主要的阀门种类
Valve Function Basics

　　球阀
　　Ball Valves

　　球阀这个名称来源于位于阀体中心起着开启/关闭功能的浮动-控制的球体。一个孔穿过球体中心（阀孔），连接阀门两侧的进口和出口端，以实现流体的转移。这个球孔能够绕着与流体流向垂直的轴旋转90度角，以实现将流体阻止在“关闭”的位置上。这个球体定位在两个阀座之间，并起着“气密性”密封的作用，同时在阀门运转期间起着润滑的作用。在阀杆和密封腔之间采用弹性材料O形密封环来防止流体泄漏。在全开位置，压降实际上完全消除，因为阀孔与Schedule 80系统管道的管径完全相同。T型球阀是一种特殊结构的球阀，它在球阀的一端上结合着一个T型管件。这种结构保持阀门能够尽可能接近流体主管道，以在需要特殊应用的场合尽量降低潜在的流体淤积“单流管”现象出现的可能性。
　　Ball valves derive their name from the on/off function accomplished by means of a flow-controlling ball located in the center of the valve body. A hole through the center of the ball (valve bore) connects the inlet and outlet sides of the valve for fluid stream transfer. The ball rotates 90^o on an axis perpendicular to the fluid stream in order to block flow in the "off" position. The ball is held in place between two valve seats, which serve as a "bubble tight" seal off, while providing lubrication during valve operation. Elastomer O-rings are used in the stem and seal carrier to prevent fluid leakage. Pressure drop is virtually eliminated in the full-open position, since the valve bore is the same size as Schedule 80 system piping. The T-Style ball valve is a special configuration incorporating a Tee fitting at one end of the valve. This design maintains close proximity of the valve to the fluid mainline to minimize "dead leg" of potential fluid accumulation, where required by specific application.

　　3通球阀
　　3-Way Ball Valves

　　3通球阀是“分流”形式的球阀，为流体改变流向提供另一个端口。3通阀门结构包括垂直（底部分支端口）或水平（侧面分支端口）两种结构。我们也可以提供多通球阀，多通球阀在阀球上具有不同的孔结构，能够提供流体转向的不同选择。这些分流类型的3通球阀在分支端口上没有关闭功能。
　　3-Way ball valves are "diverter" style ball valves that provide an additional port to redirect the fluid stream. Valve configurations are either vertical (bottom branch port) or horizontal (side branch port). Multiple ball-port options are available in which different hole patterns in the valve ball provide alternative paths to divert flow. These diverter style 3-Way ball valves have no shutoff on the branch ports.

　　止回阀
　　Check Valves

　　止回阀是一种自动化运行的阀门，这种阀门当流体向前流动时处于开启状态，而当流体倒流时则处于关闭状态。准确的工作效果很大程度上取决于止回阀的机械结构类型。这些结构包括：球体结构（球体止回阀），旋启阀瓣结构（旋启式止回阀），“双阀瓣”结构（蝶型止回阀），重力塞结构（Y型止回阀），以及弹簧辅助止回阀结构系列。弹簧辅助止回阀结构系列包括：弹簧辅助旋启阀瓣结构（弹簧止回阀）和弹簧安装线性阀瓣结构（在线弹簧止回阀）。无论是什么结构类型，止回阀在阀体内部都有一个关闭装置，位于进口和出口之间，以便流体能够轻易地转变流向，并在流体出现倒流时能够向止回装置流动。倒流的流体通过倒流的流体压力将止回关闭装置与阀体紧密密封，从而实现阻止倒流的“止回”功能。美国斯毕尔公司所有球体止回阀和工业旋启式止回阀采用标准的弹性材料O形环密封。通用旋启式和弹簧止回阀，和蝶型止回阀采用弹性材料膜密封，在线弹簧止回阀和Y型止回阀采用弹性材料阀座。美国斯毕尔公司止回阀经过精心的工程设计和制造，最大限度减少压降，可以安装在水平位置或垂直位置，除了某些特殊结构的关闭装置以外。球体止回阀适用于没有碎片和颗粒进入的各种普通应用场合。蝶型止回阀占用空间最小，还有旋启式止回阀，则适用于包含颗粒或碎片的流体。此外，旋启式止回阀能够通过的流量更大。工业旋启式止回阀系列可以配置反平衡装置来进一步控制关闭速度。通用旋启式止回阀（弹簧辅助旋启式止回阀）有助于阀门的关闭，而在线弹簧止回阀可用来调节抵消开启压力。
　　Check valves are automatic valves that open with forward flow and close with reverse flow. Exact operation will vary depending on the type of check valve mechanism. These include a ball (Ball Check), a swinging disc (Swing Check), a "double disc" (Butterfly Check), a weighted plug (Y-Check), and spring assisted types of check devices. These include a spring assisted swinging disc (Spring Check) and a spring mounted linear disc (In-line Spring Check). Regardless of type, a check valve has a closure device positioned in the valve body between inlet and outlet so that the fluid stream is easily transmitted in the direction of flow, but is allowed to move against the check device in the event of flow in the reverse direction. Reversed flow is stopped or held in "check" by fluid backflow pressure which seats the closure device against the valve body. Standard elastomer O-ring seals are used in all Spears® Ball Check Valves and Industrial Swing Check Valves. Utility Swing and Spring Check Valves, and Butterfly Check Valves use an elastomer membrane seal; In-Line Spring Check Valves and Y-Check valves use an elastomer seat. Spears® Check Valves have been carefully engineered to minimize pressure drop and can be installed in either horizontal or vertial positions, within the limitations of the specific type of closure device. Ball Check Valves are well suited for general applications of fluids free from debris and entrained solids. Butterfly Check Valves have minimum space requirements and, along with Swing Check Valves, are better for use with fluids containing solids or debris. Swing Check Valves additionally allow higher volume of fluid transmission. Industrial Swing Check models can be fitted with an optional counter balance device to further control closing speed. The Utility Spring Check Valve (spring assisted Swing Check) aids in valve closing, while the In-Line Spring Check can be adjusted for resistance to opening pressure.

　　旋启止回球阀
　　Swing Check Ball Valves

　　旋启止回球阀是一种特殊结构，结合了球阀和旋启式止回阀的基本功能，用于需要串联球阀和止回阀的常规应用场合。
　　Swing check ball valves are a special design that combines the basic function of a ball valve and a swing check valve for use in general purpose applications where an in-line ball and check valve configuration is required.