Switch system for indicating changes in liquid level

Abstract From the Canadian patent

This invention relates to an improved method and apparatus for detecting the level of a first fluid. It includes a reservoir within the first fluid the, reservoir being bounded by a flexible membrane at its lower portion for containing a second fluid. The reservoir contains at least one switching means biased to assume a first position when the second fluid is below a predetermined level and adapted to assume a second position upon the rising of the first fluid into pressure exerting contact with the flexible membrane. The rising first fluid compresses the lower flexible membrane portion of the reservoir and causes the second fluid within the reservoir to also rise thereby causing the …