BEPC Ⅱ注入器真空系统改造

注入器真空系统的改造由为各种微波功率源系统服务的真空系统和常规真空系统组成,根据实践工作中的着重点,详细介绍了注入器真空系统工作特点,并从原理及工艺上对各种新改造的子系统如电子枪真空系统、正电子源真空系统、速调管真空系统和常规真空系统给予说明,并简单介绍了BEPC Ⅱ注入器真空系统现在的工作状态.     

真空冷却技术及其在食品工业的研究和应用

本文对真空冷却原理和系统作了简要介绍,分析了真空冷却技术存在的优缺点.论述了国内外真空冷却技术的研究进展,举例介绍其在食品工业的应用情况,最后指出真空冷却技术今后的研究趋势.     

真空计量的现状及发展趋势

介绍了真空计量、真空计量标准、真空测量与校准技术、空间真空测量等方面的内容.基于真空计量的现状,提出了真空计量的发展趋势.     

31.5kV电力机车牵引断路器用真空灭弧室的研制

在电力机车牵引断路器中,真空灭弧室起着电气连通、分断的重要作用,真空灭弧室的可靠运行是电力机车安全运行的根本。本文介绍一种机械寿命高、电寿命长、绝缘水平高的31.5 kV真空灭弧室。首先介绍了31.5 kV真空灭弧室的工作原理并主要从真空灭弧室的机械寿命高、真空灭弧室的电寿命长和真空灭弧室绝缘水平高3个方面分析了其关键技术。最后介绍了31.5 kV真空灭弧室的关键生产工艺。     

日本真空技术的应用现况

介绍了适用于超高真空和极高真空应用的出气速率近年来在日本的研究情况。同时介绍了日本昭和真空公司在真空镀膜方面的新应用。     

中国真空获得设备的进展

扼要介绍了中国真空获得设备的发展情况。对低中真空获得设备、高真空获得设备、无油抽气手段等三方面的内容作了介绍与分析。     

真空冷冻干燥机真空系统特性的研究

本文阐述了真空冷冻干燥机真空系统的性能参数 ,介绍了能满足冻干要求的几种真空系统 ,对它们的特性进行了分析比较     

高真空多层绝热二氧化碳低温容器真空寿命与绝热性能分析

首先介绍了影响真空绝热低温容器真空寿命的影响因素和常用的吸气剂,然后针对高真空多层绝热二氧化碳低温容器,进行了真空寿命和绝热性能的分析研究。     

空间真空测量技术研究

针对国内外在空间真空测量方面的研究状况作了简要描述,对研制的2种空间真空规(转换器方向性真空规和束检测器方向性真空规)进行了介绍,并对空间真空测量技术的后续研究工作作了展望。     

真空冷冻干燥设备的真空测量

本文依据真空冷冻干燥设备中温度对真空测量的影响，介绍了真空规的选择及安装     

罗茨真空泵的最大允许压差和溢流阀压差

文章分析了影响提高罗茨真空泵最大允许压差因素，提出了解决方法。介绍了带溢流阀罗茨泵的特点和溢流阀压差的试验方法，明确提出应对带溢流阀罗茨泵考核溢流阀压差。     

Automatic control of gas pressure in a vacuum system

This paper describes the development of a microprocessor based system to be used for the automatic setting of the gas pressure within a vacuum chamber.The requirements of the system have been presented by five modes of operation which are easily set up by thumb wheel and on/off switches on a panel. The microprocessor system automatically balances the rates of the pumping system and gas inlet to set and maintain the requested gas pressure. The gas inlet needle valve is controlled by either an ac or de motor. The use of computer software allows the system to be readily adapted for use with the commonly used needle valves, pressure gauges and pumping systems. It allows for non linear transducers and mechanical wear and additional modes of operation may be easily added when required. The system is intended for use as a subsystem of a microprocessor controlled vacuum system for laboratory or industrial use.The technique has been illustrated by controlling the pressure over the range 1–20 torr in a conventionally pumped vacuum system.     

高真空阀门漏率和升压率的区别

本文通过高真空气动挡板阀的数据分析来说明漏率和升压率在高真空范围内二者之间的差异。     

冷冻干燥工艺程序自动化研究

对冷冻干燥过程中的传热传质进行分析,依据冻干塌陷原理,编制具有自适应性的逻辑公式,设置物料塌陷温度、真空仓压力和过热度等输入参数.在BSNFD05冻干机上进行测试,结果表明,在冷冻干燥过程中,按照PLC中的自适应逻辑,以高精量传感器采集的加热板温度、真空仓压力和冷阱（捕水器）过热度为控制量,通过三通调节阀、真空挡板阀和供液电子膨胀阀等执行机构,实现在冷冻干燥过程中按照逻辑判断、不断修正自动形成工艺程序,最终完成冷冻干燥.     

A combined numerical-experiment investigation on the failure of a pressure relief valve in coal liquefaction

In a direct coal liquefaction unit, pressure relief valves locate on the pipeline between the atmospheric and vacuum towers. Failures of the valve components occur frequently owing to the harsh operation conditions. A combined numerical-experiment investigation on the failures of valves is conducted in this paper. The variation of relative erosion rates of WC–Co coating with impact angles, the function of relative particle velocity, and the distribution of particle diameters are obtained from the high-temperature erosion experiments. Furthermore, the erosion mechanism of WC–Co coating under large impact angles is clarified. In the numerical simulation, the evaporation–condensation, particle motion, erosion, and the modified RNG k-ε turbulence models are used to analyze the phase transition and particle erosion in the valves. Results showed that: due to the high pressure drop and convergent–divergent structure of angle valve, the coal-oil slurry flashes as it enters into the valves. The evaporation of liquid oil produces a large amount of vapor oil, and results in a rapid increase in flow velocity. High concentration solid particles, driven by the high-speed stream, tend to erode the inner surface of valves. Severe erosion can be found in the spool of angle valve, downstream bushings at the angle valve and ball valve. The calculation results agree well with actual failure morphologies, verifies the accuracy of the present prediction method.     

Quality control of vacuum insulation panels: Methods of measuring gas pressure

Presented here are different methods of measuring gas pressure, suitable for vacuum insulation panels. They are essential for reliable quality control of these products. New methods for measuring gas pressure in vacuum panels enable fast and efficient quality control after production. The gas and water vapour transmission of high barrier films used as vacuum tight envelopes for the panels can now be determined within a reasonable time. The presented methods are also very valuable for the development of new vacuum insulation products.     

Digitaler Gasdosierer im Grobvakuumbereich

Digital gas dosing device for rough vacuum Vacuum gauges are calibrated by comparing the gauge under calibration with a reference gauge. Both gauges are mounted at a vacuum chamber. Different pressures are generated in sequence, and at each pressure the readings of both gauges are recorded. In the coarse vacuum range, the pressures are usually generated by successive injection of gas into the chamber via a manually operated dosing valve. This procedure requires some time and also fatigues the operator's hand. Therefore, a digital gas dosing device based on electromagnetic valves was developed, which allows a faster und more precise pressure generation than the analogue dosing valve and which is also friendly to the operators hand. Dosing device and its usage are described.     

Studies on the characteristics of a piezoelectric gas admission valve

This article describes the detailed and systematic study carried out on a PV-10, piezoelectric gas admission valve for its application both in a closed loop vacuum control system and in dynamic systems. It is concluded that in the closed loop vacuum control system an optimum dc voltage is required for obtaining a set pressure for minimum pressure fluctuations in the vacuum chamber.     

真空开关真空度在线检测系统的开发

真空开关内部气体压力是决定其电气性能的主要因素,灭弧室气体压力的劣化将降低真空开关耐受系统电压的能力.本文利用自行开发的电场探头研究了真空开关屏蔽罩电位的有效值与真空度之间的关系,得出了相应曲线.系统通过测量真空开关屏蔽罩的电位相对正常值的变化情况,并运用趋势检测方法和比较算法对检测数据进行综合分析,消除了由于电磁环境变化引入的误差.该方法由于综合考虑了真空开关屏蔽罩处电场的有效信息,诊断性能得到了较大的改善,为真空开关的在线检测提供了科学依据.     

基于声比拟的压力管路阀门内漏噪声数值预报研究

阀门内漏对压力管路系统安全运行具有很大危害。基于声比拟理论,使用Fluent软件分别进行稳态及非稳态计算,获得阀门内漏的流场和声场特性。研究了管内介质、工作压力、横向距离以及阀门泄漏度对阀门内漏噪声的影响。通过实验对数值模拟方法的正确性进行了验证。研究表明,阀门内漏流场旋涡与噪声直接相关。阀门内漏的声场信号为宽频随机信号,气阀内漏声场强度大于水阀,声压级随工作压力的增大而增大,并且随阀门泄漏度和阀后横向距离先增后减。研究结果可为阀门内漏的噪声预报以及阀门内漏检测提供借鉴。