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)閘閥：可分明桿、暗桿、手動、電動、電機驅(qū)動等多種形式，閘閥具有流體阻力小，開啟關(guān)閉力小，及介質(zhì)可從任一方向流動等優(yōu)點。但結(jié)構(gòu)較為復(fù)雜，閘板密封面易被水中雜質(zhì)或顆粒狀物擦飾或沉積閥體底部，造成關(guān)閉不嚴(yán)密的缺陷。經(jīng)常開啟的閘閥有時會出現(xiàn)閥板脫落現(xiàn)象，使系統(tǒng)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)截止閥：與閘閥相比具有結(jié)構(gòu)簡單，密封性能好，維修方便等優(yōu)點，但開啟關(guān)閉力稍大于閘閥，安裝應(yīng)注意閥體上標(biāo)有箭頭(水流)方向，不得裝反。

(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)蝶閥：在給水管道上起著全開全閉作用的一種閥門。其開啟關(guān)閉力較大，但閥體較小、較輕。

(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.

蝶閥種類很多，根據(jù)驅(qū)動方式而分有手柄式、蝸輪蝸桿傳動式、電動式、氣動式等多種類型。

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

(4)止回閥：又稱逆止閥，是一種只允許介質(zhì)向一個方向流動的閥門，因此它具有嚴(yán)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.

常用的止回閥有升降式及旋啟式。升降式垂直瓣止回閥應(yīng)安裝在垂直管道上;升降式水平瓣止回閥和旋啟式止回閥安裝在水平管道上，安裝時注意閥體箭頭標(biāo)注的方向，不得裝反。

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.