Filter Element

The invention concerns a filter element, for insertion into the housing of a pressure filter.

Filter elements of this general type are known from German Auslegeschrift DE-AS No. 2 114 226. The filter tubing used therein are provided with several support bodies in the interior. The known filter element with support bodies provides an improvement in filtration characteristics. The mounting of support bodies of more complicated geometry, though, creates difficulties during cleaning of the filter elements by means of flushing-back. The construction of the inserts and the filter elements has also been more expensive and has led to an increase in cost of the filter as a whole.

It is therefore the object of the present invention to provide a filter element which is simple in construction, strong and easy to clean.

This object is attained according to the present invention by a filter element, its support body composed of a bundle of tubes, which is arranged about a central tube.

The densest packing of tubes of equal diameter is provided through arrangement of six tubes about a central tube. In addition, one can use tubes of different diameter for the central tubing. As a rule, the closed surface of the central tubing is a preferred embodiment. The support tubing maintained about the central tube displays openings about their circumference as a particularly advantageous embodiment. In connection therewith, the openings can be formed or cornered, quadratic, rectangular or polygonal. Moreover, tubing with a closed surface can be used to surround the central tube. Synthetic plastics have proven to be particularly suitable material for the tubing. The choice of specific material should be based upon the chemical characteristics of the suspension to be concentrated. Metal tubing is also suitable, the preference for plastics being mainly an economical determination.

The novel features which are considered characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

FIG. 1 is a longitudinal section through a filter element according to the present invention.

FIG. 2 is a cross-section through the filter element.

FIGS. 3, 4 and 5 show different tube openings.

The filter element is composed of a base 1 and a lid 2. Support tubes 4 are arranged about a central tube 3, with the densest packing. The central tube 3 has a closed tube surface. The support tubes 4 can be partially perforated. A filter web 5 is put about the tube bundle to such an extent that during filtration from the outside inwardly a wave-like surface forms, and in the state of washing back a round cross-section is displayed. The filter element can be fixed with a seal 6 into the not shown mounting of a filter tank. The upper opening of tube 4 can be closed by the lid 2; alternatively, there may be an intermediate space between lid and upper edge.

A particularly advantageous refinement of the tube openings involves horizontal slits, which can be produced in simple manner by clamping the filter element upon a turning lathe. Therewith are produced uniformly horizontal openings, for which the spacings and size--or, in the case of round openings, diameters--can be adjusted as desired. Slits with an angle of 120.degree. to the axis have proven to be particularly suitable.

The use of tubing as support elements for a filter web has the advantage that, in simple manner, the web is supported, and the filtrate can flow into the intermediate spaces. it enters at the lower part of the central tube, and leaves the tube through its upper opening into the filtrate space of the filter tank. The flow of filtrate is improved substantially by perforating the support tube.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of bracing differing from the types described above.

While the invention has been illustrated and described as embodied in a filter element, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.