{"id":5108,"date":"2026-11-06T21:51:09","date_gmt":"2026-11-06T13:51:09","guid":{"rendered":"https:\/\/ptfesuppliers.com\/?p=5108"},"modified":"2026-11-06T21:51:09","modified_gmt":"2026-11-06T13:51:09","slug":"ptfe-lined-valves-information-needed-for-a-correct-specification","status":"publish","type":"post","link":"https:\/\/ptfesuppliers.com\/es\/ptfe-lined-valves-information-needed-for-a-correct-specification\/","title":{"rendered":"PTFE Lined Valves: Information Needed for a Correct Specification"},"content":{"rendered":"

Short answer:<\/strong> to specify a PTFE lined valve correctly you need seven pieces of information: valve type and size, body material and standard, liner material with temperature\/pressure class, media including slurry or solids content, actuation interface, vacuum or cycling conditions, and the inspection evidence required per valve. The liner chemistry is never the hard part — the interfaces and cycling are.<\/p>\n

Valves concentrate every lined-equipment failure mechanism into a small package: sealing faces, cycling, stems and seats that move under load. A specification that stops at “PTFE lined butterfly valve, DN80” leaves the decisions that determine service life to whoever remembers them last. Here is the information set, and why each item is on it.<\/p>\n

The specification set<\/h2>\n
    \n
  1. Type and size:<\/strong> butterfly, ball, diaphragm or plug — each lines differently, and seat behavior under cycling differs more.<\/li>\n
  2. Body and standard:<\/strong> ductile iron, WCB, CF8M; ASME\/DIN\/JIS flange drillings to match the piping.<\/li>\n
  3. Liner and class:<\/strong> PTFE or PFA, thickness, pressure\/temperature class at your<\/em> worst case — not the class-table ambient value.<\/li>\n
  4. Media detail:<\/strong> clean acid versus slurry changes seat design; trace components change permeation expectations.<\/li>\n
  5. Actuation:<\/strong> ISO pad, torque values at margin conditions, and whether cycling frequency is dozens or thousands per day — cycling, not chemistry, wears lined seats.<\/li>\n
  6. Special conditions:<\/strong> vacuum (seat suction and liner collapse risk), steam-out, thermal shock.<\/li>\n
  7. Evidence:<\/strong> spark test per liner, dimensional check of flange faces, hydro record, material certificates.<\/li>\n<\/ol>\n

    Common specification mistakes<\/h2>\n