Improvements in the Production of Tanning and Dyeing Materials.
Year: 1885

page_text: Improvements in the Production of Tanning and Dyeing
Materials.
I, THOMAS COBLEY of Dunstable in the county of Bedford, Chemist, do hereby
declare the nature of my invention for "IMPROVEMENTS IN THE PRODUCTION OF
TANNING AND DYEING MATERIALS" to be as follows :-
In Forest Districts a large quantity of refuse is made every year to keep the
growth under control, consisting of young shoots, twigs, and leaves; and the object
of the present invention is to utilise this waste for the preparation or Extraction
of Tannic and Gallo-Tannic Acid to be employed in Tanning and Dyeing.
The principal available waste for this purpose is such as contains remunerative
quantities of the hereinbefore mentioned substances, preeminently the Oak from
Oak Forests.
The mode of carrying out the Invention, is to take the waste as collected and
cut it up in a Gorse cutting Machine, or other suitable contrivance, so as to diminish
the bulk and to facilitate the subsequent treatment.
The material thus prepared may then be wholly converted into an Extract by
placing it in Vacuum pans or vessels capable of being heated from the exterior,
either by steam or otherwise (Steam jacketted Boilers) and from which the air can
be excluded.
The minced mass is placed in these vessels, together with a sufficient amount of
water to well cover the mass, to this is added from 1 to 2 per cent of crude carbolic
or creosotic acid, and it is then heated for an hour or two below boiling point.
Where it is not convenient to obtain these agents viz. the crude Carbolic or
Creosotic Acid, the vapours of Wood Tar are introduced into the Boilers, or an
analogous substitute.
The water with which it is intended to be extracted should be de-aerated or
de-oxygenated by first boiling the water and then allowing to cool.
The Liquor thus obtained is run off into a Boiling-down pau, where it is boiled
down to the desired consistency, that is to say, to such strength as to render it fit
for transport at a profit.
Or, the minced mass of waste as above described is dried in any convenient
manner and when sufficiently dry is ground in a Mill similar to that used in
Pains 1

page_text: grinding Sumac, but the grinding is not to be continued to such a length as to grind
up the whole mass into one uniform degree of fineness, but just sufficient to break
the cuticle of the leaf and twig and separate the membranous and fibrous matter
from the dusty portion or meal, which contains the Major portion of the Tannin
in the form of secretion.
The ground mass is then sifted in a sifting Machine Dresser, or Separator, so as
to remove the woody and fibrous matter; the.Powder or meal thus produced may
be sold and used in this state both for Tanning and Dyeing and may be termed
an Oak Leaf Sumac."
The woody fibrous mass left behind is treated as hereinbefore described for the
purpose of removing the remaining portion of Tannic Acid in the form of an
Extract.
AMBROSE MYALL, C.E.,
Agent for the Applicant.

page_text: I, THOMAS COBLEY of Dunstable in the county of Bedford, Chemist 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:
From subsequent investigation I find that the preparation or extraction of tanning
and dyeing materials from Oak Forest waste such as the leaves, twigs and loppings
as described in my provisional specification requires the following complete
description or amplification. If it is desired to produce a material in the form of
an extract, then the waste as described in the provisional specification must be cut
up while green with an ordinary Gorse cutter or other convenient contrivance and
then passed through a pair of corrugated rollers to break open the mass and
facilitate the extraction-Thus prepared the mass is brought into steam jacketted
covered pans or boilers being covered to exclude the air, sufficient water being added
to extract the tannic or gallic principle contained in the same, and to this water
1 or 2
per
cent of crude carbolic or creosotic acid, more or less, is introduced, and
where it is not convenient to obtain these ingredients, then the vapours of wood
tar or wood naptha may be employed in place thereof After heating or digesting
it for several hours below boiling point, say at about 200° Fahrenheit, the liquor is
run off into a boiling pan. The mass being washed out with warm water and this
wash water used for extracting a fresh quantity of material in lieu of fresh water.
This applies to the extraction generally where it is an object to save boiling
down the same liquor and wash waters may be used for a number of operations
until they get so saturated as to need very little evaporation-In both cases whether
the liquor is from a single operation or repeated ones, it must be preferably boiled
down in a covered pan or vessel steam-jacketted, the vapour being drawn off and
condensed. The boiling is continued until the extract has reached the desired
point of concentration.
The condensed water may be used for the purpose of extraction, as it is
preferable the water used should be deaerated or deoxygenated by first boiling and
then allowing it to cool.
In the dry or mechanical preparation of the material it will be necessary to dry
the waste very quickly as a very rapid oxidation goes on even in this process of
drying and I have found that the fibrous or membranous part of the waste is the
most valuable for the purposes of tanning, and the powder for dyeing.
On close examination it will be found that the twigs are furnished with a
quantity of small globular excrescences possessing the nature and properties to a
certain extent of galls and which on being dried and ground will separate out into
powder-The tannic acid contained in this meal or powder after drying and grinding
exists in a form better applicable for dyeing than for tanning, being in this state a
mixture of Gallo-tannic or Gallic Acid. To prepare it the cut and dried waste is

page_text: after drying ground in a mill similar to that in which sumac is ground or a
modification of a bark-mill so adjusted as to reduce the nonfibrous portion to
a powder-The separation of the two substances is effected by a sifting or sieving
machine, provided with brushing apparatus to remove the powder or dust from the
fibrous portion.
The powder may be used for dyeing and the fibrous and membranous portion for
tanning in this condition, or they may be reduced to an extract separately as
in the manner hereinbefore described and in this state applied to their respective
uses.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. The preparation of tanning and dyeing materials from oak or other suitable
forest waste, substantially as herein set forth.
2. The method and means of preparing an extract for tanning and dyeing from
Qak or other suitable forest waste substantially as herein set forth.
3. The method and means of mechanically preparing and separating tanning
and dyeing materials from oak or other suitable forest waste substantially as herein
set forth.