IMPROVEMENTS IN DISTILLING AND IN APPARATUS THEREFOR.
Year: 1872

page_text: LETTERS PATENT to Robert Porter, of Grove Park, Chiswick, Engi-
neer, and Frederick Porter, of 9, Mincing Lane, in the Oity of
London, Colonial Broker, for the Invention of "IMPROVEMENTS IN
DISTILLING AND IN APPARATUS THEREFOR.
Sealed the 30th August 1872, and dated the 16th May 1872.
PROVISIONAL SPECIFICATION left by the said Robert Porter and
Frederick Porter at the Office of the Commissioners of Patents, with
their Petition, on the 16th May 1872.
We, ROBERT PORTER, of Grove Park, Chiswick, Engineer, and
FREDERICK PORTER, of 9, Mincing Lane, in the City of London,
Colonial Broker, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN DISTILLING AND IN APPARATUS THEREFOR," to be as
follows:-
The object of our Invention is the more rapid and economical dis-
tillation of various substances or materials for obtaining the volatile
liquid and other products of destructive distillation.
This object we accomplish by passing the charge of material to be
distilled in a thin stream through a vertical retort, so that the whole of

page_text: the said charge is kept in contact with the sides of the retort, and the
entire heated surface thereof is utilized, while the central portion of the
retort is left free for the passage of the vapours or gases evolved.
For this purpose we employ a vertical retort of any number of such
retorts either cylindrical or slightly tapered, or preferably of an octagonal
or other polygonal form of transverse section.
The retort is fixed vertically upon a receptacle for the exhausted
charge, and to the upper end of the retort we attach a hopper or
reservoir for containing a supply of the material to be distilled.
Both the hopper and the lower receptacle are in communication with
the retort, and each of them is provided with a suitable lid or cover
secured by luting or otherwise.
In the hopper extending through the same and the retort we place a
central shaft with the upper end projecting through the top of the
hopper. Upon this shaft, at or near the top of the retort, we fix a
worm or screw for feeding the charge from the hopper into the retort.
Below this screw on the said shaft we fit another screw or worm,
extending from end to end of the retort. The threads or blades of this
screw are made to slope or incline downward, preferably at an angle of
about 45 degrees, towards the sides of the retort, to cause the charge in
descending to slide down them to the sides of the retort and lie in the
angles formed by the said blades and the sides of the retorts.
For retorts of large diameter we make the lower or main screw as
follows: Upon the central shaft we fix or string a hollow boss com-
posed of a number of pieces or sections fitting or clutching one upon
another throughout, and from each of the said sections one or more arms
or brackets project outwards at suitable intervals for supporting the
threads or blades of the screw, which are bolted or otherwise attached to
the said brackets.
We prefer to use a double-thread screw, and we make the said. blades
of separate pieces or plates of iron, which we fix to the projecting
brackets on the boss as aforesaid.
.
The exterior diameter of the screw blades is somewhat less than the
internal diameter of the retort, but the width of the blades need not
extend to the boss nor exceed what is requisite for carrying the charge at
the rate at which it is fed by the upper worms, so that any accumulation
of the charge that may occur can fall over the inner edge of the blade

page_text: into the space around the central boss and into the receptacle below.
A clear passage is in the same manner provided for the vapours or gases
arising from the distillation.
For retorts of smaller diameter we make the main screw of a number
of separate lengths or sections, with the blades moulded or cast on to the
central hollow boss in each section. The different sections are fitted so
as to bear or clutch one upon another.
The shaft carrying the screws is caused by suitable gearing to rotate
slowly, and so as to carry the charge gradually from the hopper through
the heated retort, and thence discharge it into the receptacle below,
while the volatile products of distillation pass away through the central
portion of the retort and are conducted away through a suitable aperture
to a condenser of the usual construction, which is maintained at a
suitable temperature.
For heating the retorts to the proper temperature, any suitable
arrangement of furnaces may be employed, but we prefer to set them
either separately or in groups in a brick oven in connection with a
separate furnace.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Porter and Frederick Porter in the Great
Seal Patent Office on the 16th November 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ROBERT
PORTER, of Grove Park, Chiswick, Engineer, and FREDERICK PORTER,
of 9, Mincing Lane, in the City of London, Colonial Broker, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of May, in the year of our
Lord One thousand eight hundred and seventy-two, in the thirty-fifth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto us, the said Robert Porter and Frederick Porter, Her special
licence that we, the said Robert Porter and Frederick Porter, our exe-
cutors, administrators, and assigns, or such others as we, the said Robert
Porter and Frederick Porter, our executors, administrators, and assigns,
should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should

page_text: and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "IMPROVEMENTS IN DISTILLING AND IN APPA-
RATUS THEREFOR," upon the condition (amongst others) that we, the said
Robert Porter and Frederick Porter, our executors or administrators, by
an instrument in writing under our, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Robert Porter, on behalf of myself
and the said Frederick Porter, do hereby declare the nature of our said
Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement,
reference being had to the accompanying Drawing forming a part of this
Specification:-
The object of our Invention is the rapid and economical distillation
of various substances or materials for obtaining therefrom the volatile
liquid and other products of destructive distillation.
Our Invention consists, first, in accomplishing this object by passing
the charge of material to be distilled in a thin stream through a vertical
retort, so that the whole of the said charge is kept in contact with the
sides of the retort, and the entire heated surface thereof is utilized, while
the central portion of the retort is left free for the passage of the vapours
or gases evolved. In the Specification of Letters Patent granted to the
said Robert Porter and to Thomas Lane, bearing date the twenty-second
day of February, A.D. 1872, No. 588, there is described a similar
process for manufacturing illuminating gas from coal, and we wish it
distinctly understood that this part of our Invention does not include
the distillation of coal for the manufacture of gas.
We employ apparatus based upon the same principle of operation as
that described in the said former Specification. But by our present
Invention the apparatus is modified and adapted to other uses than those
described in the said former Specification, the precise manner of its
adaptation to these novel uses being herein-after distinctly shewn. The
vertical retorts described in the said former Specification were circular

page_text: in transverse section, and either cylindrical or slightly tapered, but
although we may use such circular retorts for the purposes of our
present Invention, we adopt the said retorts more effectually to these
purposes by constructing them with an octagonal or other polygonal
transverse section.
The retort is fixed vertically upon a receptacle for the exhausted
charge, and to the upper end of the retort we attach a hopper or
reservoir for containing a supply of the material to be distilled.
Both the hopper and the lower receptacle are in communication with
the retort, and each of them is provided with a suitable lid or cover
secured by luting or otherwise.
In the hopper, and extending through the same and the retort, we
place a central shaft, with its upper end projecting through the top of
the hopper. Upon this shaft, at or near the top or entrance of the
retort, we fix a worm or screw for feeding the charge from the hopper
into the retort. Below this screw on the said shaft we fit another
screw or worm, extending from end to end of the retort. The threads or
blades of this screw, as described in the said former Specification, are
made to slope or incline downward, preferably at an angle of about 45
degrees, towards the sides of the retort, to cause the charge in descending
to slide down them to the sides of the retort and lie in the angles formed
by the said blades and the sides of the retorts.
For retorts of large diameter, or for barrels to be used for evaporating
or heating, we make the lower or main screw as follows:-Upon the
central shaft we fix a hollow boss composed of a number of pieces or
sections fitting or clutching one upon another throughout, and from each
of the said sections, arms, or brackets project outward at suitable inter-
vals for supporting the threads or blades of the screw, which are bolted or
otherwise attached to the said brackets.
We prefer to use a double-thread screw, and to make the said blades
of separate pieces or plates of iron, which we fix to the projecting
brackets on the boss as aforesaid.
The external diameter of the screw blades is somewhat less than the
internal diameter of the retort. The width of the blades need not exceed
what is requisite for carrying the charge at the rate at which it is fed by
the upper worm (or feeder), so that if any accumulation of the charge

page_text: occurs the material can fall over the inner edge of the blade into the
space around the central boss and into the receptacle below. A clear
passage is in the same manner provided for the vapours or gases arising
from the distillation or evaporation.
For retorts of smaller diameter we make the main screw of a number
of separate lengths or sections, with the blades moulded or cast on the
central hollow boss in each section. The main screw constructed and
secured upon its shaft in either of the above ways is described in the
aforesaid former Specification as applied to the manufacture of gas from
coal, but according to our present Invention we apply the said screw
to the distillation of various materials, and we now improve the con-
struction of the said screw by making the blades thereof curved upon
the upper surface. This novel form of the screw is more especially
designed for use in combination with the polygonal, or grooved, or ribbed
retorts.
Another of our improvements consists in using instead of the said
screw a spiral series of steps or ledges fixed on the central shaft or
retort. These improvements are applicable to the manufacture of gas or
for the other purposes of our said Invention.
The shaft carrying the screw is caused by suitable gearing to rotate
slowly, and so as to carry the charge gradually from the hopper through
the heated retort, and thence discharge it into the receptacle below, while
the volatile products of distillation pass away through the central portion
of the retort, and are conducted away through an aperture to a condenser
of any suitable construction.
Our said Invention also consists partly in the following addition to our
improved process :-In some cases, as for instance in distilling oil from
shale, we cause steam or heated air, or gas to pass through the retort to
facilitate the escape of the vapour from the charge, and through the
aperture whereby it is discharged from the retort; but we wish it dis-
tinctly understood that this use of the steam or air is not applicable to
the manufacture of gas from coal.

page_text: Figure 3 is a longitudinal section of a portion of one of the retorts and
main screws, shewn in Figure 1.
Figures 4 and 5 are similar sections, shewing modifications of our
screw.
Figure 6 is a longitudinal section, shewing a contrivance to be used
instead of the said screw.
Figure 7 is a transverse section of a retort with this contrivance.
Like letters indicate the same parts throughout the Drawing.
The Drawing shows our apparatus provided with two retorts a and a*.
The retort a is made cylindrical and the retort a* is polygonal in trans-
verse section. We may however use one, two, or any other number of
either of these retorts. Each retort is provided at the upper end with a
reservoir 6 for containing a supply of the material to be distilled, and it
is fixed upon a chamber c for receiving the exhausted or residual
portions of the charge. This chamber may be a continuation of the
retort. The said reservoir has a cover 6¹, and in some cases is provided
with a sliding valve or door, whereby the admission of the material may
be conveniently regulated and the upward escape of vapour during the
refilling of the retort is prevented. The lower box or receptacle may
also have a cover or adjustable bottom c³, which is kept closed during
the working of the apparatus, but which may be readily opened to dis-
charge its contents. The said receptacle is also in some cases provided
with a valve to permit the escape of vapor. If preferred this receptacle
or the lower end of the retort may be immersed in water, into which the
contents of the retort are discharged, the aforesaid lid or valve being
then unnecessary.
The screw d is placed centrally within the said retort. It is fixed
upon the shaft e, whose upper end extends through the reservoir b. The
said screw is made with one or more threads or blades sloping or inclined
downward towards the outside of the retort, preferably at an angle of
about forty-five or fifty degrees or more; or the upper surface of the
blades used in the polygonal retorts may be curved, as shewn in Figure 5.
This formation of the said screw keeps the material with which the retort
is charged in contact with the heated surfaces thereof as the said material
slides down the inclined blades and lies in the angles a formed at the
outside of the same in descending from the top to the bottom of the
retort. The threads or blades of the said screw may be hollow on the

page_text: under side, as shewn in Figure 3, or solid, as in Figure 4. As above
stated, part of our present Invention consists in making the main screw
with its blades curved. This improvement is clearly illustrated in
Figure 5. And in Figures 6 and 7 we have clearly illustrated the part
of our said Invention, consisting in the use of spirally arranged steps or
ledges with sloping upper surfaces to be used as a substitute for the said
screw. Each ledge corresponds to a small portion of a cone, or is made
curvilinear like the blades of the screw. The charge on each edge being
retarded by contact with the sides of the retort and kept from moving
round with the ledge, falls therefrom to the ledge next below it as the
boss is rotated. By this means the charge is distributed and broken in
its descent, allowing the free evolution of the vapour or gas, while the
risk of any formation of the charge against the retort is obviated.
At or near the top of the retort above the aforesaid screw we fix on
the shaft e a short piece of screw or worm f, which being properly con-
structed and interposed between the reservoir and the retort ensures the
feeding of the material into the latter continuously and at a rate
proportioned to the capacity of the main screw, so that ample space is
left for the free evolution of gas or vapour. The blades of the said
feeding worm may be perpendicular to its axis or inclined thereto.
some cases this separate short screw or worm will not be required.
In
For the distillation of some substances the cylindrical retort a may be
suitable, but for others we prefer to use the polygonal retort a*. The
latter will be found highly advantageous in the manufacture of coal gas,
as the sides and angles of the polygon will hold or retard the pieces of
coal, and prevent their being carried around with the screw instead of
being left by the latter to descend vertically in a thin stream all around
the retort. The prevention of the adhesion of the material to the screw,
and its consequent accumulation upon the same, is of great importance,
as if such accumulation occurs the retort is quickly choked or clogged,
and the process of distillation is impeded or prevented. We obviate to
some extent the evil effects of such accidents by making the under side
of one or more of the upper sections of the screw d solid, as shown in
Figure 4.
Instead of having a polygonal retort we may use a cylin-
drical retort with vertical grooves or ribs for accomplishing the same
purpose.
The upper end of the shaft e has a worm wheel 9 geared with a
worm h on a shaft i, which is driven through a belt or otherwise from a

page_text: steam engine or other motor. By this or other suitable means the shaft e
is caused to revolve slowly, and the charge is admitted to the retort and
permitted to descend gradually through the same. The volatile products
of the distillation pass through the central portion of the retort, and
escape through apertures at either end of the same to a condensor of any
suitable construction, while the waste or exhausted portions of the
charge descend into the receptacle c.
When the latter is full the valve (when a valve is used) is closed to
prevent the escape of any of the volatile products in the retort, and the
door c is opened to discharge the contents of the said box; then the
door is again closed and the valve re-opened. When it is not important
to prevent the escape of the gas or vapour the valve will not be
required.
When it is necessary or desirable to pass steam through the retort for
the purpose herein-before explained, we may conduct the steam to the
lower end of the retort from a boiler through a suitable pipe; but in
those instances where the tank or receptacle c is filled with water the
vapour arising therefrom may be utilized for this purpose.
We may employ any suitable arrangement of furnaces for heating our
retorts, but we prefer to use a brick oven or muffle, as shewn in the
Drawing, the retorts being placed therein either separately or in groups.
In witness whereof, I, the said Robert Porter, have hereunto set
my hand and seal, this Fifteenth day of November, in the year of
our Lord One thousand eight hundred and seventy-two.
Witness,
WM. ROBT. LAKE,
8, Southampton Buildings,
London,
W.C.
ROBERT PORTER.
(L.S.)