The Split Body Full PTFE Lining Double Flange Butterfly Valve is a corrosion-resistant isolation valve designed for aggressive acids, alkalis, solvents, and high-purity process fluids. The split-body design facilitates inspection and maintenance, while the full PTFE/PFA lining isolates all wetted metal surfaces from the process medium. Double-flange construction provides full bidirectional pressure capability and standard flanged piping installation.
The split body design allows the valve to be opened for inspection, cleaning, or liner replacement without removing the entire valve from the pipeline. The body halves are bolted together with corrosion-resistant fasteners, and the mating surfaces are sealed to prevent leakage to atmosphere. This construction is especially suitable for chemical plants, pharmaceutical facilities, and applications where internal inspection is required.
The full PTFE or PFA lining covers all wetted surfaces of the body and disc, eliminating metal exposure to the process fluid. PTFE provides near-universal chemical resistance, low friction, and non-stick properties. For thermal cycling above 150°C, PFA can be selected for improved resistance to stress cracking and cold flow.
| Item | Technical Benefit |
|---|---|
| Split body construction | Allows internal inspection and maintenance without cutting the valve out of the pipeline. |
| Full PTFE / PFA lining | Isolates all wetted metal surfaces from aggressive process media; no coating pinholes or exposed metal in the flow path. |
| PTFE/PFA encapsulated disc | Protects the disc face, edge, and hub from corrosion, pitting, and media adhesion. |
| Double flange body | Full bidirectional pressure rating and standard flanged installation, suitable for end-of-line service. |
| Blowout-proof stem | Machined shaft shoulder prevents stem ejection under pressure, meeting API 609 anti-blowout requirements. |
| Self-adjusting stem seal | PTFE V-ring pack with live-loading compensates for wear and thermal expansion. |
| ISO 5211 top flange | Direct mounting of manual gear, pneumatic, or electric actuators. |
| Parameter | Specification |
|---|---|
| Nominal Diameter | DN50, DN65, DN80, DN100, DN125, DN150, DN200, DN250, DN300, DN350, DN400, DN450, DN500, DN600 |
| Pressure Rating | PN10 / PN16 / ANSI Class 150 |
| Body Style | Split Body, Double Flange |
| Face-to-Face | EN 558 Series 20 / API 609 Category A depending on configuration |
| Flange Drilling | EN 1092-2 / ANSI B16.5 Class 150 / ASME B16.42 Class 150 |
| Top Flange | ISO 5211 F05-F14 depending on valve size |
| Seat Test | 1.1 times rated pressure, bidirectional, zero visible leakage |
| Shell Test | 1.5 times rated pressure, water, per EN 12266-1 / API 598 |
| Operating Temperature | -29°C to +180°C depending on lining material |
| Parts | Material | Standard |
|---|---|---|
| Body | Ductile Iron / WCB / CF8M | ASTM A536 / A216 / A351 |
| Body Lining | Full PTFE / PFA | ASTM D4894 / D3307 |
| Disc | Ductile Iron / CF8M with full PTFE/PFA Linning | ASTM A536 / A351 |
| Seat | PTFE / PFA | ASTM D4894 |
| Shaft | SS431 / 17-4PH | ASTM A276 |
| Internal Fasteners | SS316 / Hastelloy optional | ASTM A276 / B574 |
PTFE is inert to most industrial chemicals and process fluids, including concentrated acids, caustic solutions, chlorinated solvents, and oxidizing media. The full lining prevents the process medium from contacting the metal body, which eliminates under-liner corrosion and extends valve service life.
| Lining Material | Typical Temperature Range | Recommended Service |
|---|---|---|
| PTFE | -29°C to +150°C | Strong acids, alkalis, solvents, high-purity water, general chemical service |
| PFA | -29°C to +180°C | Thermal cycling, higher-temperature chemical service, improved stress-crack resistance |
| PTFE encapsulated disc | -29°C to +150°C | Corrosive media with full disc protection |
| PFA encapsulated disc | -29°C to +180°C | Aggressive media with improved resistance to cold flow and cracking |
| Industry | Application |
|---|---|
| Chemical Processing | Acid transfer, solvent handling, reactor feed and discharge, corrosive utility lines |
| Pharmaceutical | High-purity water, CIP/SIP support lines, sterile process utilities |
| Food & Beverage | CIP return lines, edible oil processing, sugar refining |
| Water Treatment | Chlorine dosing, hypochlorite lines, acid and alkali dosing skids |
| Pulp & Paper | Chlorine dioxide, bleaching chemicals, and corrosive process media |
| Steel Pickling | HCl and H2SO4 pickling line isolation and control |
The valve body includes an ISO 5211 top flange for direct actuator mounting. Available operator configurations include:
Factory-mounted operator assemblies are stroke-tested before shipment. Limit switches, positioners, and declutchable manual overrides are available as options.
Each valve receives the following standard inspection and test operations:
Material test certificates per EN 10204 3.1, PMI, lining thickness verification, and third-party witnessed testing are available on request.
It is a double-flanged butterfly valve with a split body design and full PTFE or PFA lining on all wetted surfaces. The split body allows internal inspection and maintenance, while the full lining isolates the process medium from the metal body and disc.
PTFE offers excellent chemical resistance and low friction. PFA provides similar chemical resistance with improved resistance to stress cracking and cold flow, making it better suited for thermal cycling and higher-temperature service.
Vacuum capability depends on the lining and seat configuration. For full vacuum or vacuum cycling, confirm the specific size, lining material, and body configuration with Laux Valve engineering.
The product described here is double flange. Wafer and lug configurations are available in other Laux Valve PTFE lined butterfly valve series. Double flange construction is suitable for full-pressure end-of-line service.
From raw material inspection to final delivery, every butterfly valve undergoes a comprehensive quality inspection to ensure reliable performance and compliance with international standards.
