A little background: A leak in a system is like a chink in the armor. It's small, but it decides the fate of the battle. Shutoff valves are our flaps, valves, taps, struggling with pressure, temperature, corrosive media. Their armor is seals. Their quality determines the reliability of the entire system.
PTFE (polytetrafluoroethylene or Teflon):
- Where to find it: in the kitchen, in space, in your plumbing system.
- Pros: not afraid of most chemicals, high temperatures (up to +250°C), "slippery", reduces friction.
- Cons: becomes brittle at low temperatures (below -200°C). Does not like heavy loads.
2. Elastomers (rubber, nitrile, viton):
- Where to find them: anywhere there is vibration, dynamic movement.
- Pros: perfectly cushioned, airtight, elastic.
- Cons: age when exposed to UV, oxygen, high temperatures. Not friendly with oils and gasoline (except for special types).
3. Graphite:
- Picture: dark, slippery tape that wraps around high-pressure pipes.
- Pros: withstands extreme temperatures (up to +450°C and higher in an inert atmosphere), chemically resistant.
- Minuses: not suitable for dynamic movement; under pressure it can caster.
4. Metal seals:
- Occur: in the most critical assemblies where even graphite gives up.
- Pros: endurance, durability, temperature and chemical resistance.
- Minuses: high price, require precision in manufacturing and installation.
How to choose? Look at the working conditions: chemistry, temperature, pressure. Check the material compatibility chart. Consider the life cycle of the system. Sometimes it is cheaper to replace a seal more often than to overpay for a "forever" material.
Conclusion: A seal is not just a piece of material. It is the heartbeat of your system. Choosing a seal material is a balance between cost, operating conditions and possible risks. The right choice today means peace of mind for years to come.
