Lubricated Plug Valve NPS 4″ Class 150 RF | CF8
NPS 4″ (DN100) Class 150 (PN21) Raised Face Flanged (RF) Inverted Pressure Balanced Lubricated Plug Valve (CF8 Body, Wrench / Lever). Manufactured to API 599 / API 6D and ASME B16.5 RF Flanged. Engineered with dynamic pressure-balancing channels, high-pressure sealant injection grooves, anti-blowout stem assembly, and fire-safe certified metal-to-metal seating for zero-leakage isolation in severe abrasive, slurry, and high-differential hydrocarbon service.
Description
The NPS 4″ (DN100) Class 150 (PN21) Raised Face Flanged (RF) Inverted Pressure Balanced Lubricated Plug Valve (CF8) is an engineered heavy-duty rotary isolation valve manufactured by XIAMEN GUTE VALVE MANUFACTURING COMPANY. Designed in strict compliance with API 599 / API 6D and ASME B16.34, it utilizes an inverted tapered metal plug anchored in a precision-machined body seat pocket. By incorporating dynamic internal pressure-equalizing channels, a high-pressure synthetic sealant injection network, and a fire-safe metal-to-metal seating architecture, it completely eliminates plug wedging and guarantees bubble-tight shutoff across severe abrasive slurries, heavy crude oil manifolds, high-differential gas transmission, and critical petrochemical process pipelines.
Engineering Configuration & Dimensional Specifications
NPS 4″ (DN100) | Class 150 (PN21) | CF8 Body | Raised Face Flanged (RF) | Wrench / Lever | API 599 / API 6D
- Face-to-Face Dimension (L): 229 mm (API 599 / API 6D / ASME B16.5 RF Flanged)
- Centerline-to-Top Stem Height (H): 320 mm
- Operating Breakaway Torque: ~410 N·m (Calculated at full differential shutoff pressure ΔP)
- Bare-Stem Assembly Net Weight: ~54 kg
- Balancing Mechanism: Dynamic inverted pressure balance channels preventing taper taper-lock
- Sealant System: High-pressure button-head injection fitting with internal dual ball check valves
Core Structural Engineering: Dynamic Pressure Balancing & Zero-Cavity Isolation
The inverted plug configuration represents the pinnacle of high-pressure plug valve engineering, resolving the notorious high-torque and jamming vulnerabilities of conventional top-entry plug valves.
- Dynamic Thrust Neutralization: Pressure balance channels transmit line fluid pressure directly to the chamber beneath the inverted plug, counterbalancing downward pressure forces and eliminating taper lock under high differential pressures.
- Seated Surface Protection: When fully open or fully closed, the precision-ground mating surfaces of the plug and body are 100% shielded from direct fluid impingement, preventing particulate erosion and wire-drawing.
- On-Line Hydraulic Unseating: High-pressure lubricant injection creates a micro-film hydraulic jacking action that instantaneously frees the plug even after years of continuous static operation.
Rigorous Quality Assurance & API 6D Testing Protocols
- 1. Positive Material Identification (PMI): 100% Spectro chemical verification on all pressure-retaining casting and forging heats with certified EN 10204 3.1 Mill Test Reports (MTR).
- 2. Hydrostatic Shell Testing: Every individual valve body undergoes high-pressure hydrostatic testing at 1.5x Maximum Allowable Working Pressure (MAWP) per API 598 / API 6D with zero allowable leakage.
- 3. High & Low Pressure Seat Testing: Verified for bubble-tight shutoff (API 6D Rate A zero leakage) under both high-pressure hydrostatic seat closure (1.1x MAWP) and low-pressure air seat test (6 bar).
- 4. Torque & Functional Verification: Measurement of breakaway and running torque under full differential pressure to guarantee actuator compatibility.
- 5. Fire-Safe Certified Construction: Certified compliant with API 607 (7th Edition) and API 6FA fire-safe standards.
Frequently Asked Technical Questions
A: The valve features a heavy-duty button-head sealant injection fitting equipped with an internal double ball check valve. Using a portable hydraulic sealant gun, high-viscosity synthetic lubricant can be injected under full working pressure (up to 10,000 psi). The lubricant flows through precision-machined body channels around the plug perimeter, creating a renewed dynamic fluid seal that instantly seals minor face scratches, lubricates the sliding contact faces, and hydraulically jacks the plug if mechanical taper sticking occurs.
A: The CF8 stainless steel pressure boundary provides complete passivation against aggressive organic acids, sour brine, and chloride solutions. Combined with chemical-resistant fluorosilicone or synthetic hydrocarbon lubricants rated from -40°C to +260°C, the sealing matrix remains completely inert, preventing galling, chemical etching, and localized crevice corrosion.
A: Routine maintenance requires periodic sealant injection tailored to cycling frequency—typically once every 50–100 cycles or every 6 months in static service. During injection, cycling the valve slightly allows the lubricant to distribute evenly across all four vertical body distribution grooves. The stem packing incorporates die-formed flexible graphite rings live-loaded with Belleville washers, ensuring certified low-emission performance per ISO 15848-1 without manual gland retightening.
Need Project-Specific Lubricated Plug Valve Sizing or Actuation Packages?
Contact Gute Valve technical engineering team for certified dimensional drawings, operating torque curves, automated pneumatic/electric actuator sizing, or custom sealant formulations.
Additional information
| Material | |
|---|---|
| Pressure | |
| Valve Size | |
| Connection | |
| Design Standard | ASME Standard |
| Size | NPS 4" |
| Pressure Class | Class 150 |
| Body Material | CF8 |
| End Connection | RF |
| Operation | Lever / Gear / Actuator |
| Design Structure | Inverted Pressure Balance |
| Manufacturer | XIAMEN GUTE VALVE MANUFACTURING COMPANY |
| Plug Material | 304 |
| Seat Material | PTFE (Customizable) |
