原文：
　大多数截止阀使用T形阀体，可使阀门安装在直通的管线上。物流通过入口进入阀的中心（阀芯位于此处）。在这里流动方向转变90°然后通过阀座，随后又一个90°转变而流出阀门。 　　截止阀的流动方向由制造商或操作工况而定，但是大多数工况，流动方向几乎永远位于阀芯之下。将发信对着流动方向放置，他有恒定的阻力但是足以克服的。对于阀芯下流动，阀门相对地容易关闭而且流体压力和流量变化和少。此外阀芯下流动由于流体推动阀芯底部而容易开启。 手动截止阀可以调节成百分比型、直线型或快开型流动特性。如2.2节详细解释那样，流动特性决定阀门某一位置的预期流率（用流动系数CV）表示。这样对某{yl}动特性，用户可通过手动手轮的直线位置而确定流率。如果阀芯头位于节流位置（位于全开和全关之间），物流由于压力降而向阀座的流动开口处运动。在节流位置，阀芯头略微伸入到阀座环，在给定的流动特性的某一特殊位置上提供相应的流动。当退回并远离阀座，可达到较大的流量。如果进一步伸向阀座则形成较小的流量。当物流通过阀座运动时，流体压力减小而速度增加。流体进入截止阀较低部分后，流动面积再次加大，压力恢复而流速下降。 　　当流体进入阀座或阀的阀芯面积时，一个重要的设计考虑问题是阀体的工作台面积。在理性状态下，物流沿着阀芯和阀座自由循环，使物流能够由每一个方向进入阀座。如果在任何一个面积中工作台面积过窄（例如在旋塞的背面），速度可能增加，而导致噪音和磨蚀，或下游产生湍流。此处有不等的力作用在阀芯头，如果阀芯头未被阀座所导向，可导致阀芯头的轻微挠曲。 　　当截止阀关闭时，手轮的轴向力作用于旋塞。阀芯表面的力对阀座环的轻微不匹配的角度施加压力，而不允许任何物流通过闭合元件。在全开位置，整个阀座面积对物流打开以便流动。 　　依靠端面接头垫片的静密封将工艺物流保留在阀体和阀帽内【如果使用法兰或O形环接头（RTJ）】。阀帽填料盒的动密封防止了物流通过旋塞滑动杆的泄漏。根据用户的关闭要求，物流可以或不可以通过调节关闭元件本身的泄漏。

“ Valve operating norms ”是由提供的阀门新闻，译文仅供参考。另外，中国截止阀网还提供相关产品搜索： 、 、 、 、 、 、 、 、 。

译文：
Most use the T-shaped valve body, allows the valve installed in the through the pipeline. Logistics through the center of the entrance into the valve (spool is located here). Here changes in flow direction 90 ° and then through the seat, then a 90 ° change in the outflow valves. Cut-off valve of the flow direction by the manufacturer or operating conditions may be, but most conditions, the flow direction is almost always located under the spool. Letters against the flow direction will be placed, he has a constant resistance, but enough to overcome. Under the flow for spool valve closure and relatively easy changes in fluid pressure and flow and less. Besides promoting spool valve due to fluid flow under the bottom and easy opening. Manual cut-off valve can be adjusted as the percentage of type, linear or quick opening flow characteristics type. Such as 2.2, as explained in detail, the valve flow characteristics determine the expected flow rate of a position (with flow coefficient CV) said. This characteristic of a mobile user can hand wheel by hand to determine the location of the line flow rate. If the valve head in the throttle position (between fully open and fully closed), the pressure drop due to the logistics flow valve seat openings movement. In the throttle positions, the spool head slightly stuck to the seat ring, given the flow characteristics of a particular location to provide appropriate mobility. When the back and away from the valve seat, may achieve a larger flow. Further toward the valve seat is formed if a smaller flow. When the logistics movement through the valve seat, fluid pressure decreases the rate of increase. Fluid into the lower part of valve, the flow area is again increasing, pressure and flow rate decrease. When the fluid into the valve seat or valve spool area, an important design issue to consider is the body of the table area. Rational state, the logistics along the valve core and valve seat free circulation, so the logistics can be from every direction into the valve seat. If any one area of the table in a narrow area (such as cock's back), speed may increase, leading to noise and abrasion, or produce turbulence downstream. Here is the spool force, ranging from the first, if not the first valve seat by the orientation, can lead to a slight deflection of the first spool. When the valve is closed, the axial force on the hand wheel cocks. Spool surface of the force on the valve seat ring does not match the point of slight pressure, but the logistics do not allow any components through closure. In the fully open position, the valve seat area is open to the logistics flow. Rely on the static sealing gasket face joint logistics process will remain in the body and bonnet flange or within 【If O-ring joints (RTJ)】. Bonnet packing box seals to prevent the logistics of leakage through the cocks sliding bar. The closure according to the user requirements, logistics can and can not close the device by adjusting the leakage itself.