Fluid Power Systems Chapter 9
What are fluid power systems? • Hydraulic systems are systems that control and transmit energy through liquids • Pneumatics systems use gases instead of using liquids
Why use fluid power? • Fluids cant break like machine parts • Longer life expectancy • Unlimited amount of power can be created and maintained • Has easy and complete control over a wide range of power. • Has natural springiness which provides a better cushion that reduces shock
The physics of fluid power systems • Fluids exert pressure • Pressure is the force that is acting upon a certain area • Water tends to balance itself with pressure • Compressibility is how much of any matter can be squashed into a smaller space
Blaise Pascal • Was a scientist that studied the properties of confined liquids. • Found out that liquids are compressed on both sides of a container • And he used the property into making hydraulics capable of increasing mechanical advantage
Comparison of Liquids and gases • Molecules in liquids are closer than the ones in gases. • Compressibility is easier to accomplish in gases than it is in liquids • Liquids must have a closed system to hold the water and pneumatic systems can be open.
Hydraulic pumps • Hydraulic pumps are used to supply and transmit the pressure needed to use a hydraulic power system
Gear Pumps • Are used to create the pressure needed to use many hydraulic systems
Centrifugal Pumps • Also used to produce pressure in hydraulic systems. • Uses centrifugal force to move fluids in a system • Uses a device called the impeller. • Impeller consist of many small blades mounted on a shaft.
Reciprocating Pumps • Also called positive displacement pumps • Uses a piston to move hydraulic fluid
Air Compressors • Convert mechanical energy that is input into a pneumatic power system.
Valves • Valves are the devices that control fluid power • Used for flow control, pressure control, and directional control. • Valves that are used in hydraulic systems are to seal and prevent loss of water.
Flow Control Valves • Are used when you want to start or stop the flow of liquid in a system • Example: kitchen sink
Pressure Control Valves • Also known as relief valves. • They are in a system to make sure that the pressure doesn’t get too high
Directional Control Valves • Controls what path the fluid takes in a circuit • Can be operated manually, mechanically, or electrically.
Actuators • Are devices that convert fluid power into mechanical power in hydraulic and pneumatic systems • This helps to make fluid power systems easy to design and use. • Make the reciprocating and rotary motion • Ex: cylinder
Fluid Motors • Devices that convert fluid power into rotary mechanical motion • Two types- gear motor and vane motor • Gear motor works like a gear pump except the process is reversed.
Torque Converters • Devices that use fluid pressure to connect and disconnect moving parts