Abstract: The invention relates to disc reactors with a large free usable volume which are kinematically self-cleaning, consisting of two or more parallel counterrotating shafts, on which toothed discs with scrapers, which are distributed over their circumference, are disposed, and a surrounding housing. The toothed discs are arranged perpendicularly to the axes of rotation in planes which are echeloned one behind the other such that they mesh with one another.

Abstract: Disc reactors with large free useful volume which clean themselves kinematically, consisting of two or more parallel shafts, rotating in the same or opposite directions, on which are located axially staggered, circular discs with scrapers distributed over their periphery, and an enclosing casing.

Abstract: A carbon- and nitrogen-based catalyst consisting essentially of active carbon or active coke and comprising at least 90% by weight of graphite structures containing at least 10% of pores larger than 100 nm in diameter and having incorporated therein an isocyanate which forms C-N-ring structures, the percentage graphite content being at least 90% by weight. The catalayst is especially effective in the low temperature reduction of nitrogen oxides in waste gases.

Abstract: On a single-screw or multi-screw extruder, the part of the barrel lying between a front plate (1) and end plate (2) bounding the processing unit is subdivided into barrel discs (5) of ceramic materials, which are arranged on at least one guide rail (7). The barrel discs (5) are held together by an anchor (9) fixed on the front plate (1) and end plate (2) and at the same time secured against twisting. In addition, the screw elements (3) within the processing unit between front plate (1) and end plate (2) are also made from the same or from another ceramic material.

Abstract: The isolation of polyarylene sulphides by freeing polyarylene sulphides of the type obtained in customary production processes from adherent water and any other volatile constituents by treating the polyarylene sulphides in screw machines and optionally melting them either simultaneously or subsequently.

Abstract: The discharge apparatus comprises an at least four-shaft screw pump having engaging shafts (1,2,3,4) which rotate in opposite directions in pairs. The viscous product to be processed is caught up over a large area and removed by the screws. A double shaft screw pump is connected downstream of the actual collection zone as a pressure build-up zone. The two center screws (2, 3) of the collection zone merge equiaxially into the screw shafts (2a, 3a) of the pressure build-up zone. The collection zone and the pressure build-up zone are combined into one constructional unit. At least one screw shaft is driven. The resulting high viscosity product strands (7) are caught up by the screws in the collection zone and are moved on into the pressure build-up zone. The double shaft screw pump is used for the build up of a high operational pressure and thus provides the prerequisite for the subsequent connection of further procedural stages.

Abstract: A recording medium with a multicolor high resolution pattern created by layer packs. Pattern-forming layers of the layer packs are successively applied by photolithographic means in a sequence corresponding to a color of the high resolution pattern. The pattern-forming layers of the layer packs are separate from one another on the substrate of the recording medium.The process for producing the recording medium includes applying a photoresist layer to a substrate and developing the photoresist. Pattern-forming layers are successively applied over the whole surface of the substrate in a sequence corresponding to a color. The remaining photoresist and the layers overlying it are removed to leave a sequence of pattern-forming layers on the substrate separate from any adjacent pattern-forming layers.

Abstract: The product which is present in the form of a melt is cooled and thereby crystallized in a double-shaft worm machine which has self-cleaning worm shafts rotating in the same direction. The crystallizing material is continually crushed in a repeatedly cutting manner during solidification and during the subsequent cooling operation, while maintaining the main transporting direction in the worm. In this manner, crystal agglomerates are prevented from forming which have only solidified on the surface, while still containing liquid portions inside. The process is carried out using a worm machine, the worm profile of which is repeatedly interrupted by introducing grooves, so that only small segment ridges remain.

Abstract: A twin-screw machine used for treatment of plastics in which the screw shafts are fitted with eccentrically arranged kneading discs, the clearance .delta. between the kneading discs and the inner wall of the machine housing being greater than the constant clearance s between the particular adjacent kneading discs, and the eccentricity e, which is in each case of like orientation, between the axis of rotation and the central point of the kneading disc being greater than zero and less than half the absolute value of the difference between the housing and disc diameters minus the clearance s.

Abstract: Liquid solutions are evaporated to their setting points and the set material so formed is crushed in a screw machine. The phase conversion from the still viscous state to the flowable crushed solid state is carried out in a single closed housing zone of the screw machine and comprises simultaneous evaporation, setting, crushing and further concentration.

Abstract: The invention relates to a small volume outlet apparatus for multiple shaft screw machines for highly viscous materials at the discharge end of a multiple shaft screw having a sieve changing device arranged in it.

Abstract: A process for the production of thermoplastically processible moulding materials based on vinyl polymers of high chemical and molecular uniformity and having residual monomer contents of less than 0.1 mol % which comprises the steps of:(i) mass homogeneous phase polymerization of at least one vinyl monomer in a stirred continuously charged tank reactor to a conversion of from 25 to 60 mol %;(ii) directly concentrating the syrup consisting of residual monomers and vinyl polymer dissolved therein obtained from step (i) in a spiral tube evaporator at a temperature of from 60.degree. to 250.degree. C. and at a pressure of 100 m bar to 35 bar to obtain a solid content of vinyl polymer of from 40 to 90 mol %;(iii) directly charging the concentrate obtained from step (ii) to the inlet zone of a screw evaporator which consists of at least two sequential zones in order to effect further concentration, in which a first zone at a pressure of from 10 to 300 m bar and at a temperature of from 100.degree. to 250.degree. C.

Abstract: The screw extruder is provided with screw shafts arranged so as to intermesh in pairs and rotate in pairs in the same sense, each screw shaft of a pair containing at least one double or triple threaded pressure build-up section corresponding to that of the other screw shaft. At least part of the pressure build-up sections have at least a ratio of screw pitch t to housing inner diameter d within the range:0.7.multidot.f(h/d, .delta./d, q/nd.sup.3)<t/d<1.8.multidot.f(h/d, .delta./d, q/nd.sup.In which q is the volume throughput of one screw pair, n is the screw shaft rotational speed, h is the thread depth, measured from the screw thread base to the housing inner wall, .delta. is the radial screw clearance between the screw crest and the housing inner wall and f is a function between the above values which is specified in the description.

Abstract: An apparatus for melt-spraying thermally sensitive material of low viscosity comprises a heatable multi-screw extruder having intermeshing, self-cleaning screws of specified clearance between the screws and between the screws and the extruder housing, a heatable pump for delivering molten material from the extruder to a heatable atomizer and a spray tank in which the atomizer is located for cooling and solidifying the melt-sprayed material.

Abstract: Substantially spherical granules of phenacetin are prepared by spraying liquid phenacetin which has been melted without decomposition by means of rapid passage through a melting device in which superheating is minimized. The resultant melt-sprayed granules are superior to crystalline phenacetin in the formulation of pharmaceutical tablets.

Abstract: This invention relates to multi-shaft screw extruders in which the screw shafts are arranged to intermesh in pairs and rotate pairwise in the same sense, each shaft of a pair having at least one double threaded or triple threaded pressure build-up section corresponding to that of the other shaft. This invention also relates to a method of using such an extruder to build up pressure within a material with a minimum pressure build-up section and a minimum power input. The extruder and its method of operation are characterized by the fact that at least a portion of the pressure build-up section satisfies ##EQU1## WHEREIN T IS THE SCREW PITCH, D IS THE INTERNAL DIAMETER OF THE HOUSING, Q IS THE VOLUMETRIC THROUGHPUT OF MATERIAL OF A SCREW PAIR AND N IS THE SPEED OF ROTATION OF THE SCREW SHAFTS AND: ##EQU2## WHEREIN IN TRIPLE THREAD PRESSURE BUILD-UP SECTIONS A = 0.1082;a = 15.316;b = 69.111;Andc = 261.85And in double thread pressure build-up sectionsA = 0.206;a = 8.8212;b = 18.414;Andc = 31.668.

Abstract: The instant invention is directed to the discovery that it is now possible to obtain high quality, elastomeric polyurethanes or polyureas, even when using highly reactive diamines as chain lengthening agents, without the formation of unwanted irregularities, if the mixture of reactants is exposed to a high velocity gradient by means of vigorously mixing kneading elements at an early phase of the reaction while the viscosity of the reaction mixture is still low. Generally, the viscosity is kept between 100 and 1000 poises and preferably between 200 and 700 poises during the action of the high velocity gradient.