Furnace and industrial services Dickinson Group offers a highly specialised service for cleaning contaminated and clogged up bulk storage containers to manufacturing companies across sub-Saharan Africa, the Middle East and Asia.
For every plant to operate at maximum process efficiency and optimum point, it is imperative that silos run free of any blockage or contamination. Dickinson Silo Cleaning Services division provides safe and efficient methods for the removal of build-up in silos and bulk containers.
These services – which involve the safe and efficient removal of compacted materials – also include consulting on how to implement preventive maintenance procedures and adopt proper cleaning schedules.
Dickinson explains that cleaning work is carried out using cutting-edge equipment and is fast, efficient and safe. Dickinson services are designed to safely remove compacted materials from silos, bins, hoppers, tanks, reactors and chimneys of any size or shape.
Substances kept in silos attract moisture, which causes the material to bind and adhere to the walls or form clumps. As the moist product dries, it can harden and start to break up, producing lumps that can block the valve outlets.
This results in the build-up of debris, which restricts the flow of material, causing reduced capacity and continual production stoppages. Lumps can be removed from the valve areas or air slides, which is a typical case for Dickinson’s Silo Cleaning Services. The company cleans cement, coal, soda ash, fertiliser, plaster, animal feed, salt or clay.
Specialist expertise is critical to the success of any silo management system. Through innovation and new technologies, Dickinson Silo Cleaning Services can replace the traditional unsafe methods used, by avoiding having personnel work in unsafe confined spaces.
Dickinson says that, in addition to providing relevant experience and know-how, silo cleaning services require highly specialised equipment. It adopts a combination of specialist cleaning systems, which create a number of advantages.
Some of the safety advantages include no human entry into confined spaces, making it 100% safe; the safe removal of flammable, explosive, hazardous or toxic product; no special safety measures required, only standard operating procedures; and provision of a silo cleaning system that does not cause damage to facilities or the environment.
There are hygienic advantages too, such as it being a dry process that uses no water and no chemicals, which is environment-friendly and poses no contamination risk. Dickinson explains that regular cleaning will ensure that quality control of all storage areas is maintained and that there is a higher standard of cleanliness. This ensures that silo cleaning is undertaken in a timely manner prior to possible product contamination, material build-up and lost bin capacity.
These advantages are all economic and provide reduced costs. This is connected to the falling away of the need to comply with entry into confined spaces legislation, reclaimed or recycled product that is non-flowing but usable, which could reduce cleaning costs, improved storage capacity by eliminating blockages, and turnkey solutions to enable the reduction of in-house labour costs.
Cleaning silos faster than with conventional methods is also of great benefit as reduced time is taken out of productive work. The new cleaning methods mean that Dickinson Silo Cleaning Services is able to clean more than one silo at a time, remove materials from scaling to total blockage and deliver production enhancements by overcoming blockages without disrupting production.
Dickinson Silo Cleaning Services division adopts a combination of silo cleaning technologies, including the Silo Whip system, which can be used in combination with the Cardox carbon dioxide (CO2) system. It explains that after a period of time, the material inside a silo tends to bond or harden, owing to the presence of moisture or contact with foreign environmental elements.
It then starts forming a build-up along the sidewalls and at the base of the silo. This build-up continues to propagate and as the years progress, without proper maintenance, the situation can lead to significant problems.
The layer of build-up that is formed over a prolonged period reduces the actual capacity of the silo. Dickinson says there are specific areas where the build-up generally occurs, for example, the sidewall of the silo. The layer of build-up that bonds onto the sidewall begins to thicken. This symptom is known as coating, or overhang if the layer becomes too large.
The second main area that can have a layer of build-up is at the base on the silo. The build-up forms at the base of the silo along the cone and sidewalls. Dickinson explains the build-up becomes more compact and harder at the bottom as it stacks up higher. This is known as a hill formation. When a hill formation becomes too high and starts to join other hills, the effect known as bridging occurs.
Dickinson says that the Silo Whip system is powered by hydraulics and controlled from the top of and outside the silo, which eliminates the need for workers to enter. With health and safety in mind, this method is the safe alternative when performing cleaning without entering the silo.
The whipping head, which is suspended inside the silo from the top, efficiently clears build-up using an air-driven or hydraulic rotary cutter, with a 360° rotation and an operating depth of up to 50 m. A range of cutters are used depending on the type of material to be cleaned. Cleared material simply falls to the base of the silo for extraction.
The Cardox CO2 system has a variety of different tubes for specific applications. Cardox tubes are filled with liquid CO2. Dickinson explains that when energised by the application of a small electrical charge, the chemical heater instantly converts the liquid CO2 to a gas.
This conversion expands the CO2 volume and builds up pressure inside the tube until it causes the rupture disc at the end of the tube to burst. This releases the CO2, which is now at 600 times the original volume, through a special discharge nozzle to create a powerful heaving force at pressures of up to 40 000 psi.
Dickinson explains that the instantaneous build-up in pressure reaches the yielding pressure of the rupture disc, which bursts, releasing a heaving mass of CO2 and breaking the surrounding material. By selecting the thickness of the rupture disc, the power of the tube can be regulated to suit all conditions. After recovery, the tube, heater, washer and rupture disc are replaced, the liquid CO2 is recharged and the tube is ready to be used again.