flamvakt at oil and gasbrennare

摘要

This invention relates to a flame monitor which has a sensing circuit 11 with a flame sensor 10 and a sensing relay 13 which switches a sensing switch 5 which is connected in parallel with a bridging switch 4 connected to a supply line 1. With one contact, sensing switch 5 controls a fuel valve 7 and with the other contact a circuit 16 with two alternatively energized relays, a bridging relay 24 and a relay 27 for switching the flame loss simulation and a timing device 30. The bridging switch 4 switches the fuel valve 7 and a safety circuit 3 with a safety relay 22 for switching a safety switch 2 located in the supply line and a parallel connected second timing device 31. During operation the first timing device 30 is discharged, causing the bridging switch 4 to provide parallel energization of the fuel valve 7 and then the flame loss simulation is actuated by relay 27 so that sensing switch 5 switches power to circuit 16 and timing device 30 is charged. Relay 13 then removes the flame loss simulation from the flame sensing circuit 11, so that sensing switch 5 again energizes fuel valve 7, while bridging switch 4 switches safety circuit 3. The cycle then starts again. IMAGE