Control valve assembly including valve position sensor

An apparatus for determining the position of an electromechanical valve assembly comprising valve means movable between open and closed positions, electromechanical means having a pair of electrical leads for actuating said valve means between said open and closed positions in response to a first electrical signal having a relatively low frequency applied to said leads, sensing means for disclosing the position of said valve means in response to a second electrical signal having a relatively high frequency applied to said leads, means for generating said first electrical signal electrically connected to said leads, means for generating said second electrical signal electrically connected to said leads, and means for electrically isolating said means for generating said first electrical signal from said means for generating said second electrical signal.

A limited angle torque motor for rotating a shaft through a limited are incorporating a shaft position indicator comprising a shaft having an axis along its length, shaft bearings in which said shaft is journaled for rotation about said axis, a permanent magnet mounted on said shaft having magnetic poles transverse to said axis, a stator circumferentially disposed about said axis including a stator coil for conducting a first electric signal of a relatively low frequency to generate an electromagnetic field for interacting with the magnetic field of said permanent magnet to apply a torque to said shaft on said axis, said stator coil including electrical leads for supplying electrical current to said stator coil, and sensing means for disclosing the rotational position of said shaft in response to a second electrical signal applied to said leads and having a relatively high frequency.