Electromagnetic apparatus and method for controlling fluid flow

An electromagnetic actuator, comprising:

• a solenoid coil and an armature housing constructed and arranged to form an armature chamber;
• a ferromagnetic armature including a proximal part and a distal part linearly movable inside said armature chamber;
• said ferromagnetic armature including a shoulder constructed to provide a magnetic flux path;
• a radial magnet disposed in a fixed arrangement with respect to said armature housing, said radial magnet having its poles oriented perpendicularly to a direction of said linearly movable ferromagnetic armature;
• a control circuit constructed to apply a coil drive current to said solenoid coil and thereby cause a linear displacement of said distal part of said ferromagnetic armature with respect to a valve passage controlled by said actuator;
• a pole piece disposed in a fixed arrangement with respect to said armature housing and located near said proximal part of said linearly movable ferromagnetic armature;
• and
• said radial magnet located with respect to said shoulder and said armature housing being constructed to provide two magnetic flux paths extending from said proximal part to said distal part, and said armature, said shoulder, said armature housing and said pole piece being constructed and assembled to provide a magnetic flux path between the poles of said radial magnet to maintain said armature in a stationary position, when in said retracted state or said extended state, by a force of a magnetic field without application of said coil drive current.

An electromagnetic actuator, comprising:

• a solenoid coil and an armature housing constructed and arranged to form an armature chamber;
• a ferromagnetic armature including a proximal part and a distal part linearly movable inside said armature chamber;
• said ferromagnetic armature including a shoulder constructed to provide a magnetic flux path;
• a radial magnet disposed in a fixed arrangement with respect to said armature housing;
• a control circuit constructed to apply a coil drive current to said solenoid coil and thereby cause a linear displacement of said distal part of said ferromagnetic armature with respect to a valve passage controlled by said actuator;
• a pole piece disposed in a fixed arrangement with respect to said armature housing and located near said proximal part of said ferromagnetic armature;
• said radial magnet located with respect to said shoulder and said armature housing being constructed to provide two magnetic flux paths extending from said distal part to said proximal part and said pole piece, and said armature, said shoulder, said armature housing and said pole piece being constructed and assembled to provide a magnetic flux path between the poles of said radial magnet to maintain said armature in a stationary position, when in said retracted state or said extended state, by a force of a magnetic field without application of said coil drive current;
• and
• a cavity disposed inside said ferromagnetic armature constructed to receive a bias spring positioned and arranged to bias said armature toward its extended state.