Abstract: A process for manufacturing a sliding contact piece for medium to high current densities including a step of warm premixing of graphite and plastic binder, a step of cold mixing of the resulting premixture with copper, a step of pressing of the resulting main mixture into the sliding contact piece, and finally a step of sintering of it; and so as to improve the operating characteristics of the sliding contact piece, which is free of any environmentally harmful additives, a metal such as zinc, tin, bismuth or an alloy of such metals is added during the premixing of the graphite and plastic binder.

Abstract: A process for manufacturing a sliding contact piece for medium to high current densities including a step of warm premixing of graphite and plastic binder, a step of cold mixing of the resulting premixture with copper, a step of pressing of the resulting main mixture into the sliding contact piece, and finally a step of sintering of it; and so as to improve the operating characteristics of the sliding contact piece, which is free of any environmentally harmful additives, a metal such as zinc, tin, bismuth or an alloy of such metals is added during the premixing of the graphite and plastic binder.

Abstract: Carbon brush including at least one pressed-in stranded copper wire arranged as a plait-woven hollow stranded wire, formed from a plurality of copper strands of diameter 0.05 to 0.1 mm, and recrystallized by heat treatment. The hollow stranded wire contains at least one stiffening inner wire having a diameter of 0.1 to 0.5 mm, the diameter of the at least one stiffening inner wire being at least twice the diameter of any of the copper strands.

Abstract: The invention relates to carbon brushes for electrical machines with commutator in a vehicle with a 36 volt electrical system. According to the invention, the specific electrical resistance of a carbon brush that can be used in a starter motor is greater than 1,000 &mgr;&OHgr;cm, the specific electrical resistance of a carbon brush that can be used in an auxiliary electric motor or an alternator is greater than 10,000 &mgr;&OHgr;cm, and the specific electrical resistance of a carbon brush that can be used in a fuel pump motor is greater than 20,000 &mgr;&OHgr;cm.

Abstract: A process for fixing a graphite-rich material onto a metallic body by mixing graphite powder with a plastic material to obtain a graphite-rich material, pressing the graphite-rich material onto a layer of a metal-rich material, in a single step, forming thereby a green pressing formed of a graphite-rich component and a metal-rich layer, aligning the green pressing with the metallic body to which it is to be fixed, and subjecting the aligned metallic body and green pressing to a heat treatment to bond the metal-rich layer to the metallic body.

Abstract: An improvement to an electric fuel pump which includes an electric motor with a rotating commutator defining an axial direction, a radial direction and a tangential direction, and having a circumferential surface, and a carbon brush having a contact surface contacting the circumferential surface of the commutator. The brush includes a gap extending from the contact surface in a radial direction and further extending through the brush in the axial direction, the gap reducing flotation of the carbon brush caused by a layer of fuel drawn between the carbon brush and the commutator. In an alternate embodiment, the brush includes a pressure relief hole extending from the contact surface completely through the brush in the radial direction.

Abstract: A membrane comprising a pore-free separation layer, wherein the separation layer consists of poly-dimethyl aminoethyl methacrylate homopolymers or N-vinylpyrrolidone dimethyl aminoethyl methacrylate copolymer or N-vinylcaprolactam dimethyl aminoethyl methacrylate copolymer or N-vinylcaprolactam N-vinylpyrrolidone dimethyl aminoethyl methacrylate terpolymers.

Abstract: A process for manufacturing brushes for electric motors utilizing a female die with two sheaths intersecting at 90.degree. from each other, one sheath vertical and the other sheath horizontal, and each sheath provided with at least one male die and forming a compression cavity. A batch of conductive powder is introduced into the cavity, and a first compression is performed under displacement control using compression means of one of the two sheaths so as to obtain an intermediate tubular cavity having the cross section of the other sheath. A second compression is then performed under pressure control using the compression means of the other sheath so as to obtain a crude brush of final volume at a desired final compression rate. The compression means of each of the sheaths is moved apart, first those under pressure control and then those under displacement control, and the crude brush is ejected.

Abstract: A method for removing C.sub.1 -C.sub.3 alkanols from their mixtures with hydrocarbons or heteroatom-containing hydrocarbons wherein the method comprises utilizing a membrane comprising a non-porous separation layer of cellulose ester containing polymeric materials, characterized in that said polymeric material is a polymer blend of a first polymer selected from cellulose esters and at least one second polymer selected from polyvinyl pyrrolidone (PVP), copolymers of vinyl pyrrolidone and vinyl acetate (VP-co-VA), polyethylene glycol (PEG), N,N,-dialkylated polyacrylic amide (DPAA) and cellulose esters other than said first polymer.

Abstract: A heat exchanger block includes a monoblock composed of a ceramic material having two separate conduit systems for media flowing therethrough. At least one of the conduit systems includes a conduit having a cross-sectional profile of an essentially oblong slot and having a plurality of walls. Each wall has a cross-sectional profile of overlapping circular arcs.

Abstract: Process for the manufacture of composite plasma membranes with the production of a pore-free impermeable polymer layer on a porous substrate through the plasma polymerization of a gaseous mixture, said gaseous mixture containing a hydrocarbon as the matrix-forming component and a nitrogen-, silicon-, sulphur- or phosphorus-containing inorganic compound as the non-matrix-forming component and an oxygen-containing compound, by means of glow discharge in an electrical alternating field. The pore-free impermeable polymer layer is produced directly on a porous substrate without the use of an impermeable intermediate layer, said porous substrate having a pore diameter of less than 100 nm on the side facing the pore-free polymer layer. The composite plasma membranes are used for separating C.sub.1 -C.sub.3 alkanols from mixtures thereof with other organic liquids using the method of pervaporation.

Abstract: The invention relates to a composite membrane with a porous polymer support layer and a polymer top layer, whereby the porous polymer support layer is of polyacrylonitrile (PAN), polyacrylamide, polyetheretherketone (PEEK), polyetherketone (PEK), polysulfon or polyethersulfon, whereas the polymer top layer is a dense layer comprising polyvinyl chloride with selective water permeability. Preferably the membrane is provided with a porous polyacrilonitril support layer and a polyvinyl chloride top layer. Further the invention comprises the application of such a composite membrane for the dehydration of organic solvents using such a composite membrane.

Abstract: A process for the separation of liquid component mixtures by combined pervaporation-vapor permeation with a feed flow in the form of a vapor-liquid mixture being employed and the feed flow being passed from bottom to top as a vapor-liquid mixture over a vertically arranged membrane, so that a permanent thorough mixing of vapor and liquid results, and no stationary liquid film is able to form on the surface of the membrane.

Abstract: A process for reducing the alcohol content of alcohol-containing beverages, in particular of beer or wine, wherein the alcohol is partially or completely removed by way of pervaporation.

Abstract: Composite membrane-for separating water from fluid mixtures containing organic components by means of pervaporation comprising a separating layer of cross-linked polyvinyl alcohol, which has been subjected to a post-cross-linking by treatment with acids acting in the vapor phase on the polyvinyl alcohol layer. The acids are preferably hydrohalic acids, sulfurous acid, sulfuric acid, nitrous acid, nitric acid or acetic acid.

Abstract: A polymer is disclosed which has a betaine structure on at least one side chain. The polymer according to this invention is suitable for use as a material for producing a pervaporation membrane. A process is described for producing the polymer according to this invention whereby betaine groups are introduced into a starting polymer. The betaine groups are introduced into the starting polymer by irradiation of the starting polymer with ionizing radiation and then treatment of the irradiated starting polymer with monomers that are capable of a graft reaction. Monomers that either already contain a betaine function or are capable of forming such a function are used. The betaine can be formed, e.g., by alkylating quaternation of a nitrogen atom present in the monomer if an acid group is introduced simultaneously with the alkylating agent.