The Basics of the Hydraulic System
At the most basic level, any hydraulic system can be explained as one force that is applied to one point, or piston, and is then transmitted to another point through the use of an incompressible, confined fluid. A hydraulic system confines the liquid in such a way that it uses the laws governing liquids to transmit power to do work. Visit Moog servo valve for more info. In the mid 17th century, Blaise Pascal formulated the basic law of hydraulics
Pascal discovered that pressure exerted on a fluid acts equally in all directions. Pascal's law states that pressure in a confined fluid is transmitted undiminished in every direction and acts with equal force on equal areas and at right angles to a container's walls.
Typically, the fluid used to transfer the motion is a type of oil. Because oil is incompressible it is very efficient for the transfer of motion and force. One important factor to take into account is that a hydraulic system cannot contain any air. If there were an air bubble in the system then the force applied to the first piston would be used to compress the air bubble, instead of going on to move the second piston. This goes on to affect the efficiency of the system.
A simple example of a basic piston-driven hydraulic system is the brakes of any standard car. When the brake pedal is depressed, it pushes on the piston in the master cylinder of the brake. Four other slave pistons in each wheel actuate to press the brake pads against the brake rotor to stop the car.
Generally, these systems involve equipment meant to handle heavier weights. This requires more physical strength as well as higher operating pressure for the system. Hydraulic system operating pressure ranges from a few hundred pounds per square inch (psi) to several thousand pounds per square inch.
Hydraulic systems offer advantages over other methods of power transmission. For example, hydraulic systems have a simple design. In many cases, complicated mechanical linkages can be replaced with a few preengineered hydraulic components. These systems are also more flexible. The location of component in a system is extremely versatile.
Instead of sedentary mechanical elements, flexible pipes and hoses used in these systems eliminate location problems. Additionally, these systems are also much more smooth and quiet while in operation.
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