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The LINKV flat gate valve with Class 150 WCB carbon steel body and rising stem is engineered for natural gas transmission and distribution pipeline systems. Manufactured in a 49,000 m² production facility with over 200 technical personnel, each valve conforms to API 6D and ASME B16.34 standards. The parallel flat gate design provides full bore flow with minimal pressure drop, suitable for long-distance gas pipelines and city gate stations. Certifications include ISO 9001:2015, API 6D, CE/PED, and TS special equipment license. The rising stem design allows visual indication of valve position and protects stem threads from process media.
The flat gate valve uses a parallel double-disc gate structure with floating seat design. The two gate discs are pressed against the seats by spring force, achieving bi-directional sealing. The flat gate surface is hardfaced with Stellite alloy to a thickness of 1.5 mm with hardness HRC 38-45, providing wear resistance for frequent operation. Full bore design matches pipeline internal diameter, reducing flow resistance and enabling pipeline pigging operations.
The outside screw and yoke (OS&Y) rising stem design provides clear visual indication of valve open or closed position. The stem threads are located above the packing, isolated from process media to prevent corrosion and contamination. Stem material is A105 carbon steel with nitriding surface treatment for improved wear resistance. The yoke is cast integrally with the bonnet for structural rigidity during high-cycle operation.
The valve body is cast from WCB carbon steel conforming to ASTM A216 standards, suitable for natural gas service up to Class 150 pressure rating. The bolted bonnet connection uses spiral wound gaskets with 304 stainless steel inner and outer rings. The body cavity is designed to drain accumulated condensate through a drain plug at the bottom. Grease injection fittings are provided for seat and stem lubrication without valve disassembly.
Parameter | Specification |
|---|---|
Size Range | DN50 – DN400 (2" – 16") |
Pressure Rating | Class 150 (PN20) |
Body Material | WCB carbon steel (ASTM A216) |
Gate Material | A105 carbon steel with Stellite hardfacing |
Seat Material | 304 stainless steel with Stellite overlay |
Stem Material | A105 carbon steel, nitrided surface |
End Connections | Flanged RF (ASME B16.5 Class 150); Butt weld (ASME B16.25) |
Operation | Handwheel (standard); Gear operator (DN250 and above); Pneumatic (optional) |
Temperature Range | -29°C to +200°C (standard) |
Bore Design | Full bore (standard); Reduced bore (optional) |
Leakage Rate | Zero visible leakage per API 598; Gas seat test per API 6D |
Design Standard | API 6D, ASME B16.34 |
Face-to-Face | API 6D, ASME B16.10 |
Testing Standard | API 598, API 6D |
This flat gate valve series is designed for natural gas transmission and distribution pipelines. It is installed at compressor stations, city gate stations, district regulating stations, and pipeline branch connections. The full bore design allows pipeline inspection gauges (pigs) to pass through for cleaning and inspection operations. The bi-directional sealing capability enables installation in either flow direction without performance degradation.
Beyond natural gas pipelines, the valve is suitable for other non-corrosive gas and liquid services in industrial operations. Applications include compressed air systems, nitrogen distribution lines, propane and butane storage facilities, and oilfield gathering systems. The Class 150 pressure rating covers most low to medium pressure transmission and distribution networks. Carbon steel construction provides mechanical strength for buried and above-ground pipeline installations.
Each WCB valve body undergoes ultrasonic testing for casting integrity according to ASTM A216 requirements. All pressure-containing parts receive 100% PMI verification using OBLF spectrometers with 0.001% element detection accuracy. Finished valves pass hydrostatic shell testing at 3.0 MPa (1.5 × Class 150 rated pressure) and high-pressure gas seat testing at 2.2 MPa (1.1 × rated pressure) with zero visible leakage. Each valve receives a unique serial number with material certificates, heat treatment records, and test reports traceable for 10 years.
The manufacturing facility holds API 6D monogram license for pipeline valve production. Quality management is certified to ISO 9001:2015 standards. Valves carry CE marking under the Pressure Equipment Directive (PED 2014/68/EU) for European market access. The TS special equipment manufacturing license complies with Chinese pressure vessel regulations. Material declarations confirm REACH and RoHS compliance for restricted chemical substances.
Yes, the valve can be installed in buried pipelines. Extended bonnet options are available for buried service, allowing the handwheel and stem packing to remain accessible above ground level. The carbon steel body can be coated with epoxy or polyurethane for corrosion protection in underground environments.
Flat gate valves with parallel double-disc design provide bi-directional sealing and are less prone to thermal binding at high temperatures compared to wedge gate valves. The floating seat design compensates for pipeline thermal expansion. Flat gate valves are preferred for natural gas transmission pipelines where pigging operations are required, due to the full bore straight-through passage.
Yes, the valve yoke is designed with standard ISO 5211 mounting dimensions, allowing field conversion from handwheel to gear operator or pneumatic actuator without modifying the valve body. Gear operators are recommended for DN250 and larger sizes to reduce operating torque. Pneumatic actuators can be specified for automated pipeline control systems.
