1)  Manhole Cover is equipped on the top of tank truck.

2)  It is the entrance of fluid transfer operation inspection and maintaining the inside tank. It can protect the tank when involving in an emergency.

3)   Under normal practice, vent is closed When loading and unloading and temperature variation, it will cause the pressure variation inside the tank, such as air pressure and negative vacuum pressure, the vent of manhole cover will be closed automatically in order to keep the tank under a normal pressure.

4)   When involving in emergency, such as a car accident, the Emergency Exhaust Valve will open the inside tank, meets the setting, in order to prevent explosion.

5)   It is internationally accepted, and specified, by oil companies  around the world to assist with the safe transportation of petroleum based products.