GB633253A - Apparatus for the closing and opening of electrical circuits by variation of liquid level in tanks, wells, boreholes, reservoirs, sewage chambers and the like - Google Patents

Abstract

633,253. Mercury and other conducting-liquid switches; actuation of switches. STUBBS, A. D. Feb. 9, 1948, No. 3658. [Class 38 (v)] A mercury switch immersed in a tank, well, borehole, &c., so as to control pumps or give signals at certain liquid levels, comprises a compressible mercury container p connected to the lower end of an air chamber j into which are sealed electrodes k, l, m. The chamber and container p are protected by a cylinder a having holes b permitting the liquid to act on the container p. Rises in the level of the liquid compress container p and force the mercury upwards into chamber j to engage the electrodes which are sealed by sleeves d, e, g, which fit over a double-cone rubber sleeve f. The part of the cylinder a around the chamber j may be omitted if the latter is made of steel (Fig. 2, not shown). In a further modification (Fig. 3, not shown), for use where the rise in level is only a few inches, the upper end of the chamber j is enclosed in a rubber sleeve secured thereto at the top and bottom, access being had to the interior of the sleeve through openings in the chamber.