American manufacturer Curtiss-Wright’s Industrial Division has announced that its business unit Farris Engineering will now offer restricted lift on its 2600 and 2600L Series API-type pressure relief valves. The restricted lift option is available on orifice sizes D-Z for compressible service for both new 2600 Series valves and as a retrofit option for Farris’ in service valves.
ASME Code Section VIII and API 526 both provide for certification and use of a restricted lift design for relief valves. Farris’ design option allows operators to customize the valve lift to meet their specific capacity requirements. ASME code requires that restriction should be not less than 30% of the PRV’s full rated lift or less than 0.080 inches.
The benefits of using a restricted lift valve for operators is that they can more closely match the pressure relief valve’s flow capacity to their system’s required capacity. Restricted lift can improve a valve’s performance and stability especially in larger orifice size valves. Pressure relief valves with a restricted lift option are also a cost effective solution for situations where PRV’s experience inlet pressure losses in excess of 3% of set pressure.
Image courtesy Curtiss-Wright