The invention relates to a method for subsequently controlling the temperature of a film tube extruded by means of a film blowing installation, the method having the following method steps: - ejecting a film tube (1) of plasticised thermoplastic material in a drawing direction along a longitudinal axis (L) of the film blowing installation by means of a film blowing die (6), - flowing cooling gas onto the film tube (1) in the drawing direction downstream of the film blowing die (6) by means of at least one cooling gas ring (10) such that the film tube (1) hardens under the effect of the cooling gas at a frost line (14), - subsequently controlling the temperature of the film tube (1) by means of a subsequent temperature control unit (20) downstream of the frost line (14), wherein the subsequent temperature control unit (20) has a plurality of adjustable blowing elements (22) for blowing temperature control gas onto the film tube (1), the blowing elements forming a through-opening for the film tube (1), - adapting a diameter (D) of the through-opening formed by the blowing elements (22) to a diameter of the film tube (1) by adjusting the blowing elements (22), - measuring the actual temperature of the film tube (1) downstream of at least one of the blowing elements (22), and - regulating the temperature of the film tube (1) downstream of the at least one blowing element (22) to a target temperature by blowing temperature control gas onto the film tube (1) by means of the subsequent temperature control unit (20).
B29C 48/10 - Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels flexible, e.g. blown foils
B29C 48/90 - Thermal treatment of the stream of extruded material, e.g. cooling with calibration or sizing, i.e. combined with fixing or setting of the final dimensions of the extruded article
The invention relates to a method for determining the position of a frost limit (11) of a tubular film (2) made of thermoplastic material during the production thereof, comprising the following method steps: detecting a temperature curve (33) of the tubular film (2) along a first measurement section (M1) along the production axis (P);ascertaining a position along the first measurement section (M1), in which position an absolute value of a temperature gradient of the temperature curve (33) in the production direction (R) does not meet a predetermined limit value, and fixing the position as the first preliminary position (h1) of the frost limit (11);detecting a diameter curve (34) of the tubular film (2) along a second measurement section (M2) along the production axis (P);ascertaining a position along the second measurement section (M2), in which position an absolute value of a diameter gradient of the diameter curve (34) in the production direction (R) does not meet a predetermined limit value, and fixing the position as the second preliminary position (h2) of the frost limit (11); and checking a plausibility of the first preliminary position (h1) and the second preliminary position (h2) of the frost limit (11) on the basis of the mutual spacing (Δh) thereof.
A device for guiding a film tube emerging from a film blowing head and drawn off in a production direction, including a frame (48) through which the film tube (16) can be passed in the production direction (P), and a plurality of adjusting units (59, 60) distributed over the circumference for adjusting film guide elements (47) transversely to the production direction (P), the adjusting units (59, 60) each having: a pivot arm (50), pivotally attached to the frame (48), a carrier (51) for at least one of the film guide elements (47), the carrier (51) being pivotally connected to the pivot arm (50), and a coupling rod (52) pivotably connected to the carrier (51). At least one first adjusting unit (59) has an actuating mechanism (53, 54) through which the coupling rod (52) the adjusting unit (59) is connected in an articulating manner to the frame (48).
Device for guiding a film tube, comprising a frame, and a plurality of adjusting units for adjusting film guide elements transversely to a production direction, having the follow- ing: a pivot arm pivotally attached to the frame, a carrier for at least one of the film guide elements, the carrier being pivotally connected to the pivot arm, and a coupling rod pivotably connected to the carrier. The at least one first adjusting unit has an actuating mechanism by means of which the coupling rod of the at least one first ad- justing unit is connected in an articulating manner to the frame. The at least one first adjusting unit 49, 59 forms a coupler gear or a cam gear.
B29C 48/00 - Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired formApparatus therefor
B29C 48/10 - Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels flexible, e.g. blown foils
B29C 48/90 - Thermal treatment of the stream of extruded material, e.g. cooling with calibration or sizing, i.e. combined with fixing or setting of the final dimensions of the extruded article
B29C 55/28 - Shaping by stretching, e.g. drawing through a dieApparatus therefor of blown tubular films, e.g. by inflation
An apparatus for guiding a film tube which leaves a blown-film die and is drawn off in a production direction, having a frame (48), through which the film tube (16) can be guided in the production direction (P), and having a plurality of circumferentially distributed adjustment units (59, 60) for adjusting film-guiding elements (47) in a direction transverse to the production direction (P), wherein the adjustment units (59, 60) each have the following: a pivoting arm (50), which is fastened in a pivotable manner on the frame (48), a carrier (51) for at least one of the film-guiding elements (47), wherein the carrier (51) is connected in a pivotable manner to the pivoting arm (50), and a coupling rod (52), which is connected in a pivotable manner to the carrier (51), characterized in that at least one first adjustment unit (59) of the plurality of adjustment units has a control mechanism (53, 54), by means of which the coupling rod (52) of the at least one first adjustment unit (59) is connected in an articulated manner to the frame (48).
B29C 48/00 - Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired formApparatus therefor
B29C 48/10 - Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels flexible, e.g. blown foils
B29C 48/90 - Thermal treatment of the stream of extruded material, e.g. cooling with calibration or sizing, i.e. combined with fixing or setting of the final dimensions of the extruded article
B29C 55/28 - Shaping by stretching, e.g. drawing through a dieApparatus therefor of blown tubular films, e.g. by inflation
6.
Cooling device with a cooling gas ring and a flow guiding device
A cooling device for external cooling of a film tube subjected to internal pressure in the production of blown films of thermoplastic material includes a cooling gas ring with a ring housing and a ring nozzle arranged concentrically to a central axis and being open towards the film tube. At least one inner ring channel extending in the circumferential direction about the central axis and being open radially inwards towards the ring nozzle is included. At least one feed channel for supplying cooling gas is attached to the ring housing and connected to the ring channel. The cooling device also includes at least one flow guiding device arranged in the at least one feed channel. When a cooling gas flows through the flow guiding device, at least a partial flow of the cooling gas is set in rotation about a flow axis prior to flowing into the ring channel.
A cooling device for the external cooling of a film tube subjected to internal pressure in the production of blown films of thermoplastic material is disclosed. The cooling device comprises a cooling gas ring comprising a ring housing with a ring nozzle arranged concentrically to a central axis and being open towards the film tube, and a ring channel extending in the circumferential direction about the central axis and being open radially inwards towards the ring nozzle. A feed channel for supplying cooling gas is attached to the ring housing and connected to the ring channel. The cooling device further comprises a flow guiding device which is arranged in the feed channel. When a cooling gas flows through the flow guiding device, at least a partial flow of the cooling gas is set in rotation about a flow axis prior to flowing into the ring channel.
A calibration device for calibrating an extruded film tube, above the frost line, forms an annular gap between the calibration device and the film tube. The calibration device includes a plurality of calibration segments and at least one blowing nozzle. The plurality of calibration segments are distributed around a longitudinal axis and form a central feed through opening for feeding through the film tube along the longitudinal axis. The calibration segments are adjustable for adjusting the diameter of the feed through opening. The at least one blowing nozzle for each calibration segment, feeds a calibration gas to the feed through opening. The at least one blowing nozzle is formed such, that the calibration gas is guided to the annular gap substantially parallel to a surface of the film tube and that the calibration gas flows through the annular gap in a single flow direction.
B29C 47/00 - Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor (extrusion blow-moulding B29C 49/04)
Calibration device 15 for calibrating an extruded film tube 8 above the frost line 14, wherein an annular gap 36 is formed between the calibration device 15 and the film tube 8, comprising a plurality of calibration segments 16 distributed around a longitudinal axis L and forming a central feed through opening 26 for feeding through the film tube 8 along the longitudinal axis L, wherein the calibration segments 16 are adjustable for adjusting the diameter of the feed through opening 26, and at least one blowing nozzle 28 for each calibration segment 16, said at least one blowing nozzle 28 feeds a calibration gas to the feed through opening, that said at least one blowing nozzle 28 is formed such, that the calibration gas is guided to the annular gap 36 substantially parallel to a surface of the film tube and that the calibration gas flows through the annular gap 36 in a single flow direction.
B29C 48/90 - Thermal treatment of the stream of extruded material, e.g. cooling with calibration or sizing, i.e. combined with fixing or setting of the final dimensions of the extruded article
09 - Scientific and electric apparatus and instruments
11 - Environmental control apparatus
Goods & Services
Machines for plastics processing and shaping of plastics and parts therefor; Cooling air rings for plastics manufacturing and processing installations. Electric and electronic control and regulating apparatus for plastics manufacturing and processing installations. Regulating systems for cooling air rings and regulating accessories for cooling ventilation systems.
11.
Method of and device for cooling blown film during the production of blown film
B29C 47/00 - Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor (extrusion blow-moulding B29C 49/04)
A method of cooling blown film 14 consisting, of thermoplastic plastics during the production of blown film by means of a blown film extruder 10 with a film blowing head 11 which comprises an annular nozzle 12 from which the blown film 14 emerges and is guided away in an extraction direction, wherein at least two cooling gas flows are made to approach the blown film 14 from the outside in at least two blowing-out planes located at a distance from the annular nozzle, wherein at least one cooling gas flow K G is blown out in the direction opposed to the extraction direction of the blown film (14) and wherein at least one cooling gas flow K A is blown out in the extraction direction of the blown film 14, and wherein, at least one of the cooling gas flows K G, K A can be controlled around their circumference in sectors, at least in respect of its volume flow or temperature.
