Electrically operated fluid flow valve arrangements

An electrically operated fluid flow valve arrangement, the arrangement including:

• an electrically powered magnetic field generator;
• a valve body defining a valve chamber, an inlet port and an outlet port;
• a valve member located in the valve chamber and movable between a closed condition in which the valve member locates against one of the ports to prevent fluid flow through said one of the ports and an open condition in which the valve member permits fluid flow through said one of the ports;
• and
• a ferromagnetic member having a first switchable pole;
• and the arrangement being such that:
• the valve member includes a permanent magnet;
• the first switchable pole is formed of a ferromagnetic material;
• the ferromagnetic member defines a passage which communicates with the valve chamber via said one of the ports;
• in use, in a first latched condition, the valve member is retained by magnetic attraction to the first switchable pole in one of the closed or open conditions;
• in use, in a second latched condition, the valve member is retained by magnetic attraction to the first switchable pole in the other of the closed or open conditions;
• in the first and second latched conditions, the generator is in an unpowered condition;
• and
• the valve member is movable from one latched condition to the other by operation of the generator.