DE10139324A1 - Extruded plastic strand guide system for a plastics granulation plant can be moved between two positions, one which feeds a production granulator and another which feeds a waste granulator - Google Patents

Abstract

A first fluid-flushed conveyer(3) cools and transports extruded plastic strands(KS) to a first granulator(50). A second conveyer(10) cools and transports extruded plastic strands to a second granulator(60). A variable position guide(2) alternates between two positions. In one position melt strands are fed to one of the conveyers while in the other position the other conveyer is supplied. A plastics granulating plant including the guiding system has conveyers feeding a production granulator and a waste granulator. Preferred Features: In its first position the strand guide directs strands onto the conveyer feeding the production granulator and in the second position of the guide strands pass the guide and fall onto the conveyer feeding the waste granulator. Alternatively in the second position of the guide the strands are directed to the conveyer feeding the waste granulator and in the first position strands pass the guide and fall onto the conveyer feeding the production granulator. In another variation both positions of the guide direct strands onto the appropriate conveyer.

Description

Device for use in a plastic strand pelletizer, the one with cooling liquid flushed transport device for cooling and transporting molten plastic strands a downstream granulator and a guide device, which between an operating position and a starting position like this is relocatable that the in one of the two positions Catches plastic strands and directs them in a desired direction.

There are currently two variants of these, mostly in combination with one rigid, inclined drainage channel flushed with coolant used guide device available on the market, namely so-called dissipative and incoming guiding devices, sometimes also as "dissipative Schurre "and" incoming chute "referred to.

For the derivative guiding device, it is characteristic that it Starting up the plastic strand pelletizing system ("start-up phase") catches molten plastic strands emerging from nozzles and derives ("start position"). Such a dissipative guide device is known for example from DE-AS-22 30 187. The derived ones Plastic strands form a tangle of waste strands, which however is difficult to handle. When changing over from the start-up phase of Plastic strand pelletizer in its operating phase, the Guiding device shifted from its starting position so that the Plastic strands directly onto the transport device for cooling and Transporting the plastic strands to the downstream granulator fall ("operating position").

The supplying guide device (DE-C-32 05 052), on the other hand, sees this before, the plastic strands during the operating phase of the Detect plastic strand pelletizing system and forward it to the transport device ( "Operating position"). In the start-up phase of In contrast, the plastic strand pelletizer is relocated so that the Plastic strands fall freely past the gutter and a waste cake form ("start position"). But also the handling of the waste cake is problematic because it is sawn into slices for disposal must be so that the material is melted down again and can be reused if necessary.

The object of the present invention is therefore to provide a device for Propose use in a plastic strand pelletizer which the during the start-up phase of Plastic strand pelletizer produced waste material is easier to handle.

This object is achieved by means of a device with the Features of claim 1 solved.

Accordingly, the device has in addition to that at the beginning mentioned transport device flushed with coolant for Cooling and transporting the molten feed Plastic strands to a downstream granulator, the following "Production granulator" is called, another, second with coolant flushed transport device, which the plastic strands in the start-up phase the plastic strand pelletizer to a second one Granulator transported, which is hereinafter referred to as "waste granulator".

The guide device is now between an operating position and one Starting position can be shifted so that it supplies the molten liquid Plastic strands in one of the two positions one of the two Transport devices and that in the other corresponding In both positions, the plastic strands corresponding to the other of the two Transport devices are supplied.

Both transport devices are preferably designed as inclined, water-flushed drainage gutter. One or both transport devices but can also be designed as a circumferential belt. Furthermore is preferably provided that the plastic strands when not of the guiding device and one of the two Transport devices are routed directly to the corresponding other Transport device fall and be transported further.

Accordingly, the preferred embodiment of the invention with "supplying guide device" that the guide device in their Operating position, that is, during the operating phase of the Plastic strand pelletizer, the plastic strands of those Feeds transport device that leads to the production granulator, and that the Plastic strands in the start position of the guide device, that is during the start-up phase of the plastic strand pelletizer, at the Guide device fall over onto the other transport device, which leads to the waste granulator.

The other preferred embodiment of the invention relates to the "derivative guiding device", in which the guiding device in its Start position, i.e. during the start-up phase of Plastic strand pelletizer, the plastic strands of that transport device feeds, which leads to the waste granulator, and in which the plastic strands in the operating position of the guide device, that is during the Operating phase of the plastic strand pelletizing system, on the guiding device fall over onto the other transport device which is used to Production granulator leads.

The above measures ensure that the Plastic strands in the start-up phase of the plastic strand pelletizer of the transport device that are fed to the waste granulator leads. Since this transport device is flushed with coolant, cool the plastic strands and can by means of the assigned Waste granulator immediately granulated and packed in waste granulate bags become. The quality of waste granules is usually not as good as the production granulate and need not be. The intensity of the Cooling the waste plastic strands is not critical, provided that Plastic strands are cooled until they can be granulated. Also the The quality of the knife edges of the waste granulator is immaterial. In particular, a waste granulator can be an outdated one Granulator model can be used.

An alternative embodiment sees a double-acting Guide device with which the plastic strands during the start-up phase of transport device leading to the waste granulator and during the Operating phase of the leading to the production granulator Transport device are supplied.

Of course, the waste granulator can also be the second Production granulator can be used, so that the guide device as a switch acts between two production lines.

The invention is described below with reference to the accompanying drawings described as an example. In it show:

Fig. 1 shows a first preferred embodiment of the present invention with "zuleitender guide"

Fig. 2 shows a second preferred embodiment of the invention with "dissipative guide device", and

Fig. 3 shows an alternative embodiment with double-acting guide device.

Fig. 1 shows a plastic strand with an extruder 1, from which the plastic strands KS molten escape and impinge on a "afferent" guide. 2 The plastic strand pelletizer in FIG. 1 is shown in its operating phase, that is, the afferent guide device 2 detects the plastic strands KS and forwards them to a conveying device 3 configured as inclined, rigid gutter. The guide device 2 is connected in the usual way to a water connection, and water (H ₂ O) flows over the surface of the guide device 2 further down the drainage channel 3 to a circulating conveyor belt 4 , the water taking the plastic strands KS with it. The cooling water is drawn off essentially completely at the lower end of the drainage channel 3 via a drainage device 5 . The conveyor belt 4 serves as a temperature compensation section, so that the temperature profile is homogenized over the cross section of the plastic strands before the plastic strands are fed to a granulator 50 for granulation there.

Instead of the circulating belt 4 , other assemblies for treating the plastic strands can also be provided. The circumferential belt 4 can also be completely omitted if necessary or can be equipped with additional elements such as blowing nozzles or water spray nozzles.

The guide device 2 can be shifted from the operating position shown in FIG. 1 into a starting position, not shown, preferably in the direction perpendicular to the plane of the drawing. With each shift from one position to the other position, the plastic strands KS are separated by means of a separating element, not shown. If, in the case of the plastic strand pelletizing system shown in FIG. 1 with the guiding device 2 to be fed in, the guiding device 2 is displaced perpendicularly to the image plane, the ends of the subsequent plastic strands automatically meet the second transport device 10 leading to a waste granulator 60 , which is also an inclined, rigid, water-flushed channel is formed. In the position of the guide device 2 then assumed, referred to as the start-up position, the plastic strands KS are thus granulated directly in the waste granulator 60 without a tangle of strands or a waste cake forming beforehand.

A corresponding plastic strand pelletizing system is shown in FIG. 2, but in which the guide device 2 is designed as a “diverting” guide device. The plastic strand pelletizing system is shown in its start-up phase in this case, that is to say the plastic strands KS emerging from the extruder 1 in molten form hit the surface of the guide device 2 and are carried along by the cooling water (H ₂ O) and fed to the transport device 10 which holds the plastic strands in the example shown, fed directly to the waste granulator 60 .

As soon as the plastic strands KS have the desired consistency, the guide device 2 is moved out of its starting position shown in FIG. 2, preferably in a direction perpendicular to the image plane, the plastic strands KS being cut simultaneously by means of a separating knife, again not shown. The ends of the subsequent plastic strands then fall vertically down directly onto the water-flushed drainage channel 3 and, as explained above in connection with FIG. 1, are fed to the production granulator 50 .

In the embodiment shown in FIG. 2, therefore, neither a tangle of strands nor a waste cake forms during the start-up phase of the plastic strand pelletizing system.

The assemblies of the plastic strand pelletizing system shown in FIGS. 1 and 2 are only shown schematically, since they are customary, customary assemblies for any person skilled in the art. This applies in particular to the guide device 2 .

An alternative embodiment with a double-acting guide device 2 is shown by way of example in FIG. 3, which shows the plastic strand pelletizing system in its operating phase. Similarly as in the embodiment of FIG. 1, the molten fed from the extruder 1 the plastic strands KS fall on an inclined plane of the guide device 2 and are taken away by cooling water (H ₂ O) to the gutter. 3

The guiding device 2 is longitudinally displaceable in the direction of the double arrow between the operating position shown and a starting position, not shown. During the transition from the operating phase to the start-up phase or vice versa, the plastic strands KS are first cut off using a cutting knife (not shown) and before the subsequent plastic strands hit the guide device 2 , the guide device 2 is shifted into the corresponding other position. The guide device 2 has two cooling water channels 6 , of which, depending on the positioning of the guide device 2 , only one cooling water channel 6 is connected to the cooling water supply line 7 . It is thereby achieved that the side of the guide device 2 which is currently performing a plastic strand-guiding function is rinsed with cooling water. Thus, when the guide device 2 is shifted from the operating position shown in FIG. 3 to the right into its starting position, the coolant supply line 7 is automatically connected to the coolant channel 6 of the guide device 2 and the plastic strands KS are supplied with the cooling water to the drainage channel 10 leading to the waste granulator 60 ,

Also in Fig. 3, the guide 2 is shown only schematically. The detailed design is at the discretion of the specialist.

Claims (5)

1. Device for use in a plastic strand pelletizing system, comprising a first transport device ( 3 ) flushed with coolant for cooling and transporting melted plastic strands (KS) to a first granulator ( 50 ) downstream of the device in a first operating phase of the plastic strand pelletizing system and a second one Transport device ( 10 ) for cooling and transporting the molten plastic strands (KS) to a second pelletizer ( 60 ) downstream of the device in a second operating phase of the plastic strand pelletizing system, as well as a guide device ( 2 ) that is between a first position and a second position It is displaceable that they supply molten plastic strands (KS) in one of the two positions of one of the two transport devices ( 3 , 10 ) and in the other of the two positions of the corresponding other of the two transport systems devices ( 3 or 10 ). 2. Device according to claim 1, characterized in that the guide device ( 2 ) in its first position, the plastic strands (KS) of the first, to the first granulator ( 50 ) leading transport device ( 3 ) and the plastic strands (KS) in the second position the guide device ( 2 ) past the guide device ( 2 ) onto the second transport device ( 10 ) ( FIG. 1). 3. Device according to claim 1, characterized in that the guide device ( 2 ) in its second position, the plastic strands (KS) of the second, to the second granulator ( 60 ) leading transport device ( 10 ) and the plastic strands (KS) in the first position the guide device ( 2 ) past the guide device ( 2 ) onto the first transport device ( 3 ) ( FIG. 2). 4. The device according to claim 1, characterized in that the guide device ( 2 ) in its second position, the plastic strands (KS) of the second, to the second granulator ( 60 ) leading second transport device ( 10 ) and that the guide device ( 2 ) in their In the first position, the plastic strands (KS) are fed to the first transport device ( 3 ) leading to the first granulator ( 50 ) ( FIG. 3). 5. Plastic strand pelletizing system comprising a device according to one of claims 1 to 4 and a production granulator ( 50 ) assigned to the first transport device ( 3 ) and a waste or production granulator ( 20 ) assigned to the second transport device ( 10 ).