Postive Displacment Pumps

Question 1

What are the 2 types of positive displacement pumps?

Answer 1

Rotary and reciprocating

Question 2

Reciprocating and rotary pumps can either be what 2 types?

Answer 2

Fixed or variable displacement

Question 3

Diaphram and piston pumps are considered what type of pump?

Answer 3

Reciprocating

Question 4

Gear and vane pumps are considered what type of pump?

Answer 4

Rotary

Question 5

What are the 3 components inside of vane pumps?

Answer 5

Ring, vane and rotor

Question 6

What are the 2 types of positive displacement pump mounts?

Answer 6

Frame mounted and C frame mounted

Question 7

Disadvantage of a frame mounted pump?

Answer 7

Motor and pump must be aligned

Question 8

A fixed displacement pump must have what to limit system pressure?

Answer 8

Relief valve

Question 9

A variable displacement pump uses a relief valve to back up what?

Answer 9

Pressure compensator

Question 10

What does the compensator do?

Answer 10

Controls system pressure

Question 11

How do you control pressure in a fixed displacement pump?

Answer 11

Divert off excess flow

Question 12

How do you control pressure In a variable displacement pump?

Answer 12

Stop flow at the pump

Question 13

Purpose of a relief valve?

Answer 13

Limits system pressure

Question 14

3 things that cause true pump cavitation?

Answer 14

Cold oil, restriction on the Inlet and suction lift rating

Question 15

What causes pseudo cavitation?

Answer 15

Air leak on the Inlet side and not maintaining oil levels

Question 16

How to tell you’re dealing with pseudo cavitation?

Answer 16

Foamy hydraulic fluid in the tank

Question 17

Definition on cavitation?

Answer 17

Formation and collapse of Air bubbles in the pump