大型空分设备冷箱内管道安装质量控制

冷箱内管道的安装质量是决定冷箱安装质量的关键因素,而管道的焊接质量、管架的清洁度、管架的安装质量这三方面因素决定了管道安装质量的好坏,结合空分设备冷箱配管质量控制,叙述从这三方面来控制冷箱内管道安装质量的具体措施。     

空分设备冷箱内管道安装及检修经验分析

空分设备冷箱内管道的安装和检修质量是空分设备长周期稳定运行的关键因素之一。从冷箱内管道安装作业的基本经验、避免应力集中的措施、支架安装以及检修前的准备工作、检修平台的制作、检修过程控制等方面,阐述提高冷箱内管道安装和检修质量的经验。     

大型空分设备冷箱内低温管道设计优化技术

大型空分设备冷箱内低温管道的优化设计和安装质量控制,是提高冷箱运行安全性的一个关键因素。文章系统地介绍了大型空分设备的管道设计优化技术和冷箱内管道的规范性设计,并阐述了管架、仪表管的设计理念,提出了保证富氧介质管道安全的设计方案。     

大型空分设备冷箱内管道泄漏的原因分析及预防措施

介绍了3起大型空分设备冷箱内管道泄漏的现象,从安装、设计和操作方面对管道泄漏原因进行了分析,认为安装质量不过关是冷箱内管道泄漏的主要原因,最后提出了在设备安装方面的预防措施。     

空分设备冷箱内压力管道设计技术发展现状及展望

随着空分设备向大型化发展,冷箱内压力管道的设计技术水平得到了很大的提高,其在保证空分设备安全、稳定运行方面的作用也越来越明显。介绍现阶段空分设备冷箱内压力管道的设计现状,展望了空分设备冷箱内压力管道的安装方式以及协同设计、冷箱标准化的设计模式。     

集装箱式中小型空分设备的设计研究

集装箱式中小型空分设备以其生产周期短、质量稳定、用户现场安装简单等优点,越来越受到空分用户的青睐。以福建岩兴4100 m3/h液体空分设备为例,对集装箱式空分设备容器的设计与布置、冷箱内管道设计和支吊架设计等进行了探讨和总结。     

10000m~3/h空分设备整装冷箱内管道设计

空分设备整装冷箱的设计需充分考虑运输条件、安装能力等因素,对冷箱内塔器、管道等设备单元的布置和设计提出了更高的要求。从冷箱内设备布置、管道布置、管架设计、应力分析和管道CE认证方面,介绍了土耳其10000 m~3/h空分设备整装冷箱内管道设计的主要技术特点。     

空分设备冷箱内管道的精细化设计

随着空分设备大型化发展,冷箱内低温管道的合理设计在保证空分设备安全运行方面的意义日益重大。结合多年的设计经验以及低温管道安装、检修和故障处理的经验,从总体布置、管道的整体均匀受力和安全措施、管架的合理应用、冷箱钢结构的安全等方面,阐述了对冷箱内低温管道采取的精细化设计;提出为了减小冷箱内低温管道的受损程度而应采取的改进操作。     

浅谈空分冷箱内支架安装

介绍了空分冷箱内设备支架、管道支架、阀门支架的安装要点和注意事项.     

空分设备冷箱内管道变形和防范措施

随着单套空分设备规模的不断增长,冷箱内管道变形对空分设备正常运行的影响问题也越来越突出。文章详细分析了空分设备冷箱内管道变形的原因,从空分设备的设计制造和操作方面,提出了相应的防范措施。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

可燃气体检测报警器测量结果的不确定度评定

本文详细介绍了可燃气体检测报警器示值误差测量结果的不确定度评定方法。     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。     

心电图机电压测量示值误差测量值的不确定度评定

本文介绍了心电图机电压测量示值误差测量值的不确定度评定与表示方法。     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.