Chapter 5

Identify the system

BASIC HYDRAULIC & PNEUMATIC SYSTEM 2CE 2463

Prepared by:Pn. Zainon Sharmila Shamsuddin

Definition of Pneumatic• Pneumatics is the transmission and control of forces and

movements by means of compressed air. (The use of compressed air as a medium to do work).

Applications of pneumaticsIndustrial applications Pneumatic systems are used in many industrial applications such as:

Material handling � Clamping � Shifting � Positioning � Branching of material flow � Packaging � Filling � Transfer of materials � Sorting of parts � Stamping and embossing of components �

Applications of pneumaticsIndustrial processes Pneumatic systems are used in carrying out machining and some industrial processes such as:

Drilling � Turning � Milling � Sawing � Finishing � Forming�

Some of the pneumatic applications in our life

A Pneumatic machine is used to dismantle an automobile tire

A pneumatic machine is used in an automobile painting

A heavy duty pneumatic jackhammer

A pneumatic filling machine

Some of the pneumatic applications in our life

A dental drill is one of the uses of the pneumatic technology

A pneumatic device is used to fill the tire with compressed air to adjust the tire pressure.

Advantages and disadvantages of pneumatics:

Advantages:

1.Availability: Air is available everywhere in unlimited quantities. 2. Transport: Air can be easily transported in pipelines, even over large

distances. 3. Storage: Compressed air can be stored in a reservoir/tank and removed as

required.4. Temperature: Compressed air is relatively insensitive to temperature

fluctuations.5. Cleanliness: Unlubricated exhaust air is clean.

6.The running cost is relatively inexpensive 7. Speed: Compressed air is a very fast working medium. This enables high

working speeds to be attained. 8.Overload safe: Pneumatic tools and operating components can be

loaded to the point of stopping and are therefore overload safe.

Advantages and disadvantages of pneumatics:

Disadvantages:

1. Preparation: Compressed air requires good preparation. Dirt and condensates should be removed.

2. Speed: As air is compressible; it is difficult to achieve uniform and constant piston speed.

3. Force requirement: Compressed air is economical only up to a certain force requirement. Under the normal working pressure of 600 to 700 kPa (6 to 7 bar).

4. Noise level: The exhaust air is loud (noise). This problem has now, however been largely solved due to the development of sound absorption material and silencers.

Structure and signal flow of pneumatic systems

Pneumatic systems consist of an interconnection of different groups of elements. This group of elements forms a control path for signal flow, starting from the signal section (input) through to the actuating section (output). Control elements control the actuating elements in accordance with the signals received from the processing elements.

Primary levels of the pneumatic system

Primary levels of the pneumatic system

Air generation and distribution• The main function of the air generation and distribution is to provide

the system with compressed air which is dry, clean, and at the required pressure.

• The compressed air supply for a pneumatic system should be adequately calculated and made available in the appropriate quality.

• Air is compressed by the air compressor and delivered to an air distribution system in the factory. To ensure that the quality of the air is acceptable, air service unit is utilized to prepare the air before being supplied to the control system.

• Malfunctions can be considerably reduced in the system if the compressed air is correctly prepared. A number of aspects must be considered.

Preparation of the compressed air:• The following points should be considered in preparing compressed air

plants: 1. Quantity of air required to meet the demand of the system 2. Type of compressor to be used to produce the quantity required 3. Pressure requirements 4. Storage requirements 5. Requirements for air cleanliness 6. Acceptable humidity levels to reduce corrosion and sticky operation 7. Lubrication requirements, if necessary 8. Temperature of the air and effects on the system 9. Line sizes and valve sizes to meet demand 10. Material selection to meet environmental and system requirements 11. Drainage points and exhaust outlets in the distribution system 12. Layout of the distribution system to meet demand.

Pneumatic Circuit Diagram symbols