by Sanjay Tyagi , B. P. Thapliyal , R. M. Mathur and A. K. Ray

1. Condition Based Diagnostic Techniques for Predictive Maintenance- A key of Success to Paper Industry by Sanjay Tyagi, B. P. Thapliyal, R. M. Mathur and A. K. Ray Central Pulp and Paper Research Institute, Saharanpur

2. Purpose of Maintenance of Industry • Fundamental purpose of maintenance in any process industry is to provide the required capacity for production at the lowest cost. • Should be regarded as a RELIABILITY function , not as a REPAIR function

3. Objective of the Maintenance To achieve the correct level of operational reliability and best possible personal safety at minimum cost

4. Cost of Maintenance in Few Industries

5. Classification of Maintenance Time based Maintenance (TBM) Preventive Maintenance Condition bases Maintenance Maintenance Breakdown Maintenance or corrective breakdown

6. Corrective or Break Down Maintenance (Run to breakdown) • It covers the measures carried out in order to correct or repair faults after they have occurred. • Referred as “repair work” in everyday language. • If industry running too many in expensive machines where process duplicates , less of production is not significant as spares machines can take care off production. • In case of process industries like paper if large unduplicated process machine run to breakdown it severely affected production.

7. Time Based Preventive Maintenance Plant management decides to take some actions with the aim of preventing failure occurring or at least reducing the chance of failure. • Maintenance on fixed or duty basis • Opportunity Maintenance • Design out maintenance • Management Policy

8. Experience has shown that in a vast majority of cases, above time based maintenance is UNECONOMICAL. • Instead of the reducing failure rate of the machine by replacing wear parts regularly, the opposite often happens. • Reliability of newly serviced machine is reduced temporarily by the interference.

9. As the actual failure pattern for each individual machine cannot be predicted, an individual approach is therefore needed. • Here role of ON-CONDITION maintenance comes

10. On - Condition Maintenance • Each machine is considered individually by making fixed interval condition measurement to obtain a quantitative value of the ‘health’ of the machine. • In this way servicing is only allowed when measurements show it is necessary. • Basis is that most mechanical components give some warning of their impending failure.

11. Predictive Maintenance • Predictive maintenance technique use sensing instruments to determine health in much the same way a doctor uses medical instruments to determine human health • Instead of stethoscope, blood pressure , X-rays , ECG etc, Predictive maintenance use technologies like Thermography , vibration analysis , oil analysis , ultrasonic measurements to gain early warning in order to plan corrective action.

12. Why condition based diagnostic techniques for predictive maintenance preferred ? • Only 11-17% of failure are time or age related. • On average 83 – 89 % of failure are random.

14. Today’s Maintenance is too Costly • 65% of maintenance performed is corrective • 30 % of maintenance is preventive of which • 60% is unnecessary • 5% is predictive

15. Use of condition based Predictive maintenance has dramatically reduces non- value added maintenance by eliminating the need of unnecessarily shutdown of the equipment for maintenance checks

16. Principle of Condition Monitoring

17. Some techniques of Condition based Predictive Maintenance • Thermography: infrared imaging to detect abnormal temperature or hot spots. • Vibration monitoring: accelerometer instruments can be used to detect abnormal or high vibration particularly in bearings. • Oil Analysis: Analysis of oil can detect the deterioration or breaking down of an internal equipment part. • Ultrasonic measurement: Use of ultrasonic technologies to detect leaks or blockages on utility system.

18. Vibration Monitoring • Best known technique for rotating machines such as pumps, air compressor steam turbine etc. • All machines to have some level of small vibration • Increase in the level of vibration is the indication of some mechanical fault in machine.

19. Vibration analysis uses accelerometer instruments to detect these vibration movements . • Results can be plotted (magnitude v/s frequency) using a mathematical representation called Fast Fourier's Transform (FFT). Which highlight the level of vibration and identifies which frequencies they are present in.

20. Relation Between Vibration and Mechanical Component Typical vibration analysis FFT plot (magnitude vs. frequency)

22. Vibration analysis plot contain multiple fault frequencies • Analyst needs a detailed knowledge of the operating characteristics of the equipment (such as number of fan blades , RPMs, pulley ratios, bearing types etc)

23. Following type of problems can be determined using vibration analysis • Unbalance of rotary components • Mechanical looseness • Misalignment of drive system , shafts etc. • Belt deflection • Bearing deterioration and gear wear

24. Machine Condition and Vibration Spectrum Cited from Technical Associate Co. USA

25. Machine Condition and Vibration Spectrum Cited from Technical Associate Co. USA

26. Machine Condition and Vibration Spectrum Cited from Technical Associate Co. USA

27. Pressure Fluctuation Analysis of Pump

28. Pressure Fluctuation Analysis of Pump

29. Pressure Fluctuation Analysis of Pump

30. Thermal Imaging or Thermography • Thermography is a temperature profiling of surface or point based on IR Technique • It is based on the principle that every object units certain amount of IR energy and the intensity of this IR radiation is a function of temperature.

31. Thermal imaging is used primarily on electrical panels to identify loose connection but now it is use in other applications . • Checking for blockages in pipes. • Carrying out heat survey in plants. • Mill drive train misalignment • Leakages from steam traps. • Misaligned pumps.

32. What is Thermography? The term "Thermography" refers to the capturing of thermal patterns and data emitted by an object with the use of an infrared imaging and measurement camera. An image is then produced with the camera that can give you data that is otherwise unattainable.

33. Infrared Zoon Wavelength 8 to 14 μm

34. What is Infrared? Infrared light is not visible to the naked eye because infrared wavelengths are too high on the electromagnetic spectrum. The wave lengths are longer than those of visible light and shorter than those of radio waves. This part of the electromagnetic spectrum is what we perceive as heat or “heat radiation”. Infrared is mostly associated with “hot spots”, but did you know that ANYTHING above absolute zero emits infrared heat?

35. INFRARED CAMERA

36. Hot Connector Diagnostics

39. Thermal Image of Compressor

40. Use of Thermography in Maintenance • Monitoring of temperature and thermal patterns on • Pumps • Motors • Bearings • Pulleys • Fans • Drives • Conveyors etc while equipment is on line and running under full load.

41. Condition Monitoring Industrial pumps are known to work continuously for many hours. If a pump stops working or starts to wear, this can cost a factory much needed time. Using an IR camera to monitor the temperature of these type pumps, a maintenance worker can spot troubled pumps BEFORE the failure and address with little or no down time - saving you time and money.

43. Thermal imge of Plastic moulding showing uneven cooling

44. Thermal Image of Ball Bearing

45. Advantage of Thermography • It is non destructive and non contact type technique • It gives fast, reliable and accurate measurements. • Capable of catching moving targets in real time • Large surface area can be scanned • Measurement in areas inaccessible for hazardous for other methods • Disadvantages • Duality cameras are expensive having + 2 or worsen accuracy • Ability to only measure surface areas. Unable to detect the inside temperature

46. Leakage from a steam trap Application of Thermography to Paper Industry Steam Traps

47. Liquid Storage Tank Determination of liquid level

48. Pulley System Hot drive belts

49. Web Process In this web process, you can easily see the non-uniformity of the sheet along the right side