13 February, 2014

Hydraulics

. After looking around, I learned — Hydraulics is a topic of science and engineering dealing with the mechanical properties of liquids. Hydraulics is part of the more general discipline of fluid power. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. Hydraulic topics range through most science and engineering disciplines, and cover concepts such as pipe flow, dam design, fluid control circuitry, pumps, turbines, hydropower, computational fluid dynamics, flow measurement, river channel behavior and erosion. The word "hydraulics" originates from the Greek word (hydraulikos) which in turn originates from meaning water organ which in turn comes from (water) and (pipe). Pneumatics (from the Greek pneumatikos, coming from the wind) is the use of pressurized gas to do work in science and technology. Pneumatics was first documented by Hero of Alexandria in 60 A. D. , though the subject had been known before then. Application Pneumatics is employed in a variety of settings. In dentistry applications, pneumatic drills are lighter, faster and simpler than an electric drill of the same power rating (because the prhyme mover, the compressor, is separate from the drill and pumped air is capable of rotating the drill bit at extremely high rpm). Pneumatic transfer systems are employed in many industries to move powders and pellets. Pneumatic tubes can carry objects over distances. Pneumatic devices are also used where electric motors cannot be used for safety reasons, such as deep in a mine where explosive dust or gases may be present. Examples of pneumatic tools: * Pneumatic drill (jackhammer) used by road workers * Pneumatic switches * Pneumatic actuators * Air compressors * Vacuum pumps * Barostat systems used in Neurogastroenterology and for researching electricity * Cable Jetting – a way to install cables in ducts * Pneumatic mail systems * Air brakes on buses, trains and trucks Comparison to Hydraulics Both pneumatics and hydraulics are applications of fluid power. Pneumatics uses air, which is compressible, while hydraulics uses relatively incompressible liquid media such as oil or water. Most industrial pneumatic applications use pressures of about 80 to 100 pounds per square inch (psi) (500 to 700 kilopascals). Hydraulics applications commonly use from 1,000 to 5,000 psi (7 to 35 MPa), but specialized applications may exceed 10,000 psi (70 MPa). Advantages of pneumatics * The working fluid is very light in weight so supply hoses are not heavy. * Because the working fluid is (mostly) just air, there is usually no need for a return line for the working fluid and leaks of the working fluid tend not to be messy. * Because air is compressable, the equipment is less likely to be damaged by shock. The air in pneumatics absorbs excessive force, whereas the fluid of hydraulics directly transfers force. Advantages of hydraulics * Higher energy density owing to the much higher working pressures usually employed. * The hydraulic working fluid is basically incompressible, leading to a minimum of spring action. When hydraulic fluid flow is stopped, the slightest motion of the load releases the pressure on the load; there is no need to "bleed off" pressurised air to release the pressure on the load.

A video by Jim Pytel for renewable energy technology students at Columbia Gorge Community College.


About The Author

admin

4 Comments

  1. Dee RR February 12, 2014 at 9:12 am #
    Hydraulics are the things that make the cars go up and down or drive while on two wheels
  2. Terry February 12, 2014 at 9:13 am #
    Hydraulics use fluid pressure in cylinders to move pistons and do work. Pneumatics use air.
  3. Randi Hall February 12, 2014 at 3:15 pm #
    Hydraulics is the science of conveyance of liquids through pipes as motive power. Both water and oil can be used. Normally used to lift, move, control and operate devices. Pneumatics. The science of the mechanical properties of gases. Normally air is used to lift, operate,move or control devices. Both are used extensively in industry, process control . Hydraulics machinery is more powerful.
  4. Randi February 12, 2014 at 7:32 pm #
    To be a bit more correct, hydraulics use fluids (often some sort of oil) to exert pressure and do work. Pneumatics use gases (air or any other compressed gas).