Use and characteristic:
On top of a tank car tank manhole covers installation,with functions of breathing and emergency vent.Within breathing valve internal
pressure in the process of oil tank and the pressure balance.Emergency air exhaust devices in a tremendous rise of pressure.Even in
tanker accident conditions,the respiration valves of the overflow device remained sealed,medium tank from leaking in order to
prevent major accidents.Manhole cover can be installed on the exhaust gas recycling valve,oil hole,spill-proof sheath maerial,etc.
