Jacketed pressure relief valves
Luofu LFNJ valves have a steam or heat transfer oil jacket that keeps the inlet and outlet warm. The heat stops crystallizing media from blocking the seat and keeps viscous media flowing. Inlet sizes run from NPS 1 to 10 (DN25 to DN250). Pressure ratings run from Class 150 to Class 2500 with ASME flanges, or PN10 to PN420 with PN flanges. The temperature range is -46 to +538 °C (-51 to +1,000 °F).
Where it is used
Choose a jacketed valve for media that crystallize or turn thick as they cool. Without heat, the medium can build up on the seat and the disc and stop the valve from opening or reclosing.
Steam or heat transfer oil flows through a jacket around the body and keeps the valve warm between relief events.
Technical data
- Series
- LFNJ jacketed, balanced bellows
- Inlet size
- NPS 1 to 10 (DN25 to DN250)
- Orifice
- Letters D to V, 1"D2(2.5)" to 10"V14(16)"
Size code as we publish it - Pressure rating
- Class 150 to Class 2500 ASME flanges
PN10 to PN420 PN flanges - Temperature range
- -46 to +538 °C (-51 to +1,000 °F)
- Set pressure
- Confirmed in the sizing for each tag number
- Jacket medium
- Steam or heat transfer oil
- Jacket rating
- Class 150 or PN16
- Jacket connections
- NPT female thread as standard, socket weld or flanged as options
- Bellows
- Balanced bellows
- Special trim materials
- 316LN, F51, F53, F55
These are the limits of the series. The limits of one valve depend on its size, rating, and materials. The sizing confirms them for each tag number. The Class range and the PN range are the ranges we offer with ASME flanges and with PN flanges. One is not a conversion of the other.
Structure
The jacket surrounds the body and forms a space for the heating medium. The jacket connections are NPT female threads as standard, with socket weld and flanged connections as options. The jacket is rated Class 150 or PN16.
A steam purge port is an option for clearing deposits from the seat area.
Options
Choose these at the inquiry stage. The sizing confirms which ones apply to your tag:
- Steam purge port
- Socket weld or flanged jacket connections
- Special trim in 316LN, F51, F53, or F55
Standards and certifications
The ASME, National Board, and TS documents cover Luofu's production of relief valves. The quotation states which of them apply to each tag:
What we need to quote this valve
Send these with your inquiry. A completed data sheet covers all of them, and the PSV data sheet page explains each line:
- Medium and phase (gas, vapor, liquid, or two-phase)
- Required relieving capacity
- Set pressure
- Back pressure at the outlet
- Operating and relieving temperature
- Jacket medium, with its pressure and temperature
- Inlet and outlet size and rating
- Material requirements
- Design code (ASME, API, EAC, or the project specification)
- Quantity, per tag number
- Project country
No data sheet yet? Send what you have. We ask for the rest by email.
Related series
Questions engineers ask
Steam or heat transfer oil: which jacket medium should I use?
Use the heating medium the plant has at the temperature the process medium needs. Give its pressure and temperature on the data sheet, and we check them against the jacket rating of Class 150 or PN16.
Why does a jacketed valve have a bellows?
The bellows balances back pressure, so the set pressure stays steady when the outlet pressure changes. It also keeps the medium away from the spring and the guide, which matters with media that crystallize.
Which trim materials are available for corrosive service?
Special trim is available in 316LN, F51, F53, and F55. The sizing confirms the trim from the medium and the temperature.