LESER POSV Type 821 Now Available for Set Pressures Below 2.5 bar-g
The LESER POSV Type 821 Pilot-Operated Safety Valve is a key product in LESER’s international range. Increasingly, customers have requested set pressures between less than 1 and 2.5 bar-g. To address this demand and remain competitive in this range, LESER launched the “POSV 15+ psi-g” project. The aim was to adapt the existing POSV design to allow set pressures below 2.5 bar-g while maintaining technical approval without major design changes. The Type 821 POSV is already approved for a minimum set pressure of 15 psi-g (1.03 bar-g) under ASME standards and 1.0 bar-g under the CE Directive. The design consists of a main valve and a pilot valve, available in Pop Action or Modulate Action versions.
Improved Performance with PTFE Grooved Ring Seals
For set pressures below 2.5 bar-g, the Type 821 Modulate Action POSV meets requirements without design changes. To minimize friction at very low pressures, grooved ring seals made of PTFE are used on the main valve piston guide. The POSV 15+ psi-g project was completed in spring 2024, and the Type 821 Modulate Action POSV is now available for set pressure ranges from 1.0 bar-g to more than 2.5 bar-g.
