Development Of A Detection Device Of Dvebath Absorbance Based On Dual Wavelength Spectrophotometric

With the development of social economy, the transition from the manual experience to theautomatic production in printing and dyeing industry is an inevitable trend. In the dyeingprocess of automatic production, the parameters in dyebath such as temperature, pH value,concentration, liquid level detection are must be detected.It is not easy to monitor theseparameters in the actual production process. The temperature is currenly detected most often.Actually, the concentration of dye solution plays a key role for production in the dyeing andprinting process. Two reasons are explained for this: Firstly,the dyeing unlevelness is closelyrelated to the variation of dyebath concentration; Secondly,the compatibility of dyes can beunderstood through detection of dyebath concentration. Compared with the related foreignresearches in dyebath concentration detection, domestic research is insufficient, therefore it isnecessary to study and develop the method and device for detection of dyebath concentration interms of improving dyeing product quality or in narrowing the gap with foreign institutions.Many methods for the dyebath concentration detection are proposed, includingelectrochemical method and optical analysis method. Electrochemical method has complicatedsteps and the operation time is long. So it is not able to be upgraded for online dye solutionconcentration measurement. The method of optical analysis is the main method for measuringdyeing parameters, the essence of which is to determination of dyebath concentration based onthe fact that different materials have different absorption spectrometry. In detection of dyebathsolution concentration, a single wave length spectrophotometric for the determination ofabsorbance is used and then the dyebath concentration is calculated as the traditional methodbased on Lambert Bill theorem. However, this method is incapable for dyebath which containinterfering materials.On this basis, a dual wavelength spectrophotometric method for thedetermination of the absorbance difference of dyebath solution is put forward in this thesis. Italso uses Lambert-Bill law through model transform to determine the dyebath concentration.Itnot only eliminates the background interference and improves the accuracy of measurement,but also solve the concentration detection problem of many dyes having the same or similarspectral problem.Based on the dual wavelength spectrophotometric method principle, the designed deviceconsists of three parts: optical path structure, mechanical structure and the hardware and software parts about electronic. In the optical path design,the Czerny-Turner system is utilizedwhich has many advantages such as simple structure, being easy to debug and no stray light.The mechanical transmission is to be implemented by a turbine worm gear with transmissionratio up to120:1, which is driven by a stepping motor subdivision driver,making themonochromatic light with high accuracy resolution up to0.05nm theoretically. The ARM7kernel microprocessor LPC2210, which has strong anti-interference capability and goodextension ability, is chosed as the main processor of the signal circuit. This designed dyebathconcentration detection device is successfully implemented, and it can detect the dyebathabsorbance difference in actual experiments.where the relative detection errors are within5percent, showing the feasibility of the device. In the future, its next generations will transformthe absorbance differenceto the dye concentration based on an appopriate model.