20 Inch Steel fuel Manhole Cover
product presentation:
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.
Technique Specification：
u Positive opening pressure：6~8kpa
u Negative opening pressure：-2~-3kpa
u Setting pressure of emergency exhaust valve：23~26kpa
u Pressure resistance：0.254Mpa
Features：
u Fixed type:clamp the weld ring，load & unload quickly, with weld-skirt。
u Vent with spring can open automatically, which meet NTTC DOT406 requirements, can avoid the explosion effectively.
u Automatic sealing of the P/V vent in a roll over situation prevents dangerous and costly spillage.
u Two-stage opening allows safe release of residual compartment pressure before fully opening the fill cap.
u 250mm(10)fill hole for easy drop pipe insertion when top loading.
u Meets the NTTC DOT406 Standard
Materials：
Lever, Cover & Weld Ring:Galvanized Steel
Emergency Exhaust Valve Aluminum Alloy
Seal Ring：Nitrile or fluoro
