Vertical Wall Build Up

Vertical wall build up on the inner walls of silos and hoppers is the first step in issues such as Bridging or Ratholing. It can be a serious, recurring problem that will reduce the efficiency of the silo in the short and long term. It also means that the maximum capacity of the vessel can’t be utilized if vertical wall buildup is present.

Caused by friction on the inner walls of a silo, material buildup will restrict the content from flowing freely. As a result, the particles bind together to form blockages. This either severely restricts the silo’s funnel flow or stops it completely, which in turn causes increased stresses on the wall. To overcome the issue, the friction must be reduced.

Silo wall buildup is especially prone in adverse weather conditions. In hot summers or cold winters, the walls of metal silos can expand in the heat and contract at as the temperature drops. This phenomenon which can be repeated every day is called thermal ratcheting.

Flow disruption ultimately reduces the volume of fresh product that the silo can hold and may eventually make it unusable.

Different materials are stored in silo and hoppers and therefore different problems can occur. One example is when the interior surface of a hopper can become polished as a result of the wear from abrasive bulk solids.

As with any structure, silos and hoppers must be properly maintained if they are to have a long, useful and safe life. Regular preventative work of the roof vents, level probes, feeders, dischargers and gates should be carried out. It should also be a priority to use effective and safe cleaning methods as not to damage the metal. Some traditional and potentially damaging techniques to relieve silo buildup include:

Vibrators- Vibrators by their very nature and location have to first pass all their vibrational energy through the vessel wall. This can, firstly, result in severe loss of power and secondly propagate cracks and signs of wear, resulting in long lasting damage. There is also a possibility that vibrators can compact the material and further restrict material flow.

Air Cannons and Blasters- Used in groups, these devices employ an unidirectional blast of compressed air to try and remove blockages. The purchase of multiple units means that the initial cost is high as is the installation cost and the increased cost to satisfy their compressed air requirements. Furthermore, they do not provide a preventative or long-term solution to build-up.

Aeration Pads- At first glance, Aeration Pads seem to be a cheap and easy silo Bridging Solution, yet they provide a multitude of inefficiencies. Similar to the air cannons and blasters, they require multiple unit installations in each silo hopper. Secondly, once the materials being discharged come into contact with the aeration pads, they are prone to erosion and abrasive wear. It is therefore highly likely that an investment in regular replacements and installations will be needed.

Acoustic Cleaners use the latest and safest technologies to reduce material buildup in silos. Furthermore they are a preventative solution and can decrease the risk of silo compaction problems in the future. The service does not require down time on site and will operate during normal working hours. Our systems are also non-invasive and do not require the silos to be emptied. But how exactly does an Acoustic Cleaner relieve blockage in silo and hoppers?

It’s quite simple really. Sound waves are transmitted into the particulate matter or bonded material causing the solid particles to resonate and dislodge from the inner walls. Once dislodged, the silo buildup will then fall away due to gravity.

When considering how to clean a silo, there are many benefits to Acoustic Cleaning including:

Health and Safety- One of our main concerns when entering a site is Health and Safety. By using the latest and safest remote cleaning technologies, Acoustic Cleaning does not require a person to manually clean the structure, as was the case with other traditional methods. Acoustic cleaners also eliminate the danger of sparking as they are powered by compressed air rather than electricity.

Efficiency- Acoustic Cleaners ensure that material flows smoothly on the ‘first in – first out’ principle. The result is a consistent blend quality and less opportunity for discharge cross contamination.

Prevention: Primasonics latest cleaning technology takes a holistic approach to dealing with any silo and hopper issues, rather than concentrating on just one problem area. This should prevent any immediate future problems from arising as any potential compacted materials will be dislodged.

Convenience- As our systems operate from the top of a silo, it is not required for the bulk material to be emptied from the structure. Furthermore, the service does not require down time on site and will operate during normal working hours.

Non-invasive- Unlike vibrators and explosive cleaning methods, Acoustic Cleaners are designed to reflect sound from solid surfaces therefore no damage due or wear from intense vibrations will be caused. This way, we do not need to enter the structure.