Marine Pressure Vacuum Relief Valve for Cargo Oil Tank
for cargo oil tank (or High Velocity P/V valve, for short) is generally used in the relief system of the oil tanker and chemical tanker, according to the current regulations IMO and IBC.The purpose of the high velocity valve is to provide automatic control of pressure differentials during liquid cargo ship loading, voyage,ballasting and deballasting without any manual operation, also, it provides auto-protection against fire and explosions on deck. Additionally in the event that the inert gas system can not supply gas promptly, the vacuum valve can auto open to protect the tank against excessive vacuum when deballasting on dock. Normal, when the pressure risen in tank because of temperature or loading, the pressure valve open automatically and vent gas. When the pressure of tank come to pressure differentials, the vacuum valve or pressure valve all can be automatic resetted. If an ignition occurs outside the tank space, the flames will be quenched in the flame trap.
Specification:
Material: Cast Steel or Stainless Steel
Flange Standard: GB, JIS, DIN, ANSI, BS
Opening Pressure of Vacuum Valve: -3.5kPa
Opening Pressure of Pressure Valve 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 is unapparent if the pressure valves have the same diameter.
* When the liquid cargo ships need to load the goods of the propylene oxide class, with the stainless steel high velocity P/V valve. The valve manufacturing materials for 304, 304L, 316L quality stainless steel, pressure valve opening pressure is generally set at 60KPa vacuum valve.
Type |
kPa
Designed Openging Pressure |
kPa
Rated Working Pressure |
Velocity m/s |
M3/h
Flow Rate |
Pressure valve |
Vacuum valve |
Pressure valve |
Vacuum valve |
Pressure valve |
Vacuum valve |
| DF50 |
14-21 |
-3.5 |
21.0 |
-7.0 |
>30 |
>300 |
>300 |
| DF65 |
>400 |
>400 |
| DF80 |
>600 |
>500 |
| DF100 |
>800 |
>600 |
| DF125 |
>1000 |
>800 |
| DF150 |
>2500 |
>2200 |
| DF200 |
>3000 |
>3000 |
| DF250 |
>3500 |
>3000 |
flange standard:GB2506-2005
pressure range:14kPa-21kPa
vacuum range:-3.5kPa
executive standard :ISO 15364,MSC/Circ.677,MSC.1/Circ.1324
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