閥門關不嚴的原因主要有下面4種情況：

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

1. 有雜質粘在密封面上，碎屑沉積在閥底部或閥瓣與閥座之間。

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. 所用介質有結晶現象。

2. The medium used has crystallization phenomenon.

3. 閥門密封面損壞，造成介質泄漏。

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

4. 閥桿與閥瓣連接不好，使閥瓣與閥座歪斜，不能緊密接觸。

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.

閥門關閉不嚴的解決辦法法：

Solution for loose valve closure:

1. 雜質卡在閥門密封面：有時閥門突然關不緊。可能是雜質卡在閥門密封面之間。這個時候，你不應該強迫它關閉。你應該把閥門開得稍微大一點，然后再把它關起來。反復嘗試，通常是可以消除的。否則，你應該再次檢查。培養基的質量也要保持清潔。

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. 閥桿螺紋生銹：當閥門通常處于開啟狀態，意外關閉時，閥桿螺紋可能生銹，可能無法緊密關閉。這種情況下，通過多次反復啟閉閥門就可以使閥門緊密關閉，而不需要對閥門進行研磨或修理。

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. 閥門密封面損壞：如果多次嘗試仍不能嚴密關閉閥門，說明密封面損壞，或腐蝕、被介質中的顆粒劃傷等，應報修。

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. 閥桿與閥瓣之間的連接不好：遇到這種情況，需要在閥桿和閥桿螺母上加潤滑油，以保證閥門啟閉靈活。應該有一個正式的維修計劃，加強對閥門的維修。

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.