Ultrasonic Inspection Systems

Ultrasonic inspection is the single most versatile technology for maintenance and reliability of your vital assets.  A multitude of powerful applications coupled with an attractive initial investment cost makes our ultrasonic inspection systems the number one choice for maintenance departments around the globe.

Our Ultrasonic Inspection Equipment utilizes "Ultrawave" technology that represents 20 years of R&D of ultrasound detection. SDT introduced the first digital ultrasonic detector in 1985. Our competitors released their first digital technology in 1999.  STD had a 15 years head start on the competition.  Our competition are only now going to realize all the errors and complications that we ratified since the first release.

What makes the Ultrawave technology special?

By definition, ultrasound refers to noise that is above the range of human hearing (beyond 20 kHz). Many cheaper units on the marketplace are by definition ultrasonic detectors. But by function they are simply noise amplifiers. It is relatively easy to build electronics that can detect ultrasound.  But it requires considerable expertise and cost to develop electronics that detect ONLY ultrasound in a specified bandwidth.   Ultrwave technology takes advantage of expertise gathered over 20 years.

What frequency is best for detecting air leaks in areas with high ambient noise?

40kHz.  Why?  Air leaks produce wide-band sounds and ultrasounds.  Normally a leak sound gets more energy the higher it goes into the frequency band.  But the higher we go in the frequency band the less conductive air is for ultrasound.  If we plot air conductivity (attenuation) and frequency energy on a graph we will see the two lines meeting at around 40 kHz.  By choosing this frequency and filtering out all others the Ultrawave takes advantage of maximum detection distance from the source and minimum disruption from parasite noise.  This combination makes our detector the most effective unit on the market for high noise areas.

 Applications

Compressed air leaks are the most expensive utility waste in manufacturing. Turbulence from leaks creates white noise with a strong ultrasonic component. Scan an area with the Ultra-wave and hear the turbulent rushing sound through the headphones. Ultra-wave pinpoints all pressurized gas and vacuum leaks regardless of ambient background noise. Finding leaks can save hundreds of thousands of dollars.

Read "The Trouble with Air Leaks" written by Liane Harris

Roller bearings produce ultrasonic friction as the internal rolling elements turn against the raceway.  Likewise, the friction absorbing properties of grease means a well-lubricated bearing produces less friction than a bearing that lacks lubrication. True digital RMS readings from the SDT 170 provide accurate and reliable advanced warning of impending failures to rotating equipment.

AVM™ - Acoustic Vibration Monitoring trends high frequency bearing energy to determine proper lubrication intervals and predict when the bearing is entering its FIRST stages of wear.  Over lubricating bearings can damage seals, build pressure on the bearing, and cause premature failures. Over greasing an electric motor can push lubricant into the windings causing shorts and more severe damage. Under lubricating bearings negatively affects the lifespan of rotating machinery also. So how can you get it just right??  The SDT 170’s advanced digital detection techniques opens up communications between bearing and lubricator. Let the bearing tell you how much grease is enough.

Rising energy costs make steam an expensive utility… too expensive to waste. A typical failure rate is 30-40% of a facility's steam trap population. Failed traps also contribute to contaminated, poor quality steam and dangerous water hammer.  Ultrasonic testing gives the inspector an "inside view" of the trap. The SDT 170 translates high frequency ultrasonic noise to audible frequencies localized to the source of contact. The inspector will not be disturbed from ambient parasite noise downstream.  Temperature measurements upstream and downstream of the trap can often provide alerts to failed traps. The SDT 170 M and 170 MD Steam Trap Inspector’s Kit includes a standard non-contact temperature measurement interface to further enhance trap inspections.

Internal blockage or leaks in valves can be discovered precisely while the system is on-line. Troubleshooting hydraulic circuits to find internal leakage is fast and easy with the Ultra-wave. With the Ultra-wave in "contact mode" take sample readings along the circuit. Technicians can clearly define the direction of flow, and more importantly, the source of trouble even in high noise areas. Internal leakage across seals on hydraulic rams produce microscopic bubbles of oil which in turn "pop" as they pass from pressure side to non-pressure side. These small explosions produce ultrasound energy which is easily detected in the Ultra-wave’s headset. Tune the frequency of the detector to eliminate competing ultrasounds.

Cavitation is usually the result of a pump being asked to do something beyond its specification. Small cavities of air develop behind the vanes. These pockets have a destructive effect on the pump’s internal components, including pitting and scarring the surface of the vanes.  With the Ultra-wave in contact mode, isolate the pump vanes and listen for small air pocket explosions. Comparing similar pumps will help the uninitiated, but with some experience an operator will quickly be able to detect pump Cavitation.

Use the Ultra-wave to scan for external pressure or vacuum leaks in boilers, heat exchangers, and condensers. Listen for the same rushing sound that is associated with compressed gas and vacuum leaks. All pipe connections, flanges, seals, and access doors should be inspected as part of regular PM’s.  Tube leaks in condensers and heat exchangers can be inspected using either the pressure method, the vacuum method, or the bisonic transmitter method. Choose the method that suits your application and see your inspection time decrease dramatically.

Reciprocating compressor valves open and close to allow internal combustion motors to "breath".  When these valves become dirty, or carbonized, their efficiency is reduced. A valve that is seating properly should be quiet while defective valves are characterized by the familiar rushing or turbulent sound of a leak. Signals from valves can be analyzed with SDT’s Ultranalysis™ software. Real-time waveform analysis will reveal heavy jagged peaks representative of valve leaks. Trend these changes to PC with the SDT 170 MD and Data Manager™ software.

Electrical Inspections

Corona discharge, arcing, tracking, damaged line bushings, and other potentially dangerous and wasteful conditions in high voltage systems produce ultrasound as a warning of future failure.  By itself, or as a compliment to Infrared Imaging, Ultrasonic Detection has become the technology of choice for electrical inspections of:

• Transmission & Distribution Lines

• Substation Inspections

• Switch Gear

• Transformers

• Partial Discharge

• Arcing, Tracking, and Corona

• Radio/TV Interference

Electrical faults emit ultrasound at the site of the problem. Scan an area in the same way one would for leaks. Characteristic frying, popping, buzzing, and humming sounds can be associated with different faults. Build a library of faults by recording sound waves and sharing them on your company intranet.

Tightness Integrity - Wind Noise & Water Leaks

Quality control applications were developed for the transportation sector to improve the tightness of vehicles. The method consists of flooding the interior of a volume with microscopic ultrasound waves. Due to their properties these waves can penetrate small holes. Using the SDT 170 detector on the outside of the volume inspectors can quickly pinpoint the source of defects that could become potential sites of water leaks or wind noise.

Current sector uses:

Aerospace Industry:	Integrity of Aircraft and Helicopters
Marine Industry:	Hatch Covers of Cargo Ships
Automotive Industry:	Wind and Water Leaks on any Vehicle
Trucking Industry:	Trucks, Buses, Trains
Building Industry:	Integrity of Building Envelopes
Nuclear Reactors:	Containment Wall Integrity
Military Equipment:	Submarines, Aircraft, Space Vehicles

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