Empty drum detecting apparatus

Claim 1

An empty drum detecting apparatus interposed between a liquid supply drum and process equipment utilizing the supplied liquid, comprising a supply line to extend remotely from such a supply drum, a liquid pump and an inlet line to the pump, the pump being adapted to supply liquid to such process equipment, manifold means defining an elongate upright manifold chamber to contain a quantity of the liquid and comprising an upper portion and a lower portion below said upper portion, sensing means adjacent the manifold chamber and producing first and second indications when the liquid level in the manifold chamber respectively rises and lowers relative to the sensor, the supply line being connected into the manifold chamber below the upper portion thereof, an outlet line connected to the lower portion of the manifold chamber and also connected to the inlet line for supplying liquid to the pump, and a shunt line with a restriction to liquid flow therein, the shunt line being connected between the upper portion of the manifold chamber and the inlet line to allow the pump to draw gas and liquid from the upper portion manifold chamber as liquid is also being drawn by the pump from the lower portion of the manifold chamber.