Diagnosis and analysis of common faults in X ray detector
Author： Shenzhen SHENFEI Electronic Technology Co., Ltd.Publish time：2018-06-30 17:07:32Views：571【SML】
Summary
X - ray security detector is widely used in airports, stations, conference centers, logistics industry, industrial testing and other places. The domestic suppliers are mainly American ...
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Summary
X - ray security detector is widely used in airports, stations, conference centers, logistics industry, industrial testing and other places. The domestic suppliers are mainly American L3, German Smith Hayman, Rui Yuan International, Italy Kai ya, the Ministry of public security, Tsinghua Tongfang, and so on. The security inspection instrument used by Limited by Share Ltd at Quanzhoujinjiang Airport The products of Hayman, Rui Yuan international and Ministry of public security are mainly products. This paper begins with the working state of the functional modules of the X - ray security detector, analyzes the common failures of the safety inspection instrument, so as to find out the cause of the failure as soon as possible, eliminate the fault, improve the efficiency of the equipment and reduce the adverse effects.
The working principle and function module of the radiographic security detector
The X ray security detector is sent to the X ray inspection channel by means of the conveying unit to complete the inspection. Its working principle is shown in Figure 1. It uses the characteristics of X ray, that is, penetrating, backscattering and fluorescence effects. After being scattered by the detected objects, the X ray energy of the detector is different from the different current signals. The image is generated by the image processing unit, and the image of the object is divided by the X rays displayed on the monitor. Identify the type of the object. Digital images can not only freeze images conveniently on the screen, but also do all kinds of image post-processing.
The inspected object enters the X ray inspection channel through the conveyor belt of the security detector, obstructs the detection beam from the optical barrier components on both sides of the channel, and causes the light barrier component to produce the signal. The signal is sent to the control part of the system to generate the X ray trigger signal and the X ray source to launch the X ray beam. A bundle of collimator X rays passing through the checked baggage on the conveyor belt was absorbed by the baggage and finally bombed on the X ray receiver. The receiver transforms the received X ray into a digital signal and sends it to the signal processing unit to form an image. Each part is shown in Figure 2.
Functional module of X ray security detector
There are belt conveyors, light barrier detectors, lead curtain and emergency switches.
Because the belt machine runs long and the belt is easy to run off, the belt edge is involved in the roller, so that the roller bearing is damaged and the work noise is produced. The noise of the work increases with the increase of the damage degree of the bearing. In the case of the logistics industry and so on, the failure probability of the roller bearing is increased.
Most of the belt conveyor rollers are closed lubrication, which may damage the oil seal when they are invaded by foreign objects, causing oil leakage from the drum and polluting the ground.
The motor of the belt conveyer provides power, and its components, such as motor drive capacitance, driving relay, protection switch, may fail, which causes the motor not to work and the belt pulley stops turning. The belt machine parts are shown in Figure 3.
The adjustment of optical barrier components / optical sensors is strict. If the optical barrier is disadjusted or required to be cleaned, the false trigger of the optical barrier may cause the computer to start the correction and make the X- rays connected. When the checked baggage passes through the inspection channel, the white screen, flower screen, black screen and towing bag appear. In particular, the inspection and safety inspection instrument, because of the heavy subject matter, the general belt machine is closer to the ground, and the possibility of affecting the optical barrier parts by the marking of the surface of the dust and the surface of the goods. A demonstration of the multipath optical barrier distribution is shown in Figure 4.
The lead curtain can prevent X ray radiation, and the regular security instrument has "radiation safety license" when it comes out of the factory, but in the process of use, X rays may still leak through the gap of lead curtain. Check the lead curtain at the entrance of the passageway to prevent the radiation from X - ray emission, and replace it in time.
The emergency switch can make the X ray security detector shut down immediately in the case of emergency. When the X ray cannot start, first check whether the emergency switch on the front or back or the operating table is pressed, then judge whether the external power supply is supplied, the operating table startup button or the protection switch is not working normally, the computer power part is part or not. If the work is normal and the circuit board fuse is burned or not, if it can not be judged, the failure unit should be analyzed according to the startup flow chart of the security instrument manual.
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