Valve stem packing elastic seal, stem use disc spring, compression spring to achieve packing long-term seal

Valve stem seal generally used packing seal, packing by compaction to achieve sealing. Common fillers are graphite, PTFE V-rings, etc.
1. Add belleville spring at packing gland to realize continuous sealing
As shown in No. 7 of the following figure, 2 belleville spring are added above the packing gland.