L&T Pressure Seal Check Valve
Ultimate Technical Guide to L&T Pressure Seal Check Valves: Specifications, Features & Applications
In critical high-pressure power generation and industrial steam systems, backflow prevention requires exceptionally robust valves that can withstand extreme pressures and fluid velocities. L&T Pressure Seal Check Valves (manufactured by L&T Valves) are non-return valves (NRVs) engineered to provide automatic, fast-acting backflow protection without risking body-bonnet joint leakage under thermal cycling.
Technical Specifications Summary
|
Feature |
Specification Details |
|
Size Range |
2" to 24" (DN50 – DN600) |
|
Pressure Ratings |
ASME Class 900, 1500, 2500, and 4500 |
|
Design Standards |
ASME B16.34, BS 1868, API 6D |
|
Testing Standards |
API 598, BS EN 12266-1 |
|
End Connections |
Butt Weld Ends (ASME B16.25) and Flanged Ends (ASME B16.5) |
|
Valve Configurations |
Swing Check, Piston/Lift Check, and Tilting Disc Check |
Material Construction & Trim Options
- Cast Carbon Steel: ASTM A216 Grade WCB / WCC (standard high-pressure service).
- Cast Alloy Steel: ASTM A217 Grade WC6, WC9, C12A (engineered for high-temperature superheated steam).
- Stainless Steel: ASTM A351 Grade CF8M / CF3M.
- Hardfacing & Seat Trim: CoCr-A (Stellite 6) hardfaced body seats and disc seating faces to prevent galling, pitting, and high-velocity erosion.
Key Engineering Advantages
- Pressure-Assisted Sealing: Utilizes internal pipeline pressure to tighten the body-bonnet joint against the pressure seal gasket, eliminating potential bonnet joint leaks under high pressures.
- Smooth Full-Bore Flow Path: Minimizes flow resistance, pressure drop, and turbulence through the body cavity.
- Rapid Non-Slam Closing: Tilting disc and piston configurations feature balanced weight profiles and optional dashpots to ensure rapid response to flow reversals, preventing water hammer.
- In-Line Maintainability: Built with guided discs and removable hinge assemblies to facilitate easy maintenance and inspection during plant turnarounds.
Primary Industrial Applications
- Thermal & Fossil Power Plants: Boiler feed pump discharge, main steam lines, reheater cold lines, and superheater drains.
- Combined-Cycle (HRSG) Units: High-pressure steam boiler loops and feed water isolation systems.
- Refining & Hydrocarbon Processing: High-pressure hydrotreater feed lines, hydrogen service, and synthetic gas handling.
