GRADE 9 – DESIGN AND TECHNOLOGY
UNIT 6 – PNEUMATICS AND HYDRAULICS
They are used to generate, control and transmit forces to perform mechanical work.
Pneumatic and hydraulic systems are quite similar in their functioning but differ in the
medium used to transmit power.
1. Pneumatic system
In pneumatics, mechanical motion is achieved by using pressurised air that is
obtained by putting air under greater pressure than the air in the general
environment. By compressing air, stored energy is available to produce, transmit and
control movement for operation of pneumatic systems. An air compressor is used to
pressurise and store air.
Uses of pneumatic systems:
• Tyre pumps and gauges
• Road drills
• Jack hammers
• Parking brakes of vehicles
• Paint sprayer
• Automatic doors of vehicles
• Nail guns
• Dentistry equipment
• Impact wrench
2. Hydraulic systems
Hydraulic systems, just like pneumatic systems, are used to generate, transmit and
control energy. However, a hydraulic system is a method of transmitting force or
motion by applying pressure on a confined fluid using a pump. The most frequently
used fluid is OIL as it has lubricating and anticorrosion properties. Hydraulics finds
extensive use due to the following two properties of fluids useful in power
transmission.
1. Fluids cannot be compressed.
2. Fluids have the ability to multiply force.
Working principle of hydraulic systems
A hydraulic system consists of the following essential elements:
1. An oil reservoir: used to store oil
2. A hydraulic pump: used to pressurise oil
3. Control valves: used to control the speed and direction of oil
4. A piston and cylinder: used to produce a linear movement or a hydraulic motor
used to provide rotary motion
5. Pipes or tubing: used to transmit pressurised oil
6. Hydraulic fluid: to transmit power and lubricate the system
Uses of hydraulic systems
• Hydraulic lifts/elevating platforms
• Hydraulic brakes in vehicles
• Hydraulic shock absorbers
• Applications in heavy equipment, e.g. forklifts, cranes and bulldozers.
• Hydraulic jacks
• Presses
• Injection moulding machines
