TU 8355/8555

High Turbidity and Suspended Solids (MLSS) probes

  • Description
  • Technical specifications

These unique probes have been designed to measure high Turbidity and Suspended Solids based on backscattering technology. The probes are available for submersible and in-pipe installations.
The measuring system consists of:

  • Infrared light source,
  • Detector of scattered light by suspended particles,
  • Detector of the clean lens status,
  • 2-wire 4/20 mA analog output,
  • RS 485 digital output
  • Nozzle for the autoclean by external pressured air (TU 8355).

Through commands from the Personal Computer hyperterminal, the serial interface allows the measuring and check signals transmission, the scale selection, the analog or digital operating mode selection, the zero and sensitivity calibration.

Thanks to its 4/20 mA isolated output, the probe can be directly connected to a PLC or data logger, and configured in FTU, g/l, % or other.
The probe can be connected to B&C Electronics controller BC 6587, which provides the power, the measuring readout, 2 set-points, the alarm relay and the holding function for an external cleaning cycle.

The most common applications of this probe include: water quality monitoring, municipal and industrial wastewater treatment and aquaculture.

Principle of operation

The Turbidity and suspended solid measurement follows the backscattering method. A light beam is sent in the sample through an optical lens. The backscattered light by a suspended particle is collected by the probe through a second lens, detected and converted in an electric signal proportional to the Turbidity of the sample.
The probe uses an infrared light and the measuring is not affected by the colour of the sample.

  • Scale 0/100 – 0/1000 – 0/10000 FTU
  • Sensitivity NTU 70/130 %
  • Zero NTU ± 10 FTU all scales
  • Power supply 9/36 VDC
  • Analog output 4/20 mA isolated current Loop
  • Load 600 Ω max. at 24 VDC
  • Digital output RS 485
  • Room temperature -5/50 °C
  • Max. pressure 1 Bar at 25 °C
  • Autoclean by pressure air 3 bar max (TU 8355)
  • Dimensions TU 8355 L=165 mm total, D= 60 mm
  • Dimensions TU 8555 L=143 mm total, D= 40 mm
  • Body PVC
    Cable 10 m (100 m max.)
    Protection IP 68