Abstract: A magnetic control device comprising one pair of permanent magnets cooperating with armatures to form first and second air gaps and, means for inverting the direction of magnetization of one magnet. In a first direction of magnetization, the flux closes through the first air gap, while, in the opposite direction, the flux is at least partially cancelled in the first air gap and passes through the second air gap, which is substantially smaller than the first air gap. Such a device is adapted to actuate a two way valve.

Abstract: A magnetic device comprising two permanent magnets, armature members forming with said magnets a closed magnetic circuit and an external air gap, and means for reversing the direction of magnetization of one of the magnets, whereby the flux is prevented to close along the magnetic circuit and caused to close through the air gap, or caused to close along the magnetic circuit, the flux in the air gap then being suppressed. The said means consist of two distinct coils wound about the magnets. One of the coils is energized for establishing the flux in the air gap, while the other coil is energized for suppressing the flux in the air gap.