Check valves belong to this type of valve, including swing check valves and Kunshan Lianggong valve lift check valves. The Kunshan Lianggong valve swing check valve has a hinge mechanism and a gate like valve disc that freely rests on the tilted valve seat surface. In order to ensure that the valve disc can reach the appropriate position on the valve seat surface every time, the valve disc is designed in a hinge mechanism, so that the valve disc has sufficient swing space and truly and comprehensively contacts the valve seat. The valve disc can be made entirely of metal, or it can be embedded with leather, rubber, or a synthetic cover on the metal, depending on the performance requirements. When the swing check valve is fully open, the fluid pressure is almost unobstructed, so the pressure drop through the valve is relatively small. The disc seat of the lift check valve is located on the sealing surface of the valve seat on the valve body. Except for the free lifting and lowering of the valve disc, the rest of this valve is like a globe valve. Fluid pressure lifts the valve disc from the sealing surface of the valve seat, and the medium backflow causes the valve disc to fall back onto the valve seat, cutting off flow. According to the usage conditions, the valve disc can be an all metal structure, or it can be in the form of embedded rubber pads or rings on the valve disc holder. Like globe valves, the passage of fluid through lift check valves is also narrow, so the pressure drop through lift check valves is greater than that of swing check valves, and the flow rate of swing check valves is limited very little.

止回閥常見(jiàn)故障及處理方法常見(jiàn)故障有：

Common faults and handling methods of check valves include:

①閥瓣打碎

① Broken valve disc

②介質(zhì)倒流。

② Media backflow.

引起閥瓣打碎的原因是：

The cause of valve disc breakage is:

止回閥前后介質(zhì)壓力處于接近平衡而又互相“拉鋸”的狀態(tài)，昆山良工閥門(mén)閥瓣經(jīng)常與閥座拍打，某些脆性材料(如鑄鐵、黃銅等)做成的閥瓣就被打碎。預(yù)防的辦法是采用閥瓣為韌性材料的止回閥。

The medium pressure before and after the check valve is in a state of close balance and mutual "sawing". The valve disc of Kunshan Lianggong valve often beats against the valve seat, and the valve disc made of some brittle materials (such as cast iron, brass, etc.) is broken. The preventive method is to use a check valve with a resilient disc material.

介質(zhì)倒流的原因有：

The reasons for media backflow include:

①密封面破壞

① Damaged sealing surface

②夾入雜質(zhì)。

② Inclusion of impurities.

修復(fù)密封面和清洗雜質(zhì)，就能防止倒流。

Repairing the sealing surface and cleaning impurities can prevent backflow.