GB863742A - Improvements in or relating to electric pressure-switches - Google Patents

Abstract

863,742. Fluid actuation of switches. FAIRHURST, J. Aug. 13, 1959 [Aug. 27, 1958], No. 27432/58. Class 38 (5). A pressure-switch suitable for controlling the level of granular or liquid material comprises a cylindrical metal body 10 whose upper edge 22 is sealed to a flexible metal diaphragm 24 having an insulating reinforcing disc 28 and an insulating stem 31, depression of the diaphragm 24 being limited by vertical screws in two parallel cross-bars 29, Fig. 2 (not shown). The stem 31 can engage the actuator button 21 of a microswitch 20, mounted between a pair of levers 14 pivoted at 15 to a lug 13 and urged by a spring 19 against an adjustable abutment screw 17, the micro-switch 20 being connected to a mains socket 39, and to a lamp 42 to facilitate setting. The periphery of the diaphragm 24 may be sealed to the body 10 by an adhesive resin, by a rubber washer and sealing-ring, or by a fusible alloy, Figs. 3 . . . 6 (not shown). The diaphragm may be arranged to engage the button 21 directly, and its outer surface may be protected by a layer of sponge and of rigid material or by a layer of plastics material with or without sponge. The body 10 may be mounted in a fluid-container wall with the diaphragm 24 in, or at a slight angle to, the vertical plane. The switch may be arranged to operate by internal pressure on the diaphragm 24 by connecting a closed deformable tube to the body 10. The micro-switch may be connected to a plug-in relay on the base-plate 12.