Abstract: The invention contemplates a float-operated electrical switching system with two fluid-level indications and with provision for mechanical adjustment of the difference in elevation between the two indicating points. The switches are magnetically actuated in accordance with proximity of a permanent magnet carried by the float. The float is guided on an upright magnetically transparent tube which houses the switches, and for at least one of the switches mechanical adjustment of elevation within the tube is available via external access at the upper end of the tube.

Abstract: The invention contemplates an improved magnetically operative flow switch wherein the viscosity sensitivity of a flow-responsive movable metering member is materially reduced, as compared with past constructions. The improvement results from so devising a flow-metering passage through the movable member that such flow is taken only from the center and not from the wall of the inlet-flow passage in which the metering member is movable.

Abstract: The invention contemplates an improved electric switch which changes its state via float response to achievement of a particular liquid level. The construction features mechanical seal and shield structure whereby liquid is kept out of the region of float guidance, with the result that float response is substantially isolated from sloshing action and from liquid contamination.