浅析学生公寓卫生间渗漏原因及防治

通过分析学生公寓卫生间出现渗漏的原因,提出了相应的防治措施及处理方法。     

探讨屋面渗漏的原因与对策

屋面渗漏是建筑工程的质量通病,产生的原因很多,牵涉的范围广,分析原因,制定对策。通过从设计→施工→使用的综合防范治理,解决屋面渗漏的问题。     

小波变换用于钢丝绳断丝检测的研究

本文采用漏磁场探伤方法对钢丝绳断丝进行检测,该方法的原理是利用励磁磁场和缺陷(即钢丝断丝处)相互作用产生的漏磁场来检测钢丝绳断丝,并且利用霍尔元件能够准确地获取漏磁场信号.首次把声表面波式小波变换的重构器件应用于钢丝绳断丝检测中.发现声表面波器件的发射叉指换能器和接收叉指换能器的指条重叠包络均按照小波函数(如Morlet小波)包络设计时,从而得到声表面波器件的发射叉指换能器和接收叉指换能器的脉冲响应函数均等于小波函数,所以制作出了声表面波式小波变换的重构器件.该器件是一带通滤波器,其相对带宽是1.1%,所以该器件可有效滤除干扰信号.     

电子自动定时检漏吸枪的原理

针对当前检漏中吸枪和定时器的分离,并由此带来的操作不便等问题,提出了新型的电子自动定时吸枪,给出了该吸枪的电路原理。对其工作原理进行了简要说明。     

新型泵类产品密封性测试系统

介绍一种基于ＵＳＯＮ４０００的泵类产品密封性测试系统的组成、工作原理以及气源、夹具和控制台与ＵＳＯＮ４０００主机的接口设计。     

A vapour compression chiller fault detection technique based on adaptative algorithms. Application to on-line refrigerant leakage detection

The existence of faults in vapour compression chillers plays a significant role in terms of energy efficiency loss, performance degradations, and even environmental implications. In this paper, a dynamic model-based fault detection technique suitable for real-time implementation is proposed. The main objective is to obtain a reliable and automated tool for fault detection in vapour compression chillers, which can be applied in steady-state or transient operation. The fault detection methodology is based on comparing actual and expected performance using an adaptative model and operating variables dynamic thresholds. The technique has been successful applied for on-line refrigerant leakage detection with experimental tests involving the artificial introduction of the fault in a laboratory vapour compression plant, showing the results its capability of detecting incipient leakage failure conditions avoiding false alarms.     

承压设备泄漏检测方法综述

承压设备泄漏检测方法包括气泡检漏法、氦质谱检漏法、卤素检漏法、热导检漏法、压力变化检漏法、声波检漏法以及氨检漏法等。详细阐述了各种检测技术的原理、检测方法、相关设备、灵敏度及适用范围等。     

Leak rate calculation for LBB analysis in high temperature gas-cooled reactors

Leak rate calculation is very important for Leak Before Break (LBB) analysis. Helium is used as coolant in high temperature gas-cooled reactor (HTGR). Therefore the flows in the cracks of HTGR vessels and pipes are single phase, which are different from the two phase critical flows in the cracks of water reactors. In the present paper, simple leak rate calculation formulae for compressible laminar and turbulent flows in HTGR cracks are introduced. The velocity and pressure distributions in cracks as well as the leak rates are calculated using the formulae. Numerical simulations are also conducted for compressible laminar, turbulent and critical flows with different crack widths and depths. The results of the numerical simulation and theoretical formulae are compared with experimental data. The comparison shows that both the simple theoretical formulae and the numerical simulation can achieve good results.     

长输油气管道泄漏检测方法概述及实用性分析

随着我国国民经济的迅速发展,石油与天然气作为主要能源的代表,其需求量不断增大,长输油气管道的安全风险问题也备受关注。尤其是,近几年来管道泄漏爆燃事故时有发生,不仅给人民生命安全和财产造成了极大的损失,也给生态环境造成了污染和破坏。因此,将智能、高效的泄漏检测定位方法应用于油气管道及时制止次生灾害的发生显得至关重要。通过分析管道泄漏产生的主要原因,概述了目前常用的几种管道泄漏检测方法,并采用负压波和流量平衡法相结合的方法在原油管道进行泄漏检测实验。结果表明,该方法可以对输油管道泄漏进行实时监测,尤其是微小缓慢的泄漏,同时也可以准确定位泄漏点。     

A risk-based methodology for the optimal placement of hazardous gas detectors

Hazardous gas detection systems play an important role in preventing catastrophic gas-related accidents in process industries. Even though effective detection technology currently exists for hazardous gas releases and a majority of process installations have a large number of sensitive detectors in place, the actual operating performance of gas detection systems still does not meet the expected requirements. In this paper, a risk-based methodology is proposed to optimize the placement of hazardous gas detectors. The methodology includes three main steps, namely, the establishment of representative leak scenarios, computational fluid dynamics (CFD)-based gas dispersion modeling, and the establishment of an optimized solution. Based on the combination of gas leak probability and joint distribution probability of wind velocity and wind direction, a quantitative filtering approach is presented to select representative leak scenarios from all potential scenarios. The commercial code ANSYS-FLUENT is used to estimate the consequence of hazardous gas dispersions under various leak and environmental conditions. A stochastic mixed-integer linear programming formulation with the objective of minimizing the total leak risk across all representative leak scenarios is proposed, and the greedy dropping heuristic algorithm (GDHA) is used to solve the optimization model. Finally, a practical application of the methodology is performed to validate its effectiveness for the optimal design of a gas detector system in a high-sulfur natural gas purification plant in Chongqing, China. The results show that an appropriate number of gas detectors with optimal cost-effectiveness can be obtained, and the total leak risk across all potential scenarios can be substantially reduced. This methodology provides an effective approach to guide the optimal placement of point-type gas detection systems involved with either single or mixed gas releases.