Improvements in Filters.
Year: 1893

page_text: Date of Application, 21st Aug., 1893-Accepted, 23rd Sept., 1893
COMPLETE DI POIFIONTIO
Improvements in Filters.
I, HERMANN KOCH, Civil Engineer of Magdeburger Strasse No. 67, Halle
/a Saale in the German Empire 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 :-
Up to the present time no filter has worked quite perfectly, and perfectly pure
water can only be obtained by filtering the dirty water several times in succession.
This invention relates to the manufacture of a filtering material and a construction
of filter for more effectually purifying water.
The filtering material employed consists of specially prepared coke powder
having a filtering action which has not yet been attained by any filtering material.
It is produced by heating coal to a red heat without access of air, that is to say
subjecting it to dry distillation, then, after the heating, quenching with water, and
then washing and drying the product. After drying, the coke is pulverised, and
prepared as follows:-
Three parts of readily fusible caustic alkali, or, it may be also a carbonate of
alkali, are melted, two parts of the ground coke are stirred into the thin fluid mass,
and the mixture is kept for some time with constant agitation at a red heat. After
cooling, the molten mass is pulverised, and the alkali is washed out with hot water.
The residue (the coke) which is still alkaline, is slightly acidified with hydrochloric
acid and water, then washed again till its reaction is neutral, and it is then dried.
The coke thus prepared is then placed in a filter such as is illustrated by the
accompanying drawing, in which
Fig. 1 is a longitudinal section, Fig. 2 is a transvere section;
Referring to Figs. 1 and 2, the filter body proper
cup e.
filtering vessel a.
Figs. 3 and 4 are respectively transverse and longitudinal sections of a
modification.
is fitted into a vessel a open
at the top. This body b is also open at the top, and has a perforated bottom c.
Inside the cylinder b is a second cylinder d which divides the interior of the
filter into two parts accessible from the top. The part of the bottom c whence
the inner cylinder d extends upwards is not perforated. Below this cylinder d is a
A perforated cover e¹ covers the filter body, and a cup a¹ covers the
The water to be filtered enters through the tubular stem f and opening f¹ into
the cup e
The perforated bottom c and also the cover are lined above and
below with filtering fabric g, such as felt, and coke powder prepared as above
described is placed in the filter body b and the cylinder d. The dirty water, which
enters e, flows through the two filtering cloths of the bottom c and rises in the
cylinder d undergoing its first purification. It then passes through the cover e
and its two filtering cloths g, and then down the annular space surrounding d. On
leaving this space, the water is perfectly purified, and collects in the receptacle
below e whence it can be drawn off by either of two apertures h h¹.
Since the water has to pass only by the course described, the several cavities of
the apparatus must be quite separated from one another, communicating only
through the perforated bottom c and cover e¹.
For this purpose, a screw i is screwed into the stem f tightly against its
shoulder, so that the cup e makes a tight joint with the unperforated part of the
bottom c. By tightening the nut f2 on the stem f, the body b is firmly pressed
against the shoulder of the casing a, and the joint can be made tight by a packing
ring j.
The upper cover el is pressed by a nut against the upper edges of band d and

page_text: the cover a is tightened down by the nut ².
When the filtering material has
become spent, or useless, the water contained in the filter must be allowed to run
off. For this purpose a small vent screw k in the cover a¹ is unscrewed allowing
air to enter while the water runs out through h.
In the case of very dirty water, it is preferable to pass the water several times
through layers of coke.
A construction of a filtering apparatus with several filtering layers is illustrated
in Figs. 3 and 4. In this apparatus there are inserted in the filter body B, which
is fitted in the casing A as in the filter shewn in Figs. 1 and 2 three cylinders D
D' D2 which divide the interior into four parts. There is a perforated bottom C,
and a perforated cover E¹. On E' there is placed an inverted dish L which connects
the innermost space with the adjacent annular space.
The cup
E (Fig. 4) under
the bottom C is formed with an inner cup E so that the space between E and E³
puts in communication the two filtering spaces situated between the cylinders D
and D².
The water to be filtered in this case enters by F and F' the inner space of the
cup E2; the water passes through the filtering cloth on both sides of C and the
coke powder in the space within D to the top when it passes again through filtering
cloths into the dish L whence it turns and passes down the space between D
and D to E thence upwards between D2 and D' collecting in the space between
the dish L and the cover A¹; it then flows down through the outermost filtering
space outside D2 to the receptacle at the bottom whence it is drawn off by either of
the apertures HH'.
A screw and nuts as in the apparatus shewn in Figs. 1 and 2 make the required
tight joints.
The two apparatus above described have in consequence of the peculiar action of
the prepared coke powder, in conjunction with the filtering cloths, such an excellent
action that even the dirtiest water is completely clarified.
The arrangement as shewn in the drawings, is only applicable to water which is
under pressure. If it be desired to filter water which is not under pressure, the
apparatus must be so placed that the tubular stem for F is inverted, so that the
water can flow into the apparatus at the top.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. A filter for water, having cylindrical layers of a prepared coke powder,
arranged in such a manner that the water flows through the several layers alter-
nately upwards and downwards, passing through filter cloths from one layer to the
other, substantially as described with reference to Figs. 1 and 2.
2. The modified filter in which there are several cylindrical partitions D, D' D'
and the liquid is caused to flow from one layer to the other by means of a special
dish L and cups E E2, substantially as described with reference to Figs. 3 and 4.
3. A filtering material produced by melting pulverised and washed coke obtained
by dry distillation of coal, with caustic alkali, or carbonate of alkali, pulverising
the melted mass, washing out the alkaline matter, acidulating with dilute hydro-
chloric acid, washing until the powder is neutral and then drying, substantially as
described.
Dated this 21st day of August 1893
ABEL & IMRAY,
Agents for the Applicant.