Pump Baseplate Resonance Responsible for Large Piping Vibration and - - PowerPoint PPT Presentation

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Pump Baseplate Resonance Responsible for Large Piping Vibration and - - PowerPoint PPT Presentation

Jul 18, 2023 185 likes •383 views

Pump Baseplate Resonance Responsible for Large Piping Vibration and Component Failures Jos A Vzquez, Ph.D. DuPont Company Engineering- Eng Mechanics Group Wilmington, Delaware Problem Statement Two overhang Centrifugal Pumps working

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SLIDE 1

Pump Baseplate Resonance Responsible for Large Piping Vibration and Component Failures

José A Vázquez, Ph.D. DuPont Company

Engineering- Eng Mechanics Group Wilmington, Delaware

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SLIDE 2

Problem Statement

  • Two overhang Centrifugal Pumps working

in parallel

  • Pumps driven by 75 hp motors, 3600 rpm
  • Over 15 years of operation, experienced

repeat failures on piping system, valves, couplings, impellers and housings

  • Routine vibration measurement for

trending do not show any discernable pattern

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SLIDE 3

Problem Statement (cont)

  • Maintenance Personnel observed high

vibration on the piping system where many

  • f the failures occurred
  • Initial thought was that piping resonance

was excited and that shook the pump

  • It had been a practice to tighten the pipe

hanging supports to reduce vibration temporarily

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SLIDE 4

Problem statement (cont.)

South Pump North Pump

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SLIDE 5

Vibration Measurement on South Pump Bearing Housing, Coupling End Horizontal direction

Period of 8.1 sec

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SLIDE 6

Typical collection window for vibration routes 60000 CPM, 800 Lines, 4 Averages, 50% overlap

Vibration Measurement on South Pump Bearing Housing, Coupling End Horizontal direction

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SLIDE 7

Vibration Measurement on South Pump Bearing Housing, Coupling End Horizontal direction

FFT on 5 minutes worth of data. 153600 lines, 0.00333 Hz resolution

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SLIDE 8

Vibration Measurement on South Pump Bearing Housing, Coupling End Horizontal direction

South Pump North Pump Zoom around Pump running speed. 0.00333 Hz resolution

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SLIDE 9

Vibration Measurement on South Pump Bearing Housing, Coupling End Horizontal direction

South Pump Only North Pump Only Both Pumps

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SLIDE 10

Vibration Measurement on South Pump Bearing Housing, Coupling End Horizontal direction

South Pump. North Pump is Off

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SLIDE 11

Vibration Measurement on South Pump Bearing Housing, Coupling End Horizontal direction

North Pump. South Pump is Off

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SLIDE 12

ODS of the pumps

North Pump

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SLIDE 13

ODS of the pumps

South Pump

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SLIDE 14

Vibration Analyses

  • All Vibration at running speed (1X)
  • Previous attempts at balancing did not

yield any significant improvements

  • Maintenance Personnel thought the

problem was a piping resonance

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SLIDE 15

Impact Testing

  • Impact testing on the Inlet and discharge

piping did not show any resonance in the vicinity of running speed

  • Based on the evidence from the ODS, the

baseplate was impacted in several

  • directions. We found a natural frequency
  • n the baseplate of the south pump at the

running speed of that pump.

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SLIDE 16

South Pump Baseplate resonance

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SLIDE 17

Repairs

  • Repaired the pump pad that had some

cracks

  • Changed the in-house baseplate for a

fabricated baseplate that could be grouted in

  • Corrected the local practice of tightening

the pipe hangers to control vibration

  • The pumps have been in operation for 5

years without major issues

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SLIDE 18

Current Look of the Pump Installation