DE102004010553B4 - screw machine - Google Patents

Abstract

Worm machine, - with a housing (1), - with mutually parallel axes (8, 9), each with the formation of gussets (10, 11) penetrating holes (6, 7) with bore walls (35, 36) with a Bore diameter (DB), - with concentric to the axes (8, 9) arranged in the same direction of rotation (17, 18) rotatably driven shafts (12, 13), - with non-rotatably mounted on the shafts (12, 13), meshing Helical elements (26, 27; 30, 31), each having a core (32) with a core diameter (Di) and at least one comb (33) with a comb diameter (DK), wherein between the at least one Comb (33) and the bore wall (35, 36) a comb play (SB) and between a comb (33) and an immediately adjacent core (32) a core game (Si) is formed, wherein the core Game (Si) is such that self-cleaning between the screw elements (26, 27, 30, 31) is achieved, and - with rotatably mounted on the shafts (12, 13), k Knet kneading elements (28, 29) with kneading discs (34), each having a core (38) with a core diameter (di) and at least one comb (37) with a comb diameter (dK), wherein between the at least one comb (37) and the bore wall (36) is formed a comb play (sb) and between a comb (37) and an immediately adjacent core (38) a core game (si), the Core game (si) is such that self-cleaning between the kneading elements (28, 29) is achieved, characterized in that the respective comb play (SB, sB) 2.0% to 10.0% of the bore Diameter (DB) is that the respective core clearance (Si, si) is at most 1.0% of the bore diameter (DB) and additional worm elements (26 ', 27', 30 ', 31') are provided are the support elements for the kneading elements (28, 29), wherein the comb play (S'B) of the additional screw elements (26 ', 27', 30 ', 31') opposite the bore Wall (35, 36) at most 1% of the Boh diameter (D'B).

Description

The invention relates to a screw machine, in particular an extruder, according to the preamble of claim 1.

In such screw machines, the treatment elements usually consist of screw elements and possibly also of kneading elements. Neighboring snail elements interlock, so they are meshed. In the same way, the kneading disks interlock. The core game between the screw land or comb of a screw element and the core of an adjacent screw element is very small; it is at most 1.0% of the bore diameter. This ensures that the screws are self-cleaning. The same applies to the rolling kneading discs. Usually, the comb play between the worm-combs or the combs of the kneading disks and the bore wall is in the range of at most 1.0% of the bore diameter.

The described customary embodiment can lead to excessive shear occurring in the materials to be treated or processed. Especially in the gusset area such extreme shearing can occur. In addition, there is an intensive diversion.

To overcome these problems, it is common in practice to grind the crests of the worm elements, thereby increasing the respective comb play between the worm crest and the bore wall. The consequence is that the intermeshing screw elements or kneading disks no longer work close-fitting, so they are no longer self-cleaning. In addition, the housings have been ground in the gusset area to increase the game at this point. Finally, the materials have been added to the materials as non-technical measures that reduce the shear in the material. All these measures are unsatisfactory.

From the DE 34 12 258 A1 is a screw machine of the generic type is known in which the kneading discs on the one hand have a relatively low core game and a relatively large comb game. As a result, the self-cleaning is to be maintained, but a maximum throughput with optimum melt homogeneity as possible can be achieved. In this case, it is also provided that by eccentric arrangement of kneading disks in each case a comb in the vicinity of the bore wall rotates and cleans them. The problems described above can be solved only partially.

A very similar screw machine is from the DE 30 14 643 A1 Known in which also zones of kneading disks can be combined with zones of approximately wall-scoring eccentrics. A stable operation is hereby only possible to a limited extent.

The invention is therefore based on the object, a screw machine of the generic type in such a way that it can be used for shear-sensitive materials without the self-cleaning of the treatment elements is lost.

This object is achieved by the features in claim 1. By the measures according to the invention it is achieved that on the one hand by a large comb game, that is, given by a relatively large game over the circumference of the respective bore wall and in particular in the gusset area a reduction in shear, but on the other hand by The small core game preserves the self-cleaning of the treatment elements. In addition to treatment elements with a large comb play, also screw elements with the conventional low comb play are used, which serve as support elements for the kneading elements.

Claim 2 represents an optimum range for the comb game again.

Further features, advantages and details of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing. It shows

1 an extruder in a schematic representation,

2 a horizontal part-longitudinal section through the extruder,

3 a vertical cross section through the extruder according to the section line III-III in 1 with the worm combs in the gusset area,

4 a vertical cross section through the extruder according to the section line IV-IV in 1 wherein a worm comb is in mesh with an adjacent worm core,

5 a vertical cross section through the extruder according to the section line VV in 1 showing the kneading elements

6 a horizontal partial longitudinal section through an extruder in opposite 2 slightly modified version,

7 a cross section through the extruder according to the section line VII-VII in 6 .

8th a horizontal partial longitudinal section through an extruder in one opposite the 2 and 6 slightly modified form and

9 a cross section according to the section line IX-IX in 8th ,

At the in 1 to 5 schematically illustrated screw machine is an extruder whose housing 1 from several housing sections 2 . 3 . 4 . 5 , so-called housing shots, is formed, of which only four are shown. In the case 1 are two intersecting holes 6 . 7 formed, whose axes 8th . 9 parallel to each other. In the penetration area of the holes 6 . 7 have the housing sections 2 to 5 so-called gusset 10 . 11 on. In the holes 6 . 7 are coaxial with the axes 8th . 9 waves 12 . 13 arranged by a drive motor 14 are drivable. Between the waves 12 . 13 and the engine 14 is a branching gearbox 15 arranged, in turn, between the engine 14 and the transmission 15 a clutch 16 is arranged. The waves 12 . 13 become in the same direction, ie in the same directions of rotation 17 . 18 driven.

On the gearbox 15 adjacent first housing section 2 is a material feed funnel 19 arranged, through the material to be processed or processed in the holes 6 . 7 can be entered. The material to be processed or processed is in a conveying direction 20 from the first housing section 2 until the last housing section 5 through the housing 1 promoted and leaves the extruder, for example, through a housing 1 final nozzle plate 21 , In a standard version, the extruder points in the conveying direction 20 one entry zone in a row 22 , a melting zone 23 , a kneading zone 24 and a pressure buildup zone 25 on.

On the waves formed as tooth waves 12 . 13 are - in the conveying direction 20 one behind the other - each paired identically formed screw elements in pairs 26 . 27 , Kneading elements 28 . 29 and again snail elements 30 . 31 each arranged as treatment elements. Both the snail elements 26 . 27 and 30 . 31 as well as the kneading elements 28 . 29 mesh with each other, so are formed tightly combing.

The snail elements 26 . 27 and 30 . 31 each have a worm core 32 with a core diameter D _i on. The snail elements 26 . 27 and 30 . 31 continue to have snail combs 33 on, which are arranged helically and have an outer diameter D _K. The holes 6 . 7 have a diameter D _B.

The kneading elements 28 . 29 have each paired kneading discs 34 on top of each hole wall 35 . 36 neighboring ridges 37 and flanks 38 exhibit. The kneading discs 34 have a comb diameter or outer diameter d _K and a flank or core diameter or inner diameter d _i . As the 3 and 4 on the one hand and 5 on the other hand, in the usual way is the cross section through the screw elements 26 . 27 and 30 . 31 on the one hand and through the kneading elements 28 . 29 shown identically.

The snail combs 33 have a comb game S _B opposite the bore wall 35 respectively 36 , for which applies: S _B = (D _B - D _K ) / 2. For the game S _B : 0.02 D _B ≦ S _B ≦ 0.1 D _B and preferably 0.03 D _B ≦ S _B ≦ 0.05 D _B. In other words, this means that the game is between hole wall 35 respectively 36 and snail comb 33 ie, the crest of the screw land is 2% to 10% and preferably from 3% to 5% of the hole diameter D _B.

In contrast, the core game S _{i is} between a snail comb 33 a snail element 28 respectively 30 and the snail's core 32 the associated screw element 29 respectively 31 much smaller. The following applies: S _i ≤ 0.01 D _B. In other words, this means that the core clearance S _{i is} at most 1% of the bore diameter D _B.

As 5 is removable, the information on the games S _B and S _i also apply to the kneading discs 34 , For the crest game s _B between crest 37 and bore wall 35 respectively 36 the following applies: s _B = (D _B -d _K ) / 2 and correspondingly 0.02 D _B ≦ s _B ≦ 0.1 D _B and preferably 0.03 D _B ≦ s _B ≦ 0.05 D _B. Similarly, for the core game s _i, between ridge 37 and flank or core 38 two pairs of mutually assigned kneading discs 34 s _i ≤ 0.01 D _B.

How vivid the 3 can be taken is when the snail combs 33 both associated snail elements 26 . 27 in the area of a gusset 10 are due to the relatively large comb game S _B significantly reduced the shear of the material to be treated or processed in this area. The same applies to the deflection of the material. On the other hand, the small comb-core clearance S _i ensures that the screw elements 26 . 27 self-cleaning, as they strip each other off. The same naturally applies to the kneading disks 34 ,

In the embodiment according to 6 and 7 are the kneading elements 28 . 29 identical to the previous embodiment. The snail elements 26 ' . 27 ' respectively 30 ' . 31 ' show only a slight comb play S ' _B opposite the bore wall 35 respectively 36 on, and a common game, for which: S ' _B ≤ 0.01 D _B. For the core game S _i , the previous one applies. In this embodiment, the screw elements have 26 ' . 27 ' respectively 30 ' . 31 ' at the same time the function of supporting elements for the kneading elements 28 . 29 , Of course, this can also be modified to the extent that any number of screw elements and / or kneading elements are formed in this form as support elements.

The embodiment according to 8th and 9 different from that after the 2 to 5 in that the snail elements 26 . 27 respectively 30 . 31 have been made into supporting elements that the bore diameter D ' _{B of} the bore wall 35 ' respectively 36 ' in the associated housing sections 3 ' . 5 ' has been reduced so that S ' _B ≦ 0.01 D' _B. For the rest, the above description applies.

Claims (3)

Worm machine, - with a housing ( 1 ), - with parallel axes ( 8th . 9 ), forming each other to form gussets ( 10 . 11 ) penetrating holes ( 6 . 7 ) with bore walls ( 35 . 36 ) with a bore diameter (D _B ), - with concentric to the axes ( 8th . 9 ), in the same direction of rotation ( 17 . 18 ) rotatable drivable shafts ( 12 . 13 ), - with rotation on the shafts ( 12 . 13 ), meshing snail elements ( 26 . 27 ; 30 . 31 ), each one core ( 32 ) with a core diameter (D _i ) and at least one comb ( 33 ) having a comb diameter (D _K ), wherein between the at least one comb ( 33 ) and the bore wall ( 35 . 36 ) a comb game (S _B ) and between a comb ( 33 ) and an immediately adjacent core ( 32 ), a core game (S _i ) is formed, wherein the core game (S _i ) is such that self-cleaning between the worm elements ( 26 . 27 ; 30 . 31 ), and - with rotation on the shafts ( 12 . 13 ), combing kneading elements ( 28 . 29 ) with kneading discs ( 34 ), each one core ( 38 ) having a core diameter (d _i ) and at least one comb ( 37 ) having a comb diameter (d _K ), wherein between the at least one comb ( 37 ) and the bore wall ( 36 ) a comb game (s _B ) and between a comb ( 37 ) and an immediately adjacent core ( 38 ) a core game (s _i ) is formed, wherein the core game (s _i ) is such that self-cleaning between the kneading elements ( 28 . 29 ), characterized in that the respective comb play (S _B , s _B ) is 2.0% to 10.0% of the bore diameter (D _B ) that the respective core game (S _i , s _i ) is at most 1.0% of the bore diameter (D _B ) and where additional screw elements ( 26 ' . 27 ' . 30 ' . 31 ' ) are provided, the support elements for the kneading elements ( 28 . 29 ), wherein the comb play (S ' _B ) of the additional screw elements ( 26 ' . 27 ' . 30 ' . 31 ' ) opposite the bore wall ( 35 . 36 ) is at most 1% of the bore diameter (D ' _B ). A screw machine according to claim 1, characterized in that the comb clearance (S _B , s _B ) is 3.0% to 5.0% of the bore diameter (D _B ). Screw machine according to claim 1, characterized in that screw elements ( 26 . 27 respectively. 30 . 31 ) are formed as support elements, that the bore diameter (D ' _B ) of the bore wall ( 35 ' respectively. 36 ' ) is reduced such that for the comb play (S ' _B ): S' _B ≤ 0.01 D ' _B.

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