IMPROVEMENTS IN ACTING ON DRYING OILS AND PREPARING VARNISHES
Year: 1853

page_text: LETTERS PATENT to John Webster, at Messrs. Nobles and Hoare's
of 3. Cornwall Road, Stamford Street, in the County of Surrey,
for the Invention of "IMPROVEMENTS IN ACTING ON DRYING OILS AND
PREPARING VARNISHES."
Sealed the 3rd March 1854, and dated the 20th December 1833.
PROVISIONAL SPECIFICATION leit by the said John Webster at
the Office of the Commissioners of Patents, with his Petition, on
the 20th December 1853.
I, JOHN WEBSTER, at Messrs. Nobles and Hoare's, of 3, Cornwall
Road, Stamford Street, in the County of Surrey, do hereby declare tho
nature of the said Invention for "IMPROVEMENTS IN ACTING ON DRYING
OILS AND PREPARING VARNISHES" to be as follows:-
Heretofore in treating linseed and other drying oils, and preparing
varnishes, the oils and materials have been subjected to heat by means
of an open or naked fire, the oils and materials being in a vessel
Price 8d 1

page_text: open to the atmosphere, it having heretofore been considered that
atmospheric air plays an important part in the process.
Now I have discovered that the presence of atmospheric air is
injurious to the process, and that the desired results may be obtained
more advantageously, and the products. less discolored by excluding or
removing atmospheric air from contact with the oils and gums when
subjected to heat to obtain the requisite changes therein. For this
purpose atmospheric air may be excluded by substituting an atmosphere
of steam, vapour, or gas, or the atmosphere may be withdrawn and the
process of heat carried on within a vacuous vessel. The heat requisite:
may be applied in various ways; and although the means of carrying out
the Invention may be varied, it is preferred to carry on the process by
using heated steam to act on the materials in a closed vessel, by which
not only is the atmospheric air excluded, but the requisite heat is also
applied to produce the desired change in. linseed and other drying oils,
and also in gums used in the manufacture of varnishes.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Webster in the Great Seal Patent Office
. on the 19th June 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN WEBSTER, at Messrs. Nobles and Hoares, of 3, Cornwall Road,
Stamford Street, in the County of Surrey, send greeting.
WHEREAS Hernost Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of December, in the
year of our Lord One thousand eight hundred and fifty-three, in the
seventeenth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Webster, Her special
licence that I, the said John Webster, my executors, administrators,
and assigns, or such others as I, the said John Webster, my execu
tors, 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

page_text: vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
ACTING ON DAYING OILS AND PREPARING VARNISHES," upon the condition
(amongst others) that I, the said John Webster, by an instrument in
writing under my hand and seal, should particularly describe and ascer-
tain 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.
NOW KNOW YE, that I; the said John' Webster, do hereby
déclare 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):-
Héretofore in treating' linseed and other drying oils and preparing
varnishes, the oils and materials have been subjected to heat by means
of an open or naked fire, the oils and materials being in a vessel
open to the atmosphere, it having heretofore been considered that
atmospheric 'air plays an important part in the process.
Now I have discovered that the presence of atmospheric air is
injurious to the process, and that the desired results may be obtained
more advantageously and the products less discolored by excluding or
removing the atmospheric air from contact with the oils and gums when
subjected to heat to obtain the requisite changes therein. For this
purpose atmospheric air may be excluded by substituting an atmosphere
of steam, vapour, or gas, or the atmosphere may be withdrawn, and the
process of heat carried on within a vacuous vessel. The heat requisite
may. be applied in various ways; and although the means of carrying
out the Invention may be varied, it is preferred to carry on the process
by using heated steam to act on the materials in a closed 'vessel, by
which not only is the atmospheric air excluded, but the requisite heat is
also applied to produce the desired change in linseed and other drying
oils, and also in gums used in the manufacture of varnishes.
Having thus stated the nature of my said Invention, I will proceed
to explain the manner of performing the same.
The object as above. explained is to exclude the atmosphere from

page_text: contact with the matters under process when they are in a-highly
heated state, and I may here observe the form of the vessel and the
mode of keeping out the atmosphere may be varied without departing
from my Invention.
1.
I will, however, describe the manner the Inven-
tion is now practised. In place of using the ordinary open vessel or
boiler, I use a vessel either in the form of a still, or otherwise closed
in at the upper part, and to facilitate the introduction of the charge,
and to admit of getting at the interior of the vessel, I have a man-hole
or covered opening in the vessel. The vessel is provided with a cock
or tap or other convenient instrument to draw off the charge, .and
also to draw out samples to ascertain the progress of the process; and
the vessel is also provided at the upper part with a pipe, with a throttle
or other valve to regulate the passage outwards of the steam and
vapours from the vessel, and there is a tube (to receive a thermometer)
closed at the lower end which descends a short distance below the
surface of materials in the vessel. The vessel has within. it a .coil of
pipe (below the surface of the charge) perforated with small holes,
through which steam.is allowed to flow into the vessel; and the vesse!
is heated externally by a fire. I would here state that I make no
claim to such a construction of vessel, nor do I claim the introduction
of steam.into such a form and arrangement of vessel, like arrangements
having been before employed, for other purposes. And I would state that
I prefer to employ steam as the means of removing and keeping out
of the atmospheric air, but it will be evident that other well known
means of doing so may be resorted to. And in.: using steam I have
only found it necessary to use steam a few pounds pressure in the
boiler over the pressure of.the atmosphere.. The steam may be used
without being heated, and the chief heat:obtained from an external
fire, or the steam may be highly heated. after passing from the boiler
and before passing into the vessel, by which much or all the heat
necessary may be derived from the steam. In working according to
my Invention a quantity of gum resin, resins, or matters usually
employed in the manufacture of varnishes are introduced into a vessel
such as above described, and the same are melted by the heat of the
external fire; the proper quantity of drying oil is then introduced and

page_text: stirred in. The heat is then to be raised, steam being admitted into
the vessel so as to drive and keep out the atmospheric air. For this
purpose the throttle or other valve is only kept open to such an extent
as to ensure a moderate degree of pressure on the interior which will
ensure the keeping out of the air. The heating of the materials I
believe to be best from about 500° to 700° of Fahrenheit, but lower
or higher degrees of heat may be employed, lower temperatures taking
more and higher temperatures taking less time. The process of heat
and of excluding the air is to be carried on till the workman finds by
a sample drawn out of the vessel that the matters under process have
arrived at that state which is technically called "sufficiently boiled,"
when the fire is to be drawn. The air, however, is to be excluded by
steam or otherwise, till the matters are considerably cooled, say to
about 250° Fahrenheit. The matters are then treated and finished in
the same manner as if the boiling had been, as heretofore, in the open
air. When drying oils alone are to be treated according to my
Invention, they are to be boiled in a vessel such as above described
with the air excluded until they are brought to the consistency
desired, and cooled down, as described; they are then to be treated as
heretofore.
Having thus described the nature of my Invention, and the best
manner I am acquainted with for performing the same, I would have
it understood that what I claim is, the acting on drying oils and
oreparing varnishes, as above explained.
In witness whereof, I, the said John Webster, Rave hereunto
set my hand and seal, this Nineteenth day of June, in the year
of our Lord One thousand eight hundred and fifty-four.
JOHN WEBSTER. (L.S.)
Witness,
S. CARPMAEL."