Abstract: The invention concerns the use of a microporous membrane constructed of polyether sulfon and a hydrophilization agent having a pore size which is within the range of between 0.1 and 1.2 microns for the filtration of beer. This membrane filter proves to be particularly suitable for the microbiological stabilization of the beer and for the separation of the turbid substances. The membrane makes it possible to remove the germs which are harmful to the beer and the harmful turbid substances and to simultaneously filter the beer with a high throughput and therefore economically and with low costs.

Abstract: The porosity of a strip of material is continuously computed by causing air to be drawn through the material as the strip moves across a perforated head situated atop a chamber in which the pressure is reduced by suction. In one embodiment, the reduced pressure is held substantially constant while the amount of air drawn through the chamber is measured and the porosity is determined by a computer whose inputs include the measured volume of air flow through the chamber and the speed at which the strip moves across the head, in addition to other inputs. In another embodiment, the volume of air flowing through the chamber is held substantially constant while the pressure in the chamber is measured and used as an input to the computer. In both embodiments, the speed at which the strip moves across the head is employed as a factor in the porosity computation.

Abstract: The invention relates to a measuring head for measuring the porosity of a moving strip of porous material. The measuring chamber of the measuring head is covered by a measuring plate in which measuring openings are provided. For porosity measurement, air is sucked in through the porous strip and the measuring openings into the measuring chamber. The amount of air flowing into the measuring chamber is measured by a measuring arrangement connected to the measuring air connector and serves as a measure of the porosity of the strip. The measuring plate is surrounded by a guide plate which partially overlaps a blowing ring. The guide plate and blowing ring together form a blowing slot surrounding the measuring plate, the blow-out opening of which is directed outwardly and tangentially to the lower surface of the moving strip. The necessary blowing air is introduced via a connector into an annular channel, which is formed from a semi-circular groove in the blowing ring and merges into the blowing slot.

Abstract: A multilayer filter material is described which comprises a coarse and a fine filter layer, while the individual filter layers contain a share of natural fibres and are interconnected with each other on the paper machine, without the use of a bonding agent, whereby the coarse filter layer consists of a mixture of natural and synthetic fibres and at least one part of said synthetic fibres is structured, and synthetic fibres lying on the surface of the coarse filter layer protrude from the plane of the filter material.Moreover a process for the manufacture of the multilayer filter material and its use is described.The inventive multilayer filter material is distinguished against comparable conventional filters by an increased service life and a better degree of separation.