Overview
D643H Pneumatic Metal Hard Sealing Butterfly Valve is a valve that adopts a metal hard sealing structure and uses compressed air as power to drive the disc in a 90° rotary motion, achieving opening/closing or regulation of pipeline media. The valve utilizes a triple-eccentric or multi-eccentric design principle, allowing the disc sealing surface to quickly disengage from and engage with the seat sealing surface during opening and closing, significantly reducing friction and wear. Its transmission mechanism outputs torque through a pneumatic actuator, driving the stem to rotate the disc precisely within the valve body. Both the seat and disc sealing pair are made of metal materials (such as cast iron, ductile iron, stainless steel, etc.), processed through special techniques to form a high-hardness metal-to-metal seal. The D643H pneumatic metal hard sealing butterfly valve is particularly suitable for severe service conditions involving high temperature, high pressure, corrosive media, and the presence of small solid particles, and is widely used in critical piping systems of industrial fields such as power, metallurgy, petrochemical, and district heating.

Product Illustration of D643H Pneumatic Hard Seal Butterfly Valve

Features

1、Metal hard sealing structure

The sealing surfaces of the seat and disc are processed using hardfacing of cast iron, ductile iron, stainless steel, or spray coating of hard materials, forming a high-hardness metal sealing pair that is wear-resistant and erosion-resistant, with a service life far exceeding that of soft-sealing butterfly valves.

2、MultiEccentric Design
Utilizing singleeccentric, doubleeccentric, or tripleeccentric construction, the disc instantly separates from the seat during valve operation, achieving frictionfree opening and closing. This results in low operating torque and minimal wear on the sealing surfaces.

3、HighTemperature and HighPressure Performance
The metal hardseal structure enables the valve to withstand higher operating temperatures (typically up to 425°C or above) and higher working pressures, making it suitable for hightemperature and highpressure media such as steam, thermal oil, and hot flue gas.

4、Pneumatic Rapid Control
Equipped with a highperformance pneumatic actuator (piston or vane type), the valve provides fast opening and closing speeds. It supports remote automatic control and integration with DCS/PLC systems to meet automated process control requirements.

5、Excellent Sealing Performance
Relying on the wedgelike compression effect generated by the eccentric design, the valve ensures tight contact of the metal sealing surfaces when closed. It offers reliable bidirectional sealing, with leakage levels reaching ANSI Class VI or higher standards.

6、Corrosion and Abrasion Resistance
The high hardness of the metal sealing surfaces, combined with the option of corrosionresistant alloy materials or surface hardening treatments for the valve body and key components, effectively resists medium corrosion and erosion from solid particles. Suitable for slurry or fluegas pipelines containing dust or particulate matter.

7、FireSafe Design
Selected models incorporate firesafe functionality. In the event of a fire, the metal sealing pair can maintain a certain degree of sealing performance even after any soft sealing materials are destroyed, preventing largescale media leakage. Complies with firesafety standards such as API 607.

8、Long Service Life and Low Maintenance
Thanks to minimal friction and high wear resistance, the valve delivers extended service life. Maintenance intervals are prolonged, allowing for longterm maintenancefree operation under normal conditions, significantly reducing overall lifecycle costs.

Structural Diagram of D641H Pneumatic Hard-sealed Butterfly Valve

Parts List and Materials Specification

Performance Specification Table

D643H Pneumatic Metal-Sealed Butterfly Valve Overall Dimension Drawing

D643H Pneumatic Metal-Sealed Butterfly Valve overall dimension table