Description
Pneumatic Hard Seal Expansion Valves (also known as metal-seated expansion gate valves) are heavy-duty isolation valves engineered for high-temperature, highly abrasive, and solid-laden fluid lines. Featuring a robust metal-to-metal seating structure, these valves handle severe thermal expansion and pipe stress while providing tight shut-off in power generation, metallurgical, and cement production systems.
Designed for automated material handling, these valves complement our industrial butterfly valves and integrate seamlessly into high-pressure piping with precision-machined industrial flanges.
Technical Specifications
| Technical Parameter | Specification Details |
|---|---|
| Nominal Diameter Range | DN50 to DN1200 (2" to 48") |
| Nominal Pressure | PN2.5 / PN6 / PN10 / PN16 / Class 150 |
| Body Material | WCB (Carbon Steel), CF8 (304 Stainless Steel), CF8M (316 Stainless Steel), Cr-Mo Alloy Steel |
| Sealing Type | Metal-to-Metal Hard Seal (Stellite / Carbide Overlay) |
| Working Temperature | -29°C to 600°C (-20°F to 1112°F) |
| Connection & Standard | Flanged / Wafer Type (ASME B16.5, DIN EN 1092-1, JB/T 8691) |
| Actuation Type | Pneumatic Cylinder (Double-acting / Single-acting with manual override) |
Key Advantages & Hard Seal Engineering
Working under harsh powder, ash, and thermal expansion conditions requires rigid mechanical design:
- Superior Abrasion & Heat Resistance: Hardened metal seating faces (hard-faced with Stellite alloy) resist severe erosion from dry ash, coal dust, and slag while remaining functional up to 600°C.
- Thermal Expansion Compensation: Specially engineered floating wedge and clearance design allows the valve gate to expand thermally without jamming or galling the seating surfaces.
- High-Torque Pneumatic Automation: Equipped with heavy-duty pneumatic cylinders for rapid shearing action, cutting through packed solids for complete flow shut-off.
Target Applications & Industries
Our pneumatic hard-sealed valves are widely specified for severe material transfer lines:
- Power Plants & Fly Ash Handling: Pneumatic ash conveying, boiler exhaust, and economizer outlets.
- Metallurgy & Steel Mills: Blast furnace gas lines, dust extraction, and sinter plant hoppers.
- Cement & Mining: Dry clinker discharge, limestone slurry, and pneumatic powder transport.
Frequently Asked Questions (FAQ)
Q1: What is the main advantage of a hard seal over a soft seal expansion valve?
Hard seals (metal-to-metal) withstand temperatures exceeding 200°C and resist mechanical wear from solid abrasives that would burn out or destroy PTFE/rubber soft seats within hours.
Q2: What accessories are included with the pneumatic actuation package?
Standard packages include solenoid valves, limit switch boxes for open/close feedback, air filter regulators, and optional manual handwheel overrides for emergency operation.
Q3: Can Oucang Valve manufacture custom face-to-face dimensions?
Yes. As a direct factory, Oucang Valve manufactures custom face-to-face lengths, special flange bolt patterns, and high-alloy hard facing based on your piping drawings.
About the Manufacturer: Oucang Valve
Oucang Valve is an ISO-certified manufacturer specializing in high-temperature, severe-service industrial valves and forged pipe flanges. Operating our own machining and testing facility, we provide complete pressure testing, material certificates, and OEM design solutions for global energy and industrial clients.
- Core Capability: Hard-facing alloy overlay welding, custom large-diameter valves (up to DN1200), and rapid factory direct export.
- Quality Compliance: ASME, DIN, JIS, and GB piping standards.
- Factory Inquiry: Contact our engineering sales team for direct factory quotations and technical drawings.
