Ultrasound Technology and Compressed Air Audits Ultrasound Technology and Compressed Air Audits

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

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)

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

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

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

TYPICAL ULTRASONIC TRANSLATOR

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 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 They are heard through headphones And observed as intensity increments on a meter or display panel. And observed as intensity increments on a meter or display panel.

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

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. Use the heterodyned output: the headphone jack and connect to a suitable recording device. The captured sound can be analyzed using Spectral Analysis Software. The captured sound can be analyzed using Spectral Analysis Software.

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

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

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

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

How An Air Leak Generates Ultrasound

Relating Sound Levels to CFM

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

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

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

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

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

Test, Listen, Record

Data Log Data log all readings Data log all readings Take Photographs of all leaks Take Photographs of all leaks

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

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

AIR LEAKS COST !!!!!! LEAK DIAAIR-LOSSLOSS/DAY LOSS/DAY LOSS/YR. CFMCU.FT/DAY $ $ / / / , / , / , / , / , / , / , , / , , / , , / , , / , , / , , / , , / , , / , , / , , / , , / , , NOTE: Based on 100 PSI, $0.25 /mcf, 8760 hours / year

Questions on Leak Detection?

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

ELECTRIC INSPECTION CORONA CORONA TRACKING TRACKING ARCING ARCING

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!!

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

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