Pneumatics — validation & limitations

What it calculates

• Cylinder bore sizing against the ISO 15552 bore series — advance and retract force, back-pressure on the exhausting chamber, safety factor vs. load
• ISO 6358 valve flow sizing — Cv, Kv, sonic conductance C, and automatic choked-flow detection (P2/P1 < b, sized at the lowest b in the port table)
• Compressed-air system demand — total and peak flow, diversity factor, receiver volume and compressor power (engineering estimate)
• Actuator stroke-time and tube-velocity analysis with high-velocity warning
• FRL (Filter-Regulator-Lubricator) port selection from a catalogue flow table
• Compressed-air cost and leak audit with payback analysis

Standards this tool applies

• ISO 1219 — Calculate cylinder bore, advance and retract force, valve Cv/Kv and sonic conductance for the pneumatic actuators and valves documented in the schematic.
• ISO 6358 — ISO 6358-1 sonic-conductance valve sizing (choked/subsonic flow, C, and ideal-nozzle Cv/Kv equivalents) with a next-size pick from the tool's own typical port table and Cv series; also cylinder force and system air demand (screening; ISO 15552 / ISO 4414 are not checked).

Validation evidence — independent reference cases (2)

Each case runs the tool's engine on a worked example whose values come from a published source or a hand derivation from the cited equations, and an automated regression test asserts the engine against those values within the stated tolerance. "Conservative" means the engine is known to sit on the safe side of the reference and the test asserts that side. Sources are cited; their text is not reproduced.

• Cylinder force, load safety factor and free-air consumption

  Agrees

  Source: Hand derivation F = p·A (the form maker catalogue force tables for ISO 15552 cylinders tabulate); pneumatics-maker free-air consumption formula (isothermal)

  Inputs: Double-acting, D 50 mm, d 20 mm, stroke 200 mm, 6 bar g, friction 0.10, load 600 N, 10 cycles/min

  Quantity	Reference value	Tolerance
  theoretical force advance / retract	1178.10 N / 989.60 N	1e-6 relative
  load safety factor advance / retract	1.7671 / 1.4844	1e-6 relative
  free air per cycle / flow	5.0023 L / 50.023 L/min	1e-6 relative

  tests/golden/REF-pneumatics-cylinder-force-air.golden.test.ts

• Receiver draw-down volume and compressor power

  Agrees

  Source: compressed-air handbook (receiver sizing; isothermal compression power); CAGI compressed-air handbook; hand derivation

  Inputs: Consumers 1000 Nl/min at 50 % and 600 Nl/min at 100 %; 7 bar g; band 1 bar; on-load 50 %; installed receiver 500 L

  Quantity	Reference value	Tolerance
  required receiver volume	1337.16 L	1e-6 relative
  isothermal compressor power	7.6828 kW	1e-6 relative
  required volume at 40 % on-load, band 0.5 bar	4011.48 L	1e-6 relative

  tests/golden/REF-pneumatics-receiver.golden.test.ts

Limitations

Not checked by this tool

• Cylinder: end-of-stroke cushioning and kinetic energy at the stop — Not modelled; check the moving mass and speed on the maker's cushioning diagram or add shock absorbers
• Cylinder: side load, gland clearance and misalignment on the rod — Not modelled; keep side loads off the rod or use a guided cylinder
• Cylinder: rod-end thread, rod eye and mounting / pivot strength — Use the maker's data for the rod end and mounting at the stall thrust
• Cylinder: the gravity-assisted lowering stroke of the load builder — The load builder models the raising stroke; check the lowering speed control (meter-out) separately
• Rodless cylinder: carriage load and moment capacity — Use the manufacturer's data
• Vacuum pads: horizontal traverse acceleration (pads in shear) — Only vertical lift acceleration is applied; size horizontal moves with the vendor's method
• Air quality and condensate (ISO 8573-1) — The class selector is reference only; size dryers and filters with the supplier