IMPROVEMENTS IN THE APPLICATION OF GAS FURNACES TO EVAPORATING, SMELTING, PUDDLING. AND OTHER MANUFACTURING PURPOSES
Year: 1868

page_text: LETTERS PATENT to Charles William Siemens, of No. 3, Great George
Street, Westminster, in the County of Middlesex, for the Invention
of "IMPROVEMENTS IN THE APPLICATION OF GAS FURNACES TO EVAPORATING,
SMELTING, PUDDLING. AND OTHER MANUFACTURING PURPOSES."
Sealed the 2nd October 1868, and dated the 7th April 1868.
PROVISIONAL SPECIFICATION left by the suid Charles
William
Siemens at the Office of the Commissioners of Patents, with his
Petition, on the 7th April 1868.
I, CHARLES WILLIAM SIEMENS, of No. 3. Great George Street, West-
minster, in the County of Middlesex, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE APPLICATION OF GAS FURNACES
TO EVAPORATING, SMELTING. PUDDLING, AND OTHER MANUFACTURING PURPOSES," to
be as follows:-
In applying regenerative gas furnaces, as described in the Specification
to certain Letters Patent granted to me and Frederick Siemens, dated
22 January 1861, No. 167, to certain chemical and metallurgical opera-
tions, such as the calcining and smelting of copper, lead, and other ores,
it is requisite to arrange the regenerators in a more accessible manner
[Price 8d.]

page_text: than that described in the Specification to the said Patent in order to
clear them from the dust and ashes passing in with the hot gaseous
products of combustion. For this purpose, instead of constructing the
regenerators in a vertical position and closely side by side, as was
generally done heretofore, extending to a considerable depth below the
furnace, I arrange them horizontally, extending partially beneath the
furnace and partially beyond the same, the two regenerators of each pair
Deing placed one above the other, by preference the gas regenerator
uppermost, and the two pairs being so arranged with passages between
them, or at the sides or ends thereof, as to be accessible for clearing
them of deposits when required. The walls of the regenerators are for
this purpose provided with closed side apertures for the introduction
of clearing tools, and closed apertures are also provided in the roof of
the furnace over the vertical passages leading from the regenerators
into the furnace in order to gain access to these for clearing them of
deposits. This horizontal arrangement of regenerators has the further
advantage of requiring but little depth below the ground line of the
furnace, whereby the construction thereof is facilitated. Each pair of
regenerators may be made to communicate with opposite ends of the
furnace, as in the arrangements employed heretofore, but in cases where
it is desirable to make the furnace bed accessible from three sides, as in
copper and lead smelting furnaces, and also in puddling furnaces, I
arrange both pairs of regenerators to communicate with one and the
same end or side of the furnace. For this purpose the ascending gas
and air passages to each pair are made to unite in a small mixing
chamber just before entering the furnace, in which chamber the mixing
and ignition of the gases takes place, whereby, owing to the confined
space of such chamber preventing the expansion of the gases therein,
these are thrown in a jet through a tapering aperture in the chamber
into the furnace, so as to pass right to the end or across the bed, and in
returning to escape through the aperture conducting to the other pair
of regenerators. The reversing valves to the gas and air passages may
either be arranged as heretofore, or in place of their being made to turn
on a horizontal axis from one position into another, the valve casing may
be made cylindrical and the valves be so formed and connected to a
vertical spindle actuating them as to revolve from one position into the
other with the vertical spindle. The two valves being conveniently
placed one above the other with the chimney flue between them, they
may both be actuated by one and the same spindle passing through from

page_text: the one valve casing to the other, whereby only one operation is needed
for reversing the two valves. In some furnaces, such as for puddling,
heating, and making steel on the open hearth, I prefer to admit the
heated combustible gas into the furnace at the level of the bridge and to
conduct the air up through passages to within a short distance of the
arch, so as to throw it into the furnace at a higher level than the gas,
and thus to protect the arch from the more intense heat and the metal
from the oxydizing action of the air. The combustion of the gas and
air is also by this means facilitated, as the gas by its lighter specific
gravity tends to rise up through the air above it, and thus an intimate
mixture of the two is effected.
on the
In constructing such gas furnaces for the manufacture of glass
open bed, I construct the bottom of the bed of a slab of iron on which
the glass forms its own bed, and I construct the sides of the bed of a
series of hollow iron boxes through which cold water is made to circulate
by means of pipes connecting the separate boxes, and so arranged that
they conduct the water from the top of one box into the bottom of the
next one.
In applying regenerative gas furnaces to the manufacture of soda,
I firstly arrange the salt cake furnace consisting of the roasting hearth
and evaporating pan with a set of horizontal regenerators beneath the
former, the regenerators being, however, so arranged that a certain
quantity of heated gas and air is made to pass from them beneath the
evaporating pan and to heat the same by their combustion, the other
portion of the gas and air being conducted into the roasting hearth
through passages at opposite sides thereof. The roasting hearth and
evaporating pan are made to communicate with each other through an
aperture closed with a fire-clay plug, which is withdrawn when it is
desired to introduce the materials from the evaporating pan into the
roasting hearth. For the conversion of the salt cake, I introduce the
same, together with the requisite amount of lime and carbonaceous
matter, into a vertical revolving drum of known construction, having
two opposite central side openings, through one of which 1 cause to pass
combustible gas and heated air entering through separate passages,
which gas and air enter into combustion in the drum as this revolves
and heat the materials contained therein; or a furnace with solid hearth
of the usual form may be employed in place of the revolving. drum. The
hot gaseous products of combustion then pass through the opposite sidę

page_text: opening in the drum or furnace into a chamber containing a series of
pipes through which the air required for effecting the combustion in the
drum or furnace is caused to pass, and thus becomes heated to the
requisite degree. The gases in entering this chamber are made to descend
and to re-ascend, thus being made to deposit their dust before entering
the evaporating chamber containing alkaline liquid, whence, after having
taken up vapour from the surface of the liquid, the gases escape into
the chimney. For the finishing furnace I arrange a set of horizontal
regenerators beneath a bed of considerable length, the hot gas and air
being made to pass into the furnace alternately at either end by the
usual arrangement of reversing dampers, while the
bustion escape at the opposite end. Near each end of the furnace
openings are formed through the roof through which the drained soda
ash is introduced on to the bed in such a manner that the fresh charge
is always introduced at that end of the bed at which the products of
combustion escape, so as to be first acted upon by the lower heat of such
gases before being subjected to the intense heat produced at that end
when the action of the furnace is reversed.
products of com-
In applying regenerative gas furnaces to the burning and enamelling
of pottery and china, and to other similar processes which require gradual
heating and cooling, I arrange a series of two or more ovens, kilns, or
muffles over and in communication with one and the same set of two
pairs of regenerators, so that when one or more of the ovens, kilns, or
mufles are cut off from the regenerators these shall be usefully employed
in heating one or more other ovens, kilns, or muffles.
For this purpose
each pair of gas and air regenerators communicates through openings
provided with dampers with transverse passages situated beneath cach
of the kilns, whence the gas and air after mixing pass either directly
into the kiln and enter into combustion there or the combustion takes
place in the passages only, and the hot gases are made to pass through
flues surrounding the kiln, oven, or mulle so as to heat the goods
contained therein without coming in contact therewith; or the com-
bustion may take place in those kilns in which processes are carried on
that are not injured by immediate contact with the gases, and a portion
of the hot products of combustion may then be made to pass from such
kilns through flues surrounding other kilns, ovens, or muffles situated
by preference above those first named, and in which the more delicate
processes are carried on, the passage of the gases through such flues and

page_text: consequently the heat imparted to the upper kilns being regulated by
means of dampers closing apertures through which the thues communicate:
either with the atmosphere or with a chimney.
In calcining ores and other metallurgical operations the employment
To obtain
of currents of highly-heated air are sometimes desirable.
such heated currents I erect a pair of vertical regenerators with ascending
gas passages between the two, and I direct a current of atmospheric air.
alternately through the one or other regenerator in an upward direction,
which on meeting the gas at the upper extremity of the regenerators
causes a flame, which, in descending through the second regenerator in-
parts heat to the same preparatory to such heat being communicated to
the ascending current of atmospheric air. At or near the upper extremity
of each regenerator is an orifice, capable of being opened or closed by a
valve or brick slide so as to communicate at will with a passage leading
to the calciner or other apparatus where highly-heated air is required.
The air passing upwards through one of the regenerators being more
than suflicient to support the combustion of the gas, is made to pass in
greater part to the calciner without entering into combustion. In reversing
the direction of the ingoing current to the regenerators the orifices for
the hot air currents are at the same time changed from one regenerator
to the other, and a continuous current of highly-heated air is thus
produced.
-
In applying gas furnaces to the heating of steam and other boilers
I conduct the combustible gas from the gas producers through tapering
jets into the one end of the flues of the boiler, such jets being made to
pass through passages in front of the flues through which the air required
for the combustion is made to pass, entering the Ines through annular
orifices surrounding the gas jets. The perfect. combustion of the gas and
air is further facilitated by the introduction of rings of fire-clay into the
boiler flues at a short distance in front of the gas jets, and which become
highly heated by the impinging of the flames upon them. The flames
and products of combustion, after traversing the internal and side flues
of the boiler, are caused to impart the greater portion of their remaining
heat to a series of pipes through which the air required for the coni-
bustion is caused to pass; and the gases afterwards escape into the
chimney with only such an amount of heat as is requisite for producing
the necessary draught. A central tube passes from the outside through
the gas-jets for introducing a light for igniting the mixture of air and gas

page_text: in the first instance, through which tube also, if requisite, atmospheric
air may be made to enter into the centre of the gas jet to effect its more
complete combustion, on the same principle as the Argand burner. The
quantity of gas and air passing into the flues is regulated by means of
valves or dampers, so as to maintain any desired degree of heat. This
arrangement may with advantage be applied to marine boilers, in which
case the requisite gas producers are erected in a separate portion of the
vessel, a large collecting gas tube or tubes conducting the gas from
the producers to the front of the boilers with a branch furnished with a
regulating valve descending to each fire-place. The tubular arrangement
for heating the incoming air may be conveniently placed at the base
of the chimney stack. The advantages of this arrangement are, the
entire absence of smoke from the chimney and the greater evaporating
effect capable of being obtained from a given amount of heating surface
owing to the absence of soot and dust and the greater uniformity of
heating effect. For the same reasons also a considerable saving of fuel
and of labour will be effected.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles William Siemens in the Great Seal Patent
Office on the 7th October 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
ALL
WILLIAM SIEMENS, of No. 3, Great George Street, Westminster, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of April, in the year
of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles William Siemens, Her special
licence that I, the said Charles William Siemens, my executors, adminis-
trators, and assigns, or such others as I, the said Charles William
Siemens, 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

page_text: :
ΤΟ
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN THE APPLICATION OF GAS FURNACES
EVAPORATING, SMELTING, PUDDLING, AND OTHER MANUFACTURING PURPOSES," upon
the condition (amongst others) that I, the said Charles William Siemens,
iny 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 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, do hereby
declare the nature of the said Invention, and in what manifer the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
panying Drawings, and to the figures and letters marked thereon, that is
to say
1
In applying regenerative gas furnaces, as described in the Specification
to certain Letters Patent granted to me and Frederick Siemens, dated
22nd January 1861, No. 167, to certain chemical and metallurgical
operations, such as calcining and smelting of copper, lead, and other
ores, it is requisite to arrange the regenerators in a more accessible
manner than that described in the Specification to the said Patent in
order to clear them from the dust and ashes passing in with the hot
gaseous products of combustion. For this purpose, instead of con-
structing the regenerators in a vertical position and closely side by
side as was generally done heretofore, extending to a considerable
depth below the furnace, I arrange them horizontally beneath the
furnace, extending in some cases partially beyond the same, the two
regenerators of each pair being placed one above the other, by
preference the gas regenerator uppermost, and the two pairs being
so arranged by preference with passages between them or at the sides
or ends thereof as to be accessible for clearing them of deposits when
required. The walls of the regenerators are for this purpose in some
cases provided with closed side apertures for the introduction of
clearing tools, or in other cases the regenerators are so arranged
as to be readily cleaned or refilled from the top.
Closed apertures
are also provided in the roof of the furnace over the vertical passages
leading from the regenerators into the furnace in order to gain access

page_text: to these for clearing them of deposits.
This horizontal arrangement
of regenerators has the further advantage of requiring comparatively,
little depth below the ground line of the furnace, whereby the con-
struction thereof is facilitated. Each pair of regenerators may be
made to communicate with opposite ends of the furnace as in the
arrangement employed heretofore, but in cases where it is desirable
to make the furnace bed accessible from three sides, as in copper
and lead smelting furnaces, and also in puddling furnaces, I arrange
both pairs of regenerators to communicate with one and the same
end or side of the furnace. In this case the ascending gas and air
passages to each pair are generally made to unite in a small mixing
chamber just before entering the furnace, in which chamber the mixing
and ignition of the gases takes place, whereby, owing to the confined
space of each chamber preventing the expansion of the gases therein,
these are thrown in a jet through a tapering aperture in the chamber
into the furnace so as to pass right to the end of or across the bed, and
in returning to escape through the aperture conducting to the other pair
of regenerators.
Figures 1 to 4 on Sheet I. of the accompanying Drawings show the
before-described improved arrangements as applied to a puddling furnace.
Figure 1 shows a longitudinal section of the furnace; Figure 2 shows
a transverse section; Figure 3 shows a sectional plan of the puddling
hearth; and Figure 4 shews a sectional plan of the regenerators.
Similar letters of reference indicate similar parts in each of the Figures.
A, A, A', A', are the regenerators arranged horizontally beneath the
puddling furnace C, A, A, being the regenerators for heating the air,
and A¹, A', those for heating the gas. The form of the fire-brick slabs
for filling in the regenerators is shown to an enlarged scale in elevation
and section at. Figure 5. Both pairs of regenerators communicate
with one and the same end of the furnace by means of the passages
B, B, B', B'. The gas and air from one pair of regenerators in rising
through these passages enter one of the spaces D, the air above the
gas, where they are ignited, and whence the flame passes down the
passage E into the furnace C. After traversing the hearth the flames
and hot gases return through the other passages E and B, B', to the
other pair of regenerators. The passages B, B', are accessible through
man-holes closed with slabs F at top for clearing them from dust.
The regenerators may also be cleared of dust by removing a portion

page_text: of the brickwork coverings at G, G, and brushing or scraping off the
deposit which falls into the transverse spaces at the bottom, which
are made sufficiently large to take the deposits from several clearings,
and which are emptied when the regenerators are reset. The metal
on the hearth C is worked from the aperture H, and the slag is run
off through the tapping hole I in the usual manner. The furnace bed
is constructed of iron plates, round the sides of which are formed boxes
or troughs J, through which cold water is made to circulate in the
usual manner, the cold water entering the same through the pipe K,
arranged to pass backwards and forward beneath the floor plates in
front of the working hole to keep them cool. The bottom of the
furnace bed is also kept cool by the evaporation of water from the
tank L, in a similar manner to that described in the Specification to
my Patent, No. 2413, of 1866, ventilating passages M, M, being
provided at the back of the furnace to carry off the steam. The water
is supplied to the tank L by the overflow from the edges of the
troughs J, and flows off from the same through a waste pipe not
shewn. N, N are the reversing and regulating valves to the air
regenerators, and O, O', are the same to the gas regenerators. The
puddling furnace is here shewn as constructed in duplicate on either
side of the line V, V.
Figures 6 to 8 shew a copper or lead smelting furnace constructed
on a similar principle to that above described. Figure 6 shows a
longitudinal section, Figure 7 shews a transverse section, and Figure 8
shews a sectional plan through the gas regenerators. The regenerators
A, A, A', A', also arranged horizontally as before, have in this case
a passage G between them, in which access is gained to the regenerators
The
through the closed side apertures H for clearing them of dust.
regenerator bricks are all arranged as vertical slabs or brickwork
pillars, as shown, to facilitate such clearing out. The regenerators
all communicate with one and the same end of the hearth C through
the passages B, B', the gas and air rising from the one pair being
ignited in the one space D, while the flames, after passing from the
aperture thereof right across the hearth, escape through the other
aperture D down into the other pair of regenerators; N, O, are the.
reversing valves to the regenerators.
In constructing regenerative gas furnaces for the manufacture of.
glass on the open bed I construct the bottom of the bed of slabs or

page_text: plates of iron on which the glass may either form its own bed or upon
which a fire-brick bed is laid, and 1 construct the entire sides of the tank
or the upper portion thereof of a series of hollow iron boxes through
which cold water is made to circulate by means of pipes connecting
the separate boxes, and so arranged that they conduct the water from
the top of one box into the bottom of the next one.
Figures 9 and 10, on Sheet II. of the Drawings, show respectively a
longitudinal section and a transverse section of a furnace for making
glass on the open bed arranged as above described. The gas passages A
from the gas regenerators A communicate with the melting chamber C
at the level of the bridges D, while the air passages B' from the air
regenerators B are carried up. to near the arch E of the chamber, as
shown, so that the air passes into the heating chamber above the
combustible gas in a similar manner to that shewn with reference to
puddling furnaces in the Specification to my Patent, No. 2413 of
1866. The bed is composed of iron slabs or plates F carried by the
supports G, upon which slabs or plates is placed the fire-brick lining H.
The upper part of the sides of the bed consists of hollow iron boxes I,
through which cold water is made to circulate, entering at the bottom of
one box through the pipe i, and made to flow off from the top of
another box through the pipe ¹. The boxes are sometimes protected
from the heat by a covering of fire-brick, as shown. Air spaces are
formed beneath the bed to cool the same.
In applying regenerative gas furnaces to the manufacture of soda,
1 firstly arrange the salt cake furnace consisting of the roasting hearth
and evaporating pan with a set of horizontal regenerators beneath the
former, the regenerators being however so arranged that a certain
quantity of heated gas and air is made to pass from them beneath the
evaporating pan, and to heat the same by their combustion, the other
portion of the gas and air being conducted into the roasting hearth
through passages at opposite sides thereof. This arrangement is shown
at Figures 11 to 13, on Sheet II., of which Figure 11 shows a longi-
tudinal section through the roasting hearth and evaporating pan;
Figure 12 shows a part sectional plan of the same; and Figure 13 shows
a transverse section through the furnace. A, A, are the regenerators
communicating with the roasting hearth C through the passages B and
apertures B' at the opposite sides thereof, while at the one end they com-
municate through the passages D, D, and apertures D', D', with the

page_text: space E beneath the evaporating pan F. Into this space consequently
a portion of the heated gas and air pass from one set of the regene-
rators through the one aperture D', and after undergoing combustion
therein and heating the pan F the products of combustion escape
through the other aperture D' into the other set of regenerators.
The evaporating pan F communicates with the roasting hearth C through
an opening G, through which, when required, the materials are intro-
duced from the pan on to the hearth, and which at other times is closed
by a fire-clay plug or slab. For the conversion of the salt cake I intro-
duce the same, together with the requisite amount of lime and carbonaceous
matter, into a horizontal drum or cylinder, such as is described in the
Specification to Tooth's Patent, No. 3213 of 1863, having two opposite
central openings at the ends of the drum, through one of which I cause
to pass combustible gas and heated air entering through separate
passages, which gas and air enter into combustion in the drum as this
revolves, and heat the materials contained therein; or a furnace with solid
hearth of the usual form may be employed in the place of the revolving
drum. The hot gaseous products of combustion then pass through
the opposite end opening in the drum or furnace into a chamber
containing a series of pipes, through which the air required for effecting
the combustion in the drum or furnace is caused to pass, and thus
becomes heated to the requisite degree. The gases in entering this
chamber are made to descend and then to re-ascend, thus being made
to deposit their dust before entering the evaporating chamber containing
alkaline liquid, whence, after having taken up vapour from the surface
of the liquid, the gases escape into the chimney.
Figures 14 and 15 show respectively a sectional elevation and a
sectional plan of the before-described black ash furnace, arranged with a
revolving cylindrical bed or drum. The materials are introduced into
the revolving cylinder or drum C through an opening, not shewn,
through the one end opening of which drum the heated gas and air
enter from the gas and air passages A and B. After entering into com-
bustion in the cylinder or drum and acting upon the contents thereof,
the hot gases escape through the opposite opening E into the chamber F
for heating the air that has subsequently to effect the combustion of the
gas in the cylinder, as described. -For this purpose the air entering the
passage, G through the external aperture H is caused to pass through
the bent pipes I into the passage J, while at the same time the hot

page_text: gases from the cylinder C are caused by the partition K to descend and
to pass in contact with the external surfaces of the pipes 1, thus heating
the air passing through them. The gases then re-ascend on the other
side of the partition and pass into the evaporating chamber L, being
made by the descending and re-ascending motion to deposit the greater
portion of their dust in the chamber F. The heated air is conducted
through the flue J to the passage B, where it ascends and mixes with
the gas from the passage A, as above described. M is a valve for
regulating the quantity of combustible gas passing into the furnace
from the gas generators. The quantity of air may be regulated by the
slide N closing the inlet aperture H to the heating apparatus.
Man-holes 0, 0, are provided at the top of the latter for clearing out
from time to time the dust deposited by the gases. For the finishing
furnace I arrange a set of horizontal regenerators beneath a bed of
considerable length, the hot gas and air being made to pass into the
furnace alternately, at either end by the usual arrangement of reversing
valves or dampers, while the products of combustion escape at the
opposite end. Near each end of the furnace openings are formed
through the roof through which the drained soda ash is introduced
on to the bed in such a manner that the fresh charge is always
introduced at the end of the bed at which the products of combustion
are escaping, so as to be first acted upon by the lower heat of such
gases before being subjected to the more intense heat produced at that
end when the action of the furnace is reversed.
In applying regenerative gas furnaces to the burning and enamelling
of pottery and china, and to other similar processes which require
gradual heating and cooling, I arrange a series of two or more ovens,
kilns, or muffles over and in communication with one and the same set
of two pairs of regenerators, so that when one or more of the ovens,
kilns, or muffles are cut off from the regenerators, the heat accumu-
lated in these last shall be usefully employed in the heating one or more
other ovens, kilns, or muffles. For this purpose each pair of gas and
air regenerators communicates through openings provided with dampers,
with transverse passages situated beneath each of the kilns, whence
the gas and air, after mixing, pass either directly into the kiln and
enter into combustion there, or the combustion takes place in the
passages only, and the hot gases are made to pass through flues
surrounding the kiln, oven, or muffle, so as to heat, the goods con-

page_text: tained therein without coming in contact with such goods; or the
combustion may take place in those kilns in which processes are
carried on that are not injured by immediate contact with the gases,
and a portion of the hot products of combustion may then be made
to pass from each kiln through flues surrounding other kilns, ovens,
or muffles, situated by preference above those first named, and in which
the more delicate processes are carried on, the passage of the gases
through such flues and consequently the heat imparted to the upper
kilus being regulated by means of dampers closing apertures through
which the flues communicate either with the atmosphere or with a
chimney.
Figures 16, 17, and 18 show respectively a part longitudinal section,
a part sectional plan, and a part transverse section of a series of kilus
arranged in connection with one set of two pairs of regenerators, as
above described. Across the regenerators A, A, A', A', are arranged the
kilns or ovens B, B, under the floors of which are formed passages C, C,
and C, C', communicating respectively with the regenerators A, A',
through the passages a, a, a¹, a', provided with dampers c, c, c', c', by
which the communication between the kilns and regenerators can be cut
off.. The passages c, c', furthermore communicate with the kilns B
through the apertures b, b, so that the heated gas and air entering the
passages C, C, for instance, from the regenerators A, A, pass thence
through the apertures b, into the kiln, and after there entering into
combustion the hot gaseous products of combustion pass through the
apertures b' down into the other pair of regenerators. Above the
kilns B are constructed other kilns or muffles D for carrying on the
more delicate operations, such as glazing, enamelling, &c. Flues E
communicating at the lower ends with the interior of the kilns B pass
round the sides and tops of these muffles and communicate with the
atmosphere or with a chimney through openings E' at top, so that a
portion of the hot gases is caused to pass from the kilns B up through
the flues E, thus heating the muffles to the required extent. The
apertures E¹ of the flues E are provided with the dampers F, by means of
which the draught and consequently the heating of the muffles can be
regulated. By closing the dampers c, c¹, to the passages a, a¹, as before
stated, any one or more of the kilns or muffles may be cut off from the
regenerators when the goods contained therein require to be cooled and
removed.

page_text: In calcining ores and other metallurgical operations the employment
of currents of highly-heated air is sometimes desirable. To obtain
such heated currents I erect a pair of vertical regenerators of the
ordinary construction, with ascending gas passages between the two,
and I direct a current of atmospheric air alternately through the one or
the other generator in an upward direction, which on meeting the gas at
the upper extremity of the regenerators causes a flame, which in
descending through the second regenerator imparts heat to the same
preparatory to such heat being communicated to the ascending current
of atmospheric air. At or near the upper extremity of each regenerator
is an orifice capable of being opened or closed by a valve or brick slide,
so as to communicate at will with a passage leading to the calciner or
other apparatus where highly-heated air is required. The air passing
upwards through one of the regenerators being more than sufficient to
support the combustion of the gas, is made to pass in great part to the
calciner without entering into combustion.
Figures 19 and 20 show respectively a sectional elevation and a
sectional plan of a hot-blast stove constructed as above described. The
air is made to pass up through the one or the other of the rege-
nerators A, A', while the combustible gas ascends through the passage B
situate between the two regenerators. Arrived at the narrow aper-
tures C, C, the gas enters into combustion with a portion of the hot air
issuing from the top of the regenerator A or A', the resulting flames being
made to pass down through the other regenerator, while the remaining
portion of the heated air issues through the apertures D or D' into the
passage E, conducting it to wherever required. The proportion of air
entering into combustion with the gas is regulated by a valve or damper,
not shown, in the flue, through which the products of combustion pass
away to the chimney. The apertures D, D', may be provided with dampers,
not shown, whereby the one situated in the regenerator in which the
products of combustion descend is kept closed until the action of the re-
generators is reversed, when the position of the dampers is also reversed;
but such dampers may be omitted, and the heated air be withdrawn
without intermixing with the products of combustion by narrowing the
passages C, C, and regulating the draught by the chimney damper and the
damper F, allowing some air to pass through D and D' to complete the
combustion of the gas.

page_text: I conduct the combustible gas from the gas producers through tapering
jets into the one end of the flues of the boiler, such jets being
made to pass through passages in front of the flues through which
the air required for the combustion is made to pass, entering the
flues through annular orifices surrounding the gas jets.
The perfect
combustion of the gas and air is further facilitated by the intro-
duction of rings of fire-clay into the boiler flues at a short distance
in front of the gas jets, and which become highly heated by the
impinging of the flames upon them. The flames and products of com-
bustion after traversing the internal and side flues of the boiler are
caused to impart the greater portion of their remaining heat to a series
of pipes through which the air required for the combustion is caused to
pass, and the gases afterwards escape into the chimney with only such
an amount of heat as is requisite for producing the necessary draught
Figures 21, 22, and 23 show respectively a longitudinal section and
two transverse sections of a double-flued Cornish steam boiler with
heating apparatus, arranged as above described. Combustible gas
ascends from the gas flue A leading from the gas regenerators through
the tubes B, B, whence it issues through tapering pipes C, C, into the
flue D of the boiler; at the same time atmospheric air ascends from the
flue E through the pipes or boxes F through which the tubes C pass,
and issue through annular openings G surrounding the tubes C
together with the combustible gas into the flue D. The mixture of gas
and air having been ignited either through small apertures in the
surfaces of the boxes F or through the small tubes. H passing centrally
through the gas tubes the resulting jets of highly-heated flames are
made to impinge upon and pass through the fire-brick rings I fixed in
the flue D, which are thereby heated to a high degree, and thus effect
the more perfect combustion of the carbonaceous gases. The flames
after traversing the flues D and side flues J are caused, in escaping to
the chimney through the bottom. flue K, to come in contact with and
impart a great portion of their heat to the series of bent pipes L,.
through which the atmospheric air destined for the before-described
combustion with the gas is caused to pass, and thus to become con-
siderably heated before entering the flue E. The air is conducted to
the said heating apparatus through flues M, which it enters through
the boxes N provided with slides O for regulating the quantity of air
passing in.
The gas passages are also provided with regulating valves,
so as to produce any degree of heat. required. The small tubes H are

page_text: provided with plugs at their outer ends, and serve both for igniting
the gases, for observing the state of their combustion, and for admitting
more air to the flame when necessary. This arrangement may with
advantage be applied to marine boilers, in which case the requisite
gas producers are erected in a separate portion of the vessel, a
large collecting gas tube or tubes conducting the gas from the pro-
ducers to the front of the boilers with a branch furnished with a
regulating valve descending to each fire-place.
The tubular arrange-
ment for heating the incoming air may be conveniently placed at
the base of the chimney stack. The advantages of this arrange-
ment are, the entire absence of smoke from the chimney and the
greater evaporating effect capable of being obtained from a given amount
of heating surface owing to the absence of soot and dust and the greater
uniformity of heating effect. For the same reasons also a considerable
saving of fuel and of labour will be effected.
In regenerative furnaces, where the regenerators are placed in a
horizontal position, I sometimes arrange the reversing valves to the gas
and air passages to revolve upon a vertical axis, and the two valves may
be conveniently placed one above the other with the chimney flue
between them, and both actuated by one and the same spindle.
Figures 24 and 25, on Sheet I. of the Drawings, show respectively a
part longitudinal and part longitudinal and part transverse section of the
gas and air passages and valves' of a furnace in which this arrangement is
adopted. I is the reversing valve to the gas passages, and P is the
reversing valve to the air passages.
These are both fixed to one and the
same vertical spindle Q, by means of which they are made to revolve
simultaneously in the cylindrical casings R, S. The chimney flue T com-
municates with a box T' situated between the two valves, and is provided
with a regulating valve U. Similar valves V and W are also provided in
the gas and air passages, as shown in Figure 25. The reversing valves
being in the position shown in Figure 24, the gas and air would enter
respectively the regenerators A and B, while the products of combustion
would at same time escape from the regenerators A', B', into the box T',
and thence into the chimney flue T. One advantage of this arrangement
of reversing valves is, that the valve flaps can be lifted out readily for
inspection by simply removing the cover X of the gas-box.
Having thus described the nature of my Invention, and the best
means I am acquainted with of performing the same, I wish it to be

page_text: understood that I do not confine myself to the precise details of the
various arrangements as shown on the accompanying Drawings; but
what I claim is,-
First. Constructing horizontal regenerators in pairs with the gas
regenerator uppermost, and so arranged that a great development of zig-
zag passages and heat-absorbing surface is obtained without harbouring
places for dust, which latter is at liberty to fall into recesses whence
it may be removed in case of rapid accumulation through side
openings, substantially as described with reference to Figures 1 to 8 of
the accompanying Drawings.
Second. Arranging puddling and smelting furnaces with horizontal
regenerators in such manner that the heated gas and air rise vertically
from the regenerators, and are thrown, the air uppermost, into the
furnace, both sets of regenerators being made to communicate with one
and the same side of the furnace opposite the working hole, the object
being to throw the flame well forward, and to leave three sides of
the furnace accessible, substantially as described with reference to
Figures 1 to 8.
Third. Reversing and regulating the currents of gas and air through
horizontal regenerators by means of revolving valves upon one and
the same spindle, substantially as described with reference to Figures 24
and 25.
Fourth. Constructing soda ash furnaces in such a manner that com-
bustible gas and heated air are admitted in a state of combustion into
a rotating cylinder or stationary furnace bed containing the soda ash,
the flame passing from such cylinder through a condensing and air-
heating chamber, and thence over the surface of the evaporating soda
liquor, substantially as described with reference to Figures 14 and 15.
Fifth. Constructing soda finishing furnaces with horizontal rege-
nerators below a long furnace bed with two feeding hoppers, to be
worked in such manner that the flames pass always from the side where
the soda is already dry and heated to the side where fresh material has
been charged, the reversing of the gaseous currents being in this case
accommodated to the nature of the work, substantially as described.
Sixth. So arranging regenerators for heating salt cake furnaces that
one portion of the heated gas and air is caused to pass into the roasting
hearth, while another portion thereof from the same regenerators is
'

page_text: caused to pass beneath and to heat the evaporating pan, substantially as
described with reference to Figures 11 to 13 of the Drawings.
Seventh. So constructing hot-blast stoves of a pair of regenerators
and a passage or passages for combustible gas that a portion of. the
heated air passing up through one of the regenerators is made to
enter into combustion with the combustible gas for the purpose of
heating the other regenerator, while the other portion of the heated
air is conducted away through an aperture to wherever required,
substantially as described with reference to Figures 19 and 20.
Eighth. Arranging one set of four regenerators in combination with
several muflles, kilns, or chambers for burning, glazing, and annealing
pottery or other ware in such a manner that each chamber may be
heated and cooled separately without disturbing the continuous and
regular action of the regenerators, substantially as described with
reference to Figures 16, 17, and 18.
Ninth. Arranging regenerative gas furnaces for melting glass upon
the open flame bed of a furnace by constructing such bed in the form
of an iron tank, cooled externally by currents of air and water,
substantially as described with reference to Figures 9 and 10.
Tenth. Constructing apparatus for heating steam boilers by means of
gaseous fuel and heated atmospheric air, wherein the gas and air are
caused to enter in concentric jets made to impinge upon fire-brick
rings, the air being previously heated by passing through a series of
pipes situated in the chimney flue of the boiler, substantially as
described with reference to Figures 21 to 23.
In witness whereof, I, the said Charles William Siemens, have
hereunto set my hand and seal, this Seventh day of October, in
the year of our Lord One thousand eight hundred and sixty-eight.
Witness,
CHAS. D. ABEL,
20, Southampton Buildings.
C. W. SIEMENS. (L.S.)