选择阀门的步骤和依据

Steps and basis for selecting valves

1选择步骤

1 select steps

（1）明确阀门在设备或装置中的用途，确定阀门的工作条件：适用介质、工作压力、工作温度等等。

(1) Specify the purpose of the valve in the equipment or device, and determine the working conditions of the valve: applicable medium, working pressure, working temperature, etc.

（2）确定与阀门连接管道的公称通径和连接方式：法兰、螺纹、焊接等。

(2) Determine the nominal diameter and connection mode of the pipeline connected with the valve: flange, thread, welding, etc.

（3）确定操作阀门的方式：手动、电动、电磁、气动或液动、电气联动或电液联动等。

(3) Determine the mode of valve operation: manual, electric, electromagnetic, pneumatic or hydraulic, electrical linkage or electro-hydraulic linkage, etc.

（4）根据管线输送的介质、工作压力、工作温度确定所选阀门的壳体和内件的材料：灰铸铁、可锻铸铁、球墨铸铁、碳素钢、合金钢、不锈耐酸钢、铜合金等。

(4) According to the medium transported by the pipeline, working pressure and working temperature, determine the materials of the shell and internals of the selected valve: gray cast iron, malleable cast iron, nodular cast iron, carbon steel, alloy steel, stainless acid resistant steel, copper alloy, etc.

（5）选择阀门的种类：闭路阀门、调节阀门等。

(5) Select the type of valve: closed-circuit valve, regulating valve, etc.

（6）确定阀门的型式：闸阀、截止阀、球阀、蝶阀、节流阀、减压阀、蒸汽疏水阀等。

(6) Determine the type of valve: gate valve, globe valve, ball valve, butterfly valve, throttle valve, pressure reducing valve, steam trap, etc.

（7）确定阀门的参数：对于自动阀门，根据不同需要先确定允许流阻、排放能力、背压等，再确定管道的公称通径和阀座孔的直径。

(7) Determine the parameters of the valve: for automatic valves, the allowable flow resistance, discharge capacity, back pressure, etc. shall be determined according to different needs, and then the nominal diameter of the pipeline and the diameter of the valve seat hole shall be determined.

（8）确定所选用阀门的几何参数：结构长度、法兰连接形式及尺寸、开启和关闭后阀门高度方向的尺寸、连接的螺栓孔尺寸和数量、整个阀门外型尺寸等。

(8) Determine the geometric parameters of the selected valve: structural length, flange connection form and size, size of valve height direction after opening and closing, size and quantity of connected bolt holes, overall size of the whole valve, etc.

（9）利用现有的资料：阀门产品目录、阀门产品样本等选择适当的阀门产品。

(9) Use the existing data: valve product catalog, valve product samples, etc. to select appropriate valve products.

2选择阀门的依据

2 basis for valve selection

在了解掌握选择阀门步骤的同时，还应进一步了解选择阀门的依据。

While understanding and mastering the steps of valve selection, we should also further understand the basis of valve selection.

（1）所选用阀门的用途、使用工况条件和操纵控制方式。

(1) The purpose, working conditions and operation control mode of the selected valve.

（2）工作介质的性质：工作压力、工作温度、腐蚀性能，是否含有固体颗粒，介质是否有毒，是否是易燃、易爆介质，介质的黏度等等。

(2) Properties of working medium: working pressure, working temperature, corrosion performance, whether it contains solid particles, whether the medium is toxic, whether it is flammable and explosive, viscosity of the medium, etc.

（3）对阀门流体特性的要求：流阻、排放能力、流量特性、密封等级等等。

(3) Requirements for valve fluid characteristics: flow resistance, discharge capacity, flow characteristics, sealing grade, etc.

（4）安装尺寸和外形尺寸要求：公称通径、与管道的连接方式和连接尺寸、外形尺寸或重量限制等。

(4) Installation dimension and overall dimension requirements: nominal diameter, connection mode and connection dimension with pipeline, overall dimension or weight limit, etc.

（5）对阀门产品的可靠性、使用寿命和电动装置的防爆性能等的附加要求。

(5) Additional requirements for the reliability and service life of valve products and the explosion-proof performance of electric devices.

选择阀门应遵循的原则：

Principles for valve selection:

1、截止和开放介质用的阀门

1. Valves for stop and open media

流道为直通式的阀门，其流阻较小，通常选择作为截止和开放介质用的阀门。向下闭合式阀门（截止阀、柱塞阀）由于其流道曲折，流阻比其他阀门高，故较少选用。在允许有较高流阻的场合，可选用闭合式阀门。

The flow passage is a straight through valve with small flow resistance. It is usually selected as the valve for cut-off and open medium. Downward closed valves (stop valve, plunger valve) are less selected because of their tortuous flow path and higher flow resistance than other valves. Where high flow resistance is allowed, closed valves can be selected.

2、控制流量用的阀门

2. Valve for controlling flow

通常选择易于调节流量的阀门作为控制流量用。向下闭合式阀门（如截止阀）适于这一用途，因为它的阀座尺寸与关闭件的行程之间成正比关系。旋转式阀门（旋塞阀、蝶阀、球阀）和挠曲阀体式阀门（夹紧阀、隔膜阀）也可用于节流控制，但通常只能在有限的阀门口径范围内适用。闸阀是以圆盘形闸板对圆形阀座口做横切运动，它只有在接近关闭位置时，才能较好地控制流量，故通常不用于流量控制。

Generally, the valve easy to adjust the flow is selected as the flow control valve. Downward closing valves (such as globe valves) are suitable for this purpose because its seat size is directly proportional to the stroke of the closing member. Rotary valves (plug valves, butterfly valves, ball valves) and flex body valves (clamp valves, diaphragm valves) can also be used for throttling control, but they are usually only applicable to a limited range of valve diameters. The gate valve uses a disc-shaped gate to make a cross cutting movement to the circular valve seat. It can better control the flow only when it is close to the closed position, so it is usually not used for flow control.

3、换向分流用的阀门

3. Valve for reversing and shunting

根据换向分流的需要，这种阀门可有三个或更多的通道。旋塞阀和球阀较适用于这一目的，因此，大部分用于换向分流的阀门都选取这类阀门中的一种。但是在有些情况下，其他类型的阀门，只要把两个或更多个阀门适当地相互连接起来，也可作换向分流用。

The valve can have three or more channels according to the needs of reversing and shunting. Plug valves and ball valves are more suitable for this purpose. Therefore, most of the valves used for directional diversion choose one of these valves. However, in some cases, other types of valves can also be used for reversing and shunting as long as two or more valves are properly connected with each other.

4、带有悬浮颗粒的介质用阀门

4. Valve for medium with suspended particles

当介质中带有悬浮颗粒时，适于采用其关闭件沿密封面的滑动带有擦拭作用的阀门。如果关闭件对阀座的来回运动是竖直的，那末就可能夹持颗粒，因此这种阀门除非密封面材料可以允许嵌入颗粒，否则只适用于基本清洁的介质。球阀和旋塞阀在启闭过程中对密封面均有擦拭作用，故适宜用在带有悬浮颗粒的介质中。

When there are suspended particles in the medium, it is suitable to use the valve with wiping function by sliding its closing part along the sealing surface. If the back and forth movement of the closing member to the valve seat is vertical, particles may be clamped. Therefore, this valve is only suitable for basically clean media unless the sealing surface material allows particles to be embedded. Ball valve and plug valve can wipe the sealing surface during opening and closing, so they are suitable for medium with suspended particles.