button assembly 327 can be moved either away from or towards orifice plate 329 thereby controlling the flow of fluid through orifice plate 329 for example if the magnetic flux creates a pole on the end of bypass assembly 317 that is opposite in polarity to magnet 626 the attractive force between bypass assembly 317 and plunger button assembly 327 via magnet 626 will pull plunger button assembly 327 away from orifice plate 329 which allows fluid to flow if the magnetic flux creates a pole that is the same in polarity as magnet 626 bypass assembly 317 will force plunger button assembly 327 into orifice plate 329 which will shut off the fluid flow thus depending on the magnitude and direction of the flux and the strength of magnet 626 a desired fluid flow can be obtained in the above described embodiments opening 610 in orifice plate 329 is a central through hole however in other embodiments opening 610 can be an annular ring of slots 700 shown in fig7 a or holes 710 shown in fig7 b or a combination of both in these embodiments the annular ring of holes or slots extend through protruded portions 720 of orifice plate 329 shown in fig7 c plunger button assembly 327 has a central hole 730 or slots not shown and sealing surface 740 which abuts against protruded portions 720 of orifice plate 329 without any magnetic flux protruded portions 720 are sealed against sealing surface 740 thereby preventing fluid from flowing through the holes or slots in orifice plate.