The Aerodyne Environmental Vacu-Valve 10-in. trickle valve operates as a constant discharge valve for dust collectors, hoppers, cyclones and other equipment operating under negative pressure; its duckbill design allows it to dispense free-flowing material continuously. The self-actuating valve does not require lubrication, controls or a power supply. It comes in carbon steel or stainless steel and is available in an open or closed design.

Aerodyne Environmental; 800-358-7546;