Hoppers & Silos
inspection hatch, thus installation is simple and inexpensive. A typical example is shown in Photograph 1.
Moving on to silo and hopper discharge, in such applications one of the smaller Primasonics Audiosonic Acoustic Cleaners model such as the PAS-350 or PAS-420 with higher frequencies is employed. The higher the frequency the shorter the wavelength and so all the acoustic power created by the Wave Generator is concentrated over a much shorter range – say between 1 and 5 m. Therefore a higher frequency Primasonics Audiosonic Acoustic Cleaner mounted just above the discharge will prevent material bridging and ensure even maximum material fl ow. A typical example is shown in Photograph 2.
vibration and stress weaknesses within the vessel or structure to which they are attached. The vibration resonances fi rst have to pass through the vessel wall before reaching the material. With the Acoustic Cleaner, the higher frequencies are directly absorbed into material giving 100% effi ciency.
can replace multi air cannons; however we then approach the problem with a totally different philosophy - by preventing the build up from occurring in the fi rst place.
HOW DO PRIMASONICS ACOUSTIC CLEANERS WORK?
Photograph 1:
One of two PAS 75 on silo CIM, Haiti
Acoustic cleaners are extremely simple in their operation, requiring only normal plant compressed air for their initial energy source. Compressed air enters the Wave Generator and forces the only moving part, the ultra high-grade titanium diaphragm to oscillate very rapidly within its specially designed housing. These rapid oscillations create the base tone
and the various different bell sections convert,
amplify and distribute this base tone into a range of different key fundamental frequencies. Primasonics have selected seven such key fundamental frequencies for their Audiosonic Acoustic Cleaner range from 60 Hz to 420 Hz.
The acoustic cleaners only require activating for a few seconds at
Photograph 3: Prima Range from Primasonics
periodical intervals. The Prima Range of Acoustic Cleaners is shown in Photograph 3.
Primasonics Audiosonic
Photograph 2:
It is important to note and understand several main advantages that Acoustic Cleaners have over alternative methods, which may have been tried in the past to try and aid material fl ow. Primasonics Acoustic Cleaners operate at frequencies very much higher than the resonance frequency of steel, ceramic lining, concrete etc. Therefore Primasonics Acoustic Cleaners are guaranteed not to cause vibrational damage to any vessel or structure. This is quite unlike vibrators, which by their very nature and method of installation, cause
22 March 2014 Solids and Bulk Handling
Air cannons/ blasters seek to affect a very
localised cure for a blockage problem, which has already occurred. In many cases the air cannon simply “blows” a localised hole through the blockage, necessitating the installation of many air cannons within the general problem area. It is generally true to say that one very rarely fi nds a single air cannon in effective operation. This is totally the opposite with Primasonics Acoustic Cleaners where a single Acoustic Cleaner
www.solidsandbulk.co.uk Acoustic Cleaners are
aiding material fl ow from hoppers and silos in such diverse industries as cement, gypsum, fl our, MDF wood products, ceramics, chemicals, carbon black, petrochemicals and power plant. They are also employed in a range of ancillary plant such as fi lters, cyclones, fans, ductwork, SCRs. ESPs and steam/power generation plants. n For more information visit:
www.primasonics.com and
www.quattrosonics.com
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