Calculate bellows-sealed gate valve stem thrust, operating torque and handwheel force — including bellows spring force (f4/f5) and bellows piston effect for zero-leakage glandless designs.
Bellows-sealed gate valves eliminate gland packing leakage, but introduce two additional forces that standard calculators ignore: bellows spring force (proportional to stroke) and bellows piston effect (from pressure acting on the bellows cross-section). Omitting these leads to actuator mis-sizing — a common root cause of bellows valve operational failures.
GG (coeff 0.35) and TG (coeff 0.25) closing force models, same as the non-bellows gate valve calculator.
f4 = kb*(Lb-LGb)/Nb and f5 = kb*LGb/Nb — opening and closing bellows elastic forces from wave stiffness and stroke.
Pressure acting on the bellows inner diameter changes f21/f2 — this calculator uses db_bellows instead of packing gland db.
Built-in database with auto-populated bellows defaults (db, N, k, L, LG) from each thread spec.
Automatic F0/M0 with 30% safety margin, accounting for bellows forces in worst-case scenarios.
Normal and impact rim forces per MSS SP-91 — essential for manual override verification.
Choose Rigid Wedge (GG) or Flexible Wedge (TG).
Input seat bore d, DN, handwheel D, and pressures P1/P2.
Enter bellows inner diameter, wave count, single-wave stiffness, total stroke and closing extension — or use thread spec defaults.
All intermediate forces (including f4/f5), thrust, torque and handwheel forces computed immediately.
Enter your valve parameters below and get instant stem thrust, operating torque and handwheel force results.