Experience With Nonmechanical Solids Flow Control Device in the Waste Calcining Facility

Large volumes of radioactive granular solids are being safely and efficiently handled, pneumatically, on a production scale in the Waste Calcining Facility at the Idaho Chemical Processing Plant. The low-pressure system uses no mechanically operated equipment, and hence has required minimal maintenance. Several unique devices in nonaccessible areas control and direct the flow of the solids from a cyclone and a fluidized bed to underground storage bins. A flow control valve is used to divert solids from a common supply header to any selected terminal by using an airstream to disturb the solids angle of repose. A pneumatic ejector is used for the dual purpose of removing solid fines from a low pressure cyclone and of preventing a backflow of air into the cyclone which would reduce its air-solids separation efficiency. An air purging system is used in the solids removal line from the fluidized bed to control solids flow, and thereby regulate the bed level in the vessel. The absence of moving parts in these devices makes them particularly attractive for use where reliable operation and minimum maintenance is of utmost importance.