Module 7.9

Question 1

how must a pipe be cut without pipe cutters? and to what length?

Answer 1

with a 32 TPI hacksaw ad a cut 10% longer than needed to allow for bends

Question 2

explain the cutting process with pipe cutters

Answer 2

align cut mark with the cutting wheel dont apply much pressure as it can deform the pipe. deburr edges by spinning clockwise.

Question 3

what size pipe can be bent by hand?

Answer 3

< 1/4’’

Question 4

where may it be beneficial to perform the pipe bending?

Answer 4

at the repair site

Question 5

how must pipe bends be made?

Answer 5

totally tension free

Question 6

what are the unacceptable defects of pipe bending?

Answer 6

wrinkled or kinked

Question 7

what are the acceptable limits of a flattened bend?

Answer 7

the smaller flat must not be less that 75% of the original size

Question 8

what is wrinkling caused by?

Answer 8

pipe being too hard or too thin

Question 9

what is kinking caused by?

Answer 9

kinking is due to the pipe being bent without internal or external support

Question 10

what is the flare angle of pipe fittings?

Answer 10

37 degrees

Question 11

what are the two types of flaring methods?

Answer 11

-impact type
- roll type

Question 12

how is a pipe flared using the impact type method?

Answer 12

plunger driven into pipe that is secured into the flaring block, with light hammer blows

Question 13

what is the preferred method of pipe flaring?

Answer 13

roll type

Question 14

single flares are manufactured to close tolerances to ensure what?

Answer 14

leak free joints

Question 15

what pipes can be double flared?

Answer 15

smaller than 3/8’’ and made of soft aluminium

Question 16

what flare provides the best seal and is more resistant to shearing effect of torque?

Answer 16

double flare

Question 17

what are the two tools used to form the double flare?

Answer 17

upsetting tool and flaring tool

Question 18

how is a harrison type connection fitted?

Answer 18

a tool inserted which widens the pipe into the fitting

Question 19

harrison fittings are best suited to what pipes and give what benefits?

Answer 19

-thin walled pipes
-almost completely vibration resistant

Question 20

how is a permaswage fitting fitted and can it be removed?

Answer 20

steel sleeve squeezed onto the pipe with a hydraulic tool. Permasage fittings can only be cut out.

Question 21

what is advantageous about a perma swage fitting?

Answer 21

installed quickly, lightweight and gives a good seal.

Question 22

when would pipe belling be used?

Answer 22

rigid piping carrying low pressure fluids or air can be connected to rubber hoses with a screw type hose clamp

Question 23

what sizes of pipe can be belled by hand?

Answer 23

1 inch

Question 24

how are pipes and hoses marked?

Answer 24

identify application and spec by:
-words
-colour
-symbol

Question 25

what are the benefits of using high quality pipe materials?

Answer 25

thinner walls and less flow resistance

Question 26

what are high pressure lines typically made from?

Answer 26

steel lines

Question 27

medium and low pressure lines are made of what to save weight?

Answer 27

aluminium

Question 28

hoses for engine and hydraulic systems use what plastic?

Answer 28

PTFE

Question 29

what are the benefits to the use of PTFE?

Answer 29

-chemically inhert -unaffected by synthetic oils and fluids -no shelf life -satisfactory at high fluid and ambient temps

Question 30

PTFE is more vulnerable to what?

Answer 30

vulnerable handling

Question 31

how are hoses identified?

Answer 31

info printed on hose (lay line) can also be on a tab or band

Question 32

if a pipe of the same material is not available aluminium pipes should be repaired with what?

Answer 32

CRES or titanium alloys

Question 33

what are CRES and titanium pipes repaired with?

Answer 33

cres should be repaired with titanium titanium should be repaired with CRES

Question 34

on aluminium, what is the max depth of a scratch or nick allowed? and how is this repaired?

Answer 34

10% wall thickness and should be repaired with hand tools

Question 35

what is the acceptable limit of a pipe dent?

Answer 35

20%

Question 36

where are defects not allowed?

Answer 36

in the heel of a bend

Question 37

what are the damage limits for thin walled CRES and titanium pipes

Answer 37

less than aluminium

Question 38

where are cracks or deformities not acceptable?

Answer 38

on a flare

Question 39

what are the limits for sharp bottom defects and impact traces?

Answer 39

-5% pipe wall thichness for defects -impact traces not permitted

Question 40

what are the limits for round bottom defects and impact traces?

Answer 40

-10% pipe wall thickness for defects -2% dia. for impact types

Question 41

what are the hose pressure ratings?

Answer 41

-low up to 600psi -medium up to 3000psi - high over 3000psi

Question 42

what test must be conducted on a hose before service?

Answer 42

1.5 times system pressure capping on one end

Question 43

what should be considered when installing a hose?

Answer 43

-no twist -minimum flex - not stretched - minimum bend radius radius observed

Question 44

how often should a hose support be placed?

Answer 44

every 60cm

Question 45

how can you replace a short bend radius?

Answer 45

an elbow fitting

Question 46

how is the minimum permissable bend radius determined?

Answer 46

pressure, hose type and nominal size

Question 47

clamps are used for what?

Answer 47

-to stop twisting - danger from vibration, long lengths or sharp edges.

Question 48

protective sleeves are used to protect from heat and abrasion, what are the different types of sleeving?

Answer 48

-heat shrink - nylon spiral wrap, - teflon

Question 49

what must inspections look for?

Answer 49

any signs of pipe chafing, loose connections, pipe/ hose separation

Question 50

what is a dimension in if it is not stated?

Answer 50

inches

Question 51

fluid lines are not allowed to chafe against what?

Answer 51

control cables, structure, wire bundles, conduits carrying wires

Question 51

clamps utilising teflon are used when?

Answer 51

areas with contamination of fuel or hydraulic fluid

Question 52

what are the two most common clamps?

Answer 52

plain clamp rubber cushioned clamp

Question 53

bonded clamps secure what?

Answer 53

fuel oil and hydraulic wires made from metal

Question 54

what is special about bonded clamps?

Answer 54

they are gounded to the structure

Question 55

how is an O-ring and thread in O-ring side lubricated

Answer 55

specified hydraulic fluid

Question 56

when must lubricant never be applied?

Answer 56

on the female thread, and contact surface between sleeve and sealing surface.

Question 57

on a swivel bulkhead fitting, what is done before applying torque to the locknut on the fitting?

Answer 57

the pipe sleeve nuts are connected and torqued

Question 58

what shows the pipes ends are correctly aligned

Answer 58

the nut spins freely on the thread

Question 59

what must be done before torqueing the end of a fitting?

Answer 59

connect and tighten by hand

Question 60

what must be done when attaching a hose?

Answer 60

don't twist and don't tighten clamps until the installation is finished.

Question 61

what must all runs of pipe have before fittings?

Answer 61

at least one bend to absorb forces.