【摘要】本文对各类常见阀门的性能、安装与工作原理做简要比较
一、阀门的选择及设置部位：
（一）给水管道上使用的阀门，一般按下列原则选择：
1、管径不大于50mm时，宜采用截止阀，管径大于50mm时采用闸阀、蝶阀
2、需调节流量、水压时宜采用调节阀、截止阀
3、要求水流阻力小的部位（如水泵吸水管上），宜采用闸板阀
4、水流需双向流动的管段上应采用闸阀、蝶阀，不得使用截止阀
5、安装空间小的部位宜采用蝶阀、球阀
6. On pipe sections that are frequently opened and closed, stop valves should be used
7. Multi-function valves should be used on the water pump outlet pipe with larger diameter
(2) Valves shall be provided at the following parts of the water supply pipeline:
1、居住小区给水管道从市政给水管道的引入管段上
2、居住小区室外环状管网的节点处，应按分隔要求设置。环状管段过长时，宜设置分段阀门
3、从居住小区给水干管上接出的支管起端或接户管起端
4、入户管、水表和各分支立管（立管底部、垂直环形管网立管的上、下端部）
5、环状管网的分干管、贯通枝状管网的连接管
6、室内给水管道向住户、公用卫生间等接出的配水管起端，配水支管上配水点在3个及3个以上时设置
7、水泵的出水管，自灌式水泵的吸水泵
8、水箱的进、出水管、泄水管
9、设备（如加热器、冷却塔等）的进水补水管
10、卫生器具（如大、小便器、洗脸盆、淋浴器等）的配水管
11、某些附件，如自动排气阀、泄压阀、水锤消除器、压力表、洒水栓等前、减压阀与倒流防止器的前后等
12、给水管网的最低处宜设置泄水阀
（三）止回阀一般应按其安装部位、阀前水压、关闭后的密闭性能要求和关闭时引发的水锤大小等因素来选择
1、阀前水压小时，宜选用旋启式、球式和梭式止回阀
2、关闭后的密闭性能要求严密时，宜选用有关闭弹簧的止回阀
3、要求削弱关闭水锤时，宜选用速闭消声止回阀或有阻尼装置的缓闭止回阀
4. The valve break or spool of the check valve should be able to close by itself under the action of gravity or spring force.
(4) Check valves shall be provided on the following sections of the water supply pipeline:
On the inlet pipe; on the inlet pipe of a closed water heater or water-consuming equipment; on the outlet pipe of a water pump; on the outlet pipe section of a water tank, water tower, and highland pool where the inlet and outlet pipes share the same pipe.
注：装有管道倒流防止器的管段，不需在装止回阀。
(五)给水管道的下列部位应设置排气装置：
1、间歇性使用的给水管网，其管网末端和最高点应设置自动排气阀
2、给水管网有明显起伏积聚空气的管段，已在该段的峰点设自动排气阀或手动阀门排气
3、气压给水装置，当采用自动补气式气压水罐时，其配水管网的最高点应设自动排气阀
二、各种阀门的优缺点：
1、闸阀：闸阀是指关闭件（闸板）沿通道轴线的垂直方向移动的阀门，在管路上主要作为切断介质用，即全开或全关使用。一般，闸阀不可作为调节流量使用。它可以适用低温压也可以适用于高温高压，并可根据阀门的不同材质。但闸阀一般不用于输送泥浆等介质的管路中
优点：
①流体阻力小；
②启、闭所需力矩较小；
③可以使用在介质向两方向流动的环网管路上，也就是说介质的流向不受限制；
④全开时，密封面受工作介质的冲蚀比截止阀小；
⑤形体结构比较简单，制造工艺性较好；
④ The structure length is relatively short.
Disadvantages:
① The overall size and opening height are large, and the installation space required is also large;
② During the opening and closing process, people rub against the sealing surface, causing large friction, and even easily cause scratches at high temperatures;
③ Generally, gate valves have two sealing surfaces, which adds some difficulties to processing, grinding and maintenance;
④启闭时间长。
2、蝶阀：蝶阀是用圆盘式启闭件往复回转90°左右来开启、关闭和调节流体通道的一种阀门。
优点：
①结构简单，体积小，重量轻，耗材省，别用于大口径阀门中；
②启闭迅速，流阻小；
③可用于带悬浮固体颗粒的介质，依据密封面的强度也可用于粉状和颗粒状介质。可适用于通风除尘管路的双向启闭及调节，广泛用于冶金、轻工、电力、石油化工系统的煤气管道及水道等。
Disadvantages:
①流量调节范围不大，当开启达30%时，流量就将进95%以上；
②由于蝶阀的结构和密封材料的限制，不宜用于高温、高压的管路系统中。一般工作温度在300℃以下，PN40以下；
③密封性能相对于球阀、截止阀较差，故用于密封要求不是很高的地方。
3, ball valve:It evolved from a plug valve. Its opening and closing part is a ball, which uses the ball to rotate 90° around the axis of the valve stem to achieve opening and closing purposes. Ball valves are mainly used to cut off, distribute and change the flow direction of media on pipelines. Ball valves designed with V-shaped openings also have good flow regulation functions.
优点：
① has the lowest flow resistance (actually 0);
② Because it will not get stuck during work (when there is no lubricant), it can be reliably used in corrosive media and low-boiling liquids;
③ Complete sealing can be achieved within a large pressure and temperature range;
④可实现快速启闭，某些结构的启闭时间仅为0.05~0.1s，以保证能用于试验台的自动化系统中。快速启闭阀门时，操作无冲击；
⑤球形关闭件能在边界位置上自动定位；
⑥工作介质在双面上密封可靠；
⑦在全开和全闭时，球体和阀座的密封面与介质隔离，因此高速通过阀门的介质不会引起密封面的侵蚀；
⑧结构紧凑、重量轻，可以认为它是用于低温介质系统的最合理的阀门结构；
⑨阀体对称，尤其是焊接阀体结构，能很好地承受来自管道的应力；
⑩关闭件能承受关闭时的高压差。⑾全焊接阀体的球阀，可以直埋于地下，使阀门内件不受浸蚀，最高使用寿命可达30年，是石油、天然气管线最理想的阀门。
Disadvantages:
① Because the main seat sealing ring material of ball valves is polytetrafluoroethylene, it is inert to almost all chemical substances, and has a small friction coefficient, stable performance, is not easy to age, wide temperature range and excellent sealing performance. Comprehensive characteristics. However, the physical characteristics of PTFE, including high expansion coefficient, sensitivity to cold flow and poor heat conductivity, require that seat seals be designed around these characteristics. Therefore, when the sealing material hardens, the reliability of the seal is destroyed. Moreover, polytetrafluoroethylene has a low temperature resistance level and can only be used below 180 ° C. Above this temperature, the sealing material will age. When considering long-term use, it is generally not used at 120 ° C.
② Its adjustment performance is worse than that of the stop valve, especially the pneumatic valve (or electric valve).
4, stop valve:Refers to a valve whose closure member (disc) moves along the centerline of the seat. According to this movement of the valve flap, the change in the valve seat opening is directly proportional to the stroke of the valve flap. Because the valve stem opening or closing stroke is relatively short and has a very reliable shut-off function, and because the change of the valve seat port is directly proportional to the stroke of the valve flap, it is very suitable for adjusting flow. Therefore, this type of valve is very useful for shut-off or regulation as well as throttling.
优点：
① During the opening and closing process, the friction between the valve disc and the sealing surface of the valve body is smaller than that of the gate valve, so it is wear-resistant.
②开启高度一般仅为阀座通道的1/4，因此比闸阀小得多；
③ There is usually only one sealing surface on the valve body and the valve disc, so the manufacturing process is relatively good and it is easy to maintain;
④ Since its filler is generally a mixture of asbestos and graphite, the temperature resistance level is high. General steam valves use stop valves.
Disadvantages:
① Due to the change in the flow direction of the medium through the valve, the minimum flow resistance of the stop valve is also higher than that of most other types of valves;
② Due to the long stroke, the opening speed is slower than that of the ball valve.
5, stopcock valve:是指关闭件成柱塞形的旋转阀，通过90°的旋转使阀塞上的通道口与阀体上的通道口相通或分开，实现开启或关闭的一种阀门。阀塞的形状可成圆柱形或圆锥形。其原理与球阀基本相似，球阀是在旋塞阀的基础上发展起来的，其主要用于油田开采，同时也用于石油化工。
6、安全阀：是指在受压容器、设备或管路上，作为超压保护装置。当设备、容器或管路内的压力升高超过允许值时，阀门自动开启，继而全量排放，以防止设备、容器或管路和压力继续升高；当压力降低到规定值时，阀门应自动及时关闭，从而保护设备、容器或管路的安全运行。
7、蒸汽疏水阀：在输送蒸汽、压缩空气等介质中，会有一些冷凝水形成，为了保证装置的工作效率和安全运转，就应及时排放这些无用且有害的介质，以保证装置的消耗和使用。它有以下作用：①能迅速排除产生的凝结水；②防止蒸汽泄露；③排除空气及其他不凝性气体。
8、减压阀：是通过调节，将进口压力减至某一需要的出口压力，并依靠介质本身的能量，使出口压力自动保持稳定的阀门。
9、止回阀：Also known as backflow valve, check valve, back pressure valve and one-way valve. These valves are automatically opened and closed by the force generated by the flow of the medium itself in the pipeline and are an automatic valve. Check valves are used in pipeline systems. Their main role is to prevent backflow of media, reverse rotation of pumps and driving motors, and release of container media. Check valves can also be used on pipelines that supply auxiliary systems where the pressure may rise to exceed the system pressure. They can be mainly divided into swing type (rotating according to the center of gravity) and lifting type (moving along the axis).
