A Prelimenery Investigation Of The Design Of Foreign Fiber Detection Device

In the course of detecting foreign fiber, it helps to improve the process and quality of the raw cotton by testing different fiber content and analyzing different fiber types. The cotton industry in China needs a foreign fiber detection system which has a superior performance and low price. This topic is a little attempt about usage of the high and new technology in cotton industry and preliminary exploration in this research about foreign fiber detection system.In this paper, this system in primary study is designed and built and the design about the lamp system, the feeding cotton system, removal system is explored. The main findings are as follows.(1) The foreign fiber device is designed and built and the images of the raw cotton by the usage of suitable light source and CCD camera.(2) In the selection course of the detecting lamp source, the suitable lamp is found by analyzing all kinds of lamp source and comparing with others. LED light source has no stroboscopic and low-intensity fluctuations by analysis of the advantages and disadvantages of various lamp sources. So it's necessary to determine the LED light source as the foreign fiber detection device. In order to detect the foreign fiber like the cotton fiber, the research found that polypropylene fibers and polyester fibers have differences with the cotton fiber in radiation whose ultraviolet wavelength is near 335 nm.(3) In this device's cotton pipeline, the program that is used the fan drawing out the air from the cotton pipeline within a certain negative pressure and is brought along the cotton fiber in low-speed flow of this pipeline is more feasible than the other two programs. So the air flow velocity in cotton pipeline in this program is very homogeneous and the fluctuation of velocity is relatively smaller by the numerical simulation of the air fluency in cotton pipe.(4) The air flow field in removal system is numerical simulated in foreign fiber detection device and some parameters on influences of air flow and turbulence intensity are discussed. The research finds the diameter of the nozzle and input pressure are important influence factors in cleaning the foreign fiber. It's beneficial for the removal system, because both the air axis velocity is increasing and the deflection angle of jet is falling with the outlet diameter increasing, but it also has the bad side that the turbulence intensity is increasing when the output aperture is too big. With the increasing size of the entrance section, the decrease in the axis direction flow velocity of the nozzle and turbulence intensity is beneficial to remove differences defibrillators. In addition, improving the nozzle inlet pressure can rise up the axis direction speed and decrease the deflection angle of jet, but the excessive pressure can cause the tubes inside turbulence intensity increased and not benefit to remove foreign fiber.