SOLIDS PUMPING APPARATUS

摘要

A pump for feeding granular material into a pressurized zone. The pump employs a feed screw (14) having flights (32) rotatable in cylinder (12). The screw flights and cylinder are tapered at the discharge end. Such pumps, while capable of sealing against a reasonable back pressure, require high power consumption. Power consumption is reduced by providing a significantly greater clearance (38) between the screw flights (36) and the cylinder in the tapered zone (43) than the clearance (40) between the flights (32) and cylinder (12) in the nontapered zone.