硅橡胶防污闪涂料涂覆工艺

电器设备涂覆硅橡胶防污闪涂料(RTV涂料)后能够大幅度提高污闪电压,本文在丙烯酸聚氨酯底漆上,采用不同的方法刷涂RTV防污闪涂料并研究其附着情况,发现底漆中-OH含量提高、干燥处理及加入偶联剂均有利于防污闪涂层的附着,而底材固化后放置时间的延长却不利于防污闪涂层的附着,并初步分析了原因.     

RTV硅橡胶防污闪涂层运行情况分析

综述了近几年国内室温硫化(RTV)硅橡胶防污闪涂层在电网中的运行情况,介绍了RTV硅橡胶防污闪涂层的憎水性,运行中RTV硅橡胶防污闪涂层失效的判断依据,以及失效后如何复涂等。针对四川省地理环境的特殊性,初步探讨了四川省RTV硅橡胶防污闪涂层的运行情况。     

RTV防污闪涂料性能的影响因素

介绍了室温硫化（RTV）硅橡胶防污闪涂料的作用机理。分析了RTV防污闪涂料性能的影响因素。提出了RTV防污闪涂料存在的问题及发展建议。     

涂料涂装技术快讯

新型防污闪PRTV复合绝缘子涂料10月15日,徐州供电公司为徐州电厂送出线路500千伏徐庄5207线涂上了用新型防污闪PRTV复合绝缘子涂料,大大提升了超高压线路的的防污闪水平。     

室温硫化硅橡胶的研究及其在防污闪涂料中的应用

概述了室温硫化硅橡胶(RrrV)用填料方面的研究进展,介绍了室温硫化硅橡胶在国内外电力系统防污闪领域中的应用,对目前RTV防污闪涂料在应用中所存在的问题及其解决方法提出了看法,展望r RTV防污闪涂料的应用前景.     

纳米氟碳涂层在防污闪领域的应用研究

介绍了一种新型纳米氟碳防污闪涂料。由于特殊的结构设计,涂层在憎水性、机械性能、防污闪性能、自清洁、融冰等诸方面皆有上佳表现。而目前使用较多的RTV涂料(室温硫化硅橡胶)综合性能一般,因此加大新型防污闪涂料的研究,可以继续促成防污闪工作的减轻和损失的减小。     

防污闪氟碳涂料的制备及应用研究

针对现有防污闪涂料寿命短、难复涂的问题,以FEVE氟碳树脂为成膜物,以纳米气相SiO2、微米聚四氟乙烯蜡粉、纳米金红石型TiO2等为填料,与钛酸酯偶联剂及其他功能助剂制备了一种新型防污闪氟碳涂料。按国家与电力行业相关标准对其进行了理化与电气性能检测、户外曝晒及带电运行试验。试验结果表明:新型防污闪氟碳涂料的耐候性、耐化学药品性、附着力、硬度等符合国家标准DL/T 627—2012要求,涂层水性接触角超过120°,体积电阻率、击穿场强、耐漏电起痕及电蚀损、相对介电常数与介电强度等电气性能满足防污闪要求;带电运行试验表明:涂覆防污闪氟碳涂料的绝缘子污秽严重程度可控制在E1内,运行中未出现刷状放电情况。试验表明:新型防污闪氟碳涂料性能优良,可以应用于高压绝缘子防污闪。     

基胶与填料对RTV硅橡胶防污闪涂层憎水迁移性的影响

采用模拟雾霾环境污染处理实验样品,研究了以α,ω-二羟基聚二甲基硅氧烷(107硅橡胶)为基胶的硅橡胶防污闪涂层的表干时间和憎水迁移性变化规律。研究发现,同时以高、低摩尔质量的107硅橡胶混合物为基胶的防污闪涂层的表干时间比单纯以其中一种107硅橡胶为基胶的防污闪涂层的表干时间短。调整高、低摩尔质量107硅橡胶的混合比例得到的防污闪涂层的憎水迁移性效果较好,相对于单一基胶配制的防污闪涂层更优。当摩尔质量为50 000 g/mol及4 000 g/mol的107硅橡胶的质量比为4∶1时,防污闪涂层的憎水迁移性最好。添加氧化铝可以增加防污闪涂层的憎水性和憎水迁移性,当氧化铝用量为10%时效果最好;白炭黑过多添加会影响防污闪涂层的憎水性和憎水迁移性,但在一定的范围内影响不大。白炭黑的用量为5%时防污闪涂层的憎水性以及憎水迁移性最好。     

输电线路用室温硫化硅橡胶防污闪涂料研究进展

室温硫化硅橡胶(RTV)以其独特的憎水性、憎水迁移性被用作新一代的防污闪涂料,给电力工业带来了巨大的经济和社会效应。大幅度提高RTV防污闪涂料的性能,达到国际先进水平,对电力系统确保无污闪事故发生具有极其重要的现实意义。本文综述了室温硫化硅橡胶的性能和应用,以及无机纳米微粒对室温硫化硅橡胶的增强研究进展。     

有机硅防污闪涂料的研制和应用

以线型聚硅氧烷为漆基,高绝缘材料为填料,聚四氟乙烯为助剂及复合型N－9固化剂配制成防污闪涂料,该涂料的防污闪性能优良,实际带电运行表明：在0．4mg/cm^2盐密、2．0mg/cm^2灰密下,污闪电压达到36．9kV。     

Experimental study of the influence of interior lining distributions on flashover in the enclosure with different ceiling structures

Different distributions of interior linings in an enclosure have been studied to reveal the influence on time to flashover. Two kinds of ceiling structures, flat ceiling and flat ceiling with beams, were used for enclosure. Six full‐scale experiments were performed to investigate the occurrence of flashover in large enclosures. Heat release rate, gas temperature, and surface temperature of the enclosure were measured and analyzed. Experimental results show that time to flashover is extended for enclosure with large surface areas and large doors. Whether lining the interior linings on the ceiling or beams has a significant effect on flashover. Considering that ceiling fires have effect on the progress of the spread of flame on the wall, time to flashover is reduced for the tests that are fitted with the interior linings on the wall of the enclosure. In the enclosure with beams, the direction of spread of flame on the ceiling is changed, resulting in the change of time to flashover. Additionally, the strength of ceiling jets that is affected by the heat release rate of fire source and the area of the interior linings mounted on the fire source influenced region affects flashover. It is observed that flashover occurs when flame fronts are throughout the upper part of the back wall and the flame‐covered area on the back wall exceeds 0.2 times the area of the back wall.     

Study on flashover in a single chamber lined with combustible materials

With the theories of fire dynamics and relevant parameters of combustible lining materials, a predicted model of hot gas layer temperature during pre‐flashover stage of enclosure fires was established, and the effects of lining materials on the likelihood of flashover were theoretically analyzed. By using common commercial lining materials, such as wall papers, foam plastics, wood‐based panels, and fabric‐upholstered wall panel, the phenomenon of flashover was reproduced in a small‐scale firebox of 1/4 sizes of ISO 9705 test chamber. By comparing the theoretical results with experimental data, the equation predicting the hot gas layer of quasi‐steady enclosure fires was gained; an indicator I_FO to reflect overall the hazards of flashover and to classify flashover fires was proposed, and its application was initially studied. The study results can be helpful to explain further and overall the effects of lining materials on enclosure fires and can be used to guide the prevention of flashover by choosing appropriate interior decoration materials. Copyright © 2012 John Wiley & Sons, Ltd.     

Studies of the combined effects of some important factors on the likelihood of flashover

Among those factors that affect the likelihood of flashover in enclosure fires, the thermal inertia of lining materials, ventilation factor of door openings, heat release rate of fuel, and internal dimensions of the enclosure are the most important. The effects of the four factors are related, so it is very necessary to study their combined effects. In the present study, based on analyzing the approximate heat balance on the control volume similar to that in the MQH method, a dimensional relationship was derived that facilitates the estimation of pre‐flashover temperatures, which is used in the popular guidance literature as the key parameters for practical methods of predicting flashover. By correlating a vast amount of data gained in both small‐scale and large‐scale enclosure fire experiments, an important equation was obtained, which can embody explicitly and quantitatively the combined effects of the four important factors on the likelihood of flashover. According to the temperature criteria of 600°C identifying flashover, a new ‘combined method of predicting flashover’ was put forward. The validity of the method was verified in small‐scale experiments, and the results showed that it could be applied to predict well whether flashover occurs in enclosure fires or not. Copyright © 2010 John Wiley & Sons, Ltd.     

Improved flashover performance and tracking resistance of silicone rubber by direct fluorination

Silicone rubber (SIR) samples are fluorinated using a F₂/N₂ mixture at different temperatures. Physicochemical characteristics are analyzed by attenuated total reflection infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Basic properties of the fluorinated surface layers are investigated, and the intrinsic alternating current (AC) flashover performance and tracking resistance of the surface fluorinated samples are evaluated. The flashover test results indicate that the fluorination leads to an improvement in AC flashover performance of the SIR material, as a result of the competition between the favorable effect of the increase in surface conduction and the adverse effect of a likely increase in surface layer permittivity. The increase in AC flashover voltage is associated with the voltage-increasing mode of the flashover test. The flashover test results also show an improved tracking resistance of the SIR material by the fluorination, and the improvement is especially significant for the fluorinated surface layer that has less cleavage of Si C bonds or a good compactness as well as a large thickness. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48556.     

New inspection criteria for flashover in compartmental fires

Whether flashover occurs in a compartmental fire can be confirmed by observing the phase space diagrams of fire temperature as commonly adopted in chaos studies. Two inspection criteria are proposed for determining flashover. Two full‐scale burning tests, one with and the other without flashover, are used to illustrate the inspection approach. Copyright © 1999 John Wiley & Sons, Ltd.     

A two‐step method for predicting time to flashover in room corner test fires using cone calorimeter data

A method to predict time to flashover in ISO 9705 room corner fire tests based on cone calorimeter data is proposed in this paper. The method involves classification of materials and estimation of time to flashover as two steps in sequence. In the first step, the investigated material is classified into discriminating material groups. In the second step, the time to flashover is calculated with a derived formula for the corresponding material group, which contains material density, time to ignition and heat release rate collected from small‐scale experiments. Compared with two existing models, the proposed method has improved the prediction precisions in both the time to flashover and classification of material categories for a wide range of materials. Copyright © 2012 John Wiley & Sons, Ltd.     

室内液化石油气轰燃特性的实验模拟研究

通过对中小规模的火灾实验箱进行实验,研究了通风口尺寸、泄漏速率等因素对轰燃特性的影响。结果表明,随着通风口宽度、高度、泄漏速率、通风因子的增加,轰燃越容易发生;在一定范围内,通风口开口面积越小、位置越靠近下部,发生轰燃的可能性越大;最后进行数值模拟,并与实验数据进行了对比。     

Hurst指数在判别火灾轰燃中的应用

为研究建筑火灾中温度的分形参数对轰燃判别的影响,利用火灾动力学模拟器对所构建的物理模型进行数值计算,在分析温度场和流场的基础上,根据分形理论基本原理,对该火灾模型温度变化过程所具有的非线性、突变性和分形降维特性进行分析与研究。运用分形理论R/S分析法,确定温度时序分形动力学参数的温度Hurst指数,并以室内某点温度为例,计算火灾轰燃发生时的 Hurst 指数。通过分析和评价温度Hurst指数与轰燃发生的关系,发现 Hurst 指数随着轰燃的发生出现降维突变规律,且降维时间与轰燃发生时间相吻合。这表明温度Hurst指数是评价火灾轰燃发生的一种有效的非线性分形动力学参数。     

基于不停电检测的RTV防污闪涂料运行状况的评估方法

对宁夏地区RTV(室温硫化硅橡胶)防污闪涂料运行现状进行了分析,提出一种RTV涂料运行状况的评估方法。该方法是在设备不停电检测的情况下,根据RTV涂料表面特有外观量进行模糊综合判定,通过计算得到RTV涂料防污闪性能的综合评价值,定量地对RTV涂料的运行状况进行了评估。分析结果表明:该方法简单、实用,不需要停电就可较为准确地评估RTV涂料的运行状况,确保运行中的RTV涂料具有良好的防污闪能力。     

Analysis of work on smoke component yields from room‐scale fire tests

Smoke Component Yields from Room‐Scale Fire Tests (NIST Technical Note TN 1453) has recently been published. This was expected to be an important work in developing concentrations and yields of toxicants that could be used for evaluating the usefulness of small scale smoke toxicity apparatuses (or fire models) for use in the prediction of the toxicity of materials and products in real fires. However, the work has a number of uncertainties that limit its potential for use as a reference. There are three major problems with this work. First, the post‐flashover concentrations of CO are too low (as recognized by the authors who recommend that this part of the data not be used). Second, the post‐flashover concentrations of the main toxicants measured (HCN and HC1) were much higher than found in most studies. Third, the precision of the data was inadequate. The consequence of the first two issues is that the work seriously overestimates the toxicological importance of gases known to have only minor effects in post‐flashover fires, such as HCN and HCl. The very low concentrations of toxicants measured at pre‐flashover conditions might have a value not discussed by the authors: an indication that pre‐flashover fires of the type conducted here do not generate extremely toxic atmospheres. Accordingly, the report does not provide reliable characteristic room scale combustion gas data that can be used for validating small‐scale furnaces. Copyright © 2005 John Wiley & Sons, Ltd.