Week 24 - Hydraulic Systems and the Development of Mechanical Devices

Lesson 12

Lesson 12: Hydraulic and Pneumatic Devices

Our lives would be very different without the use of hydraulic and pneumatic equipment. You will recall from the last few lessons that hydraulic machines use liquids push pistons. Pneumatic machines use air. Hydraulic systems use liquids because they are non-compressible. That means the volume of liquid does not get smaller under pressure. Air, and other gases,do compress so their not very useful in the type of piston machines we have looked at in the last few lessons.

Most pneumatic machines take advantage of the fact that air is compressible. Many construction workers now use pneumatic nailers because they are much faster than using hammer and nails.

Another common tool seen during the summer is the jack hammer. It uses compressed air to breakup cement or open up pavement for repairs. Many other pneumatic tools are used in auto repair such as sheet metal cutters and sanders.

When we want to move a lot of dirt around we bring in the big machines.

Exercise 4.3: Equipment Survey

	Hydraulic machines can be a life-saver in emergency situations. Commonly known as the jaws of life these machines can open a vehicle that has been damaged in an accident and rescue the trapped and injured person inside.
Hydraulic machines can be used to create excitement and fun as well. Think of all the rides you've been on at the circus and how they used hydraulics.