WO2021175357A1

WO2021175357A1 - Extruder comprising at least one screw for processing a processing material

Info

Publication number: WO2021175357A1
Application number: PCT/DE2021/000042
Authority: WO
Inventors: Jochen Hennes
Original assignee: Jochen Hennes
Priority date: 2020-03-06
Filing date: 2021-03-03
Publication date: 2021-09-10
Also published as: DE102020001456B4; DE102020001456A1

Abstract

Disclosed is an extruder comprising at least one screw for processing a processing material, wherein at least one screw has at least two homogenization zones HZ1 (221) and HZ2 (223), wherein a vertically limited gap-wall region designates the flight land region in which a gap-wall region has at least two mixing gap portions, wherein at least 50% of the mixing gap portions have a flight land height, relative to the two surrounding screw channels, of at least 30% and at most 70% of the distance at the root, wherein a vertically limited flow region designates the flight land region in which a flow region has a flight land height, relative to the two surrounding screw channels, of at least 30% and at most 70% of the distance at the root in said location, wherein homogenization zone HZ1 (221) is a mixing zone which has at least one vertically limited gap-wall region on at least part of at least one flight land (231) and/or has at least one vertically limited flow region on at least part of a flight land, and homogenization zone HZ2 (223) has at least as many flight lands as homogenization zone HZ1 (221), wherein homogenization zone HZ1 (221) lies in front of homogenization zone HZ2 (223).

Description

EXTRUDER WITH AT LEAST ONE SCREW FOR PROCESSING ONE PROCESSING MATERIAL

The invention relates to an extruder with at least one mixing zone and in particular the design and arrangement of at least one mixing zone of at least one screw of the extruder for thermal and / or distributive mixing.

Any processing material should be able to be processed in the extruder. At least one component of the processing material can be melted and is at least partially melted in the extruder and / or fed to the extruder at least partially in the melted state and is mostly at least partially in solid form after an optional molding, e.g. but not exclusively after an extrusion tool or in an injection molding tool and the corresponding cooling methods for the respective process. In addition to these meltable components, non-meltable materials, e.g. wood, calcium carbonate, fibers, e.g. carbon fibers, soot, mineral substances or the like can also be part of the processing material. Other components can also be materials that only melt at very high temperatures, such as sand, glass spheres or the like, hollow glass bodies, fibers, e.g. glass fibers or the like. As described, these constituents can also be melted, but usually remain in the solid state in the extruder due to their high melting temperature. In the context of the present document, meltable constituents of the processing material are understood to mean those constituents which are usually at least partially melted in the extrusion process. The melting temperature of these meltable constituents is preferably below 450.degree. C., preferably below 400.degree. C., particularly preferably below 350.degree.

Preferably at least part of the processing material is at least one thermoplastic polymer. The thermoplastic polymer is particularly preferably processed in the extruder at least together with additives and / or fillers.

At least part of the processing material is preferably at least one foodstuff that can be melted.

Preferably at least part of the processing material is a pharmaceutical active ingredient.

A large part of the components of the processing material is often fed to the extruder as a solid. In addition to or instead of this, components of the processing material in the already molten, liquid and / or gaseous state can also be fed to the extruder. Some of the processing material can be discharged in the extruder upstream of the main discharge zone. It is also possible to supply solid and liquid materials that only become liquid or gaseous through further temperature supply, shear and / or pressure reduction, such as propellants. The processing material can be fed to the extruder at one or more points.

In the case of the averaged melting temperature of the processing material, only those melting temperatures of the constituents of the processing material whose melting temperature are below 450 ° C., preferably below 400 ° C., particularly preferably below 350 ° C., are taken into account. These components are in the Essentially, but not exclusively, meltable thermoplastic polymers or meltable food. The basis for determining the mean value is the weight and not the volume of the individual components. Components whose melting temperature are not taken into account are essentially, but not exclusively, glass components, such as glass fibers or glass spheres, as well as sand and other at least partially mineral fillers.

In the context of the present document, all devices are referred to as extruders in which at least one screw rotates in a housing and a processing material is conveyed and / or plasticized and / or melted and / or cooled.

The extruder with mixing zone is preferably used in a plasticizing unit in which the processing material is to be melted and / or the homogeneity of the processing material is to be improved.

More preferably, the extruder with mixing zone is used in a device for extruding fiber composite molded parts or fiber composite semifinished products, particularly preferably for extruding fiber composite plastic molded parts or fiber composite plastic semifinished products.

The extruder with mixing zone is preferably used in a device for injection molding, e.g. a so-called injection molding machine or a so-called injection molding unit.

The injection pressure can be generated via at least one displaceably mounted screw as well as via one or more pistons that are filled via at least one screw.

The extruder with a mixing zone in a device for injection molding is preferred

Fiber composite molded parts, preferably fiber composite plastic molded parts used. The injection pressure can be generated via at least one displaceably mounted screw as well as via one or more pistons that are filled via at least one screw.

The extruder with mixing zone is preferably used as a cooling extruder in which the temperature of the processing material that has already been heated and / or melted beforehand is to be reduced and / or the homogeneity of the processing material is to be improved. The cooling extruder is a special case in foam production. Here, a particularly high degree of homogeneity of the processing material is required.

Another preferred use of the extruder with a mixing zone is as an extruder with at least one secondary discharge zone, for example to at least partially remove water or monomeric constituents from the processing material.

A wide variety of extruders are known and proven. In plastics processing, for example, they are used to plasticize a processing material that is initially mostly granular or powdery, mostly plastic raw material, as well as to convey the melt produced and to build up pressure for it a subsequent tool, for example an extrusion tool. A similar structure can be found in the processing of meltable foods.

More and more often, screws in extruders have so-called mixing or shear parts in order to homogenize the processing material and to provide it as a mechanically and thermally homogeneous melt after it has been discharged from the extruder. Furthermore, the melt should mostly have a temperature that is as low as possible. These properties should be achieved over the broadest possible spectrum of processing materials.

In the context of the present document, reference is often made to an axial direction. The axial direction means the discharge direction along the extruder.

Most often, single screw extruders are used because they are the most economical to manufacture and easy to operate. In the case of extruders with a screw, the discharge direction of the extruder and thus the axial direction result from the direction of the screw axis from the main feed zone to the main discharge zone. The axial direction is indicated by the arrow 110 in FIG. 1 by way of example for an extruder with a screw.

If there are several screws in an extruder, all screw axes are mostly parallel to one another. In this case, the discharge direction of the extruder and thus the axial direction result from a direction of any screw axis from the main feed zone to the main discharge zone.

In rare cases, e.g. with conical twin screw extruders, there are several screws in one extruder and at least two screw axes are not parallel to each other. In this case, the discharge direction of the extruder and thus the axial direction are preferably obtained from the mean value of the direction of all screw axes from the main feed zone to the main discharge zone.

If reference is made to a length, a position, a beginning or an end of positions, sections, areas, zones, areas or parts in the present document, this is the length, the position, the beginning or the end of positions, sections To understand areas, zones, areas or parts in the axial direction, unless it is expressly apparent from the respective context or it is obvious or technically imperative for the person skilled in the art that a different reference is meant there.

For the following descriptions, reference is made to FIG. 1, in which an extruder with a screw is shown schematically and not to scale.

The length of the zone 122, for example, is the axial length of the zone 122 along the axial direction 110 according to the above explanations. The same usage also applies to the length of sections, areas, areas and parts.

The zones 123 and 124 lie in the axial direction after or behind the zone 122. The zones 122 and 123 lie in the axial direction in front of the zone 124. The zone 123 lies in the axial direction directly after the zone 122 and directly in front of the zone 124. The the same usage also applies to items, sections, areas, areas and parts. The beginning of the zone 123 is on the dashed line 104 and thus at the end of the zone 122 and the end of the zone 123 on the dashed line 105 and thus at the beginning of the zone 124. This also means that the end of the zone 122 with the The beginning of the zone 123 coincides, that is to say it is present in the same axial position. The same usage applies to the beginning and the end of sections, areas, areas and parts.

The screw in the extruder is built into a so-called cylinder in a so-called cylinder bore during operation. When reference is made in the following to a cylinder wall or cylinder wall, this means the inner wall of this cylinder which normally comes or can come into contact with the processing material during operation of the screw, in other words the wall of the cylinder bore.

In single-screw extruders, as already described above, a bore with a bore diameter is made in the cylinder and this is generally referred to as a cylinder bore. In the case of extruders with several screws, one often speaks of a cylinder bore, although the cross-section of the cylinder bore does not necessarily have to be round, but rather has a figure-of-eight shape, for example in the case of twin-screw extruders. The cylinder does not necessarily have to be round on the outside, but can also have an angular shape on the outside, for example. However, the round cylinder is usually the most cost-effective to manufacture and can usually also be most easily equipped with, for example, units for heating or cooling the outer surface. When a cylinder or an extrusion cylinder is described in the context of the present document, this also means all shapes that the housing of the extruder can have in order to accommodate the at least one screw of the extruder. When a cylinder bore is described in the context of the present document, this also means all shapes that the housing can have on the inside in order to accommodate the at least one screw of the extruder.

A large number of differently designed extruders with mixing zones can be found in the prior art.

A single screw with a mixing function for preferred use in a single screw plasticizing extruder or cooling extruder is known from the applicant's patent specification DE10 2018006234 A1. Different variants of mixing zones are described which have height-limited gap-wall areas and / or height-limited flow areas for the homogenization of a processing material. The difficulty for a successful use of the single screw with mixing function lies in the specific design of the mixing zone and in particular in the optimization of the numerous parameters for operation, such as melt temperature, residence time and energy input. This optimization is particularly difficult if fillers, fibers or the like are added to the processing material or if optimal homogenization is required, for example for foam generation. In addition, optimization proves to be difficult when optimal pressure profiles along the extruder or a high pressure build-up or improved conveyance of the processing material are required. However, DE10 2018 006234 A1 does not deal with an optimization of the pressure curve or an improved conveyance within the screw. In other words, the script does no further details on helpful geometric designs of the mixing zone that go beyond the height-limited areas and the associated improved vortex formation.

US Pat. No. 6,672,753 B1 describes a screw which has a reorientation zone between a barrier zone and a shaft mixing / shearing part. In the claims, in particular, the outer diameter of the respective webs (main web, barrier web, second web in the wave mixer / shear part) is described in relation to one another. Both the barrier web and the second web in the wave mixer / shear part have a narrow shear gap. Since the melt has to flow through the narrow gaps several times due to the structure described and the passage depth of the channels is sometimes low, there is sometimes an unfavorable pressure profile in the area of the shaft mixer / shear part. In addition, this can lead to an undesirable increase in the temperature of the processing material. Proposals for designs that lead to an improved conveyance of the processing material or to an improved pressure curve within the mixing part are not made.

Wo 2006/022 839 A2 also describes a screw that has a reorientation zone between a barrier zone and a shaft mixing / shear part. Both the barrier web and the second web in the wave mixer / shear part have a narrow shear gap. Since the melt has to flow through the narrow gaps several times due to the structure described and the channel depths are sometimes low, there is sometimes an unfavorable pressure profile in the area of the shaft mixer / shear section. In addition, this can lead to an undesirable increase in the temperature of the processing material. Proposals for designs which lead to an improved conveyance of the processing material or to an improved pressure curve within the shearing / mixing part are not made.

US 2004/0141406 A1 likewise describes a screw which has a reorientation zone according to the invention between a barrier zone and a shaft mixing / shearing part. In the claims, this reorientation zone is only mentioned in a subordinate manner.

Rather, a shear / mixing zone is specified within the metering area, which has at least one web with a sealing area (main web) and one web with a flow area (barrier web). In addition, there are mixed gap areas in the main web and / or barrier web. This build-up is intended to result in more thorough mixing. The mixing gap sections either have a web height of 0 or a web height which is approximately 0.13 mm less than the web height of the mixing wall sections which surround the mixing gap section. Since the melt has to flow through the narrow gaps several times due to the structure described and the passage depth of the channels is sometimes low, there is sometimes an unfavorable pressure profile in the area of the shaft mixer / shear part. In addition, this can lead to an undesirable increase in the temperature of the processing material. Proposals for designs that lead to an improved conveyance of the processing material or to an improved pressure curve within the shear / mixing zone are not made.

US 2004/0126453 A1 describes a screw that has a barrier zone and a spiral shear part. At the beginning and at the end of the barrier zone are interchangeable Barriers are provided which are introduced into the solids channel in the axial direction. By means of these barriers, the pressure between the main feed zone and the end of the barrier zone should be adjustable. The web height of the barrier web is not described in detail.

A description of the spiral shear part is not made in US 2004/0126453 A1.

The barriers introduced have a disadvantageous effect on the conveying rate of the screw, since they inhibit the flow and thus the conveyance of the processing material. This leads to an undesirable increase in the temperature of the processing material.

No. 4,171,196 A describes a screw in a cylinder which has at least one feed zone, a plasticizing zone and a mixing zone. The plasticizing zone is constructed like a barrier zone, the barrier web having the same web height as the main web. According to the invention, the barrier web has a large number of narrow openings which run from the screw base to the web head. The openings are deliberately narrow and high so that the entire melt comes into contact with the metal of the screw flight and assumes its temperature. Since the entire melt has to flow through the narrow gaps by means of a pressure flow due to the structure described, there is a high pressure consumption above the gap and an undesirable increase in the temperature of the processing material can also occur. Proposals for designs that lead to an improved conveyance of the processing material or to an improved pressure curve within the mixing part are not made.

No. 5,178,458 A describes a mixing part with at least one screw flight. The basic diameter of the mixing part increases from the inlet to the outlet. The outside diameter of the mixing part decreases from the inlet to the outlet. The web has openings along the screw axis, the width of which increases linearly from entry to exit. This structure is intended to improve the homogeneity of the processing material. In the illustrations, the channel, which is present in the form of a helix between the webs, has a similar width to the webs themselves. This structure makes it difficult to convey the processing material. In addition, the backflow worsens the conveyance of the processing material due to the sometimes very large openings. Proposals for designs that lead to an improved conveyance of the processing material or to an improved pressure curve within the mixing part are not made.

No. 3,941,535 A describes a combined mixing / shearing part which is intended to intensively shear and mix the processing material. There should be mixed gap areas in the screw flight. The mixing gap areas start flat at the entry of the shear mixing part and then deepen evenly and progressively to the screw base at the exit. At the end of the mixing / shearing part, there can be melt with a different shear history. The mixing gaps with low land heights lead to a reduction in the conveyance of the processing material. The mixing gaps with a large web height and thus a narrow gap lead to high shear input and thus to an increase in temperature of the processing material. Suggestions for statements leading to a Improved conveyance of the processing material or an improved pressure curve within the mixing / shearing part are not made.

JP H05-228 920 A describes an extruder with two secondary discharge zones (ventilation openings). During and after the secondary discharge zone, the extruder should have a kneader zone with depressions or grooves both on the inner wall of the cylinder and on the screw in order to simultaneously improve the homogeneity of the processing material, improved self-cleaning and a high throughput by improving the conveying of the processing material guarantee. The narrow gaps that arise in the area of the kneader zone, which during operation have no grooves or depressions either on the cylinder or on the screw, lead to considerable increases in the temperature of the processing material. It is unclear whether an improvement in the conveyance of the processing material through the kneading zone can be achieved. The fact that JP H05-228920 A explicitly provides for the possibility of closing the second secondary discharge zone with a plug indicates that the conveyance of the processing material in the area of the kneader zone is not being improved.

DE 101 50627 A1 describes an extruder for removing low molecular weight constituents and achieving higher molecular sizes with an extruder screw which has a section on which several screw spindles roll.

DE 102013 008201 A1 describes a method and a device for producing a foam body with several extruders, at least one extruder being equipped with an extruder screw device and several screw spindles distributed on the circumference of the extruder screw device. Here too, temperature differences between different radial positions in the cross section of the plastic melt are to be reduced.

DE 102013008202 A1 also describes a method and a device for producing a foam body with several extruders, wherein at least one extruder can be equipped with an extruder screw device and several screw spindles that are distributed over the circumference of the extruder screw device. Here too, temperature differences between different radial positions in the cross section of the plastic melt are to be reduced.

In DE 101 50627 A1, also in DE 10 2013 008 201 A1 and DE 102013 008 202 A1, only screw spindles are described and shown which, as is usual with screw spindles, have continuously circumferential screw flights. As a result, only a small amount of processing material escapes from one worm spindle and into the next worm spindle. A radial mixing is thereby guaranteed. Mixing over the entire processing material in the circumferential direction is made more difficult. The documents also do not deal with a combination of improved funding with an optimal mix of volumes.

The invention is based on the object of providing an improvement or an alternative to the prior art. The main task of the designs and arrangement of mixing zones proposed here is to improve the conveyance of the processing material, if possible in combination with an improved pressure profile within the mixing zones and along the extruder, with e.g. a pressure build-up, pressure neutrality or the lowest possible pressure loss within the mixing zones is to be achieved. In addition, the thermal and / or material homogeneity of processing materials is to be improved and, in particular, but not exclusively, components such as fibers and / or blowing agents and / or gases are to be mixed in in an improved manner. Another non-exclusive task is to improve the so-called degassing of processing materials. In this case, at least a part of at least one component is withdrawn from the processing material in a zone of the extruder, for example but not exclusively water and / or monomeric components.

First of all, it should be expressly pointed out that in the context of the present document, indefinite articles and numerical indications such as "one", "two" etc. should as a rule be understood as "at least" indications, i.e. as "at least one ...", "At least two ..." etc., unless it is explicitly stated in the respective context or it is obvious or technically imperative for a person skilled in the art that only "exactly one ...", "exactly two ..." etc. can be meant.

Several zones of the extruder as well as zones, areas and sections of the screw or the screw flight are described below. Zones are axial parts of the extruder and / or the screw and areas are parts of the zones and sections are parts of the areas.

An “area” describes the length in the axial direction of zones, areas, sections, parts or components. For example, the area of a zone begins with the beginning of the zone in the axial direction and ends with the end of the zone in the axial direction.

A “flight distance” at an axial position describes the minimum radial distance between a screw flight and the cylinder wall at the axial position.

The worm clearance at an axial position corresponds to the flight distance from the worm flight which is smallest in the axial position. If there are several screw flights at an axial position distributed over the circumference with different flight spacing, the screw play at the axial position corresponds to the smallest flight spacing. The snail clearance can vary over the length of the snail.

There are also axial positions on the worm where there is no land. Usually, at these positions, the screw play is determined by the highest elevation, e.g. a pin, a diamond, a ring or the like. If there is no elevation at an axial position, but only the screw base, there is also no screw play at the position.

The screw play lies in the axial part of the extruder in which the processing material is at least partially in the form of a melt, usually but not exclusively between 0.05 mm and 0.3 mm, but can also be over 1 mm in mixed and / or sheared parts, for example . Most often, an extruder with a screw is used. This is often referred to as a single screw extruder. In the case of single-screw extruders with a cylinder with a bore diameter of, for example, 70 mm minus or plus manufacturing tolerances and a screw with a screw clearance to the cylinder wall, the screw diameter is usually also 70 mm.

Various information, for example length information, is usually given depending on the screw diameter. For example, the length of a mixing section of 210 mm in a single-screw extruder which has a cylinder with a bore diameter of 70 mm is given as a length of 3 screw diameters.

A “basic distance” at an axial position denotes the maximum radial distance between the screw base of a screw channel and the cylinder wall at the axial position. The screw flight height corresponds to the basic distance minus the flight distance.

If there is no screw flight and no screw channel at the axial position, the basic distance is the maximum radial distance between the screw base and the cylinder wall at the axial position.

Screw flights and screw channels generally run helically around the screw. The helix can have the same pitch at all axial positions, in other words it can run monotonically around the worm. However, the helix can also at least partially have different pitches at different axial positions, that is to say, in other words, it cannot run monotonically around the worm. The pitch of the helix is often referred to as the pitch.

A screw channel is delimited on both sides by a screw flight. These screw flights are referred to as the surrounding screw flights. The thread depth of the worm channel at an axial position results from the basic distance at the axial position minus the flight distance worm backlash at the axial position.

A screw flight is largely surrounded by two screw channels. These two screw channels, which are referred to as the surrounding screw channels, each have a basic distance. If the basic distances of the two surrounding screw channels are different at an axial position, the flight height of the screw flight is also different for both surrounding screw channels and results from the respective basic distance minus the flight distance.

If there is a gap in a screw flight which at least partially has a depth which corresponds to the basic distance from a surrounding screw channel, the screw flight ends at the axial position at which the gap has a depth which corresponds to the basic distance. The screw flight starts again at the axial position at which the gap ends or has a depth that is smaller than the basic distance. In other words: at the point where the depth of the gap corresponds to the basic distance of at least one surrounding screw channel, there is no screw flight. Many snails have a tunnel that runs around the snail as a snail channel. But it is also possible that several threads run around the screw core. In such cases, the worm is referred to as multi-thread. The number of flights indicates the number of screw flights and thus screw channels. The number of screw flights usually corresponds to the number of screw channels.

A “sealing area” refers to an area of a screw flight which has a flight distance over an axial length of at least half the screw diameter that corresponds to the screw clearance, preferably over an axial length of at least the screw diameter, particularly preferably over an axial length of at least 1 , 5 times the screw diameter has a land spacing that corresponds to the screw clearance.

“Corresponds to the worm clearance” means that the web spacing can deviate from the worm clearance within the framework of the usual manufacturing tolerances.

If the flight height along the screw flight is different, the screw flight height of the sealing area results from the arithmetic mean.

If the basic distances between the two surrounding screw channels are different in at least one axial position, the screw flight heights and the basic distances of the sealing area are each averaged separately for both surrounding screw channels.

A “flow area” refers to an area of a screw flight which has a flight distance over an axial length of at least half the screw diameter that is greater than the screw clearance, preferably over an axial length of minimally the screw diameter, particularly preferably over an axial length of minimally 1.5 times the screw diameter has a land spacing that is greater than the screw clearance.

The web spacing in the flow area is preferably significantly greater than the screw play, preferably at least twice as large as the screw play, particularly preferably at least 3 times as great as the screw play.

Processing material can preferably flow over the screw flight in a flow region, particularly preferably processing material in a molten state.

In the flow area, the screw flight height at an axial position corresponds to the basic distance of the surrounding screw channels at the axial position minus the flight distance at the axial position. If the basic distance from at least one of the surrounding screw channels and / or the flight distance varies along the flow area, the screw flight height and the basic distance of the flow area each result from the arithmetic mean.

If the basic distances between the two surrounding screw channels are different in at least one axial position, the screw flight heights and the basic distances of the flow area are averaged separately for both surrounding screw channels. A "height-limited flow area" is present when a flow area is present on a screw flight which has a flight height of at least 30% of the basic distance at the point to both surrounding screw channels, preferably a flight height of at least 40%, particularly preferably a flight height of at least 45 % of the basic distance present at the point and the screw flight height to both surrounding screw channels of a maximum of 70% of the basic distance present at the point, preferably a screw flight height of a maximum of 60%, particularly preferably a screw flight height of a maximum of 55% of the basic distance present at the point having.

A "narrow flow area" is present when a flow area is present on a screw flight which has a flight height of more than 70% of the basic distance at the point of at least one surrounding screw channel, preferably a flight height of at least 80%, particularly preferably a flight height of has a minimum of 85% of the basic distance present at the point.

A narrow flow area thus differs from a height-limited flow area through the height of the screw flight and the resulting flight distance.

A screw web with a narrow flow area is preferably a so-called barrier web, which is usually arranged in a barrier zone of an extruder between the inlet channel, also called the solids channel and the outlet channel, also called the melt channel, so that the processing material that is in the vicinity the cylinder wall is at least partially guided by the rotary movement of the screw from the inlet channel over the barrier web to the outlet channel. The web spacing in the flow area of a barrier web is usually between 0.4 mm and 1.5 mm. The small values are usually more in extruders with a small screw diameter and the larger values in extruders with a large screw diameter. There is also at least one main walkway in a barrier zone.

A screw flight with a narrow flow area is preferably a so-called shear flight, which is usually used in a shear part of an extruder between the inlet channel and the outlet channel. The web spacing in the flow area of a shear web is usually between 0.4 mm and 1.5 mm. The small values are usually more in extruders with a small screw diameter and the larger values in extruders with a large screw diameter.

A "mixing wall section" refers to a section of a screw flight which, over an axial length of less than half a screw diameter, has a screw flight height of more than 75% of the basic distance, preferably more than 85% of the basic distance, preferably more than the two surrounding screw channels than 90% of the basic distance. The worm flight particularly preferably has a flight spacing which corresponds to the screw play. Lies on one axial position If the screw flight has a sealing area, a mixed wall section is not present there at the same time. In other words, long sealing areas are not divided by short mixing wall sections.

The axial length of a mixing wall section preferably corresponds to a maximum of one third of the screw diameter, particularly preferably a maximum of one quarter of the screw diameter.

If the basic distance from at least one of the surrounding screw channels and / or the flight distance varies along the mixing wall section, the screw flight height and the basic distance of the mixing wall section result from the arithmetic mean.

If the basic distances between the two surrounding screw channels are different in at least one axial position, the screw flight heights and the basic distances of the mixing wall section are each averaged separately for both surrounding screw channels.

A "mixing gap section" refers to a section of a screw flight which has a screw flight height of a maximum of 75% of the basic distance over an axial length of less than half a screw diameter to the two surrounding screw channels. If there is a flow area at an axial position on a screw flight, a mixing gap section is not present there at the same time. In other words, long flow areas are not divided by short mixing gap sections.

The axial length of a mixing gap section preferably corresponds to a maximum of one third of the screw diameter, particularly preferably a maximum of one quarter of the screw diameter.

In a preferred embodiment, a section that has an axial length that is smaller than half the screw diameter, preferably has an axial length that corresponds to a maximum of one third of the screw diameter, particularly preferably has an axial length that corresponds to a maximum of a quarter of the screw diameter and which is not a mixing wall section is a mixing gap section.

If the basic distance from at least one of the surrounding screw channels and / or the flight distance varies along the mixing gap section, the screw flight height and the basic distance of the mixing gap section result from the arithmetic mean.

If the basic distances between the two surrounding screw channels are different in at least one axial position, the screw flight heights and the basic distances of the mixing gap section are each averaged separately for both surrounding screw channels.

A “gap wall area” refers to the area of a screw flight in which only alternating mixed gap sections and mixed wall sections are present. If there is a sealing area in front of the gap-wall area, the gap-wall area begins with the first mixed gap section. If there is a flow area in front of the gap-wall area, the gap-wall area begins with the first mixed wall section. If there is a sealing area after the gap-wall area, the gap-wall area ends with the last one Mixed gap section. If a screw flight begins with a mixed gap section or a mixed wall section, the gap-wall area also begins at this point. If a screw flight ends with a mixed gap section or a mixed wall section, the gap-wall area also ends at this point.

A "height-limited gap-wall area" denotes the area of a screw flight on which a gap-wall area has at least two mixing gap sections, preferably at least 4, preferably at least 6, particularly preferably at least 8 mixing gap sections, with at least 50% of the mixing gap sections, preferably at least 70%, particularly preferably at least 90% of the mixing gap sections to the two surrounding screw channels have a screw flight height of at least 30% of the basic distance, preferably a minimum of 40%, particularly preferably to both surrounding screw channels have a screw flight height of at least 45% of the basic distance and to both surrounding screw channels have a screw flight height of a maximum of 70% of the basic distance, preferably of a maximum of 60%, particularly preferably a screw flight height of a maximum of 55% of the basic distance to both surrounding screw channels.

In a preferred embodiment, at least 30% of the mixing wall sections, preferably at least 50%, preferably at least 70%, particularly preferably at least 90% of the mixing wall sections are at a distance from the cylinder wall that corresponds to the screw play.

A “mixing zone” denotes that part of a screw in which at least one gap-wall area is present on at least one at least partially helical, preferably largely helical, particularly preferably exclusively helical around the screw and / or on at least one at least partially helical , preferably largely helical, particularly preferably exclusively helical, screw web running around the screw at least one flow area is present.

Flow areas and / or gap-wall areas can be present on the same screw flight or different screw flights.

If in an axial part of the screw there is a gap-wall area on exactly one screw flight, the axial part begins with the beginning of the gap-wall area and ends with the end of the gap-wall area, and lies in that axial part no flow area before and directly before and directly after the axial part if there is no gap-wall area and no flow area, the mixing zone begins in the axial direction with the beginning of the axial part and ends in the axial direction with the end of the axial part.

If in an axial part of the screw there is a flow area on exactly one screw flight, the axial part begins with the beginning of the flow area and ends with the end of the flow area, and there is no gap in the axial part. Wall area in front of and directly in front of and directly after the axial part, if there is no gap wall area and no flow area, the mixing zone begins in the axial direction with the beginning of the axial part and ends in the axial direction with the end of the axial part.

If in an axial part of the screw there are several gap-wall areas or several flow areas on exactly one screw flight, between which there are sealing areas on the screw flight, there are correspondingly several mixing zones in the axial part of the screw.

If there are flow areas and gap-wall areas between which there are sealing areas in an axial part of the screw only on one screw flight, there are correspondingly several mixing zones in the axial part of the screw.

If, in an axial part of the screw, there are flow areas and gap-wall areas that are directly one after the other on only one screw flight, these areas belong to the same mixing zone and the mixing zone begins with the beginning of the first area in the axial direction and ends with the end of the last area in the axial direction.

If there are several screw flights in an axial part of the screw, which have at least one gap-wall area and / or at least one flow area and the areas lie directly one after the other in the axial direction or if these areas of different screw flights overlap in the axial direction, the associated one begins Mixing zone with the beginning of the first area in the axial direction and ends with the end of the last area in the axial direction.

If there are several screw flights in an axial part of the screw which have gap-wall areas and / or flow areas and there are axial positions in which there are sealing areas, the respective mixing zone begins and / or ends at the axial position at which on all of them the screw flights present in the axial position.

The generic term mixing zone refers exclusively to the following versions: a) A "vortex mixing zone" refers to the mixing zone of a screw in which all existing screw flights only have gap-wall areas. b) A "flow mixing zone" refers to the mixing zone of a screw in which all existing screw flights only have flow areas. c) A “barrier mixing zone” refers to the mixing zone of a screw in which at least one screw flight has a flow area and at least one screw flight has a sealing area and no screw flight has a gap-wall area. d) A “vortex barrier mixing zone” refers to the mixing zone of a screw in which at least one screw flight has a gap-wall area and at least one screw flight has a sealing area and at least one screw flight has a flow area. e) A “vortex-tight mixing zone” refers to the mixing zone of a screw in which at least one screw flight has a gap-wall area and at least one screw flight has a sealing area and no screw flight has a flow area. f) A “vortex-flow mixing zone” refers to the mixing zone of a screw in which at least one screw flight has a gap-wall area and at least one screw flight has a flow area and no screw flight has a sealing area

A “homogenization zone” is the axial zone of the extruder in which at least one screw of the extruder has any mixing zone and / or any mixing part according to the prior art and / or any desired shear part according to the present specification Has technology. No, one or more homogenization zones can be present in an extruder.

In the prior art, a distinction is usually made between barrier zones and homogenization zones. However, the transition from the barricade zone and the homogenization zone can be fluid or unclear and needs to be defined. In the context of the present document, a zone of the screw is regarded as a “barrier zone” if the zone has at least one screw flight with a narrow flow area and at least one screw flight with a sealing area. A barrier zone is exclusively also a homogenization zone or part of a homogenization zone if a) there is already another barrier zone in front of the barrier zone. In other words, if there are several barrier zones on one screw, the first barrier zone is exclusively considered a barrier zone and the others as barrier zones and homogenization zones. b) the barrier zone has a homogenization area. A “homogenization area” has at least an axial length of 20% of the axial length of the barrier zone and has at least one web with a gap-wall area and / or a web with a height-limited flow area.

For example, a screw that has exactly one barrier zone, the barrier zone not having a homogenization area, additionally requires exactly two homogenization zones in order to have exactly two homogenization zones.

The “main feed zone” is the axial zone of the extruder, in which usually most of the meltable or melted components of the processing material or all of the processing material is fed to the extruder. For this purpose, an opening, such as a bore, is located in this zone in the screw cylinder. The shape of the opening in the axial direction defines the axial length of the main feed zone. There is exactly one main feed zone in an extruder.

A “secondary feed zone” is the axial zone of the extruder in which part of the processing material and / or additional materials, e.g. so-called additives or Fillers are fed to the extruder. For this purpose, an opening, such as a bore, is located in this zone in the screw cylinder. The shape of the opening in the axial direction defines the axial length of the secondary feed zone. No, one or more secondary feed zones can be present in an extruder.

The “main discharge zone” is the axial zone through which at least part of the processing material, preferably at least a large part, particularly preferably all of the processing material, is discharged for further processing, e.g. to a shaping extrusion tool or injection molding tool. The main discharge zone is usually at the end of the extruder, but in special cases it can also be an axial zone of the extruder in which there is still at least one screw. If the main discharge zone is at the end of the extruder, it begins directly after the end of the screw, which ends last in the axial direction, and it ends at the end of the extruder. If there is at least one screw in the extruder, which at the end is partly located in a component following the extruder, such as a screen changer, the main discharge zone begins and ends with the end of the last screw. If the main discharge zone is in an axial part of the extruder in which there is still at least one screw, there is an opening in the screw cylinder for the purpose of discharge, e.g. a bore.

The shape of the opening in the axial direction defines the axial length of the main discharge zone. There is exactly one main discharge zone in an extruder.

A “secondary discharge zone” is the axial zone of the extruder in which at least one screw is still present and in which part of the processing material and / or at least part of at least one component of the processing material is discharged from the extruder. This can be solid, liquid, molten and / or gaseous parts of at least one component of the processing material. For this purpose there is an opening in this zone in the cylinder, such as a bore. The shape of the opening in the axial direction defines the area of the secondary discharge zone. No, one or more secondary discharge zones can be present in an extruder.

A “process zone” is the zone of a screw in which the screw usually comes into contact with the processing material in order to discharge it. If the screw has a return thread, a toothing or a screw shaft, these zones do not belong to the process zone of the screw, even if they come into contact with the processing material, unless it is expressly mentioned that these zones belong to the process zone.

All of the following aspects are based on the same inventive idea of using the mixing zones described above in advantageous embodiments in order to achieve the task described above.

According to a first aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, at least one screw having at least two homogenization zones (HZ1 and HZ2), wherein the homogenization zone HZ1 is a mixing zone (MZ1) which has at least partially at least one height-limited gap-wall area on at least one screw flight and / or at least partially has at least one height-limited flow area on a screw flight and the homogenization zone HZ2 has at least the same number of screw flights as the homogenization zone HZ1, preferably has more screw flights, particularly preferably an integral multiple of the screw flights of the homogenization zone HZ1.

The homogenization zone HZ1 is preferably located in front of the homogenization zone HZ2.

In an advantageous embodiment, the mixing zone MZ1 is a vortex-tight mixing zone or a barrier mixing zone or a vortex mixing zone, with at least one screw flight with at least one height-limited gap-wall area (LWB1), the sum of the lengths of all mixing wall sections of the height-limited gap-wall area LWB1 along the screw flight is at least 1.2 times as large, preferably at least 1.5 times as large, particularly preferably at least 2 times as large as the sum of the lengths of all mixing gap sections of the gap Wall area LWB1 along the screw flight or a vortex barrier mixing zone.

The homogenization zone HZ2 is preferably a mixing zone (MZ2) which particularly preferably has at least partially at least one height-limited gap-wall area and / or at least one height-limited flow area on at least one screw flight.

In an advantageous embodiment, the mixing zone MZ2 is a vortex mixing zone or a vortex-tight mixing zone, preferably at least 50% of the screw flights of the vortex-tight mixing zone, preferably at least 70% of the screw flights, particularly preferably at least 90% of the screw flights to less than 50%, preferably less than 40%, particularly preferably less than 30% of their length have a sealing area.

The design and arrangement of the homogenization zones according to the invention can achieve improved conveyance of the processing material and an improved pressure profile along the screw and, in addition, good homogenization can be achieved. In particular, but not exclusively, parts of screws according to the prior art, consisting of customary metering zones and mixing parts, can be economically replaced with regard to similar conveyance of the processing material and similar pressure build-up while at the same time improving the homogenization performance.

The homogenization zone HZ1 is preferably located in front of the homogenization zone HZ2 and there is at least one continuous screw flight from the beginning of the homogenization zone HZ1 to the end of the homogenization zone HZ2. Particularly preferably, the Screw web at least one height-limited gap-wall area and a sealing area. The screw flight is particularly preferably already present before the start of the homogenization zone HZ1. Particularly preferably, the screw flight is also present after the end of the homogenization zone HZ2.

In an advantageous embodiment, the maximum basic distance in the homogenization zone HZ2 is smaller than the minimum basic distance in the homogenization zone HZ1. The homogenization zone HZ2 preferably has a maximum of 75%, particularly preferably a maximum of 50% of the minimum basic spacing of the homogenization zone HZ1.

In an advantageous embodiment, the homogenization zone HZ2 has a different pitch than the homogenization zone HZ1; the pitch of the homogenization zone HZ2 is preferably greater than the pitch of the homogenization zone HZ1. In an alternative embodiment, the pitch of the homogenization zone HZ2 is smaller than the pitch of the homogenization zone HZ1.

In an advantageous embodiment, the length of the homogenization zone HZ1 is greater than the length of the homogenization zone HZ2, preferably the homogenization zone HZ1 is at least 1.5 times as long as the homogenization zone HZ2, particularly preferably at least 2 times as long.

In an alternative embodiment, the homogenization zone HZ2 is located in front of the homogenization zone HZ1 and from the beginning of the homogenization zone HZ2 to the end of the homogenization zone HZ1 there is at least one continuous screw flight. The screw flight particularly preferably has at least one height-limited gap-wall area and a sealing area. Particularly preferably, the screw flight is already present before the start of the homogenization zone HZ2. Particularly preferably, the screw flight is also present after the end of the homogenization zone HZ1.

According to a second aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, at least one screw having at least one screw flight on which at least one height-limited gap-wall area is at least partially and has at least one screw flight, on which at least partially at least one height-limited flow area is present.

There is preferably at least one height-limited flow area after at least one height-limited gap-wall area.

Tests on several prototypes have shown that this type of design leads to an improved pressure profile along the screw and, at the same time, to an improved homogeneity of the processing material.

In an advantageous embodiment, the same number of screw flights are present in at least 60% of the length of the process zone of the screw, preferably in at least 80%, in particular preferably in at least 90%. The worm preferably has a number of flights of at least four.

In an advantageous embodiment, at least one axial part of the screw has more screw flights with a height-limited gap-wall area than screw flights with a height-limited flow area. Preferably, there is no screw flight with a height-limited flow area in an axial part of the screw.

In an advantageous embodiment, at least one axial part of the screw has more screw flights with a height-limited flow area than screw flights with a height-limited gap-wall area. In an axial part of the screw there is preferably no screw flight with a height-limited gap-wall area.

In an advantageous embodiment, the area (GB1) comprises the areas of all mixing zones which have at least one height-limited gap-wall area and / or at least one height-limited flow area, with at least 50% of the area GB1 having the same number of flights at all axial positions, particularly preferably at least 75% of the area has the same number of turns at all axial positions, particularly preferably at least 90% of the area has the same number of turns at all axial positions.

The screw preferably has at least one vortex-barrier mixing zone.

The screw preferably has at least one barrier mixing zone.

The screw preferably has at least one vortex mixing zone.

The screw preferably has at least one vortex-sealing mixing zone.

The screw preferably has at least one barrier mixing zone and at least one eddy-tight mixing zone.

The screw preferably has at least one barrier mixing zone and at least one vortex mixing zone.

It should be expressly pointed out that the subject matter of the second aspect can advantageously be combined with the subject matter of the first aspect of the invention, either individually or cumulatively in any combination, provided that the subject matter of the aspects is not technically excluded for the person skilled in the art.

According to a third aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, at least one screw flight having a height-limited gap-wall area and at least one screw flight a sealing area in at least one axial part (AT1) of the screw and in at least one other axial part (AT2) of the screw at least one screw flight has a height-limited gap-wall area and no screw flight has a sealing area. In an advantageous embodiment, the axial parts AT1 and AT2 of the screw each have a length of at least 0.5 times the screw diameter, preferably a length of at least 1 times the screw diameter, particularly preferably a length of at least 1.5 times the screw diameter.

Tests on several prototypes have shown that this type of design leads to an improved pressure profile along the screw and, at the same time, to an improved homogeneity of the processing material. The axial parts with a sealing area increase the conveying effect while at the same time improving the homogeneity within the screw channels and the axial parts without a sealing area increase the homogeneity in the circumferential direction.

In an advantageous embodiment, the same number of screw flights are present in at least 60% of the sum of the lengths of all homogenization zones of the screw, preferably in at least 80%, particularly preferably in at least 90%. The worm preferably has a number of flights of at least four.

In an advantageous embodiment, the same number of screw flights are present in at least 60% of the sum of the lengths of all homogenization zones of the screw, which have at least one height-limited gap-wall area, preferably in at least 80%, particularly preferably in at least 90%. The worm preferably has a number of flights of at least four.

In an advantageous embodiment, the same number of screw flights are present in at least 60% of the length of the process zone of the screw, preferably in at least 80%, particularly preferably in at least 90%. The worm preferably has a number of flights of at least four.

The axial parts AT1 and AT2 are preferably located directly one after the other.

In an alternative embodiment, there is at least one area between the axial parts AT1 and AT2 in which all the screw flights exclusively have sealing areas.

In an advantageous embodiment, the axial parts AT1 and AT2 are in the same mixing zone. In an alternative embodiment, the axial parts AT1 and AT2 are in different mixing zones.

The screw preferably has at least one vortex mixing zone.

The screw preferably has at least one vortex-sealing mixing zone.

The screw preferably has at least one vortex-tight mixing zone and at least one vortex mixing zone.

It should be expressly pointed out that the subject matter of the third aspect can advantageously be combined with the subject matter of the first aspect of the invention, specifically individually or cumulatively in any combination, provided that subjects of the aspects are not technically excluded for the person skilled in the art.

According to a fourth aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, at least one screw having at least one mixing zone which has at least one screw flight which at least partially has at least one height-limited gap-wall area, wherein at least three, preferably at least four, particularly preferably at least five, mixing gap sections in the mixing zone have the same screw flight height and the same length along the respective screw flight.

With "same length" and "same screw flight height" it is meant that the lengths and heights are the same within the scope of the usual manufacturing tolerances.

At least one screw flight is preferably present in a vortex-mixing zone or a vortex-tight mixing zone or a vortex-barrier mixing zone.

In an advantageous embodiment, there are at least three, preferably at least four, particularly preferably at least five, mixing gap sections along precisely one helix which runs around the screw with precisely one pitch.

In this way, the gap-wall areas can be produced more economically.

The at least three, preferably at least four, particularly preferably at least five, mixing gap sections are preferably present on one screw flight, each separated by exactly one mixing wall section, with further mixing gap sections and mixing wall sections being able to be present on any further webs that may be present.

At least two groups (MLA1, MLA2) of mixed gap sections are preferably present, each of which has at least three, preferably at least four, particularly preferably at least five mixed gap sections, the mixed gap sections of group MLA1 lying along exactly one helix which has exactly one pitch (S1) runs around the screw and the mixing gap sections of the group MLA2 lie along a helix that runs around the screw with exactly one pitch (S2), the pitch S2 being different from the pitch S1.

Tests on several prototypes have shown that the relationship between vortex formation and circumferential mixing can be adjusted in this way, and thus this type of design leads to improved conveyance of the processing material and an improved pressure profile along the screw while at the same time improving the homogeneity of the processing material extremely economical production of this design is still possible.

It should be expressly pointed out that the subject matter of the fourth aspect can advantageously be combined with the subject matter of the above aspects of the invention, specifically individually or cumulatively in any desired combination, provided that subjects of the aspects are not technically excluded for the person skilled in the art. According to a fifth aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, at least one screw having at least one mixing zone which has at least one screw flight which has at least two mixing gap sections with different lengths along the screw flight, which are located in at least one height-limited gap-wall area and / or has at least two mixing wall sections with different lengths along the screw flight, which are located in at least one height-limited gap-wall area.

The differences in length along the screw flight of mixed gap sections and mixed wall sections that are located directly at the beginning or at the end of the respective gap-wall area are not taken into account.

The screw flight is preferably in a vortex-mixing zone or vortex-tight mixing zone or vortex-barrier mixing zone.

The at least two mixing wall sections are preferably present together in a mixing zone.

The at least two mixing gap sections are preferably present together in a mixing zone.

There are preferably several mixing zones, the at least two mixing wall sections being present in different mixing zones and / or the at least two mixing gap sections being present in different mixing zones.

The differences in length preferably arise from the fact that at least two groups (MLA3, MLA4) of mixed gap sections are present, each of which has at least three, preferably at least four, particularly preferably at least five, mixed gap sections, the mixed gap sections of group MLA3 lying along a helix that has exactly one Pitch (S3) runs around the screw and the mixing gap sections of the group MLA4 lie along a helix that runs around the screw with exactly one pitch (S4), the pitch S4 being different from the pitch S3. The gradients, which are different, result, provided the length of the mixing gap sections remains constant, mixing wall sections with different lengths along the respective associated screw flight.

Tests on several prototypes have shown that this type of design leads to improved conveyance of the processing material and an improved pressure profile along the screw and, at the same time, to improved homogeneity of the processing material, with this design being extremely economical to manufacture.

It should be expressly pointed out that the subject matter of the fifth aspect can advantageously be combined with the subject matter of the above aspects of the invention, namely individually or cumulatively in any combination, provided that the subjects of the aspects are not technically excluded for the person skilled in the art.

According to a sixth aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, the screw having at least one mixing zone which has at least one screw flight, the at least partially at least one height-limited gap-wall area and / or at least partially has at least one height-limited flow area, with a higher number of flights in at least one axial part (AT4) of the mixing zone than in another axial part (AT3) of the mixing zone.

An integral multiple of the number of turns of the axial part AT3 is preferably present in the axial part AT4.

The axial part AT4 is preferably located after, particularly preferably directly after the axial part AT3.

The axial part AT3 is preferably located after, particularly preferably directly after the axial part AT4.

The axial part AT3 preferably has at least partially a different basic distance than the axial part AT4.

The axial part AT3 preferably has at least partially a different pitch than the axial part AT4.

Tests on several prototypes have shown that this type of execution leads to an improved setting of the relationship between conveyance and homogeneity of the processing material.

It should be expressly pointed out that the subject matter of the sixth aspect can advantageously be combined with the subject matter of the above aspects of the invention, either individually or cumulatively in any combination, provided that the subject matter of the aspects is not technically excluded for the person skilled in the art.

According to a seventh aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, the screw having at least one mixing zone with at least one screw channel, the screw channel at least partially on at least one side having a screw flight with at least one height-limited gap Wall area and / or at least one height-limited flow area, the quotient of the maximum base distance over the maximum width of the screw channel in the area of the mixing zone over an axial length of at least 0.5 times the screw diameter, preferably at least 1 times the screw diameter , particularly preferably over an axial length of at least 1.5 times the screw diameter at each axial position is a maximum of 1.4, preferably a maximum of 1.2, particularly preferably a maximum of 1.1 and is a minimum of 0.1, preferably a minimum of 0.25, particularly preferably a minimum of 0.3.

In an advantageous embodiment, at least 50%, preferably at least 70%, particularly preferably at least 90% of the screw channels of the mixing zone at least partially on one side, preferably at least partially on both sides, have a screw flight with at least one height-limited gap-wall area and / or at least a height-limited flow area, the quotient of the maximum basic distance over the maximum width of the respective screw channel in the area of the mixing zone over an axial length of at least 0.5 times the screw diameter, preferably at least 1 times the screw diameter, particularly preferably over an axial length of at least 1.5 times the screw diameter at each axial position is a maximum of 1.4, preferably a maximum of 1.2, particularly preferably a maximum of 1.1 and a minimum of 0.1, preferably a minimum of 0.25, particularly preferably a minimum of 0 , 3 is.

Tests on several prototypes have shown that this type of design increases the formation of eddies and leads to an improved conveyance of the processing material and an improved pressure profile along the screw and, at the same time, an improved homogeneity of the processing material.

It should be expressly pointed out that the subject matter of the seventh aspect can advantageously be combined with the subject matter of the above aspects of the invention, specifically individually or cumulatively in any combination, provided that subjects of the aspects are not technically excluded for the person skilled in the art.

According to an eighth aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, the extruder having at least one secondary feed zone and the screw having at least one screw flight which at least partially has at least one height-limited gap-wall area and / or at least partially has at least one height-limited flow area, at least part of the height-limited gap-wall area and / or at least part of the height-limited flow area lying after the secondary feed zone.

At least part of at least one vortex-tight mixing zone is preferably present after the secondary feed zone.

At least part of at least one barrier mixing zone is preferably located downstream of the secondary feed zone.

At least part of at least one vortex mixing zone is preferably present after the secondary feed zone.

At least part of at least one vortex barrier mixing zone is preferably located downstream of the secondary feed zone. Particularly preferably, there is at least one vortex mixing zone after a vortex-tight mixing zone and / or after a barrier mixing zone.

A component of the processing material is preferably at least one type of fiber, particularly preferably glass fibers and / or carbon fibers.

At least some of the fibers are preferably fed to the extruder via the secondary feed zone.

Preferably at least some of the fibers, preferably at least 60% of the fibers, particularly preferably at least 80% of the fibers, are heated before they enter the cylinder in the secondary feed zone through an opening. At least some of the fibers are preferably heated to at least 70% of the weight-averaged melting temperature of the processing material, preferably to at least 80%, particularly preferably to at least 90%.

The unit for temperature is ° C. In other words: If the weight-average melting temperature of the processing material is 200 ° C, then 80% of this melting temperature is 160 ° C.

In an advantageous embodiment, the extruder is part of an injection molding device and the extruder introduces the processing material in a time-discrete manner into at least two pistons, which each feed the processing material to at least one injection molding tool in a time-discrete manner. During at least two piston filling cycles, preferably for at least 4 piston cycles, particularly preferably for at least 10 piston cycles, in which all pistons present are filled in a time-discrete manner, the speed of at least one screw of the extruder remains constant. In this context, constant means that the speed remains constant within the framework of a regulation, i.e. is still considered constant if the speed fluctuates by a maximum of 1-2% of the mean value due to possible control deviations.

Tests on several prototypes have shown that this type of design leads to an improved conveyance of the processing material and an improved pressure distribution along the screw and, at the same time, to an improved homogeneity of the processing material and the components supplied through the secondary supply zone.

It should be expressly pointed out that the subject matter of the eighth aspect can advantageously be combined with the subject matter of the above aspects of the invention, either individually or cumulatively in any combination, provided that subjects of the aspects are not technically excluded for the person skilled in the art.

According to a ninth aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, wherein the extruder has at least one secondary feed zone and at least part of at least one homogenization zone is located between the end of the first secondary feed zone and the beginning of the main discharge zone, wherein the areas of all parts of all Homogenization zones that lie between the end of the first secondary feed zone and the start of the main discharge zone are combined in group (HAR1), the sum (AL1) of the axial lengths of the areas in group HAR1 being greater than 50% of the axial length (AL2) of the area from the end of the first secondary feed zone to the start of the main discharge zone, preferably greater than 65%, particularly preferably greater than 80% of the axial length AL2.

It should be expressly pointed out that the regions of the group HAR1, viewed in the axial direction, can, but do not have to be, adjacent. In other words, between individual areas of homogenization zones of group HAR1, parts of the extruder can also be present in which there is no homogenization zone on any screw.

At least one mixing zone is preferably present in at least one area of a homogenization zone of group HAR1, which has at least partially at least one height-limited gap-wall area and / or at least one height-limited flow area on at least one screw flight.

A sealing area is preferably at least partially present on at least one screw flight, particularly preferably on precisely one screw flight, of the areas of group HAR1.

The sum of the axial lengths on which a sealing area is present in the areas of group HAR1 on at least one screw flight, particularly preferably on exactly one screw flight, is at least 50%, particularly preferably at least 60%, particularly preferably at least 70% of the axial length AL1. There can be one sealing area or there can be several sealing areas in the axial direction that are interrupted by other areas.

At least part of the screw is preferably multi-threaded and there is at least one sealing area on several screw flights in the areas of group HAR1, parts of the sealing areas on several screw flights not having to be in the same axial position, but being able to be. In other words, the sealing areas that are present on different screw flights can overlap axially, but do not have to.

The sum of the axial lengths on which at least one gap-wall area, particularly preferably at least one height-limited gap-wall area, is present in the areas of group HAR1 on at least one screw flight is preferred, at least 50%, particularly preferably at least 60%, particularly preferably at least 70%, particularly preferably at least 80% of the axial length AL1.

The sum of the axial lengths on those in the areas of group HAR1 on at least one screw flight is preferably at least one flow area, particularly preferred at least one height-limited flow area is present, at least 50%, particularly preferably at least 60%, particularly preferably at least 70% of the axial length AL1.

Tests on several prototypes have shown that this type of design leads to improved conveyance of the processing material and an improved pressure profile along the screw and, at the same time, to improved homogeneity of the processing material and the constituents supplied through the secondary supply zone.

It should be expressly pointed out that the subject matter of the ninth aspect can advantageously be combined with the subject matter of the above aspects of the invention, either individually or cumulatively in any combination, provided that the subject matter of the aspects is not technically excluded for the person skilled in the art.

According to a tenth aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, the extruder having at least one secondary discharge zone and the screw having at least one mixing zone which has at least one screw flight which at least partially has at least one height-limited gap Wall area and / or at least partially has at least one height-limited flow area, the area of at least one mixing zone at least partially superimposed on the area of the secondary discharge zone.

At least one mixing zone is preferably a vortex-tight mixing zone.

At least one mixing zone is preferably a barrier mixing zone.

At least one mixing zone is preferably a vortex mixing zone.

The screw is preferably at least partially multi-threaded within at least one mixing zone.

Tests on several prototypes have shown that this type of design achieves better removal of discharge products and leads to improved conveyance and homogenization of the processing material along the screw.

It should be expressly pointed out that the subject matter of the tenth aspect can advantageously be combined with the subject matter of the above aspects of the invention, specifically individually or cumulatively in any combination, provided that the subject matter of the aspects is not technically excluded for the person skilled in the art.

According to an eleventh aspect of the invention, the above-mentioned object is achieved by an extruder with at least one screw for processing a processing material, the screw particularly preferably dissolving in at least one axial position, preferably on an axial part of the screw with an axial length of at least 1 screw diameter an axial part of the screw with an axial length of at least 2 screw diameters has at least one screw flight (S6) which has a height-limited gap-wall area or a height-limited flow area and at least one further screw flight (S7) which has a narrow flow area and preferably has at least one screw flight (S5) which has a sealing area .

In other words, the screw flights S6, S7 and S5 are distributed together in at least one axial position on the circumference of the screw. Preferably, the screw flights S6, S7 and S5 are present together on an axial part of the screw with an axial length of at least 1 screw diameter distributed around the circumference of the screw, particularly preferably on an axial part of the screw with an axial length of at least 2 screw diameters.

Tests on several prototypes have shown that this design leads to a better pressure curve along the screw and a better homogeneity of the processing material and at the same time enables a shorter and thus more economical design.

In a preferred embodiment, the axial position or the axial part lies in a mixing zone, the mixing zone being at least partially superimposed with a barrier zone and the mixing zone beginning with the beginning of the barrier web of the barrier zone or before the beginning of the barrier web of the barrier zone.

At least part of the screw flight S7 is preferably at least partly the barrier flight of the barrier zone.

At least part of the screw flight S6 preferably lies at least partially in the outlet channel of the barrier zone.

At least part of the screw flight S6 preferably lies at least partially in the inlet channel of the barrier zone.

At least part of the screw flight S5 is preferably at least partly the so-called main flight of the barrier zone.

In an advantageous embodiment, in a multi-thread part of the mixing zone, at least 50% of the axial length of the mixing zone, at all axial positions of the screw flights S6, has the same pitch as the screw flight S5, particularly preferably at least 75% of the axial length of the mixing zone, especially preferably over at least 90% of the axial length of the mixing zone.

After the end of the barrier zone there is preferably at least one height-limited gap-wall area and / or a height-limited flow area on the screw flight S5, particularly preferably the axial length of the height-limited gap-wall area and / or the height-limited flow area is at least 2 screw diameters.

The mixing zone preferably ends in the axial direction only after the end of the barrier zone. In an alternative embodiment, the mixing zone ends with the end of the barrier web of the barrier zone or after the end of the barrier web of the barrier zone.

In an advantageous embodiment, the screw flight S5 has at least one mixed gap section after the sealing area, preferably at least one gap-wall area, particularly preferably at least one height-limited gap-wall area.

In an advantageous embodiment, the screw flight S5 has at least one mixed gap section in front of the sealing area, preferably at least one gap-wall area, particularly preferably at least one height-limited gap-wall area.

The screw flight S7 preferably has a different pitch at the axial position and / or the axial parts than the screw flight S5, particularly preferably the direction of rotation of the screw flight S7 around the screw is opposite to the direction of rotation of the screw flight S5 around the screw.

The mixing zone is preferably a vortex-tight mixing zone.

The mixing zone is preferably a barrier mixing zone.

The mixing zone is preferably a vortex barrier mixing zone.

It should be expressly pointed out that the subject matter of the eleventh aspect can advantageously be combined with the subject matter of the above aspects of the invention, either individually or in any combination, provided that the subject matter of the aspects is not technically excluded for the person skilled in the art.

The following statements can be combined advantageously individually or in any combination cumulatively with one or more of the preceding aspects of the invention, provided that subjects of the aspects and / or statements are not technically excluded for the person skilled in the art.

At least one screw is preferably multi-threaded at least in part of the area of at least one mixing zone.

The extruder is preferably part of an injection molding device.

In an advantageous embodiment, in a multi-flight part of a mixing zone, all screw flights in all axial positions have the same pitch over at least 50% of the axial length of the mixing zone, particularly preferably over at least 75% of the axial length of the mixing zone, particularly preferably at least 90% the axial length of the mixing zone.

The processing material is preferably fed to the extruder in the main feed zone, at least for the most part, in melt form under pressure.

In an advantageous embodiment, the cylinder wall temperature is at least 25% of the length of the second half of the extruder viewed in the axial direction below the melting temperature of the processing material, preferably at least 50% of the length of the second half of the extruder, particularly preferably at least 75%. In an advantageous embodiment, at least one axial part (AT2) in at least one mixing zone has an integral multiple of screw flights of at least one other axial part (AT1). The axial part AT2 is preferably located after the axial part AT1 in the axial direction. Alternatively, the axial part AT1 lies in the axial direction after the axial part AT2.

In an advantageous embodiment, the sum of the lengths of all homogenization zones lying on a screw is a minimum of 50% of the length of the process zone of the screw, preferably a minimum of 60%, preferably a minimum of 70%, particularly preferably a minimum of 80% of the length of the process zone of the screw.

The area of at least one mixing zone preferably overlaps at least partially with the area of a secondary discharge zone. The mixing zone preferably has at least one web with at least one height-limited gap-wall area and / or at least one web with at least one height-limited flow area. The mixing zone preferably begins before the secondary discharge zone.

The entire area of at least one secondary discharge zone is preferably superimposed with at least part of the area of a mixing zone. The mixing zone preferably has at least one web with at least one height-limited gap-wall area and / or at least one web with at least one height-limited flow area. This inventive embodiment can advantageously improve the performance of a degassing zone, for example, through the improved homogenization with subsequent pressure build-up.

The area of at least one mixing zone preferably overlaps at least partially with the area of a secondary feed zone. The mixing zone preferably has at least one web with at least one height-limited gap-wall area and / or at least one web with at least one height-limited flow area. The length of the mixing zone after the secondary feed zone is preferably at least 2 screw diameters, particularly preferably at least 3 screw diameters. The mixing zone preferably begins before the secondary feed zone. There is preferably at least one axial position in the area of the secondary feed zone at which there is no sealing area and no mixing wall section on any of the screw flights. Particularly preferably, there is no sealing area and no mixing wall section on all screw flights in the area of the secondary feed zone.

Preferably, at least one screw channel at least partially to the screw flight with a height-limited gap-wall area and / or a height-limited flow area has a radius that is greater than 30% of the basic distance in each case at the axial position in the screw channel, preferably greater than 35 %, particularly preferably greater than 40% and smaller than 70%, preferably smaller than 65% and particularly preferably smaller than 60% of the basic distance present at the axial position in the screw channel.

Preferably, at least one screw channel at least partially towards the screw flight with a height-limited gap wall area and / or a height-limited flow area has a radius that is smaller than 1.5 times the screw flight height the mixing gap sections, particularly preferably smaller than 1.2 times the screw flight height of the mixing gap sections and greater than 0.6 times the screw flight height of the mixing gap sections, particularly preferably greater than 0.8 times the screw flight height of the mixing gap sections.

Preferably, at least one mixing zone has at least one axial position at which a mixing gap section or a flow area is present on all screw flights present in the axial position, particularly preferably only one mixing gap section is present on all screw flights present in the axial position. Preferably, a large part of the mixed gap sections, particularly preferably all mixed gap sections, lie in at least one height-limited gap-wall area. The axial position is preferably at least partially in the area of a secondary feed zone.

The extruder preferably has exactly one screw.

In an alternative embodiment, the extruder has at least two screws. It is particularly preferred that at least two screw axes, particularly preferably all of the screw axes, lie parallel to one another.

There are preferably at least two screws with different lengths and / or different screw diameters.

There are preferably a basic screw (GS1) and several additional screws (ZS1), which are distributed circumferentially around the basic screw GS1, with at least some of the additional screws ZS1 having at least one screw flight which at least partially has at least one gap-wall area and / or has a flow region. The basic screw GS1 particularly preferably has at least one screw flight which at least partially has at least one gap-wall area and / or one flow area.

Tests on several prototypes have shown that the inventive design of the additional screws ZS1 and / or the base screw GS1 has a significantly better mixing effect in the circumferential direction, i.e. a transfer of processing material from an additional screw ZS1 in the direction of another additional screw ZS1 and / or to the basic screw GS1 is better and so a better homogeneity of the processing material is achieved with simultaneous optimal conveyance of the processing material.

The invention is to be explained in the following on the basis of various figures.

1 shows, schematically and not to scale, an extruder with a screw.

FIG. 2 shows, schematically and not to scale, part of a screw of an extruder according to aspect 1.

3 shows, schematically and not to scale, part of a screw of an extruder according to aspect 2. 4 shows, schematically and not to scale, part of a screw of an extruder according to aspect 3.

5 shows, schematically and not to scale, part of a screw of an extruder according to aspects 4 and 5.

6 shows, schematically and not to scale, part of a screw of an extruder according to aspect 6.

7 shows, schematically and not to scale, part of an extruder with a screw according to aspects 8 and 9.

8 shows, schematically and not to scale, part of an extruder with a screw according to aspects 8 and 9.

9 shows, schematically and not to scale, part of an extruder with a screw according to aspects 10.

FIG. 10 shows, schematically and not to scale, part of a screw of an extruder according to aspect 11.

11 likewise shows, schematically and not to scale, part of a screw of an extruder according to aspect 11.

12 shows, schematically and not to scale, part of a screw of an extruder.

13 shows, schematically and not to scale, a cross section of a screw and a cylinder.

14 shows, schematically and not to scale, a cross section of a screw.

If it is stated in the description of the figures that something runs downwards or upwards, this is always meant in relation to the orientation of the figure. The alignment of the figure results from the alignment of the text or the reference symbols.

The exact screw flight height of the height-limited areas can hardly be seen in the figures. The screw flight heights in the height-limited areas correspond to 50% of the basic distance between the two surrounding screw channels unless this is expressly stated in the respective context or it is obvious or technically imperative for a person skilled in the art that another value is present there.

1 shows, schematically and not to scale, an extruder with a screw. The discharge direction of the extruder and thus the axial direction 110 result from the direction of the screw axis from the main feed zone to the main discharge zone. The direction of rotation of the worm 111 is downward on the front of the figure. In the present case, a screw with a barrier zone 122 is shown. The dashed line 103 indicates the beginning of the barrier zone 122 and the dashed line 104 indicates the end of the barrier zone 122. A metering zone 123 is present directly after the barrier zone 122. The dashed line 104 marks the beginning of the metering zone 123 and the dashed line 105 marks the end of the metering zone 123. Directly after the metering zone 123 is located a mixing zone 124 before. The dashed line 105 marks the beginning of the mixing zone 124 and the dashed line 106 marks the end of the mixing zone 124. In addition, the dashed line 106 marks the end of the extruder and the axial beginning and the axial end of the main discharge zone of the extruder. The dashed line 101 marks the beginning and the dashed line 102 the end of the main feed zone 121 in the axial direction.

The length of the zone 122, for example, is the axial length extension of the zone 122 along the axial direction 110.

The zones 123 and 124 lie in the axial direction after or behind the zone 122. The zones 122 and 123 lie in the axial direction in front of the zone 124. The zone 123 lies in the axial direction directly after the zone 122 and directly in front of the zone 124.

2 shows, schematically and not to scale, part of a screw of an extruder according to aspect 1. The discharge direction of the extruder and thus the axial direction is indicated by the arrow 210. The arrow 211 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, the homogenization zone 221 is present as a vortex mixing zone with height-limited gap-wall areas between the dashed lines 201 and 202. Immediately after the homogenization zone 221, between the dashed lines 202 and 203, there is the metering zone 222, which only has screw flights with sealing areas. Directly after the metering zone 222, between the dashed lines 203 and 204, there is the second homogenization zone 223, which has more screw flights than the homogenization zone 221. In the embodiment shown, the homogenization zone 223 is a vortex mixing zone with height-limited gap-wall areas and knows twice that many screw flights such as the homogenization zone 221. In addition, the screw flight 231 is present from the beginning of the homogenization zone 221 to the end of the homogenization zone 223, the screw flight ending on the rear side of the illustration like all screw flights of the homogenization zone 223 at the dashed line 204.

3 shows, schematically and not to scale, part of a screw of an extruder according to aspect 2. The discharge direction of the extruder and thus the axial direction is indicated by the arrow 310. The arrow 311 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, a vortex-barrier mixing zone 321 is present between the dashed lines 301 and 303. Here, between the dashed lines 301 and 302, the screw flights 332 and 334 have height-limited flow areas and the screw flights 331 and 333 have sealing areas. In addition, on the screw flights 332 and 334 after the flow areas and on the screw flights 331 and 333 after the sealing areas there are height-limited gap-wall areas up to the dashed line 303. In the embodiment shown, the screw has a constant number of 4 flights in the vortex barrier mixing zone.

Fig. 4 shows schematically and not to scale a part of a screw of an extruder according to aspect 3. The discharge direction of the extruder and thus the axial direction is with the Marked by arrow 410. The arrow 411 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, there is a vortex-tight mixing zone 421 between the dashed lines 401 and 403. Here, between the dashed lines 401 and 402 in the axial part 422 of the screw flights 431, a sealing area has. In the axial part 423, between the dashed lines 402 and 403, a height-limited gap-wall area follows directly after the sealing area on the screw flight 431. On all other screw flights there is a height-limited gap-wall area between the dashed lines 401 and 403. The eddy-sealing mixing zone 421 thus has no sealing area in the axial part 423. In the embodiment shown, the screw in the eddy-sealing mixing zone 421 has a constant number of flights of four.

5 shows, schematically and not to scale, part of a screw of an extruder according to aspects 4 and 5. The discharge direction of the extruder and thus the axial direction is indicated by arrow 510. The arrow 511 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, the vortex mixing zone 521 is present between the dashed lines 501 and 502. All existing gap-wall areas are height-limited gap-wall areas. The spirals 531 and 532 are not components or components of the screw or the extruder, but only serve to illustrate the position of the respective mixing gap sections. In the embodiment shown, the helix 531 has a constant gradient S5 over its entire course and the helix 532 has a constant gradient S6 over its entire course, the gradient S6 being greater than the gradient S5.

All mixing gap sections that lie in the course of the spiral 531, such as the mixing gap section 534, have the same length along the respective screw flight and the same screw flight height.

All mixing gap sections that lie in the course of the spiral 532, such as the mixing gap section 536, have the same length along the respective screw flight and the same screw flight height.

All flight flights, such as flight 537, have both mixing gap sections that lie along turning ice 531 (such as mixing gap section 534) and mixing gap sections that lie along turning ice 532 (such as mixing gap section 536). The length of the mixing gap section 534 along the screw flight 537 is smaller than the length of the mixing gap section 536 along the screw flight 537.

All screw flights, such as the screw flight 537, have both mixing wall sections that lie between two mixing gap sections that lie along the turning ice 531 (such as, for example, mixing wall section 533), as well as mixing wall sections that lie between two mixing gap sections that are along the turning ice 532 ( such as mixing wall section 535). The length of the mixing wall section 533 along the screw flight 537 is smaller than the length of the mixing wall section 535 along the screw flight 537. 6 shows, schematically and not to scale, part of a screw of an extruder according to aspect 6. The discharge direction of the extruder and thus the axial direction is indicated by the arrow 610. The arrow 611 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, the vortex mixing zone 621 is present between the dashed lines 601 and 603. All existing gap-wall areas are height-limited gap-wall areas. The vortex mixing zone 621 has a number of turns of 4 between the dashed lines 601 and 602 in the axial part 622 and a number of 8 turns between the dashed lines 602 and 603 in the axial part 623. The axial part 623 lies directly after the axial part 622.

7 shows, schematically and not to scale, part of an extruder with a screw according to aspects 8 and 9. The discharge direction of the extruder and thus the axial direction is indicated by arrow 710. The arrow 711 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, the extruder has a secondary feed zone 725. The secondary feed zone 725 begins with the beginning of the opening 732 in the cylinder wall 731 at the dashed line 702 and ends with the end of the opening 732 in the cylinder wall 731 at the dashed line 703. The screw has the vortex between the dashed lines 701 and 704. Sealed mixing zone 721, which completely overlies the secondary feed zone 725 and is partially present before and after the secondary feed zone 725. All existing gap-wall areas are height-limited gap-wall areas. The screw has the vortex mixing zone 723 between the dashed lines 705 and 706, which lies completely after the secondary feed zone 725 and also after the vortex-sealing mixing zone 721. All existing gap-wall areas are height-limited gap-wall areas.

The metering zone 722 is located between the eddy-tight mixing zone 721 and the vortex mixing zone 723. After the vortex mixing zone 723, there is a screw tip in the zone 724. The axial end of the screw and the extruder is indicated by the dashed line 707. The dashed line 707 therefore simultaneously identifies the beginning and the end of the main discharge zone 726 in the axial direction.

In the embodiment shown, the axial length of the area of the eddy-sealing mixing zone 721 which is present after the end of the secondary feed zone 725, i.e. the axial length between the dashed line 703 and the dashed line 704, is approximately 35% of the axial length of the area, that is present between the end of the secondary feed zone 725 and the beginning of the main discharge zone 726, that is to say the axial length between the dashed line 703 and the dashed line 707. The axial length of the area of the vortex mixing zone 723 that is present after the end of the secondary feed zone 725, that is, the axial length between the dashed line 705 and the dashed line 706 is approximately 45% of the axial length of the area between the end of the secondary feed zone 725 and the start of the main discharge zone 726. The sum of the two lengths results in approximately 80% of the axial length of the area which is present between the end of the secondary feed zone 725 and the start of the main discharge zone 726. In the embodiment shown, both the vortex-sealing mixing zone 721 and the vortex mixing zone 723 have screw flights with height-limited gap-wall areas.

On 100% of the axial length of the parts of the eddy-sealing-mixing zone 721 and the vortex-mixing zone 723, which are present between the beginning of the secondary feed zone 725 and the end of the main discharge zone 726, there is a height-limited gap-wall area on at least one screw flight .

8 shows, schematically and not to scale, part of an extruder with a screw according to aspects 8 and 9. The discharge direction of the extruder and thus the axial direction is indicated by arrow 810. The arrow 811 indicates the direction of rotation of the worm. This runs down the front of the figure. In the embodiment shown, the extruder has a secondary feed zone 823. The secondary feed zone

823 begins with the beginning of the opening 832 in the cylinder wall 831 at the dashed line 802 and ends with the end of the opening 832 in the cylinder wall 831 at the dashed line 803. The screw has the vortex sealing between the dashed lines 801 and 805. Mixing zone 821, which completely overlies the secondary feed zone 823 and is partially present before and after the secondary feed zone 823. All existing gap-wall areas are height-limited gap-wall areas.

After the eddy-tight mixing zone 821, there is a screw tip in zone 822. The axial end of the screw and extruder is indicated by dashed line 806. The dashed line 806 therefore simultaneously identifies the beginning and the end of the main discharge zone 824 in the axial direction.

In the embodiment shown, the axial length of the area of the eddy-sealing mixing zone 821, which is present between the end of the secondary feed zone 823 and the start of the main discharge zone 824, is more than 90% of the axial length of the area between the end of the secondary feed zone 823 and the beginning of the main play area

824 exists.

The area in which a homogenization zone is present between the end of the secondary feed zone 823 and the start of the main discharge zone 824 is delimited by the dashed lines 803 and 805. A sealing area is present on the screw flight 833 up to the dashed line 804. The axial length from the dashed line 803 to the dashed line 804 corresponds to more than 60% of the axial length from the dashed line 803 to the dashed line 805

9 shows, schematically and not to scale, part of an extruder with a screw according to aspects 10. The discharge direction of the extruder and thus the axial direction is indicated by the arrow 910. The arrow 911 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, the extruder has a secondary discharge zone 923. The secondary discharge zone 923 begins with the beginning of the opening 932 in the cylinder wall 931 at the dashed line 902 and ends with the end of the opening 932 in the cylinder wall 931 at the dashed line 903. The screw has the vortex between the dashed lines 901 and 904 Dense mixing zone 921 which completely overlies the secondary feed zone 923 and is partially present before and after the secondary feed zone 923. All existing gap-wall areas are height-limited gap-wall areas.

After the eddy-tight mixing zone 921, there is a screw tip in zone 922. The axial end of the screw and extruder is indicated by dashed line 905. The dashed line 905 therefore simultaneously identifies the beginning and the end of the main discharge zone 924 in the axial direction.

FIG. 10 shows, schematically and not to scale, part of a screw of an extruder according to aspect 11. The discharge direction of the extruder and thus the axial direction is indicated by the arrow 1010. The arrow 1011 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, the screw has the barrier zone 1021, which is delimited in the axial direction by the dashed lines 1001 and 1003. The dashed line 1001 identifies the beginning of the outlet channel and the dashed line 1003 the end of the inlet channel.

The screw has the screw flight 1031, which has a sealing area up to the dashed line 1004 and from the dashed line 1004 with the beginning of the mixed gap section 1034 has a height-limited gap-wall area. The screw flight 1031 is the main flight of the barrier zone 1021 from the dashed line 1001 to the dashed line 1003.

The screw has the screw flight 1032, which has a narrow flow area. The screw web 1032 is the barrier web of the barrier zone 1021 from the dashed line 1001 to the dashed line 1003.

The screw has the screw flight 1033, which has a height-limited gap-wall area. The screw flight 1033 begins at the dashed line 1002 and is up to the broken line 1003 in the outlet channel 1035 of the barrier zone 1021 and ends at the dashed line 1005. The screw flight 1033 has the same gradient as the screw flight 1031 at each axial position.

The vortex-barrier mixing zone 1022 is present from the dashed line 1000 to the dashed line 1005. It should be expressly noted here that the barrier zone 1021 begins with the beginning of the outlet channel at the dashed line 1001 and the screw flight 1032 with the narrow flow area begins at the dashed line 1000.

From the dashed line 1002 to the dashed line 1003, the vortex-barrier mixing zone 1022 has both the screw flight 1031 with a sealing area and the screw flight 1033 with a height-limited gap-wall area, as well as the screw flight 1032 a narrow flow area. The axial length between the dashed lines 1002 and 1003 is more than 2.5 screw diameters in the embodiment shown.

In addition to the screw flight 1033, there are further screw flights with height-limited gap-wall areas in the outlet channel of the barrier zone 1021. Through all the screw flights with height-limited gap-wall areas in the outlet channel, the homogeneity of the processing material is significantly improved.

11 likewise shows, schematically and not to scale, part of a screw of an extruder according to aspect 11. The discharge direction of the extruder and thus the axial direction is indicated by the arrow 1110. The arrow 1111 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, the screw has the eddy-barrier mixing zone 1121, which is delimited in the axial direction by the dashed lines 1101 and 1105.

The screw has the screw flight 1132, which has a sealing area from the dashed line 1102 to the dashed line 1105. From the dashed line 1101 to the dashed line 1102, the screw flight 1132 has a height-limited gap-wall area which ends with the end of the mixed gap section 1133. From the dashed line 1105 to the dashed line 1106, the screw flight 1132 has a height-limited gap-wall area that begins with the beginning of the

Mix gap section 1134 begins. The screw flight 1132 runs with a right-directed slope around the screw. To the right, the screw has a total of 8 screw flights. All the screw flights except for the screw flight 1132 each have exclusively a height-limited gap-wall area between the dashed lines 1101 and 1106.

The screw has the screw flight 1131, which has a narrow flow area. The screw flight 1131 begins at the dashed line 1103 and ends at the dashed line 1104. The screw flight 1131 runs with a left-hand slope around the screw. The longer the screw flight 1131 is made and the more frequently it crosses the screw flight 1132, the more often the processing material has to flow over it and is sheared in the process, which leads to dissipative mixing. In the embodiment shown, the screw flight 1131 begins at the screw flight 1132, crosses it once (on the back of the drawing and therefore not shown) and finally ends at the screw flight 1132. This means that the processing material has to flow over the screw flight 1131 twice.

From the dashed line 1103 to the dashed line 1104, the eddy-barrier mixing zone 1121 in the embodiment shown has both the screw flight 1132 with a sealing area, as well as 7 screw flights with a height-limited gap-wall area, as well as the screw flight 1131 with a narrow flow area. The axial length between the dashed lines 1103 and 1104 is more than 2.3 screw diameters in the embodiment shown.

By integrating the overflow in a mixing zone, the screw can on the one hand have a shorter and thus more economical design. On the other hand, the processing material is mixed directly distributively before and after the overflow, which can significantly improve the homogeneity of the processing material. FIGS. 12, 13 and 14 serve to clarify various terms and are explained together below. The association of the reference symbols with the numbers of the figures results from the first two digits of the reference symbols.

12 shows, schematically and not to scale, part of a screw of an extruder. The discharge direction of the extruder and thus the axial direction is indicated by the arrow 1210. The arrow 1211 indicates the direction of rotation of the screw. This runs down the front of the figure. In the embodiment shown, the screw 1236 has a vortex-barrier mixing zone which is delimited in the axial direction by the dashed lines 1201 and 1203. The screw 1236 is located in the cylinder 1235.

13 shows schematically and not to scale the cross section of the screw 1236 and the cylinder 1235 on the dashed line 1202. The arrow 1311 indicates the direction of rotation of the screw. The axial direction 1310 goes into the image plane.

14 shows schematically and not to scale the cross section of the screw 1236 on the dashed line 1202. The arrow 1411 indicates the direction of rotation of the screw. The axial direction 1410 goes into the image plane. This figure is intended to clarify the association of the lines with the screw and cylinder in FIG.

The screw flight 1231 has a sealing area continuously from the dashed line 1201 to the dashed line 1203.

The screw flight 1232 has a height-limited gap-wall area continuously from the dashed line 1201 to the dashed line 1203.

The screw flight 1233 has a height-limited flow area continuously from the dashed line 1201 to the dashed line 1203.

The screw flight 1234 has a narrow flow area continuously from the dashed line 1201 to the dashed line 1203.

The arrow 1312 indicates the basic distance of the screw channel between the screw flight 1231 and the screw flight 1234 at the axial position which is indicated by the dashed line 1202. In the embodiment shown, all screw channels have the same basic spacing at the axial position, which is indicated by the dashed line 1202. This is indicated by the dashed circle 1301. In the embodiment shown, all screw channels have the same basic spacing over the entire length of the vortex-barrier mixing zone.

All screw flights have a radius on both sides of the screw base of the screw channels which corresponds to 50% of the basic distance between the screw channels. Such a radius is fundamentally useful for improved flow and vortex formation in the mixing zones according to the invention, but was not shown in the previous figures for reasons of clarity.

The arrow 1313 identifies the flight distance of the screw flight 1231, which has a sealing area. The worm clearance corresponds to this web spacing, since this Web spacing is the smallest existing web spacing of all webs at the respective axial position.

The arrow 1314 indicates the flight distance of the screw flight 1234, which has a narrow flow area. In the embodiment shown, the flight distance corresponds to 10% of the basic distance and thus the screw flight height corresponds to 90% of the basic distance.

The arrow 1315 indicates the flight distance of the screw flight 1233, which has a height-limited flow area. In the embodiment shown, the flight distance corresponds to 55% of the basic distance and thus the screw flight height corresponds to 45% of the basic distance.

The arrow 1316 indicates the web spacing of a mixing wall section of the screw web 1232, which has a height-limited gap-wall area. In the embodiment shown, the flight distance corresponds to 10% of the basic distance and thus the screw flight height corresponds to 90% of the basic distance. The mixing wall section thus also has the screw play as the web spacing.

The arrow 1317 indicates the web spacing of a mixing gap section of the screw flight 1232, which has a height-limited gap-wall area. In the embodiment shown, the flight distance corresponds to 55% of the basic distance and thus the screw flight height corresponds to 45% of the basic distance.

List of the reference symbols used

101 dashed line (dividing line)

102 dashed line (dividing line)

103 Dashed line (dividing line)

104 dashed line (dividing line)

105 dashed line (dividing line)

106 dashed line (dividing line)

110 Axial direction

111 Direction of rotation of the screw

121 Main feed zone

122 barrier zone

123 metering zone

124 mixing zone

201 dashed line (dividing line)

202 dashed line (dividing line)

203 dashed line (dividing line)

204 dashed line (dividing line)

210 Axial direction

211 Direction of rotation of the screw

221 homogenization zone

222 metering zone

223 homogenization zone Screw flight Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Axial direction of rotation of the screw Vortex barrier mixing zone Screw flight of screw flight Screw flight of screw flight Dashed line (separation line) Dashed line (separation line) Dashed line (separation line) Axial direction of rotation direction of the screw Eddy-tight mixing zone Axial part Axial part Screw flight Dashed line (dividing line) Dashed line (dividing line) Axial direction of rotation of the screw Vortex mixing zone Helix Helix Mixing wall section Mixing gap section Mixing wall section Mixing gap section Screw flight Dashed line (separating line) Dashed line (separating line) Dashed line (separating line) Axial direction Direction of rotation of the screw Vortex mixing zone Axial part Axial part Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Axial direction Rotation direction of the screw Eddy-sealing-mixing zone Metering zone Eddy-mixing zone Zone

Secondary feed zone

Cylinder wall

opening

Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Dashed line (dividing line) Axial direction Rotation direction of the screw Vortex-sealing-mixing zone zone

Secondary feed zone

Main staging area

Cylinder wall

opening

Screw flight

Dashed line (dividing line)

Axial direction

Direction of rotation of the screw

Eddy-tight mixing zone

Zone

Secondary feed zone

Main staging area

Cylinder wall

opening 933 screw flight

1000 dashed line (dividing line)

1001 dashed line (dividing line)

1002 dashed line (dividing line)

1003 dashed line (dividing line)

1004 Dashed line (dividing line)

1005 dashed line (dividing line)

1010 Axial direction

1011 Direction of rotation of the screw

1021 barrier zone

1022 vortex barrier mixing zone

1031 screw flight

1032 screw flight

1033 screw flight

1034 screw flight

1101 dashed line (dividing line)

1102 dashed line (dividing line)

1103 dashed line (dividing line)

1104 dashed line (dividing line)

1105 dashed line (dividing line)

1106 dashed line (dividing line)

1110 Axial direction

1111 Direction of rotation of the screw

1121 barrier zone

1122 vortex barrier mixing zone

1131 screw flight

1132 screw flight

1133 mixed gap section

1134 mixed gap section

1201 dashed line (dividing line)

1202 dashed line (dividing line)

1203 dashed line (dividing line)

1210 Axial direction

1211 Direction of rotation of the screw

1221 vortex-tight mixing zone

1222 metering zone

1223 Vortex mixing zone

1224 zone

1225 secondary feed zone

1231 screw flight

1232 screw flight

1233 screw flight 1234 screw flight

1235 cylinder wall

1236 snail

1301 Dashed circle (symbol for screw bottom)

1310 Axial direction

1311 Direction of rotation of the worm

1312 arrow (indicator for basic distance)

1313 arrow (indicator for web spacing)

1314 arrow (indicator for web spacing)

1315 arrow (indicator for web spacing)

1316 arrow (indicator for web spacing)

1317 arrow (indicator for web spacing)

1410 Axial direction

1411 Direction of rotation of the worm

Claims

1) Extruder with at least one screw for processing a processing material, with at least one screw having at least two homogenization zones (HZ1 (221) and HZ2 (223)), with a height-limited gap-wall area denoting the area of a screw flight on which a The gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections having a screw flight height of at least 30% and a maximum of 70% of the basic distance to the two surrounding screw channels, with a height-limited flow area denoting the area from a screw flight to which a flow area ends both surrounding screw channels has a screw flight height of at least 30% and a maximum of 70% of the basic distance present at the point, characterized in that the homogenization zone HZ1 (221) is a mixing zone which on at least one screw flight (231) at least partially has at least one height-limited gap- Wall -Area and / or has at least partially at least one height-limited flow area on a screw flight and the homogenization zone HZ2 (223) has at least the same number of screw flights as the homogenization zone HZ1 (221), preferably has more screw flights, particularly preferably an integral multiple of the screw flights Has homogenization zone HZ1 (221), the homogenization zone HZ1 (221) lying in front of the homogenization zone HZ2 (223).

2) Extruder with at least one screw for processing a processing material, a height-limited gap-wall area denoting the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections leading to both surrounding screw channels have a screw flight height of a minimum of 30% and a maximum of 70% of the basic distance, with a height-limited flow area denoting the area of a screw flight on which a flow area to both surrounding screw channels has a screw flight height of a minimum of 30% and a maximum of 70% of the basic distance present at the point , characterized in that at least one screw has at least one screw flight (333) on which there is at least partially at least one height-limited gap-wall area and at least one screw flight (332) on which there is at least one height-limited flow area, preferably at least one height-limited flow area after at least one height-limited gap-wall area.

3) Extruder with at least one screw for processing a processing material, with a height-limited gap-wall area denoting the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections leading to both surrounding screw channels have a screw flight height of at least 30% and a maximum of 70% of the basic distance, characterized in that at least one screw flight has a height-limited gap-wall area in at least one axial part (422) of the screw and at least one screw flight (431) has a sealing area and in at least one other axial part (423) of the screw at least one screw flight (431) has a height-limited gap-wall area and no screw flight has a sealing area.

4) Extruder with at least one screw for processing a processing material, at least one screw having at least one mixing zone (521) which has at least one screw flight (537) which at least partially has at least one height-limited gap-wall area, one height-limited gap -Wall area denotes the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections having a screw flight height of a minimum of 30% and a maximum of 70% of the basic distance to the two surrounding screw channels, characterized that at least three, preferably at least four, particularly preferably at least five mixing gap sections (534) in the mixing zone have the same screw flight height and the same length along the respective screw flight.

5) Extruder with at least one screw for processing a processing material, at least one screw having at least one mixing zone (521) which has at least one screw flight (537), a height-limited gap-wall area being the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections having a screw flight height of at least 30% and a maximum of 70% of the basic distance to the two surrounding screw channels, characterized in that the screw flight has at least two mixing gap sections (534 , 536) with different lengths along the screw flight, which are located in at least one height-limited gap-wall area and / or at least two mixed wall sections (533, 535) with different lengths along the screw flight, which are in at least one height-limited gap Wall area are located, whereby the differences in length along the screw flight of mixed gap sections and mixed wall sections that are located directly at the beginning or at the end of the respective gap-wall area are not taken into account.

6) Extruder with at least one screw for processing a processing material, the screw having at least one mixing zone (621) which has at least one screw flight which at least partially has at least one height-limited gap-wall area and / or at least partially at least one height-limited flow area , a height-limited gap-wall area denotes the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections having a screw flight height of at least 30% and a maximum of 70% of the two surrounding screw channels A height-limited flow area denotes the area of a screw flight on which a flow area to both surrounding screw channels has a screw flight height of a minimum of 30% and a maximum of 70% of the base distance present at the point, characterized in that s there is a higher number of flights in at least one axial part (623) of the mixing zone than in another axial part 622) of the mixing zone, with an integral multiple of the number of flights of the axial part (622) preferably being present in the axial part (623).

7) Extruder with at least one screw for processing a processing material, the screw having at least one mixing zone with at least one screw channel, the screw channel at least partially on at least one side having a screw flight with at least one height-limited gap-wall area and / or at least one height-limited area Has flow range, A height-limited gap-wall area denotes the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections having a screw flight height of a minimum of 30% and a maximum of 70% of the basic distance to the two surrounding screw channels a height-limited flow area denotes the area of a screw flight on which a flow area to both surrounding screw channels has a screw flight height of a minimum of 30% and a maximum of 70% of the basic distance present at the point, characterized in that the quotient of the maximum basic distance over the maximum width of the screw channel in the area of the mixing zone over an axial length of at least 0.5 times the screw diameter at each axial position is a maximum of 1.4 and a minimum of 0.1.

8) Extruder with at least one screw for processing a processing material, the extruder having at least one secondary feed zone (725) and the screw having at least one screw flight which at least partially has at least one height-limited gap-wall area and / or at least partially at least one height-limited flow area a height-limited gap-wall area denotes the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections having a screw flight height of a minimum of 30% and a maximum of 70% to the two surrounding screw channels of the base distance, with a height-limited flow area denoting the area of a screw flight on which a flow area to both surrounding screw channels has a screw flight height of at least 30% and a maximum of 70% of the base distance present at the point, dadurc h characterized in that at least a part of the height-limited gap-wall area and / or at least a part of the height-limited flow area lies after the secondary feed zone (725).

9) Extruder with at least one screw for processing a processing material, the extruder having at least one secondary feed zone (823) and at least part of at least one homogenization zone (821) between the end of the first secondary feed zone (823) and the beginning of the main discharge zone (824) , the areas of all parts of all homogenization zones (821) which lie between the end of the first secondary feed zone (823) and the start of the main discharge zone (824) are combined in the group (HAR1), A height-limited gap-wall area denotes the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections having a screw flight height of a minimum of 30% and a maximum of 70% of the basic distance to the two surrounding screw channels have, with a height-limited flow area denoting the area of a screw flight on which a flow area to both surrounding screw channels has a screw flight height of at least 30% and a maximum of 70% of the basic distance present at the point, characterized in that the sum (AL1) of the axial Lengths of the areas of group HAR1, is greater than 50% of the axial length (AL2) of the area from the end of the first secondary feed zone (823) to the start of the main discharge zone (824), preferably greater than 65%, particularly preferably greater than 80 % of the axial length AL2, with a homogenization in at least one area zone (821) of group HAR1 has at least one mixing zone which has at least partially at least one height-limited gap-wall area and / or at least one height-limited flow area on at least one screw flight.

10) Extruder with at least one screw for processing a processing material, the extruder having at least one secondary discharge zone (923) and the screw having at least one mixing zone (921) which has at least one screw flight, which at least partially has at least one height-limited gap-wall area and / or at least partially has at least one height-limited flow area, a height-limited gap-wall area denoting the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections having one to both surrounding screw channels Have a screw flight height of a minimum of 30% and a maximum of 70% of the basic distance, with a height-limited flow area denoting the area of a screw flight on which a flow area to both surrounding screw channels has a screw flight height of a minimum of 30% and a maximum of 70% of that at the Ste All the basic spacing present, characterized in that the area of at least one mixing zone (921) is at least partially superimposed on the area of the secondary discharge zone (923).

11) Extruder with at least one screw for processing a processing material, A height-limited gap-wall area denotes the area of a screw flight on which a gap-wall area has at least two mixing gap sections, with at least 50% of the mixing gap sections having a screw flight height of a minimum of 30% and a maximum of 70% of the basic distance to the two surrounding screw channels a height-limited flow area denotes the area of a screw flight, on which a flow area to both surrounding screw channels has a screw flight height of at least 30% and a maximum of 70% of the basic distance present at the point, with a narrow flow area denoting the area of a screw flight, on which a flow area to at least one surrounding screw channel has a screw flight height of more than 70% of the basic distance present at the point, characterized in that the screw is in at least one axial position, preferably on an axial part of the screw with an a axial length of at least one screw diameter, particularly preferably on an axial part of the screw with an axial length of at least two screw diameters, has at least one screw flight (1033) which has a height-limited gap-wall area or a height-limited flow area and at least one further screw flight ( 1032) which has a narrow flow area and preferably has at least one screw flight (1031) which has a sealing area.