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火力发电厂调节阀门的带压堵漏技术

2010-04-07 13:09:12 阅读10 评论0 字号:

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火力发电厂调节阀门的带压堵漏技术:   1前言 发电厂调节阀门主要用于控制各种设备及其管路上流体介质的运行,调节阀门的泄漏常发生在填料、法兰密封及阀体上,调节阀门长时间泄漏可造成阀杆和法兰密封面的冲蚀,最终可使调节阀门报废,加上介质流体的损失,使电厂的消耗增加,成本上升,经济效益下降。如果介质流体有毒、易燃、易爆、腐蚀性等发生外泄漏,则容易发生中毒、火灾、爆炸等伤亡事故和加快厂房设备的腐蚀速度,缩短其使用寿命,严重时污染周边环境,破坏电力生产,损害人们的身体健康。泄漏的存在严重威胁着安全生产,使电厂的非计划停机事故增多。以下介绍一些调节阀门泄漏原因及堵漏方法以及对调节阀门的维修和维护方法,供参考。 2调节阀门外漏的形式及因素 2.1调节阀门填料的泄漏及原因 调节阀门在操作使用过程中,阀杆同填料之间存在着相对运动,它包括转动和轴向移动。随着开关次数的增加,相对运动的次数也随之增多,还有温度,压力和流体介质的特性等影响,调节阀门填料是最容易发生泄漏的部位。它是由于填料接触压力的逐渐减弱,填料自身的老化,失去了弹性等原因引起的。这时压力介质就会沿着填料与阀杆的接触间隙向外泄漏,长时间会把部分填料吹走和将阀杆冲刷出沟槽,从而使泄漏扩大化。 2.2法兰的泄漏 调节阀门的法兰密封主要是依靠连接螺栓的预紧力,通过垫片达到足够的密封比压,来阻止被密封压力流体介质的外泄。它泄漏的原因有很多方面,密封垫片的压紧力不足,结合面的粗糙度不符合要求,垫片变形和机械振动等都会引起密封垫片与法兰结合面密合不严而发生泄漏。另外螺栓变形或伸长,垫片老化,回弹力下降,龟裂等也会造成法兰面密封不严而发生泄漏。法兰泄漏还有不可忽视的人为因素,如密封垫片装偏,使局部密封比压不足紧力过度,超过了密封垫片的设计极限,以及法兰紧固过程中用力不均或两法兰中心线偏移,xxx紧现象等都容易发生泄漏。 2.3阀体的外漏和原因 阀体的外漏主要原因是由于调节阀门生产过程中铸造或锻造缺陷所引起的,比如砂眼,气孔、裂纹等,而流体介质的冲刷和气蚀也是造成阀体泄漏的常见因素。 3带压堵漏的原理及优点 3.1带压堵漏的原理 带压堵漏的原理就是以液态介质在动态条件下,固态密封材料的密封机理为基本依据。方法是在泄漏部位装设专用设备,利用密封部位和专用设备之间形成的腔室,采用专用的高压注胶工具将密封胶注入腔室,并充满整个腔室空间,使密封胶的挤压力与泄漏介质的压力相平衡,建立一个新的密封结构来堵塞泄漏孔隙各通道,阻塞介质的外泄。 3.2带压堵漏的优点 (1)不需要停机或对系统进行隔离。 (2)不需要对系统进行泄压。 (3)节省大量的能源和人力。 (4)大大减少了因设备隔离或停机而带来的电量损失。 (5)减少了社会经济损失。 4几种常见漏点的带压堵漏方法介绍 根据发电厂生产现场的具体情况,可以采用更换调节阀门,更换调节阀门填料,更换法兰垫片或焊补孔洞的方法xx一般泄漏。 但对于生产运行中的调节阀门,在无法隔离的情况下,则必须采取相应的技术手段xx泄漏,以保证机组安全生产的正常运行。 4.1电厂调节阀门填料室泄漏的带压堵漏处理 采用注剂式带压堵漏技术是目前比较安全可靠的一种技术手段,它采用特别夹具和液压注射工具,将密封剂注射到夹具与泄漏部位部分外表面所形成的密封空腔内,迅速地弥补各种复杂的泄漏缺陷。在注剂的压力大于泄漏介质压力的条件下,泄漏被强行止住,注剂自身在短时间内由塑性体转变为弹性体,形成一个有弹性的密封结构并能维持一定的工作密封比压,达到重新密封的目的。目前,国内外生产和使用的密封注剂大致分为两类:一类是热固化密封注剂,这类注剂只有达到一定温度才能由塑料体转变为弹性体,常温下则为固体;另一类是非热固化密封注剂,它适用于常温,低温及高温场合的动态密封作业要求,这类密封注剂多制成棒状固体或双组分的腻状材料,将其装在高压注枪后,在一定的压力下具有良好的注射工艺性及填充性,且不失去调节阀门开关功能。下面介绍两种常用方法: (1)对于调节阀门填料函的壁厚大于8mm左右时,在动态条件下采用注式带压堵漏xx缺陷时,可以直接在调节阀门的填料函壁面上开设注剂孔的方式作业,密封腔就是调节阀门的填料函自身,注入到调节阀门填料函内的密封注剂的作用与填料所起的作用相同。首先在调节阀门填料函外壁的适当位置用直径10.5mm或8.7mm的钻头开孔,孔不能钻透,大约留1--3mm左右,撤出钻头,用M12或M10的丝锥攻丝,攻丝结束后,把注剂专用旋塞阀拧上,并使之处于开的位置,用直径3mm的长杆钻头把余下的调节阀门填料函壁钻透,这时泄漏介质会沿着钻头排削去方向喷出,为了防止钻孔时高温,高压,有毒或腐蚀性强的介质喷出伤人,钻小孔前可采用一挡板,先在挡板上用钻头钻一个直径5mm的孔,使之能套过长钻头上,加上挡板钻余下的壁厚则不会有危险。钻透小孔后取出钻头,把注剂专用旋塞阀拧到关的位置,切断介质连接高压注剂枪进行注射密封注剂的操作。如果调节阀门填料函内介质压力低,也可以用直径3mm的长钻头直接钻透小孔,再进行密封注剂操作作业。 2003年6月,攀钢发电厂3#机电动主汽阀自密封格兰漏就是采用这种堵漏技术解决了该调节阀门的泄漏问题,避免了一次非停机不可,才能解决的事情。 (2)对于填料函壁较薄的调节阀门,可以采用辅助夹具进行动态密封作业。辅助夹具只是为了弥补调节阀门填料函壁厚的不足,相当于一个固定在调节阀门填料函外壁的特殊接头,用以连接高压注剂枪。夹具的机械加工方法难以得到理想的局部贴合面,在条件允许情况下,可以适当修理调节阀门填料函外壁,使之与辅助夹具更好地贴合。如果泄漏调节阀门的填料外壁形状复杂或修整条件不允许时,可在辅助夹具底部垫一块石棉橡胶板或橡胶板,拧紧夹具螺栓,使垫在下面的橡胶板能很好地堵塞贴合面缝隙。辅助夹具上应有一个与注剂旋塞阀相配的螺纹贴块,接下来同壁厚的填料函操作一致,整个密封作业完成后,不要立刻开关调节阀门,等密封注剂固化后,才可投入正常使用。 2002年11月中旬,攀钢发电厂高压加热器进水门的平衡阀法兰泄漏,由于该调节阀门的填料函壁较薄,就是采用制作辅助夹具进行动态密封作业,解决了调节阀门的泄漏问题。 4.2电厂调节阀门法兰泄漏的带压堵漏处理 4.2.1铜丝围堵法 它适用于两法兰间隙较小,间隙量均匀,泄漏介质压力低的带压堵漏,可以在拆下的螺栓上直接安放螺栓专用注剂接头,一般不少于两个。 安装注剂接头时应松开一个螺母,安装好注剂接头,迅速重新拧紧螺母,然后再安装另外的注剂接头,不能同时将所需接头螺母松开,以免造成垫片上的密封比压明显下降,泄漏量增加,甚至会出现泄漏介质将垫片吹走,导致无法弥补的后果。如果原来泄漏量较大,可用G形夹子来维持密封比压的均衡,安装完注剂螺栓后,用工具将直径或略小于泄漏法兰间隙的铜丝嵌入到法兰间隙中,同时将法兰的外缘冲出唇口,使铜丝固定后在法兰间隙内,这样就组成新的密封腔。然后可连接高压注剂枪进行动态密封作业,注剂方向应从泄漏点相反处依次进行,终点应在漏点附近。 2003年6月,攀钢发电厂#1机低压联通管垂直法兰面泄漏就是采用这种堵漏技术解决了联通管法兰面的泄漏问题,避免了一次停机事故的发生。 4.2.2钢带围堵法 当两法兰间隙稍大且不超过8mm,介质压力小于2.5MPa时,可采用钢带围堵法进行运态密封作业。它对两法兰同轴度有较高要求,对法兰间隙均匀程度要求不高。钢带一般选用1.5--3.0mm的厚度,宽度20--30mm即可,制作时可采用焊接或铆接,两接头下方需加设过渡垫片,根据法兰尺寸确定安装注剂接头的数量。安装钢带时,应将钢带位于两法兰的间隙上,把连接螺栓稍拧几扣,再把两个过渡垫片加入,全部包住法兰间隙,继续拧紧螺栓,最终形成完整的密封空腔,这时就可以进行动态密封作业。 4.2.3法兰的凸形夹具堵法 当泄漏法兰间隙大于8mm,介质压力大于2.5MPa时,从安全和可靠性考虑,应设计制作成加工尺寸xx,整体密封性能好,耐高压的法兰夹具,它动态密封作业的成功率较高,是一种广泛使用的密封技术。作业前应在做妇:的夹具上安装旋塞阀,并使旋塞阀处于开启状态,操作人员应站在上风口,若泄漏压力或流量很大,可用压缩空气把泄漏介质向一边吹扫,或在夹具上接上长杆,使操作人员避免和少接触泄漏介质。安装时,夹具的注剂孔应处于两法兰连接螺栓的中间,并保证泄漏处附近有注剂孔,不要使注剂孔对准螺栓,以免增加注剂进入的阻力。夹具螺栓拧紧后,夹具与法兰接触{zd0}间隙不应超过o.5mm,注剂应先从离泄漏点最远处开始注入,逐渐靠近泄漏,直至泄漏停止。此方法也可用于管道的带压堵漏。 这种堵漏方法在攀钢发电厂#1、#2、#3机组日常维护中普遍应用,是管阀检修专业必须掌握的一种堵漏方法。例如,2003年#1、#2机组给泵正暖回水疏水一、二次阀法兰的泄漏;2003年2月份,#2机辅汽到除氧器疏水70%电动隔离阀前法兰的泄漏;2003年3月份#1机高压加热器进口法兰泄漏等等。 4.3电厂调节阀门阀体泄漏的带压堵漏处理 阀体的泄漏处理可适用于管道的泄漏处理,有以下两种方法, 4.3.1粘接法 它是利用胶粘剂的特殊性能进行带压堵漏的一种方法。对于压力介质及泄漏量小的砂眼部位,可先把泄漏点周围打磨出金属光泽,然后用锥度销钉对准泄漏点,适当力度打入,使泄漏明显减少或暂时性封堵。利用胶粘剂固化速度快的特点,及时地将销钉周围涂满胶粘剂,成立一个新的固体密封结构,达到止漏的目的。对于介质压力高,泄漏量大的缺陷,可用顶压工具进行密封作业,操作时把顶压机构固定在调节阀门的一侧,高速顶压螺杆,使顶压螺杆的轴向正对泄漏点,旋转顶压螺杆,利用顶压螺杆端部的铆钉紧紧地压在泄漏部位上,迫使泄漏停止。 如果铆钉顶端比泄漏点面积小,可在铆钉下再垫上一块软金属片,泄漏停止后,及时清理泄漏点周围的金属表面,除去铁锈和油污,将配制好的胶粘剂涂抹在周围。待胶粘剂充分固化后,拆除顶压螺杆与铆钉的固定螺钉,取下顶压机构,为了保证其耐压效果,可在处理好的泄漏部位用玻璃布等加固。 4.3.2焊接法 a)在阀体的泄漏介质压力低,漏量小的情况下,可用一个内径比泄漏点大一倍以上的螺帽,让泄漏介质从螺帽内流出,把螺帽焊在阀体上,再配一个与螺帽相同规格的螺栓,在螺帽底部放置一块橡胶垫或石棉垫,将螺栓顶部绕上生胶带拧入螺帽内,达到阻止泄漏的目的。对于泄漏介质压力高,泄漏量大的阀体,可用引流焊接法。首先用一块铁板,中间开设一圆孔,把一个与圆孔相当口径的隔离阀焊接在铁板的圆孔上,打开隔离阀,把铁板中心孔对准泄漏点贴合在阀体,让泄漏介质经铁板中心孔与隔离阀流出。如果贴合面不好,可在贴合面放置橡胶或石棉垫,然后把铁板周围与阀体焊好,再关闭隔离阀就能达到重新密封的目的。 b)在阀体的泄漏介质高温高压,但是调节阀门有较大的外形尺寸、泄漏量不大的情况也可以用焊接的方法,首先直接把阀体上与漏点相关的缝隙都焊死(不焊漏点),然后用一段符合工况(工作温度、压力)的管子长度视现场环境而定(一般取200mm左右即可),其直径应该大于漏点,把一台与管子相适应的调节阀门焊接在管子一端,并全开调节阀门,然后把管子另一端取对准漏点焊接好后,关闭调节阀门即可止住泄漏. 4.4{wn}堵漏法 不管是调节阀门哪一部分泄漏如果以上方法操作都有困难时也可以采用“包裹法”:使用符合工况的板材(管材)制作一个能包裹调节阀门整体或者是有漏点的阀体的箱体,把它焊在调节阀门上使之能包裹住漏点,如果在焊接箱 体时有困难,可以在箱体上开孔留到{zh1}再运用方法焊接法中的b)方法:加排汽阀的方法就可以容易封口焊接了。此种焊接方法在攀钢发电厂#1机的主汽道疏水、#3机主汽道旁路二次门、1#、2#、3#机组的高压加热器的疏水系统中多次运用,都取得了满意的成功。这种堵漏方法在攀钢发电厂#1、#2、#3机组日常维护中用的最多效果{zh0}的一种方法,也是管阀检修专业必须掌握的一种堵漏方法。 5结论 在发电厂生产现场还有其它部件的带压堵漏,如果我们能够掌握一些基本堵漏知识,对于电厂的经济性提高有很大的帮助。仅我厂一台100MW的机组启停一次,直接经济损失就达30万元人民币以上。所以,我们能够成功对现场泄漏点进行带压堵漏,减少非计划停机次数,其中的效益是显著的。总之: (1)带压堵漏是属于一种应急抢修性质的工作。带压堵漏处理的漏点是一种临时处理措施,有一定的局限性和时效性。在有条件的情况下,还是要对泄漏部位进行彻底检修。xx现场的"跑、冒、滴、漏"现象,提高设备运行健康水平的根本方法是要靠计划检修的合理性和提高设备检修维护的工艺。 (2)带压堵漏的工作环境恶劣、作业时间长、劳动强度大,作业中不确定因素多、作业风险大。工作前的安全准备工作非常重要,作业前的风险分析一定要充分,安全措施的落实一定要到位。 (3)带压堵漏是一门专业性很强的技术,要求作业人员的现场应变能力、对机械专业知识掌握以及带压堵漏专用工具使用等都有很高的要求。由于对作业人员和专用设备有很高的要求,这项技术在火电厂的推广有一定的难度。目前现场的带压堵漏工作都是由一些专业公司来完成的。 (4)带压堵漏是一种新技术,它还有一个不断改进和完善的过程,它有自身的局限性和适用范围。带压堵漏并不能解决一切泄漏问题,现在还处在探索和完善阶段。

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Thermal power plant with a pressure regulating valve Sealing Technology: 1 Introduction Power regulator valve is mainly used for controlling various equipment and pipeline fluid medium run, adjust the valve leakage often occurred in the filling, sealing flange and the valve body to regulate the valve stem and a long time can cause leakage flange sealing surface erosion, regulating valve that will allow the retirement, coupled with the loss of fluid medium, so that power consumption increases, costs rise, economic decline. If the fluid medium toxic, flammable, explosive, corrosive, etc. outside the leak occurred, then prone to poisoning, fires, explosions and other casualties and accelerate the corrosion rate of plant equipment and shorten its life, serious pollution of the surrounding environment, destroying the power production and damage people's health. Serious threat to the leakage of production safety, to plant more unplanned downtime incidents. Here are some of regulating valve leakage and plugging methods and regulating valve repair and maintenance methods, for reference. 2, valve leakage in the form of regulation and the factors 2.1 Regulation and the reasons for the leakage of the valve packing Regulating valve used in the operation process, the valve stem with the relative motion exists between the filler, which includes rotation and axial movement. With the increase in the number switch, the number of relative motion also increase, and also temperature, pressure and flow characteristics of such media influence, regulate the valve packing is the most vulnerable parts of the leakage. It is due to the gradual weakening of the contact pressure packing, packing their own aging, loss of elasticity causes. Then the pressure medium will be along the gap filler out of contact with the valve stem leaks, blown away a long time that some of the filler and the stem erosion groove, so that leakage of magnification. 2.2 Flange leak Regulating valve flange connecting bolts mainly rely on the preload, to achieve adequate sealing gasket through specific pressure, the pressure to be sealed to prevent leakage of fluid medium. There are many reasons that it leaks, the sealing gasket compression force shortage, combined with surface roughness does not meet the requirements, gasket distortion and mechanical vibration will cause the Flange sealing gasket and seal loose and leak . Another bolt deformation or elongation, gasket aging, decreased resilience, etc. can also cause cracks and leaks Mifengbuyan flange. Flange leak there can not be ignored human factors, such as the sealing gasket mounted side, so that partial pressure of less than tight seal over power, over the sealing gasket design limits, and the uneven force during fastening flange or two law Lan centerline offset, causing the phenomenon of fake compact and so prone to leaks. 2.3 The body of the leak and cause Valve body regulating valve leakage mainly due to the production process caused by casting or forging defects, such as trachoma, pores, cracks, etc., and flushing the fluid and gas valve leak caused by corrosion is a common factor. 3 Pressure Seal of the principle and advantages Principle 3.1 Pressure Seal Pressure Seal of the principle that in liquid medium in dynamic conditions, the solid sealing material sealing mechanism as the fundamental basis. Is part of the installation of special equipment in the leak, sealing parts and special equipment used between the chambers formed by using a dedicated high-pressure injection plastic sealant into the tool cavity to fill the entire cavity space, so that the extrusion force sealant equilibrium with the pressure of media leaks, the establishment of a new structure to plug the leak sealing the channel pore, blocking the leakage of medium. 3.2 Pressure Seal of the advantages of (1) does not require system shutdown or isolation. (2) without the pressure relief system. (3) save a lot of energy and manpower. (4) significantly reduced the isolation due to equipment or loss of power brought down. (5) reduce economic losses. 4, several common leak point method introduced Pressure Seal Power plant site under the specific conditions of production, can be used to replace the valve adjustment, replace the valve packing adjustment, replacement flange gasket or weld up holes in a general way to eliminate leakage. But production of the regulation valve operation, the case can not be isolated, you must take the appropriate technical means to eliminate leakage, to ensure the safe production of the normal operation of unit. 4.1 Power conditioning valve packing room deal with the leakage of Pressure Seal By Injecting Pressure Seal technology is a relatively safe and reliable technological means, it is the use of special fixtures and hydraulic injection tool, the sealing agent injected into the fixture with the leak site formed part of the outer surface of seal cavity, quickly to compensate for the leakage of various complex defects. Injecting greater than the pressure in the leakage of medium pressure conditions, the leak was forcibly stopped injecting agent itself in a short time changed by the elastic plastic body to form a flexible seal structure and can maintain a certain ratio of the work of sealing pressure, to achieve the purpose of re-sealing. At present, the domestic production and use of injecting sealants can be divided into two categories: one is heat sealed curing agent injection, such injection agents can only reach a certain temperature is changed by the elastic plastic body, was solid at room temperature; other Sealing a class of non-thermal curing agent injection, it applies to room temperature, low temperature and high temperature dynamic seal occasions operational requirements, such injecting sealants made more solid or two-component rod-like materials tired, be packed in high pressure injection gun After some pressure in the injection process of good and filling, without loss of function of regulating valve switch. Here are two common methods: (1) For regulating valve stuffing around 8mm wall thickness is greater than when used in dynamic conditions with pressure injection for plugging the defects, can adjust the valve stuffing in the walls and opened the way hole injection agent operation, the sealed chamber is self-regulating valve stuffing, stuffing injected into the conditioning valve inside the sealed note the role of agents and the role of filling the same. First, the valve stuffing in the regulation of the appropriate position on the outer wall diameter of 10.5mm or 8.7mm drill holes, not drill through the hole, leaving about 1 - 3mm or so, the withdrawal of the bit, with the M12 or M10 the tap tap, tapping After the wire, the special agent injection plug screwed on, and make it in the open position, the pole 3mm diameter drill bit to adjust the valve stuffing the rest of the wall to drill through, then leaking medium will be cut along the drill row to the direction of emission, in order to prevent the drilling high temperature, high pressure, toxic or corrosive strength of the medium emitting wounding, a baffle can be used before drilling holes first drilled in the bezel with a drill hole with a diameter of 5mm, so long to set the bit, with the remaining wall thickness of baffle drilling is not in danger. Remove the drill bit to drill through the holes after, the injection dose-related special plug screwed into position, cut off high pressure media connection agent injection gun for injecting sealants operation. If the regulator valve stuffing box pressure is low within the medium can also be long 3mm diameter drill bit to drill through the holes directly, further injecting sealants processing operations. June 2003, Panzhihua Iron and Steel 3 # machine electric power plant main steam valve is leaking from the sealed Grand plugging using this technology to solve the regulator valve leakage problems and avoid a non-stop is not to resolve. (2) stuffing thin walls for the regulation valve, auxiliary fixture can be used for dynamic sealing operation. Auxiliary fixture is adjusted to compensate for valve stuffing box wall thickness less than, equivalent to a fixed wall in the regulation of the valve stuffing the special connector to connect high pressure agent gun. Fixture machining methods can not be an ideal fit local surface conditions permit, you can properly adjust the valve stuffing box wall repairs, so that the auxiliary fixture better fit. If the leak valves by filling the outer wall complex shape or finishing conditions were not right, it can clamp the bottom of the pad 1 in the secondary asbestos rubber sheet or rubber sheet, tighten the clamp bolt, so that the rubber pad in the following sheet can be a good fit plug surface cracks. There should be a secondary fixture plug match the thread Injecting explant, followed with the same thickness of the stuffing operation, the sealing operation is completed, do not immediately switch regulating valve, such as injecting sealants cured before into normal use. In mid-November 2002, Panzhihua Iron and Steel plant water heater pressure balancing valve flange gate leakage, as the regulator valve stuffing thin walls is used for dynamic sealing fixture aids work to solve the regulator valve leakage problem. 4.2 Power conditioning valve flange leakage Pressure Seal Treatment 4.2.1 wire containment method It is suitable for both small flange clearance, clearance of uniform, medium pressure and low leakage Pressure Seal, you can remove the bolts special bolts placed directly on Injecting joints, generally not less than two. Injecting joints should be loosened to install a nut, installed Notes agent connection, quickly re-tighten the nut, then install another injection agent connection, not also be required to release the connector nut, so as to avoid the sealing gasket on the ratio of pressure decreased, an increase of leakage, there may even be blown away the gasket leak media, leading to irreparable consequences. If a large amount of the original leak, G-shaped clip can be used to maintain the balance of specific pressure seal, installing bolts injection agent, the use of tools or slightly smaller than the diameter of flange leakage of copper wire embedded into the flange gap of the gap, while flange of the outer edge of the lip out, so copper wire inside a fixed space after the flange, thus forming a new seal cavity. Agent can then be connected to high pressure injection gun for dynamic sealing operations, note contrast agent leaks from the direction of Department in turn, near the end point should be omitted. June 2003, Panzhihua Iron and Steel LP Unicom Power Plant # 1 vertical flange pipe leakage is to use technology to solve this plugging the Unicom pipe flange leakage problems and avoid a shutdown accident. 4.2.2 steel containment method When the two flanges without gaps larger than 8mm, medium pressure is less than 2.5MPa, the method can be used to transport steel to contain state seal operation. It has two coaxial flanges higher requirements on the flange gap uniformity ask for much. Steel generally used in the 1.5 - 3.0mm thickness, width 20 - 30mm can produce can be used when welding or riveting, two additional transition joints below the required gaskets, installed under the flange size to determine the number of joint injection agent. Installation of steel, should strip in the gap between two flanges on the connecting bolts slightly twisted a few buttons, then added two transition gasket, all surround the flange gap, continue to tighten the bolt, the end to form a complete sealed cavity, then the dynamic sealing operation can be. 4.2.3 convex flange clamp block method When the leaking flange gap is larger than 8mm, medium pressure greater than 2.5MPa, the consideration of safety and reliability should be designed into the processing dimensional accuracy, the overall sealing performance, high pressure flange clamp, dynamic sealing operation is successful higher, is a widely used sealing technology. Work should be done before women: the fixture is installed plug, and to plug is turned, the operator should stand on the outlet, if the leakage of pressure or flow of large, medium available compressed air to leak to the side of the purge, or connect the fixture on the pole, the operator and avoid contact to avoid media leaks. Installation, the fixture hole injection agent should be in the middle of the two flange bolts, and to ensure leaks near the hole injection agent, do not let the bolt hole injection agent, so as not to increase the injection of agents into the resistance. Clamp bolt tightened, the clamp and flange contact with the largest gap should not exceed o.5mm, agents should first note the most distant point from the beginning into the leak, gradually close to the leak until the leak stops. This method can also be used for plugging the pipeline under pressure. This plugging method in Panzhihua Iron and Steel plant # 1, # 2, # 3, widely used in daily maintenance unit is pipe valve repair professional must master a plugging method. For example, in 2003 # 1, # 2 unit to return water drainage pump is warm first and second valve flange leakage; in February 2003, # 2 auxiliary steam to the deaerator 70% hydrophobic electric isolation valve flange before leakage; March 2003 # 1 high pressure heater flange leaks and so on imports. 4.3 Power conditioning valve body dealing with the leakage of Pressure Seal Valve leakage treatment applied to pipeline leak handling, the following two methods 4.3.1 Bonding It is the use of the special properties of adhesive with pressure as a method of plugging. Leakage of pressure medium and small parts of trachoma can leak around the first metallic luster polished, then taper pin point targeting leakage, appropriate efforts to break into, so that significantly reduce or temporarily block leakage. Using the characteristics of fast curing adhesive, in a timely manner will be plastered around the adhesive pin to set up a new solid sealed structure, to achieve the purpose of Stop-leak. For the medium pressure is high, large leakage defects of press tools can be used to seal operations, operation of press agencies to adjust the valve in the side of a fixed, high-speed compression screw top, so that the axial screw top pressure is on leak point pressure rotary screw top, screw top pressure using the rivet ends pressed tightly on the leak location, leak forced to stop. If the rivet to the top than the leak point size, can rivet a soft pad under the sheet metal and then the leakage stops, clean the spill point in time around the metal surface, remove rust and oil, will be better prepared Apply adhesive around. When fully cured adhesive to remove screws and rivets, top pressure screws, remove the top press agency, in order to ensure its pressure effects, the leaking part in dealing with a good glass cloth reinforcement. 4.3.2 Welding a) in the low-medium pressure valve leak, leak a small amount of cases, be used with a diameter of more than double the leak of the nut, so that leakage of media within the outflow from the nut, the nut welded to the body, matched with a bolt and nut the same size, placed in the bottom of a nut or asbestos rubber pad, the bolts at the top of tape around the screw into the nut on the students, the purpose to prevent leakage. Medium for high pressure leaks, leak volume of body, can be draining welding. First of all, a piece of iron in the middle to open a hole, put a considerable hole isolation valve diameter of the hole on the welded iron, open the isolation valve, the holes at the center of the iron fitting leak in the valve body, medium to leak through the center hole and the isolation valve iron out. If the fitting surface is not good, can be placed in the fitting surface of rubber or asbestos pad, and then soldering iron around with the body good, and then close the isolation valve can achieve the purpose of re-sealing. b) medium at high temperature and pressure valve leakage, but the regulator valve has a larger form factor, leakage is not the case can also be used welding methods, the first directly to the body associated with the leakage gaps are welded shut (not weld leakage), then a line condition (temperature, pressure) of the tube length as the actual circumstances (usually can get about 200mm) in diameter should be greater than the leak, to a phase with the tube regulating valve adapted welding one end of the tube and adjust valve fully open, and then take the other side of the tube leakage aligned welding is completed, close the regulator valve leak can be stopped. 4.4 Universal plugging method No matter which part of regulating valve leaks if the above method can also be used when all the difficulties "parcel method": Use consistent condition of the plate (tube) to produce a valve to regulate the whole package or a tainted point of valve body box, put it on welding in the regulator valve so that it can wrap the leak, if the welded box Body difficult when you can stay in the box on the final hole and then use methods of welding in the b) method: the method increases exhaust valve seal can be easily welded. Such welding machine # 1 Power Plant in Panzhihua main steam Road hydrophobic, # 3, Highway Road, the main steam machine second door, 1 #, 2 #, 3 # Unit of the high pressure heater drain system used in many have achieved satisfactory success. This plugging method in Panzhihua Iron and Steel plant # 1, # 2, # 3 unit daily maintenance using the most effective way the best, but also control valve repair professional must master a plugging method. 5 Conclusion Power production at the site there are other parts of the Pressure Seal, if we can have some basic knowledge of plugging for the power plant to improve the economy of a great help. I am only a 100MW plant in the unit commitment time, direct economic losses amounted to more than 300,000 yuan. Therefore, we can successfully carry out on-site leak with pressure sealing, reduce unplanned downtime, which benefits are significant. In short: (1) Pressure Seal is a kind of emergency repair work of this nature. Pressure Seal leakage treatment is a temporary measure to deal with certain limitations and effectiveness. In the case of a conditional, or to conduct a thorough inspection of the leak site. Elimination of the scene, "Run, run, drip, drain" phenomenon, to improve the basic health equipment operation is reasonable to rely on scheduled maintenance and equipment repair and maintenance to improve the process. (2) Pressure Seal of poor working conditions, work long hours, work intensity, job elements of uncertainty, operating risks. The safety of preparations before the work is very important to pre-operational risk analysis must be sufficient to implement safety measures must be in place. (3) Pressure Seal is a highly professional technical, operating staff on-site response required skills and mechanical knowledge in the specific tools and Pressure Seal use of a very high demand. Because of the operating personnel and special equipment has a high demand, the technology in thermal power plant to promote a certain degree of difficulty. Pressure Seal the current site are done by professional companies to complete. (4) Pressure Seal is a new technology, it has a process of continuous improvement and perfection, it has its own limitations and scope of application. Pressure Seal can not solve all the problems of leakage, is still in the exploration and satisfactory.


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