With an installed pressure/vacuum valve at the vent pipe displacement
of (VOC) vapours are significantly reduced and the idea of environmental protection is maintained.
To open a p/v valve pressure has to be created up to e.g. 30mbar.
This 30 mbar pressure doesn’t sound like much, but in nearly empty 10.000 litre storage tank this pressure can create up to 300 litre of (VOC) pressurised vapours.
This 300 litre of (VOC) vapours will escape as soon vapour recovery stage IB or/and the delivery point has been opened. The tanker driver is exposed to these vapours several times every day over yearSame amount of gas will hit the engineer during service and maintenance.
This cannot be a healthy working environment.
With the Pressure Release Valve installed parallel to the vent, the pressure in the storage tank can be relived to the vent.
That means, that before opening the storage tank, the tanker driver, service engineer or station manager can release the tank pressure manually through the bypass valve. After realising the pressure the valve is closing automatically and the pressure/ vacuum valve is in charge again.
This solution provides a safer and healthier environment for both the employees and members of the public.