What are the Pros and cons of hydraulic system?

Answer 1

Generally hydraulic systems are closed circuit, meaning that the liquid used (generally oil) is filtered and stored in a reservoir. pneumatic systems are often open, as air from the atmosphere is compressed in a tank before it is used, then released into the atmosphere afterward. the air tank is either charged before operation of the system, or continuously replenished by a compressor, (the compressor is run by a prime mover). the primary disadvantage of pneumatics, is that gas can be compressed, and decompressed, this is an advantage for storage, but makes control difficult. hydraulic systems do not have this problem, but the liquid in the system must be recirculated, thus requiring more maintenance, and also storage, as liquids do not compress. this is beneficial to control, because the liquid in a hydraulic actuator cannot be compressed, this provides rigidity when the liquid is not flowing, and precision when it is. another benefit of this rigidity is that good leverage is not needed in hydraulic systems many pieces of heavy machinery use third class levers with hydraulics because the mechanical advantage of a large hydraulic piston combats the poor leverage, a telescopic handler, wheel loader, and telescoping crane excellent examples of this. (include pictures of green forklift with log, grove crane and wheel loader on this slide)