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ADASH Ltd.
Ultrasound
Introduction
We would like to explain a few terms in the beginning of this chapter.
Higher frequency energy above 20kHz is best detected with an ultrasonic sensor. Most useful information is
found between 30 and 50kHz. The Adash ultrasonic module enables monitoring ultrasonic energy.
Ultrasound utilizes a solid, liquid or gas to transmit (will not exist in a vacuum), and is a very directional and
short waveform. It has several things in common with the vibration, for instance the ability to detect the
ultrasound energy requires the sensor to be focused in the direction of the waveforms.
Field applications for airborne ultrasound detection:
- Consider the wave energy is easily reflected and attenuated.
- When looking to detect airborne ultrasound energy a rule of half distance twice amplitude is a good thing
to consider, this is called the "inverse rule".
- Remember airborne ultrasound is easily reflected, when detecting a leak, you should turn in the other
direction to determine if the sound is coming from behind you.
- Use shields such as cardboard or to isolate the potential defect from other sources.
For airborne ultrasound the instrument microphone attachment will detect:
- Air leaks
- Vacuum leaks
- Electrical Arcing
- Electrical Corona
- Tightness testing where a signal generator is located within a sealed unit, then by scanning the sealed
areas from the outside leaks can be detected.
The probe attachment that enables direct transmission ultrasound will detect:
- Early signs of poor lubrication in anti-friction roller bearings
- Impacting noise from defects in roller bearings including bearings with shaft speeds under 100 rpm.
- Steam trap leakage and failures
- Gearbox defects
- Valve leakage
- Actuator malfunctions
Sensor setting
The ultrasound measurement is available only on AC CH1. You need the ultrasound microphone for that. When
you run the module, then the sensor is changed automatically to Pascal sensor.
Use the Sensors / AC1 to change the sensitivity if needed. The new setting is saved and used in next run.
The original sensor is set, when you leave the module.
Settings
You can set the range of measurement. Use Menu / Ultrasound Settings. Enter required range.
For further technical and contact information visit www.adash.eu, email: info@adash.cz
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Adash 4400 – VA4Pro
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