Fluid barrier circuit for high pressure machine seals - is held at pressure dependent on control reservoir level above machine pressure

摘要

A circuit provides a ratio of 1 : 3 between the min. and max. values of the operating voltage (Ue), the energy requirement of the energising coil (S1) for the switch remaining constant over the full operating range. A partial surface is eliminated from the positive half wave (A, B, C) of the control voltage for the coil (S1) dependent on the magnitude of the operating voltage, using a constant time circuit (R3, C1) and a FET (T1). ADVANTAGE - Ensures same energy requirement for coil for each operating voltage.