Zenith and Coal Silo Inspection: A Match Made in Heaven

Coal silo inspection is typically an expensive and hazardous task, yet vital to ensure safety and help prevent failures that present serious risks to human health and life. Corrosion and defects are common, with welds within structures being of particular risk of corrosion.

Ensuring structural integrity in aging silos has always been a challenge – one that requires extended shutdown of the asset and substantial costs to effectively achieve. Such a vessel presents a considerable vertical space. Over recent years, many alternative ‘solutions’ to human entry for inspection have tried and failed to offer a viable alternative to human confined space entry.

That was, until the creation of Zenith by Interactive Aerial. Working on the basis of simplicity in combination with the latest technology, this vertical space inspection unit is revolutionising such tasks in a phenomenal fashion.

The Asset

Interactive Aerial was approached by Omaha Public Power District (OPPD) to provide a safe, effective inspection process to assess cone-to-skirt welds in several coal silos. The company wanted a proactive approach that would guard against incidents, such as the silo collapse in 2016 in Indiana, USA, where the failure of such a weld was deemed to have been the root cause.

The aim of the inspection was to identify any defects or corrosion in the weld. The assets had a known corrosion degradation risk, one that’s typical of carbon steel with stainless steel liners. Therefore, they needed the highest level of quality assurance.

The Challenges

Coal silos present a particular hazard due to the nature of the substance. However, there were more challenges specific to this task. In addition to this particular weld being prone to corrosion, the inspection needed to overcome:

• A highly complex internal structure geometry: There was no direct access to the welds that could be easily accessed by any kind of entry down the side surfaces
• Gaining extensive, high-quality visual data in a coal dust atmosphere: Despite the location, the need for accurate visuals was essential for a proactive approach to structural integrity.

Although reducing the length of time that such an inspection took wasn’t flagged as a high priority, managing to return the necessary data in less than the 2 days that had been set aside for the project would be beneficial.

The Solution

Zenith’s simplistic design and high payload meant it was the ideal tool for such an inspection. Thanks to multiple configuration options, Zenith was able to be set up and lowered into the centre of the silo shaft. From this position, coupled with its free-spinning ability, the camera was able to capture HD images and 4K video of the highest quality.

The following Zenith attributes meant that the required visual data of the cone-to-skirt weld within each silo was successfully achieved:

• Because the coal silos have wide shafts and highly reflective stainless steel, the Add-On Lighting Payload was deployed to ensure highly effective lighting within the asset
• The stabilised camera unit and 30x optical zoom captured the required data
• Once the correct setup was established, the complete inspection task for each silo was carried out in 25 minutes. 
• The battery-powered Smart Winch system worked in automation, meaning no manual operation was needed during each deployment.
• The complete inspection time was reduced to a single working day

The resulting inspection over-delivered OPPD’s expectations. Having seen the devastation caused by the 2016 Indiana incident, the company was keen to utilise a proactive maintenance approach. Using the Zenith enabled them to carry out accurate and swift inspections. They have determined that such technology will not only ensure the integrity of such assets but also save time and money, as well as increase the safety of their employees and inspectors.

Removing the need for confined space entry is a key reason for embracing the latest robotic technology. Equipment provider, Nexxis, is renowned for being at the forefront of such devices. They offer a solutions-based procurement model that’s designed to allow companies to take advantage of the right advanced kit for the job at hand.

Such innovation is key for companies to remain compliant and competitive in today’s economical landscape. 

Contact us to find out more about the Zenith 4K vertical inspection camera or any of our other custom solutions, or request a quote online.

Carry on reading Is Proactive NDT Inspection the Key to Great Asset Management? to find out more.