Chapter 9 :Hydraulics and Pneumatics
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Transcript of Chapter 9 :Hydraulics and Pneumatics
Chapter 9 :Hydraulics and Pneumatics
What we will learn this chapter
Hydraulic systems are systems that use a liquid under pressure to transmit a force and do work.
Liquids cannot be compressed because
the particles are already close together
Liquids cannot be compressed because
the particles are already close
together
This means that liquids can be used to send
forces from one place to another in hydraulic
systems
Liquids and Compression
Liquids CANNOT be compressed by ordinary means.
When pressure is applied to liquid in a pipe , the force can be transmitted over a distance.
Example: A long hose is connected to a water tap from the side of a building. Pressure is transmitted along the hose and forces the water out the other end of the hose.
Using Pascal´s Principle
Hydraulic devices
Hydraulic systems
Use liquids to transmit pressure in a confined fluid
A hydraulic system multiplies force by applying the force to a small surface area. The increase in pressure is then transmitted to another part of the confined fluid, which pushes on a larger surface area
Basic Hydraulic System 1) a pump, which creates
pressure for the system, and
2) a rotor or cylinder, which transfers the hydraulic energy back into mechanical energy in the form of rotary or linear
motion.
Hydraulic systems
Force = 10N
X Y
Area = 10cm2
Force = 20N
Area = 40cm2
pressure = area
force
Examples
Car brakes Dump truck lift Hydraulic lifts: raise cars off the ground Video
Why is a leak in a hydraulic system a problem?
Answer: Answer: In order for pressure to be transmitted in a fluid, the fluid must be confined. If the hydraulic system is If the hydraulic system is leaking, the fluid is not confinedleaking, the fluid is not confined.
Hydraulic brakes The brake system multiplies the force,
so a person can stop a large car with only a light push on the brake pedal
Pneumatic Systems
Pneumatic system: a system that uses a gas, usually air, under pressure to transmit a
force.
In order for a gas to be put to work in a fluid system, it must be compressed
ExamplesExamples:
Bus ramps
Bus doors
Dentist drill
Nail gun
Lungs
Scuba gear
Video