Fluid power

From Free net encyclopedia

Fluid power is the technology that deals with the generation, control, and transmission of pressurized fluids.

As the term fluid refers either to gases or to liquids, fluid power is also subdivided into the categories of hydraulics and pneumatics. The differences being that with hydraulics the medium used is a liquid (ie mineral oil or water) and for pneumatics it is a gas (ie air or another inert gas).

1 Practical use
2 Application
3 Reference
4 See also
5 External links

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Practical use

In practice fluid power is used to achieve one of two generic tasks:

Transport fluid
Delivering the fluid from one location to another to achieve a useful purpose.
An example of this in the case of hydraulics is a lube oil system to provide oil to lubricate bearings on heavy equipment.

Transport energy
In this case the fluid flow is used to actuate a device specifically designed to operate from the flow provided. In general these devices can be described as either a cylinder (providing a linear output force/motion) or motor (providing a rotary output).

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Application

While hydraulics and pneumatics are similar in many respects there are distinctive reasons for using one over the other.

Due to the explosive nature of gases under high pressure pneumatics in general are used only into the range of 100psi(7bar) due to the hazard of a line breach. As such when higher force or torque is required a hydraulic system is generally used rather than usuing a much larger motor or cylinder.

In terms of controllablity gases, unlike liquids, change volume significantly when pressurized making it difficult to achieve a precise position if required. With this in mind then hydraulics would typically once again be used in place of pneumatics.

However, pneumatic systems are considerably less expensive to build and operate. This is due in part by the fact that in general air is used as the medium and as such no resevoir is required to store the medium nor is there a need to provide a means to recover the medium.

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