In many countries, safety devices are required for the monitoring and protection of fuel oil in buried tanks. To prevent the leakage of fuel, double-walled tanks or plastic covers (for older, single-walled tanks) are used. 

In between the double-wall a vacuum is built up and monitored by a pressure detector. Pressure variations and very small leakage on tube fittings and threaded joints are constantly leveled by the pump integrated in the monitoring device. The pressure detector switches on the pump when a minimum pressure is reached and switches it off when a maximum pressure is reached.

If a bigger leak occurs, the pump cannot build up the vacuum and it will run continuously. The pressure increases and a built-in alarm as well as an optical alarm will go off. Leaked oil will be held in the monitoring room by the vacuum and the pump.

Overpressure Leak Detector D 9