The invention describes a method for the production and further processing of a film tube (6), in which method a plastic melt is transferred into a cylindrical melt by means of an extrusion die (4), the melt flow is drawn out through an annular gap (5) associated with the extrusion die (4) in order to form the film tube (6), and at least one temperature-controlled volume flow comprising at least one fluid is conducted by means of a temperature control device (8) onto the outer periphery of the film tube (6), wherein the temperature control device (8) is divided into peripheral segments, wherein a volume flow of different magnitude and/or different temperature is produced by means of each peripheral segment such that the temperature control of the film tube (6) differs over the periphery of the film tube, and wherein the film tube (6) is flattened by means of a flattening device (9), the flattening device (9) being rotated in relation to the extrusion die (4). A first volume flow in at least one peripheral segment of the temperature control device (8) differs from the volume flow of other peripheral segments so that at least one thick point (13) is produced on the film tube, wherein the first volume flow is produced by means of adjacent peripheral segments in succession, wherein the first volume flow is produced by means of the corresponding at least one peripheral segment in such a way that the first volume flow is adapted to the rotation of the flattening device (9) such that the at least one thick point (13) assumes substantially the same position in relation to the flattening device (9).

In the manufacture of double-walled corrugated extruded pipe it is desirable to form an integral connecting cuff that is of a single wall thickness and typically of a large diameter. The mold blocks and process parameters for forming of the cuff as part of an otherwise double-walled pipe requires a transition as the cuff moves past the die outlets. The present invention allows for accurate sensing and control of air pressure and temperature as the cuff moves past the die outlets. Improvements in both the die tooling and the method of manufacture are disclosed.

A squeezing roller granulator that has a squeezing roller pair composed of a toothed pressure roller and a toothed squeezing roller. The teeth of the pressure roller and the squeezing roller have tooth flanks that are situated between a tooth root region and a tooth tip region. The tooth root region has an outer diameter that is smaller than the outer diameter of the tooth tip region, and the tooth tip region of at least one of the rollers of the squeezing roller pair has three squeezing zones including a middle squeezing zone, which define different distances between the tooth tip regions with a minimum distance in the region of the middle squeezing zone, and the contour of the tooth flanks and the tooth root region of the rollers of the squeezing roller pair defines a maximum cross-section of granulate cushions to be formed.

The invention relates to a device for cooling a film (1) which can be produced in a film extrusion system in particular, comprising a housing (11) that has at least one channel (12), at least one inlet opening (13), and at least one outlet opening (14) through which a cooling gas (2) can flow and comprising an adjusting arrangement (10) with which the cooling gas (2) volumetric flow rate that can flow out of the outlet opening (14) and the temperature of the cooling gas (2) that can flow out of the outlet opening (14) can be adjusted. According to the invention, the adjusting arrangement (10) comprises a lever system which has a movable actuator (15) and a movable valve element (16), said actuator (15) acting on the valve element (16) such that an actuating effect of the valve element (16) is reinforced.

An improved control apparatus for producing plastic films and an associated improved method are distinguished, inter alia, by the following features: —the control apparatus has two stages or at least two stages, —the control apparatus comprises, for this purpose, a sensor module and/or a sensor model and a process module and/or a process model, —the machine-dependent sensor module and/or sensor model and the production-dependent process module and/or process model are linked or can be linked to one another via production variables, —adjustable machine variables are connected or linked to plant production variables via the sensor module and/or the sensor model.

A method of filling a mold comprising filling a majority of a mold cavity with an extrudate from at least one extruder wherein the extrudate, which is conveyed to an inlet of the mold, is at a pressure of 1-500 psi, subsequently isolating the mold cavity from a conduit which conveys the extrudate to the mold cavity, and subsequently using a pressurization member to fill a remainder of the mold cavity with additional extrudate, wherein the pressurization member excepts a pressure above 500 psi on the additional extrudate.

An air ring comprises a circular plenum in fluid communication with a source of pressurized air. An upper and lower annular lips are in fluid communication with the plenum through upper and lower channels and are arranged to supply air to the blown film bubble. A plurality of vanes are disposed in the upper channel and extend radially inwardly from the plenum to the upper annular lip. The vanes divide the upper channel into a plurality of radially extending channel segments. Each vane has a selected length and a distal end proximal the upper annular lip, the distal end being spaced from the upper annular lip no greater than about 20% of the length of the vanes. A powered plunger extends between the vanes of each of the channel segments to vary the cross-sectional area of the channel segments.

In the manufacture of double-walled corrugated extruded pipe it is desirable to form an integral connecting cuff that is of a single wall thickness and typically of a large diameter. The mold blocks and process parameters for forming of the cuff as part of an otherwise double-walled pipe requires a transition as the cuff moves past the die outlets. The present invention allows for accurate sensing and control of air pressure and temperature as the cuff moves past the die outlets. Improvements in both the die tooling and the method of manufacture are disclosed.

An apparatus includes an upper lip positioned with respect to an air flow passage. The upper lip is to direct air flow from the air flow passage around a bubble of blown film. The apparatus further includes a Venturi ring movably mounted with respect to the upper lip and adjustable in position with respect to the upper lip. The Venturi ring is to adjustably lock the bubble of blown film.

A blown-film extrusion apparatus for manufacturing a tubular polymer film comprises an extruder; a solidification ring for solidifying a tubular element produced by the extruder and for forming the film by delivering cooling air on the tubular element at a given cooling height, and a film conveyor for conveying the film upwards. The apparatus also comprises a delivery device for projecting correction air on the tubular element, in order to locally correct the thickness of the film, comprising a distribution chamber; a plurality of air delivery members with delivery channels whose delivery mouths are arranged about said axis of the apparatus for projecting correction air partial streams on respective angular correction positions, between the die and the cooling height; flow control elements between the distribution chamber, and the inlet of respective air delivery members, configured for adjusting the flowrate of the respective correction air stream according to an adjustment signal. According to an aspect of the invention, a plurality of separate radial ducts is provided defining respective delivery channels and spaced apart, at an own end portion, by separation spaces, so that the correction air partial streams, after hitting the tubular element in the respective angular correction positions, can flow away from the tubular element through said separation spaces. According to another aspect of the invention, the distribution chamber is defined by an upper ring and by a lower ring connected to each other by means of tight fixed joints with a first substantially cylindrical wall and with a second substantially cylindrical wall arranged around the first cylindrical wall, wherein possible separate radial ducts of the air delivery members protrude from the first cylindrical wall.