Product Name: rectangular insulated manhole

Rectangular manhole, manhole rectangular insulation, insulation manhole manhole is installed in the tank safety emergency ventilation device on the top, usually associated with fire, mechanical breathing valve supporting can avoid accidental reasoncreated tank sharp overpressure or vacuum, damaged tanks and accidents, have to play safe fire, is a safety device to protect the tank, especially in material storage vault atmospheric tank cap with nitrogen. With constant pressure discharge, constant pressure suction, open close flexibility, advantages of safe fire retardant, compact structure, good sealing performance, safety and reliability etc..