Abstract:
A method for sintering tube pre-forms in an furnace for obtaining ceramic tubes which are extremely straight is provided, in which, during sintering, the tube preforms are placed inside supporting tubes in ceramic material, the support tubes 1 containing the tube preforms being arranged parallel to each other forming stacks 7 of layers 3 supported by support plates 4 in a refractory material, the inside surface of the support tubes being out-of-true by less than 0.1 mm over a length of 90 mm.
Abstract:
A membrane for a filter device or a device for gas or liquid separation, the membrane being constituted by a porous structure made of at least one material selected from sintered ceramic, sintered metals, microporous carbon, microporous glass, and polymers, said structure including at least one microporous layer, wherein the entire outside surface and inside surface of the pores of said structure is covered by a thin and continuous film of a polyphosphazene, the thickness of said film lying in the range 0.01% to 10% of the mean diameter of the pores of said microporous layer.
Abstract:
A membrane for a filtration, gas or liquid separation or pervaporation apparatus comprising at least one porous layer of an inorganic material selected from sintered ceramic, sintered metal, sintered glass or carbon and a separating layer of organic material, the membrane being characterized in that said organic material is a polyphosphazene, in that the average diameter of the pores in said porous layer of inorganic material is between about 5 nm and 1 .mu.m, and in that said separating layer is continuous and only penetrates into said porous layer to a depth of less than five times the diameter of said pores in said porous inorganic layer, said layers being strongly bonded to each other.
Abstract:
A filter module comprises a plurality of parallel substantially tubular filter elements each of which comprises a ceramic support. Two apertured end plates are attached to a protective casing and each filter element is fixed via flexible seals into respective apertures in these end plates. The module is assemble by a method which begins with molding the blanks from an elastomer material that is resistant to organic solvents and to corrosive liquids and has a Shore A hardness between 30 and 95 and an elastic elongation per unit length in excess of 10%. Each blank can have any form of outside surface and has an internal cavity with a surface matched to the ideal external shape of a filter element, except that its dimensions are slightly smaller than the corresponding dimensions of the filter element. The resulting blanks are then fitted onto the ends of the filter elements. The outside surfaces of the blanks are then machined to match them to the shape of the openings in the end plates, so producing the seals previously mentioned. The filter elements are then fitted into the casing between the plates in such a way that the seals are held in compression between the elements and the plates.
Abstract:
The present invention relates to a module for filtering, separating, purifying gases or liquids, or for catalytic conversion, comprising:- a substantially cylindrical housing (13),- at least one rigid element (4) of which at least one end (5) is substantially cylindrical and whose axis is parallel to that of the housing (13),- at least one elastically deformable metal part in the form of a ring (6), fixed firstly to the housing (13) and connected secondly to said end (5) of said element (4), characterized in that the joint between said ring (6) and said end (5) of said element (4) is a hoop fitting.
Abstract:
The filter membrane comprises a porous structure made of a material selected from sintered ceramics, sintered metals, microporous carbon, and microporous glass, and is characterized by the fact that its entire external surface, including the inside surface of the pores in the structure, is covered with a thin and continuous film of carbon or of an oxide. In a sintered aluminum membrane, the surfaces of pores are coated with a dense and continuous thin layer of zirconia which prevents the surfaces from being degraded in service. In the figure, curve 3 shows how the throughput of a membrane without a zirconia layer falls off over time, while curve 4 shows little change in the same membrane having such a layer.
Abstract:
A filter membrane for filtering liquid food stuffs or hot gases and including at least one filter layer. The membrane is constituted by a sintered inorganic material comprising grains which are fixedly connected to one another and the average roughness of the surface of said filter layer over a distance along said surface equal to at least five times the average grain size is less than one fifth of the average grain size in the region in question.
Abstract:
A method of making imprints on the walls of portions of a tube obtained by the continuous molding of a ceramics-based paste and the cutting up of the tube, wherein immediately after the tube portions have been molded and are still deformable, they are placed on means parallel with the axis of the tube portions for rotating them around their axes of revolution, means are applied to the rotary means for exerting a pressure on at least a portion of the tubes so that such portions are clamped between the rotary means and the pressure-exerting means, the pressure-exerting means or the rotary means are provided with at least one imprint-making tool, the or each tool having a main direction which does not coincide with the direction of the axes of revolution of the tube portions, and means are applied to create a second relative movement between the tube portion and the or each tool, so that there is substantially no sliding between the tube portion and the or each tool. The tubes are useful in gas diffusion processes.
Abstract:
This invention concerns a cellular, spherical bead of organic, macromolecular polymer material which when carbonized in the solid state retains its original beaded shape and has a high carbon content and methods for making such beads of polymer and carbon.