A tube forming apparatus for forming polymeric tubing includes a housing between rear and discharge ends. The tube forming apparatus includes a core tube assembly with an exterior core tube and an inner core tube positioned partially therein and in an interior area of the housing. The tube forming apparatus includes a die that has an inner die-surface. A diverter tip is mounted in and extends from the inner core tube into the die forming a die opening between the die and the diverter tip. The tube forming apparatus includes a core tube adjustment system mounted proximate the rear end which includes an axial displacement device configured to axially position the core tube assembly for modulating wall thickness of the tube and/or an angular displacement device configured to modulate the inner core tube for modulating concentricity of the tube.

A filament is fed to an extrusion head. The filament has a semi-crystalline polymeric reinforcement portion and a polymeric matrix portion. The reinforcement and matrix portions run continuously along a length of the filament. The reinforcement portion has a higher melting point and a higher crystallinity than the matrix portion. The temperature of the filament is raised in the extrusion head above the melting point of the matrix portion but below the melting point of the reinforcement portion so that the matrix portion of the filament melts within the extrusion head, thereby forming a partially molten filament within the extrusion head. The partially molten filament is extruded from the extrusion head onto a substrate, the reinforcement portion of the partially molten filament remaining in a semi-crystalline state as it is extruded from the extrusion head. Relative movement is generated between the extrusion head and the substrate as the partially molten filament is extruded onto the substrate in order to form an extruded line on the substrate. The matrix portion of the extruded line solidifies after the extruded line has been formed on the substrate.

A filtering device for removing dirt particles and contaminants from a plastic melt is disclosed. The filtering device includes a housing having a filter chamber, an inlet for feeding plastic melt, an outlet for channeling plastic melt out, and a dirt outlet for discharging dirt particles from the housing. The filtering device also includes a filter element arranged in the filter chamber to retain any dirt particles contained in the stream of melt, and a cleaning unit for cleaning the filter element of dirt particles retained by means of the filter element. The cleaning unit having a cleaning head with a scraper member for detaching dirt particles from the filter element. The scraper member is coupled to a servomechanism to press the scraper member onto the surface of the filter element. The servomechanism has at least one bellows cylinder including a foot section, a head section, a deformable bellows element, and a pressure chamber of variable volume.

Described is a coextrusion head (1) comprising a plurality of infeeds (11, 12, 13, 14, 15) for fluid products, an inner joining space (16, 17), positioned downstream of said infeeds and communicating with them by means of respective delivery ducts (110, 120, 130, 140, 150) so as to allow flows of products to converge there and an outfeed (18) for the final multi-layer product, positioned downstream of the inner joining space (16, 17). In the head (1) there is a central delivery duct (110), provided for receiving a first flow of product and two lateral delivery ducts (120, 130), designed to receive, respectively, a second flow of product and a third flow of product. The head (1) also comprises adjustable narrowing means (31, 32), acting at least in the central delivery duct (110) and designed to vary a respective opening, to allow adjustment of the relative position of the first flow relative to a composite secondary flow defined by the joining of the first, second and third flow in the joining space (16) .

Provide is a blown film forming apparatus including a die including a columnar inner peripheral member and a cylindrical outer peripheral member that surrounds the inner peripheral member, and extruding a resin from a lip formed between the inner peripheral member and the outer peripheral member, and a plurality of die lip drive mechanisms including a fluid pressure actuator as a drive source and adjusting a lip width by applying a radial load to the outer peripheral member, in which the outer peripheral member includes a plurality of load receiving portions to which a load is applied by the die lip drive mechanism, and a stiffness reducing portion that is provided between the plurality of load receiving portions.

An extrusion system, for example for extruding a food product, that includes: an extruder, which propels extrudate through an outlet of the extruder; and a valve. The valve includes: an inlet, which receives extrudate from the extruder outlet; a main conduit, which extends from the inlet to a main outlet; a dumping conduit, which extends from a junction with the main conduit to a dumping outlet; and a flow control member, which is operable to move between: a plurality of flow controlling positions, in which extrudate is directed to the main outlet, with the flow control member providing, for each flow controlling position, a respective amount of impedance to flow along the main conduit; and a flow diverting position, in which extrudate is directed along the dumping conduit to the dumping outlet.

The invention relates to a filter device for a plastic melt or another highly viscous fluid, comprising a housing with an inlet plate and a discharge plate. At least one spacing element and a screen wheel which can be rotated by a drive device are arranged between the inlet plate and the discharge plate. The inlet plate and the discharge plate are clamped against each other with the inclusion of the spacing element via at least three housing clamping elements. An engagement point of the drive device on the screen wheel is arranged outside of the pretensioning surface. When viewed in the rotational direction, an angle α larger than 110° and smaller than 160° is formed on the screen wheel between a first line that extends between the pretensioning surface centroid on which a resulting frictional force F.sub.R acts and the center of the screen wheel and a second line between the center and the engagement point on which an advancing force Fv acts.

Described is a system for transferring a dose of polymeric material comprising a head for supplying the polymeric material and at least one conveying device, provided with a conveying wall, which is configured for advancing along a path through the supplying head for transferring to the conveying wall a dose obtained from the polymeric material supplied from the supplying head; and wherein the supplying head comprises a duct which is provided with a straight outfeed region extending along an axis which is configured to supply the polymeric material to a supplying outfeed. The outfeed region comprises at least a first zone and a second zone facing each other, the supplying head having at least one variation configuration in which the first zone and the second zone are asymmetrical to disturb a flow of polymeric material in the outfeed region in such a way as to control the supplying direction of the polymeric material, supplied from the supplying outfeed and to transfer to the conveying wall. A method is also proposed for transferring the dose of polymeric material from the supplying head to the conveying device and a method for supplying the dose.

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.

An extruder has a valve assembly configured to move pins to open and close the nozzles in a multi-nozzle extruder head independently. The pins of the valve assembly that are driven by actuators into and out of engagement with nozzles in the extruder head are positioned within sleeves that extend between the valve assembly and the extruder head. A gap is provided between the extruder head and the end of the sleeves proximate the extruder head to enable thermoplastic material leaking from the extruder that contacts the pins to remain in a melted or plastic state so the thermoplastic material does not interfere with the movement of the pins.