流量系数值
Cv Values

　　作为一般指南而言，水平安装阀门的开启和关闭压力范围从0.2到0.5 psi。阀门通径越大，开启阀门需求压力就越小。如果阀门安装在垂直向上的应用场合，则开启所需的压力会略有增加。
　　As a general guideline, Opening & Closing Pressures will range from 0.2 to 0.5 psi for horizontal applications. Opening pressure tends to decrease in larger size valves. Valves installed in vertical up-flow applications will require slightly higher pressures.

一般安装信息
General Installation Information

　　正常系统湍流可能会影响到蝶式止回阀的阀座。阀门应该安装在距离任何管件至少5倍管道直径远的地方。如果用作底阀，则不要安装在靠近罐底部的地方。蝶式止回阀不能用于连续循环流动的应用场合，如循环泵。否则可能导致密封膜过早破坏。如果是水平安装，则要始终保持铰柱螺栓朝向处于阀体外可观察的垂直位置（顶部和底部），并与流体流向相互垂直。如果垂直安装在某个弯管的下游位置，则弯管外径的流速可能会比较高。为了避免蝶式阀板负载不均衡，铰柱螺栓应该与弯管外径和交叉部对齐，不要从弯管的一侧穿到另一侧。
　　Butterfly Check Valve seating may be affected by normal system turbulence. Valves should be installed at least 5 pipe diameters away from any fitting. If used as a foot valve, do not place near bottom of a tank. Butterfly type check valves should not be used in continuous cycling applications, such as with reciprocating pumps. This can result in premature failure of sealing membrane. In horizontal installations, always orient the Hinge Post Bolts visible on the external body in a vertical (top and bottom) position, perpendicular to flow. In vertical installations downstream from an elbow, flow velocities can be higher on the outer radius of the elbow. To avoid uneven butterfly plate loading, the Hinge Post Bolts should align with crotch and outer radius of elbow and NOT from side to side of the elbow.