选型
Selection

　　阀门种类和通径 – 为计划应用的领域选择最适合的阀门种类(闸阀，截止阀，或者止回阀)。闸阀和截止阀具有各种楔形闸板或阀瓣和阀体的配置，适用于不同的应用场合。可以根据现存的管道来确定阀门的通径，也可以根据实现最长使用寿命的流体条件来确定通径。
　　TYPE AND SIZE – Select the best type of valve for the intended service (gate, globe, or check). Gate and globe valves are available with a selection of wedge or disc and body configurations for different services.Valves may be sized to match existing lines, but they should also be sized according to flow conditions for maximum service life.
　　额定压力 – 所采用的阀门只能够用在阀门所标注的针对阀门等级额定值和阀体/阀帽材料的ANSI压力-温度额定值的设计条件范围内(参阅技术参数章节)。
　　RATINGS – Valves must only be used in design conditions within the appropriate ANSI pressure-temperature ratings for valve class rating and body/bonnet material (see Technical Data section).
　　温度局限 – 阀门只能够在其结构温度局限范围内使用。阀体/阀帽材料的局限，阀内件、螺栓和填料及垫圈的温度局限，全都必须考虑到。如果需要，也可以提供特殊结构的、具有更广泛温度局限范围的阀门。
　　TEMPERATURE LIMITATIONS – Only use valves within the temperature limitations of their construction. Temperature limitations of body/bonnet materials, trim, bolting and packing and gaskets must all be considered. Special construction for extended service temperatures are available on application.
　　材料和应用 – 压力密封阀门具有宽广范围的阀体/阀帽材料和阀内件供用户选择。特殊的材料应该与应用场合相兼容。
　　MATERIAL AND SERVICE – Pressure Seal valves are available in a variety of body/bonnet materials and trims. Specified materials should be compatible with the service.

闸阀
GATE VALVES

1. 闸阀通常用于启闭应用场合。不适用于节流应用场合。
   Gate valves are normally used for on-off service. They are not recommended for throttling service.
2. 闸阀通常安装在水平管道上，其阀杆垂直向上。闸阀也可以安装在垂直或水平管道上，其阀杆并不是垂直向上，但是此时要求具有特殊的结构，取决于阀门通径、应用条件和材料等因素。如果订购的阀门不是用于正常的安装方式，则在订购时，应该咨询厂家并指定阀门的流向。
   Gate valves are normally installed in horizontal pipe runs with the valve stem vertically up. They can also be installed in vertical or horizontal pipe runs with the valve stem other than vertical, but special construction may be required depending on valve size, service conditions and material. When purchasing valves for other than the normal installation, valve orientation should be specified when consulting the factory.
3. 在以足够的力量关闭闸阀后，应该是阀杆稍微回转一点(1/8至1/4转)，以减轻阀杆的负载。这将使得阀杆能够稍微扩张，不至于弯曲或损坏阀门，也不影响阀门的关闭。
   After closing a gate valve with sufficient force to develop shutoff, the stem should be backed off slightly (1/8 to 1/4 turn) to relieve stem load. This will enable the stem to expand slightly without bending or damaging the valve and will not affect valve shutoff.
4. 我们提供的闸阀的结构形式具有两种：平行阀瓣和弹性楔形闸板。平行阀瓣为定位阀座密封；弹性楔形闸板在关闭时则是扭矩阀座密封。
   Gate valves are offered in two designs: Parallel Disc and Flexible Wedge. Parallel Disc are position seated; Flexible Wedge are torque seated when closing.