A mouthpiece (10) for extruding a molding compound into a formed body which has internal channels, comprises: a mouthpiece frame (14) with a frame opening (16); a first core retaining plate (22) which is fastened in the area of an upstream end of the frame opening (16) when viewed in the flow direction (15) of the molding compound; and a plurality of longitudinal cores (28) which are axially and laterally held by an upstream end section (26) on the first core retaining plate (22). It is proposed that, furthermore, it comprises a second core retaining plate (36) which is loosely arranged downstream of the first core retaining plate (22) relative to the mouthpiece frame (14) in the flow direction (15), and in which the areas (32) of the cores (28) farther from the upstream end section (26) are arranged to be radially fixed but axially loose.

A valve having a valve housing and a blocking element, wherein the valve housing has a hollow space for receiving the blocking element, an inlet opening for allowing a fluid to flow into the hollow space and an outlet opening for allowing the fluid to flow out of the hollow space, wherein the blocking element has a guide body and is arranged linearly moveably and at least partially in the hollow space of the valve housing between the inlet opening and the outlet opening, wherein the blocking element has at least one opening for allowing the fluid to flow from the inlet opening to the outlet opening via the opening.

Methods for startup of an extruder include (a) initiating feed of a polymer resin to the extruder using a volumetric feeder such that, where the melt index of the polymer resin is less than 10 g/10 min (ASTM D1238 at 230° C., 2.16 kg), the volumetric feeder is operated at a first volumetric feeder speed; or (b) initiating feed of a polymer resin to the extruder using the volumetric feeder such that, where the melt index of the polymer resin is 10 g/10 min or greater, the volumetric feeder is operated at a second volumetric feeder speed greater than the first. The first volumetric feeder speed can range from about 20% to about 25% of the volumetric feeder max speed; and the second volumetric feeder speed can range from about 30% to about 35% of the volumetric feeder max speed.

An apparatus for starting an extrusion process, including at least a drawing device having a main frame, a platform arranged on the main frame, a cable winch arranged on the platform and having a drum, and a wire cable that can be wound up on the drum of the cable winch and pulls an extruded plastics pipe in an extrusion line by way of deflection rolls until the pipe is taken over by a take-off device, wherein the platform is movable transversely to an extrusion direction.

In the manufacture of extruded polymers there are a number of surface defects referred to as sharkskin, snakeskin and orange peel which all generally relate to the rheology of the polymer melt. A severe form of surface defect is “melt fracture” which is believed to result when the shear rate at the surface of the polymer is sufficiently high that the surface of the polymer begins to fracture. That is, there is a slippage of the surface of the extruded polymer relative to the body of the polymer melt. The surface generally can't flow fast enough to keep up with the body of the extrudate and a fracture in the melt occurs generally resulting in a severe loss of surface properties for the extrudate. A polymer extension process is disclosed wherein these undesirable surface defects are eliminated.

A method and apparatus for the pelletization of plastics and/or polymers, in which a melt coming from a melt generator is supplied via a diverter valve having different operating positions to a plurality of pelletizing heads through which the melt is pelletized. The plurality of pelletizing heads have different throughput capacities and are used sequentially for the start-up of the pelletizing process, with the melt first being supplied to a first pelletizing head having a smaller throughput capacity and then the melt volume flow being increased and the diverter valve being switched over such that the melt is diverted by the diverter valve to a second pelletizing head having a larger throughput capacity.

A system for adjusting a gap in a slot die for producing a polymeric web. The system includes a slot die that has a polymer reservoir that extends between a polymer inlet and a melt outlet. The melt outlet has a first edge and a second edge that each extend longitudinally along the melt outlet. The second edge is opposite the first edge. A plurality of actuators move the second edge along a plurality of positions along a length of the second edge. The first edge is spaced apart from the second edge by a gap that has an adjustable profile. A pressure sensor communicates with the reservoir and measures the pressure of the polymer in the reservoir. A control unit with an algorithm correlates the profile of the gap to the pressure in the reservoir. The algorithm is configured to generate control signals to cause the profile of the gap to be uniform.

A method for starting up a production line for manufacturing extruded plates, wherein an extruded semi-finished product comprising a free end is pressed towards a conveying device, wherein the conveying device is configured to pull the semi-finished product to a separating device, wherein a conveyor belt extending in the conveying direction is placed on the conveying device, the free end of the semi-finished product is pressed onto the conveyor belt, the conveyor belt is pulled together with the semi-finished product towards the separating device, and the free end of the semi-finished product arriving at the separating device is introduced into the separating device, while the conveyor belt is pulled away from the semi-finished product upstream of the separating device. This enables a cost-effective production of panels made from the plates.

A system for adjusting a gap in a slot die for producing a polymeric web. The system includes a slot die that has a polymer reservoir that extends between a polymer inlet and a melt outlet. The melt outlet has a first edge and a second edge that each extend longitudinally along the melt outlet. The second edge is opposite the first edge. A plurality of actuators move the second edge along a plurality of positions along a length of the second edge. The first edge is spaced apart from the second edge by a gap that has an adjustable profile. A pressure sensor communicates with the reservoir and measures the pressure of the polymer in the reservoir. A control unit with an algorithm correlates the profile of the gap to the pressure in the reservoir. The algorithm is configured to generate control signals to cause the profile of the gap to be uniform.

An apparatus for starting an extrusion process, including at least a drawing device having a main frame, a platform arranged on the main frame, a cable winch arranged on the platform and having a drum, and a wire cable that can be wound up on the drum of the cable winch and pulls an extruded plastics pipe in an extrusion line by way of deflection rolls until the pipe is taken over by a take-off device, wherein the platform is movable transversely to an extrusion direction.