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 3^rd 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.

Dust Collection Deathmatch: Baghouse vs. Cartridge

 

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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.

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?

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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.

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Heavy dust loading in the dust collector leads to high maintenance dust collectors.  Since most dust collectors are fabric filters (baghouse, cartridge collectors, shakers, etc.), heavy dust loading will cause/require high frequency of cleaning of the filters.  Most filters are cleaned by injecting high pressure air into the clean side, causing the filters to expand a bit.  This causes dust to fall off the filters.  Filters wear out due to the frequent expanding and contracting.  So the more often you have to clean a filter, the faster the filters will wear out.

Pleated Filters

This is made even worse if the filters are pleated.  Pleated filters have valleys and ridges which increase the surface area available for air to diffuse through the filter.  However, high dust loading can cause the pleated filter valleys to fill up and not properly clean during a cleaning cycle.  This will severely restrict the surface area available for airflow, which will lead to higher velocities through the filters.  A higher velocity increases the chances of dust getting through the filters.  This can cause holes to develop in the filter.  It can also cause dust to plug a pathway through the filter, thereby further restricting airflow.  It can also cause a decrease in removal efficiency.

So if you have high dust loading in your dust collector, it might be beneficial to install a pre-filter to increase filter life and make maintenance much less of a hassle.

Pre-filtering may reduce operating and maintenance costs by extending bag or filter life and improving removal efficiencies. This video discusses five warning signs that your dust collection system needs a pre-filter.

If you prefer this valuable information in white paper form, get our whitepaper, Top 5 Reasons to Use a Cyclone as 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.

To help answer this question, NFPA has released NFPA-652 and 654. A combustible dust is defined as a finely divided combustible particulate solid that presents a flash fire or explosion hazard when suspended in air or the process-specific oxidizing medium over a range of concentrations. Basically, what this means is when the dust is in the air and its concentration is enough to cause a flash fire or propagate a deflagration or explosion if exposed to a spark or heat source, then it’s considered combustible.

Combustible Dust Testing

Unless you know for sure that your dust isn’t combustible, you should send the dust sample to a lab for testing. The lab will provide one of three responses – no reaction, combustible but not propagating, or propagating. 

Usually the lab will initially do a Go/ No-Go test. If the dust doesn’t exhibit combustion, the testing will stop. If it does exhibit combustion, they will then do further tests and provide explosion properties ( Kst and Pmax) of the dust. The Kst tells you how quickly the explosion will propagate, while Pmax tells you the power behind the event.

Common Knowledge about Combustible Dust

1. A combustible dust mixed with non-combustible dust may or may not pass the go / no-go test; therefore, if you have both in a mixture, get a test.
2. Material that may not burn can still be combustible as a dust, unless you know for sure, getting a test is the safe bet.
3. If you have made a process change that changes the composition, relative concentrations, etc. of the dust, then the combustibility of the dust may have changed and a new test should be done.
4. If you have combustible dust in your facility, then a hazard analysis of the area must be done every five years.

Dust Collector FAQ Volume 1

To make life easier, we have put together some common questions we get asked along with answers and explanations. Have a look.

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.

With the release of NFPA 652 and 654, manufacturers that create dust in their processes are required to conduct a Dust Hazard Analysis if the dust is explosive.  NFPA 652 requires this to be done by 9/7/2018 but NFPA 654 has extended it 5 years.  The Dust Hazard Analysis is retroactive, so all manufacturers are required, no one is grandfathered in.

The DHA should be as simple or as complex as the process and needs to be documented for OSHA.  The main purpose of the DHA is to educate the owner and operators on the true hazards and dangers they are facing with their dust, and to make sure they take the proper precautions with it.  The DHA is there as a tool to prevent loss of life, equipment, production time, and capital.

Aerodyne will be addressing the DHA further in future Blogs!  Stay tuned.