The Vacu-Valve Armadillo is a closed construction airlock valve that provides positive seal under hoppers, cyclones and dust collectors. Because this dust-discharge valve requires no controls, lubrication or power source, it is both energy saving and maintenance-free. The unit's duckbill valve design allows free-flowing continuous discharge, automatically adjusting to the desired vacuum. The product is offered in carbon or stainless steel construction with sleeves available in neoprene, viton, and white nitrile, making it suitable for general use, high-temperature or food grade applications. The unit has a durable enclosure making it useful in controlling dust in windy outdoor applications or in applications where the valve is not positioned close to the collection container.