Improvements in the Distillation of Mineral Oils and like Products and Apparatus for that Purpose.
Year: 1889

page_text: Date of Application, 17th Aug., 1889
Complete Specification Left, 16th May, 1890-Accepted, 16th Aug., 1890
Improvements in the Distillation of Mineral Oils and like
Products and Apparatus for that Purpose.
We, JAMES DEWAR, of No. 1, Scroop Terrace, Cambridge, in the County of
Cambridge, Professor of Chemistry, and BOVERTON REDWOOD, of Ballard's Lane,
Finchley, in the County of Middlesex, Analytical Chemist, do hereby declare the
nature of this invention to be as follows:-
Our invention relates to a method of and apparatus for conducting the dis-
tillation of mineral oils in such manner as to obtain heavy oils of high viscosity
needing little subsequent purification suitable for lubricating and other purposes,
the arrangement being such that the distillation can be carried on in a continuous
manner.
For this purpose we conduct the distillation under a regulated pressure lower than
that of the atmosphere in a current of air or other gas that cannot act chemically on
the matter treated in apparatus of the following kind,
We arrange a suitable boiler or retort and a condenser in free communication with
The bottom of the condenser
each other without interposing any valve between them.
communicates with a closed receiving vessel which itself communicates by a pipe
from its bottom with the top of a second closed receiving vessel in which pipe there
is a cock for opening or closing communication between the two vessels. A third
closed receiving vessel is connected by a pipe with the retort at or near the bottom,
The last two mentioned receiving
and is provided with a cock outside the retort.
vessels are provided with outlets at their bottom which can be opened or closed by
means of cocks. All three vessels are connected at top with an air pump by suit-
able pipes provided with cocks so as to open or close them to the action of the
diminished pressure or partial vacuum produced by an air pump. They are also
provided with air inlet pipes opened or closed by means of cocks. The retort itself
is provided with one or more pipes of small bore opening into the outer atmosphere
or communicating with a supply of suitable gas and extending down into and nearly
to the bottom of the retort, the passage of air through which pipes can be regulated
by cocks placed on extensions thereof outside the retort; this has also a pipe for the
admission of the oil to be distilled.
The action of the apparatus is as follows:-
All the cocks on the several pipes being closed the retort is partly charged with oil
to be distilled through the supply pipe which is then closed and the contents are
subjected to heat. The cock from the air pump to the first receiving vessel is then
opened, so producing a vacuum in. this vessel, the condenser and the retort. The
cocks on the small air pipes in the retort are then opened and in consequence of the
partial vacuum in the retort, a current of air or suitable gas is forced to pass through
the oil that is being distilled, but the admission of air or suitable gas is regulated so
as not to interfere with the maintenance of the required diminished pressure.
The oil distilled is condensed in the condenser and passes into the first receiving
vessel on which there is a gauge to indicate the quantity distilled over. As soon as
this vessel is partly filled the second distilling vessel is subjected to the action of the
air pump by opening the cock for that purpose, and communication is then opened
between the two vessels so that the oil collected in the first vessel is discharged into
the second one.
Communication between the two vessels and of the second vessel
with the air pump is then closed, when the second vessel can be discharged without
interfering with the continuous action of the apparatus under the regulated diminished
pressure.
When the residue in the retort becomes too viscid for further treatment, the third
receiving vessel is subjected to the action of the air pump by opening the cock for

page_text: that purpose, so as to produce a partial vacuum therein, and the cock on the pipe
communicating with the bottom of the retort being then opened and the air pressure
in the retort further increased, if necessary, over that of the receiving vessel by the
opening of a special air inlet or the closure of the communication between air pump
and retort, the residue at the bottom of the retort is forced into the said vessel from
which it can be discharged on closing the cocks again and opening others to the
atmosphere. The boiler or retort is then charged with a fresh quantity of oil, and
the above described operation is repeated.
The above method of operating can be modified by so arranging the admission and
discharge of the oil into and from the retort at different levels as to make the
operation continuous.
Dated this 17th day of August 1889.
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in the Distillation of Mineral Oils and like
Products and Apparatus for that Purpose.
We, JAMES DEWAR, of No. 1, Scroop Terrace, Cambridge, in the County of
Cambridge, Professor of Chemistry, and BoVERTON REDWOOD, of Ballard's Lane.
Finchley, in the County of Middlesex, Analytical Chemist, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:
-
Our present invention relates to a method of and apparatus for conducting the
distillation of mineral oils in such manner as to obtain heavy oils of high viscosity
needing little subsequent chemical purification suitable for lubricating and other
purposes, the arrangement being such that the distillation can be carried on in a
continuous manner.
For this purpose we conduct the distillation under a regulated pressure lower than
that of the atmosphere, while air or other gas that does not act prejudicially on the
quality of the resulting oil passes at a low pressure steadily and continuously through
the oil during its distillation.
The apparatus which we employ may be constructed and arranged in various ways.
By way of example one form of such apparatus is shewn in section in the accom-
panying drawing.
We arrange a suitable boiler or retort A and a condenser B in free communication
with each other without interposing any valve between them. The condenser should
have ample surface kept cool by abundant water circulation. It communicates with
a closed receiving vessel C which itself communicates by a pipe
with the top of a second closed receiving vessel D in which pipe e there is a cock
e from its bottom
for opening or closing communication between the two vessels.
receiving vessel E is connected by a pipe
A third closed
with the retort at or near the bottom.
and is provided with a cock outside the retort. The last two mentioned receiving
vessels D and E are provided with outlets H and H at their bottoms which can
be opened or closed by means of cocks. All three vessels are connected at the
top with a pipe P from an air exhausting pump by suitable pipes P1 P2 P³ pro-
vided with cocks so as to open or close them to the action of the diminished pressure
or partial vacuum produced by the air pump.
They are also provided with air inlet pipes p² 7ª opened or closed by means of
cocks. The retort A itself is provided with one or more pipes F of small bore
opening into the outer atmosphere or communicating with a supply of suitable gas
and extending down into and nearly to the bottom of the retort, the passage of air or
gas through which pipes can be regulated by cocks or valves placed on extensions
thereof outside the retort A which has also a pipe 0 for the admission of the oil to be
distilled.
In some convenient part of the boiler or of the pipes connected to it there should
he a gauge indicating the pressure within the boiler. It is also of advantage to f

page_text: in the vapour pipe ascending from the boiler baffle plates Q to catch such liquid as
may be carried up by or condensed from the ascending vapour and return this liquid
to the boiler.
The action of the apparatus is as follows:-
The retort is partly charged with oil to be distilled through the supply pipe 0 and
all the cocks being closed, the contents are subjected to heat. The cock from the air
pump to the first receiving vessel C is then opened so producing a partial vacuum in
this vessel also in the condenser B and in the retort A which are in free communi-
cation with C.
The cocks on the small air pipes F leading into the retort are then opened, and in
consequence of the partial vacuum in the retort a continuous current of air or suit-
able gas is caused to pass at low pressure through the oil that is being distilled, but
the admission of air or suitable gas is regulated by an adjustably loaded valve V or
otherwise, so as not to interfere with the steady maintenance of the required
diminished pressure during the distillation. As the oil becomes vaporised in the
boiler, fresh oil may be supplied, either at intervals or continuously, by the pipe 0.
care being taken that the oil is quite free from admixture of water. The oil
vapour is condensed in the condenser B and the product passes into the firs5
receiving vessel Con which there is a gauge G to indicate the quantity distilled
over. As soon as this vessel is partly filled the second distilling vessel D is sub-
jected to the action of the air pump by opening the cock for that purpose and
communication is then opened between the two vessels C and D so that the oil
collected in C is discharged into D). Communication between the two vessels and
of the second vessel 1 with the air pump is then closed, when the second vessel
can be wholly or partially discharged by opening the air cock and the outlet
cock H without interfering with the continuous action of the apparatus under the
regulated diminished pressure. During the distillation, samples should from time
to time be taken from the vessel D, and these may be classed according to their
density, viscosity or other quality.
When the residue in the retort becomes too viscid for further treatment, or when
the boiler has to be emptied, the third receiving vessel E is subjected to the
exhausting action of the air pump by opening the cock for that purpose so as to
produce a partial vacuum therein and the cock on the pipe e communicating with
the bottom of the retort A being then opened and the air pressure in the retort
further increased if necessary over that of the receiving vessel E either by opening
a special air inlet p or closing the communication by the pipes P P² between the
air pump and the receiving vessels C and D, condenser B and retort A the residue.
at the bottom of the retort is forced into the vessel E from which it can be dis-
charged on closing the rocks in e and P and opening Hand. The boiler or
retort A is then charged by the pipe O with a fresh quantity of oil, and the above
described operation is repeated.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to he performed, we declare that what we
claim is:-
1. The herein described method of distilling mineral oil by subjecting it to heat in
a boiler or retort communicating freely with a condenser and receptacle and with
them subject to a partial vacuum steadily maintained while air or suitable gas at low
pressure is caused to pass the heated oil during the distillation.
2. For distilling mineral oil in the manner above referred to, the combination of a
boiler or retort, a condenser, receptacles for the distilled oil and residues of the dis-
tillation, pipes connected to an exhausting pump, pipe for oil supply and pipes for
admission of air or gas, with suitable cocks and valves, substantially as described.
Dated this 21st day of April 1890
ABEL & IMRAY,
Agents for the Applicants.