We talked about the importance of proper enclosures in conveyor transfer points. However, there are many cases where enclosures are properly designed and there’s adequate ventilation, yet dusting soon becomes a problem. The ventilation system always takes the blame, but is the problem really due to poor ventilation?
Engineers in charge of material handling design often design chutes and loading points without considering the long term impact on the ventilation system.
Take the loading of a belt. If the chute and loading point are poorly designed, the enclosure seals are soon worn out. A resulting gap between the enclosure and the belt adds to the open area originally considered by the designer, which proportionally reduces the ability of the ventilation system to suction fugitive dust emission. In more extreme cases, transported material even shoots out of the enclosure, leading to excess dusting and material accumulation nearby. Yet the ventilation system is blamed for the mess.
So what to do? Two simple solutions in conveyor loading include muckshelves and rockboxes. These minimize impact and wear on the conveyor and center the material loaded on the conveyor, extending the life of the enclosure seals and maximizing the performance of the ventilation system.
Rockboxes and muckshelves are not part of your ventilation system, but can sure have an impact on its performance.
Call one of our expert engineers to discuss your application and possible improvements.
Dr Vent Goode
Enclosures should efficiently cover the area of dust generation. Although they don’t look like they are even a part of your ventilation system, they are absolutely required, and their design is extremely important for the overall performance of your air pollution control equipment.
If you could completely enclose a source of dust generation, no ventilation would be required simply because there would be no openings where dust could escape. From this statement we can generally conclude that the more you enclose a source of dust generation, the more you reduce dust emissions problems. This is true, but there are limitations that need to be considered.
Take a belt conveyor transfer point, where dust is generated mainly where the material impacts the conveyor being loaded. An enclosure contains the cloud of dust, but the transfer cannot be sealed because openings are required for material to enter and exit the enclosure. So your installer hangs rubber skirting down to the belt surface in an attempt to eliminate all openings. This is a problem because the skirting then drags on the conveyed material, creating an additional point of dust generation and greatly affecting the performance of your air pollution control equipment.
Proper design guidelines recommend a 2” clearance between the skirting and the material conveyed. Sure, that’s an opening, but it’s a necessary opening. The ventilation system is designed to pull ambient air through these controlled openings, and it is this incoming ambient air that keeps fugitive dust from escaping. The incoming air sweeps fugitive dust to the baghouse, which is exactly what your ventilation system should be doing, keeping fugitive dust from escaping, not suctioning conveyed material.
Enclosure design is critical for the performance of your system and can be the main reason for poor performance in a ventilation system. Details vary greatly depending on the application and sometimes these details can be counter-intuitive, so count on experienced IAC engineers to help you optimize your installation for maximum performance.
Dr. Vent Goode
Industrial Accessories Company was asked to provide nuisance dust collection add-on equipment to a fleet of sand movers operating in the Marcellus Shale play. The equipment was made mobile to allow rapid deployment along with the sand movers.
The installation was developed to address concerns related to controlling dust generation created during pneumatic filling of the sand movers. Removing harmful particulate from the air benefits overall health and safety for all operating personnel at a Frac site. The collection system allows for up to seven pneumatic trailers to fill the sand movers simultaneously. IAC can design and supply equipment into new Frac sanding systems or retrofitted to existing equipment. Read more about IAC Frac Sand Technology here.
IAC Dust Collector Mitigates Frac Sand Exposure at Marcellus Well Sites