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Sempell Model VS99 Pilot Operated Safety Valve
Sempell VS99 Pilot Operated Safety Valve
Operated by steam pilots VS66 and/or solenoid pilots EMS.
Medium operated safety valve for extra large capacities
Preferred solution for Russian GOST boiler applications
Sempell Model VS99 Pilot Operated Safety Valve


Size Inlet:
DN 80 – DN 750
NPS 3 – NPS30
Welding end
Up to 600°C / 1100°F
Set pressure:
5 bar – 320 bar
Orifice diameter:
44 mm – 438 mm
Body material:
1.7335/SA182 F12
1.7380/SA182 F22
Position indicator, vacuum spring


  • High Tightness, because system pressure acts in closing direction
  • Small opening and closing pressure differences
  • Blow down widely adjustable
  • High setting accuracy and reproducibility
  • Function nearly independent from pressure losses in connected pipes
  • Opening of the safety valve also below set pressure possible
  • Test setting of safety valve during normal plant operation
  • Test of the control function without opening of the safety valve