Abstract: An apparatus for is disclosed for detecting low liquid level in a bottom-draining container (12), the apparatus including a spout (14, 48) extended outwardly from the container, the spout having a central bore (18) through which liquid can drain from a bottom of the container; at least one guide member (26, 56, 62) positioned in the spout; at least one float (38) mounted for movement in the spout along the guide member, the float being buoyant in a liquid to be drained from the container; a source (42) for directing a beam of radiation into the spout along a path intersected by the float when a liquid drains to a preselected level within the spout; and a device (44, 46) for detecting when the float intersects the beam. The guide member may be omitted in one embodiment.

Abstract: An apparatus for is disclosed for detecting low liquid level in a bottom-draining container (12), the apparatus including a spout (14, 48) extended outwardly from the container, the spout having a central bore (18) through which liquid can drain from a bottom of the container; at least one guide member (26, 56, 62) positioned in the spout; at least one float (38) mounted for movement in the spout along the guide member, the float being buoyant in a liquid to be drained from the container; a source (42) for directing a beam of radiation into the spout along a path intersected by the float when a liquid drains to a preselected level within the spout; and a device (44, 46) for detecting when the float intersects the beam. The guide member may be omitted in one embodiment.