Dust collection systems require the proper airflow to operate correctly.  Without the correct air flow, dust will not be removed from collection points and the collection equipment (baghouse, cartridge collectors, cyclones, etc.) will not operate with maximum efficiency. However, if too much air is being pulled through the system, a variety of issues might ensue, such as product being lost, removal efficiency lowered, utility usage increased.

Conventional Way to Measure Airflow

The normal way to measure airflow is to insert a pitot tube in the ductwork to measure the air velocity in an airstream, and then calculate the velocity (and airflow).  This is a manual process that requires a trained individual.  It is time consuming and to a certain degree an art, since the velocity in a ductwork changes depending how close to the wall you are.

Effective Way to Measure Airflow

Obviously, you cannot walk next to a piece of equipment or meter and check the velocity through the ductwork.  However, if you have a cyclone dust collector you can.  Cyclone pressure drops are based on the airflow through them.  The more air you send through a cyclone, the higher the pressure drop.  Each cyclone design has its own equation to determine pressure drop based on the airflow.  With this equation, you can estimate the airflow based on the pressure drop in your cyclone.

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The GPC Dust Collector is an efficient way to handle your dust collecting needs. Simply click below for direct access to the GPC spec.

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Exhaust Fans: The Motive Force of a Dust Collection System

In this video, Aerodyne discusses how system changes and fan performance affect your dust collection system.

 

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To learn more about which dust collector, please contact our experts at 440-543-7400 or visit our website: www.dustcollectorhq.com.

The key function of a collector is to remove the maximum volume of dust from the airstream.  Additionally, an important part of the process is keeping the removed dust from re-entraining.

Baghouses and Cartridge Collectors

Baghouses and cartridge collectors collect the dust on the filters and during cleaning, the material is knocked loose and falls to the hopper.  How well the material falls to the hopper is dependent on the dust that is being collected, the can velocity (speed of air between the filters) in the baghouse, and the design of the baghouse.  

Basically, if the dust is very light and/or irregular in shape, then it might not easily fall to the hopper, instead it might float (like a leaf).  This could cause it to be re-entrained in the airflow and go back on the filter.  If the airflow is very high then the can velocity could hold up dust after cleaning, thereby causing re-entrainment of the dust.  The design of the unit can affect re-entrainment as well.  Some units have the dust coming in the unit below and at a rather high speed, which can increase dust re-entrainment.  Others will have the dust entering from the side of the filters, thereby being at a much lower velocity and out of the path of falling dust.

Cyclones

Cyclones use centrifugal force to push the particulate dust outward.  Most cyclones also use tapered walls to concentrate the dust as it gets lower in the cyclone until it falls into the hopper, while the clean air leaves the cyclone through the center.  The point where the air stops traveling down the walls and begins to travel up the center is called vortex reversal.  Depending on dust size, concentrations, and cyclone design, dust can be re-entrained by the clean air leaving the cyclone.

Wet Scrubbers

Wet Scrubbers are very good at low re-entrainment.  This is because when the dust meets a droplet, they become one larger particulate and then fall out of the airstream easier.  Most well designed wet scrubbers have a mist elimination section that will further collect droplets before leaving the collector.

 

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5 Signs Your Dust Collection System Needs a Pre-Filter

Watch the video from the Dust Efficiency Clinic discusses how using a pre-filter will optimize your dust collection system. 

 

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To learn more about which dust collector, please contact our experts at 440-543-7400 or visit our website: www.dustcollectorhq.com.

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