Double electromagnet device for translatory valve movement - causes larger electromagnet to drive core of smaller one for valve opening, and then to be retracted allowing rapid reclosure of valve

摘要

Two electromagnets (18,20) are arranged with extensions (24,28) of their respective cores (22,26) aligned with each other to operate the valve (14) against the resistance of a spring (15). The larger magnet (18) opens the valve, and the smaller one (20) holds it in the open position when the larger is de-energised. At that juncture there is no contact between the cores so that, when the smaller electromagnet is de-energised, the spring recloses the valve quickly. USE/ADVANTAGE - In casting of molten metals under vacuum, valve can open effectively against spring force but can still be closed very rapidly.