Welded Rotary Valve

1. Basic structure of welded rotary valve
(1) Valve Body
● Material: Carbon Steel (WCB), Stainless Steel (CF8/CF8M), Alloy Steel (WC6/WC9)

● Connection method: butt welding, according to the standard ANSI B16.25 groove.

● Design: Usually short design to reduce the heat-affected area of welding.

(2) Swivel Plate
Construction Type:

● Concentric type (central symmetry, use of low pressure).

● Double eccentric (reduce friction, increase service life).

● Triple eccentric (high pressure and high temperature, zero leakage).

● Material: Stainless steel (SS316), alloy steel (surface quenching treatment).

(3) Sealing system
● Soft sealing: EPDM, NBR, PTFE (≤200°C).

● Metal solid seal: stainless steel graphite (≤600°C), in accordance with API 607 fire protection standard.

(4) Valve stem
● One-piece forging to avoid welding weak points and the risk of breakage.

● Material: SS316, 17-4PH (High Strength Corrosion Resistant Alloy)

2. Characteristics of Welded Butterfly Valves
✅ Benefits
● Zero leakage: The welded joint completely eliminates the risk of flange leakage.

● High pressure and high temperature resistance: The three-eccentric design can reach the class of 600 (PN100), 600°C.

● Compact Structure: No flange, suitable for piping layout with limited space.

● Maintenance-free: Welding eliminates bolt loosening problems and ensures high long-term stability.

● Anti-vibration protection: The welded structure is suitable for high vibration environments (such as ships and compressor pipelines).

3. Main Applications
● Oil and natural gas: high-pressure oil and gas pipelines, import and export of LNG storage tanks.

● Chemical industry: pipelines for highly corrosive media (such as sulfuric acid and liquid ammonia).

● Power Industry: Boiler Steam Systems, High Temperature Gas Pipelines

● Pharmaceutical/Food & Beverage: Sterile piping (using sanitary-welded butterfly valves)

● Nuclear industry: transportation of radioactive media (special certification of materials is required).