Abstract: A magnetic dispersion comprising finely divided iron power or iron alloy powder having a BET value of more than 35 m.sup.2 /g dispersed in a polymeric binder and organic solvent, whose filterability is markedly improved, is obtained by using certain low molecular weight phosphoric esters of the general formula I or II ##STR1## combined with a dispersion-active compound which contains at least one polar group capable of adsorption on the magnetic pigment. The polar group of the dispersion-active compound can be an acid or alkaline or amphoteric group or a group capable of hydrogen bonding or polarization. The dispersion-active compound can be a polycondensate, a polyaddition product or a chain growth copolymer which can also be used in the magnetic dispersion combined with customary other polymeric binders.

Abstract: A filter apparatus is described, in which there are in the interior of a filter housing (7) a multiplicity of filter elements (1) which are suspended on the filter cover (3) and in which the inner bores of the filter cartridges are connected to the outlet nozzle (6) via a system of channels. Against the wall of the filter housing (7) there bears a film bag (2), the upper end of which is welded to an O-ring (4), which is seated in an annular groove on the flange of the filter housing, with the diameters of O-ring and film bag being identical. Furthermore, volume displacers (16, 17, 25), which extend in the axial direction over the entire length of the filter housing, are provided between filter bag (2) and inner wall of the filter housing as well as in the inner space of the filter cartridges. When a filter is changed, these volume displacers are, for example, inflated with compressed air, as a result of which the volume of residual filtrate is considerably reduced, so that less loss of dispersion occurs.