PROCEDURE AND DEVICE FOR THE REGULATION OF THE THICKNESS PROFILE DURING THE BLOWING FOIL PRODUCTION

The invention concerns a procedure for the regulation of the thickness profile with the production of Schlauchfolien and refers in addition to a device for the execution of this procedure. The extent thickness profile of the tubular sheeting withdrawing from the ring sensor of a blowing foil extrusion exhibits extent-distributes thicker and thinner ranges, which have a to a large extent stationary position. This unequal thickness distribution over the extent affects itself with rolling up and processing the tubular sheeting negatively.

In order to keep the deviations of the extent thickness profile as small as possible with the manufacture procedure, the effect is used that when blowing the tubular sheeting, i.e. with the expand of the hose diameter, warmer ranges more strongly and cooler ranges are less strongly equipped-hit a corner. With well-known devices the thickness differences of the Schlauchfolie over the extent are affected by variation of the cooling performance or by variation of the heating of the deflector.

During higher cooling performance to an extent extent the Schlauchfolie cools faster, so less strongly is stretched and keeps thus a relatively larger foil thickness. During smaller cooling performance to an extent extent the Schlauchfolie keeps a higher temperature, consequently she is more strongly flexible; thus the foil thickness is more strongly decreased. The foil thickness differences over the extent are determined here by a measuring device and conveyed to a controlling mean for the variation of the cool or amount of heat. This measuring instrument is usually in production direction behind a so-called freezing range of the foil material arranged, in which the foil material does not stretch any longer vividly.

Increased output achievements of modern blown film extrusion plants led rising requirements in the last years too constantly to the efficiency of thickness profile monitoring systems, since with increasing output achievements also the temperature inhomogeneities in the extruding part as well as the instabilities of the tubular sheeting within the range of the direct cooling gas supply increase, which leads again to larger heterogeneities in the thickness profile of the tubular sheeting over the extent.

From the DE 100 29 175 A1 a device is well-known for the regulation of the thickness profile with the production from Blasfolien to the use at the Blaskopf of a blowing foil extrusion, which a main cooling ring for a main cooling gas flow held over the extent constantly as well as one below the same arranged auxiliary cooling ring, are variable controllable sektorweise with which auxiliary cooling gas flows. The auxiliary cooling ring is here directly above the exhaust nozzle of the Blaskopfes. Above the main cooling ring the substantial cross section extension of the blowing tubular sheeting takes place.

Under the designation MULTICOOL® D/OPTIFIL® - P3 is offered to Windmöller & Höl kg a cooling ring system for the blowing foil production by the manufacturer, with which above the blowing head nozzle two cooling rings with axial distance are to each other arranged. The first cooling ring located directly on the Blaskopf is provided with a majority of heating elements, which sektorweise can be steered separately. Similarly as with a long neck driving fashion the substantial cross section enlargement of the blowing tubular sheeting takes place above the second upper cooling ring, which yields an unsettled cooling gas flow homogeneous over the extent. The length of the hose education formation from the nozzle exit to the freezing border at the calibration basket becomes larger thereby substantially whereby within the flaschenhalsförmigen range between first cooling ring and second cooling ring only a small material drawing takes place.

The available invention is the basis the task to make a procedure and a device available of the kind initially specified with which improved results are causable concerning the extent thickness range of the Schlauchfolie. The solution for this exists in a procedure for the regulation of the thickness profile of a Schlauchfolie of thermoplastic plastic over their extent with the production of Schlauchfolien by means of a blowing foil extrusion with a deflector, whereby by means of measuring instrument the foil thickness of the Schlauchfolie over the extent and variable steered by means of a controlling mean cooling gas flows as a function of the measured foil thicknesses over the extent sektorweise are measured, whereby the cooling gas flows are supplied from the outside in production direction in two levels from each other beabstandeten and the cooling gas flows in the two levels in their physical characteristics over the extent sektorweise variable are in each case steered.

Invention covers accordingly further device to regulation thickness profile Schlauchfolie from thermoplastic plastic with production of Schlauchfolien to arrangement to blowing foil extrusion with deflector, comprehensively measuring instrument to measurement thickness profile Schlauchfolie, which foil thickness Schlauchfolie over extent measures, and controlling mean, which cooling gas flows as a function of the measured foil thicknesses over the extent sektorweise variable steered, as well as two cooling rings, which are to be arranged over the deflector of blowing foil extrusion in two levels from each other beabstandeten, whereby the two cooling rings exhibit means, with which the cooling gas flows sektorweise it are variable controllable.

The solution according to invention is characterised in the effect by that by way of the extent sektorweise variable controllable cooling gas flows can be supplied by way of a substantial length of the production process by the withdrawal of the Schlauchfolie from the nozzle blowing head on to close before the entering of the Schlauchfolie a calibration basket, without the effect of the cooling gas flows is lost by mixing or heating after short distance in production direction. The yield speed of the Schlauchfolie can be increased by the effective range of the cooling gas supply variable substantially stretched in production direction adjustable over the extent clearly, so that with at least continuous quality a production increase becomes possible.

Here it is of advantage special that the sektorweise variable change of the cooling gas flows straight still takes place also, where via the concluding strong cross section extension of the tubular sheeting a clear transverse drawing of the material takes place, so that the individually different cooling over the extent can affect itself clearly in a thickness distribution correction. This is given also with the simple cooling ring with auxiliary cooling ring after the DE 100 29 175 A1, with which however the axial effective range is very short, so that the cooling can become insufficient with high output achievements. On the other hand the further designated double cooling ring does not fulfill this criterion, since with this before the substantial cross section enlargement of the tubular sheeting at the second cooling ring evenly strongly over the extent one cools, so that still existing thickness profile errors are almost frozen and existing to remain.

The change of the physical controlling of the cooling gas flows includes the possibility of varying the flow rates just like the temperature of the cooling gas. An independent control in the two levels, which is possible in preferential execution, opens the possibility of pursuing different rule patterns in order to realise for example in a first level the influencing control according to a rough pattern and in a second level the influencing control according to a fine pattern. The regulation of the thickness profile will usually take place on constant thickness of the Schlauchfolie. It is however also possible to stop and regularly maintain certain thickness distribution structures. The cooling air distribution over the extent can be steered at both cooling rings and/or in both outlet planes agreeing, or after an agreeing control pattern, angleshifts however against each other or in the two cooling ring levels completely differently, however one on the other co-ordinated to take place. A thickness profile measurement finds preferentially only in one level behind the second cooling ring instead of.

The passage of the cooling rings can be adapted to the diameter development of the tubular sheeting. Here preferentially in each case the down-lying entrance diameter for the tubular sheeting is smaller than the obenliegende effective diameter for the tubular sheeting at the cooling rings. Further prefers an interior cone, which contains these two axially beabstandeten diameters, at the lower cooling ring, defined by entrance diameters and effective diameters of the cooling ring as well as their axial distance, has a smaller opening angle than at the upper cooling ring. With this interior geometry of the cooling rings an appropriate progressive rate of several ring sensors or nozzle lips a cooling ring accompanies in each case within the appropriate interior cone, whose diameter differences are smaller at the lower cooling ring therefore than at the upper cooling ring.

The diameter of the two cooling gas supply and/or cooling rings can be adapted to a diameter change of the Schlauchfolie in this production phase in the way that the lower cooling ring has a smaller inside diameter, as the upper cooling ring. The relationship of the entrance diameters from upper cooling ring to lower cooling ring is preferentially more largely larger as 1.1, in particular than 1,2. Each of the two cooling rings can cover two component currents, of which a first smaller component current over the extent sektorweise is homogeneous controllable and a second larger component current over the extent in preferential way. The latter larger component current can withdraw in two lying on top of each other ring sensors, in particular behind the first component current.

In preferential addition sektorweise controllable cooling air knows a likewise controllable keeping at a moderate temperature of the foil material in the Blaskopf in addition-steps, is it by heating or by cooling to, whereby the controlling of the cooling air flow of both cooling rings and the controlling of keeping at a moderate temperature can be summarized if necessary in a common automatic control loop.

In preferential way an influence of the Schlauchfolie variable over the extent can from the inside in addition-steps for the regulation of the thickness profile by the external cooling rings mentioned, whereby an internal cooling gas flow can likewise be controllable sektorweise over the extent. Here an agreeing common control can be used on the inside and on the exterior. Also the sectoral interior cooling can distribute itself on two levels in production direction, which prefers the levels of the outside cooling rings is assigned.

By an axial spacer controllability of the cooling gas flows and/or cooling rings a special adjustment is possible to different production speeds. In all other respects this facilitates a starting of production, as an accesibility can be manufactured to the foil nozzle of the Blaskopfes.

Preferential remark examples of devices according to invention are represented and are described in the following in the designs.

Show

Figure 1

a foil blowing plant with two cooling rings, which in each case exhibit a controllable partial cooling ring with rule elements for a sektorweise independent influence of the cooling gas flows and a uncontrolled partial cooling ring;

Figure 2

a foil blowing plant after figure 1 with an additional sektorweise controllable keeping at a moderate temperature of the deflector;

Figure 3

a foil blowing plant with two cooling rings, which have in each case a uniform cooling ring with control members for a sektorweise independent influence of the cooling gas flows;

Figure 4

a foil blowing plant after figure 3 with an additional sektorweise controllable keeping at a moderate temperature of the deflector;

Figure 5

a foil blowing plant with two cooling rings, which have in each case a uniform cooling ring with control members for a sektorweise independent keeping at a moderate temperature of the cooling gas flows;

Figure 6

a foil blowing plant after figure 5 with an additional sektorweise controllable keeping at a moderate temperature of the deflector;

Figure 7

a foil blowing plant with two cooling rings, from which first exhibits a controllable partial cooling ring with control members for a sektorweise independent influence of the cooling gas flows and a uncontrolled partial cooling ring, and which second a uniform cooling ring with control members for a sektorweise independent influence of the cooling gas flows has;

Figure 8

a foil blowing plant with two cooling rings, which in each case cover a controllable partial cooling ring with control members for a sektorweise independent influence of the cooling gas flows and a uncontrolled partial cooling ring, as well as with an additional interior cooling ring for a sektorweise independent influence of the cooling gas flows;

Figure 9

the deflector, the lower controllable partial cooling ring and the above lower uncontrolled partial cooling ring with appropriate cooling gas supply after the figures 1, 2 and 7 in increased partial section;

Figure 10

the nozzle exits at the lower controllable cooling ring after figure 9 as increased detail;

Figure 11

a disk element of the lower controllable cooling ring after figure 9 in plan view;

Figure 12

the Blaskopf with the lower controllable partial cooling ring, the lower uncontrolled partial cooling ring and the interior cooling ring after figure 8 in increased partial section;

Figure 13

the exhaust nozzles of the lower controllable cooling ring and the interior cooling ring after figure 12 as increased detail;

Figure 14

a disk element of the interior cooling ring after figure 12 in plan view.

The device shown in figure 1 covers a blowing foil extrusion 10 with a Blaskopf 11, a first cooling ring 12 with a ring channel 13 for a constant homogeneously withdrawing partial cooling gas flow and one below the same arranged segment disk 14 for a sektorweise controllable partial cooling gas flow as well as an above second cooling ring 12 ' with a ring channel 13 ' for a constant homogeneously withdrawing partial cooling gas flow and one below the same arranged segment disk 14 ' for a sektorförmig controllable partial cooling gas flow. Both cooling rings 12, 12 ' serve 16 at the Blaskopf of 11 withdrawing tubular sheeting 17 for the cooling from a ring sensor. For the regulation of the thickness profile of the tubular sheeting 17 measuring instrument 31 is intended, which scans the foil thickness at the tubular sheeting 17 above a freezing border, and a controlling mean 34 over the extent, which varies the cooling gas flows as a function of the foil thicknesses sektorweise measured over the extent.

The segment disks 14, 14 ' are arranged underneath the ring channels 13, 13 ' in each case, in order to exert the greatest possible influence on the reduction of the foil thickness tolerances thereby that the hotter in each case materials areas of the tubular sheeting on the entrance side are controllable cooled into a cooling ring sektorweise. The segment disks 14, 14 ' are in each case with a blower 18, 18 ' covered for the sektorweise controllable partial cooling gas flows connected, whereby for the allocation by the blower 18, 18 of ' produced cooling gas flow into individual separate part cooling gas flows a control unit 19, 19 ' is intended in each case, the one majority by separately controllable flaps and/or valves. The cooling rings 12, 12 ' are relatively to each other axially adjustable with adjustment means 15, whereby the lower cooling ring 12 preferably directly to the Blaskopf 11 is fastened.

The control devices 19, 19 ', which are headed for by the controlling mean 34, permit in each case a very exact regulation of the thickness profile with the production of Blasfolien due to the cooling gas supply sektorförmig controllable over a wide axial range.

The controllable partial cooling gas flows are supplied in each case in production direction of the tubular sheeting 17 before the homogeneous partial cooling gas flows and directed directly against the tubular sheeting 17 withdrawing from the Blaskopf 11. The controllable partial cooling gas flows before the entering the segment disks 14, 14 ' by the control devices 19, 19 ' are varied separately in their flow rate.

The Blaskopf 11 covers a ring sensor 16, which withdraws above with vertical axle center A from the Blaskopf. From the ring sensor 16 the tubular sheeting 17 withdraws, which is expand and stabilized by means of an internal pressure production device 20 and with a trigger mechanism 30 is upward taken off. Here it is supported by one above the cooling rings 12, 12 ' lying calibration basket 22 and essentially defined in its final diameter. The tubular sheeting 17 circularly enclosed of the two cooling rings 12, 12 ' with the ring channels 13, 13 ', from which in each case an essentially circularly homogeneous partial cooling gas flow escapes, as well as directly under it lying segment disks 14, 14 ', from which sektorweise controllable partial cooling gas flows escape. The cooling gas flows affect on the one hand stabilizing the tubular sheeting 17 in extension, on the other hand cooling themselves them the plastic foil material withdrawing from the ring sensor 16, until in a circulating freezing zone the plastic extension of the tube material is terminated due to the cooling. The cooling rings 12, 12 ' consist essentially in each case of a torus-shaped ring channel 13, 13 ', that some extent-distributed feed parts 23, 23 ' and at least in each case a ring sensor 24, 24 ' exhibit in each case, made of which the circularly homogeneous partial cooling gas flow withdraws as evenly as possible.

The segment disks 14, 14 ' consist in each case of a einstückigen Ringsegmentkörper, which exhibits a majority of supply connecting pieces 25, 25 ' and the inside which is obvious at its tubular sheeting 17 in each case individual exhaust nozzles ' has 26, 26, of which individual sektorweise controllable partial cooling gas flows withdraw. While the supply lines are not represented to the connecting pieces 23, 23 ' of the ring channels 13, 13 ', exemplarily individual directions 27, 27 ' represented to the supply connecting pieces 25, 25 ' of the segment disks 14, 14 are '. These lines are connected with one of the control devices 19, 19 ' in each case, which one number of the of extent-distributed lines 27, 27 ' appropriate number of control valves 29, 29 ' enclosure, by which four in each case are on behalf represented, all this of one of the blowers 18, 18 ' over in each case a supply line 28, 28 ' are compressed air-subjected to the actual. Above the calibration basket 22 is a contactless thickness measure 31, which is coaxially to the hose arranged ball race 32 fastened on one and which can make a thickness distribution measurement over the extent by periodic Umfahren of the tubular sheeting 17. Between the individual measurements of the extent thickness distribution the measuring instrument 31 can be kept stationary and be made a longitudinal thickness process measurement of the tubular sheeting along a Mantellinie, whereby this longitudinal thickness process is representative for the longitudinal thickness change of the entire tubular sheeting. As symbolizes 33 by a signal line, the result of the thickness measurement is converted in a regulation unit 34, from that a control line 35, 35 ' to the blowers 18, 18 ' and a control line 36, 36 ' to the control devices 19, 19 ' to go in each case in each case. With the control lines 35, 35 ' the fan speed can be varied altogether; over the control lines 36, 36 ', those representatively of a multiplicity from control lines to the individual control valves 29, 29 ', the cross-section of the opening of the usually pulse-far-modulated control valves 29, 29 stands ' can be steered separately. The measurement of the extent thickness distribution converted into a controlling of the individual sektorweise adjustable partial cooling air flows, whereby the thickness profile is regulated on lowest possible deviations. The measurement of the longitudinal thickness process serves the period of the change of longitudinal thickness for the statement. This can be as a whole likewise regulated by change of the cooling gas flows on lowest possible deviations.

In figure 2 a majority of extent-distributed heating cartridges 65 or cooling sections (e.g. Peltier elements) is intended in addition of the details by figure 1 in the Blaskopf 11, which can be steered over control lines 66 independently of the rule unit 34 likewise sektorweise. Hereby an additional variable keeping at a moderate temperature of the tubular sheeting 17 before the withdrawal from the ring sensor 16 takes place.

In figure 3 the cooling rings 12, 12 do not cover ' deviating from figure 1 segment disks, but excluding uniform ring channels 13, 13 '. In these extent-distributed control members 67, 67 ' (e.g. flaps) arranged with Stellgliedem 68, 68 ' are, which can vary the flow rate independently to individual extent extent. The position units 68, 68 ' are connected by control lines 69, 69 ' likewise with the central rule unit 34.

In figure 4 a majority of extent-distributed heating cartridges 65 or cooling sections (e.g. Peltier elements) is intended in addition of the details by figure 1 in the Blaskopf 11, which can be steered over control lines 66 independently of the rule unit 34 likewise sektorweise. Hereby an additional variable keeping at a moderate temperature of the tubular sheeting 17 before the withdrawal from the ring sensor 16 takes place.

In figure 5 the cooling rings 12, 12 do not cover ' deviating from figure 1 segment disks, but excluding uniform ring channels 13, 13 '. In these extent-distributed heating cartridges 71, 71 ' or cooling sections (e.g. Peltier elements) are arranged, which can keep at a moderate temperature the flow rate independently to individual extent extent. The heating cartridges 71, 71 ' are connected by control lines 72, 72 ' likewise with the central rule unit 34.

In figure 6 a majority of extent-distributed heating cartridges 65 or cooling sections (e.g. Peltier elements) is intended in addition of the details by figure 6 in the Blaskopf 11, which can be steered over control lines 66 independently of the rule unit 34 likewise sektorweise. Hereby an additional variable keeping at a moderate temperature of the tubular sheeting 17 takes place.

In figure 7 the lower cooling ring 12 and its control is implemented according to kind of the cooling ring represented in figure 1, while the upper cooling ring 12 is implemented ' with its control according to kind of the cooling ring 12 ' represented in figure 3. Same details are occupied with same reference numbers.

Also here 11 extent-distributed heating cartridges 65 or cooling sections (e.g. Peltier elements) are intended in the deflector, which are controllable sektorweise over additional control lines 66 over the extent.

In figure 8 a device is shown in a supplemental execution in agreeing large representation with figure 1, with which the same details as in are occupied figure 1 with the same Bezugsziffem. To the description given in addition is referred to that extent. Within the tubular sheeting 17 additionally an interior cooling device 47, which is screwed onto the Blaskopf 11 and several elements covered, is on which below still more near purchase is taken. At the extent of the device 47 ring sensors 49, 50 in different levels, which withdraw radially outward, are. These are supplied via an interior cavity 51 with cooling gas, which is again sucked off over a coaxial central discharge duct 52 with open above end. Between interior cooling device 47 and Blaskopf 11 a further auxiliary cooling ring 48 is assigned, produced for the one majority by internal auxiliary cooling gas flows 53 over single nozzles 54, which are supplied via individual supply lines 55 with sektorweise controllable cooling gas. The lines 55 can be branch lines of individual directions 27 in each case, so that with uniformly steered additional cooling gas from the inside and outside sektorweise determined extent ranges of the tubular sheeting 17 controllable is in each case subjected.

In figure 9 the ring sensor 16 and the lower cooling ring 12 are shown in increased partial sections. Same details are occupied with same Bezugsziffem, whereby here different characteristics are constructionally implemented. One the feed part 23 follows a supply line 37. It is covered clearly that the lower cooling ring 12 as ring channel 13 is designed, beside a first nozzle exit ring 24 a further nozzle exit ring 38. The ring channel 13 exhibits surface 39 to a lower flat at least in its internal area, against which the segment disk 14, which has an upper flat in principle surface 41, is bolted. In the segment disk 14 individual radial slots 42 are implemented, which are connected radially outside by throughholes 43 with the individual pipe unions 25, while they end radially inside in the Zusatzdüsen 26. The Radiainuten 42 forms the individual cooling gas channels with the flat surface 39. The segment disk 14 is centered over centring clamps 44 opposite the Blaskopf 11. Thus in the same way also the ring channel 13 bolted with the segment disk 14 is centered opposite the Blaskopf and the ring sensor 16. In the range of the single nozzles 26 an insulating washer 40 between Blaskopf 11 lies and segment disk 14. The structure here of the not represented upper cooling ring is completely homogenous with exception of the diameter.

In figure 10 is recognizable as increased detail design in the same representation as in figure 9 the Blaskopf 11 with the ring sensor 16, from which the tubular sheeting 17 withdraws, which is represented with even wall thickness simplifying here. On the Blaskopf 11 the insulating washer 40 is visible, over it lies the ring channel 13 with the ring sensors 24, 38 and the segment disk 14 with single nozzles 26 screwed under it.

In figure 11 the segment disk 14 shown after figure 9 is as detail in plan view. In an essentially flat flange surface 41 the radial slots 42 already addressed are recognizable, which end outside with distance from the extent edge and with the throughholes 43 connection have and which inward in from each other the nozzle bores 26 separate by transition pieces 45 to end. In the center is the central depressing opening 46 for the tubular sheeting.

In figure 12 the Blaskopf 11, which is shown lower cooling ring 12 with ring channel 13 and segment disk 14 in the same way in figure 9, with same reference numbers occupied same details, is to the description of the figure 9 reference is taken to that extent. In addition the interior cooling device 47 put on on the Blaskopf 11 is recognizable inside the tubular sheeting 17, whose lowest element is the internal auxiliary cooling ring 48, which is unscrewed on a cylinder barrel 56 within the Blaskopfes 11. Within this pipe 56 the supply lines 55 are implemented as drillings. The auxiliary cooling ring 54 covers through-holes 57 58 radial slots 59 implemented for connection with these Zuführungsleitungen 55 as well as in a flat surface, whose ends form the single nozzles 54. The interior cooling device 47 covers further several disk elements set one on the other, from which a lower flat lower surface exhibits 60, which shoots the radial slots 59 upward, so that individual cooling gas channels are formed. The individual disk elements form the ring sensors 49, 50 and are interconnected with one another by lattice cases. Between the segment disk and the Blaskopf 11 a further insulating ferrule 62 is intended.

In figure 13 already the details recognizable in figure 12 are increased shown, whereby in particular the formation of the auxiliary cooling gas releases becomes clear 54 the lower of the ring elements of the interior cooling device 47 as well as the connection of the through-holes 57 with the supply channels 55 by the auxiliary cooling ring 48 and.

In figure 14 the internal auxiliary cooling ring 48 shown with the details specified already through-holes 57 and radial slots 59 is, which are in-milled in a flat surface 58. These radial slots 59 are at least separate to close to the outer circumference by separation bars 63 from each other. The bull's eye/target 48 has a central opening 64 for the general cooling gas supply.

10

Blowing foil extrusion

11

Blaskopf

12

Cooling ring

13

Ring channel

14

Segment disk

15

Adjustment means

16

Ring sensor

17

Tubular sheeting

18

Blower

19

Mechanism to the valve gear

20

21

Internal pressure device

22

Potash beer basket

23

Supply connecting piece

24

Ring sensor

25

Supply connecting piece

26

Single nozzle

27

Auxiliary cooling gas line

28

Supply line

29

Control valve

30

Trigger mechanism

31

Measuring instrument

32

Ball race

33

Signal line

34

Rule unit

35

Control line

36

Control line

37

Supply line

38

Ring sensor

39

Flat surface

40

Insulating washer

41

Flat surface

42

Radial channel

43

Throughhole

44

Centring chamber

45

Transition piece

46

Central opening

47

Interior cooling device

48

Auxiliary cooling ring

49

Ring sensor

50

Ring sensor

51

Supply area

52

Discharge duct

53

Auxiliary cooling gas flow

54

Single nozzle

55

Supply line

56

Cylinder barrel

57

Through-hole

58

Flat surface

59

Radial channel

60

Flat surface

61

62

Insulating washer

63

Separation bar

64

Central opening

65

Heating cartridge

66

Control line

67

Control member

68

Control member

69

Control line

70

71

Heating cartridge

72

Control line