Papers by Keyword: On-Line Measurement

Abstract: The short-circuit reactance is an important parameter to characterize the transformer ability to resist the attack of short-circuit current in the design the operation process. In this paper, the on-line measuring method for short-circuit reactance based on electrical parameters' characteristics was presented, and the feasibility to carry out on-line monitoring for the transformer operation condition was also analyzed. Besides, the principle of two on-line measuring methods based on respectively exciting current compensation and elimination technique was researched, and the calculation equations were deduced. The comparison between the on-line results measured from moving mold experiment and those from off-line short-circuit experiment showed that these two methods were accurate and valid.

Abstract: The quality of extrudate is closely related to its rheological properties during extrusion. Therefore, on-line measurement of rheological properties of polymer is important in extrusion process. In the present work, comparisons between the on-line viscosities of LDPE in single screw extruder and that in lab under the same condition were made by using online rheometer. Effects of set temperature of on-line rheometer, screw configuration and different positions, as well as weight proportions of filler, size of MICA particles of LDPE/MICA multiphase system on the melt viscosity in single screw extrusion are discussed.

Abstract: The online temperature detections of fiber along the spinning line should be the important means for the precise controlling of fiber higher order structures as well as fiber-final performance. In this paper, a method of measurement fiber temperature has been introduced which mainly use the instrument of monochromatic infrared thermometer to measure fiber temperature in the melt-spinning processes. Due to the probe field of view of monochromatic infrared thermometer being much larger than the fiber diameter, monochrome infrared thermometers can't be used to measure temperature of fibers directly, the measurement results is an average between the fiber and backgrounds, which can't be used to indicate the temperature of fibers directly and have to calibrated. The calibrated results of monochromatic infrared thermometer are compared to the measurement results of infrared thermography. It has been found that the on-line measurement with infrared thermometer could promise high-speed and highly reliable temperature testing for the fibers.

Abstract: After the technologies of measurement for thin-film thickness were analyzed, the method of real-time measurement for coating thickness based on quartz crystal oscillation was proposed. The principle of the thickness measured by frequency shifting was analyzed on theory, the functional relationship between the resonant frequency shifting and the film thickness changing was deduced. Aim at the complicated working condition in coating machine, the structure of the measuring system for reducing the influence from external pressure and temperature was designed. The circuit for detecting the frequency shift was designed. Final, according to the experiment result, the resolution of thickness measurement can achieve sub-micrometer level.

Abstract: On-line measurement of fiber temperature based on monochromatic infrared thermometer has been introduced. Due to the probe field of view of monochromatic infrared thermometer being much larger than the fiber diameter, the measurement results is an average between the fiber and backgrounds, which can't be used to indicate the temperature of fibers directly. In this paper, a temperature calibration method has been introduced to decompose the measurement result of monochromatic infrared thermometer, and the calibrated results are compared to the measurement results of infrared thermography. It has been found that the on-line measurement with infrared thermometer could promise high-speed and highly reliable temperature testing for the fibers.

Abstract: based on the analysis of the production technology and present status of online glass coating production, a non-contact measurement capacitance sensor, which is adaptive to the high temperature condition and enjoys a novel structure, is proposed in the paper. The online measurement of molten tin surface position in the CVD coating production process under the condition of 700°C can be realized with the sensor. The reliability and feasibility of the dynamic measuring system have been proved by the experiment. The dynamic accuracy is better than 0.1mm within the effective range of 25mm.

Abstract: A laser sensor based equipment was assembled for on-line measuring the fiber diameters during the polymer spinning. The analog signals come from laser sensor were detected by using a data acquisition instrument and transferred into digital ones, which were processed in time with Labview. In a typical experiment, the diameters of polypropylene fibers were tested under different spinning speed by means of that pre-calibrated on-line measurement equipment, and the testing results were compared with those obtained from the numerical simulation of spinning dynamics. It has been found the on-line diameter measurement could promise high-speed, highly reliable and flexible testing.

Abstract: According to the characteristics of grinding wheel wear in the grinding process, the grinding wheel wear forms and their reasons are analyzed. At the same time, as the grinding wheel wear will affect the size of components, the procedures of on-line measurement and compensation technology about grinding wheel wear are summarized. The current domestic and international research status of on-line measurement and compensation methods about grinding wheel wear are introduced, such as position calibration based method, machine vision based method, laser displacement based method, acoustic emission based method, grinding force based method, cutting vibration based method, grinding acceleration based method and pressure based method. Finally, the current research difficulties of grinding wheel wear’s on-line measurement and compensation technology are analyzed, and the further research direction is made.

Abstract: Cellulosic biofuels have been proposed to replace part of traditional liquid transportation fuels. Cellulosic biomass is the feedstock in cellulosic biofuel manufacturing. Costs associated with collection and transportation of cellulosic biomass account for more than 80 percent of the feedstock cost. By processing cellulosic biomass into pellets, density and handling efficiencies of cellulosic feedstock can be improved, resulting in reduction of transportation and handling costs. The pellet temperature is one of the most important parameter in Ultrasonic Vibration (UV-A) pelleting. There is very few literature on the pellet temperature of UV-A pelleting. This paper mainly studied how to on-line measure the pelleting temperature, also, the detailed temperature characteristics of the pellet was obtained. The results are valuable for selecting suitable pelleting parameters and controlling the quality of pellet in UV-A pelleting. Also, the accurate measurement of the pellet temperature is helpful to understand pelleting mechanism, charring, and durability issues.

Abstract: Fatigue crack propagation test is a very important testing way to study the metallic engineering material fatigue fracture characteristics by on-line measuring crack length under the cyclically varying loads. Crack length has been obtained through crack image capture, image processing and image analysis. In order to improve the crack measurement precision when the fatigue crack keeps growing, a new crack length real time measurement method based on the image processing and camera automatically tracking techniques was presented in this paper. This method includes the crack image processing algorithms and camera tracking and positioning movement control. The crack length measurement errors based on the camera tracking and fixed camera are respectively 0.076mm and 0.148mm.The experiment results show the proposed method has greatly improved the crack length measuring precision with the ordinary optical device.