Adaptive magnetic field cancellation

A flow control valve comprising:

• a pipe for receiving and directing media therethrough, said pipe having an inlet for receiving said media and an outlet for dispensing said media, said media capable of retaining magnetism and conducting a magnetic field;
• a permanent magnet conducting a magnetic field through a pair of pole pieces, said pole pieces extending through said pipe between said inlet and said outlet and said pole pieces being spaced from each other within said pipe, said pole pieces conducting said magnetic field from said permanent magnet into said pipe, a space being located between said pole pieces within said pipe defining a working gap;
• a coil surrounding a portion of each said pole piece and said coils capable of receiving a current for generating an opposite magnetic field to said magnetic field from said permanent magnet, said current being adjustable from zero to a baseline neutral field current wherein said magnetic field from said permanent magnet is substantially negated by said opposite magnetic field from said coils, said baseline neutral field current corresponding to a maximum flow rate of said media when said media is not magnetized and said baseline neutral field current corresponding to substantially no magnetic field in said working gap when said media is not magnetized;
• a magnetic sensor for measuring magnetic flux within said working gap;
• a controller connected to said sensor and said controller capable of adjusting said current in said coils to a second neutral field current by detecting magnetism in said working gap from magnetized media by said magnetic sensor, said second neutral field current corresponding to substantially no magnetic field in said working gap in the presence of said magnetized media and said second neutral field current corresponding to a current necessary to provide a maximum flow rate in the presence of said magnetized media.