1) Zero pressure accumulation conveyor
A type of powered conveyor accumulation. Zero pressure accumulation is that which occurs when the driving force is completely removed form the load. This is usually accomplished by way of sensors in combination with various mechanical means such that when a load is stopped on a sensor, the driving force in the zone behind the stopped load is dropped away. When the next load is driven into the now dead zone, it too will stop, causing a like chain reaction upstream, or until such time that the first stopped load is released and moves on. Discharge from an accumulation point can be either one load at a time or a so-called slug discharge, where a pre-specified number of loads are released at one time.