The one-piece body full PTFE lined butterfly valve features a vulcanized PTFE seat permanently bonded to the valve body, eliminating the risk of liner delamination under vacuum and thermal cycling. With zero exposed metal in the flow path, this valve delivers zero-leakage shutoff and full corrosion resistance across the entire wetted surface — making it the definitive choice for aggressive chemical, pharmaceutical, and food-grade applications where standard lined valves fail.
Conventional PTFE lined butterfly valves use a loose or mechanically retained PTFE liner that sits inside the body. Under vacuum conditions, thermal expansion differentials, or repeated cycling, the liner can pull away from the body wall — creating a cavitation zone behind the liner where process media can accumulate and corrode the metal body from the inside out.
The one-piece body design further enhances structural integrity. Unlike split-body or two-piece designs that rely on gaskets and fasteners at the body joint, the one-piece casting has no mid-body seam — reducing potential leak paths to the stem passages only, which are sealed by a PTFE-enveloped stem seal and secondary O-ring.
| Feature | Technical Benefit |
|---|---|
| One-piece investment-cast body | No body joint gaskets; eliminates mid-body leak path. Superior structural rigidity under pipe loading. |
| Full PTFE/PFA lining (min. 6 mm thick) | Complete isolation of metal body from process media. Resists strong acids (HCl, H₂SO₄, HNO₃), alkalis, solvents, and oxidizing agents. |
| Vulcanized PTFE seat bonded to body | Permanent chemical bond prevents liner lift-off under full vacuum (-1 bar gauge). Survives thermal cycling from -29°C to +180°C without delamination. |
| PTFE-encapsulated disc | Zero metal exposure at the disc surface. Disc hub is fully encapsulated; no pitting corrosion at the stem-to-disc connection. |
| Self-adjusting stem seal | PTFE V-ring pack with Belleville spring live-loading compensates for wear and thermal expansion without manual retorquing. |
| ISO 5211 top flange | Direct mounting of pneumatic, electric, or hydraulic actuators. Compatible with NAMUR solenoid and positioner interfaces. |
| Anti-blowout stem | Stem shoulder design retains the shaft under full rated pressure even if the external retainer is removed. Compliant with API 609. |
| Parameter | Specification |
|---|---|
| Nominal Diameter | DN50, DN65, DN80, DN100, DN125, DN150, DN200, DN250, DN300, DN350, DN400 |
| Face-to-Face | Per ISO 5752 Series 20 (short pattern) / API 609 Category A |
| Pressure Rating | 10 Bar |
| Body Style | Wafer Lug |
| Seat Test | Zero visible leakage per EN 12266-1 Rate A / API 598 |
| Vacuum Rating | Full vacuum (-1 bar gauge) at ambient temperature |
| Operating Temperature | -29°C to +180°C |
| Top Flange | ISO 5211 |
| Component | Material | Standard |
|---|---|---|
| Body | Investment-cast ductile iron / WCB carbon steel / CF8M stainless steel | ASTM A395 / A216 / A351 |
| Body Lining | PTFE or PFA | ASTM D4894 / D3307 |
| Disc | Ductile iron / CF8M with full PTFE/PFA encapsulation | — |
| Stem | SS316 / 17-4PH (precipitation-hardened) | ASTM A276 / A564 / B574 |
| Stem Seal | PTFE V-ring set with FKM O-ring backup | — |
| Seat | PTFE vulcanized to body | ASTM D4894 |
The full PTFE lining and vulcanized seat provide near-universal chemical resistance. PTFE (polytetrafluoroethylene) is inert to virtually all industrial chemicals except molten alkali metals and elemental fluorine at elevated temperatures. Key resistant media include:
| Industry | Application |
|---|---|
| Chemical Processing | Acid transfer lines, reactor feed and discharge, corrosive solvent handling |
| Pharmaceutical | WFI (water for injection) loops, CIP/SIP systems, sterile media isolation |
| Food & Beverage | Edible oil processing, CIP return lines, sugar refining |
| Water Treatment | Chlorine dosing, hypochlorite lines, acid/alkali dosing skids |
| Pulp & Paper | Chlorine dioxide bleaching, black liquor, white liquor handling |
| Steel Pickling | HCl and H₂SO₄ pickling line isolation and control |
| Semiconductor | Ultra-pure chemical delivery (HF, H₂O₂, NH₄OH), UPW systems |
The valve's ISO 5211 top flange supports direct mounting of:
All actuators are shop-mounted and stroke-tested before shipment. Limit switch boxes (mechanical or proximity), positioners (pneumatic, electro-pneumatic, or smart/HART), anddeclutchable manual overrides are available as factory-installed options.
Each valve undergoes the following standard tests:
A loose liner is mechanically retained inside the body and can separate under vacuum or thermal cycling, creating a gap where corrosive media can attack the metal body. A vulcanized PTFE seat is chemically bonded to the body surface, forming a single inseparable structure. It withstands full vacuum without delamination and cannot trap media behind the lining.
Standard PTFE lined valves are rated to 180°C maximum. For saturated steam above 150°C, a PFA-lined variant with reinforced stem seals is recommended. Contact our engineering team for steam-specific material selection.
Yes. Lug-style bodies are available from DN50 to DN300 in PN10/PN16 and Class 150 ratings. Lug valves permit downstream pipe removal without upstream shutdown and are suitable for end-of-line service with a blind flange.
Typical mapping: DN50–DN65 = F05, DN80–DN100 = F07, DN125–DN150 = F10, DN200–DN250 = F12, DN300 = F14. Refer to our ISO 5211 Mounting Guide for complete dimension tables and torque pairing.
The stem features a machined shoulder at the inner end that is larger than the bearing bore. Even if the external stem retainer (circlip or gland flange) is removed, the stem cannot eject under pressure. This design complies with API 609 anti-blowout requirements and provides a secondary safety barrier.
All specifications are subject to change without notice. For critical applications, request a certified dimensional drawing and material test certificate with your inquiry. PTFE and PFA are trademarks of their respective owners.
From raw material inspection to final delivery, every butterfly valve undergoes a comprehensive quality inspection to ensure reliable performance and compliance with international standards.
