Liquid selective automatic bilge pump control

摘要

A highly reliable bilge pump control system which distinguishes between oil and water and operates without a mechanical float switch. It uses a conductivity type probe of special construction which is unaffected by sludge and contamination at the oil-water interface. Multiple probes at varying depths feed high impedance operational amplifiers which operate a conventional pump through digital circuitry which assures that no oil is pumped from the bilge.