Rod Load, Frame Load & Operating Envelope
| Parameter | Formula |
|---|---|
| Head End Area | AHE = π/4 × bore² |
| Crank End Area | ACE = π/4 × (bore² - rod²) |
| Gas Compression Load | Pd × AHE - Ps × ACE |
| Gas Tension Load | Ps × AHE - Pd × ACE |
| Inertia Load(θ) | -Mrecip·ω²r(cos θ + (r/L)cos 2θ)/gc |
| Combined Load(θ) | Fgas(θ) + Finertia(θ) (algebraic sum) |
| Volumetric Efficiency | 0.97 - 0.04 - Cl × ((Pd/Ps)1/k - 1) |
Understand compressor loading analysis, rod load calculations, and operating envelope evaluation
It calculates rod loads, frame loading percentages, cylinder pressures, volumetric efficiency, and capacity for reciprocating compressors at specified operating conditions.
Rod loads must stay within the frame rating to prevent structural damage. Both compression and tension rod loads must be checked, along with adequate rod reversal for bearing lubrication.
Unloading the head end or crank end removes that end's contribution to compression work, reducing capacity and changing the rod load balance. This is used for capacity control and to manage loading at different operating pressures.