DE2156198C3 - Process for processing used thermoplastics and use of a device for carrying out the process - Google Patents

Description

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The main patent relates to a process for processing used thermoplastics, in which the soiled plastic is washed, dried, crushed and then granulated is, and solves the task of ver simplifying the washing stage so that the processing of used plastics and their reuse for extrusion, injection molding, or other purposes, cost benefits compared to the use of new goods. For this purpose it was suggested that the washing of the Plastic under the action of the crushing work and the washed plastic before freed from the majority of the detergent liquid after drying by centrifugation.

The additional patent is based on the knowledge and the task that the general inventive concept according to the main patent lies in the washing process that takes place during the comminution and is protected for itself. The invention relates to thereafter _c i _n process according to the preamble of claim 1. On this basis, the measure according to the characterizing part of. Claim 1 is proposed. The process allows the contaminated plastics to be thoroughly freed of foreign matter "because they are agitated vigorously during the comminution process and the washing liquid, if necessary with the addition of detergents, can easily get to the foreign matter Plastic strongly adhering foreign matter such as imprints, so that the problem of coloring the regenerated plastic is at least alleviated by imprints for the regeneration of the plastics Washing process is usable.

The additional patent is also based on the task of making the process according to the main patent more effective to design. Based on the preamble according to claim 2, the solution to this problem is the characterizing part of claim 2 er.inchmbar.

That means washing. Crushing. Drying and granulating the plastic in one and the same Device is made so that the effort for a separate centrifuge and a separate Granulating device (e.g. according to German Auslegeschrift 1 679 834) is omitted; this measure is particularly advantageous because it considerably reduces the outlay on equipment and procedures. Included it must be assumed that the removal of the liquid is largely due to the centrifugal force which affects the washing liquid of the plastic circulating with the impact shredding tool, but also due to the evaporation of the liquid due to the rotating impact crushing mechanism / eug generated heating of the plastic takes place.

The measure that the plastic using the heat generated during the comminution is granulated is already known per se from French patent specification 1 535 932, without there being a Washing process is mentioned. From the same patent it is known that granulating with additive a cooling medium takes place, a measure that is also in connection with claim 2 of the present Additional patent is applicable.

Claim 3 indicates. which device when performing the method according to claim 2 in can be used appropriately.

An embodiment of the device according to claim 3, but by means of which also the method according to claim 1 can be carried out is shown in the drawing. Here shows

F i g. 1 shows a longitudinal section of a device according to the invention and

F i g. 2 is a plan view.

A vertically standing round container 1 has stationary in the lower area on the side wall and on the bottom Knife 2, which is also designed as a knife and attached to a rotating carrier 3 Crushing organs 4 are moved past. The carrier 3 sits on the shaft of one at the bottom of the container attached electric motor 5.

A supply line 6 for the washing liquid is on provided upper, upwardly open container part. The drainage of the washing liquid and foreign matter

takes place through the outlet nozzle 8 equipped with a sieve plate 7 The outlet connection 9, which can be closed by an actuating device 11, serves to protrude the granulated Plastic.

The soiled plastic parts to be processed are thrown into the container from above without being crushed, with the rotating crushing organs 4. At the same time, washing liquid is applied via the supply line 6. It penetrates them already more or less shredded plastic parts and dissolves, if necessary with the help of a special detergent, the dirt parts. This and the washing liquid are discharged via the outlet nozzle 8, wherein the sieve plate 7 prevents already crushed plastic parts from being discharged.

The duration of the washing process depends on the Degree of pollution. As soon as the draining washing liquid emerges clearly, its further supply is interrupted, while the comminuting organs 4 continue to rotate. The one adhering to the plastic parts Liquid is largely removed by the centrifugal effect of the co-rotating and plastic parts forming a surface mirror corresponding to line 12 and finally to achieve a high degree of dryness through evaporation due to the heated by the crushing elements 4 Plastic parts.

After that, the plastic parts remain exposed to the rotating shredding organs as long as until compression and agglomeration has taken place. It can be useful for this towards the end of the last one Briefly introduce a cooling liquid via injection nozzles 13 in the method step. After that it will solidified and cooled agglomerate that no longer tends to stick together via the outlet connection 9 withdrawn and can now be used again for processing on calenders, in extruders and the like will.

1 sheet of drawings

Claims (3)

Patent claims: 1. Procedure for processing used thermoplastic plastics, such as foils, hollow bodies, deep-drawn products, in which the dirty Plastic is washed, dried, crushed and then granulated, whereby the washing of the plastic is carried out under the action of the crushing work and the washed plastic before drying by centrifuging most of the detergent liquid exempted, according to patent 2 005 360, characterized in that the method limited to washing and simultaneous crushing of the plastic; vird. 2. Process for processing used thermoplastics such as foils, hollow bodies. Thermoformed products in which the soiled plastic is washed, dried, and shredded and then granulated, which involves washing the plastic under action does the shredding work and the washed plastic before drying through Centrifugation freed from most of the detergent liquid, according to patent 2 005 360. thereby characterized in that freeing the washed plastic from the detergent liquid by Centrifugation is carried out using the centrifugal component of the crushing force, and that the plastic is then in a known manner, taking advantage of the resulting from the comminution Heat is granulated. 3. Use of a washing and crushing device forming a single unit, the in a manner known per se has a standing container, at the bottom of which a container is arranged around the axis of the container rotating, almost up to the container wall reaching cutter bar is provided with the from the container wall projecting fixed knives cooperate, and their container further in the upper area a lockable feed for washing water and in the bottom area one with has a sieve provided opening, according to patent 2 005 360, for carrying out the method according to claim 2.