What Seals for Industrial High Pressure Valves
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:
1.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.