The types of valves commonly used in water supply pipeline system include gate valve (screw thread, flange), stop valve (screw thread, flange), check valve (screw thread, flange), butterfly valve, etc.

(1)闸阀：可分明杆、暗杆、手动、电动、电机驱动等多种形式，闸阀具有流体阻力小，开启关闭力小，及介质可从任一方向流动等优点。但结构较为复杂，闸板密封面易被水中杂质或颗粒状物擦饰或沉积阀体底部，造成关闭不严密的缺陷。经常开启的闸阀有时会出现阀板脱落现象，使系统失去控制能力。

(1) Gate valve: it can be driven by clear rod, concealed rod, manual, electric, motor and other forms. The gate valve has the advantages of small fluid resistance, small opening and closing force, and the medium can flow from any direction. However, the structure is relatively complex, and the sealing surface of the ram is easy to be rubbed or deposited at the bottom of the valve body by impurities or particles in the water, resulting in the defect of loose closing. The frequently opened gate valve sometimes has the phenomenon of valve plate falling off, which makes the system lose control ability.

(2)截止阀：与闸阀相比具有结构简单，密封性能好，维修方便等优点，但开启关闭力稍大于闸阀，安装应注意阀体上标有箭头(水流)方向，不得装反。

(2) Stop valve: compared with gate valve, it has the advantages of simple structure, good sealing performance and convenient maintenance, but the opening and closing force is slightly greater than that of gate valve. When installing, pay attention to the direction of arrow (water flow) on the valve body and do not install it reversely.

(3)蝶阀：在给水管道上起着全开全闭作用的一种阀门。其开启关闭力较大，但阀体较小、较轻。

(3) Butterfly valve: a valve that plays the role of full opening and full closing on the water supply pipeline. Its opening and closing force is large, but the valve body is small and light.

蝶阀种类很多，根据驱动方式而分有手柄式、蜗轮蜗杆传动式、电动式、气动式等多种类型。

There are many kinds of butterfly valves, including handle type, worm gear drive type, electric type, pneumatic type and so on.

(4)止回阀：又称逆止阀，是一种只允许介质向一个方向流动的阀门，因此它具有严格的方向性。主要用于防止水倒流的管路上。

(4) Check valve: also known as check valve, it is a valve that only allows the medium to flow in one direction, so it has strict directionality. It is mainly used on the pipeline to prevent water backflow.

常用的止回阀有升降式及旋启式。升降式垂直瓣止回阀应安装在垂直管道上;升降式水平瓣止回阀和旋启式止回阀安装在水平管道上，安装时注意阀体箭头标注的方向，不得装反。

Commonly used check valves are lift type and swing type. The lifting vertical disc check valve shall be installed on the vertical pipeline; The lifting horizontal disc check valve and swing check valve are installed on the horizontal pipeline. During installation, pay attention to the direction indicated by the arrow of the valve body and do not install it reversely.