The SmartPurge II (SP2) is a highly flexible electronic purge and pressurization system suitable for a wide range of flow rates and duties. It can operate as either X, Y or Z purge, and in leakage compensation (LC) or continuous flow (CF) modes.  

The system comprises the Control Unit (CU) and the Air Supply Unit (ASU). The Control Unit contains the logic to monitor and control air flow, pressure and purge timing, and provides the system inputs and outputs (I/O). Functions such as purge mode, purge time and I/O can be configured on the CU. The CU also contains the relief valve to measure purge flow and provide over-pressure protection for the enclosure.

The Air Supply Unit has two configurations. For LC the valve is operated by the SP2 control unit to switch between purge flow and LC flow rate. This valve is intrinsically safe. For CF applications, the ASU is manually operated and set to the required level that will be used during and after purge.

The SP2 provides power switching to the purged enclosure of up to 6A. If higher loads are required, then Expo recommends the use of a SmartPurge Interface Unit (SIU).

The SP2 is also available configured for use with fan air, where compressed instrument air is not available - for further details of the SP2-F see operating & maintenance manual ML483.