原文：
一、概述 　　高压液氨泵P101A/B是尿素装置的关键设备，是20世纪80年代从美国SUNDSTRAND公司引进的HMP-5112型高速离心泵，工作状态为一开一备，出口设计压力为27MPa，高速轴转速为20445R/min；其出口止回阀为单瓣旋启式高压自密封止回阀，结构形式及基本参数如表1所示，主要作用为在P101A/B倒泵时自动关闭，防止高压介质倒流而导致泵叶轮倒转，起保护P101泵的作用。经过十几年的运行，两台阀严重内漏，且P101A泵出口止回阀外漏，上述两种故障如不及时解决，将严重影响尿素装置的安全生产，因此对其进行了解体检修，因泵出口止回阀同时存在内外漏，以下就以该阀为例进行介绍。 　　二、检修时该阀存在的问题 　　(1)该阀因阀心长期处于工作状态，使阀心穿轴孔磨成椭圆，导致阀心下沉，频繁开启把阀座密封面下方严重损坏，从而造成严重内漏。 　　(2)该阀因制造缺陷和介质腐蚀等原因，阀体外密封部分出现了裂痕，导致液氨外漏。 　　三、检修方案 　　由于该阀为焊接阀，受检修时间的限制，不能离线修理。决定使用现场修复的方法进行修复。修复针对外漏和内漏两个方面同时进行： 　　1.外漏修复方案 　　(1)用小型电磨机手工打磨阀体外密封面裂痕，同时进行表面着色探伤，直至裂纹缺陷全部xx。 　　(2)选用A402焊条(铬26镍21不锈钢焊条)，用加热点焊法补焊阀体外密封面打磨处。 　　(3)用小型电磨机手工打磨焊接处，使其高度与阀体内表面基本平齐。 　　(4)制作内环式研磨环。 　　(5)用制作的研磨环手工对密封面进行研磨，磨后的内径：160.7mm。 　　(6)根据磨后的内径配作密封环。 　　2.内漏修复方案 　　(1)用便携式研磨机研磨阀座密封面。保证其在硬质合金存在的情况下恢复为圆形。 　　(2)在车床上用四卡定位找到原阀心穿轴孔中心，同时进行扩孔。 　　(3)车制两个环(1Gr18Ni9Ti)镶在扩孔中。保证其在中心不变的情况下，能够与穿轴合理配合，并点焊固定。 　　(4)车制穿轴(1Gr13)。 　　(5)用硬质合金D547钼焊条补焊阀头，根据研磨后的阀座孔配修阀头密封面。 　　(6)试配后用红丹试验，保证其密封性。 　　四、结束语 　　按照上述方案对高压液氨泵P101出口止回阀进行检修后，很好地解决了该阀泄漏问题，经过一年多的运行，使用效果良好，此次检修对同类型厂高压止回阀及其他自密封阀有一定的借鉴作用。

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译文：
I. Introduction High-pressure ammonia pump P101A / B is the key equipment of urea is 80 years, from the 20th century, the United States SUNDSTRAND HMP-5112 the company introduced high-speed centrifugal pump, the working conditions for the opening and preparation, export design pressure 27MPa, high-speed shaft speed To 20445R/min; its export Swing Check Valve is ill with high-pressure self-sealing valve, structure and basic parameters such as table 1 shows, the major role in the P101A / B pump automatically shut down to prevent the high pressure media back caused by the pump impeller reverse the protective role of P101 pump. After ten years of operation, the two serious internal valve leakage, and P101A pump outlet check valve leakage, the two failure if not resolved, would seriously affect the safety of urea production plant, so to understand their physical repair, exist due to internal and external pump outlet check valve leakage, the following will be introduced to the valve as an example. Second, when the valve repair problems (1) the valve is working because of long-term heart valve condition, the valve shaft through hole ground into elliptical heart, causing heart valve sink, often open to serious damage to the bottom of the valve seat sealing surface, resulting in serious leakage. (2) of the valve due to manufacturing defects and medium corrosion and other reasons, outside the sealed body portion of the rift, leading to leakage of liquid ammonia. Third, maintenance programs As the valve is welded valve repair by the time constraints, can not be off-line repair. Decided to use the method to repair on site repair. Repair for leakage and internal leakage both at the same time: 1. Leak repair program (1) mini-mill grinding with outside valve sealing surface cracks, while the surface color detection, until the crack defects completely removed. (2) selection of A402 electrode (Cr 26 Ni 21 stainless steel electrodes), with the heat welding method and fix the sealing surface grinding place outside the body. (3) hand-polished with a small electric welding mill, to a high degree of basic flush with the surface of the valve body. (4) Production of inner grinding ring. (5) produced by grinding with a hand on the seal ring surface grinding, grinding diameter after: 160.7mm. (6) The diameter distribution after grinding for sealing rings. 2. Endoleak repair program (1) Portable grinding machine with the seat sealing surface. Ensure the presence of the carbide to restore a circle. (2) with four cards in the car bed positioning to find the original heart valve shaft hole through center, at the same time reaming. (3) vehicle system of two rings (1Gr18Ni9Ti) fitted in a reaming in. Ensure the Centre remains unchanged, the ability to wear a proper combination of shaft and a fixed spot. (4) vehicles through the system axis (1Gr13). (5), molybdenum carbide D547 repair welding electrode valve head and valve seat after the hole under the ground with the first valve sealing surface repair. (6) test with post-test with red lead, to ensure the sealing. IV Conclusion In accordance with the program on high-pressure ammonia pump P101 to overhaul export valve, the valve solves the leakage problem, after a year of operation, with favorable results, the maintenance of the same type of plant high-pressure valve and other self-sealing valves have some reference.