進口止回閥工作原理
美國歐可止回閥(One-way valve)：止回閥又稱單向閥或逆止閥，其作用是防止管路中的介質倒流。水泵吸水關的底閥也屬于止回閥類。止回閥按結構劃分，可分為升降式止回閥、旋啟式止回閥和蝶式止回閥三種。升降式止回閥可分為立式和臥式兩種。旋啟式止回閥分為單瓣式、雙瓣式和多瓣式三種。蝶式止回閥為直通式、以上幾種止回閥在連接形式上可分為螺紋連接、法蘭連接和焊接三種。 進口止回閥有二種體蓋連接設計形式：第一種是體蓋螺栓連接鍛鋼止回閥，按這種連接形式設計的閥門，其閥體與閥蓋用螺栓連接，纏繞式墊片密封，優點是便于維修；第二種體蓋全焊密封鍛鋼止回閥，按這種連接形式設計的閥門，其閥體與閥蓋用螺蚊連接，全焊密封，優點是無泄漏。
進口止回閥形式種類
止回閥按結構劃分，可分為升降式止回閥、旋啟式止回閥和蝶式止回閥三種。升降式止回閥可分為立式和臥式兩種。旋啟式止回閥分為單瓣式、雙瓣式和多瓣式三種。蝶式止回閥為直通式、以上幾種止回閥在連接形式上可分為螺紋連接、法蘭連接和焊接三種。
1、升降式止回閥的結構一般與截止閥相似，其閥瓣沿著通道中以線作升降運動，動作可靠，但流體阻力較大，適用于輕小口徑的場合。升降式止回閥可直通式和立式兩種。直通式升降止回閥一般只能安裝在水平管路，而立式升降止回閥一般就安裝在垂直管路。
2、旋啟式止回閥的閥瓣繞轉軸作旋轉運動。其流體阻力一般小于升降式止回閥，它適用于較大口徑的場合。旋啟式止回閥根據閥瓣的數目可分為單瓣旋啟式、雙瓣旋啟式及多瓣旋啟式三種。單瓣旋啟式止回閥一般適用于中等口徑的場合。大口徑管路選用單瓣旋啟式止回閥時，為減少水錘壓力，最好采用能減小水錘壓力的緩閉止回閥。雙瓣旋啟式止回閥適用于大中口徑管路。對夾雙瓣旋啟式止回閥結構小、重量輕，是一種發展較快的止回閥；多瓣旋啟式止回閥適用于大口徑管路。
3、隔膜式止回閥有多種結構形式，均采用隔膜作為啟閉件，由于其防水錘性能好，結構簡單，成本低，近年來發展較快。但隔膜式止回閥的使用溫度和壓力受到隔膜材料的限制。
4、球型污水止回閥：閥體采用全通道結構，具有流量大、阻力小之優點。采用圓球做閥瓣，適用于高粘度、有懸浮物的工業及生活污水管網
5、蝶式止回閥的結構類似于蝶閥。其結構簡單、流阻較小，水錘壓力亦較小。
進口止回閥主要特點
1、結構長度短，其結構長度只有傳統法蘭止回閥的1/4~1/8
2、體積小、重量輕、其重量只有傳統法蘭止回閥的1/4~1/20
3、閥瓣關閉快速，水錘壓力小
4、水平或垂直管道均可使用，安裝方便
5、流道通暢、流體阻力小
6、動作靈敏、密封性能好
7、閥瓣行程短、關閥沖擊力小
8、整體結構、簡單緊湊、造型美觀
9、使用壽命長、可靠性高
let check valve working principle
The United States of America Ou check valve ( One-way valve ): check valve also known as a one-way valve or check valve, its role is to prevent the medium in pipeline flow. Pump water off the end of the valve is also a non-return valve. Check valve according to its structure, can be divided into lift check valve, swing check valve butterfly check valve three. Lift check valve can be divided into two kinds of vertical and horizontal. Swing check valve is divided into a single type, double valve and valve type three. Butterfly type check valve for straight-through, above a few kinds of check valve in the form of connection can be divided into the thread, flange connection and welding three. Inlet check valve body cover to connect the design has two forms: the first is a body cover bolt connection forged steel check valve, according to this form of connection of the valve, the valve body with the valve cover bolt connection, spiral wound gasket seal, the advantage of easy repair; the second body cover all welded seal forged steel check valve, according to this form of connection of the valve, the valve body with the valve cover with the screw thread connection, all-welded seal, the advantage of no leakage.
Inlet check valve forms
Check valve according to its structure, can be divided into lift check valve, swing check valve butterfly check valve three. Lift check valve can be divided into two kinds of vertical and horizontal. Swing check valve is divided into a single type, double valve and valve type three. Butterfly type check valve for straight-through, above a few kinds of check valve in the form of connection can be divided into the thread, flange connection and welding three.
In 1, the lift check valve and stop valve structure is generally similar, the valve flap along the channel line to make lifting motion, reliable action, but the fluid resistance, suitable for light and small caliber of the occasion. Lift check valve can be straight and vertical two. Straight through type lifting check valve in general can only be installed in horizontal pipeline, but the vertical lift check valve is usually installed in a vertical pipe.
In 2, swing check valve to rotate around the rotating shaft. The fluid resistance is generally smaller than the lift check valve, which applies to a larger diameter. Swing check valve according to the valve flap can be divided into the number of single swing, double valve swing and multiple valve swing three. Single swing check valves are generally applicable to the medium-calibre occasions. Large diameter pipeline with single swing check valve, to reduce water hammer pressure, the best use can reduce water hammer pressure slow close check valve. Double valve swing check valve for large diameter pipeline. Clip on double valve swing check valve structure of small, light weight, is a rapid development of the check valve; valve swing check valve for large diameter pipeline.
In 3, a diaphragm type check valve has various structural forms, are used as a hoist pieces divide, water hammer because of its good performance, simple structure, low cost, rapid development in recent years. But diaphragm type check valve with temperature and pressure by the diaphragm material.
In 4, ball type sewage check valve : body by the channel structure, with large flow, little resistance of the advantages of. The ball valve valve, suitable for high viscosity, suspended and industrial and domestic sewage pipe network
5, butterfly check valve structure is similar to a butterfly valve. It has the advantages of simple structure, small flow resistance, the water hammer pressure is small.
Inlet check valves major features
1, structure of short length, the length of its structure only traditional flange check valve 1/4~1/8
In 2, small volume, light weight, its weight is only the traditional flange check valve1/4~1/20
In 3, the valve closed quickly, the water hammer pressure small
In 4, a horizontal or vertical pipe can be used, easy installation
5, flow passage, the fluid resistance is small
6, flexible action, good sealing performance
In 7, the valve closing valve of short stroke, small impact force
In 8, the overall structure, has simple and compact structure, handsome in appearance
In 9, long service life, high reliability
