Industrial High Pressure Valves need to choose different sealing forms and materials according to different pressure grades and working conditions. Complete valve sealing generally includes four aspects:
Seat Sealing: High-pressure valves generally use metal seals, also known as hard seals, that is, seats and valve discs (closures) are metal; but high-pressure soft-seal valves (such as ball valves, cock valves, butterfly valves) are made of non-metallic materials, such as PTFE, NBR, PPL, etc.
2. Stem packing seal: flexible graphite ring is generally used, stainless steel wire is added to increase strength inside, and some valves are made of non-metal materials such as PTFE, RPTFE, NBR, PPL, etc. when the temperature is not high.
3. Midway Seal between Valve Body and Cover: Generally there is flange structure: metal wound gasket, metal coated graphite gasket, RTJ metal seal ring. The other is pressure self-sealing structure (PSB). There are two kinds of sealing rings: one is metal + graphite ring material, the other is stainless steel such as F316.
4. Sealing between valve body and transfer pipeline: There are flange structures in general: metal wound gaskets, metal coated graphite gaskets, metal RTJ seals; the other is welded structure (BW), that is, the two ends of the valve are directly welded in the pipeline.