This kind of Manholes is made of Intergral Relief Valve &
Vented Gas Appliance,ect.It can adjust the inner & outer
pressure of the tank itself.When the tank trips,the Intergral
Relief Valve will close automaticly so that it can protect the oil
from leakage.And when the temprature of the outer enviroment is too
high that the inner pressure of the tank will exceed to 21 ~30 kpa,
the Vented gas Appliance will open to release the pressure inside
of the tank..The maximum displacement is 7,000 m3/h to pretect it
from explosion effectively.
It’s easy to fix as well as repair.
And the manhole cover can avoid the exploision effectively.