PTFE Fully Lined Butterfly Valve – Lugged Type
Description
Technical Data Sheet
Product: PTFE Fully Lined Butterfly Valve – Lugged Type
Body: Ductile Iron (DI) with PTFE Lining / Disc: CF8M with PTFE Encapsulation
Type: PTFE Lined, Full Bore, Bubble-Tight Shutoff
1. General Description
This valve is a fully lined butterfly valve designed for extremely corrosive chemical services where high purity and universal corrosion resistance are required. The entire wetted surface of the body is completely lined with a seamless PTFE (PFA optional) liner, and the disc is manufactured from CF8M (316 Stainless Steel) fully encapsulated in moulded PTFE. The seal is achieved by the interference fit between the PTFE-lined disc and the PTFE body liner, providing a bi-directional bubble-tight shutoff without the need for a separate seat ring. The lugged body design allows dead-end service and downstream pipe removal while the upstream line remains pressurized.
2. Design, Manufacturing & Inspection Standards
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Design Standard: API 609 Category A (Lug Type), MSS SP-67 / EN 593
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Pressure Rating: Class 150 / PN10 / PN16 (Standard: Class 150 or PN16)
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Face-to-Face: API 609 Table 2 (Long Pattern) or ISO 5752 Series 20
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Flange Drilling: ASME B16.5 Class 150 / EN 1092-2 PN16
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Lug Drilling: Tapped lugs as per standard flange bolt holes
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Testing & Inspection: API 598 (Zero Leakage Closure Test)
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Lining Integrity: Spark Test 10 kV DC (no pinholes)
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Marking: MSS SP-25
3. Technical Parameters
| Parameter | Specification |
|---|---|
| Nominal Size | DN50 – DN600 (2″ – 24″) |
| Pressure Class | Class 150 (PN20) or PN10/PN16 (specify) |
| Body Material | Ductile Iron ASTM A536 Gr. 65-45-12 (GJS-500-7) |
| Body Lining | Virgin PTFE (Polytetrafluoroethylene), ≥ 3 mm thickness, seamless moulded |
| Disc Material (Core) | CF8M (ASTM A351), 316 Stainless Steel |
| Disc Encapsulation | Virgin PTFE, fully moulded and fused to disc core, ~3-5 mm thick |
| Seat/Seal Principle | Body PTFE liner acts as seat, sealing against PTFE encapsulated disc |
| Shaft Material | SS316 (CF8M) or Hastelloy C (on request) |
| Shaft Sealing | PTFE chevron V-rings or PTFE-encapsulated Viton O-rings, externally adjustable |
| Bearings | PTFE / Graphite composite or pure PTFE bushings |
| Operating Mechanism | Manual Lever (up to DN150) / Gearbox (≥DN200 or larger) / Actuator mounting pad ISO 5211 |
| Lug Design | Full lugged, suitable for dead-end service at full rated pressure |
| Media Temperature Range | -29°C to +150°C (-20°F to +300°F) continuous Max +180°C (+356°F) intermittent (check pressure derating) |
| Suitable Media | Strong acids (HCl, H₂SO₄, HNO₃ up to certain concentrations), alkalis, organic solvents, ultra-pure water, chlorine, brine – refer to PTFE chemical compatibility |
| Leakage Rate | Bubble-tight, zero visible leakage (API 598) |
| Coating | External: Standard epoxy paint (anti-corrosive) |
4. Materials of Main Parts
| No. | Part Name | Material |
|---|---|---|
| 1 | Body | Ductile Iron ASTM A536 65-45-12, internally lined with PTFE |
| 2 | Disc Core | CF8M (SS316), fully encapsulated in PTFE |
| 3 | Stem (Upper/Lower) | ASTM A276 SS316 |
| 4 | Body Liner | Virgin PTFE (white), one-piece moulded, minimum thickness 3 mm |
| 5 | Disc PTFE Encapsulation | Virgin PTFE, isostatically moulded, securely bonded |
| 6 | Stem Seals | PTFE V-ring packing or PTFE coated Viton O-rings |
| 7 | Thrust Bearing | PTFE / 25% Glass-filled PTFE |
| 8 | Stem Bearings | PTFE / Carbon-graphite bushings |
| 9 | Gland Packing Follower | SS316 or PTFE |
| 10 | Lug Inserts (Threaded) | Carbon Steel, Zinc Plated (SS316 optional) |
| 11 | Handle / Gearbox Housing | Ductile Iron / Carbon Steel, weatherproof |
5. Main Dimensions and Weights (Class 150 Lugged, Long Pattern, ISO 5752 Series 20)
Dimensions for gear operated valves. Handwheel diameter for gear operator is not included.
| DN | Size (in) | L (mm) | ØD (Flange OD) | H1 (Center to top of stem) (mm) | H2 (Center to handwheel) (mm) | Approx. Weight (kg) |
|---|---|---|---|---|---|---|
| 50 | 2 | 43 | 152 | 100 | 210 (lever) | 6 |
| 80 | 3 | 46 | 190 | 130 | 260 (lever) | 9 |
| 100 | 4 | 52 | 228 | 145 | 300 (lever/gear) | 12 |
| 150 | 6 | 56 | 280 | 190 | 350 (gear) | 20 |
| 200 | 8 | 60 | 343 | 230 | 420 (gear) | 35 |
| 250 | 10 | 68 | 406 | 275 | 480 (gear) | 55 |
| 300 | 12 | 78 | 483 | 325 | 550 (gear) | 85 |
| 400 | 16 | 102 | 600 | 420 | 680 (gear) | 155 |
| 500 | 20 | 127 | 715 | 510 | 820 (gear) | 260 |
| 600 | 24 | 154 | 840 | 600 | 950 (gear) | 390 |
Note: Above dimensions are typical values for gear operated valves with ISO F10/F12/F14 top flange. Actual dimensions may vary slightly per manufacturer. Final certified drawing prevails.
6. Pressure-Temperature Ratings (Body: Ductile Iron, Liner/Disc: PTFE)
The pressure rating is limited by both the DI body (Class 150) and the PTFE lining integrity. The table shows the maximum allowable working pressure (non-shock) in bar for virgin PTFE lining at various temperatures.
| Temperature (°C) | Max. Working Pressure (bar) – Class 150 Body |
|---|---|
| -29 to 50 | 19.6 |
| 100 | 16.5 |
| 120 | 14.5 |
| 150 | 12.0 |
| 180 | 9.0 |
Test Pressures (Ambient)
Shell Test (1.5 x 19.6): 29.4 bar
Seat Test (1.1 x 19.6): 21.6 bar – Zero leakage
7. Installation and Maintenance Notes
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Orientation: Can be installed horizontally or vertically. For best performance, keep the stem horizontal or vertical; avoid stem at the bottom to prevent debris in bearings.
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Dead-End Service: Fully lugged design allows downstream removal at full rated pressure. Ensure lugs are bolted securely.
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Flange Gaskets: No additional gaskets are required – the PTFE body liner face acts as an integral flange seal. However, flat sheet PTFE or spiral wound gaskets can be used on older flanges.
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Operation: Do not over-torque the valve at the fully open or closed position (usually ±5° over travel). For lever-operated valves, use a lockable lever in modulating services to prevent vibration.
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Chemical Compatibility: Verify PTFE compatibility with the specific chemical, especially at elevated temperatures. Avoid handling molten alkali metals, fluorine gas at high pressure, and certain fluorine compounds.
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Spark Test: After installation or maintenance, a spark test is recommended to check lining integrity.
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Maintenance: The stem packing is externally adjustable. If leakage occurs, tighten the gland follower evenly. If leakage persists, replace the stem packing with the valve in the closed position and line depressurized.
8. Ordering Information
Please provide the following:
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Nominal size and pressure class (e.g., DN100 Class 150)
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Body material (Ductile Iron with PTFE liner)
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Disc material (CF8M + PTFE encapsulated)
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Connection: Lugged (specify flange standard: ASME B16.5 or EN 1092)
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Operation: Lever, Gearbox, or Bare stem with ISO mounting for actuator
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Media type, concentration, and operating temperature
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Special requirements: Hastelloy shaft, conductive PTFE (anti-static), fire-safe design (not typical for PTFE lined), lockable lever, etc.
If you need a PN10 or PN16 dimension table, specific details for gearbox or actuated versions, or a quick chemical compatibility chart for common media with PTFE, please let me know.
