(1) Shut-off valves

这类阀门是起开闭作用的。常设于冷、热源进、出口，设备进、出口，管路分支线（包括立管）上，也可用作放水阀和放气阀。常见的关断阀有闸阀、截止阀、球阀和蝶阀等。

This kind of valve is open and close. Permanent in cold and heat sources, equipment, branch lines (including risers), can also be used as drain valves and vent valves. Common shutoff valves are gate valves, globe valves, ball valves and butterfly valves.

闸阀可分为明杆和暗杆、单闸板与双闸板、楔形闸板与平行闸板等。闸阀关闭严密性不好，大直径闸阀开启困难；沿水流方向阀体尺寸小，流动阻力小，闸阀公称直径跨度大。

Gate valves can be divided into open bar and hidden bar, single gate and double gate, wedge gate and parallel gate, etc. Gate valve closing tightness is not good, the opening of large diameter gate valve is difficult; along the direction of water flow, the size of valve body is small, flow resistance is small, and the nominal diameter span of gate valve is large.

截止阀按介质流向分直通式、直角式和直流式三种，有明杆和暗杆之分。截止阀的关闭严密性较闸阀好，阀体长，流动阻力大，最大公称直径为DN200。

Globe valves can be divided into three types according to the flow direction of medium: straight-through type, right-angle type and direct-current type, which can be divided into open rod and dark rod. The closing tightness of globe valve is better than that of gate valve. The valve body is long and the flow resistance is large. The maximum nominal diameter is DN200.

球阀的阀芯为开孔的圆球。板动阀杆使球体开孔正对管道轴线时为全开，转90°为全闭。球阀有一定的调节性能，关闭较严密。

The valve core of the ball valve is a round ball with an opening. The plate-operated valve stem makes the sphere opening fully open to the pipeline axis and turn 90 degrees to fully closed. Ball valves have a certain regulation performance and close tightly.

蝶阀的阀芯为圆形阀板，它可沿垂直管道轴线的立轴转动。当阀板平面与管子轴线一致时，为全开；闸板平面与管子轴线垂直时，为全闭。蝶阀阀体长度小，流动阻力小，比闸阀和截止阀价格高。

The valve core of the butterfly valve is a circular valve plate, which can rotate along the vertical axis of the vertical pipeline. When the valve plate plane is consistent with the axis of the sub-valve, it is fully open; when the gate plane is perpendicular to the axis of the sub-valve, it is fully closed. Butterfly valve body length is small, flow resistance is small, higher than gate valve and globe valve price.

（二）止回阀

(2) Check valves

这类阀门用于防止介质倒流，利用流体自身的动能自行开启，反向流动时自动关闭。常设于水泵的出口、疏水器出口以及其他不允许流体反向流动的地方。止回阀分旋启式、升降式和对夹式三种。对于旋启式止回阀，流体只能从左向右流动时，反向流动时自动关闭。对于升降式止回阀，流体从左向右流动时，阀芯抬起，形成通路，反向流动时阀芯被压紧到阀座上而被关闭。对于对夹式止回阀，流体从左向右流动时，阀芯被开启，形成通路，反向流动时阀芯被压紧到阀座上而被关闭，对夹式止回阀可多位安装、体积小、重量轻、结构紧凑。

This kind of valve is used to prevent medium backflow. It opens by itself using the kinetic energy of the fluid and closes automatically when it flows backwards. Permanent at pump outlet, trap outlet and other places where reverse flow of fluid is not allowed. Check valves are divided into three types: swing-open, lifting and clamping. For swing check valves, fluids can only flow from left to right, and automatically close when flowing backwards. For lift check valves, when the fluid flows from left to right, the spool rises to form a path, and when the reverse flow occurs, the spool is pressed to the seat and closed. For the clamp check valve, when the fluid flows from left to right, the valve core is opened to form a path, and when the reverse flow, the valve core is pressed to the seat and closed. For the clamp check valve, it can be installed in many places, with small volume, light weight and compact structure.

（三）调节阀

(3) Regulating valves

阀门前后压差一定，普通阀门的开度在较大范围内变化时，其流量变化不大，而到某一开度时，流量急剧变化，即调节性能不佳。调节阀可以按照信号的方向和大小，改变阀芯行程来改变阀门的阻力数，从而达到调节流量目的的阀门。调节阀分手动调节阀和自动调节阀，而手动或自动调节阀又分许多种类，其调节性能也是不同的。自动调节阀有自力式流量调节阀和自力式压差调节阀等。

When the pressure difference between front and back of the valve is constant, the flow rate of the ordinary valve changes little when the opening of the valve varies in a large range, but when a certain opening, the flow rate changes sharply, that is, the regulating performance is not good. The regulating valve can change the resistance number of the valve by changing the core stroke according to the direction and size of the signal, so as to achieve the purpose of regulating the flow rate of the valve. Regulating valves are divided into manual control valves and automatic control valves, while manual or automatic control valves are divided into many types, and their regulating performance is also different. Automatic control valves include self-operated flow control valves and self-operated differential pressure control valves.

（四）真空类

(4) Vacuum

真空类包括真空球阀、真空挡板阀、真空充气阀、气动真空阀等。其作用是在真空系统中，用来改变气流方向，调节气流量大小，切断或接通管路的真空系统元件称为真空阀门。

Vacuum categories include vacuum ball valves, vacuum baffle valves, vacuum inflation valves, pneumatic vacuum valves, etc. Its function is to change the direction of air flow, adjust the size of air flow, cut off or put through the pipeline of the vacuum system components called vacuum valves.

（五）特殊用途类

(5) Special-purpose categories

特殊用途类包括清管阀、放空阀、排污阀、排气阀、过滤器等。

Special uses include pigging valves, vent valves, sewage valves, exhaust valves, filters, etc.

排气阀是管道系统中必不可少的辅助元件，广泛应用于锅炉、空调、石油天然气、给排水管道中。往往安装在制高点或弯头等处，排除管道中多余气体、提高管道路使用效率及降低能耗。慈溪市凯迪电子是一家专业生产阀门的厂家！

Exhaust valve is an essential auxiliary component in pipeline system, which is widely used in boilers, air conditioners, oil and gas, water supply and drainage pipelines. Often installed at the elevation point or elbow, to eliminate excess gas in the pipeline, improve the efficiency of pipeline use and reduce energy consumption. Cixi Kaidi Electronics is a professional manufacturer of valves!