IMPROVEMENTS IN FILTER BLOCKS OR SLABS
Year: 1881

page_text: LETTERS PATENT to Charles Denton Abel, of No. 28, Southampton
Buildings, Chancery Lane, in the County of Middlesex, for an Invention of
"IMPROVEMENTS IN FILTER BLOCKS OR SLABS." A communication from
abroad by Fritz Kleemann, of Schöningen, in the German Empire.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 23rd November 1881.
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane,
in the County of Middlesex. "IMPROVEMENTS IN FILTER BLOCKS OR SLABS."
[A communication from abroad by Fritz Kleemann, of Schöningen, in the German
Empire.]
This Invention has for its object the manufacture of slabs or blocks serving as
filtering medium for liquids with internal passages or channels that are enclosed on
all sides by the material of which the block or slab is composed, and that
consequently serve to facilitate the free flow of the liquid filtering through the
body of the block from its outer surface.
For this purpose the filter blocks or slabs are made by preference of materials
that become hard on being heated to a red heat, such as coke, and other suitable
carbonaceous matter, clay, compounds of burnt and unburnt fireclay, and the like,
mixed with binding materials such as tar, pitch, glue, molasses, saccharine solution,
or flour paste. The solid materials are first ground to powder and then mixed
intimately with the binding material, and the plastic compound thus produced is
then placed in a frame or mould in which it is subjected to pressure. The flat
slabs thus produced are then covered with sand or coaldust and subjected to a red
heat, which is by preference effected in an oven or muffle so arranged that the
flames or gases do not come in contact with the slabs. As soon as the whole of
the carbonaceous matter of the slabs has become completely charred, the slabs are
allowed to cool gradually, and the surfaces having been ground or planed flat, two
such slabs are fitted together with fillets or strips of the same compound inserted

page_text: between thein in such manner as to leave spaces or channels between the strips,
which are first coated with cementitious matter. The compound block or slab is
then subjected to moderate pressure, after which it is heated to a red heat again,
thereby firmly cementing the several parts together, and producing a filter block or
slab having internal channels, but which are still open at two opposite ends. For
closing these the grooves at such ends are somewhat enlarged or bevilled towards
the outer edges, and correspondingly bevilled strips or fillets of the filter compound
are fitted in with the cementing material under moderate pressure, after which the
slabs are again heated. The said closing strips might also be fitted in at the same
time that the internal strips are fitted, so that one heating process suffices for fixing
both sets; or according to another modification the one slab may be formed in the
first instance with projecting fillets or with sunk channels, so that on cementing to
it the other slab and heating, the filter slab with internal channels is formed.
Suitable openings are cut into the said channels for allowing the filtered liquid
to run off.
Existing filter slabs with open internal channels may also be converted into slabs
with closed channels by cementing strips or plugs into the openings.
For this purpose the openings or grooves are by preference enlarged or bevilled
towards the outer edges, and into them are fitted correspondingly bevilled strips of
filtering material coated with cement, which strips do however not fill the depth of
the grooves entirely, so as to form a part thereof into a closed channel
communicating with the other channels. The slab is then heated to a red heat as
in the case of the before described slabs.
If the slabs have the said open grooves at all four sides, the strips for closing
two contiguous grooves may be formed as a single angular strip, thus saving two
joints.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Denton Abel in the Great Seal Patent Office on the
16th May 1882.
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane, in
the County of Middlesex. "IMPROVEMENTS IN FILTER BLOCKS OR SLABS." A
communication from abroad by Fritz Kleemann, of Schöningen, in the German
Empire.
This Invention has for its object the manufacture of slabs or blocks serving as
filtering medium for liquids with internal passages or channels that are enclosed on
all sides by the material of which the block or slab is composed, and that
consequently serve to facilitate the free flow of the liquid filtering through tho
body of the block from its outer surface.
For this purpose the filter blocks or slabs are made by preference of materials
that become hard on being heated to a red heat, such as coke and other suitable
carbonaceous matter, clay, compounds of burnt and unburnt fire-clay, and the like,
inixed with binding materials such as tar, pitch, glue, molasses, saccharine solution,
or flour paste. The solid materials are first ground to powder and then mixed
intimately with the binding material, and the plastic compound thus produced is
then placed in a frame or mould in which it is subjected to pressure. The flat
slabs thus produced are then covered with sand or coal dust and subjected to a red
heat, which is by preference effected in an oven or muffle so arranged that the
flames or gases do not come in contact with the slabs. As soon as the whole of the
carbonaceous matter of the slabs has become completely charred, the slabs are
allowed to cool gradually, and the surfaces having been ground or planed flat two
such slabs are fitted together with fillets or strips of the saruo compound inserted
between them in such manner as to leave spaces or channels between the strips,
which are first coated with cementitious matter. The compound block or slab is
then subjected to moderate pressure, after which it is heated to a red heat again,
thereby firmly cementing the several parts together, and producing a filter block
or slab having internal channels, but which are still open at two opposite ends.
For closing these the grooves at such ends are somewhat enlarged or bevilled
towards the outer edges, and correspondingly bevilled strips or fillets of the filter
compound are fitted in with the cementing material under moderate pressure, after
which the slabs are again heated. The said closing strips might also be fitted in
at the same time that the internal strips are fitted, so that one heating process
suffices for both sets; or, according to another modification, the one slab may
be formed in the first instance with projecting fillets or with sunk channels, so that
on cementing to it the other slab and heating, the filter slab with internal channels
is formed.
Suitable openings are cut into the said channels for allowing the filtered liquid
to run off.
Existing filter slabs with open internal channels may also be converted into
slabs with closed channels by cementing strips or plugs into the openings.
For this purpose the openings or grooves are by preference enlarged or bevilled
towards the outer edges, and into them are fitted correspondingly bevilled strips of
filtering material coated with cement, which strips do however not fill the depth of
the grooves entirely so as to form a part thereof into a closed channel communicating
with the other channels. The slab is then heated to a red heat, as in the case of
the before described slabs.
If the slabs have the said open grooves at all four sides, the strips for closing
two contiguous grooves may be formed as a single angular strip, thus saving two
joints.

page_text: Fig. 1 shews a section, and Fig. 2 a plan of the frame or mould F, into which
the plastic compound herein before described for forming the filter slabs is placed,
and subjected to pressure by the press G, after which it is baked or burnt, as
described, thereby carbonizing the vegetable matter contained therein, and producing
a slab of the requisite degree of porosity. After cooling in a closed chainber the
slabs are rendered level or smooth by planing, grinding, or otherwise, and strips B,
Figs. 3, 4, and 5, prepared of the same material are then introduced between them,
the strips being coated with the same cementing material as was used in the
manufacture of the slabs, and after subjecting the block thus formed to pressure it
is again heated to red heat, whereby the two slabs with the intervening strips will
become united together, forming a filtering slab having a serios of internal channels.
After being allowed to cool very gradually, the internal and external surfaces of
the slab are thoroughly washed with water, and the two open side grooves are
then closed in by similar strips of the filter material, for which purpose the open
grooves C¹ are first cut to the tapering or bevil form shown, and the strips D, D, of
a correspondingly bevilled shape, and coated with cementing material, are then
introduced with slight pressure, leaving a channel at the bottom of the groove, as
shown, after which the slab is for the third time heated to a red heat. In some
cases the strips B and D can be inserted at the same time, or they can be formed
in one with the one slab A, but the first described method is preferable, as
furnishing more perfect slabs. Fig. 3 shows a longitudinal section of the complete
slab, and Figs. 4 and 5 shew respectively cross sections on lines a, b, and c, d.
The degree of porosity of these slabs may be varied at will, according to the
purposes to which they are to be applied, by varying the size of the granules
and the quantity and nature of the cementing material employed in their
composition.
The above described method of producing filter slabs with entirely enclosed
channels may also be applied to existing slabs having internal channels terminating
in open grooves or channels at the ends or sides of the slabs.
Fig. 6 shews a longitudinal section of a slab enclosed in a wood frame, and
having internal channels open on all sides; Fig. 7 shews a cross section of the
same; Fig. 8 shews a longitudinal section of a slab with the channels closed on all
sides, according to this Invention; Fig. 9 shews a cross section of the same; Fig. 10
shews a longitudinal section of the improved construction of filter slab; and Figs.
11 and 12 shew cross sections taken respectively on lines A, B, C, D, shewing the
mode of closing the grooves. As shewn in Figs. 6 and 7, the slabs with open
channels can only be used when they are surrounded on all sides by an enclosing
frame. For this purpose the slab J is placed in the wood or metal frame K, and
is secured therein by running in an easily fusible metal or alloy b all round,
leaving a channel m, as shewn. With this construction it has been found that in
consequence of the different coefficients of expansion and contraction of the slab J,
and the metal b on an increase or decrease of temperature, the joints between the
two will not remain tight, so that the impure liquid will penetrate from without
into the channels m, and thus destroy the action of the filter. This disadvantage
is obviated by enclosing the channels or grooves m with strips of the same material
as the filter slabs according to the present Invention. For this purpose the
grooves m are first bevilled or tapered, as shewn at Figs. 11 and 12, and they are
then fitted with correspondingly bevilled strips x, cemented in. These strips,
although by preference of the same material as the slabs, may however be of a
different material. For the cement may be used tar, pitch, glue, molasses, sugar
solution, starch, or flour paste, with which the surfaces of the strips and grooves
are coated. The strips being pressed in so as to leave a channel m at their inner
ends, the slabs are then heated to redness, so as to carbonize the cement and fix
the strips securely to the slabs, forming practically one piece therewith. The
openings for the discharge of the filtered liquid from the channels are bored
subsequently into the slabs.
The slabs so prepared can be used either with or without a frame, as at Figs. 3

page_text: to 7, being fixed in the frame by running in a fusible metal or alloy, as shewn at
Figs. 8 and 9. The strips for enclosing the four sides of the slab may either all bo
separate, or two contiguous ones may be formed of one piece.
Having thus described the nature of the said Invention, and in what manner
the same is to be performed, as communicated to me by my foreign correspondent,
I claim,-
First. The herein described method of manufacturing filter slabs with entirely
closed internal channels, such method consisting in forming the slabs of pulverulent
or granular carbonaceous matter, clay, or fire clay mixed with a binding material
or cement, consisting of either tar, pitch, glue, molasses, solution of sugar, starch, or
flour paste, the compound being pressed in moulds and then heated to a red heat
under exclusion of the air.
Second. The method of manufacturing filter slabs with entirely enclosed internal
channels by means of two flat slabs of filtering material prepared as described in
the preceding claim, and united together by means of intervening strips of the
same material cemented thereto and then heated to a red heat under exclusion of
the air, substantially as herein described.
Third. The method of closing the outer grooves or channels C by forming them
with taper or bevilled sides, and inserting therein strips D of corresponding taper
or bevilled form previously coated with cement, and afterwards heated to redness
under exclusion of the air, substantially as herein described with reference to the
accompanying Drawings.
Fourth. The method of converting existing filter slabs with open internal
channels into slabs with closed internal channels by inserting into the open
channels or grooves m strips a previously coated with cement, and then heating
the slabs to redness under exclusion of the air, substantially as herein described
with reference to Figs. 10, 11, and 12 of the Drawings.
In witness whereof, I, the said Charles Denton Abel, have hereunto set my
hand and seal, this Sixteenth day of May, in the year of our Lord One
thousand eight hundred and eighty two.
ATTR
ADRE