referring now to the figures of the drawing in detail and first , particularly , to fig1 thereof , there is shown a top view of a membrane 1 according to the invention . the membrane 1 is in this case fixed to a membrane carrier plate 2 . in this case , a peripheral bead 4 , illustrated in fig1 by a broken line , which is attached to a membrane underside 3 engages into a correspondingly shaped groove 5 on the membrane carrier plate 2 . a multiplicity of bosses 7 as supporting elements for a non - illustrated filter cloth are attached to a membrane surface 6 . the boss interspaces form outflow ducts 8 , through which the sludge can flow out during filtration . the outflow ducts 8 have adjoining them ducts which correspondingly lead further on and are in the form of outflow bores 9 which finally lead the sludge into corner bores 10 formed in the corners of the essentially square membrane carrier plate 2 . the outflow ducts 8 and outflow bores 9 are dimensioned in such a way that even large filtrate quantities are delivered quickly and clogging or blockage by solids and / or crystallizing out are largely avoided . the bosses 7 are bordered by a membrane margin 11 . spaced apart from the membrane margin 11 , on the membrane surface 6 , are disposed plane or planar regions 12 which , as compared with an individual boss 7 , have a larger surface that is not interrupted by an outflow interspace 8 . [ 0044 ] fig2 shows a section through a membrane plate 13 according to the invention that is constructed mirror - symmetrically with respect to its longitudinal center axis 14 . the membrane plate 13 in this case contains the membrane carrier plate 2 and two of the membranes 1 held on opposite sides of the membrane carrier plate 2 . the membrane carrier plate 2 has a thickened membrane plate margin 15 . the membrane plate margin 15 carries , spaced apart from an end face 16 , a peripheral groove 5 having a substantially u - shaped cross section . adjacent to the groove 5 in the direction of the center of the membrane plate 13 , the membrane carrier plate 2 narrows in cross section . as a result , a pressure chamber 17 is formed between the membrane carrier plate 2 and the membrane 1 held on the latter , the membrane underside 3 running substantially parallel to the membrane carrier plate 2 in the non - loaded state of rest . the pressure chamber 17 is connected to the collecting line of a pressure medium by an individual connection by a non - illustrated connecting bush attached to an end face 16 of the membrane carrier plate 2 from outside . the peripheral bead 4 closing off the membrane 1 is of a substantially u - shaped configuration , in the final mounting position a u - bottom 18 runs substantially parallel to a bottom 19 of the groove 5 which bears on the u - bottom 18 . two u - legs 20 of the bead 4 bear simultaneously on groove walls 21 , so that the bead 4 is seated in the groove 5 in the manner of a holding projection . the outer , that is to say end - face lower edge 20 of the holding projection has formed on it a sealing lip 23 . the latter is connected in one piece to the bead material . in the position shown here , the press closing force of a non - illustrated opposite chamber plate prevails , so that the sealing lip 23 , by virtue of its softness , is already pressed completely into the contour of the groove 5 . in the direction toward the end face 16 of the membrane plate 13 , the membrane 1 is closed off by the membrane margin 11 that is seated in a receiving edge 24 , provided for this purpose , of the membrane carrier plate 2 . the membrane margin 11 is closed off toward the membrane surface 6 by a sealing strip 25 that is preferably integrally formed in one piece on the bead material . the sealing strip 25 serves for additional sealing off by a filter cloth 26 resting on the membrane surface 6 , in particular for the elimination of leakages . the filter cloth 26 rests both on the individual bosses 7 of the membrane 1 and on the planar region 12 of the membrane 1 . the planar region 12 is in this case reinforced by a thickening of the membrane material in such a way that the membrane 1 has the same cross - sectional thickness here as in the region of a boss 7 . [ 0048 ] fig3 shows a chamber plate 27 according to the invention that , like the membrane plate 13 in fig2 is constructed mirror - symmetrically about its longitudinal center axis 28 . the chamber plate 27 has a chamber plate margin 29 that , as in the case of the membrane plate 13 , is thickened in a bead - like manner . in the final mounting position , the plate margins 15 , 29 running parallel to one another bear in this case on one another and form a filtration chamber for receiving the suspension . the chamber plate margin 29 has adjoining it in the direction of the center of the chamber plate a sealing margin slope 30 , along the run of which the cross section of the chamber plate 27 narrows , so that a filtration space is obtained between the chamber plate 27 and the membrane 1 of a non - illustrated adjacent membrane plate 2 . furthermore , the chamber plate 27 has disposed in it a sludge inflow that contains an inflow duct 31 . the duct 31 leads from the end face 32 of the chamber plate 27 through the chamber plate margin 29 and the sealing margin slope 30 into an interior of the chamber plate 27 . the duct 31 ends there in a t - shaped end - piece 33 which is closed off by two inflow orifices 34 . the two inflow orifices 34 connect the inflow duct 31 to the two filtration chambers which lie on opposite sides of the chamber plate 27 . the outlet duct 33 in this case extends in the region of the inflow orifice 34 substantially perpendicularly to the longitudinal direction of the chamber plate that runs parallel to the longitudinal center axis 28 . adjoining the region of the inflow orifice 34 in the direction of the center of the chamber plate 27 , the chamber plate 27 has the bosses 7 which , as already known from the membrane 1 , serve as supporting elements for the filter cloth 26 which covers the entire chamber plate surface . in the region of the inflow orifice 34 , the filter cloth 26 is fixed to the chamber plate 27 by a holding flange 35 . to receive the holding flange 35 , the chamber plate 27 has a receiving region 36 that is obtained by a further narrowing of the cross section of the chamber plate 27 . the holding flange 35 and the receiving region 36 are in this case configured in such a way that the surface of the holding flange 35 seated in the receptacle 36 lies in one plane with the surface of the bosses 7 of the chamber plate 27 . finally , fig4 shows part of a plate stack 37 according to the invention , with the membrane plate 13 according to the invention and with the chamber plate 27 according to the invention bearing on the latter . by a press pressure , the two plates 13 , 27 contact one another in the region of their plate margins 15 , 29 , with the result that the bead 4 of the membrane 1 is firmly fixed in the groove 5 of the membrane carrier plate 2 . a filtration chamber 38 is formed between the chamber plate 27 and the membrane 1 of the membrane plate 13 . when , during press filtration , the pressure chamber 17 is filled by a non - illustrated pressure medium connection present in the membrane carrier plate 2 , the membrane 1 presses onto the filter cake in the direction of the chamber plate 27 . the planar region 12 of the membrane 1 is in this case disposed and dimensioned in such a way that , in the case of a sufficiently high pressure , it is laid onto the inflow orifice 34 and at the same time overlaps orifice margins 39 of the latter . a penetration of the membrane 1 into the inlet orifice 34 is thereby ruled out .