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Flashcards in Pump Fundementals Deck (27)
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1

A hydraulic pump converts what forms of energy

Mechanical to Hydraulic

2

What is basic pumping principle

As internal volume increases a low pressure area is created, vice versus on high side

3

What happens if a pump is oversped

Cavitation, the inlet does not have time to fill before the pocket is closed off

4

Volumetric effieciency

Expresses how effectively a hydraulic pump generates flow. calculated by comparing theoretical flow rate and actual flow

5

Advantages of external gear pump

Cheap
More tolerant of contamination
Least complex

6

Unbalanced pumps

When the inlet and the outlet are opposite each other causing the high pressure to push the internal components toward the inlet

7

Uni-directional pump

The pump can only be rotated in one direction

8

On a bi-directional pump what happens if the high pressure check valve leaks

Pump flow will go down as oil is returning to the inlet

9

Intra vane

High pressure oil is pumped into the intra vane pocket at all times
Underside of vane has pocket pressure behind it

10

Vane cam ring

Round will be a un-balanced design
Elliptical will be a balanced design
Vertical holes in ring are connected to the inlet to ensure pump receives sufficient oil

11

To change the direction of a vane pump the cam ring will appear to have rotated ______ degrees

90

12

Vane pump compensator

Compensator spring pushes cam ring to max flow, as outlet pressure increases it pushes the cam ring back towards the compensator spring, deceasing the change in pocket size

13

Vane pump vane tips

Angled are uni-directional
Round, double angle and square are bi-directional

14

The wear in a unbalanced vane pump will show where

The shaft bushings

15

Where should case drain be located on a axial piston pump?

Between 10 and 2
Housing will be over half full to maintain lube (bath lube)

16

The drive shaft of a bent axis piston pump is supported by?

Double taper roller bearing

17

A pump termed reversible is able to

Reverse the direction of oil flow through the pump

18

What are pressure plates used to do in a vane pump

Control the rotor side clearance

19

What is utilized to keep vanes forced against the cam ring

Centrifugal force
High side pressure inside intra vane pocket
pocket pressure acting on backside of vane

20

Radial cam piston pump

Pistons have a dual check system one allows oil to be drawn in from inlet manifold on down stroke, on up stroke intake ball closes and the outlet ball opens and oil goes out to high pressure manifold

21

Variable displacement radial cam piston pump

High pressure oil is pumped into housing and holds pistons up reducing the effective stroke of the piston

22

The 2 factor that determine the amount of internal leakage in a pump are?

Pressure difference between inlet and outlet
Amount of internal clearance

23

What 2 forces act on the vanes of a typical vane pump

Outlet pressure oil
Centrifugal

24

Pressure plates in vane pumps are used to control what

Rotor side clearance

25

Comparing input power to output power of a pump is what eff.

Overall

26

As a pumps outlet pressure increases what happens to leakage

Increase

27

A hydraulic control system that copies the movement of the control lever is called a

Servo system