Device for measuring residual pressure in vacuum interrupter during production or verification of tank, has permanent magnet comprising elementary permanent magnets forming cylindrical structure to create uniform magnetic field along axis

摘要

The device has an axial magnetic field generating member (22) including a ring-shaped permanent magnet (24) to create uniform magnetic field along an axis (Z). A circuit (14) applies high voltage between electrodes (6, 8). The field cooperates with the voltage to generate magnetron discharge in the tank. A circuit measures an electric current from the discharge and determines residual pressure from the current. The magnet has parallelepiped-shaped elementary permanent magnets forming a cylindrical structure i.e. stack of elementary rings, to create a uniform magnetic field along the axis.