原文：
         1、阀门漏泄 在设备正常工作压力下，阀瓣与阀座密封面处发生超过允许程度的渗漏，安全阀的泄漏不但会引起介质损失。另外，介质的不断泄漏还会使硬的密封材料遭到破坏，但是，常用的安全阀的密封面都是金属材料对金属材料，虽然力求做得光洁平整，但是要在介质带压情况下做到绝对不漏也是非常困难的。因此，对于工作介质是蒸汽的安全阀，在规定压力值下，如果在出口端肉眼看不见，也听不出有漏泄，就认为密封性能是合格的。一般造成阀门漏泄的原因主要有以下三种情况： 一种情况是，脏物杂质落到密封面上，将密封面垫住，造成阀芯与阀座间有间隙，从而阀门渗漏。消除这种故障的方法就是清除掉落到密封面上的脏物及杂质，一般在锅炉准备停炉大小修时，首先做安全门跑砣试验，如果发现漏泄停炉后都进行解体检修，如果是点炉后进行跑砣试验时发现安全门漏泄，估计是这种情况造成的，可在跑砣后冷却20分钟后再跑舵一次，对密封面进行冲刷。 另一种情况是密封面损伤。造成密封面损伤的主要原因有以下几点：一是密封面材质不良。例如，在3～9号炉主安全门由于多年的检修，疏水阀主安全门阀芯与阀座密封面普遍已经研得很低，使密封面的硬度也大大降低了，从而造成密封性能下降，消除这种现象最好的方法就是将原有密封面车削下去，然后按图纸要求重新堆焊加工，提高密封面的表面硬度。注意在加工过程中一定保证加工质量，如密封面出现裂纹、沙眼等缺陷一定要将其车削下去后重新加工。新加工的阀芯阀座一定要符合图纸要求。目前使用YST103通用钢焊条堆焊加工的阀芯密封面效果就比较好。二是检修质量差，阀芯阀座研磨的达不到质量标准要求，消除这种故障的方法是根据损伤程度采用研磨或车削后研磨的方法修复密封面。

 造成安全阀漏泄的另一个原因是由于装配不当或有关零件尺寸不合适。在装配过程中阀芯阀座未完全对正或结合面有透光现象，或者是阀芯阀座密封面过宽不利于密封。消除方法是检查阀芯周围配合间隙的大小及均匀性，保证阀芯顶尖孔与密封面同正度，检查各部间隙不允许抬起阀芯；根据图纸要求适当减小密封面的宽度实现有效密封。

    2、阀体结合面渗漏 指上下阀体间结合面处的渗漏现象，造成这种漏泄的主要原因有以下几个方面：一是结合面的螺栓紧力不够或紧偏，造成结合面密封不好。 消除方法是调整螺栓紧力，在紧螺栓时一定要按对角把紧的方式进行，最好是边紧边测量各处间隙，将螺栓紧到紧不动为止，并使结合面各处间隙一致。二是阀体结合面的齿形密封垫不符合标准。例如，齿形密封垫径向有轻微沟痕，平行度差，齿形过尖或过坡等缺陷都会造成密封失效。从而使阀体结合面渗漏。在检修时把好备件质量关，采用合乎标准的齿形密封垫就可以避免这种现象的发生。三是阀体结合面的平面度太差或被硬的杂质垫住造成密封失效。对由于阀体结合面的平面度太差而引起阀体结合面渗漏的，消除的方法是将阀门解体重新研磨结合面直至符合质量标准。由于杂质垫住而造成密封失效的，在阀门组装时认真清理结合面避免杂质落入。

     3、冲量安全阀动作后主安全阀不动作 这种现象通常被称为主安全门的拒动。主安全门拒动对运行中的锅炉来说危害是非常大的，是重大的设备隐患，严重影响设备的安全运行，一旦运行中的压力容器及管路中的介质压力超过额定值时，主安全门不动作，使设备超压运行极易造成设备损坏及重大事故。 在分析主安全门拒动的原因之前，首先分析一下主安全门的动作原理。如图1，当承压容器内的压力升至冲量安全阀的整压力时，冲量安全阀动作，介质从容器内通过管路冲向主安全阀活塞室内，在活塞室内将有一个微小的扩容降压，假如此时活塞室内的压强为P1，活塞节流面积为Shs，此时作用在活塞上的f1为： f1=P1×Shs……………………(1) 假如此时承压容器内的介质的压强为P2，阀芯的面积为Sfx，则此时介质对阀芯一个向上的作用力f2为： f2=P2×Shx..............(2) 通常安全阀的活塞直径较阀芯直径大，所以式(1)与式（2）中Shs＞SfxP1≈P2 假如将弹簧通过阀杆对阀芯向上的拉力设为f3及将运动部件与固定部件间摩擦力（主要是活塞与活塞室间的摩擦力）设为fm，则主安全门的动作的先决条件：只有作用在活塞上的作用力f1略大于作用在阀芯上使其向上的作用力f2及弹簧通过阀杆对阀芯向上的拉力f3及运动部件与固定部件间摩擦力（主要是活塞与活塞室间的摩擦力）fm之和时，即：f1＞f2+f3+fm时主安全门才能启动。 通过实践，主安全门拒动主要与以下三方面因素有关： 一是阀门运动部件有卡阻现象。这可能是由于装配不当，脏物及杂质混入或零件腐蚀；活塞室表面光洁度差，表面损伤，有沟痕硬点等缺陷造成的。这样就使运动部件与固定部件间摩擦力fm增大，在其他条件不变的情况下f1＜f2+f3+fm所以主安全门拒动。 例如，在2001年3号炉大修前过热主安全门跑砣试验时，发生了主安全门拒动。检修时解体检查发现，活塞室内有大量的锈垢及杂质，活塞在活塞室内无法运动，从而造成了主安全门拒动。检修时对活塞，胀圈及活塞室进行了除锈处理，对活塞室沟痕等缺陷进行了研磨，装配前将活塞室内壁均匀地涂上铅粉，并严格按次序对阀门进行组装。在锅炉水压试验时，对脉冲管进行冲洗，然后将主安全门与冲量安全阀连接，大修后点炉时再次进行安全阀跑砣试验一切正常。 二是主安全门活塞室漏气量大。当阀门活塞室漏气量大时，式（1)中的f1一项作用在活塞上的作用力偏小，

      在其他条件不变的情况下f1＜f2+f3+fm所以主安全门拒动。造成活塞室漏气量大的主要原因与阀门本身的气密性和活塞环不符合尺寸要求或活塞环磨损过大达不到密封要求有关系。 例如，3～9号炉主安全阀对活塞环的质量要求是活塞环的棱角应圆滑，自由状态开口间隙不大于14，组装后开口间隙△=1～1.25，活塞与活塞室间隙B=0.12～0.18，活塞环与活塞室间隙为S=0.08～0.12，活塞环与活塞室接触良好，平衡阀透光应不大于周长的1／6。对活塞室内要求是，活塞室内的沟槽深度不得超过0.08～0.1mm，其椭圆度不超过0．1mm，圆锥度不超过0.1mm，应光洁无擦伤，但解体检修时检查发现每台炉主安全门的活塞环、活塞及活塞室都不符合检修规程要求，目前一般活塞环与活塞室的间隙都在S≥0.20，且活塞室表面的缺陷更为严重，严重地影响了活塞室的汽密性，造成活塞室漏汽量偏大。 消除这种缺陷的方法是：对活塞室内表面进行处理，更换合格的活塞及活塞环，在有节流阀的冲量安全装置系统中关小节流阀开度，增大进入主安全门活塞室的进汽量，在条件允许的情况下也可以通过增加冲量安全阀的行程来增加进入主安全门活塞室内的进汽量方法推动主安全阀动作。 三是主安全阀与冲量安全阀的匹配不当，冲量安全阀的蒸汽流量太小。冲量安全阀的公称通径太小，致使流入主安全阀活塞室的蒸汽量不足，推动活塞向下运动的作用力f1不够，即f1＜f2+f3+fm致使主安全阀阀芯不动。这种现象多发生于主安全阀式冲量安全阀有一个更换时，由于考虑不周而造成的。 例如2002年5号炉大修时，将两台重锤式冲量安全阀换成两台哈尔滨阀门厂生产A49H-P54100VDg20脉冲式安全阀，此安全阀一般与A42H-P54100VDg125型弹簧式主安全匹配使用，将它与苏产Dg150×90×250型老式主安全阀配套使用，此种主安全阀与A29H-P54100VDg125型弹簧式主安全阀本比不仅公称通径要大而且气密性较差，在5号炉饱和安全阀定砣完毕，进行跑砣试验时造成主安全阀拒动。后来我们将冲量安全阀解体，将其导向套与阀芯配合部分的间隙扩大，以增加其通流面积，再次跑砣试验一次成功。所以说冲量安全阀与主安全阀匹配不当，公称通径较小也会引起主安全阀拒动。

     4、冲量安全阀回座后主安全阀延迟回座时间过长 发生这种故障的主要原因有以下两个方面： 一方面是，主安全阀活塞室的漏汽量大小，虽然冲量安全阀回座了，但存在管路中与活塞室中的蒸汽的压力仍很高，推动活塞向下的力仍很大，所以造成主安全阀回座迟缓，这种故障多发生于A42Y-P5413.7VDg100型安全阀上，因为这种型式的安全阀活塞室汽封性良好。消除这种故障的方法主要通过开大节流阀的开度和加大节流孔径加以解决，节流阀的开度开大与节流孔径的增加都使留在脉冲管内的蒸汽迅速排放掉，从而降低了活塞内的压力，使其作用在活塞上向下运动的推力迅速减小，阀芯在集汽联箱内蒸汽介质向上的推力和主安全阀自身弹簧向上的拉力作用下迅速回座。 另一方面原因就是主安全阀的运动部件与固定部件之间的磨擦力过大也会造成主安全阀回座迟缓，解决这种问题的方法就是将主安全阀运动部件与固定部件的配合间隙控制台标准范围内。

      5、安全阀的回座压力低 安全阀回座压力低对锅炉的经济运行有很大危害，旋塞阀回座压力过低将造成大量的介质超时排放，造成不必要的能量损失。这种故障多发生在200MW机组所使用的A49H型弹簧脉冲安全阀上，分析其原因主要是由以下几个因素造成的： 一是弹簧脉冲安全阀上蒸汽的排泄量大，这种形式的冲量安全阀在开启后，介质不断排出，推动主安全阀动作。 一方面是冲量安全阀前压力因主安全阀的介质排出量不够而继续升高，所以脉冲管内的蒸汽沿汽包或集气联箱继续流向冲量安全阀维持冲量安全阀动作。 另一方面由于此种型式的冲量安全阀介质流通是经由阀芯与导向套之间的间隙流向主安全阀活塞室的，介质冲出冲量安全阀的密封面，在其周围形成动能压力区，将阀芯抬高，于是达到冲量安全阀继续排放，蒸汽排放量越大，阀芯部位动能压力区的压强越大，作用在阀芯上的向上的推力就越大，冲量安全阀就越不容易回座，此时消除这种故障的方法就是将节流阀关小，使流出冲量安全阀的介质流量减少，降低动能压力区内的压力，从而使冲量安全阀回座。 造成回座压力低的第二因素是：阀芯与导向套的配合间隙不适当，配合间隙偏小，在冲量安全阀启座后，在此部位瞬间节流形成较高的动能压力区，将阀芯抬高，延迟回座时间，当容器内降到较低时，动能压力区的压力减小，冲量阀回座。 消除这种故障的方法是认真检查阀芯及导向套各部分尺寸，柱塞阀配合间隙过小时，减小阀瓣密封面直往式阀瓣阻汽帽直径或增加阀瓣与导向套之间径向间隙，来增加该部位的通流面积，使蒸汽流经时不至于过分节流，而使局部压力升高形成很高的动能压力区。 造成回座压力低的另一个原因就是各运动零件磨擦力大，有些部位有卡涩，解决方法就是认真检查各运动部件，严格按检修标准对各部件进行检修，将各部件的配合间隙调整至标准范围内，消除卡涩的可能性。

     6、安全阀的频跳 频跳指的是安全阀回座后，待压力稍一升高，安全阀又将开启，反复几次出现，这种现象称为安全阀的“频跳”。安全阀机械特性要求安全阀在整动作过程中达到规定的开启高度时，不允许出现卡阻、震颤和频跳现象。发生频跳现象对安全阀的密封极为不利，极易造成密封面的泄漏。分析原因主要与安全阀回座压力达高有关，回座压力较高时，容器内过剩的介质排放量较少，安全阀已经回座了，当运行人员调整不当，容器内压力又会很快升起来，所以又造成安全阀动作，像这种情况可通过开大节流阀的开度的方法予以消除。节流阀开大后，通往主安全阀活塞室内的汽源减少，呼吸阀推动活塞向下运动的力较小，主安全阀动作的机率较小，从而避免了主安全阀连续启动。

     7、安全阀的颤振 安全阀在排放过程中出现的抖动现象，称其为安全阀的颤振，颤振现象的发生极易造成金属的疲劳，使安全阀的机械性能下降，造成严重的设备隐患，发生颤振的原因主要有以下几个方面： 一方面是阀门的使用不当，选用阀门的排放能力太大（相对于必须排放量而言），消除的方法是应当使选用阀门的额定排量尽可能接近设备的必需排放量。 另一方面是由于进口管道的口径太小，小于阀门的进口通径，或进口管阻力太大，消除的方法是在阀门安装时，使进口管内径不小于阀门进口通径或者减少进口管道的阻力。排放管道阻力过大，造成排放时过大的北压也是造成阀门颤振的一个因素，可以通过降低排放管道的阻力加以解决。

“ Common causes of valve failure analysis and solutions ”是由中国安全阀网提供的国际阀门新闻，译文仅供参考。另外，中国安全阀网还提供相关产品搜索： 杠杆式安全阀、 微启式安全阀、 全启式安全阀、 封闭式安全阀、 高压安全阀等。

译文：
                 1, valve leakage  Under normal working pressure in the equipment, valves and valve seat sealing surface took place more than allowed levels of leakage, the valve leakage will not only cause loss of media. In addition, the media will continue to leak to the destruction of the hard seal material, but the common safety valve sealing surface is metal on metal materials, while striving to do is smooth, but in the medium to do with pressure situations to absolutely no leakage is very difficult. Therefore, the working medium is steam safety valve, the pressure value in the provision, if the invisible in the export side, it can not find leak, he said that sealing performance is qualified. Usually caused by valve leakage due mainly to the following three conditions: Case, the dirt fell sealing surface impurities will stay sealed mat surface, resulting in a gap between the spool and the valve seat to valve leakage. Eliminate this failure is to remove the dirt fall to the sealing surface and inclusion, the size of repair in the boiler ready to shutdown, the first security door run mound to do testing, if found to have conducted after the Shutdown of the disintegration of leak repair, if point after furnace test run mound safety gate leakage was found, presumably caused by this situation, can run 20 minutes before the cooling mound rudder run once, on the sealing surface to erosion. Another is that the sealing surface damage. Sealing surface damage caused by the following main reasons: First, seal surface material is bad. For example, in 3 main security door furnace No. 9 years of maintenance as the main security gate valve with the valve seat sealing surface generally has a very low research so that the hardness of the sealing surface also greatly reduced, resulting in sealing performance degradation, eliminate phenomenon is the best way to turning down the original sealing surface, and then re-welding process in accordance with drawing requirements and improve the surface hardness of the sealing surface. Note that the processing of certain quality assurance process, such as the sealing surface cracks, defects such as trachoma must go on to the turning re-processing. The new processing spool valve seat must meet the requirements of the drawings. Current YST103 common steel electrode welding process effects on the sealing surface of the spool better. Second, poor quality maintenance, valve seat grinding not up to quality standards, to eliminate this failure is based on degree of injury after the use of grinding or turning the sealing surface grinding method of repair.  Another cause valve leakage was due to improper assembly or the wrong size parts. Valve seat in the assembly processFORGED STEEL VALVES is not fully on or in conjunction with a translucent surface phenomenon, or is too wide spool seating is not conducive to sealing. Elimination method is to check with the space around the spool size and uniformity to ensure the valve sealing surface Far from the top hole and degree of inspection departments do not allow clearance up spool; according to drawings suitable reducing the width of the sealing surface to achieve effective sealing .  2, valve combined with surface leakage  Means the joint surface between the upper and lower body leakage Office, resulting in leakage of the main reasons that the following aspects: First, the bolt tightening force joint surface is not enough or tight side, causing a bad combination of surface seal. Elimination method is to adjust bolt tightening force, when we must act in the bolt on the angle of the tight manner, preferably tight side edges around gap measure, the bolt tight to bear the fixed date, and to integrate space throughout the area unanimously. Second, the joint surface of the tooth body gasket does not meet the standards. For example, a slight radial profile gasket grooves, parallel to the difference, too sharp or too sloping tooth defects such as will cause seal failure. Thus combining body surface leakage. When the good parts in the repair quality, use of standard tooth profile gasket can avoid the occurrence of this phenomenon. Third, the combination of surface flatness valve bad or hard of impurities caused by seal failure pad to live. As the body of the joint surface of the plane body caused by bad combination of surface leakage, remove the method is to re-grind the valve combined with the disintegration of surface until it meets quality standards. As a result of impurities stay sealed mat failure, carefully clean the valve assembly to avoid impurities falling into the joint surface. 3, impulse safety valve safety valve does not move Houzhu This phenomenon is often referred to as the main security door and refuse to move. Refuse the main security door in the boiler is running against a very large, a major equipment hidden, seriously affect the safe operation of equipment, once the operation of the pressure vessel and the line of medium pressure over rated, the main security gate no action, so that equipment can easily run over pressure caused equipment damage and major incidents. In the analysis of the main reasons for the security gate refused to move, first to analyze the main security gate of the action principle. Figure 1, when the pressure within the pressure vessel rose to the entire impulse pressure safety valve, safety valve impulse action, media rushed through the pipe from the container main valve piston room, the Pistons will have a tiny room expansion Buck, if this time the piston chamber pressure is P1, piston throttling area Shs, then the role of f1 in the piston is: f1 = P1 × Shs ... ... ... ... ... ... ... ... (1)    time pressure if the pressure medium within the container for the P2, spool area of Sfx, the media at this time, an upward force on the spool f2 is: f2 = P2 × Shx  ..............( 2) Usually the valve piston diameter than the large diameter spool, so equation (1) and type (2) Shs> Sfx  P1 ≈ P2 If the spring through the valve stem upward pull on the spool and will set f3 moving parts and friction between the fixed parts (mainly between the piston and piston chamber friction) is set to fm, the main security gate prerequisite for action: Only the force acting on the piston slightly larger role in the spool on f1 to f2 and the spring force upward through the stem upward pull on the spool moving parts and fixed f3 and the friction between components (mainly the piston and friction between the piston chamber) fm sum, that is: f1> f2 + f3 + fm to start when the main security gate.  Through practice, the main security gate and refused to move the following three main factors: First, there is jamming the valve phenomena of moving parts. This may be due to improper assembly, dirt and impurities mixed or parts Corrosion; piston chamber poor surface finish, surface damage, there are grooves and other defects caused by the hard points. This allows moving parts and fixed parts of the friction between the fm increased, other conditions remain unchanged in the case of f1 WATER POWER CONTROL VALVE more serious defects, which seriously affected the piston chamber of the steam confidentiality, resulting in leakage of steam piston chamber is too large. Eliminate this defect is: indoor surface treatment on the piston, piston and piston ring replacement qualified, the impulse in a throttle safety device system off a small throttle opening, increased access to the main security door into the piston chamber steam, in terms of permitting can also increase the impulse to increase the safety valve of the trip into the main security door into the piston chamber method to promote the main steam safety valve. Third, the main safety valve and safety valve of matching the impulse improper impulse steam flow valve is too small. Impulse valve of nominal diameter is too small, causing the piston chamber into the main steam safety valve insufficient to promote the downward movement of the piston force f1 is not enough, that is, f1 FILTER SERIES impulse valve sealing surface, the kinetic energy in the surrounding pressure zone, will raise the spool, so the impulse to continue to discharge safety valve, steam emission is, the kinetic energy pressure zone valve position the pressure the greater the role of the spool on the greater thrust upward, the less impulse valve easy back seat, this time to eliminate this failure is to be off the throttle, makes the media out of impulse flow reduction valve to reduce pressure on the kinetic energy pressure in the region, so that the impulse valve back seat. Cause back seat to the second factor is the low pressure: valve clearance with the guide sleeve with inappropriate, with the gap is smaller, the impulse valve seat Kai after instant savings in this formed part of the kinetic energy of a high pressure zone, will spool elevation, time delay back seat, when the container down to low, the kinetic energy pressure zone pressure decreases, the impulse valve back seat. Eliminate this failure is to carefully check all parts of the spool and the guide sleeve size, with the gap over an hour, reducing the valve sealing surface straight flap valve flap type waste gas cap or increase the diameter of the valve flap and the radial clearance between the guide sleeve to increase the flow area of the parts, so that the steam flows through so without too much throttle, Er Shi partial pressure increases the kinetic energy of the formation of a high pressure zone. Return Pressure caused by Another reason is the low-friction movement large parts, some parts are blocked, solution is to carefully check all moving parts, strictly follow the standard maintenance overhaul of various components, each component will be adjusted to meet the gap standards, to remove the possibility of jam.  6, the safety valve of the frequency hopping  Frequency hopping refers to the BALANCING VALVES safety valve back seat and after a slightly elevated pressure, in turn valve to open, repeated several times there, a phenomenon known as the safety valve of "frequency hopping." Mechanical properties required safety valve safety valve action in the whole process of opening up to the required height, does not allow for jamming, tremor and frequency of jumps. Frequency jumps on the valve seal is extremely negative, is very likely to leak sealing surface. Analysis of the major causes of back seat with the safety valve of high pressure up to the, back seat pressure is relatively high, medium container surplus emissions less valve seat has been returned, and when the operating personnel to adjust properly, pressure inside the container will quickly rise up,API CAST STEEL VALVES so the resulting safety valve, as this can open the throttle valve opening big way to be eliminated. The Open Throttle, the gateway to the main steam safety valve piston chamber source reduction, promote the piston downward movement to the smaller, less chance of the main safety valve, thus avoiding the main safety valve consecutive start.  7, a safety valve flutter  Safety valve in the discharge occurs during the jitter phenomenon, called a safety valve flutter, flutter phenomena caused by metal fatigue easily, so that the mechanical valve performance degradation, resulting in serious equipment hidden flutter occurred main reasons are the following: On the one hand is the improper use of the valve, the discharge capacity of selected valve too (as opposed to emissions), being eliminated is to use the valve should be rated as close as possible the equipment necessary for displacement of emissions. On the other hand is due to imports of small diameter pipes, less than the valve diameter of imports, or import control too much resistance, to eliminate the method is installed in the valve so the valve inlet tube diameter not less than the diameter of imports or reduce the resistance of pipeline imports. Discharge pipe resistance is too large, resulting in excessive emissions of the North when the pressure is caused by a factor of flutter valve, you can reduce the exhaust pipe of the resistance to be addressed.  

原文来源：http://www.1anquanfa.com/

2010-07-26 07:59

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