UE Systems Ultrasonic Detection Equipment

Ultrasonic Compressor Inspection

DESCRIPTION
Compressors are the heart of any compressed gas system. Routine inspection and maintenance can prevent unplanned downtime. Although any type of compressor can be inspected ultrasonically, the most common application center around larger reciprocating types. Specifically, valve function in these compressors is critical. Minor valve leaks can rapidly lead to large leaks which can effect production and impact on plant safety.

How Ultrasonic Compressor Inspection Works
As with any mechanical movement, there is a "normal" operation and a "deviation". In the case of valves, normal function is the typical open/close movement. Ultrasonically this will be observed a s a rhythmic movement. When valve movement changes due to leakage or sticking, the sound pattern changes. Each condition has ultrasonic components that can be sensed and monitored by the Ultraprobe. Due to the short wave, high frequency nature of ultrasound, the sounds produced by a compressor valve can be isolated, which provides a clear test result.

Detection Method
There are two procedures for ultrasonic valve inspection, "direct" and "accessorized".

For the "direct" method touch the valve with the contact probe and reduce the sensitivity until it is possible to obtain a meter swing around mid-line and hear the valve open/close movement. If more clarity is desired, try tuning the frequency to around 25 kHz. When testing, be sure to compare similar valves to each other (i.e. intake to intake, exhaust to exhaust) and under the same conditions (i.e. idling vs. working). For additional localization, use the scanning module with rubber focusing probe.

The "accessorized" method incorporates additional apparatus to provide a more detailed analysis. A Magnetic Mount (UE-MMP-2) with an Interconnection Cable (UE-EXC-2000) is used in place of the standard contact probe. The magnetic bond eliminates the possibility of excessive mechanical vibration from influencing the meter readings. In addition to this arrangement, more detailed analysis may be obtained by interfacing the demodulated signal of the Ultraprobe with an oscilloscope or engine analyzer or Vibration Data Collector.