SGB devices are used to monitor tightness of interstitial spaces of double-shell tanks.
There are two main types of such devices:
- positive pressure marked DL
- vacuum marked VL.
A pump which generates positive pressure in DL type systems and vacuum in VL type systems is the integral part of the system.
Positive pressure devices are used primarily in underground tanks. For aboveground tanks, vacuum systems are recommended to be applied.
The quantity and power of devices are selected on the basis of the value of the monitored space in the tanks.
- simple assembly of the device
- maintenance-free operation of the device
- easy data analysis – an alarm in the event of a leak
- one device may support a number of tanks up to 8 pcs – connections on the distribution board
- the measuring unit can be installed outside the EX zone in a room available for personnel
- German quality – reliable operation
The positive pressure leak indicator, e.g. most commonly used SGB DL280, is connected to the space with pressure and measuring cables.
Positive pressure generated by the pump is measures and adjusted by the pressure sensor.
When the operating pressure is reached, the generation of positive pressure is switched off.
During normal operation, indications of the leak indicator ranges from those limit values, with short periods of operation and longer downtimes, depending on the degree of tightness and temperature fluctuations throughout the system.
If the limit values are exceeded, the alarm is triggered.
The vacuum device, e.g. most commonly used SGB VL330, is connected to the space with two cables (pressure and measuring) as is the case for positive pressure devices.