DE973018C - Device for heating strangfoermiger objects made of plastic-elastic materials, such as rubber u. Like., in the high-frequency electric field - Google Patents

Description

Device for heating strand-like objects made of plastic-elastic Masses such as rubber and the like in the high-frequency electric field In the preparation of of tubes or strands in the extrusion process must often for reasons of Further processing possibility the pressed material is supplied with an additional amount of heat to put it in a certain plastic-elastic state. These As is known, additional heat can be supplied by warm air, steam baths or water baths take place. At the high pressing speeds, as in the case of the above-mentioned objects are used, such devices require a large amount of space can extend up to several hundred meters.

It is now known that it is heated by a high-frequency electric field to undertake. In this case, when using an elongated electrode, through which the material to be heated must run through, difficulties for uniform heating arise because the extension of an electrode does not exceed one eighth of that used Should be wavelength. Otherwise standing waves appear on the electrode which lead to higher heating at the points of higher voltage.

One has already been constructed in the manner of a screw conveyor Device for heating known in the high frequency electric field. The core of the rotatably arranged screw located on the inside has one as the inner electrode serving coating on; the outer electrode, however, is formed by that of the worm surrounding coat.

With the help of this device, a relatively large length extension can only granular, misshapen goods, but not strand-shaped, against mechanical Stresses on sensitive objects, e.g. B. those made of unvulcanized rubber, moved and heated in the process.

Furthermore, there is a device for vulcanizing the insulation electrical lines or cables in a high-voltage electrical field with concentric mutually arranged electrodes, of which the inner one is rotatably mounted, are known. With their help you can close the rubber covering of wires or cables Vulcanize space. In this way, however, it is not possible to achieve plastic-elastic To vulcanize masses of great length, such as rubber blanks, as the Dimensional stability of the latter due to the lack of a core with high tensile strength (e.g. B. rubber-coated metal wires) is so small that even small relative movements would cause tearing.

It has now been found that one can also use very long, strand-shaped, plastic-elastic Masses in spite of their low tensile strength with the help of concentric to each other arranged cylindrical electrodes in the high-frequency field: vulcanize in a very small space can. The device according to the invention which is used for this purpose is characterized in that that the roll shell, rotatable about a vertical axis, of the inner one, as a bobbin formed electrode with upright helical bands preferably is made of plastics to guide the strand-like objects and that at the same time as the rotary movement of the roll shell is also moved in the axial direction is that the run-up point for the rope-like material does not change locally. According to FIG. 1, two conditions must be met: First, the inner one, in order to its vertical axis rotatable, serving as an electrode roll shell I with upright standing helical belts 4, which are used to guide the strand-shaped Items 3 serve.

Second, the roll shell should also move axially during rotation Move direction. The speed of this linear movement is to be regulated in such a way that that the run-up point for the strangular good does not change locally.

Concentrically around the roller is at a distance as a counter electrode a metallic cylinder 2, which is set up insulated and connected to a high voltage source connected. The one located in the high-frequency field, wound on the roller The material to be treated is heated in the high-frequency field and can then be removed from the roller again subtracted from. In order to give off heat to the roller during vulcanization can avoid the latter with steam, hot water, electrical energy, etc. in addition be heated. But you can also with a jacket made of plastic, laminated plastic and the like.

The high-frequency field also occurs in these coatings heating, so that there is no need for additional heating of the roller can.

Claims (1)

PATENT CLAIM: Device for heating string-shaped objects large length extension made of plastic-elastic materials such as rubber and the like, in the high-frequency electric field with concentric cylindrical Electrodes, the inner one of which is rotatably mounted, characterized in that the roll shell of the inner, rotatable about a vertical axis, as a winding body formed electrode (I) with upright helical strips (4), preferably made of plastics, is provided to guide the strand-like objects and that at the same time as the rotary movement of the roll shell is also moved in the axial direction is that the run-up point for the rope-like material does not change locally. Documents considered: German Patent No. 735 3 (15; French patents No. 968 440, 939 o78; excerpt from "Official Gazette" dated Mar. 28 mg50, pp. 1238 and I239 to U.S. Patent Application No. 650,048.