Unit for discharge and wetting of collected dust

Abstract

tests. The greatest air inflow (2-3 m3/h with a hopper vacuum of 3 kPa) was observed with a gate made of fully reinforced fabric. The significant rigidity of the walls prevented the formation of an air-tight joint and containment of the escaping dust stream. In gates made from sheet material the increased air inflow promotes the formation of folds and breaks on the walls. Nevertheless, in absolute value the inflows in these cases were significantly less (by 5-15 times) than for other gate designs. The advantage of the studied gates is easily seen in Fig. 2 where the airtightness characteristics for various types of dust gates* are given. With careful control and good-flowing, nonadhesive dust discharge-disk gates have about the same airtightness as bag gates. The poor airtightness of the VNIItsemmash bag gate was due to the high rigidity of its multilayer fiberglass-fabri c walls. The internal frame or external braces complicate the design and promote faster wear and tear. Better results were obtained for the gate in which the lower flattened part has relatively thin flexible walls while the upper part has reinforced fabric and sufficient rigidity to withstand the pressure drop. Due to its resistance to inversion and fold formation the gate can have a smooth transition from the wide upper part to the flattened lower part. In steady-state operation a dust column is contained inside the gate; its height can be approximated using the formula H~Ap/(Qd g), whore Ap is the vacuum in the hopper, kPa: Pd is the bulk density, ton/m~; and g is gravitational acceleration, m/sec 2,