Improvements in Bleaching, Deodorising, and Purifying Fats and Oils, and Apparatus therefor.
Year: 1891

page_text: Date of Application, 23rd Oct., 1891
Complete Specification Left, 23rd Aug., 1892-Accepted, 24th Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in Bleaching, Deodorising, and Purifying Fats and
Oils, and Apparatus therefor.
I WALTER MILLS of 20 Anstey Road Peckham London S.E. Analyst do
hereby declare the nature of this invention to be as follows:—
Certain fats and oils possess either colour smell or taste which renders them less
commercially valuable than if these characteristics were absent. In order therefore
to improve them in these respects I melt them if necessary, raising them to a
temperature of about 120° F., and introduce them into a vessel of special construction
which I call "the mixer."
If the fat or oil is not injuriously affected by hydric sulphate, I then agitate it
with the proper quantity of a solution of sulphuric trioxide dissolved in hydric
sulphate, until the colour or other objectionable feature is destroyed, after which I
allow the acid to subside to the bottom of the fat or oil, which is then drawn off or
decanted.
Sometimes, after the fat or oil is in the mixer, I add the proper quantity of
sulphuric trioxide and intimately mix it with the contents of the mixer; when
this is done the temperature of the mixture is raised if necessary until decomposition
of the sulphuric trioxide takes place.
Or I heat the solution of sulphuric trioxide as aforesaid, or the sulphuric trioxide
per se, in a vessel apart from the oil or fat, conducting the volatilised trioxide into
the oil or fat and intimately mixing it therewith until the desired result has been
obtained. In cases where the action of the volatilised sulphuric trioxide would be
too energetic if used undiluted, I adopt suitable means for diluting it, before
bringing it in contact with the fat or oil. For this purpose of dilution I employ
hot dry atmospheric air.
I prefer to use apparatus constructed so as to enable the foregoing operations to
be conducted under pressure. Afterwards the fat or oil may be washed with water
or alkaline lye, steamed, filtered through animal or wood charcoal, and means
adopted for removing from the fat or oil any traces of hydric sulphate, or of
sulphuric trioxide, or of the product of the action of these substances on the fat
or oil.
Dated this 23rd day of October 1891
COMPLETE SPECIFICATION.
Improvements in Bleaching, Deodorising, and Purifying Fats and
Oils, and Apparatus therefor.
I, WALTER MILLS, of 20, Anstey Road, Peckham, in the County of Surrey,
Analyst, 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 :-
My invention relates to the bleaching deodorising and purification of non-drying
fats and oils and it consists essentially in submitting such fats and oils to the action
of a mixture of gaseous sulphuric trioxide and hot dry atmospheric air in an
apparatus of suitable construction such as that hereinafter described.
To enable my invention to be fully understood I will describe how it can be
carried into practice by reference to the accompanying drawings, in which
Figures 1 and 2 are elevations, partly in section of the left and right hand portions
.

page_text: respectively of an apparatus suitable for bleaching, deodorising and purifying fats
and oils according to my invention.
Figures 3 and 4 are plans of Figures 1 and 2 respectively.
a is the vessel, which I call the mixer" in which the fats or oils to be treated
are placed; is a retort into which sulphuric trioxide or Nordhausen sulphuric acid
is introduced and heated until it assumes a gaseous form or gives off gaseous
sulphuric trioxide; c is a receptacle for the gaseous sulphuric trioxide produced in
the retort b;d is the apparatus in which the atmospheric air is dried and e is a
pump in which the said air is heated by compression; f is a vessel into which the
gas and hot dry air are forced by the pumps 9 and e respectively, and in which
they become united previously to their introduction into the mixer a.
The mixer a is a cylindrical vessel constructed of iron, capable of supporting a
pressure of about 60 lbs. to the square inch. A hollow shaft h, so arranged as to
revolve freely in its bearings, passes through the axis of this cylinder. Com-
municating with the interior of this shaft and revolving therewith are perforated
iron pipes i, i through which the mixture of sulphuric trioxide gas and atmospheric
air is distributed freely into the contents of the mixer. The vessel is fixed in a
tank and has a pipe & therein, opening upwards and communicating with the hollow
shaft has shewn in the drawing. The object of placing the vesself in a tank is to
enable the mixed gas and air to be kept at any desired temperature by filling the
tank with steam, water or other fluid.
The retort bis heated by means of a stove or a steam coil so as to heat the solid
sulphuric trioxide or Nordhausen sulphuric acid placed therein to above a
temperature of 120 degrees Fahrenheit at which temperature gaseous sulphuric
trioxide is produced which passes out through a pipe / into the receptacle or holder c
which is packed or lagged on the outside with suitable non-conducting material m.
From the gas holder c the trioxide gas is drawn by the pump 9 as required,
through the suction pipe n and delivered by the said pump, through the delivery
pipe o and through a pipe p into the vessel f.
The apparatus d for drying the atmospheric air is constructed with a number of
shelves or trays 9 on which is placed a substance such as chloride of calcium, which
will readily absorb moisture. The trays are provided with holes fitted with
nozzles so as to allow free circulation of the atmospheric air through or over the
substance placed upon the trays q. The vessel d is entirely closed except at its
base which is of a conical shape and is inserted in a conical shaped receptacle s
containing ice. Tubest are so fixed between the inner side of the receptacle s and
the base of the vessel d that air can pass freely down them and enter the said
vessel, being cooled in its passage by the ice. The air passes upwards in the
direction indicated by the arrows and having been freed from moisture passes
through the suction pipe u to the compression pump whereby it is heated and
delivered through a pipe v into the same pipe p which receives the sulphuric trioxide
gas and discharges them together into the vesselfin which they become intimately
mixed before passing off through the pipe k, hollow shaft and perforated pipes i
into the fat or oil in the mixer a. The diluted sulphuric trioxide is here decomposed
into its constituents, sulphurous dioxide and oxygen both of which being in a nascent
state bleach, deodorise and purify the fat or oil with which they are brought into
contact.
As a rule I find it desirable to conduct the operation under a slight pressure, two
atmospheres being in most cases sufficient.
After the mixture of air and sulphuric trioxide has acted upon the fat or oil it is
necessary to remove from the latter any carbonaceous or other objectionable
substances which it may contain and this I effect by filtration through animal or
other charcoal, or by washing with water, steaming or other suitable means.
The pumps g and e are actuated by a crank w operated by a pulley a driven from
any suitable motor. Suitable valves and stop cocks are provided to regulate the
flow of the gaseous sulphuric trioxide and of the atmospheric air and to draw off the
contents of the various vessels.

page_text: Some oils, such as petroleum, can be treated in a cold state while other oils and
fats require to be heated or melted. I prefer, however, in all cases to heat the fat
or oil to about 120 degrees Fahrenheit. As it is best to do this while the fat or
oil is in the mixer a, I provide a tank y around the base of the mixer arranged to
be heated by any suitable means.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
(1.) The herein described method of bleaching, deodorising, and purifying non-
drying fats or oils by submitting them to the action of a mixture of gaseous
sulphuric trioxide and hot dry atmospheric air substantially as set forth.
(2.) The apparatus for bleaching, deodorising and purifying non-drying fats or
oils substantially as hereinbefore described and illustrated in the accompanying
drawings.
71.
1
1000
WALTER MILLS.
G. F. Redfern & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.