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Basic Pneumatics. Introduction. Air has existed since the beginning of time. Man has harnessed the power of the wind to power many devices. Only in the last century has man used air as power transmission medium. Use air under pressure Is a low power system
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Basic Pneumatics ms4.18 Basic Pneumatic System/Tieh SF
Introduction • Air has existed since the beginning of time. Man has harnessed the power of the wind to power many devices. Only in the last century has man used air as power transmission medium ms4.18 Basic Pneumatic System/Tieh SF
Use air under pressure Is a low power system Transmitting medium is compressible Leaks are clean Components are lighter and less expensive Air is cheap Pneumatics System ms4.18 Basic Pneumatic System/Tieh SF
Applications of Pneumatic System • Industrial robots (Automation) • Operation of bus doors • Operation of machine tools • Operation of work holding devices • Air tools ms4.18 Basic Pneumatic System/Tieh SF
Explosion proof Fast Easily transportable Easily stored Overload safe Variable speed Variable pressure Clean Simple construction Stroke setting No return lines Wide operating temperatures Others (compact,light,repair) Benefits of Compressed Air ms4.18 Basic Pneumatic System/Tieh SF
Intake air filter Compressor After cooler Air separator Pressure switch Safety valve Air Receiver Air service unit Directional valves Actuators A Basic Pneumatics System ms4.18 Basic Pneumatic System/Tieh SF
Filter element Drain FILTER Pneumatic components • Air filter with water separator • To filter dirt and moisture from the air line ms4.18 Basic Pneumatic System/Tieh SF
It takes in atmospheric air. Compresses the air so as to increase the air pressure. Transfers the compressed air into an air receiver. Air Compressor ms4.18 Basic Pneumatic System/Tieh SF
Detailed representation Pressure gauge Filter Lubricator Pressure regulating valve Pneumatic components • Air Service Unit • Air filter with water separator • Pressure regulator with pressure gauge • Oil mist lubricator Simplified representation ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic components • Pressure Regulator • To reduce the air supply pressure. • To keep the outlet pressure constant even if the outlet air supply pressure fluctuates. • Input (Inlet) pressure must be greater than the output pressure. ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic components • Pressure Regulator ms4.18 Basic Pneumatic System/Tieh SF
Oil mist Oil Venturi tube Drain LUBRICATOR Pneumatic components • Oil mist lubricator (Lubricator ) • To provide oil mist in the compressed air so as to lubricate the pneumatic components • Reduce wear of component • Protect from corrosion ms4.18 Basic Pneumatic System/Tieh SF
System pressure To atmosphere Outlet to Atmosphere System pressure Pneumatic components • Pressure Limiting Valve ( Safety Valve ) • To prevent the maximum permissible pressure in a system from being exceeded Pressure relief valve adjustable ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic Valves • Flow control valve (throttle relief valve) • air flow is throttled in one direction only • check valve blocks the flow in one direction and the air can only pass through the restricted passage • check valve allow the reversed air to by pass the restricted passage • use for speed regulation ms4.18 Basic Pneumatic System/Tieh SF
Air blocked this direction must go through restriction 1 2 3 p1 4 5 8 p2 6 7 7 Pneumatic Valves • Throttle relief valve Symbol to ISO 1219 ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic Valves • Two pressure valves (AND element) • compressed air flows through only if signals are applied to both inlets • the signal which is last applied passes to the outlet • for 2 different input pressure, the smaller pressure will pass to the outlet • for interlocking and safety control, check function or logic operation ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic Valves • Check valve • stop flow completely in one direction • allow full flow in another direction • blocking element can be cones, balls, plates or diaphragms ms4.18 Basic Pneumatic System/Tieh SF
1 2 1 3 4 Pneumatic Valves • Variable flow control valve • (adjustable designed by arrow) Symbol to ISO 1219 ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic Valves • Shuttle valve (OR element) • this is called double control valve or double check valve • air flows to the outlet if pressure is applied to any of the 2 inlet • the pressure which is first applied will flow to the outlet ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic Valves • Quick exhaust valve • used to increase the piston speeds in cylinders • particularly useful for single acting cylinder ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic Valves • Sequence Valve • acts as pressure switch where a specific pressure is required for a switching operation. ms4.18 Basic Pneumatic System/Tieh SF
Z Z R R A A P P Normally closed time delay Pneumatic Valves • Time Delay Valve ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic Valves • Directional Control Valves • Examples : 2/2, 3/2, 4/3 way valves • To control start, stop, and directional of air flow so that the cylinder’s movement can be controlled • Start or stop, forward or reduce stroke, clockwise or anti-clockwise rotation of an air motor ms4.18 Basic Pneumatic System/Tieh SF
A a b P A b a R P Examples: A) Simplest valve: shut-off valve 2 connections 2 positions ( squares ) produces a 2/2 way directional control valve. B) 3 connections 2 positions ( squares ) produces a 3/2 way directional control valve. ms4.18 Basic Pneumatic System/Tieh SF
B A a b P R B A a b P R R C) 4 connections 2 positions ( squares ) produces a 4/2 way directional control valve. D) 5 connections 2 positions ( squares ) produces a 5/2 way directional control valve. ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic Lines & Fittings • Transfer the compressed air to different components • Flexible hoses and quick-disconnect couplings are more suitable for equipment which require couple or un-coupled frequently ms4.18 Basic Pneumatic System/Tieh SF
Pneumatic Lines & Fittings • Things to look into when installing • correct dimension of pipes • regular maintenance and checking • pipelines are installed at a downward gradient of 1 to 2 % • main line should be installed as a ring circuit where space is available • should be easy to install, resistant to corrosion and inexpensive ms4.18 Basic Pneumatic System/Tieh SF
Advantages of Pneumatic System • Availability • air is practically available every where in unlimited quantity • Transportation • can be easily transported in pipe lines • not necessary to return the compress air ms4.18 Basic Pneumatic System/Tieh SF
Advantages of Pneumatic System • Storage • compressor need not be in continuous operation • can be stored in and remove from a reservoir or cylinder • Temperature • insensitive to temperature fluctuation • ensure reliable operation ms4.18 Basic Pneumatic System/Tieh SF
Advantages of Pneumatic System • Explosion proof • no risk of explosion or fire • expensive protection against explosion is not required • Cleanliness • leaking air does not cause contamination • suitable for food, wood, textile and leather industries ms4.18 Basic Pneumatic System/Tieh SF
Advantages of Pneumatic System • Construction • simple construction • inexpensive • Speed • very fast working medium • cylinders have working speed of 1 ~ 2 m/s ms4.18 Basic Pneumatic System/Tieh SF
Disadvantages of Pneumatic System • Preparation • require to remove dirt and humidity • Compressible • Not possible to achieve uniform and constant piston speeds. ms4.18 Basic Pneumatic System/Tieh SF
Disadvantages of Pneumatic System • Force requirement • low working loads • the require output force is economical only up to about 20 KN to 30 KN • commonly used working pressure of 7 bar • Cost • Expensive to produce ms4.18 Basic Pneumatic System/Tieh SF
Disadvantages of Pneumatic System • Exhaust air • noisy • the oil mist with compressed air escapes with the exhaust to the atmosphere ms4.18 Basic Pneumatic System/Tieh SF
Silencer 2 1 3 Symbol to ISO 1219 ms4.18 Basic Pneumatic System/Tieh SF
Muffler Cutaway of a muffler Symbol to ISO 1219 ms4.18 Basic Pneumatic System/Tieh SF