Filter support of plates for filter presses

A support for the plates of filter presses and filters for filtering over a filter wall, for instance over a filter cloth or filter paper. The support is provided with regularly oriented projections. The upper surfaces of the projections, which are in contact with the filter wall, are provided with grooves.

BACKGROUND OF THE INVENTION 
The invention relates to a support for the plates of filter presses and 
filters for filtering over a filter wall, for instance over a filter cloth 
or filter paper, which filter support is advantageously made of plastic 
material. The draining arrangement of the filter support of the invention 
comprises regularly oriented projections of geometric shapes. 
At present, supports for the plates of filter presses and filters are 
different types of draining arrangements. As a draining arrangement, a 
system of projections supporting the filter wall and a system of channels 
serving for the removal of filtrates between said projections is employed. 
A commonly used draining arrangement uses vertical grooves at both sides 
of filter press plates, particularly wooden filter press plates and plates 
made of polypropylene. Some filter press plates made of plastic materials 
are also provided with inclined grooves, with cylindrical projections and 
projections in the shape of truncated pyramids. Another draining 
arrangement uses truncated pyramids with channels with two different 
depths for the removal of filtrates. 
All of the above-mentioned draining arrangements have the common drawback 
that the surfaces of the projections on which the filter wall bears is 
smooth, flat or slightly convex, and the filter wall bears on this surface 
rather tightly due to the filter pressure. At places where the filter wall 
is in contact with the projections of the draining arrangement, the speed 
of filtration is reduced, such reduction being larger the thinner the 
filter wall is, and the larger the surface of the projections. Recently, 
thinner, hard and rather dense filter walls are used which are made of 
synthetic fibers. These walls are smoothed by calendering them from one or 
both sides in order to make them anti-adhesive to filter cakes. This kind 
of filter wall requires a particularly effective draining arrangement. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a support for the plates of 
filter presses and filters for filtering over a filter cloth or filter 
paper, which passes the filtrate more uniformly over the whole filtering 
surface. The filter support according to this invention is provided with 
regularly oriented projections of geometric shapes, for instance 
cylinders, prisms, truncated pyramids or cones, the upper surfaces of 
which are flat or slightly convex, the upper surfaces of this draining 
arrangement, which are in contact with the filter wall, being provided 
with grooves. 
The filter support according to this invention, with grooves upper surfaces 
of projections of the draining arrangement, permits a good removal of the 
filtrate even from places where the projections are in contact with the 
filter wall. The grooves can extend in one direction, or in two directions 
which are disposed at an acute or a right angle with respect to each 
other. It is possible to have the grooves made in directions which differ 
from the directions of the warp and weft of the filter cloth so that the 
individual fibers of the filter cloth obtain a better support.

DESCRIPTION OF PREFERRED EMBODIMENTS 
The support for the plates of filter presses and filters according to FIGS. 
1 and 2 is provided with regularly oriented projections 1 of the shape of 
truncated pyramids arranged in spaced parallel rows, with channels 3 
between these projections, the channels extending at right angles with 
respect to each other. The pyramids in each row are disposed at a uniform 
distance from each other. The upper surface of the projections 1 of this 
draining arrangement of the filter support is provided with spaced 
parallel grooves 2 extending in one direction. The grooves 2 are at an 
angle of 45.degree. with respect to the same one side of each pyramid. 
These projections 1 of the shape of a truncated pyramid have dimensions of 
8.times.8 mm, a height of 4 mm, the grooves 2 are 0.5 mm wide, and are 0.5 
mm deep. The channels 3 have a depth of 4 mm and a width of 6 mm. 
The support for the plates of filter presses and filters according to FIGS. 
3 and 4 also has regularly oriented projections 1, with channels 3 between 
these projections 1, the projections being disposed in the same manner as 
in FIGS. 1 and 2. The upper surface of the draining arrangement of the 
filter support, which is in contact with the filter wall has two sets of 
grooves 2 extending in two different directions. In the illustrative 
embodiment the grooves 2 in the two sets through extending at right angles 
to each other and at 45.degree., in reverse directions, with respect to 
the channels 3. The dimensions of grooves 2, of channels 3 and projections 
1 of the draining arrangement are the same as in FIG. 1. 
Although the invention is illustrated and described with reference to a 
plurality of preferred embodiments thereof, it is to be expressly 
understood that it is in no way limited to the disclosure of such 
preferred embodiments, but is capable of numerous modifications within the 
scope for the appended claims.