Schwimmergesteuerte elektrische Schalteinrichtung

1,008,388. Machines with permanent magnets; magnetic switches. ROBERTSHAW CONTROLS CO. April 10, 1962 [April 12, 1961], No. 13834/62. Headings H2A and H2B. [Also in Divisions Gl and G3] The level of a liquid in a container T is controlled by a control device 5 comprising a non- magnetic tube 22 having a magnet 32 mounted on its exterior and coaxial therewith and a magnetic shunt 110 which moves along the longitudinal axis of the tube and inside the tube under the control of the level of the liquid, the arrangement being such that the shunt diverts sufficient of the magnet's flux from its associated armature 62 to cause movement of the latter and operation of a switch. As shown in Figs. 1, 2 a float 18 is connected via a piston rod 114 to piston 112 of ferrous material such that as the level of the liquid in the container rises and falls the piston moves upwards and downwards in the tube 22 so affecting the flux in the airgap 41 between the magnet 32 and its associated armature 62, with the result that the armature is held or released dependent upon the position of the piston. The armature 62 of the relay 30 is secured to an actuator plate 64 pivoted with a flange 42 of pole shoe 38 by means of a hinge pin 58 carried in a groove 66 extending across the face of the actuator plate 64 and clamped in position by the end of the overlapping end of the armature 62. The armature is biased in a clockwise direction by a pair of springs 102 mounted on a clamp 78 and its pivotal movement is limited by a pair of screws 74, 76. When the armature is caused to move towards the magnet 32 a pair of screws 72, passing through the actuator plate, render switching means 98 operative. The latter are connected to element 6 which controls the flow of liquid into the container T. In the embodiments of Figs. 6, 7 (not shown) switching means are dispensed with and a pneumatic switching device is used.