DE1629749A1 - Extruder for thermoplastic resins - Google Patents

Description

Dipl-Ing. F.Weickmann, Dr. Ing. A / Weickmann, Dipl.-Ing, H. "Weickmann D1PL.-PHYS. Dr. K. Fincke Patent Attorneys 1 C ο q 7 / q

ΗΜΪ 8 MÜNCHEN 27, MDHLSTRASSE 22, CALL NUMBER 483921/22

Oasis 11 514-i ¹

THE DOW GHEMICAI COMPANY, Midland, Michigan / V. St. A.

Thermoplastic resin extruder

The invention relates to an improved extruder,

in particular, it relates to a screw extruder

a screw through which a heat exchange fluid can be passed.

When extruding synthetic thermoplastic resins, it is often desirable to use the liner of the extruder to heat and the screw with a heat exchange fluid equip to a relatively uniform temperature of the plastic melt and a rapid Heat placation of the introduced in di & HSohneckenpresse

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th, granulated material. It is often desirable for the screw of such a screw press to have at least two heat exchange zones, the first generally near the insert for the granulated material and the second generally near the outlet or die. By using two zones, it is possible to increase the heat supply to the granulated polymer in the first zone close to the inlet for the polymer or the melting zone and to obtain control of the temperature in the second zone, which is used to raise the polymer to be extruded Bring the extrusion temperature using a relatively short liner · Generally, internally heated and / or cooled extrusion screws are used in which a plug is friction fitted into the extruder screw so that the internal cavity of the screw is divided into two heat exchange zones. Suitable lines are provided for the circulation of the heat exchange fluid. Here, take considerable difficulties on _Λ if the position of the stopper or sub-divider must be changed. In general, the extruder must be dismantled

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i.e. the screw removed, the plug out of the screw drilled out and a new plug inserted. This method is expensive and time consuming and very special unfavorable for an experimental device where changes are often required »

The invention therefore creates an improved one Screw extruder with at least two heat exchange zones within the extruder screw, in which the zones can be changed without removing the screw from the device.

According to the invention, these results are most advantageous with an extruder for a synthetic, thermoplastic resin material obtained, which in operative connection a screw extruder having a sleeve with a first and a second end, means to the first end of the Liner is a synthetic thermoplastic resin material to feed, means to heat-plasticized, thermoplastic resin from the second end of the liner

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to let material escape, one arranged in the liner Screw that serves to remove the thermally plasticized, synthetic, thermoplastic resin material from the first end of the liner to promote its second end, and which has an inner cavity of generally cylindrical Has shape, a plug located within the cylindrical cavity, which the cavity divides into a first and a second heat exchange zone, the first heat exchange zone being close to the first ". End of the liner and the second heat exchange zone is arranged close to the second end of the liner, one Inlet and outlet conduits connected to the first heat exchange zone are in communication, and an inlet and an outlet conduit connected to the second heat exchange zone are in connection, which is characterized in that the plug is an expandable or, expandable plug which is constructed and arranged to be selectively into the wall of the cavity in the The worm can move in and out

Further features and advantages of the invention emerge from the following description in conjunction with FIG

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the attached drawing. In this mean:

1 shows a schematic representation of a cross section by an extruder according to the invention;

Pig. 2 shows a cross section through another embodiment an expandable stopper for use in the "device of Figure 1, and

3 shows two views of part of the plug

and 4 · ■■ · ■ "■ '

of Fig. 2.

Fig. 1 shows schematically a cross section of an extrusion device according to a preferred embodiment of the invention. The device is generally made by the reference number 10 denotes. The device 10 represents a screw extruder which has a bush 11 which has a first end 12 and a second end 13. The liner 11 defines a cylindrical Inner cavity 14 ° near the first end 12 of the Liner 11 is a loading opening 15, with a feed device 16 for the supply of the

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particulate synthetic thermoplastic resin material is bonded, and the feed port 15 establishes the connection between the feed device 16 and the inner cavity 14 in the liner 11. With the second end 13 of the liner 11 is an extrusion nozzle 18 in connection, which delimits an extrusion die 19, which in turn with the cavity H in connection stands. In the cavity 14 is a screw 21, which has a body part 22 with an outer, generally cylindrical surface 23 and one arranged around the cylindrical surface 23, helical Has squeeze surface 24. The body 22 defines an interior cavity 26 having a first end 28 which is generally arranged near the first end 12 of the liner 11 and a second end 29 disposed generally proximate to the extrusion die 18. A first Line 30 runs from a point outside of worm 21 into cavity 26 and ends in the sewing area second end 29. A second line 31 is arranged coaxially with the first line 30 and extends into the Cavity 26 and ends at a point between the two ends 28 and 29 of cavity 26. On the line

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an expandable plug assembly 33 is attached. The plug assembly 33 has a first or fixed body portion 34 that is rigidly attached to the conduit 31. The first body portion conforms generally to the inner cross-sectional shape of the cavity 26 and has a frustoconical, engaging surface 35. A second plug body part 36 is fastened on the line 31 such that it can be unscrewed. The body portion 36 also has a frusto-conical _t- engaged surface

37 on. The surfaces 35 and 37 are opposite one another and face outward. An expander — or sealing ring

38 is disposed between the engaging surfaces 35 and 37 and constructed so that _s if the part is screwed 36 into the line 31 in the appropriate direction, the body part 36 abuts the body portion 34 and the expander ring into sealing engagement with a! Portion of the screw 21 is pressed so that the cavity 26 is divided into a first and a second part, corresponding to the ends 28 and 29. A rotating device 40 is attached to the body part 36 towards the first end 28 of the cavity 26; and a third conduit 42 is coaxially attached around a part of the second conduit 31. The line 42

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has an inboard end 43 which engages means 44, which are arranged on it and can engage in the rotating device 40 of the body 36 · A fourth line 45 is arranged coaxially around third line 42. Line 45 ends near the first End 28 of cavity 26. A seal assembly 47 seals the fourth line 45 in the screw 21. A rotatable connection 48 e * ell * is in operative connection with the part of the conduit 45 which extends out of the cavity 26. A seal assembly 50 secures the fourth line 45 ah of the third line 42 in the vicinity of the rotatable connection 48, namely on that of the sealing arrangement 47 far side. A rotatable connection 41 is in operative connection with the third line at a location near the seal assembly 50, on that remote from the rotatable connection 48 located side. A sealing arrangement 52 holds the third conduit 42 in place on the second conduit 31 near the rotatable connection 51 and on the side remote from the sealing arrangement 50. A rotatable connection 53 is in operative engagement with the second conduit 31 at a location near the seal assembly

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52 and on the one remote from the rotatable connection 51 Page. A sealing arrangement 55 holds the second conduit 31 on the first conduit 30. A rotatable connection 56 is in operative engagement with the first line 30 at a location near the seal assembly 50 and at that remote from the rotatable connection 52 Page. The heat exchange fluid lines 58, 59, 60 and 61 lead to the rotatable connections 48, 51, 53 and 56, respectively, and are connected to them.

When operating the embodiment of the invention shown in FIG. 1, under normal operating conditions the body parts 36 and 34 of the plug 33 are pressed together by the engagement means 44 on the third conduit 42. The reason for this is that the. Expander or sealing ring 38 the cavity 26 in first or a second Part separates and seals against each other · The body part 36 on the line 31 by means of a screw thread is advantageous attached, the winding extends so that any slip caused by the friction of the rotatable connections caused the connection to strengthen instead of loosening it. When the position of the plug 33 is changed

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is to be, the sealing arrangement 50 is loosened, the third line 42 is pushed into the cavity 26 until the engagement means 44 engage in the rotating device of the body part 36. The body portion 36 is then rotated by means of the conduit 42 until the plug assembly can slide freely in the cavity 26. The second line 31 is then pushed axially into the desired position in the cavity 26, the third line 42 is then shifted again so that the engaging means 44 engage in the rotating device 40, and the plug arrangement 33 is again sealingly arranged in the cavity. The lines 30, 31, 42 and 45 are advantageously of such lengths that the plug 33 can slide back and forth within the desired limits. In this way, extrusion can take place in the desired manner, and a V / ärmeaustauschflüssigkeit may a first and a second region whose dimensions may easily be changed, and supplied therefrom äoge be subjected.

In Fig. 2, another embodiment of the Plug according to the invention shown, the general

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denoted by reference numeral 65. The plug 65 has a conduit 66 with one end 67 which carries an external thread 67 '. A shoulder part 68 is rigid on the Bath 67 of the line 66 attached. An engaging or cam part 69 is arranged next to the shoulder part 68. The cam part 69 has a generally frustoconical, outwardly facing surface 70 which engages an expandable part or an expander ring 71, which is arranged next to the surface 70 of the cam part 69. The expandable part has a radially outwardly extending surface 72 and a frusto-conical surface 73 which is for engagement with the Surface 70 is determined. A ring 75 is slidable on of conduit 66 and contacts radially outwardly extending surface 72. One for engagement The cavity determined portion 78 is located adjacent to the ring 75 and is operationally supported by a plurality of arms 79 ' engaged with this. The arms 79 engage in a frustoconical Cam surface 76 on ring 75 a. The frustoconical cam surface 76 serves to to press the arms 79 radially outward.

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Pig. Figure 3 shows a right to left view of member 78 leaving a plurality of outer slots or recognize recesses 80 which are intended for the engagement of a rotating device, not shown.

Fig. 4 shows the part 78 with an illustration of the arms 79. '

When operating the in the Pig. 2, 3 and 4, the conduit 66 is inserted into the cavity of FIG The extruder screw is brought and a second conduit is placed around conduit 66. The second line ends in noses that engage in the recesses 80 of the part 78. If you put the line 66 in the right direction rotates, the cam surface 76 presses the arms 79 outwardly so that they engage the wall of the extruder screw. at continued rotation of the line 66 presses the surface 69 of the expander or sealing ring'31 in sealing Engagement with the wall of the extruder chord. Third and fourth lines are in the Pig. 1 is also used.

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The sealing parts, for example the parts or 71, generally made of an elastic material. Such sealing parts are made of rubber or a synthetic resin such as polytetrafluoroethylene or similar elastic or deformable compositions which are resistant to the extrusion temperatures and the heat exchange fluid. at Using the arrangement according to the invention could easily alter the heat exchange zone within the extruder screw without having to disassemble the extruder was ο

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Claims (6)

PATENT CLAIMS 1.y Device for extrusion, a synthetic, thermoplastic resin material containing in operative connection a screw extruder, the screw of which has an internal cavity of cylindrical shape in which, a plug is located that divides the cavity into two heat exchange zones subdivided, characterized in that the plug is constructed to be expandable and is arranged so that he selectively, in the wall of the cavity in the screw moves in and out 2. Apparatus according to claim 1 _r , characterized in that the inlet and outlet lines of the second zone are arranged coaxially within the inlet and outlet lines of the first zone. 3. Device according to claim 2, characterized in that that the expandable plug is attached to one of the lines leading into the second zone. BATH 009885/1771 - 15 - 4. Apparatus according to claim. 5 »characterized, that one of the conduits of the first zone is adapted to engage the expandable plug to the Selectively move plugs into and out of the cavity wall. 5. Apparatus according to claim 4, characterized in that that a plurality of rotatable connections and seals connect between the inlet and outlet conduits the first and the second heat exchange zone "establish. 6. Apparatus according to claim 5, characterized in that that the expandable stopper has a fixed body part which is attached to a line of the two heat exchange zone is attached, a second body part is screwably attached to this conduit of the second heat exchange zone and a sealing ring is arranged between the body parts, which serves to fit into the inner wall of the screw cavity to engage while rotating the rotatably mounted body part. 009885/1771 - / 6 Blank page