IMPROVEMENTS IN PURIFYING PARAFFIN
Year: 1871

page_text: LETTERS PATENT to John Hodges, of No. 1, York Cottages, York
Road, Wandsworth, in the County of Surrey, for the Invention
of "IMPROVEMENTS IN PURIFYING PARAFFIN."
Sealed the 26th March 1872, and dated the 30th November 1871.:
PROVISIONAL SPECIFICATION left by the said John Hodges at the
Office of the Commissioners of Patents, with his Petition, on the
30th November 1871.
I, JOHN HODGES, of No. 1, York Cottages, York Road, Wandsworth,
in the County of Surrey, do hereby declare, the nature of the said Inven-
tion for "IMPROVEMENTS IN PURIFYING PARAFFIN," to be as follows:-
Heretofore crude paraffin has ordinarily been purified by allowing it
to crystallize slowly after being melted, and by subsequently pressing
the crystallized cake so obtained to express out from amongst the crystals
of paraffin, the fluid and more easily melted portions with which they

page_text: .
are mixed. By this process however a quantity of the fluid and more
easily melted portions still remains enclosed amongst the crystals of
paraffin.
-
To further purify the paraffin the operation is repeated, and in some
cases heavy and light oils have been mixed with the paraffin when
melted, and before allowing it to crystallize in order to facilitate the sub-
sequent expressing out of the fluid and more easily melted portions.
In this case the paraffin after being pressed has required to be subjected
to distillation to distil off, the lighter oils remaining in it.
This process
is expensive and occupies much time.
According to this Invention the crude paraffin having, if desired, been
first separated from.rough impurities is cast into. cakes and allowed as
heretofore to cool slowly so as to form into well-developed crystals.
The cakes are then placed on aj bed of absorbent or porous material (at
present we find dry sand covered with some thin woven fabric, or with
filter paper to answer well), and are then while thus placed exposed to a
warm temperature sufficient to render fluid the more easily melted
portions with which the crystallized paraffin is mixed, but insufficient to
melt the paraffin. The fluid and more easily melted portions then flow
out from between the crystals of paraffin and into or into and through
the absorbent or absorbent and porous materials on which the cake rests.
The cake thus freed from the fluid or fluid and more easily melted
portions may then be treated in any usual method to render it white, or
as much lighter in color as may be practicable, or the process may be
repeated until the separation of the harder from the softer portions has
been effected as completely as is desired, and then any requisite process
for whitening the product may be adopted if needed. The softer portions
may be recovered by any suitable and usual process from the absorbent
1
or porous bed.
1 1441
11.97:
4

page_text: +
WHEREAS, Her most Excellent Majesty Queen Victoria; by Her
Letters Patent; bearing date the Thirtieth day of November, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fifth year, of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said John Hodges, Her special license
that I, the said John Hodges, my executors, administrators, and assigns,
or such others as; I, the said John Hodges; my 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 and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Cliannel Islands,
and Isle of Man, an Invention for, "IMPROVEMENTS IN PURIFYING PARAFFINE,"
upon the conditions (amongst others). that. I, the said, John Hodges,
my executors or administrators, by an instrument in writing under,
my, 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.
99.
NOW KNOW YE, that I, the said John Hodges, do hereby declare the
nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is, to say
"
Heretofore crude paraffine. has ordinarily been purified by allowing it:
to crystallize' slowly after being melted, and by subsequently pressing'
the crystallized cake so obtained to express out from amongst the crystals.
of paraffine, the fluid and more easily melted portions with which they
are mixed. By this process however a quantity of the fluid and more
easily melted portions still remain enclosed amongst the crystals of
paraffine.
3
To further purify the paraffine the operation is repeated, and in
some cases heavy and light oils have been mixed with the paraffine
when melted and before allowing it to crystallize, in order to facilitate
the subsequent expressing out of the fluid and more easily. melted
*
portions. In this case the paraffine after being pressed. has required to
be subjected to distillation to distil off the lighter oils remaining in it.
This process is expensive and occupies much time.
21
4.

page_text: L
'
According to this Invention the crude paraffine having if desired been
first separated from rough impurities, is cast into cakes and allowed as
heretofore to cool'slowly so as to form into well-developed crystals. The
cakes are then placed on a bed of absorbent- or porous material, and are
while thus placed exposed to a warm temperature sufficient to render
fluid the more easily melted portions with which the crystallized
paraffine is mixed, but insufficient to melt the paraffine. The fluid and
more easily melted portions then flow out from between the crystals of
paraffine, and into, or into and through the absorbent or absorbent and
porous materials on which the cake rests: "The cake thus freed from
the fluid or fluid and more easily melted portions may then be treated
in any usual method to render it white or as much lighter in color as
may be practicable; or the process may be repeated until the separation
of the harder from the softer portions has been effected as completely as
is desired; and then any requisite process for whitening the product may
be adopted if needed.
I
.
Having thus described the nature of my Invention, I will proceed to
describe more fully the manner in which I prefer to carry the same into
effect. When working upon paraffine scale as commonly found in the
market I proceed as follows:-I boil the scale with water slightly
acidulated with sulphuric acid and by means of free steam, and then
after a sufficient time has been allowed for settling the imperfect paraffinc
is allowed to crystallize. I allow this crystallization to take place in
trays of tinned iron, into which the fluid imperfect paraffine is ladled or
allowed to flow until each tray is filled to a depth of about two inches.
The trays being enclosed in a room or in closets arranged so that the
cooling can only take place slowly, the cakes of matérial will be found
when solid beautifully crystalline. After the cake has become quite cold
I allow it to remain some hours before proceeding to carry out the next
process, as the separation of the fluid and more easily fusible portions
can be more perfectly effected after the cake has been thus kept for some
time. When the imperfect paraffine lias thus become ready for further
treatment, I-place-each-cake-on-a-porous-bed-which-is-made-by-securely.
fastening one or more layers of a coarse-canvas-known-as-"Hessians"
or bung cloth" on a square, frame of strong open wirework rather
larger than the cake of imperfect paraffine to be operated upon. I
believe that such porous beds are advantageously placed in a sloping
position (as shewn in the Drawings hereunto annexed) so that the
material separated out may readily drop from the wires. I place each
.

page_text: porous bed with the canvas upwards on a tray of tinned iron, so that the
fluid which falls from the bed may be caught by the tray. The porous
bed is supported on small brackets attached to the tray, so that a space
of about half an inch is left between the bed' and the bottom of the tray.
I arrange a set of such porous beds each over its tray in a chamber or
closet as shewn in the Drawings, Figure 1 being a front view, Figure 2
a section from back to front in a vertical plane; Figure 3, a plan of the
top of such a set of porous beds as fitted for.usc.
A, A, is the draining closet which I prefer to form of brick work with
doors of thin iron plates having a layer of boiler felt between them so
as to lessen loss of heat; a, a, a, a, are the porous beds of wirework
covered with coarse canvas; b, b, b, b, are the receiving trays each about
two and a half inches wider than its porous bed; c, c, c, are, rods
fixed into the closet at each end, on which the several trays with their
beds rest; d, d, d, d, are holes in the bottoms of the trays fitted with funnel
pipes through which the fluid separated out passes into any suitable
receptacle. The beds being narrower than the trays do not cover these
holes, and the trays are so placed that the holes stand vertically, one
over another, and thus afford an outlet through the whole series for the
fluid separated out; E, E, is a heating chamber containing a coil or
series of iron pipes e, e, through which steam is allowed to pass; g is a
blast pipe from which a current of air can be made to enter the
chamber E, E. This air heated by the coil e, e, enters the closet A, A,
through openings between the-supports h, h, which carry one end of
each tray. These openings k, k, allow the warmed air to pass between
the trays, afterwards the air rises between the other end of the trays
and the wall of the closet to the exhaust pipe.l. These arrangements
are intended to securé a temperature as nearly as possible equal in all
parts of the closet.
When each bed has been charged with two cakes of imperfect
paraffine formed. as described, and for which cakes I find a size
of about twenty-four inches square and one and three quarters to
two inches thick convenient, the doors of the closet are shut closely,
and steam being admitted to the coil e, e, a blowing fan is set to
work which has its exhaust opening.connected with the pipe 7 and its
blast opening connected with the pipe g. Then a powerful and com-
plète circulation of the air is maintained through the closet A and
chamber E; which has for its object the raising of all parts of the

page_text: 1
T
1.
I
closet. A to an equal temperature, such as the operátor judges to be
suitable: I find that with a paraffine scale of ordinary quality having a
melting point of about 120° Fahrenheit it is convenient to maintain a
temperature of 90° to 100° during the commencement of the process, and
to raise this subsequently to 120° or higher according to the desired
quality of the product and the melting point of the crystals of paraffine.
Soon after the closet has its temperature raised the fluid and the more
easily fusible constituents of the cakes of imperfect paraffine ooze out
into the canvas of the beds, and thence falling into the trays pass by
the funnel
pipes into the receptacle placed for them. The product left
on the beds after draining will be harder and generally whiter as the
temperature of the closet has been higher and as the stay of the material
in the closet has been longer, and vice versa. "When the paraffine left
on the beds has been sufficiently operated on (probably in six hours or
less) it is removed from the beds, and fresh cakes of imperfect paraffine
are arranged for a new operation. The solid residue may be finally
whitened and finished by any of the usual processes, involving, ás
judged best, treatments with acid, alkalies, fuller's earth, animal char-
coal, or other reagents, as is well known. It is to be noted that as: no
light oil, spirit, or naptha has been added to the imperfect paraffine, as is a
usually done when the preliminary purification is to be effected by pres-
sure, no distilling or steaming process is needed for the removal of such
last traces of oil-spirit, or naptha, as by the old method of proceeding
press" could not remove; the more fluid material collected from
the trays may be subjected to any usual and appropriate treatment for
the removal and separation of its more solid-constituents, so that the
fluid portions may be useable for lubrication or other purpose. It is to
be noted also that as sucli more fluid material contains no added oil,
spirit, or inaptha like the pressings out under the. hitherto usually
practised process, so in most cases no fractional distillation is needed
for the separation therefrom of such lighter fluids, but such drained-out
more fluid material after the solid-constituents have been separated from
it, (so far as practicable-or-desireable) by any usual method may be
regarded as rough lubricating oil, and may be prepared by any ordinary
appropriate treatment for use on machinery.
the press
"
It,will be obvious that by a simple arrangement of pipes and valves

page_text: closet (partly losing its heat therein) may be made to traverse the
warming chamber of the next closet, then to go through that next
closet, and so on from one to another until from the last closet it passes.
to the exhaust opening of the fan, and thence to the blast or entrance
pipe of the first chamber as at first. Such a circuit, which is limited in
extent only by the power of the fan to produce the needful amount of
motion in the circulating air, tends much to the economising of the
heat; and it is also obvious. that valves may be so placed in the pipes of
entry and exit for air as that any closet with its chamber may be cut off
from the system of circulation, and then the process may proceed
uninterruptedly in the other closet or closets while such cut-off closets
or chambers are being emptied, recharged, or repaired.
When working upon paraffine obtained from the material, called earth
wax or ozokerit, after distilling the earth wax or ozokerit (the earthy
impurities having been first separated) and mixing all the products
(except the lightest part, which comes over first), and subjecting the
mixture to acid treatment in the manner which is well known, and after
a second distillation and mixing of all the products together, I cast the
mixture into cakes, which are allowed to cool slowly. These cakes of
crude paraffine thus obtained in a crystalline state are then treated in
the manner herein-before described with relation to cakes of crystallized
crude paraffine derived from paraffine scale.
.
Having thus described the mode in which I carry out my Invention,
I wish it to be understood that what I claim is the purification of
paraffine substantially as herein described, the paraffine to be purified
being exposed to a regulated elevated temperature, so that the fluid and
more easily fusible constituents may flow away and be removed from the
paraffine without the aid of artificial pressure.
In witness whereof, I, the said John Hodges, have hereunto set my
hand and seal, this Eighteenth day of May, in the year of our
Lord One thousand eight hundred and seventy-two.
JOHN HODGES. (L.s.)