DE20221671U1 - Launch system for application with extruder that has housing in which worm extrude is located and has coupling head linked to pull device and has clamping device to fix melt from extruder - Google Patents

Abstract

The launch system (1) for extruder (2) that has an extruder housing in which a worm extruder is mounted, consists of a coupling head (12) for capturing exiting melt from the extruder. There is a pull device (14) linked to the coupling head and which operates in the direction of future discharge direction. The pull device may be a cord, chain or pipe and may comprise a thread. The coupling head may have a clamping device for fixing the melt. The extruder may have a pipe head (3) through which the melt exits in the form of a pipe (18) and whose front end is coupled with the coupling head. The coupling head may have a cylindrical projection (16) for coupling and supporting the melt pipe.

Description

The The present invention relates to a launching system for use in an extruder according to the preamble of claim 1.

The Extrusion of plastic parts usually takes place in an extrusion line, for example, an extruder, a tool, a calibration device and / or a cooling device, a trigger device and optionally a separator includes. Here, the emerging from the tool molding under Forced to cool and calibrated. This is especially true in the extrusion of Hollow profiles and pipes of outstanding importance, since the extruded Mold is still plastic and thus unstable upon emergence. in the Regarding the dimensions as well as stresses that occur during cooling in can form the wall of the extruded molding, the calibration comes one special importance. Extruded hollow parts become predominantly from the outside calibrated, with the so-called vacuum tank calibration prevailed Has. This comprises a vacuum tank as a vacuum-tight lockable cooling basin, within which a calibrator is attached, which serves the shaping, and by the directly after the exit from the tool yet plastic melt tube of the extruded hollow part is pulled. The calibrator can - depending on the type of thermoplastic used - for example, as a sleeve or Disc calibrator executed be. The for the fixation of the shape of the molten tube necessary contact pressure to the calibrator is characterized by a pressure difference between the interior the hollow part, in which normally normal pressure prevails, and the Vacuum generated in the vacuum tank. The cooling pool can be equipped with spray nozzles be sprayed through the water on the molten tube to to cool it.

The Hollow parts need after leaving the calibration section, be sufficiently cool that they are suitable for the the extrusion line subsequent stresses sufficiently dimensionally stable are. To ensure this, can after the vacuum tank calibration still an additional Cooler, such as a so-called spray bath, be provided. at The said subsequent stresses are, for example a withdrawal device, the uniform onward transport of the extruded Profils or pipe is used by the extrusion line, and in the often caterpillars to Use come. These are occupied by caterpillars studded with rubber knobs Contact pressure applied to the extruded profile or tube, by means of which it furthers becomes. In addition, you can Winder or separating devices may be provided, of which the profile or tube in transportable Units are taken together or separated.

The already mentioned Deduction device should the melt strand smoothly and smoothly through the calibration and the cooling tanks pull, and thus ensure a consistent product quality. Here it must by means of the pull-off force in the previous Facilities occurring frictional forces caused by the contact pressure of the strand to the calibrator and the seals will compensate. But this continuous stripping can only in continuous operation, if the extruded profile or pipe at least the length has that it is engaged with the trigger device.

One general problem therefore lies in approaching an extrusion line, when the melt strand exiting the extruder is first calibrated and cooling devices sluiced and must be introduced into the trigger device.

Extrusion lines are known in which a vacuum tank calibration for calibrating a hollow plastic profile can be opened at the top, while at the same time liquid seals, which serve to seal the vacuum tank used, are designed such that they can be opened when starting up. Thus, the profile start due to the better accessibility of the interior of the Vakuumtankkalibrierung be additionally threaded through the device or pulled through with additional lower load. Only after the insertion is transferred to the control mode, ie the calibration parts and the vacuum tank are closed and the seal filled with water, so that a corresponding vacuum can be applied to the vacuum part. Such an extrusion line is in the DE 36 18 656 shown. Apart from the greater design effort for the production of resealable calibration and vacuum devices as well as the complex operation of the liquid seals, the disadvantage of this extrusion line in the complex manual operation is to be seen, because the profile must be threaded through the individual devices by hand. Already with only slightly increasing profile diameter this is not to be handled by a single person, since the meter weights of extruded profiles grow strongly with the diameter.

On the other hand, when starting an extrusion line, in particular a pipe extrusion line, it is customary to weld the melt leaving the tool, in this case a pipe head, to a pipe which is already in line. This so-called approach tube must be in advance over the entire length of the line in reverse direction. It may therefore have to be performed by a possible separator, a trigger, a cooling device and a vacuum tank to be present when starting the extruder directly after the pipe head for welding the emerging from the extruder melt tube. This backward insertion is very cumbersome, especially for pipes above a diameter of about 250 mm, since here the meter weights are very large and at the same time the internals located in the individual devices must not be damaged. In addition, since a vacuum in the Vakuumkalibriervorrichtung is to be generated as early as possible in order to minimize the so-called start-up loss, ie the rejection of generated pipe, it is necessary in this start-up for a pipe extrusion line that the approach pipe the same outer diameter as the one to be produced Pipe owns, since only at a time at which there is still a part of the Anfahrrohres in the vacuum tank, a vacuum can be effectively applied. In order additionally to optimize the welding process between the starting pipe and the extruded melt tube, the starting pipe and the melt should be made of the same or at least a similar thermoplastic material, since otherwise the weld joining the starting pipe and the melt tube will not have the required strength to transmit the necessary peeling force , Thus, the pipe producer must stockpile a suitable starting pipe for each pipe dimension to be produced and for each starting material used. Since a gentle backward insertion in approach tubes of correspondingly large diameter due to the high weight of several kilograms, taking into account a line length of about 50 m is absolutely no longer possible, in practice compounds of different thickness pipes are used to start an extrusion line. Here, a tube of the diameter to be produced is introduced only in the Vakuumtankkalibrierung, to this a tube of smaller diameter is connected, which z. B. can be done via a cable connection, and to this more pipe sections can be coupled with decreasing diameter, so as to facilitate insertion and to reduce the probability of damage to the facilities. The disadvantage of this, however, is that the trigger first acts on a tube of smaller diameter, which then abruptly and possibly repeatedly passes into a larger diameter tube, until finally the tube is detected with the diameter corresponding to the pipe diameter to be delivered. At these transition points occur due to the abrupt change in diameter heavy load on the triggering devices, generally caterpillars that can damage them. In addition, no continuous conveying can be ensured during this time.

outgoing from the problems described above, which inter alia in the difficult handling, the risk of damage during the starting process and the disadvantage that big ones Quantities of Anfahrrohren need to be stocked, it is the task the present invention, the startup process of an extrusion line, In particular, to simplify a pipe extrusion line, with particular Value on ease of use, low possibility of damage to existing equipment as well as possible short start-up committee is placed in the product to be produced. In addition, it should be avoided that large stocks of starting pipes provided Need to become.

These The object is achieved by a starting system according to the features of the claim 1 solved.

This Anfahrsystem can in an extrusion line with an extruder for Use come, which includes an extruder housing, in which at least one Extruder screw is added to the material to be processed plasticized and homogenized, wherein at one end of this extruder housing the processed Material as a melt in predefined form, preferably by an intermediate tool is reached, exit. By the use of a coupling head, which emerges from the extruder Melt detected, and then from one with this coupling head connected traction device together with the melt in the direction of a later Discharge direction of the extrusion line, as this example, by a deduction device provided in the line is specified, is deducted, leaves to provide a simple and effective start-up system, that solves the above problems.

The Traction device preferably comprises a rope, or at high occurring tensile forces a chain or a hose to the pull-off force on the coupling head transferred to, The connection between the rope and the head can, for example, via a appropriately trained eyelet respectively. By means of a winch, from which applied the withdrawal force and who is attacking the rope, the chain or the hose, For example, the coupling head may be along the production direction of the extrusion line subtracted from.

In order to facilitate the detection of the melt emerging from the extruder through the coupling head, a clamping device for fixing the melt to the coupling head can be provided. However, it is also possible to provide other types of connection between melt and coupling head, such as a melting of the still hot melt on a Ankopp ment head provided similar material.

In A particularly preferred embodiment is the coupling head substantially rotationally symmetric to the later withdrawal direction, d. H. also to the instantaneous pulling direction and thus to a longitudinal axis of fusion educated. It is particularly advantageous if the coupling head a plug-shaped Takes shape, for example, in the pipe extrusion in the Cross section may have a champagne cork comparable shape.

Especially suitable is a starting system according to the invention can be used in an extrusion line, which is used for pipe production. Here is provided as a tool a pipe head, from the melt emerges in the form of a molten tube. The front end of this Melting hose must be used when approaching the line with the coupling head couple. For this purpose, the coupling head preferably has a cylindrical Lead on, around which the still plastic melt tube can attach when coupling and by which he is supported. This is special advantageous if the diameter of the cylindrical projection in essentially corresponds to the inner diameter of the molten tube.

Around a slight coupling of the melt tube to the coupling head to enable by so-called "welding" In this case, it is advantageous if the cylindrical projection is formed by a pipe section made of the same or at least a similar one Material, how the processed melt is made. By "welding" means the Connection that's still hot and plastic melt tube with the underlying tube section due to a merger process, and usually so It is good that you can do without further fixatives.

In an extrusion line for the production of pipes comes into connection to the pipe head usually a calibration device is used, of which the still thermoplastic Melt tube the desired Tube dimensions are given, which is fixed by additional cooling become. By appropriate action otherwise in the pipe wall occurring voltages can be avoided. Particularly preferred as a calibration device a vacuum tank calibration provided the tube of length goes through and in it from the outside is calibrated by creating a pressure difference between Pipe interior and a vacuum tank calibration against a calibration device depressed and meanwhile chilled becomes. After passing the calibration section, the melt tube must further cooled until it is sufficiently dimensionally stable, this is usually done on more Coolers, such as tanks with water baths or spray nozzles.

In a starting system according to the present invention Invention should be when starting an extrusion line of the molten tube be guided exactly along the way by means of the coupling head, which he should also take in continuous operation. The coupling head with The melt tube should therefore also by the calibration be drawn, whose inner diameter is exactly the outer diameter corresponds to the tube to be produced. That is why it is advantageous if the outside diameter of the tube to be produced coincides with an outer diameter of the coupling head, which then at the same time corresponds to the diameter of the calibration device. Particularly preferably, the coupling head is designed so that he while the coupling process, so for example during the welding of the Melt tube to the cylindrical projection or the cylindrical Pipe section, is kept centered by the calibration device. This is possible For example, achieve that at least a portion of the Coupling head, which is during of welding located in the calibration device, in the direction of the withdrawal direction has the same diameter as the tube to be produced.

Around the coupling of the exiting the extruder melt to the To further facilitate coupling head, it is advantageous to directly following the tube head a supporting device for the exiting To provide melt. This support device Can be flanged directly to the pipe head or otherwise secured be, and prevents any drainage of the still thermoplastic melt due to gravity. For this purpose, the supporting device essentially hollow cylindrical be formed, or the shape of a substantially in the lower Have the region of the tube head mounted half-shell.

In order to enable as early as possible a calibration of the molten tube by the vacuum tank provided in the vacuum tank calibration calibration, in a particularly preferred embodiment of the coupling head is designed such that the coupling between the emerging from the extruder melt and the coupling head is substantially airtight. It can then be provided a compressed air supply, which generates an overpressure in the melt tube interior, which is formed between the pipe head and coupling head. As a result, the still plastic melt is already pressed against the calibration device, before a vacuum can still be applied to the vacuum tank. This is the case, for example, when the coupling head is still in the calibration device, and the Va vacuum tank is therefore not completely sealed against the environment.

Especially the compressed air supply is preferred through the stationary Extruder head done. Advantageously, an additional Control device provided by means of which the pressure regulated in the pipe and to the procedural requirements can be adjusted. Once the produced pipe length the Length of the Vacuum tanks exceeds, i.e. as soon as the coupling head leaves the vacuum tank calibration vacuum can be applied in the vacuum tank, and the overpressure be adjusted in the pipe interior to the normal pressure. The vacuum tank calibration can then continue to operate in the usual way in continuous operation be while the coupling head by means of the pulling device by in the Extrusion line possibly subsequent coolers and a subsequent extraction device is pulled. in this connection make sure that the pulling device is smooth, without Jerkiness and at the same speed as in the later continuous production is working.

As soon as the coupling head, and with it the hose connected to it or pipe end that has passed the trigger, the operation is the extrusion line from a start-up phase into permanent production. The Pull-off force can then from the trigger device to the at this Place already sufficiently stable pipe in the extrusion line be, the traction device is no longer necessary.

For the whole Extrusion line is preferably provided a control, which controls the individual elements of the extrusion line, and each other tunes. To this controller can for example, in addition to the extruder, the pulling device, the trigger device and the calibration device be connected, as well as advantageously the Compressed air control device.

A particularly advantageous embodiment of the present invention will be explained in more detail with reference to the following drawings.

It demonstrate:

1 : An exemplary extrusion line, in which an embodiment of the starting system according to the invention can be used, and

2 : A schematic longitudinal section through a tube head including subsequent calibration device with introduced coupling head and welded melt tube.

In 1 is a typical extrusion line 1 shown schematically having exemplary elements, but certainly have additional facilities or can do without such. An extruder 2 with material supply is right in the picture, directly to this extruder 2 closes a pipe head 3 on, through which the extruder 2 emerging thermoplastic melt is formed into a molten tube. Directly after the pipe head 3 there is a vacuum tank calibration 4 in which the still plastic melt tube is pressed against an inner wall of the calibration device and thus calibrated due to a pressure difference between the tube interior under normal pressure and a negative pressure generated in the vacuum tank. In this vacuum tank calibration 4 For example, cooling devices such as spray nozzles may be provided in addition to cooling the melt. After the outlet of the calibrated melt tube or pipe 8th from the vacuum tank calibration 4 goes through the still warm pipe 8th other cooling devices 5 such as cooling tanks or spray baths. Here is the tube 8th cooled down so that it is sufficiently dimensionally stable for subsequent use. On the cooler 5 follows a caterpillar deduction 6 , the melt strand or pipe 8th jerk-free and at a constant speed through the calibration device and the cooling tanks, as well as the already cooled pipes 8th to the rear through a separator 7 promotes. Here, the withdrawal force of the caterpillar take-off must 6 be chosen so that it is greater than the friction forces occurring in the line, as z. B. by pressing the melt tube to the calibrator or seals that isolate the vacuum tank of the calibrator against the environment occur. On the separator 7 in which the endless tube produced 8th separated into individual pipe sections, z. B. sawn, followed by a storage device 9 ,

In continuous operation is in such an extrusion line 1 the withdrawal force through the trigger 6 on the pipe 8th and thus also on the associated, still plastic melt in the calibration device 4 and the cooling device 5 transfer. During the start-up process of such an extrusion line 1 However, the still plastic melt tube, which has to be removed from the tube head 3 exit, only so far be led by the line, until the departure 6 can affect him. Once this is done, the operation goes into continuous operation.

In 2 is a section of the above-described extrusion line 1 during the starting process shown schematically in cross section. On the left is a pipe head 3 to see, in the direction of production, ie in the figure to the right, a partially illustrated calibration 4 followed. Inside the calibration device is a coupling head 12 recorded, whose Au ßenkontur coincides with the inner contour of the calibration. In the case of pipe extrusion with a hollow cylindrical calibration device, the coupling head 12 at least partially a cylindrical outer contour 15 which allows the coupling head 12 centered in the calibration device 4 to hold. Along the conveying or withdrawal direction of the extrusion line 1 acts on the coupling head 12 a pulling device 14 comprising a cable connected to a cable winch, at the coupling head 12 attached via an eyelet. On the tube head 3 opposite side of the coupling head 12 this has a cylindrical projection 16 on, whose outer cross section substantially corresponds to an inner cross section of the tube to be produced. This cylindrical projection 16 is formed by a tube segment made of a material similar to the melt. The exact design of the coupling head 12 is arbitrary, but can, as in the 2 , Essentially stuffed or cork shape. At the exit of the pipe head 3 is a substantially hollow cylindrical support device 20 attached, whose inner diameter corresponds to an outer diameter of the tube to be produced, and a sagging of the still thermoplastic melt due to gravity directly after exiting the tube head 3 prevented. Through the pipe head 3 is a compressed air supply 22 guided, which ends in an interior of the pipe to be produced.

Before starting an extrusion line 1 according to 1 becomes a coupling head 12 in a calibration device 4 introduced that it is stored there centric and requires no further support. This introduction will normally occur contrary to the later conveying direction of the extrusion line. The cylindrical projection 16 of the coupling head according to the invention 12 Close at this time almost directly to the output of the tube head 3 at. About a rope is the coupling head 12 connected to a not shown winch. The rope runs through the entire line 1 ie by separating device, extraction device, possibly cooling devices and the calibration device along the melt path. The winch is centrally located after the mentioned facilities.

When starting the extruder 2 is through the pipe head 3 a molten tube 18 shaped, whose front end is around the cylindrical projection 16 of the coupling head 12 outsourced. Here it can either be fixed by a clamping device, but is preferably the embodiment in which the cylindrical projection 16 consists of the same or a similar material as the melt, since then takes place due to the heat of the thermoplastic molten tube, a so-called welding, ie, melt tube and pipe section 16 connect firmly by melting. As soon as the melting has led to a sufficiently firm fusion seam, the pulling device pulls 14 the coupling head 12 together with the continuously produced melt tube 18 evenly and smoothly through the calibration device 4 and the following devices of the extrusion line 1 along the usual pipe or melt passage. Here, the train speed must be exactly to the production rate of the molten tube 18 be turned off.

In between melted tube 18 , Extruder head 3 and coupling head 12 resulting interior becomes with the start of the extrusion line 1 by a compressed air supply 22 generates an overpressure. This allows the vacuum tank calibration 4 already act as a calibrator due to the pressure difference between the tube interior and the vacuum tank, although no vacuum can be applied to them until the coupling head is reached 12 her entire length has happened. This allows a reduction of the reject line 1 when starting.

The compressed air supply 22 will as well as the vacuum tank calibration 4 , in the vacuum tank, a vacuum can be generated as soon as the coupling head 12 from the calibration 4 exiting, regulated by a common control, not shown.

As soon as the coupling head 12 together with the welded pipe end also the caterpillar take-off 6 has happened, this can take up his work, and on the pipe 8th act in such a way that the withdrawal force, until then on the traction device 14 was applied by him in the pipe 8th is initiated.

The starting process is hereby finished and the permanent production can be recorded. Due to the already early onset of calibration due to the overpressure build-up inside the hose, it becomes possible to approach the extrusion line 1 to produce only a small amount of scrap, which is essentially the length of the coupling head 12 equivalent.

The present invention thus makes it possible to use an extrusion line 1 easy to drive while avoiding damage to the individual, in-line devices with low rejects.

1

extrusion line

2

extruder

3

pipehead

4

Vacuum calibration

5

cooler

6

Raupenabzug

7

separating device

8th

pipe

9

depositing device

12

coupling head

14

hitch

15

cylindrical outer contour

16

cylindrical head Start

18

melt tube

20

Support device

22

Compressed air supply

Claims (28)

Starting system for use with an extruder ( 2 ), comprising an extruder housing, in which at least one extruder screw is received, wherein melt processed at one end of the extruder housing exits in a predefined form, characterized in that a coupling head ( 12 ) for detecting the extruder ( 2 ) emerging melt and one with the coupling head ( 12 ) connected pulling device ( 14 ) are provided, wherein the pulling device ( 14 ) acts in the direction of a later withdrawal direction. Starting system according to claim 1, characterized in that the pulling device ( 14 ) comprises a rope, a chain or a hose. Starting system according to claim 1 or 2, characterized in that the pulling device ( 14 ) comprises a winch. Starting system according to one of claims 1-3, characterized in that the coupling head ( 12 ) has a clamping device for fixing the melt. Starting system according to one of claims 1-4, characterized in that the coupling head ( 12 ) is formed substantially rotationally symmetrical to the later withdrawal direction. Starting system according to claim 5, characterized in that the coupling head ( 12 ) is formed substantially plug-shaped. Starting system according to one of claims 1-6, characterized in that an extruder ( 2 ) with a tube head ( 3 ) is provided, from which the melt in the form of a tube ( 18 ) emerges whose front end with the coupling head ( 12 ) couples. Starting system according to claim 7, characterized in that the coupling head ( 12 ) a cylindrical projection ( 16 ) for coupling and supporting the molten tube ( 18 ) having. Starting system according to claim 8, characterized in that the diameter of the cylindrical projection ( 16 ) substantially to the inner diameter of the molten tube ( 18 ) corresponds. Starting system according to claim 9, characterized in that the cylindrical projection ( 16 ) is formed by a pipe section. Starting system according to claim 10, characterized in that that the pipe section of the same or at least similar Material like the melt is made. Starting system according to one of claims 7-11, characterized in that following the pipe head ( 3 ) a calibration device ( 4 ) is provided to the from the extruder ( 2 ) exiting melt tube ( 18 ) to calibrate. Starting system according to claim 12, characterized in that as calibration device ( 4 ) a vacuum tank calibration is provided. Starting system according to one of claims 12 or 13, characterized in that an outer diameter of the coupling head ( 12 ) with the inner diameter of the calibration device ( 4 ) matches. Starting system according to one of claims 12-14, characterized in that the outer diameter of the coupling head ( 12 ) substantially with the outer diameter of the molten tube ( 18 ) matches. Starting system according to one of claims 12-15, characterized in that the coupling head ( 12 ) is designed so that it from the calibration device ( 4 ) is kept centered. Starting system according to one of claims 7-16, characterized in that on the pipe head ( 3 ) a supporting device ( 20 ) for the exiting melt tube ( 18 ) is provided. Starting system according to claim 17, characterized in that the supporting device ( 20 ) is formed substantially hollow cylindrical. Starting system according to claim 17, characterized in that the supporting device ( 20 ) in the essentially as in the lower part of the pipe head ( 3 ) attached half-shell is formed. Starting system according to one of claims 7-19, characterized in that it is designed such that the coupling between the coupling head ( 12 ) and from the extruder ( 2 ) exiting melt ( 18 ) is substantially airtight. Starting system according to claim 20, characterized in that a compressed air supply ( 22 ) is provided in the between pipe head ( 3 ) and coupling head ( 12 ) cavity to create an overpressure. Starting system according to claim 21, characterized in that the compressed air supply ( 22 ) through the extruder head ( 3 ) is guided. Starting system according to claim 21 or 22, characterized a control device is provided for regulating the overpressure in the cavity is. Starting system according to one of claims 7-23, characterized in that following the calibration device ( 4 ) a trigger device ( 6 ) is provided, which dictates the withdrawal direction. Starting system according to claim 24, characterized in that as a take-off device ( 6 ) A caterpillar take-off is provided. Starting system according to one of claims 7-25, characterized in that a control is provided which the extrusion line ( 1 ) and the pulling device ( 14 ) controls. Coupling head for use in a starting system according to any one of claims 1-26, characterized in that the coupling head comprises a first element for detecting the from an extruder ( 2 ) emerging melt and a second, the first element opposite element for connection to the pulling device ( 14 ) having. Coupling head according to claim 27, characterized in that a region located between the elements for the purpose of connection or joining is provided, which extends along the direction of the pulling device ( 14 ) has substantially constant cross section, said cross section corresponds to the outer cross section of the exiting melt.