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Baghouse Tips with Dr. Vent Goode

Are your system’s ventilation hoods effective?

Vent hoods are the point where gasses are suctioned into your ventilation system.  They are a very important component in the performance of your baghouse and discharge system, yet designers often pay little attention to their design and location.

To understand hooding design, first we need to understand the purpose of your ventilation system.  Or more precisely, what it’s not supposed to do.  With a few exceptions in process equipment, the ventilation system is NOT intended to suction dust.  Its purpose is just to keep your process equipment or your enclosure under negative pressure.  Some dust will inevitably end up in the baghouse, but it’s not intended to act like a vacuum cleaner.

Hoods have two basic functions:  They should minimize material carryover and they should minimize pressure losses at the pick-up points.  These two objectives can be accomplished with proper hooding design.

In a nutshell, the larger the hood, the lower the amount of dust suctioned.  And the more tapered, the lower resistance to flow.  There is obviously a physical and cost limitation, so rule-of-thumb guidelines are presented in design manuals to make them reasonably sized.  The typical recommendation is to form a square box as wide as the enclosure allows before tapering to the round ductwork.

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Hooding position is also important to minimize material carryover.  Even a properly designed hood will end up suctioning excess material if it’s placed at the wrong location.  In general, hoods must be placed away from the source of dusting, as shown below.

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Properly designed and properly positioned hoods can make a big difference in your systems’ performance to reduce wear on filter bags and discharge system overload.

Call us to discuss your application with one of our engineers today!

Baghouse Tips with Dr. Vent Goode

Is your material handling collaborating with your ventilation system?

Enclosure-Post

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.

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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.

Needs editing 2Belt-Conveyor

Call one of our expert engineers to discuss your application and possible improvements.

Dr Vent Goode

Baghouse Tips with Dr. Vent Goode

Baghouse Tips with Dr. Vent Goode – Are Your Enclosures Properly Designed?

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

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Story of a Baghouse and the Quick Quote Configurator

A case study on how IAC’s Quick Quote Configurator can save time and money

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Upon repurposing an existing silo to handle a new material, this large midwestern cement plant looked to IAC to help find a solution for their dust collection needs. Utilizing IAC’s Quick Quote Configurator our team was able to quote and deliver a new, high efficiency pulse-jet dust collector within 5 weeks of receipt of a purchase order.
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This particular project presented some unique challenges that our service crew had to overcome. The plant’s old shaker style dust collector was housed at the top of a 180ft silo.
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Service team members first had to remove the roof of the housing in order to access to the old collector.
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In order to repurpose the unused silo, this cement plant wanted to also insure that their dust collection met the new NESHAP requirements. Removing the old shaker collector would improve filtration efficiency and decrease maintenance costs.
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The existing shaker dust collector was placed on a flatbed and removed for proper disposal.
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IAC’s custom dust collector being hoisted into position.
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Another unique challenge for this project were the space constraints. IAC’s Quick Quote Configurator was able to accurately meet the sizing requirements within inches of the confined quarters of the silo housing.
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The new pulse-jet collector was carefully lowered into place a top the 180ft. silo.
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Lowering the new dust collector into its final position. A tight fit that needed to be assessed accurately and efficiently to meet IAC’s scheduled completion date.
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Now complete, this large cement company will no longer have to worry about filtration efficiency or meeting the new NESHAP requirements. IAC’s Quick Quote Configurator was able to exceed our clients expectations and deliver a new high efficiency customized dust collector in 5 weeks. Presented with unique challenges our team was able to accurately assess the specific needs of our client and give a personalized solution to their dust collection problems.

QuickQuote

IAC News

IAC Mitigates Frac Sand Exposure at Well Sites

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

IAC Air Pollution Control for Marcellus Shale Frac Sand Well