APT Sound Testing - Telephone 01525 303905
Ultrasonic Testing

Ultrasonic Testing

What is Ultrasonic Testing?
Many electrical and mechanical problems produce sound and vibration at ultrasonic frequencies (greater than 20kHz). Unfortunately, these sounds are not audible by the human ear. These sounds can be detected by ultrasonic listening instruments. As a result these versatile instruments have been integrated into our Predictive Testing Service.

Ultrasonic testing is used in two ways in our Predictive Testing Service. First, it permits us to identify faults that cannot be detected by either infrared or vibration tests. Second, it permits an independent verification of problems that can be detected by the infrared or vibration tests.

What problems may be identified by ultrasonic testing?
Most mechanical faults will generate ultrasound. Such faults include bearing and gear defects as well as mechanical looseness. Ultrasonic testing generally provides earlier warning of these types of faults than vibration or infrared thermal tests.

Other mechanical faults that are found by ultrasonic testing include:

» Ultrasonic survey of high voltage power lines
Due to the larger distances involved ultrasonic surveys on high power voltage lines the sensitivity of the instrument is enhanced by using a parabolic signal concentrator ultrasonic testing is extremely valuable for inspections of high voltage electrical systems (above 2,000V). it is essential that these systems have properly functioning insulation systems. Failure of these systems can result in catastrophic faults. Deterioration of high voltage insulation produces an electrical leakage known as corona or partial discharge. This condition causes ionization of the surrounding air. The ionization process produces ultrasound which is easily picked up by our ultrasonic equipment.

» Ultrasonic survey for Electrical Inspections
One of the main uses for ultrasonic testing is on electrical switchgear, transformers; buss bars circuit breakers, relays, junction boxes, insulators, and other electrical gear. Arcing & corona discharge produce ultrasound at the site of emission. These electrical discharges can be located quickly by scanning an area with our Ultrasound equipment. The signal is heard as a buzzing sound in the headset. As with pressure or vacuum leak detection, the closer the instrument is to the discharge, the more intense the signal.

» Ultrasonic survey of Valves
Mechanical valve activity such as blockage or leakage can be accurately checked while the valve is on line. Properly seated valves are relatively quiet while leaking valves produce a turbulent flow as the fluid moves from the high pressure side through the leak to the low pressure side. Due to a wide sensitivity and ultrasonic frequency selection range, all types of valves even in noisy environments can be accurately tested for leaks.

» Ultrasonic survey of Valve Stems
Valve stems may be quickly tested for leaks to atmosphere even in noisy environments.

» Ultrasonic survey of Pressure/Vacuum Leaks
As gas such as air, oxygen, nitrogen passes through a leak or crack it generates a turbulent flow with detectable high frequency components. A leak can be heard through the headset as a rushing sound or noted on the display/meter. The closer the instrument is to the leak, the louder the rushing sound and the higher the reading.

» Ultrasonic survey of - Steam Trap Inspection
Major steam trap manufacturers have recommended ultra sound inspection of steam traps as one of the most reliable methods available. By converting the ultrasonic elements of a working steam trap into the audible range, ultrasound allows users to hear through headphones and see on a display/ meter the exact condition of a steam trap while it is on line. Blow-by, machine gunning, oversized traps or line blockages are all easily detected. Frequency tuning enhances the ability to discriminate between condensate and steam.

» Ultrasonic survey of Reciprocating Compressor Valve
Analysis has become so successful with ultrasonic testing that many engine analyser companies now offer instruments with an ultrasonic input port.

» Ultrasonic survey of Bearing Inspection/Monitoring
Bearing Inspection & Monitoring detects the earliest stage of bearing failure. Research has demonstrated that ultrasound bearing monitoring will locate potential bearing failure long before it is detected by traditional heat and vibration methods. Using ultrasound testing the user hears the sound quality of a bearing as well as monitor amplitude changes on the display/ meter. This provides the ability to trend, trouble shoot and confirm potential bearing problems. We can undertake this on wind turbines etc.

» Ultrasonic survey to Prevent over-lubrication
Over lubrication is one of the most common causes of bearing failure, by simply lubricating only until the meter reaches a specified level this lowers the chance of over lubrication.

» Ultrasonic survey of General Mechanical Inspections
Ultrasonic survey of General Mechanical Inspections of pumps, motors, compressors, gears & gear boxes: All types of operating equipment may be inspected with an works in a high frequency, short wave environment, problems such as cavitation in pumps, compressor valve leakage or missing gear teeth may be heard and isolated allowing for quick and accurate diagnosis.

» Ultrasonic survey to Heat Exchangers, Boilers & Condensers
In-leakage or pressure leakage can be readily located using ultrasound. Fittings, valves, flanges are all easily scanned for leakage. The high frequency, short wave nature of ultrasound allows operators to pinpoint the location of a leak in high noise environments. Condenser tubes and heat exchanger tubes may be tested for leakage through three methods: vacuum, pressure & ultratone.

» Ultrasonic survey for Heat Exchangers
A powerful high frequency transmitter floods the shell side of the heat exchanger with ultrasound. The generated sound will follow the leak path through the tube. A scan of the tube sheet will indicate the leaking tube.

We offer a nationwide service offering a single supplier for all of your regional offices and projects. If you require a thermal imaging survey please call us now on: 01525 303905 or email us at: info@airpressuretesting.net



APT Sound Testing Services
Head Office: Sayells Farm, 7 Harlington Road, Upper Sundon, Bedfordshire, LU3 3PE

APT Sound Testing Services