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papu55.ankan
09-22-2010, 08:13 AM
pls help to me to get some knowled n building of pneumatics......

Ulhas
09-22-2010, 08:34 PM
You must be very specific while asking
No one will teach you Pneumatic , there will be thousands pages if one really want to write a book on it and eventhough it will hardly cover entire pneumatic

So do little bit Google and what exactly you need.

docel
09-23-2010, 08:23 AM
1. It is pretty expensive.
2. Needs a lot of knowledge regarding pressure and motion dynamics.
3. Compressed air is quite a bit of force and involves a compressor, Regulator and flow-control Valves to control the compressed air to a piston- cylinder that moves linearly with the pressure exerted by the compressed air.
4. The entire system is pretty heavy too. Involves an electric motor driven Air compressor, Pressurised air tank, Air pressure gauges, Control valves, Reservoir/ buffer tank, Piston-cylinder actuator, special hose pipes, hose adapters, safety valves......
A simple system weighs about 10kgs. ( excluding the Compressor, ofcourse )

Ulhas
09-23-2010, 11:40 AM
Additionaly,
No system on earth exists having 100% efficiency.
As said if you need pneumatic power of X+losses You will need X+losses power at shaft of motor , motor will again not 80 % efficient, hence you need ~1.2* (X+losses) , in pneumatic power requirement is moderate as being a complex mechanical design, componets sizes are less variant compare to electrical or other and importantly it adds additional weight in your design.

So avoid energy conversion as far as possible, that means directly see the feasibility of using Electrical power for your work

docel
09-23-2010, 08:38 PM
Talking about efficiency...
80% efficiency motors are NOT used by hobbyists at all. They simply cant afford the cost. Why hobbyists- most industrial products dont use them too.

One cannot compare Pneumatics with electric, except for argument sake. Each have their advantages and disadvantages , for sure.
Electrics are expensive , when called for to do the same job of a Pneumatic system. The advantage is that electric is much lighter. What a 7bar pneumatic can do will become very complex ( and expensive) for an equivalent electric system. As far as a small job is concerned, the Electric has greater advantage.