/ 179 The iCAL HBU heated bubbler unit is used to humidify air or test gases for execution of automated quality checks on the exhaust gas measurement systems. The gases are led through two heated water tanks. The water content is measured via a high precision chilled mirror hygrometer. The iCAL HBU supports the sample dryer verification as well as the CLD quench verification according to EPA 40 CFR part 1065. BENEFITS AT A GLANCE • High level of precision (< 0.4 % of the selected step) • Pressure-independent flow stability • Plug and play integration • Simple use and operation • Excellent long-term stability • Remote diagnosis down to valve and sensor level • Factory-calibrated and individually certified, NIST traceable EMISSION CALIBRATION DEVICES AVL iCAL The accuracy of exhaust measurement systems is highly dependent on the quality and precision of the calibration devices used. The AVL iCAL calibration devices guarantee excellent accuracy and reliability and minimize operating costs through fully automated routines. This substantially reduces the time required by the operator. The AVL iCAL calibration devices allow for manual or fully-automated verifications of analyzers (linearity and NOx converter check) and system leak checks (CFO test). MEASUREMENT PRINCIPLE UND APPLICATION The gas divider iCAL GDU is a highly accurate device for the calibration of gas analyzers. The underlying physical principle is based on the combination of calibrated, critical nozzles allowing for the accurate dilution of the test gases. The pressures of the calibration and dilution gases are controlled by means of a precise pressure controller with extraordinary long-term stability. The NOx converter tester iCAL NGU is used to check the efficiency of the NOx converter of CLD analyzers. The technology is based on the gas phase titration between NO and O3 and provides known concentrations of nitrogen dioxide (NO2). The ozone (O3) is generated by means of corona discharge in an atmosphere consisting of pure oxygen (O2). The iCAL CFO (critical flow orifice) propane injection tester is used to inject a precise quantity (e.g. of propane) into the CVS dilution system or into a SHED chamber. The injected quantity is compared to the mass measurement of the CVS dilution system or the SHED chamber. For improved accuracy, the iCAL CFO is temperature- stabilized at 50 °C. Most regulations require the regular implementation of this CFO test. The iCAL calibration devices allow manual or fully automatic verifications of analyzers (linearity, NOX converter check) and system leak checks (CFO test). These devices can be connected to the exhaust measurement system by plug & play and are visualized in the iGEM software.
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