Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
  • B29B7/00—Mixing; Kneading
  • B29B7/30—Mixing; Kneading continuous, with mechanical mixing or kneading devices
  • B29B7/34—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices
  • B29B7/38—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary
  • B29B7/40—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft
  • B29B7/42—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft with screw or helix
  • B29B7/421—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with single shaft with screw or helix with screw and additionally other mixing elements on the same shaft, e.g. paddles, discs, bearings, rotor blades of the Banbury type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/256—Exchangeable extruder parts
  • B29C48/2564—Screw parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/50—Details of extruders
  • B29C48/505—Screws
  • B29C48/52—Screws with an outer diameter varying along the longitudinal axis, e.g. for obtaining different thread clearance
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/50—Details of extruders
  • B29C48/505—Screws
  • B29C48/57—Screws provided with kneading disc-like elements, e.g. with oval-shaped elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion

Definitions

• the invention relates to a screw element according to the preamble of claim 1.
• plasticizing unit such as those in extruders or in injection molding machines
• a variety of methods are used.
• One of these methods is compounding, i. the incorporation of fillers or reinforcing agents, incorporation of paints or pigments, blending of various materials, e.g. Plastics or elastomers, reactive processes or the like. All methods have in common that this is done by means of two- or multi-shaft extruder having in the same direction or in opposite directions rotating screws.
• Scissor energy is used to melt the plastic materials into the material by means of the screws.
• the screws have so-called screw elements, which are often designed to be multi-threaded.
• a special screw element is the so-called kneading element, also called kneading block in the literature.
• a kneading block consists of spiral-shaped screw parts or a plurality of kneading units arranged one behind the other in the direction of the method and having a certain geometry.
• the geometry of the kneading units especially in terms of their width and their outside and inside diameters, is the same, and is determined by the size of the plasticizing unit, i. the plasticizing unit of the extruder or the injection molding machine selected.
• the dissipation of the mechanical energy introduced via the drive via a gear and via the worm shaft is determined by, for example, the dependence of the enthalpy of the plastic to be processed on the type of worm assembly used.
• the type of screw assembly used is also called configuration.
• the configuration varies, for example, in the type and number of kneading blocks and the other screw elements.
• the main conversion of the energy depending on the geometry of the screw elements is achieved directly in front of and above the first or the first kneading elements. This major transformation of energy is through shear.
• the gaps between the kneading unit and the extruder housing and in a twin-screw extruder the kneading units in the gusset area and the comb surface of the kneading elements are determining. From these quantities, the shear rate as well as the shear stress can be calculated accordingly. About the shear stress results in the melting of the material to be plasticized. During melting, the highest mechanical loads for the screw element and their shaft / hub connection result.
• Such a kneading element is known from the registered documents of German Utility Model 82 32 585.
• the screw element shown there comprises individual kneading units, which can be plugged together to form a kneading element.
• the kneading units have the same geometry.
• DE 100 50 295 A1 describes a multi-shaft extruder for the treatment and / or processing of an elastomer filled with filler with at least two shafts, which in the conveying direction comprise a filling zone, a mastifying zone and a dispersing zone.
• the masticating as well as the dispersing section may have kneading disks whose maximum diameter increases or decreases in the direction of production.
• JP 2004202871 a kneading screw is described which has a kneading section between two conveying sections whose kneading disks have a continuously increasing diameter in the conveying direction.
• the present invention is therefore based on the object of specifying a screw element of the type mentioned, in which a good plasticization of the material to be processed is made possible with reduced mechanical stress on the screw elements.
• the screw element in question is designed and refined such that the geometry of at least two successively arranged kneading units differs, wherein the width of the kneading units increases in the process direction
• the width of at least two kneading units could be different. This would affect the shear gap to change the shear area. As in the case of a change in the diameter of the kneading unit, which will be discussed below, this could take place within one or more successive screw elements.
• the kneading units or screw parts do not have the same width throughout the width of the screw element.
• the kneading units or screw sections could not consistently have a same diameter.
• the screw elements could be independent of the number of elements in the screw. Thus, the disk land width variability could extend over several screw elements. The screw elements could thus be independent of length.
• the width of the kneading units increases in the process direction. This would also increase the shear of the material to be plasticized in the process direction.
• the direction of the plasticizing unit in which the material to be plasticized and / or plasticized is essentially transported, is thus defined as the method direction.
• the sequence of variability of the width of the kneading units does not have to increase steadily, but may be partially the same.
• it has been recognized that to obtain a good plasticization with reduced mechanical stress of the screw element can deviate from the known shape of the same geometry of the kneading units. If one chooses different geometries, namely different widths, in the kneading units, it is possible to control the initiation of the shear and the mechanical load and to optimize the respective method.
• the use of the screw elements according to the invention is possible in a large number of plasticizing units and a wide variety of methods.
• the kneading elements according to the invention are conceivable in two- or multi-shaft, in the same direction or in opposite directions rotating plasticizing.
• the screw elements are designed to be single or multi-threaded, consist of spiral-shaped screw parts or integrally executed or loosely connected kneading units.
• the kneading units are selected depending on the size of the plasticizing unit and the respective process task.
• the inventive design of the screw element is therefore independent of the size of the machine and the diameter of the screw element.
• the screw elements are independent of the type of shaft / hub connection and the mobility of the screw element.
• the screw elements can furthermore be used in any type of material to be plasticized and are independent of the Da / D ratio and the direction of rotation of the screws.
• the geometry of the kneading units is designed such that a continuous increase in the shear of the material to be plasticized can be achieved.
• the diameter of at least two kneading units could also be different.
• the shearing gap formed between the kneading unit and the extruder housing would be larger or smaller in the direction of the method. be stopped.
• the diameters of the individual kneading units or sections could increase in the process direction.
• the kneading units and kneading elements arranged one behind the other could have different diameters throughout.
• the variability of the geometry thus has a direct influence on the development of the shear rate and the shear stress in front of and in the screw element as well as on the development of the mechanical loading of the elements.
• the Da / Dj ratio of the kneading units may be constant or vary in the screw element according to the invention.
• the diameter and the width of at least two kneading units could be different. This would allow a particularly large variability of the shear gap. Such a configured screw element would also be particularly adaptable to a variety of process tasks.
• both the diameter and the width of the kneading units in the process direction could increase.
• 1 is a schematic plan view of an embodiment of a screw element with variable diameter
• FIG. 2 shows a schematic side view of the embodiment of a variable diameter screw element shown in FIG. 1, FIG.
• Fig. 3 is a schematic plan view of an embodiment of a screw element according to the invention with variable width of the kneading unit and
• Fig. 4 is a schematic side view of the embodiment shown in Fig. 3 of a screw element according to the invention with variable width of the kneading unit.
• the screw element is a kneading element 1, which is used for use in a plasticizing unit, not shown, with a worm shaft, also not shown.
• the kneading element 1 is composed of kneading units 2, which are firmly connected to each other in this embodiment.
• the kneading units 2 can be arranged on a common axis.
• the kneading units 2 have a toothing, which can be brought into engagement with a toothing on the worm shaft and thus the kneading element is fixed substantially rotationally fixed on the worm shaft.
• the kneading units 2 have a geometry which is determined by two diameters Di and D a , ie the diameters D 1 and D 2 , D 3 or D 4 .
• the geometry of two kneading units 2 arranged one after the other differs.
• the external diameter of the kneading element 2 shown in FIG. knife D 3 increases in the process direction.
• the kneading unit 2 with the smallest diameter Di in this embodiment is arranged closest to the feeding zone and the kneading disk 2 with the outside diameter D 4 is arranged furthest in the direction of the discharge zone.
• D 4 is greater than D 3 and D 3 is greater than D 2 .
• Di is again smaller than D 2 , ie Di ⁇ D 2 ⁇ D 3 ⁇ D 4 .
• the inner diameter Di of the kneading element 1 remains constant. It is conceivable in any configuration that the inner diameter Dj varies according to or other than the outer diameter D a .
• FIG. 2 shows the kneading element 1 shown in FIG. 1 in a schematic side view.
• the kneading element 1 of this embodiment has an overall width B.
• the kneading units 2 in turn have a width b.
• FIG. 3 shows a kneading element according to the invention with a variable web width, ie that the kneading units 2 have different widths b.
• the diameter ratio DJD 1 is constant in this embodiment. It should also be noted that the outer diameter D 3 is also constant.
• the width b of the kneading units 2 increases in the process direction. Thus, the shear of the material over the width B of the kneading element 1 is increased.
• the width bi of the kneading unit 2 which is arranged closest to the feeding zone in this kneading element 1, is smaller than the width b 2 .
• the width b 2 is again smaller than the width b 3 .
• the width b 4 of the next kneading unit 2 is again greater than the width b 3 of the previous kneading unit 2. Furthermore, the width bs of the kneading unit 2, which is located farthest in the direction of the discharge zone with respect to this kneading element 2, is greater than the width b 4 . ie bi ⁇ b 2 ⁇ b 3 ⁇ b 4 .

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Related Child Applications (1)

Publications (1)

Family

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Family Applications (1)

Country Status (9)

Cited By (1)

Families Citing this family (5)

Citations (4)

Family Cites Families (35)

• 2006
  • 2006-03-28 DE DE102006014692A patent/DE102006014692B3/de not_active Expired - Fee Related
• 2007
  • 2007-02-16 TW TW096105903A patent/TWI432309B/zh not_active IP Right Cessation
  • 2007-03-21 CA CA2644925A patent/CA2644925C/en not_active Expired - Fee Related
  • 2007-03-21 CN CN2007800087319A patent/CN101400500B/zh not_active Expired - Fee Related
  • 2007-03-21 WO PCT/EP2007/002482 patent/WO2007112861A1/de not_active Ceased
  • 2007-03-21 JP JP2009501912A patent/JP5130285B2/ja not_active Expired - Fee Related
  • 2007-03-21 RU RU2008142522/05A patent/RU2442688C2/ru not_active IP Right Cessation
  • 2007-03-21 EP EP07711985.7A patent/EP2001650B1/de active Active
• 2008
  • 2008-09-16 US US12/211,410 patent/US20090016147A1/en not_active Abandoned

Patent Citations (4)

Non-Patent Citations (1)

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