Improvements in the Manufacture of Porous, Hard, and Acid- resisting Plates, Bricks, and Pipes for Filtering and like Purposes.
Year: 1895

page_text: Date of Application, 4th Oct., 1895
Complete Specification Left, 1st July, 1896-Accepted, 15th Aug., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Porous, Hard, and Acid-
resisting Plates, Bricks, and Pipes for Filtering and like
Purposes.
I, WILHELM SCHULER of Isny, Wurtemberg in the Empire of Germany,
Manufacturer, do hereby declare the nature of this invention to be as follows:-
A great number of processes have hitherto been employed for making porous
plates, bricks or pipes for filtering and like purposes, but all attempts have
without exception yielded defective results. It has not hitherto been possible
to produce filter bricks combining the properties of great porosity, considerable
hardness, capability of resisting acids, and especially also even form and smooth
surface.
Among well known attempts to make filter plates, those having for their object
plates formed by vitrifaction appear to be the most worthy of consideration. But
even these plates have great drawbacks which render their sale impossible. The
manufacture is firstly extremely inconvenient and costly, and the plates owing to
their rough surface are soon choked by the accumulation of impurities, and become
ineffective and therefore unuseable.
My invention has for its object to remove all the above drawbacks, and it
consists in the following extremely simple process:-
Equal parts by volume of calcined kieselguhr (diatomaceous earth) washed
powdered quartz, and soda water glass, are mixed in as dry a state as possible,
placed in suitable moulds and strongly pressed. The substance hardens in the air
in a short time (usually a few hours) and is then burnt at a temperature very
slowly rising up to a clear red heat. After being allowed to cool slowly, a brick
is obtained of small specific gravity which is eminently qualified for filtering
purposes, such for instance as great porosity, and hardness, even form with smooth
surfaces, great strength and durability and capability of resisting acids. A special
property of this substance when dried is that it does not shrink in the burning and
hence its dimensions are not altered.
The use of kieselguhr (diatomaceous earth) for filtration purposes is well
known. The addition of ground quartz has for its object to so far remove the
great elasticity of the kieselguhr that the mass may be compressed. The forma-
tion of bricks by the cold process is however only rendered possible by the
addition of waterglass, and further during the burning a silicate compound which
According as more
is extremely favourable for filtration purposes is formed.
or less ground quartz is added, a correspondingly higher pressure can be employed
and thereby a brick of less or more porosity be obtained. By the addition of
organic substances such as saw-dust the porosity may if desired be considerably
increased.
The technical advantages of filter bricks produced by this process are:
uniform porosity and smooth exterior surface whereby the finest subdivided
solid substances are retained on the surface and the great danger of choking is
prevented.
The cleaning of such filter plates may also be easily effected by return currents
(back washing) or by re-burning the plates. Pipes made by this process are
especially suitable for filtering purposes on a small scale.

page_text: Ground material in the form of sand made from the bricks hereinbefore
described is also valuable as a preliminary filter for retaining the coarser
impurities in water which is to be purified mechanically.
Dated this 3rd day of October 1895.
WM. P. THOMPSON & Co.,
Of 6 Lord Street, Liverpool, Agents for the Applicant.
Improvements in the Manufacture of Porous, Hard, and Acid-
Plates, Bricks, and Pipes for Filtering and like
resisting
Purposes.
I, WILHELM SCHULER, of Isny, Wurtemberg, in the Empire of Germany,
Manufacturer, 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 :-
A great number of processes have hitherto been employed for making porous
plates, bricks or pipes for filtering and like purposes, but all attempts have
without exception yielded defective results. It has not hitherto been possible
to produce filter bricks combining the properties of great porosity, considerable
hardness, capability of resisting acids, and especially also even form and smooth
surface.
But
Among well known attempts to make filter plates, those having for their object
plates formed by vitrifaction appear to be the most worthy of consideration.
even these plates have great drawbacks which render their sale impossible. The
manufacture is firstly extremely inconvenient and costly, and the plates, owing to
their rough surface, are soon choked by the accumulation of impurities, and become
ineffective and therefore unusable.
My invention has for its object to remove all the above drawbacks, and it consists
in the following extremely simple process:
-
Equal parts by volume of calcined kieselguhr (diatomaceous earth) washed
powdered quartz and soda waterglass, are mixed in as dry a state as possible,
placed in suitable moulds and strongly pressed. The substance hardens in the air
in a short time (usually a few hours) and is then burnt at a temperature very
slowly rising up to a clear red heat. After being allowed to cool slowly, a brick
is obtained of small specific gravity which is eminently qualified for filtering
purposes, such for instance as great porosity and hardness, even form with smooth
surfaces, great strength and durability and capability of resisting acids. A special
property of this substance when dried is that it does not shrink in the burning and
hence its dimensions are not altered.
The use of kieselguhr (diatomaceous earth) for filtration purposes is well
known. The addition of ground quartz has for its object to so far remove
the great elasticity of the kieselgubr that the mass may be compressed. The
formation of bricks by the cold process is however only rendered possible by the
addition of waterglass, and further, during the burning a silicate compound which
is extremely favourable for filtration purposes is formed. According as more
or less ground quartz is added, a correspondingly higher pressure can be employed
and thereby a brick of less or more porosity be obtained. By the addition of
organic substances such as saw-dust the porosity may if desired be considerably
increased.
The technical advantages of filter bricks produced by this process are:
uniform porosity and smooth exterior surface, whereby the finest subdivided

page_text: solid substances are retained on the surface and the great danger of choking is
prevented.
The cleaning of such filter plates may also be easily effected by return currents
(back washing) or by re-burning the plates. Pipes made by this process are
especially suitable for filtering purposes on a small scale.
Ground material in the form of sand made from the bricks hereinbefore
described is also valuable as a preliminary filter for retaining the coarser
impurities in water which is to be purified mechanically.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
A process for making porous hard, smooth and acid resisting plates bricks or
pipes with suitable porosity for filtering and the like purposes, characterised by a
mixture of calcined kieselguhr (diatomaceous earth) powdered quartz and soda
waterglass, and if necessary with the addition of organic substances such as
sawdust or the like, being moulded into the desired shapes, compressed and after
the hardening which soon takes place, heated slowly to a clear red heat
substantially as hereinbefore set forth.
Dated this 30th day of June 1896.
W. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.