Easily cleaned streaming current monitor

Abstract

A streaming current detector having a probe with an electrode holder which can be removed and replaced within only about one minute, allowing the probe to be kept on line nearly continuously even in highly contaminated wastewater. The probe also includes a reciprocating piston and a housing with both a cylindrical void and a transverse passageway. In assembled relation, the electrode holder is slidably disposed within the cylindrical void; and the piston is slidably engaged with an inner wall of the electrode holder. Capillary-sized channels formed between this inner wall and the piston communicate fluidly with the transverse passageway. From it, any test flow stream present is partially sucked into the capillary-sized channels during an upstroke of the piston and then expelled from them, back into the transverse passageway, during the succeeding downstroke. Lacking any low velocity or stagnate areas in the transverse passageway or in the capillary-sized channels, solids cannot accumulate in the probe, making it almost self-cleaning. But, in severely contaminated waters, the electrodes in the probe still tend to foul. With the detector, electrode replacement is readily accomplished: a retaining fitting is removed, the electrode holder is slid out of the flow member, a clean electrode holder is slid into position, and the retaining fitting is replaced.