X射线实时成像技术在锅炉制造中的应用

1 前言 无损检测技术作为一种科学的无损检测方法,在锅炉压力容器的焊缝检测中,有极为广泛的应用。射线胶片照相检测是无损检测五大常规检测方法之一,X射线胶片照相方法具有检测结果直观、准确、底片存档可查等优点,但也不可避免地存在检测周期长、检测成本高等不足。尤其是锅炉蛇形管的检测,《安规》要求,76mm以下的管子对接焊缝的探伤比例至少50％,我公司每台锅炉的蛇形管的焊接接头非常多,一般在1000个左右,这样,探伤任务非常艰巨,管接头焊缝的射线探伤处于低效率、高消耗的状态中。另外,由于蛇形管的形状特殊性,在工艺上很难对焊缝做两次相互垂直的曝光,焊缝一次成像     

X射线数字成像检测技术在GIS设备上的应用

为将GIS设备故障消除在缺陷发展初期,必须要有一种"可视化"的无损检测手段帮助寻找缺陷,X射线检测技术正是苦苦寻求的良药。采用X射线数字成像检测技术,对GIS设备内部结构进行透射,并在成像板上得到设备内部结构影像,通过图像处理系统的分析处理,在GIS设备不解体的情况下得到了清晰的内部结构影像,实现了"可视化"无损检测的目的,为GIS设备的故障诊断及检修提供了技术支持。     

基于数字成像技术的自动压接设备故障可视化在线检测方法

为提高自动压接设备故障检测的准确性,提出基于数字成像技术的自动压接设备故障可视化在线检测方法.根据导线压接质量关键工艺参数分析,结合图像处理技术进行自动压接设备的自动标定尺寸分析,采用 X 射线数字成像技术,构建自动压接设备故障可视化在线检测的视觉特征分析模型.通过接续管压接后的无损特征监测,制定耐张线夹及接续管压接后无损检测的判别依据,通过图像视觉特征点标定技术,进行耐张线夹及接续管压接失效点定位.根据脉冲 X 射线数字成像的特征检测,实现对架空导线及自动压接设备的可视化检测和定位.测试结果表明,采用该方法进行自动压接设备定位的准确性较高,平均为 ９６．７％ .     

考虑线路电磁屏蔽的带电环境耐张线夹X射线检测方法

X 射线检测方法是当前普遍使用的带电环境耐张线夹检测方法,针对该方法使用过程中因传输距离较远,受到电磁干扰,造成检测精度下降的问题,提出考虑线路电磁屏蔽的带电环境耐张线夹 X 射线检测方法.启动 X 射线发生器、数字成像板与计算机终端等检测设备后,通过线路抗干扰与屏蔽体接地方式实现线路电磁屏蔽,利用计算机终端获取带电环境下耐张线夹 X 光片图像,采用专业图像处理技术对 X 光片图像实施处理,输出 X 光片图像与检测结果.电磁屏蔽过程中,线路抗干扰可通过电路滤波与信号滤波实现,屏蔽体接地采用并联单点接地形式实现.应用分析结果显示,该方法在高于和低于 ３３０kV 电压等级条件下的检测精度分别达到 ９２％ 和 ９５％ 以上.     

X射线探伤在压铸生产中的应用

阐述X射线探伤应用在压铸生产过程中,不仅为铸件的检测提供了高效、无损的检测手段,而且为技术人员提供了直观的内部缺陷分析,为模具的改进指出了明确的方向。实践证明,无损探伤在产品质量控制中起着重要的作用。     

冀家沟风机房1号主通风机超声波探伤检测研究

西铭矿冀家沟风机房1号主通风机根据煤矿安全生产的要求,每两年对主通风机主轴、叶柄、叶片和叶轮等关键部件进行探伤检测,保障主通风机的整机工作性能。主要针对主通风机叶柄的超声波无损探伤检测进行了实践研究。探测结果表明:该通风机26片叶柄扫查检测未见异常,X射线探伤仪探伤复查检测显示,叶柄及前三个铆钉部位未发生裂纹,评定结果为合格。超声波探伤检测可以有效地对通风机的叶柄的断裂及损伤情况进行有效的诊断。     

500kV开关断口间并联电容器高压介损问题分析

通过分析某500 kV开关断口间并联电容器的高压介损试验结果,说明了其在例行试验过程中,在10 kV检测电压条件下得出的数值超标主要是因为受到Garton效应的干扰,以至于检测数值比实际工作电压条件下的介损数值高,只有有效避免Garton效应的干扰,才能得到准确反映真实工作状态的结果,为状态诊断提供可靠评判根据.     

输电线路耐张线夹压接缺陷带电X射线无损检测方法

为提高输电线路耐张线夹压接缺陷检测的工作时效,提出了一种输电线路耐张线夹压接缺陷带电X射线无损检测方法。根据X射线无损检测技术原理对带电输电线路耐张线夹压接缺陷进行检测,获取缺陷检测图像,通过LVQ神经网络对缺陷图像边缘检测,通过划分图像像素点,获得目标边界图像,以此完成输电线路耐张线夹压接缺陷带电X射线无损检测。实验结果表明,此次研究方法不仅降低了缺陷检测误差,还缩短了缺陷检测时间,满足缺陷检测方法的设计需求。     

变电站10kV母线配合停电对配网调度运行的影响分析及对策

现阶段,社会对电力的需求和依赖度逐年提高,当输电线路或变电设备进行检修需要变电站10 kV母线停电配合时,为了避免发生因10 kV母线配合高电压等级设备检修造成配网用户长时间停电的情况,需要采用外电源10 kV线路串供变电站10 kV母线的操作使原本需要配合停电的10 kV母线继续保持运行状态。现对变电站10 kV母线配合停电对配网用户正常供电和变电站运行操作的影响进行分析,在此基础上提出了相应的解决措施。     

焊接试件X射线检测数字成像系统的研究与应用

多年来,为了提高培训质量,我中心探伤室每天都需要对大量学员的练习、考试试件进行X射线检查或工业电视检测。采用X射线片检测由于需要一系列的拍片、洗片、评片及存档登记等工作,因此周期长,探伤人员工作量大,洗片时还会产生大量的废液;采用工业电视进行检测,虽然省去了洗片工作,但是显示出的图像分辨率低、有畸变,只能定性地检测分析焊接缺陷。     

一种新型低功耗小型高压电源

介绍一种新型低功耗小型高压电源，该电源采用全集成化电路设计。由振荡电路产生脉冲方波推动开关电路，采用自举升压电路，提高高压变压器的初级电压。脉冲高压经高压变压器升压整流后，可得到需要的稳定直流高压，对于正高压，在高压升压电路后采用倍压整流，用直接取样反馈方式来凋整输出高压，使高压更趋稳定。该电源具有功耗低、体积小、重量轻、绝缘性能好等特点，而且输出高压连续可凋。电源的正负高压输出值分别为：正高压0～＋50kV、负高压0～-25kV。可用于小功率X光管供电和其他相关科学研究及野外作业。     

Longitudinally excited N(2) lasers without high-voltage switches

We have developed novel excitation circuits without high-voltage switches for two longitudinally excited N(2) lasers (wavelength: 337 nm). One uses a single tube without a trigger and the other uses a tandem tube with a trigger. In both systems, the discharge tube acts as a switch. In the single-tube system, the laser output energy was 125.8 microJ and the efficiency was 0.16% at 18 Torr (2.4 kPa) when a slow-rising voltage pulse of -28 kV was applied (rise time: 21.3 micros). In the tandem-tube system, the laser output energy was 259.4 microJ and the efficiency was 0.11% at 18 Torr when a slow-rising voltage pulse of -48 kV was applied (rise time: 27 micros).     

Operating features of a high-voltage spark gap switch with gas blow normal to the breakdown path in a repetitively pulsed mode

The results of studies of a high-voltage two-electrode spark gap switch (SGS) with forced gas blow at an operation voltage of up to 1.2 MV are presented. An SGS filled with nitrogen as the working gas at a pressure of up to 16 atm operated as the high-voltage switch of a high-current nanosecond electron accelerator. The gas flow was directed normally to the breakdown path. The SGS switched a 50-Ω forming line with an electrical length of 10 ns to a matched load. The voltage rise time across the electrodes before breakdown was ～25µs. A stable repetitively pulsed mode is realized at operating voltages of 100–680 kV and pulse repetition rates of up to 270 Hz with a standard deviation of the pulse breakdown voltage of ≤1%. The physical mechanisms that determine unstable operation of the device during self-breakdown are analyzed.     

Small switches of high-power microsecond pulses on the basis of high-voltage integrated pulse thyristors and reverse switch-on dynistors

A high-voltage switch on the basis of a small unit of series-connected high-voltage integrated pulse thyristors (HVIPTs), which were developed at the Ioffe Physical Technical Institute, was designed and investigated. At a power voltage of 25 kV, current pulses of microsecond duration with an amplitude of 2.8 kA and a rise time of 0.8 μs were switched. The attained current density through an HVIPT (5.6 kA/cm²) appreciably exceeds the permissible current density for conventional thyristors. It is shown that the developed HVIPT unit can be used in the triggering circuit of a high-power assembly of reverse switch-on dynistors (RSDs) at an operating voltage of 25 kV, which consists of 14 series-connected dynistors with a diameter of their structures of 24 mm. The RSD switch with a triggering circuit on the basis of HVIPTs allowed switching of rapidly rising current pulses with an amplitude of 20 kA and a duration of 150 μs. The small dimensions of the HVIPT unit (4 × 10 × 32 cm) and the RSD assembly (7 × 7 × 34 cm) determine the wide prospects for using them in high-power pulse technology.     

Development of high-voltage pulse-slicer unit with variable pulse duration for pulse radiolysis system

A high-voltage pulse-slicer unit with variable pulse duration has been developed and integrated with a 7 MeV linear electron accelerator (LINAC) for pulse radiolysis investigation. The pulse-slicer unit provides switching voltage from 1 kV to 10 kV with rise time better than 5 ns. Two MOSFET based 10 kV switches were configured in differential mode to get variable duration pulses. The high-voltage pulse has been applied to the deflecting plates of the LINAC for slicing of electron beam of 2 μs duration. The duration of the electron beam has been varied from 30 ns to 2 μs with the optimized pulse amplitude of 7 kV to get corresponding radiation doses from 6 Gy to 167 Gy.     

A high-voltage power supply based on a distributed capacitive energy storage

For the corpuscular plasma heating in the MST plasma device (Madison, United States), an injector of hydrogen atoms with 25-keV energy, equivalent at omic current of >45 A, and 20-ms pulse duration was designed and put into operation at the Budker Institute of Nuclear Physics (Novosibirsk, Russia) in 2009. The pulse repetition rate is 5 min. The output current of the ion source in the atomic injector exceeds 50 A. A high-voltage source with a 1.5-MW power was design ed for the high-voltage powering of the atomic injector. The run duration of the power supply with rated characteristics is >20 ms. The power supply is based on a distributed capacitive energy storage, which allows the power consumption from the industrial network to be reduced down to 10 kW at a pulsed load power of 1.5 MW. The high-voltage power supply smoothly regulates the output voltage from 0 to 30 kV and is capable of being quickly deenergized if high-voltage breakdown of the load takes place. The diagram and structural components of the high-voltage power system of the atomic injector are described, and its test results are given.     

A source of short X-ray pulses

A small-sized source of short X-ray pulses is described, whose basic components are a three-electrode X-ray tube operating at 30 kV and 0.5 A and a fast GaAs modulator connected coaxially to the tube grid. The limiting operating parameters of the source are a subnanosecond pulse duration and a pulse repetition rate as high as 100 kHz.     

Application of Triggered Vacuum Switches in a High-Voltage High-Speed Protective Device

The possibility of using triggered vacuum switches in a high-voltage high-speed protective shunting device that consists of several switches connected in series is considered. The probability of a breakdown in such a device at a uniform voltage division between switches was studied theoretically and experimentally. A circuit for controlling the protective device is proposed. The results of the development and tests of protective devices for 80 and 120 kV, based on two and three switches connected in series, are presented.     

High-power switches based on reversely switched-on dynistors for high-voltage pulse technologies

The results of comparative investigations of commercially produced reversely switched-on dynistors (RSDs) with an operating voltage of 2 kV and 76-mm-diameter structures are presented. The studies were performed in the mode of switching current pulses with an amplitude of 200 kA and a duration of 300 μs. The electric scheme of the power circuit of the generator of high-power high-voltage pulses with a switch on the basis of an assembly of RSDs is considered. RSD switches with an operating current of 250 kA and operating voltages of 12 and 24 kV are described. Some results of using RSD switches in high-voltage pulse technologies are presented.     

Control systems of high-voltage transistor switches

Control systems of high-voltage transistor switches are described. Possible ways to develop these systems are considered. A control system of the transistors of a high-voltage switch on the basis of a current loop is considered in detail. Signals for turning the transistors on and off arrive to their control boards from their common conductor with bipolar current pulses. A positive pulse turns the transistors on, while a negative pulse turns them off. The time interval between these pulses sets the time during which the switch is in the conducting state. The minimum duration of the conducting state is several microseconds, while the maximum duration is not limited. The results of tests of a switch prototype with an operating voltage of up to 4 kV are presented. The operation of the switch was demonstrated when obtaining rectangular pulses in the microsecond range across a resistive load. We also verified the possibility of forming pulses of damped oscillations at a frequency of 1 MHz by this device. The positive test results make it possible to develop switches for operating voltages of tens of kilovolts using the considered approach.