Schaltungsanordnung zum Steuern eines ersten und eines zweiten Vorganges in Abhängigkeit eines Steuersignales

摘要

Apparatus for monitoring and controlling the flow of a combustible gas includes a solenoid operated gas valve to control the gas flow. The solenoid is energized from an AC supply via a thyristor switch. When the gas is ignited an ionization current flows through the flame and is monitored to control the trigger electrode of the thyristor. When the flame is out the thyristor is not triggered so that it remains cut-off and deenergizes the solenoid. This closes the gas valve to cut off the gas flow. Triggering may take place through a phase advance circuit. Ignition sparks may be provided by means of a capacitor and a step-up transformer arrangement in which the capacitor is periodically discharged through the thyristor to produce spark pulses via the transformer.