Sealed motor driven valve

A two-position motor operated fluid control valve, comprising a valve body having at least plural passages therein, at least one slide member movable axially and operative to change said fluid flow by making a connection, in one position, between first pairs of passages and another position, between second pairs of passages, said slide member being movable axially by rotation of a drive member which is rotatable with an armature of said motor, said motor armature having a plurality of spaced apart permanent magnets embedded therein, at least one bearing assembly associated with one of said drive member and said armature, said armature being enclosed by a magnetically transparent enclosure closed at one end and hermetically sealed at its other end to said valve body and, lying closely outside said enclosure, a drive stator including drive windings and plural Hall-effect devices for commutation of said windings.

A method of operating a sealed motor which includes a stator, a plurality of drive windings for said stator, plural Hall-effect devices for commutating said drive windings, and a magnetically transparent enclosure enclosing a rotor including plural permanent magnets therein, said method including periodically energizing said drive windings with plural pulses of current, lowering an average current by periodically interrupting said pulses of said current with relatively great intervals of virtually no current at a time when net movement is desired and periodically allowing said armature to come to a virtual stop during each of said intervals, thereby rotating said armature in increments and avoiding damaging heat buildup in said sealed motor.

A motor operated valve including a valve body having at least one inlet and at least one outlet, at least one inlet flow passage and at least one outlet flow passage, at least one valve closing member positioned between said inlet and said outlet passage, at least one valve seating means within said body, said at least one valve closing member being mounted for movement between open and closed positions, said valve closing member comprising a valve cartridge, means associated with said valve cartridge for preventing rotation thereof, a bearing carried by said cartridge, an armature, a threaded drive member guided by said bearings, a threaded valve closing member engaged with said drive member and said cartridge so that rotation of said armature and said drive member cause movement of said valve closing member, said armature having a plurality of spaced apart permanent magnets embedded therein, said armature being closely surrounded by a magnetically transparent enclosure retained in a fluid-tight relation between said cartridge and a hold-down member, and exterior to said enclosure, a drive stator with drive windings therein and plural Hall-effect devices for commutation of said windings.