译文：
1 　概述 球阀在石油、化工、冶金和城市集中供热等行业得到了广泛的应用。但是密封副用PTFE 高分子材料制造的球阀, 不能用于温度大于280 ℃或输送介质呈微小颗粒状的工况。而以金属材料作密封副的硬密封球阀, 在旋转球体时会因结构不同出现各种情况。如金属弹性阀座密封结构, 由于弹性阀座与球体之间并未形成间隙, 所以其摩擦力很大。金属浮动阀座密封结构其浮动阀座与阀体之间不易密封。组合球撑开式密封结构, 由于零部件多, 结构复杂, 增加了加工难度与制造成本, 尤其是小口径的硬密封球阀, 这种结构显然是不适用的。经过反复的分析和测试, 并借助于CAD 辅助设计, 成功研制了Q47H 凸轮偏心式单阀座固定型硬密封球阀。 2 　工作原理 凸轮偏心式单阀座的球体中心线相对于阀体中心线偏移a 、b , 阀座密封面偏心b。当阀杆绕O 点顺时针旋转90°, 则球体亦随之旋转90°, 并与阀座密封面紧密吻合, 当密封副间的摩擦力矩和填料与阀杆间的摩擦力矩大于介质压力形成的力矩时, 阀门将达到可靠密封。由于阀门密封采用凸轮式偏心结构, 当阀门开启时, 球体迅速脱离阀座密封面。阀门关闭时, 球体迅速与阀座密封面吻合。从而达到了开启扭矩小, 关闭严密的目的。 3 　结构特点 小口径阀门体腔空间窄小, 通常的结构设计已不适用。因此, 阀杆末端加工成扁形并带有短轴, 球体上下均有扁形槽及孔, 孔用于与上下阀杆连接起到固定球体, 限制球体自由度的作用, 同时起到平衡体腔与管线介质间压力的作用。扁形槽与阀杆配合, 传递来自于手柄的扭矩。 4 　制造加工 球体两孔的同轴度和球体中心线相对于阀体中心线的偏心尺寸公差要求比较严格, 一般需要镗床或数控机床加工。装配前阀座密封面与球体面应配研, 然后将球体置于关闭位置, 安装左阀体, 调整垫片, 拧紧螺钉, 静压灌水不漏, 则此阀在密封试验下即可保证密封。 5 　结语 小口径硬密封球阀符合国内外现有球阀结构长度、连接形式和连接尺寸相关标准, 该阀不但适用于输送气态或液态单相介质, 也适用于气液混合的介质和气液浆混合的介质。该阀门已应用于冶金、纺织和石油等行业, 效果良好。

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原文：
1 Overview Ball valve in the oil, chemical, metallurgical and other industries and urban central heating has been widely used. However Sealing PTFE polymer materials with the ball, can not be used for temperature higher than 280 ℃ or transport medium was small granular condition. The metal materials for seal pair of hard sealing ball valve, ball rotation will result in different structures to arise. Such as metal flexible seating structure, as flexible valve seat and ball does not form a gap between, so its great friction. Metal floating valve seat seal structure between the float valve seat and valve seal is not easy. Combined seal structure of the ball softened, as many parts, complicated structure, increasing the difficulty of processing and manufacturing costs, especially small diameter hard seal ball valve, this structure is clearly not applicable. After much analysis and testing, and the help of CAD, successfully developed Q47H eccentric cam fixed single seat Ball Valve. 2 Work Eccentric cam single seat of the ball relative to the body center line center line offset a, b, the valve seat sealing surface eccentric b. When the valve stem clockwise rotation around the O point of 90 °, the ball has also come to rotate 90 °, and in close agreement with the valve seat sealing surface, when the seal between the friction torque and the deputy and the stem packing friction between the moment more than medium pressure the formation of torque, the valve will reach a reliable seal. As the valve seal with eccentric cam structure, when the valve opens, the ball quickly from the seat sealing surface. Valve closed, ball quickly and fit the valve seat sealing surface. So as to achieve the opening torque is small, the purpose of closing tightly. Three structural features Small-caliber valve body cavity space narrow, usually of the structural design is no longer applicable. Therefore, the stem end and processed into a flat with a short axis, the upper and lower ball groove and the holes are flat, the upper and lower valve stem hole to connect with the play for a fixed sphere, the sphere limit the role of freedom, and balance the body cavity and pipelines media room pressure. Slot with the stem with the flat, passing from the handle of torque. 4 manufacturing process Coaxial two-hole ball and sphere center line center line of the eccentric relative to body size tolerance requirements more stringent, generally require boring machine or CNC machining. Before assembling the ball valve seat sealing surface and be equipped with decent research, and then placed in the closed position the sphere, the installation of left valve, adjusting the gasket, tighten the screws, static pressure irrigation does not leak, this valve can be guaranteed under the seal test seal. 5 Conclusion Small-bore Ball Valve ball valve structure consistent with the length of the existing home and abroad, to connect the form and dimensions relevant standards, the valve is not only suitable for single-phase transport of gaseous or liquid medium, also applies to gas-liquid mixture of medium and mixed gas-liquid slurry medium. The valve has been used in metallurgy, textile and oil industries with good results.