Method for drilling holes in a substrate, in particular an electrical circuit substrate, by means of a laser beam

摘要

Disclosed is a valve having a housing with a valve seat for a two-piece flap which is rotatably mounted on a drive shaft. An annular piston seal and an adjacent cover disk are disposed between the first part and the second part of the two-piece flap so as to revolve therearound. The diameter of the cover disk is smaller than the diameter of the annular piston seal which is embodied as a metal ring that is provided with a gap. The invention also relates to the use of the valve as a gas recirculation valve.