Displacement transducer for sensing position of magnet - has array of magnetic reed switches in circuit with indicating meter

摘要

A displacement transducer is used to determine the position of a sensor incorporating a permanent magnet. It may be used to determine liquid level or the position of a 'pig' in a pipe. The transducer comprises an insulating material strip (14), magnetic reed switches (4), resistors and a ring permanent magnet (3). The reed switches (4) and the resistors make up a circuit with a metter (7). The permanent magnet (3) may be fitted to a float (2) to determine the level of a liquid (11). The magnet (3) is radially magnetised and produces a flux which is constant about the centre of the magnet. The magnet may turn about its axis without effect of the reed switches. The meter (7) gives an indication of the position of the magnet (3) along the tube (1).