DE2043129A1 - Photoelectric monitor for diameter of - blown tube - Google Patents
Photoelectric monitor for diameter of - blown tubeInfo
- Publication number
- DE2043129A1 DE2043129A1 DE19702043129 DE2043129A DE2043129A1 DE 2043129 A1 DE2043129 A1 DE 2043129A1 DE 19702043129 DE19702043129 DE 19702043129 DE 2043129 A DE2043129 A DE 2043129A DE 2043129 A1 DE2043129 A1 DE 2043129A1
- Authority
- DE
- Germany
- Prior art keywords
- bladder
- gas
- gas supply
- gas discharge
- control valve
- 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
- B29C2948/92247—Optical properties
-
- 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
- B29C2948/92514—Pressure
-
- 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
- B29C2948/926—Flow or feed rate
-
- 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
- B29C2948/92619—Diameter or circumference
-
- 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
- B29C2948/92923—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
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0018—Combinations of extrusion moulding with other shaping operations combined with shaping by orienting, stretching or shrinking, e.g. film blowing
-
- 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
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0019—Combinations of extrusion moulding with other shaping operations combined with shaping by flattening, folding or bending
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
Abstract
Description
Verfahren zur Herstellung von Blasfolien gleichmäßiger Wandstärke und gleichmäßigen Umfangs und Regelanordnung hiezu Die Erfindung betrifft ein Verfahren zur Herstellung von Blasfolien gleichmäßiger Wandstärke und gleichmäßigen Umfangs und eine Regelanordnung hiezu.Process for the production of blown films of uniform wall thickness and uniform circumference and control arrangement therefor. The invention relates to a method for the production of blown films of uniform wall thickness and uniform circumference and a control arrangement for this.
Endlosschläuche aus thermoplastischem Material müssen zur Verminderung ihrer Wandstärke bei Temperaturen unterhalb des Erveichungspunktes allseitig gedehnt verden. Die Dehnung quer zur Laufrichtung erfolgt dadurch, daß man den Endlosschlauch nach seinem Austritt aus dem Ringspalt aufbläst (vergl. z.B. österr.Patentschrift Nr.246 416 - 1966, Imperial Chemical Industries Ltd.) oder über einen kühlkörper zieht (vergl. z.B. US-PatentschriEt Nr. 2 720 680 - 1955, M.R.Gerow).Continuous tubing made of thermoplastic material must be used to reduce their wall thickness stretched on all sides at temperatures below the softening point verden. The stretching transversely to the running direction takes place by the fact that the endless tube inflates after it emerges from the annular gap (see e.g. Austrian patent specification No. 246 416 - 1966, Imperial Chemical Industries Ltd.) or via a heat sink draws (see e.g. U.S. Patent No. 2,720,680-1955, M.R. Gerow).
In beiden Fällen muß in der Schlauchblase, d.h. entweder in dem Raume zwischen dem Ringspalt und den Quetschwalzen, die das Flachlegen bevirken, oder in dem Raume zumischen dem Ringspalt unidem kühlkörper eine sehr genaue konstante Druckdifferenz gegen die Außenluft aufrecht erhalten werden; die Blase verliert nämlich dauernd Gas durch die Quetschwalzen, da man diese nicht so stark aneinanderpressen kann, daß sie vollständig dicht halten. Der Uberdruck im Inneren der Blase soll um 5 kp/m2 liegen (50 N/m2). Verarbeitet man nun Rohstoffe, wie z.B. Polypropylen oder Polypropylencompounds, die unter den Verpreßbedingungen Gase oder Dämpfe abgeben (Weichmacher, Stabilisator oder deren Zersetzungsprodukte), oder will man die Blase auch von innen mit Luft oder Gas kühlen, so ist nicht nur der Uberdruck in ihr konstant zu halten, sondern auch gleichzeitig ihr Inneres intensiv zu spülen, d.h. die Luft oder das Gas ist miL verhältnismäßig großer Geschwindigkeit zu wechseln. Andernfalls kondensieren sich die Zersetzungsprodukte innen an den kühleren Stellen der Blase und rufen Störungen hervor, wie z.B. Blocken, trübe Stellen oder Lochbildung. Die gleichzeitige Aufrechterhaltung der Druckkonstanz und die Ausführung der Spülung sind besonders im Dauerbetrieb schwierig.In both cases it must be in the bladder tube, i.e. either in the space between the annular gap and the nip rollers that cause the flattening, or in the room, the annular gap and the heat sink mix a very precise constant Pressure difference be maintained against the outside air; the The bubble is constantly losing gas through the squeegee rollers, because they are not so can press together strongly that they hold completely tight. The overpressure in the The interior of the bubble should be around 5 kp / m2 (50 N / m2). If you now process raw materials, such as polypropylene or polypropylene compounds, which under the compression conditions Give off gases or vapors (plasticizers, stabilizers or their decomposition products), or if you also want to cool the bladder from the inside with air or gas, that's not all the overpressure in her to keep constant, but also to keep her interior intense at the same time to purge, i.e. the air or the gas is at a relatively high speed switch. Otherwise the decomposition products will condense on the inside cooler parts of the bladder and cause disturbances such as blocking, cloudy areas or hole formation. The simultaneous maintenance of the pressure constancy and the Execution of the flushing are particularly difficult in continuous operation.
Zweck der Erfindung ist das Vermeiden der beschriebenen Ubelstände.The purpose of the invention is to avoid the disadvantages described.
Es wurde nämlich gefunden, daß man mit hilfe einer einfachen lichtelektrischen Regelanordnung beide Maßnahmen ohne Schvierigt keit zugleich durchführen kann.It has been found that you can use a simple photoelectric Control arrangement can carry out both measures at the same time without difficulty.
Gegenstand der Erfindung ist demnach ein Verfahren zur Herstellung von Blasfolien gleichmäßiger Wandstärke und gleichmäßigen Umfangs bei gleichzeitiger Spülung des Innenraumes der Blase, das dadurch gekennzeichnet ist, daß die Menge des durch die Blase durchgeführten Blase- oder Spülgases über einen oder mehrere peripher um die Blase angeordnete lichtelektrische Fühler geregelt wird, indem bei Vergrößerung des Blasendurchmessers der Innendruck in der Blase durch Änderung des Gasdurchsatzes durch sie vermindert, bei Verringerung des Druckes aber vergrößert wird.The invention accordingly relates to a method of production of blown film of uniform wall thickness and uniform circumference with simultaneous Rinsing the interior of the bladder, which is characterized in that the amount of the blowing or purging gas passed through the bladder via one or more photoelectric sensors arranged peripherally around the bladder are controlled by at Enlargement of the bladder diameter by changing the internal pressure in the bladder Gas throughput reduced through them, but increased when the pressure is reduced will.
Die Regelung kann sovohl in die LuPt- oder Gaszuführung, als auch in die Abführung eingebaut werden, wobei sich natUrlich die Regelrichtung ändert. Ist die Spülgasmenge öfters in großen Bereichen zu ändern, so sind zweckmäßigerweise sowohl Gaszu- als auch Ableitung mit einem Regelventil zu versehen.The regulation can be carried out in the LuPt or gas supply as well as be built into the drainage, of course the control direction changes. If the amount of purging gas has to be changed frequently in large areas, it is advisable to do so to provide both gas inlet and outlet with a control valve.
Um die Symmetrie der Schwankungen zu wahren oder ein Hin-und Herpendeln der Blase zu berücksichtigen, können zwei oder noch mehr lichtelektrische Fühler regelmäßig rund um die Blase verteilt werden.In order to maintain the symmetry of the fluctuations or a back and forth oscillation To take into account the bladder, two or more photoelectric sensors can be used be spread regularly around the bladder.
Erfolgt die erfindungsgemäße Regelung nach einer bevorzugten Ausführungsform mit einer gewissen einstellbaren Totzeit, so kann man ein periodisches Atmen@ der Schlauchblase bewirken; bei kühlung durch einen inneren tUhlkörper erreicht man dadurch, daß der heiße Schlauch nicht immer auf dieselbe Zone des ühlkörpers auftrifft. Dadurch werden sehr bequem örtliche Uberhitzungen vermieden; die durch das Atmen verursachten Dickeschuankungen der Folie sind unerheblich.If the regulation according to the invention takes place according to a preferred embodiment with a certain adjustable dead time, you can have periodic breathing @ effect of the tubular bladder; achieved when cooled through an inner tube one by the fact that the hot hose is not always on the same zone of the heat sink hits. This very conveniently prevents local overheating; by Thickness fluctuations in the film caused by breathing are insignificant.
Je nach dem erforderlichen oder vertretbaren regeltechnischen Aufwand kann die Ausbildung des Reglers als Zvei- oder Dreipunktregler, P, PI oder PID-Regler erfolgen, so daß die Anordnung für einen festen oder einstellbaren Sollwert sowie für verschiedene Präzisionsstufen erstellt werden kann. Die Empfindlichkeit läßt sich theoretisch beliebig und für praktische Zwecke mehr als ausreichend steigern.Depending on the required or justifiable regulatory effort The controller can be designed as a two-position or three-position controller, P, PI or PID controller take place so that the arrangement for a fixed or adjustable setpoint as well can be created for different levels of precision. The sensitivity leaves increase theoretically at will and more than sufficiently for practical purposes.
Einige mögliche Ausführungsformen der Regelanordnung zur Durchführung des erfindungsgemäßen Verfahrens, die ebenfalls Gegenstand der vorliegenden Erfindung sind, zeigen Fig. 1 und 2 in Längs- und Querschnitt, während die Figuren 3, 4 und 5 Teilansichten im Querschnitt zeigen. Die Bezeichnungen im Text richten sich nach dem Normenblatt DIN 19 226; es bedeuten: 1 die Schlauchblase = Regelstrecke 2 die Lichtquelle = Eingabeglied 3 die Photozelle = Fühler 4 den Signalumformer = Meßun,former 5 den Regler 6 den Stellantrieb 7 das Regelventil n Stellglied ferner bedeuten: 8 den Ringspalt 9 die Ouetschwalzen 10 das Gaszuführungsrohr 11 das Gasabführungsrohr 12 die handbediente Drossel 13 Lichtstrahl = Signal Aus dem Ringspalt (8) tritt der Folienschlauch und wird zur Schlauchbiase (1) aufgeblasen; nach der endgültigen Formgebung wird er durch die Quetschwalzen (9) flachgelegt Der Folienschlauch wird vom Lichtstrahl (13) der Lichtquelle (2) streifend getroffen. Der Lichtstrahl (13) gelangt auf seinem weiteren Wege mehr oder weniger geschwächt auf die Photozelle (3), die über den Meßuinforrner (4) den Schwächungsgrad des Lichtstrahles (13), der vom Blasendurchinesser abhängt, als Regelsignal dem Regler (5) zuführt. Der Regler beeinflußt nun über den Stellantrieb (6) das Regelventil (7) ftir die Zufuhr des Blase- oder Spülgases Die Anordnung ist rovohl zum Durchblasen, als auch zum Durchsaugen von Luft oder Gas geeignet Fig. 3 zeigt die Regelanordnung für gleichbleibende Gasabfuhr Das Gaszuführungsrohr (10) enthält ein Regelventil (7), das Gasabführungsrohr (11) eine handbediente Drossel (12) Fig 4 zeigt die umgekehrte Anordnung; das Regelventil (7) ist im Gasabführungsrohr (11) eingebaut, während das Gaszuführungsrohr (10) eine handbediente Drossel (12) enthält Fig. 5 zeigt den Fall, daß sowohl Gaszuführungs- (10) als auch Gasabführungsrohr (11) ein Regelventil (7) enthalten, wodurch an kurzfristig eine Änderung des Gasdurchsatzes durch die Schlauchblase eingestellt werden kann.Some possible embodiments of the control arrangement for implementation of the method according to the invention, which are also the subject of the present invention 1 and 2 show in longitudinal and cross-section, while FIGS. 3, 4 and 5 show partial cross-sectional views. The designations in the text are based on the standard sheet DIN 19 226; it means: 1 the tube bubble = controlled system 2 the Light source = input element 3 the photocell = sensor 4 the signal converter = measuring unit 5 the controller 6 the actuator 7 the control valve n actuator also mean: 8 the annular gap 9 the Ouetwalzen 10 the gas supply pipe 11 the gas discharge pipe 12 the manually operated throttle 13 light beam = signal emerges from the annular gap (8) the film tube and is inflated to form the tube bubble (1); after the final Shaping it is laid flat by the nip rollers (9). The film tube is hit by the light beam (13) of the light source (2) grazing. The ray of light (13) on its further way reaches the photocell more or less weakened (3), which via the Messuinforrner (4) the degree of attenuation of the light beam (13), which depends on the bladder diameter, is fed as a control signal to the controller (5). Of the The controller now influences the control valve (7) for the supply via the actuator (6) of the blowing or purging gas The arrangement is rough for blowing through, as well as for Suction of air or gas suitable. Fig. 3 shows the control arrangement for constant Gas discharge The gas supply pipe (10) contains a control valve (7), the gas discharge pipe (11) a manually operated throttle (12) Figure 4 shows the reverse arrangement; the control valve (7) is installed in the gas discharge pipe (11), while the gas supply pipe (10) a manually operated throttle (12) contains Fig. 5 shows the case that both gas supply (10) as well Gas discharge pipe (11) contain a control valve (7), which leads to a short-term change in the gas throughput through the tube bladder can be adjusted.
Fig. 6 zeigt im Querschnitt eine mögliche Anordnung von 3 Lichtquellen (2) nebst Photozellen (3) und Meßumformern (4) um die Schlauchblase (1).6 shows a possible arrangement of 3 light sources in cross section (2) together with photocells (3) and transducers (4) around the tube bladder (1).
Mit dieser Regelanordnung lassen sich zum Beispiel bei Polypropylen im Dauerbetrieb störungsSreie Abzugsgeschiwindigkeiten bis zu 120 m/min und darüber bei 20 - 3l/um Dicke des Folienschlauches erreichen, gegenüber 30 - 40 m/min bisher, d.h.This control arrangement can be used, for example, for polypropylene Trouble-free take-off speeds of up to 120 m / min and more in continuous operation at 20 - 3 l / µm thickness of the film tube, compared to 30 - 40 m / min so far, i.e.
Geschwindigkeiten, bei den bereits die Leistung der Extruderschnecke der geschwindigkeitshemmende Umstand ist. Sie ist auch für die Herstellung von Schlauchfolien aus anderen Polyolefinen, insbesondere aus Hochdruck- und Niederdruckpolyäthylen geeignet.Speeds at which the output of the extruder screw is already possible the speed-inhibiting circumstance is. It is also used for the production of tubular films from other polyolefins, especially from high-pressure and low-pressure polyethylene suitable.
Die Anordnung läßt sich leicht an handelsüblichen Strangpressen (Extrudern) im Nachhinein anbringen.The arrangement can be easily carried out on commercially available extrusion presses (extruders) apply afterwards.
Claims (11)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT932369A AT304860B (en) | 1969-10-03 | 1969-10-03 | Process for the production of tubular films made of thermoplastic |
Publications (1)
Publication Number | Publication Date |
---|---|
DE2043129A1 true DE2043129A1 (en) | 1971-04-22 |
Family
ID=3613144
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19702043129 Pending DE2043129A1 (en) | 1969-10-03 | 1970-08-31 | Photoelectric monitor for diameter of - blown tube |
Country Status (2)
Country | Link |
---|---|
AT (1) | AT304860B (en) |
DE (1) | DE2043129A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0001111A1 (en) * | 1977-09-09 | 1979-03-21 | PANNENBECKER, Heinrich | Method and apparatus for manufacturing blown films |
FR2443094A1 (en) * | 1978-11-30 | 1980-06-27 | Gloucester Eng Co Inc | Automatic control of blown film tubing - in which light monitors tubing dia. and regulates valve for internal cooling air |
DE2951416A1 (en) * | 1978-12-25 | 1980-07-17 | Chisso Eng Co Ltd | DEVICE FOR THE PRODUCTION OF TUBULAR PLASTIC FILMS |
EP0522278A1 (en) * | 1991-07-08 | 1993-01-13 | WindmÀ¶ller & Hölscher | Process for controlling the diameter of tubular films produced in a blown film extruder installation |
-
1969
- 1969-10-03 AT AT932369A patent/AT304860B/en not_active IP Right Cessation
-
1970
- 1970-08-31 DE DE19702043129 patent/DE2043129A1/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0001111A1 (en) * | 1977-09-09 | 1979-03-21 | PANNENBECKER, Heinrich | Method and apparatus for manufacturing blown films |
FR2443094A1 (en) * | 1978-11-30 | 1980-06-27 | Gloucester Eng Co Inc | Automatic control of blown film tubing - in which light monitors tubing dia. and regulates valve for internal cooling air |
DE2951416A1 (en) * | 1978-12-25 | 1980-07-17 | Chisso Eng Co Ltd | DEVICE FOR THE PRODUCTION OF TUBULAR PLASTIC FILMS |
EP0522278A1 (en) * | 1991-07-08 | 1993-01-13 | WindmÀ¶ller & Hölscher | Process for controlling the diameter of tubular films produced in a blown film extruder installation |
Also Published As
Publication number | Publication date |
---|---|
AT304860B (en) | 1973-01-25 |
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