進口止回閥的分類以及如何選型
進口止回閥的作用是只允許介質(zhì)向一個方向流動，而且阻止方向流動。通常這種閥門是自動工作的，在一個方向流動的流體壓力作用下，閥瓣打開；流體反方向流動時，由流體壓力和閥瓣的自重合閥瓣作用于閥座，從而切斷流動。
止回閥包括旋啟式止回閥和升降式止回閥。
進口旋啟式止回閥有一介鉸鏈機構(gòu)，還有一個像門一樣的閥瓣自由地靠在傾斜的閥座表面上。 為了確保閥瓣每次都能到達閥座面的合適位置，閥瓣設(shè)計在鉸鏈機構(gòu)，以便閥瓣具有足夠有旋啟空間，并使閥瓣真正的、全面的與閥座接觸。閥瓣可以全部用金屬制成，也可以在金屬上鑲嵌皮革、橡膠、或者采用合成覆蓋面，這取決于使用性能的要求。旋啟式止回閥在完全打開的狀況下，流體壓力幾乎不受阻礙，因此通過閥門的壓力降相對較小。
進口升降式止回閥的閥瓣座落位于閥體上閥座密封面上。 此閥門除了閥瓣可以自由地升降之外，其余部分如同截止閥一樣，流體壓力使閥瓣從閥座密封面上抬起，介質(zhì)回流導(dǎo)致閥瓣回落到閥座上，并切斷流動。根據(jù)使用條件，閥瓣可以是全金屬結(jié)構(gòu)，也可以是在閥瓣架上鑲嵌橡膠墊或橡膠環(huán)的形式。像截止閥一樣，流體通過升降式止回閥的通道也是狹窄的，因此通過升降式止回閥的壓力降比旋啟式止回閥大些，而且旋啟式止回閥的流量受到的限制很少。
How to choose to prevent the backflow valve media This type of valve is the role of the media to only allow flow in one direction, but also to prevent the direction of flow. Normally this valve works automatically, in a direction of fluid flow under pressure, the valve opens; the opposite direction of fluid flow, fluid pressure and valve from the self-overlap effect on the valve seat, thereby cutting off flow. Which belongs to this type of check valve valve, which includes the swing check valve and lift check valves. Swing check valve with ordinary hinge, there is a door the same as freedom against the valve seat surface tilt. To ensure that every time the valve seat surface to reach the appropriate position, the valve flap hinge design, the valve has to have enough swing space, and a real disc, full with the valve seat. Valve can all be made of metal, can also be embedded in the metal on leather, rubber, or synthetic cover, depending on performance requirements. Swing check valve in the fully open position, the fluid pressure is almost free of obstruction, so the pressure drop through the valve is relatively small. Valve lift check valve located in the valve body seat sealing surface. In addition to this valve is free to lift the valve, the valve the same as the rest, the fluid pressure to the valve lift from the valve seat sealing surface, return media led down to the valve seat, and cut off the flow. Depending on conditions, the valve can be all metal construction, it can be rack mounted in the valve rubber or rubber ring form. The same as the cut-off valve, lift check valve fluid through the channel is narrow, so by the lift check valve pressure drop than the swing check valve bigger, and swing check valve flow restrictions very little.