Patent ID: 7694559

Claim:
Apparatus for detecting a level of a surface of a liquid in a container having an upper opening, the apparatus comprising: an enclosure including a lever moveable between an upward unlocked position and a downward locked position; a support housing mounted to said lever, said support housing being adapted to mate with the upper opening of the container when said lever is in said downward locked position, and the container being freely movable into and out of the support housing when said lever is in said upward unlocked position; primary liquid level sensing means mounted in said support housing for non-intrusively measuring the level of the surface of the liquid in the container, wherein said primary liquid level sensing means comprises an optical sensor device mounted in said support housing for non-intrusively measuring the level of the surface of the liquid in the container, said optical sensor device including a light emitting device for projecting incident light on the surface of the liquid in the container, and a light detecting device for detecting said incident light reflected from the surface of the liquid in the container; and secondary liquid level sensing means mounted in said support housing for intrusively sensing a predetermined level of the surface of the liquid in the container for preventing accidental overflows in the event of a malfunction of the primary liquid level sensing means.