The Vacu-Valve Platypus Trickle Valve is one of the lowest-cost, lowest-maintenance dust collector valves available, according to Aerodyne, a division of Abanaki Corp. The Vacu-Valve Platypus operates as a constant discharge valve for dust collectors, hoppers, cyclones and other equipment operating under negative pressure. Its unique duck bill design allows it to dispense free-flowing material continuously. The trickle valve is self-actuating, does not require lubrication, and has no controls or power requirements. The unit comes in carbon steel or stainless steel. The replaceable duck bill sleeves are available in a variety of options that include neoprene, high-temp and white nitrile, making the valve suitable for general use, high-temperature or abrasive material applications.