Product Overview

The Laux Valve double offset  butterfly valve with CF8M disc is a high-performance valve designed for demanding applications where standard concentric rubber-seated valves cannot perform reliably. The CF8M cast stainless steel disc (equivalent to 316 SS) provides superior corrosion resistance in chemical, steam, and high-temperature industrial environments.

The double offset cam action lifts the disc completely free of the seat within the first 10 degrees of opening, eliminating seat rubbing and dramatically extending service life. The PTFE or reinforced polymer seat delivers bi-directional bubble-tight shut-off at full rated pressure, making this valve ideal for chemical processing, steam systems, thermal oil, high-temperature water, and refinery service.

Key Features

• CF8M  Disc — ASTM A351 CF8M stainless steel disc provides outstanding corrosion resistance across a wide range of chemical media, including acids, alkalis, and chlorides. Superior to 304 SS and far more durable than coated iron discs in aggressive environments.
• Double Offset  — Two precision offsets lift the disc completely free of the seat during the first 10 degrees of rotation. Zero seat rubbing means virtually no seat wear during cycling, delivering 3-5x longer seat life than concentric valves in high-cycle applications.
• PTFE / Reinforced Polymer Seat — Replaceable PTFE seat ring with 316 SS retainer. PTFE provides near-universal chemical resistance, low friction, and temperature range of -20°C to +200°C (up to 260°C with PEEK option).
• Bi-Directional Bubble-Tight Shut-Off — Zero leakage in both flow directions at full rated pressure, meeting API 598 Class VI seat leakage requirements.
• Integral Flange Body Design — Flanged connections (ASME B16.5 Class 150-600 or EN 1092-2) provide rigid installation and dead-end capability.
• Replaceable Seat — PTFE or polymer seat ring is field-replaceable. No need to replace the entire valve when service conditions change or after extended use.
• Fire-Safe Design Available — Optional API 607 fire-safe design with secondary metal seat for hydrocarbon and refinery service.
• Blowout-Proof Stem — One-piece 316 SS stem with internal thrust bearing and external gland seals. Replaceable stem seals under pressure.
• ISO 5211 Mounting Pad — Standardized mounting pad for gear operator, pneumatic actuator, or electric actuator.
• 100% Factory Tested — Shell test at 1.5x rated pressure, seat test at 1.1x rated pressure per API 598.

Double Offset Design — How It Works

Offset 1 — Stem Behind Seat Centerline

The shaft axis is positioned behind the seat sealing plane (toward the downstream side). As the disc begins to open, the disc moves axially away from the seat, breaking the seal with minimal friction.

Offset 2 — Stem Offset from Pipe Centerline

The shaft axis is offset from the pipe centerline (toward one side of the bore). As the disc rotates, the disc moves radially away from the seat. The combination of axial and radial movement creates a true cam effect that lifts the disc completely free of the seat.

Result: No Seat Wear

Unlike concentric butterfly valves where the disc rubs against the seat during every cycle, the double offset design ensures the disc contacts the seat only in the fully closed position. This eliminates seat wear as a failure mode and allows the valve to use harder, more durable seat materials such as PTFE, reinforced PTFE, and PEEK.

Technical Specifications

• Chemical Processing — Acids, caustics, solvents, and chemical intermediates where CF8M disc and PTFE seat provide chemical resistance that elastomers cannot match.
• Steam Service — Saturated steam up to 200°C for process heating, sterilization, and tracing systems.
• Thermal Oil / Heat Transfer Systems — High-temperature thermal oil in chemical plants, plastic/rubber processing, and food processing.
• HVAC High-Temperature Hot Water — District heating, boiler isolation, and high-temperature hot water systems (120-180°C).
• Oil & Gas / Refinery — Fire-safe version (API 607) for hydrocarbon service, fuel oil, and light hydrocarbons.
• Power Generation — Turbine cooling water, condensate systems, auxiliary steam, and process water.
• Pulp & Paper — Black liquor, green liquor, and high-temperature process streams.
• Pharmaceutical & Biotech — Clean steam, WFI (water for injection), and CIP/SIP systems where CF8M disc provides clean, corrosion-resistant surfaces.

Why Choose Laux Valve for Double Offset Butterfly Valves?

• 15+ Years of Manufacturing Experience — Export to 45+ countries with consistent quality and reliability
• Full Material Traceability — All CF8M discs supplied with material test certificates (MTC)
• ISO 9001:2015 Certified — Complete quality management from casting to final testing
• Competitive Pricing — Factory direct pricing without middlemen
• Short Lead Times — 15-25 working days for standard configurations
• Technical Support — Application engineering team for material selection and custom designs

Frequently Asked Questions

Q: What is the difference between CF8M and 316 SS?

A: CF8M is the cast equivalent of wrought 316 stainless steel. Both have similar chemical composition (16-18% Cr, 10-14% Ni, 2-3% Mo) and corrosion resistance. CF8M is used for cast components (disc, body), while 316 is typically used for wrought products (stem, plate). For butterfly valve discs, CF8M casting delivers the same corrosion resistance as 316 SS at a more cost-effective price point.

Q: Can this valve handle saturated steam?

A: Yes. With PTFE seat, the double offset butterfly valve handles saturated steam up to 200°C. For higher temperature steam up to 260°C, upgrade to the PEEK seat option. The CF8M disc has no temperature limitation in steam service.

Q: How does the double offset design extend seat life?

A: In a standard concentric valve, the disc rubs against the seat during every open/close cycle, gradually wearing the seat material. The double offset cam action lifts the disc completely free of the seat within the first 10 degrees of rotation. The seat is only contacted at the fully closed position. This eliminates friction-based wear and extends seat life by 3-5x in cycling applications.

Q: What is the difference between double offset and triple offset?

A: Double offset (API 609 Category B) uses a PTFE or polymer seat with two offsets. Triple offset (API 609 Category C) adds a third offset that creates a metal-to-metal seat with a seating angle, suitable for higher temperatures (500°C+) and fire-safe applications. For most chemical, steam, and high-temperature water applications up to 260°C, double offset provides the best value.

Q: Is the PTFE seat replaceable in the field?

A: Yes. The PTFE seat ring and 316 SS retainer can be replaced in the field without removing the valve from the pipeline. Replacement seat kits are available from stock.

Q: What is the lead time for a CF8M disc double offset valve?

A: Standard configuration lead time is 15-25 working days. Full stainless steel body (CF8M body + CF8M disc) may require 20-30 working days. Contact our sales team for current lead times.

Ordering Information

For pricing, technical drawings, or material certifications, contact our sales team:

Email: james@lauxvalve.com | Tel / WhatsApp: +86 18920833829

Please provide the following for a quotation: size, pressure rating (Class 150/300/600), body material, seat material, operation type, and quantity.

Butterfly Valve Manufacturing Process
From Technical Confirmation to Final Delivery



Standardized Quality Control Process

From raw material inspection to final delivery, every butterfly valve undergoes a comprehensive quality inspection to ensure reliable performance and compliance with international standards.

International Certifications

Manufactured to international quality standards and certified for global industrial and potable water applications.