The Aerodyne StopTight® SG Valve is a reliable, dust-tight component for controlling flow in a bulk material handling system. The unique slide gate drive action of the StopTight prevents jamming or sticking. It also eliminates the need for racks, pinions, or cams which tend to hamper valve operation. In addition, the moving parts are self-cleaning. The StopTight’s slide plate is attached to a leaf spring assembly. As the valve closes the springs are compressed and the slide plate rises to seal firmly against the valve inlet for an airtight seal. As the springs relax, the slide plate drops down from the inlet and can be pulled clear of the inlet without obstruction. The low maintenance StopTight material handling valve is available in either manual or pneumatic operations, and is offered in a wide range of sizes. It is applicable for a variety of free-flowing materials such as chemicals, minerals, foodstuffs, and plastics.