudinal section, and fig. 13 a sectional plan of an open hearth
steel melting furnace of horse-shoe form.
Fig. 14 is a longitudinal section and fig. 15 is a sectional plan of an open hearth
steel melting furnace of rectangular form.
Fig. 16 is a longitudinal section of a reheating or annealing furnace.
In these figures R are the regenerators, & the gas flues and L the air flues
leading into the furnace chamber from the regenerators, and acting alternately for
supplying from the one set of regenerators, the heated gas and air to form the
furnace flame and to convey the hot products of combustion to the other set of
regenerators in the usual way. C is the roof of the furnace chamber, O are
working doors, or in the case of the crucible steel furnaces are removeable covers
for introducing or withdrawing the crucibles.
The gas and air ports instead of being arranged so that the flame can impinge
on the pots; crucibles or material in the tank or on the bed of the furnace, are at
such height that the flame shall pass clear of the objects to be heated, and when
these are pots or crucibles, or lumps of metal or other material they are placed
sufficiently far apart to allow free access of the radiated heat to all parts of them.
The gas and air ports also open at some distance below the roof of the furnace,
and at some distance from its side walls, so that the flame has unobstructed space
for its free development, and is kept as much as possible from contact with the
roof or walls. Also where the furnace has working doors, the flame should pass
above their level, so that the material operated on is subjected only to the radiant
heat of the flame without being brought in contact with it.
The gas and air passages may be arranged one behind the other, as in the
furnaces shewn in figs, 1, 2 and 3, and figs 9, 10, 11, also in figs. 12 and 13, or they
may be arranged side by side as in figs. 4, 5, 6 and 16; or both arrangements may
be used in one furnace as shewn in figs. 14 and 15, the air flue being behind the
gas flue at the one end, and air flues being one on each side of the gas flue at the
other end.
In the horse shoe tank furnace shewn at figs. 7 and 8, the air passages rise up
behind the gas passages, each pair being led horizontally with a certain amount of
convergence towards each other into the furnace chamber, near the ends of the back
wall thereof. The flame resulting from the combustion of the gas and air issuing
from the one pair of such passages, is caused by the draught to sweep round the
furnace chamber to the other pair of passages through which the products of
combustion pass into the other pair of regenerators. The gas and air passages are
made to meet together just before they open into the furnace chamber by one port
situated at some distance from the roof and side wall and at some height above the
glass in the tank; so that the flame of the gaseous mixture issuing from the port
burns without coming in contact with the roof or sides or with the glass in the
tank. The flame is also kept above the level of the working doors O.
The furnace for melting glass in pots, as shewn in figs. 9, 10 and 11 is of
construction similar to that of the tank furnace, as also is the furnace shewn by
figs. 12 and 13, except that in this case the space beneath the furnace is open, the
regenerators being placed in an excavation beyond the end wall of the furnace.
In

page_text: 'the furnace represented in figs. 14 and 15, the air and gas ports are at the one end
shewn arranged side by side, that is to say, a central port G for the gas with an air
port L on each side of it. .At the other end of the furnace, the air flue L is situated
behind the gas flue G and both bend over at the top, meeting in a single port
opening into the furnace chamber. The former arrangement of the air and gas
flués is used in the reheating or annealing furnace fig. 16.
It is to be clearly understood that in the various forms of furnaces above
described one main aimed at is to prevent contact of the actual flame with any
surface or object that is stationary or is colder than itself, as such contact interferes
with the completeness of the combustion and consequently reduces the heat
radiating power. When the flame ceases, the products of combustion though not
visible as flame, retain nevertheless a large amount of heat, and the combustion
having been completed when that condition is reached, these products are employed
to heat surfaces or objects by actual contact with them, whether they be the
bricks of a regenerator or the metal of a boiler or other objects.
Having thus described the nature of my invention and in what manner the same
is to be performed, I claim :-
Constructing and working a regenerative gas furnace in such a manner that the
'flame is made to move through it without contact with the objects or materials in
the furnace or with the roof or walls, and to act chiefly or entirely by radiation
substantially as and for the purposes herein set forth
In Witness whereof, I the said Frederick Siemens have hereunto set my hand
and seal this Twenty ninth day of May in the year of our Lord one thousand eight
hundred and eighty four.
FREDERICK SIEMENS (L.S.)