Equalising potentials of tanks without sparking - using variable resistance in series with conductor joining tanks, resistance being reduced from very high to zero

摘要

To bring the potential of one body (1a), like an aircraft fuel tank, to that of another (1b), like the tank of a refuelling vehicle, without the occurrence of sparks, a conductor (3) in series with a variable resistance (5) is used. The resistance is in series with the conductor and the second body. The resistance is set extremely high before the conductor is attached to the first body, and then is gradually reduced to zero. For an aircraft refuelling set-up, a detector circuit can recognise when the potentials on either side of the resistor are equal and then send a signal to open a valve in the refuelling pipe to allow safe refuelling. USE/ADVANTAGE - Simple device giving safe aircraft refuelling without hazard of explosion.