Apparatus for continuously melting and mixing plastics.

The invention relates to an apparatus for continuously melting and mixing plastic materials by means of several axially parallel screw of the same pitch direction, which engage almost fit and are driven in the same direction.

Such a device is known from DE-OS 2003 593rd The special feature of this device is that in each flighting a this across exciting sealing web is placed, whose outer diameter corresponds to that of the screw, which-the worm gear is closed off in its direction of flow. By this sealing web a strong jam is generated in the screw channel in question, which should trigger a plasticizing of the plastic to be processed. to give the necessary space in order to seal land in the area of ​​the adjacent screw, owns the adjacent screw at the moving past at screw rotation at sealing web site a corresponding recess, which interrupts the feed edge of the adjacent screw, whereby the transported in an auger material the possibility of evasion is placed in an adjacent screw flight. Therefore, the areas are the locations at which substantially takes place on plastics against the action of the webs and the recesses.

The invention is based on the object to be consecutive along the individual screw consecutive points of the action on the plastic in the sense of melting and mixing relatively close to zu'verteilen the processing of the plastic evenly as possible over the relevant length of the screw and on thus, to obtain a more homogeneous product. Moreover, these bodies should be designed so that each exposure is practically in the same way, so that the existing in the known device effect the particularly strong influence in the lands and the contrast much weaker action by the recesses, so an alternate differently strong action is avoided.

According to the invention this is achieved in that each screw is divided into successive slices, each of which pairs have the neighboring of screw to screw washers same thickness, wherein along each screw from pair of inputs to the next pair of discs each at an angle _; turns are, within a pair each by the same angle in the same direction, and that in the region of the freed up by the rotation end side surfaces of the disks, these surfaces have centric paragraphs of such height and width, that the ends of the relevant dates together are moved past at Schnekkendrehung.

As a rule, such devices with several axially parallel screws are designed with multiple threads, resulting from the rotation of the discs to each other in circumferential direction of the coefficient corresponding number of the rotation vacated-end side surfaces and, consequently, arranged in the region of these surfaces paragraphs, by the to processed plastic is in its flow disturbed and split along the shear edge of a flight, resulting in intimate mixing of these action points. The effects which occur the supervisor thaw and shearing of the material to be processed also lead to corresponding heating and thus serve the Plastifizierun_e of the material. The action sites are all of identical design, so that in each case on the disk pairs, a uniform exposure is achieved in the plastic.

It should also be made in this connection to another prior art, represented by the DE-OS 25 50 969. In this apparatus for homogenizing plastics is disclosed with two intermeshing screw shafts, when connected to the screw portions of areas with Vieleckscheiben. Due to the effect of Vieleckscheiben material to be processed is passed from one wave to the other back and forth. The individual Vieleckscheiben are turned against each other longitudinally on each shaft, so that there are overlapping areas of Vieleckscheiben from wave to wave in the rotation of the shafts. To achieve an effect on the material to be processed in these overlap regions, have the Vieleckscheiben in the overlap regions reduced width, so that there are gaps between the meshing Vieleckscheiben. In these columns, then finds the key action rather than the material to be processed. However, this prior art is not a guide to the apparatus of the invention, since with the interlocking of screw quite different conditions are different from the interlocking of Vieleckscheiben. The intermeshing screws are much unübersichtlichere ratios than before meshing Vieleckscheiben. not visible In the former ist.nämlich readily apparent that the costs of their division into slices and their mutual rotation overlapping areas are not mutually interfere so that in this way a rotation of the screw shafts is impossible. Surprisingly, it has been found, however, that even snails are divisible into mutually rotated disks, wherein a substantial effect, the auger feed effect, which practically does not exist in the twisted Vieleckscheiben, maintained, in addition to this effect the shearing and mixing action due to the rotation of the discs vacated front side faces should subordinate its heels and even not the expected one in intermeshing screws, pronounced occurs handover effect, which is due to the fact that each flow channel of each screw constrictions and thus jams the flow of material result that due to the relative rotation of the discs are.

When the device so formed that the discs have along the worm decreasing thickness, then advantageously results in that the through-funded material which thickens due to the melting process, is increasingly being subjected to by the vacated front side faces a processing, as these front side faces then dense consecutive.

It is also possible to choose the thickness of the discs along the screw so that a thinner, and then again a thicker etc. followed by a thicker disc. This has the effect that alternately different closely spaced exposure jobs will be created, which is for many purposes beneficial.

It is also possible to give the successive discs each have different screw pitches. This can be influenced so that a thus possibly given axis parallelism of the succession of the action points is avoided the succession of the action points. In such an unequal massive torque would result from rotation of the shafts.

In order to ensure the free movement past each of the faces at screw rotation, the radial distance of the paragraphs of the screw outer surface must be at least equal to half the pitch. Sinking height should be understood in this context, the radial distance between the outer screw surface and bottom of the screw.

Cheap ratios for the shearing and mixing action arise especially when the axial width of paragraphs at most equal to the pitch.

To any rotation of the wheels to adjust to each other, to the worm builds appropriately on so that its wheels on a it passes through the screw axis can be placed selectively in different angular positions. During assembly, then one has the possibility of adjusting each desired angular position. This angular position can then subsequently be altered disassembly of discs and screw axis.

Exemplary embodiments are illustrated in the figures. Show it:<ul><li>Fig. 1, the device with two axially parallel screws, which are constructed in their middle region of the same discs,</li><li>FIG. 2 is a disk pair in side view,</li><li>Fig. 3, the same pulley pair to further rotation of both screws at an angle of 60 °,</li><li>Fig.% A development of the outer surface of the screw according to FIG. 1,</li><li>Fig. 5 shows a modification of the apparatus of FIG. 1 with slices decreasing thickness and different screw pitch,</li><li>Fig. 6 shows a modification of the apparatus of FIG. 1 with alternating thick slices.</li></ul>

The device shown in FIG. 1 shows the two axially parallel screw 1 and 2, which engage almost fit and are driven in the same direction by a known, not shown here gearbox. Also not shown 1 in Fig., The housing having the two screws 1 and 2 as closely encloses in a known manner in that the housing inner wall, the screw ridges 3, 3 ', 3 "enclosing with a small clearance. The arrangement of the housing is from the Fig. 2 can be seen. the two screws 1 and 2 are each divided into three sections 4a, 5a and 6a and 4b, 5b and 6b. the areas form 4a / 4b and 6a / 6b pure funding areas, while in itself the regions 5a and 5b to the melting and mixing zones is that are each composed of five discs 7a and 7b. the discs 7a and 7b respectively include screw portions corresponding to the screw 4a / 4b and 6a / 6b. When the discs 7a and would be 7b so joined together and connected to the portions 4a / 4b and 6a / 6b, that the screw flights would pass continuously into each other without joint, then consistently would result in each case a screw, as shown in the areas 4a / 4b and 6a / 6b is. In the area 5a / 5b, the individual wheels 7a and 7b are progressively turned against each other, in each case at an angle of 30 °. One can see this twisting particularly clear at the point of transition from region 4 to the plate 7a, where the crests respective 3 'and 3' 'are not going to play. For the shock Tellen between the other disks 7a2 - 7a5 or 7b1 - 7b5 and the connection point of the discs 7a5 / 7b5 to screw the portions 6a / 6b, the same applies. Two slices of 7a1 / 7b1 etc. thereby form a couple whose two discs are rotated 7al or 7b1 in each case by the same angle, so that engage the worm in question fits within a pair. It is therefore retained the conveying effect of the screw in the region of each pair.

FIG. 2 shows the arrangement of FIG. 1 in section along the line II-II. In addition 2, the housing 8 is shown in FIG. Plotted, which surrounds the two screw, of which only the discs 7a2 and 7b2 are visible in Figure 2 with a small clearance. Of the two discs 7a2 and 7b2 whose front side faces 9a and 9b are visible, with which the two discs have a 7a2 and 7b2 on the discs 7al and abut 7b1. The two discs 7a2 and 7b2 have, moreover, the two openings 10 a and 10b is applied to the function discussed in more detail below. The rotation of the two discs 7a2 and 7b2, which is carried out by the same angle in the same sense, has with respect to the engagement of the two discs formed on this screw no effect. The two screws engage nearly match still engage each other when the two discs are 7a2 and 7b2 driven in the same direction according to requirement. To this extent are relative to the two discs 7a2 and 7b2, the same conditions as before with respect to the screw in the regions 4a and 4b and 6a and 6b. Since the discs 7a1 / 7b1 etc. 9a from pair to pair with no gap with their end faces and 9b abut each other, as would at rotation of the screw 1 and 2, 9a and 9b ending ridges 3a and 3b in abutting contact slide past in the faces to each other, which would inevitably lead to a clashing of these ends. For this reason, the paragraphs are lla, 12a and 13a and llb, 12b and 13b are provided, through which said end faces of the ridges 3a and 3b in an axial direction opposite the end faces 9a and are set back 9b. Paragraphs lla, 12a, 13a and llb, 12b, 13b thus form as shown in FIG. 2, the visible faces of the ridges 3a and 3b, which as a result of the respective end faces of each adjacent pair of discs (with respect to the discs 7a2 and 7b2 , the discs 7a and 7b at a distance past each other, corresponding to the width 14 of a paragraph (see disc 7al in Fig. 1). This simple width as the distance of sliding past arises reason that each lla paragraphs, 12a, 13a respectively . llb, 12b, 13b and the other pass in FIG. 1 marked paragraphs as they pass on the opposite wheel of the subsequent pair on the front side surface of the pair, but not on a shoulder of this disc.

In FIG. 3, the pair shown in Fig. 2 of the discs is 7a2 and 7b2 shown in a further operating phase, namely, by further rotation of the two screws at an angle of 60 °.

Figs. 2 and 3 can be read, that the respective in a worm gear transported material when it reaches the area in which the two screws mesh with each other, is deflected by a screw to the other, which the known function of the known twin-screw described in the opening is. This produces at the crossing point by the deflection of the flow direction of the material, a traffic jam, the through presses the material by the by the heels 11a, 12a and 13a or 11b, 12b and 13b, etc., so that at this point, a shear of the material to be processed occurs. In addition, and so played each snail is disturbed in its continuous course through the rotation of the wheels 7a1 etc. or 7b1, which naturally disturbs the flow of the transported by the screw material in the same manner and to the desired congestion and so performs mixing of the material.

is still apparent from Fig. 2, that the radial distance 30 of the heels 11a, 12a, 13a or 11b, 12b, 13b of the ridges 3a and 3b, is slightly larger. than half the pitch 31 Definitely need this distance 30 be equal to or greater than half the pitch of 31, so that the front side faces of two staggered not at each another shaft arranged disc while rotating the shafts touch.

From Figs. 1 and 2 also show that the drawn in FIG. 1 axial width 14 of paragraph 13 (and the other paragraphs) maximum of the pitch 31 corresponds. This leads according to experience at particularly favorable mix results. As is apparent from FIGS. 2 and 3, possess the discs 7a2 and 7b2 (and of course in Fig continue. 1 slices shown) has an internal toothing with teeth 32 and tooth spaces 33. With this inner toothing 32/33 the discs are rotationally secure manner on with corresponding teeth postponed provided shafts on which they then each rotated to-desired angle can be placed. This makes it possible that the twist angle from disk to disk along a screw can be adjusted optionally, at least by the angle of the pitch of the toothing 32/33.

In FIG. 4 is a developed view of the illustration of Fig. 1 is shown. The line 15 represents the edge 16 of the housing 8 in Fig. 2. By this edge is then carried out from the processing using the two screws 1 and 2 and on the basis of Fig. 2 to the right and left up to the edge 16 opposite edge 17 of the housing 8, the lines 18 and 19, the edge in Figure 4 represent the 17th Moreover, the analogy between the representation of FIG. 4 and the representations of FIGS. 2 and 3 by using the same reference numerals is made.

., In the apparatus shown in Figure 5 is two screws 1 and 2 with slices 20a - 23a and 2Ob - 23b decreasing thickness, also having individual discs have a different screw pitch. The discs 20a and 22a, and 22b have 2ob against the discs 21a and 23a or 21b and 23b to the greater slope. Otherwise, the function of the two screws 1 and 2 having the above-mentioned disks, the same as in the arrangement of Fig. 1. The different slice thickness is achieved that in the way of the thicker slices to the thinner slices at more frequent intervals, the material to the action by the above-mentioned sections (Einwirkungs filters) is subjected, so that with increasing compression of the material in the way along the screw also an increasingly intense action is achieved. By each selected slope of the effect is thereby achieved that do not reach the turning of the screws 1 and 2, the action points forming portions in greater numbers at the same time in the meshing area of ​​the screws 1 and 2, which currently a considerable burden on the worm and thus necessarily a would cause increase in torque. Hereby is achieved that the torque over a full rotation of the worm 360⁰ practically can remain the same.

In FIG. 6, a device is shown, are provided in the discs of alternating thickness, said disks ₂4a / 24b, 26a / 26b and 28a / 28b against the discs 25a / 25b; and 27a / 27b are substantially thicker. Otherwise, the function of this device is the same as in the apparatus of FIG. 1. The use of discs of varying thickness results in the effect that it were gradually occurs a particularly intense effect on the material, whereupon then in the area of ​​thicker slices a area less intensive machining results.

It should be noted that in all embodiments described above, the action points forming portions can be such that they are not so do not lie in their axial succession on a line parallel to the axis. In such a situation, the effect would in fact shown that a large number of action points during rotation of the screw in the region of the meshing of the screw passes, which at the moment in question, a considerable increase in torque would stop, since in this case the worm particularly be heavily loaded would. To avoid this, the portions are conveniently placed so that they do not lie parallel to the axis.

The division described above the worm in consecutive slices is applicable to both devices with two and more screws, both in such a way that the screw axes of a plane, at the apices of a triangle or V-shaped.