When a delivery hose is connected to the filling point at a service station there could be a potential difference between the couplings which can cause an ignition. At that moment there is a risk of an explosive environment around the open filling coupling of the ground tank. A source of ignition and a potentially explosive environment are the two basic risks handled by the ATEX-directive.
Only open when connected
The main function HSE Interlock valve is to keep the filling point (and the ground tank) closed whenever the delivery hose is connected or disconnected. This is done via mechanical interlock feature which contains the explosive environment within the ground tank.
The HSE Interlock valve secures the filling point against a possible explosion. The valve is user-friendly, well proven and protected by patent 05 02 129-0.
The connection flanges are easy to change and adapt to the requirements of the local market, as is the interlock lever that differs depending on the flanges. The HSE Interlock valve is availabe in 2”, 3” and 4” versions.
H = Health
When opening the filling coupling, any overpressure, no matter how small, will force the fuel fumes from within the ground tank out into the face of the driver delivering product. This is avoided by using the Interlock valve resulting in a much improved working environment for the driver.
S = Safety
As explained earlier, the risk for an explosion from a spark caused mechanically or due to a potential differences between the hose coupling and the filling coupling, are eliminated by the Interlock valve.
E - Environment
The VOC directive (94/63/EC) from 1994 on the control of volatile organic compound (VOC) emissions resulting from the storage of petrol and its distribution from terminals to service stations clearly supports the environmental feature of an Interlock valve in preventing emissions from an open filling point.