Service Recommendations and Limitations of Stop Check Valves
1. 截流止回阀最适用于低流速或中流速应用环境。截流止回阀的通径正确计算选择非常重要。管线流速太低或太高都可能损坏阀内件，缩短阀门的使用寿命。
Stop-check valves are best suited for low to moderate velocity applications. Correct sizing of stop-check valves is important. Either too low a line velocity or too high a velocity can damage valve internals and shorten valve life.
2. 应该避免应用在频繁出现流体倒流和间断的应用系统中。截流止回阀应该安装在离泵和压缩机尽可能远的地方。如果怀疑系统可能有问题，则在选型和订购截流止回阀之前，应该与美国太平洋阀门公司一起重新审核管道系统。
Service in systems involving frequent flow reversals and pulsation should be avoided. Stop-check valves should be located as far away from equipment such as pumps and compressors as possible. Suspected problem systems should be reviewed with Pacific Valves before selecting and purchasing stop-check valves.
3. 当用于高速流体(湍流)或热循环应用时，为了避免松开，螺纹阀座环应该锁焊在阀体上。请在订购时加以指定说明。
Threaded seat rings in valves in services with high velocity (turbulent) flow or thermal cycling should be lock welded to the body to avoid loosening. Please specify.
局限性
LIMITATIONS
1. 截止阀类型的节流止回阀可以用在水平管道上，阀杆垂直向上。
Globe pattern stop-check valves can be used in horizontal piperuns with the stem straight up.
旋启式止回阀应用建议
Service Recommendations for Swing Check Valves
1. 旋启式止回阀最适用于中流速应用环境。旋启式止回阀通径的正确计算和选择非常重要。管线流速太低或太高都可能损坏阀内件，缩短阀门的使用寿命。
Swing check valves are best suited for moderate velocity applications. Correct sizing of swing check valves is important. Either too low a line velocity or too high a velocity can damage valve internals and shorten valve life.
2. 应该避免应用在高流速，频繁倒流，间断或剧烈湍流的应用系统中。旋启式止回阀应该安装应该远离弯头等其它设备，这样通常可以减少或消除这些设备可能产生的问题。如果怀疑系统可能有问题，则在选型和订购旋启式止回阀之前，应该与美国太平洋阀门公司一起重新审核管道系统。
Service in systems involving rapid and frequent flow reversals, pulsation or excessively turbulent flow should be avoided. Locating swing check valves away from elbows, equipment, etc., within the piping system can often minimize or eliminate problems caused by this type of application. Suspected problem systems should be reviewed with Pacific Valves before selecting and purchasing swing check valves.
3. 旋启式止回阀通常适用于安装在水平管道上。如果阀瓣止回结构能够利用流体轻微的支撑住阀瓣，则这种阀门也可以应用在垂直管道上(仅限于流向朝上)。如果阀门准备用在垂直管道上，在订购时应该明确指定说明。
Swing check valves are normally designed for installation in horizontal pipe runs. When disc stops are designed to hold the disc slightly into the flow stream, the valves may also be used in vertical pipe runs (with flow up only). When valves are to be used in vertical pipe runs, this should be clearly specified.
4. 一般来说，外置杠杆和压铁对于通径大于DN160的旋启式止回阀，并无法有效防止阀门的拍击现象。
Generally, outside lever and weights are not effective in preventing slamming of swing check valves in sizes above 6".
5. 当用于高速流体(湍流)或热循环应用时，为了避免松开，螺纹阀座环应该锁焊在阀体上。请在订购时加以指定说明。
Threaded seat rings in valves in services with high velocity (turbulent) flow or thermal cycling should be lock welded to the body to avoid loosening. Please specify.
