Dust Collection and Valves Blog

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

How To Determine the Cost of a Cyclone - Part 6 | Aerodyne

Posted by Tom Hobson on Apr 30, 2020 9:15:00 AM

Part 6: Scope of Supply

Cyclones do not stand alone in most applications.  They require additional equipment for them to work.  Depending on your application, equipment can include an airlock, exhaust fan, explosion protection, instrumentation, insulation, vibrator, and even ductwork.  The cyclone can be purchased as a system with all the equipment required to operate or it can be purchased by itself and integrated into an existing system.  The system is then put together by the end user or a 3rd party.  Many times, the sum of the accessory equipment is greater than the cost of the cyclone.  A brief description of the potential accessories and how they affect the cyclone is below.

  1. Airlock

    An airlock is essential for the proper operation of a cyclone.  It isolates the cyclone from the outside atmosphere.  Without it, material will fly out the bottom or get re-entrained in the system.  Airlocks could be a simple extended hopper (55 gallon drum), rotary valve, or specialized valves like the double dump valve or trickle valve.  Special designed valves are available for quick cleaning applications and explosive applications.
  2. Explosion Protection

    Explosion Protection is a very important consideration for dust collectors as about 70% of dusts are explosive. The equipment that protects against explosions can add significant cost the cyclone.  Explosion protection equipment such as explosion vents, isolation valves, chemical suppression, and isolation systems can all quickly increase the price of a cyclone.  This equipment is required for explosive applications. 
  3. Exhaust fans 

    Exhaust fans are required on every dust collection system. They provide the motive force required to pull air through the system.  When selecting the fan, be sure to take into account all ductwork and equipment.    It is best to install the fan downstream of all dust collectors so that the most efficient impeller designs can be used.  This will save money on operational costs.  However, if the fan needs to be installed in high dust areas, there are impellers designed for these operations.
  4. Instrumentation 

    Instrumentation for cyclones are rather simple compared to other dust collectors. The main instrumentation used on cyclones are differential pressure gages/transmitters and level switches for the hoppers.  Explosive applications can have special instrumentation and some applications will monitor temperature and humidity for equipment downstream of the cyclone.  But for most standard cyclone applications, differential pressure is the only recommended measurement.
  5. Insulation, Heat Tracing, Steam Jacketing
    Insulation, heat tracing, steam jacketing are required for special applications. These can add significant expense to the cyclone.  Insulation and heat tracing can be done at the fabricator but usually are done onsite to prevent damage in shipping and installation.  Steam jacketing must be done in the design and fabrication phase and can add significant cost to the cyclone.
  6. Vibrators or Air Jets
    Vibrators or air jets are used for applications where material bridges in the hopper. Vibrators can usually be installed after installation and will help keep the hopper from bridging up.  Air jets blast air into the hopper, breaking up any bridging and letting material flow out of the airlock.  It is best to have the connections for these to be included in the cyclone design and installed once on site.

In summation, cyclone design and costs are based on the size and construction required in your specific application.  Special applications can require costly equipment and design changes that will increase the cyclone cost significantly.  When selecting a cyclone for your application, be sure to include all the factors in to your cost estimate so you are can accurately determine your budget.



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, NFPA 652, horizontal cyclone, GPC Cyclone, splitScream Cyclone, arirflow

How To Determine the Cost of a Cyclone - Part 4 | Aerodyne

Posted by Tom Hobson on Mar 27, 2020 10:14:34 PM

Part 4: Application Requirements

Cyclones also need to be constructed so that they meet the specifications and requirements of the applications they are going in.  Some applications, like woodworking or where the material being collected is waste, don’t need any special constructions.  Applications such as food and pharmaceuticals can be very specific.  Every application, customer, process, and facility has their own set of requirements.  These could include a special quick clean access or a higher weld spec to prevent accumulation in the vessel.

  1. Quick Clean

    Quick Clean design allows for the cyclone to be easily accessed for cleaning. It is often used in food and pharmaceutical applications.  These applications usually have a strict cleaning protocol and/or require cleaning between batches.  The design changes required for quick clean design can often significantly increase the price of a cyclone.  Often times it will require redesign of the standard cyclone to allow access and minimize material buildup.  Horizontal cyclones are often best for these situations.
  2. Special Welds

    Special welds are required in most food applications. The welds are often areas where material can build up and contaminate the material being collected in the cyclone.  To prevent this, the welds are often required to be ground down.  This is a time consuming process and is done individually with power tools.  Depending on the specification, special welds can often significantly increase the price of the cyclone, even as much as doubling the cost.  Often times, the welds will require specific welders in a shop to work on the unit, thereby increasing the lead time and cost.  When you are specifying special welds, it’s often a good idea to have a sample or a picture of the weld you are looking for so the fabricator and end user are on the same page.  See the drawing below for an example of a sample.
  3. Special Finishing

    Special finishing of the materials of construction is another requirement in many stainless steel applications. Some food and pharmaceutical applications require the metal to be finished or polished to a certain specification.  Usually, the internal finishing is the most critical due to it being in contact with product, but often times the facility has a specification on the external too.  This is often for cleaning and uniformity in the facility.  Special finishing of the metals can often significantly increase the price of the cyclone.  Often times, with the higher finishes allowance has to be made in the pricing for discarding material that doesn’t meet to specification after it has been worked on.

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, NFPA 652, horizontal cyclone, GPC Cyclone, splitScream Cyclone, arirflow

Horizontal Cyclones: Solutions for Space Limitation | Aerodyne

Posted by Tom Hobson on Sep 30, 2019 10:30:30 AM

If you are like many plant engineers who are working within the confines of a limited work space, rest assured that you don’t need to compromise on the efficiency of your industrial dust collection system. A traditional, high-efficiency cyclone is not the best solution for facilities with low ceilings.

Space Limitation

If space limitations prevent you from properly orienting this type of cyclone in an upright position, this will result in a loss of efficiency due to particulate settling on the side of the collector and being carried out with the exhaust gas. Attempting to solve this problem by installing your vertically oriented dust collection cyclone outdoors may encourage condensation that can shorten service life and reduce efficiency.

Horizontal Cyclones

Today, more plant engineers are choosing a horizontal configuration for reliable, high-efficiency dust collection. These options include the Aerodyne GPC Cyclone and counter-cyclonic dust collectors, such as the Aerodyne SplitStream™ Dust Collector.  The SplitStream™ Dust Collector uses a secondary air stream that directs material toward the collection hopper, and may be installed horizontally with virtually no loss of efficiency.

Because this design does not rely on gravity to bring the dust to the hopper like conventional cyclones, its operational efficiency is not affected by horizontal installation. In addition, this type of dust collection system may be suspended from a ceiling, conserving valuable space on the manufacturing floor.

The SplitStream™ Dust Collector the ability to increase/decrease process temperature while collecting dust. The unique counter cyclonic design element of the SplitStream™ Dust Collector ensures that a minimal amount of particulate comes in contact with the interior walls. This eliminates excessive wear and enables abrasive particulate collection.

 


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.

Free Consultation

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Topics: dust collector, NFPA 652, horizontal cyclone, GPC Cyclone, splitScream Cyclone, arirflow

How Important is the Airflow in a Dust Collection System

Posted by Tom Hobson on Feb 21, 2019 9:27:16 AM

 

The airflow in a dust collection system is extremely important, since the air collected at the hoods is removing the dust from the affected areas.  This air is then sent to the dust collector to remove the dust from it.  While it is always desirable to use the least amount of air as possible in your dust collection system, you must have enough air so that it is actually doing the job it is meant to.   If not enough air is going through the system, you will not capture all the dust from the pickup areas, thereby allowing dust to escape into the facility, cause health / nuisance issues and/or fire hazards.  If the airflow is too high, you could be picking up product/ raw materials, wasting energy and increasing maintenance issues.

There are many reasons that the airflow through a dust collection system can change.  A few of them include:

  • Environmental changes – temperature, humidity, etc.
  • Changes in the system – such as opening/ closing dampers, dust buildup in the ductwork, damage to the ductwork and/or hoods.
  • Dust collection issues – such a plugged filters, old filters, holes in the filter, etc.
  • Damage to the exhaust fan – such as bearings, damaged impellers, etc.

Unlike liquids, there is no easy and inexpensive way to monitor airflow in a dust collection system.  The most common way is to periodically manually measure the airflow by inserting a pitot tube in the ductwork and measuring the air velocity.  The airflow is then calculated.

One option to monitor your airflow is to install a cyclone pre-filter ahead of the filters.  A cyclone’s pressure drop increases as the airflow increases in them.  Usually the manufacturer of the cyclone can provide a curve, showing the relationship between the pressure drop and the airflow.  So if you monitor the pressure drop through the cyclone, you will notice if the airflow suddenly increases or decreases.  And if the pressure drop drifts too far from a certain pressure drop you will know to troubleshoot the system.

To learn more about the different types of Dust Collection methods,  please contact our experts at 440-543-7400 or click on the button below to get our whitepaper: Top 5 Questions To Ask When Considering A Cyclone Dust Collector.

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Topics: dust collector, cartridge collector, horizontal cyclone, pre-filter, dust collection system efficiency, maintaining air valves, splitScream Cyclone

The Effects of Humidity & Compressed Air on Dust Collectors

Posted by Tom Hobson on Jan 29, 2019 8:57:26 AM

Dry dust collectors and humidity don’t react well together.  Baghouses and cartridge collectors operate by having dirty (dusty) air enter the housing.  Multiple filters (bags or cartridges) are located in the housing.  The air travels through the filter and then exits the dust collector.  The filters are a mesh of fibers that allow air to travel through small holes, while dust is too large to pass.  The dust builds up a layer (dust cake), further limiting the subsequent dust’s ability to pass through while allowing the air to pass.  From time to time the dust collector will clean the filters by shaking them or using compressed air to expand them.  This causes the outer layer of the dust cake to fall off.

Humidity can cause problems in the process described above.  Humidity is a way to express the amount of water in the air, (the higher the humidity, the higher the amount of water in the air).  When high humidity air enters a dust collector with fabric filters, there is a chance that the water vapor will condense and create water droplets or the dust on the filters will absorb the water as the airflow passes through.  Many dusts change their physical properties when the water content increases.  Some become sticky, some become hard like concrete, etc.  When this happens to the dust cake, it affects the ability of the air to pass through and the ability of the dust to fall off during cleaning.

When dust becomes sticky, it will adhere to neighboring dust particles and not want to fall during cleaning.  Dust that becomes hard (like concrete) will prevent air from passing through.  When one of these issues develop in a dust collector the pressure drop across the dust collector will increase.  Over time, an increased pressure drop will lower the airflow being pulled through the system.  This will decrease the airflow being picked up at hoods, therefore lowering dust collection at where operators are located.

Humidity can also be introduced in the dust collector in the compressed air.  When air is compressed, the temperature of the air increases, thereby increasing the water content of the air.  The compressed air is at its saturation point.  As the air moves through the line, it cools, thereby condensing water in the system.  If additional drying technology isn’t installed, the compressed air will have water droplets in it as it is used in the dust collectors.  This will cause the filter cake to wet and cause issues as described above.  This is why it is important to dry compressed air when dealing with dust that is affected by water.

However, sometimes no matter how you treat your compressed air, you continue to have issues.  This could be because the airline travels outside and in winter time it gets very cold. It could be because you are located near a large body of water, and humidity is high.  One way to minimize the effect on your dust collector is to minimize the dust getting to your dust collector.  Cyclone pre-filters are ideal for these applications.  Cyclones collect dust and water droplets using centrifugal motion.  This means they aren’t affected by the changes to the dust as a filter is.  Cyclone pre-filters can often remove up to 80% of the dust before a dust collector with filters.  This means you can lower the number of water droplets going into your dust collector and minimize the cleaning required, thereby not getting as much water from the compressed air system. 

To learn more about the different types of Dust Collection methods please contact our experts at 440-543-7400 or click on the button below to get our whitepaper, Top 5 Reasons to Use a Cyclone as a Pre-Filter.

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Topics: dust collector, cartridge collector, horizontal cyclone, pre-filter, dust collection system efficiency, maintaining air valves, splitScream Cyclone

Cyclonic Dust Collection Can Reduce Fabric Filter Baghouse Maintenance Costs and Downtime

Posted by Tom Hobson on Dec 7, 2018 11:15:00 AM

At one time mechanical dust collectors were the industry standard in dust collection and air pollution control. However, with an ever increasing focus on air quality, EPA regulations regarding dust collection have steered the manufacturing world toward the higher efficiency capabilities of fabric filter baghouses, cartridge filters, and other dust collection equipment utilizing filter media. This change has undoubtedly helped to reduce the amount of harmful emissions released into the atmosphere in manufacturing processes. Unfortunately, the use of these fabric filter baghouse collectors is not without cost. The limitations of filter media such as moisture, heat, and high particulate volumes have added to the challenges of successful dust collection. Additionally, the high cost of bag or cartridge replacement, maintenance issues, and expensive pulse-jet controls to clean filter media can add up. The solution to these headaches for many has been the use of mechanical dust collectors before final-stage filtration.

Mechanical dust collectors use a cyclonic air flow to separate particulate from an air stream. The centrifugal force created by the rotary flow throws the dust out of the air stream and toward the walls of the collector. In a typical cyclone, the particulate strikes the wall of the collector and falls to a hopper below for collection. Cleaned air is then vented through the top of the collector. While this form of collection can be highly efficient in dealing with large, dense particulate, extremely fine dust lacks the inertia to escape the air stream and is subsequently carried out with the cleaned air. Some high efficiency cyclones like the Aerodyne 'S' Series, use two air streams, to more efficiently separate the dust. The Aerodyne's powerful secondary air stream intercepts the particulate before it contacts the side wall, reducing wear when handling abrasive materials. This secondary air stream also helps to sustain the cyclonic action inside the collector, thereby increasing its efficiency.

 

Filter media dust collectors such as baghouses and cartridge filters use a fine filter media to remove dust from an air stream. The dust-laden air is drawn into the collector where it passes through the filter media and particulate is intercepted. Dust builds up on the filter until it is cleaned or replaced. Cleaned air is then vented out of the collector.

Many manufacturing processes involve circumstances that make it very difficult to rely completely on a baghouse. Heavy dust loading can be a maintenance nightmare for a filter media collector. A rock crushing operation based out of Minnesota realized the benefits of placing a cyclonic dust collector before its baghouse. The enormous amount of rock dust generated in the crushing operation was blinding the bags and causing frequent shutdowns. The decision was made to install a cyclonic dust collector to receive the dust before being sent through the bag house. The cyclone captured the vast majority of the rock dust, leaving only a small amount of fine particulate for the bag house to handle. The cost of the additional equipment was quickly recovered through fewer shutdowns and less frequent bag replacement.

Processes involving high temperature exhaust gas also plague filter media collectors. The hot air temperatures exhausted from foundries, glass making plants, and power plants can burn the filter media used by most baghouses. While high temperature filter bags and cartridge filters are available, they can be an expensive addition and are still not completely immune to the heat. Used as a spark arrestor, a cyclonic dust collector can be placed before a bag house to both reduce the temperature of the air stream and the particulate loading before it enters a final stage filter.

While a mechanical dust collector may not be necessary in every application, the benefits that can be gained from this proven technology are evident. As emission standards become more stringent and process costs continue to rise, any advantage that can be taken should be considered. By comparing process costs such as materials, labor, and downtime with the expense of a cyclone, a decision can be made as to the need for such equipment.

To learn more about the different types of Dust Collection methods please contact our experts at 440-543-7400 or click on the button below to get our whitepaper, Not Your Grandfather's Cyclone. 

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Topics: dust collector, cartridge collector, horizontal cyclone, pre-filter, dust collection system efficiency, maintaining air valves, splitScream Cyclone

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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