Abstract: A film blowing head for the production of film tubing from a single or multi-layer film includes an extrusion gap to form a film layer. The extrusion gap is embodied between two boundary walls, with at least one melt pipeline mouthing into the extrusion gap, which converts inside the extrusion gap into a first melt channel, which is formed in a section of the progression of the first melt channel by recesses in the two boundary walls of the extrusion gap, and which distributes melt in the extrusion dap. The first melt channel tapers in the progression in the direction of transportation of the melt (h), and in an end section, entirely converts into the extrusion gap. The first melt channel is formed at one of the sections only by the recesses in one of the two boundary walls.

Abstract: A blow head for production of a multilayer blown film with at least two plastic layers has melt guide areas, which are traversed in succession in the direction of flow (z) of the melt, including feed lines to at least two individual gaps for guiding an individual stream, and an annular gap for combining of the film composite. At least one thermocouple is arranged on at least one flow path of at least one individual stream before the stream reaches the annular gap.

Abstract: A film blowing head (1) for the production of film tubing from a single or multi-layer film, which (1) comprises at least one extrusion gap (4) to form a film layer, which (4) is embodied between to boundary walls (5, 6), with at least one melt pipeline (22) mouthing into the extrusion gap (4), which converts inside the extrusion gap (4) into a first melt channel (4), which is formed in at least one section (11, 12, 13, 14) of the progression of at least one first melt channel (10) by recesses (3, 7) in the two boundary walls (5, 6) of the extrusion gap (4), and which distributes the melt in the extrusion gap (4), while it (10) tapers in its progression in the direction of transportation of the melt (h), and finally in its (10) end section (14) entirely converts into the extrusion gap (4). Here, it is considered novel and inventive that at least one first melt channel (10) is formed at one of its sections (11, 12, 13, 14) only by recesses (3, 7) in one of its two boundary walls (5, 6).

Abstract: The invention describes a blow head (1, 21, 208) for production of a multilayer blown film (18) with at least two plastic layers, which (1, 21, 208) has at least the following melt guiding areas (16, 17, 25, 205), which are traversed in succession in the direction of flow (z) of the melt: feed lines (25, 205) to the at least two individual gaps for guiding an individual stream at least two individual gaps (16) for guiding of an individual stream an annular gap (17) for combining of the film composite (18). At least one thermocouple (85, 142) is arranged on at least one flow path of at least one individual stream before it reaches the annular gap (17).

Abstract: Tubular film die head for extruding single-layer or multi-layer film which has at least the following features: a substantially annular die gap, fastening elements which fix at least two components with respect to one another which together border areas bearing plastic melt within the tubular film die head, coolant-carrying elements. At least one part of the fastening elements is structured as coolant-carrying elements.

Abstract: A process is described for manufacturing blown film tubes (3) that are equipped with at least one self-cleaning surface that contains the following characteristics of the process: Formation of a plastic melt in an extruder (2) Compression of the plastic melt in a blowing head that has a ring-shaped output gap. Extrusion of a film tube (3) from this ring-shaped gap Expansion of the radius (R1) of the film tube (3) by creating a corresponding pressure inside the film tube (3) by the blow factor (FR) Squeezing the film tube (3) with nip rollers (4) Stretching the film tube (3) in its axial direction (z) by the length stretch factor (FZ). The inventiveness lies in the fact that at least one surface of the film tube (3) is provided with elevations in that the material required for the formation of the elevations is either added before the extrusion of the plastic melt from the ring-shaped gap or is spread on at least one surface of the film tube (3) after the extrusion.

Abstract: Tubular film die head (1) for extruding single-layer or multi-layer film which has at least the following features: a substantially annular die gap (11), fastening means which fix at least two components (5, 7, 8, 9) with respect to one another which together border areas (14) bearing plastic melt within the tubular film die head, coolant-carrying elements, where at least one part of the fastening elements (15) is structured as coolant-carrying elements (24).

Abstract: An extruder die head for producing multilayered tubes made of thermoplastic material exhibits a central annular channel, which is provided with an annular outlet die. Into the outer limiting wall of the channel empty annular slits, which feed a polymer melt and which constitute the smaller diameter openings of truncated channels, formed between the internal and external shells of stacked, conical insert members. To reduce the axial length of the extruder die head, the annular slits, feeding the polymer melts, also empty into the inside wall of the central annular channel. The annular slits are the smaller diameter openings of truncated channels, formed between the internal and external shells of stacked conical internal insert members.

Abstract: An extruder die head for producing multilayered tubes made of thermoplastic material exhibits a central annular channel, which is provided with an annular outlet die. Into the outer limiting wall of the channel empty annular slits, which feed a polymer melt and which constitute the smaller diameter openings of truncated channels, formed between the internal and external shells of stacked, conical insert members. To reduce the axial length of the extruder die head, the annular slits, feeding the polymer melts, also empty into the inside wall of the central annular channel. Said annular slits are the smaller diameter openings of truncated channels, formed between the internal and external shells of stacked conical internal insert members.

Abstract: To control the film thickness in a blown film extrusion line with reversing or rotating takeoff of the film bubble, the thickness profile of the blown film bubble is measured over its circumference. Different temperatures can be applied to sections of the film bubble by a die ring divided into heating sections provided with control elements or by heating elements, forming a ring around the extruded film bubble and provided with control elements. In order to correctly assign the position of the measured thickness profile to the heating sections of the die ring or the heating elements, the extruded film bubble is provided with a mark in the region of the die ring or the heating elements and the rotation of this mark is measured by a measuring device at specified intervals from the die ring or the heating elements.

Abstract: A device to lay flat a film tube drawn from an inflated film bubble generated in a film blowing system includes lay-flat platens which delimit the film bubble and which are placed against the bubble in the form of a wedge. The platens are positioned in front of the squeeze rollers of a film take-up and winding device and have slip elements arranged transversely relative to the take-up device. A driven reversing frame can be provided to hold the lay-flat platens, support the squeeze rollers, and support guide rollers and turning bars about its rotating axis in a pivoting fashion. In order to decrease the friction between the film tube which is to be laid flat and the lay-flat platens, particularly for a reversing take-up, the slip elements have hollow sections including air blast nozzles or air blast slots facing the film tube to be laid flat. The hollow sections can be connected by lines to an air blast source.

Abstract: A withdrawal device for a plastic tubular film is manufactured in a blowing method by an extruder. To prevent the formation of center wrinkles in the withdrawal of plastic tubular film, at least one deflection cylinder and/or angle bar has a differing diameter across its length.

Abstract: A film blowing head for extruding a tubular web of a thermoplastic synthetic melt consists of at least one inner cooling ring and a pipe passing through the blowing head, wherein a central pipe is arranged with the formation of an annular space. The annular space is placed in an air conducting communication with the inner cooling ring. The cooling and supporting air is fed via lines into the annular space and is drawn off again through the central pipe. To permit cooling with very cold air, the pipe feeding the cooling air is surrounded, in the zone of the blowing head, by two concentric pipes with the formation of two annular spaces. The two annular spaces are connected with each other in the zone of the plane of the outlet nozzle gap of the blowing head by an overflow compartment that is closed towards the outside. Warm air is fed to one of the annular spaces, and is drawn off again through the other annular space.

Abstract: To determine and/or automatically control the degree of orientation of tubular films which have been made in a film-blowing plant including an extruder having a film-blowing head and apparatus for internal cooling and also including flattening and take-off apparatus, the rate of exchange of the air for internal cooling, the speed of the extruder, the temperature of the plastic composition being extruded and/or the take-off velocity are controlled. To ensure that the degree of orientation can be determined and/or automatically controlled in a simple manner and without an occurrence of trouble, that shape of the flaring portion of the bubble which corresponds to the desired degree of orientation is determined and/or adjusted and is recorded as the desired shape of the bubble. The actual shape of the flaring portion of the bubble is detected and compared with and adapted to the desired shape.

Abstract: For measuring thickness of films of synthetic thermoplastic which have been solidified but not yet fully cooled after extrusion, a capacitive measuring head is moved into contact with the film and during a measuring cycle is moved over the surface of the film in the area in which the measurement is to be effected. The measuring head is disengaged from the film after each measuring cycle. To ensure that the measurement will not be affected by a temperature rise of the measuring head during a measuring cycle, the measuring head is moved into contact with the film before the measuring cycle begins and the measuring cycle is not initiated until a time has elapsed in which the measuring head has assumed a temperature which remains substantially constant throughout the measuring cycle.