8100/8200 Monitor Instruction Manual
5 Sludge Blanket Level Detection
5.1 Description
The typical sludge blanket level detection installation is in a settlement tank. The system is made up of a single or dual
sensor configuration and a monitor. There will also be associated mounting hardware, which is dependent upon the
applications requirements.
The monitor is typically mounted on a handrail on the bridge of a settlement tank. The sensor is suspended by its
cable; though it should be noted that the sensor must be fastened to the fixing point provided by the mounting bracket
and is not left to hang from the cable gland at the base of the monitor.
When mounting the monitor and sensor on a settlement tank with rotating bridge, the sensor should normally be
located on the leading edge, approximately half way between the centre and outside edge of the tank, as shown
above. Care should be taken when mounting the sensor to ensure that it does not trail into the scraper.
5.2 Sensor Installation
Once the bracket/monitor has been attached to the handrail via the saddle clamps and U-bolts and the sensor has
been connected to the monitor, it is then a matter of passing the cable through the various retaining clamps and
lowering it into the settlement tank to the desired depth at which the sludge blanket is required to be detected. When
assessing mounting options, attention should be paid to the accessibility of the sensor for calibration and
maintenance, stability of the sensor in the flow conditions present on site and it must also be ensured that when
mounting the sensor it is fully submerged at all times.
The sensor can be suspended by its cable, but the top end of the cable must be fastened to a fixed point. It should be
noted that the sensor must not be allowed to hang direct from the cable gland at the bottom of the monitor.
5.3 Monitor Configuration
When supplied the factory mid-point settings may not be suitable for the required application. If this is the case then
the following procedures should be undertaken
5.3.1 Blanket not detected
If the sensor is not detecting the sludge blanket and the green OK light remains on when the sensor is in the blanket,
take the following action:
• With the sensor in the sludge blanket, the setpoint control should be turned anti-clockwise slowly until the red
ALARM LED illuminates. This indicates that the sensor has detected the sludge blanket.
168270IM-02 Issue Date 05/01/2010 Page 9 of 14
Settlement
Tank
SLUDGE
SLUDGE
SUPERNATENT
SUPERNATENT
8100 Monitor with
Alarm LED Activated
Settlement
Tank
SLUDGE
SLUDGE
SUPERNATENT
8200 Monitor
SUPERNATENT
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