| Category | Standard |
|---|---|
| Design & Manufacture | API 609 Category A, , EN 593, GB/T 12238 |
| Face-to-Face Dimensions | ISO 5752, API 609, EN 558 Series 13, GB/T 12221 |
| Flange Connection | ANSI B16.1 / B16.5, EN 1092-2, BS 4504 |
| Testing & Inspection | ISO 5208, API 598, EN 12266-1 |
| Actuator Interface | ISO 5211 (top mounting pad) |
| Materials | ASTM B148 (C95800),C95400 |
Many manufacturers offer Al-Bronze trim (disc only) while using a coated iron body. In seawater service, this is a compromise — coatings fail. Laux Valve's full Al-Bronze body and disc eliminates this risk entirely.
| Property | Al-Bronze C95800 | 316 SS (CF8M) | Duplex 2205 | Ductile Iron + Coating |
|---|---|---|---|---|
| Seawater Corrosion Rate | ≤ 0.02 mm/year | 0.5–2.0 mm/year (pitting) | ≈ 0.02 mm/year | Coating-dependent (risk of underfilm) |
| Crevice Corrosion | Immune | Highly susceptible | Resistant (limit ≈ 25°C) | Severe at coating defects |
| Galvanic with CuNi Pipe | Compatible | Not compatible | Partially compatible | Not compatible |
| Biofouling Resistance | Natural copper ion release | Poor (fouls rapidly) | Poor | Coating-dependent |
| Cost Index (relative) | 4× Ductile Iron | 2–2.5× Ductile Iron | 3.5–4× Ductile Iron | 1× (baseline) |
| Service Life in Seawater | 30+ years | 5–10 years | 15–20 years | 10–15 years (if coating intact) |
| Part | Standard | Optional Upgrade | Rationale for Seawater |
|---|---|---|---|
| Body | Al-Bronze C95800 ASTM B148 |
C63200 (Nickel-Al-Bronze) | Full corrosion resistance on all wetted surfaces |
| Disc | Al-Bronze C95800 ASTM B148 |
C63200 / Duplex 2205 | Primary flow surface; must match or exceed body performance |
| Stem | Super Duplex 2507 (UNS S32750) |
Inconel 625 / Monel K500 | PREN ≥ 40 required for seawater pressure boundary |
| Seat | EPDM | Viton (FKM) / Neoprene | EDPM: standard seawater. Viton: chemical/thermal. Neoprene: budget marine |
| Shaft Bearings | AL-Bronze | Al-Bronze self-lubricating | Low friction, no grease, seawater-compatible |
| External O-Rings | Viton (FKM) ASTM D2000 |
EPDM (UV applications) | UV & ozone degradation resistance for topside exposure |
| Fasteners | Duplex 2205 ASTM A276 |
Super Duplex 2507 / Monel K500 | All bolting must be seawater-resistant |
| End Cover / Gland | Al-Bronze C95800 | – | Zero coating = zero maintenance |
316 stainless steel in a crevice (stem-to-bearing clearance) with stagnant seawater is a known failure mode. Super Duplex 2507 has a Pitting Resistance Equivalent Number (PREN) of ≥ 40, making it reliably immune to crevice corrosion in seawater up to 30°C, which covers the vast majority of butterfly valve applications. For higher temperatures or extreme chlorination, we specify Inconel 625 (PREN ≥ 50).
Laux Valve Al-Bronze butterfly valves feature a mechanically retained vulcanized seat with a stainless steel retaining ring. This design is preferred in seawater service for three critical reasons:
Seat Material Selection for Seawater| Material | Temp. Range | Seawater | Chlorinated | Brine | Hydrocarbons | Cost |
|---|---|---|---|---|---|---|
| EPDM | -30~120°C | ★★★★★ | ★★★★☆ | ★★★★★ | ★☆☆☆☆ | Standard |
| Viton (FKM) | -20~180°C | ★★★★☆ | ★★★★★ | ★★★★★ | ★★★★★ | Premium |
| Neoprene (CR) | -20~100°C | ★★★★☆ | ★★★☆☆ | ★★★★☆ | ★★★☆☆ | Standard |
| NBR (Buna-N) | -20~80°C | ★★★☆☆ | ★★☆☆☆ | ★★☆☆☆ | ★★★★☆ | Budget |
| Silicone (VMQ) | -40~200°C | ★★★☆☆ | ★☆☆☆☆ | ★★☆☆☆ | ★☆☆☆☆ | Premium |
| Test | Standard | Requirement | Our Result |
|---|---|---|---|
| Shell Hydrostatic | ISO 5208 / API 598 | 1.5 × rated, zero visible leakage | Pass: 100% tested |
| Seat Leakage (High Pressure) | ISO 5208 Rate A | 1.1 × rated, ≤ Rate A | Pass: Rate A (bubble-tight) |
| Seat Leakage (Low Pressure) | ISO 5208 Rate A | 0.6 bar, ≤ Rate A | Pass: zero visible leakage |
| Endurance Cycling | API 609 | ≥ 250 cycles without leak increase | Pass: ≥ 500 cycles |
All Laux Valve Al-Bronze butterfly valves feature an ISO 5211-compliant top mounting pad as standard, enabling direct mounting of any compliant actuator or gearbox.
| Mode | Range | Features | Typical Application |
|---|---|---|---|
| Manual Lever | DN50–DN200 | 10-position locking plate, adjustable | Simple on/off, infrequent operation |
| Worm Gearbox | DN150–DN1200 | Handwheel, self-locking, position indicator | Large diameter manual operation, buried service |
| Electric Actuator | DN50–DN1200 | 4–20mA / Modbus / Profibus, IP67/IP68 | Remote operation, SCADA integration, control valves |
| Pneumatic Actuator | DN50–DN600 | Double-acting or spring-return, ATEX certified | Firewater deluge, emergency shutdown (ESD) |
| Hydraulic Actuator | DN300–DN1200 | High torque, subsea capable | Offshore, submerged service, safety systems |
Al-Bronze butterfly valves are specified throughout SWRO plants from intake to brine outfall. Typical locations include:
On offshore platforms and FPSOs, weight, space, and maintenance access are at a premium. Al-Bronze double flange butterfly valves replace heavy, maintenance-intensive gate valves in:
Once-through and recirculating seawater cooling systems require high-capacity, reliable isolation. Our DN600–DN1200 Al-Bronze butterfly valves serve:
LNG receiving and export terminals on coastal sites use large-diameter butterfly valves in seawater vaporization systems:
Al-Bronze's natural biofouling resistance makes it the valve material of choice aboard vessels:
In seawater service, Al-Bronze typically provides 3–5× the service life of 316 SS, while the initial cost premium is approximately 1.5–2×. The breakeven point is reached within the first 5 years of operation due to eliminated coating maintenance, no replacement of corroded components, and reduced downtime. For critical and inaccessible installations (buried, submerged, offshore), Al-Bronze is the only reliable choice.
Yes. Al-Bronze C95800 has demonstrated excellent resistance to sodium hypochlorite at concentrations typical of desalination feed chlorination (≤ 5 ppm continuous). For chlorine dioxide or higher concentrations, please contact our engineering team for specific recommendations.
The vulcanized seat is designed for minimal maintenance. Visual inspection every 2–3 years is recommended. If seat damage is observed (scoring, permanent deformation, cracking), the seat can be replaced in 1–2 hours without removing the valve body from the pipeline. Laux Valve stocks spare seat cartridges for all standard sizes.
Yes — and Al-Bronze is actually preferred for buried service because there is zero risk of coating damage or cathodic disbondment. Unlike coated iron valves, an Al-Bronze valve cannot suffer underfilm corrosion. Standard buried service requires a handwheel extension and gearbox with indicator post.
The double flange concentric butterfly valve is bi-directional — it seals equally in both flow directions at full rated pressure. This simplifies installation and allows the valve to be placed in either orientation.
Yes. We manufacture to any flange drilling standard: EN 1092-2 PN6/10/16/25, ANSI B16.1 Class 125/250, ASME B16.5 Class 150, AS 4087 (Australia), JIS B2220 (Japan), and BS 4504 (UK). Custom drilling patterns are available upon request.
Standard documentation package: Inspection & Test Plan (ITP), hydrostatic test report, material certificates (EN 10204 3.1), operating manual, and installation instructions. Extended documentation (MDR, 3.2 certificates, NDE reports, coating reports) available for project requirements.
To provide an accurate quotation, please provide:
Contact Laux Valve today — our seawater applications team is ready to support your next project.
From raw material inspection to final delivery, every butterfly valve undergoes a comprehensive quality inspection to ensure reliable performance and compliance with international standards.
