Effective control of fugitive dust at conveyor belt transfer
One of the major sources of fugitive emissions causing dust nuisance is at conveyor belt transfer points. It becomes all the more challenging in clinker silo extraction tunnels. For long it has become a challenge for cement plants or any other plant using a belt conveyor to effectively control fugitive emissions at these transfer points.
DCL has many a times introduced revolutionary concepts in providing rightly engineered productsù3 rope pulley systems, integral dust collectors (compact filter module) for bulk loading spouts, energy efficient silo aeration and extraction Systems-to suit the needs of the industry. One such concept also is a ventilation module or a VMV for efficient extraction of fugitive dust at conveyor belt extraction points.
Introduction to equipment
The VMV and VML ventilation modules are an excellent choice for dust control when used directly at the source: conveyor head chutes, ventilation of enclosed conveyors, screeners, mixers, silos and batching bins.
The exhaust fan is directly mounted to the assembly, eliminating the need for a remote fan placement. This unique design provides internal velocities lower than what you´d expect in conventional designs. This gives you less load on your filtration media. The filter elements are automatically cleaned during operation with a conventional 80-100 PSI pulse jet system. The unit can also be provided with a final clean feature. When activated at the end of each loading cycle, it fully cleans all elements, eliminating residuals.
Filter media is available to accommodate most applications. Pleated design, spun-bonded media features a smooth surface finish with exceptional dust cake release. The filter surface is calendared and compacted to resist penetration by collected particulate. This results in better cleaning efficiency and faster return to operating airflow after the cleaning cycle than traditional media. DCL offers a large selection of ventilation modules from 85 to 750 sq ft of filter media. Exhaust fans can be sized up to 6,000 CFM.
A choice of construction materials allows you to effectively handle all types of products-fine, granular, lumpy, abrasive and corrosive-and difficult dusty or sanitary applications. You can also choose from the electrical options that are best suited for your environment: NEMA 4, NEMA 4X, NEMA 7, NEMA 9, 120V/220V control, 460V/415V power, etc.
Principle of operation: Dust laden air enters the filter module under suction from the fan. Dust is captured by the filter cartridges, automatically cleaned from the filters, and deposited back into the flow stream.
Advantages of ventilation module
Ease of mounting: DCL VMV, which is integral with the blower, is mounted right on top of the conveyor skirt board.
Elimination of ducting work: In a DCL´s VMV, ducting work is completely eliminated, can be installed with an integral blower.
A bag filter would require ducting work from dust extraction point with bends creating a pressure drop across the system never achieving the desired efficiency, resulting in inefficient dust extraction Elimination of RAV´s, screw conveyors: In a DCL, VMV the product is pulsed back right on to the conveyor eliminating the need for these auxiliary systems, which saves your capital and maintenance costs for the same. In a conventional BagFilter, upon accumulation of dust in the bag filter hopper, it is necessary to bring the collected dust (product) back into the main stream, which requires another conveyor and RAV´s (either an air slide/screw conveyor). Apart from the capital cost involved in installing these additional systems, maintenance of the same is also another effort and costs money too, every year.
Energy savings: Here too the capital cost and the running costs will be high. In case of a DCL VMV, it is installed with the blower at source point, since there is no ducting work, static pressure will be reduced resulting in selection of a blower motor of lower capacity. Further, DCL VMV´s with integral blowers will be under operation only on the belts that are running. Hence DCL VMV´s are much more economical to install and operate in long term and short term.