IMPROVEMENTS IN THE PURIFICATION OF WATER
Year: 1881

page_text: LETTERS PATENT to Gustav Bischof, of No. 4, Hart Street, Bloomsbury, in
the County of Middlesex, for an Invention of "IMPROVEMENTS IN THE
PURIFICATION OF WATER."
PROVISIONAL SPECIFICATION left by the said Gustav Bischof at the Office
of the Commissioners of Patents on the 23rd June 1881.
GUSTAV BISCHOF, of No. 4, Hart Street, Bloomsbury, in the County of
Middlesex. "IMPROVEMENTS IN THE PURIFICATION OF WATER."
In the Specification of a Patent granted to me on the 29th May 1879, No. 2137,
I described means of purifying water by filtration through spongy iron mixed with
other materials, and I stated that the water passing through this filter dissolves a
portion of the iron, some of which it carries with it. I farther described that when
it is desirable to remove the iron thus carried with the water, a second filtration
may be resorted to.
Since the filing of the said Specification I have discovered that when the water
that is to be filtered is in the first place deprived of carbonic acid, whether free or
in combination, it does not carry with it from the spongy iron filter any
perceptible trace of iron. I therefore, according to my present Invention, com-
bine with a spongy iron filter, such as I described in the said Specification, any
known means of depriving the water of carbonic acid before it enters the filter.
One arrangement which I employ for this purpose is of the following kind:-
Near the settling bed or main reservoir in which the water to be filtered is allowed
to settle, I provide a small reservoir in which I prepare lime water.
I pump this
lime water or allow it to flow by gravity in suitable proportion into the settling
bed along with the main body of water that is entering the bed, so as to mingle
therewith. The water thus treated with lime after settlement is passed from the
settling bed to the spongy iron filter, and it is of advantage so to arrange the
channel for its flow that the water is deflected in its course by several inclined
surfaces, which become encrusted with carbonate of lime deposited from the water.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Gustav Bischof in the Great Seal Patent Office on the
22nd December 1881.
GUSTAV BISCHOF, of No. 4, Hart Street, Bloomsbury, in the County of
Middlesex. "IMPROVEMENTS IN THE PURIFICATION OF WATER."
In the Specification of a Patent granted to me on the 29th May 1879, No. 2137,
I described means of purifying water by filtration through spongy iron mixed with
other materials, and I stated that the water passing through this filter dissolves a
portion of the iron, some of which it carries with it. I farther described that when
it is desirable to remove the iron thus carried with the water, a second filtration
may be resorted to.
Since the filing of the said Specification I have discovered that when the water
that is to be filtered is in the first place deprived of carbonic acid, whether free or
in combination, it does not carry with it from the spongy iron filter any
perceptible trace of iron, I therefore, according to my present Invention, com-
bine with a spongy iron filter such as I described in the said Specification any
known means of depriving the water of carbonic acid before it enters the filter.
One arrangement which I employ for this purpose is of the following kind:-
Near the settling bed or main reservoir in which the water to be filtered is allowed
to settle, I provide a small reservoir in which I prepare lime water.
I pump this
lime water or allow it to flow by gravity in suitable proportion into the settling
bed along with the main body of water that is entering the bed, so as to mingle
therewith. The water thus treated with lime after settlement is passed from the
settling bed to the spongy iron filter, and it is of advantage so to arrange the
channel for its flow that the water is deflected in its course by several inclined
surfaces, which become encrusted with carbonate of lime deposited from the water.
The accompanying Drawing represents diagrammatically a convenient arrange-
ment for the purpose mentioned. Two settling beds A, A', are arranged in
conjunction with one spongy iron filter B. A single lime water tank C will suffice
for the water entering either settling bed which may be used alternately, suitable
sluices or valves being provided by which either can be cut off from the lime water
supply and from the spongy iron filter.
The quantity of lime water should be regulated according to the amount of
carbonic acid contained in the water, either in a free state or in excess above the
quantity contained in mono-carbonates, no more lime being used than what is
necessary to neutralise such amount as may be ascertained by testing or determined
by experience. It is obvious that instead of lime water other alkaline solutions
may be employed.
Having thus described the nature of my Invention and in what manner the
same is to be performed, I claim,-
-
In combination with a spongy iron filter, such as is herein before referred to, the
use of lime water or equivalent agent for neutralising carbonic acid, applied as and
for the purpose herein set forth.
In witness whereof, I, the said Gustav Bischof, have hereunto set my hand
and seal, this Twenty-first day of December, in the year of our Lord One
thousand eight hundred and eighty one.