By sensing subtle ultrasonic changes in equipment, the Ultraprobe 2000 by UE Systems Inc., locates leakage in heat exchangers, pneumatic systems and steam traps.  Moreover, it will diagnose problems in motors, including incipient bearing failures, as well as detect cavitation in pumps.  The Ultraprobe is a portable instrument that electronically converts a narrow band of ultrasound in the audible range, which is then heard in headphones and gauged on an analog meter.  Interchangeable modules allow for inspection of equipment in either a contact or scanning mode.  The former is most often used to diagnose mechanical problems, as well as steam trap and valve leakage, while the latter is generally used to detect pressure and vacuum leaks.  System flexibility is enhanced with features such as frequency tuning and meter mode selection.   Frequency tuning enables users to minimize the effects of competing ultrasonic signals while tuning into problem sounds in operating equipment.  Meter mode selection adjusts the meter from a real-time response for leak detection to an averaging response for mechanical analysis.

Four Ways to Test
There are four basic methods for testing a heat exchanger, two online, scan and contact, and two off-line, pressure and tone.  While on-line, a scan of the exchanger will locate leakage through fittings and headers.  The contact probe is used to touch the shell wall in order to detect changes in the normal turbulence which will indicate tube leakage. Off-line testing is performed by pressurizing the shell side and scanning the tube sheet for a tell-tale white noise.  Tubes and tube rolls suspected of leaking may be tested with the aid of an ultrasonic transmitter called a Tone Generator.  By injecting a strong ultrasonic signal into the shell of a heat exchanger, the signal will penetrate leaking tubes and vibrate thin-walled tubes.  Leaks through tube rolls will also allow the generated ultrasound to penetrate.  A scan of the tube sheet for sonic penetration with the Ultraprobe will pinpoint the exact source of leakage.

Bad Bearings Beware
Bearing failure is one of the most common causes of motor breakdown. The National Aeronautics and Space Administration has reported that ultrasonic monitoring of bearings is perhaps the most effective method of detecting incipient bearing failure.  What's more, ultrasonic monitoring will detect a problem long before it will be detected by vibration or heat.  Most steam trap manufacturers recommend ultrasonic testing of traps because it is a positive test.  A user will observe exact trap function without interference from extraneous pipe sounds.  Pressure and vacuum leaks produce strong ultrasonic components.  Because ultrasound is a short wave signal, it is loudest at the peak site, which allows for ease of detection in typical plant environments.