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Six Commonly used Seat Material for Ball Valves

November 22, 2017

The option of a seal material for a ball valve is vital to its operation. In this post, we’re going to look at some of the featured characteristics of six commonly used alternatives for soft seals ball valves.

No.1: PTFE

When medium design condition with pressures less than 5 ksi and temperatures between -20 F and 400 F,  PTFE is an ideal seal material.; however, its temperature performance does depend on pressure. Speaking of stress, PTFE doesn’t decompress after being pressurized. Be aware that PTFE does not perform well when exposed to temperature changes greater than 167 F. One of its strengths is compound resistance yet another advantage is very low friction. It’s also fire resistant.

No.2: Glass reinforced PTFE

As used in ball valve seals is typically glass fiber, raising the pressure and temperature rating available with PTFE reinforced PTFE. Much like unreinforced PTFE, glass reinforced PTFE has very good chemical resistance with the exclusion of hydrofluoric and sexy caustics. It, too, is fire resistant and has reduced friction, although less as virgin PTFE

No.3: Stainless Steel Reinforced PTFE

There’s an alternate form of reinforced PTFE that is sometimes utilized in ball valve seals steel reinforced. This composite seal material consists of 316 stainless steel that was 50% PTFE and 50% powdered. Its temperature range is -20 F to 550 F (a little higher than virgin PTFE) plus it’s higher pressure capabilities than either glass or virgin fiber reinforced PTFE. It is fire resistant, but its coefficient of friction is PTFE

No.4: PEEK

PEEK is an option when the requirements lay out the temperature range of PTFE. PEEK works to 600 F, and is unaffected by constant exposure to steam and warm water. It is also harder, although tougher than PTFE. Its main drawback, besides its rigidity, is its brittle behavior at temperatures that are lower.

No.5: UHMW Polyethylene

UHMW Polyethyleneseems to be alternative for specialized applications, including those where there’ll be reduced to radiation exposure. Its pressure evaluation is 1.5 ksi and its temperature range is -70 F to 200 F 1500 psi -57C to 93C. UHMW Polyethylene has very good abrasion resistance.  

No.6: Chlorinated Polyether

Polyether is sometimes used as a ball valve seal material, working at temperatures around 257 F. It works in the presence of solvents and acids softening can be taken, and is resistant to more than 300 chemicals if. It doesn’t creep, and doesn’t tend to consume water.

Seal Material Future:

Seal materials is a field that is continually evolving, but these six materials seem to be the leading contenders for ball valve seal option. Their characteristics seem to the pressure and temperature operation, chemical resistance, low friction.

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