英语翻译There are many different types and manufacturers of auto

英语翻译There are many different types and manufacturers of auto-sort technologies on the market today,but they can be classified into three basic types.These technologies employ some type ofdetection signal that can differentiate plastic bottles based on chemical or physical characteristicswhen that signal is detected and analyzed by a sensor.The first type of auto-sortation is through optical sensoring.Optical sorting systems usevisible light to separate plastic bottles by color.The second type are systems based on“transmission technologies” whereby a signal passes directly through the bottle and isread by a sensor on the other side of the bottle.Each plastic resin has a characteristicresponse to the signal based on its unique chemical composition.The third type aresurface scanning devices where the signals bounce off the surface of the bottle and arereflected back to the sensor for identification.Similarly,each plastic resin type has itsown unique response.When a sensor detects what it is looking for,it will generallyactivate an air jet that will eject or direct the item it has positively identified.The majorsortation technologies in use today include optical,X-ray transmission (XRT),X-rayfluorescence (XRF),and near-infrared (NIR).Some auto-sort technologies are capable of multiple sorts,by both resin type and color,while some are known as “binary-sort” systems -- namely those that identify just oneitem and separate it from a stream of bottles.The first generation of auto-sorttechnologies were binary-sort systems primarily developed to provide reliable separationof two visually similar,yet highly incompatible plastics from a recycling perspective --namely PVC and PET.As has been discussed,PVC is a major contaminant in PETrecycling even at very low concentrations.The current state-of-the-art in auto-sort technology combines several types of sensors toprovide multiple sorting functions for streams of commingled plastic resin types.Forexample,one commercial system uses an XRT sensor to separate PVC bottles,then aninfrared sensor that separates bottles into clear,translucent and opaque categories,followed by optical sensors that sort bottles by color,and finally an NIR sensor toseparate the bottles by resin category.