IFPS CFPS cheat sheet

Pressure p = F/A; gauge pressure is measured relative to atmosphere, absolute pressure = gauge + atmospheric.

Pascal's principle: pressure applied to a confined fluid transmits undiminished in all directions, enabling force multiplication in hydraulic cylinders.

Hydraulic force multiplication: F2 = F1 × (A2/A1); a larger piston area yields greater force but proportionally shorter stroke for equal volume.

Flow rate Q = A × v; for a given flow, velocity increases as conductor area decreases (continuity equation).

Fluid power power: P = p × Q; in SI, watts = pascals × cubic meters per second; in US units, horsepower = (psi × gpm)/1714.

Torque from a hydraulic motor: T = (p × Dm)/(2π) in consistent units, where Dm is displacement per revolution.

Boyle's law for gases: p1V1 = p2V2 at constant temperature; Charles's law relates volume to absolute temperature at constant pressure.

Standard atmospheric pressure ≈ 101.3 kPa ≈ 14.7 psi ≈ 1.013 bar; vacuum is often expressed relative to this baseline.

Energy is conserved in fluid systems; losses appear as heat from friction, throttling, and leakage, not as destroyed energy.

Hydraulic systems transmit force via incompressible fluid; typical operating pressures range from ~70 bar (1000 psi) to over 350 bar (5000 psi).

Cylinder extend force = p × A_bore; retract force = p × (A_bore − A_rod), so retract force is lower for the same pressure.

Cylinder speed = Q/A; extend speed uses full bore area, retract speed uses annulus area, so retract is faster for equal flow.

Relief valve limits maximum system pressure and protects components; it is a normally closed, pressure-actuated valve that bypasses flow to tank.

Directional control valve center conditions: closed center blocks all ports, tandem center connects pressure to tank while blocking work ports, float center connects work ports to tank.

Flow control valves meter flow; meter-in controls actuator speed on extend, meter-out controls speed on retract and resists overrunning loads, bleed-off diverts excess flow.

Accumulators store pressurized fluid energy; bladder and piston types are common, and precharge is set below minimum working pressure.

Filtration is rated in microns (absolute vs nominal); beta ratio βx(c) describes the ratio of particles upstream to downstream at size x.

Hydraulic fluid functions include power transmission, lubrication, sealing, cooling, and contamination transport; ISO VG grade denotes viscosity at 40 °C.

Pneumatic systems use compressible air; force = p × A but pressure varies with load and flow, so force is not constant during stroke.

Standard free air delivery (FAD) is referenced to standard conditions; actual cylinder air consumption = piston area × stroke × cycles × (absolute working pressure / atmospheric pressure).

Air compressors: positive displacement (reciprocating, rotary screw, vane) vs dynamic (centrifugal); rotary screw dominates industrial continuous duty.

Air preparation unit (FRL): filter removes water and particles, regulator sets pressure, lubricator adds oil mist downstream.

Pneumatic cylinder force: extend F = p × A_bore; retract F = p × (A_bore − A_rod); subtract friction for effective force.

Speed control in pneumatics is usually meter-out because air compressibility makes meter-in unstable with overrunning loads.

Air dryers: refrigerated dryers reach dew points around +3 °C; desiccant dryers reach −40 °C or lower for critical applications.

Pneumatic logic elements include directional valves (3/2, 5/2), shuttle (OR), and dual-pressure (AND) valves; ISO 1219 symbols identify ports 1, 2, 4, 5.

Solenoid-operated directional valves use single or double solenoids; double-solenoid valves require detents or spring return and often a memory function.

Proportional and servo valves convert electrical input (current or voltage) to controlled flow or pressure; proportional valves trade accuracy for cost.

LVDT (linear variable differential transformer) provides position feedback on proportional and servo valves for closed-loop control.

PLC output types: relay, transistor (sourcing/sinking), and triac; transistor outputs switch DC fast, relays handle AC and higher currents.

Sinking (NPN) sensors switch the load to ground; sourcing (PNP) sensors switch the load to positive supply; the PLC input type must match.

Electrical power in DC: P = V × I; in AC single-phase: P = V × I × power factor; three-phase: P = √3 × V × I × power factor.

Safety standards: ISO 13849-1 uses Performance Levels (PL a–e); IEC 62061 uses Safety Integrity Levels (SIL 1–3); emergency stop must be a category 0 or 1 stop per ISO 13850.

Hysteresis, deadband, and null offset are key valve specifications; null shift causes drift in proportional valve control.