IMPROVEMENTS IN TREATING WOOD AND OTHER VEGETABLE SPIRIT
Year: 1862

page_text: LETTERS PATENT to Hermann Eschwege, of 14, Mincing Lane, in the
City of London, for the Invention of "IMPROVEMENTS IN TREATING WOOD
AND OTHER VEGETABLE SPIRIT."
Sealed the 11th April 1862, and dated the 2nd January 1862.
PROVISIONAL SPECIFICATION left by the said Hermann Eschwege at the
Office of the Commissioners of Patents, with his Petition, on the
2nd January 1862.
I, HERMANN ESCHWEGE, of 14, Mincing Lane, in the City of London, do
hereby declare the nature of the Invention for "IMPROVEMENTS IN TREATING
WOOD AND OTHER VEGETABLE SPIRIT," to be as follows:-
This Invention has for its object improvements in treating wood and other
vegetable spirit. I have ascertained by numerous experiments that charcoal,
particularly wood charcoal, when used at low temperatures in filters has a
most beneficial effect in purifying Spirits (whether obtained in the manner of
wood spirit, or from fermented vegetable substances,) if the affinity which
spirit has for certain impurities be first destroyed by largely diluting it with
water. I, therefore, largely dilute the wood spirit or the alcohol with water,
and then subject the diluted spirit to the action of a succession of wood charcoal
filters at a low temperature, preferring at all times that the filtration should
be carried on below 60° of Fahrenheit. For these purposes it is preferred to
employ a succession of wood charcoal filters, so arranged that the diluted spirit

page_text: shall enter at the bottom of the first filter and rise up and pass away from the
upper part of such filter, and then pass in at the bottom of the next filter, and
so on to the end of the series of filters, and when it is ascertained that the
filtered diluted spirit which is coming away from the last of the series of filters
is not sufficiently pure, the first filter of the series is to be removed and
supplied with fresh charcoal, or another fresh formed filter is to be introduced,
and is made the last filter of the series, and the supply of diluted spirit is then
introduced into the second of the series of the filters, and so on continuously
as the filters require to be changed. The extent to which water may be used
varies in some degree, but most beneficially the spirit is diluted with about 75
to 80 per cent. of water (equal to from 55 to 64 of under-proof spirit); the
water and spirit are well mixed, and then allowed to stand for about twenty-
four hours. After these processes of purification the diluted spirit is to be
brought to the desired strength by distillation.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Hermann Eschwege in the Great Seal Patent Office on the
1st July 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HERMANN
EscuWEGE, of 14, Mincing Lane, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of January, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Hermann Eschwege, Her special licence that I, the said Hermann
Eschwege, my executors, administrators, and assigns, or such others as I, the
said Hermann Eschwege, my executors, 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 vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN TREATING WOOD AND OTHER VEGETABLE SPIRIT," upon the condition
(amongst others) that I, the said Hermann Eschwege, my executors or
administrators, by an instrument in writing under my, or their, or one of
their hands and scals, should particularly describe and ascertain 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

page_text: calendar months next and immediately after the date of the said Letters
Patent.
.
NOW KNOW YE, that I, the said Hermann Eschwege, do hereby declare
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:
This Invention has for its object the improved purification of wood and
other vegetable spirit. I have ascertained by numerous experiments that
charcoal, particularly well burnt wood charcoal, when used at ordinary
temperatures in a series of filters of sufficient size, has a most beneficial
effect in purifying spirits, (whether. obtained in the manner of wood spirit,
or from fermented vegetable substances,) if the affinity which the spirit has
for certain impurities be first destroyed by largely diluting it with water. J,
therefore, largely dilute the wood spirit or fermented spirit with water, and
then subject this diluted spirit to the action of a series of wood charcoal filters
(preferring at all times that the temperature should not exceed 70 degrees of
Fahrenheit's scale), in such a manner that each successive filter shall effect
the filtration of a purer and purer spirit, the same spirit never passing through
a filter to which it has already yielded its impurities, but only through filters
lower down in the series. When it is ascertained that the filtered diluted
spirit which is coming away from the last filter of the series is not any longer
sufficiently pure, the first filter of the series is to be removed, and a fresh filter
to be introduced and made the last filter of the series, and the supply of
diluted spirit is to be introduced into what was the second filter of the series,
and so on continuously as the filters require to be changed. After this process
of purification the filtered spirit is to be brought to the desired strength by
distillation.
Having thus stated the nature of my Invention, I will now proceed to
describe more fully the manner of performing the same.
With regard to dilution, the proportion of water with which the spirit is to
be diluted varies in some degree (according to the nature and purity of the
spirit), but I find that a dilution with from 75 to 80 per cent. of water (equal
to from 55 to 64 per cent. of under-proof spirit) is usually most beneficial; the
water and spirit are to be well mixed and allowed to stand for about 24 hours;
should the diluted spirit have any acid or alkaline reaction I prefer to render
it neutral before setting it aside.
With regard to filtration, the construction, dimensions, and number of the
filters may be varied, but the following is the arrangement I recommend for a
regular daily purification of some 2,000 gallons of proof spirit, that is to
say, of

page_text: some 2,000 gallons of about 56 per cent. :-I prefer to use for this purpose a
series of fifteen filters made of a cylindrical form, about 9 feet in height, and 2
feet in diameter, all hermetically connected together, so as to form a succession,
and provided with the necessary air cocks. In each filter at a few inches
above the bottom, and also at a few inches below the top, is a perforated plate,
and it is between these perforated plates that the charcoal is placed in order to
form the filter. The charcoal should be well burnt and broken into pieces
about the size of peas. I give the preference to charcoal made from light
woods, such as alder, willow, pine, birch, &c. Provision should be made for
connecting each of the filters of a series with the vat or vessel in which the
diluted spirit about to be filtered is contained, and it is preferred that the
arrangements of apparatus used should be such that the diluted spirit should
flow from the vessel containing it into the bottom and below the false bottom
of the filter, which, for the time being, is the first and least clean of the series
of filters. It is also preferred that provision should be made for the diluted
spirit as it passes out from the upper end of the first or other filter in the
series that it shall flow into the bottom of the next filter in the series, and so
on from filter to filter till the diluted spirit passes out of the filter, which for
the time is the last of the series. So soon as it is found that the diluted
spirit coming away from the filter which for the time being is the last filter of
the series is less pure than is desired, the first filter of the series is to be
removed, and a fresh or clean filter is to be introduced into the series after the
filter which was previously the last filter in the series. The supply vessel is to
be connected with the filter which was previously the second filter in the
series, and the process is to go on till the diluted spirit is again found to be
coming away from the newly introduced and now last filter in the series less
pure than is desired, when the filter which has been acting as the first of the
series is to be disconnected, and another fresh or clean filter is to be introduced
into the series, and is to form the last filter of the series, and so on con-
tinuously, whereby the diluted spirit will be at all times successively subjected
to the action of cleaner and cleaner charcoal as it passes from filter to filter
from the time it leaves the supply vat or vessel till it comes away from the
filter which for the time being is the last of the series.
I am aware that it has been proposed before now to filter diluted spirit
through charcoal in order to purify the same, but the degree of dilution and
proportion of filtering surface to be employed in combination are nowhere
shown to the extent which I have found desirable. I would, however, state
that I do not claim generally the filtration of diluted spirit through charcoal
filters, whether one or more filters be employed; but what I do claim is, the

page_text: filtering a sufficiently diluted spirit through a sufficient amount of charcoal in
such a manner that the diluted spirit by passing through a series of charcoal
filters shall be successively and constantly acted upon by cleaner and cleaner
charcoal, which result is accomplished by the introduction or connection from
time to time of a fresh filter to serve as the last filter of the series, and the
removal or disconnection from time to time of the first or foulest filter of
the series.
In witness whereof, I, the said Hermann Eschwege, have hereunto set
my hand and seal, this Third day of June, in the year of our Lord
One thousand eight hundred and sixty-two.
HERMANN ESCHWEGE. (L.s.)