IMPROVEMENTS IN TREATING LINSEED OIL
Year: 1861

page_text: LETTERS PATENT to John Fordred, of Brighton, in the County of Sussex,
for the Invention of "IMPROVEMENTS IN TREATING LINSEED OIL."
PROVISIONAL SPECIFICATION left by the said John Fordred at the
Office of the Commissioners of Patents, with his Petition, on the oth
December 1861.
I, JOHN FORDRED, of Brighton, in the County of Sussex, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN TREATING LINSEED OIL,"
to be as follows:-
From various causes the linseed oil of commerce has of late years much
degenerated, and complaints are now constantly made that it will not dry
when made into paint and varnish as it did in former, years.
Now the object of my Invention is to treat such linseed oil, and render it
as valuable an article of commerce and as useful and available in the arts and
manufactures as it was formerly. For this purpose I place the linseed oil in
a suitable vessel and pass, drive, or draw through it heated atmospheric air till
it is known by the change in the oil and alteration of smell that the result.
desired has been attained, care being taken not to allow the temperature to
rise too high. By this process the color of the oil is also in most cases removed
[Price 8d.]

page_text: By continuing to pass air through the oil it may be brought into a state of
great viscidity without the addition of any of the drying ingredients usually
employed in the manufacture of boiled oil. The linseed oil during this
process appears to absorb large quantities of oxygen from the atmospheric
air employed, and thus speedily becomes aged,acquiring the properties of old oil,
whilst its density is at the same time sensibly increased. The same effects
may be produced if the oil be exposed on a large surface, and currents of
heated air be passed or drawn over it, or the oil may be heated in a suitable
vessel and maintained at the requisite temperature whilst it is mechanically
agitated, so as to expose it continuously to the action of the atmosphere.
Another modification of the process is to heat the oil in a suitable vessel,
and force, drive, or draw currents of atmospheric air through it. Superheated
steam may also be driven through the oil to produce a similar effect.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Fordred in the Great Seal Patent Office on the 9th
June 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
FORDRED, of Brighton, in the County of Sussex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Ninth day of December, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Fordred, Her special licence that I, the said John Fordred,
my executors, administrators, and assigns, or such others as I, the said
John Fordred, 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 Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
TREATING LINSEED OIL," upon the condition (amongst others) that I, the said
John Fordred, 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 perforined, 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.

page_text: the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
From various causes the linseed oil of commerce has of late years.much
degenerated, and complaints are now constantly made by those who use it
that it will not dry when made into paint, varnish, &c. as it did in former
years.
Now this Invention consists of a method or methods of treating linseed oil,
whereby it is rendered as valuable an article of commerce and as useful and
available in the arts and manufactures as it was formerly. For this purpose,.
according to one mode, I pass, drive, or draw heated atmospheric air through
the oil till I ascertain by the change iu the oil and alteration of smell that
the desired result has been attained. The best means known to me for
carrying this into effect are as follows:-I take, say, a ton of linseed oil, and
having placed it in a pan or vessel, generally of iron, I cause heated atmo-,
spheric air to pass through the oil, admitting the air through coiled or other
perforated pipes placed in the vessel, or through a perforated false bottom,
with which the vessel is provided, or through what is technically called a rose;
that is, a distributor, consisting of a number of small perforated branch pipes
of various lengths; radiating from the lower end of a central feed pipe passing
into the vessel. I continue to pass air through the oil until I find by the
change in the appearance of the oil, and the alteration in its smell, that the
object desired has been attained; care should be taken not to allow the tem-
perature of the oil to rise too high. I have found the best result is obtained
for most linseed oils by maintaining the oil at a temperature ranging from
230° to 260° Fahrenheit till the process is finished. I find that at 260°
Fahrenheit vapours of acroleine are given off, and at 300° very freely; this;
should be avoided. It is impossible to define the exact time the process will
take,
as it varies with the different kinds of linseed oil,,and likewise depends
upon the quantity operated upon, and also on the purpose for which the oil'is
intended. By this process the color of the oil is materially improved, and in:
some cases entirely removed. The linseed oil during the treatment appears
to absorb large quantities of oxygen from the atmospheric air employed; and
thus speedily becomes oxydized or aged, and thereby acquires the properties of
old oil, whilst its density at the same time is sensibly increased. The oxyda-
tion of the oil by these means being perfectly.under control, the process can be
stopped at any point that the operator may desire, for example, either as soon
as the oil is decolorized, or when it has attained considerable density, for by.

page_text: continuing to pass the air through the oil it may be brought into a state of
great viscidity.
Another mode in which I operate is to heat the oil, and drive, draw, or force
currents of atmospheric air through it. This I prefer to perform thus :-I
heat the oil in an ordinary metallic pan over an open fire, and force, drive, or
draw currents of atmospheric air through it, as previously described. This, all
things considered, is the most economical plan, although in this case the
process requires more care and attention on the part of the operator on
account of the danger from the open fire. Instead of the oil being heated, as
just described, in an ordinary pan over an open fire, it may be heated in a
jacketted metallic pan by steam. In operating on the oil it will be found that
a considerable frothing takes place at first, which after a while subsides; it is
therefore preferable to fill the pan not more than one-half or two-thirds full.
I recommend that the pan should be furnished with a rim or deep curb on its
edge, so arranged as to return the overflow back into the pan, and thereby
avoid waste and danger. I take also what is known in commerce as boiled
linseed oil, by whatever process manufactured, and treat it according to the
methods before described, by which means it can be brought almost into a solid
condition, and is then available for a variety of uses, for which it has not
hitherto been ordinarily employed.
According to another mode I expose linseed oil on an extended surface, and
force currents of heated air over it; for this purpose I fill or pack a tall
vessel, preferably cylindrical, with some non-absorbent substance or substances,
such as pebbles, broken flints, broken glass, or the like, leaving interstices for
the oil to pass down, and I allow the oil to percolate slowly through the mass,
causing it to meet on its way an upward current of heated air, the oil on
reaching the bottom being transferred to the top of the cylinder by means of
a pump or otherwise.
Sometimes, according to another-mode, I heat the oil in a pan or vessel,
preferably of iron, and maintain it at the requisite temperature whilst it is
being mechanically agitated by stirring, so as to expose it continuously to the
action of the atmosphere, the oxydation is in this case, however, slower.
According to another mode, I substitute superheated steam for the currents
of air employed in the various preceding processes, the steam being applied
with the same precautions as were before described in respect of air. The
color of the oil, it is true, may not in some cases be so effectually-discharged-
when steam is used instead of air, nevertheless the employment of steam can
be had recourse to in situations where there are no mechanical arrangements
for forcing or drawing in air. Instead of using superbeated steam, I some-

page_text: times use free steam blown into the oil previously heated, in other respects
proceeding as described with regard to atmospheric air. I sometimes combine
the two systems, that is to say, the use of steam and the use of air.
Having now described the nature of my said Invention, and in what
manner the same may be performed, I wish it to be distinctly understood that
I do not propose by means of my Invention to manufacture what is now
termed in commerce boiled linseed oil; also that I do not apply my Invention
as a portion of or as contributory to the process or operation of converting
raw linseed oil into boiled linseed oil; but what I do claim as constituting my
said Invention is,-
First, the treating of linseed oil by currents of air in manner and for the
purposes herein-before described.
Second, the treating of linseed oil by superheated steam in manner and for
the purposes herein-before described.
Third, the treating of linseed oil by free steam in manuer and for the
purposes herein-before described.
Fourth, the treating of boiled linseed oil by currents of air or by steam in
the manner and for the purposes herein-before described.
In witness whereof, I, the said John Fordred, have hereunto set my
hand and seal, this Seventh day of June, in the year of our Lord One
thousand eight hundred and sixty-two.
Witness,
M. HENRY, Patent Agent,
84, Fleet Street, London.
JOHN FORDRED. (L.S.)