High-velocity relief valve (pressure vacuum valve) is the controlled venting system which is necessary for oil tanker and chemical tanker. The series of DF-type P/V valve is a new generation production without vibration and anti-collision...The pressure/vacuum valve is installed on the vent pipe of oil tanker and chemicals tanker. It is the only entry and exit for liquid cargo tank. 

Main performance parameter

Remarks:

1.The high-velocity relief valves with different specification have the same diameter and performance parameter;

2.The opening pressure of the vacuum valves are -3.5kpa; the opening pressure of the pressure valves on the oil tank is 14kpa,on the chemical tank is 20kpa.The opening pressure of the pressure may be different, but the differences of opening pressure and flow range if the pressure valves have the same diameter.