DE4025960A1 - Versatile extruder screw - has set of rings discs or plates with mixing, distributing and shearing features which can be arranged at different angles to each other - Google Patents

Abstract

An extruder screw homogenises plasticated melt both thermally and mechanically and it revolves in a fixed barrel; it has mixing, distributing and shearing features on its circumference which have flights with alternating and different heights and intermediate troughs. These particular features are arranged on the circumference of rings, discs or plates forming one complete set; they are disposed successively or fixed relative to each other in different angular positions accordingly. ADVANTAGE - The screw can be varied in its layout to suit different requirements of mixing and shearing functions.

Description

The invention relates to a mixing part structure for Extruder screws for thermal and mechanical Homogenization of the melt plasticized in the extruder ze, which in a fixed screw barrel around runs and arranged with distributed around its circumference Mixing, distribution and shear elements is equipped, which alternately arranged adjacent to each other Bridges of different heights and turned in from these bounded hollows or chambers exist.

Such mixed part structures are designed so that they that section or zone of an extruder Form snail, which or which to mix and Extrudate shear is used. The mixer usually forms the last extruder element and is usually constructed so that existing ones Extruders can be equipped with this, provided whose torque is sufficient and the temperature of the Melt has not already reached a critical level.

The known mixers are of the generic type Mixed part building structure in its design to predetermined Coordinated purposes, d. H. you can regarding their mixing and shearing effects are not different Conditions are adjusted.

The invention is therefore based on the object Mixed part structure of the initially specified type to propose who has a changeable interpretation and therefore offers the opportunity to mix and shear kung to vary and to different requirements vote.

This object is achieved according to the invention in the first Line in that the mixing, distribution and shear elements depending on the circumference of module rings, disks or plates ten are, which form a kit and coaxial stringed together connectable as well relative to each other in different angles of rotation are fixable.

With such a modular construction of the mixing part Structure which the mixing, distribution and shear elements having module rings, disks or plates in vary their mutual assignment almost arbitrarily let it be obvious that there is an influence which enables mixing and shearing effects within wide limits becomes.

According to the invention it is provided that the mixing, Distribution and shear elements on the module rings and disks or plates of a kit a matching one Have circumferential distribution to be a problem Line up of module rings, disks or plates possible in several different angles of rotation lichen.

It is also provided according to the invention that module rings, -wheels or plates with just across them Circumferential directional mixing, distribution and shear elements can be assigned to module rings, disks or plates  are that with at least a partial scope running demarcation elements are occupied. With these means can then be determined on the circumference of the Structure the mixing, distribution and shear elements, so the webs and the troughs delimited by them or Chambers with regard to their effective length and position ren.

An important design feature for the invention Mixed part structure is also that the Abgren tongue elements at least over the distance range between two successive ones in the circumferential direction Mixing, distributing and shearing elements extend approximately in the way that they are the length of one between two webs trough or chamber at different heights limit.

The delimitation elements are also preferably in shape trained by footbridges. It has proven its worth the webs forming the delimitation elements increase the overall height that correspond to the overall height of the mixing, and higher webs belonging to shear elements Right.

It is provided according to the invention that the Boundary elements near an end face of Module ring, disc or plate and the Mixing, distributing and shearing elements only in Rich Connect to the other end face. On the other hand it is also important, for example, to use demarcation elements in the middle between the two end faces on the module ring, -to provide disc or plate, whereby this the mixing, distributing and connect the shear elements.  

A particularly simple embodiment for a mix Finally, part of the building structure is characterized by that the mixing, distributing and shearing elements are parallel extend to the screw axis while the delimitation elements run across this.

A mixed part structure according to the invention can be using only three different designs Form the module rings, disks or plates len, simply by not only lined up as desired, but also in the appropriate rotation angle position to each other to be brought.

Based on the drawing, the subject matter of the invention explained below using an exemplary embodiment. It demonstrate

Fig. 1 in a schematically simplified side view of a mixed partial structure in its structurally simplest embodiment,

Fig. 2 shows a section along the line II-II in Fig. 1, while the

Fig. 3 to 5 each in one of Fig. 1 corre sponding side view three modified compared to Fig. 1, more complex versions of a mixing part building.

If plasticizing extruders are equipped with a mixing part, then this is usually arranged so that it works as the last extruder element. If a dynamic mixer is used, it has a stationary mixing part structure 1 and a rotating mixing part structure 2 . The stationary mixer part 1 connects coaxially to the extruder housing and receives the rotating mixer part 2 , which is arranged in a coaxial extension of the extruder screw and rotates together with it.

The mixer 3 formed by the stationary mixing part structure 1 and by the rotating mixing part structure 2 , as can be seen in FIG. 2, belongs to that class which is based exclusively on a modification of the rotating mixing part structure coupled to the extruder screw 2 is based, which is therefore only to be seen on its own in FIGS. 1 and 3 to 5.

However, it is not excluded to use a rotating mixing part structure 2 of the design shown in the drawing - in deviation from FIG. 2 - also in a mixer of the class which is characterized by modification of the screw and cylinder.

In any case, it is the characteristic feature of the rotating mixing part structure according to FIGS. 1 and 3 to 5 that it has a modular structure in that it consists of a larger number of module rings, disks or plates 4 a, 4 b, 4 c is formed, which together form a kit and can be coaxially lined up and connected together. It is also important, however, that the module rings, disks or plates 4 a, 4 b, 4 c combined in each case to form the rotating mixing part structure 2 are fixable relative to one another also in different angles of rotation in order to end different modifications of the rotie To allow mixed part structure 2 , as can be clearly seen from FIGS. 1 and 3 to 5 of the drawings.

The apparent from Fig. 1 of the drawing modification of the rotating mixing part structure 2 is composed of nine module rings, disks or plates 4 a and 4 b lined up together, in such a way that seven module rings 4 a are lined up directly, and that each End of the rotating mixing part structure 2 is determined by a module ring or a module disk or plate 4 b.

The modification of the rotating mixing part structure 2 shown in FIG. 3 of the drawing in turn comprises nine module rings, disks or plates 4 a to 4 c lined up, whereby six module rings, disks or plates 4 a, two module rings, disks or -plat ten 4 b and a module ring or a module disc or plate 4 c are used.

The module rings, disks or plates 4 b here again form the ends of the rotating mixing part construction body 2 , while the module ring or the module disc or plate 4 c is provided as a central portion of the rotating mixing part construction body 2 , to which Connect three module rings, disks or plates 4 a on each side.

In the modification of a rotating mixing part structure 2 shown in FIG. 4 of the drawing, five module rings, disks or plates 4 a, two module rings, disks or plates 4 b and also two module rings, disks or plates 4 c put into use. This is done in such a way that - seen from right to left - on a module ring or module disc or plate 4 b, first two module rings, discs or plates 4 a, then a module ring or module disc or plate 4 c, further in turn two module rings, discs or plates 4 a, a module ring or a module disc or plate 4 c, further a module ring or a module disc or plate 4 a and finally in a module ring or a module disc or plate 4 b are lined up.

In Fig. 5 of the drawing is finally a Modi fication of the rotating mixing part structure 2 , the four module rings, disks or plates 4 a, three module rings, disks or plates 4 c and two module rings, disks or plates 4 b used.

The arrangement here is such that the two module rings, disks or plates 4 b in turn form the two ends of the rotating mixing part structure 2 and that between them then individual module rings, disks or plates 4 a and 4 in alternating succession c are placed next to each other.

Each of the module rings 4 a, 4 b and 4 c is equipped with mixing, distributing and shearing elements arranged around its circumference, which consist of mutually adjacent webs 5 a and 5 b and between these troughs or chambers 6 .

The webs 5 a have, as can be seen in particular from FIG. 2 of the drawing, a greater profile height than the webs 5 b, so that their end faces rotate directly close to the inner circumference of the stationary mixing part structure 1 . On the other hand, the end faces of the webs 5 b each lie at a radial distance from the inner circumference of the stationary mixing part structure 1 and thereby cause the formation of a gap 7 with respect to the inner circumference of the stationary mixing part structure 1 .

It can be seen from Fig. 2 but also that the profile width of the webs 5 is a larger sized b than the profile width of the webs 5.

The webs 5 a and 5 b forming the mixing, distribution and shear elements are arranged on the module rings, disks or plates 4 a, 4 b and 4 c with a corresponding distribution in the circumferential direction. In this case four webs 5a are shown in Fig. 2 each with mutual angular intervals of 90 ° are provided and four fins 5 have b to one another in each case at an angular distance of 90 °. There is also an angular distance of 45 ° between adjacent webs 5 a and 5 b.

While the module rings, disks or plates 4 a are only equipped with webs 5 a and 5 b which extend over their entire thickness and parallel to their longitudinal axis, the module rings, disks or plates 4 b have additional delimitation webs 8 and the module rings, disks or plates 4 c on additional delimitation webs 9 .

The delimitation webs 8 and 9 are located just if on the circumference of the module rings, disks or plates 4 b and 4 c. However, they run transversely to the webs 5 a and 5 b, that is to say parallel to the main plane of the module rings, disks or plates 4 b and 4 c, and in each case only over part of the circumference, the distance between two successive webs 5 a and 5 b extends. Each of the delimitation webs 8 and 9 determines an end region for the trough 6 located between the successive webs 5 a and 5 b and for this purpose has a profile height which corresponds in each case to the profile height for the webs 5 a.

It can be seen from the drawing that the Abgren zungsstege 8 on the module rings, disks or plates 4 b are in the vicinity of an end face thereof and the webs 5 a and 5 b join it only in the direction of the other end face.

In contrast, the delimitation webs 9 on the module rings, disks or plates 4 c are formed approximately in the middle between their two end surfaces and this is followed by the webs 5 a and 5 b to both end surfaces. It is important to note that the webs 5 a and 5 b extending from the boundary web 9 to both end surfaces are offset in the circumferential direction so that where a web 5 a extends to one end surface, the other end surface a web 5 b extends and vice versa. The arrangement of the webs 5 a and 5 b is provided on the module rings, disks or plates 4 c, that is, in the circumferential direction 45 ° against each other rotates ver.

All module rings, disks or plates 4 a, 4 b and 4 c are designed so that they can be brought into different angles of rotation relative to one another and fixed therein. It is provided that the different rotational angular positions correspond to the angular distances between the successive webs 5 a and 5 b, that is to say each rotation step of 45 ° is possible. For the purpose of mutual fixation of module rings, disks or plates 4 a, 4 b and 4 c lined up, these can be equipped with fitting bores 10 into which corresponding dowel pins can be used as coupling elements.

A comparison of the drawing figures 1 and 3 to 5 makes clear what multitude of modification possibilities for the assembly of the rotating mixing part structure 2 are created in that a kit of three different module rings, disks or plates 4 a, 4 b and 4 c can be used. Not only the position of the webs 5 a and 5 b and the troughs 6 in the circumferential direction, but also their length in the axial direction of the rotating mixing part structure 2 can vary within wide limits. Using only a few different standard parts, rotating mixing part building bodies 2 can therefore be created which meet a wide variety of requirements with regard to the mixing and shearing of an extrudate.

So when looking at the drawing figures 1 and 3 to 5 it is readily apparent that the overflow gaps between two adjacent troughs or chambers 6 are kept free in the area of the low profile height webs 5 b towards the inner circumference of the stationary mixing part structure 1 be able to obtain variable displacement or staggering within wide limits in order to obtain the most favorable flow path of the melt for the respective application. The mixing and shearing action on the extrudate can thus be easily adapted to the most varied of requirements.

Claims (8)

1. Mixing part structure for extruder screws for thermal and mechanical homogenization of the extrusion of the plasticized melt, which rotates in a stationary screw cylinder and is equipped with mixing, distributing and shearing elements distributed around its circumference, which are arranged alternately adjacent to one another Webs of different heights and troughs or chambers defined by them exist, characterized in that the mixing, distributing and shearing elements ( 5 a, 5 b, 6 ) are located on the circumference of module rings, disks or plates ( 4 a, 4 b, 4 c) are located, which form a kit and can be connected coaxially with one another and can also be fixed relative to one another in different angles of rotation. 2. Mixing part structure according to claim 1, characterized in that the mixing, distribution and shearing elements ( 5 a, 5 b, 6 ) on the module rings, disks or plates ( 4 a to 4 c) of a kit a matching Have circumferential distribution. 3. Mixing part structure according to one of claims 1 and 2, characterized in that module rings, disks or plates ( 4 a) with only transverse to their circumferential direction oriented mixing, distributing and shearing elements ( 5 a, 5 b, 6 ) Module rings, disks or plates ( 4 b and 4 c) can be assigned, which are also equipped with delimiting elements ( 8 and 9 ) running at least over a partial circumference. 4. Mixing part structure according to one of claims 1 to 3, characterized in that the delimitation elements ( 8 and 9 ) are at least over the distance region ( 6 ) between two consecutive in the circumferential direction mixing, distributing and shearing elements ( 5 a and 5th b) extend. 5. mixing part structure according to one of claims 1 to 4, characterized in that the delimitation elements ( 8 ) are in the vicinity of an end face of the module ring, disk or plate ( 4 b) and the mixing, distribution and shear elements Only connect te ( 5 a and 5 b) towards the other end face. 6. Mixing part structure according to one of claims 1 to 4, characterized in that the delimitation elements ( 9 ) sit approximately centrally between the two end faces on the module ring, disk or plate ( 4 c) and that each of these faces towards both end faces connect the mixing, distributing and shearing elements ( 5 a and 5 b). 7. mixing part structure according to claim 6, characterized in that the respective extending to the two end faces mixing, distributing and shearing elements ( 5 a and 5 b) one to another by a pitch ( 5 a / 5 b) rotated against each other Have arrangement. 8. mixing part structure according to one of claims 1 to 7, characterized in that the mixing, distributing and shearing elements ( 5 a, 5 b) extend parallel to the screw axis, while the delimitation elements ( 8 and 9 ) ver transversely thereto to run.