Valve actuator

In combination with a valve body having an intermediate passage that has a valve seat therein, said valve body having a fluid inlet and fluid outlet that are at all times in communication with said intermediate passage and said valve seat respectively, a device operable from a source of electric power for controlling the flow of fluid through said valve body, which device includes:

• a. a housing assembly that includes a cylindrical shell formed of a material having substantial magnetic permeability, said shell having a first open end and a second closed end that has an opening formed therein, a tubular guide having first and second ends, which guide is longitudinally aligned relative to said shell and extends through said opening, and first means for securing said housing assembly to said valve body with said guide being axially aligned with said valve seat;
• b. an elongate armature having first and second ends, with said armature being slidably mounted in said guide, and said armature being formed from a ferro-magnetic material having substantial permeability and low retentivity;
• c. a resilient valve member on said second end of said armature that sealingly engages said valve seat when in a first position and in pressure contact therewith;
• d. second means that at all times exert a first force on said armature in a direction that tends to move said armature to said first position;
• e. a solenoid in said housing that extends around at least a portion of said guide, with said solenoid being capable of energization from said source of electric power;
• f. permanent magnet means of fixed polarity in said housing, said permanent magnet means adjacent said first end of said shell, said fixed polarity being such that the direction of the major portion of the magnetic flux from said permanent magnet means is through said shell and armature to tend to hold said armature in a second position where said valve member is spaced from said valve seat and fluid may flow from said inlet to said outlet, with said magnetic flux being of sufficient strength to overcome said first force exerted by said second means when said armature is in said second position but now when said armature is in said first position;
• said permanent magnet means including:
• 1. a permanent transversely magnetized ring having first and second side surfaces;
• 2. first and second plates of a material having substantial magnetic permeability that are in abutting contact with said first and second side surfaces of said ring, said first plate in abutting contact with the interior of said shell, said second plate defining an air gap with the interior surface of said shell;
• and
• 3. a core of material having substantial magnetic permeability that projects from said second plate into the interior of said solenoid;
• g. third means for momentarily nullifying the flow of said magnetic flux through said shell and armature to permit said second means to move said armature to said first position;
• and
• h. fourth means for electrically energizing said solenoid when said third means is not operating that said magnetic flux from said permanent magnet means and the magnetic flux from said solenoid concurrently flow through said armature in the same direction and exert a second force on said armature that is greater than said first force to move said armature from said first to said second position.