Acoustic Cleaning is the use of high energy – low frequency sound waves which eliminate particulate build up and maintain material flow throughout a wide range of “dry processing” industries and applications.
Sound may be best described as the rapid passage of pressure fluctuations through bonded material by means of a vibrating source and transmission medium.
We have selected a range of key fundamental frequencies between 60 and 420 Hz for a very particular reason. At the 420 Hz frequency the wavelengths are much shorter than at the 60 Hz frequency level. Therefore where high intensity, short distance material debonding is required (for example at the discharge of a silo) we would employ a suitable higher frequency Audiosonic™ Acoustic Cleaner. The opposite is true for say large silos; here to prevent material build up of a sidewall a suitable low frequency Audiosonic™ Acoustic Cleaner is employed to provide long-distance debonding power.
Particles with different masses and clusters of particles are all hit by the alternating sound waves as the particles have different masses they travel slightly different distances, when this is repeated between 60 and 420 times per second the particles start travelling out of phase with each other and break apart.
The sounding is created when normal plant compressed air enters the Wave Generator this forces a diaphragm which acts a little like a reed to allow pulses of air into the horn section. The frequency of the sound is then dependant on the size and shape of the horn section.
Very much so, imagine a church bell and why it is shaped in the manner it is. This is for two reasons, firstly to provide as pure a tone (or fundamental frequency) as possible and secondly to cover an effective range. Could you imagine a square, straight-sided bell sounding properly – no of course not and that is why all our bell sections are precision spun in this exponential round bell shape.
Vibrators by their very nature and location have to first pass all their vibrations through the wall of the vessel. This results firstly in severe loss of power and secondly the damaging transmission of vibration through the vessel which can result in metal fracture. With Audiosonic™ Acoustic Cleaners – 100% of the debonding power goes into the material without any risk of damage to any structure or material of construction.
Air Cannons employ a unidirectional “blast” of high-pressure air to try and remove blockages that have already built up. That is why you always see groups of Air Cannons on any part of an application. Audiosonic™ Acoustic Cleaners prevent the build up from occurring in the first place. Sound waves travel in a 360° radius at a speed of 344 metres per second, therefore a single Audiosonic™ Acoustic Cleaner can be much more effective.
Both are very important, the frequency provides the correct number of debonding pressure fluctuations and the dB provides the necessary energy to successfully complete the job.
Primasonics® Audiosonic™ Acoustic Cleaners are designed by tuning the wave generator and shape of the horn so that sound is reflected from solid surfaces rather than passing into them this helps in three ways, equipment is not vibrated and damaged, sound is increased inside the vessel where cleaning is required and as the sound is contained in the vessel this reduces noise nuisance.
The Audiosonic Acoustic Cleaners operate using normal plant compressed air provided three important factors exist.
- Compressed air piping up to the cleaner – 25 mm diameter
- Compressed air pressure – 4.8 – 6.2 bar/70 – 90 psi/ 480 – 620 kPa
- Compressed air volume* – 21.25 l/s 45 SCFM @ 5.5 bar/80psi
* – but remember the Audiosonic™ Acoustic Cleaner is only “sounded” for a few seconds over usually between every 3 – 30 minute period depending on the application.