发电厂阀门的维修和维护
ValveRepair and Maintenance in Power Plants
火力发电厂阀门带压堵漏技术
Plugging Technology under Pressure in Thermal Power Plant
发电厂阀门主要用于控制各种设备及其管路上流体介质的运行，阀门的泄漏常发生在填料、法兰密封及阀体上，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。以下介绍一些阀门泄漏原因及堵漏方法以及对阀门的维修和维护方法，供参考
The valves in power plants are mainly used to control all kinds of equipments and the operation of the service fluid on the pipeline. The valve leakage usually occurs on the packings,flange seals and valve body, that the long-time leakage will damage the stem and flange sealing surface, which will finally damage the entire valve. And the loss of service fliud will increase the consumption and costs, which will decline economic benefits.If the service fluid contains any toxic, flammable, explosive, corrosive substances, the leakage will cause accidents such as poisoning, fires, explosions and speed up the corrosion against the equipments and shorten their life.For serious circumstances, it will pollute surrounding environment, damage power production and do harm to people's health.Leakage greatly threatens the production safety and cause more unplanned shutdowns of the power plants.Hereinafter are some causes of valve leakage and Plugging methods as well as valve repair and maintenance methods for reference.
2 阀门外漏的形式及因素
2 .Valve Leakage Types and Its Causes
2.1 阀门填料的泄漏及原因 Packing Leakage and Its Causes
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，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。
During the valve operation, there’re relative movements(rotation and axial movement) between the stem and packing. Along with the increasement of the number of opening/closing,the relative movements will increase accordingly, as well as other characteristics such as temperature,pressure and service fluid, the packing is the easist part to occur leakage.This is due to the gradually declined sealing contacting pressure, the aging of the packing, loss of elasticity and other causes. At this time, the pressurized service fluid will flow through the contacting gap between packing and stem and leak externally.And part of the packing will be blown away and the stem will be washed out of the groove, which will expanse the leakage.
2.2 法兰的泄漏Flange Leakage
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，造成假紧现象等都容易发生泄漏。 The flange sealing mainly relies on the tesion of bolted connections and achieve sufficient pressure ratio through gaskets, so as to protect the sealed pressurized service fluid from leaking. There might be many causes such as unsufficient tension of sealing gasket, the connection surface roughness is not in line with the requirements, gasket deformation and mechanical vibration and so on, all of which will make the sealing gasket not very compact with flange connection surface and lead to leakage.Besides, bolt deformation or elongation, the aging of gaskets, elasticity reduction, cracks will also make the sealing gasket not very compact with flange connection surface and lead to leakage. There’re also human factors for flange leakage that can not be ignored, for example,improper mounting of sealing gaskets will cause partial unsufficient pressure ratio and overdone tension, which excesses the design limit of the flange, as well as uneven force during flange mounting or the centerline of two flanges is offset, and flase fastening phenomenon, all of which will easy to cause leakage.
2.3 阀体的外漏和原因Body Leakage and Its Causes
阀体的外漏主要原因是由于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。
The main causes of body leakage is due to the casting and forging defects(such as sand inclusions, pores, cracks and so on) in the manufacturing process, and the erosion of the fluid medium and gas is also a common factor for body leakage.
3 带压堵漏的原理及优点
Principles of Plugging under Pressure and Its Advantages
3.1 带压堵漏的原理Principles of Plugging under Pressure
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。
Principle of plugging under pressure is based on the sealing mechanism of solid sealing materials under dynamic conditions of liquid medium. This is to say, to equip special equipments on the leakage parts,inject sealant into the chamber formed between the sealing parts and special equipments with a high sealant injection tool. After the chamber is fully filled with sealant, the squeeze pressure of sealant will be equivalent to the pressure of leaked media, which will form a new sealing structure, so as to plug the leaking gaps and protect the service fluid from leaking.
3.2 带压堵漏的优点Advantages of Plugging under Pressure
(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。
(1) No need to shutdown the units or isolate the system.
(2) No need to relief the system.
(3) Save a lot of energy and manpower.
(4) Greatly reduce the loss of electricity caused by equipment isolation and shutdown.
(5) Reduce the socio-economic loss.
发电厂阀门的维修和维护
ValveRepair and Maintenance in Power Plants
火力发电厂阀门带压堵漏技术
Plugging Technology under Pressure in Thermal Power Plant
发电厂阀门主要用于控制各种设备及其管路上流体介质的运行，阀门的泄漏常发生在填料、法兰密封及阀体上，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。以下介绍一些阀门泄漏原因及堵漏方法以及对阀门的维修和维护方法，供参考
The valves in power plants are mainly used to control all kinds of equipments and the operation of the service fluid on the pipeline. The valve leakage usually occurs on the packings,flange seals and valve body, that the long-time leakage will damage the stem and flange sealing surface, which will finally damage the entire valve. And the loss of service fliud will increase the consumption and costs, which will decline economic benefits.If the service fluid contains any toxic, flammable, explosive, corrosive substances, the leakage will cause accidents such as poisoning, fires, explosions and speed up the corrosion against the equipments and shorten their life.For serious circumstances, it will pollute surrounding environment, damage power production and do harm to people's health.Leakage greatly threatens the production safety and cause more unplanned shutdowns of the power plants.Hereinafter are some causes of valve leakage and Plugging methods as well as valve repair and maintenance methods for reference.
2 阀门外漏的形式及因素
2 .Valve Leakage Types and Its Causes
2.1 阀门填料的泄漏及原因 Packing Leakage and Its Causes
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，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。
During the valve operation, there’re relative movements(rotation and axial movement) between the stem and packing. Along with the increasement of the number of opening/closing,the relative movements will increase accordingly, as well as other characteristics such as temperature,pressure and service fluid, the packing is the easist part to occur leakage.This is due to the gradually declined sealing contacting pressure, the aging of the packing, loss of elasticity and other causes. At this time, the pressurized service fluid will flow through the contacting gap between packing and stem and leak externally.And part of the packing will be blown away and the stem will be washed out of the groove, which will expanse the leakage.
2.2 法兰的泄漏Flange Leakage
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，造成假紧现象等都容易发生泄漏。 The flange sealing mainly relies on the tesion of bolted connections and achieve sufficient pressure ratio through gaskets, so as to protect the sealed pressurized service fluid from leaking. There might be many causes such as unsufficient tension of sealing gasket, the connection surface roughness is not in line with the requirements, gasket deformation and mechanical vibration and so on, all of which will make the sealing gasket not very compact with flange connection surface and lead to leakage.Besides, bolt deformation or elongation, the aging of gaskets, elasticity reduction, cracks will also make the sealing gasket not very compact with flange connection surface and lead to leakage. There’re also human factors for flange leakage that can not be ignored, for example,improper mounting of sealing gaskets will cause partial unsufficient pressure ratio and overdone tension, which excesses the design limit of the flange, as well as uneven force during flange mounting or the centerline of two flanges is offset, and flase fastening phenomenon, all of which will easy to cause leakage.
2.3 阀体的外漏和原因Body Leakage and Its Causes
阀体的外漏主要原因是由于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。
The main causes of body leakage is due to the casting and forging defects(such as sand inclusions, pores, cracks and so on) in the manufacturing process, and the erosion of the fluid medium and gas is also a common factor for body leakage.
3 带压堵漏的原理及优点
Principles of Plugging under Pressure and Its Advantages
3.1 带压堵漏的原理Principles of Plugging under Pressure
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。
Principle of plugging under pressure is based on the sealing mechanism of solid sealing materials under dynamic conditions of liquid medium. This is to say, to equip special equipments on the leakage parts,inject sealant into the chamber formed between the sealing parts and special equipments with a high sealant injection tool. After the chamber is fully filled with sealant, the squeeze pressure of sealant will be equivalent to the pressure of leaked media, which will form a new sealing structure, so as to plug the leaking gaps and protect the service fluid from leaking.
3.2 带压堵漏的优点Advantages of Plugging under Pressure
(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。
(1) No need to shutdown the units or isolate the system.
(2) No need to relief the system.
(3) Save a lot of energy and manpower.
(4) Greatly reduce the loss of electricity caused by equipment isolation and shutdown.
(5) Reduce the socio-economic loss.