Abstract: The invention relates to an apparatus for punching plastics, in particular for producing plug-in punchings for smart cards, whereby the stamping punch cooperates with a die-plate and the plastic to be punched is disposed between the stamping punch and the die-plate. In order to avoid disadvantages with respect to the quality of the punched edges, the cutting edge of the stamping punch is formed according to the invention so as to have a punching angle smaller than 90°.

Abstract: Liquid-conveying pipelines are tested for leaks during inoperative periods. To this end, the pipeline is hermetically closed at its two ends and the pressure prevailing in the interior of the pipeline is continuously measured. Once the pressure prevailing therein is found to drop, a substitute liquid is conveyed through the pipeline in the quantity necessary to make up for that decrease in volume of the normally conveyed liquid which is caused by the relevant temperature drop, an alarm device is actuated if the pressure continues to drop, and the magnitude of the leak is ascertained as an inference from the quantity of substitute liquid introduced per unit time into the closed pipeline.