Techniques recycle plastics in multiple successive process steps. A polymer, preferably a recyclable material, is melted using a discharge extruder, filtered using a first filter device under a positive pressure atmosphere, filtered and degassed using a degassing device, and discharged using a discharge extruder. The degassing device has at least one filter element and a vacuum chamber with a negative pressure atmosphere for filtering and degassing purposes, wherein the plastic melt can be conducted into the negative pressure atmosphere of the vacuum chamber through the filter element.

Techniques recycle plastics in multiple successive process steps. A polymer, preferably a recyclable material, is melted using a discharge extruder, filtered using a first filter device under a positive pressure atmosphere, filtered and degassed using a degassing device, and discharged using a discharge extruder. The degassing device has at least one filter element and a vacuum chamber with a negative pressure atmosphere for filtering and degassing purposes, wherein the plastic melt can be conducted into the negative pressure atmosphere of the vacuum chamber through the filter element.

A system and method of regulating a pressure of a fluid with a valve block having a valve block inlet in fluid communication with an outlet of an extruder and a valve block outlet in fluid communication with a die. A transducer in fluid communication with the flow channel and in signal communication with a controller of the motor can sense a pressure and communicate the pressure to a controller of a motor. The motor can adjust a position of a valve to regulate the pressure of the fluid.

The invention relates to a method and a device for introducing and/or adding non-dry-powder additive materials and/or coating materials with a liquid, solid, semi-solid, or paste-like consistency or in suspended or emulsified form, for example, peroxides, fats, waxes, IV improvers, polymers, or similar materials, to an existing lumpy or particulate material which is moved and mixed, and optionally warmed and reduced to small pieces in a receptacle and/or compressor (1), said material being in particular polymer particles and/or flakes, wood fibers, paper cuttings, or similar materials. According to the invention, the additive material is introduced below the level of the material and/or material particles already in the receptacle (1).

The invention relates to a dirt precipitator (100) for a highly viscous medium, having a housing comprising a front housing element (30; 30) that comprises at least one inlet channel (33) and a rear housing element (20) that comprises at least one outlet channel (23), and having a screen wheel (10; 10) rotatably mounted between the housing elements (20, 30; 30) having a number n of screen positions disposed in a ring zone, on each of which at least one screen opening (11.1, . . . , 11.12) having at least one screen insert element is provided. The inlet channel (33), the outlet channel (23), and the screen opening (11.1, . . . , 11.12) are disposed flush one after the other in at least one working position and form a flow channel. In all positions of the screen wheel (10; 10), more than 50% of the screen openings (11.1, . . . , 11.12) are always able to be permeated, and are impinged by flow from at least one inlet channel and from which at least one outlet channel leads.

The invention relates to an extruder for processing pulverulent bulk material, in which at least one housing portion, which accommodates a filter element (5) located on a support frame (4), is configured in a feed region. According to the invention, the filter element (5) is formed from interconnected layers of sintered metal wire mesh screens, the filter element (5) containing at least one protective layer (27) which is directed against the screw and has a mesh size of 20-100 m, a filter layer (28) having a mesh size of <1 m, and a rear support layer, and the protective layer (27) being located at a safety distance of 0.5-2 mm from the outer diameter of the screw. The filter element (5) can be removed from the housing portion with the aid of the support frame (4) and is self-supporting and dimensionally stable.

The invention relates to an extruder for processing pulverulent bulk material, in which at least one housing portion, which accommodates a filter element (5) located on a support frame (4), is configured in a feed region. According to the invention, the filter element (5) is formed from interconnected layers of sintered metal wire mesh screens, the filter element (5) containing at least one protective layer (27) which is directed against the screw and has a mesh size of 20-100 m, a filter layer (28) having a mesh size of <1 m, and a rear support layer, and the protective layer (27) being located at a safety distance of 0.5-2 mm from the outer diameter of the screw. The filter element (5) can be removed from the housing portion with the aid of the support frame (4) and is self-supporting and dimensionally stable.

A tube including a tetrafluoroethylene/fluoroalkyl vinyl ether copolymer, where the copolymer has 500 or less functional groups per 10.sup.6 carbon atoms; the copolymer has a melting point of 280 to 315 C.; the copolymer has a fluoroalkyl vinyl ether unit content of 3.0 to 12.0 mass % based on total monomer units; the copolymer has a melt flow rate of 1 to 15 g/10 min; the tube releases, from an inner surface thereof, 3500 or less particles per 1 cm.sup.2 of the inner surface of the tube; and an amount of total organic carbon eluted with water from the inner surface of the tube is 50 ng or less per 1 cm.sup.2 of the inner surface of the tube.

A method for operating a filter device for polymer melt to be filtered, said filter device incorporating at least one first large-area filter, which has a plurality of filter elements, in a first filter chamber; and a first drain for the filtered polymer melt from the first filter chamber. The polymer melt to be filtered is conveyed under pressure through the filter device. The polymer melt to be filtered is fed to the first large-area filter in the filter direction, and filtering is continuously performed via the first large-area filter. During a backflushing operation, at least one filter element is cleaned of impurities and backflushed by reversing the flow direction of the filtered polymer melt and passing it through the filter element.

A method for operating a filter device for polymer melt to be filtered, said filter device incorporating at least one first large-area filter, which has a plurality of filter elements, in a first filter chamber; and a first drain for the filtered polymer melt from the first filter chamber. The polymer melt to be filtered is conveyed under pressure through the filter device. The polymer melt to be filtered is fed to the first large-area filter in the filter direction, and filtering is continuously performed via the first large-area filter. During a backflushing operation, at least one filter element is cleaned of impurities and backflushed by reversing the flow direction of the filtered polymer melt and passing it through the filter element.