1.Assist spare parts

- Lack of initial pressure 
- Uneven bolt load 
- The thread on the bolt is damaged 
- Faulty bolt 
- The flange face is not aligned

2.Gasket materials

- Reuse of old gaskets 
- Incompatible with media 
- Not suitable for working and mining conditions 
- Use mismatched compounds 
- Improper size 
- High leakage rate


3.The design factors

- Underload of bolt 
- Excess load 
- Wrong selection of flange and bolt

4.The flange

- Surface damage 

- Uneven working surface