Pilot-operated gas pressure regulator · P1 100 bar → P2 10 bar

Reflux 819 Regulator Simulator

Click Increase or Decrease flow and watch the loop: outlet pressure deviates, the pilot changes the motorization pressure, the piston moves, and the outlet returns to the set point. Zero flow shows lock-up.

piston P2 + spring (close) Pm (open) orifice in diaphragm (Pm ↔ P2 equalizing) Pre-regulator Pilot set 10.0 bar set screw ↓ P1 100.0 bar 20.0 bar Pm 11.00 bar P2 10.00 bar Opening 20.0 % INLET OUTLET

Piston & seat · close-up

OUTLET INLET 100 bar 20.0 % open
Outlet P2
10.00bar
set point 10.00
Motorization Pm
11.00bar
Pm − P2 = 1.00
Piston
20.0% open
steady
Flow
10,000Nm³/h
demand 10,000
Inlet P1
100.0bar
upstream supply
Pilot supply
20.0bar
after pre-regulator

End-client flow

Pilot set screw 10.0 bar

Control sequence

Stable.

Trend · last 40 s

Regulator flow Demand Outlet P2 Motorization Pm Piston opening

Event log

  1. Each flow change is logged here with the P2 peak, Pm swing and piston travel.

Model basis

  • P1/P2 = 10, so flow through the seat is choked and depends on piston opening only.
  • Opening-to-flow curve fitted to your two points: 20 % → 10,000 and 30 % → 12,000 Nm³/h.
  • Actuator: opening = 20 % per bar of (Pm − P2). Pm 10.1–12 bar spans ≈2–40 % travel.
  • Pilot: P2 under the pilot diaphragm against the set-screw spring. Low P2 opens it (blue 20 bar → orange Pm); high P2 closes it and Pm bleeds to P2 through the orifice in the main diaphragm.
  • Zero flow: pilot shut, orifice equalizes Pm = P2, spring closes the piston. Closing pressure here ≈10.2–10.3 bar; Fiorentini lists lock-up class up to SG 2.5 (≤10.25 bar at 10 bar set).
  • Illustrative dynamics, not vendor data.