IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL FUEL FROM SLACK, SMALL COAL, OR OTHER SIMILAR COMBUSTIBLE, AND IN APPARATUS THEREFOR
Year: 1881

page_text: LETTERS PATENT to William Phillips Thompson, of the Agencies for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, in the County of Lancaster, and
of 323, High Holborn, in the County of Middlesex, Civil Engineer, for an
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL FUEL
FROM SLACK, SMALL COAL, OR OTHER SIMILAR COMBUSTIBLE, AND IN
APPARATUS THEREFOR." A communication from abroad by M. Neuhaus and
PROVISIONAL SPECIFICATION left by the said William Phillips Thompson
at the Office of the Commissioners of Patents on the 5th September 1881.
WILLIAM PHILLIPS THOMPSON, of the Agencies for Foreign Patent Solicitors,
6, Lord Street, Liverpool, in the County of Lancaster, and of 323, High Holborn,
in the County of Middlesex, Civil Engineer. "IMPROVEMENTS IN THE MANU-
FACTURE OF ARTIFICIAL FUEL FROM SLACK, SMALL COAL, OR OTHER SIMILAR
COMBUSTIBLE, AND IN APPARATUS THEREFOR." A communication from abroad
by M. Neuhaus and O. Henniges, both of Berlin, in the Empire of Germany.
The Invention is best described by the following literal translation of the com-
munication forwarded to me (omitting the claims and other parts unnecessary for a
provisional protection).
The profitable employment of small coal and of small pieces of any kind of
combustible depends on the cheapness with which they can be compressed into a
mass of about the same firmness as that of lumps of coal, without requiring to make
use of any other binding material than that which is contained in the combustible
itself. The combustible brought into a suitable form by a process of compression
of this kind is known under the name of Patent fuel.
Our apparatus serves not only for the performance of the preliminary operations
for the pressing of the combustible into the shape of Patent fuel, but can also be
used by itself without being connected with a press to bring combustibles into a
suitable form for the driving off of their gases.

page_text: required.
1. To dry the combustible.
2. To develop the tar contained in it; and finally
3. To press the combustible.
These three operations are performed in the heated, rarefied space, and for this
purpose we employ the apparatus described below.
The highest part of our drying apparatus is a hopper in which the combustible
is placed after having been previously made as small and as equal-sized as possible
by grinding or pounding. This careful reduction is of course only necessary when
it is intended to press the material afterwards into Patent fuel, and can be dispensed
with when the material is simply to be dried for the purpose of driving off the
gases,
This hopper opens by means of a neck at the bottom into a horizontal cylinder
with double walls, which can be replaced by a double-walled trough, and in which
a worm is placed slightly below the centre, by the turning of which worm the
reduced material is driven from the closed end of the cylinder to the other end
which is open, after which it falls into a reservoir which is also double-walled and
is open at the bottom.
The spaces formed by the double walls of the horizontal cylinder and reservoir,
which are tightly closed all round, are in direct communication with each other by
means of a connecting pipe. For the purpose of heating we carry into both those
spaces the steam blown off from the driving engine, and thus effect the preliminary
drying of the combustible contained in the horizontal cylinder and reservoir
aforesaid. Steam can however be taken from a boiler for this purpose direct.
The long axis of the reservoir is placed nearly or quite vertical in order that
the material to be further acted upon may fall by its own weight merely into the
drying space below. For this purpose the bottom attached to the inner wall of the
reservoir is arranged so as to incline downwards, and terminates in an open neck,
to which the outer wall is tightly attached. This neck can be closed by means of
a slide (or a valve) placed below it.
The part of our apparatus hitherto described serves merely as a preliminary
dryer. The special drying apparatus is arranged directly beneath it, and can be
placed in communication with the preliminary dryer by means of a moveable
funnel. If it is desired to convey the material preliminarily dried in the reservoir
into the special drying apparatus,-this-funnel is pushed in between the latter and
the said neck of the reservoir, and the slide or valve above mentioned is drawn
back. Then the material falls on a second slide placed below which closes the
upper end of a vertical cylinder of the special drying apparatus.
This cylinder
has also double walls. For the purpose of further drying the material which falls
in after the opening of the slide direct boiler-steam is driven through the tightly
closed case formed by the double walls, which steam can be let in through an upper
pipe and out through a lower pipe.
The interior of the vertical cylinder above the steam-casing is placed in commu-
nication with a condenser by means of a side-connecting pipe. This condenser
can be of any approved construction. We have chosen as an example a condenser
with cooling pipes, into which a stream of cold water is introduced through a
pipe at the bottom, which water escapes through another pipe at the top.
The greater part of the vapours constantly developed through the great heating
of the materials in the vertical cylinder are immediately condensed in the con-
denser, and therefore cannot strike back on the material to be dried. Besides this
a partial vacuum is produced by which the mechanical emptying of the vertical
cylinder is at the same time facilitated. This mechanical emptying, which serves
to make the material exposed to the drying become entirely free from air, we effect
as follows:-
From the lower part of the casing of the condenser a pipe leads to an air pump
of other apparatus suitable for extracting. This air is removed from the vertical

page_text: cylinder which is quite full of combustible, and with this air, the steam also which
is developed with great rapidity in consequence, of the vacuum. The combined
action of the condensation and mechanical removal of the steam formed is a very
special characteristic of our process.
In order to ascertain whether the material is sufficiently dry for pressing we
attach to the side connecting pipe of the condenser a sort of hygrometer. At the
side of this connection pipe a pipe leads to a pulley-frame in which an axle is
placed, which bears inside the pulley-frame a lever arm to which a cat-gut is
fastened. The other end of this cat-gut we attach to a screw which stands out on
the outside of the communicating pipe, and which can be suitably set in this com-
municating pipe by means of a thumb-screw. By this means the cat-gut can be
easily stretched to the required extent. To the end of the said axle which projects
out of the pulley-frame a pointer is fastened which is drawn by a spring connected
with the pulley-frame. At the commencement of the drying the cat-gut is drawn
tight by the damp steam acting upon it, that is to say, shortened. As the drying
process proceeds however it lengthens again. The pointer is consequently turned
by the said spring, and it is then easy to observe the progress of the drying by its
position on a scale attached to the pulley frame.
A vacuum meter can be placed on the communicating pipe in order to ascertain
the degree of vacuum produced.
A piece of piping which hangs down into the inside of the vertical cylinder
projects downwards past the above named side connecting pipe of the condenser, and
this prevents the combustibles from getting into the condenser during the time of
the extraction.
The mass which has been sufficiently dried and freed from air is by the opening
of a valve in the lower part of the vertical cylinder taken further down into a
reservoir to which the press can then be attached if the material is to be still
further acted upon so as to make Patent fuel. The capacity of the drying
vertical cylinder is made to correspond with the capacity of the two reservoirs
above and below it. A larger quantity of combustible must be supplied than the
press can work in order that the operation may not be brought to a stand-still.
The reservoir is usually, therefore, not empty when the material is brought into it
from the vertical cylinder. In order to know from the outside when the vertical
cylinder is empty and can be re-filled, we do not fasten the axle of the valve to
the middle of it. Then to this axle a lever is attached outside and a weight is put
on it. This keeps the valve closed when the material put into the vertical cylinder
tends to turn it. By pushing the weight towards the axle the pressure of the mass
opens the valve. After the cylinder has been emptied the action of the weight
closes the valve again. Then before fresh material is put into the cylinder it is
only necessary to push the weight outwards along the lever again, and so on.
The degree of temperature in the cylinder which experience has shewn to be
the best can be easily controlled by attaching a thermometer.
If it is not desired to transform the combustibles into Patent fuel, but only to
prepare them for certain purposes by driving off gases, the press is omitted.
Wherever it is desired to spare expense of retort materials and in general to pro-
duce the greatest effect from them, the preliminary drying of the materials to be
acted upon is to be recommended, as for instance in gas works, paraffin and tar
works, et cetera. Also combustible for domestic use, and especially combustible
for heating the boilers of locomotives and steamers, only produces its greatest
attainable effect when previously dried.
Our drying apparatus described above presents the following advantages over all
other similar apparatus.
It requires no special combustible, because only blow-off steam, or only a small
quantity of direct steam from a boiler is required to heat it. It requires, owing to
the simultaneous action of compensation and mechanical evacuation, to be of small
size only and simple in order to dry a certain quantity of combustible, whilst in
order to dry by air alone and obtain the same result, an incomparably larger and

page_text: more expensive plant is required. It entirely does away with the dust, which is
always an annoyance in the works, and consequently fire is less to be feared; it is
impossible for the mass to burn inside the cylinder or the reservoir, and there
cannot be explosions of gas in these parts because the air is rarefied.
The arrangement and form of the apparatus can be altered without the
fundamental idea of the process itself being changed. The essence of the process
is as follows: --
1. The small combustible is dried in the heated rarefied space.
2. The temperature is kept at the same degree during the drying process not-
withstanding the constant addition of new material and the consequent absorption
of heat.
3. The smallest imaginable space for expansion is allowed to the vapours of
water which are developed before these vapours enter the condenser, because if
this were not so the action of the condenser and of the air pump would be impeded
by the previous powerful expansion of these vapours.
The size of the drying apparatus, and also of the condenser and air pump con-
nected therewith, is of course regulated by the quantity of the production required
in each case.
The formation of tar in the heated mass completely freed from air can be effected
whilst it is in the drying cylinder. The principal development of tar, however,
takes place when the materials are worked for the purpose of making Patent fuel
in the hot press-mould as a result of the pressure required to effect the pressing.
The tar is here the exclusive binding material of the mass, by which its formation
into Patent fuel is rendered possible. A press of any already approved construction
can be employed. The chief condition, however, is that the pressing take place
with the complete exclusion of the outer air in the rarefied space in order that
heavy durable bricks without air spaces may be produced. The mass subjected to
this treatment does not come into contact with the outer air again until it is
thrown out in the form of finished bricks.

page_text: Third. To press the combustible,
These three operations are performed in the heated rarefied space, and for this
purpose is employed the apparatus described below and represented in the accom-
panying Drawing. It is shown in Fig. 1 in vertical section, and in Fig. 2 in side
view; Fig. 3 shows in plan a Patent fuel press which can be dispensed with if the
drying apparatus is only required for the drying of combustibles for the mere
purpose of driving off their gases.
The highest part of this drying apparatus is a hopper A¹ in which the com-
bustible is placed after having been previously made as small and as equal-sized
as possible by grinding or pounding. This careful reduction is of course only
necessary when it is intended to press the material afterwards into Patent fuel, and
can be dispensed with when the material is simply to be dried for the purpose of
driving off the gases.
The hopper A opens by means of a neck at the bottom into a horizontal
cylinder A with double walls, which can be replaced by a double-walled trough
and in which a worm S is placed slightly below the centre, by the turning of
which worm the reduced material is driven from the closed end of the cylinder to
the other end which is open, after which it falls into a reservoir B which is also
double-walled and is open at the bottom.
The spaces formed by the double walls of A and B, which are tightly closed all.
round, are in direct communication with each other by means of a connecting
pipe a. For the purpose of heating we carry into both those spaces the steam
blown off from the driving engine, and thus effect the preliminary drying of the
combustible contained in the cylinder A, and the reservoir B, steam can however
be taken from a boiler for this purpose direct.
The long axis of the reservoir B is placed perfectly (or nearly) vertical in order
that the material to be further acted upon may fall by its own weight merely into
the drying space below. For this purpose the bottom attached to the inner wall of

page_text: the reservoir B is arranged so as to incline downwards, and terminates in an open
neck to which the outer wall is tightly attached. This neck can be closed by
means of a slide b¹ (or a valve) placed below it.
The part of this apparatus hitherto described serves merely as a preliminary
dryer, the special drying apparatus is arranged directly beneath it, and can be
placed in communication with the preliminary dryer by means of a movable
funnel T. If it is desired to convey. the material preliminarily dried in B into the
special drying apparatus, the funnel T is pushed in between the latter and the said
neck of the reservoir B, and the slide b is drawn back. Then the material falls on
a second slide b placed below which closes the upper end of the vertical cylinder D
of the special drying apparatus... This cylinder has also double walls. For the
purpose of further drying the material which falls in after the opening of the
slide b, direct boiler-steam is driven through the tightly closed case formed by
the double walls, which steam can be let in through the upper pipe d and out
through the lower pipe d'
The interior of the cylinder D above the steam-casing is placed in communication
with a condenser C by means of a slide connecting pipe. This condenser can be of
any approved construction. We have chosen as an example a condenser with
cooling pipes into which a stream of cold water is introduced through the pipe cat
the bottom, which water escapes through the pipe c' at the top.
The greater part of the vapours constantly developed through the great heating
of the materials in the cylinder D are immediately condensed in the condenser, and
therefore cannot strike back on the material to be dried, besides this a partial
vacuum is produced by which the mechanical emptying of the cylinder D is at the
same time facilitated. This mechanical emptying, which serves to make the
material exposed to the drying become entirely free from air, is effected as
follows:-
:
From the lower part of the casing of the condenser a pipe leads to an air pump
or other apparatus suitable for withdrawing air from the condenser C and
cylinder D; the air is thus removed from the cylinder D, which is quite full of the
combustible, and with the air the steam also, which is developed with great
rapidity in consequence of the vacuum formed. The combined action of the
condensation and mechanical removal of the steam formed is a very special
characteristic of this process.
In order to ascertain whether the material is sufficiently dry for pressing we
attach to the side connecting pipe of the condenser C (at g) a sort of hygrometer.
At the side of this connecting pipe a pipe g¹ leads to a pulley-frame g, inside of
which an axle is placed which carries a lever arm to which a cat gut g¹¹ is fastened.
The other end of this cat gut g" is attached to a screw which stands out on the
outside of the communicating pipe, and which can be suitably set in this com-
municating pipe by means of a thumb-screw. By this means the cat gut can be
easily stretched to the required extent. To the end of the said axle which projects
out of the pulley-frame a pointer is fastened which is drawn by a spring connected
with the pulley-frame g. At the commencement of the drying the cat gut is
drawn tight by the damp steam acting upon it, that is to say, shortened. As the
drying process proceeds however it lengthens again; the pointer is consequently
turned by the said spring, and it is then easy to observe the progress of the drying
by its position on a scale attached to the pulley-frame. A vacuum-gauge can be
placed on the communicating pipe in order to ascertain the degree of vacuum
produced.
A piece of piping r, which projects down into the inside of the cylinder D,
extends past the above named side connecting pipe of the condenser, and prevents
the combustibles from being drawn into the condenser by the suction from the
mechanical exhauster.
The mass which has been sufficiently dried and freed from air is by the opening
of a valve K in the lower part of the cylinder D taken further down into a
reservoir E, to which the press P can then be attached if the material is to be still

page_text: further acted upon, so as to make Patent fuel. The capacity of the drying cylinder
D is made to correspond with the capacity of the reservoirs B and F above and
below it. A larger quantity of combustible must be supplied than the press can
work in order that the operation may not be brought to a standstill. The reservoir E
is usually therefore not empty when the material is brought into it from D. In
order to know from the outside when the cylinder D is empty and can be refilled
the axle of the valve K is not fastened to the middle of it; then to this axle a
lever K is attached outside, and a weight K" (Figs. 1 and 2), is put on it. This
keeps the valve closed when the inaterial put in the cylinder D tends to turn it. By
pushing the weight towards the axle the pressure of the mass opens the valve;
after the cylinder has been emptied the action of the weight closes the valve again,
then before fresh material is put into the cylinder it is only necessary to push the
weight outwards along the lever again, and so on.
The degree of temperature in the cylinder which experience has shown to be the
best can be easily controlled by attaching a thermometer.
If it is not desired to transform the combustibles into Patent fuel, but only to
prepare them for certain purposes by driving off gases the press P is omitted.
Wherever it is desired to spare expense of retort materials and in general to produce
the greatest effect from then, the preliminary drying of the materials to be acted
upon is to be recommended, as for instance in gas-works, paraffine, and tar works,
etcetera, also combustible for domestic use, and especially combustible for heating
the boilers of locomotives and steamers, only produces its greatest attainable effect
when previously dried.
The drying apparatus described above presents the following advantages over
all other similar apparatus.
It requires no special combustible, because only blow-off steam or only a small
quantity of direct steam from a boiler is required to heat it. It requires, owing to
the simultaneous action of condensation and mechanical evacuation, to be of small
size only and simple, in order to dry a certain quantity of combustible; whilst in
order to dry by air alone and obtain the same result an incomparably larger and
more expensive plant is required. It entirely does away with the dust, which is
always an annoyance in the works, and consequently fire is less to be feared; it is
impossible for the mass to burn inside the cylinder Ď or the reservoir E, and there
cannot be explosions of gas in these parts because the air is rarefied.
The arrangement and form of the apparatus can be altered without the
fundamental idea of the process itself being changed. The essence of the process is
as follows:-
First. The small combustible is dried in the heated rarefied space.
Second. The temperature is kept at the same degree during the drying process,
notwithstanding the constant addition of new material and the consequent
absorption of heat.
Third. The smallest imaginable space for expansion is allowed to the vapours of
water which are developed before these vapours enter the condenser, because if
this were not so the action of the condenser and of the air pump would be impeded
by the previous powerful expansion of these vapours.
The size of the drying apparatus and also of the condenser and air-pump
connected therewith, is of course regulated by the quantity of the production
required in each case.
The formation of tar in the heated mass completely freed from air can be
effected whilst it is in the drying cylinder; the principal development of tar how-
ever takes place when the materials are worked for the purpose of making Patent
fuel in the hot press-mould as a result of the pressure required to effect the
pressing. The tar is here the exclusive binding-material of the mass by which its
formation into Patent fuel is rendered possible. A press of any already
approved construction can be employed, the chief condition however is that
the pressing take place with the complete exclusion of the outer air in the rarefied
space in order that heavy durable bricks without air-spaces may be produced.

page_text: The mass subjected to this treatment does not come into contact with the outer
air again until it is thrown out in the form of finished bricks.
Having thus described the Invention as communicated to me as the best mode
known of carrying it into effect, I wish it to be understood that what I desire to
protect under the herein before in part recited Letters Patent is,―
First. The process for the more effectual and more rapid drying of combustibles
in closed, heated, containing vessels, consisting in condensing the vapour developed
in a condenser separate from the containing vessel, and drawing off the condensed
liquid by means of an air-pump.
Second. In an apparatus for the drying of combustibles for the purpose of
destructive distillation or for the manufacture of Patent fuel. The combination of
the preliminary drier (A', A, B,) and the after-drier (D), situated immediately
beneath and provided with a condenser (C) in connection with an air-pump,
together with the reservoir E or their mechanical equivalents, so that after inserting
the funnel (T) and opening the slides (6', b,) or their equivalents, the material can
fall directly out of the first drier into the after one.
Third. In combination with a drying containing vessel (D) a self-acting closing
valve, such as K, with lever (K¹) and weight (K¹¹) or their equivalents, by means of
which it can be ascertained from the outside when the containing vessel D has
become quite empty.
Fourth. In connection with a drying apparatus for damp combustible the appli-
tion of a hygrometer or damp indicator; in order that the progress of the drying
process may be constantly observed, substantially as described.
In witness whereof, I, the said William Phillips Thompson, have hereunto set
my hand and seal, this Twenty fourth day of February, in the year of our
Lord One thousand eight hundred and eighty two.
W. P. THOMPSON. (L.S.)