Abstract: A dust trap is disclosed including a pair of coaxially mounted dust valves. Each valve has a valve body with a flow path therethrough. A cylindrical seat is mounted in each body and a frustro conical flapper is provided having an angled surface which seats against a beveled internal surface of the seat. The flapper is mounted on an actuator shaft and rotates from a seated position to an open position substantially parallel to the flow path. A deflector is mounted in the seat and a wear plate is provided along an internal wall of the body opposite the actuator shaft so that dust passing through the valve does not impinge on the open flapper. An access door is also provided to inspect, clear or replace the flapper and seat.

Abstract: A dust trap having an annular valve seat and a pivoted valve flap closing the same including an off-center connection between the actuating means for said pivoted flap and said flap thereby to lessen the force required to open the valve passageway against the force of vacuum.