Improvements in Filters.
Year: 1898

page_text: Date of Application, 24th Mar., 1898-Accepted, 25th June, 1898
COMPLETE SPECIFICATION.
Improvements in Filters.
I, CHARLES ABRAHAM, of Kiew, in the Empire of Russia, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement: -
:
Filtering apparatus as at present employed and in which a granular material,
for instance sand, is used, have, with the exception of devices of a very compli-
cated construction, the disadvantage of necessitating such extensive arrangements,
that their applicability is very limited and that the granular filtering substances
are in many cases to be substituted by substances of a more expensive nature such
as fabrics and the like. These disadvantages are removed by the present inven-
tion relating to a universal filtering apparatus, the construction of which admits
of very extensive filtering surfaces being produced in a comparatively small space.
Filtering apparatus of this improved kind essentially consist of box-shaped
receptacles, in which, plates, roofings, diaphragms or gratings of various shapes
are so arranged in various positions, that after they are covered or charged with
granular filtering material, free spaces, chambers and channels are formed, one
or several sides of which are limited by open sloping surfaces, formed by the
filtering material. One portion of these chambers and channels receives the
liquid to be filtered; while another portion serves for discharging the filtered
liquid.
In the accompanying drawing,
Figure 1 represents in cross-section and plan, respectively, a box, in which step
shaped rows of plates a and b are arranged obliquely and so that both ends meet
the transverse walls of the box. Above these plates, wider diaphragms B C,
A B C and A B are provided. When a granular filtering material is thrown in
from above, a row of vertical layers presenting a considerable surface of filtering
material, is formed, while at the same time free intermediate spaces M and N
are produced. On then charging these spaces or chambers M with the liquid to
be filtered, the latter passes as filtered matter into the chambers N and thence to
the outside through special openings. If the filtering material becomes clogged
up, it is discharged through manholes (), arranged at the bottom, and fresh
material substituted, after the apparatus has first been cleansed by rinsing.
Figure 2 represents a cross section and a plan respectively of a circular filter.
a bed and a b₁₁ are truncated-conical surfaces, the former presenting their
apices downward and the latter upward. A B C is a complete conical surface,
BCA B a truncated-conical surface, the upper part of which is in complete con-
tact with the filter-casing. The whole system of cones is fixed by special frames,
which are not represented, in order that the clearness of the drawings may not
be impaired. The layers of filtering material in this case are of annular shape.
The liquid is introduced into the free outer space and is discharged through the
central space. In a box of this kind evidently also a number of such annular
systems may be arranged, several systems may even be arranged concentrically.
In certain cases it is advisable that the hollow spaces, formed by plates and roof-

page_text: ings should alternate with chambers, which are limited by sieves, fabric or porous
plates, in which case the former only receive the arriving liquid, while the latter
receive the filtered matter. The sieves and the like in this case solely serve to
maintain the granular material in a certain position, and as they come only in
contact with purified liquid, they are not subject to becoming clogged.
Figure 3 represents by way of example, a cross sectional view of a box, in
which roof or gable-shaped shields of any suitable form a b c (or a¹ b² c², a¹¹ b¹¹¢¹¹
or the like) are arranged, while between them sieve-shaped prisms (m n) or
cylinders (mn), covered with fabric, are provided. After the box has been pro-
perly charged with sand or other suitable filtering material, free spaces, limited
at two sides by the open top surface of the granular material are retained below
the shields or roofings. The liquid passed into these hollow spaces, traverses
the filtering material, enters the sieve-shaped prisms m n (or cylinders m¹ n¹)
and is thence discharged.
Figures 4 and 5 represent two combined halves of two essentially identical
filters, the arrangement being such that, according to Figure 4, roof-shaped
shields a bc, provided with openings at b, are covered over at the top with
shields A B C, having no openings. At the right and left hand of the box only
halves of shields or diaphragms of the same kind are arranged. Between each
two vertical systems of such shields or diaphragms a chamber P Q is formed by
means of sieves or fabric stretched out upon frames. The liquid enters the hollow
spaces at below the shields, traverses the granular material, enters the sieves
of chamber PQ and is thence discharged to the outside by special spouts or out-
lets. The device shown in Figure 5 only differs from that represented in Figure 4
inasmuch as the shields or diaphragms are located horizontally with the exception
of the lowermost.
In conformity with the type shewn in Figures 4 and 5, circular filters may like-
wise be constructed. Such circular filters would for instance be formed, if the
conical surfaces a¹¹ in Figure 2 were substituted by a continuous cylin-
drical sieve.
All the described filters may be so constructed, that the shields admit of their
being readily removed either separately or in sets; the filters may also be con-
structed analogous to filter-presses; Figure 6 representing, for instance one out
of many possible constructional devices of this kind. In this instance, within the
frame AB, frames P Q with stepped gratings, as described, and sieves R S are
arranged. The liquid to be filtered enters, in the known manner, (by way of a
longitudinal channel traversing all frames) the hollow spaces which are retained
between each two frames PQ, penetrates the filtering layers at the right and left
and is discharged from the sieve chambers R S through openings. For the pur-
pose of cleansing the apparatus, the frames A B are drawn apart, the frames P Q
removed, the filtering material rinsed out and, after the frames P Q having then
again been put in place, fresh filtering material is introduced by means of a feed
device.
In all the filtering devices described, the liquid is filtered only once; filtering
apparatus obtaining a repeated filtration may, however, likewise be constructed
on the same principle. Thus for instance in the case of the filter, represented in
Figure 1, the liquid solely passed into the central space N may be caused to tra-
verse two layers, one at the right and one at the left, and be subsequently dis-
charged through lateral spaces N. In this case each filtering layer may be
exchanged separately and independently of the others.
Instead of the soiled filtering material being exchanged, it may be simply
rinsed out of the apparatus by causing a liquid current to act in the inverse direc-
tion upon the filtering layers and by causing the rinsed out impurities together
with any filtering material that may be carried away, to pass off through special
conduits. The filtering material may also, in a continuous manner, be drawn off
and conveyed into a receptacle communicating with the filter, this being effected
by helices or other conveying devices, arranged below the filtering layers; in this

page_text: case the filtering material would be replaced from above, in proportion as it is
discharged, through the medium of feed-hoppers, so as to settle down automati-
cally. The soiled material may then be automatically passed to a suitable place
for re-purification.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:
-
1. A filtering apparatus, characterized by a casing of any appropriate shape, in
which plates, diaphragms shields, gratings and the like are arranged in various
forms and positions in such a manner, that, after having been covered or charged
with a granular filtering substance, free spaces, partly limited by the sloping
surfaces of the material, are retained, for the purpose of producing as large a
filtering surface as possible in a limited space.
2. In filtering apparatus of the kind ascertained in the First Claim, the method
of and means for substituting a portion of the elements forming the hollow
spaces, by chambers, which are limited by sieves, fabrics or other porous surfaces.
3. The method of connecting the filtering-devices, ascertained in the First and
Second Claims, as in filter-presses.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.