IMPROVEMENTS IN THE PREPARATION OF A FLEXIBLE COMPOUND APPLICABLE TO WATERPROOFING AND OTHER PURPOSES
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Charles Humfrey at
at the
Office of the Commissioners of Patents, with his Petition, on the
13th June 1868.
I, CHARLES HUMFREY, of Suffolk Grove, Southwark, in the County
of Surrey, Oil Manufacturer, do hereby declare the nature of my
said Invention for "IMPROVEMENTS IN THE PREPARATION OF A FLEXIBLE
COMPOUND APPLICABLE TO WATERPROOFING AND OTHER PURPOSES," to be as
follows:-
over.
On the manufacture of stearic acid from neutral oils and fats by
what is known as the acid process, a large quantity of residuary
pitch remains in the stills after the volatile fatty acids have been distilled
Each different oil or fat when submitted to the acid process
before-mentioned will leave a different residue though all similar in
chemical constitution. Any of these pitchy residues may be employed
for the purposes of this Invention, but I prefer the pitch resulting from
the acidification and distillation of palm oil. To render these products
or pitchy residues flexible and soluble in any ordinary solvents, such as
[Price 8d.]

page_text: turpentine, naptha, petroleum or coal oil, spirits or mixtures of the same,
I mix them with the residuary pitch obtained in the distillation of the
crude oil or tar obtained from boghead and other oil producing coals.
Any of these may be used with success. The residuary pitch obtained
in the distillation of native petroleum may be used, but is not so good
as the coal oil product. By far the best material for rendering palm
oil and other similar residues flexible and soluble is ordinary gas tar,
and as of all other materials I prefer to use this in combination with
palm oil pitch I will describe in detail the process I employ.
The palm
oil pitch can be obtained from any manufacturer of stearic acid, and
does not much vary in quality; the gas tar is also pretty uniform in
quality, and I treat it as follows:-First, the naptha and port of the
dead oil are driven over in an ordinary still, but as it is desirable to
conduct the process with as little heat as possible, the operation is
continued in a shallow open pan provided with a furnace. The heat
is continued with constant stirring until more of the dead oil and all
the creosote and napthaline are evaporated. When cold this tar will
be of the consistency of very thick treacle. Without changing the
boiling pan a quantity of palm oil pitch is then to be added: I find in
practice that about two-thirds of palm oil pitch to one-third of gas tar
will answer.
The evaporation of the mixed materials is then continued
until about four hundredweight from every twenty hundredweight
have passed away. From time to time a small sample as large as a
dropped on to a cold plate of iron, and in a few
minutes, if the boiling is sufficient, this sample though still hot will not
stick to or soil the finger, and when quite cold will be pliant and
flexible.
sixpence should be
For insulating purposes it is important that this compound should be
free from impurities, especially metallic impurities, such as oxide of iron
which is almost always present in gas tar. To effect this purification
I take a copper boiler with vertical sides, about five or six feet deep and
four or five feet diameter, with a flattish bottom, heated by a furnace
and provided with a pipe and draw-off cock placed about a foot from the
bottom. This boiler is filled with the compound and is slightly heated so
as to effect the liquifaction of the compound. The fire is then with-
drawn, the dampers and ash-pit closed, the top closely covered in and
the contents left quiescent for about twenty-four hours. The metallic
and most of the earthy and other insoluble impurities will settle, the

page_text: supernatant compound can be then drawn off and applied for insulating
purposes, and the residue may be used for any other ordinary purpose,
such as varnish making, waterproofing, and the like.