Dust Collection and Valves Blog

Is Your Hygroscopic Dust Causing Issues in Your Dust Collectors?| Aerodyne

Posted by Tom Hobson on Mar 29, 2021 8:45:00 AM

Hygroscopic dust can really grow on your nerves! I know the marketing department might take away my writing duties after that line. But seriously, hygroscopic dust can cause major maintenance issues in your dust collectors. Hygroscopic dust captures water vapor and droplets. This causes the particles to grow in size and weight, thereby making them easier to capture and remove from the airstream. However, if you are using filters, that’s where the problems start.

Filters capture dust in between the filter fibers and on the filter cake. When the dust is hygroscopic this can lead to issues. Dust particles in the filter fibers can grow when exposed to water vapor. They can then not release when cleaned, blocking the air pathway, or if they do release during cleaning the filters could be left deformed, allowing particles through the filter.

When hygroscopic filter cake is exposed to water vapor, it can plug up the filter, preventing air from passing through. This prevents any dust collection from the needed areas because there is no airflow to pull the dust into the system. And during cleaning cycles, the filter cake is strongly adhering to the filter and won’t fall off.

To prevent this from being an issue you will need to identify where the water vapor is coming from.

Airlock

If humidity is leaking in from the airlock then a low leaking airlock would be needed. Rotary valves have a small space surrounding the rotor allowing it to rotate without locking up. This area constantly allows air to leak around. A double dump valve which uses two flaps in series to isolate the hopper or a rotary valve with wipers can cut down on air/humidity leakage into the hopper.

Housing holes

If there are holes in the housing, high humidity outside air can leak in. Replacing or patching the holes will prevent air leakage. If corrosion is an issue, changing materials of construction or coating the hopper might help prevent future issues.

High water content in the compressed air used for cleaning

Install water traps and filters to keep the compressed air used for filter cleaning with low humidity. Often times this can cause greater issues than leaking airlocks or hoppers because the high pressure air goes through the filter, expanding the filter to shake off the dust. This delivers the humidity to the dust collected in the filter, which could cause greater pluggage.

High humidity air coming in with the dust

Installing a pre-filter will remove the majority of the larger heavier particles before they can see the filters. This minimizes the amount of material the filters contact, extending their life. Pre-filters such as cyclones and dropout boxes can often provide additional help on issues above and even extend the life of filters caused by high dust loading.

So when you have hygroscopic dust and your filters are plugging up too fast, try to isolate the area where humidity is coming.


 

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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Topics: dust collector, vacu-valve, airlocks valve, GPC Cyclone, arirflow, hygroscopic dust

Should I Test My Dust for Explosibility? | Aerodyne

Posted by Tom Hobson on Mar 15, 2021 8:45:00 AM

This is one of the most important questions you can ask. The answer to this question can require you to invest in expensive protection equipment or not, but that is much better than the loss of thousands of dollars in equipment, production time, and most importantly, employee safety. There are a few ways to answer this question. Some of which are safer than others. The main question you will need to ask yourself, is the dust combustible?

Is My Dust Explosive?

If the material can react with oxygen then there is a chance it can be explosive. However, just because it is combustible, doesn’t mean it is explosive. Generally if a dust is greater than 500 micron in size, it is not explosive. However, what if the dust is smaller than 500 microns?

The safest course is to send your sample into a test facility for a simple Explosibility Screening (Go/ No Go) test. This test will take a small sample and try to ignite it to see if the sample will explode. If it explodes then an explosion severity test should be performed, which provides data on the speed of the explosion (Kst) and strength of the explosion (Pmax). This data is very important to designing equipment that will prevent, contain, or divert explosions safely.

Some dust might be generated from material you got from a vendor, and they might have already done explosion testing on the material. You might be able to use this data for the design of your equipment depending on the process. The main thing being, what are you doing with your process? If you are sorting, grinding, drying, etc. the material then you can be changing the explosibility of the dust. If there has been a change, then the material should be tested again or you can assume it to be explosive and use the suitable published data.

The Explosibility of Dust

The explosibility of dust is highly dependent on the material size and humidity. A few examples would be aluminum. Spirals of aluminum from trimming wouldn’t be explosive, but a fine aluminum powder would be. Another example is wood dust. Dry wood dust is very explosive, while wood with a high water content is not.

You should not depend on your history working with the dust, because dust explosions are fickle. You might be working with dust for 20 years and have no issues and then suddenly there is an explosion. Or it might be the 1st time you work with a dust that an explosion happens. One thing is for sure, if you have had flash fires with the dust, you definitely should have it test for explosibility. A flash fire is a sign that you have an issue with your process and should do further investigation to make sure you won’t have an explosion and to prevent more flash fires.

Dust Hazard Analysis (DHA)

If your dust is explosive, you will then need to have a Dust Hazard Analysis (DHA) done on your process/ building, etc. The DHA reviews your process, operational and maintenance procedures, equipment, etc.   It then provides procedures, equipment changes, etc. to address the issues and provide for a safe process. OSHA will request a copy of your DHA during any inspection. So it is important that you have an answer to the question “Is my dust explosive?” and have something to back up the answer in case you are asked by OSHA, your insurance company, local fire inspector, etc.


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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Topics: dust collector, combustible dust, horizontal cyclone, GPC Cyclone, explosive dust, Dust Collector filters

Top 5 Questions to Ask When Considering A Cyclone Dust Collector

Posted by Tom Hobson on Feb 19, 2021 10:15:33 AM

Designing a dust collection system can be quite a daunting task. With so many collector options and so many application variables to consider, it is difficult to know where to begin. Cyclones are among the oldest and still most reliable methods of dust collection available. Because they require very little maintenance, have low up-front cost, and offer unmatched versatility, cyclone collectors remain a viable solution to many air-handling challenges. Although heightened environmental regulations and collection efficiency needs have shifted industry toward the use of filter-media collectors, cyclonic dust collection still plays a vital role in many air-handling systems. These five questions will help determine if a cyclone dust collector is right for your application.IMG_0688

  1. How big is my dust?

    Cyclonic dust collection relies on inertial forces to separate dust particles from an air stream. The larger and denser the particulate is, the greater its inertia. This is the reason cyclones have such high collection efficiencies when handling relatively large dust particles.

  2. How much dust is too much?

    Grain loading or dust loading refers to the amount of dust particulate that is suspended in a gas stream. This is typically measured in the number of grains per cubic foot of gas. This is an important number to consider when designing a pollution control system. Not only will this factor into the size requirement of a dust collector, but it will also determine the appropriate type of dust collector. The strict air pollution control standards in the United States often necessitate a “filter-media” dust collector, such as a bag house, for the final collection stage.

  3. Can I reuse the dust I am collecting? Particle Size

    Dust generated by handling dry bulk materials can be hazardous but also valuable. Unfortunately, most filter-type dust collection systems are designed for disposal rather than product reclamation. Filter media collectors such as cartridge filters and bag houses often do not allow collected particulates to be recovered for reuse due to contamination or particulate size issues.

  4. Do I have heat or humidity concerns?

    Air handling in manufacturing processes is often a delicate balance with a number of variables to contend with. Process heat and humidity in the air stream create a difficult challenge when it comes to dust collection. Collection of red-hot dust particulate is simply not possible with many bag houses because cotton filters are flammable and flame retardant filters can be costly.
  5. How much should I spend?

    Perhaps the most important and most difficult question asked when designing a dust collection system is how much to spend. The simple answer is, it depends. It depends on what the overall goal of the system should achieve. The best dust collection systems are those that were designed with several functions in mind: capacity, operation costs, maintenance costs, and product/ material value.


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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Topics: dust, dust collector, cleaning baghouse filter, horizontal cyclone, GPC Cyclone, splitScream Cyclone, Dust Collector filters, arirflow

How Do I Extend the Life of My Filters? | Aerodyne

Posted by Tom Hobson on Jan 27, 2021 3:15:00 PM

Dust collection filters such as the bags in baghouses, cartridges in cartridge collectors, and HEPA filters all filter out dust particles by collecting them in between their fibers. Dust builds up on the bags and cartridges to form a filter cake over the filter further restricting the ability of dust particles and airflow to pass through the filter. This restricting of airflow causes a pressure drop (resistance) which is directly related to the amount of dust built up on the filters. As the pressure drop increases, the airflow through the collector will decrease. Most baghouses and cartridge collectors have cleaning cycles which remove some of the dust from the filters keeping the pressure drop low.

The cleaning process on the filters usually consists of blowing higher pressure air through the filters, thereby causing it to expand slightly. This knocks off some of the top layer(s) of the filter cake which lowers the pressure drop through the filters. Other units have the filters connected to a mechanical shaking system. The airflow through the filter will be stopped during the cleaning process. The mechanical shaker system will gently shake the filters dislodging the dust to fall into the hopper.

Even with these cleaning functions, the filters will eventually plug up and significantly decrease the amount of air they allow to pass. This will starve the pickup points of airflow, allowing dust to escape and never enter the collection system. Depending on the application, this can happen within months or years of putting in new filters. The process of replacing the filters usually requires the system to be turned off. Cartridge collectors are usually easier to replace than bag, but either way the time and labor it takes to change are significant.

Ways to Extend Filter Life

It is therefore very advantageous to extend the time between filter replacements. The following are a few ways to extend filter life.

  • Install a pre-filter before the dust collector. The greater the concentration of dust getting to the filter, the faster the filter will plug up or fail. So if you can lower the dust concentration, you will extend the life of the filters. Pre-filters include cyclones and dropout boxes. Pre-filters remove most of the larger particles, leaving only the smallest to be handled by the filters.
  • Install pulse-on-demand controllers. A pulse-on-demand controller monitors the pressure drop across the filters. And when the pressure drop gets too high, the unit will activate the cleaning process until the pressure drop falls below a shutoff point. This extends life by preventing unnecessary cleaning of filters which can cause holes to develop in the filters. It also can save money on compressed air and keep the airflow within desired range.
  • Install different filters. Not all filters are the same. Some filters are designed to minimize issues with wet dust. Others have higher temperature ratings so they won’t degrade. If you are replacing filters too often, contact your filter supplier or system manufacturer to see if there are other filters that are more suitable. These special filters are more expensive, so it might be prudent to look at adding a pre-filter and pulse-on-demand controller to extend life even further at the same time.
  • If you are plugging up the filters with hygroscopic dust, check the collector housing for leaks that might allow humidity into it. Also, check the compressed air supply to make sure humidity isn’t being added to the system.
  • Install insulation on the dust collector if you have high humidity. Insulation will help prevent water vapor from condensing at night or during winter, thereby preventing water droplets from damaging the filters or causing dust to plug up in the filters.
  • Install a spark arrester before the dust collector. Depending on the process being vented, sparks can be pulled into the dust collector which, thereby cause the filters to catch on fire. Installing a spark arrester prevents this. Often times a pre-filter (cyclone or dropout box) provide the same protection.

If you are replacing filters too often then think about making some of the above changes to your system next time you are due to replace filters. That way you can extend your filter life and operate for longer periods of time without maintenance.

 


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



To improve efficiency and safety, there is no substitute for an on-site inspection by an experienced expert. Click below to start with a free 20-minute phone consultation by clicking the button.

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Topics: dust collector, cleaning baghouse filter, horizontal cyclone, GPC Cyclone, splitScream Cyclone, Dust Collector filters, arirflow

Common Dusts and Dust Collector Ranges vs Particle Size | Aerodyne

Posted by Tom Hobson on Dec 22, 2020 10:00:00 AM

This shows some of the particle size ranges of common dust applications along with the range where dust collectors work. As shown cyclones and dropout boxes will not get 100% of the dust.

There can always be some material getting through as the particle size distribution might always include smaller dust than normal. Wet scrubbers and filter collectors (baghouses and cartridge collectors) will collect the larger particles easily. However, installing a pre-filter cyclone to remove the larger particles will lower water usage (wet scrubber) and increase filter life (filter collectors).  


Five Signs Your Dust Collection System Needs a Pre-Filter


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


To improve efficiency and safety, there is no substitute for an on-site inspection by an experienced expert. Click below to start with a free 20-minute phone consultation by clicking the button.

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Topics: dust collector, horizontal cyclone, GPC Cyclone, arirflow, particle size

Why Are Airlocks Needed? | Aerodyne

Posted by Tom Hobson on Dec 16, 2020 10:00:00 AM

All dry dust collectors have a hopper which temporarily collects the dust while it is moved out of the system. The hopper usually has a flanged outlet on bottom which allows the dust to fall outside of the dust collector vessel. When you are deciding what to put under the hopper it is important to make sure that air doesn’t flow out of or into the opening while still allowing the dust to empty from the hopper. An airlock (discharge valve) is used to prevent this.

An airlock comes in a variety of designs. The most common is the rotary airlock while the simplest design is a trickle valve (Aerodyne Vacu-Valve). What these valves do is prevent the higher pressure air from going to the lower pressure air. Generally dust collectors are designed to be under vacuum. This prevents dust from escaping the vessel and helps protect the exhaust fan from being damaged by dust loading. However, some systems do have pressured dust collectors for operational reasons. Either way it is important that there be some kind of airlock under the hopper.

Dust Collector Under Pressure

A pressurized dust collector will blow air out of the hopper if no airlock is installed on the hopper. This will create a dust cloud around the dust collector. If indoors this will coat the surrounding equipment and become a nuisance to employees in the area. Plus it’s pretty unseemly having a dust collector spewing dust out in a facility.

Dust Collectors Under Vacuum

A system under vacuum, however, is much more impacted by not having an airlock. The airlock prevents outside air from entering the system. So if you don’t have an airlock the exhaust fan will begin pulling air into the system through the hopper. This does two main things. For one, it lowers the airflow at the pickup points that are collecting the dust. Air will flow the easiest path (much like water). So if you have an opening allowing air to enter through the hopper then air will take advantage of this. And since your exhaust fan doesn’t care where the air comes from it will pull much of the air through the hopper. This airflow means that there will be less air coming from the pickup points. This could cause insufficient dust pickup at those points and even dust buildup in the ductwork. The second issue is that any dust collected in the hopper could get re-entrained by the air entering through the hopper outlet and then leave the dust collector. This will decrease the system removal efficiency and could cause violations of permits, increased fan maintenance, etc.

So when you are operating a dust collection system, make sure that the dust discharge flange is installed with an airlock, that way you will have the system operating at its peak efficiency.


How Do Vacu-Valve Dust Valves Work?


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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Topics: vacu-valve, airlocks valve, GPC Cyclone, arirflow

Proper Placement of Your Dust Collector Depends on the Job | Aerodyne

Posted by Tom Hobson on Nov 24, 2020 10:30:00 AM

Dust collectors can be used for a variety of reasons. Some dust collectors are placed around applications that create dust such as saws, grinders, lathes, etc. The dust collector system is used to pull air from the area producing the dust via a hood and through some ductwork until it gets to the dust collector. The dust collector then separates the dust from the air. The cleaned air is then vented out of the dust collector through an exhaust fan and either outside or back to the facility. Other dust collectors are used to clean the air in a facility. The dust collector collects air away from the equipment and processes generating the dust. Many times this air is collected up near the ceiling of the facility. The air is then sent through the dust collector and vented outside or back into the building.

Whenever possible, you should try to capture the dust as close to the process generating the dust as you can. The reason is it is easier to capture the dust closer to where it is generated. If you are collecting the air near the dust generation equipment you will not have to collect as much air, which allows you to size a much smaller system, thereby saving money on capital expenses and operational expenses. Whereas if you are trying to capture the dust away from where it is generated, you will have to process more airflow to capture the dust.

However, there are times that you cannot place hoods right by the dust generating equipment. In those situations you will need to design your dust collection system so that it is big enough to capture the dust while keeping it as small as possible. This might mean building special hoods, using curtains, etc. all to help minimize the airflow required while maximizing the dust entrainment.

Dust collectors can also be used in vacuum systems. A vacuum system allows you to vacuum up dust around the facility without using portable vacuums. This might be advantageous when dealing with explosive applications, since most portable vacuums aren’t rated for explosive applications. And with the NFPA specifications requiring housekeeping of the dust facilities as a main action item, having vacuum systems for explosive dust is desirable.


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



To improve efficiency and safety, there is no substitute for an on-site inspection by an experienced expert. Click below to start with a free 20-minute phone consultation by clicking the button.

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Topics: dust collector, horizontal cyclone, GPC Cyclone, splitScream Cyclone, arirflow

Compact Cyclone Perks Up Coffee Roasters | Aerodyne

Posted by Tom Hobson on Oct 23, 2020 10:41:45 AM

A prominent coffee bean roaster is planning on building a new roasting facility in New Jersey. The head engineer contacted Aerodyne about trying to find equipment that could separate the coffee beans as they are pneumatically conveyed from one portion of the facility to the other. The engineer specified that the problem the facility was facing was space.

How Aerodyne GPC operates Differently in Coffee Industry

After sending over the specs of the application, Aerodyne concluded that the roasting facility could easily house a GPC-20 horizontal dust collector for the operation. The Aerodyne GPC Dust Collector operates differently than other dust collectors. A sloped spiral inlet directs the dirty gas stream toward a fixed ground plate and hopper of the dust collector.

The ground plate forces vortex reversal to occur in a much shorter space, eliminating the need for a long, tapered body. As the dirty gas stream strikes the convex ground plate, fine particulate that has not completely made it to the dust collector walls is deflected into the hopper. The ground plate also shields collected particulate from the forces of the vortex reversal, acting as a barrier between the separation chamber and the collection hopper. This innovative design enables a compact dust collector to operate at high efficiency, even when installed horizontally.

The GPC offers a unique dust collection solution. With the compact size and excellent removal efficiencies, it is an economical and low maintenance solution to removing dust and particulate from an air stream.


Aerodyne GPC Used in Coffee Roaster's Process


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


To improve efficiency and safety, there is no substitute for an on-site inspection by an experienced expert. Click below to start with a free 20-minute phone consultation by clicking the button.

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Topics: dust collector, horizontal cyclone, GPC Cyclone, arirflow, particle size

Particle Size Helps in Selecting Dust Collector | Aerodyne

Posted by Tom Hobson on Sep 30, 2020 9:45:00 AM

In dust collection one of the most important dust characteristics to define is the particle size of the dust. The larger the dust the easier it is to capture. While the smaller the dust particle the harder it is to capture and remove from the airflow. This applies to both heavy and light particles. What this means is that in order to accurately predict your removal efficiency, you need to know the particle size distribution.

Breakdown of Particle Sizes

The most useful particle size distribution includes a breakdown of the particle sizes under 50 microns in size. Most dust collectors will pretty much capture all or nearly 99% of particles greater than 50 microns, so it isn’t as important to know if you have 5% dust at 51 microns and 3% at 55 microns, a simple 8% over 50 microns would be effective.

However, when dealing with dust less than 20 microns, knowing the particle size distribution is very important. For example, some cyclones might get you around 85% removal of 10 microns dust but 60% of 5 microns dust and only 30% of 2 microns dust. So, if you have that 60% of the dust is less than 10 microns, it isn’t known how much of that is in the 2 microns ranger or the 10 microns range. This means that when calculating your removal efficiency, the estimated removal efficiency could range from less than 30% to 85%. The only way to know is to have a breakdown of the particle sizes.

Particle Size with Standard Deviation

Another way of providing a particle size distribution is to provide a mean particle size with standard deviation. This provides a decent approximation of the particle size. Personally, I would prefer the actual test data, because you are providing actual test data and not approximations. Depending on the process of dust generation, the approximation accuracy will vary. It also requires the person estimating the removal efficiency to calculate a particle size distribution. This takes more time and increases the chance of an error being introduced.

So, when you are looking to get your dust collector engineered, remember it is important to provide the equipment manufacturer with a particle size distribution. Often times you can send a sample in to a lab and within a week or so have a full distribution curve for a few hundred dollars. This will allow the manufacturer to better understand what they have to capture and select the best equipment for your application.


How Do Horizontal Dust Collectors Work?


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


To improve efficiency and safety, there is no substitute for an on-site inspection by an experienced expert. Click below to start with a free 20-minute phone consultation by clicking the button.

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Topics: dust collector, horizontal cyclone, GPC Cyclone, arirflow, particle size

Do Cyclones Replace Dust Collectors (Baghouses, Wet Scrubbers)?

Posted by Tom Hobson on Jul 24, 2020 9:14:12 AM

In most applications, cyclones do NOT replace baghouses, cartridge collectors, wet scrubbers, electrostatic precipitators, etc. Modern air pollution regulations require dust collectors to provide greater removal efficiencies in the PM2 and PM10 than most cyclones can provide.

How Cyclones work?

Cyclones collect dust by having the contaminated air enter (usually on a tangent) and spin around the cyclones walls until they get to the bottom. The air then reverses and spins up the middle of the vessel and leaves from the top, while the dust falls into the hopper.

The centrifugal forces on the particles and droplets, force them out towards the walls and away from the air exiting the center of the vessel. Cyclones provide high removal of the larger, heavier dust particles and moisture droplets.

The Benefits of Cyclones

Cyclones remove very high percentages of the larger, heavier particles. This means they often remove as much as 80%-95% of the total particles. However the removal efficiency of the smaller, lighter dust isn’t very high. The PM2 and PM 10 particulate will often get through the cyclone in high enough concentrations that the system won’t comply with state, local, and federal standards.

When installed in front of a dust collector (baghouse, cartridge collector, etc.) as a pre-filter, they significantly reduce the loading on the primary dust collector. This helps extend the operational life of the dust collector, increase removal efficiency, and decrease maintenance. Cyclones are often used to lower the loading on a dust collector (baghouse, cartridge collector, wet scrubber). The cyclone removes the large material, allowing the dust collector to get the high removal efficiency on the PM 2 and PM 10 particulate.


Aerodyne GPC Cyclone Dust Collector

View the animation of the GPC Industrial Dust Collector to see the compact, high efficiency cyclonic design. Unlike typical cyclonic dust collectors, the GPC Industrial Dust Collector uses a ground plate to force vortex reversal in a much shorter space, eliminating the need for a long, tapered body.


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


To improve efficiency and safety, there is no substitute for an on-site inspection by an experienced expert. Click below to start with a free 20-minute phone consultation by clicking the button.

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Topics: dust collector, Dust Efficiency Clinic, GPC Cyclone, splitScream Cyclone, Compliant System, Cyclones pre-filter

Aerodyne Environmental: Home of the Horizontal Cyclone and  Vacu-Valve® Airlock Valve

Inspired To Be Different.

At Aerodyne, we choose to take a different approach to collecting dust and handling materials. Our cyclones are unique in design to address common issues such as problematic dusts and space constraints. Our airlocks are chosen to fit your specific application instead of hastily installing traditional equipment options. We believe that when we see things differently, we can solve problems effectively. That's why so many people turn to us for help in solving their tough dust problems.

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