Patent ID: 8540208

Claim:
A bistable valve ( 100 ), comprising: an armature ( 108 ) movable to selectively block and unblock at least a first port ( 104 ); a biasing device ( 112 ) configured to provide a first biasing force to the armature ( 108 ), with the biasing device ( 112 ) biasing the armature ( 108 ) toward a first position blocking the first port ( 104 ); a plurality of permanent magnets ( 114 ) substantially annularly arranged around a central axis of the bistable valve ( 100 ) and configured to provide a second biasing force to the armature ( 108 ) substantially opposite to the first biasing force, with a magnet of the plurality of permanent magnets ( 114 ) including poles that are substantially parallel in orientation with the central axis and wherein magnetic flux of the magnet changes in strength in a radial direction with respect to the central axis; and an electromagnetic coil ( 116 ) configured to generate a third biasing force when energized with a first current polarity, with the third biasing force being substantially opposite to the first biasing force, wherein the third biasing force in combination with the second biasing force overcomes the first biasing force and moves the armature ( 108 ) to unblock the first port ( 104 ).