Versatility of Ultrasound

Mechanical Wear

The theory behind ultrasonic detection is logical.  All plant machinery produces sound patterns – both sonic and ultrasonic.  Characteristics of those patterns change relative to the health of the machine.  Subtle changes in the ultrasonic range indicate early wear signs, changes in lubrication, and structural degradation of mechanical components (bearings, couplings, gears, valves, etc…).  Ultrasonic detection has proven useful for determining the onset of incipient bearing failure before conventional methods like vibration, temperature, or wear particle analysis.  Recent evolutions in ultrasound detection include dynamic memory capacity, digital data processing, the use of True RMS technology for enhanced repeatability, and two way data transfer between instrument and PC.

Leak Detection

Compressed air leaks create noise that has both an audible and ultrasonic component.  The audible component is not useful for leak detection due to its non-directional properties and ambient plant noise that can exceed 130 decibels.  However the ultrasonic component of a leak is very useful for leak detection because of its directional properties and the ability of a quality detector to filter out ambient plant noise.  Rising energy costs make compressed air single most expensive utility in most manufacturing facilities.  Combined with the high rate of leakage found in most plants (average leak rate of 40 - 50% was common in 100 plants surveyed), cost justification is often based solely on implementation of a compressed air leak program.

Steam Leaks

Like air leaks, it is an alarming reality that maintenance personnel routinely ignore steam leaks.  Steam leaks can exist anywhere in a system and finding became much easier with ultrasonic detection.  Steam passing through an orifice generates ultrasonic turbulence that is picked up with the contact probe.  Place the probe upstream and downstream of the trap and compare ultrasonic readings.  Louder levels downstream indicate the trap or valve is open.  Lower level indicate its closed. 

Determining faulty traps relies on the operator knowledge of the trap's internal function.  Using a comparative method between several similar traps will confirm any suspicions of failure.  Ultrasonic Detection can also be used to check solenoids, relief valves, check valves, control valves, needle valves, and air actuated cylinders.