Process and Apparatus for Extracting Oil from Seeds, Nuts, Beans, and the like.
Year: 1898

page_text: Date of Application, 23rd Nov., 1898
Complete Specification Left, 22nd Aug., 1899--Accepted, 23rd Sept., 1899
PROVISIONAL SPECIFICATION.
Process and Apparatus for Extracting Oil from Seeds, Nuts, Beans,
and the like.
I, GEORGE MITCHELL, of 39, Victoria Street, Westminster, in the County of
Middlesex, Consulting Engineer, do hereby declare the nature of this invention
to be as follows:-
In the case of certain vegetable matter such as nuts, beans, fruit or seeds,
from which oils are extracted it is found impossible to extract the whole of the
oil contained therein in a commercially economical manner by any other methods
save those in which solvents are employed.
This invention relates to the extraction of oil by solvents, and consists in a
process and apparatus in which the substances to be treated are submitted to
the action of the solvent under the most favourable conditions and in a manner
which ensures the separation and extraction of practically the whole of the
oil; the solids being left in a dry condition. Moreover the process can be
conducted in a practically continuous manner, and the resulting mixture of oil
and solvent be drawn off at the point which is the most suitable for its sub-
mission to a treatment subsequent to the actions forming or constituting this
process.
Slight modifications in the order of succession of the actions forming or con-
stituting this process, are permissible without departing from the principle of
my invention as applied to the extraction of oil from ground or otherwise
crushed vegetable matter.
The substance to be treated may have been placed under pressure and a portion
of the oil expressed previous to its being ground into meal or flour which is a
necessary preliminary in preparing the material for treatment by this process.
This powdered substance containing an uncertain quantity of oil is treated in
a suitable vessel by being brought into contact with one of the several known
solvents, preferably carbon bisulphide (C.S2) and the process which forms the
subject of this invention consists in treating the meal or flour in such manner,
that the oil and other soluble matter combined with it, is continuously carried
away by and with the solvent, forming a mixture or combination practically
free from solid matter and in consequence easily susceptible of a further treat-
ment for the separation of the oil from the solvent. The process may be con-
tinuous, and the mixture or combination of solvent and oil leaves the operation
with the least possible quantity of solid matter held in suspension; also the
meal or flour issues from the process practically free from both oil and solvent.
Briefly summarized the complete process allows of the introduction of two sub-
stances (1) the material to be treated (2) the solvent, and has two issues (1) the
oil mixed with the solvent, and (2) the residual dry meal.
When the meal or flour under treatment comes into contact with the liquid
solvent, the finest particles of the former are carried away in suspension in the
latter in its onward movement; but on the solvent being allowed to become
stationary, the solid particles are precipitated; and a special feature of my
invention consists in automatically returning this precipitate back into the
לל

page_text: solvent one or more times for the purpose of repeating the treatment as in the
first instance. The manner of obtaining continuity of the extraction of the oil,
simultaneously with continuous precipitation and return of the precipitate to
the process, is by an arrangement of precipitating chambers disposed in such
manner, that the vertical height of the body of liquid solvent employed in the
treatment chamber is greater than the total height of the precipitating chambers
and their connections which are arranged between the highest and lowest level
of the solvent within the apparatus. The solvent carrying the oil and part of
the fine material in suspension enters the precipitating chamber at the top;
and when this is full the inlet is closed and the outlet from the bottom of the
precipitating chamber is directly connected by a pipe with the lower portion of
the treatment chamber containing the solvent and material under treatment,
there being an intermediary valve which remains closed while the precipitating
chamber is being filled. Two or any greater number of such precipitating vessels
may be worked in series. The precipitating vessels being full and the top closed
the bottom valve is opened, and for illustration the precipitating chamber may
be compared to an inverted bottle full of liquid, its mouth open, and immersed.
Precipitation now commences, the precipitate passing down through the pipe
back into the treatment chamber. The action is really that of displacement,
for as the precipitate leaves the precipitating chamber an equal volume of sol-
vent and oil must necessarily come up the pipe to replace it. Vapour which
might be generated while precipitation is taking place, and thus vitiate the
action, is allowed to escape from the top of the precipitating chamber by a
small pipe connecting it with the treatment chamber at a point in the latter
which is above the maximum height of the solvent. When precipitation is
complete, the connection between the precipitating and treatment chambers is
closed, and the clear combination or mixture drawn off for further treatment.
The meal after leaving the solvent is passed through a tube and subjected to
heat in conjunction with a current of hot air for the purpose of carrying away
the vaporized solvent to the condenser leaving the material a fine meal or flour
practically free from both solvent and oil.
The apparatus used in carrying this process into effect may be varied in details,
but generally speaking it consists of a treatment chamber in which the meal
and solvent are brought into contact: one or more precipitating chambers; and
devices for controlling these; for feeding the meal and solvent to the treatment
chamber; and for removing the meal therefrom. This chamber has the form
of a double tube one limb of which is vertical, and the other vertical through
the greater portion of its height, and inclined at the top towards the vertical
tube both joining and forming part of a box or enclosed hopper; and are con-
nected at the bottom by a horizontal tube, similar to the vertical tubes, the
interior of the whole forms a continuous channel along which is free to pass
an endless chain carrying any convenient and suitable number of trays which
are preferably formed of reticulated material and of such a size as to fit loosely
the interior of the tube. The trays are disposed at equal distances along the
chain and the whole is propelled by any convenient means and guided along the
channel by rotating guides.
Its course is down the vertical tube, along the bottom horizontal tube, up the
partly inclined tube where it passes over one rotating guide, downwardly under-
neath a weighted rotating guide (which keeps the chain at any required tension),
up over a second rotating guide, and thence down the vertical tube.
The meal is automatically fed from a hopper disposed above the highest level
of the solvent, through a branch pipe (preferably by means of a screw), into
the first leg or tube of the treatment chamber and is so regulated that any desired
quantity may be deposited upon each tray passing down the tube.
As soon as
each tray passes the rotating guide at the bottom of the vertical limb of the
treatment chamber, the meal or material contained thereon is left and taken up
by the next following tray thereby ensuring the most perfect admixture of the

page_text: solvent and other material which is then carried up the opposite leg or tube
and freed from the solvent, being ultimately deposited in a hopper between the
two tubes, immediately beneath the hanging rotating guide from which hopper
it is taken by any convenient means (preferably a screw) through heated pipes
or chambers, meeting in these a current of heated air which evaporates and
carries the remaining solvent away to a condenser, while the dry meal issues
from the apparatus.
The liquid solvent is fed into the second leg or tube of the treatment chamber
at its highest working level, which must be a convenient height above the top
of the precipitating chambers. The outlet from the first leg or tube of the
treatment chamber is disposed also above the surface level of the liquid in the
precipitating chambers, but at a lower level than the inlet on the other leg or
tube of the apparatus. The passage of the liquid through the treatment chamber
into the precipitating chamber may be regulated by altering the level of the
solvent on its inlet side.
The combined solvent and oil on leaving the treatment chamber carries with
it a portion of the finer and lighter meal in suspension, and this mixture flows
to one of the precipitating chambers wherein the solid matter precipitates,
leaving the mixed solvent and oil superincumbent. When this separation is
effected a valve placed in a pipe which connects the lower end of the precipi-
tating vessel with the lower horizontal limb of the treatment vessel is opened
and the transference before referred to takes place. When this is complete
the valve is closed and the mixture of oil and solvent drawn off.
A small pipe connects the interior of the precipitating chamber with the upper
end of the treatment chamber for the purpose of allowing any vapour which
may form in the precipitating chambers to escape thus preventing undue pres-
sure interfering with the successful conduct of the process.
Any number of precipitating chambers may be employed in connection with
one treatment chamber, four being preferably used.
Dated this 23rd day of November 1898.
Process and Apparatus for Extracting Oil from Seeds, Nuts, Beans,
and the like.
I, GEORGE MITCHELL, of 39, Victoria Street, Westminster, London, England,
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:-
In the case of certain vegetable matter such as nuts, beans, fruit or seeds,
from which oils are extracted, it is found impossible to extract the whole of
the oil contained therein in a commercially economical manner by any other
methods save those in which solvents are employed.
This invention relates to the extraction of oil by solvents, and consists in a
process and apparatus in which the substances to be treated are submitted to
the action of the solvent under the most favourable conditions, and in a manner
which ensures the separation and extraction of practically the whole of the oil.
Moreover the process can be conducted in a continuous manner, and the result-
ing mixture of oil and solvent be drawn off at the point which is the most suit-
able for its submission to a treatment subsequent to the action forming or con-
stituting this process.

page_text: The substance to be treated may have been placed under pressure and a portion
of the oil expressed previous to its being ground into meal or flour, which grind-
ing is an advantageous preliminary in preparing the material for treatment by
this process.
In all solvent methods a treatment chamber is employed in which the pow-
dered substance containing the oil is brought into contact with the liquid
solvent; carbon bisulphide (CS,) being preferably used. In carrying out the
process which forms the subject of this invention, this treatment chamber has
two or more vertical or inclined limbs into one of which the powdered sub-
stance is fed, carried down therein and up the other by any convenient means.
Below the level of the surface of the liquid in the treatment chamber and above
the level of the lowest end of the same is or are disposed one or more precipi-
tating chambers or displacement vessels, the upper and lower ends of which can
be put into communication with the treatment chamber; these relative levels
of the treatment chamber and the displacement vessels being necessary in order
to enable the essential features of the process to be carried out.
The process allows of the introduction of two substances (1) the material to
be treated (2) the solvent; and has two issues (1) the oil mixed with the solvent
(2) the residual meal. When the substance under treatment is brought into
contact with the liquid solvent, the finer particles of the former remain sus-
pended in the latter while it is in motion, but upon the combined solvent and
oil being allowed to become stationary, the solid particles are precipitated and
the special feature of my invention consists in returning this precipitate back
into the treatment chamber for the purpose of disposal by passing it through
the solvent with the coarser meal. The manner of obtaining continuity of the
extraction of the oil simultaneously with continuous precipitation and return
of the precipitate to the treatment chamber is by the aforesaid arrangement of
the levels of the displacement vessels and the treatment chamber. By this
arrangement the vertical height of the body of liquid employed in the treatment
chamber is greater than the extreme height of the displacement vessels and
their connections, which as before said are disposed between the highest and
lowest levels of the solvent within the treatment chamber.
When the solvent has combined with the oil, this mixture is drawn off from
that point of the treatment chamber which contains most oil, and is allowed
to flow into one of the displacement vessels, bearing with it a small proportion
of fine solid material in suspension. When the displacement vessel is filled,
the communication between it and the upper part of the treatment chamber is
closed, and the outlet from its lower end which communicates with the lower
part of the treatment chamber, opened.
Precipitation now commences the precipitate passing through the outlet to
the lower part of the treatment chamber there mixing again with the meal,
solvent and oil under treatment. The action is really that of displacement,
for as the precipitate leaves the displacement vessel an equal volume of solvent
and oil must necessarily come up the pipe to replace it.
When the precipitation in one particular vessel is complete, the outlet thence
to the treatment chamber is closed and the clear combination or mixture of
oil and solvent drawn off for further treatment.
By employing two or more displacement vessels one may be emptied while
the others are being filled or while the action of precipitation is going on; by
this means the process may be conducted continuously.
The apparatus used for carrying this process into effect may be varied in
detail, the essential features consisting of a treatment chamber of any descrip-
tion which ensures the meal and the solvent being brought into intimate con-
tact a displacement vessel or vessels and devices for connecting these, and for
controlling the meal and solvent supply and delivery. Thus it will be seen that
the apparatus may be extremely simple but for the purpose of explanation I
append drawings shewing a form of apparatus which is found commercially

page_text: devices.
Fig. 2 is an end elevation and
Fig. 3, a plan of same.
Fig. 4 is a vertical section of the treatment chamber shewn with connections
to one displacement vessel only.
Fig. 5 is a vertical section of one of the displacement vessels.
Fig. 6 is a plan of same.
The treatment chamber is composed of two parallel tubes of any convenient
height one of these (that into which the meal is fed) being straight through its
whole length; this is indicated by the letter A. The other tube B is straight
and parallel to the tube A through the greater part of its length, but has a
portion B¹ of its upper end inclined towards the upper end of the tube A with
which it is connected by a box C which forms a continuation of the tubes A
and B¹, and has its lower part so shaped as to constitute a hopper c through
which the treated meal is delivered. The lower ends of the vertical tubes A
and B are connected by a horizontal tube 1) the whole of these tubes A, B, B
and D together with the upper part of the box C forming a continuous channel
or tube of equal diameter internally the points of junction of one tube with
another being rounded at the corners as shewn. The continuous channel formed
by these tubes is occupied by an endless chain E to which at short intervals are
attached trays e the diameter of which is slightly less than the internal diameter
of the tubes forming the treatment chamber so that they can pass freely along
it. The motion of the chain E with the trays e is down the tube A then under
a rotating guide G and along the horizontal tube D; thence under a second
rotating guide G₁ and up the vertical portion of the tube at the top of which
it passes over a third rotating guide G2 and along the inclined tube B¹. At the
top of this it enters the box C passes over a fourth rotating guide G³ and thence
downwardly a short distance and under a fifth rotating guide G; thence upwards
and over a sixth rotating guide G. The guides G, G1, G2, G3 and G4 run in
bearings fixed rigidly to the treatment chamber and the rotating guide G³ is
utilized as a driving guide which propels the chain and trays in their move-
ment along the treatment chamber. But the bearings of the fifth rotating
guide G5 are capable of sliding vertically in slots and are weighted in such
manner that the required tension of the whole chain is maintained. This
weighted rotating guide G³ is disposed in the hopper or box C and is suspended
immediately above an opening in the lower end e of the same through which
opening the treated meal denuded of its oil but containing a small proportion
of solvent falls into a drying apparatus to be hereinafter described.
One
The feeding apparatus by which the meal is supplied to the treatment chamber
consists of a hopper H (disposed above the highest working level of the solvent)
the lower end of which hopper is open to the upper end of an inclined worm
conveyor contained in a casing I; this worm is caused to rotate by means of
wheels, and, spindles and 3; cone pulleys and and a belt 16.
of the cone pulleys (the driver) is fixed on the main driving shaft and by
shifting the belt on to the different speeds of the cone, any required quantity
of meal can be delivered from the lower end of the worm casing I to the interior
of the tube A forming the vertical limb of the treatment chamber and be thus
deposited upon the trays e as they pass in their downward progress; these trays
are preferably formed of reticulated material.
The solvent is fed into the upper end of the tube B at a point near where the
latter joins the inclined portion 13. This feed is necessarily at a higher level
than the meal feed, and at a somewhat higher level than the upper ends of the
displacement vessels to be hereinafter described. Any suitable device for feed-

page_text: ing the solvent into the treatment chamber may be employed but the apparatus L
shewn renders adjustment of the level possible by means of a valve capable of
being moved vertically by a screw ; it also secures that if an excess of the
solvent is forced in, it overflows without in anyway altering the levels of the
solvent and oil in the tubes A and B.
Four displacement vessels marked M, M³, M² and M³ are shewn, and these are
arranged at such heights relative to the treatment chamber and solvent feed as
before stated, the highest liquid level possible in either is below the lowest
possible working level of the solvent in either of the tubes A or B, the lower of
the two outlets from each displacement vessel is at a higher level than the hori-
zontal tube D which forms part of the treatment chamber.
The displacement vessels communicate with the tube A of the treatment
chamber by means of a series of pipes N which are connected in such manner
and so governed by valves n that the liquid can be caused to pass from the treat-
ment chamber to either of the displacement vessels at will; the outlet from
the tube A being arranged at such a height as to tap the liquid contained therein
at the point where the largest proportion of oil is mixed with the smallest pro-
portion of solvent; this mixture holding in suspension a small portion of the
finer and lighter solid matter. The lowest end of each of the displacement
vessels has the form of an inverted truncated cone and is connected by a pipe N¹
with the horizontal pipe D which forms part of the treatment chamber. At
the lower end of each of the displacement vessels is situated a valve m which
is controlled by a vertical spindle m² which passing up and out through the top
of the displacement vessel is capable of being operated by any convenient
device m² for the purpose of closing or opening the valve m. The upper end
of each of the displacement vessels is connected by a pipe m³ with the interior
of the box C which forms part of the treatment chamber; this allows of the
escape of any vapour which forming in the upper ends of the displacement vessels
might produce undue pressure upon the surface of the liquids contained therein
and interfere with the successful conduct of the process.
60
The lower end of the hopper or box C, is connected to the upper end of the
tube and this is continued by the tube O' both being inclined at an angle
of about 45° to the horizon; the lower end of the tube O is connected by means
of a tee piece P¹ to a similar tube P disposed at approximately right angles
to the tube 0. Within the tubes O and P revolve brushes o and p arranged
as to form a screw thumb or worm. The shaft o carrying the brushes in the
tube O is propelled from the main shaft by means of cone pulleys o¹ and o², a
belt o and a shaft of which by means of a pair of bevel wheels drives the shaft pe
This connects with the screw shaft by means of the pair of spur wheels o;
in like manner the worm shaft p is propelled from the shaft 72 by means of
the wheels ³, shaft 74 and wheels 75. The speed of the screw brushes in the
tubes O and P may be altered by any required adjustment of the belt o3 on the
cone pulleys o¹ and 2.
The tubes 0, 0¹, P and P2 are steam jacketed so as to permit of their being
maintained at any required temperature; which may be produced by passing
steam direct into the jacket space; or hot water may be circulated by means of
a steam jet through the jacket spaces in any convenient manner.
The outlet R at the lower end of the tube P2 is connected with an air pump
or other suitable device of any convenient type which maintains a lesser pres-
sure within the apparatus than that of the atmosphere. Hot air is admitted to
the box C at the point C, and passes thence to the tubes 0 and P and in conse-
quence the current of air is downwards in both tubes towards the outlet R and
thence to the air pump.
The meal denuded of its oil is carried from the solvent in the B by the trays,
which as soon as they pass over the guide pulley G2 and enter the tube or drip
box B assume approximately an angle of 45° which allows all free solvent to

page_text: drip free of the next following tray, and flowing along the interior of the tube B¹
to return to its bulk level, in the tube B.
The meal still containing a small portion of the solvent is now carried by
the trays over the guide pulley G3 and under G when it falls clear upon the
upper end of the screw brushes o revolving in the tube 0; thence it passes down
the heated tubes 0 and O' and up the heated tube P. During this time the
remaining solvent is converted into a gas or vapour and is carried with the
descending currents of hot air towards the outlet R from whence it is drawn
by the air pump and again transformed into a liquid for further use. The
meal being freed from the remaining solvent is carried up the tube P by the
worm and passes from the apparatus (through a trap P³) as a dry material
free from oil and solvent. The operation is as follows:-
As
The meal containing more or less oil, is fed into the hopper H in such quanti-
ties as to form a trap, and seal the interior of the tube I and treatment chamber
from the atmosphere; the chain E and trays e are now set in motion and solvent
is forced in through the apparatus L. The chain of trays descending the tube A
receive upon their upper surfaces any desired quantity of meal and carry it
downwards through the solvent bringing the two into intimate contact.
each tray reaches the bottom of the tube A and enters the horizontal tube D it
deposits its load of meal therein and this is taken up and carried along by what
had previously been the underside of the following tray. The trays then pass
up the tube B and by the time they approach the surface they are immersed
in a liquid which is practically pure solvent; the oil having been extracted
from the meal and remaining in the tubes A, D and B. In practice it is found
that the percentage of oil increases gradually from the pure solvent near the
point L down through the tube B along the tube 1 and up the tube A until
at the level indicated by the dotted line 2-2, the largest proportion of oil is
mixed with the solvent; and it is at this point the mixture is drawn off to the
displacement vessels.
When the trays e emerge from the liquid they continue their course up the
drip box B allowing any remaining solvent to drop back into the liquid while
the meal passes over the guide G³ and under the guide G³, being deposited in
the hopper c.
Thence it falls into the upper end of the tube O and passes through
the tubes 0, 0¹ and P to the delivery point P³, the gas being drawn off through
the pipe R as before described.
The liquid mixture at the point N is drawn off to either of the displacement
vessels by opening its valve n; the chamber is allowed to fill and this having
taken place its valve n is closed and m opened. The particles of solid matter
are then precipitated to the bottom of the chamber the precipitate passing
down through the pipe N¹ into the horizontal tube D thus re-entering the treat-
ment chamber and being carried onward with the chain of trays for a second
treatment; being ultimately carried away as part of the dry meal. This delivery
from the displacement vessel is of course one of displacement only; as taking
place below the working level of the liquid in the treatment chamber, the solid
particles precipitating to the tube D are replaced by an equal quantity of lighter
liquid particles. As soon as this displacement is complete the valve m is closed
and the combined solvent and oil drawn off through the pipe S controlled by
the valve s whence it may be conveyed to any suitable receptacle or to an exterior
apparatus for separating the oil from the solvent.
By this system of displacement vessels the lighter particles of meal may be
submitted to the displacement action any number of times, and repeatedly carried
back into the treatment chamber for further treatment. The process is thus
continuous as the chain of trays may run without interruption; one or other
of the displacement vessels being always in action.
In Figure 4 the dotted line 1-1, indicates the mean level of the solvent
inlet; the dotted line 2-2, the level of the outlet to the displacement vessels;,
and dotted line 3-3, the outlet of the mixed solvent and oil.

page_text: Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. A process for extracting oil from seeds, nuts, beans and the like, which
consists in first submitting these in the form of meal to the action of a suitable
solvent; then precipitating any portion of solid matter suspended in the com-
bined solvent and oil, and returning such precipitate to the body of meal and
solvent within the treatment chamber; thereby allowing the combined solvent
and oil to be drawn off from the process free from solid matter, substantially
as described.
2. A process for extracting oil from seeds, nuts, beans and the like in which
the precipitating operation takes place below the surface of the liquid level of
the treatment operation, but above the level of the lowest part of the body of
liquid, in such manner that the precipitating operation, and exchange of material
will take place without interrupting the action within the treatment chamber,
thus rendering the process continuous, substantially as described.
3. A process for extracting oil from seeds, nuts, beans and the like, in which
the precipitating operation takes place below the surface of the liquid level of
the treatment operation, but above the level of the lowest part of the body of
liquid, in such manner that the precipitating operation of displacement inay
take place without interrupting the treatment operation, thus rendering the
process continuous, substantially as described.
4. In apparatus for extracting oil from seeds, nuts, beans and the like, the
combination of a treatment chamber, a solvent feed, a meal feed, one or more
displacement vessels, pipes connecting the upper part of the displacement vessels
and the treatment chamber, pipes connecting the lower part of the displacement
vessels and the treatment chamber, and means for drawing off the solvent and
oil, and the meal separately, substantially as shewn and described.
5. In apparatus for extracting oil from seeds, nuts, beans and the like, the
combination of a treatment chamber, a chain of trays passing round the same,
a solvent feed, a meal feed, one or more displacement vessels, pipes connecting
the upper part of the displacement vessels and the treatment chamber, pipes
connecting the lower part of the displacement vessels and the treatment chamber,
and means for drawing off the solvent and oil, and the meal separately, substan-
tially as shewn and described.
6. In apparatus for extracting oil from seeds, nuts, beans and the like, the
combination of a treatment chamber, a chain of trays passing round the same,
a solvent feed, a meal feed, one or more displacement vessels, pipes connecting
the upper part of the displacement vessels and the treatment chamber, pipes
connecting, the lower part of the displacement vessels and the treatment chamber,
means for drawing off the solvent and oil, and the meal separately and a device
for separating by heat the solvent from the meal, substantially as shewn and
described.