阀门选购的质量检查需兼顾外观、材质、性能等维度，通过细致观察与简易测试，判断是否符合使用需求。

　　The quality inspection of valve selection should take into account dimensions such as appearance, material, and performance. Through careful observation and simple testing, it is determined whether it meets the usage requirements.

　　外观检查直观反映质量。铸铁阀门表面应无直径超 2mm 的砂眼、气孔，涂层均匀无剥落；不锈钢阀门需有均匀金属光泽，无氧化斑与划痕，抛光面纹路一致。连接部位加工精度关键：法兰密封面用直尺贴合，缝隙不超 0.1mm；螺纹接口牙型完整，无断牙滑牙，如 DN50 阀门螺纹长度不小于 10mm。阀体标识需清晰，标注公称直径（如 DN100）、公称压力（如 PN16）、材质代号（如 WCB）等，标识模糊产品需谨慎。

　　Visual inspection provides a clear reflection of quality. The surface of cast iron valves should have no sand holes or air holes with a diameter exceeding 2mm, and the coating should be uniform without peeling off; Stainless steel valves should have a uniform metallic luster, no oxidation spots or scratches, and a consistent polished surface pattern. The key to the machining accuracy of the connecting parts is to use a ruler to fit the flange sealing surface, with a gap of no more than 0.1mm; the thread interface has a complete tooth shape without broken or sliding teeth, such as DN50 valves with a thread length of no less than 10mm. The valve body identification should be clear, indicating the nominal diameter (such as DN100), nominal pressure (such as PN16), material code (such as WCB), etc. If the identification is unclear, caution should be taken.

　　材质验证要与标称一致。碳钢阀门可被磁铁吸附，不锈钢（如 304）通常不吸或弱吸附，必要时核对材质证明书（304 不锈钢铬≥18%、镍≥8%）。塑料阀门（PVC、PPR）按压无明显变形，弯折阀杆有弹性不易断。腐蚀性介质用阀需确认过流部件耐腐性，如衬氟阀门的氟塑料层应均匀无气泡，厚度不小于 2mm。

　　The material verification should be consistent with the nominal value. Carbon steel valves can be magnetically adsorbed, while stainless steel (such as 304) usually does not or weakly adsorb. If necessary, check the material certificate (304 stainless steel chromium ≥ 18%, nickel ≥ 8%). Plastic valves (PVC, PPR) have no obvious deformation when pressed, and the bent valve stem has elasticity and is not easily broken. Valves used for corrosive media require confirmation of the corrosion resistance of the overcurrent components. For example, the fluoroplastic layer of fluorine lined valves should be uniform and free of bubbles, with a thickness of not less than 2mm.

　　密封性能是核心检查项。手动测试关闭密封性：关闭阀门时阀杆转动顺畅，无卡滞过松（球阀 90° 灵活转动，闸阀升降平稳）；小型阀门关闭后向进口吹气，出口应无泄漏，大型阀门可要求提供打压数据（1.5 倍公称压力下保压 30 分钟无渗漏）。填料函需密封良好，反复转动阀杆无明显渗漏（允许微量湿润，不滴漏）。法兰连接阀门的垫片要与密封面匹配（橡胶垫适用于低压，金属缠绕垫适用于高压），且无破损褶皱。

　　Sealing performance is the core inspection item. Manual testing of sealing performance: When closing the valve, the valve stem rotates smoothly without any jamming or looseness (the ball valve rotates flexibly at 90 °, and the gate valve rises and falls smoothly); After the small valve is closed, blow air into the inlet, and there should be no leakage at the outlet. For large valves, pressure data can be requested (maintain pressure for 30 minutes at 1.5 times the nominal pressure without leakage). The packing box needs to be well sealed, and there should be no obvious leakage when the valve stem is repeatedly rotated (allowing for slight wetting without dripping). The gasket of the flange connected valve should match the sealing surface (rubber gasket is suitable for low pressure, metal wrap gasket is suitable for high pressure), and there should be no damage or wrinkles.

　　操作机构需灵活耐用。手柄或手轮安装牢固，转动时与阀杆无松动，如 DN200 阀门手柄长度不小于 200mm，转动省力不打滑。电动或气动阀门接通电源（气源）后，启闭应到位平稳，无异常噪音，限位装置准确。轴承、导向套等部件需润滑良好，转动阀杆无卡涩。

　　The operating mechanism needs to be flexible and durable. The handle or handwheel is securely installed and does not loosen with the valve stem during rotation. For example, the length of the DN200 valve handle should not be less than 200mm, and it should be easy to rotate without slipping. After the electric or pneumatic valve is connected to the power (gas source), it should open and close smoothly, without any abnormal noise, and the limit device should be accurate. The components such as bearings and guide sleeves need to be well lubricated, and the rotating valve stem should not be stuck.

　　性能参数要适配使用场景。高温管道用阀公称压力不低于工作压力 1.25 倍，碳钢阀门耐温≤425℃，不锈钢可达 600℃。输送粘稠介质的阀门需流道通畅，阀芯结构防堵，如球阀通径与管道一致。频繁操作的阀门（如水处理系统），阀杆表面硬化处理（镀铬层≥0.05mm），避免频繁使用导致磨损。

　　The performance parameters should be adapted to the usage scenario. The nominal pressure of valves used in high-temperature pipelines shall not be less than 1.25 times the working pressure, carbon steel valves shall have a temperature resistance of ≤ 425 ℃, and stainless steel valves shall have a temperature resistance of up to 600 ℃. Valves that transport viscous media require unobstructed flow channels and anti clogging valve core structures, such as ball valves with the same diameter as the pipeline. Valves that are frequently operated (such as water treatment systems) should have their valve stem surface hardened (chrome plating ≥ 0.05mm) to avoid wear and tear caused by frequent use.

　　总之，阀门选购需从外观、材质、密封、操作多维度检查，结合使用场景要求，必要时参考专业检测数据，才能选到可靠产品，减少后期隐患。

　　In short, valve selection needs to be checked from multiple dimensions such as appearance, material, sealing, and operation, combined with the requirements of the usage scenario. If necessary, professional testing data should be referred to in order to select reliable products and reduce potential hazards in the later stage.

　　本文由 良工阀门 友情奉献.更多有关的知识请点击  http://www.jnlgvf.com   真诚的态度.为您提供为全面的服务.更多有关的知识我们将会陆续向大家奉献.敬请期待.

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