Bin design also involves making decisions about other system components, including: • outlet gate or shut-off valve. In general, a slide gate at the bin outlet should only be used for maintenance purposes, not to modulate the solids flowrate. Therefore, it should be operated only in the full-open or full-closed position. • number of outlets. Although a multi-outlet hopper may be attractive for production flexibility, its design can have negative consequences structurally and from a flow perspective. This also applies to hoppers that have asymmetric geometries (e.g., one sloping wall, one vertical wall). • bin vent or dust collector. Depending on the method of vessel filling, an air-solids separator may be required. • conservation vent. A dual-acting conservation vent is typically installed on thin-shelled steel tanks to avoid excessive pressure and vacuum conditions and prevent damage