止回閥按結構原理可分為以下幾類，適用場景因介質特性、結構差異而不同。

　　Check valves can be divided into the following categories based on their structural principles, and their applicable scenarios vary depending on the characteristics of the medium and structural differences.

　　升降式止回閥升降式止回閥是通過閥座的上升和下降來實現止回功能，當流體流向反轉時，閥座會被流體沖擊使其關閉閥門，防止流體倒流。結構：沿閥體垂直中心線上下滑動，類似截止閥結構閥瓣，閥瓣沿軸向升降啟閉，流道狹窄，阻力大，密封性能較好。適用場合：僅適用于清潔介質（如成品油、水、蒸汽）、小口徑管道（DN≤200），且安裝在水平管道。

　　Lift check valve Lift check valve achieves the check function through the rise and fall of the valve seat. When the fluid flow direction is reversed, the valve seat will be impacted by the fluid to close the valve, preventing fluid backflow. Structure: Sliding along the vertical center line of the valve body, similar to a globe valve structure valve disc, the valve disc rises and falls along the axial direction, with narrow flow channels, high resistance, and good sealing performance. Applicable occasions: Only suitable for cleaning media (such as finished oil, water, steam), small-diameter pipelines (DN ≤ 200), and installed in horizontal pipelines.

　　旋啟式止回閥

　　Swing check valve

　　閥瓣為圓盤狀，繞閥體內部的固定轉軸做旋轉啟閉（類似門繞合頁轉動）。結構：閥瓣繞軸旋轉啟閉，流道寬敞，阻力小，單瓣/雙瓣/多瓣設計適應不同口徑。適用場合：適用于大口徑管道（DN≥200）、介質含少量雜質的場景（如工業廢水、冷卻水系），可水平或垂直安裝（流向向上）。

　　The valve disc is disc-shaped and rotates around a fixed axis inside the valve body to open and close (similar to a door rotating around a hinge). Structure: The valve disc rotates around the axis to open and close, with a spacious flow channel and low resistance. The single/double/multi disc design is suitable for different diameters. Applicable occasions: Suitable for large-diameter pipelines (DN ≥ 200) and media containing small amounts of impurities (such as industrial wastewater, cooling water systems), can be installed horizontally or vertically (with upward flow direction).

　　蝶式止回閥結構：閥瓣為圓盤狀（類似蝶閥），繞閥體偏心軸旋轉啟閉；結構緊湊，體積小，重量輕，流道呈流線型；適合大口徑低壓管道。適用場合：適用于DN≥300的低壓管道（如城市污水干管、污水處理廠總排管），可處理含懸浮物的污水，但需避免高黏度介質黏附閥瓣。

　　Butterfly check valve structure: The valve disc is disc-shaped (similar to a butterfly valve) and rotates around the eccentric axis of the valve body to open and close; Compact structure, small volume, light weight, streamlined flow channel; Suitable for large-diameter low-pressure pipelines. Applicable occasions: Suitable for low-pressure pipelines with DN ≥ 300 (such as urban sewage main pipes and sewage treatment plant main discharge pipes), which can treat sewage containing suspended solids, but high viscosity media should be avoided from adhering to valve discs.

　　球形止回閥結構：閥瓣為實心/空心球體，依靠介質壓力推動球體沿流道滾動實現啟閉；閥體內部有導向槽，限制球體僅沿軸向移動；阻力極小，抗堵塞能力強。適用場合：適用于含顆粒、纖維的介質（如污水提升泵出口、農業灌溉），低壓大流量場景，不易被毛發、泥沙卡阻。

　　Spherical check valve structure: The valve disc is a solid/hollow sphere, which relies on the pressure of the medium to push the sphere to roll along the flow channel to achieve opening and closing; There is a guide groove inside the valve body, which restricts the ball from moving only along the axial direction; Extremely low resistance and strong anti blocking ability. Applicable occasions: Suitable for media containing particles and fibers (such as sewage lift pump outlet, agricultural irrigation), low-pressure and high flow scenarios, not easily blocked by hair and sediment.

　　活塞式止回閥

　　Piston check valve

　　結構：閥瓣為活塞狀，沿閥體內部的精密導向孔做軸向滑動；通常內置彈簧（輔助關閉），部分無彈簧（依賴介質反向壓力）。適用場合：僅用于清潔介質（如自來水、成品油等），嚴禁用于污水系統。

　　Structure: The valve disc is piston shaped and slides axially along the precision guide hole inside the valve body; Usually equipped with a built-in spring (to assist in closing), some without a spring (relying on the reverse pressure of the medium). Applicable occasions: Only used for cleaning media (such as tap water, refined oil, etc.), strictly prohibited for use in sewage systems.

　　軸流式止回閥軸流式止回閥，是通過流體壓力差與彈簧力協同作用實現閥瓣的軸向啟閉，正向流動時靜壓差推動閥瓣開啟，反向流動或壓力不足時彈簧力促使閥瓣快速關閉以防止逆流。結構：軸流式止回閥主要由閥體、閥座、閥瓣、彈簧、導向桿、導向套及導流罩等零部件組成，進口介質壓力推動閥瓣開啟，閥瓣進口側表面為圓弧形；停泵后，進口壓力逐漸降低，在彈簧作用下，閥瓣關閉，防止倒流；閥瓣關閉時平穩、減震、消聲、減小水擊。適用場合：壓縮機出口、大功率泵出口（特別是高壓水泵和油泵）、油氣輸送管道以及電站給水系統等。

　　Axial flow check valve is a type of valve that achieves axial opening and closing of the valve disc through the synergistic effect of fluid pressure difference and spring force. When flowing forward, the static pressure difference pushes the valve disc to open, and when flowing backward or under pressure, the spring force quickly closes the valve disc to prevent backflow. Structure: Axial flow check valve is mainly composed of valve body, valve seat, valve disc, spring, guide rod, guide sleeve, and guide cover. The inlet medium pressure pushes the valve disc to open, and the inlet surface of the valve disc is arc-shaped; After stopping the pump, the inlet pressure gradually decreases, and under the action of the spring, the valve disc closes to prevent backflow; When the valve disc is closed, it is smooth, shock-absorbing, soundproof, and reduces water hammer. Applicable occasions: compressor outlet, high-power pump outlet (especially high-pressure water pump and oil pump), oil and gas transmission pipeline, and power plant water supply system, etc.

　　橡膠瓣止回閥

　　Rubber flap check valve

　　結構：閥瓣為橡膠材質，彈性好，密封面不易磨損，流道通暢。適用場合：適用于污水、雨水等含雜質介質，中小口徑管道（DN50~DN300），抗堵塞和耐腐蝕性能優于金屬瓣。

　　Structure: The valve disc is made of rubber material, with good elasticity, the sealing surface is not easily worn, and the flow channel is smooth. Applicable occasions: Suitable for media containing impurities such as sewage and rainwater, small and medium-sized pipelines (DN50~DN300), with better resistance to blockage and corrosion than metal plates.

　　梭式止回閥（軸流式）梭式止回閥（又稱“滑塊式止回閥”“梭閥”）屬于升降式止回閥的特殊衍生類型，其核心設計是將傳統“圓盤/圓柱閥瓣”替換為“梭形滑塊”，結構與性能具有顯著特殊性。結構：閥瓣為梭形（兩端尖、中間粗）滑塊；閥體內部有對稱的流線型導向腔，滑塊僅能沿軸向做往復滑動（類似“梭子在織布機中移動”）；部分型號內置輕量化彈簧（輔助滑塊復位，減少關閉滯后），流道全程無死角、無突出部件。性能特點：①壓力損失極小：梭形滑塊與流線型流道匹配，介質流動阻力遠低于旋啟式、蝶式。關閉速度快：②滑塊滑動阻力小，且對稱結構受力均勻，反向介質壓力可瞬間推動滑塊密封，水錘風險低。③抗雜質能力強：流道無轉軸、凹槽等易卡堵結構，少量雜質可隨介質排出，不易卡住滑塊。④安裝靈活：可水平或垂直安裝（滑塊重力影響小），適用角度范圍廣。

　　Shuttle type check valve (axial flow type) Shuttle type check valve (also known as "slide type check valve" or "shuttle valve") belongs to a special derivative type of lift type check valve. Its core design is to replace the traditional "disc/cylindrical valve disc" with a "shuttle shaped slide block", and its structure and performance have significant characteristics. Structure: The valve disc is a shuttle shaped (pointed at both ends, thick in the middle) slider; There is a symmetrical streamlined guide cavity inside the valve body, and the slider can only slide back and forth along the axial direction (similar to "shuttle moving in a loom"); Some models are equipped with lightweight springs (to assist in resetting the slider and reduce closing hysteresis), and the entire flow path has no dead corners or protruding parts. Performance characteristics: ① Minimal pressure loss: The shuttle shaped slider matches the streamlined flow channel, and the medium flow resistance is much lower than that of the rotary and butterfly types. Fast closing speed: ② The sliding resistance of the slider is small, and the symmetrical structure is uniformly stressed. The reverse medium pressure can instantly push the slider seal, and the risk of water hammer is low. ③ Strong anti impurity ability: The flow channel has no shaft, groove or other easily clogged structures, and a small amount of impurities can be discharged with the medium, making it less likely to get stuck in the slider. ④ Flexible installation: can be installed horizontally or vertically (with minimal influence of slider gravity), suitable for a wide range of angles.