阀门关不严的原因主要有下面4种情况：

There are four main reasons for the valve not closing tightly:

1. 有杂质粘在密封面上，碎屑沉积在阀底部或阀瓣与阀座之间。

1. Impurities stick to the sealing surface, and debris deposits at the bottom of the valve or between the valve disc and valve seat.

2. 所用介质有结晶现象。

2. The medium used has crystallization phenomenon.

3. 阀门密封面损坏，造成介质泄漏。

3. The sealing surface of the valve is damaged, causing medium leakage.

4. 阀杆与阀瓣连接不好，使阀瓣与阀座歪斜，不能紧密接触。

4. Poor connection between the valve stem and valve disc, causing the valve disc and valve seat to be skewed and unable to make close contact.

阀门关闭不严的解决办法法：

Solution for loose valve closure:

1. 杂质卡在阀门密封面：有时阀门突然关不紧。可能是杂质卡在阀门密封面之间。这个时候，你不应该强迫它关闭。你应该把阀门开得稍微大一点，然后再把它关起来。反复尝试，通常是可以消除的。否则，你应该再次检查。培养基的质量也要保持清洁。

1. Impurities getting stuck on the valve sealing surface: Sometimes the valve suddenly cannot close tightly. It is possible that impurities are stuck between the valve sealing surfaces. At this point, you should not force it to close. You should open the valve slightly larger and then close it. Repeated attempts can usually be eliminated. Otherwise, you should check again. The quality of the culture medium should also be kept clean.

2. 阀杆螺纹生锈：当阀门通常处于开启状态，意外关闭时，阀杆螺纹可能生锈，可能无法紧密关闭。这种情况下，通过多次反复启闭阀门就可以使阀门紧密关闭，而不需要对阀门进行研磨或修理。

2. Rust on valve stem threads: When the valve is usually in an open state and accidentally closed, the valve stem threads may rust and may not be able to close tightly. In this case, the valve can be tightly closed by repeatedly opening and closing it, without the need for grinding or repairing the valve.

3. 阀门密封面损坏：如果多次尝试仍不能严密关闭阀门，说明密封面损坏，或腐蚀、被介质中的颗粒划伤等，应报修。

3. Damaged valve sealing surface: If the valve cannot be tightly closed after multiple attempts, it indicates that the sealing surface is damaged, corroded, or scratched by particles in the medium, and should be reported for repair.

4. 阀杆与阀瓣之间的连接不好：遇到这种情况，需要在阀杆和阀杆螺母上加润滑油，以保证阀门启闭灵活。应该有一个正式的维修计划，加强对阀门的维修。

4. Poor connection between valve stem and valve disc: In this situation, lubricating oil needs to be added to the valve stem and valve stem nut to ensure flexible opening and closing of the valve. There should be a formal maintenance plan to strengthen valve maintenance.