Getting started with condition monitoring for only $2000
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This document discusses how condition monitoring can be done for low cost using simple methods and techniques. It provides 10 case studies as examples of low-cost condition monitoring, such as using a $10 tool to view a damper around a bend, using a ruler to measure liner erosion depth, and using temperature sensitive paint or a spot temperature indicator. Overall vibration monitoring can be done for as little as $300. It emphasizes that proper documentation of measurement methods is important.
Getting started with condition monitoring for only $2000
- 1. GETTING STARTED WITH CONDITION MONITORING FOR ONLY $2,000? Ray Beebe (Bitten by the CM bug in 1964!)
- 2. CM IS POWERFUL Can be costly to do properly with depth Cost can deter smaller companies (or even big over-thrifty ones!) BUT, much can be done for low cost All depends on the mode of degradation…..
- 3. CASE 1: DEGRADATION OF “INVISIBLE” DAMPER Situation: duct, with hot gas 1000degC CM – view damper around bend and assess condition: Will it last until next repair opportunity? Cost of viewing tool: $10?
- 4. CASE 2: LINER EROSION Coal mill casing liners erode in varying pattern of grooves Changeout is needed, but wear rate varies, so routine change may mean changeout is too early. Simple CM – straightedge and rule to get depth of deepest valley. Plot vs service time Cost nil (Note: must carefully spell out in Job Card how measurement is taken. Previous method showed liners apparently “growing”)
- 5. CASE 3: FAN EXCESSIVE VIBRATION Fan handling hot damp dirty gas. High vibration hot, also high when cold! Much investigation looking for complex cause – and then……
- 6. LOOSENESS OF BEARING ASSEMBLY Vibration difference on concrete shows loose bolts
- 7. CASE 4: FAN UNBALANCE DUE TO DEPOSITION Moist dust sticks unevenly on fan blades Unbalance results Overall vibration goes up! Manual readings and trending cost little, BUT define and mark test points……
- 9. CASE 4: CONTINUED Moist dust sticks unevenly on fan blades Unbalance results Overall vibration goes up! Manual readings and trending cost little…… Solution: balancing the fan is expedient, or clean it Re-design to eliminate cause: not practicable here Overall vibes are OK if this is the only problem encountered
- 10. CASE 5: PUMP NEAR RESONANCE High vibration – so high that outlet valve wobbled shut! Stiffening easy to try - and it worked! (Worth a try. If NBG, then further investigation needed)
- 11. ISO GUIDELINES – EXPERIENCE HELPS OK NOT OK
- 12. VIBRATION OVERALL – MANY INSTRUMENTS AVAILABLE
- 13. TRY EBAY! E.G. $300 S/H Ack: P Todd
- 14. VIBRATION OVERALL- THE WEDGY Make triangle of card, vertical side 2.5mm (i.e. 2500µm), horizontal side 25mm. Carefully mark 10 even graduations on base 0 1 2 3 4 5 6 7 8 9 10 Amplitude Fix on machine with short side in direction of vibration. Persistence of vision shows double image: cross-over point shows vibration amplitude. For high vibration of crude machines!
- 15. TURBINE SUPERVISORY INSTRUMENTATION On bearing in line with the centreline? Does that matter?
- 16. CASE 6: CASING DISTORTION - 350MW TURBINE GENERATOR HP P LP B Generator Journal bearings Couplings LP AHP-IP
- 17. CASE 6: WHAT TSI RECORDS SHOWED
- 18. CASING DISTORTED, PULLED ROTORS OUT OF LINE Unit was below half full load, but cooling water flow was not reduced, despite ops instructions. Pressure too low- casing distorted If ops rules had been kept…
- 19. CASE 7: BUT, WHAT IS TSI MEASURING? Air gap to actual bearing
- 20. TSI: NON-CONTACT DISPLACEMENT BETTER THAN SHAFT RIDERS OR BEARING CAP
- 21. OVERALL + BEARING CONDITION Velocity Frequencies around rotation order: Overall machine condition Unbalance, temporary and permanent Looseness Misalignment Acceleration and ultrasonics Higher frequencies: Rolling element bearing condition
- 22. CASE 8: RE BRG Acceleration level trend showed bearing degrading Acceleration spectrum showing bearing frequencies
- 23. Selected Spot Ack: P Todd Ultrasonics
- 24. TEMPERATURE INDICATION Thermography, yes – use iPhone adpator? Spot temperature indicator may be enough: cheap Temperature sensitive paint
- 25. CASE 9: GOT A DCS? STEAM TURBINE INTERNAL DAMAGE: INFO FOR “FREE”
- 26. Main steam strainer blockage Blockage in blading
- 27. CASE 10: DCS FOR MAJOR PUMPS Boiler Feed Pump 7000kW 3 × 50%: run all three combinations: if two sets show low, the most worn pump is the one common to both
- 28. OR, TAKE DATA FROM HISTORIAN Head …then follow procedure for optimisation (see Ray’s book and papers)
- 29. WEAR PARTICLE ANALYSIS Lube sampling pump: oil samples for both on-site and lab CM
- 30. CM & DEFECT ELIMINATION Understand defect levels in CM parameters Record experience- what was found vs what was predicted Understand key defect causes when a CM parameter changes Take immediate action to eliminate or slow Use defect understanding to improve the quality of repair tasks Use baseline measurements on equipment start-ups Post overhaul CM checks Understand defect and causes through equipment post mortems. Design out where justified!
- 31. IMPROVING CONDITION MONITORING SYSTEMS Better use of simple equipment inspections & simple CM techniques More use of Defect Elimination (Get proactive) Greater involvement of non-CM specialists Increase efficiency of CM data analysis Better prognosis
- 32. Simple methods often enough VITAL: define clearly how measurements are taken, stored, action outcome. More complex machines deserve more complex approach Email me for papers on case studies Happy monitoring! r.beebe@federation.edu.au