WO2001012413A1

WO2001012413A1 - Device and method for producing corrugated pipes made of plastic

Info

Publication number: WO2001012413A1
Application number: PCT/DE2000/002803
Authority: WO
Inventors: Mile Voll-Marjanovic
Original assignee: Unicor Gmbh Rahn Plastmaschinen
Priority date: 1999-08-18
Filing date: 2000-08-16
Publication date: 2001-02-22
Also published as: CA2391815A1; EP1204522A1; JP2003507207A

Abstract

The invention relates to a device for producing corrugated pipes made of plastic. Said pipes have nominal diameters of less than 10 mm. The device consists of an extrusion device (2), a vertically oriented extrusion die (7) and a vertically oriented corrugator (8) with a vertical die cavity (35). The extrusion die (7) is provided with a nozzle that is configured in a relatively short manner in the axial direction thereof and has an annular gap (70). The extrusion die is arranged in such a way that the annular gap (70) is arranged outside the die cavity (35) and is spaced apart from the upper inflow side of the front end pertaining to the die cavity (35).

Description

Device and method for producing corrugated plastic pipes

The invention relates to a device for producing plastic tubes, preferably plastic corrugated tubes, in particular with a nominal diameter of <10 mm, with at least one extrusion device, with at least one spray head connected downstream in the production direction and vertically oriented in the operating position, which has at least one annular gap, and with a downstream of the spray head in the production direction, vertically directed in the operating position, by moving mold jaws, e.g. Corrugator jaws formed mold cavity for shaping the plastic corrugated tube from at least one plastic melt jet emerging from the annular gap of the spray head.

The invention further relates to a method for producing plastic pipes, preferably plastic corrugated pipes, in particular with a nominal width of <10 mm, wherein a plastic mass, by means of an extrusion device from an annular gap of one of the extrusion devices downstream, which is directed vertically in the operating position, as a plastic melt. Beam into a through moving mold jaws, e.g. Corrugator jaws formed mold cavity is passed, in which the plastic melt jet is brought into shape by external negative pressure and / or by internal excess pressure.

Such a device with a method is known from DE 197 24 857 A1, but for the production of corrugated pipes with a large outside diameter of the order of 1 to 2 m. The also vertically directed molding section is formed by corrugator jaws, which are adjusted in pilgrim steps by means of appropriately driven swivel arms. The one also directed vertically

Spray head protrudes relatively far into the molding section. It is combined with a calibration mandrel that extends through the molding section to the downstream end known, has compressed air channels for internal exposure to compressed air and cooling channels for liquid cooling. Relatively complex adjustment work is required to carry out the method, since the spray head with its downwardly projecting nozzle and calibration device must be precisely aligned in the molding section formed by the corrugator jaws. This device with a vertical corrugator is not suitable for the production of corrugated pipes of small nominal size, since with this vertical arrangement the adjustment and calibration work for shaped sections of small diameter would be practically impossible.

In practice, devices with horizontally directed corrugators are usually used to produce corrugated plastic pipes of small nominal size. Such a device with method is e.g. known from DE 36 22 775 A1. A corrugator is used there, the corrugator jaws of which are moved along two endless tracks. The mold cavity formed by the corrugator jaws lies horizontally, the spray head nozzle engaging far into the mold cavity. In practice, therefore, very long, thin nozzles are required for the production of pipes of small nominal size in order to ensure that a uniform pipe wall is obtained. A disadvantage of the production, in addition to the adjustment problems, is the high back pressure resulting from the long, thin nozzles, with the result that the output is severely limited. There are also complicated cleaning processes and problems with the start-up process after freezing the material, e.g. due to cooling of the long nozzle. There is also the risk of damage to the nozzle device and the mold jaw profile due to misalignment during production. The problems are exacerbated the smaller the nominal widths of the corrugated pipes. On the one hand, the production and operational safety of the required very thin nozzles reach the limits of technical feasibility, on the other hand, the pressures during extrusion cannot be reduced arbitrarily.

DE-AS 1 504 701 discloses a differently constructed device for producing plastic pipes. It uses a stationary calibration device with a downstream trigger device. The mold cavity is in the stationary calibration device is designed as a rigid hollow body. The device can only be used to produce pipes with a constant cross-section over their length, ie not corrugated pipes. The extraction device T connected downstream of the calibration device pulls the tubular tube emerging from the annular gap of the nozzle through the mold cavity of the calibration device. Therefore, it is possible to work with a nozzle that does not immerse in the mold cavity, and the same nozzle with a circular annular gap can be used universally in connection with different calibration devices with different cross-sectional shapes of the mold cavity, provided that the interior of the mold is made of the annular gap emerging, which is still plastically deformable, is not subjected to internal pressure. When subjected to internal pressure, the tube emerging from the annular gap could inflate before entering the mold cavity and collide with the inlet opening of the calibration device and jam there. The device known from DE-AS 1 504 701 therefore requires a reliably operating, separate extraction device connected downstream of the mold cavity and does not allow the tube to be subjected to internal pressure.

The invention has for its object to provide a device and a method for producing corrugated plastic pipes in order to enable the production of corrugated plastic pipes, in particular of small nominal size, with little outlay on equipment and simple, practical implementation.

This object is achieved according to the device with the subject matter of claim 1 and according to the method with the subject matter of claim 16.

The solution provides that the annular gap of the nozzle device of the spray head is arranged outside the mold cavity, in that the annular gap is arranged at a distance or immediately adjacent to an upstream end of the mold cavity formed by the corrugator jaws. This means that the spray head does not have to engage in the mold cavity with its annular gap. The spray head or its nozzle device can thus be made relatively short axially become. Due to the vertical alignment of the spray head - unlike in the case of conventional horizontal alignment of the spray head and corrugator - there is no undesirable influence of gravity with the risk of uneven wall thickness. It is also possible to work with a lower external vacuum or internal pressure. The use of the shorter nozzle and its arrangement outside the mold cavity not only results in advantages for the adjustment and adjustment work, but also high operational reliability and a significant increase in output can be achieved. Due to the lower pressure drop in these shorter nozzles, it is possible to work at a very high production speed. This enables a significant increase in output, possibly up to the cooling capacity limit of the corrugator.

The method can be carried out in such a way that the diameter of the emerging plastic melt jet, preferably its inner diameter and / or its outer diameter, is determined and / or controlled by adjusting the distance from the annular gap to the upstream end of the mold cavity. The distance between the annular gap and the upstream end of the mold cavity represents a production parameter which is dependent on the diameter of the plastic pipe to be produced and on the plastic material used.

The method can also be carried out in such a way that the diameter of the emerging plastic melt jet, preferably its inner diameter and / or its outer diameter, is determined by adjusting the ratio of the flow velocity of the plastic melt jet as it emerges from the annular gap relative to the production speed of the corrugator and / or is controlled. If the production speed of the corrugator is set to be greater than the exit speed of the molten plastic jet at the annular gap, depending on the set distance between the annular gap and the upstream end of the mold cavity, the elastic plastic melt jet emerging from the annular gap can be achieved until it enters is deliberately narrowed into the mold cavity. A particularly strong reduction in the undesirable pressure drop in the nozzle and thus a particularly strong increase in output becomes possible if it is provided that the outside diameter of the annular gap is greater than or equal to that of the nominal diameter of the plastic pipe to be produced, preferably the effective inside diameter and / or the outside diameter of the plastic pipe to be produced. The effective inside diameter for corrugated pipes is the inside free diameter in the area of the narrowing of the corrugation or for double or multi-wall pipes the inside diameter of the inner pipe. In the production of pipes which can be designed with or without corrugation, but which have constrictions or extensions at one or more points over the distance of the mold cavity, it can be provided that the outer diameter of the annular gap is greater than or equal to the minimum inner diameter and / or maximum inside diameter and / or the minimum outside diameter and / or the maximum outside diameter of the plastic pipe to be produced.

Based on the dimensions of the mold cavity or the corrugator, it can be provided that the outer diameter of the annular gap is greater than or equal to the minimum inner diameter and / or the maximum inner diameter of the mold cavity.

In contrast to the invention, with known conventional operation and arrangement, the outer diameter of the nozzle must always be smaller than the diameter of the tube to be produced, since the nozzle immerses in the mold cavity and must lie within the inner diameter of the tube to be produced. In contrast, the invention allows the use of nozzles with a larger outer diameter for the production of pipes of the same or smaller nominal widths. This advantage is particularly evident when pipes with nominal diameters of less than or equal to 6 mm inside diameter are manufactured. With the arrangement of the annular gap outside the mold cavity, it is also possible to manufacture pipes that have special shapes. For example, pipes with special cross-sectional geometries can be manufactured. Pipes can be made which, in contrast to the conventional circular cross-sectional shape, have square, rectangular, triangular or triangular or oval cross-sectional shapes. In these cases it is provided that the mold cavity has a corresponding shape in cross section. The nozzle or the annular gap respectively arranged outside the mold cavity can each have a conventionally round cross section. This means that the tubes with these special cross-sections can be manufactured with conventionally constructed nozzles.

With the arrangement of the annular gap outside the mold cavity it is also possible to produce pipes which have a varying cross section at one or more points over the distance of the mold cavity, regardless of the presence of a corrugation, e.g. have constrictions or enlargements at certain points or at least sectionally conical. The outer diameter of the annular gap or the nozzle then does not have to be chosen smaller than the diameter of the narrowest cross-sectional point due to the arrangement outside the mold cavity. The same applies to the production of pipes with a section that is laterally offset, oblique or curved with respect to the axis of the spray head or the axis of the annular gap. Such special shapes can also be manufactured using conventional nozzles by arranging the annular gap outside the mold cavity. It can be provided here that only the mold cavity has a complementary shape corresponding to the special shape of the pipe to be produced.

For the production of pipes of conventional cross-sectional shape

Formation of the mold cavity Corrugators of conventional construction can be used. They are preferably only slightly modified. Corrugators can be used for the production of tubes with a special shape, which have a correspondingly modified shape of the mold cavity. In all versions, however, it is essential that the corrugator is arranged in the operating position in such a way that the molding section is aligned vertically with the mold cavity. Corrugators that migrate can be used Have corrugator jaws which are moved in pilgrim steps, for example by means of appropriately driven swivel arms, or which are driven in the manner of an endless belt. The spray head is used vertically downwards, in particular so that the annular gap is arranged between the upper edge of the path of movement of the mold jaws and the upstream end of the mold cavity formed by the mold jaws or above the upper edge of the path of movement of the mold jaws. When using a spray head that has a tubular downstream end, it can be provided that this tubular end engages axially in the mold cavity over a length that is considerably shorter, for example, more than half shorter than the axial extension of the spray head or than that axial extension of an axially extending channel with an annular cross section in the spray head, which leads to the annular gap.

In order to achieve an adjustability of the position of the mold cavity or the corrugator relative to the spray head, it is preferably provided that the position of the mold cavity or the corrugator is adjustable in the vertical and / or horizontal direction, preferably with the spray head in an unchanged position.

A particular advantage results from the vertical adjustment of the position of the mold cavity in relation to the injection head, since this enables a targeted expansion and consequent contraction of the extrudate, depending on the melt strength of the elastic plastic, so that extrudate is not pinched between the mold jaws.

Particular advantages result if the mold cavity or the corrugator can be pivoted about a horizontal axis. The corrugator can thus be swiveled from its vertical operating position into a horizontal rest or maintenance position. In this horizontal position, the mold jaws can be easily adjusted or replaced. Furthermore, cleaning and

Setup work on the mold jaws and on the entire rest of the corrugator can be carried out in this position. In special designs it is provided that the spray head and / or the extruder, preferably the extruder together with the spray head, is adjustable relative to the corrugator in the operating position. There are particular advantages, for example for start-up operation, if the extruder is preferably pivotable about a vertical axis or if the extruder is displaceable. In the start-up mode it can be provided that the extruder together with the spray head is placed in a side position in which the spray head is not directed into the mold cavity, but is laterally offset from the corrugator and the plastic melt jet is therefore not introduced into the corrugator.

In order to ensure high manufacturing quality, a pressure generating device can be assigned to the mold cavity for generating negative pressure and / or excess pressure, with the aid of which the plastic mass of the plastic melt jet entering the mold cavity can be brought into contact with the inner wall of the mold cavity.

In preferred embodiments of the spray head it is provided that the spray head has an inner member, for example a support air tube, mandrel and / or cooling mandrel, which is supported on the spray head and extends to the downstream end of the spray head and forms the annular gap with the inner wall of the spray head. Provision can be made here for the inner member to extend parallel to the inner wall of the nozzle on the outflow side, with the formation of an outlet channel which is annular in cross section. It can be provided that the downstream end of the inner member ends in the area of the annular gap or protrudes from the annular gap. With regard to the arrangement of such a spray head relative to the mold cavity, it can be provided that the end of the inner member projecting from the annular gap protrudes more or less into the mold cavity or ends directly at the upstream end of the mold cavity or does not protrude into the mold cavity and at a distance from it upstream end of the mold cavity ends, wherein the annular gap can preferably be arranged outside the mold cavity. With all of these Arrangements make it possible to carry out the adjustment and setting work in a practical manner, and good handling when carrying out the operation with sufficient operational safety, and good production quality can be achieved with a correspondingly high output.

Further details, features and advantages result from the following description of an exemplary embodiment of the device according to the invention, shown schematically in the drawing, for carrying out the method according to the invention for producing corrugated plastic pipes. Show it:

Figure 1 is a schematic front view of an embodiment of the device for

Manufacture of corrugated plastic pipes,

FIG. 2 shows a side view along arrow II in FIG. 1,

FIG. 3 shows a top view from above along arrow III in FIG. 1,

4 shows a sectional view of a detail in the region of the spray head along section line IV-IV in FIG. 3 or one parallel to the image plane in FIG

FIG. 1, sectional plane A,

Figure 5 is an enlarged view in Figure 4 in the area of the outflow

End of the spray head and the adjoining upstream upper region of the corrugator,

6 shows a plan view corresponding to FIG. 3, but in the inoperative position with an extrusion device pivoted about a vertical axis together with the spray head, Figure 7 is a side view corresponding to Figure 2, but in

Decommissioned position with corrugator pivoted about a horizontal axis.

The device for producing corrugated plastic pipes is shown in FIGS. 1, 2 and 3 in different perspectives in the operating position. The device 1 has an extrusion device 2, which is arranged on an upper level of a support frame 3. The extrusion device 2 has an extruder 4, which is arranged horizontally in its axial extent on the above-mentioned upper level of the support frame 3. In a modified version, the extruder can also be arranged vertically.

The extruder 4 has a funnel-like bulk material receptacle 5 on the inlet side and an outlet nozzle 6 on the outlet side. A spray head 7 is connected to the outlet nozzle 6. The spray head 7 lies outside the carrier frame and extends vertically downward. A likewise vertically directed corrugator 8 is then arranged on the spray head 7 below. The corrugator 8 is mounted on a carriage 10, which is movably supported on a vertical post 9 of the support frame 3. At the lower end of the corrugator 8, an outlet opening is formed, from which the finished plastic corrugated tube emerges. A deflection roller 11 is mounted on the lower level of the support frame 3, via which the plastic corrugated tube emerging from the outlet opening of the corrugator 8 is deflected and pulled off to the left in the illustration in FIG. 1. From there it can be wound onto a supply roll, not shown.

The corrugator 8 is mounted on the post 9 on the post 9 so that it can move vertically. The carriage 10 is motor-driven by means of a drive device 13 supported on the post 9. The drive direction 13 has a drive motor 14 which drives a vertically directed spindle 15 mounted on the post. The carriage for positioning and adjusting the corrugator 8 can be moved in the vertical direction via this motorized device. In addition, a pivoting device 16 is provided, with which the corrugator 8 can be pivoted about a horizontal axis 20. The pivot axis 20 is supported at one end on the slide 10 and at the other end in the housing of the corrugator 8. To actuate the swivel device 16, a hand lever 17 is provided which is connected to the swivel axis 20 and is guided in a curved guide 17a. The corrugator 8 can be pivoted into the inoperative position shown in FIG. In this position of the corrugator 8, maintenance and repair work can be carried out in a simple manner.

The corrugator 8 has, in a manner known per se, a vacuum device 18 with individually adjustable vacuum zones, with which a negative pressure is generated on the inner wall of a mold cavity 35 formed in the corrugator (see FIGS. 4 and 5) in order to engage the plastic material of the plastic melt stream to bring to the inner wall of the mold cavity. The energy supply takes place via an energy supply band 19 which is connected to the corrugator 8 at its lower end.

The corrugator 8 is constructed in a manner known per se. The mold cavity 35, which is circular in cross section, is arranged one above the other

Corrugator jaw pairs 36, 37 formed as in the. 4 and 5 can be seen. The jaws 36, 37 assigned to one another in pairs are designed in cross section as half-ring segments which enclose an inner cavity which represents the mold cavity 35. The jaws 36 and 37 are guided synchronously in two endless loops which run in a vertical plane. The loop arranged on the left in FIGS. 4 and 5, which is formed from the jaws 36, is guided clockwise and the right loop, which is formed from the jaws 37, is guided in the counterclockwise direction. The movement takes place via a motorized drive device 39. In the vertical section, in which the corrugator jaws 36, 37 face each other vertically and linearly, the paired jaws 36, 37 are each joined together so that they tightly enclose the mold cavity 35. The upstream upper end of the mold cavity 35 is formed by the upper radial inner edge of those jaws 36, 37, which are currently last in the assembled position. In Figures 4 and 5 this upper upstream end edge of the mold cavity is designated 40.

The spray head 7 shown in FIGS. 4 and 5 consists of an essentially cube-shaped or cuboid base body 71 and a nozzle device 72 connected to it. The base body 71 is penetrated by an arcuate feed channel 73 which is connected to a right-hand one in the illustration in the figures Front side of the body 71 opens and opens out on the lower front side of the body 71. The nozzle device 72 is connected to the downward outlet mouth of the feed channel 73. It consists of an upper nozzle body 74, in which a central channel 25 is formed, which is directed vertically downward and is aligned with the outlet mouth of the supply channel 73. Channel 75 tapers downwards. At the end of its exit, it has expanded somewhat. In this area, a nozzle body 76 composed of several parts is connected. In this assembled nozzle body 76, a channel 77 with an annular cross section is formed, into which the channel 75 opens. The channel 77 is formed between an inner body 78 which tapers conically downwards and an outer body 79 which also tapers and has an annular cross section. At the tapered lower end of the

Outer body 79 has a nozzle tip 80 screwed into it, into which the end of inner body 78 extends, with further narrowing of annular channel 77. At the lower outlet opening of the nozzle tip 80, an annular gap 70 is formed, which forms the outflow-side nozzle outlet. A central channel 81 is also formed within the assembled body 76, which runs centrally through the inner body 78 and opens outwards at the same height as the annular gap 70. In the central channel 81, support air is supplied via a radial connecting channel 82 with an external connecting piece 83.

A multi-part heating jacket 85 is attached to the outer wall of the composite body forming the nozzle device 72. It has an electrical connection 86. Several in a row in the direction of flow arranged positions of the nozzle device are used in corresponding bores in the assembled nozzle body thermal sensor 87 for temperature measurement. A differential pressure meter 88, which is inserted in a corresponding radial bore in the nozzle housing 74, engages in the central channel 75.

The nozzle device 72 has a relatively short axial length compared to the conventionally used nozzle devices. This is possible because the spray head with the nozzle device 72 is directed vertically downward and the corrugator 8 is correspondingly designed with an axially vertically directed mold cavity 35. The plastic melt jet which emerges from the annular gap 70 and is annular in cross section is brought into radial contact with the inner wall of the mold cavity by the negative pressure acting on the jet from the outside in the region of the inner wall of the mold cavity. Gravity acts evenly here. In contrast to this, in the conventional mode of operation with a horizontally directed nozzle and a horizontally arranged corrugator, gravity acts in the sense of an uneven deflection of the melt jet entering the corrugator.

The nozzle device 72 engages with its vertically downward, downstream, tapered end, at the free end of which the annular gap 70 is formed, in the upper region of the corrugator 8, specifically in a region in which the corrugator jaws 36, which are assigned to one another in pairs , 37 have not yet reached their joining position in which they form the mold cavity. As shown in FIGS. 4 and 5, the annular gap 70 is arranged at a distance from the upstream end face of the mold cavity 35, that is to say above the end boundary edge 40 of the mold cavity 35. As can be seen in FIGS. 4 and 5, the tapered, downstream section of the nozzle device 72 engages between the not yet closed mold jaws 36, 37. The annular gap 70 lies between the upper boundary edge 40 of the mold cavity and the upper edge 41 of the path of movement of the circumferentially guided mold jaws 36, 37. The nozzle end with the annular gap 70 does not therefore extend over one, as is customary in conventional work with corrugators certain minimum length axially into the mold cavity. In the conventional procedure, in which the corrugator is arranged horizontally in operation, nozzle devices are used which have a significantly longer, downstream, tapered nozzle end, at the end of which the annular gap is formed.

The extrusion device 2 together with the spray head 7 connected to the nozzle 6 can, as shown in FIG. 6, be pivoted about a vertical pivot axis 21. The pivot position of the extrusion device 2 shown in FIG. 6 can thus be adjusted, in which the spray head 7, which is still vertically directed, does not align axially with the corrugator 8, in contrast to the normal operating position. This position is e.g. set to start up the extrusion device. Only after completion of the start-up operation is the extrusion device pivoted into the normal operating position shown in FIG. 3 and fixed there for operation via a locking lever 22 (FIG. 1).

The device works in normal operation for producing the plastic corrugated pipes as follows:

The plastic material fed via the funnel-shaped feed device 5 is pressed in the extruder 4 while extruding in the direction of arrow 25 in FIG. 1 to the left through the nozzle 6 into the spray head 7. The spray head 7 has on the outflow side the nozzle device 72 with the annular gap 70, from which the plastic melt emerges as a jet of plastic melt with an annular cross section, directed essentially vertically downward. This annular plastic melt jet thus enters the vertically directed axial mold cavity 35 of the corrugator 8 formed by the corrugator jaws 36, 37. Due to the negative pressure prevailing on the inner wall of the mold cavity 35, the material of the incoming plastic melt stream is brought into contact with the inner wall of the mold cavity 35. Because the production speed of the corrugator 8, ie the speed of movement of the corrugator jaws 36, 37 downwards in the vertical direction, while they form the mold cavity, is greater than that Exit velocity of the plastic melt jet at the annular gap 70, a constriction is formed in the tubular extrudate towards the end of entry into the mold cavity 35. The finished corrugated plastic pipe exits via the outlet opening at the lower end of the corrugator 8 at the front. The finished corrugated plastic tube is then deflected over the deflection roller 11 and drawn off at the lower level of the support frame 3 into a storage station, not shown.

Claims

claims

1. Device for the production of plastic pipes, preferably corrugated plastic pipes, in particular with a nominal width <10 mm, with at least one extrusion device (2), with at least one extrusion device (2) connected downstream in the production direction, in the operating position vertically directed spray head (7), the has at least one annular gap (70), with a downstream of the spray head (7) in the production direction, vertically oriented in the operating position by moving mold jaws (36, 37), for example Corrugator mold jaws (36, 37), formed mold cavity (35) for shaping the plastic tube from at least one plastic melt jet emerging from the annular gap (70) of the spray head (7), characterized in that the annular gap (70) outside the mold cavity (35) is arranged in that the annular gap (70) is arranged at a distance or immediately adjacent to an upstream end (40) of the mold cavity (35).

2. Device according to claim 1, characterized in that the outer diameter of the annular gap (70) is greater than or equal to the nominal width of the plastic pipe to be produced, preferably the effective inner diameter and / or the outer diameter of the plastic pipe to be produced.

Device according to one of the preceding claims, characterized in that that the outer diameter of the annular gap (70) is greater than or equal to the minimum inner diameter and / or the maximum inner diameter and / or the minimum outer diameter and / or the maximum outer diameter of the plastic pipe to be produced.

4. Device according to one of the preceding claims, characterized in that the outer diameter of the annular gap (70) is greater than or equal to the minimum inner diameter and / or the maximum inner diameter of the mold cavity (35).

5. Device according to one of claims 1 to 4, with a vertically directed corrugator (8) in the operating position with the mold cavity (35) forming mold jaws (36, 37) along the mold cavity (35), the mold cavity (35) radially completely enclosing, only in the axial direction of the

Corrugators (8), are moved vertically and are moved radially to one another outside the mold cavity (35), preferably moved radially and axially in a vertical plane in the manner of a pilgrim step or circumferentially, characterized in that the annular gap (70) between the upper edge (41) the path of movement of the mold jaws (36, 37) and the upstream end face (40) of the mold cavity (35) or above the upper edge (41) of the path of movement of the mold jaws (36, 37).

6. Device according to one of the preceding claims, characterized in that the mold cavity (35), preferably the entire corrugator (8), and the spray head (7) are adjustable relative to each other in the vertical and / or horizontal direction.

Apparatus according to claim 6, characterized in that, preferably for adjustment, the position of the mold cavity (35), preferably the corrugator (8), is adjustable in the vertical and / or horizontal direction.

8. Device according to one of the preceding claims, characterized in that the mold cavity (35), preferably the corrugator (8), about a horizontal axis, preferably in a rest and / or maintenance position, preferably in a horizontal position is pivotable.

9. Device according to one of the preceding claims, characterized in that the spray head (7) and / or the extrusion device (2), preferably the extrusion device (2) together with the spray head (7) relative to the mold cavity (35) in the operating position, Corrugator (8) is preferably adjustable, preferably for start-up operation.

10. The device according to claim 9, characterized in that the extrusion device (2) about a vertical axis (21) is pivotable.

11. Device according to one of the preceding claims, characterized in that the spray head (7) has an inner member (78), e.g. formed as a support air tube, mandrel and / or cooling mandrel, which is supported on the spray head (7) and extends to the downstream end of the spray head (7) and forms the annular gap (70) with the inner wall of the spray head (7).

12. The apparatus according to claim 11, characterized in that the inner member (78) downstream on the formation of an im Cross section of annular outlet channel (70) extends over a distance parallel to the inner wall of the spray head (7).

13. The apparatus of claim 11 or 12, characterized in that the downstream end of the inner member (78) ends in the region of the annular gap (70) or protrudes from the annular gap.

14. The apparatus according to claim 13, characterized in that the end of the inner member (78) projecting from the annular gap (70) protrudes into the mold cavity (35) or ends directly at the upstream end face (40) of the mold cavity or does not end in the mold cavity (35) , protrudes and ends at a distance from the upstream end of the mold cavity.

15. Device according to one of the preceding claims, characterized in that the mold cavity (35) is associated with a pressure generating device (18) for generating negative pressure and / or positive pressure, with the aid of which the plastic mass of the plastic melt jet entering the mold cavity (35) can be brought into contact with the inner wall of the mold cavity 35.

16. A method for producing plastic pipes, preferably corrugated plastic pipes, in particular with a nominal diameter of <10 mm, a plastic compound by means of an extrusion device (2) from an annular gap (70) of a spray head (7) connected downstream of the extrusion device, which is directed vertically in the operating position , as a plastic melt jet into a mold cavity (35) formed by moving mold jaws, for example corrugator jaws (36, 37), in which the material of the plastic melt jet is caused by external negative pressure and / or by internal one Excess pressure is brought into contact with the mold, characterized in that the annular gap (70) is arranged outside the mold cavity (35) by arranging the annular gap at a distance or immediately adjacent to an upstream end (40) of the mold cavity (35).

17. The method according to claim 16, characterized in that the diameter of the emerging plastic melt jet, preferably its inner diameter and / or its outer diameter, by adjusting the distance from the annular gap (70) to the upstream end (40) of the mold cavity (35) and / or is controlled.

18. The method according to any one of claims 16 or 17, characterized in that the diameter of the emerging plastic melt jet preferably determines its inner diameter and / or its outer diameter, by sliding the annular gap (70) and the upstream end of the mold cavity (35) and / or is controlled.

19. The method according to claim 18, characterized in that the Relatiwerschieben by vertical adjustment, preferably adjusting the position of the mold cavity (35), preferably the corrugator (8).

20. The method according to any one of claims 16 to 19, characterized in that the diameter of the emerging plastic melt jet, preferably its inner diameter and / or its outer diameter, by Setting the ratio of the inflow speed of the molten plastic jet as it emerges from the annular gap (70) relative to the production speed of the corrugator (8) is determined and / or controlled.

21. The method according to claim 20, characterized in that the production speed of the corrugator (8) is determined and / or controlled by adjusting the vertical speed of the corrugator jaws (36, 37) and / or the pressure conditions in the mold cavity (35) of the corrugator (8) ,

22. The method according to any one of claims 16 to 21, characterized in that an annular gap (70) which is preferably formed on a nozzle of the spray head (7) and has an outer diameter which is greater than or equal to the nominal width is used as the annular gap (70) of the plastic pipe to be produced, preferably the effective inner diameter and / or the outer diameter of the plastic pipe to be produced.

23. The method according to any one of claims 16 to 22, characterized in that an annular gap (70), preferably formed on a nozzle of the spray head (7), is used as the annular gap (70) which has an outer diameter which is greater than or equal to the minimum Inside diameter and / or the maximum inside diameter and / or the minimum outside diameter and / or the maximum outside diameter of the plastic pipe to be produced.

24. The method according to any one of claims 16 to 23, characterized in that as an annular gap (70), preferably at a nozzle of the spray head (7) trained annular gap (70) is used, which has an outer diameter that is greater than or equal to the minimum inner diameter and / or the maximum inner diameter of the mold cavity (35).

25. The method according to any one of claims 16 to 24, characterized in that a corrugator (8) oriented vertically in the operating position is used, the mold jaws (36, 37) of the corrugator (8) along the mold cavity (35), the mold cavity ( 35) are radially completely encircling, only in the axial direction vertically and outside the mold cavity (35) are moved radially to one another, preferably radially and axially to one another in a vertical plane are moved in a step-like manner or circumferentially to one another, the annular gap (70) between the upper edge (41) of the

Path of movement of the mold jaws (36, 37) and the upstream end (40) of the mold cavity (35) or above the upper edge (41) of the path of movement of the mold jaws (36, 37) is arranged.

26. The method according to claim 16 or 25, characterized in that an inner member (78) of the spray head (7), e.g. serves as a support air tube, mandrel and / or cooling mandrel, is supported in particular on the spray head (7) and extends to the downstream end of the spray head (7) and forms the annular gap (70) with the inner wall of the spray head (7).

27. The method according to claim 26, characterized in that the inner member is guided on the outflow side over a distance parallel to the inner wall of the spray head (7) to form an outlet channel (77) which is annular in cross section.

28. The method according to claim 26 or 27, characterized in that the downstream end of the inner member (78) ends in the region of the annular gap (70) or protrudes from the annular gap (70).

29. The method according to claim 28, characterized in that the end of the inner member (78) projecting from the annular gap (70) projects into the mold cavity (35) or ends directly at the upstream end face (40) of the mold cavity or outside the mold cavity

(35) arranged at a distance from the upstream end (40) of the mold cavity (35) ends.

30. The method according to any one of claims 16 to 29, characterized in that the mold cavity (35) is assigned a pressure generating device (18) for generating negative pressure or positive pressure, with the aid of which the material of the plastic melt jet on the inner wall of the mold cavity (35 ) is brought to the plant.