Abstract: The static converter of the invention comprises a central processor (15) measuring the output voltage (TM3), the output current (TM4), the rectifier current (S) and the reverse bias time (8) of the thyristors of the switch (5). From this information it drives, through interfaces (17, 18, 20) the starting thyristors (6) comprising a series resonating circuit intitiating the oscillations of the parallel resonant load circuit (2,3).

Abstract: A device for taking samples of dust in a pipe or a chimney discharging gases, into the atmosphere.The device permits completely emptying the sampling tube of the dusts to be measured by means for rapidly and briefly closing the orifice of the sampling tube, which produces, once or several times during each sampling period, a pneumatic shock in the sampling tube which is subjected to pumping.Such a device permits effecting particularly precise measurements of the concentration of dust by weight. It also permits a continuous utilization of the device during very long periods of time without its clogging up.