The High-Velocity Vent Valve, also known as the High-Velocity Pressure/Vacuum Relief Valve, is a gravity-operated automatic pressure control device for cargo oil tanks, integrating a vacuum valve, pressure valve, and high-velocity discharge mechanism into one unit.
Its function during cargo loading allows for the discharge of large volumes of vapor-gas mixtures from the cargo oil tanks.

Once the valve opens, the exhaust velocity at the outlet exceeds 30 m/s under any flow condition. During unloading, it enables the intake of large amounts of air into the cargo oil tanks to balance tank pressure;

during gas freeing operations, it allows hydrocarbons to be discharged through this valve from the cargo oil tanks.

Under normal sailing conditions, minor temperature fluctuations result in the automatic release of small amounts of vapor or the intake of small amounts of air into the cargo oil tanks.

In the event of a fire on the tanker's deck,

this high-velocity vent valve prevents external flames from entering the protected compartments.

Therefore, the high-velocity vent valve serves as the venting device for oil tankers and chemical tankers.



The design, manufacturing, and testing of this valve comply with GB/T19699-2005,



ISO15364:2000 "Ships and marine technology—Pressure/Vacuum valves for cargo tanks," IMOMSC/Circ.677

"Revised standards for the design, testing, and installation of devices to prevent the passage of flame into oil tanker cargo tanks," and CB/T604-93 "Fire-resistant screens for oil tank vent pipes."



The high-velocity vent valves produced by our company feature a large lift when reaching the discharge pressure, with no flutter or impact during operation, ensuring safe and reliable performance. The specifications range from D**0 to 300.



Type testing for this product includes static water pressure test, air tightness test, pressure valve

opening and closing pressure tests,

vacuum valve opening and closing pressure tests,

corrosion resistance test, freezing test, pressure valve flow performance test, vacuum valve flow performance test, metal flame screen afterburn test,

high-velocity vent afterburn test and endurance burning test,

and gas freeing cap afterburn test.

The PV High-Velocity Vent Valve, also referred to as the High-Velocity Pressure Relief Valve and Vacuum Valve, is used in oil tankers and chemical tankers' liquid cargo holds. It automatically controls the pressure within the cargo tanks during loading, sailing, ballasting, and unloading without any manual intervention, preventing overpressure or vacuum in the cargo oil tanks. Additionally, it provides automatic fire and explosion protection on the deck. When the pressure in the liquid cargo tank exceeds the set value, the pressure valve opens automatically to vent. Once the internal and external pressures equalize, the valve disc instantly resets. If a spark occurs outside the tank while the pressure valve is operating, the high-velocity airflow from the valve port will blow the spark away or extinguish it. When the vacuum valve is operating (i.e., during suction), any external spark will be extinguished on the valve's flame screen.