Improvements in Refuse-consuming Furnaces, and in the Utilization of the Products therefrom.
Year: 1894

page_text: Date of Application, 23rd Apr., 1894
Complete Specification Left, 19th Nov., 1894-Accepted, 22nd Dec., 1891
Improvements in Refuse-consuming Furnaces, and in the Utilization
of the Products therefrom.
I, RICHARD SCHNEIDER, of No. 7 Hohestrasse at Dresden in the Kingdom of
Saxony, German Empire, Engineer, do hereby declare the nature of said invention
to be as follows:-
It has heretofore not been possible to destroy or render innocuous the refuse
from houses in towns or from manufacturing premises consisting almost exclusively
of combustible materials mixed with non-combustible ones, at a small cost, nor
without having first to sort or comminute the refuse. These operations besides
increasing the expense considerably, are very apt to augment the risk of infection,
especially as regards the workmen carrying out the same.
This problem which has hitherto been unsolved, I have now succeeded in solving.
I take the raw refuse, mix it if necessary with suitable mineral substances, and
expose it to a heat sufficient to smelt its combustible components so as to form a
slag which I conduct into moulds for the manufacture of moulded bricks or stones,
or into water to make ballast material, whilst the gases produced from the
combustible refuse are added to the generator gas so as to be utilized for the
combustion and smelting process.
The furnace consists preferably of a Siemens-regenerative furnace with reversal
of flame and sloping charging shafts, and a generator plant.
The amount of slope of the charging shafts depends on the nature of the
material to be treated. A mean amount of slope suffices for the treatment of
refuse from town houses which consists on an average, in addition to water and a
small mixture of animal excrement, of about 34 to 35 % of combustible substances
such as wood, straw, paper, rags, small coal, and of 52 % of incombustible substances
such as sand, clinkers or ashes, broken earthenware, stones, lime, bones, shells etc.
Refuse from factories in which the proportion of the combustible to the
incombustible substances varies between much wider limits, will require a smaller
or greater slope according to circumstances.
In general the furnace consists of a lower, middle, and upper portion, that is to
say, in the same order, of the four regenerative chambers of a regenerative gas
furnace, of a smelting chamber, and of the charging apparatus. All these parts
are connected together in a manner suitable for the particular purpose, or, in any
known manner by means of gas or air conduits which are capable of being
regulated.
The gas generators and the larger air regenerators are connected by flues
provided with reversing valves, with the gas or air supply passages on one hand,
and on the other hand with the flue leading to the chimney, in the ordinary way.
Between each pair of gas and air regenerators there is arranged a dust-collecting
chamber. The several regenerators are each connected with the smelting chamber
by means of a number of passages varying with the size of the plant. The
smelting chamber is in this case assumed to be of that form it has in Siemens
regenerative furnace and is heated as before stated by means of regenerative firing
with reversal of flame. But a smelting furnace with water-gas firing may be
employed, ur even a smelting furnace with gas firing witbout reversal of flame.
The use of a Siemens regenerative furnace has the advantage of enabling a

page_text: maximum quantity of refuse to be melted at a minimum cost in a unit of time, and
also enables very high temperatures to be produced which are necessary when it is
desired to use only a smaller addition of mineral substances.
The smelting chamber is provided on one side with tapping holes and working
openings, and preferably has on the opposite side a large opening-which is adapted
to be closed-through which, when necessary, combustible articles of large size can
be thrown into the smelting chamber, such as for example bundles of infected linen,
furniture, carcases of animals etc. The tapping holes are so arranged and so
shaped as to allow only of the most fluid portion of the slag to be tapped.
In the ordinary course of working, the materials are charged into the furnace
through the said sloping shafts, which receive the materials through openings in
a platform above the furnace, the said openings being provided with lids or covers.
The charging shafts are connected together by a passage or tube. Branch flues
or pipes provided with valves or other closing devices, lead from this connecting
flue or pipe to both ends of the furnace, so that by this means the products of dry
distillation formed in the shafts can be led either to one or the other end of the
furnace, but always are led to that end where the heating gases and the highly
heated air are entering through the flues or pipes parting from the regenerators.
In general it may be assumed that the partly organic and partly inorganic
materials introduced into the shafts are caused by the gradual gasification of a
portion of the former to settle in the charging shafts in such a manner as to allow
of the free escape of the gaseous products and also of a gradual sliding down of
the incombustible products. However, a lateral opening may be so provided as to
allow of stoking or stirring up.
The tube establishing communication between the shafts and its branches, are
furnished with cleaning apertures, and also with devices for catching the water of
condensation. As always one or the other end of the said connecting tube or flue
is closed, whilst the other end is always in free communication with the furnace,
and as the gases in the same are drawn by the draught of the chimney into the
combustion and smelting chamber, it is impossible for gases or vapours to escape
either during the aforesaid operations or whilst fresh materials are being charged
into the furnace, but the said gases or vapours are drawn into the furnace, and
coming in contact with a current of hot air, are perfectly burnt. When the
direction of the flame in the smelting chamber is reversed by reversing the valves,
the corresponding end of the tube is closed, and the other end is opened, by
mechanism connected with said valves, as in ordinary gas furnaces.
The general process of working takes place as follows:
After the gas-generating plant appertaining to the furnace has suitably heated
the same, and a first charge of broken glass or other easily fusible material has
been smelted down in the smelting chamber, the shafts are gradually charged with
the refuse and are kept full. That portion of the organic substances which is in
the lowest part of the shafts, is burnt by the full smelting heat of the furnace so
that carbonic acid is formed which in being forced by the draught to pass through
the refuse material filling the upper parts of the shafts, causes this portion of the
material to undergo dry distillation, whereby it is reduced itself to carbonic oxide,
whilst the refuse arrives in the lower shaft portion in a coked state. Thus a
mixture consisting substantially of carbonic oxide and steam, enters at the upper
end of the shafts into the said connecting tube, and is returned back to the furnace
through said tube and its branches. On the way thither, the aqueous products are
condensed and drawn off. The materials smelted in the furnace are drawn off and
conducted into moulds, which are then gradually cooled either in an annealing
furnace or in chambers. The blocks or mould-stones thus obtained are suitable for
use as weather resisting and water resisting building material, assuming that the
composition of the whole amount of refuse agrees with the average experience. Oi
course it will be understood that the final product may be improved according to
the composition of the refuse or to the purpose in view, hy adding suitable amounts
of lime or alkali to the refuse when the latter does not contain a sufficient quantity

page_text: of said mineral substances. As the composition of refuse will vary slightly
according to the different seasons of the year, experience will very easily teach
how much of the necessary additions are requisite for the various periods of
working.
The liquid slag instead of being led into moulds, may be led into water in the
well known manner and thus become converted into small irregular pieces which
are then very suitable for use of building roads, as ballast material etc., according
to size.
Deted the 22-1 A 1901
Improvements in Refuse-consuming Furnaces, and in the Utilization
of the Products therefrom.
I, RICHARD SCHNEIDER, of No. 7 Hohestrasse Dresden in the Kingdom of
Saxony, German Empire, Engineer, 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 :-
It has heretofore not been possible to destroy or render innocuous the refuse from
houses in towns or from manufacturing premises consisting almost exclusively of
combustible materials mixed with non-combustible ones, at a small cost, nor without
having first to sort or comminute the refuse. These operations, besides increasing
the expense considerably, are very apt to augment the risk of infection, especially
as regards the workmen carrying out the same.
This problem which has hitherto been unsolved, I have now succeeded in solving.
I take the raw refuse, mix it if necessary with suitable mineral substances, and expose
it to a heat sufficient to smelt its incombustible components so as to form a slag
which I conduct into moulds for the manufacture of moulded bricks or stones, or
into water to make ballast material, whilst the gases produced from the combustible
refuse are added to the generator gas so as to be utilized for the combustion and
smelting process.
The furnace consists preferably of a Siemens-regenerative tank furnace with
reversal of flame and sloping charging shafts, and a generator plant.
The amount of slope of the charging shafts depends on the nature of the material
to be treated. A mean amount of slope suffices for the treatment of refuse from
town houses which consists on an average, in addition to water and a small mixture
of animal excrement, of about 34 to 35% of combustible substances such as wood,
straw, paper, rags, small coal, and of 52% of incombustible substances such as sand,
clinkers or ashes, broken earthenware, stones, lime, bones, shells etc. Refuse from
factories in which the proportion of the combustible to the incombustible substances
varies between much wider limits, will require a smaller or greater slope according
to circumstances.
In general the furnace consists of a lower, middle, and upper portion, that is to
say, in the same order, of the four regenerative chambers of a regenerative gas
furnace, of a smelting chamber, and of the charging apparatus. All these parts are
connected together in a manner suitable for the particular purpose, or in any
known manner by means of gas or air conduits which are capable of being
regulated.
The gas regenerators and the larger air regenerators are connected by flues
provided with reversing valves, with the gas or air supply passages on one hand,
and on the other hand with the flue leading to the chimney, in the ordinary way.
Between each pair of gas and air regenerators there is arranged a dust-collecting

page_text: chamber. The several regenerators are each connected with the smelting chamber
by means of a number of passages varying with the size of the plant. The smelting
chamber is in this case assumed to be of that form it has in Siemens regenerative
tank furnace, and is heated, as before stated, by means of regenerative firing with
reversal of flame. But a smelting furnace with water-gas firing may be employed,
or even a smelting furnace with gas firing without reversal of flame. The use of a
Siemens regenerative furnace has the advantage of enabling a maximum quantity
of refuse to be melted at a minimum cost in a unit of time, and also enables very
high temperatures to be produced which are necessary when it is desired to use
only a smaller addition of mineral substances.
The smelting chamber is provided on one side with tapping holes and working
openings, and preferably has on the opposite side a large opening-which is adapted
to be closed-through which, when necessary, combustible articles of large size can
be thrown into the smelting chamber, such as for example bundles of infected linen,
furniture, carcases of animals, etc. The tapping holes are so arranged and so shaped
as to allow only the most fluid portion of the slag to be tapped.
In the ordinary course of working, the materials are charged into the furnace.
through the said sloping shafts, which receive the materials through openings in a
platform above the furnace, the said openings being provided with lids or covers.
The charging shafts are connected together by a passage or pipe. Branch flues
or pipes provided with valves or other closing devices, lead from this connecting
flue or pipe to both ends of the furnace, so that by this means the products of dry
distillation formed in the shafts can be led either to one or the other end of the
furnace, but always are led to that end where the heating gases and the highly
heated air are entering through the flues or pipes parting from the regenerators.
In general it may be assumed that the partly organic and partly inorganic
materials introduced into the shafts are caused by the gradual gasification of a
portion of the former to settle in the charging shafts in such a manner as to allow
of the free escape of the gaseous products and also of a gradual sliding down of the
incombustible products. However, a lateral opening may be so provided as to allow
of stoking or stirring up.
The pipes establishing communication between the shafts, and its branches, are
furnished with cleaning apertures, and also with devices for catching the water of
condensation. As always one or the other end of the said connecting pipe or flue
is closed, whilst the other end is always in free communication with the furnace,
and as the gases in the same are drawn by the draught of the chimney into the
combustion and smelting chamber, it is impossible for gases or vapours to escape
either during the aforesaid operations or whilst fresh materials are being charged
into the furnace, but the said gases or vapours are drawn into the furnace, and
coming in contact with a current of hot air, are perfectly burnt. When the
direction of the flame in the smelting chamber is reversed by reversing the valves,
the corresponding end of the pipe is closed, and the other end is opened, by
mechanism connected with said valves, as in ordinary gas furnaces.
On the annexed sheet of drawings of which
Fig. 1 is a horizontal longitudinal section ou line 1-1, Figs. 2 and 3,
Fig. 2 a vertical longitudinal section on line 2-2 Fig. 1, and
Fig. 3 a transverse section on the broken line 3-3, Fig. 1,
is represented a Siemens regenerative tank furnace with reversal of flame adapted
to carry out the present invention, the communication of the furnace with the gas
producer, the latter, and the apparatus for the reversal of flame being omitted from
the drawings.
a is the smelting chamber or tank having the working openings a' and the
tapping holes a, and 6 and b' are the pairs of co-operating gas and air regenerators
having between them a dust collector and communicating with the tank a through
passages b³ and b. cand c¹ are two sloping shafts for the introduction of the
refuse, the openings through which these shafts communicate with the tank a,
and c (see Fig. 3) the upper openings of the shafts for filling in the refuse from

page_text: the platform d, the latter openings being provided with removable covers or lids e*.
At a small distance below its charging opening c³ each shaft is provided with a
gas-outlet
and these two gas-outlets are in communication with a common
discharge pipe e from the ends of which are branched off pipes e connecting
pipe with the gas-inlets opening into passages e arranged between the flues
through which the hot mixture of producer gas and air is admitted to the tank.
The said gas-outlets and -inlets as also their connecting pipes are provided with
cleaning doors e and with devices e" for removing the water condensed within the
said pipes.
Moreover, the pipes e² are provided with valves or other closing
devices not shown in the figures. Between the charging shafts c', c' is arranged
a large opening (Fig. 1) in a line with the openings for allowing large objects
to be directly charged into the tank, this opening being provided with a lid ƒ.
At the upper end of each shaft is provided an opening g for allowing of stoking or
stirring up, at all other times this opening is closed by means of a plug g'.
The general process of working takes place as follows:-
After the gas-generating plant appertaining to the furnace has suitably heated
the same, and a first charge of broken glass or other easily fusible material has
been emelted down in the smelting chamber a, the shafts c', c' are gradually charged
with the refuse and are kept full. That portion of the organic substances which
is in the lowest part of the shafts, is burnt by the full smelting heat of the furnace
so that carbonic acid is formed which in being forced by the draught to pass
through the refuse material filling the upper parts of the shafts, causes this portion
of the material to undergo dry distillation whereby it is reduced itself to carbonic
oxide, whilst the refuse arrives in the lower shaft portion in a coked state. Thus
a mixture consisting substantially of carbonic oxide and steam, enters at the upper
end of the shafts through the outlets e in the connecting pipe e', and is returned
back to the furnace through the branch pipes e, inlets and flues e. On the way
thither, the aqueous products are condensed within the pipes and drawn off. The
materials smelted in the furnace are drawn off from the tank through the tapping
holes a and conducted into moulds, which are then gradually cooled either in an
annealing furnace or in chambers. The blocks or mould-stones thus obtained are
suitable for use as weather resisting and water resisting building material, assuming
that the composition of the whole amount of refuse agrees with the average
experience. Of course it will be understood that the final product may be improved
according to the composition of the refuse or to the purpose in view, by adding
suitable amounts of lime or alkali to the refuse when the latter does not contain a
sufficient quantity of the said mineral substances. As the composition of refuse
will vary slightly according to the different seasons of the year, experience will very
easily teach how much of the necessary additions are requisite for the various periods
of working.
The liquid slag instead of being led into moulds, may be led into water in the
well known manner and thus become converted into small irregular pieces which
are then very suitable for use of building roads, as ballast material etc., according
to size.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. A process of utilising refuse from houses and manufacturing premises for the
production of gaseous fuel and artificial stones consisting in subjecting the refuse
to dry distillation, burning and smelting the residue into a liquid slag by the
combined combustion of gaseous fuel and the gases obtained from the said distilla-
tion, and transforming the slag into stones, substantially as set forth.
2. A process of utilising refuse from houses and manufacturing premises for the
production of gaseous fuel and artificial stones consisting in mixing the refuse with
fusible mineral substances, subjecting the mixture to dry distillation burning and
smelting the residue into a liquid slag by the combined combustion of gaseous fuel

page_text: and the gases obtained from the said distillation, and transforming the slag into
stones, substantially, as set forth.
3. The combination, with a regenerative tank furnace of which the tank is
provided with tapping holes, of sloping shafts for charging the tank with refuse,
gas-outlets in said shafts, and pipes connecting the said gas-outlets with gas-inlets
opening into the tank at points where the same is supplied with the mixture of
producer gas and air, as and for the purpose specified.
Dated this 19th day of November 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.