Pressurized Fluid Systems: Hydraulics Describe the science underlying hydraulic technologies

Transcription

1 Pressurized Fluid Systems: Hydraulics Describe the science underlying hydraulic technologies

2 Hydraulics is the word we give to confined, pressurized systems that use moving liquids. These systems use liquids under pressure to move things. Backhoes and excavators use hydraulics to move soil.

3 Who is Blaise Pascal? June 19, 1623 August 19, 1662 Mathematician In a body of equally dense fluids at rest, the pressure is the same for all points in the fluid so long as those points are at the same depth below the fluid's surface.

4 Pascal discovered that pressure applied to a liquid in a closed container is transmitted equally in all directions, to all parts of the system. Because liquids are virtually incompressible, a force can be applied to a confined liquid. Hydraulic systems work because of the movement of a liquid or the force of a liquid in a closed system

5 A simple closed hydraulic system consists of two pistons or cylinder units filled with liquid and connected by tubing. When effort is applied to one piston, fluid moves through the system to lift the load on the second piston.

6 Pascal applied his law to the design of the Hydraulic press, which has many applications: Hydraulic brakes; hoists in service stations; loading docks at stores and factories; hydraulic ramps for people with disabilities; hydraulic blades on snow ploughs; the compactor in the back of a garbage truck; bulldozer blades and backhoe shovels

7 What makes up a Hydraulic System? The liquid put in a hydraulic system is called the hydraulic fluid. The fluid is sent along a conductor to a pump where it is pushed into a cylinder. A cylinder is like a syringe. The fluid pushes on the piston in the cylinder. This movement of the piston can be used to do work by moving something else.

8 What is a cylinder? A cylinder is the round, straight-sided cavity in which the pistons move up and down.

9 What is a piston? A mostly hollow cylindrical part closed at one end, fitted to each of the engine's cylinders and attached to the crankshaft by a connecting rod. Each piston moves up and down in its cylinder, transmitting power created by the exploding fuel to the crankshaft via a connecting rod ( plug).

10 A valve between the pump and cylinder controls the flow of fluid. This allows the piston to be moved a little or a lot. There is also a valve between the cylinder and storage tank, so that the fluid used is not wasted, but can be used again and again.

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12 Pumps and Valves Pumps are used to create flow of fluids. They can make fluids flow against gravity. Valves control the flow of fluid.

13 The Heart: A closed system

14 Blood is pumped from the heart; arteries deliver the blood to the tissues; and veins return the blood to the heart.

15 The heart has two central pumps: the right side and the left side. The pumping action depends on the contraction and relaxation of two muscles known as ventricles. Blood passes into the lungs, where the exchange of carbon dioxide for oxygen takes place.

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17 The arteries deliver blood at high pressure to all parts of the body. Just as valves are used to control the flow of fluid in hydraulic systems, so the flow of blood in the heart is controlled by valves that allow blood flow in only one direction.

18 If a valve becomes clogged hospitals now have the technology to replace them with an artificial one. The heart has a natural pacing system to control its rate and rhythm.

19 Artificial pacemakers restore proper heart rate when the natural system fails.

20 Understanding Concepts

21 List two industries that use hydraulic power. The Automotive Industry Construction Industry

22 What makes the fluid flow in a pressurized system? And what controls the flow? What makes the fluid flow in a pressurized system it the pump. It creates the flow of the fluid. The valves control the flow.