Liquid concentration optical sensor

摘要

An improved optical concentration sensor is provided for use with continuous ink jet printers. The optical concentration sensor has an optical cell which can contain a fluid (30) to be tested, at least one light source (22) for passing light through the fluid, at least one light detector (26) for detecting light transmitted through the fluid, and electronics for monitoring a first output from the light detector and providing a second output related to concentration of the fluid. Specifically, the improvement comprises curved inner surfaces of the optical cell walls (12a,12b) for producing at least one region with a narrow gap for transmission of light through the fluid and regions with wider gaps for more efficient flow of fluid through the cell.