HYDRAULIC AND PNUEMATIC ACTUATION SYSTEMS

WHAT WE MEAN BY THESE When we speak about hydraulics and pneumatics, simply put this means using a medium, be it air or a hydraulic fluid (usually oil) to flow under pressure around a circuit of pipework to provide drive or motion to a piece of mechanical equipment. To make things simplistic, both systems work in the same way, with virtually identical components used to achieve the same thing. The main difference being is the medium used to provide pressure or load in the system; hydraulic fluid is non compressible. We will look at each system and the components that make up the system. http://www.bbc.co.uk/schools/gcsebitesize/design/systemscontrol/pneumaticsrev 3.shtml

HYDRAULIC CIRCUIT SYSTEM COMPONENTS

HYDRAULIC CIRCUIT SYSTEM COMPONENTS Electric motor This is the part which provides drive and motion to the pump, which is the unit which drives the fluid medium (hydraulic oil) around the hydraulic circuit system. Oil Reservoir The oil is centrally held here at this single location & any oil that flows out of components is generally routed back to return here. Filter Any particulate contamination from the oil reservoir that could damage the more sensitive hydraulic components are screened out here

HYDRAULIC CIRCUIT SYSTEM COMPONENTS Pressure Regulator This is this part of the hydraulic system that reduces the input pressure of a liquid to a desired value at its output. Control Valve Within the hydraulic system, a control valve will control the direction of supplied air, so it can for example allow flow either only in or out. Cylinder This is the part that plays the most wanted action, in providing actuation in either a lifting or lowering movement.

PNUEMATIC CIRCUIT SYSTEM COMPONENTS

PNUEMATIC CIRCUIT SYSTEM COMPONENTS Aftercooler This is the part that appears directly after the compressor & is designed to cool the air after it has been pressurised. Compressor This pumps the air though the pneumatic system at a high pressure so it can be used to actuate certain parts with the pneumatic circuit. This driven by the electric motor. Filter This is the primary part of the pneumatic system & performs the task of removing any particles from entering the sensitive compressed air system. Pressure Regulator This is this part of the pneumatic system that reduces the input pressure of a gas to a desired value at its output.

PNUEMATIC CIRCUIT SYSTEM COMPONENTS Control Valve Within the pneumatic system, a control valve will control the direction of supplied air, so it can for example allow flow either only in or out. Cylinder This is the part that plays the most wanted action, in providing actuation in either a lifting or lowering movement. Air Receiver This is in effect a large storage vessel for the pressurised air in the system & can store air at high pressure for long periods of time. Safety Valve This is an essential part of the pneumatic system, providing a safe means of releasing air should the system become over pressurised.

HYDRAULIC AND PNUEMATIC SYSTEMS The main advantage with a hydraulic system is that the hydraulic oil can be compressed to such a high pressure that heavy loads can be powered. https://www.youtube.com/watch?v=Lv4bRPg7WEg The main advantage of using compressed air in a pneumatic system to provide drive to a cylinder is speed the action is achieved. https://www.youtube.com/watch?v=ll_3WLydmrw

Pneumatics System Safety Considerations Should the pneumatic system ever have maintenance performed on it, the system should be depressurised. The supply of the air needs to be isolated correctly so no part of the circuit can be become unwantedly pressurised. The same isolation procedure should also be applied to any electrical parts during maintenance.

Hydraulics System Safety Considerations Should the hydraulic system ever have maintenance performed on it, the system should be depressurised. The supply of the oil needs to be isolated correctly so no part of the circuit can be become unwantedly pressurised. The same isolation procedure should also be applied to any electrical parts during maintenance. Any oil leaks require immediate cleaning as these could pose a health hazard to the engineers maintaining the system and/or danger to the surrounding environment.

Pneumatics System Maintenance Checks The safety valve would require checking for correct functioning under pressure and that there is no physical damage to it. The air filter would require checking for its condition, possibly changing for a new one if it has been in the system for some time. The compressor would be checked for mechanical and electrical integrity. The pressure gauge would require checking for correct functioning under pressure and no physical damage is visible. The air receiver would require checking for its physical integrity, working at the correct pressures & any air leaks. The cylinder would require checking for correct directional operation. The entire system of pipework would require checking for air leaks & its physical condition.

Hydraulics System Maintenance Checks If fitted with a safety valve would require checking for correct functioning under pressure and that there is no physical damage to it. The oil filter would require checking or its condition, possibly changing for a new one if it has been in the system for some time. The pump would be checked for mechanical and electrical integrity. The pressure gauge would require checking for correct functioning under pressure and physical damage presence. The oil reservoir would require checking for its physical integrity, working at the correct pressures & any oil leaks. The cylinder would require checking for correct directional operation. The entire system of pipework would require checking for oil leaks & its physical condition.

References For merit consideration: https://www.quora.com/What-are-the-main-differences-between- hydraulic-and-pneumatic-Why-are-hydraulics-more-widely-used