What is the most likely cause of a mechanical bar screen continually shearing pins?

The most likely cause of a mechanical bar screen continually shearing pins is higher than average flows causing rapid buildup of solids. When the flow rate is significantly above normal levels, it can lead to an increased volume of debris and solids being captured by the bar screen. This situation creates a scenario where the screen is overwhelmed by the amount of material it needs to process.

As the solids accumulate more quickly than the screen's cleaning mechanism can remove them, excessive force is exerted on the screen's components, including the pins. This constant strain from the material buildup and the mechanical action required to clear it can result in the shearing of pins used in the screening system. This emphasizes the importance of managing flow rates and understanding the capacity of the equipment in order to prevent mechanical failures like this one.

Proper understanding and maintenance of bar screens is critical in wastewater treatment to ensure they function efficiently and to prolong their operational lifespan.