Long-term stability is better than ever before and at the same time simple and inexpensive to buy and operate: SICK MAIHAK sets a new standard with its brand-new SIDOR infrared photometer. The completely redesigned instrument measures NO, CO, SO2 and O2 according to the latest requirements of the revised 13th BImSchV (German Pollution Control Directive) as well as CH4 and CO2. TÜV and MCERTS approval will be completed soon.

NDIR (non-dispersive infrared) photometers determine gas concentration by evaluating light wave and temperature changes in a gas-filled detector when it is exposed to infrared light. The principle of measurement has been proven in use for more than sixty years; NDIR instruments represent nearly half of all gas measuring instruments in production and combustion plants.
"System operators need reliable products with long operating times and low operating costs. When it comes to emission monitoring in line with the environmental laws, they are required to purchase analyzers and to monitor continually and, as far as possible, without interruption," according to Product Manager Dieter Deggim. Up until now, the disadvantage was that the highly sensitive detectors often needed re-adjustment Ð usually with test gases or with a built-in calibration cell. "For the operator this meant a lot of expense, to keep the test gases ready at hand and ready to be delivered to the analyzer and maintain a high level of security" explains the SICK MAIHAK Product Manager. With a calibration cuvette on the other hand, the analyzer was more expensive and the high cost of testing with gases (several times per day or as little as once per week depending on the manufacturer) led to high operating costs.
SICK MAIHAK however, decided to thoroughly simplify and improve the measuring technology. The main task: stabilisation of the measuring values. Dust, wear, temperature influences or unwanted reactions to the materials used continued to cause erroneous measuring values. The zero point and end point of the measuring range could 'drift'.
In countless test runs, the SICK MAIHAK Development Department led by Dr. Michael Zöchbauer, reduced and optimised the many different materials used in the instrument. A dual success story: "Our developers were not only able to eliminate foreign influences but were also able to significantly reduce the cost of materials" emphasised Dieter Deggim. The measuring values are now automatically standardised with new up-to-date signal processing. This enormously reduces the effect of interference. The newly designed chopper wheel unit allows the use of a second optical module with an additional source, so that two gases can be simultaneously and independently measured.
The result of the general redesign is a detector stability and simplification hitherto impossible. This allows low-maintenance operation of the photometer for many months Ð without the need for test gas. Even the built-in calibration cuvette is no longer required: the SIDOR only needs a single-point adjustment once a week, which can easily be carried out with inert gas or ambient air.
Even the instrument repairability was dramatically improved. The measuring cuvettes are now symmetrically constructed and snap into the correct position. No complicated alignment is necessary. In the same way, the exchange of all of the other components has been simplified. "As with our S 700 instruments, a factory-based temperature adjustment is not necessary after repair, unlike some of our competitors' products. All repairs can be done locally", another customer benefit, Dr. Zöchbauer points out. The compact 19" enclosure can house one or two measuring modules including an optional module for electrochemical or magnetic oxygen measurement. A sample gas pump or a flow or moisture sensor can be installed in the same housing. Connection to the system is simplified using a number of digital inputs and outputs.