There are a number of reasons these spills occur. Sometimes it is human error, but often it is equipment malfunction. Malfunctions may occur if the AC valve sticks open, the plant automation malfunctions, an AC gate failure, a mechanical switch failure, or an inattentive plant operator. The equipment presently used to prevent spills are inaccurate and use mechanical devices that are not tested and frequently malfunction.
Libra has developed the HWD100 (High Weight Detector) that is independent of everything except the Digital Weight Indicator. The HWD100 is connected to and independently monitors the weight in the AC hopper via an A&D Model 4323 digital weight indicator. If the weight in the AC hopper exceeds the maximum allowable weight you have determined, the HWD100 removes the electrical power to the AC pump. If the pump pressure is removed, no additional liquid will flow, even if the AC valve is open.
The HWD100 plugs directly into the A&D 4323 Digital Weight Indicator and only requires two wires from the AC pump. The system is easy to use and can be installed by plant personnel.