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Inline Turbidity Transmitter for Clean Water Applications

inline turbidity transmitter for drinking water TU8325

The TU8525 is a Turbidity Sensor with integrated electronics designed to output a 4-20mA signal proportional to the turbidity measurement. The TU8525 is designed for mounting inline into pipework or for mounting into a sample line from pipework.

The TU8525 uses an infrared light emitting source and a 90° photo-receptor to measure back scattering in accordance with ISO 7027EN 27027.

Manufactured in PVC with IP68 rating, the TU8525 is designed to be mounted directly into pipework or into a sample line such as our model TU910 inline probe holder.

4-20mA Inline Turbidity Transmitter

The TU8525 is a unique piece of equipment. It combines a nephelometric turbidity sensor, complete with integrated electronics, in order to provide an isolated 4-20mA output, proportional to the turbidity measurement.

The industry standard 4-20mA output signal is isolated into 600Ω and the instrument has been designed to give easy integration with a wide range of control equipment.  The 4-20mA signal is simple to connect to a PLC, digital Chart Recorder, universal controller or even our online Data Logger.

The 4-20mA output is loop powered, which means that the same two wires which carry the 4-20mA signal are also the same two wires which power the device.  This makes integration with PLC's and other control equipment incredibly straightforward.

Turbidity Transmitter with NTU Ranges

The TU8525 is designed for water quality analysis and is suitable for drinking water applications, raw water applications and water treatment applications. The ranges available with the TU8525 are as follows:-

Please note:- Nephelometric Turbidity Units shows as NTU

Turbidity RangeTurbidity Resolution
0 - 4.000 NTU 0.001 NTU
0 - 40.00 NTU 0.01 NTU
0 - 400.0 NTU 0.1 NTU

As a microprocessor driven device the TU8525 can communicate with a personal computer using a hyper-terminal client and serial interface. By accessing the device the ranges can be adjusted in the instrument software, allowing the same device to measure from as low as 0.001 NTU through to 400.0 NTU. We're also able to factory calibrate the measuring range of the instrument prior to it being despatched.

The TU8525 also offers a digital RS485 output which can be used to connect to a supported device.

Inline Turbidity Transmitter

The TU8525 is designed to be mounted either inline directly into pipework using a locking nut, or to be installed into a sample line cell. This is where a secondary line runs for the primary pipework, through the sample line flow cell, and then the sample discharges to drain.

Turbidity measurements in very clean water, such as drinking water, are susceptible to false positives from bubbles in the measured solution.  As bubbles are caused by water discharging to atmospheric pressure, flow cell TU910 includes a tightening tap to allow the sample flow cell to remain pressurised and prevent bubbles affecting the measurement.

When installed directly into pipework or the sample cell, the TU8525 in designed to operate to pressures up to 6 Bar.  In addition, using the infrared spectrum, the TU8525 is not affected by the colour of the measured solution within the pipework and should not be affected by bright light blinding the photoreceptor.

Inline Turbidity Transmitter Features & Benefits

The TU8525 is a genuinely unique instrument.  Designed to be permanently mounted into pipework or a sample line such as TU910 to give continuous turbidity readings and outputs a 4-20mA signal proportional to the turbidity measurement.

Designed to offer precision measurements even when measuring very low turbidities, the TU8525 can measure as low as 0.001 NTU or as high as 400.0 NTU in the same cell.  Using a personal computer hyper terminal, the serial interface allows the range to be changed from 0 4.000 NTU to 0 - 40.00 NTU or 0-400.0 NTU.

The PVC body and IP68 rating allow the cell to be permanently mounted into pipework and withstand a pressure of up to 6 Bar.  The isolated industry standard 4-20mA can interface with a wide range of PLC's and other control instruments and is easily connected using just 2 wires.

The turbidity measurements follow the standard nephelometric back scattering methodology (ISO 7027 - EN27027) and the infra-red light is not affected by the colour of the sample.

TU8525 Inline Turbidity Transmitter Specifications

  • Specifications


    Inline Turbidity Transmitter

    Model No:- TU8525

    Turbidity Range & Resolution:- 0-4.000 NTU with 0.001 NTU resolution

    Turbidity Range & Resolution:- 0-40.00 NTU with 0.01 NTU resolution

    Turbidity Range & Resolution:- 0-400.0 NTU with 0.1 NTU resolution

    Zero NTU:- ±0.400 NTU all ranges.

    Sensitivity:- 70% / 130%

    Materials and Rating:- Manufactured in PVC to IP68

    Analogue Output:- 4-20mA isolated into 600Ω

    Digital Output:- RS485

    Operating temperature:- 0-50°C

    Operating Pressure:- 6 Bar at 25°C

    Autoclean:- By air pressure max 3 Bar

    Power supply:- 9 / 36 VDC

    Weight:- 800 grams

  • Features


    • Inline Turbidity Sensor for installation into pipework or a sampleline to give continous or online Turbidity measurements.
    • Nephelometric Turbidity measurements (ISO 7027 - EN 27027) give results in NTU. Ideal for water quality analysis.
    • Exceptional accuracy even at very low ranges, a resolution of just 0.001 NTU and a maximum scale of 400.0 NTU all in the same compact design.
    • Simple to install and connect to measurement and control equipment - the 4-20mA current output is loop powered, meaning that the same two wires that transmit the signal also transmit the measurement signal.
    • The TU8525 has no moving parts and requires minimal periodic calibration and maintenance.
    • Factory set or configurable via computer - the TU8525 can be periodically calibrated using a personal computer and the instrument can be re-ranged for alternative applications as required.
    • Designed specifically for precision measurements in drinking water analysis, raw water measurement, and for water treatment applications .
  • Data Sheets

    Data Sheets


More Information