Large-Diameter Butterfly Valve Packing, Graphite, 170*186 mm

Product Name: Low-Emission Packing Set for Large-Diameter Butterfly Valves
Model: M641
Size: ID 170 mm * OD 186 mm (single-side width 8 mm)
Material Properties:
Graphite Purity: ≥99.5 %
Construction: Anti-oxidation graphite + braided Inconel 600 wire (20 %)
Sulfur Content: ≤50 PPM
Chlorine Content: ≤20 PPM
Certifications: ISO 15848-1, TA-Luft, API 622
Operating Conditions: –45 °C to +425 °C

Operating Parameters

Speed: 2 m/s
Temperature Range: -200°C to +400°C (for most media), -200°C to +550°C (for steam)
pH Value: 0 to 14
Pressure: 25 MPa
Media: Suitable for most chemical substances (solvents, hydrocarbons, acids, alkalis, steam, alcohol, oil)
Except for strong oxidizing acids, such as sulfuric acid and nitric acid.

Key Benefits

The packing compensates for large stem diameters and narrow packing widths.
High rebound and deformation ensure tight seal despite micro-movements.
Full compliance with international low-emission standards.

Design Challenge & Solution

Narrow Width + Large Stem: With only 8 mm side width, the packing must compensate for stem micro-movement (less than 0.8 mm at 10 % graphite rebound) while allowing for machining tolerances (about 0.15–0.2 mm).
Special Geometry: A butterfly (convex-concave) and upper/lower V-ring configuration is adopted to:
1. Increase graphite expansion capability.
2. Provide greater radial deformation for large-size packings.
High-Density End Rings (2.5-2.6 g/cm³): Transmit bolt preload rapidly to the centre pure-graphite rings, causing immediate deformation and sealing.
Sequential Deformation: Centre rings reach min 1.6 g/cm³ to end rings deform to stable, self-reinforcing seal (validated by extensive testing and field use).