Total stem torque: M = MM+MC+Mu+MT+MO. Ball seal friction MM = FQ·R·μM·(1+cosα)·cosα, bearing MC, packing MT, O-ring MO, double-seat force chain.
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M = MM+MC+Mu+MT+MO covers every friction source in the valve.
MM = FQ·R·μM·(1+cosα)·cosα exact spherical contact model.
MC from full seat loop axial thrust on self-lubricating bushing.
DIB double isolation: FQ = FZJQ + 2Fn + FMM.
MT with packing factor ψ=1.2, MO for 3 O-rings.
Compares against stem max allowable torque 4772 N·m.
Enter pressure and seat/ball geometry.
Set all friction coefficients μM, μC, μT, μO.
Journal, thrust pad, packing, O-rings.
Compare total M with allowable Mmax.
Enter your design parameters and get instant verification results.
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