Gums and Gum-resins.
Year: 1888

page_text: Date of Application, 6th Jan., 1888
Complete Specification Left, 6th Nov., 1888
Complete Specification Accepted, 5th Jan., 1889
Gums and Gum-resins.
I, WILLIAM HENRY STEAD of Boundary Street, Liverpool in the County of
Lancaster, Seed-crusher, do hereby declare the nature of this invention to be as
follows:-
:-
Some qualities of dextrine and also of other cheap gums have a strong taste and
smell, and consequently cannot be used for postage-stamps, envelopes and other like
purposes for which gum arabic is applied. Similarly there are one or two foreign
guns or gum resins useful for varnish purposes but for the fact that they, too, have
very disagreeable sinells which last for a long time.
Now my invention is designed to produce a tasteless and odorless gum from such
raw material. I dissolve the gum in water or in the case of varnishes in a suitable
solvent and then filter it through animal charcoal or in some cases through other
deodorizing filtrant capable of absorbing taste and smell. The excess of water or of
other solvent is now evaporated until the liquid arrives at the required consistency or
is evaporated to dryness. Jacketed copper pans whether vacuum or open can be used
for this purpose.
The solution in all cases must be sufficiently weak to filter readily and any one of
several well known plans for filtering and deodorizing by means of charcoal can be
used for this purpose.
1000
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
.
Improvements in or relating to the Manufacture or Purification of
Gums and Gum-resins.
I, WILLIAM HENRY STEAD, of Boundary Street, Liverpool, in the County of
Lancaster, Seed-crusher, 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 :-
:-
The cheaper and cruder qualities of dextrine or British gum have a strong and a
unpleasant taste and smell utterly disqualifying them for use for wrappers,- postage
stamps, envelopes, and other like documents which are required to be wetted with the
tongue for closing, also for mucilage or adhesive gum for household,use.
Now by my invention, I have found that I can purify these gums until when used
on postage stamps, or envelopes, and the like, it is almost or quite impossible to
distinguish between them, and the best gum arabic.
The invention is also useful for purifying various other gums and gum resins.
The invention consists in forming a limpid solution of the said gum in any
convenient manner, and filtering the same through animal charcoal, or what is practi-
cally equivalent, shaking the two up together for a considerable length of time, and
then allowing the whole to stand until the charcoal settles and then defecating the
liquid or passing the whole through a filter press. The solvent is then evaporated
from the solution preferably in a jacketed copper pan, either under a partial vacuum
or open.
The solution in all cases must be sufficiently weak or limpid to filter
readily. The animal charcoal if used for filtering gums dissolved in solvents not
soluble in water, should be thoroughly dried immediately before use, preferably by
heating it to about 300 degrees Fahrenheit, and then cooling.
Besides animal charcoal, ordinary dry charcoal, fuller's earth, and other absorbent
defecating material can be used, but none of them are any thing like so efficacious as
animal charcoal. I wish it to be understood that these substances, as far as applicable
for substitutes for animal charcoal, either in whole or in part are included in my
claims under the words animal charcoal.
If the gum be used for mucilage for household use, I add a little nitric acid, just
sufficient to remove the cloudiness. The result is a clear, transparent liquid. If it
is to be sold in a solid state this transparent gum or the original clouded gum is
evaporated to the solid state.
Among the advantages of this process is as far as my experience goes, the following,
namely
That unlike other processes for refining gums, and gum resins, the adhesive-
ness of the raw gum is retained to its full extent in the refined gum, while the
colour is improved.

page_text: Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The manufacture of gum arabic substitute substantially as herein described.
2. The method of purifying gums and gum resins which consists in filtering them
through or in contact with "animal charcoal," substantially as above described.
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1000
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Patent Agents for the Applicant.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
Patent Agents for the Applicant.