Illinois Tool Works Inc.

Jeffrey P Rudd

James M Pellegrini

Thomas A Mignone

David Malcom Howie

Brian J Bonenfant

Levi G Fox

James Pelligrini

David M Howie

A liquid level sensor employs a set of axially displaced magnetic sensing switches and a magnet on a float that may rise and fall on liquid level to activate and deactivate the switches. The switches and magnet are configured so that movement of the magnetic float activates a new switch before deactivation of an adjacent previously activated switch. An electronic circuit provides a signal based on the uppermost activated switch to provide a signal that is monotonic with liquid level. The design may be readily implemented using reed switches and a resistive ladder.

Multi-level liquid level magnetic sensor

A capacitive touch switch suitable for use in areas with high environmental and electrical contamination employs a complex excitation signal that is demodulated to better distinguish it from environmental effects. Improved discrimination allows these sensed signals to be offset against a signal developed by a reference electrode to allow the system to operate robustly with contamination on the electrodes that would otherwise trigger or obscure pulses.

Pulsed antenna capacitive touch switch

An inductive liquid-level sensor employs a central shaft supporting multiple independent electrical loops that may be interrogated to detect the proximity of the conductive element in the float rising and falling with changes in liquid height outside of the shaft.

Inductive liquid-level sensor

Growing community of inventors

Foxboro, MA, United States of America

Jeffrey P Rudd