Lawrence V Nash

US Patent:

62363247, May 22, 2001

Filed:

Mar 31, 2000

Appl. No.:

9/540279

Inventors:

Lawrence V. Nash - Wedderburn OR

International Classification:

G08B 2100

US Classification:

340619

Abstract:

A liquid level sensor intended to be placed in a tank or sump. The Sensor includes a displacer attached to one side of an elastic plate and an optical shutter blade attached to the other side. The shutter blade contains an aperture. When the displacer is not in contact with the liquid whose level is to be measured, the aperture is positioned on the optical axis of an optoelectronic slot switch, allowing radiant energy from the emitter in the switch to irradiate the sensor in the switch. When the displacer is immersed in the liquid, a moment force is created that deforms the plate, causing the aperture to move off of the switch optical axis and the shutter blade to block the radiant energy. The elastic plate constitutes part of one surface of a liquid-tight housing. The shutter and slot switch are located inside the housing.