IMPROVEMENTS IN THE MEANS AND APPARATUS FOR EXPOSING SOLID SUBSTANCES TO THE ACTION OF HEAT, AND ALSO TO CHEMICAL AND ABSORPTIVE ACTION IN RELATION TO GASES, VAPOURS, AND LIQUIDS." and
Year: 1876

page_text: LETTERS PATENT to William Alexander Lyttle, of The Grove, Hammersmith,
in the County of Middlesex, Civil Engineer, and Fellow of the Chemical
Society, for the Invention of "IMPROVEMENTS IN THE MEANS AND APPARATUS
FOR EXPOSING SOLID SUBSTANCES TO THE ACTION OF HEAT, AND ALSO TO
CHEMICAL AND ABSORPTIVE ACTION IN RELATION TO GASES, VAPOURS, AND
LIQUIDS."
PROVISIONAL SPECIFICATION left by the said William Alexander Lyttle
at the Office of the Commissioners of Patents on the 1st June 1876.
WILLIAM ALEXANDER LYTTLE, of The Grove, Hammersmith, in the County of
Middlesex, Civil Engineer, and Fellow of the Chemical Society. "IMPROVEMENTS
IN THE MEANS AND APPARATUS FOR EXPOSING SOLID SUBSTANCES TO THE
ACTION OF HEAT, AND ALSO TO CHEMICAL AND ABSORPTIVE ACTION IN RELATION
TO CASES, VAPOURS, AND LIQUIDS."
This Invention consists of extended applications of the peculiar principle in
the mode of exposing solid substances to heat by means of the apparatus designated
the "hollow wall" in the Specification of iny Letters Patent, No. 3579, dated
15th October 1875, and entitled "Improvements in the Means and Apparatus for
Deoxidating Metallic Ores, Oxides, and Sulphates, which Improvements are Equally
Applicable to the Coking, Charring, and Destructive Distillation of Solid Organic
Matter, to the Calcining of Metallic Ores, and to the Production of Carbonic
Oxide Flame."
The extended applications of the said hollow wall apparatus are as follows:-
The hollow wall constructed with openwork sides in any of the various ways
described in the aforesaid Patent, No. 3579, and of any suitable material, will act
in its new use as a partition or diaphragm across a tank or closed chamber through
which the liquid gas or vapour under treatment shall be forced or drawn. Any
number of such hollow walls may be placed as a series in one tank or chamber to
augment the filtering or other required action of the material with which the
hollow wall may be charged.
When a liquid is filtered or passed through the charcoal or other material in the
hollow wall that material may be discharged periodically by means of a trap, slide,
Price Sdl

page_text: or other valve at the bottom of each hollow wall in one end, or at any other
point in or near the bottom. By opening this valve the escaping liquid will
Hush out the whole of the contents of the hollow wall, which may be run into
a settling tank from which the liquid and the discharged solid matter may be
conveniently removed.
A jet of water or any other liquid of a suitable nature thrown into the hollow
wall by means of a hose pipe will remove obstructions and accelerate the discharge,
and so also will a chain hung inside the hollow wall and used as ordered in the
Specification of the aforesaid Letters Patent.
When gases are passed through this hollow wall arrangement in a closed chamber
or tunnel for filtration or absorption, as herein-after described, the hollow wall
must be charged with its required contents from the top outside the tunnel or
chamber, and kept closed air-tight, so that the gases or vapours under treatment
may have no escape, except by passing through the material contained in the
hollow wall. The movement of liquids, gases, or vapours through this application
of the hollow wall may be accelerated by any apparatus for creating a current
under pressure, whether by forcing or by suction. When liquids are passed through
for filtration or otherwise the necessary flow of the current may be maintained by
gravitation only.
•
The discharging arrangement sealed with water or other suitable liquid, described
in roference to Figures 7 and 8 in the Specification of the aforesaid Patent, will
answer well for the purpose of discharging the contents of the hollow wall readily
in most of the applications herein referred to, but all the other discharging arrange-
ments described in the said Patent are also available.
This application of the hollow wall is suitable for the production of sulphate of
sodium by filling the hollow wall with chloride of sodium, pure or intermixed
with insoluble matter, as herein-after described, and passing through it the current
of sulphurous acid gas, steam, and air, or else the vapour of sulphuric acid which
is needed to decompose the chloride of sodium and form the required sulphate.
The escaping hydrochloric acid gas may be passed through another closed chamber
with similar hollow wall partitions, and thus be made to combine wholly with lime,
metallic ore, or any other substance with which it may be required to combine, such
substance being contained in the hollow wall.
The hollow wall thus arranged as a partition across a closed chamber or tunnel
may be filled with coke or other insoluble substance in fragments, kept moist by
water or any other suitable liquid, and it will thus act the part of a gas scrubber
to intercept and condense hydrochloric or any other gas or vapour. In this way
the hollow wall will answer for the purposes of a scrubber and purifyer of coal or
other hydrocarbon gas or any gas or vapour requiring purification or absorption.
In making sulphuric acid the same arrangement of hollow wall scrubber may be
employed, the coke or other lump material used in the hollow wall being kept wit
by the water or dilute sulphuric acid by which the sulphuric acid vapour made in
the usual or any other way may be absorbed. The latter arrangement will also
answer for making sulphate of sodium by causing a strong brine of chloride of
sodium to percolate down through the lumps of coke, vitrified carthenware, or other
insoluble material in the hollow wall. The liquid after passing down through the
hollow wall once may be sent through the apparatus a second time if not thoroughly
converted into sulphate of sodium. The solution of chloride of sodium must not be
made so strong as to cause the choking of the hollow wall by crystals of the
sulphate of sodium. Liquid of any kind thus made to percolate downward through
the hollow wall may be allowed to escape at the bottom through a syphon tube
which will keep back the gases.
When chloride of sodium in crystals is charged into the hollow wall for exposure
to the action of sulphuric acid vapour as aforesaid, it will tend to prevent "scaffold-
ing" or choking of the resulting sulphate of sodium in the hollow wall if the
charge of chloride of sodium is first thoroughly dried or is plentifully mixed with
small cubes or irregular fragments of broken slag or other heavy insoluble substance.

page_text: These fragments will not only facilitate the permeation of the acid gas, but will
also by their weight crush down the contents and prevent choking. The insoluble
fragments can be subsequently separated for further use by screcuing or by
dissolving the resulting salt.
Carbonate of sodium can be readily converted into bicarbonate by charging the
hollow wall with the carbonate, and causing a current of carbonic anhydride to pass
through the hollow wall in the manner aforesaid till the required change is effected.
Atmospheric air, the oxygen of which has been turned into carbonic anhydride,
by the combustion of coke or charcoal will answer for this purpose.
In carrying this Invention into effect as a means of rapid and economical filtra-
tion, both for the drinking water of towns and for the effluent water of town
sewage, and also generally, I employ as my special filtering agent a mixture of
intimately incorporated carbonaceous matter, preferably peat, charcoal, and reduced
iron, made by incorporating powdered iron ore or ferric oxide with plastic pont,
drying, and then subjecting the mass to the heat of a deoxidating flame till the
oxide of iron is reduced. This reduction can be effected with the greatest cheapness
and speed by means of the hollow wall in its metallurgical applications to which
the aforesaid Letters Patent of 15 October, 1875, refer.
The filtering character of this ferruginous charcoal may be modified to suit
various liquids by blending with the plastic peat and iron ore or oxide any desired
proportions of lime or clay, or both together. The admixture at the same time
with the wet ingredients of a small quantity of gelatinous inatter or size made
by boiling down animal waste from slaughter houses, or fish waste, will impart
cohesiveness to the resulting ferruginous charcoal, and thus make it possible to
obtain in a more granular or lumpy form.
The following statement relating to the manufacture of alkali illustrates one of
the many ways in which this present Invention and my previous Letters Patent
aforesaid of 15th October last may be worked together with great combined econo-
mical effect.
Let a hollow wall be erected with openwork sides precisely as ordered in the
aforesaid Patent, the height of this hollow wall and the number as well as length
of the lateral shelves described in the Specification of the aforesaid Patent for
giving a long zig-zag run to the flame gases being made as great as may be con-
veniently possible. This hollow wall I shall call the "decomposer." Alongsido
this "decomposer" creet a similar but smaller hollow wall, in which pyrites or
"blende" inay be calcined or burned so as to produce sulphurous acid in the
manner prescribed in the aforesaid Patent. The latter hollow wall I shall call the
gas wall,"
46
At one side of the hollow wall of the "decomposer" there may be provided
furnaces for the purpose of imparting such heat as may be found needful in order
to accelerate the following reaction in the perfectly dried crystals or lumps of chlo-
At the other or oppo-
ride of sodium which forms the charge of this hollow wall.
site side of the hollow wall of the decomposer the sulphurous acid enters from the
adjacent gas wall in admixture with steam and atinospheric air in such proportions
as are now found most convenient, and also, but not indispensably, with a small
admixture of nitric acid vapour. The presence of a very small percentage of nitric
acid in the mixture of sulphurous acid, air, and steam greatly accelerates the con-
version of the chloride of sodium into sulphate of sodium.
The heating or furnace side of the decomposer may be built either of solid
vertical fire tiles, as shown in Figures 2 and 13 of the Specification of the aforesaid
Letters Patent, or of cranked fire-bricks, as shewn in reference to Figure 16 of the
same Patent. The cranked bricks are the best materials with which to construct
the sides of the hollow wall for all the purposes of this Invention, but it will be
better to mould the cranked bricks with an inclined or cranked end and horizontal
body, as shewn at P, Figure 16, of the Specification of the aforesaid Patent. The
horizontal portions of the cranked brick under the latter modification will rest
upon
each other so as to form a more strong and stable wall, but the diverting

page_text: shelf P in the said Figure 16 must in that case be made long enough to provide
the necessary space for the circulation of gases between the outside of the hollow
wall and the containing solid brick walls in which the diverting shelves are set.
Figure 15 in the Drawings of the aforesaid Patent shews a side elevation of part
of a hollow wall thus built with cranked bricks, so laid as to afford open spaces
through which gas can enter or escape, whilst the overlapping inclined ends of the
cranked bricks prevent the escape of the contents of the hollow wall.
The same arrangement of hollow wall, as shewn in reference to Figures 1 and 2
of the aforesaid Patent Specification, but built of cranked bricks as aforesaid, will
answer as a rapid and continuous drier of chloride of sodium for the production of
sulphate of sodium in the aforesaid or any other manner in which the dry sult is
needed. In order to prevent choking of the hollow wall by the salt whilst the
drying is taking place it is well to compound the drying charge of a mixture of
perfectly dried and undried salt. By this means one half or more of the discharged
and perfectly dried contents of the hollow wall will be available for treatment in
making sodic sulphate as aforesaid whilst the remainder of the salt discharged
will be mixed with undried salt and again charged into the top of the hollow wall.
Having obtained sodic sulphate as herein-before stated, this salt may be con-
verted into black ash and caustic soda in the ordinary way, or the solution of the
sodic sulphate may be directly decomposed into that of caustic soda or carbonate
of soda by precipitation with baric oxide or carbonate made by the use of the
hollow wall as prescribed in the Specification of the aforesaid Letters Patent. For
this purpose baric sulphate in fine powder, preferably the precipitated sulphate, is
intimately mixed in a dry state with finely powdered carbonaceous matter and
charged into the hollow wall constructed for reduction or deoxidation only as
described in the Specification of the aforesaid Patent. The baric sulphate thus
intermixed with carbon and exposed to reducing heat is converted into baric sul-
phide as a continuous operation, and this resulting sulphide may be converted into
carbonate or hydrate of baryta in any of the well-known ways. Without describing
these various known methods I would state that by boiling the baric sulphide with
oxide of zinc the latter readily becomes precipitated as "blende," or sulphide of zinc,
and hydrated oxide of barium remains in solution. By adding this hydrate of
baryta in proper proportion to sodic sulphate, the baryta is precipitated as baric
sulphate, and the supernatant liquid is chemically pure caustic soda needing no
further treatment except evaporation. The precipitated baric sulphate is again
reduced to sulphide in the hollow wall as aforesaid, and again gives up its sulphur
to oxide of zinc. The latter then becomes the source of the sulphurous acid
required in making sodic sulphate as aforesaid by calcination or burning in the gus
wall, as already described. Oxide of zinc is again the result, and so on, the chemical
reactions may be worked in a circle.
When baric sulphide in solution is allowed to percolate down through a hollow
wall gas scrubber as aforesaid, subject to exposure to carbonic anhydride, the
result will be precipitated baric carbonate. A dried but infused mixture of barie
carbonate and precipitated sulphur is easily separated by allowing the mixed
powders to fall in a thin sheet or curtain in front of a well distributed and very
imoderate draft or blast of air. Owing to the circumstance that baric sulphate is of
so much greater density than sulphur the latter is thus separated with ease by
being blown to a greater distance.
When the hollow wall is made to act as a filter, by holding as a vertical screen
any desired filtering material, the sides of the hollow wall must always in that case
be made of open work "louvres" by being constructed of cranked bricks or other-
wise as described herein-before and in the aforesaid Letters Patent. The liquid
vapour or gas under treatment may either be passed transversely through the
hollow wall sides in the tank or tunnel, already referred to, or they may be made
to circulate upward outside the hollow wall by incans of the arrangement of lateral
diverting shelves described in the aforesaid Specification of my Letters Patent
dated 15th October, 1875, for distributing the heating flame.

page_text: The extended application of the hollow wall principle of the aforesaid Letters
Patent to the exposure of solid matters to heat is chiefly as the means of melting
any solid matter requiring fusion, especially metals, whether in a powdered or
massive condition. Smelting of metallic ores may be conducted by this means
with fusion of the resulting metals and slag by making the sides of the hollow wall
of fire tiles or cranked bricks as described, and charging it with crushed ore or
metallic oxide mixed with the necessary fluxing ingredients crushed or in a
powdered state. Powdered carbonaceous matter may or may not be intermixed
with the ore and fluxes, to effect wholly or assist the reduction of the metal by a
deoxidating flame as described in the aforesaid Letters Patent, no lumping of the
materials being necessary under this extended use of the said Invention.
The diverting shelves described in the Specification of the said Letters Patent
may also be wholly dispensed with, the flame being allowed to ascend directly up
the sides of the hollow wall.
The hollow wall is also available for every use of every kind to which the
drying action of a kiln floor is now applied, and furnishes a quick and economical
means of drying malt and all other grain. It will also serve as the means of
heating, drying, roasting, or charring all solid substancos requiring such treatment.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Alexander Lyttle in the Great Seal Patent Office on the
20th November 1876.
WILLIAM ALEXANDER LYTTLE, of The Grove, Hammersmith, in the County of
Middlesex, Civil Engineer, and Fellow of the Chemical Society. "IMPROVEMENTS
IN THE MEANS AND APPARATUS FOR EXPOSING SOLID SUBSTANCES TO THE
ACTION OF HEAT, AND ALSO TO CHEMICAL AND ABSORPTIVE ACTION IN RELATION
TO GASES, VAPOURS, AND LIQUIDS."
The object of this Invention is to extend the application of the peculiar principle
in the mode of exposing solid substances to licat by means of the apparatus
designated the hollow wall in the Specification of my Letters Patent, numbered
3579, dated 15th October 1875, and entitled "Improvements in the Means and
Apparatus for Deoxidating Metallic Ores, Oxides, and Sulphates, which Improvements
are Equally Applicable to the Coking, Charring, and Destructive Distillation of Solid
Organic Matter to the Calcining of Metallic Ores, and to the Production of Carbonic
Oxide Flame." The extended applications of the said hollow wall principle are as
follows:-The hollow wall constructed with openwork sides in any of the various
ways described in the aforesaid Patent, No. 3579, and of any suitable material will act
in its new use as a partition or diaphragm across a tank or closed chamber through
which the liquid, gas, or vapour under treatment shall be forced or drawn. Any
number of such hollow walls may be placed as a sories in one tank or chamber to
augment the filtering or other required action of the material with which the
hollow wall may be charged.
When a liquid is filtered or passed through the charcoal or other material in the
hollow wall that material inay be discharged periodically by means of a trap, slide,
or other valve at the bottom of each hollow wall, as at B, Figure 9), or at any other
point in or near the bottom. By opening this valve the escaping liquid will flush
out the whole of the contents of the hollow wall, which may be run into a settling
tank from which the liquid and the discharged solid matter may be conveniently
removed. A jet of water or any other suitable liquid thrown into the hollow wall
by means of a hose pipe will reinove obstructions and accelerate the discharge, and
so also will a chain hung inside the hollow wall and used as herein-after described

page_text: for a like purpose. When gases are passed through this hollow wall arrangement
in a closed chamber or tunnel for filtration or absorption, as herein-after described,
the hollow wall must be charged with its required contents from the top outside the
tunnel or chamber, and kept closed air-tight so that the gases or vapours under
treatment may have no escape, except by passing through the material containel
in the hollow wall. The movement of liquids, gases, or vapours through this
application of the hollow wall may be accelerated by any apparatus for creating a
current under pressure, whether by forcing or by suction. When liquids are passed
through for filtration or otherwise the necessary flow of the current may be main-
tained by gravitation only.
The discharging arrangement sealed with water or other suitable liquid, as
described with reference to Figures 7 and 8 in the Specification of the aforesaid
Patent, will answer well for the purpose of discharging the contents of the hollow
wall under some of the applications herein described. The hollow wall constructed
with open jointed fire-block sides, or with sides made of cranked bricks, as described
in reference to Figure 2 of the accompanying Drawings, will answer well as the
means by which to expose large quantities of chloride of sodium to the action of
the necessary gases in order to produce sodic sulphate. The escaping hydrochloric
acid may be intercepted by a hollow wall scrubber filled either with lump coke
moistened with a falling shower of water, or filled with iron ore or any other solid
matter with which the hydrochloric acid is intended to combine.
The following is the method of employing the hollow wall for the production of sodic
sulphate-Chlorido of sodium in a crushed state or in crystals is mixed with any in-
soluble matter in the form of hard nuggets, such as flint, gravel, or crushed slag, 'for the
purpose of rendering the salt more open to the permecation of gas, and this mixture,
with or without the provious drying of the salt, is charged into the hollow
wall A, F, V, of the apparatus, shown at Figure 7 in vertical cross section. Air and
steam are then admitted under suitable pressure by the pipe P and sulphurous neid
gas by the pipe Z, a small percentage of nitric acid vapour being also admitted,
if desired, through the pipe N. The nitric and sulphurous acids must both be
supplied under such pressure as will ensure their passing in admixture with the
air from the gas chamber L, P, N, through the above-mentioned salt mixture in the
hollow wall A into the space which intervenes between the hollow wall A, F, V, and
the solid back wall R, C, and thence back through the hollow wall to the similar
gas space shown between F and X, with final egress through the pipe B, E.
During the passage of the sulphurous acid gas, air, and steam, with nitric acid if
desired, the chloride of sodium is decomposed, and sodic sulphate with hydrochloric
acid are at the same time produced. The sodic sulphate is periodically withdrawn
from the open arch W, T, V, thus causing a corresponding subsidence of the con-
tents of the hollow wall, and this subsidence is net by a corresponding fresh charge
of chloride of sodium into the top of the hollow wall at A. When the latter salt
is thoroughly dried it is not always necessary to intermix it with gravel or other
insoluble lumpy matter.
The arrangement of hollow wall, shown in reference to Figures 1 and 2 of the
aforesaid Patent Specification, No. 3579, and Figures 1 and 2 of the accompanying
Drawings, will answer as a rapid and continuous drier of chloride of sodium, but
no cooler at the bottom of the hollow wall will in that caso be required, the dried
salt being discharged in a hot state. In order to prevent caking of the salt whilst
the drying is taking place, it may either be mixed with gravel as aforesaid, or with
about one half its weight of previously dried salt.
The arrangement shown in Figure 7 will also answer for the conversion of sodic
aurbonate into bicarbonate, the sodic chloride being replaced by sodic carbonate,
and the sulphurous acid gas, air, and steam being replaced by a mixture of carbonic
anhydride and nitrogen obtained by burning coke, charcoal, or carbonic oxide with
a sufficient supply of air to ensure perfect combustion.
The apparatus shown in Figure 7 will also answer perfectly as a pyrites burner

page_text: for the production of sulphurous acid gas required as above, or for any other
purpose. In that case the hollow wall A, F, V, is filled with broken pyrites, which
is oxidated by means of a blast of hot or cold air together with steam forced
through it from the chamber L, P, N, as already described in relation to the pro-
duction of sodic sulphate, the sulphurous acid gas and nitrogen being given off*
through the pipe B, E.
The same apparatus, Figure 7, will answer without any modification for the
conversion of baric sulphide into baric carbonate, the hollow wall being filled with
lumps of coke, through which a blast of carbonic anhydride and nitrogen is forced
from the chamber L, P, N, as already described in relation to sodic bicarbonate, a
shower of baric sulphide in solution being made to fall down at the same time
through the lumps of coke or other hard lump material in the hollow wall. The
mixture of baric carbonate and sulphur thus obtained from the bottom of the
hollow wall may when dry be readily separated by means of a common winnowing
machine into its separate component parts, if the winnowing blast is properly used,
because of the greater specific gravity of the baric carbonate as compared with that
of precipitated sulphur.
The accompanying Figures 1 and 2 represent the deoxidating and heating or
charring hollow wall apparatus described in the aforesaid Specification of my
Patent, No. 3579, with several improvements in the working details which are well
calculated to increase its efficiency. Figure 1 is a sectional side view and Figure 2
a sectional end view of the same apparatus.
A, F, C, is the hollow wall constructed of cranked bricks or of common fire-
bricks laid with dry or open joints, F, C, being the cast-iron frame from which
the sheet-iron cooler F, C, 13, is hung between two sets of of diverting shelves 1, 2, 3,
projecting from the brick wall 1, 12, these shelves being for the purpose of giving
a long run, zig-zag from side to side, to the coll air drawn up by the exhausting
port of the blowing apparatus employed to force air through the red-hot coke in
the bottom of the coke chamber R, N, T. These diverting shelves are fully
described in the aforesaid Specification of Patent, No. 3579. All the other details
of this form of the hollow wall apparatus are similar to those described in the said
Specification, excepting the following important mode of facilitating the removal of
ash and clinker from the bottom of the coke chamber without requiring the stoppage
of the blast.
The furnace floor is in the line of Z, N, Z, Figure 2, and of Y, Y, Figure 1, but
the fuel chambers R, N, T, and S, N, T, Figure 2, descend to a lower or ash-floor at
V, where access is obtained to their contents through the open archies W, T, V,
Figures 1 and 2. The lower part of these fuel chambers will be filled with ash and
clinker in the course of working, and will thus serve to seal the bottoms against
the escape of gas or blast from above. When this ash is periodically shovelled
away by a man standing on the ash-floor V the fuel in the fuel chamber R, N, T,
Figure 2, sinks down, and by this means a clean and free body of red-hot fuel is
maintained easily for the blast from Y, Figure 2, which passes through the open-
work brick arches L', Y, L, N, Figure 2, and impinges upon the hollow wall,
passing up (without the use of flame-diverting shelves in the case shown in the
Drawing) to D, B, where it escapes by any convenient end flue.
Figure 12 shows on a larger scale a portion of the bottom of the hollow wall
arrangement represented in Figure 2. In Figure 12, F, F', represents the hollow
wall built of cranked bricks, the two parallel walls of which are kept asunder by
means of the flat heart-shaped plate of fire-clay set between them at short intervals
horizontally and vertically. These heart shaped distance plates are made of such
thickness as will admit of their being placed between the cranked bricks which are
set with open joints. Six of these cranked bricks set thus are shown between A
and B, Figure 14.
The blocks B, B¹, Figure 12, prevent any outward displacement of the cranked
bricks being built into the solid wall M and L, Figure 2, from which they project
at such intervals as will not obstruct the run of the flame gases upward. D,

page_text: Figure 12, represents the coke in the coke chamber under consumption by a blast
of air from P passing to the flame space F¹, B¹, as shown by the arrows.
From A to D, B, Figure 2, is a hopper at the top of the hollow wall, and by
means of this addition the coke chambers R, N, T, S, N, T, can be carried to a
greater height. A chain or a horizontal bar hung by the two ends from above the
top of the hopper A, D, B, should be provided as the means for preventing any
choking of the material under treatment. The chain or bar should hang along
the bottom of the hopper, and may be connected at the ends with a pulley arrange-
ment overhead, by means of which it can be forcibly jerked or lifted upwards in
order to remove or detach obstructions.
Figure 3 shows precisely the same arrangement of hollow wall with side fuel
chamber, but without any sheet-iron cooling apparatus, the bottom of the hollow
wall in this case being formed as a well to receive molten metal. The hollow wall
of this melter terminates upon flat fire-clay slabs at X which prevent the metal
under fusion from falling into the well C; but the metal which becomes fluid in this
hollow wall arrangement is free to run out through its sides, leaving the unimelted
metal behind, and passes down into the well C by openings outside the bottom of
the hollow wall at X, X. Any metal such as bars of blister steel can be lowered
vertically into this melter and melted down as successfully as in a crucible. Jets
of air may be thrown into the flame space which intervenes between the inner
wall B, L, of the fuel chambers R, N, S, N, and the outer face of the cranked bricks
which form in the Drawing the hollow wall of the melter. Greatly increased
intensity of heat is thus obtained by burning the carbonic oxide of the flame into
carbonic anhydride, but when oxydation of the metal is liable to occur, no such com-
bustion of the carbonic oxide can be allowed.
Figure 4 is a sectional side view of this melting apparatus when constructed on a
very small scale of length. This melter answers well for fusing into cast steel a
mixture of reduced iron and carbon or powdered reduced iron, known as spongy
iron," which has undergone the process of "cementation" into steel by exposure to
hent with intermixed carbon.
Figure 13 shows on a larger scale an end sectional view of the bottom of this
melter, and Figure 14 shows a side sectional view of Figure 13. B, R, and B, R, are
the two walls of open jointed fire blocks filling arches at the bottom of the fuel
chambers of the melter, as shown at L, N, Figures 2 and 3, through which the flanne
from the fuel passes into the flame space F, as described in reference to Figure 2.
The hollow wall of the melter nced not necessarily be built of cranked bricks, fire-
bricks or blocks laid with open joints or without fire-clay cement being equally
available for every application of the hollow wall principle, in which the material
under treatinent is not liable like animal charcoal to run out through the open
joints of the rectangular bricks or blocks. The well for receiving the molten metal
is shown at W, Figures 13 and 14, with a tap hole L, L', Figure 14. D, T, is the
bottom slab of fire-clay upon which are built the solid close jointed or open jointed
walls S, T, and S, L, Figure 13, and B, M, N, Figure 14. Upon the tops of these
bottom portions of the hollow wall are erected the cranked brick sides when such
bricks are thought necessary. The solid walls S, T, and S, L, Figure 13, may be
replaced by cranked bricks or open jointed blocks of fire-clay, but in any case they
rest each upon a row of fire blocks V, P, Figure 14, laid with openings M, N,
between the blocks through which the molten metal can flow out of the hollow wall
above the bottom slabs D, T, Figures 13 and 14, and run into the well W, through
similar openings S, R, left between the blocks upon which the bottom slabs D, T, are
laid. R, T, and R, L, Figure 13, are a row of fire-clay slabs which close the bottom of
the flame space F immediately above the metal vents, M, N, Figure 14. By this
meaus ash cannot fall into and choke the well W through the spaces D and T,
Figure 13. K, K, are tubular trying holes dipping into the well W, Figure 14.
The reducing or deoxidating apparatus, shown in Figures 1 and 2, is suitable for
smelting zinc ores, but it does not in that case need to have any cooling arrangement
attached to the bottom through which the waste gangue of the ore is drawu off

page_text: unless when the smelting of zinc and the deoxidation of iron ore are carried on at
the same time by intermixing the two ores or oxides in a crushed state with
powdered coke, anthracite, or charcoal. In that caso the reduced iron is drawn off
through the cooler, as described in the Specification of the aforesaid Patent,
No. 3579. In order to give ready egress to the volatilized zinc, the flue for the
escaping flame gases should not be placed so high as to reduce the temperature of
such gases below that at which zinc is volatilized. When this course, however, is
not deemed desirable the zinc is deposited in the upper part of the flame space
which intervenes between the outside of the hollow wall and the solid containing
walls S, L¹, R, L', Figure 2. On accumulating there it falls down to the bottom
of the flame space, which must accordingly be constructed as a channel or well
to receive and carry off the zinc which is remelted there by the greater heat. This
channel or well may be constructed as shown at W, Figures 13 and 14. In
dooxidating or smelting zinc ore or the oxide or sulphate of any other highly
oxidizable metal, the apparatus shown in Figures 1 and 2 may be constructed with
a double set of parallel fuel chambers on each side, the outer screen or wall of fuel
in the outer chamber of each pair being only for the production of heat by com-
bustion of fuel, and the inner parallel wall of fuel intervening between the outer
fuel chamber and the hollow wall being exclusively required to intercept the passage
of free oxygen and carbonic anhydride. The bottom of this intercepting fuel
chainber should open either into the ash-floor at V, or should be carried to a similar
ash-floor lower down. This intercepting screen of fuel should consist of clean
well broken coke, anthracite, or charcoal.
Figures 5 and 6 relate to another application of the same new principle in the
mode of exposing solid matter to heat and gascous action, the object in this case
being the conversion of all the carbon of solid fuel into fuel gas. Figure 5 shews a
sectional side view, and Figure 6 a sectional end view of the same apparatus. In
this case the hollow wall is shown as built of common fire-brick, laid with open
or uncemented joints whero flame and gases are intended to pass, and there is no
fuel chamber, because the fuel which fills this hollow wall is wholly consumed
between L and N, Figure 6, by the blast which is forced through it from the blast
pipe Y. This blast passes through the open joints of the fire blocks which fill the
arch L, N, Figure 6, and through the fuel in the hollow wall A, L, N. The mixture
of red hot carbonic oxide and nitrogen thus produced enters the flame space which
is provided between F, X, of this hollow wall, and the outer solid back wall F, K, S,
of the apparatus. The flame gases have no egress thence except upward through
the open joints of the bricks forming the back wall F, L, of this form of hollow wall,
and through the fuel contained in this upper part of it. The hot fuel gases thus
give up their heat to the fuel by direct permeation, and distil from it all volatilizable
matter, passing off through the open joints of the bricks which form the front of the
hollow wall between B and R. The gaseous mixture then consists chiefly of
carbonic oxide, hydrocarbon gases, and vapours, together with atmospheric nitrogen,
and escapes through the gas space B, R, into the pipe B, E, and hydraulic main M.
The bottom pipe R, M, is to carry off any tarry matter which may have become
condensed in the gas space B, R. The gas space and flame space means in every
part of this Specification a space parallel with and of equal arca to that of the
hollow wall, such space being between the outside of the hollow wall and the
adjacent parallel solid or containing wall.
The hydraulic main M should lead to the present ordinary means for distributing
illuminating gas to the points of its consumption.
In order to facilitate the fall of the fuel in this hollow wall one or both of its
side walls may be built with a taper, widening the capacity downwards, as is shown
in the wall F, L, Figure 6, the taper being imparted by means of a series of receding
arches, 1 to 5, as shown in Figure 5, or by any other convenient method of building.
In order to prevent the caking of the fuel when highly bituminous coal is employed,
it is desirable to break up the vertical passage in the flame space at the back of this
hollow wall between F and L by means of diverting shelves, shown at A, B, and C,

page_text: in Figures 15 and 16. Figure 15 shows a side sectional view of these shelves, the
zig-zag course of the flame gases being indicated by the arrows. By this means
the largest proportion of the flame gases and heat will pass through the fuel in the
hollow wall below the shelf A; and a further proportion of the gases at a lower
temperature from loss of heat by radiation in transit will go through the charge of
the hollow wall between the shelves A and B. A further but small proportion of
these gases, at a still more reduced temperature from the slightly extended operation
of the same cause last stated, will pass through the hollow wall between B and C,
and so on according to the number of the diverting shelves provided. The bitumi-
nous coal contained in the hopper A, F, B, will thus be subjected to a very moderate
heat on entering the hollow wall proper below F, B, with a steady increase of
temperature and loss of volatilizable matter as it sinks downward until it reaches L,
when it has thus become coke gradually without the fusion and glueing together of
the mass.
The latter condition is also secured by mixing ash or cinders with the
bituminous coal in order to deprive it of its caking property. When steam is
admitted into the blast chamber P, Figure (i, in such quantity as will not check the
combustion of the residual coke between L and N, the water is decomposed into
carbonic oxide and hydrogen, and thus augments the yield of fuel gas. When the
whole of the coke thus produced in this application of the hollow wall is consumed
at L, N, to produce carbonic oxide, nothing but ash and clinkers will remain to be
withdrawn periodically from the discharging arch W, T, V; but if gas for illumina-
ting purposes should be required with the use of this apparatus, instead of that
herein-after described, it will be necessary to consume no more coke at L, N, than
is needful for the distillation of the coal or other fuel in the upper part of the hollow
wall. It may in that case be found desirable to substitute for the discharging
arch W, T, V, Figure 6, the water sealed discharging bottom prescribed for the
hollow wall arrangement in reference to Figures 18 and 20.
In all applications of this open-jointed hollow wall principle in which it is not
necessary to ensure absolute security against oxidation of the inatter under treat-
ment, a steam blast on the well-known locomotive chimney principle may be
employed as the means both of forcing in the air for the combustion of fuel and of
producing fuel gas by the above-mentioned decomposition of steam. Any blowing
or exhausting arrangement, drawing or forcing air from the blast chamber, as
herein-before described, may be employed wherever a blast is herein referred to.
Figure 8 represents a sectional side view of a filtering apparatus on the hollow
wall principle. Six hollow walls, numbered at the tops from 1 to 6, and made of
timber, arranged in Venetian blind fashion, are shown as fixed partitions dividing
the tank A, B, V₁, V, into six compartments having no communication with each
other except through these hollow walls which will be filled with the required
filtering material. Water-tight partitions with valves VI, V, also divide the tank
into three compartments with two hollow walls in each. These valves must be
open when filtration begins, and the liquid to be purified runs from the spout A
through all the hollow wall filtering screens and out at the pipe R'. This working
of the apparatus goes on until the filtering matter in the hollow walls, Nos. 1 and 2,
is exhausted, when the supply of liquid is stopped at the spout A, and the walls 1
and 2 are discharged as herein-before described. These walls are then charged with
fresh filtering inatter, but the flow of the liquid under treatment is reversed, the
inlet being from the spout B and the outlet from the pipe R. By this means the
contents of the hollow walls 5 and 6 become wholly exhausted also, when they are
similarly discharged and refilled with a reversal back to A and R¹ of inlet and
outlet of the liquid. In due time the two middle hollow walls 3 and 4 also require
discharge and refilling; but by this means there are secured speed of filtering
action, with total utilization of the whole of the filtering matter, and great facility
for partial renewal as exhausted.
Figures 10 and 11 relate to an apparatus combining the functions of the reducer
or the melter described with reference to Figures 1 and 2 or 3 and 4, and those of
the fuel gas generator described with reference to Figures 5 and 6.
The only

page_text: difference between this application of the hollow wall principle and that shown in
Figures 1, 2, 3, and 4 is that the fuel chambers R¹, N, and S, N, are built with
bricks lined with open joints on both sides between R and B, F, no egress being
provided for the flame gases after passing up the outside of the hollow wall A of
the reducing apparatus, Figure 10, except through the open-jointed bricks and fuel
of the fuel chambers R¹, T, and S, T, between R and B, F. The front side of the
fuel chamber between R and F is tapered by a succession of arches 1 to 4,
Figure 11, in the same way as the back wall F, L, of the hollow wall in Figure 6.
On passing through the open joints of this tapered side the flame gases, taking
with them the volatilizable matter of the fuel in the fuel chamber R¹, R, L,
pass off into the hydraulic main at M, the pipe connexions at B, E, M, R, being
for the same purpose as I have described in reference to Figures 5 and 6. By the
use of this combination bituminous coal, instead of coke, can be employed as the
means of providing the needful reducing heat for effecting deoxidation of the
mixture of ore or other material and carbon in the hollow wall A, because such
coal is converted into coke on sinking down froin B, F, to R by the passage of the
flame gases as above described; and its combustion between L and N into carbonic
oxide provides the reducing heat free of cost through the production, as a secondary
result, of a large volume of fuel gas, varying from one hundred and twenty to two
hundred thousand cubic feet out of each ton of coal thus consumed. This gas has
a high calorific value.
Figures 18, 19, 20, and 21 refer to one of the most important of the various
methods in which my said Invention of the hollow wall may be made the
economical means of exposing solid matter in lumps or nuggets to the action of
heat and flame gases, namely, the production of illuminating gas.
Figures 18, 19, and 20 refer to the same apparatus; Figure 18 being an end
sectional view, and Figure 19 shewing two sectional side views of Figure 18 drawn
in lines of section of Figure 18, which are stated on each; Figure 20 shews a side
elevation viewed from H, Figure 18.
B, Figure 18, represents a coke chamber constructed and worked precisely as
already described in reference to Figures 1 and 2, the object being to produce
heat and carbonic oxide intermixed with nitrogen by means of a blast of air pro-
pelled or exhausted through the open jointed fire blocks filling the arches 9 and 14.
A, Figure 18, is the distillery hollow wall, and is filled with coke at the coni-
mencement of working from the bottom of the discharging tank H, Z', S, Figure 18,
to the top of the open jointed arches 13, 10, the upper portion from 13 to A being
filled with bituminous or gassy fuel as a hopper to feed the lower portion under
13 and 10. The coke discharging tank H, Z, S, is filled with water up to such
level G as will serve to keep the bottom of the distilling chamber A sealed against
the escape of gas from its bottom at G. By means of a pipe P a blast of nir is
supplied which enters the blast chamber M, 5, and has no egress except as shown
by the arrow through the ignited coke in chamber B, and also through the
contents of the distilling chamber A into the gas chamber N, 2, whence it passes
off as a mixture of hydrocarbon gas, carbonic oxide, and nitrogen, with the usual
condensible vapours obtained in distilling coal, through the pipes N, L, Figures
18 and 20.
When this apparatus has become fully heated coke is withdrawn from the tank
H, Z, S, by means of a rake, hoe, or the dredger apparatus herein-after described,
and a corresponding fall in the higher contents of the distilling chamber takes
place, thus causing a portion of the heated bituminous coal to come down between
the upper parts of the open-jointed arches or walls 13 to 4, and 10 to 6, Figure 18.
By this gradual depression of the contents the slowly descending coal is specdily
robbed of all its volatilizable matter by the direct impact of the permeating blast
of red hot carbonic oxide and nitrogen which flows constantly through the whole
area of the arch 13 to 4. A partial distillation without fusion thus commences
at 13 and is thoroughly completed when the fuel reaches 4. In this way the
combustion of a very small quantity of coke in the chamber B is sufficient to

page_text: expel all the volatilizable matter from a large quantity of bituminous or gassy
fuel in the distilling chamber A, and the resulting gas is therefore a mixture
of the above-mentioned gases, the carbonic oxide having the effect of adding
intensity of heat to the combustion, and therefore brilliancy of the hydrocarbon
gas in the flame.
Nothing but ash and clinkers is withdrawn from the bottoin of chamber B
through the open arch W, T, V, Figure 18, and the force of the blast, through P
as well as the rate of frequency in withdrawing the coke from the tank at G, Z¹,
must be always determined by practical trial.
Figure 20 represents the tank or coke discharging side of this apparatus
7, 15, Z, being the bottom line of that tank, and S¹, S, Z, Z, Figure 20, being the
inclined plane to throw out the coke from below the chamber A, as shown at S, Z,
Figure 18.
The open jointed arches 10, 6, Figure 18, are shown in elevation in the sectional
view on line A, A', Figure 19.
Figure 18 shows an inclined plane running back from the wall Z, G, to H, for
the removal of coke by some appliance to be worked by hand, such as a rake,
which would draw the coke out of the water over the edge of the inclined plane
at H.
In Figure 20 the side Z, L³, of the discharging tank may be replaced by a suit-
able inclined plane, up which a chain dredging apparatus of the usual construction
can be made to pass and discharge the coke after traversing with its usual buckets
or plate scrapers the whole length of the tank. By arranging the course of such
an endless chain dredger close to the bottom of the hollow wall, at G, Z, Figure 18,
the coke will fall between the buckets or scrapers, and be thus readily removed
with the aid of steam or other power at any desired rate of unvarying speed. In
Figures 18, 19, and 20 the same letters refer to the same parts.
Figure 21 shows this water-sealed mode of discharging the contents of the hollow
wall applied to the gas making apparatus described in reference to Figures 5 and 6.
The same water-sealed discharger with dredger, as described in reference to
Figures 18 and 20, can also be applied to the hollow wall apparatus generally when
the immersion in water is not injurious to the discharged contents.
Figures 6 and 21 are identical from the top down to Z, N, Figure 6, which is
the bottom of the hollow wall, and below this part the contents of the hollow wall
fall into the water-scaled discharger, as shown in Figure 21, instead of settling in
the open archway, W, T, V, of Figure 6.
The fuel chambers in applications of the hollow wall requiring the use of fuel
should be carefully constructed with the view to affording the readiest possible fall
to the fuel, in order to secure a closely packed screen of red hot fuel through which
no free oxygen can over pass. If a mass of soft coke burns more rapidly than the
surrounding coke on the fire bars of an ordinary apparatus for producing carbonie
oxide a hole in the bed of burning fuel is thus inade through which air rushes
and destroys the gas. In the hollow wall, however, no such contingency can occur,
because the superincumbent wall of fuel crushes down upon and closes every hole
in the burning mass.
To ensure the latter essential condition the walls of the fuel chamber may be
built with a slight inclination, or taper towards each other from the bottom
upwards, or they may be erected perfectly perpendicular, and lined the greater part
of the way down from the top with sheet iron to impart smoothness. The latter
lining may also be applied to the hopper top of the hollow wall in all cases with
advantage.
Owing to the heavy cost of manual labour in stoking retorts under the old
process for making coal gas, and also to the largeness of the outlay for wear and
tear of the retort plant, it has hitherto been the practice to push the distillation of
coal when once in the retort up to that point at which the fixed sulphur com-
pounds of coal are decomposed, thus forming gascous sulphur compounds which
contaminate the gas in spite of costly purification.

page_text: In the aforesaid hollow wall processes for making illuminating gas, however, the
cost of charging and discharging as well as of the slow wear and tear of fire-clay
blocks will be much too small to render complete distillation of the fuel necessary
on that account. For this reason I prefer to always withdraw from the hollow
wall bottom a coke still retaining a considerable percentage of distillable matter,
and therefore of greater market value as fuel. By so doing I obtain the purest
and richest of the hydrocarbon gases with the greatest speed, because such gases are
those which distil most readily, and a quantity amounting to from fifty-six pounds
to one hundredweight of coke will suffice, according to the quality of the fuel under
distillation, for the nearly complete distillation of one ton of coal by direct per-
meation of the deoxidizing flame as already described. The carbonic oxide from the
combustion of so small a percentage of coke per ton of bituminous coal will prove
a large source of gain, notwithstanding the presence of atinospheric nitrogen,
because carbonic oxide when intermixed with rich hydrocarbon gas in even
larger proportion augments the intensity of combustion at the burners, and thus
increases that incandescence of the carbon element upon which the lighting power
of any gas is known to depeud.
An apparatus for perfectly removing sulphur from coal gas, whether made as
aforesaid or in the ordinary or in any other way, can be constructed on the hollow
wall principle by dispensing with the coke chamber B, of Figure 18, and filling the
chamber A with lumps of coke or fire-clay intermixed with ferric oxide. On
passing the impure gas through chamber A, thus charged in the same way as the
blast of air is to be propelled or exhausted in working the apparatus described in
reference to Figure 18, the sulphur will combine with the iron of the ferric oxide
readily, especially if the gas is passed through in a hot state. When the gas is
sent through in a cold state it is best to keep the contents of this hollow wall
scrubber moist by ammoniacal liquor dropping into it from above, this liquor being
made to act as the water scal at the bottom, and being pumped up thence to fall
down in drops through the hollow wall scrubber. The quantity used should not
be enough to wash down the powdered ferric oxide.
Having thus described the nature of my Invention, and the best means known
to me for carrying it into effect, I shall now state my claims, which are as
follows:-
Firstly. The use of a hollow wall apparatus, constructed with open jointed fire-
bricks or other refractory blocks as described, as the means of exposing to the
action of heat any kind of solid matter either in lumps or powder with or without
the oxidation, deoxidation, or fusion of such solid matter.
Secondly. The application of the said hollow wall principle to the manufacture of
gas for illuminating purposes, and also to the purification of gas so made, or of any
other gas by the use of a hollow wall scrubber as herein-before described.
Thirdly. The conversion of the whole of the combustible matter of fuel into
fuel gas by means of the use of the said hollow wall as a distiller of the volatile
matter of such fuel through the heat obtained froin the combustion into carbonic
oxide of the residual fixed carbon of such distilled fuel as described.
Fourthly. The combination as described of the last claimed process for making
fuel gas with the application of the same hollow wall principle to any of the
heating purposes embraced in my first foregoing claim.
Fifthly. The application and use of the said hollow wall principle as the means
of exposing solid or liquid matter to chemical reaction of any kind, by the contact
or permeation of any gas or vapour, more especially for the production of sodic
sulphate, and sulphurous acid as herein-before described.
Sixthly. The application and use of the said hollow wall principle as the means
of exposing any filtering agent in one or more vertical hollow wall screens to the
more rapid passage of any liquid requiring filtration as described, and the use in
such or any other filtering apparatus of a ferruginous carbon, made by the appli-
cation of the said hollow wall principle under my first claim aforesaid as herein-
before specified.

page_text: Seventhly. All the details and arrangements herein-before described so far as
they are necessary to the proper carrying out of the aforesaid applications of my
said newly invented principle of the hollow wall.
In witness whereof, I, the said William Alexander Lyttle, have hereunto set
my hand and seal, this Fourteenth day of November, in the year of our 5
Lord One thousand eight hundred and seventy-six.
W. A. LYTTLE. (L.S.)