截止止回阀
GLOBE CHECK VALVES

　　截止止回阀是一种具有防止流体倒流功能的截止阀。在开启状态下，这种阀门功能与提升式止回阀相同。在关闭状态下，这种阀门正如截止阀一样，通过阀杆推力将阀座封闭住。截止止回阀必须安装成阀杆垂直向上，并且流体从阀瓣下端流进的模式。当阀杆开启时，阀瓣下端的压力开启阀门，流体通过。流体出现倒流时，阀瓣关闭，流体中断。除了当阀杆处于关闭位置时具有双向绝对关闭能力以外，本章节中的截止止回阀的应用和限制与提升式止回阀相同。这种阀门的最常见应用是在泵的排泄口替代隔断阀(闸阀，截止阀或角阀)和止回阀，或者保护设备不受普通热水器的逆向倒流的破坏。美国太平洋截止止回阀可以配置《执行机构和附件》样本中的全系列手动或远程控制执行机构。
　　Stop check valves are globe valves with the added ability to prevent flow reversal. In the open position, they function as a lift check valve. In the closed position, they are seated by thrust from the stem like a globe valve. Stop check valves must be installed with the stem vertical and flow from below the disc. When the stem is opened, pressure from below the disc opens the valve and flow proceeds until it reverses. Uses and limitations of stop check valves included in this section are the same as lift check valves, except that they have this added ability to provide positive shutoff in either direction when the stem is in the closed position. Most common use of this type valve is to replace an isolation valve (gate, globe or angle) and a check valve on the discharge of pumps or to protect equipment from reverse flow from a common header. Pacific stop check valves are available with a complete range of manual or remote actuators covered in the Actuators and Accessories section of this catalog.

旋启式止回阀
SWING CHECK VALVES

　　旋启式止回阀在管道系统中用来防止流体倒流，适用于水平或垂直(通过阀门的流体流向朝上的)管道中。旋启式止回阀压降较小，最适合用于中等流速的应用环境中。旋启式止回阀的通径正确计算非常重要(参阅第22页)。管线流速太低或太高都可能会损坏阀内件，缩短阀门的使用寿命。应该避免应用在迅速和频繁倒流，脉冲波动或湍流的管道系统中。在管道系统内重新定位旋启式止回阀常常可以减少或消除这种类型应用所产生的问题。美国太平洋阀门愿意为用户的应用提供建议。
　　Swing check valves are used to prevent flow reversal in piping systems. They are suitable for service in horizontal or vertical (flow up through valve only) piping runs. Swing check valves have low pressure drop and are best suited for moderate velocity applications. Correct sizing of swing check valves is important (see page 22). Either too low a line velocity or too high a velocity can damage valve internals and shorten valve life. Service in systems involving rapid and frequent flow reversals, pulsation or turbulent flow should be avoided. Relocating swing check valves within the piping system can often minimize or eliminate problems caused by this type of application. Pacific Valves will be glad to advise you on your application.

美国太平洋阀门所适用的标准
PACIFIC VALVES CODES AND STANDARDS

　　美国太平洋阀门公司在阀门的设计和制造过程中，结合了多年的研究和开发成果和所有类型阀门的实际应用经验，采用优质的材料和工艺和现代化的制造方法和设备，确保阀门的可靠性和一致性。美国太平洋阀门公司的阀门结构符合下列标准的最新版本的要求：
　　API – 美国石油协会
　　MSS – 美国阀门和连接件行业制造商标准协会
　　ANSI – 美国国家标准协会
　　ASME – 美国机械工程师协会
　　Years of research and development, together with practical experience in reconditioning all types of valves, have gone into the design and manufacture of Pacific valves. High quality material and workmanship, combined with the modern manufacturing methods used in producing these valves, is your assurance of a dependable, uniform product. Pacific valves are designed in accordance with applicable requirements of the latest edition of the following standards.
　　API – American Petroleum Institute
　　MSS – Manufacturers' Standardization Society of the Valve and Fittings Industry
　　ANSI – American National Standards Institute
　　ASME – American Society of Mechanical Engineers