National Standard Clamp Butterfly Valve

Description

Standard butterfly valves often experience seat friction and wear during operation. This clamp-style valve overcomes these issues through three distinct offsets:

1. First Offset: The shaft is located behind the sealing face, allowing for a continuous seal.
2. Second Offset: The shaft is displaced from the pipe centerline, which allows the plate to swing clear of the seat.
3. Third Offset (The Eccentric Angle B): A unique conical sealing geometry is introduced.

This configuration ensures that the butterfly plate and the valve seat only make contact at the final point of closure. This frictionless operation significantly reduces torque requirements and prevents the common “scuffing” that shortens the lifespan of ordinary valves.

Features

• Multi-Level Metal Seal: The sealing ring on the butterfly plate consists of interleaved layers of stainless steel and flexible graphite/PTFE. This provides a “dual advantage”—the high-temperature durability of metal and the leak-proof flexibility of a soft seal.
• Torque-Tightened Sealing: The “more closed, more tight” design means that the sealing force is generated by the applied torque rather than just position. This allows for adjustable sealing pressure to ensure a “never-pass” performance.
• Stellite Hardened Surface: The valve seat sealing surface is built up with cobalt-based alloy (Stellite) welding. This provides extreme resistance to wear, erosion, and high-velocity fluid impact.
• Compact Clamp Design: The thin, clamp-style body fits easily between piping flanges, saving significant space and reducing the overall weight of the piping system.

Specifications

Applications

• Metallurgy: Hot air blast systems and flue gas control in steel mills.
• Petrochemical Refining: High-temperature vapor processing and catalyst handling.
• Power Plants: Circulating water systems and steam extraction isolation.
• Industrial Drainage: Regulation and shut-off in large-caliber pressurized drainage pipes.