Silo Hopper Cleaning

Primasonics® Acoustic Cleaners have been of tremendous benefit in both preventing material hang-up and ensuring maximum, continuous material flow in silos and hoppers. The two main problem areas within hoppers and silos are:-

- Ratholing - where the material builds up on the sidewalls causing severely reduced "funnel flow", which also restricts the silo being used to its full storage capacity.
- Bridging - where the material bridges over the outlet area either severely restricting flow or stopping it completely.

Irrespective as to whether the bulk storage facility is around a few hundred lbs or over 30,000 tons capacity Primasonics® Audiosonic Acoustic Cleaners have eliminated both of these problems. In brief, dry material processing and storage companies not just in America but indeed in over forty countries worldwide, all have benefited from the employment of these acoustic cleaners within their silo and hoppers.

Typical examples range from small 20 tons capacity internal pre-packing hoppers right up to 30,000 tonne capacity cement silos. Where the problem is ratholing with the material building up on the sidewalls, a low frequency, larger Primasonics® Acoustic Cleaner is mounted on top of each silo to dislodge and thereafter, eliminate the build up. These units can be located at any position on top of the silo, as sound waves travel at over 1130 feet/344 metres per second and in a 360° radius. Generally speaking they are mounted on top of an existing inspection hatch, thus installation is simple and inexpensive as the examples below show. It is important to note and understand several main advantages that Primasonics® Acoustic Cleaners have over alternative methods, which have been employed to try and aid material flow. 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 vibration and stress weaknesses within the vessel or structure to which they are attached. The vibration resonances first 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% efficiency.

Air cannons/blasters seek to effect 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 finds a single air cannon in effective operation. This is totally the opposite with Primasonics® Acoustic Cleaners but then we approach the problem with a totally different philosophy - by preventing the build up from occurring in the first place.

So in simple terms how do Primasonics® Acoustic Cleaners Work?

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 periodical intervals.

Primasonics® Audiosonic Acoustic Cleaners are aiding material flow from hoppers and silos in such diverse industries as Cement, Gypsum, Flour, MDF Wood Products, Ceramics, Chemicals, Petrochemicals and Power Plant. They are also employed in a range of ancillary plant such as filters, cyclones, fans, ductwork and steam/power generation plants.

The Primasonics® Acoustic Cleaners are available with the bell sections manufactured from spun 316 grade stainless steel (PAS Range) or with the bell sections manufactured from Pre-woven glass fibre membrane which is resin transfer moulded (GRP Range).