John crane_couplings-selection Presentation.pdf

couplings-selection

1. Coupling Selection

2. Contents
Essential Information Required
Service Factors
Coupling Ratings
Choosing a coupling arrangenment
Question Examples
Additional Checks
Special requirements
Selection Tools

3. Coupling Selection
Driver Machine
Driven Machine
Power (HP or kW ) Normal
•Max. Transient or Torque (Nm or lbs.ft) if available
Speed (rpm) Normal
•Maximum if available
Distance between shaft ends (DBSE) (mm or inches)
Driving and Driven shaft types and diameters
Essential Information for selection

4. Select a suitable SERVICE FACTOR
In coupling design the basic stress analysis considers
the Steady- torque condition.
Time

5. SF=3
Time
2. Cyclic Torque
(eg. Reciprocating comp.)
Time
SF=1
1. Steady Torque
(eg. Centrifugal compressor)
Select a suitable SERVICE FACTOR
Knowing the DRIVEN & DRIVING machinery
What is a service factor ?
•A multiplication factor applied to the nominal rating which allows for
CYCLIC TORQUE applied by certain machinery.

6. Service Factors
LOAD CLASSIFICATIONS: SERV. FAC.
Continuous & uniform operation 1.0
(Infrequent starts/ Low starting torques)
Continuous operation with minor torque 1.5
fluctuations or frequent start/stop cycles
Torque loading varies during operation in 2.0
conjunction with some shock loading
Substantial torque fluctuations & heavy 2.5
shock loads

7. Allowable alternating Torque

450
500
600
700
800
Stress range (Mpa)

Fatigue limit
10
3
10
4
10
5
10
6
10
7
10
8
10
9

Number of Cycles

400
Time
Stress
Stress
range
Tension (+)
Compression (-)
0
S-N Curve

8. Modified Goodman Diagram
0
200
400
600
800
1000
1200
0 500 1000 1500
Steady stress
Alternating stress

9. Modified Goodman Diagram
0
200
400
600
800
1000
1200
0 500 1000 1500
Steady stress
Alternating stress

10. Steady stress
Alternating stress

MEAN TORQUE
(MAX)
SPEED
(MAX)
(MAX) AXIAL
DEFLECTION
FRETTING LIMIT
RATED
OPERATING
POINT
Modified Goodman Diagram

11. Determine Coupling RATING
Determine the coupling Rating in kW/1000 rpm from the
following formula:

Given: Power (kW) and Speed (rpm)
Rating = kW x 1000 x SF
N

where
SF is service factor
kW is power rating
N is shaft speed

12. Choose Coupling Arrangement
The coupling arrangement will depend upon:
•available DBSE (distance between shaft ends)
•bearing arrangement of the coupled machines
•allowable overhung moment
•mating interfaces with the shafts
•special features required

13. Choose the coupling arrangement
required to suit the application
SINGLE BANK NON-SPACER
COUPLINGS

•LDE0, LSE0, MHSO

CLOSE COUPLED ARRANGEMENTS

•MODO, LDEC, LSEC



•TSKC, TSNC, TSRC, TSE1

14. Choose the coupling arrangement
required to suit the application

STANDARD SPACER COUPLINGS
•MHSS,
•LSES, TSKS, TLKS, TSCS, TLCS
•TSJE; TLJE; TTJE


MINIMUM OVERHUNG MASS

•TSGE, TLGE, TTGE
•TSDE, TLDE, TTDE

15. Bearing arrangements
Equipment design
X X X
3 Bearing
X X X X
4 Bearing
X Bearing

16. Misalignment and 3 Bearing System
X
X X
Parallel offset
X X
X
Converted to angular
X Bearing

17. 4 bearing systems and misalignment
X X X X
Parallel offset
X X X X
Converted to angular at each end
X Bearing

18. 3 bearing systems
•Angular and axial misalignment only
• Requires one flexing plane (1 membrane pack)

4 bearing systems
•Angular, axial and parallel misalignment
•Requires two flexing planes (2 membrane packs)
•Increase in flexing plane separation (distance between
membrane packs) increases parallel misalignment
capability
3 and 4 Bearing Systems – The difference

19. Misalignment Capability
Non Spacer
Spacer
Axial and Angular
Misalignment Only
Axial, Angular and Lateral
Misalignment

20. Question 1
Steam Turbine to Centrifugal Compressor
6MW @ 10000 RPM




What is the required rating?

21. Answer to Question 1
Required Rating = kW x 1000 x SF
N

Rating kW/1000 rpm = 6000 x 1000 x 1.0
10,000

= 600 kW/1000 rpm

22. Choose Coupling Arrangement
The coupling arrangement will depend upon:
•available DBSE (distance between shaft ends)
•bearing arrangement of the coupled machines
•allowable overhung moment
•mating interfaces with the shafts
•special features required

23. Decide on the type of disc design
‘T’ series is the prime selection unless otherwise specified.
‘T’ series maintains the drive on disc failure through emergency drive
collars.
‘M’ series disconnects the drive on disc failure.
For API 671 requirements generally use ‘T’ series.

24. Choose the coupling arrangement required
to suit the application
SINGLE BANK NON-SPACER COUPLINGS
•LO, MHSO



CLOSE COUPLED ARRANGEMENTS
•MODO
•TSRC, L***-*C, TSKC, TSKD

25. Choose the coupling arrangement required
to suit the application

STANDARD SPACER COUPLINGS
•MHSS, MODS
•L Series, TSKS, TLKS,
•TSJE; TLJE; TTJE


MINIMUM OVERHUNG MASS
•TSGE, TLGE, TTGE
•TSDE, TLDE, TTDE

26. Coupling size
From the appropriate catalogue select the coupling for the
calculated rating.
Always select a coupling with a higher rating:
eg.
Calculated rating: 211kW/1000rpm
Select: TSKS 0230

27. Question 2
Electric Motor to Screw Compressor
1500KW @ 3000 RPM




What is the rating?
Select a coupling

28. Answer to Question 2
Required Rating = kW x 1000 x SF
N

Rating kW/1000 rpm = 1500 x 1000 x 1.5
3,000

= 750 kW/1000 rpm

Select a TLKS-0750 or L081

29. SERVICE FACTOR for TRANSIENT
TORQUE
Standard couplings are suitable for transient torques as follows:
•M-series up to 3 times continuous rating.
•TSK up to 2.5 times continuous rating.
•TLK up to 2 times continuous rating.
•High Performance up to 2 times continuous rating.

To calculate the required coupling rating for Transient torque
Required Rating = Transient torque/f
where f is the factor given above

Example: Generator drive has a transient torque of 7 x nominal rating.
For TLKS selection the minimum service factor is 7 / 2 = 3.5

30. Steam Turbine to Generation set through a 3:1 ratio
Steam Turbine 5MW @ 5400rpm
Generator set 5 x Continuous torque



Select gearbox to generator coupling
Question 3

31. Answer to Question 3
Steam turbine 5MW @ 5400rpm = 5000kW @ 5400rpm
Generator 5000kW @ 5400/3 = 1800rpm
Steady duty SF generator = 1.5
Prime Mover, steam turbine = no change BUT
Gearbox present so minimum SF = 1.25
Required Steady service factor = 1.5

32. Answer to Question 3
Generator Transient torque = 5 x steady torque
TLKS coupling transient capacity = 2 x rating
Required Transient service factor = 5 / 2 which gives
worst case is TF = 2.5
Required Rating = kW x 1000 x SF
N
Rating kW/1000 rpm = 5,000 x 1000 x 2.5
1,800
= 6944 kW/1000rpm (for transients)

Need TLKS- 8500

33. Additional checks
Speed
•Check that the application maximum speed is within the
permitted range for the coupling.
Dimension
•Check that the hub maximum bore is adequate for each
shaft. Use a large hub or use a larger coupling if
necessary.
•Check that the shaft end separation [DBSE] is acceptable
for the design chosen.

34. Coupling Selection
Shaft end types
Cylindrical (Straight) with key
W
Key height
Keyway height
(hub)
Keyway height
(shaft)

35. Coupling Selection
Shaft end type
Conical (Tapered) with key
Required counter bore
or across corners of
shaft nut
Taper
(Ratio, in/ft or degree)
Key details
 Size
 Parallel to taper or
centerline

36. Question 4
Electric Motor to Centrifugal Pump
Motor shaft - Parallel B + K
Pump shaft - Taper B + K Dia 36 @ large end
Shaft end separation 100mm
Power absorbed by pump 17KW
Motor Speed 2980
Selection + Assumptions made + Limitations

37. Answer to Question 4
Duty Conditions
17kW @ 2980rpm; DBSE =100:
Is pump centrifugal? If so assume SF = 1
Rating kW/1000 rpm = 17 x 1000 x 1.0 = 5.7 kW/1000 rpm
2,980
Select either
>> MHSS-0006 or L001 or TSKS-0013
Pump shaft diameter = 36 mm taper OK for TSK and MHS, but L series
Re-select L003
Motor shaft diameter = ?? STATE maximum for selection
Clarify requirement.

38. Question 5
Motor 1500KW @1500 rpm 220 shaft
Gearbox 2.6 : 1 increasing, motor side 200 mm diameter
145mm pump side.
DBSE 200mm motor side, 140mm DBSE pump side
AP1 610 Select High speed coupling

39. Answer to Question 5
Motor 1500kW at 1500rpm
Gearbox increasing pump speed to 1500 x 2.6 = 3900rpm
Shaft diameter GearBox(driver) = 145 mm
Pump shaft diameter = 140 mm
DBSE = 200mm

1500 x 1000 x 1.25
3900
TLKS-0750-0078-2000

40. Required Misalignment
•Axial Misalignment (in / mm)
•Angular deflection deg
•Parallel Offset (in / mm)
Industrial or Customer specifications apply?
•(API 610, API 671, etc.)
Is this a new or retrofit application?
•If retrofit, obtain mass elastic data of original coupling
Special requirements
Coupling Selection

41. Enquiry form Shaft Length Shaft Length
B & K
(driver)
B & K
(driven)
DRIVER
END
DRIVEN
END
D.B.S.E
 
Tol
Shaft LengthShaft Length
Recess Diameter
TAPER KEY DETAILS
Parallel To Axis
Parallel To Bore
TAPER BORE DETAILS
End: Large / Small
Shaft:  Tol
Taper Angle:
DRIVER / DRIVEN
END
DRIVER / DRIVEN
END
B & K
(driver / driven)
B & K
(driver / driven)

D.B.S.E
Recess Depth
TAPER KEY DETAILS
Parallel To Bore
Parallel To Axis
TAPER BORE DETAILS
Shaft:  Tol
Taper Angle:
B & K
(driver)
Shaft Length
Recess Depth
Recess Depth
D.B.S.E
Recess Diameter
Recess Diameter
DRIVER
END
DRIVEN
END
Shaft Length
B & K
(driven)
TAPER KEY DETAILS
Parallel To Bore
Parallel To Axis
Taper Angle:
Shaft:  T ol
End: Large / Small End: Large / Small
TAPER BORE DETAILS
METASTREAM COUPLING ENQUIRY
ENQUIRY REF:CUSTOMER:
PLANT / CONTRACT REF:
CONTACT: DATE:
FAX: PHONE: E.MAIL
SELECTION DATA
DRIVING MACHINE: DRIVEN MACHINE:
DRIVER RATING: kW / HPDUTY SPEED: rpm
SHAFT END SEPARATION (DBSE)
mm / in
SERVICE: (e.g. cooling water pump)
AMBIENT
TEMPERATURE
-15
o
C to + 150
o
C YES NO
IF NO - PLEASE SPECIFY
o
C /
o
F
APPLICABLE
SPECIFICATION
API 610 API 671 NONE
IF API 610 OR 671 PLEASE SPECIFY EDITION:
OTHERS (PLEASE SPECIFY)
PREFERRED COUPLING TYPE
OPTIONAL FEATURES (PLEASE TICK). PLEASE SPECIFY BALANCE GRADE IN BOX GIVEN
TAPPED PULLER HOLES PROFILED HUBS AXIAL ADJUSTMENT
INSULATED SPARK RESISTANT LIMITED END FLOAT
TRIM BALANCE HOLES BALANCED BALANCE GRADE G
TRANSMISSION BALANCE HUB BALANCE ASSEMBLY BALANCE
TORSIONAL TUNING SHEAR PIN FEATURE VERTICAL
REMARKS
TYPE SIZE FEATURES D.B.S.E.COUPLING
SELECTION
ORIGINATOR: DATE:
John Crane UK Ltd
Sales and Service Division
Nash Road, Trafford Park,
Manchester. M17 1SS.
Tel: [phone]
Fax: [phone] or 5910
PLEASE SUPPLY DIMENSIONS USING CORRECT SKETCH: -
Tol
Tol

42. Selection Software

43. Selection Software