Introduction Couplings Types Presentation.pdf

Introduction Couplings Types

1. Flexible Co
up
lin
g
s
up g
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Prepared by: Fraz

2. CONTENTS
•
Purpose of Coupling
•
Types of Couplings
•
Rigid Couplings
•
F
u
n
ct
i
o
n
s

o
f Fl
e
xi
b
l
e

coup
lin
g
uctoso ebecoup g
•
Types of Flexible Couplings
•
Coupling selection chart Coupling balancing requirements
•
Coupling balancing requirements
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3. PURPOSE OF COUPLING PURPOSE OF COUPLING
The coupling must be capable of
•
Transmitting design torque.
•
Ope
r
at
in
g

at
m
a
xim
u
m
co
n
t
in
uous

speed
Ope at g at a u co t uous speed
•
Handling speed and load transients
•
Having minimum reactions on the drive system system
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4. TYPES OF COUPLINGS TYPES OF COUPLINGS
•
TYPES OF COUPLINGS:
1.
Rigid Couplings
2.
Fl
e
xi
b
l
e

Coup
lin
gs
ebeCoup gs
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5. TYPES OF RIGID COUPLINGS: TYPES OF RIGID COUPLINGS:
Rigid Cylinder:
ƒ
The cylinder can be solid , or ribbed. The cylinder can be solid , or ribbed.
ƒ
A key is always used that spans keyways
machined in both shafts.
Rigid Flanges: Rigid Flanges:
ƒ
Coupling halves are keyed onto the shafts, and then the flanges are bolted shafts, and then the flanges are bolted together.
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7. FUNCTIONS OF FLEXIBLE COUPLINGS FUNCTIONS OF FLEXIBLE COUPLINGS
•
Following are the functions of a flexible coupling coupling
1.
Transmit Power
2.
Accommodate misalignment
3
Allow axial displacement
3
.
Allow axial displacement
4.
Insure no loss of lubricants in grease
packed couplings.
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8. FUNCTIONS OF FLEXIBLE COUPLINGS FUNCTIONS OF FLEXIBLE COUPLINGS
5.
Easy to install and disassemble
6
Accept torsional shock and dampen
6
.
Accept torsional shock and dampen torsional vibration
7.
Stay rigidly attached to the shaft.
8.
Withstand temperatures of environment or
heat of friction
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9. TYPES OF FLEXIBLE COUPLINGS
•
TYPES OF FLEXIBLE COUPLINGS:
1.
Mechanical Element
2.
Elastomeric Element
3
.
M
eta
lli
c
M
e
m
b
r
a
n
e

/
Di
s
k T
ype
3
eta c e b a e / s ype
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10. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
Chain Couplings:
ƒ
Two gear sprockets with hardened Two gear sprockets with hardened sprocket teeth connected by a double
width chain
ƒ
Capacity : 3000 hp @ 1800 rpm Capacity : 3000 hp @ 1800 rpm
ƒ
Max Speed : up to 5000rpm
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11. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
Chain Couplings: Advantages: Advantages:
ƒ
Easy to disassemble and reassemble
ƒ
Fewer number of parts Disadvantages: Disadvantages:
ƒ
Speed limited due to difficulties in
maintaining balancing requirements
ƒ
Requires lubrication
ƒ
Requires lubrication
ƒ
Limited allowable axial displacement
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12. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
Gear Couplings: The gear coupling consists of two hubs
ƒ
The gear coupling consists of two hubs with external gear teeth that are attached
to the shaft
ƒ
A hub cover or sleeve with internal gear teeth engage with the shaft hubs to p
rovide the transmission of
p
ower
pp
ƒ
Lubrication of gear teeth is required.
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14. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
G Cli G
ear
C
oup
li
ngs:
ƒ
Capacity : up to 70,000 hp M
Sd
t
50
000
ƒ
M
ax
S
pee
d
:up
t
o
50
,
000
rpm
ƒ
Backlash should be minimum and will be in
accordance to the permissible misalignment
Cli
bl
hld
h
ii
ƒ
C
oup
li
ng assem
bl
ys
h
ou
ld
h
ave m
i
n
i
mum
6mm of axial displacement
ƒ
Hardness of gear teeth<45Rc (Rockwell)
Cli
d
hld
b
i
ti ht
ƒ
C
oup
li
ng guar
d
ss
h
ou
ld
b
ea
i
r
ti
g
ht
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15. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
Gear Couplings: Torsional Tuning
ƒ
Shifting of one or more torsional natural frequencies of a coupled system to avoid frequencies of a coupled system to avoid system resonance at a known excitation
ƒ
Torsional tuning is accomplished by varying th t i l tiff f th li th
e
t
ors
i
ona
l
s
tiff
ness

o
f th
e

coup
li
ng
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16. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
Gear Couplings: Advantages:
ƒ
Allows freedom of axial movement Capable of operating at high speeds
ƒ
Capable of operating at high speeds
ƒ
Low overhung weight
ƒ
Good balance characteristics. L hit f fl liti
ƒ
L
ong
hi
s
t
ory

o
f
success
f
u
l
app
li
ca
ti
ons
Disadvantages:
ƒ
Requires lubrication.
ƒ
Separation of greases into soaps and oils.
ƒ
Centrifugal effect on oils / sludge formation.
ƒ
Tem
p
erature limitation due to lubricant
p
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17. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
Gear Couplings: Th l t t th i
ƒ
Th
ere

are

on
l
y
t
wo
t
ee
th i
n

contact when misalignment is
present ƒ
The remainder have a gap
ƒ
The remainder have a gap between each tooth set as shown in fig.
ƒ
In center of this picture the In center of this picture the tooth is in pivoted position.
ƒ
At edges of this picture teeth are in ‘tilted’ position. 2
D FEA d l t 0”
ƒ
2
-
D FEA
mo
d
e
l
a
t 0”
misalignment.
ƒ
2-D FEA model at 2” misalignment misalignment
.
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18. METALLIC ELEMENT COUPLING: METALLIC ELEMENT COUPLING: Metal Ribbon Couplings:
ƒ
Consist of two hubs with axial ‘grooves’ on th t di t f th hb th
e

ou
t
er
di
ame
t
er

o
f th
e
h
u
b
ƒ
A continuous ‘S’ shaped grid meshes into
the grooves.
ƒ
Misalignment and axial movement is achieved by flexing and sliding of the grid member member
ƒ
Lubrication of gear teeth is required.
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19. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
Metal Ribbon Cou
p
lin
g
s:
pg
ƒ
Grid is fabricated from hardened, high strength
steel. ƒ
Capacity : up to 70 000 hp / 100 rpm
ƒ
Capacity : up to 70
,
000 hp / 100 rpm
ƒ
Max Speed : to 6000rpm
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20. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
Metal Ribbon Couplings: Advantages:
ƒ
Easy to assemble and disassemble.
ƒ
Long history of successful applications. Long history of successful applications.
ƒ
Torsionally soft.
Disadvantages:
ƒ
Requires lubrication.
ld
ƒ
Temperature
l
imite
d
.
ƒ
Speed limited
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21. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING: Flexible Link Coupling
ƒ
The flexible link coupling utilizes a series of
cross laced, metallic links with one end of
h li k tt h d t di t d
eac
h li
n
k
a
tt
ac
h
e
d t
o

a
di
sc

moun
t
e
d
on

the driver shaft, and the other end of each link attached to a disc mounted on the driver shaft driver shaft
.
ƒ
The links are matched in pairs so that when one is in tension, the other is in com
p
ression.
p
ƒ
Misalignment and axial displacement is accomplished by a flexing action in the series of cross links.
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22. MECH ELEMENT COUPLING: MECH ELEMENT COUPLING:
ƒ
Capacity : up to 30,000 hp
ƒ
Max Speed : up to 30,000rpm
ƒ
Shaft Bores : up to 7 in.
ƒ
Shaft Spacing: 2 to 200 in. Shaft Spacing: 2 to 200 in.
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23. ELASTOMERIC COUPLING: ELASTOMERIC COUPLING:
El t i C i El
as
t
omer
i
c
C
ompress
i
on:
ƒ
An elastomeric medium used to transmit
torque and accommodate misalignment.
ƒ
Torsionally
‘
soft
’
to absorb high starting
ƒ
Torsionally
soft to absorb high starting
torques.
ƒ
The spider is generally natural or synthetic rubber, urethane, nylon and
teflon
.
rubber, urethane, nylon and
teflon
.
ƒ
Capacity : up to 67,000 hp / 100 rpm
ƒ
Max Speed : approx. 5000rpm
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25. ELASTOMERIC COUPLING: ELASTOMERIC COUPLING:
Elastomeric Compression: Ad tAd
van
t
ages:
ƒ
Minimal wear in coupling.
ƒ
Act as vibration damper and isolator.
ƒ
Acts
as
electrical
shaft
current
insulator
Acts
as
electrical
shaft
current
insulator
.
ƒ
Torsionally soft.
ƒ
Allows axial movement and dampens axial
vibration.
N
lbi ti
id
ƒ
N
o
l
u
b
r
i
ca
ti
on requ
i
re
d
.
Disadvantages:
ƒ
Speed
limited
(Cannot
be
balanced
perfectly)
ƒ
Speed
limited
(Cannot
be
balanced
perfectly)
.
ƒ
Temp, oxidation of rubber and corrosive attack.
ƒ
Undesirable axial forces.
ƒ
Heat generation due to cyclic flexing.
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26. ELASTOMERIC COUPLING: ELASTOMERIC COUPLING:
Elastomeric Com
p
ression:
p
Failure modes:
ƒ
Abrasion:Rubber is a high friction
til d i dt i d d
ma
t
er
i
a
l
,

an
d
m
i
nor
d
us
t i
s

pro
d
uce
d
.
ƒ
Temperature deformation:
ƒ
Rubber aging (drying):
ƒ
Consumption:
Rubber and plastic are
ƒ
Consumption:
Rubber and plastic are
organic materials, and there are some
creatures that eat them
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27. ELASTOMERIC COUPLING: ELASTOMERIC COUPLING:
Elastomeric shear: Tthd h
It i t i t ll d
1.
T
oo
th
e
d
s
h
ear:
It i
s

easy
t
o
i
ns
t
a
ll
an
d
maintain, and handle large misalignment.
2.
Tire type:
T
ire beads are clamped to a hub
on either side. Torque is transmitted by
the tire in shear.
3
Friction Disk:
A rubber or suitable plastic
3
.
Friction Disk:
A rubber or suitable plastic
bonded to a steel disk is pressed against another disk.
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29. METALLIC MEMBRANE / DISK TYPE: METALLIC MEMBRANE / DISK TYPE:
Diaphragm Couplings:
ƒ
Transmission of power through two flexible metal diaphragms. metal diaphragms.
ƒ
Bolted to the outer rim of the shaft hubs
and connected via a spacer tube.
ƒ
Misalignment and axial displacement is Misalignment and axial displacement is absorbed by flexing of the diaphragm members.
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31. METALLIC MEMBRANE / DISK TYPE: METALLIC MEMBRANE / DISK TYPE:
Di h C li Di
ap
h
ragm
C
oup
li
ngs:
ƒ
Diaphragm has an effect of a spring
ƒ
Coupling
natural
frequency
does
not
match
ƒ
Coupling
natural
frequency
does
not
match
rotating speeds or harmonics in the drive
system. ƒ
Frequently
used
at
gas
turbines
and
ƒ
Frequently
used
at
gas
turbines
and
compressors.
ƒ
Capacity : up to 30,000 hp
ƒ
Max
Speed
:
to
100
000
rpm
(only
coupling)
ƒ
Max
Speed
:
to
100
,
000
rpm
(only
coupling)
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32. METALLIC MEMBRANE / DISK TYPE: METALLIC MEMBRANE / DISK TYPE:
Diaphragm Couplings: Advantages:
ƒ
Excellent balance characteristics.
ƒ
No
lubrication
required
ƒ
No
lubrication
required
.
ƒ
Low coupling weight and bending forces.
ƒ
Accepts high temperature environment. Disadvantages
:
Disadvantages
:
ƒ
Limited axial displacements and oscillation.
ƒ
Proper shaft spacing requirements.
ƒ
Excessive
misalignment
will
transmit
high
ƒ
Excessive
misalignment
will
transmit
high
loads to shafting.
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33. METALLIC MEMBRANE / DISK TYPE: METALLIC MEMBRANE / DISK TYPE: Flexible Disc Couplings
ƒ
The flexible disk cou
p
lin
g
is ver
y
similar to
pg
y
the diaphragm coupling
ƒ
Multiple, thinner discs are used as the flexing element
instead
of
circular
contoured
element
instead
of
circular
,
contoured
diaphragm elements.
ƒ
Two disc packs (or diaphragms) are needed t
dt
ll l
ili t
t
o accommo
d
a
t
epara
ll
e
l
m
i
sa
li
gnmen
t
.
ƒ
A single disc can only handle pure angular
misali
g
nment.
g
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35. METALLIC MEMBRANE / DISK TYPE: METALLIC MEMBRANE / DISK TYPE:
Flexible Disc Couplings
ƒ
Capacity : up to 65,000 hp / 100 rpm
ƒ
Max
Speed
:
up
to
30
000
rpm
Max
Speed
:
up
to
30
,
000
rpm
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36. Gear
100,000
Quill shaft
Elastomer
Inserts
HIGH POWERS &
10,000
Coil Springs
HP/100RPM
FLEXIBLE in
TORSION
HIGH

POWERS

&

SPEEDS
1
,
000
Taper Grid
Multiple
Disc
TORSION GENERAL
,
Contoured
Disc
Elastomer
100
Chain
10
Pin & Bush
1001000 50 1000050000
RPM
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37. Coupling Balancing Requirements

AGMA
Coupling Balance
Class
Maximum Potential
Displacement
(rss Microinches)
4 Over 32,000 5
32 000
5

32
,
000

6 16,000 7 8,000 8 4,000 9 2,000 10 1,000 11 500

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39. THANKS THANKS
‐thePetroStreet team
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