Centrifugal Pumps vibrations limits.pdf

Centrifugal Pumps Vibration Causes of Mechanical Vibration

Main causes of mechanical vibrations are:            

Bad bearings Shaft beanding Unbalanced rotor Misalignment Soft foot Clogged Impeller or suction line Piping stresses Thermal growth of pump parts Looseness of foundation bolts and maximum impeller size Operating pump at other than best efficiency point (BEP) Internal recirculation recirculation Water hammer.

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Vibration causes

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 Noise  Turblance in pumps  Premature failures of pump parts etc

This documents carries vibration limits of centrifugal pumps according to various standards and way to measure vibration according to API-610 Eleventh Edition

Vibration limits for Centrifugal Pumps S/N o

1

2

3

Standard

ANSI/API STANDARD 610 ELEVENTH EDITION, SEPTEMBE R 2010

ANSI B-73

ISO 9908 Technical specification for centrifugal  pumps  –  Class 3

Pump Type

Location of vibration measure ment Pump

Over hung and Between Bearing

Bearing Housing

verticallysuspended

Pump thrust  bearing housing or motor mounting flange

End Suction

single stage, multistage, horizontal or vertical constructio n (coupled or close coupled)

Bearing Housing

Antifriction Bearing Type

For all types

For all types

RPM'S

Load (KW)

Other Parameters

Vibration RMS (mm/sec)

Vibration Peak (mm/sec)

Up to 3600 RPM

Up to 300 KW (400 hp)

 N/A

3

4.24

 N/A

5

7.07

Less than 20HP (15 KW)

 N/A

3

4.24

More than 100HP (75 KW)

 N/A

4.6

6.5

Centerline heights  below 225 mm (Height from base plate to shaft centerline for horizontal  pump)

2.8

3.95

4.5

6.36

4.5

6.36

7.1

10.04

Rigid Horizontal = 3.0 Flexible horizontal = 5.50 All Vertical = 7.10 Rigid Horizontal = 4.5 Flexible horizontal = 7.10 All Vertical = 7.10

Rigid Horizontal = 4.24 Flexible horizontal = 7.70 All Vertical = 10.04 Rigid Horizontal = 6.36 Flexible horizontal = 10.04 All Vertical = 10.04

Vibration at any flow within the pump's  preferred operating region

N/A

Up to 1800 RPM

Bearing Housing

For all types

Between 1800 RPM and 4500 RPM

4

ISO 5199

single stage, multistage, horizontal or vertical constructio n

Bearing Housing

 N/A

For all types

with any drive and any installatio n for general applicatio n

 N/A

with any drive and any installatio n for general applicatio n

Centerline heights above 225 mm (Height from base plate to shaft centerline for horizontal  pump) Centerline heights  below 225 mm (Height from base plate to shaft centerline for horizontal  pump) Centerline heights above 225 mm (Height from base plate to shaft centerline for horizontal  pump) Centerline heights  below 225 mm (Height from base plate to shaft centerline for horizontal  pump) Centerline heights Above 225 mm (Height from base plate to shaft centerline for horizontal  pump)