GB1233799A - - Google Patents

Abstract

1,233,799. Liquid level indication. W. BOURS [trading as J G. MERCKENS K.G.], Oct. 30, 1968 [Oct.31, 1967], No.51534/68. Heading G1H. Also in Division H1] A float operated movable magnet switch has an armature on an extension of the movable magnet member and a testing magnet which can be used to act on the armature to cause the movable member to actuate the switch. As shown, the float 4 is mounted on a rod 5 which has a magnet 10 at its upper end to act upon magnetic contact units 12- outside a non-magnetic tube 7 into which the rod 5 extends. A stop 19 on the rod 5 engages a guide disc 11 on the bottom of the tube 7 to limit downward movement of the float 4 and magnet 10. Above the magnet 10 the rod 5 has an extension 9 which carries an armature 15 within an extension 8 of the tube shown. The armature 15 may be of soft iron or a permanent magnet and is movable by an external testing magnet 16 to test the switch operation. As shown an axially magnetized annular permanent magnet 16 is the testing permanent magnet and is mounted on the bell-shaped end of a cap 18, which may be made from plastics material, of such dimensions that the magnet 16 can be moved beyond the armature 15 when the stop 19 is in engagement with the disc 11, to a position in which it no longer influences the armature 15. In an alternative arrangement Fig. 2 (not shown) the testing magnet is an electromagnet secured to the outside of the tube extension 8 and energizable in either direction to influence a permanent magnet armature on the float rod extension. A movable electromagnet may also be used.