Extrusion die and extrusion system

Abstract

The invention relates to an extrusion die (100), in particular pipe extrusion die, for producing a hollow plastic profile, in particular a plastic pipe, comprising: at least two melt inlets (102a, 102b, 102c); at least two melt channels (104a, 104b, 104c); and a melt outlet (106), wherein a first melt channel (104a) extends between a first melt inlet (102a) and the melt outlet (106) and a second melt channel (104b) extends between a second melt inlet (102b) and the melt outlet (106), the first melt channel (104a) and the second melt channel (104b) being thermally separated from each other at least in sections. The invention also relates to an extrusion system comprising at least one extruder and an extrusion die (100).

Description

[0001] Extrusion tool and extrusion system

[0002] The invention relates to an extrusion tool, in particular a pipe extrusion tool, for example a pipe head. Furthermore, the invention relates to an extrusion system with such an extrusion tool.

[0003] Extrusion dies are usually installed directly downstream of an extruder assembly, for example, so that the melt, particularly plastic melt, provided by the extruder assembly can be formed into a desired shape by the downstream extrusion die. Extrusion dies include flat dies, tubular dies, profiles, etc.

[0004] In pipe extrusion dies, also called pipe heads for short, it is also common practice to heat them radially inside and / or outside the housing, i.e., well in front of the nozzle, for example, using ceramic heating bands. Especially in large pipe heads, the interior of the pipe head is heated using a temperature control system that operates with a temperature control medium. This type of temperature control has the advantage of not only adding heat to the melt but also removing it.

[0005] For example, document DE 10 2010 025 524 A1 discloses a device for producing a hollow plastic profile. The device comprises an extrusion die with a melt channel, an extruder that feeds the melt channel with plastic melt, and a suction device for extracting air through the profile interior in the opposite direction to the extrusion direction. The air duct system can provide internal cooling of the tube.

[0006] Furthermore, DE 197 44 515 A1 discloses a method and a device for producing an endlessly extruded profile strand by coextrusion of different materials, wherein extrusion temperatures of the different materials differ from one another and the different materials are fed to an extrusion tool via separate channels which can each be separately temperature-controlled and are thermally insulated from one another, where they are brought together, preferably under pressure, and extruded.

[0007] Further technological background can be found in US 5 641 445 A, US 5 516 474 A, WO 2008 / 004 329 A1, DE 35 32 996 A1 and DE 30 44 535 A1.

[0008] However, the design of conventional pipe extrusion tools for the production of multilayer plastic products that must be extruded from plastics with significantly different processing temperatures has several disadvantages. Above all, there is a risk of degradation of the plastics and limited formability of the plastic melt. With this design, various multilayer plastic products, such as multilayer pipes, cannot be manufactured, or can only be manufactured in a multi-stage process. Therefore, the conventional pipe extrusion tool cannot process plastics that, for technical reasons, require processing at different temperatures. Furthermore, uncontrolled heating of individual plastic layers would lead to defects in the pipe.With regard to the extrusion of multi-layer pipes, the usual design also significantly limits the throughput of the tools and restricts the diameter of pipes that can be produced.

[0009] The invention is based on the object of structurally and / or functionally improving an extrusion die mentioned above. Furthermore, the invention is based on the object of structurally and / or functionally improving an extrusion system mentioned above. It is therefore an object of the present invention to provide an extrusion die or an extrusion system that reduces or eliminates the disadvantages identified in connection with the prior art. In particular, it is an object of the present invention to provide a pipe extrusion die with which plastic melts can be processed at different temperatures in order to produce higher-quality multilayer pipes in a single-stage process. Furthermore, the throughput is to be improved and the coverage of a wide pipe dimension range per die is to be enabled. This object is achieved with an extrusion die having the features of claim 1.Furthermore, the object is achieved by an extrusion system having the features of claim 20. Advantageous embodiments and / or further developments are the subject of the subclaims.

[0010] One aspect relates to an extrusion die, in particular for producing a hollow plastic profile. The plastic profile can be a plastic pipe, for example, a multilayer pipe. The extrusion die can be used and / or configured for use in an extrusion system. The extrusion die can be a pipe extrusion die, such as a pipe head.

[0011] The extrusion die has at least two melt inlets. The at least two melt inlets can each be designed for connection to an extruder, in particular an extruder outlet. For example, the extrusion die can have exactly two melt inlets or exactly three melt inlets. The number of melt inlets can correspond to the number of layers of the multilayer profile or multilayer pipe to be produced.

[0012] The extrusion die has at least two melt channels. The at least two melt channels can each be designed to guide or conduct and / or receive a plastic melt. For example, the extrusion die can have exactly two melt channels or exactly three melt channels. The number of melt channels can correspond to the number of layers of the multi-layer profile or multi-layer pipe to be produced.

[0013] The extrusion tool has at least one melt outlet. The extrusion tool can have one, for example exactly one, melt outlet. The melt outlet can be designed such that the plastic melt and / or the produced plastic hollow profile can be discharged and / or transferred to a nozzle and / or a nozzle set. The extrusion tool can have the nozzle and / or the nozzle set. The nozzle and / or the nozzle set can be arranged at the melt outlet and / or fastened there. The nozzle and / or the nozzle set can be replaceable. The nozzle and / or the nozzle set can have a dome. The nozzle and / or the nozzle set can be designed to form and / or shape specific or different profile or pipe dimensions, such as pipe diameters. The nozzle set can have the nozzle and the mandrel.

[0014] In the present aspect, the extrusion die has a first melt channel and a second melt channel. Furthermore, the extrusion die has a first melt inlet and a second melt inlet. The first melt channel runs between the first melt inlet and the melt outlet. The second melt channel runs between the second melt inlet and the melt outlet. The first melt channel and the second melt channel are thermally separated from each other, at least in sections. This can be achieved by thermal separation. This makes it possible to achieve different temperatures for the plastic melt moving through the melt channels, thereby optimally influencing the different plastic materials to be processed.It is therefore possible to feed plastic materials with very different temperatures into the extrusion die after plasticization and to keep them at this temperature even during material distribution, so that temperature equalization only occurs in the layered extrudate.

[0015] The extrusion die further comprises a third melt inlet and a third melt channel. The third melt channel extends between the third melt inlet and the melt outlet. The first melt channel and the third melt channel are thermally separated from one another at least in sections. Additionally or alternatively, the second melt channel and the third melt channel can be thermally separated from one another at least in sections. Multiple melt channels can be provided. The multiple melt channels can be thermally separated from one another at least in sections.

[0016] The extrusion die can have at least two distribution elements. For example, the extrusion die can have exactly two or exactly three distribution elements. The number of distribution elements can correspond to the number of layers of the multi-layer profile or multi-layer pipe to be produced.

[0017] The extrusion tool can have a first distribution element and a second distribution element. The first melt channel can be formed and / or delimited at least in sections by the first distribution element and the second distribution element. The extrusion tool can have a connecting piece. The connecting piece can be pot-shaped and / or cylindrical, for example a hollow cylinder. The connecting piece can have a base section extending in the radial direction and a wall section extending in the axial direction, such as the extrusion direction. The connecting piece can be arranged in the axial direction, such as the extrusion direction, essentially between the first distribution element and the second distribution element. The connecting piece can be fastened to the second distribution element, for example, screwed to it.The first melt channel can be formed and / or delimited at least in sections by the first distribution element and the connecting piece.

[0018] The extrusion die may have a housing. The housing may be formed in multiple parts. The housing may have multiple housing sections or housing parts. The distribution elements may be arranged within the housing. The second melt channel may be formed and / or delimited at least in sections by the second distribution element and a housing section of the extrusion die.

[0019] The extrusion die may have a third distribution element. The third melt channel may be formed and / or delimited at least in sections by the third distribution element and a housing section of the extrusion die. The second melt channel may be formed and / or delimited at least in sections by the third distribution element and the second distribution element.

[0020] The first distribution element and the second distribution element can be thermally separated from one another at least in sections. The first distribution element and the third distribution element can be thermally separated from one another at least in sections. Additionally or alternatively, the second distribution element and the third distribution element can be thermally separated from one another at least in sections. Multiple distribution elements can be provided. The multiple distribution elements can be thermally separated from one another at least in sections.

[0021] The distribution elements, or the first distribution element and / or the second distribution element and / or the third distribution element, can be designed as a single piece or in multiple pieces, for example in two pieces. For example, a distribution element can comprise a pre-distribution element and a spiral distribution element. The pre-distribution element can have a main channel and / or at least one pre-distribution channel. The spiral distribution element can comprise at least one secondary channel. The at least one secondary channel can run helically in the circumferential surface of the spiral distribution element. The main channel can merge into the at least one pre-distribution channel and / or the at least one secondary channel. The at least one pre-distribution channel can merge into the at least one secondary channel. The distribution elements, or the first distribution element and / or the second distribution element and / or the third distribution element, can be designed as spiral distributors. The spiral distributor can be an axial spiral distributor.The spiral distributor can be substantially cylindrical, for example hollow cylindrical. The spiral distributor can be formed in one piece or in multiple pieces. The spiral distributor can have a main channel. The main channel can be an inlet channel, such as a melt inlet channel. The spiral distributor can have at least one secondary channel that is in fluid communication with the main channel, in particular a fluidic and / or fluid connection, such as a fluid connection. The at least one secondary channel can run helically in the circumferential surface of the spiral distributor. The main channel can merge into the at least one secondary channel. The at least one secondary channel can be an outlet channel, such as a melt outlet channel. The at least one secondary channel can be a spiral distributor channel. The spiral distributor can have a plurality of secondary channels. The plurality of secondary channels can be fluidically connected to the main channel on the inlet side or open into it.The plurality of secondary channels can form a spiral arrangement. The plastic melt can be fed into the spiral distributor via the main channel. From the main channel, the plastic melt can be guided further into the at least one secondary channel or into the plurality of secondary channels. In the at least one secondary channel or in the plurality of secondary channels, the plastic melt can be brought into a homogeneous and / or hollow shape. The main channel and / or the at least one secondary channel(s) can be part of a melt channel and / or form and / or define this at least in sections. The main channel and / or the at least one secondary channel(s) and / or the at least one pre-distribution channel(s) can be designed as a bore or groove, at least in sections.

[0022] The distribution elements or spiral distributors can be arranged substantially at a distance from one another in the axial direction, in particular the extrusion direction, and / or one behind the other. The distribution elements or spiral distributors can be arranged substantially concentrically or eccentrically, in particular with respect to the extrusion axis, in particular in the axial direction, such as the extrusion direction. The distribution elements or spiral distributors can be arranged substantially in an axial direction, in particular the extrusion direction, and / or radial direction, in particular in sections, overlapping and / or pushed into one another. Within an extrusion tool, spiral distributors can be provided that are spaced from one another in the axial direction, in particular the extrusion direction, and / or one behind the other, as well as spiral distributors that are arranged so as to overlap and / or pushed into one another. The at least one secondary channel orthe secondary channels, for example its outlet / outlets, of the first spiral distributor and the at least one secondary channel or channels, for example its outlet / outlets, of the second spiral distributor can be arranged substantially at a distance from one another in the axial direction, in particular the extrusion direction, and / or one behind the other. The at least one secondary channel or channels, for example its outlet / outlets, of the first spiral distributor and the at least one secondary channel or channels, for example its outlet / outlets, of the second spiral distributor can be arranged substantially overlapping in sections in the axial direction, in particular the extrusion direction, and / or the radial direction. The at least one secondary channel or channels, for example its outlet / outlets, of the second spiral distributor and the at least one secondary channel or channelsThe secondary channels, for example its outlet(s), of the third spiral distributor can be arranged substantially spaced apart from one another in the axial direction, in particular the extrusion direction, and / or one behind the other. The at least one secondary channel(s), for example its outlet(s), of the second spiral distributor and the at least one secondary channel(s), for example its outlet(s), of the third spiral distributor can be arranged substantially overlapping in the axial direction, in particular the extrusion direction, and / or radial direction.

[0023] The melt channels and / or melt streams can be joined one behind the other essentially in the axial direction, in particular in the extrusion direction. The joining of individual melt channels and / or melt streams can be realized one behind the other essentially in the axial direction, in particular in the extrusion direction, and / or radial direction, for example by means of an L- or T-shaped connecting arrangement or connecting piece.

[0024] The first melt channel and the second melt channel can merge into a common annular melt channel toward the melt outlet. This annular melt channel and the first and / or second melt channel can be thermally separated from each other, at least in sections. The annular melt channel can be substantially concentric with the extrusion direction or extrusion axis. The annular melt channel can be an annular gap melt channel. The annular melt channel can be configured to generate an annular gap flow of the plastic melt. At least two melt streams can be converged in the annular melt channel.

[0025] In the present aspect, the second melt channel and the third melt channel merge into a common annular melt channel in the direction of the melt outlet. This annular melt channel and the first and / or second and / or third melt channel can be thermally separated from one another at least in sections. In the present aspect, the first melt channel and the annular melt channel are thermally separated from one another at least in sections. The annular melt channel can be substantially concentric to the extrusion direction or extrusion axis. The annular melt channel can be an annular gap melt channel. The annular melt channel can be designed such that an annular gap flow of the plastic melt can be generated. The annular melt channel can be formed and / or delimited at least in sections by the connecting piece and a housing section of the extrusion die. At least two or three melt streams can be converged in the annular melt channel.The first melt channel may open further downstream into the annular melt channel, in particular than the second and / or third melt channel.

[0026] The respective thermal separation can be formed by a gap and / or cavity. The gap and / or cavity can be annular and / or spiral-shaped. The gap can be an annular gap, air gap, or vacuum gap. The cavity can be a chamber, such as a hollow chamber and / or vacuum chamber. The gap and / or cavity can have an inlet or inlet and / or outlet or outlet for a temperature control medium. The respective thermal separation can additionally or alternatively be formed by an insulating element. The insulating element can be arranged entirely or at least partially within the gap or cavity. The insulating element can be arranged entirely or at least partially within a melt channel. The insulating element can form and / or delimit a melt channel, at least in sections. The insulating element can be cylindrical and / or pot-shaped.The insulation element can be made of steel, in particular of a steel with a low thermal conductivity coefficient, such as stainless steel. The steel can have a lower thermal conductivity coefficient than the material, such as steel, of the distribution elements and / or the housing. Materials, such as steel, that have different thermal conductivity coefficients can be provided. The insulation element can be made of a metal, such as steel or alloys, plastic and / or insulating material, for example wool, such as mineral wool or glass wool, or at least comprise one of these. The insulating material can be a synthetic and / or natural fiber insulating material. The insulation element can also comprise a natural material. In particular, the material of the insulation element can be designed as a poor thermal conductor.The insulation element can be designed as an intermediate piece and / or connecting piece for at least one distribution element, for example for the first distribution element. The insulation element can be designed as an insulating sleeve or insulating bushing. The thermal separation and / or the insulation element can be designed as a coating, in particular an insulating coating. The coating can be provided at least partially within the melt channels. For example, the coating can be an internal coating of the melt channel. One or more melt channels can thus be coated at least partially with an insulating coating. The coating can be made of metal, such as steel or an alloy, and / or of plastic. In particular, the material of the coating can be designed as a poor heat conductor.

[0027] The insulating element or insulating sleeve or insulating bushing can be arranged around at least a section of a melt channel, for example, around at least a section of the first melt channel. The insulating element or insulating sleeve or insulating bushing can have at least one heating and / or cooling element. The heating and / or cooling elements can be controlled via temperature control devices. The heating and / or cooling elements can be designed as electrical and / or hydraulic heating and / or cooling elements. The heating element can be a heating band. The heating band can be a ceramic heating band or a mica heating band.

[0028] The gap or cavity can be filled and / or fillable with a temperature control medium, such as heating or cooling medium, for example with a gas such as air, and / or with a fluid such as water and / or oil. A vacuum can essentially be provided and / or created in the gap and / or cavity. The thermal separations, in particular the respective gaps, cavities, insulation elements, insulation sleeves or insulation bushings, can be provided with or connected to independent temperature control devices. For example, a temperature control medium at a predetermined temperature can flow and / or be fed through each gap or cavity or through selected gaps or cavities in order to appropriately temperature control the plastic melt in the associated melt channel, such as to heat or cool it or to maintain it at a predetermined temperature.

[0029] At least one section of a melt channel, for example, at least one section of the first melt channel, can be mounted in a substantially floating manner. The at least one section of the melt channel can be designed and / or mounted such that it can expand and / or displace at least in one direction, for example, in and / or opposite to the flow direction and / or extrusion direction. The mounting can be provided on a distribution element, for example, on the third distribution element, and / or on a housing section.

[0030] Another aspect relates to an extrusion system. The extrusion system can be configured and / or designed to produce a hollow plastic profile, such as a plastic pipe, for example, a multi-layer pipe. The extrusion system can comprise an extrusion die. The extrusion die can be designed as described above and / or below. The extrusion system can further comprise at least one extruder. The at least one extruder can be a single-screw extruder or a twin-screw extruder. The extrusion system can provide an extruder for each melt inlet of the extrusion die.

[0031] In summary and in other words, the invention thus results, among other things, in an extrusion tool, such as a pipe tool / pipe head, in which a different structure is provided so that different plastics remain separate from one another with their different temperatures for as long as possible. This can be achieved by thermally separating the layers or plastic melts, by tempering the layers or plastic melts and / or by bringing the layers or plastic melts together in the tool as late as possible. Thermal separation can be provided between a central and / or internal melt line (melt channel) and a distribution element, such as a spiral distributor. Additionally or alternatively, thermal separation can be provided between the distribution element, such as a spiral distributor, and an annular gap flow. Thermal separation of the inner and middle layer can be provided.At least one melt line (melt channel) can be mounted in a floating manner, at least in sections, for example as a floating melt feed or by floating mounting. The melt-carrying components can be pressure-resistant. For example, spiral distributors, in particular axial ones, can be provided. By late merging of the melt layers, e.g. by placing the layer close to the outlet of the tool, influences on the different layers, such as degradation of plastics, can be reduced. In this way, a separation of the temperatures can be provided by late merging of the layers or plastic melt. The spirals of the inner layer can be shifted far forward towards the nozzle set. The melt can be guided into and through the pipe head via melt lines (melt channels). The melt line(s) can run through the tool with thermal separation.The melt line(s) (melt channel) can be overhung. There is little or no contact between components of different temperatures. Furthermore, the melt line(s) (melt channel) can be heated and / or insulated. Active temperature control, such as cooling or heating, can also be provided. For example, a floating and / or thermally separated melt guide for the inner layer can be provided. Components that were previously one-piece can now be divided into at least two components. By using steels with different thermal conductivity coefficients, it can be possible to reduce unwanted heat conduction in the tool. Stainless steel, as it is a poor heat conductor, can be used as the steel. Components can be designed in such a way that the different thermal expansions of the components due to different temperatures can be compensated. In addition, an air layer orA gap, such as an air gap, can be provided and / or incorporated between the components. An air gap can result in poorer heat conduction, especially with many boundary layers with poor heat transfer. This can drastically reduce heat conduction. The gap can also be actively tempered with a medium, such as heated or cooled. The medium can be, for example, oil, water, air, etc. Alternatively, a vacuum can be provided and / or created in the gap. This can enable active cooling and / or heating with a medium.

[0032] The invention enables materials or plastic melts that, for technical reasons, must be processed at different temperatures within a single tool. Through thermal separation and / or temperature control of the materials or plastic melts at different temperatures, an optimal wall thickness distribution in the finished pipe can be achieved. Uncontrolled heating of individual layers or plastic melts is avoided. This prevents or at least significantly reduces defects in the pipe. Adhesions due to excessively high temperatures, which adversely affect production, can be prevented. Cleaning intervals can be extended due to the thermal separation. A multi-stage extrusion process can be eliminated because only one tool is required. Economic throughput can be improved.Covering a wide pipe dimension window per tool can be made possible.

[0033] In the following, embodiments of the invention are described in more detail with reference to a figure, which shows schematically and by way of example:

[0034] Fig. 1 is a sectional view of an extrusion tool.

[0035] Fig. 1 shows a sectional view of an extrusion die 100. The extrusion die 100 is designed as a pipe extrusion die, for example, as a pipe head, for producing a hollow plastic multilayer pipe. In the present embodiment, the extrusion die 100 can be fed with three plastic melts to thus produce a three-layer plastic pipe.

[0036] The extrusion die 100 comprises three melt inlets 102a, 102b, 102c, which can be fed with different, particularly differently tempered, plastic melts via associated or connected extruders (not shown in Fig. 1). The extrusion die 100 thus has a first melt inlet 102a, a second melt inlet 102b, and a third melt inlet 102c.

[0037] Furthermore, the extrusion tool 100 comprises three melt channels 104a, 104b, 104c, namely a first melt channel 104a, a second melt channel 104b and a third melt channel 104c as well as a melt outlet 106. The first melt channel 104a runs between the first melt inlet 102a and the melt outlet 106. The second melt channel 104b runs between the second melt inlet 102b and the melt outlet 106. The third melt channel 104c runs between the third melt inlet 102c and the melt outlet 106. The individual melt channels 104a, 104b, 104c are merged in the extrusion direction (in Fig. 1 from right to left) and end together in the melt outlet 106. The extrusion tool 100 is designed such that the two second and third melt channels 104b, 104c, or their plastic melt streams, are merged first. The first melt channel 104a, orwhose plastic melt stream is fed further downstream in the extrusion direction at an axial distance to the two merged melt channels 104b, 104c or plastic melt streams.

[0038] The extrusion die 100 has a first distribution element 108a, a second distribution element 108b, and a third distribution element 108c. The first melt channel 104a is partially formed and delimited by the first distribution element 108a and a connecting piece 110. The second melt channel 104b is partially formed and delimited by the second distribution element 108b and the third distribution element 108c. The third melt channel 104c is partially formed and delimited by the third distribution element 108c and a housing section 112 of the extrusion die 100.

[0039] The distribution elements 108a, 108b, 108c are each designed as axial spiral distributors, each comprising a main channel 114a, 114b, 114c and a plurality of secondary channels 116a, 116b, 116c that are in fluid communication with the respective main channel 114a, 114b, 114c and that extend helically in the circumferential surface of the respective spiral distributor 108a, 108b, 108c. The distribution elements 108a, 108b, 108c or spiral distributors 108a, 108b, 108c are arranged substantially one behind the other and spaced apart in the extrusion direction. As can be seen in Fig. 1, the secondary channels 116b or their outlets of the second distribution element 108b are arranged downstream of the secondary channels 116c or their outlets of the third distribution element 108c in the extrusion direction and are arranged at a distance from them. Furthermore, the secondary channels 116a or their outlets of the first distribution element 108a are arranged downstream of the secondary channels 116b orThe outlets of the second distribution element 108b are arranged downstream in the extrusion direction and spaced from them. The second melt channel 104b and the third melt channel 104c merge in the direction of the melt outlet 106 into a common annular melt channel 118 or annular gap melt channel 118, in which the two melt flows are combined. The annular melt channel 118 is formed and delimited in sections by the connecting piece 110 and a housing section 120 of the extrusion tool 100. The first melt channel 104a opens further downstream into the annular melt channel 118, so that the melt flow of the first melt channel 104a is combined with the already combined melt flows of the second and third melt channels 104b, 104c. The melt outlet 106 is provided directly adjacent to this.A nozzle set 122 is arranged at the melt outlet 106, which forms a specific pipe dimension, such as the pipe diameter, and shapes the plastic pipe. The nozzle set comprises a nozzle 122a and a dome 122b.

[0040] The extrusion die 100 has a plurality of thermal separations for processing plastic melts at different temperatures within the extrusion die 100. In particular, the first melt channel 104a and the second melt channel 104b are thermally separated from one another at least in sections. Likewise, the first melt channel 104a and the third melt channel 104c are thermally separated from one another at least in sections. The first melt channel 104a and the annular melt channel 118 or the connecting piece 110 are also thermally separated from one another at least in sections. As shown in Fig. 1, the first distribution element 108a and the second distribution element 108b, as well as the first distribution element 108a and the third distribution element 108c, are thermally separated from one another at least in sections.

[0041] In the present exemplary embodiment, the thermal separation of the first melt channel 104a or the first distribution element 108a from the annular melt channel 118 or connecting piece 110, and thus from the second and third melt channels 104b, 104c, is realized by a gap 124. The gap 124 is designed as an annular gap. The connecting piece 110 is arranged downstream of the second distribution element 108b in the extrusion direction and is screwed to it. An insulating element 126 is additionally effectively arranged in the gap 124 and axially in the extrusion direction between the connecting piece 110 and the first distribution element 108a. The first melt channel 104a is thus formed and delimited in sections by the first distribution element 108a and the insulating element 126. The insulation element 126 is screwed to the connecting piece 110 and also serves to fasten the first distribution element 108a.Furthermore, the insulation element 126 is made of a steel with a low thermal conductivity coefficient, such as stainless steel.

[0042] Further upstream, particularly against the extrusion direction, the thermal separation of the first melt channel 104a from the second and third melt channels 104b, 104c and from the second and third distribution elements 108b, 108c is realized by a gap or cavity 128. In the present exemplary embodiment, the gap or cavity 128 is wider in the radial direction than the annular gap 124. The first melt channel 104a is additionally surrounded in sections by at least one insulating element 130 designed as an insulating sleeve. The insulating sleeve can have one or more cooling and / or heating elements. The heating element can be a heating band. The heating band can be a ceramic heating band or a mica heating band. Even further upstream, in particular in the region of the first melt inlet 102a, an insulating element 132 designed as an insulating bushing is arranged around a section of the first melt channel 104a.This creates a further thermal separation of the first melt channel 104a from the other two melt channels 104b, 104c.

[0043] For temperature control, a temperature control medium, such as a heating medium or coolant, for example a gas such as air, and / or a fluid such as water and / or oil, can additionally be fed into the annular gap 124 and / or the cavity 128 by means of a temperature control device. Alternatively, a substantially vacuum can be provided and / or generated in the annular gap 124 and / or the cavity 128.

[0044] "May" refers, in particular, to optional features of the invention. Accordingly, there are also further developments and / or embodiments of the invention that additionally or alternatively comprise the respective feature(s). If necessary, isolated features can also be extracted from the combinations of features disclosed herein and used in combination with other features to define the subject matter of the claim, dissolving any structural and / or functional relationship that may exist between the features.

[0045] List of reference symbols

[0046] Extrusion tool ac melt inlets ac melt channels

[0047] Melt outlet ac distribution elements

[0048] connector

[0049] Housing section ac main channels ac secondary channels

[0050] Ring melt channel

[0051] Housing section

[0052] Nozzle set a Nozzle b Dome

[0053] Gap / annular gap

[0054] Insulation element

[0055] gap / cavity

[0056] Insulation element / insulating sleeve

[0057] Insulating element / insulating bushing

Claims

Claims Extrusion tool (100), in particular pipe extrusion tool, for producing a hollow plastic profile, in particular a plastic pipe, comprising at least two melt inlets (102a, 102b, 102c); at least two melt channels (104a, 104b, 104c); and a melt outlet (106), wherein a first melt channel (104a) runs between a first melt inlet (102a) and the melt outlet (106) and a second melt channel (104b) runs between a second melt inlet (102b) and the melt outlet (106), characterized in that the first melt channel (104a) and the second melt channel (104b) are at least partially thermally separated from each other.Extrusion tool (100) according to claim 1, characterized in that the extrusion tool (100) has a third melt inlet (102c) and a third melt channel (104c) extending between the third melt inlet (102c) and the melt outlet (106), wherein the first melt channel (104a) and the third melt channel (104c) are thermally separated from each other at least partially. Extrusion tool (100) according to at least one of the preceding claims, characterized in that the extrusion tool (100) has a first distribution element (108a) and a second distribution element (108b), wherein the first melt channel (104a) is formed and / or bounded at least partially by the first distribution element (108a) and the second distribution element (108b) or by the first distribution element (108a) and a connecting piece (110, 126).Extrusion tool (100) according to claim 3, characterized in that the second melt channel (104b) is at least partially separated from the second. The extrusion die (100) is formed and / or limited by the distribution element (108b) and a housing section of the extrusion die (100). The extrusion die (100) according to at least one of the preceding claims is characterized in that the extrusion die (100) has a third distribution element (108c), wherein the third melt channel (104c) is formed and / or limited at least partially by the third distribution element (108c) and a housing section (112) of the extrusion die (100). The extrusion die (100) according to at least one of the preceding claims 3 to 5 is characterized in that the first distribution element (108a) and the second distribution element (108b) and / or the first distribution element (108a) and the third distribution element (108b) are thermally separated from each other at least partially.Extrusion tool (100) according to at least one of the preceding claims 3 to 6, characterized in that the first distribution element (108a) and / or the second distribution element (108b) and / or the third distribution element (108c) is / are designed as a helical distributor (108a, 108b, 108c), wherein the helical distributor (108a, 108b, 108c) comprises a main channel (114a, 114b, 114c) and at least one secondary channel (116a, 116b, 116c) in, in particular fluidic, connection with the main channel (114a, 114b, 114c), wherein the at least one secondary channel (116a, 116b, 116c) is helically arranged in the circumferential surface of the helical distributor (108a, 108b, 108c). Extrusion tool (100) according to at least one of the preceding claims 3 to 7, characterized in that the distribution elements (108a, 108b, 108c) orSpiral distributors (108a, 108b, 108c) are spaced apart from each other substantially in the axial direction, in particular in the extrusion direction, and / or arranged one behind the other and / or pushed into one another, and / or that the at least one secondary channel (116a) of the first spiral distributor (108a) and the at least one secondary channel (116b) of the. The second spiral distributor (108b) is spaced apart from each other substantially in the axial direction, in particular the extrusion direction, and / or arranged one behind the other and / or nested within each other, and / or the at least one secondary channel (116b) of the second spiral distributor (108b) and the at least one secondary channel (116c) of the third spiral distributor (108c) are spaced apart from each other substantially in the axial direction, in particular the extrusion direction, and / or arranged one behind the other and / or nested within each other. Extrusion tool (100) according to at least one of the preceding claims 3 to 8, characterized in that the distribution elements (108a, 108b, 108c) orThe spiral distributors (108a, 108b, 108c) are substantially spaced apart from each other in a radial direction and / or arranged one behind the other and / or nested within each other and / or that the at least one secondary channel (116a) of the first spiral distributor (108a) and the at least one secondary channel (116b) of the second spiral distributor (108b) are substantially spaced apart from each other in a radial direction and / or arranged one behind the other and / or nested within each other, and / or that the at least one secondary channel (116b) of the second spiral distributor (108b) and the at least one secondary channel (116c) of the third spiral distributor (108c) are substantially spaced apart from each other in a radial direction and / or arranged one behind the other and / or nested within each other. Extrusion tool (100) according to at least one of the preceding claims 3 to 9, characterized in that the distribution elements (108a, 108b, 108c) orSpiral distributors (108a, 108b, 108c), in particular in the axial direction, such as the extrusion direction, are arranged substantially concentrically or eccentrically, particularly with respect to the extrusion axis. Extrusion tool (100) according to at least one of the preceding claims 2 to 10, characterized in that the second melt channel (104b) and the third melt channel (104c) transition towards the melt outlet (106) into a common annular melt channel (118), such as an annular gap melt channel (118), wherein the first. The melt channel (104a) and the annular melt channel (118) are at least partially thermally separated from each other. An extrusion tool (100) according to claim 11, characterized in that the annular melt channel (118) is formed and / or bounded at least partially by the connecting piece (110) and a housing section (120) of the extrusion tool (100). An extrusion tool (100) according to claim 11 or 12, characterized in that the first melt channel (104a) opens further downstream into the annular melt channel (118) in the axial direction, like the extrusion direction.An extrusion tool (100) according to at least one of the preceding claims, characterized in that several melt channels (104a, 104b, 104c) and / or several distribution elements (108a, 108b, 108c) are provided, wherein the several melt channels (104a, 104b, 104c) are thermally separated from one another at least partially and / or the several distribution elements (108a, 108b, 108c) are thermally separated from one another at least partially. An extrusion tool (100) according to at least one of the preceding claims, characterized in that the thermal separation is formed by a gap (124), and / or a cavity (128) and / or by an insulating element (126, 130, 132).Extrusion tool (100) according to claim 15, characterized in that the insulating element (126, 130, 132) is designed as an insulating sleeve (130) or insulating bushing (132) and / or that the insulating element (126, 130, 132) is made of plastic, insulating material, in particular wool, such as mineral wool, and / or metal, such as steel, in particular a steel with a low thermal conductivity coefficient, such as stainless steel, or at least one of these. Extrusion tool (100) according to claim 15 or 16, characterized in that the insulating element (126) is designed as an intermediate piece (126) and / or connecting piece (126) for at least one distribution element (108a, 108b, 108c), in particular for the first distribution element (108a). Extrusion tool (100) according to claim 15 or 16, characterized in that the insulating element (126, 130, 132) or the insulating sleeve (130) or insulating bushing (132) is arranged around at least one section of a melt channel (104a, 104b, 104c), in particular around at least one section of the first melt channel (104a), and / or has at least one heating and / or cooling element.Extrusion tool (100) according to at least one of the preceding claims 15 to 18, characterized in that the gap (124) and / or cavity (128) is filled and / or fillable with a temperature control medium, such as a heating medium or coolant, in particular with a gas, such as air, and / or with a fluid, such as water and / or oil, and / or that a vacuum is substantially provided and / or generated in the gap (124) and / or cavity (128). Extrusion tool (100) according to at least one of the preceding claims, characterized in that the thermal break and / or the insulating element (126, 130, 132) is designed as a coating, in particular an insulating coating. Extrusion tool (100) according to at least one of the preceding claims, characterized in that at least one section of a melt channel (104a, 104b, 104c), in particular at least one section of the first melt channel (104a), is substantially floating.Extrusion plant comprising at least one extruder; and. An extrusion die (100) according to at least one of the preceding claims. An extrusion plant according to claim 22, characterized in that an extruder is provided for each melt inlet (102a, 102b, 102c) of the extrusion die (100). An extrusion plant according to claim 22 or 23, characterized in that one, in particular a common, extruder is provided for at least two melt inlets (102a, 102b, 102c) of the extrusion die (100).

Images