Bi-stable valve apparatus

A bistable, electromagnetically-actuated valve comprising:

• a moving armature, movable between two end positions;
• at least one winding for electrical energization and moving said armature;
• an annular permanent magnet for providing magnetic latching;
• means defining an enclosed space containing said armature, said defining means comprising tubular means and respective end wall means closing the ends of said tubular means;
• a first valve orifice defined in a first said end wall means;
• a bore defined in a second said end wall means;
• a tube mounted in said bore and extending at least to adjacent said space, the end of said tube at least adjacent said space defining a second valve orifice, and said tube being spaced from the internal wall of said bore;
• a first pressure fluid connection connected to said first valve orifice;
• a second pressure fluid connection connected to said second valve orifice;
• a third pressure fluid connection connected to said space around said tube and thereby to said enclosed space;
• and
• means providing communication between said third pressure fluid connection and said first valve orifice when said armature is in said second end position;
• and
• valve seats on each end of said armature, whereby when said armature is at a first said end position, said first valve orifice is closed and said second pressure fluid connection is connected to said third pressure fluid connection, and when the armature is at a second said end position, said second valve orifice is closed and said first pressure fluid connection is connected to said third pressure fluid connection.