Audco Lift Type NRV Valve
Audco Lift Type NRV Valve: Technical Overview & Specifications
The Audco Lift Type NRV (Non-Return Valve), manufactured under L&T Valves, is an automatic backflow prevention valve designed to permit fluid flow in one direction and instantly check backflow to protect upstream pumps, compressors, and equipment. It is widely used in high-pressure systems handling water, oil, gas, steam, and chemical process fluids.
Technical Specifications & Standards
- Design Standards: Conforms to BS 5352 / API 602 for forged variants and BS 1868 / API 6D for larger cast models.
- Body Design: Bolted body-cover (bonnet) construction featuring a renewable seat and disc structure.
- Size Range: 1/4" to 2" (DN15 to DN50) for forged lines; up to 12" (DN300) for cast lines.
- Pressure Classes: Available in ASME Class 150, 300, 600, and 800 ratings.
- Testing Integrity: Tested and verified per API 598 inspection standards for shell and seat tightness.
Material of Construction (MOC)
|
Component Category |
Material / Grade |
Typical Service Conditions |
|
Forged Carbon Steel |
ASTM A105 |
Class 800 high-pressure utility lines. |
|
Cast Carbon / Stainless Steel |
WCB, CF8 (SS304), CF8M (SS316) |
Corrosive process fluids and general plant utilities. |
|
Alloy Steel |
F5, F9, F11, F22 |
Elevated temperatures (up to $427^\circ\text{C}$) and high-pressure steam service. |
|
Trim & Seating |
Stainless Steel or Stellite hard-faced Alloy Steel |
Durable metal-to-metal seating resistant to erosion. |
Working Mechanism
- Flow Opening: Upstream fluid pressure forces the internal disc or piston to lift vertically off the seat, opening the passage.
- Backflow Closure: Gravity, along with reverse line pressure (or an optional internal spring), forces the disc down onto the seat as soon as forward flow ceases.
- System Protection: Creates a rapid, tight seal against reverse pressure waves to prevent pump damage.
End Connections
- Flanged Ends: Standard ASME, BS, or DIN flanges for bolt-on installation.
- Socket Weld (SW) & Screwed NPT: Threaded or welded options engineered for leak-free, high-pressure forged steel pipelines.
