Self-locking self-adjustment manhole cover

1. Pressure-bearing:210KN-600KN (It is professional to press Europe ) EN124 standard and 97S5012 standard) 2. Material:ductile iron 3.In order to prevent the gas or water from leaking out special airproof capability is available city water supply drainage pipeline well gas well , heat supplied 4. Design pressure spring lock may prevent that well cover pulsates; Shockproof washer may prevent that well cover shakes and avoids noise Applicable place (for certain activities) :Expressway and city trunk road , national highway: Wait for circular well 5. lock with security key a saftety block existes applied on the frame to avoid the accidental closure of each lid 6.Also can product s according to drawingand welcome to visit our factory anytime you want