API 600 Class 900 Gate Valve (OS&Y Bolted Bonnet, Flexible Wedge)
Supreme Valves' API 600 Class 900 Gate Valve is a heavy-duty, high-pressure wedge gate valve engineered for refineries, power steam generation, and petrochemical piping. Utilizing an Outside Screw & Yoke (OS&Y) design with a bolted bonnet, flexible wedge, and standard 13Cr trim for robust high-velocity isolation. NACE MR0175 compliant.
Key Applications
Industrial Applications & Engineering Problem Solving
The Engineering Challenge
High-pressure, high-temperature steam pipelines in power turbines and chemical reactors suffer from 'thermal binding'. When a solid gate valve is closed hot, subsequent cooling causes the piping to contract, pinching the wedge between the seats. This mechanical lockup makes the valve impossible to reopen without extreme torque, risking actuator motor damage or stem rupture.
The Supreme Valves Engineering Solution
This valve incorporates a Flexible Wedge design, which features a central groove that allows the wedge halves to flex under high piping loads, preventing thermal binding. The backseat is hardfaced with Stellite 6 alloy to resist high-velocity steam erosion, while the Bolted Bonnet Outside Screw & Yoke (OS&Y) design keeps wetted steam away from the stem threads for lifetime reliability.
Operational Use Cases & Scenarios
Superheated High-Pressure Steam Main Isolation
Operational Challenge: Isolating superheated steam at 540°C and Class 900 rating without suffering wedge lockup or steam erosion.
Engineering Benefit: Stellite hardfacing prevents steam-wire drawing, and the flexible wedge absorbs piping contraction.
Reactor Recycle Loop Gas Isolation
Operational Challenge: Isolating hot, high-pressure hydrogen recycle loops containing hydrogen sulfide (H2S).
Engineering Benefit: NACE MR0175 compliance prevents hydrogen-induced stress cracking, ensuring safe, long-term operation.
Technical Specifications
Material of Construction (MOC)
Purchase Options
Features & Benefits
API 600 Heavy Wall
Heavy-duty wall thickness exceeds API 600 requirements, providing long structural life under thermal cycles.
Stellite Hardfaced Seats
Seat surfaces are hardfaced with Stellite 6 alloy to resist high-velocity steam erosion and particle abrasion.
Flexible Wedge Design
Flexible wedge prevents mechanical binding (thermal binding) in high-temperature steam lines.
Leak-Free OS&Y Stem
Outside Screw & Yoke design prevents the wetted fluid from contacting the stem threads, ensuring long thread life.
Frequently Asked Questions
Q What is thermal binding in gate valves?
When a solid gate valve is closed hot and the piping cools down, the contraction can pinch the wedge so hard it becomes jammed. Our flexible wedge design absorbs this piping contraction to prevent binding.
Q What is the benefit of OS&Y design?
OS&Y keeps the stem threads outside the wetted valve cavity. This prevents lubricating grease from washing out and keeps high-temperature steam or corrosive hydrocarbons away from wetted threads.
Q Can this valve be motorized?
Yes, all our Class 900 gate valves can be fitted with electric actuators (Rotork, Auma) or spur-gear manual operators for large sizes.