PSAA Curriculum

1
PSAA Curriculum

• Unit
• Physical Science Systems

2
Problem Area

• Energy and Power Systems

3
Hydraulic Power Transmission

• Lesson

4
What are some specific applications for
hydraulics?

• Make a list of equipment and the specific
  applications of hydraulics.
• Why are hydraulics a part of so many pieces of
  agricultural and industrial equipment?

5
Learning Objectives

• Identify the components of a hydraulic system and
  explain its operation.
• Determine the efficiency of a hydraulic power
  system.
• Calculate the actual and ideal mechanical
  advantages of a hydraulic system.
• Explain the common uses of hydraulic systems on
  agricultural machines.

6
Terms

• Pascals Law
• Pressure
• Pump
• Reservoir
• Syringe
• Work

• Actual mechanical advantage
• Area
• Circuit
• Efficiency
• Force
• Hydraulics
• Ideal Mechanical Advantage

7
What are the basic components of a hydraulic
system and the role each component plays in the
system?

• Hydraulics is the science of liquid in motion.
• Air is compressible but liquids cannot be
  compressed.
• A system that uses oil or another type of liquid
  is known as a hydraulic system.

8
What are the basic components of a hydraulic
system and the role each component plays in the
system?

• A basic idea behind any hydraulic system is that
  when a force is applied at one point, the force
  is transmitted to another point using an
  incompressible fluid.
• The fluid is usually an oil and the force usually
  multiplied during the process.

9
Basic to any hydraulic system are

• A pump, which creates pressure for the system.
• A rotor or cylinder, which transfers the
  hydraulic energy back into mechanical energy in
  the form of rotary or linear motion.
• The cylinder in this lesson consists of a
  disposable syringe to transmit the energy.

10
Basic to any hydraulic system are

• Lines, which transfer the hydraulic energy from
  the pump to the rotor or cylinder and return the
  energy to the pump.
• A reservoir to store a supply of fluid.
• Valves to control, or direct, the fluid and its
  movement.
• All the components make up the hydraulic circuit
  that completes the loop.

11
Hydraulic Power Transmission Laboratory Setup
Diagram
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Hydraulics (cont.)

• Pressure may be defined as the potential energy
  of a fluid power system.
• Applying pressure to some unit area develops
  force.
• Pressure is calculated by dividing the force by
  the area.
• Applying a pressure of ten pounds to one square
  inch area of a plunger in a hydraulic cylinder
  will exert a pressure of ten pounds on each
  square inch of the system.

13
Hydraulics (cont.)

• Pascals Law states that pressure exerted at any
  point on a confined static liquid is transmitted
  with equal force on equal areas at right angles
  to all surfaces.

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Hydraulics (cont.)

• The scientific definition for work involves using
  a force to move an object.
• In hydraulics force and work are inversely
  proportional, meaning one must be sacrificed for
  the other in the system.

16
Hydraulics (cont.)

• In a hydraulic system involving two pistons, when
  one piston is six times larger than the other
  piston, a force applied to the smaller piston
  will appear six times greater on the larger
  piston, but the smaller piston will have to
  travel six times farther in travel distance.

17
How is the efficiency for a hydraulic system
calculated? What factors affect the efficiency of
the system?

• The efficiency of a system is usually calculated
  by comparing the output to the input of the
  system.
• In a hydraulic system, efficiency is determined
  by dividing the actual mechanical advantage by
  the ideal mechanical advantage and multiplying
  the result by 100 to obtain a percentage of
  efficiency.

18
Efficiency of the hydraulic system

• Efficiency of the hydraulic system in the
  experiment can be affected by various factors,
  the most obvious being friction.

19
Efficiency of the hydraulic system

• If the weights providing the force are not
  properly placed and the force does not push
  directly straight down on the hydraulic piston,
  additional force can be exerted horizontally
  between the plunger and cylinder wall.
• This outward force will increase the effort
  needed to lift the resistance and reduce the
  efficiency, because the actual mechanical
  advantage will be decreased.

20
How is actual mechanical advantage and ideal
mechanical advantage calculated for a hydraulic
system?

• Ideal mechanical advantage is the theoretical
  advantage that the system would have if there
  were no outside influences or limitations such as
  friction of the fluid or the plungers against the
  walls of the syringe or hydraulic piston.
• Ideal advantage assumes that there is no air
  present in the system and there are no fluid
  leaks as well.

21
Ideal Mechanical Advantage

• Ideal mechanical advantage in a hydraulic system
  is determined by dividing the area of the larger
  piston by the area of the smaller piston.
• Area of the piston is calculated by squaring the
  diameter of the piston, multiplying by pi (3.14)
  and dividing by 4.
• Area is reported in square units such as square
  inches or square centimeters.

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Actual mechanical advantage

• Actual mechanical advantage is the actual
  advantage gained when all these limitations and
  factors are considered by comparing the loads
  placed on the system.
• Actual mechanical advantage is determined by
  dividing the resistance force by the effort
  force.
• The resistance force is the object(s) attempting
  to be moved by the hydraulic system.

24
What uses exist in the agriculture industry for
hydraulics?

• Examples of hydraulics exist everywhere in the
  world, and agriculture is no exception when it
  comes to uses of hydraulics.
• From log splitters in your backyard to gigantic
  machines we see on construction sites, hydraulic
  equipment is amazing in strength and agility.

25
What uses exist in the agriculture industry for
hydraulics?

• In construction zones, we see hydraulically
  operated equipment in the form of bulldozers,
  shovels, cranes, and forklifts.

• Another common piece of equipment at construction
  sites and agricultural facilities is the
  skid/loader using hydraulics to rotate the
  bucket, lift the bucket, and to raise and lower
  the bucket.

26
What uses exist in the agriculture industry for
hydraulics?

• Large dump trucks usually have one cylinder or
  two to lift the bed.
• These cylinders telescope, which gives them a
  large range of motion for dumping loads, such as
  rock or grain.

• Even the brakes in our automobiles use hydraulics.

27
Review/Summary

• What are the basic components of a hydraulic
  system and the role each component plays in the
  system?
• How is the efficiency for a hydraulic system
  calculated?
• What factors affect the efficiency of the system?

28
Review/Summary

• How is actual mechanical advantage and ideal
  mechanical advantage calculated for a hydraulic
  system?
• What uses exist in the agriculture industry for
  hydraulics?