Method and apparatus for indirect and external adjustment of the setting pressure of a shunt valve

摘要

Indirect external adjustment is described for the popping pressure of a shunt (314) valve of the type having one or more members (322-380) adapted to move under the influence of a magnetic field. An adjustment device (390) is positioned in proximity to the valve. The adjustment device includes a plurality of electromagnets (392-395) which are selectively energized through a sequence of steps in which different ones of the electromagnets are energized at successive steps. The sequence of energization and the orientation and strength of the electromagnets is such that the member(s) is (are) caused to move in response to the sequence of energization and to thereby adjust said popping pressure.