Forging new generations of engineers. Pneumatics. Properties of Compressed Air. Components have long working life resulting in longer system reliability Environmentally friendly
Tool used by blacksmiths and smelters for working iron and other metalsEarlyPneumaticUses
Showed that a vacuum can be created
Created hemispheres held together by atmospheric pressureEarlyPneumaticUses
Designed by Alfred Beach
Built in New York City
Completed in 1870
312 feet long, 8 feet in diameter
Closed in 1873EarlyPneumaticUses
Gauge Pressure: Pressure on a gauge does not account for atmospheric pressure on all sides of the system
Absolute Pressure: Atmospheric pressure plus gauge pressure
Gauge Pressure + Atmospheric Pressure =
Pressure (P) is measured in pounds per square inch
- lb/in.2 or psi
Standard atmospheric pressure
- 14.7 lb/in.2
Example: If a gauge reads 120.0 psi, what is the absolute pressure?
120.0 lb/in.2 + 14.7 lb/in.2 = 134.7 lb/in.2
0°F and 0°C don’t represent TRUE ZERO°
Absolute Zero = -460°F or -273°C
Absolute Temperature is measured in
degrees Rankine (°R = °F + 460 °) <- English/Std.
degrees Kelvin (°K= °C + 273 °) <- Metric
Example: If the air temperature in a system is 65 °F what is the absolute temperature?
65 °F + 460. = 525 °R
The pressure of a given mass of gas is inversely proportional to its volume (providing the gas remains at constant temperature)
Isothermic (equal temperature)
Properties of GasesCharles’s Law
When the pressure of a confined gas remains constant, the volume of the gas is directly proportional to the absolute temperature.
Isobaric - equal pressure
V1 = initial volume
V2 = resulting volume
T1 = initial absolute temperature
T2 = resulting absolute temperature
A volume of air in an accumulator is submerged in a bucket of ice water (32 degrees F). If you remove the accumulator from the ice water and place it in a bucket of boiling water what would the resulting volume be.
Absolute is 460 +
V2 = V1x 672
V2 = V1 x T2
When the volume of a confined gas remains constant, the pressure of the gas is inversely proportional to the absolute temperature.
Ideal Gas Law
Combining the work of Charles, Gay-Lussac, and Boyle we obtain:
Which was the main precursor to the modern day ideal gas Law:
Pressure exerted by a confined fluid acts undiminished equally in all directions.
Pressure: The force per unit area exerted by a fluid against a surface
Pascal’s LawPascal’s Law Example
How much pressure can be produced with a 3 in. diameter (d) cylinder and 50 lb of force?
d = 3 in. p = ?
F = 50 lb A = ?
Directional Control Valve
Pressure Relief Valve
CompressorCommon Pneumatic System Components
National Fluid Power Association & Fluid Power Distributors Association
What possibilities may be on the horizon for pneumatic power?
Could it be human transport?