DE2313950A1 - SCREW EXTRUSION PRESS FOR PLASTIC PIPES - Google Patents
SCREW EXTRUSION PRESS FOR PLASTIC PIPESInfo
- Publication number
- DE2313950A1 DE2313950A1 DE2313950A DE2313950A DE2313950A1 DE 2313950 A1 DE2313950 A1 DE 2313950A1 DE 2313950 A DE2313950 A DE 2313950A DE 2313950 A DE2313950 A DE 2313950A DE 2313950 A1 DE2313950 A1 DE 2313950A1
- Authority
- DE
- Germany
- Prior art keywords
- wall thickness
- scanning device
- plastic pipe
- screw extruder
- pipe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/92—Measuring, controlling or regulating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2948/00—Indexing scheme relating to extrusion moulding
- B29C2948/92—Measuring, controlling or regulating
- B29C2948/92009—Measured parameter
- B29C2948/92114—Dimensions
- B29C2948/92152—Thickness
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2948/00—Indexing scheme relating to extrusion moulding
- B29C2948/92—Measuring, controlling or regulating
- B29C2948/92323—Location or phase of measurement
- B29C2948/92428—Calibration, after-treatment, or cooling zone
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2948/00—Indexing scheme relating to extrusion moulding
- B29C2948/92—Measuring, controlling or regulating
- B29C2948/92504—Controlled parameter
- B29C2948/9258—Velocity
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2948/00—Indexing scheme relating to extrusion moulding
- B29C2948/92—Measuring, controlling or regulating
- B29C2948/92504—Controlled parameter
- B29C2948/92609—Dimensions
- B29C2948/92647—Thickness
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2948/00—Indexing scheme relating to extrusion moulding
- B29C2948/92—Measuring, controlling or regulating
- B29C2948/92819—Location or phase of control
- B29C2948/92857—Extrusion unit
- B29C2948/92904—Die; Nozzle zone
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C2948/00—Indexing scheme relating to extrusion moulding
- B29C2948/92—Measuring, controlling or regulating
- B29C2948/92819—Location or phase of control
- B29C2948/92933—Conveying, transporting or storage of articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/09—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
- B29C48/10—Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels flexible, e.g. blown foils
Description
Diplom-Physiker Dr. Waiter Andrejewski Diplom-Ingenieur Dr.-lng. Manfred Honke Diplom-Ingenieur Anwaltsakte: 4o 423/Fm-th Hans Dieter GesthuysenPhysicist Dr. Waiter Andrejewski graduate engineer Dr.-lng. Manfred Honke Graduate Engineer Lawyer files: 4o 423 / Fm-th Hans Dieter Gesthuysen
4300 Essen, den 20.März 1973 Thaaterplatz 3 4300 Essen, March 20, 1973 Thaaterplatz 3
■■<·■·■■ <· ■ ·
Patent- undPatent and
Gebrauchsmusterhilfsanmeldung
HERJORTH PLASTICS LIMITED
Genefax House,
Tapton Park Road,Utility model registration
HERJORTH PLASTICS LIMITED
Genefax House,
Tapton Park Road,
SheffieldSheffield
EnglandEngland
Schneckenstrangpresse für Kunststoffrohre.Screw extruder for plastic pipes.
Die Erfindung betrifft eine Schneckenstrangpresse für Kunststoffrohre mit einem der Preßmatrize nachgeschalteten Kalibriermantel und einem Abzugswerk für das Fertigteil.The invention relates to a screw extruder for plastic pipes with a calibration jacket downstream of the press die and a take-off mechanism for the finished part.
Bereits seit langen Jahren werden Kunststoffrohre auf Schneckenstrangpressen hergestellt, in denen das polymere Material auf die gewünschte Temperatur erhitzt und durch eine Preßmatrize hindurchgedrückt wird, sodaß ein Rohr entsteht, welches an-Plastic pipes have been screw extrusions for many years produced in which the polymeric material is heated to the desired temperature and passed through a press die is pushed through, so that a tube is created, which
409823/0990409823/0990
ORIGINAL INSPECTEDORIGINAL INSPECTED
— 2 —- 2 -
schließend entweder durch Innendruck oder durch von außen her wirkenden Saugdruck gegen die Innenwandung eines Kalibriermantels oder Kalibriergehäuses gepreßt wird. Dieser Kalibriermantel besitzt Kühlorgane, u;r. das in weichem Zustande aus der Preßrnatrize herauskommende Kunststoffrohr in der gewünschten Abmessung zu fixieren, während gleichzeitig das Rohr durch ein Abzugswerk abgezogen wird.closing either by internal pressure or by suction pressure acting from outside against the inner wall of a calibration jacket or calibration housing is pressed. This calibration jacket has cooling elements, u; r. that in a soft state from the Press die to fix the plastic pipe coming out in the desired dimension, while at the same time pushing the pipe through Trigger mechanism is withdrawn.
Wenn auch bei einer derartigen Schneckenstrangpresse die Preßmatrize auf einen unbedingt gleichmäßigen kreisringförmigen Austrittsschlitz eingestellt werden kann, so ergibt sich bedauerlicherweise daraus doch noch nicht, daß die Wandstärke des stranggepreßten Rohres in erkaltetem Zustande völlig gleichmäßig ist. Um diese Veränderungen in der Wandstärke zu korrigieren, ist es üblich, den Dorn oder den Außenring der Preßrnatrize durch rund um den Matrizenring-verteilte Stellschrauben derart zu verschieben, daß der Fluß der Schmelze an der Stelle der größten Wandstärke eingeengt wird und/oder entsprechend der Temperatur und/oder der Veränderung der Viskosität der Schmelze eine Erhöhung der Lineargeschwindigkeit der Schmelze erzielt wird. Zur Korrektur wird gleichzeitig die Geschwindigkeit des Abzugswerkes für das Fertigteil eingestellt. Hierbai ist es jedoch erforderlich, abzuwarten, bis eine entsprechende Rohrlänge hergestellt wurde, welche nach dem Abkühlen abgetrennt und bezüglich ihrer Wandstärke genau nachgemessen werden kann, bevor derartige Einstellungen vorgenommen werden können. In dieser Zeit wird jedoch durch die Schneckenstrangpresse eine beträchtliche Rohrlänge hergestellt, bevor ein Rohr entsteht, dessen Wandstärke völlig gleichmäßig ist und den Anforderungen gena .: en ^spricht. WennEven if the extrusion die in such a screw extruder can be set to an absolutely uniform circular exit slot, so it regrettably results This does not mean that the wall thickness of the extruded pipe is completely uniform in the cold state is. To correct for these changes in wall thickness, it is common to pass the mandrel or the outer ring of the press die through set screws distributed around the die ring move so that the flow of the melt is restricted at the point of greatest wall thickness and / or according to the temperature and / or the change in the viscosity of the melt results in an increase in the linear velocity of the melt. To the Correction, the speed of the take-off mechanism for the finished part is set at the same time. Here, however, it is necessary wait until a corresponding pipe length has been produced, which is separated after cooling and with regard to its Wall thickness can be measured accurately before such settings can be made. During this time, however, will a considerable length of pipe is produced by the screw extruder before a pipe is produced, the wall thickness of which is completely is uniform and complies with the requirements.: en ^ speaks. if
409823/0990409823/0990
sich bei diesen Messungen herausstellt, daß das Rohr an irgendeiner Stelle eine geringere Wandstärke aufweist, als dies den Normen entspricht, so muß das Rohr verschrottet werden, während andererseits, wenn eine Wandstärke gemessen wird, welche im Ganzen dicker ist, als dies in den Normen vorgesehen ist, unnötig hohe Materialkosten entstehen, welche der Hersteller selbst tragen muß, wobei sich außerdem bei der Verbindung derartiger Rohre mit anderen den Normen entsprechenden Rohren Schwierigkeiten ergeben können.it turns out during these measurements that the pipe is at some Place has a smaller wall thickness than this corresponds to the standards, the pipe must be scrapped while on the other hand, if a wall thickness is measured which is thicker as a whole than is provided in the standards, this is unnecessary high material costs arise, which the manufacturer must bear himself, and in addition, when connecting such Pipes with other pipes conforming to the standards can cause difficulties.
Die Erfindung hat sich daher die Aufgabe gestellt, eine Schneckenstrangpresse der eingangs genannten Art in der Weise auszubilden, daß die Wandstärke eines stranggepreßten Kunststoffrohres vor seinem endgültigen Erhärten gemessen werden kann, und die Preßmatrize und/oder das Abzugswerk entsprechend eingestellt werden kann.The invention has therefore set itself the task of developing a screw extruder of the type mentioned at the beginning train that the wall thickness of an extruded plastic pipe can be measured before its final hardening, and the press die and / or the trigger mechanism accordingly can be adjusted.
Eine erfindungsgemäße Schneckenstrangpresse ist im wesentlichen dadurch gekennzeichnet, daß der Kalibriermantel aus.hintereinander liegenden Abschnitten besteht, deren einer sich an die Preßmatrize anschließt, während der andere in Abzugsrichtung des Kunststoffrohres mit einem Zwischenraum dem ersten Abschnitt nachgeschaltet ist und in diesem Zwischenraum eine die Wandstärke des Kunststoffrohres feststellende Abtasteinrichtung auf einem Schlitten um das Kunststoffrohr verdrehbar angeordnet ist.A screw extruder according to the invention is essentially characterized in that the calibrating jacket consists of one behind the other lying sections, one of which is connected to the press die, while the other in the withdrawal direction of the plastic pipe is connected downstream of the first section with a gap and the wall thickness in this gap The scanning device detecting the plastic pipe is arranged on a slide so that it can rotate around the plastic pipe is.
409823/0990409823/0990
Die Abtasteinrichtung, welche nach dem Prinzip der radioaktiven Reflexionsmessung (back scatter-type) arbeiten kann, kann eine optische Anzeigeeinrichtung für die Wandstärke des gesamten Rohrumfanges aufweisen, sodaß sofort festzustellen ist, an welcher Stelle eine Einstellung der Preßmatrize erforderlich ist. Der Maschinenwärter kann dann sofort die Preßmatrize entsprechend einstellen, um eine völlig gleichmäßige Wandstärke für den gesamten Rohrumfang zu erhalten. Außerdem kann ein Geschwindigkeitsversteller für das Abzugswerk vorgesehen sein, sodaß der Maschinenwärter hierdurch die allgemeine Wandstärke des Rohres entsprechend den bestehenden Normen verändern kann.The scanning device, which can work on the principle of radioactive reflection measurement (back scatter-type), can be a Have optical display device for the wall thickness of the entire pipe circumference, so that it can be determined immediately which point an adjustment of the press die is required. The machine operator can then immediately press the die set accordingly in order to obtain a completely uniform wall thickness for the entire circumference of the pipe. In addition, a Speed adjuster for the take-off mechanism can be provided so that the machine operator can thereby determine the general wall thickness of the pipe can change according to the existing standards.
Eine genauere Erläuterung der Erfindung ergibt sich aus der nachfolgenden Beschreibung eines bevorzugten Äusführungsbeispiels anhand der beiliegenden Zeichnung, welche eine erfindungsgemäße Schneckenstrangpresse in schematischer Darstellung in Seitenansicht zeigt.A more detailed explanation of the invention results from the following description of a preferred embodiment with reference to the accompanying drawing, which shows a screw extruder according to the invention in a schematic representation shows in side view.
Die in der Figur dargestellte Schneckenstrangpresse 1 besitzt eine Preßmatrize 2 mit Einstellschrauben J5 zur Herstellung eines Kunststoffrohres 4, welches durch einen Kalibriermantel hindurchläuft, der in zwei Abschnitte 5A und 5B unterteilt ist, zwischen denen ein Zwischenraum freibleibt. In diesem Zwischenraum läuft auf einem durch das Rechteck 7 angedeuteten Schlitten eine Abtasteinrichtung 6 um das Rohr herum, welche nach dem Prinzip der radioaktiven Reflexionsmessung (back scatter-type) arbeitet. Diese Abtasteinrichtung 6 mißt die Wandstärke des den Abschnitt 5A des Kalibriermantels verlassenden Kunststoffrohres, während die allgemeine Wandstärke durch die Geschwindigkeit desThe screw extruder 1 shown in the figure has a press die 2 with adjusting screws J5 for production a plastic pipe 4, which through a calibration jacket passes through, which is divided into two sections 5A and 5B, between which a space remains. In this intermediate space, a carriage indicated by the rectangle 7 runs a scanning device 6 around the tube, which is based on the principle of radioactive reflection measurement (back scatter-type) is working. This scanning device 6 measures the wall thickness of the plastic pipe leaving section 5A of the calibration jacket, while the general wall thickness is determined by the speed of the
409823/0990409823/0990
Abzugswerkes 8 gesteuert wird, welches das erkaltete Kunststoffrohr vom zweiten Abschnitt 5B der Kalibriereinrichtung abzieht. Die Abtasteinrichtung 6 wird mittels eines Motors 9 um das Kunststoffrohr herumgedreht, während das Abzugswerk 8 über einen Motor 10 angetrieben wird, welcher durch einen Geschwindigkeitsversteller 11 über eine Steuereinrichtung 12 gesteuert wird, welche auch den Motor 9 mit Strom versorgt. Die Steuereinrichtung 12 empfängt Signale von der Abtasteinrichtung 6 und zeigt in einer Anzeigevorrichtung IJ> fortlaufend die V/andstärke an, sodaß der Maschinenwärter die Preßmatrize 2 mit Hilfe der Stellschrauben 3 einstellen kann, um eine praktisch gleichmäßige V/andstärke über den gesamten Rohrumfang zu erreichen, während er gleichzeitig die Geschwindigkeit des Abzugswerkes 8 einstellen kann, um die gewünschte allgemeine V/andstärke über die gesamte Rohrlänge zu erreichen.Trigger mechanism 8 is controlled, which removes the cooled plastic pipe from the second section 5B of the calibration device. The scanning device 6 is rotated around the plastic pipe by means of a motor 9, while the take-off mechanism 8 is driven by a motor 10 which is controlled by a speed adjuster 11 via a control device 12 which also supplies the motor 9 with power. The control device 12 receives signals from the scanning device 6 and continuously shows the V / and thickness in a display device IJ> so that the machine operator can adjust the press die 2 with the help of the adjusting screws 3 to achieve a practically uniform V / and thickness over the entire pipe circumference , while at the same time he can adjust the speed of the take-off mechanism 8 in order to achieve the desired general V / and strength over the entire length of the pipe.
Es dürfte einleuchten, daß die Einstellungen bei der erfindungsgemäßen Maschine wesentlich schneller erfolgen können, als bei den bisher üblichen Maschinen, bei denen die Wandstärke erst an einer abgetrennten, völlig erhärteten Rohrlänge Hx gemessen wird, sodaß infolgedessen die Ausschußrate wesentlich verringert und eine beträchtliche Materialeinsparung erzielt werden kann.It should be clear that the settings can be made much faster with the machine according to the invention than with the previously common machines, in which the wall thickness is only measured on a severed, fully hardened pipe length Hx , so that as a result the reject rate is significantly reduced and considerable material savings achieved can be.
Ansprüche:Expectations:
409823/0990409823/0990
Claims (4)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB5342772 | 1972-11-18 |
Publications (1)
Publication Number | Publication Date |
---|---|
DE2313950A1 true DE2313950A1 (en) | 1974-06-06 |
Family
ID=10467771
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE2313950A Pending DE2313950A1 (en) | 1972-11-18 | 1973-03-21 | SCREW EXTRUSION PRESS FOR PLASTIC PIPES |
Country Status (7)
Country | Link |
---|---|
JP (1) | JPS4981464A (en) |
AU (1) | AU5003272A (en) |
DE (1) | DE2313950A1 (en) |
FR (1) | FR2207016A1 (en) |
IT (1) | IT973002B (en) |
NL (1) | NL7301660A (en) |
ZA (1) | ZA728754B (en) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS55216B2 (en) * | 1975-03-13 | 1980-01-07 | ||
JPS5242556A (en) * | 1975-09-30 | 1977-04-02 | Kubota Ltd | Method of automatically controlling tube thickness in extrusion molding of tube |
DE3906363C1 (en) * | 1989-03-01 | 1990-11-08 | Inoex Gmbh Innovationen Und Ausruestungen Fuer Die Extrusionstechnik, 4970 Bad Oeynhausen, De | |
ATE99596T1 (en) * | 1989-10-31 | 1994-01-15 | Inoex Gmbh | EXTRUDING PLANT FOR PLASTIC PIPES. |
DE102006045101A1 (en) * | 2006-09-21 | 2008-04-03 | Sobotta, Andreas, Dipl.-Ing. | A method for determining a location coordinate of a point on a strand issuing from an extrusion die, and a quality feature of an extrusion die, an extrusion device or a material for producing a profile |
CN109016461A (en) * | 2018-05-29 | 2018-12-18 | 湖南联塑科技实业有限公司 | A kind of novel PPR pipe outer diameter variation online automatic detection monitoring and alarming system |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1251014B (en) * | 1967-09-28 | |||
DE971619C (en) * | 1953-05-05 | 1959-02-26 | Troester Maschf Paul | Device for checking the walls in the manufacture of hoses and pipes using radioactive emitters |
DE1157682B (en) * | 1953-12-04 | 1963-11-21 | Elektro Schmitz O H G | Control device for cable extrusion machines |
GB1370946A (en) * | 1971-05-14 | 1974-10-16 | Wavin Plastics Ltd | Extrusion of thermoplastics materials |
-
1972
- 1972-12-12 ZA ZA728754A patent/ZA728754B/en unknown
- 1972-12-13 AU AU50032/72A patent/AU5003272A/en not_active Expired
- 1972-12-28 IT IT33680/72A patent/IT973002B/en active
-
1973
- 1973-01-29 FR FR7303874A patent/FR2207016A1/en active Granted
- 1973-02-06 NL NL7301660A patent/NL7301660A/xx unknown
- 1973-02-21 JP JP48020311A patent/JPS4981464A/ja active Pending
- 1973-03-21 DE DE2313950A patent/DE2313950A1/en active Pending
Also Published As
Publication number | Publication date |
---|---|
JPS4981464A (en) | 1974-08-06 |
AU5003272A (en) | 1974-06-13 |
ZA728754B (en) | 1973-08-29 |
NL7301660A (en) | 1974-05-21 |
FR2207016A1 (en) | 1974-06-14 |
FR2207016B1 (en) | 1975-10-31 |
IT973002B (en) | 1974-06-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0301189B2 (en) | Method and apparatus for manufacturing a ribbed plastic pipe | |
EP0429862B1 (en) | Centering apparatus for a tube extruder head | |
DE2950003C2 (en) | Process for regulating the film thickness on a blown film extruder | |
DE19538255A1 (en) | Injection moulding of long fibre reinforced thermoplastic | |
DE2456986B2 (en) | DEVICE FOR CALIBRATING AND COOLING OF EXTRUDED PLASTIC PIPES | |
EP0600214A1 (en) | Method and apparatus for the continuous manufacturing of a composite pipe having a substantially smooth external wall portion | |
DE2706085C2 (en) | Device for extruding pipes made of thermoplastic material | |
DE2029969A1 (en) | Method and device for producing a polymer foam and for applying the same to wire or the like | |
DE4408064C1 (en) | Device for calibrating the outside diameter of a continuously extruded pipe | |
DE1778471C3 (en) | Method and apparatus for producing a composite body by coextrusion | |
DE2522357B2 (en) | Blow extruder | |
DE1421700C2 (en) | Process for the production of optical fibers | |
DE2313950A1 (en) | SCREW EXTRUSION PRESS FOR PLASTIC PIPES | |
DE2359746A1 (en) | METHOD FOR MANUFACTURING PIPE ELBOWS FROM THERMOPLASTIC PLASTIC AND DEVICE FOR CARRYING OUT THE METHOD | |
DE2221727C3 (en) | Device for calibrating a winding tube made of thermoplastic material | |
DE2031721A1 (en) | Method and device for producing rubber profiles | |
DE2706927C3 (en) | Plant for the production of plastic profile strands | |
EP0594018A1 (en) | Extrusion appparatus for plastic profiles | |
DE4135339C2 (en) | ||
EP0400281B1 (en) | Device for continuously jacketing cylindrical workpieces with elastic material | |
DE921063C (en) | Process for the production of dimensionally accurate long bores with the same length or changing diameters | |
DE2439957A1 (en) | METHOD AND DEVICE FOR COLD ROLLING PARALLEL PROFILES E.g. OF TOOTH PROFILES FROM THE FULL MATERIAL | |
AT393808B (en) | TOOL FOR PRODUCING TUBES WITH DIFFERENT WALL THICKNESSES | |
DE1943549A1 (en) | Wire-reinforced plastic tubes of helically - wound longitudinally overlapping extruded | |
DE1236173B (en) | Press head with an annular gap nozzle for the production of plastic foils |