• Drinking water
  • Iron removal processes and residual coagulant monitoring
  • Industrial wastewater
  • Measurement of effluents and wastewaters
  • Boiler feed water
  • Corrosion control
  • Cooling water
  • Surface water


The 3S colorimeter is a compact analytical instrumentation for online analysis and process monitoring. The colorimeter is based on a color-developing chemical reaction carried out inside the analyzer's glass cell. The sample, coming from an external reservoir or process stream is autonomously grabbed by the instrument and mixed with the appropriate reagents to make the reaction happen. The analyzer uses an LED light source and a photodiode to photometrically measure the developed color intensity (absorbance). The absorbance is proportional to the concentration of the target chemical species (analite).


  • Low reagents consumption and analytical reliability thanks to our custom designed miniature peristaltic pumps
  • Dual compartment design to guarantee a complete separation between the electronics and the hydraulic section
  • Color touchscreen to show the last measured value clearly, and to set all the options and settings via an user friendly interface
  • Datalogger function with data history in graphical form and USB download
  • Automatic calibration, validation and cleaning to reduce down time and operator intervention, their frequency can be freely set by the user
  • Fully integrable in industrial automation via the analog outputs (2 x 4-20 mA channels), digital output (2 relays + ModbusRTU) and digital input (voltage free contact)

Iron is ubiquitous on Earh's crust, it can be found in varying amounts in surface waters. It can can also be found in potable water especially when used as coagulant in water purification processes.
The determination ranges of the iron analyzer vary from trace μg/L to 200 mg/L using the (optional) internal dilution module. Ranges also depend on the chemical method used.


This parameter has more than one analytical method. Choose one below.

In an acid buffered solution, ferrozine and iron react to form a purple colored complex measured at 572 nm. The absorption intensity is proportional to the iron concentration in the sample.

In a slightly acidic buffered solution, 1,10-phenanthroline and ferrous ion react to form an orange color in proportion to the iron concentration. The Fe(II)-phenanthroline complex is quite stable and measured at 430 nm. The absorption intensity is proportional to the iron concentration in the sample. A reduction of Iron(III) to Iron (II) must first be carried out in order to measure both iron species.


(Ø 26 mm)
3 ppm
(Ø 16 mm)
7 ppm
(with dilution)
200 ppm
Wavelength 430 nm
Number of reagents 2
Min. analysis time 8 minutes

Technical Specifications

Model CL
Sampling Mode Batch, with freely settable frequency.
Sample Pressure-free vessel
Temperature: 5 to 50 °C (41 - 122 °F)
Flow Rate: 80 to 500 mL/min
Connection: 6 mm (¼-in.)
Drain Pressure-free drain
Connection: 12 mm (½-in.)
Input Streams 2
Cabinet Material Epoxy-coated stainless steel AISI 304
Dimensions (H x W x D) 604 x 380 x 242 mm (23.6 x 14.8 x 9.4 in)
Weight 20 kg (44 lbs)
Power Supply Input Voltage:115 - 240 VAC 50/60 Hz or 24 VDC (optional)
Power consumption: max. 80 W
Output signals 2 x 4-20 mA analog outputs
Modbus RTU via RS485
Alarms 2 SPDT programmable voltage-free relays
Digital Input Remote start / stop
Temperature 5 - 45 °C (41 - 113 °F)
Relative Humidity 10 to 90 % (indoor use, outdoor installation only possible with protective cabinet or shelter not included)
Protection Grade IP54


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