SK38193A3 - Device for rubber grinding - Google Patents

Abstract

The invention relates to a device for comminuting rubber, consisting of a screw extruder and a grinder fed by the screw extruder and having two grinding discs which enclose a conical grinding gap between them, of which one is provided with a central inlet for the material to be ground and of which at least one is rotationally driven. The object of the present invention is, using simple means with reduced energy outlay, to comminute rubber into a floury powder. The invention consists in the extruder screw and the grinding discs being arranged on the same shaft and the annular gap between the extruder screw and the extruder barrel continuing directly into the annular gap between the grinding discs.

Description

Rubber grinding equipment.

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for grinding pieces of rubber comprising a screw extruder, a grinding machine supplied therewith, with two grinding wheels, which grip a conical grinding space therebetween, one of which is equipped with powered by.

BACKGROUND OF THE INVENTION

Such a device became known from DD 265 855 A1. In this known apparatus, the grinding apparatus with two discs forming a conical grinding gap is connected to the extruder via a radial outlet pipe. Several processing zones have been achieved in the extruder by differently shaping the various sections of the screw. This is necessary because the rubber is very difficult to grind.

Because the rubber is inhomogeneous in many respects: By varying the exposure to the sun and varying the load when using an automobile tire, as well as due to different age, the rubber to be treated has aged differently. The pieces of rubber waste have heavily aged parts that are relatively easy to release and relatively easy to grind. Other, less aged parts, on the other hand, still have considerable elastic properties and cannot be pulverized either at all or only extremely difficult to grind. Since the heavily aged parts of the splole with the little aged parts are most often contained in a single piece, there are particular processing difficulties. These are further increased by the presence in the rubber waste of foreign substances in the form of metal parts or cord threads or other foreign bodies which cannot be separated prior to grinding because they are partially surrounded by rubber or the rubber is partially vulcanized on them.

However, rubber waste is also produced during manufacture, for example by some manufacturing or mixing errors, or when confusing goods are produced using unsuitable mixtures.

For this reason, DD 265 855 A1 envisages a device for separating the granular stock from the pulverized stock and the granular stock is fed back to the inlet funnel of the extruder. In this way, the poorly aged grains of rubber will pass through the device several times. However, this is not the only drawback of this device, the drawbacks are also that the delivery to the disk comminution apparatus is associated with considerable difficulties, since the material entering the coherent stream with full cross section to the comminution apparatus entry has to be divided into an annular stream. In its own comminution apparatus, the material, due to its elasticity and its cuddly properties, generates considerable difficulty in converting it to a dust state, which is only partially accomplished, the granular residue being fed to the comminution apparatus repeatedly.

SUMMARY OF THE INVENTION

The present invention seeks to avoid shortcomings in the prior art. The present invention is based on two findings which result in a substantially improved grinding process:

Firstly, it is recognized that it is not necessary to first transform the annular stream into a full cross-sectional stream and then divide it again into an annular stream without doing the grinding work. Secondly, it is recognized that rubber grains, pieces and chips with considerable elastic properties lose elasticity when the comminution device engages them at a very high speed.

The object of the present invention is to spread with a simple means and with reduced energy consumption the rubber waste into a powder as fine as a meal.

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The invention is that the screw extruder and the grinding discs. The devices are arranged concentrically on the same geometric axis and that the annular gap between the extruder screw and the extruder cylinder has a straight continuation into the annular gap between the grinding wheels.

In this way, the rubber material supplied by the extruder continues in the annular stream directly into the annular stream in the gap between the grinding wheels. This ensures a completely continuous flow of material, the grinding wheel is regularly supplied and can therefore work in the best possible way.

In this case, it is expedient if the end piece of the screw extends into or passes through the grinding wheels. The grinding wheel can be mounted radially on the end piece of the screw, which results in a lower speed for the rolling bearing than when the rotating grinding wheel is mounted on the fixed part, but higher differential speeds are easier to achieve, for example, in counter-rotating operation.

It is expedient if the rotating grinding wheel is driven, preferably separately, in the same sense or in the opposite direction, and it is even preferred that a higher number of revolutions is selected. Because the rubber itself, still elastic, can be pulverized at high rotational speed of the grinding wheels, since the elastic properties of the rubber are considerably lower at a high stress frequency than at a low frequency.

In order to compensate for the wear condition of the grinding wheels and to set the grinding gap to optimal values, it is expedient if the means for moving one grinding wheel against the other are envisaged.

Equipping the extruder screw within its grinding discs with a reciprocating thread constitutes the bearing protection at the end of the extruder screw while improving the transfer of material from the extruder screw to the grinding gap.

The passage of the extruded material into the gap between the grinding wheels is facilitated if the gap between the grinding wheels is preferably gradually tapered at least in the inlet region. This gap shape also promotes gradual grinding of the rubber pieces.

Furthermore, it is advantageous for the drawing-in and grinding of the treated rubber pieces if at least one grinding wheel in the drawing-in area is provided with ribs which cut and cut the rubber pieces.

The construction of the device according to the invention can be designed in such a way that the common geometric axis of the screw and the grinding wheels is mounted horizontally and that a radial hopper in the screw extruder is foreseen. This horizontal embodiment will be preferred wherever a screw extruder is already available and to which a comminution housing containing both grinding wheels is attached.

However, the grinding discs are supported by another design in which the common axis of the screw and the grinding discs is vertically arranged and the hopper arranged at an angle is assumed on a vertically standing extruder.

However, the vertical arrangement of the device according to the invention can be realized in such a way that the common geometric axis of the screw and the grinding wheels is vertically arranged so that the screw passes through the grinding wheels axially and extends through its carriage into the vertically standing hopper. Here, the advantage of a light bearing of the rotating grinding wheel is combined with the advantage of a low shape.

In this embodiment, it is furthermore advantageous if the worms in the region of the hopper are equipped with a raking device which prevents the formation of bridges in the hopper space.

The grinding effect can be enhanced by placing the lattice before passing the extrusion path from the screw to the grinding disc gap, with preferably a fast-change device or a fast-acting cleaning device, with blades narrow in a direction perpendicular to the extrusion direction but deep in the extrusion direction. At the same time, the lattice can prevent thicker metal parts from advancing, which could damage the grinding equipment. Therefore, it is advantageous if this lattice is replaceable and is occasionally replaced during operation to remove coarse metal particles.

Overview of the figures in the drawing

The essence of the present invention is explained in more detail below, by way of example of embodiment shown in the drawing. The pictures show:

1 shows the device in a horizontal configuration, FIG. 2 the device in a vertical configuration with an inclined feed hopper, FIG. 3 a vertical arrangement with a vertically converted hopper.

Examples

A screw 3 is rotated in the roller of the extruder 1 with the feeding hopper 2, which can be equipped with differently shaped sections of the screw for reasons of better feeding of material but also for grinding of the feed material. The roll 4 is followed by a comminution device housing 4, which comprises grinding discs 5, 6. In the illustrated embodiment, the grinding disc is stationary, can be mounted and exchangeable in the housing 4, but can also be manufactured in one piece with the housing 4. the grinding wheel 6 rotates. A screw 2 passes through it and is radially supported thereon. Within the central bore of the grinding disc 6, not only bearings are arranged for radially receiving the grinding disc 6. The screw 2 also has a thread not shown for the reciprocating movement of the material within this gap.

Two separate drives have the advantage that different speeds can be set independently. However, it is also possible to drive both the screw and the rotating grinding disc 6 with one and the same motor 7. This drives the screw 3 formed at one end as a shaft 8 directly through the upstream gearbox 9 to which the gearbox 10 is connected. 8, in which a gearwheel is mounted in the gearbox housing 10, which drives a hollow shaft 12 which is connected to the grinding disc 6 via a large-speed gearbox 10. On the rear side of the grinding disc 6, axial adjusting means 12 act, by which the gap between the grinding wheels 5, 6 can be adjusted.

Suitably, in the feed area of the grinding discs 5, ribs 13 are provided on at least one grinding disc.

The gap between the grinding wheels is surrounded on the outlet side by a chamber 14 through which a stream of air flows through the line 15 to the dust separator. The coarse grit passes through the separator tube 18, where the grit is sorted according to the size of the time. Figure 2 shows a vertical embodiment of the device according to the invention: The same parts are designated with the same reference numerals here. The drive of the screw 3 secures dust 17 on the side.

lation

A geared motor 19 is mounted on the head. The inclined feeding hopper 20 is supplied with pieces of old rubber by the extruder. The rotating grinding wheel 6 is driven by a separate motor 21. However, there is also the possibility of driving the grinding wheel and the worm with a common motor, with a gearbox located between the screw shaft and the hollow grinding wheel shaft.

In the vertical embodiment of FIG. 3, both the grinding wheel 6 and the worm J are driven by a common motor 7 arranged below the machine. In order to save construction space, the gearbox 10 is arranged inside the chamber U, into which the grind falls after grinding. Above the grinding box 4, an extruder roller 1 is arranged, through which the screw 3 extends upwardly into the funnel 22. To prevent bridges forming in the funnel 22, mixing elements 23 are mounted at the top of the screw. by passing the gap between the screw and the extruder cylinder into a conical annular gap between the grinding wheels.

Rapidly worn parts such as bushings in the extruder barrel, grinding discs, reciprocating threads, grilles, bearings and the like are expedient to be designed as replaceable.

It is expedient to provide the extruder cylinder, grinding discs and possibly other parts to be heated during the manufacturing process with a cooling device.

Claims (10)

PATENT CLAIMS 1. A grinding device consisting of a screw extruder and a grinding device fed by it with two grinding wheels, forming a conical grinding gap therebetween, one of which has a central inlet for the material to be ground and at least one of which is rotary driven, characterized by characterized in that the extruder screw (3) and the grinding discs (5,6) are arranged concentrically and that the annular gap between the extruder screw (3) and the extruder roller (1) directly proceeds through the annular gap between the grinding discs (5,6). Device according to claim 1, characterized in that the end part (8) of the screw of the extruder (3) projects into or passes through the grinding wheels (5,6). Apparatus according to claim 1, characterized in that the rotating grinding wheel (6) is preferably driven separately, in the same direction or in the opposite direction and at a higher speed than the screw of the extruder (3). Device according to claim 1, characterized in that means (12) for axially displacing one grinding wheel (5) relative to the other (6) are provided. Device according to Claims 1 and 2, characterized in that the screw of the extruder (3) is provided with a thread for the reciprocating movement of the material in the area located in the grinding wheels (5, 6). 6. The apparatus of item 1, wherein: i 5 Preferably, the tapered gap between the grinding discs š (5,6) narrows at least in the entry area. Apparatus according to claim 1, characterized in that at least one of the grinding wheels (5, 6) is equipped with ribs (13) in the region of the grinding wheels. by serving Apparatus according to claim 1, characterized in that the common geometric axis of the screw (3) (5, 6) is arranged horizontally and radially in the feed hopper (2). This is done by the grinding discs that is predicted C * J 1 · ^ 7 Apparatus according to claim 1, characterized in that the common geometric axis of the screw (3) (5,6) is arranged vertically and that the hopper (21) is arranged. This is done, and the grinding discs are assumed at an angle Device according to claim 1, characterized in that the common geometric axis of the screw (3) and the grinding wheels (5,6) is arranged vertically, that the screw (3) extends axially through the grinding wheels (5,6) and that its end extends into the vertically extending feed hopper (22). r-'i Apparatus according to claim 10, characterized in that the screw (3) is provided with mixing elementary elements (23) in the space of the funnel (22). Device according to claim 1, characterized by arranging the grating (24) before passing the extrusion path from the screw (3) between the grinding wheels, with narrow blades in a direction perpendicular to the extrusion direction but with blades deep in the extrusion direction. • .i i J 'í '.Ί í i i 13. Apparatus according to claim 10, characterized in that the upper part of the funnel (22) is rotatably driven and is internally provided with circumferential threads or ribs for forced filling into the extruder screw.