Ultrasound Technology and Compressed Air Audits

1. Ultrasound Technology and Compressed Air Audits

2. Brief Overview of Ultrasound • Ultrasonic frequencies are high frequency signals that are above range of human hearing. • Human hearing range is 20 Hz to 20 kHz • Ultrasound instruments sense 20 kHz to 100 kHz • High frequencies have characteristics that work differently than low frequencies in the audible range.

3. Low Frequency Sound Waves Range in Size from 3/4 of an inch to 56 feet (assuming the average hearing is 16.5 kHz) High Frequency (Ultrasound) Sound Waves Range In Size from 1/8 of an inch to 5/8 of an inch (assuming ultrasound range from 20 kHz-100kHz)

4. Ultrasonic Characteristics Characteristics of short wave sounds: • They are directional/detectable • They are localized to the source of emission • They will reflect and not penetrate solid objects making them easy to block/shield • They can be sensed in loud, noisy environments • Subtle changes can be noted to provide early warning of failure

5. SOUND PENETRATION • Low Frequency Wave • Vibrate Solid Surfaces • Large Objects Appear Transparent • High Frequency Wave • Short • Weak • Can not Penetrate Solid Objects MPEG SUPERSONIC FLYBY OF AN F14 SHOWING THE SOUND WAVE WITH A VAPOR CLOUD

6. How Do We Detect Ultrasound? Using a digital ultrasonic translator which provides: • Display Screens with test data including Decibel and Frequency read outs. • Software for data management • Sound recording ability and sound analysis software

7. TYPICAL ULTRASONIC TRANSLATOR

8. How Do these Ultrasonic Translators Work? • The Ultrasound is detected and these sounds are then translated down into lower frequencies within the range of human hearing • They are heard through headphones • And observed as intensity increments on a meter or display panel.

9. Interchangeable Modules • Leaks Are Detected By: • Scanning Module • Stethoscope Module • Tone method • Specialized Methods May Be Considered: • Long Range Module Non Accessible Leaks • Liquid Leak Amplifier Laminar or “TINY” Leaks

10. Sound Recording The translated ultrasound samples can be recorded for further analysis. • Use the heterodyned output: the headphone jack and connect to a suitable recording device. • The captured sound can be analyzed using Spectral Analysis Software.

11. Where Do Air Leaks Occur? Mechanical Seals Threaded Fittings Sealant Problems Gaskets Corrosion/Erosion Structure Penetrations

12. Considerations in Leak Detection • Turbulence • Orifice Shape • Fluid Characteristics: Viscosity & Molecular Wt. • Pressure Differentials • Distance From Leak • Competing Ultrasounds • Accessibility to Leak • Atmospheric Conditions

13. Turbulence Turbulent Leaks Emit Ultrasound Based on Their Shape, Pressure At the Leak, and other Factors

14. ORIFICE Shape of the Orifice is the Determining Factor in How Much Detectable Ultrasound is Present

15. How An Air Leak Generates Ultrasound

16. Relating Sound Levels to CFM

17. Conducting a Compressed Air Survey • Gather Data • Compressor Info • PSIG Operating data • Hours of Operation • Begin Survey at Compressor • Follow Air Lines to all Pieces of Equipment • Record dB Readings of Leaks • Take Photographs of Leaks

18. How do we do this? • Create a route • Set up the instrument • Gather relevant data • Test, listen, record • Data log • Generate Report

19. Create A Route Plan carefully • With plant personnel, determine the optimal route for inspection and ease of follow up for repair. • Create a method of equipment identification (if none exists)

20. Set Up Instrument • Verify the sensitivity: it should be working the same from one inspection to the next. • What frequency to use: record this for consistency • What test module to use?

21. Gather Relevant Data • Date and Time • Compressor Data • Operating Pressures • Hours Operation • Any Special or Hazardous Conditions

22. Test, Listen, Record

23. Data Log • Data log all readings • Take Photographs of all leaks

24. Generate a Cost Report • Place Recorded dB Readings in Analysis Software • Generate Report of dB Sound Level of Each Leak Converted to CFM with Associated kW Usage and Annual Cost of Leak

25. Place Pictures with Report • Place Photos of Each Leak Location that Numerically Matches the Cost Report

26. AIR LEAKS COST !!!!!! LEAK DIA AIR-LOSS LOSS/DAY LOSS/DAY LOSS/YR. CFM CU.FT/DAY $ $ --------------------------------------------------------------------------------------------------- 1/64 .40 576 0.14 50.40 1/32 1.60 2,304 0.58 211.00 3/64 3.66 5,270 1.32 481.00 1/16 6.45 9,288 2.32 846.00 3/32 14.50 20,880 5.22 1,904.00 1/8 25.80 37,152 9.29 3,389.00 3/16 58.30 83,952 21.00 7,661.00 1/4 103.00 148,320 37.08 13,526.00 5/16 162.00 233,280 58.32 21,275.00 3/8 234.00 336,960 84.24 30,731.00 --------------------------------------------------------------------------------------- NOTE: Based on 100 PSI, $0.25 /mcf, 8760 hours / year

27. Questions on Leak Detection?

28. Other Uses for Ultrasonic Inspection • Electrical • Corona • Tracking • Arcing • Detecting Interference • Lubrication • Motor Testing • Complements Infrared

29. ELECTRIC INSPECTION CORONA TRACKING ARCING

30. WHAT ULTRASOUND FOUND AND INFRARED MISSED Here We See A 138KV Line In A Substation That Had a Wire That Was Corroded Due To Corona. It Broke Loose And “Welded” Itself Back To Another Point Due To The High Current Load. This Was NOT Detected By The System Monitors!!

31. OVER LUBRICATION • AN EXAMPLE OF:OVER LUBRICATION BARE WIRE Bad Being Lubricated Good

32. Conclusion • ULTRASOUND: • Versatile • Simple to use • Provides definitive data of air leaks • Supports other technologies • QUESTIONS??? THANK YOU