Magnetically-operated membrane pump - has auxiliary magnet with coil to measure main current by induction without interference with main circuit (SW 18.9.78)

摘要

The pump (3) is operated by a membrane (2) which is deflected by a cam (8) on a rocker arm (6). The rocker arm has an armature (7) on its end which is attracted by an electromagnet (9) as the magnet is periodically energised by a solenoid coil (10). An auxiliary magnet (19) carries a second coil and is fixed to the pole of the main magnet so that the same magnetic flux runs through both armatures. A current is induced in the coil of the auxiliary magnet which enables the current in the driving magnet solenoid to be measured without instruments in the driving current circuit.