Fluid Power Final

Question 1

Most common type of non positive displacement pump?

Answer 1

Centrifugal

Question 2

2 types of positive displacement pumps?

Answer 2

Fixed and variable displacement

Question 3

Types of fixed displacement pumps

Answer 3

Gear pumps, vane pumps, piston pumps, diaphragm pumps

Question 4

Types of variable displacement pumps?

Answer 4

Piston pump and vane pump

Question 5

Without a change in volume in a pump….

Answer 5

No fluid will flow through

Question 6

Definition of a pumps capacity?

Answer 6

The amount of fluid a pump can move in a given time

Question 7

What is a pumps flow measured in?

Answer 7

GPM (gallons per minute)

Question 8

What 3 things determine a pumps capacity?

Answer 8

1. Size of pumping element
2. Viscosity of fluid
3. Rpm

Question 9

What are 2 ways pressure can be controlled?

Answer 9

1. At the pump (pressure compensator)
2. Deviate off unneeded flow (relief valve)

Question 10

How to know which side is the Inlet and outlet of the pump?

Answer 10

Inlet is the bigger size and the outlet is the smaller size

Question 11

Definition of pump cavitation?

Answer 11

The formation and collapse of air bubbles

Question 12

What are some things that would make a pump cavitate?

Answer 12

Blockage on the Inlet or the viscosity of fluid in the pump

Question 13

What is the other type of pump cavitation?

Answer 13

Pseudo cavitation

Question 14

If pseudo cavitation is taking place, how may the system be running?

Answer 14

Spongey

Question 15

Reasons for pseudo cavitation?

Answer 15

Leak on the Inlet side of the pump, excess air in the system, tank level too low

Question 16

What would be a good indicator of pseudo cavitation?

Answer 16

The fluid in the tank would be foamy

Question 17

4 ways valves are actuated?

Answer 17

1. Manually
2. Mechanically
3. Electrically
4. Pilot pressure

Question 18

4 center conditions for DCV’s?

Answer 18

1. Blocked
2. Tandem
3. Float
4. Open

Question 19

3 uses for an accumulator?

Answer 19

1. Absorb shock
2. Maintain pressure
3. Establish flow

Question 20

What does cracking pressure mean?

Answer 20

When a valve opens prematurely

Question 21

What does a sequence valve do?

Answer 21

Allows one thing to happen before the other. To have reverse flow you must have a bypass check valve.

Question 22

What does a pressure reducing value do?

Answer 22

Normally passing, once downstream flow reaches the valve pressure, the valve become non passing and fluid stops flowing

Question 23

What does a counter balance valve do?

Answer 23

Counter acts a weight on a cylinder

Question 24

What is the job of a relief valve and how do you trouble shoot it?

Answer 24

To limit system pressure and to make sure it starts flowing at the set point

Question 25

What percentage of hydraulic fluid is air?

Answer 25

10% air by volume