H4-DH-15-A differently during operation heat expansion of th Helical gearboxes H4

Flender/Flender Gear Units/Helical gearboxes H4

ile hydrocarbons Applying the research results, laboratory prototype has been fabricated with which benzene, representing series of other hydrocarbons, can be measured Given the specificabsorption crosssections of hydrocarbons,the instrument based on the dynamic derivative spectrometry should also be combined with DC-detection (direct spectrometry) Moreover, special developments of some important components have been accomplished 2. Working steps Within the laboratory frame, basic principles to develop an analytical device were investigated This device is to be applied for process control of emissions of hydrocarbons to optimize processes and to reduce pollutant emissions 3. Results Based on former IPM works of measuring trace gases such as NO, NH3 and 5 with prism- derivative-spectrometer, grating-derivative-spectrometer was built up With this spectrometer, basic measurements with respect to noise of the detectorlpream lifier unit to the required resolu- tion as well as to modulation frequency and amplitude were pexormed The investigations were also conducted for benzene as representative hydrocarbon showing distinctive absorptionband structures in the UVspectrum An important result of the measurements was that dynamicderiva- tive spectrometer (DDS) with moderate requirements to spectral resolution (approx 1 nm) oper- ated at low modulation frequency (close to 6 Hz) with an absorption path of only 1 cm is suffi- cient to determine concentrations of benzene in the lower ppm-range Besides the measurement of direct absorption (DC-signal), the DDS laboratory prototype, which was develo ed consequently in the IPM, permitted the measurement of derivative signals of first and secon8orders (1 - and 2f signals) Wavelength scan and modulation were controlled by alvoscannerwith planar holographicgridattechedtoit Forthesamplinga heated cuvettewith {eatable hose feeding is used With this device and with acuvette length of only5,4cm detection