Storage and blending silos

Achieving homogeneity in your kiln feed is vital. It affects everything, from the stability of your pyro process to the quality of your end product. The impact of a poorly balanced raw meal composition in kiln feed is felt on fuel efficiency, refractory life and, most evidently, your bottom line. So how do we make sure your raw feed remains consistent? The answer can be found in the CF (Controlled Flow) silo. Originally launched in 1981, this unique concept continues to deliver high homogenizing efficiency and low maintenance costs. Layers of raw meal are fed into the silo in a carefully controlled sequence that promotes mixing as the product moves through the silo. Key to the successful homogenization and discharge is the clever silo bottom, which is divided into seven hexagonal sections, each of which is split into six segments around a central outlet with a conical steel cone. The outlets feed the material continuously at different rates – giving you efficient and consistent homogenisation. Every segment has an aeration unit, ensuring easy and complete storage reclaim. As part of the kiln feed system, the raw meal leaves the silo via Airslide® conveyors and enters a mixing tank mounted on load cells, giving you complete control of your kiln feed for a stable and efficient pyro process.

Whenever you’re storing fine, powdery products, cohesion can be a problem. The materials stick together and to the silo walls, making it very challenging to reclaim. Manual clean-up is difficult and dangerous work – to be avoided at all costs. What you need is a silo that prevents agglomeration in the first place and assures the “First In – First Out” principle. We developed the CFI (Controlled Flow Inverted Cone) silo based on the successful design of the CF silo, which is used for raw material storage. The design makes use of individually aerated segments to keep material moving and prevent build-up. The CFI silo bottom is divided into 6, 8, 10, 12 or 14 sections depending on the silo diameter, which can be anything from 10 to 30 m. Each section is fitted with an aeration box and slopes 10 degrees towards its respective outlet at the base of the inverted cone. To keep energy consumption to a minimum, only two sections are aerated at a time. This combination of factors ensures easy and complete reclaim as well as low energy and maintenance costs.

Are you concerned about the environmental footprint of your cement storage? Silo reclaim can be surprisingly energy intensive – which is why we have developed the CFS (Controlled Flow Storage) or Flat Bottom Silo with incredibly low power consumption. The CFS silo bottom is divided into six sections, which can be anything from 10 to 16 m. Each section is fitted with an aeration box and slopes 15 degrees towards outlet at the centre. The aeration system can be made even more efficient with the addition of filters to prevent material from making its way into and blocking the entire system. The CFS design builds on our long experience with controlled flow silos to give you the ultimate low-maintenance option for your storage demands.

How do you handle the storage requirements of manufacturing multiple products? You could choose to have multiple storage facilities, if you have the space and the logistics to make it work – or you could opt for a more compact solution that can handle all your storage needs. The CFMI (Controlled Flow Multi-compartment with Inverted cone) silo was developed to be that flexible alternative. Based on our successful controlled flow technology, it guarantees complete “First In – First Out” and reliable reclaim of multiple products thanks to a truly adaptable internal structure. You can choose from silo diameters from 10 – 30 m, with multiple compartments designed according to your need (and civil engineering requirements). We’ve designed silos with two compartments, silos with four compartments – even silos with seven compartments. As with the CFI silo, each compartment floor is divided into aerated segments to ensure easy discharge. You can choose from the inverted cone type CFI silo bottom or a combination of a flat-bottomed CFS silo and inverted cone CFI design. The raised silo bottom leaves plenty of room underneath for the installation of packers, mixers and/or bulk loading equipment. With such a flexible offering, the best thing to do is talk to our experts about your needs so that we can help you decide on the optimal solution for your process.

Seasonal demand and supply can mean long-term storage of bulk products for 6 months or more. In that time, it’s common for material to build up, forming lumps and bridges that are almost impossible to displace without risky manual intervention. The MDS (Multi-Dom®) silo provides large storage capacities of up to 40,000 m3 and is especially suited to long-term storage. The silo bottom is divided into aerated segments that each feed to their own discharge point. Using a minimal amount of fluidizing air, each segment is aerated in turn to ensure stable flow. A special technology avoids material build up that would form lumps and bridges. Material can even be discharged and conveyed back into storage, ensuring that when the time comes for the product to be put to use, it is ready to go.

This space-saving system gives maximum storage capacity and includes space on the ground floor. The Random Flow™ Silo design uses six pie-shaped sectors, which are each subdivided into six aeration zones, and a timed discharge pattern to achieve continuous blending with the lowest possible energy consumption. Low pressure air is combined with gravity withdrawal, giving you maximum cleanout with power consumption as low as 0.07 kWh/metric ton for raw meal. And because there are no moving parts, it’s a very low-maintenance system.

The gentle blending action of the Airmerge™ system gives a near-perfect blend that’s even suitable for food applications. Air blending is achieved by use of a porous membrane over the entire bin bottom, four air plenums and a simple flow control system. Together they change the density of material in the fluidized bed of material to generate a gentle folding action and a near perfect blend. Higher air velocities in the blending quadrant lower the bulk density causing the denser material in the three fluidized quadrants to flow into it and be displaced upward in a continuously circulating bed. Airmerge blenders can be designed for batch or continuous operation to meet your requirements. This system is low maintenance, simple to operate and achieves complete cleanout.

For materials that are more difficult to blend, we recommend the column blender. It uses a ‘fountain flow’ technique to give a radial circulation capable of blending ultrafine powders, coarser sandy materials and products with a wide particle size distribution. Air enters the fully fluidized cone beneath the column, reducing the density of the material within, which is then displaced upward as the denser material from the annulus of the cone flows inward. This simple-to operate system has no moving parts and utilises a 60˚ cone design to achieve gravity discharge. One of the biggest benefits of the design is the flexibility in particle size range. But you can also accommodate different volumetric batch sizes by dividing the central column into two or more separate pieces.