The WSU2 unit is a fully enclosed free standing cabinet that houses the; sample pump, nIR sensor, water flush valves and electronics enclosure. A stand-alone processor provides; timer, sequence and logic functions to maintain the measurement. The unit should be located within 30 metres of the process sample point. The drain outlet (process return) should allow easy access for sampling for lab. Calibration checks. Dual sample switching valves can be fitted to the inlet to allow sampling of two points sequenced at 90 second intervals. The unit requires electrical power, air supply, flush water, instrumentation and process connections.

A more detailed specification of the unit is available separately.

The installation arrangement should be designed to ensure that a well mixed, representative sample is taken and that flocs or deposits are prevented from contaminating the sensor.

A sample taken from the 1^st wire tray will give an immediate indication of changing whitewater solids. A sample from the whitewater silo can contain some additional solids from headbox excess flow lines. The sample point has to be positioned correctly to avoid entrained air. Piping should have swept bends and be sufficiently large to allow a good flow rate during back-flushing, restrictions in the pipe lines should be avoided to prevent deposit build-up. Normally 25mm (1”) bore reinforced hose is used. The minimum bore for pipe fittings is 20mm. Isolating valves should be quarter turn (90°) ball valves.