IMPROVE- MENTS IN GAS-FURNACES
Year: 1882

page_text: LETTERS PATENT to Charles Denton Abel of No 28 Southampton Buildings
Chancery Lane in the County of Middlesex for an invention of "IMPROVE-
MENTS IN GAS-FURNACES " A communication to him from Abroad by the
Stettiner Chamotte-Fabrik Actien-Gesellschaft vormals Didier, an incorporated
Company of Stettin in the German Empire
COMPLETE SPECIFICATION filed by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 24th August 1882.
CHARLES DENTON ABEL of No 28 Southampton Buildings Chancery Lane in
the County of Middlesex "IMPROVEMENTS IN GAS-FURNACES" A communi-
cation to me from Abroad by the Stettiner Chamotte-Fabrik Actien-Gesellschaft
vormals Didier, an incorporated Company of Stettin in the German Empire
"
These improvements have reference to gas-furnaces or furnaces worked by
gaseous fuel more especially in their application to retort furnaces for the
production of illuminating gas, and relate to the arrangement of the "generator
or "producer" in combination with the "regenerative" system, ie, the useful
employment of the escaping heat of the furnace.
Combustible gases are generated in the producer by means of solid fuel of any
description, preferably coke, and a mixture of hot air and hot steam, in such a
way that the earthy constituents of the fuel form on the fire-grate a porous layer
of ash through which the air can easily pass.
The steam, introduced in the producer is not generated by the heat of the fuel
therein or by that of the residues of its combustion, but in a continuous way by
the hot gaseous products of combustion escaping from the furnace.
Air and steam are mixed together and are beated by the said escaping gases
before entering the producer.
In order to avoid the formation of slag and to prevent the fusion of the earthy
residues, and on the other hand to favor the formation of a porous layer of ashes
for the passage of air, it is necessary that the quantity of steam shall be in a

page_text: definite proportion to the air, entering the producer, such proportion depending
upon the chemical constitution of the earthy constituents of the fuel, and upon the
temperature of the mixture of steam and air entering the producer.
The construction of the furnace permits of the regulation of the proportion of
air to steam, according to the nature of the fuel, and to permanently maintain such
correct proportion. For this purpose arrangements are provided for producing
steam by means of the escaping heat of the furnace in any desired quantities and
to regulate the same with reference to the supply of air, the mode of working the
furnace being such that the finally determined proportion of air and steam is
maintained continuously and automatically.
Although the gas producer has been described as being combined directly with
the furnace, whose products of combustion escape at a high temperature, the
production of steam and heating of air may also be effected automatically by means
of other sources of heat as for instance by means of the hot producer gases.
This arrangement may be suitably employed in such cases in which the products
of combustion escape from the furnace at a low temperature.
The described arrangements, in addition to determining the nature of the
residues of combustion necessary for the regular production of gas and the ready
removal of the earthy constituents, also enable an improvement in the quality of
the producer gases to be effected, as the surplus heat of the producer being
rendered latent in the chemical action of converting the steam into combustible
gases (hydrogen and carbonic oxide) is thus introduced into the furnace to be
heated.
The porous nature of the ashes on the grate, in permitting the free passage of
air and steam, enables the producer to be worked with only a slight natural
draught, and permits of the perfectly uniform production of gas for a long time
without requiring removal of the ashes. By this means the manual labor is
reduced to a minimum. The perfectly uniform production of gas allows further-
more of an accurate regulation of the air required for combustion with the
producer gases, and effects a perfect and uniform combustion with a minimum
of air,
The accompanying drawings shew the above described arrangements applied
to a retort furnace on the "Munich" system for the production of illuminating gas.
Fig 1 is a vertical section through the gas producer, the retort furnace and the
regenerator on line a b. Fig 2 is a vertical section through the furnace and the
regenerator on the line c d. Fig 3 is a vertical section through the producer on
line ef. Fig 4 is a vertical section through the producer on line g h. Fig 5 is a
horizontal section through the producer and the regenerator on lines i k l m.
The fuel is thrown into the feeding opening at the top of the producer which is
provided at its bottom with a fire grate. The producer consists of four independent
parts, namely first, of an evaporating device, second of an ash chamber, third, of
a chamber for producing gas, and fourth, of a feeding chamber. The air necessary
to produce gas from the fuel, enters through the adjustable opening A and is mixed
with steam, coming from the tank B. This mixture of air and steam passes
through the channels c c³, c² c³, (Fig 5) whose walls are heated by the escaping
heat of combustion; the mixture thus heated then passes through the grate D and
the ash chamber E into the gas producing chamber.
The gases produced by the decomposition of hot steam and the partial combustion
of fuel in air, pass away through the channels F F', into the retort furnace where
they enter into combustion within the burners G G¹ with the heated air, coming
from the regenerator. The combustion gases H pass through the furnace in the
direction of the arrows, leave it at the rear of the channel L and enter the
regenerator, where they pass through the channels M, M1, M2, M3, situated between
the channels N, N¹, N2, Ñ³, N, through which the air supply to the furnace passes,
then through the channels M* through the walls of which their heat is imparted to
the mixture of steam and air on its way to the producer; the gases then pass
underneath the bottom of the tank so as to assist in the evaporation of the water,

page_text: and finally they pass through M into the chimney flue O. The channels are
arranged in such a way that the heated gases are caused to flow upwards and the
cooled gases downwards, that is to say, the currents are caused to flow in contrary
directions according to the well known system. The escaping heat of the fuel is
used therefor successively to heat firstly the air supply to the furnace, secondly to
heat the air supply for the producer, and finally to generate steam
In order to accelerate the transmission of heat from the products of combustion to
the air supply and also to render the construction of the regenerator more durable,
the channels have perforated partitions which increase the heat absorbing and
heating surfaces thereof. The damper for regulating the chimney draught is
situated behind the regenerator and not behind the furnace in order that the
difference of pressure in the adjacent passages of the former may be made as small
as possible.
As in the described arrangement the steam required for the producer is generated
by the escaping products of combustion, and as the quantity of the latter is directly
dependent on the amount of fuel converted in the producer, or on the quantity
of air supplied thereto, the quantity of steam produced will, under the regular
action of the furnace always be in a constant proportion to the air supply to the
producer. If a greater quantity of fuel is consumed in the producer and a
correspondingly greater amount of gases are burnt in the furnace a corresponding
increase in the quantity of water evaporated by the products of combustion will
take place. The proportions of the several parts of the furnace as shewn on the
drawings are so arranged that a sufficient quantity of steam can under all
circumstances be produced for preventing the formation of slag. In order to
regulate the proportion of air and steam for different descriptions of fuel, according
to the nature of their earthy constituents, or according to any desired temperature
at which the mixture is required to enter the producer, arrangements are provided
for adjusting the evaporation to the most favorable proportion. This is effected by
opening the regulating damper P so as to admit more or less cold air beneath the
water tank, thereby reducing the temperature of the products of combustion to
the required degree. The evaporation being thus adjusted, it will be automatically
maintained by the action of the furnace.
When a certain quantity of fuel has been consumed in the producer a propor-
tinate quantity of porous ash will have accumulated over the grate. The porosity
of this layer is so great that the regular production of gass will not be at all effected
even when it is of some thickness. The working of the producer can therefore
continue without attention until the entire space above the grate is filled with the
residues of combustion. With a construction of furnace such as described with
8 gas retorts, and with the employment of coke having from 14 to 16 per cent of
ashes this period of working can extend to at least 24 hours.
The ash chamber E being full of ashes they are removed for which purpose iron
bars are introduced through the openings QQ'(which are usually closed) so as to
intercept the fuel, after which the covers R and S in the front of the furnace ars
removed and the ashes are raked out through the openings, which operations will
not take more than 10 minutes. The openings are then closed again and the
producer continues to operate regularly as before until another period of 24 hours
has expired.
The water evaporated from the tank B is replaced by a continuous supply through
the pipe T. In starting the furnace the regenerator can be cut off and the gaseous
products of combustion can be made to pass directly to the chimney flue ○ through
the passages U, which are usually closed.
Although I have shewn this improved construction of furnace as applied to
the heating of gas retorts, it is equally applicable to metallurgical and other
purposes.
Having thus described the nature of this invention and in what manner the same
is to be performed as communicated to me by my foreign correspondents, I wish it

page_text: to be understood that I am aware that steam has already been introduced together
with air into gas producers and I do not claim this generally, but I claim :-
First. In gas furnaces the herein described mode of producing and employing
a mixture of hot air and steam for converting the fuel into combustible gases
whereby the formation of slag is prevented and the earthy constituents left in the
form of ashes.
Second. The herein described mode of employing the waste heat of the furnace
or of the gas producer for generating hot steam and for heating air for the conversion
of the fuel into gases in the producer.
Third. The herein described mode of regulating the steam supply referred to in
the preceding claims according to the chemical composition of the earthy constituents
of the fuel, and of causing the action of the furnace to produce automatically a
constant mixture of air and steam.
In Witness whereof I the said Charles Denton Abel have hereunto set my
hand and seal this Twenty-fourth day of August in the year of our Lord
One thousand eight hundred and eighty-two.
ORAR
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DRT