Multi-point refractive liquid level sensor

An apparatus is used for sensing liquid level in a vessel at multiple levels and with variable resolution using optical properties. Known electrical optical sensing devices are not adequate for applications where multiple level, fine or variable resolution sensing are desired. The subject liquid level sensor includes a mounting apparatus adapted for insertion into the vessel, for containing the electric circuit, and for filtering the liquid entering the sensor. In addition, the sensor includes an array of sensing elements electrically connected in parallel and attached along the mounting apparatus spaced from one another at preselected locations. The sensing elements are adapted to deliver a plurality of electric signals in response to the absence of liquid at the level of the respective sensing element. The electric signals are then summed by an amplifier, which then delivers a resultant liquid level signal.