Gases can be identified and analysed by their spectral ‘fingerprint’. The DEFOR photometer utilises gases’ optical characteristics within the ultraviolet spectral range and analyses up to three measured components simultaneously. There are no cross sensitivities in respect of CO2 or H2O. This too is one of the factors that makes it easier to obtain exact measurements in many applications. On gas turbines, in power stations, DeNOx plants and desulfurization units DEFOR monitors even very small threshold limits.
UV gas analyzer to provide measurement of nitrogen oxidesIn addition to measuring extremely small NO concentrations, DEFOR can be simultaneously used to identify NO2. For many emission measurements that means there is no longer any need to use a chemiluminescence detector (CLD) or an NO2 converter. The DEFOR photometer’s ‘intelligent’ software can output both separately measured concentrations as an NOx total. That reduces capital expenditure and operating costs. As the ideal complement for the monitoring of emission thresholds it is also possible to measure SO2 as a third component in small concentrations.
Additional capacitiesBesides measuring gases using UV light, the DEFOR photometer can also be used in conjunction with other SICK analysis modules – all integrated within one case. Using a paramagnetic O2 sensor and a thermal conductivity detector, for instance, oxygen and hydrogen can also be measured. That increases the possible uses considerably. The chemical and petrochemical industries benefit from this in particular. It is both possible to monitor individual components in production operations, for example chlorine in plastics production, and to identify sulfur components in sulfuric acid production or in natural gas.
Detecting and comparingThe DEFOR process photometer measures gas concentrations through absorption of UV rays. An electrodeless discharge lamp emits both NO-specific and other wide-band rays. Using interference and gas filters, optimum measurement and comparison wavelengths related to the gas component are then selected inside the thermostatic filter wheel unit. These rays are directed onwards to detectors via the analysis and reference cells. A quotient is formed per detector from the obtained signal levels and these are then compared with each other. This double quotient formation compensates not only for any proportional signal drifts, but also any symmetric drifts. The system also performs an electronic calculation of cross sensitivity. This method of measurement promises selectivity and sensitivity, with the process photometer remaining highly stable at the same time. The UV lamp’s special design is unique. In comparison to other UV sources currently in existence, the SICK engineers have succeeded in prolonging the service life of this lamp significantly.
Easy to use and maintainBy using the optional adjustment unit, operators no longer need to use test gases. Adjustment is performed using adjusting filters that are able to automatically swing into place. The innovative signal processing and highly stable detectors facilitate outstanding long-term stability. Any drifts and influencing effects are compensated for. Using leading edge electronics and software, it is easy to achieve remote monitoring via networks and integration into process control systems. Maintenance is also easy to perform, as the DEFOR photometer is constructed on a modular basis using individual assemblies. A logbook function with status reports also makes troubleshooting simple.
The DEFOR photometer is available as a 19“ slide-in unit and in a wall cabinet for use in tough conditions. The wall cabinet is specifically designed for use in the chemical industry. The electronics are separated by a gas-tight seal from the analysis section. The risk of damage to the electronics caused by any corrosive or aggressive gases that are being analysed is thus ruled out from the start. A separate case purging system can optionally be used for even more ‘cleanliness’.
For use in areas where there is a risk of explosion the DEFOR photometer can, of course, also be used with the protection class pressurized casing in ex-zone 1 and in ex-zone 2.
For decades, SICK has been one of the world’s most innovative companies in the sensor sector. The latest technological knowledge and processes are implemented in innovative products and system solutions. They position SICK as a technology and market leader in the customer segments of factory, logistics and process automation.
More than 50 innovations and control solutions are planned from February 2009 until February 2010. SICK will launch a new product each week as part of its “SICK Innovation Marathon 2009”. All innovations – from No. 1 to No. 52 – are more than just products: they solve tasks intelligently, efficiently and precisely. And create unbeatable customer advantages.