译文：
1、概述 内压自封式密封结构是高温高压阀门中法兰密封副经常选用的结构形式,某试验台架安装了两台相同的中法兰密封副为内压自封式密封结构的旋启式止回阀。在试验台架的多次交变工作压力和温度试验完成后,再次进行升压升温前常温试压过程中,其中一台旋启式止回阀中法兰的密封副发生泄漏,采取维修措施均没有解决此阀门的泄漏问题。而且另一台旋启式止回阀在试验台架上工作数年后,中法兰密封副也发生泄漏。为此通过对此阀门的泄漏问题的分析,阐述某些专用试验台架和工程选用的专用阀门产品的设计和设计参数的选择需认真商榷。 2、技术参数 两台旋启式止回阀出厂前曾进行了P=42.0MPa的整机阀门强度及中法兰密封副密封试验,无泄漏。 (1)试验台架 {zg}工作压力14.0MPa {zg}工作温度260℃ 设计压力17.2MPa 设计温度350℃ 工作介质水 试验回路管路通径65mm 试验台架试验压力21.5MPa 每次降至常压常温后再次升压升温前的试验压力15MPa (2)旋启式止回阀 公称压力28.0MPa(非标准公称压力等级) 公称口径65mm 阀体、阀盖材料1Cr18Ni10Ti 密封环材料N6 与试验台架回路连接方式焊接 3、故障 3.1、首次泄漏和修复 试验台架在进行数次常压升至{zd0}工作压力和交变压力、交变温度(按规定的升降温度和压力数率变化)升至{zg}工作压力、温度运行和试验后,降至常温常压保养。再次进行升压升温前常温试压(P=9.8MPa)过程时,试验台架上的一台旋启式止回阀在中法兰密封副处发生微量外泄漏(以下称首次泄漏)。拆解阀盖、密封环检查泄漏部位,密封环外圆密封面和阀体中法兰密封面有介质泄漏后留下的轻微痕迹。密封环外圆密封面的介质泄漏痕迹为外圆密封面锐角处有轴向长×宽约3×115mm的毛虫状痕迹,其痕迹贯穿密封面,用放大镜观察疑似材料的内部缺陷。在阀体中法兰密封面上有一处介质泄漏的轻微痕迹为水印,与密封环外密封面毛虫状痕迹相对应。具体部位在垂直阀体通道轴线方向(以下称横轴线方向)的中法兰密封面的一端,阀体中法兰密封面其他部位、密封环外密封面其他部位、密封环内密封面和封头密封面未见泄漏痕迹,各密封面处密封压痕均匀。 在拆解检修该旋启式止回阀中法兰密封副时,对此阀门中法兰密封面和密封环外圆密封面直径尺寸进行了测量。 中法兰密封面和密封环外密封面在两个垂直方向出现直径不一致即长短轴现象,长轴在阀体横轴线方向,短轴在沿阀体通道轴线方向(以下称轴线方向)。阀体中法兰密封面长短轴相差D2-D1=0.10mm,密封环外密封面长短轴相差d2-d1=0.04mm。阀体中法兰密封面短轴与垂直密封环泄漏痕迹对应处尺寸差D1-d1=0.02mm,阀体中法兰密封面与密封环泄漏痕迹对应处尺寸差D2-d2=0.08mm。 首次泄漏采取的维修措施为更换新的密封环。阀体中法兰密封面在试验台架上没有可靠的工装和技术保证研磨密封面的圆度,故密封面没有研磨,仅进行了表面光洁度处理。 新密封环外圆密封面直径d=120.16mm,比图纸要求的上限值大0.196mm,与阀体中法兰密封面轴线方向直径间隙为D1-d=0.02mm,横轴线方向直径间隙D2-d=0.08mm,配合间隙符合图纸给定的允许配合{zd0}间隙(0.291mm)。同时设想通过试验压力提供的密封力使新密封环在轴线方向(阀体中法兰密封面的短轴方向)发生过量塑性变形来加大横轴线方向(阀体中法兰密封面的长轴方向)的密封比压,避免长横轴线方向可能产生的泄漏。 新密封环在试压(常温试验压力为15.2MPa)过程中实现了阀体中法兰密封副的密封,并在常温试验压力的条件下再次对密封预紧螺栓进行预紧,加大密封环的变形量,使横轴线方向间隙尽{zd0}可能的得到弥补,保证密封副密封所需的密封比压。 3.2、2次泄漏和拆检 试验台架再次热态工况运行试验时,在高温高压(压力14.0MPa、温度240℃)运行超过4h后,当压力下降至8.9MPa、温度212℃左右时,该阀在中法兰密封副处再次又发生泄漏(以下称第2次泄漏)。经再次拆解阀盖和密封环检查,泄漏的具体部位在中法兰密封面横轴方向的两端密封面处,与轴线对称,其泄漏痕迹为可以去除铁红色(与其他部位不同)。对应的密封环外密封面锐角处有宽约20mm、轴向长6mm、左右对称的2处泄漏冲刷痕迹,痕迹现象为密集线状沟痕,阀体中法兰密封面其他部位、密封环外密封面的其他部位、密封环内密封面及封头密封面等处未见泄漏痕迹。 阀体中法兰密封面与首次泄漏检查测量一致,密封环在拆解过程中有变形,密封环的外密封面尺寸故没有测量。 4、分析 4.1、首次泄漏原因 (1)密封环毛虫状痕迹泄漏处疑似材料的内部缺陷,可能是材质锻造内部缺陷。在交变压力、交变高温高压及{zg}工作压力和温度作用下,导致密封环泄漏处材质锻造内部缺陷不断扩展,在锻造内部缺陷处产生介质泄漏。 (2)阀体中法兰密封面直径尺寸不一致,在轴线方向尺寸限制了密封环的上浮,导致了在横轴方向的密封比压小。由其在交变压力、交变高温高压及{zg}工作压力和温度作用时,轴线方向尺寸更加限制了密封环的上浮,并可能使横轴方向密封比压下降,不能保证密封的要求,发生介质泄漏,冲刷扩展了密封环的锻造内部缺陷,随着时间发展泄漏量将不断扩大。 4.2、第2次泄漏原因 (1)阀体中法兰密封面在横轴方向和轴线方向存在的尺寸误差没有进行修复。密封环外密封面在阀体中法兰密封面的密封中两个方向的间隙不一致,阀体中法兰密封面在沿通道轴线方向与密封环外密封面的间隙小,阀体中法兰密封面在横轴线方向与密封环外密封面的间隙大。介质压力(阀门检修后提供的{zg}试验压力15.0MPa)提供给中法兰的密封力,在阀体中法兰密封副中沿着阀体通道轴线和横轴线方向的密封比压不一致。阀体中法兰密封副在横轴线方向密封比压小,且不能像产品出厂试验压力(42.0MPa)那样提供足够的密封力来增加阀体中法兰密封副在横轴线方向密封比压,满足高温高压及交变压力温度条件下介质的密封。 (2)密封环外密封面在阀体中法兰密封面的密封中两个方向的间隙不一致。在交变压力和温度作用下时,阀体通道轴线方向的间隙和阀体通道横轴线方向的间隙随着交变压力和温度作用,发生阀体通道横轴线方向的密封副密封比压降低不能保证密封,导致介质泄漏。 4.3、中法兰密封副误差原因 从零件的加工尺寸检测,阀体中法兰密封面在沿着阀体通道轴线方向和横轴线方向尺寸一致。密封环外密封面垂直方向测量尺寸基本一致,相差0.002mm(薄壁件属正常),密封环外密封面的圆度不影响密封(密封环内密封面与阀盖密封接解触时会将密封环外密封面校圆)。经分析和验证,阀体中法兰密封面沿轴线方向和横轴线方向尺寸不一致的原因是由于阀门整机进行42.0MPa强度及中法兰密封副密封试验所致。 5、参数选择 内压自封旋启式止回阀是按专用试验台架实际使用工况进行的设计。试验台架的技术参数引入有关阀门压力等级的非标准压力级和所规定的试验压力,即公称压力为28.0MPa,试验压力为42.0MPa。 阀体中法兰密封面在沿轴线方向和横轴线方向变形不一致和超过允许的变形值,从计算的角度分析是由于阀体中法兰密封面的强度不够,在试验压力的作用下,超过允许的变形量。 相同的旋启式止回阀按专用阀门设计。设计参数为设计压力17.16MPa,设计温度≤350℃,工作压力13.73MPa,水压试验压力21.45MPa。该产品应用在相同工况的其他试验台架上,工作几十年无一发生泄漏。 实际应用说明,阀门设计中应认真分析其工况参数,不能盲目的引入标准规定的参数。此阀的泄漏是由于引入标准中的非压力等级,并按标准的水压试验压力(42.0MPa)试验,又没有按此参数设计中法兰强度,出现阀体中法兰密封面在2个方向的变形不一致和过量变形。这种现象尤其不适应反复交变的高温高压运行工况。 6、结语 分析和使用结果证明,若依据台架的试验压力进行设计和试验,阀门就不会发生问题,即节省了材料又满足了台架工况需要。因此为某些特殊工程所设计的阀门产品,不能盲目的使用标准或引用标准中的高参数。如果阀门产品是专门为某个工程和台架专门设计(不是工程和台架选用标准阀门产品),一定要考虑满足工况参数和特殊工况条件,盲目引用标准中的高于台架和工程上的技术参数是不可取的。如果一定要选用标准中的高参数(这些参数在专用台架和工程的工况和试验上永远不使用的),则必须认真校核各部分的强度,这样做将会导致阀门结构增大,造成浪费,也不适合专用试验台架和工程上的特殊需要,一旦应用也可能给试验台架和工程上带来该产品发生泄漏的隐患。

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原文：
1 Overview Internal pressure seal structure is the self-styled high-temperature high-pressure valve in the flange seal pair frequently used forms, a test rig installed in the same two Vice-flange seal for the internal pressure of the structure of self-styled Swing-return valve. In the test bench of the work of many alternating pressure and temperature test is complete, again boost pressure test at room temperature before heating process, one of the swing check valve in the flange of the seal pair leaks, take maintenance measures did not resolve this valve leakage. And another swing check valves in the test bench for several years, also occurred in the flange seal leak vice. To this end the valve leakage through this analysis of the problem, explain some of the special test bench and engineering use of special valves product design and choice of design parameters need serious consideration. 2, the technical parameters Two swing check valve before the factory was P = 42.0MPa the machine valves in the flange seal strength and vice seal test, no leakage. (1) test bench Maximum working pressure of 14.0MPa Maximum working temperature of 260 ℃ Design pressure 17.2MPa Design temperature 350 ℃ Working Medium Water 65mm diameter pipe test loop Test bench pressure 21.5MPa Down to ambient pressure again after each heating step before the test pressure 15MPa (2) Swing Check Valve PN 28.0MPa (non-standard nominal pressure level) 65mm nominal bore Valve body, valve cover material 1Cr18Ni10Ti Seal Material N6 And test bench welding circuit connection 3, fault 3.1, the first leak and repair Test bench several times atmospheric pressure rose during the maximum working pressure and alternating pressure, alternating temperature (down by required number of rate changes in temperature and pressure) rose to a maximum working pressure, temperature, and the test run, down to normal temperature pressure maintenance. Room temperature before heating up again boost pressure test (P = 9.8MPa) process, the test bench of a swing check valve in the outer flange of Deputy Commissioner of micro leakage occurred (hereinafter referred to as the first leak). Disassemble valve cover, check the leak site seal ring, sealing ring in the cylindrical body flange sealing surface and sealing surface of a dielectric leakage traces left by the minor. Cylindrical seal ring sealing surface of the media leak sealing surface trace of the cylindrical axial acute Office 3 × 115mm length × width of the caterpillar-shaped mark, which traces through the sealing surface, with a magnifying glass observation of internal defects of suspected materials. In the body flange sealing surface in the media have a slight trace of leakage for the watermark, and the seal ring sealing surface outside the traces of the corresponding caterpillar-like. Exact location of the channel in the vertical body axis direction (hereinafter referred to as horizontal axis direction) of the flange sealing surface of one end of the valve body flange sealing surface in other parts of the seal ring sealing surface of other parts of the outer sealing ring sealing surface and the head No signs of leakage sealing surface, the sealing surface sealed indentation uniform. Maintenance in the dismantling of the swing check valve in the flange seal pair when this valve in the flange sealing surface and the cylindrical seal ring sealing surface diameter size were measured. The flange sealing surface and seal ring outer sealing surface diameter in two perpendicular directions appear inconsistent with the length of the shaft phenomenon, body horizontal line in the direction of long axis, short axis of the channel along the body axis direction (hereinafter referred to as the axis direction). Body flange sealing surface in the short axis difference D2-D1 = 0.10mm, Seal length of shaft outside the sealing surface, a difference of d2-d1 = 0.04mm. Body flange sealing surface in the short axis and vertical seal ring leakage traces of size difference corresponds Department D1-d1 = 0.02mm, body flange sealing surface and seal in the leakage of traces of the corresponding ring size difference Division D2-d2 = 0.08mm. Measures taken to repair the first leak was replacement of the seal ring. Body in the flange sealing surface in the test bench without tooling and technology to ensure reliable sealing surface grinding roundness, so the sealing surface is not abrasive, just for a surface finish treatment. The new cylindrical seal ring sealing surface diameter d = 120.16mm, than the upper limit of drawings big 0.196mm, and the body axis in the flange sealing surface diameter clearance for the D1-d = 0.02mm, horizontal line of the direction of D2-diameter clearance d = 0.08mm, with line drawings of a given space with the maximum gap allowed (0.291mm). Also envisaged to provide the test pressure by the sealing strength of the new sealing ring in the axial direction (body flange sealing surface in the short axis direction) to increase the occurrence of excessive plastic deformation of the horizontal axis line direction (body axis in the flange sealing surface direction) than the pressure seal, to avoid long horizontal line of the direction of possible leakage. The new sealing ring in the test pressure (test pressure at room temperature as 15.2MPa) Body in the process of realization of the flange seal pair of sealed and at room temperature under the conditions of the test pressure seal preload once again tightening the bolts to increase seal ring the deformation, so that the direction of horizontal lines to get clearance to make up the greatest extent possible, to ensure the necessary sealing sealing sealing Vice specific pressure. 3.2,2 leaks and dismantling times Test bench to run again thermal test conditions, the high temperature and pressure (pressure of 14.0MPa, the temperature 240 ℃) to run more than 4h, when the pressure was 8.9MPa, the temperature around 212 ℃, the valve in the Flange Sealing Department once again has a leak (hereinafter referred to as 2nd leak). After dismantling valve cover again and check the seal ring, the exact location of leaks in the flange sealing surface in the direction of both ends of the horizontal sealing surface Department, with the axis of symmetry, the leakage can remove traces of iron for the red (and other parts of the different) . The corresponding seal ring sealing surface an acute angle outside the Department has wide 20mm, axial length 6mm, the two symmetrical leakage scour marks, traces the phenomenon of linear grooves for the intensive, body flange sealing surface in other parts of the outer sealing ring sealing surface of the other parts of the seal ring sealing surface and sealing the first sealing surface, etc. No signs of leakage. Body in the flange sealing surface and the first measurement of the same leak check, seal ring is deformed in the dismantling process, the outer seal ring sealing surface size and there is no measurement. 4, analysis 4.1, the first time, leakage (1) caterpillar-shaped sealing ring material traces of suspected leaks of internal defects, may be forging material within the defect. In the alternating pressure, high temperature and pressure and the highest alternating work under pressure and temperature, resulting in leaks seal ring material forging ever-expanding internal defects, defect in the forging internal leakage generated media. (2) the valve sealing surface of flange diameter of inconsistent size limits in the axis direction of the floating ring seal, resulting in the horizontal direction than the pressure seal small. By the alternating pressure, alternating high temperature and pressure and maximum working pressure and temperature effect, the axis direction of a more limited size of the floating ring seal, and may enable the horizontal direction than the pressure seal down, can not guarantee that the requirements of sealing, place media leakage, erosion of the sealing ring of Forging extended internal defects, the development of leakage over time will expand. 4.2, 2nd Leakage (1) body flange sealing surface in the horizontal direction and axial direction in the presence of the size of the error is not repaired. Outside the seal ring sealing surface on the body flange sealing surface in sealing the gap in both directions inconsistent body flange sealing surface in the channel axis direction along the outer seal ring sealing surface of the gap is small, the flange valve horizontal line in the direction of the sealing surface and seal ring sealing surface of the space outside the major. Medium pressure (valve repair provides the maximum test pressure after the 15.0MPa) sealing flange provided to the force in the flange in the valve body seal pair of channels along the body axis and the horizontal axis line direction sealing pressure than the inconsistency. Body Sealing of flange seals in the horizontal axis direction smaller than the pressure, and not the factory test pressure as the product (42.0MPa) as to provide sufficient sealing force to increase the body seal pair of flange sealing in the horizontal axis direction than the pressure to meet the high temperature and pressure and alternating pressure and temperature conditions, the sealing medium. (2) outside the seal ring sealing surface on the body flange sealing surface in sealing the gap in the two directions are inconsistent. In alternating under pressure and temperature, the body axis direction of channel clearance and body-channel horizontal lines alternating direction of the gap with the pressure and temperature effect, place the horizontal axis line direction of body channel sealing Sealing lower than the pressure can not assurance seal, leading to media leaks. 4.3, the pair error causes flange Size from the machining test, body flange sealing surface in the channel along the body axis and the horizontal axis direction of the same size. Outside the seal ring sealing surface of the vertical size measurement is consistent, a difference of 0.002mm (thin wall is normal), seal ring sealing surface outside the circle does not affect the degree of sealing (seal ring seal surface and the valve cover seal will be sealed when received contact solution outer ring sealing surface round the school). The analysis and verification, body flange sealing surface in the direction along the axis and the horizontal axis direction of size inconsistency is due to be 42.0MPa machine valve flange seal strength and the Vice-sealing test result. 5, parameters Internal pressure self-styled swing check valve is based on the actual use of special test bench for the design condition. Test bench of the technical parameters into the non-standard pressure valve pressure levels and the required level of test pressure, the nominal pressure was 28.0MPa, test pressure of 42.0MPa. Body flange sealing surface in the direction along the axis and the horizontal axis direction of deformation and more than inconsistent to allow the deformation, from the point of view of calculation is due to the sealing surface of flange body strength is not enough, the role of pressure in the test, more than allowable deformation. The same swing check valve according to specific design. Design parameters for the design pressure 17.16MPa, design temperature ≤ 350 ℃, working pressure 13.73MPa, water pressure test, 21.45MPa. The product used in the same condition in other test bench, working for several years without a leak. Practical application shows that the valve should be carefully analyzed the design and operation parameters and the introduction of standards can not be blind requirement parameters. This valve leakage is due to the introduction of standard non-pressure levels, according to the standard hydrostatic test pressure (42.0MPa) test, and no flange design parameters of intensity here, appears in the body flange sealing surface in two deformation direction is inconsistent and excessive deformation. This is especially not suited to repeated alternating high temperature and pressure operating conditions. 6 Conclusion Analysis and use of the results shows that a bench trial based on the design and test pressure, valve will not be a problem, that is, saving material also meets the needs of rig condition. So for some special projects designed valve products which are not blind to use standard or reference standard in the high parameter. If the valves are designed for a particular project and platform specifically designed (not a standard engineering and rig selection valve products), we must consider the needs of working parameters and special working condition, blind in the above referenced standard bench and engineering technical data is not desirable. If we must choose the high standard parameters (these parameters and works dedicated bench trial on the condition and never used), then all parts must be carefully checked the strength to do so will result in increased valve structure , resulting in waste and not for dedicated test bench and works on special needs, once the application is also possible to test bench and works to bring the hidden dangers of the product leak.