IMPROVEMENTS IN AQUEOUS SOLUTIONS OF TANNIN OR TANNING Ooze
Year: 1878

page_text: LETTERS PATENT to George Frederick Redfern, of the General Patent Office,
4, South Street, Finsbury, in the County of Middlesex, Patent Agent, for the
Invention of "IMPROVEMENTS IN AQUEOUS SOLUTIONS OF TANNIN OR TANNING
Ooze." A communication from abroad by James Foley, of Montreal, in the
Province of Quebec, and Dominion of Canada.
PROVISIONAL SPECIFICATION left by the said George Frederick Redfern at
the Office of the Commissioners of Patents on the 28th March 1878.
GEORGE FREDERICK REDFERN, of the General Patent Office, 4, South Street,
Finsbury, in the County of Middlesex, Patent Agent. "IMPROVEMENTS IN AQUEOUS
SOLUTIONS OF TANNIN OR TANNING OOZE." [A communication from abroad by
James Foley, of Montreal, in the Province of Quebec, and Dominion of Canada.]
This Invention has reference to the preservation and protection of tannin or
tannic acid from all the deteriorations to which it is subject in aqueous solutions,
prepared from all kinds of bark, catechu, sumach, divi divi, and all tanning
materials.
The object of the said Invention is to preserve and protect the tannic acid in
tanning ooze from oxidation, decomposition, fermentation, conversion into gallic
acid, and all deterioration, prevent every species of fermentation and organic
decomposition in the ooze, and arrest the development or formation of colouring
matter.
The various kinds of bark and tanning materials yield (apart from the tannic
acid) a variety of soluble extractive matters which exist in the ooze with the tannic
acid, and which are commonly termed sediment; these extractive matters are
capable of inducing fermentation in the ooze, the decomposition of the tannic acid,
and its conversion into gallic acid which is not absorbed by the hides or skins,
thus causing a material loss to the tanner. These extractive matters also produce
a colouring matter or dye in the ooze, which becomes permanently attached to and

page_text: discolours the leather throughout its entire thickness; this colouring matter seems
to be generated through a kind of fermentation in the ooze, which comes on
suddenly both in cold and warm weather, but more frequently in the latter.
Now these improvements consist in the employment or application of sulphur in
the chemically combined form of sulphites, bisulphites, and double sulphites, of the
bases calcium, sodium, potassium, aluminium, and ammonium, separately or in one
or more combinations, by which the tannic acid in aqueous solutions of tannin or
tanning ooze may be preserved from all the herein-before described deteriorations,
and its conversion into gallic acid prevented, fermentation in the ooze may be arrested
and effectually stopped, the formation of colouring matter checked, and its effect
upon the leather modified.
These sulphites may be applied as double sulphites of an alkali and an alkaline
earth by adding them in the form of solid salt or solution to the tanning ooze; the
application and proportion of these chemicals, either separately or combined, will
vary according to the varying strength of the ooze, the nature of the tanning materials
employed, and the nature of the extractive matter extracted with the tannic acid
from the different tanning materials.
ness;
Bisulphite of lime will in practice be found to be the most effective, energetic, and
economical for general use upon an extensive scale; sulphite of soda, either separately
or combined with bisulphite of lime, stands next in point of economy and effective-
these agents may be employed in about the following proportions, videlicet :-
To each separate gallon of tanning ooze of about six degrees strength by the
barkometer I add one-eighth of a pint of bisulphite of lime; if of about twelve
degrees strength, a quarter of a pint, and if about twenty-four degrees strength, a
half pint of the bisulphite of lime separately to each gallon of the tanning ooze. Of
the sulphite of soda, used separately, I take about half an ounce in a dry state, and
if combined with bisulphite of lime a quarter of an ounce dissolved in a quarter of
a pint of bisulphite of lime to each gallon of ooze, thoroughly mixing and blending
these chemicals and the ooze together.
The sulphites of the bases, potassium, aluminium, and ammonium, will accomplish
the desired result (but are not so economical as bisulphite of lime and sulphite of
soda for general use); these sulphites may be introduced in the proportion of
about half an ounce in a dry state or half a pint in a liquid state to each gallon
of ooze.
The exact proportion of the said several sulphites herein described is not material
to the successful performance of the said Invention.
Bisulphite of lime and sulphite of soda, separately or in combination, may be
added to or incorporated with the water to be used in preparing tanning solutions
or ooze in the proportions herein-before described as applied to ooze. By impreg-
nating water with these chemicals previous to its being used over tanning materials,
the solution or ooze produced and the tannic acid therein will not be subjected to
fermentation or deterioration.
Aqueous solutions of tannin or tanning ooze, impregnated with the chemical
sulphites herein-before described, if intended for transportation, may be concentrated
to a semi-liquid state in a vacuum pan, or by other suitable methods employed for
concentrating fluids.
Spent or exhausted ooze discarded by tanners, and which always contains a per-
centage of tannic acid, may be utilized for treating fresh hides, for plumping, fixing
the colour, neutralizing the effect of any unneutralized lime in the hides, and also
for the preparation of fresh ooze by adding five gallons of sulphurous acid to every
hundred gallons of exhausted ooze; this acid will arrest and prevent fermentation,
and keep the spent ooze in a sound condition, even when exposed to high tempe.
ratures.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Frederick Redfern in the Great Seal Patent Office on the
28th September 1878.
GEORGE FREDERICK REDFERN, of the General Patent Office, 4, South Street,
Finsbury, in the County of Middlesex, Patent Agent. "IMPROVEMENTS IN AQUEOUS
SOLUTIONS OF TANNIN OR TANNING OOZE." A communication from abroad by
James Foley, of Montreal, in the Province of Quebec, and Dominion of Canada.
This Invention has reference to the preservation and protection of tannin or
tannic acid from all the deteriorations to which it is subject in aqueous solutions,
prepared from all kinds of bark, catechu, sumach, divi divi, and materials containing
tannin or tannic acid.
The object of the said Invention is to preserve and protect the tannic acid when
in solution and in tauning ooze from oxidation, decomposition, fermentation, con-
version into gallic acid, and all deterioration, to prevent every species of fermentation
and organic decomposition in the solution or ooze, and to arrest the development or
formation of colouring matter.
The various kinds of bark and materials containing tannin or tannic acid yield
(apart from the tannic acid) a variety of soluble extractive matters which exist in
the solution or ooze with the tannic acid, and which are commonly called sediment;
these extractive matters are capable of inducing fermentation in the solution or
ooze, the decomposition of the tannic acid, and its conversion into gallic acid; theso
extractive matters also produce a colouring matter or dye in the solution or oozc;
this colouring matter seems to be generated through a kind of fermentation in the
solution or ooze, which comes on suddenly both in cold and warm weather, but more
frequently in the latter.
Now these improvements consist in the employment or application of sulphur in
the chemically combined form of sulphites, bisulphites, and double sulphites of the
bases calcium, sodium, potassium, aluminium, and ammonium, separately or in one
or more combinations, by which the tannic acid in aqueous solutions of tannin or
tanning ooze may be preserved from the herein-before described deteriorations, and
its conversion into gallic acid prevented, fermentation in the solution or ooze may be
arrested and effectually stopped, and the formation of colouring matter checked.
These sulphites may be applied as double sulphites of an alkali and an alkaline
earth by adding them in the form of solid salt or solution to the tannin solution or
tanning ooze; the application and proportion of these chemicals, either separately
or combined, will vary according to the varying strength of the solution or ooze, the
nature of the material containing the tannin or tannic acid employed, and the
nature of the extractive matter extracted with the tannic acid from the different
tanning materials.
Bisulphite of lime will in practice be found to be the most effective, energetic,
and economical for general use upon an extensive scale, and may be applied to
aqueous tannin solutions or tanning ooze, prepared from all kinds of materials
containing tanurin or tannic acid; sulphite of soda, either separately or combined
with bisulphite of lime, stands next in point of economy and effectiveness; these
agents may be employed in about the following proportions, videlicet :-To each
separate gallon of the aqueous solution of tannin or tanning ooze of about six
degrees of strength, by what is termed the barkoineter, I add one-eighth of a pint
of bisulphite of lime of about the specific gravity one thousand and forty; if of
about twelve degrees of strength, a quarter of a pint; and if of about twenty-four
-

page_text: degrees of strength, a half a pint of the bisulphite of lime separately to each gallon
of the tannin solution or tanning ooze. If the bisulphite of lime employed is of
about the specific gravity of one thousand and seventy only about one-half the
quantity may be used. Of the sulphite of soda, used separately, I take about half
an ounce in a dry state, and if combined with bisulphite of lime a quarter of an
ounce dissolved in a quarter of a pint of bisulphite of lime to each gallon of the
solution or ooze, thoroughly mixing and blending these chemicals and the solution
or ooze together.
The sulphites of the bases, potassium, aluminium, and ammouium will accomplish
the desired result (but are not so economical as bisulphite of lime and sulphite of
soda for general use); these sulphites may be introduced in the proportion of about
half an ounce in a dry state, or half a pint in a liquid state to each gallon of the
tannin solution or ooze.
The exact proportion of the said several sulphites herein described is not material
to the successful performance of the said Invention.
Bisulphite of lime and sulphite of soda, separately or in combination, may be
added to or incorporated with the water to be used in preparing aqueous solutions
of tannin or tanning ooze in the proportions herein-before described as applied to
aqueous solutions of tannin or tanning ooze. By impregnating water with these
chemicals previous to its being used over materials containing tannin or tannic
acid, the solution or ooze produced and the tannic acid therein will not be subjected
to fermentation or deterioration.
Aqueous solutions of tannin or tanning ooze, impregnated with the chemical
sulphites herein-before described, if intended for transportation, may be concentrated
to a semi-liquid state in a vacuum pan, or by other suitable methods employed for
concentrating fluids.
Bisulphite of lime and sulphite of soda, separately or in combination, may be
added to or incorporated with concentrated tannin extracts after being discharged
from the vacuum pan or concentrating vessel in the proportions herein-before
described as applied to aqueous solutions of tannin or ooze to preserve the extract
from fermentation, and the tannic acid therein from deterioration.
Spent or exhausted ooze discarded by tanners, and which always contains a per-
centage of tannic acid, may be utilized for treating fresh hides for plumping, fixing
the colour, neutralizing the effect of any unneutralized lime in the hides, and also
for the preparation of fresh ooze by adding about five gallous of sulphurous acid to
every hundred gallons of exhausted ooze; this acid will arrest and prevent fermen-
tation, and keep the spent ooze in sound condition.
Having now described the Invention communicated to me by my foreign corres-
pondent, and the manner of carrying the same into effect, I wish it to be understood
that what is claimed and intended to be protected by the herein in part recited
Lettors Patent is,-
Firstly. The use and application of bisulphite of lime, separately or in combina-
tion with sulphite of soda, for the preservation and protection of the tannin or tannic
acid in aqueous solutions of tannin and in tanning ooze, and the preservation of
tanning ooze, as herein set forth.
Secondly. The employment or application of sulphur in the chemically combined
form of sulphites, bisulphites, and double sulphites of the bases calcium, sodium,
potassium, aluminium, and amuoniun, separately or in one or more combinations,
either in the form of solid salt or solution, for the purposes set forth.
Thirdly. The use of bisulphite of lime and sulphite of soda, separately or in com-
bination, to incorporate with or impregnate the water to be used in preparing
aqueous solutions of tannin or tanning ooze.
Fourthly. The use and application of bisulphite of lime and sulphite of soda,

page_text: separately or in combination, to preserve concentrated tannin extracts, as set
forth.
Fifthly. The use of sulphurous acid for the purpose set forth.
In witness whereof, I, the said George Frederick Redfern, have hereunto set
my hand and seal, this Twenty-seventh day of September, in the year of our
Lord One thousand eight hundred and seventy-eight.
G. F. REDFERN. (L.S.)