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and prevent pollution

Our Total and Free Chlorine Analysers utilise the very latest and best chlorine sensors available in the world today

Chlorine Sensor


Key Features

  • Amperometric sensors
  • No chemical reagents
  • Stable and reliable
  • Suitable for all potable, process and salt waters

Lower costs of ownership

  • Up to a year between maintenance
  • Up to 3 months between calibration
  • Up to 15 years life


The ORAKEL range of Residual Chlorine Analysers, Residual Chlorine Controllers and Residual Chlorine Monitors are membrane devices which are insensitive to changing pH, use no reagents, are extremely stable, and have reduced maintenance and reduced whole life costs.

How it Works

The membraned amperometric chlorine sensors are enhanced with a third, reference electrode which eliminates zero drift.  Its unique design means that pH correction is not usually required at all, completely eliminating reagents.

In addition to the state of the art potentiostatic chrono-amperometric free chlorine and total chlorine sensors, the ORAKEL range of residual chlorine analysers has all the functionality that you need, and more.


The ORAKEL chlorine analyser range is particularly suited to working in sites where reliability and ease of use are most important.

Water Treatment applications:

  • Chlorine Dosing
  • Cooling Towers
  • Food Preparation
  • Paper Mills
  • Remote Sites
  • Secondary Chlorination

Chlorine sensor options:

  • Free Chlorine
  • Total Chlorine
  • Free Chlorine ‘zero’

The ORAKEL Chlorine sensor can be installed in a variety of auxiliary flow cells and self-cleaning devices.

pH Compensation

For some applications with high and variable pH, pH compensation can improve the accuracy of the chlorine readings. For pH compensation to be valid it must be done with the highest quality pH sensors and with chlorine sensors that have a reduced susceptibility to varying pH, such as those used in the ORAKEL range of chlorine analysers.

An alternative to pH compensation is the use of CO2 to suppress the pH such that changes in the pH of the sample do not affect the chlorine reading.


Membrane covered potentiostatic chrono amperometric three-electrode system

Total Chlorine or Free Chlorine

0.01-2mg/l, 0.01-5mg/l, 0.01-10mg/l, 0.01-20mg/l, 0.5-200mg/l (free only)

0.01mg/l (ppm) (0.1 on 0-200mg/l ranges)

Better than ±0.05mg/l

-1% per month (without calibration)
Working electrode: Gold
Counter electrode: Stainless Steel

Reference electrode
Silver / silver halide

Membrane material
Micro-porous hydrophillic membrane

Flow rate
Approximately 0.5l/min (min 0.25l/min)

Temperature range
0 to <45°C

Temperature compensation
Automatically by an integrated thermistor

pH 4 up to pH 9

First-polarisation time
2 hours

Re-polarisation time
30 min

Response time
T90: approx.120 seconds

Zero-point adjustment
Not necessary

Manual using Electrochemical test kit or DPD test kit

Housing material
PVC, silicone, polycarbonate stainless steel

Diameter approx. 25mm, length 175mm

Maintenance intervals 
Membrane:     Once a year (depending on water quality)
Electrolyte:     Once a year (depending on water quality)

High levels of other oxidants such as Ozone and Chlorine Dioxide

Learn More

Find the most up to date product information and available downloads

Find the most up to date product information and available downloads

Datasheets – EN:
MMS D010 – ORAKEL Chlorine
MMS D017 – ORAKEL control unit

Datenblätter – DE:
MMS D022 – GmbH ORAKEL Chlorine
MMS D029 – GmbH ORAKEL Control Unit

Watch our Predictive Data Monitoring Video here

Read More

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