High-Velocity Relief Valve with Flame Arrester at Pressure Valve Port

High-Velocity Relief Valve with Flame Arrester at Pressure Valve Port

Standards, uses and main characteristics

DF-ISO type pressure/vacuum valve (also known as high-speed vent valve) is designed, manufactured and tested according to the following standards and specifications.

1. IMO. MSC/Circ.677 "Revised Standard for Design, Test and Installation of Devices to Prevent Flame from Entering Tanker Cargo Tanks";

2. ISO15364 "Pressure/Vacuum Valve for Ships and Marine Technology Cargo Tanks";

3. IMO.MSC/Circ1324;

Refer to EN 12874-2001 “Flame Arresters - Performance Requirements, Test Methods and Limits For Use”. The pressure vacuum valve is the only outlet and inlet for oil tankers and chemical tankers. It is installed at the top of each compartment. When the liquid cargo tank is loading, the pressure valve automatically discharges the mixed gas in the tank vertically upward at a speed greater than 30m/s; when unloading, the vacuum valve automatically replenishes air into the tank to prevent the liquid cargo tank from overpressure and depressurization. The pressure vacuum valve manufactured in accordance with the above standards can prevent flames from entering the liquid cargo tank even in the working state.

The test of our cargo oil tank pressure/vacuum valve is carried out in a laboratory approved by the national competent authority, and has passed all the tests of the following items according to the above standards, and has been recognized by China Classification Society and some foreign classification societies.

1. Fire resistance test; 2. Backfire test; 3. Freezing test; 4. Corrosion test; 5. Flow test.

Series DF-ISO type pressure vacuum valve DF50, DF65, DF80, DF100, DF125, DF150, DF200, DF250, due to the special design of the pressure valve, the valve will only be fully opened when the system pressure stably reaches the set opening pressure. At normal loading rate, after the valve is opened, the pressure of the pipeline and the cabin system will drop by about 20% to 50%, and then it can work stably and maintain an outlet flow rate of 30m/s. During operation, the system pressure will not increase or decrease suddenly. At the loading rate of the minimum to maximum flow rate allowed, the high-speed outlet valve will not collide or oscillate. This series of valves can also be installed with a magnetic control mechanism to deal with the problem of valve vibration during navigation, which can minimize the steam loss during navigation.

The leakage of the DF-ISO series pressure vacuum valve is basically zero at 80% of the set working pressure. It can be selected for loading goods that require zero leakage. It is one of the most advanced valves in the world.

The series of valves can work normally in an environment of 20℃ ~ +60℃. When the valve port is frozen, it can work normally after breaking the ice.

Note: During the freezing test of the DF-ISO type pressure vacuum valve, turn the lifting handle (11), the thickness of the manual ice breaking should not exceed 5mm, and the ice should be cleared after breaking the ice so that the valve can work normally.