FIELD: chemical filament production equipment. SUBSTANCE: double- mode ventilation apparatus has recycling airduct, periodic intensified suction airduct, outlet pipe and valve with gate and seat. Gate is connected with drive. Outlet pipe has opening positioned in its side surface behind valve downstream of reactant suction flow and may be cut off by gate. In the process of producing viscous filaments, vaporous reactants are periodically discharged from machine for recycling through airduct, with valve of intensified suction airduct being cut off. Air is discharged from shop through opening. EFFECT: increased efficiency in ventilating air of hazardous working zones of shops, wider operational capabilities and enhanced reliability in operation. 1 dwg
