Inventors Yuriy Pchelnikov (left) and David Nyce and one of their SEF sensors. The devices use a sensing element consisting of conducting elements periodic along the direction of propagation of the ...
LONDEX, LTD., 207 Anerley Road, London, S.E.20, have introduced a patented system (“Lectralevel”) of floatless liquid level control, designed for automatically pumping out, filling or maintaining the ...