Jan 10th

Question 1

Name some of the basic principles of hydraulics.

Answer 1

Liquids Have no shape of their own
Liquids are Practically incompressible
Liquids transmit applied pressure in all directions
Liquid provides great increase in work force.

Question 2

How is pressure created in hydraulics.

Answer 2

Pressure can only be created by resistance to flow

Question 3

What happens during flow across and orifice ?

Answer 3

Results in a pressure drop that is directly proportionate to the area of the orifice opening.

Question 4

When _____ is put into a hydraulic system in the form of flow under pressure it will result in either flow or heat.

Answer 4

Energy

Question 5

What are the main advantages of hydraulics ?

Answer 5

Flexibility 
Simplicity 
Compactness 
Economic 
Safety 
Efficiency 
Cleanliness

Question 6

What is the PTO

Answer 6

Power take off
Is any of several methods for taking power from a power source (engine) and transmitting it to the hydraulic pump.
NOT A PART OF THE HYDRAULIC SYSTEM

Question 7

Describe a hydraulic pump

Answer 7

Concerts mechanical force into Hydraulic energy (fluid power)
Does not create pressure just flow

Question 8

What kind of displacement pump would you find on an open centre system and define it

Answer 8

Fixed displacement pump
These move the same volume of oil with every cycle
The volume is only changed when the speed of the pump is changed.

Question 9

What kind of displacement pump would you find on a closed centre system and define it

Answer 9

Variable displacement pump
Can vary the volume of oil they move with each cycle even at same speed.
Internal mechanism varies the displacement and output
Used where pressure and flow must be maintained

Question 10

Define a hydraulic motor

Answer 10

Works in reverse of a pump converting fluid energy back to mechanical
Ex winch, swing

Question 11

Define hydraulic cylinder

Answer 11

Does the work of the hydraulic circuit.

Question 12

What does the hydraulic reservoir do ?

Answer 12

Not only stores oil but also helps keep the oil clean, free of air and cool.

Question 13

What do the hydraulic control valves do.

Answer 13

Direct the flow of oil in hydraulic systems

Question 14

What is a hydraulic check valve

Answer 14

A simple one way valve that can be a separate component but usually is a part of another complex valve

Question 15

What is a hydraulic holding valve designed for ?

Answer 15

Double acting cylinders which are supposed to hold pressure.

Ensures smooth decompression prior to return of the cylinder

Question 16

What is the purpose of a hydraulic relief valve

Answer 16

High pressures can damage hydraulic components, relief valves remedy this situation when oil pressure gets too high they relive the flow by diverting oil into an auxiliary direction

Question 17

What is the role of an accumulator

Answer 17

There to maintain a specific pressure in a closed centre hydraulic system. This allows for a smooth engagement of components when the pump is not providing full pressure due to start delay

Question 18

What device measures the amount of pressure at any given section.

Answer 18

Hydraulic gauge

Question 19

What does a hydraulic filter do

Answer 19

Removes contaminants from the system

Question 20

What is the job of a hydraulic cooler

Answer 20

To remove access heat generated by energy losses in a system as well as that from external sources

Question 21

How does a hydraulic swing motor work

Answer 21

Oil flows through the motor which turns the pinion gear, the pinion gear interacts with a gear on the turntable allowing the upper structure to swing/slew

Question 22

How does a hydraulic boom cylinder work

Answer 22

As oil flows through the cylinder it pushes the rod out to raise the boom , reverse the flow and the boom lowers

Question 23

What is the difference between single and double acting cylinders

Answer 23

Single uses hydraulic pressure to extend then retracts under gravity
Double acting cylinder uses hydraulic pressure to extend and retract.