Unlike rotary airlock valves which are driven by either an electric motor or a gas or air-powered motor, trickle valves require no external power source and are therefore well-suited for use in mechanical trenchers, where a dust-free environment in the pinnacle truss and axle bore is required for smooth operation.
Because these valves have no way to force clogs through, they are only recommended for use with dry and relatively dense, free-flowing materials such as sand, fly ash, and cement.
The negative pressure of the dust collection system collapses the sleeve on itself, creating an airtight seal.
The weight of collected material above the valve forces the sleeve open to allow a steady discharge.
Trap door trickle valves have one moving part, a hinged flap plate to maintain a seal between the hopper and the discharge.