PROVEMENTS IN FURNACES
Year: 1861

page_text: LETTERS PATENT to Charles William Siemens and Frederick Siemens,
both of Great George Street, Westminster, for the lavention of
PROVEMENTS IN FURNACES."
Sealed the 19th July 1861, and dated the 22nd January 1861.
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
and Frederick Siemens at the Office of the Commissioners of Patents,
with their Petition, on the 22nd January 1861.
We, CHARLES WILLIAM SIEMENS and FREDERICK SIEMENS. both of Great
George Street, Westminster, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN FURNACES," to be as follows:-
These improvements relate to that class of furnaces where regenerators are
applied to receive the waste heat of the products of combustion, and to com-
municate the same subsequently to the air supporting combustion.
In constructing furnaces for melting glass or for other purposes where a
chamber is to be heated to a high degree, we place four regenerators below
the level of the bed of the furnaces, and when we place the regenerators
immediately underneath the furance we form a space for the circulation of
cold air between the arches covering the regenerator and the under side of the
bed of the furnace.
Passages lead from the upper extremity of two of these regenerators into

page_text: the furnace or chamber to be heated at one point or extremity. while similar
passages lead from the two remaining regenerators, and communicate with the
heated chamber at another point, the passages uniting upon entering or shortly
before entering the furnace. The lower extremities of the four regenerators
communicate with valves or reversing dampers, by means of which currents of
air and the combustible gas which we employ are directed through the whole
system of regenerators and furnace in the following manner: A current of
atmospheric air enters through one of the valves with one of the four rege-
nerators at the bottom, while a current of gas is directed into a second
regenerator. The two currents ascend through the masses of loosely piled
brickwork, or other refractory material of which the regenerators are composed,
and unite on entering the heated chamber or furnace where they are fired.
After having traversed the furnace the products of combustion pass downwards
through the two remaining regenerators, imparting heat to the same, and are
thence directed into a chimney. When the two last-named regenerators have
been beated sufliciently, the direction of the currents is reversed. Currents of
air and gas are made to enter these two regenerators separately, and are
heated in ascending through them and when these heated currents unite at
the point of entrance into the furnace they produce an intensely hot flame.
We arch over the regenerators in such a manner that the gases unite only
near the point where they enter the furnace, at which place they rise up
between perpendicular walls. These passages are so arranged that any fluid or
impurity that may fall from the furnace down them will not enter the rege-
nerator at all, but will be received by small chambers or pockets provided for
that purpose; proper openings or doors are provided by which these pockets
may be emptied from time to time as occasion may require.
It is an essential part of our Invention that the solid fuel should be
decomposed in a separate apparatus (which we shall hereafter describe). so
that the introduction of solid fuel into the furnace may be altogether avoided:
and independently of the advantage that results from heating the gaseous fuel
prior to its entering into combustion. there is a great advantage derived from
the absence of any solid carbon or ashes in the working chamber of the
furnace, by which we are enabled to carry on operations in the open furnace
which it has only been possible hitherto to conduct in covered vessels or pots.
We are thus enabled to melt fint and other superior qualities of glass in open
pots to fire pottery without enclosing the same in saggers. or to melt steel and
other substances upon an open hearth or bed without injury. Dampers are
provided in the cold air and gas channels, by which the quantity and quality
of the flame can be regulated to the utmost nicety.

page_text: advantageous to melt the materials composing the same in open pots, but to
cover them with moveable lids whilst working the metal out in the usual way.
When it is required to accomplish secondary operations in separate furnaces,
for instance, to heat annealing furnaces or lears in the manufacture of glass.
we accomplish this without providing separate regenerators, but by arranging
branch channels leading from the upper portion of the four regenerators to the
lear or furnace to be heated where they join in combustion. Dampers of fire
clay or other refractory material are provided to these channels to regulate the
flow of the gasses according to the direction in which the main furnace is
working. In firing pottery ware. in calcining ores, and other operations, it is
required that the furnace charged with these materials. after having been
heated to the desired degree, should cool gradually and completely before it is
charged again. In such cases we propose to provide two similar furnaces side
by side, and only one set of four regenerators, which by means of slides or
valves of fire-clay or other refractory material, can be made to communicate
at intervals with the one furnace or heated chamber or the other.
During the
time that one furnace is fired the other is allowed to cool, to be discharged
and charged again with fresh material, and vice versa. The regenerators are
thus always kept in working condition.
Another part of our improvements consists in the arrangement of the gas
generators. It is important that the combustible gasses produced from the fuel
should be as rich as possible in hydrogen, carburetted hydrogen, and carbonic
oxide, with as little admixture of carbonic acid, nitrogen, and incombustible
vapours as may be.
The apparatus should be so arranged as to be very regular in its action, and
be easily tended and freed from cinders from time to time. It is also import-
ant that the gas produced is not drawn through the furnace by the chimney.
but that the full atmospheric pressure is maintained in the channels leading
from the gas generator to the furnace, lest atmospheric air should be drawn in
through crevices and produce a partial combustion of the gas in the channels,
which might be accompanied by a deposition of carbon in the same.
The arrangements we adopt are as follows:-The fuel is fed through
openings fitted with lids or covers into a hopper, which we place by pre-
ference at a moderate inclination. From the hopper the fuel passes down an
inclined plane formed of brickwork at an angle of 45-degrees, or thereabouts,
and thence upon a grate, which may advantageously be inclined 30 degrees or
thereabouts to the horizon. Directly opposite the inclined plane and grate,
but at a sufficient height to allow of a thick layer of fuel on the bars, is a

page_text: brick arch parallel to it, or nearly so, which being once heated by the com-
bustion upon the grate radiates heat down upon the fresh fuel as it gradually
passes down the inclined plane, and thus causes its partial decomposition and
volatilisation, which is afterwards completed by the fresh air entering through
the grate.
The air in passing through the carbonaceous part of the fuel
produces in the first instance carbonic acid gas. accompanied by intense heat,
and then as this carbonic acid gas ascends through the mass of incandescent
carbon, it is converted into carbonic oxide of a somewhat lower temperature,
and this carbonic oxide, accompanied by its necessary proportion of nitrogen, is
directed by the arch over the surface of the fresh fuel upon the inclined plane,
and thus helps to volatilise the fuel. The combined gases are allowed to ascend
through a tube, which being exposed to the atmosphere causes the gases to
become somewhat cooled before they descend again to the valve by which they are
admitted to the regenerator; the preponderance of the cool descending column
over the ascending hot column of gas causes sufficient draught to produce a
plenum of pressure in the channels leading to the regenerator. If several
generators are provided we prefer to lead the gasses produced by them into a
main channel, which may be arranged to supply several furnaces, the advan-
tage of this arrangement being that a greater uniformity in quantity and quality
of the gas is obtained.
SPECIFICATION
in pursuance of the conditions of the Letters Patent, filed
by the said Charles William Siemens and Frederick Siemens in the
Great Seal Patent Office on the 22nd July 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we. CHARLES
WILLIAM SIEMENS and FREDERICK SIEMENS, both of Great George Street,
Westminster. send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters.
Patent, bearing date the Twenty-second day of January. in the year of our
Lord One thousand eight hundred and sixty-one. in the twenty-fourth year
of Her reign, did, for Herself. Her heirs and successors, give and grant unto us,
the said Charles William Siemens and Frederick Siemens, Her special licence
that we, the said Charles William Siemens and Frederick Siemens, our
executors, administrators, and assigns, or such others as we, the said Charles
William Siemens and Frederick Siemens, our 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

page_text: 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 FURNACES," upon the condition (amongst others) that we,
the said Charles William Siemens and Frederick Siemens, our executors or
administrators, by an instrument in writing under our or their hands and seals.
or under the hand and seal of one of us or them, should particularly describe
and ascertain the nature of the said invention, and in what manner the sanie
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 Charles William Siemens, on behalf
of myself and the said Frederick Siemens, 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: -
We are thus enabled
These improvements relate to that class of furnaces where regenerators are
applied to receive the waste heat of the products of combustion, and to
It is
communicate the same subsequently to the air supporting combustion.
an essential part of our Invention that the solid fuel used, such as coal, lignite.
peat. &c., should be decomposed in a separate apparatus, so that the introduc-
tion of solid fuel into the furnace may be altogether avoided, and the gaseous
fuel may be heated to a high degree prior to its entering into combustion with
atmospheric air, also heated to a high degree, thus causing a great economy
of fuel. There is also a great advantage derived from the absence of any solid
carbon or ashes in the working chamber of the furnace, by which we are
enabled to carry on operations in the open furnace. which it has only been
possible hitherto to conduct in covered vessels or pots.
to melt flint, extra white, and other superior qualities of glass in open pots,
to fire pottery without enclosing the same in saggers, or to melt steel and other
substances upon an open hearth or bed without injury. It is also important
in many operations that the state of pressure of the gases in the furnace should
be under entire control, and should sometimes exceed, and at other times
exactly balance, that of the atmosphere, in order to prevent the egress of flame
from, or the ingress of atmospheric air into the furnace on opening apertures
for the approach of the workmen attending the operation to be carried on, such
as blowing glass, puddling iron, &c. For this purpose we arrange four regene-
rators below the bed of the furnace, two of which serve to communicate heat
separately to the combustible gases and atmospheric air on their way to the
furnace, and the remaining two to absorb the waste heat from the products of

page_text: combustion passing through them indiscriminately before reaching the chimney
(their respective action being reversed at intervals), the currents of heated gas
and air in ascending through and from the regenerators into the furnace
causing a plenum of pressure within the same, which is capable of being
modified or regulated by valves for. the admission of the gas and air to the
regenerators and by the chimney damper. By the same arrangements the
chemical qualities as well as the intensity of the flame can be regulated to the
utmost nicety. In some cases where no great heat is required, or where the
gas used is very rich in combustible matter, the two regenerators intended for
heating the combustible gases may be suppressed and mere passages be substi-
tuted, but we generally prefer the four-regenerator arrangement.
prevent an accumulation of excessive heat in the arch covering the regene-
rators, and forming at the same time the support of the furnace bed, we
provide chambers between the same for the circulation of atmospheric air.
Glass, slag, or other matters that may flow from the bed of the furnace are
made to drop into pockets or chambers on the side of the regenerators, whence
they can be readily removed.
In order to
In applying our improvements to glass furnaces we find it sometimes advan-
tageous to melt the materials composing the same in open pots, but to cover
them with moveable lids whilst working the metal out in the usual way.
When it is required to accomplish secondary operations in separate furnaces.
for instance, to heat annealing furnaces or lears in the manufacture of glass,
we accomplish this without providing separate regenerators. but by arranging
branch channels leading from the upper portion of the four regenerators to the
lear or furnace to be heated, where they join in combustion. Dampers of fire
clay or other refractory material are provided in that case to these channels to
regulate the flow of the gases according to the direction in which the main
furnace is working; or we draw off the mixed gases in a state of combustion
from the prinicipal furnace. In firing pottery ware, in calcining ores, and other
operations, it is required that the furnace charged with these materials, after
having been heated to the desired degree, should cool gradually and completely
before it is charged again. In such cases we propose to provide similar
furnaces side by side and only one set of four regenerators, which, by means of
slides or valves of fire clay or other refractory material, can be made to com
municate at intervals with the one furnace or heated chamber or the other
During the time that one furnace is fired the other is allowed to cool, to bo
discharged and charged again with fresh material, and vice versa.
The
regenerators are thus always kept in working condition. Or we arrange fou
or more chambers in such a way that they themselves are made to, contain the

page_text: materials to be fired, serving alternately as regenerators and as kilns. to be
fired or discharged.
Another part of our improvements consists in the particular arrangements
of gas generators.
It is important that the combustible gases produced from
the fuel should be as rich as possible in hydrogen, carburretted hydrogen, and
carbonic oxide, with as little admixture of carbonic acid. nitrogen, and incom-
bustible vapours as may be. The apparatus should be so arranged as to be
very regular in its action, and be easily tended and freed from cinders from
time to time. It is also important that the gas produced is not drawn through
the furnace by the chimney, but that the full atmospheric pressure is main-
tained in the channels leading from the gas generator to the furnace. lest
atmospheric air should be drawn in through crevices, and produce a partial
combustion of the gas in the channels. which might be accompanied by a
deposition of carbon in the same. This, we accomplish in allowing the hot
gases to ascend from the generators and to descend again after they have been
partially cooled by exposure of the pipes containing them to the atmosphere.
The decomposition of carbon is. moreover, avoided by the introduction into the
generators or channels leading from the same, of streamlets of water or of steam,
which. in combining with the heated portion of solid carbon, form permanent
combustible gases with the same, namely. carbonic oxide and hydrogen. If
several generators are provided we prefer to lead the gases produced by them
into a main channel. which may be arranged to supply several furnaces, the
advantage of this arrangement being that a greater uniformity in quantity
and quality of the gas is obtained.
But in order that our Invention may be more easily understood and readily
carried into effect, we will now describe the best means we are acquainted with
of performing the same, reference being had to the accompanying Drawings.
Figures 1. 2. 3, 4, and 5. on Sheet 1., represent one arrangement of our
improved regenerative gas furnace as applied to the manufacture of glass,
together with the generator for the combustible gases employed therein,
Figure is a longitudinal section through the furnace and regenerators;
Figure 2 is a sectional plan: Figure 3 is a transverse section through the
furnace, regenerators. and gas generators: Figure 4 is a section through the
passages leading from the regenerators to the gas generators. chimney, and
atmosphere, and also shews the furnace in elevation; Figure 5 shews a longi-
tudinal section through one of the gas generators.
similar parts in all the Figures.
Similar letters indicate
A is the furnace, upon the bed a of which stand the glass pots X, X. X,
apertures b, b, b, being provided for working out the glass. Beneath the bed

page_text: of the furnace are the four regenerators B'. B. B. B. each consisting of a
chamber built of fire-brick, near the bottom of which is a grating c. c, c³, c';
upon this grating are piled the fire-bricks or other refractory material d', &,
d', d', in such a manner as to leave small interstices between each brick.
These regenerators are arched over at the top, and support the bed a of the
furnace. This consists of a number of slabs of fire-clay or other refractory
inaterial, having on their under side small channels e. e. e, communicating at
one end through the channel with the atmosphere, and at the other end with
the air passage I, conducting to the regenerators. A current of cold air is
continually passing through these channels, tending to maintain the bed of the
furnace, and the arches covering the regenerators. at a low temperature.
Communications are established between the top of the four regenerators
B', B2, B3, B. and the furnace A in the following manner:-The regene-
rator B' communicates with the furnace at the point C, through the passages
D', D', D', while the regenerator B2 communicates with the furnace at the
same point C, through the passages D. D. In a similar manner the rege-
nerator B3 communicates at the point C¹ with the furnace through the pas-
sages D3, D3, whilst the regenerator B' communicates with the furnace at the
same point C through the passages D', D'. D'. At these points C and C
the passages D' and D as also those D and D' are separated from each
other by the vertical division walls i, i', till they reach the level of the bed of
the furnace. It will be seen that any glass or other materials falling through
the apertures D1, D2, D3, D. from the bed of the furnace will not enter the
regenerators. but will fall into the chambers or pockets E. E', at the side of
the same, whence they can be removed through the apertures 1. 1', ordinarly
kept closed.
Each of the regenerators B'. B. B³. B'. are provided below the gratings
c, c, c, c, with openings F. F. F. F' by means of these the regenerators B'
and B communicate alternately with the passage G leading from the gas gene-
rators which will be hereafter described, and with the passage H leading to
the chimney, whilst the regenerators B and B communicate alternately with
the passage I, communicating with the atmosphere. and the passage H leading
to the chimney. These alternate communications are regulated by the reversing
valves or dampers g and in the following manner: If the valve g is in
the position indicated in Figure 4. then combustible gas from the generator
will pass through the passages J. J, and will enter the regenerator B' through
the aperture F: if at the same time the valve h is in the same position as g
then atmospheric air will enter from the passage into the regenerator B,
through the passage L and aperture F". If the regenerators B3 and B' have

page_text: been previously heated by the hot products of combustion passing through
them, then the currents of air and combustible gas in passing up through the
small interstices between the bricks will become heated to a considerable
degree. Arrived at the top of the regenerators they will be conducted through
the passages D and D to the point C' of the furnace, where on rising up
between the vertical division walls i. . they will unite, and on being ignited
evolve an intensely hot flame, which passes across the furnace and imparts its
heat to the glass pots X. X. X. Arrived at the other end of the furnace
the hot products of this combustion pass downwards through the passages D'
and D. into the regenerators B' and B: here on passing downwards through
the mass of loosely piled bricks. these latter absorb the greater part of the
heat of the gases. and they issue in a comparatively cold state through the
apertures F and F into the passages K. K. and M. whence the reversing
valves gandh being in the position indicated, they are conducted through the
flue II. H. to the chimney shaft. When by the continued passage of the hot
products of combustion the regenerators B and B have become heated to a
considerable degree the position of the valves or dampers g and h are reversed
by means of the levers Z. Z; combustible gas will now enter into the rege-
nerator B', and atmospheric air into the regenerator B; these currents of gas
and air on passing up through the regenerators will become heated to a con-
siderable degree. and on emerging from them at the point C will mix, will
become ignited, and the hot products of combustion after traversing across the
furnace will pass down at C¹ through the regenerators B and B'. imparting
to these the greater part of their heat, and thus each pair of regenerators will
alternately serve to absorb the heat from the products of combustion, and then
give off this same heat again to the gas and air serving to produce this com-
bustion. A passage Y is provided at the side of the regenerators for obtaining
access to them through the openings ',, ', v.
The combustible gases are produced in a series of gas generators N, N, by
the imperfect combustion of fuel. In these gas generators the fuel is intro-
duced through the hoppers O, kept closed by means of the covers o. o; from
these hoppers the fuel descends on to an inclined plane P of fire-brick or other
refractory material, which may be inclined about 45 degrees; thence the fuel
passes on to the fire-grate Q, which should be inclined about 30 degrees.
Over this grate, but at a sufficient height from the same to allow a deep layer
of fuel to intervene is an arch of fire-brick R. This arch being once heated
to a considerable degree by the fire on the grate radiates heat on to the fresh
combustibles as they pass down the inclined plane P, and thus causes their
partial decomposition and volatilization, which is afterwards completed by the

page_text: atmospheric air which enters through the grate Q.
This air on passing
through the layer of highly heated fuel lying upon the grate is first decom-
posed into carbonic acid gas with a certain proportion of nitrogen, and after
wards on passing up through the thick layer of fuel in a less state of incan-
descence. it becomes transformed into carbonic oxide, and in this form passes
over the surface of the fresh fuel on the inclined plane P. where it mixes with
the gases evolved from the same, and then passes up through the passage S
into the vertical pipe T. and from this into the horizontal pipe I, which
establishes a communication between all the gas generators and the regene-
rators B and B*. This pipe descends again at 1, where it joins on to the
flue G. by which means the column of gas in the pipe U being somewhat
cooler, and consequently more dense than the column of gas in the pipe S, a
sufficient draft is maintained without the gases in the flue G having to he
drawn through by the action of the chimney, and thus a plenum of pressure
is maintained in these passages so as effecinally to prevent atmospheric air
entering into them through fissures, and causing a partial combustion of the
gases.
An aperture V is formed in the top of the generator for the purpose of
stirring the fuel from time to time. Valves ir are provided in the pipes T of
each gas generator so as to shut off the communication with any one of them
when not in use or under repair. A small water supply pipe k is provided with
little branches and taps for admitting a small driblet of water into the gas
generator through the funnel on the pipe T: this small current of water
passing along the side of the pipe, and falling partially on the body of the
fuel, becomes vapourized, and the vapour thus formed acting upon any hot
particles of carbon rising up with the gases combines with the same, forming
two combustible gases, namely carbonic oxide and hydrogen.
In
The gas generator just described is particularly adapted for dry coal.
Figures 6 and 7 is shewn an arrangement of the same which we prefer
employing where very gaseous or "baking" coal is used. The general con-
struction is in most respects similar to the just described one. A. A, are
hoppers through which the fuel is introduced: B. B. are the inclined planes
of fire-brick over which the fuel passes, whence it falls on to the table C. In
place of the ordinary fire-grates we here employ two iron plates D. D, with
perforations, and provide two bats E. E. beneath these with apertures for the
means of breaking up the coal when it becomes caked.
Apertures F, F. are
The heated arch G
also provided for stirring up the coal from the top.
serves to volatilize the fresh fuel partially as it descends from the hoppers:
His the ascending flue through which the gases are conducted to the rege-

page_text: nerators. Streamlets of water may be introduced through 11, or elsewhere,
which are not shewn on the Drawing. The passage H is sometimes con-
tinued down into the body of the fuel, as shewn in dotted lines, so that the
combustible gas has to pass through the fuel before entering the same, and is
thus deprived of particles of tar. &c.
Figures 8 and 9 shew an arrangement of our improved regenerative gas
furnace as applied to the manufacture of glass, where the furnace is of a
circular shape. and is also connected with a lear for annealing purposes.
Figure 8 shews a sectional elevation of the furnace and lear, and Figure 9
shews a sectional plan of the furnace and regenerators. The furnace A itself
is here of an annular shape: the central space B communicates by means of
the apertures a. a. with the furnace, and is provided at the top with a flue b,
through which it communicates with the lear C. constructed immediately over
the furnace. This is closed at either end by doors, or in any other temporary
manner, and is provided at one end with the chimney shaft D. having a
damper c. Beneath the bed of the furnace, which is provided with channels
e, e, for the circulation of cold air. are the four regenerators E'. E. E', E',
constructed in a similar manner to those described with reference to Figures I,
2, 3, and 4. These communicate with the furnace at F, F. through the
passages G'. G, G. G. and are connected below with the passages from the
gas generators. the atmosphere. and the chimney, which are not shewn on
the Drawing. Reversing valves or dampers, also omitted on the Drawing,
cause the combustible gas and air to flow through one pair of regenerators,
and then cause the products of their combustion, after traversing the furnace
A, and heating the glass pots X. X. X, to pass down through the other pair
of regenerators in a precisely similar manner to the regenerators described in
Figures 1, 2, 3, and 4.
When it is required to anneal objects of glass in the lear C whilst the
furnace is at work. the damper in the chimney D is opened, in consequence
of which a portion of the gases in a state of combustion pass from the fur-
nace A into the chamber B. and thence through the flue into the lear C,
where they heat the objects placed in the trays d, d, d, to the required extent
in that portion of the lear immediately over the furnace, and then escape up
the chimney D. The trays d, d, containing the articles, in being passed
gradually along towards the chimney, are removed gradually from the hotter
to the cooler portion of the lear, as is well understood. When the lear is
not in operation the damper c in the chimney D is closed, and the hot products
of combustion are thus prevented from escaping from the furnace into the
lear

page_text: In our improved regenerative gas furnaces for glass we sometimes dispense
with the use of pots altogether, and place the materials to be melted on the
bed of the furnace itself, which is then made of a certain depth.
In Figure 10, Sheet II., of the accompanying Drawings is shewn such an
arrangement. The bed of the furnace A consists of the two sloping sides B, B,
and the central channel C. Upon the highest part of the sloping sides B. B,
are heaped the materials a, a, to be melted. The heated currents of com-
busible gas and air passing into the furnace from the regenerators D. through
the passages E in a similar manner to that already described with reference to
Figures 1. 2. 3. and 4, on Sheet I., are ignited in the furnace, and the intense
heat thus produced melts the heaped-up materials a. a, and the melted glass
running down in a thin sheet from these heaps over the highly heated
surfaces B, B. of the bed planes at once, and is in this state collected in the
channel C. whence it may be worked out. immediately, instead of having to wait
several hours before the glass planes, as is the case where it is melted in pots.
The hot products of combustion pass down through the passages E' into the
other pair of regenerators D', in the same manner as has already been described.
Channels e, e, f, J. are formed in the bed of the furnace, through which cold
air circulates to moderate the temperature of the same. This arrangement of
furnace may also be employed with advantage for smelting iron, for making
steel, or roasting copper and other ores.
In Figures 11, 12, and 13 is shewn a construction of our improved regene-
rative gas furnace adapted for the purpose of puddling iron.
Figure 11 shews a longitudinal section through the same; Figure 12 shews
a sectional plan above the bed of the furnace; and Figure 13 shews a sectional
plan of the regenerators.
The bed A of the furnace B is made of a considerable depth, and is con-
structed of iron covered with fire-brick or other refractory material. Below
the bed, spaces a. a. a, are provided for the circulation of cold air. Beneath
the furnace are the regenerators C, C C C constructed in a similar manner
to those already described. By means of the reversing valves or dampers
D, E, actuated by the levers d, e, the regenerators C and C are made to
F
communicate alternately with the gas generators through the passages
and G, and with the flue Z leading to the chimney, whilst the regenerators C
and are made to communicate alternately with the atmosphere through the
passages H and I, and with the chimney through the flue Z. Thus if gas is
entering at the bottom of the regenerator C, and atmospheric air is entering
at the bottom of the regenerator C', they become heated on passing through
the masses of loosely piled bricks arrived at the top they pass up through the

page_text: passages J and K. and into the furnace through the side openings J'. K';
here they unite, and on being ignited heat- the furnace to the required extent,
the hot products of combustion traversing across the furnace and then passing
through the side openings L'. M'. into the passages L. M. and then down into
the two regenerators C' and C. in the manner as already herein-before described
with reference to other arrangements. The apertures J. K. L. and M'.
leading from the regenerators into the furnace are here with advantage con-
structed in the side of the same instead of in the bed, as in the before-described
arrangements. This allows of channels N and O being formed between them,
leading from the bridges b. b. down to the small openings c, c, through which
cinders and other impurities are removed from the furnace. A door X is pro-
vided as usual in the side of the furnace for working the iron.
In Figures 14. 15. 16, and 17. on Sheet 1.. is shewn the application of
the principle of our regenerative gas furnace to the burning of bricks or other
objects in kilns: Figure 14 shews a longitudinal section through four such kilns
in connection Figure 15 shews a sectional plan of the same, as also a plan of
the gas generator connected thereto; Figure 16 shews a transverse section: and
Figure 17 shews a section through the gas generator.
In this arrangement the bricks or other objects to be burnt or fired are piled
up loosely in the kilns, and themselves form the regenerators, which alternately
absorb the heat from the products of combustion resulting from the burning
of gas and air in one of the charged kilns, and then after being themselves
fired give off their heat again to the air serving for the combustion of gases
in another kiln.
The four kilns A', A, A. A are for this purpose connected with each other,
with the gas generator. with the chimney, and with the atmosphere in the
following manner: The bottom of the kiln A' communicates with the top of
the kiln A through the passage a', the bottom of A communicates with the top
of A" through the passage d, the bottom of A communicates with the top of A',
through the passage . and the bottom of A' communicates with the top of A'
through the passages X and a'. Slides c', c, c, c, for dampers are provided
in each of the passages a'. . a, a, but there is only one damper to all the
four passages. which is consecutively placed in each, as shall be hereafter
explained. An underground flue B passes from the gas generator C, which is
also below the level of the ground along the front of all four kilns, in front of
each of which it opens into the vertical shafts D1, D2, D3, D', which are closed
at the top, and from which branch the pipes E, E, E, E',; these pipes enter
into the centre of the side of each kiln, and branches e', e, e, e', on the same
also enter into the before-mentioned passages a, a, a, a.
All these branches

page_text: are provided with valves actuated by the levers b'. . . b, by means of which
the gas can either be admitted through the passages a'. a. a', a', into the top of
the kiln or through the branches E E E E into the middle of the kiln, or
the gas can be shut off from the kilus altogether. When the kilns are charged
with bricks or other objects to be burnt a tube F. F. F. F'. having per-
forations is placed in the same in such a position that the gas when entering
the kiln through the pipes E'. E. E. E' passes into these tubes, thus being
more equally distributed throughout the mass; or in place of having tubes
such passages may be formed with the bricks themselves. Rows of bricks are
left out here and there at the level of these tubes so as to allow of the easy
egress of the gas from them. Each of the kilns is furthermore provided
with an aperture G. G. G. G. at the bottom, connecting them by means of
branches to the flue 11 conducting to the chimney shaft: each of the openings
are capable of being closed by means of dampers g. 9. g. 9*.
Large openings 1, 1. 1. 1. are provided at the top of each kiln for the
purpose of charging and discharging them; these are temporarily bricked up
when the kiln is at work, but the one being open where the kiln is being
charged serves to admit the atmospheric air that has to assist the combustion
of the gas in the kiln that is being fired. If we now suppose that the contents
of the kiln A are being fired. that the contents of the kiln A have been
freshly filled in, and are being heated preparatory to firing that the kiln A³
is being discharged and charged afresh, and that the kiln A has just been
fired and is now cooling. then the action of the four kilns will take place as
follows: All the passages from the gas generator to the kilns will be closed
excepting the one at e': the damper will be placed in the passage a shutting
off the communication between the kiln A2 and 3: all the communications
with the flue H leading to the chimney will be closed with the exception of
G. Combustible gas will now enter at the top of the kiln A' through the
passage at the same time atmospheric air will enter through the open
kiln A. will pass through the hot contents of the kiln A. and become con-
siderably heated: it will then pass through the passage X to the kiln A',
where it will mix with the combustible gases; these will then be ignited and
produce considerable heat by which the contents of the kiln will be burnt.
The hot products of this combustion will then pass down to the bottom of the
kiln, and thence through the passage to the top of the kiln ; they will
then pass downwards through the contents of this kiln. which will absorb the
greater part of the heat from these gases, which will eventually escape through
the opening G into the flue Il conducting to the chimney. After a time the
valve in the branch e¹ will be closed and that in E opened, so that the com-

page_text: bustible gases will pass in to the middle of the bricks and be there ignited, so
as to burn the bricks equally throughout. When this has been completed.
and the bricks in the kiln A have become heated io a considerable degree the
valve at E is closed, whilst that at eis opened. The kiln A3 having in the
meantime been charged and the openings 13 closed up. the damper is removed
from the passage a² to the passage . shutting off the communication between
the kilns A and A. The contents of this latter having become cooled it is
opened and discharged: cold air enters through it, passes through the pas-
sage into the kiln A' where it becomes heated by passing down between
the hot bricks and then enters the kiln A which is to be fired.
The open-
ing G from the kiln A into the flue I having been closed, and the one G³ in
the kiln A opened. the hot products of the combustion taking place in the
kiln A² pass hence down through the kiln A³ freshly piled with materials
which absorb the greater part of their heat. and thus cooled they escape
through the opening G into the flue H. In this manner it will be seen that
cach kiln is in rotation charged with bricks or other objects to be burnt. is
then made to absorb the heat from the products of combustion, is fired, is then
cooled by the passage of atmospheric air serving to support combustion in
another kiln. and is lastly discharged and charged afresh. To allow of the
perfect circulation of the hot gases and air at the bottom of the kilns they are
there provided with a series of dwarf walls f. f. f. having spaces between
them, upon which walls the bricks or other objects are piled. The hot
products of combustion always passing through the bricks in a downward
direction thereby burn them much more uniformly than if the currents passed
in an upward direction, as in the latter case partial currents are liable to be
formed acting in a partial manner on the bricks. These kilns may also be
charged with earthenware instead of bricks, or they may be filled with saggers
containing porcelain. Instead of being placed in a row they may also be
arranged in a circle, and instead of only employing four compartments any
number may be added to the system.
The gas generator C is precisely similar in construction to those described
with reference to Figures 1, 2, 3. 4. and 5, on Sheet I., with the exception
that the generator being here below the level of the kilns the vertical pipe
for taking off the gases is here dispensed with, as the gases pass at once
through the opening d into the passage B. whence they rise up and pass into
the kilns, as already described. A streamlet of water may here also be intro-
duced into the generator for the purpose as herein-before described.
In Figure 18 is shewn an arrangement in which our improved regenerative
gas furnace is employed for the purpose of heating retorts, either for the

page_text: manufacture of gas or for any other process, which has to be carried on in
retorts, such as zinc retorts, muffles, &c.
A is the furnace, in which may be fixed any number of retoris B, B. B;
C, C, are the regenerators, for heating the combustible gases, and air which
undergo combustion in the furnace, and for taking up the heat resulting from
this combustion, in the manner already described with reference to other
arrangements.
Having now described the nature of our Invention, and the best modes we
are acquainted with of performing the same, we wish it to be understood that
we do not confine ourselves to the precise details shewn on the accompanying
Drawings; but we claim as our Invention the various arrangements of rege-
nerative furnacés worked by the gases resulting from an imperfect combustion
of solid fuel in separate places, as herein-before set forth.
In witness whereof, I, the said Charles William Siemens, have hereunto
set my hand and seal, this Nineteenth day of July, in the year of our
Lord One thousand eight hundred and sixty-one.
C. W. SIEMENS. (..s.)