Improvements in Furnaces for Smelting and other Purposes and in Gas Generators therefor.
Year: 1899

page_text: Date of Application, 12th Apr., 1899-Accepted, 7th Oct., 1899
COMPLETE SPECIFICATION.
Improvements in Furnaces for Smelting and other Purposes and in
Gas Generators therefor.
We, JOHANN TERÉNY, of Zolyom Brezo, Engineer, and BELA UHLYARIK, of
Kigyo uteza 7, Contractor, of Budapest, both in the Kingdom of Hungary, do
hereby declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
This invention relates to improvements in furnaces heated directly by gas
and in gas generators therefor and in the arrangements connected therewith
and in which with feeble and wet combustibles high temperatures can be obtained
for smelting and other purposes. In this invention the gas generators are
arranged in direct connection with the furnaces so that the expensive bringing
of the gas from great distances is not required and a loss of heat originated by
the cooling of the gas is avoided.
For this purpose two generators which can be put alternately into function,
are joined to the furnace, see Fig. 1 one of them serves for producing gas or gases
which gas passes through the second being there heated by which means the
direction of flow of the gas can be reversed without the use of gas regenerating
chambers inasmuch as the functions of the same are performed by the generators
themselves whereby the glowing coal takes the place of the usual clay grating.
This manner of heating the gases seems the most rational as besides the advan-
tage, that no separate gas regenerators are required, the gases are at the same time
whilst being heated by the generator also purified, the soot particles, tar, vapours
carbonic acid, oxygen and other secondary products being here undesirable and
which are more or less always originated by any gas generator are either
retained in the gas purifying generator or by the glow of the fuel transformed
into valuable gas consequently the purity of the gas is assured even with little
or negligent attention. Not only the formation of the undesirable tar and soot
is avoided but by their decomposition the gas is enriched with useful matter
thus an economy of combustible ensues.
For this purpose it is necessary that the gas generator for the greatest part
must produce dry gas, as if the gas contains much tar and other ingredients
wet and difficult to fuse as well as vapours, the gas purifying generator would
use its own heat for decomposing these secondary products and the remaining
heat would be insufficient to heat the gas to the required high temperature.
By suitable construction and arrangement of the generators they can be made
to produce gas mostly dry.
On account of the provision of two generators for alternate use, the filling
with fresh fuel is divided between the two and consequently also the production
of wet secondary products is reduced to half the quantity. In this invention
the air comes in contact with a proportionally large base of the generator, by
.which the quantity of good gas obtained during the production is increased in

page_text: a large degree contrary to the distilling process which produces as known mostly
only water and tar vapours and therefore is accompanied by a large consumption
of heat.
The production of good and dry gas can be further increased by introducing
heated air into the generator.
For carrying out the above mentioned purposes and improvements two alter-
native constructions are represented in the drawing, in which Figs. 1-3 show
a construction for the reduction of the more wet material into gas and Figs. 4-6
a construction for the reduction of drier. material into gas.
Figs. 13 show a large reheating furnace, but any different but suitable
construction of the treatment chamber of the furnace can be used.
The pit shaped generators are constructed directly on both sides of the furnace.
The flues of the generators c c are inclined on both sides towards or over the
fire bridge d d of the furnace by which its lower face is continually in contact
with the flame from the fire bridge (Fig. 1).
This arrangement renders it possible to give back to the generators a large
quantity of their heat which is utilized for very wet combustibles for decomposing
the vapours which constitutes a supply which practically costs nothing and
whose store of heat is lost by other constructions. By this means the generator
which would be cooled by the great loss of warmth is constantly enabled to heat
the gas with its own warmth.
Each generator is provided with a flat grate a combined with a step grate b,
the ash pit of which is closed in an air tight manner by means of four doors e
(Figs. 1, 2).
Into this ash pit air is blown through a pipe (Fig. 1). The bars of the
flat grate are movable by means of an agitating device Fig. 8 consisting of an
axle whereon underneath each second grate bar a cam is arranged, to be turned
in any suitable manner; a wheel is connected with the axle. By this means
the whole mass of coal is ignited, the falling of the ashes and small pieces of
coal is assisted and an equal flow of the gas is effected.
The fuel rests on the oblique part of the suitably inclined pit but immediately
slides downward as soon as in consequence of the consumption of the coal under-
neath a gap is originated. This oblique part consisting of ribbed clay plates
upon which bricks have been laid and which is exchangeable, being continually
exposed to the radiated heat from the fire bridge d, the coal there lying is
subjected to a dry distillation, the products of which are forced to pass through
the glowing coal layer at the lower part of the pit c whereby they are decom-
posed and so pass together with the dry gas passing upwards in the collecting
room which is constructed in the roof and from there pass through the con-
necting channels f (Fig. 2) arranged in the long walls of the furnace at both
sides into the other generator for further heating.
These connecting channels f are preferably constructed of rivetted iron sheets
and are built into the long walls of the furnace between the upper edges of
the doors and the roof in such a manner that they in no way hinder but on
the contrary conduct the radiated heat from the side walls of the furnace for
heating the gas before it goes into the regenerating gas generator. Both ends
of the channels f are provided with openings closed by doors, for cleaning the
channels. These doors are at the same time safety valves. The alternate work-
ing of the generators respectively the altering of the flow direction of the gas
is effected by means of flap valves g which also can be replaced by clay valves
one of which is seated in each of the three cornered chambers arranged in the
gas channel, the arms h of these valves are provided with counter weights and
joined by a mutual actuating rod i Fig. 1. By means of the lever arm y arranged
in the centre of the actuating rod i, the operation is effected. For heating the
combustion air ordinary upright Siemens regenerating chambers & are arranged,
the guiding of the air and gas smoke is effected by means of a mutual changing
valve the turning arm w of which jeined by a rod m with the knee lever n.

page_text: Connected to the same rod m is also the turning arm o of the ventilator p provided
with double openings.
Consequently all guidance of the gases etc. is done with one movement by
the lever arms arranged approximately in the middle of the furnace.
The working and function of the furnace is the following:-
-
The two generators 1 and 2 are filled by means of the charging openings s with
wood remainders and logs. Then the gas valves g and the changing valve / are
brought into their mean position and the doors e opened (Figs. 1 and 2) whereby
the first wet gases are drawn into the chimney from both sides through the
channels u and t and the regenerators k for such time until the wood becomes
glowing. The treatment chamber g of the furnace must naturally before the
putting into action of the generators, be heated with wood fuel. Then the two
generators are about three quarters filled with coals and are later on entirely
filled and all the valves of the furnace are put into the position shown in Fig. 1,
that is, into such a position that the flame can go from the left hand side into
the treating chamber. The air valve r (Figs. 3 and 2) and the doors e of the
generators are closed whereupon air is slowly blown in. By the air blast the gas
production in generator 2 begins whilst the generator 1 acts as gas heater. The
gas ascending from generator 2 to the roof passes along the channel v, through
the channels at both sides to the left into the collecting channel of the genera-
tor 1 and from there through the live coals heated to a high temperature, it then
passes through the gas delivery opening open at the right hand of the flat
grate a into the gas channel u and from there to the fire bridge d. For a certain
time the gas streams unburnt into the chimney. Later on the air valve ris
cautiously opened by means of the turning wheel 3 (Fig. 3) whereupon the
combustion air coming into the valve 7, streams through channel 4 into the
chamber and becoming heated there, passes through the opening arranged in
the roof into the air channel t and from there to the fire bridge d where the hot
air mixed with the heated gas leads the flame through the fire room and the
greatest part of its warmth is utilized for the desired purpose. The combustion
products go through the channel t on the right into the right regenerative cham-
ber and, having delivered their warmth to the latter, they go through channel 4
into the air box and from there into the funnel channel 6.
For altering the direction of flow of the gases which at the commencement of
the process is often required but in regular working according to the quality
of the coals is done every quarter or half hour, the valves are put into the opposite
position by turning the levers / and whereupon the gas and air take the
opposite course.
As the gas would be enabled by the above described reversing of the flow to pass
also into the ash pit of the gas heating generator and to form with the air
an explosive mixture there, air is blown with slight pressure into both ash pits
through a small pipe 7 thus preventing the gas flowing into the ash pits.
The generators and the regenerator chambers are only successively heated.
When the furnace is working at the normal, the charging of the gas producing
generator must always be effected before the reversing of the gas flow measure
proportional to the gas flow. The bottom of the pit must in working, always
be covered with coal.
The regulation of the flowing in of gas is effected so that the extreme positions
of the turning arms of the valves g are fixed in opening or closing by shoulders
proportionally to the flowing in of gas. When this opening distance which
becomes less when the pressure of gas augments has once been fixed, it is best
not to alter the same, the fluctuations in the gas streaming originated by the
changing resistances are balanced by the air blast by means of a throttle valve
arranged in the passage which can be worked automatically.
The regulation of the air draught is operated by the rising or lowering of the
valver which is effected by means of the wheel 3 Fig. 3.
By the above described arrangement of the furnace with its generators, inclined

page_text: '
above the fire bridges, dry and heated gas can be produced from very wet com-
bustibles.
For some purposes very high temperatures are unnecessary or drier combusti-
bles of less heating value are used. In these casca a more cimple arrangement
as shown in Figs. 4 to 6 is sufficient.
In this arrangement the generators are not built in one with the furnace but
they stand free at both sides of the same. Consequently the connecting channel
10 of the generators lies also free.
Both generators have substantially the form of a truncated pyramid. For
the blast two different arrangements, according to the quality of the combustibles,
are used. The one is represented on generator 1, the other on generator 2. That
of generator 1 is used only for materials easily reduced into gas and consist of
the slightly inclined fire grate a underneath which a cast iron ash box 11 is
arranged in such a manner that the blast pipe 12 enters it operating on the
underside of the grate. In order to avoid explosions when reversing the action
of the generators a low air pressure is constantly maintained in both ash pits.
The arrangement shown for generator 2 is more for clinkers or large coal and
the blast works from above by means of two nozzles 12 arranged opposite each
other from whence the blast passes to a central wall 13, so that the heating is
effected where it is most required, that is at the gas delivery opening.
The use of a grate is necessary for the ready removal of the ashes and small
coal the ash box being divided into two parts with regard to the central wall 13.
The mechanical agitating of the grate bars is here also applied to the whole
grate (Figs. 7 and 8).
For cleaning the ash pits each of them is provided with two air excluding
doors 5. For taking away the slag stones and coal remainders two doors 8 are
arranged above the grate. The charging chamber being under gas pressure
and as much gas could escape unless the same is tightly closed, the trap 16
of the cylindrical charging chamber is provided with a sand packing and further
for preventing the coal from dropping down into the funnel, the latter is cylin-
drically prolonged at its lower end. At the end of this cylinder the sand channel
is arranged by which means by letting the fuel down quickly the same will fall
in the suitable direction without touching the sand packing. The upper cover 17
is provided with a water packing and in order to prevent the gas from forcing
the water out of it, the channel is deeper than usual.
The gas channels of both generators are connected by a channel 10 of riveted
iron sheet covered with light fire bricks or the like. From the centre of this
channel a chimney pipe 19 rises which can be closed by a valve 18 and which is
used for allowing the escape of the preliminary produced bad gases. For cleaning
purposes opposite each end of the connecting channel 10, pipes 20 arranged with
trap doors are provided in the walls of the generators. These doors are used
at the same time as safety valves.
A further arrangement is to be described for reducing less wet materials into
gas. For heating the air, an air heater or so called recuperator is arranged
which is preferably arranged adjacent to the furnace.
This recuperator 21 Fig. 4 is composed of clay plates which form two kinds
of channels. The channels 1, 3, 5, 7, 9 used for the passage of the air, have for
the purpose of enlarging this heating space a zigzag form; the channels 2, 4,
6, 8 are for leading the furnace gas in a direction opposite the air flow. By this
counter flow of air and gas the former is successively heated.
The manufacture of clay plates of large area being exceedingly difficult, the
recuperator 21 can also suitably be made in two stories; the single plates fit
closely on the top in the middle and at their lower ends into suitable depressions
of the covering plates 22 which are a little thicker. In the length direction each
single wall is composed in a suitable manner of a variety of plates (Fig. 5). Clay
plates 23 connect the ends and are arranged between ribs.
The furnace gas passes as can be seen in Fig. 6 by the openings 24 into the

page_text: recuperator through similar openings 25 out of it. The air channels end in
one of the closed rooms arranged on each end of the recuperator, at one of its
ends is a suction chamber 26 which can be closed by a trap door 27 from there
the cleaning of the gas channels is effected. In the roof 28 of this suction
chamber an air valve 29 is arranged for regulating the flowing in of the air.
The other end of the air channels end in a small closed channel 30 which passes
at both ends into the side walls of the recuperator 21, ascends from there through
two vertical openings 31 in order to pass into a channel 34 at the level of the
air chamber under the hearth, from whence on the right and the left a vertical
channel 35 leads into the air channel under the furnace from the latter the air
can pass into the air channels 36 of the furnace.
Round openings closed with plugs 37 (Figs. 5 and 6) are arranged on the fore
end of the gas channels of the recuperator for the purpose of allowing their
cleaning which are removed one by one and the deposit lying on the bottom
of the channels can be brushed into the channel 38 underneath the recuperator 21.
In the meantime the combustion products can pass undisturbed through the
channels 2, 4, 6, 8. The cleaning can therefore be done whilst the furnace is
working.
The connection of the generators with the furnace is such that from each
of the gas outlet openings 39 of the generator a channel 40 leads into the gas
channel 41 of the furnace.
Immediately outside the furnace wail gas current changing cocks 42 421 are
seated in the channels, one of them is always open whilst the other one is closed.
The connection between the recuperator 21 and the furnace must also be such
that a change in the direction of the flame can be effected. This is obtained
by providing one opening for the air gas and one for the furnace gas, each of
them being divided in the middle of the furnace by an intermediate wall 43"
Fig. 5 whereby for the furnace gas flowing from both directions as well as for
the air a separate way is provided. The passage of the smoke gas to the recu-
perator 21 is such that the gas passing through the gas outlet opening underneath
the furnace, divided by an intermediate wall, is conducted by the double channel
32 to the changing cock 44, 44¹ and from there further on through the channel 45
Fig. 6 to the gas admission opening of the recuperator 21.
In a similar manner the air communicates with the furnace. In the channels
46 going under the furnace, air changing valves 47 47' are arranged, so as to
be able to guide the air of the generator room 21 to the fire bridge on the right
or the left. All the channels being arranged vertically on the furnace, the
changing cocks outside the furnace can, which is most important, be arranged
in one line, whereby in the position represented in the drawing, all the cocks
can be turned by a single hand movement, when their lever arms are connected
with the same rod 48. Moreover the turning arm 50 of the blast valve 49 pro-
vided with two openings can be brought into connection with this same rod
so that the respective workman in turning the changing cocks can also reverse
the action of the generators.
The working and function of the above described furnace is as follows:
In order to put the furnace into operation it is first thoroughly heated with
wood fuel. When the wood in the fire room is glowing the combustion products
flowing thence through both sides are let out after reversing, now on the one
side, now on the other. Then the generator can be put into action in a similar
manner as, by the previous described arrangement with the only difference that
the
gas first originated is allowed to escape by opening the valve 18 for so long
through the chimney 19 from both sides till the generators work in the normal
manner. After the gas is sufficiently pure and the furnace heated in a suitable
manner, the valve 18 is closed and all the valves of the furnace are then put
into the position of Fig. 5: 421, 44 471 being open and 42, 441, 47 being closed
by which positions the flame goes from the right side into the treatment chamber.
The air valve 29 is consequently previously closed.

page_text: Generator 1 acting as gas generator is again charged whilst in generator 2
the charge and blast cease. The gas in generator 1 then ascends into the junction
channel 10 and from there they go toward the right into generator 2. From here
the gas descends through the heated mass of coals from there purified and heated
to a high temperature through the opening 39 at the bottom of the shaft into
the gas channel 40, and ascend by the open valve 421 through the gas channel 41
to the right fire bridge. The gas generator 2 acts therefor as regenerator. The
gas flows out previously for a certain time unburnt through the chimney.
Then the combustion air is by cautiously opening the air valve 29 blown into
the suction chamber 26 of the recuperator 21 in order to be heated in going
through the air channels 1, 3, 5, 7, 9 toward the right. Then the currents
are assembled in the air channel 30 ascending from there through the opening 31
to be united in channel 34 from where the heated air ascends through the small
channel 46 on the right side, cock 471 being open, into the air chamber 33
underneath the furnace and from there through the air channel 36 of the furnace
to the furnace bridge in order to be joined there with the previously heated
gases there present for heating them to a high temperature and ignites them.
The ignited mixture of gas and air travels in the treatment chamber from the
right to the left and delivers most of its warmth. From the right side fire
bridge 51 the flame shoots downward through the gas channel 41; the furnace
gas however passes, gas cock 41 being closed, through the gas room underneath
the furnace toward the right to the intermediate wall 43 and from there past the
cock 44 through the channel 32 to the gas outlet opening 24 of the recuperator.
The smoke gas goes then into the gas channels 2, 4, 6, 8 of the recuperator 21
and after having delivered their superfluous warmth they flow to the lower gas
outlet opening 25 and from there into the chimney to pass from here through
the chimney to the outside if they can not be used for other purposes as for
instance boiler heating.
For reversing the action of the apparatus the furnace man can bring all the
valves into the opposite position by pulling the drawing rod after generator 2
now serving as gas generator, has been recharged.
Then the flame takes an opposite direction and the gas generator 1 acts as
gas heating chamber.
Even if the generator 2 has been charged afresh at the same time there will
be notwithstanding enough gas originated in it although previously cooled a
little.
In the mean time till the generator is again suitably heated the distilling of
the materials is going on and this is advantageous inasmuch as in the gas
originator in which newly originated gas is present, there is now the highest
temperature reigning and consequently all this gas can be transformed into
good gas.
In the same degree as the gas generator loses its high temperature the gas
of the gas regenerator becomes purer and hotter.
The two generators counteract therefore the differences which take place at
certain intervals with regard to the composition and temperature of the gas.
This relates to both kinds of apparatus described. Often repeated gas analyses
during the time of reversing and observance of the flame in the furnace furnish
sufficient guidance for keeping note of the times within which the reversing of
the generators has to be done.
The drawings show only an example of the described system of furnaces which
may vary in details and combinations as long as the described principal and
effect is obtained.
Of course the system can be used also for simple draught generators for one
direction only of the flame. For this case the gas generators are arranged at
the one end of the furnace so that the gas chamber comes over the fire bridge
and all the reversing arrangements in the furnace itself are dispensed with.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what
we claim is :-
1. An improved furnace having gas generators therefor in which the formation
and heating of the gas is effected by generators 1 and 2 the action being so carried
out in the generators, exchangeable in their function, that whilst one of them
produces gas, this gas, passing through the glowing mass of fuel contained in
the other generator is there heated and purified and its heating value augmented.
2. In an improved furnace as in Claim 1 the arrangement of a grate agitating
device wherein the agitating of the movable grate bars is caused by turning in
any suitable manner a shaft carrying suitable cams in operative connection with
said bars.
3. In a furnace as in Claim 1 the use of an air heater 21 constructed of clay
plates or the like which form air and smoke channels alternately through which
alternate channels the smoke gas and air pass at the same time but in opposite
directions means being provided whereby the air-heater can be cleaned during
action.
HERBERT HADDAN & Co., .
Agents to Applicants,
18, Buckingham Street, Strand, W.C.