在大型发电机组运行过程中,低压加热器的液位测量是否准确直接影响到机组运行的可靠性和机组效率。通过对单、双室平衡容器测量系统的原理进行分析,指出了单、双室平衡容器测量系统的不足,而导波雷达液位计测量则可以直接检测容器中的实际液位高度和变化量,从而避免了平衡容器测量液位时由于温度、压力变化以及取样管存在漏点或堵塞对液位测量造成的影响,使真实液位检测变得简单易行,解决了虚假水位的问题。

In the process of large generating units,liquid level measurement of low pressure heater is a direct impact on the accuracy of the reliability and the efficiency of unit operation.By analyzing the principle of bal-ance container measurement system,double room balance container,points out the deficiencies of measurement system,double room,and the guided wave radar level meter can directly detect the container in the actual liq-uid level and variation,thus avoiding the balance container liquid level measurement due to the influence of temperature,pressure and the sampling pipe leakage or blockage caused by presence of liquid level measure-ment,the real liquid level detection becomes simple,solves the problem of false water level.

双室平衡容器是由正压补偿管、水杯、漏斗等零件焊接而成。工作过程中,饱和蒸汽因为凝结而释放的热量同时对正压补偿管和负压管加热,并且平衡容器的外层保温减少了热量的损失,从而使正压补偿管内水的重度在任何工况下都近似等于汽包内水的重度;又由于正确的选用正压补偿管的高度,不论容器内压力如何变化,正压补偿管的压力与负压管的压力变化值均相等,因此双室平衡容器输出的差压不变,即低置水位指示的水位不变。一旦水位发生变化,则输出的差压也随之变化,所以低置水位指示可以实时显示容器内的水位。

With the progress of science and technology, the boiler drum level measurement of the types of more and more, but the prices are more expensive. General in the 5-8million yuan. While the equilibrium con-tainer and pressure transducer mix, price is in ten thousand yuan, more accurate measurement of liquid level, can completely meet the requirements of the operation of the boiler. Is currently the highest cost-effective prod-ucts. This paper expounds the working principle of double room balance container and Hollysys DCS program compensating method.

环模设备是指完成卫星等航天器热平衡热真空试验的地面环境模拟设备，通常包括容器、热沉、真空系统、液氮系统等多个分系统。根据相关标准要求，容器内真空度只有优于1.3×10-3 Pa 时才能开展环模试验。本文列举了几例环模容器真空度不满足要求的典型情况，从容器本体、热沉、真空系统设备、法兰等几个方面开展了泄漏分析，并提供了解决思路。

The environment simulation equipment refers to the facility which is used to conduct the thermal balancing and the vacuum test for the spacecraft . It generally consists of serveral subsystems such as chamber , heat sink , vacuum system , liquid nitrogen system, etc. According to the related standard, the environment test could be carried out only when the vacuum degree exceeds 1.3×10-3 Pa. This paper lists several typical situations that the vacuum degree does not meet the requirements in the environment simulation equipment and performs some leakage analysis to chamber, heat sink, facilities of vacuum system and flange.Several means are proposed to solve these problems.

对双金属管锥形模旋转挤压过程进行分析和数值模拟。建立了运动许可速度场，并用来评估内能以及在摩擦和速度断面上的损耗功。通过平衡旋转模容器与芯棒滚动摩擦而产生的力矩来确定容器中材料的捻线长度。通过引入所需的外能来平衡总功，并优化模具与外部材料之间的有关滑移参数，得到挤压力。结果表明，采用锥模旋转挤压可使挤压力减少20%。采用ABAQUS有限元程序模拟双金属管的旋转挤压过程。模拟结果与分析结果表现出很好的一致性。

Bimetal tube extrusion process through rotating conical dies was studied analytically and numerically. A kinematically admissible velocity field was developed to evaluate the internal power and the power dissipated on frictional and velocity discontinuity surfaces. By balancing the moment applied by the rotary die with the moments caused by the circumferential frictions in the container and on the mandrel, the twisting length of the material in the container was determined. By equating the total power with the required external power, the extrusion pressure was determined by optimizing with respect to the slippage parameter between the die and the outer material. It is shown that the extrusion pressure is decreased by about 20%by the die rotation. The bimetal tube extrusion process through rotating die was also simulated using the finite element code, ABAQUS. Analytical results were compared with the results given by the finite element method. These comparisons show a good agreement.

在简要回顾三峡库区白鹤梁水下题刻保护背景,以及开展保护所面临的技术难点后,介绍了"水晶宫"、高围堰、自然掩埋、隔流隧道、异地仿制、自然掩埋和"无压容器"等保护方案。其中,"无压容器"保护方案因最大限度地保留了白鹤梁题刻的历史信息,遵循了文物保护的基本理念,且具有结构简单、水压平衡、利于参观的优点,而成为最终的保护方案。实践证明,白鹤梁题刻原址水下保护工程既满足了三峡工程蓄水的需要,又最大限度地保留了水下文物的原始性、完整性、观赏性,成为世界范围内水下文物遗产保护的成功范例。

The background of protection of White Crane Ridge Inscription in Three Gorges Reservoir area is reviewed; the technical characteristics and difficulties of the protection works are analyzed. Various protection solutions are presented such as"Crystal Palace", high cofferdam, natural embedding, isolated tunnel, copying model at other place, and "non-pressure ves-sel". The "non-pressure vessel" solution has been adopted because it follows the basic principle of cultural relics protection that reserves the historical information of the inscription as much as possible, moreover, it possesses advantages of simple struc-ture, pressure balanced and convenient for visiting. The engineering practices show that the in-situ protection works not only satisfies the demand of reservoir impoundment, but also reserve original, integrity and ornamental features of the inscription, be-coming a successful example for worldwide underwater cultural relics protection.