WO2008075941A1 - Appareil à extruder, ensemble comprenant des vis pivotant dans le sens inverse des aiguilles d'une montre fonctionnant mutuellement, vis destiné à celui-ci et procédé servant à produire une telle vis - Google Patents

Appareil à extruder, ensemble comprenant des vis pivotant dans le sens inverse des aiguilles d'une montre fonctionnant mutuellement, vis destiné à celui-ci et procédé servant à produire une telle vis Download PDF

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Publication number
WO2008075941A1
WO2008075941A1 PCT/NL2007/000321 NL2007000321W WO2008075941A1 WO 2008075941 A1 WO2008075941 A1 WO 2008075941A1 NL 2007000321 W NL2007000321 W NL 2007000321W WO 2008075941 A1 WO2008075941 A1 WO 2008075941A1
Authority
WO
WIPO (PCT)
Prior art keywords
screw
mixing
extruder
flank
mixing holes
Prior art date
Application number
PCT/NL2007/000321
Other languages
English (en)
Inventor
Dirk Jan Starke
Original Assignee
Rollepaal B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rollepaal B.V. filed Critical Rollepaal B.V.
Publication of WO2008075941A1 publication Critical patent/WO2008075941A1/fr

Links

Classifications

    • 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
    • B29C48/72—Feedback means, i.e. part of the molten material being fed back into upstream stages of the extruder
    • B29C48/725—Feedback means, i.e. part of the molten material being fed back into upstream stages of the extruder for plasticising or homogenising devices
    • 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
    • B29B7/46—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft
    • B29B7/48—Mixing; Kneading continuous, with mechanical mixing or kneading devices with movable mixing or kneading devices rotary with more than one shaft with intermeshing devices, e.g. screws
    • B29B7/488—Parts, e.g. casings, sealings; Accessories, e.g. flow controlling or throttling devices
    • B29B7/489—Screws
    • 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
    • B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
    • 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
    • B29C48/395—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders
    • B29C48/40—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders
    • B29C48/402—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using screws surrounded by a cooperating barrel, e.g. single screw extruders using two or more parallel screws or at least two parallel non-intermeshing screws, e.g. twin screw extruders the screws having intermeshing 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
    • B29C48/59—Screws characterised by details of the thread, i.e. the shape of a single thread of the material-feeding screw
    • B29C48/605—Screws characterised by details of the thread, i.e. the shape of a single thread of the material-feeding screw the thread being discontinuous
    • 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 present invention relates to an extruder, to a set of mutually cooperating, counter-rotating screws, to a screw therefor and to a method for manufacture thereof.
  • thermally sensitive plastics for instance PVC
  • the thermally sensitive plastic is placed under pressure as melt and pressed through the distal extrusion tool.
  • the two screws mutually cooperate, thereby creating C-shaped chambers in which the thermally sensitive plastic is transported in the direction of the extrusion tool.
  • the screws have a mutual clearance. Firstly, a roller clearance at the distance between the outer diameter of the one screw and the minor diameter of the other screw. Secondly, a flank clearance between the flanks of the screws.
  • the roller clearance is generally constant. A back-flow of material can be adjusted by varying the flank clearance.
  • a first known method for improving the homogeneity is to arrange grooves in the screw flanks, particularly in the part of the screw adjoining the extrusion tool. Plastic melt will flow back as leakage flow via the grooves, thereby improving mixing, although the pressure build-up is less as a result of the reduced pumping action due to the leakage flow.
  • Another known possibility for improving the homogeneity is to embody the distal part of the screw with a greater number of screw turns, fo_ _ three-threaded screw part in combination with a two-threaded screw part located upstream thereof.
  • the present invention has for its object to provide another method of improving the homogeneity of the extruded product, by improving in a different manner the mixing action through the back-flow of the product for' extruding.
  • the extruder according to the invention comprises: two mutually cooperating, counter-rotating screws, wherein at least one screw is provided along a part of its length with mutually longitudinal cylindrical back-mixing holes arranged at least in its screw flank.
  • the back-mixing is therefore realized according to the invention by arranging a number of back-mixing holes in the screw flank, through which holes the material for extruding can flow back.
  • the part of the screw which is provided with back-mixing holes is situated in a mixing zone.
  • the back-mixing can be further enhanced by increasing the pump volume in that the pitch Sm of the screw in the mixing part provided with back-mixing holes is p whil _, -, the pitch Sp in an adjacent pumping zone, is preferably at least 5% greater, is more preferably at least 10% greater, is still more preferably more than 20% greater.
  • the pitch Sm in the mixing zone can for instance amount to 100 to 140, for instance 120, while in the pumping zone the screw has a pitch Sp of 60 to 100, for instance 80.
  • the mixing action can be further improved if a flank clearance in the part of the screw provided with back-mixing holes is more preferably greater than the flank clearance in an adjacent pumping zone, the flank clearance preferably being at least 10% greater, more preferably 15% greater, still more preferably 20% greater.
  • the mixing action is thus further enhanced as desired by adjusting the flank clearance.
  • part of the screw provided with back-mixing holes is multi-threaded relative to an adjoining part, preferably three-threaded relative to two-threaded, the mixing action is further improved by the multi-threaded transition, whereby the material from a
  • C-shaped chamber is distributed over a plurality of smaller C-shaped chambers in the adjacent multi-threaded part, which enhances the mixing action.
  • the pumping zone and the mixing zone in the screws according to the invention can be situated immediately upstream of the extrusion tool, it is also possible that a plurality of pumping/mixing zones can be arranged along the length of the pair of mutually cooperating, counter-rotating screws, for instance with a view to admixing of different materials and/or the degassing or admitting of other materials via vacuum.
  • the screw part provided with back-mixing holes forms a distal mixing screw part
  • the adjacent screw part forms a proximal pumping screw part.
  • Another aspect of the invention relates to a set of mutually cooperating, counter-rotating screws, wherein at least one screw is provided along a part of its length with back-mixing holes arranged in its screw flank.
  • the back-mixing holes are arranged partly in the screw flank and partly in the screw core.
  • the screw shank is thus provided with a ⁇ __ _ __ _ ___, hole.
  • the part of the screw shank located between adjacent screw flanks is preferably also provided with this part of the mixing hole. It is thus possible that relatively large back-mixing holes can be arranged. It is even possible to arrange back-mixing holes with a diameter greater than the screw flank because a part of the back-mixing hole is located in the screw core. Because the exposed surface of the screw core between adjacent flanks is further provided with a part of the back-mixing hole, the mixing action is further enhanced as a result of the now occurring "cavity transfer" as a result of the flank of the other screw engaging and rotating in this screw turn. It will be apparent that by arranging larger back-mixing holes, for instance larger than the flank height, clogging in the back-mixing holes is further prevented, particularly in the case of large flank widths .
  • the part of the screw provided with the back-mixing holes can be arranged downstream as well as more upstream in the screw. In the case of an upstream arrangement it is further recommended that the screw is divided and the screw part provided with back-mixing holes is placed therebetween.
  • Another aspect of the invention relates to a screw for an extruder or for a set of mutually cooperating, counter-rotating screws, wherein this screw is provided on at least a part of its length with back-mixing holes arranged in its screw flank.
  • a final aspect of the invention relates to a method for manufacturing a screw for an extruder, which screw is provided on a part of its length with back-mixing holes arranged at least in its screw flank, comprising of - arranging longitudinal holes in the screw body;
  • Figure 1 shows a perspective view of an extruder according to the invention
  • Figure 2 shows detail II of figure 1 on larger scale
  • Figure 3 shows a cross-section along line III-III in figure 1;
  • Figure 4 shows a view as according to arrow IV in figure 1;
  • FIGS 5-7 show side views of screws according to the invention.
  • Figure 8A shows a side view of a variant of a screw according to the invention
  • Figure 8B shows a view as according to arrow VIII in figure 8A;
  • Figures 9A-9D show a method for manufacturing a screw part according to the invention.
  • Figures 1OA and 1OB show side views of the assembly of another screw according to the invention.
  • Figure 1 shows an extruder 1 according to the invention.
  • the extruder comprises a hopper 2 for the extruder material, a drive 3 and a set 6 of mutually cooperating, counter-rotating screws 7 and 8 accommodated in a heatable casing 4 in a cylinder 5.
  • Figure 2 shows set 6 on larger scale.
  • Figure 7 shows a side view of screw 7.
  • FIG 3 shows the two-threaded screw 8, which is arranged rotatably in cylinder 5, thus forming C-shaped mixing chambers 9.
  • Flank clearance 10 can further be seen, and in figure 4 roller clearance 11.
  • the counter movement of screws 7 and 8 is shown with arrows 12 and 13, which point in opposite directions.
  • the screw 7 has a pitch of for instance 80 for the two screw turns 12 and 13.
  • Adjacently of screw head 14 the part 15 is provided with mutually longitudinally cylindrical back-mixing openings 16 arranged in longitudinal direction in the screw turns.
  • a number of such back-mixing openings 16 are arranged distributed over a pitch of the screw turns subject to the desired back-mixing to be achieved.
  • Back-mixing openings 16 are preferably polished smooth .— prevent scaling and to enhance self-cleaning. Openings 16 can diverge in through-flow direction.
  • the pitch in mixing zone 18 is greater than in the preceding upstream pump part 19 of screw 17.
  • the pitch Sm in part 18 amounts to for instance 120 and pitch Sp in part 19 amounts to for instance 80.
  • Screw 17 is two-threaded along its whole length, although the improved homogeneity is nevertheless achieved by the improved back-mixing as a result of back-mixing openings 16 arranged in the two screw turns in part 18.
  • Figure 5 shows a screw 20 with a pump part 21 with a pitch Sp 80 and a mixing part 22 with a pitch Sm 120.
  • the screw 20 has a two-threaded form and in part 22 a three-threaded form. This creates a transition 23.
  • a number of back-mixing grooves 24 are further also arranged over a pitch of the three screw turns for the purpose of improving the mixing.
  • FIG 8A shows another screw 25 according to the invention.
  • Screw 25 comprises a screw head 14 and a part 26 which is provided with a screw 27 with a part of a back-mixing hole arranged in screw flank 28. The remaining part of the back-mixing hole is arranged in screw core 30.
  • Longitudinal holes 32 thus result in screw core 30, particularly in the exposed surface in screw turns 31.
  • a so-called cavity transfer mixing results whereby the mixing action is further improved.
  • Figure 8B further shows that mixing hole 29 has a diameter which is almost equal to height h of the screw flank.
  • FIGS 9A-9D show a method for manufacturing a screw part according to the invention which is provided with back-mixing holes in a screw flank of the screw.
  • a solid screw body 33 is provided on an end surface 34 with longitudinal bore holes 35 which, as is shown in figure 9B, have a mutually differing length.
  • FIGS. 1OA and 1OB show a screw tip 40 according to the invention, wherein a part 41 of the screw is provided with screw flanks with mixing holes 44 arranged in screw flank 42 and in screw core 43. This part 41 lies upstream of a downstream part 45 of screw 40. Screw part 41 is manufactured according to the method as shown in figures
  • back-mixing can be further optimized as desired by increasing the flank clearance in the mixing zones .

Landscapes

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

Abstract

L'invention concerne un appareil à extruder (1), comprenant deux vis (78) pivotant dans le sens inverse des aiguilles d'une montre fonctionnant mutuellement, au moins une vis étant dotée le long d'une partie de sa longueur de trous cylindriques rétromélangés mutuellement longitudinaux disposés au moins dans leur face de vis, jusqu'à une vis et un ensemble de vis destiné à celui-ci. L'invention concerne en outre un procédé consistant à fabriquer une telle vis pour l'appareil à extruder.
PCT/NL2007/000321 2006-12-19 2007-12-19 Appareil à extruder, ensemble comprenant des vis pivotant dans le sens inverse des aiguilles d'une montre fonctionnant mutuellement, vis destiné à celui-ci et procédé servant à produire une telle vis WO2008075941A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL1033085A NL1033085C2 (nl) 2006-12-19 2006-12-19 Extruder, samenstel van in elkaar grijpende, tegen elkaar indraaiende schroeven, een schroef daarvoor, en een werkwijze voor het vervaardigen van een dergelijke schroef.
NLNL1033085 2006-12-19

Publications (1)

Publication Number Publication Date
WO2008075941A1 true WO2008075941A1 (fr) 2008-06-26

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ID=38326159

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NL2007/000321 WO2008075941A1 (fr) 2006-12-19 2007-12-19 Appareil à extruder, ensemble comprenant des vis pivotant dans le sens inverse des aiguilles d'une montre fonctionnant mutuellement, vis destiné à celui-ci et procédé servant à produire une telle vis

Country Status (2)

Country Link
NL (1) NL1033085C2 (fr)
WO (1) WO2008075941A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2535165A1 (fr) * 2011-06-16 2012-12-19 Hans Weber Maschinenfabrik GmbH Extrudeuse à double vis avec filetage ondulée
WO2014183985A1 (fr) * 2013-05-14 2014-11-20 Frank Van Lück Procédé de fabrication d'un corps alvéolaire par extrusion et dispositif d'extrusion pour fabriquer un corps alvéolaire
US8998481B2 (en) 2012-08-16 2015-04-07 Hans Weber Maschinenfabrik Gmbh Double screw extruder
US10906215B2 (en) 2013-05-14 2021-02-02 Gneuss Gmbh Method for producing a foamed body by extrusion and extrusion device for producing a foamed body

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4025274A (en) * 1975-10-24 1977-05-24 Toyo Soda Manufacturing Co., Ltd. Apparatus and process for preparing thermoplastic resin composition
JPS5695662A (en) * 1979-12-29 1981-08-03 Matsushita Electric Works Ltd Construction of screw for extrusion molding machine
US5056925A (en) * 1990-06-01 1991-10-15 Scientific Process & Research, Inc. Extruder screws and method for accelerating melting in plasticating extruders
US6132077A (en) * 1998-05-26 2000-10-17 Fogarty; James D. Method of cooling a foam extrusion mixture to an extrudable temperature

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4025274A (en) * 1975-10-24 1977-05-24 Toyo Soda Manufacturing Co., Ltd. Apparatus and process for preparing thermoplastic resin composition
JPS5695662A (en) * 1979-12-29 1981-08-03 Matsushita Electric Works Ltd Construction of screw for extrusion molding machine
US5056925A (en) * 1990-06-01 1991-10-15 Scientific Process & Research, Inc. Extruder screws and method for accelerating melting in plasticating extruders
US6132077A (en) * 1998-05-26 2000-10-17 Fogarty; James D. Method of cooling a foam extrusion mixture to an extrudable temperature

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2535165A1 (fr) * 2011-06-16 2012-12-19 Hans Weber Maschinenfabrik GmbH Extrudeuse à double vis avec filetage ondulée
US8998481B2 (en) 2012-08-16 2015-04-07 Hans Weber Maschinenfabrik Gmbh Double screw extruder
WO2014183985A1 (fr) * 2013-05-14 2014-11-20 Frank Van Lück Procédé de fabrication d'un corps alvéolaire par extrusion et dispositif d'extrusion pour fabriquer un corps alvéolaire
US10906215B2 (en) 2013-05-14 2021-02-02 Gneuss Gmbh Method for producing a foamed body by extrusion and extrusion device for producing a foamed body

Also Published As

Publication number Publication date
NL1033085C2 (nl) 2008-06-20

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