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Laws governing pneumatic systems

Week 5 3_gas_laws_and_into_to_pneumatics

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Laws governing pneumatic systems

Boyle’s Law

Gay-Lussac’s Law

Charles’ Law

GENERAL GAS LAW

Temperature constant

Volume will change inversely with absolute pressure

Pressure constant

Volume will change inversely with absolute temperature

Volume constant

Pressure will change inversely with absolute pressure

Combination of Boyle’s, Charles’, Gay-Lussac’s Law

No parameter is held constant

Remember, all are expressed in ABSOLUTE terms, not GAUGE terms!

Gas at 6.895 × 106 Pa and 38 °C is contained in the 50.8 m3 cylinder as shown below. A piston compresses the volume to 38.1 m3 while the gas is heated to 93 °C. What is the final pressure in the cylinder?

Ans: 1.09 × 107 Pa

Definition: The use of compressed air in order to generate force that can produce mechanical movement

Pneumatics has been used for carrying out mechanical tasks for a long time

Important applications: ◦ Determine the status of processors (sensor) ◦ Switching of actuators by means of final control

elements ◦ Carrying out work (actuators)

Advantages of pneumatics ◦ Raw material freely available ◦ Easily transportable and stored ◦ Can be used in high temperatures ◦ Clean ◦ Fast ◦ Explosion proof ◦ Parts are easy to design & build

Disadvantages ◦ Preparation ◦ Compression ◦ Force limitations ◦ Noise

Drilling

Milling

Sawing

Finishing

Forming

Stamping

Embossing

etc

The product development in pneumatics can be considered in number of:

◦ Actuators

◦ Sensors and output devices

◦ Processors

◦ Accessories

◦ Control systems

Factors in development of pneumatics control system: ◦ Reliability and safety of operation ◦ Ease of maintenance ◦ Cost (economy, spare parts, etc) ◦ Assembly and connection ◦ Interchangeability and adaptability ◦ Compact design ◦ Operation efficiency