Sunday, July 13, 2008

Basic Hydraulic

A link showing the preview of a book on Hydraulics!

Just read and learn:

Hydrodynamics versus Hydrostatics

Two ways of trasmitting fluid energy
1. Hydrodynamic: the kinetic or the impact of the moving fluid is converted to
mechanical energy.
2. Hydrostatic: energy is transferred through a confined fluid by the pressure that is
created by the application of a force to that confined fluid.

Pascal’s Law
Pressure exerted on a confined liquid at rest is transmitted equally in all directions, is the
same at any point in the liquid, and acts at right angles to the surfaces of the container
1. Pascal’s law is valid irrespective of the shape of the vessel
2. Any change in the exerted pressure is seen almost instantly throughout the liquid.
3. Fluid in a system can be as rigid as steel for the transmission of power.

Advantages of Hydraulic Power Systems
1. Provide high levels of readily regulated torque and force
2. Offer infinitely variable linear or rotary speed over a wide range
3. Instantly reversible
4. Can be stalled without damage
5. High power output is possible
6. High accuracy and extreme stiffness
7. Possible to be automated without electronics
8. Fully adaptable to electrical or electronic controls
9. Provide cushioning to reduce the effects of impact or shoch loads
10. The fluid itself provides lubrication

Disadvantages of Hydraulic Power Systems
1. Hazards exist due to high-pressure
2. Fluids are flammable
3. Leakage is possible
4. Adequate filtration is necessary
Hydraulics are ideal for applications requiring high forces for heavy loads, long stroke
linear motion, rigidity and accuracy with heavy loads, high-stall torque, etc.

Press–Force–Area Relationship
Pressure is defined as
Pressure = Force/Area
p = F/A
Several conversion factors for pressure
• 1 psi = 6895 Pa = 6.895 kPa
• 1 bar = 14.5 psi = 100 kPa


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