Forging new generations of engineers. Pneumatics. Properties of Compressed Air. Components have long working life resulting in longer system reliability Environmentally friendly
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)
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
What possibilities may be on the horizon for pneumatic power?
Could it be human transport?