How On Earth Do Simple Sound Waves Debond
Dry Material And Make It Flow?
There are lots of published technical papers, including many by our technical guys on how sound wave are a fantastic success in both preventing particulate (ash, for example) from building up on surfaces and also to prevent dry material (such as cement powder) from blocking by always keeping it moving. I just thought that I would cut through all the technical jargon (as best I can) and try and explain in simple terms why Primasonics® Acoustic Cleaner's sound waves are so successful at preventing material build up within a host of industries and applications.
The first startling fact is that our ears do not actually hear sound! Let me ask you - when you have been flying, or swimming underwater or even riding in an elevator - do your ears go 'pop'?. This occurs because our ears are a very sensitive pressure detection mechanism and can detect even minute changes in pressure.
This ear 'popping' problem we share with thousand of other people is caused by a pocket of air inside the middle ear - the space behind the eardrum.
The air in the middle ear is constantly being absorbed by the membranes that line the cavity, so the internal pressure can easily drop. Fortunately air is frequently resupplied to the middle ear during the process of swallowing.
Usually when you swallow, a small bubble of air passes from your throat or back of your nose, through a narrow tube known as the Eustachian tube, into your middle ear. You usually then hear a tiny click or popping sound which tells us that equal air pressure has been restored on each side of the eardrum.
So now you know that you ear responds to changes in pressure and that we simply call these many pressure variances as 'sound'.
Sound therefore may be described as a series of very rapid 'pressure fluctuations' and it is these very rapid fluctuations which actually cause dry material to debond.
Sound waves travel at a speed of around 244m (1128 ft) per second through air and at up to an amazing 5000 m (16,400 ft) per second through solids. Compare this to a bullet fired from a gun which travels at a speed of around 1,500 miles per hour which equated to 670 m (2,200 ft) per second.
The diagram to the right shows a typical jumble of different frequencies which we 'hear' and can be a combination of the high pitched voice of a child's laughter mixed with the rumble of a passing large road wagon i.e. high and low frequencies together. Our job is to design a range of Audiosonic™ Acoustic Cleaners which can produce as pure a frequency as we have designed it to do.
We use a range of different frequencies from 420 Hz (spelt Hertz) down to 60 Hz. The diagram on the right above shows two examples of such pure frequencies with the higher (and shorter) wavelength on top (say 420 Hz) and the lower (and longer) wavelength on the bottom (say 60 Hz).
The higher & shorter the wavelength, the less distance it can travel and of course, the lower & longer the wavelength the greater distance it can travel. We use this phenomenon in both the design and operation of our Primasonics® Audiosonic™ Acoustic Cleaner Range. Look at the typical wavelength and imagine that every time a peak goes above the horizontal line it has a pushing (+) action and that every time a peak goes below the horizontal line it has a pulling (-) action. Therefore, for example with a 350Hz Acoustic Cleaner these strong push - pull actions occur 350 times every second. You can now see how then these sound waves can effectively make dry material debond not only one particle from another but also from the surface (silo wall or steam pipe) to which they were initially attached. Also because the sound wave spectrum of our Audiosonic™ Acoustic Cleaners lies within the range of 420 Hz down to 60 Hz they do not cause any damage to the structure itself such as a concrete silo or steel fan.
