COBOURG, Ontario - Ultrasound inspection is a mainstream technology used by predictive maintenance and reliability professionals to gather important information about the health of their equipment including mining fleets. Recently one mining company discovered that ultrasound is a fast and simple way to pinpoint invisible leaks on air intake systems and turbochargers.
The company verified dust contamination in the engine oil by lab analysis of the oil. It was presumed that the dust ingress was at the turbocharger, but after eight hours of visual inspections the leak sources could not be determined. One smart inspector decided to use his SDT270 ultrasound detector to find the leaks. Within 10 minutes he identified three hidden leaks.
The inspection is now mandated on every asset in the mobile fleet. Within the first six months, the mining company’s accounting office reported an $8 million savings from premature engine failures and lost production. The company (and inspector) has since won an industry award for this smart idea.
Using the SDT270 to find the leaks is easy. The employee placed a 200-mW ultrasonic transmitter placed inside the inner air filter. Both air filters were replaced and the breather system was resealed.
The entire breather system from the filters to the engine was probed with the SDT270. All locations along the breather piping and joints displayed ultrasound readings from 20-24 dBµV. One location, inside a clamp on the right hand side of the loader gave readings of 34-38 dBµV, an increase of 14 dB (five times louder at the leak site). This indicated thinning metal and pinhole leaks.
Another leak was found between two pipes. The pipes were supposed to have one inch separation but were touching and rubbing together. The leaks were heard ultrasonically without pulling the pipes apart. Upon separation two significant holes were identified.
The leaks were found quickly, the repairs were done in the weld shop with relative ease, and the validity of the repair was further checked with the ultrasound detector. The final confirmation came with the next oil sample which was free of aluminum, nickel and silica.
For more information contact Allan Rienstra at SDT Ultrasound Solutions, allan@SDTHearMore.com or 905-337-1313 and ask for a copy of his paper, Mobile Fleet. Or go directly to SDTHearMore.com/pages/cmj/dusting-in-diesel-engines.html.
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