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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.
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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
This means that liquids can be used to send forces from one place to another in hydraulic systems Liquids cannot be compressed because the particles are already close together
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.
f p a Hydraulic systems Force = 20N Force = 10N Y X Area = 10cm2 pressure= force Area = 40cm2 area
Examples • Car brakes • Dump truck lift • Hydraulic lifts: raise cars off the ground • Video
Whyis a leak in a hydraulicsystem a problem? Answer: In orderforpressuretobetransmitted in a fluid, the fluid mustbeconfined. Ifthehydraulicsystemisleaking, the fluid isnotconfined.
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 Examples: Bus ramps Bus doors Dentist drill Nail gun Lungs Scuba gear Video