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.

The invention relates to a method for automatically regulating the size of a nozzle discharge slot of a nozzle assembly, wherein the nozzle assembly comprises a first and a second nozzle lip and a nozzle discharge slot arranged between the nozzle lips for setting in a controlled manner a thickness profile of a conveyable melt. A plurality of adjusting elements, in particular a plurality of adjusting pins, coupled to a respective thermoelement, is arranged on the first nozzle lip, the thermoelements being controllable by the regulation in such a way that the slot can be adjusted by the action of a mechanical force from the respective adjusting element on the first nozzle lip, as a result of the expansion or contraction of the thermoelements. At an initial operation of the nozzle assembly for conveying the melt, the adjusting elements for subsequent regulation of the slot size are set uniquely free from play as the initial setting. The invention further relates to a control and/or regulation system.

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 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.

Disclosed is an apparatus for the production of a blown tubular film (FT). The apparatus includes an independent device for the localized thickness adjustment at the strips adjacent to the folding edges resulting from the flattening of the tubular film (FT) by means of adjustment elements formed in angular sectors of limited extension symmetrically arranged 180° apart. The independent device for the localized thickness adjustment being a volumetric type device having a rotating ring that performs a rotating adjustment of the flow rate of a cooling air stream which takes into account the angular offset resulting from the operational parameters of the apparatus.

The invention relates to a method for measuring a tubular strand exiting from an extrusion device, wherein electromagnetic radiation is directed from at least one radiation source within a frequency range of 1 GHz to 6000 GHz from the inside to the inner side of the tubular strand, wherein electromagnetic radiation reflected by the tubular strand is received by at least one radiation receiver, and wherein the diameter, and/or the wall thickness, and/or deviations in shape of the tubular strand are ascertained from the received electromagnetic radiation. Moreover, the invention relates to a corresponding device.

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.

The method for setting an operating point of a film stretching system comprises the method steps: acquiring an input, wherein the input contains: a) a target value for the first production variable; or b) a target value for the second production variable; or c) a target value for the third production variable; specifying: a) a setting value for the second production variable and the third production variable in order to achieve the target value for the first production variable; or b) a setting value for the first production variable and the third production variable in order to achieve the target value for the second production variable); or c) a setting value for the first production variable and the second production variable in order to achieve the target value for the third production variable; controlling the motor arrangement and the extruder arrangement by the control device in such a way that the operating point consisting of the target value and two setting values is reached.

A system for controlling parameters of polymeric film includes an extruder and a die which has a gap. A plurality of regulators are positioned along the die for regulating the gap. A cooling cylinder is located downstream of the die and a polymeric melt extends from the die to the cooling cylinder. A haze generator for creating a haze lane in the polymeric melt is located proximate the gap. A haze sensor system is located downstream from the gap in a measuring location. The haze sensor system is locates a transverse point for the respective haze lane in the polymeric film at the measuring location. The haze sensor system is in communication with the regulators to adjust the gap based on a correlation of haze lane position at origin point and transverse point at the measuring location.

A multilayer film having coextruded layers comprising a znLLDPE-based core layer, and mLLDPE-based outer layers on each side of the core layer comprising, wherein the znLLDPE of the core layer has a density which is less than 0.005 g/cc different from a density of the mLLDPE of the outer layers, and wherein the znLLDPE of the core layer has a melting temperature which is less than 15 C. different from a melting temperature of the mLLDPE of the outer layers.