电动释放阀的泄漏原因及处理方法

译文：
分析了进口102 —TAL MATIC 型电动释放阀泄漏的原因。通过相应的改进, 有效地解决了该阀泄漏问题, 确保了阀门的性能。 1 、前言 　　华能南通电厂的1 号和2 号锅炉是美国B&W公司制造的亚临界、一次中间再热、自然循环燃煤锅炉, 锅炉额定蒸发量为1085.1t/ h。 　　在锅炉的汽包、过热器出口及再热器进出口装有弹簧式安全阀。为了保证过热器安全阀的使用性能, 在主蒸汽出口管道上安装了国外制造的102 —TAL MATIC 型电动释放阀。该阀的额定动作压力为18.476MPa , 回座压力为17.897MPa , 排放量为119t/ h。该阀的起座压力和回座压力可自动与手动操作, 且排放量较小。因而在保护锅炉安全经济运行上有着重要的作用。但机组投产初期, 电动释放阀的泄漏发生较频繁, 影响了阀门的工作性能, 威胁着锅炉的安全运行。 　　2 、工作原理 　　电动释放阀由主阀、控制阀及控制装置3部分组成(图1) 。　　 　　蒸汽由主阀入口进入主阀体与阀腔衬套之间的间隙, 通过阀腔衬套上部的窗口进入阀腔, 其中一部分作用于阀瓣, 另一部分通过导汽管进入控制阀。 　 当控制阀处于关闭状态时, 蒸汽作用于阀瓣下面的作用力F1大于作用于阀瓣上方周边的作用力F2, 使主阀保持密封(图2) 。 　　当主蒸汽压力达到电动释放阀门动作值时,电接点压力表接通控制部分的电磁线圈电源。电磁线圈产生强磁场将铁芯向下推, 作用在杠杆上, 控制阀打开。同时作用在主阀瓣下面的蒸汽通过导汽管和控制阀进入大气, 失去对主阀向上推的作用力, 此时作用在主阀瓣上面的蒸汽将主阀瓣下推使主阀打开, 蒸汽对空排放。压力下降至17.897MPa 即电动释放阀回座压力时, 控制阀线圈失电, 铁芯上移, 控制阀杆受弹簧的作用力而上移, 控制阀回座, 主阀关闭。 　　3 、泄漏原因分析 　　3.1 控制阀 　　控制阀杠杆的调节螺钉与阀杆为点接触, 调节螺钉的中心距主阀中心小于控制阀杆中心与主阀中心距离约0.5mm (图3) 。由此看出, 两部件中心不在同一中心轴线上。主汽管道因蒸汽流速的变化会发生不同程度的震动, 从而引起杠杆上下运动, 带动调节螺钉撞击阀杆, 并使阀杆变形(控制阀的弹簧和蒸汽将控制阀杆向上推的作用力只能克服调节螺钉撞击的作用力, 不能克服阀杆变形的作用力) , 使密封面位移, 引起泄漏。 　　3.2 主阀垫片 　　主阀喷嘴与主阀座的接触面大于主阀座与垫片的接触面, 即喷嘴与阀座的摩擦力大于主阀座与垫片摩擦力。因此紧固压紧螺母时, 因摩擦力差异使主阀座随之而转, 使疏水管碰到阀体疏水管孔内壁, 造成阀座对垫片的作用力不足而引起主阀垫片处泄漏。 　　3.3 主阀密封面 　　由于系统中空气阀的通径小于疏放水阀通径, 当锅炉带压放水时, 系统将产生短时间负压, 将主阀瓣虹吸(缓冲弹簧不能克服) 下移, 使阀瓣上方排水管内的氧化物落下, 嵌入阀瓣与阀座密封面之间, 从而造成泄漏。 　　4 、改进 　　4.1 调节螺钉 　　将杠杆调节螺钉的球面改为平面, 即将2 球面的点与点接触改为平面与点的接触(图4) ,平面粗糙度Ra < 0.08μm , 螺钉材料选用2Cr13 , 经油淬火处理。这样既提高了调节螺钉平面的硬度与抗氧化性能, 又因其表面光滑减小了平面与阀杆球面作相对运动时的摩擦力, 确保了其动作性能。 　　4.2 装配工艺 　　重新组装阀门时, 不安装疏水管。在喷嘴、阀座及压紧螺母之间稍加粘度较小的润滑油, 通过主阀体疏水孔插入主阀座疏水孔中一根Φ6mm的铁棒,并按逆时针方向卡住,待压紧螺母紧固后, 将铁棒拿掉。这样可保证主阀的疏水畅通。 　　电动释放阀的零件采用研磨砂研磨, 其表面Ra < 0.08μm。控制阀杆与阀座密封面接触面应在其宽度的80 %以上。零部件应仔细清洗, 阀内不能有异物, 运行前不得将该阀打开。 　　4.3 操作方法 　　每当停运锅炉带压放水, 系统压力降至0.588～0.785MPa 时, 关闭电动释放阀的刹根阀及其旁通阀。 　　5 、结语 　　改进后, 电动释放阀的泄漏减少, 除正常的检修工作之外, 对该阀的检修维护工作每年只需要1～2 次, 为改进前工作量的1/ 6 , 确保了机组的安全经济运行 　

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原文：
Analysis of import 102-TAL MATIC electric relief valve leak. By corresponding improvements to effectively solve the valve leakage, ensure that the valve performance. 1 Introduction Huaneng Nantong Power Plant 1 and 2, the boiler is U.S. B & W manufactured sub-critical, an intermediate reheat, natural circulation boiler, boiler rated evaporation 1085.1t / h. In the boiler drum, superheater, export and re-heat the import and export with spring-loaded safety valve. Order to ensure the superheater safety valve performance, the main steamPLUG VALVES outlet pipe to install the foreign manufactured 102-TAL MATIC electric relief valve. The valve is rated action pressure 18.476MPa, back seat pressure 17.897MPa, emissions 119t / h. The valve from the seat pressure and reseating pressure automatic and manual operation, and emissions less. Thus in the protection of the boiler safe and economic operation on the important role. But the unit during the initial production, electric release valve leakage occurred more frequently, affecting valve performance, threatening the safety of boiler operation. 2 works Electric release valve from the main valve, control valves and control devices 3 components (Figure 1). Steam from the main valve entrance into the main body and the valve cavity lining the space between, through the valve cavity lining the top of the window into the valve chamber, a partMUD VALVES of acting on the valve flap, the other part through the steam conduit into the control valve. When the control valve is turned off, the steam acts on the valve flap following the force F1 is greater than acting on the valve flap at the top of the surrounding interaction F2, so that the main valve to maintain the seal (Figure 2). When the main steam pressure to power the release valve action value, the electric contact pressure gauge connected to control some of the electromagnetic coil power. Electromagnetic coil magnetic field will core down to push the role of the lever, the control valve is opened. Simultaneously in the main valve flap following the steam through the steam conduit and control valve into the atmosphere, loss of the main valve upward pushing force, this time acting on the main disc above the steam to the main valve flap push down to the main valve is opened, Steam air emissions. Pressure dropped to 17.897MPa the electric relief valve back seat pressure, control valve circuit is power, core Move, control valve stem by the spring force and the shift control valve seat, and the main valve closed. 3 Leakage 3.1 Control Valve Control valve lever adjusting screw and valve stem for the point contact, adjusting screw center distance of the main valve center less than control of the valve stem center and the main valve center distance of about 0.5mm (Figure 3). Thus seen, the two parts centers not on the same central axis. Main steam pipe for the steam flow rate change will occur in different degrees of shock, which led to lever up and down movement, led adjustment screw hit the stem, and to stem deformation (valve springs and steam to control the valve stem upward pushing force only overcome the adjustment screw collision forces can not overcome the stem deformation force), so that sealing surface displacement, causing leakage. 3.2 Main valve gasket Main valve nozzle and the main valve seat contact surface is larger than the main valve seat and gasket contactREDUCING VALVES surfaces, that is, the nozzle and the valve seat of friction is greater than the main valve seat and gasket friction. So tighten compression nut, because of friction difference to the main valve seat along the turn, so that drainage pipes run into body hydrophobic pores wall, causing the valve seat on the gasket force shortage caused by main valve gasket Department leakage. 3.3 The main valve sealing surface Because the system of air valve diameter less than the dewatering valve diameter, when the boiler with a pressure water distribution, the system will produce a short negative pressure, the main valve flap siphon (buffer spring can not overcome) down, causing the valve flap at the top of the drainage tube oxide down, embedded in the valve flap and valve seat sealing surface between, resulting in leakage. 4, improved 4.1 adjustment screw The lever adjustment screw sphere to a flat, about two spherical point and point contact to a flat and point of contact (Figure 4), plane roughness Ra <0.08μm, screw material selection 2Cr13, after oil quenching. This not only improves the adjustment screw surface hardness and oxidation resistance, but also because of its smooth surface and reduce the plane and stem sphere for the relative movement of friction, ensure that its action performance. 4.2 Assembly Process Re-assembling the valve, do not install the drainage pipe. In the nozzle, valve seat and the compression nut between the slightly low viscosity lubricating oil, through the main body weep holes into the main seat of hydrophobic hole in a Φ6mm an iron rod, according to counter-clockwise stuck, to be compression nut tightened, it will iron bar removed. This will ensure the main valve hydrophobic smooth. Electric release valve components used research frosted ground, the surface Ra <0.08μm. Control of stem and seat sealing surface contact area should be in its width more than 80%. Components should be carefully cleaned, the valve can not be a foreign body, before running not the valve is opened. 4.3 How When outage Boiler Pressure Drainage, system pressure down to 0.588 ~ 0.785MPa, close the electrical release valve screaming root valve and bypass valve. 5 Conclusion Improvements, electric release valve leakage reduction, in addition to normal maintenance work outside of the valve repair and maintenance work each year need only 1 or 2 times, to improve before the workload is 1 / 6, to ensure that the unit safe and economic operation