| 摘要 |
1,217,725. Magnetic switches. PARMATIC Inc. 8 Jan., 1968 [11 Jan., 1967], No. 1141/68. Heading H1N. [Also in Division G1] A magnetic device which may act as an indicator or switch actuator has a permanent magnet 7 which retains a plunger 3 against the bias of a spring 11 and permits the plunger to be moved by the spring when flux is diverted by magnetizable means which approaches the magnet. The magnetizable means may be particles in a fluid flowing past the magnet (Fig. 1, not shown) or a piston 9 biased by a spring 10 and responsive to pressure on one or both sides thereof. Pressure inlets 21, 25 may be constricted to limit the effect of pressure surges and respective filters 17, 28 may be provided. The plunger 3 may act as an indicator or act upon a lever (not shown) which operates a microswitch (not shown). When the device is used to indicate differential pressure in a fluid which has a high viscosity when cold, a bimetal 5 may retain the plunger 3 until a predetermined temperature is reached. |
