Abstract: The invention concerns a process and apparatus for the coextrusion of rubber mixtures, comprising a main extruder (1) with an extrusion head (10) having at least two flow channels (14, 15), each for a rubber mixture (A, B), the channels opening into an extrusion orifice (18) through which the two rubber mixtures (A, B) are propelled. The extrusion orifice (18) is delimited by a first wall (111) and a second wall (161). The apparatus also comprises at least one micro-extruder (2) for a third rubber mixture (C), whose extrusion head (22) is provided at its end with a nozzle (23) passing through the two flow channels (14, 15) such that the third rubber mixture (C) is inserted into each rubber mixture (A, B) upstream from the extrusion orifice (18).

Abstract: The invention concerns a process and apparatus for the coextrusion of rubber mixtures, comprising a main extruder (1) with an extrusion head (10) having at least two flow channels (14, 15), each for a rubber mixture (A, B), the channels opening into an extrusion orifice (18) through which the two rubber mixtures (A, B) are propelled. The extrusion orifice (18) is delimited by a first wall (111) and a second wall (161). The apparatus also comprises at least one micro-extruder (2) for a third rubber mixture (C), whose extrusion head (22) is provided at its end with a nozzle (23) passing through the two flow channels (14, 15) such that the third rubber mixture (C) is inserted into each rubber mixture (A, B) upstream from the extrusion orifice (18).

Abstract: Method and apparatus for minimizing steam consumption in the production of pulp used for the manufacture of fiberboard and the like, in which chips of cellulosic material are ground in a defibrator or refiner in an environment of saturated steam above 100.degree. C and corresponding steam pressures. The chips are normally presteamed with atmospheric steam separated from the pulp at the discharge end of the defibrating process to a temperature between 90.degree. C and 100.degree. C and compressed and dewatered to a dryness of at least 50% and then passed into a preheater which forms part of the defibrating or refining apparatus, where the compressed and dewatered chips are heated to the desired defibrating or refining temperature, usually ranging between 130.degree. C and 200.degree.

Abstract: An improved method for the manufacture of wood fiberboard according to the wet system with a closed white water system includes the steps of drying the incoming lignocellulose containing material, prior to the dilution step, to a dryness, or solid consistency, which is higher than the dryness of the wet lap or sheet before final drying to produce the fiberboard product. Formaldehyde is added to the resulting white water which is homogenized to atomize occurring precipitations through efficient agitation and dispersion prior to being recirculated for use for diluting the incoming fiber material. Thus, there is obtained an efficient closed white water system which results in a reduction of environmentally harmful discharge of polluted water as well as the production of fiberboard with enhanced appearance.

Abstract: An improved method for the manufacture of wood fiberboard according to the wet system with a closed white water system includes the steps of drying the incoming lignocellulose containing material, prior to the dilution step, to a dryness, or solid consistency, which is higher than the dryness of the wet lap or sheet before final drying to produce the fiberboard product. Formaldehyde is added to the resulting white water which is homogenized to atomize occurring precipitations through efficient agitation and dispersion prior to being recirculated for use for diluting the incoming fiber material. Thus, there is obtained an efficient closed white water system which results in a reduction of environmentally harmful discharge of polluted water as well as the production of fiberboard with enhanced appearance.