Abstract: A module for crossflow filtration, a method of making same, and a filtration device that accommodates at least one such module, which includes at least two multilayer filter units which are stacked on top of one another and are separated from one another by a respective spacer, with the module having at least one channel for unfiltered material and at least one filtrate channel that connects the filter units. The module further comprises a sealing material ring for sealingly interconnecting peripheral portions of the filter units, with at least one edge section of the filter units being spaced from the sealing material ring to form the channels for unfiltered material. The layers of each individual filter unit are fused together at least at edge sections that are not embedded in the sealing material ring which, at edge sections of the filter units that are embedded therein, has a width that is sufficient to completely accommodate the filtrate channels.

Abstract: A filter element for a filter cartridge has an upstream or prefiltering membrane with frustoconical pores converging in the direction of liquid flow through the filter element and a final filtering membrane at the downstream side with cylindrical pores smaller than the smallest diameter of the frustoconical pores.

Abstract: A filter sheet which is free of asbestos, and which contains cellulose, filtering aids such as diatomite, perlite, etc., and cationically modified material in the form of cellulose on which are chemically bound cationic chemical groups having a degree of substitution between 0.01 and 0.05. The rate of flow and the clarity effect are correlated to the degree of substitution of the utilized cationically modified cellulose, and the pigment adsorption, i.e. the adsorptive properties of the filter sheet, are correlated to the percent by weight of the cationically modified cellulose to the total amount of cellulose contained in the filter sheet. By utilization of these correlations, modified asbestos-free filter sheets can be produced which are adapted to given applications.

Abstract: A filter element that includes a membrane which is to be detachably or non-detachably retained between fixed parts of a filter device, and which is provided on at least one of its sides with a permanently applied strip of sealing material. The strip projects relative to the surface of the membrane at that side, and extends over the entire length which is to be sealed. This sealing strip is thus a permanent part of the filter element. The sealing strip can be arranged directly at the rim portion of the membrane, and can at least partially encompass this rim. The provision of sealing strips so that they are opposite one another on both sides of the membrane is particularly advantageous. The sealing material can be applied in a flowable state, and can be subsequently cured to an elastomeric state. A particularly secure connection between the membrane and the sealing strip or strips may be achieved by penetration of the sealing material into the membrane.