Hydraulics Alberta Modules

Question 1

1psi = _ kpa

Answer 1

6.9 kpa

Question 2

1 psi = _ bar

Answer 2

0.069. Bar

Question 3

1 bar = _ psi

Answer 3

14.5 psi

Question 4

1 bar = _ kpa

Answer 4

100 kpa

Question 5

1 atmosphere = _ psi

Answer 5

14.7 psi

Question 6

1 atmosphere = _ kpa

Answer 6

101.325 kpa

Question 7

Gauge pressure read what when system has atmosphere pressure

Answer 7

0

Question 8

Absolute pressure reads what with atmosphere pressure

Answer 8

14.7

Question 9

Small piston force pressure vs big piston force pressure

Answer 9

Big piston has more pressure because bigger area

Question 10

Force =

Answer 10

Diameter square ×0.7854 × pressure

Question 11

If a piston has a rod and you want to know the force what do you do

Answer 11

Take cylinder force minus rod force
Force = diameter squared × 0.7854 × pressure

Question 12

Flow is produced by

Answer 12

Either a pump or by a pressure drop across an orifice.

Question 13

Pressure is produced by

Answer 13

Resistance to flow

Question 14

There is only flow across an orifice if

Answer 14

There is a pressure drop

Question 15

Flow is expressed as

Answer 15

Velocity in speed ft/min or ft/sec
Or flow rate in gallons/min
Or cubic inches/min

Question 16

Flow triangle is

Answer 16

Answer 17

Multiple gallons by 231

Question 18

Recommend max inlet velocity =
Recommend pressure line velocity =

Answer 18

2 to 4 ft/sec

7 to 20 ft/sec

Question 20

Cavitation effects 7x

Answer 20

*Vary rapid erosion of metal surfaces.
* severe pump damage
*generation of high frequency vibration
*erratic operation of valves and actuators
*accelerated fluid oxidation
*interference with lubrication of components.

Question 21

Causes of cavitation 7x

Answer 21

• clogged inlet filter
• pump mounted to high above resivor
  *fluid is to thick viscosity to high
• clogged breathers
  *too many bends or fittings
  *inlet pipe is too small
  *turbulence

Question 22

Work =

Answer 22

Force ×distance

Question 23

Power=

Answer 23

Force ×distance ÷time

Question 24

1 HP = _ FT pounds /min

Answer 24

33 000 ftlbs/min

Question 25

Define cavitation

Answer 25

Cavitation is the violent collapse of entrainted gas bubbles.

Question 26

What causes aeration

Answer 26

Occurs when air gets into the fluid from an outside source.

Question 27

Volumetric efficiency =

Answer 27

Percent out volume/input volume

Question 28

Pressure tubing limited to what size Generally

Answer 28

2 inches larger is ultra tp 12 inches

Question 29

Tube is available in

Answer 29

Steel,copper, aluminum, plastic

Question 30

3 types of copper tube

Answer 30

Plumbing Oxygen Air conditioning and refrigeration (acr) Not used for hydraulic system.

Question 31

Plumbing tube designation

Answer 31

K (thick wall) L (med wall) M (thin wall)

Question 32

Oxygen tube designation

Answer 32

K or L tube that has been specially cleaned to avoid spontaneous combustion of hydrocarbons with oxygen

Question 33

Acr tube sized by

Answer 33

Outside diameter it was been cleaned purged and capped

Question 34

Specify following when selecting tubing

Answer 34

Material OD wall thickness Working pressure Working temperature

Question 35

Tube measurements

Answer 35

Imperial od in fraction of inch wall thickness is thousands of an inch. Metric Od mm teo decimal places

Question 36

Tube fittings syle 3x

Answer 36

Flared Welded or brazed Flarless

Question 37

Standard flare angles are

Answer 37

45 low pressure 37 high pressure

Question 38

Flarless fittings developed for

Answer 38

Thick walled tubing

Question 39

Hose classification 2x

Answer 39

Pressure Vacuum

Question 40

The inlet hose on a pump is a

Answer 40

Vacuum hose

Question 41

Pressure hose rating have a ______ pressure and a ______ pressure given in ___ or

Answer 41

Bursting and a working pressure rating given in psi or megapascals 1 mpa= 145 psi

Question 42

Vacuum hose rated in _____

Answer 42

Mercury normal practice to specify 28 inches of Mercury witch is full vacuum.

Question 43

Hose is sized by ___ Pressure hose Vacuum

Answer 43

ID Dash number In 16th Fraction of inch

Question 44

Hose fitting types

Answer 44

Jic Orb Npt

Question 45

1 Gallon to inches

Answer 45

1 x 231 = 231 "

Question 46

Jic means

Answer 46

Joint Industry Conference

Question 47

Hydraulics tank are made of

Answer 47

9-11 gauge steel that has been picked and oiled

Question 48

A baffle serves what purpose 4x

Answer 48

Prevents turbulence Promotes cooling Promote settling of contaminants. Allows air to escape from fluid to reduce foaming

Question 49

Breather on tank allows

Answer 49

Air to flow in and out as fluid level rises and falls Prevents to low cavitation Too high aeration

Question 50

Inlet filter _____ microns

Answer 50

100

Question 51

3 common types of reservoirs

Answer 51

Open Pressurized Closed- circuit.

Question 52

Open reservoir size

Answer 52

2 to 3 times pump capacity

Question 53

If open resivorirs vent to the atmosphere, how do pressurized and closed deal with atmosphere

Answer 53

They are sealed from atmosphere and use a supply of regulated low pressure air 1-3 psi above atmosphere.

Question 55

In a closed circuit reservoir most of return flow goes

Answer 55

Directly back to pump from actuator

Question 56

Closed circuit reservoir size

Answer 56

Small reservoir only 15 percent goes back to tank.

Question 57

Resevoir mounting styles 4x

Answer 57

Flat top L shaped Overhead stack Vertical mount

Question 58

Partical counter is set

Answer 58

4,6,14 micron

Question 59

4 locations for filters in a hydraulic system

Answer 59

Pump inlet Pressure line immediately after the pump Return line Off line

Question 60

Locating leaks 3 steps

Answer 60

1. Clean area watch for the leak. 2. Focus on fittings first then hoses and seals. 3. Suspect the fitting that is most difficult to get at would have been hardest to tighten.

Question 61

Minor leaks can cause

Answer 61

Ingested contamination.

Question 65

Dirty gritty oil acts as

Answer 65

A grinding compound

Question 66

Air in system causes

Answer 66

Rapid wear in working parts and generation of heat is the result.

Question 67

Positive seals are

Answer 67

Seal that does not allow any leakage Eg . Flat gasket O ring between stationary surfaces

Question 68

Non positive seals

Answer 68

Allow controlled leakage for lubrication Eg vane tips against cam ring Between valve spools and the bore.

Question 69

Static seals

Answer 69

Provide seal between two surfaces that do not move with respect to each other.