Lubricated Plug Valve NPS 2″ Class 150 RF | LCB
NPS 2″ (DN50) Class 150 (PN21) Raised Face Flanged (RF) Inverted Pressure Balanced Lubricated Plug Valve (LCB 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 2″ (DN50) Class 150 (PN21) Raised Face Flanged (RF) Inverted Pressure Balanced Lubricated Plug Valve (LCB) 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 2″ (DN50) | Class 150 (PN21) | LCB Body | Raised Face Flanged (RF) | Wrench / Lever | API 599 / API 6D
- Face-to-Face Dimension (L): 178 mm (API 599 / API 6D / ASME B16.5 RF Flanged)
- Centerline-to-Top Stem Height (H): 225 mm
- Operating Breakaway Torque: ~135 N·m (Calculated at full differential shutoff pressure ΔP)
- Bare-Stem Assembly Net Weight: ~20 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: In standard plug valves, line pressure forces the tapered plug deeper into the body seat pocket, resulting in excessive operating torque and taper wedging. In Gute inverted pressure-balanced plug valves, the plug is positioned inverted with an upper balancing port connecting line pressure to both top and bottom chambers. Pressure equalization across both ends neutralizes axial hydraulic thrust, maintaining operating breakaway torque at a predictable ~135 N·m and enabling fast quarter-turn manual operation even under maximum line differential pressure.
A: Yes. When ordered for sour service, Gute manufactures this valve in strict compliance with NACE MR0175 / ISO 15156. The LCB carbon steel casting undergoes controlled heat treatment to limit base metal and weld hardness to <= 22 HRC. The plug is surface-hardened with Electroless Nickel Plating (ENP >= 75 µm) or supersonic Tungsten Carbide (TCC), and fasteners conform to ASTM A193 B7M/2HM, preventing sulfide stress cracking (SSC) and hydrogen embrittlement in wet H2S environments.
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 2" |
| Pressure Class | Class 150 |
| Body Material | LCB |
| End Connection | RF |
| Operation | Lever / Gear / Actuator |
| Design Structure | Inverted Pressure Balance |
| Manufacturer | XIAMEN GUTE VALVE MANUFACTURING COMPANY |
| Plug Material | F6a |
| Seat Material | PTFE (Customizable) |
