When considering the right dust collection solution for your facility, we’ve previously mentioned 5 factors that need to be considered:
Dust Properties – Learn the dust properties you need to be aware of to help you find the right filter media and type of dust collector.
Volume – Understand key variables for measuring volume or airflow requirements in your work environment in order to size your collector properly.
Air-to-Cloth Ratio – Learn why air to cloth ratio is important and how to find the right air-to-cloth ratio for your operation.
Dust Collector Styles – Learn about three most common dust collectors, their advantages and disadvantages.
Low Maintenance Design Features – Learn important dust collector design features that will help you save time and money in long term maintenance expenses.
When sizing a new dust collector, these factors, along with understanding the importance of can velocity, will allow you to avoid unnecessary difficulties that would prevent your system from performing at peak efficiency.
What is Can Velocity in a Dust Collection System?
Can velocity is the speed at which air moves from low in the baghouse to high. The higher the can velocity, the faster air moves up in the system. The right can velocity for your dust collection system will be based upon your application and the density of your product. At US Air Filtration our engineers calculate your can velocity based on a few different factors.
The different dust characteristics and operating factors that help us understand can velocity are:
Particle size
Bulk Density
Agglomerating/non-agglomerating (stickiness of the material)
Loading rates
How to Calculate Can Velocity for a Dust Collector
In simple terms, the calculation is based on the area of the bottom of your dust collector’s filter bags. For example, if you have a dust collection system with 200 filter bags the calculation is the following:
Graphic Above: Dust collector housing ➖ area of the round bottom of the bags (qty 200) ➗ divided by volume
Impacts of Improper Can Velocity in a Dust Collection System
Low Can Velocity
Low can velocity can lower air speed. If left for an extended period of time, dust can begin to accumulate inside your duct work. This build-up of dust work can cause a decrease in airflow or suction at your pick-up points, thereby resulting in an insufficient performing dust collection system.
High Can Velocity
High can velocity can cause higher differential pressure and an increase in cleaning cycles of the pulse-jet cleaning system. This can result in filter bag abrasion caused by too much airflow through the dust collector housing and increased energy costs.
A dust collection system with a high can velocity may filter as you expect at first, but as time goes on, dust will continue to cover the filter bags. The dust collection system will not be able to drop the dust off the bag, therefore the permeability per bag will decrease, and you will lose airflow.
How To Solve High Can Velocity
Solving for an excessively high can velocity can be tricky. We recommend working with a U.S. Air Filtration engineer to help determine what the right solution would be for your particular problem and dust collection needs. In general, some of the solutions can include:
Industrial dust collection suppliers generally quote systems based on air to cloth ratios, but it’s important to keep in mind that air to cloth ratio and can velocity are related. Can velocity is a variable to consider depending on what type of material you have. For example, if your application includes very light material, we recommend paying close attention to the quotes you’re receiving. If one potential supplier has quoted you with a low inlet, high can velocity, and a price that is significantly less, then that dust collection system will have higher differential pressure, an increase in cleaning cycles, too much airflow through the dust collector housing causing filter abrasion, and ultimately be unable to perform as it was intended to.
Considering all the components involved in choosing the right dust collection system can be an overwhelming process. While it’s important to understand the impact of can velocity on both performance and price, our ultimate goal at U.S. Air FIltration is to provide you with the full service of designing and engineering the right dust collection system that will meet your specific needs and requirements. When you work with U.S. Air Filtration engineers for your next dust collection project, they will ensure you have the right air to cloth ratio and can velocity that will allow your system to perform safely, efficiently, and reliably for many years to come.
If you’re just getting started, you can request a free project consultation with a dust collector equipment engineer here. Get assistance with can velocity, CFM, volume, filter media, design spec recommendations, and more.
Industrial dust collection systems are vital to maintaining efficient plant production and ideal working conditions. Dust collection systems designed to filter airborne dust and debris can range from small bin vents to complex and customized turnkey baghouse systems. There are several factors that play a role when choosing the right dust collection system for your facility. These factors, along with assessing up-front and long term costs of baghouse ownership will help guide you to the dust collector that can handle your filtration needs, while offering long-term cost-saving features.
In a new dust collection project you have two types of costs; up-front and long-term. Up-front costs play a major role, but equally important are long-term operational costs which can add up significantly over time.
Upfront Costs of Baghouse Ownership
Cost of engineering and design
Fabrication
Shipping costs
Installation
Baghouse system and parts
Long Term Costs of Baghouse Ownership
Stack testing: The frequency and requirements for stack testing will be determined by your state or local air pollution office. For example, if you are located in California you would refer to the AQMD office for the rules and regulations your facility needs to meet.
Energy Usage: This includes the energy costs to run the dust collector itself and all of its components. The dust collector component to consume the largest amount of power from a baghouse would be the fan, and fans can consume up 95% of the baghouse energy. Other costs include the compressed air being used to clean filters.
Cost Saving Tip: On-Demand cleaning improves dust collector performance while reducing energy consumption and labor costs. Learn more about on-demand cleaning for Pulse-Jet technology in this article here.
Replacement Parts: The 5 most commonly replaced parts on a dust collector are filters, pulse valves, timer boards, solenoids, and diaphragm kits. Beyond the replacement parts on the dust collector itself, you will also want to consider the replacement costs for the dust collector’s accessories. This may include:
Fan: With proper maintenance of the fan’s belts and bearing, a fan can typically last as long as the baghouse itself. For free access to a fan maintenance guide, head over to our PDF here.
Screw Conveyors: Being on the dirty side of a dust collection system, a screw conveyor receives a lot of wear and tear. This is the reason why a screw conveyor may wear out before the lifespan of a baghouse ends.
Duct Work: Abrasive atmosphere or dust can contribute to the erosion of ductwork.
Cost Saving Tip: Understanding the signs of a worn out dust collector part can help you identify any issues before they become larger problems. Learn more about the common warning signs in our video here.
Shipping: These are costs associated with shipping replacement parts.
Cost Saving Tip: Eliminate price increases and delayed lead times with automatic parts delivery that you have full control over. Get answers to the most frequently asked questions about parts delivery here.
On-Going Maintenance: One of the tips to maximizing the life of a dust collection system is implementing a preventative maintenance plan. Depending on your system, preventative maintenance checks can be weekly, monthly, semi-annual and annual. For access to a comprehensive dust collector maintenance guide with free PDF download, visit our article here.
Beyond preventative maintenance, there is a 22-point inspection which can ensure your system is running at its peak performance. To get more information on a 22-point inspection and what it includes, check out this article here.
Waste Disposal: Costs associated with removing and disposing of dust and debris.
Labor for Change-Out’s: There are multiple factors that drive the cost of labor for a change-out. Some of these include travel, number of filters being replaced, the environment of the dust collector, and more. When you choose to outsource this service to experts, it may include:
Repair or replace damaged solenoids, valves, or diaphragm kits
Any other repairs or troubleshooting needed on a baghouse – for example, vibration issues with a system after a filter change
If you are looking for more information on dust collection services and the commonly asked questions needed to determine cost, get full insight with this guide.
Highest Long Term Costs of Baghouse Ownership
Replacing dust collector parts like the filter cartridges, filter bags, the delivery cost for those replacement parts, the labor costs to switch out or maintain those parts, and maintaining inventory will be some of the highest long-term costs you incur. Filter replacements will be your highest maintenance item moving forward because, depending on your application, the lifespan of a filter can be anywhere from 1 year to 5 years.
Lifespan of a Baghouse
A properly maintenanced dust collection system in a non-abrasive environment can typically last around 20 years. On the other hand, the lifespan of a dust collection system in an abrasive environment is only between 5-10 years. An example of an abrasive environment can include a dust collector sitting outside of a plant, near the beach. In this scenario, you may start to see rust on the housing within 5 years.
How to Extend the Life of a Baghouse
We understand that getting the most out of your dust collection system is important. Below we are sharing our top tips that can help extend the life of your baghouse.
Benefits that Extend the Life of a U.S. Air Filtration Dust Collection System
To help further maximize the lifespan of a dust collection system U.S. Air Filtration offers the following benefits.
U.S. Air Filtration primes the inside walls of your dust collection system to add a layer of protection
Additional epoxy paint options can be added if required (additional cost varies depending on system size, paint, etc.). For example, a cement barge loading or transferring cement that may require a marine grade epoxy on their dust collection system.
U.S. Air Filtration fabricates our dust collection systems in 10 or 12 gauge, while other suppliers may provide a thinner 14 gauge to cut costs
Where applicable, heavier duty equipment may be provided as an option to lengthen the accessory’s lifespan. For example, a 5HP drive for a 20 foot screw conveyor instead of the typical 2 HP.
Dust Collection Cost-Cutting Steps to Avoid
If purchasing decisions are made solely based on the cost of equipment and not quality or application, you could end up spending less up front, but increasingly more over time. Some of the shortcuts to avoid on the front end are:
Improper Air-to Cloth Ratio: Air-to-cloth ratios may cut up-front costs but they also cut you short on static pressure. For example, baghouses with a 10:1 air-to-cloth ratio will give you inconsistent suction at your pick-up points, resulting in clogged filters and more frequent change outs. Ultimately you’re going to be paying more in the long run than you would have if a proper air-to-cloth ratio was considered. To get a better understanding of the importance of air-to cloth-ratio or how to calculate it, access our latest video here.
Cheap Baghouse Material: Avoid suppliers that fabricate their systems with the bare minimum materials and construction.
Summary
At U.S. Air Filtration we do not have a cookie cutter approach. Every dust collection project is specific to the customer. Therefore, we recommend working with an engineer to customize a dust collection system that will meet the unique characteristics and needs of your facility. This is the best approach to getting the long-term performance you need out of a dust collector.
There are two common approaches for using cyclone dust collectors, as a stand-alone system or as a pre-filtration unit paired with a larger dust collector. This article includes information on:
How cyclones work
The benefits and disadvantages of a standalone cyclone
Understanding these variables can help you identify whether a standalone cyclone system is best for your application or if you need to pair your cyclone with a larger dust collection system.
How Does a Cyclone Dust Collector Work?
Cyclone dust collectors are small-scale stand-alone units that work to remove large dust particulates from the air using centrifugal force. The filtration process starts with dirty air being drawn into the cyclone dust collection system at a high speed. This high-speed motion works as a controlled “hurricane” inside of the cyclone. The “hurricane” motion allows larger particles to be pushed out and up against the cyclone walls. Then once the dirty air hits the walls of a cyclone, momentum slows down, which is enough to permit larger particles to drop out of the airstream and into a hopper beneath.
Dust Characteristics, Capacity, CFM, and Cyclone Dust Collectors
Understanding your Dust characteristics is the first step to understanding whether you need a baghouse, cyclone or both?
Cyclone dust collectors are ideal for applications dealing with large, coarse dust particulate. If your application contains a mixture of large and small dust particulate, you’ll likely need tofilter larger dust particulate out first with a cyclone and then direct the remaining gas stream to a larger baghouse that uses filters to handle finer particulate. This two-step filtration process helps prevent large particulate (e.g., wood chips) from creating unnecessary wear and tear on baghouse filters.
Beyond dust characteristics, dust loading rates and CFM are factors when considering which dust collection system is best for a specific application. Because cyclone dust collectors are small-scale units, their capacity to handle dust particulate is finite. General dust loading rates can be between a 5-to-30-gallon drum. In terms of CFM, most cyclones operate anywhere around 1000 CFM or below.
Common Applications for Cyclone Dust Collectors
Applications for Stand-Alone Cyclones:
Woodworking applications with only large dust particulate
Agricultural applications with only large dust particulate
Applications for a Baghouse or Baghouse and Cyclone System:
Woodworking (all)
Agricultural (all)
Mining & Minerals
Recycling
Pharmaceuticals
Paper Products
Chemicals
Rubber Plants
Food Manufacturing
Bulk Powder
Industrial Equipment and Machinery
And More!
Advantages and Disadvantages of a Cyclone Dust Collector
Cyclone dust collectors are designed as a simple steel structure with no moving parts or filters. Because of this simplicity, the main advantages and disadvantages are:
Advantages of a Cyclone:
Low up-front investment. There are a wide variety of models, but generally you can find a cyclone dust collection system ranges anywhere from $500-$3000.
Long-term cost savings on maintenance and repair
Paired with a larger baghouse, can increase the efficiency and life of filter bags or cartridges
Disadvantages of a Cyclone:
Low dust loading rates
Limited CFM capabilities
Low efficiency at capturing fine particulate
Unable to process sticky materials
Application use is limited
Benefits of a Cyclone with a Baghouse Dust Collection System
In specific cases, an engineer may determine that your plant can benefit from pairing a cyclone with a larger dust collection system. Typically, processes that have a mix of large and small particulate are the ideal candidates for this type of setup.
A cyclone could be implemented as a pre-filtration system to eliminate any large, coarse particles that could damage a dust collector’s filter bags or cartridges further downstream. The result is an increase in the performance of a dust collection system and the service life of the baghouse filters. In certain cases, cyclones can also help to reduce dust loading into a baghouse with a high inlet entry. This method reduces internal velocities (e.g., can velocity) resulting in improved efficiency and increased filter life.
To determine whether your application would benefit from a combination cyclone and larger dust collection system, some questions you may be asked include:
What’s the size of your particulate? Is it big? Small? Mixed?
How much dust are you filtering out in a given work shift?
Could your dust collection design incorporate an end inlet as an alternative? While there is no cyclonic action with an end inlet, the attributes are similar. An end inlet helps bring in the dust high, but as it hits a baffle, it redirects the air directly downward. In this scenario, heavy particulate hits the baffle, then slows down and drops out. Then rest of the air is kicked down below the bag, allowing your system to still have can velocity. The disadvantage to an end inlet is these types of baghouses tend to be considerably larger because there must be space for air to hit the baffle.
Even in similar industries, plants will have different requirements and variables from one another that will determine the right dust collection solution. To get beyond the basics, we recommend speaking to an engineer who can help with your specific application and needs.
Conclusion
To summarize, cyclones are limited in their capabilities. In certain conditions you could add a cyclone to be helpful and reduce dust loading on larger systems, but cyclones alone are not typically adequate for most industrial applications.At U.S. Air Filtration our engineers can help determine if the dust collection system you’re looking for would benefit from adding a cyclone. Our goal is to do what we can do to help save you costs, while also ensuring we are designing a solution that will perform long term.
A critical part of the dust collection design process is where to position your baghouse inlet. The purpose of the baghouse inlet is to draw dirty, dust laden air into the system so the air can be filtered. In this article, we will focus on the design factors that help determine a system’s inlet placement (high versus low), can velocity, and the advantages of a high inlet versus a low inlet baghouse.
Dust Collection System Design Factors
When designing a dust collection system, we consider your dust properties and the characteristics of your work environment carefully to identify the best solution. Below are the five most critical dust collection design elements.
During the design process, we consider two primary characteristics that influence baghouse inlet placement:
The amount of dust you are bringing into the collector
The heaviness of the dust
When you have a large amount of dust and that dust is heavy, a dust collection system may benefit more from a low inlet design. When heavy dust enters the unit at the bottom of the system, the natural force of gravity will pull the dust down. Conversely when you have light to medium dust loading and very light dust, a dust collection with a high inlet design would typically be best.
However, even in similar environments the dust loads, work environment, and space can vary drastically. Our best recommendation is to work closely with your U.S. Air Filtration equipment specialist. Understanding all the details and nuances to your specific project will allow us to make the best design recommendations.
Can Velocity and Dust Collection Design
Can velocity is the speed at which air moves from low in the baghouse to high. The higher the can velocity, the faster air moves up in the system. We calculate can velocity based on your CFM, the size of the collector, and your space restrictions.
During the design process, your equipment specialist can help determine if there will be a high enough can velocity that would require a high inlet. A high inlet will eliminate or counter can velocity. This way, dust can drop or if the dust is heavy enough, the dust will overcome upward air movement and drop out without issue.
CFM, space restrictions, and dust loads are all straightforward questions. But depending on the answers provided there can be different results. Here are two different scenarios that could occur during the design process that require two different inlets.
Baghouse Inlet Scenario 1:
No design preference for the inlet.
No space issues
In this case, it’s possible for a customer to have a system that’s designed to hold 700 filter bags, 8’ in length, with a low inlet. This scenario is possible with just about any type of dust. All that is needed to drive that air to cloth ratio down as low as possible, is to eliminate as much can velocity as you can. As a result, your dust collection system will work as intended with a low inlet design
Baghouse Inlet Scenario 2:
No design preference for the inlet.
Yes, there are space constraints.
In this example, if there is only a 15’ by 15’ space to install a dust collection system, the system must be taller and require longer filter bags of 12’ to adequately handle the dust load. filter bag. By design, there will be a much higher can velocity even though the same air to cloth ratio is being used. This is because the filter bag is longer, the dust collector is thinner, more vertical rather than wider, and shorter. These factors all increase can velocity. Because the can velocity is higher, a high inlet would be required to allow better dust dropout.
High versus Low Inlet Dust Collector Design Advantages
When considering a high versus low inlet for your dust collection system, there are certain design advantages that are considered based on dust type and application. There are additional costs for a high inlet baghouse. If your project will allow for a low inlet design, then that’s the route we recommend. Our goal is to help you avoid spending more money than necessary both upfront and in long term maintenance costs.
However, in certain situations it may be worth investing in a high inlet. These situations include:
When you are worried about the dust not dropping out of the airstream
If you are afraid you are going to lose suction over time
In these cases, it may be worth spending the extra money to design a dust collection system with a high inlet, to avoid these issues. You will also have the added benefit of avoiding additional maintenance problems down the road.
Additional Baghouse Inlet Options
What if your application has light dust, but high dust loading? An additional option in this case would be an end inlet. This helps bring in the dust in high, but as it hits a baffle, it redirects the air directly downward. In this scenario, heavy part particulate hits the baffle, then slow down, and drop out. Then it kicks the rest of the air down below the bag, so you still have can velocity. However, we reduce the amount of dust in the airstream so much that can velocity is not as much of a concern as if it was just a standard low inlet baghouse. The disadvantage to an end inlet is those baghouses tend to be considerably larger because you must have space for that air to hit the baffle.
The Design Process with U.S. Air Filtration
At U.S. Air Filtration, our V.P. of Engineering, generally recommends a low hopper entry or side entry inlet baghouse with a full blast height plate/drop-out box plenum, if the particulate from the process is highly abrasive and/or has a bulk density of greater than 70 lbs./CF. (I.e., Sand, silica, glass, etc.) If you have questions regarding this exception, please contact U.S. Air Filtration’s engineering department for further explanation.
At U.S. Air Filtration, we understand that a dust collection project may just be one piece of a larger project for you. Our engineers are here to help solve your concerns and design a solution that best fits your application and facility. If you need to speak with an equipment specialist, please feel free to contact us at 888-221-0312 or email [email protected]. If you’re just starting your dust collection project, access our “Dust Collector Purchasing” article for more information on design considerations, airflow, air-to-cloth ratio, and more.
CFM is a measurement of airflow related to air conditioning, heating and ventilation environments. In dust collection applications CFM measures the amount of air per minute that can be moved from a space.
If you’re not familiar with how to calculate dust collection CFM, the process can be intimidating. In this article we will help you understand our approach to calculating CFM requirements for you. Along with the questions you should be asking your dust collection engineering firm to identify the optimal solution for your plant.
Dust Collection CFM Questions to Consider
Where is your dust being created?
Are you using taps or hoods at the points of dust creation?
One of the first questions we ask is, “Where is your dust being created?” This allows us to understand where your pick-up points are, and how many of those need to factor in when calculating your CFM.
Methods of Dust Collection
Once we understand where the dust is being created, then the next question becomes, “What’s the best way to collect the dust at that dust creation point?” Three common methods are:
Tap
Hood
Articulating Arm
Many facilities include source taps at every machine. If there are no taps, then a hood or a smaller pickup point can be added. For example, a hood can be added above a table to capture dust if there is a need to constantly maneuver around the table.
If there is movement happening around the machine in different ways (e.g., leaning over a machine) then there may be a need for an articulating arm. An articulating arm allows a way for the hood or pick up duct to be as close as possible to the actual creation of the dust. As U.S. Air Filtration helps you calculate the right CFM, we will work together with you to gather these details machine by machine.
What’s Needed to Calculate CFM?
You may not know the CFM you need, but here are the things you can provide that will allow us to help solve that for you.
How close can we get to the machine?
For example, if the machine has a six-inch tap, then we would know that would require a six-inch duct. Generally, when the machine is designed, your pickup points are also designed with the intention to efficiently capture dust.
Blueprint of your facility or a roughly drawn layout
This helps us understand the distances between the machines, walls, and where the dust collection system will be placed.
Photos of your machines. This helps us identify if you are using taps or hoods.
Tap
If there are no taps, how are people using the machine?
Is the machine stationary?
Does someone need access 360 degrees around the machine?
Hood
If there are no hoods, what is the size of the machine or table that’s creating dust? This helps us properly size a hood and with those dimensions we can look at velocity at the hood.
Then, depending on the weight of the dust, we get a better understanding of the specific velocity needed to move the dust and the duct size that’s required. These two factors together can help us get to the right CFM for your dust collection project.
Dust Collection Source Capture versus Room Capture
In the case of a grinding application, you may do all your grinding in one room and want to ventilate the entire room itself.
While the initial calculations and process to ventilate one room may seem easier, it’s not necessarily the best in terms of cost. Our recommendation is to get as close as you can get to the source of the dust, which allows you to move less air. This can mean a smaller system, which can lower the price tag of your project while also capturing dust more efficiently.
For an everyday example, let’s say you have dust all over your kitchen floor and you don’t want to vacuum every square inch of it. Then your option would be to try and suck the dust up through a hood. That requires you to pull a large amount of air very quickly, which in turn requires much greater force from the fan to capture the dust. In contrast to that, if you have a vacuum and a hose, then you can pick up everything closely using a very small amount of air and suction requirements.
While it may be tempting to “just ventilate the room”, keep in mind that every CFM comes with a price tag. Moving 100,000 CFM versus 10,000 CFM is going to be more costly. The details that go into calculating your CFM may be cumbersome at first, but it will save you from spending a considerable sum of money in the long run.
Negative Impacts of Miscalculating CFM
When designing a dust collection system, it’s best to err on the high side of CFM rather than the lower side. It’s very difficult is to make a dust collection system larger once it’s in place. It’s much easier, if necessary, to damper the fan down or add a smaller fan.
Correcting for a larger than needed dust collection system involves adding more filter media. Upfront costs are slightly higher, but your system will work well, and you’ll be able to remove dust out of the way as you intended. The reverse isn’t true. If your system is too small, it’s very difficult to add filter media. Getting the dust out of your facility will always be an uphill battle. So, to reiterate when in doubt error on the high side.
If you underestimate CFM, you won’t capture the dust that you need to capture.
The system will not work the way it was designed. Therefore, you will spend a large sum of money on maintenance expenses due to increased wear and tear..
If you overestimate CFM, the dust collection system will work just fine, but long term you will pay 20%-30% more for a system.
Advantages of Working with USAF
One of the advantages of working with U.S. Air Filtration is that we have a team of engineers with over 40 years dust collection experience who can gather the details you provide and calculate the numbers to get you to the right CFM.
Calculating CFM and designing a system is a complex engineering process. We do all the leg work for you, so you don’t have to.
If you would like to speak to an engineer about your specific project, contact us at 888-221-0312 or email [email protected]
Download the free PDF version of this Dust Collector Purchasing Guide here.
Our dust collector purchasing guide will help you identify the right dust collection system that will perform safely, efficiently, and reliably for many years to come. Identifying the right components and needs for your next dust collector can be an overwhelming process. Factors to consider include:
5 Things to Consider When Purchasing a Dust Collector
Dust Properties – Learn the dust properties you need to be aware of to help you find the right filter media and type of dust collector.
Volume – Understand key variables for measuring volume or airflow requirements in your work environment in order to size your collector properly.
Air-to-Cloth Ratio – Learn why air to cloth ratio is important and how to find the right air-to-cloth ratio for your operation.
Dust Collector Styles – Learn about three most common dust collectors, their advantages and disadvantages.
Low Maintenance Design Features – Learn important dust collector design features that will help you save time and money in long term maintenance expenses.
At the end of this dust collector purchasing guide, there are also additional resources that provide more details about combustible dust considerations and on demand cleaning.
Dust Properties and Your Work Environment
Do you know your dust? Consider your dust properties and characteristics of your work environment carefully to identify the best dust collection solution.
Dust Properties to Consider:
Size – What is the size of the dust particles being filtered; fine or large?
Density – Is the dust low in density like wood dust or heavy in density like fine steel dust?
Chemistry – Will you be filtering any abrasive dust? Corrosive dust?
Temperature – Are you operating in a high heat environment? What is the operating or maximum temperature at your facility?
Moisture – Is moisture or oil present in the dust?
Knowing your dust properties is the first step to help you determine the type of dust collector that is best suited for your unique application.
Your Work Environment
The next step to finding the right dust collection solution is to consider your space constraints, emissions requirements and temperature of your airstream.
Space Constraints
Dust collectors vary in height, width and depth depending on the application and the amount of dust being captured. Take note of any height or space restrictions in the work environment and take measurements of the space allotted for your collector along with the space available around the collector. Many dust collectors are top load which means you will need to allow space above the collector to replace and service the collector from the top of the unit.
Emissions Requirements
Depending on your application, your dust collector may require a permit with specific emissions requirements. These emissions requirements vary by state and are expressed as an efficiency percentage for cartridge collectors or an emission limit (e.g. lbs/hr or gr/dscf) for baghouses.
Temperature of the Environment
The temperature of the airstream will determine what type of filter media is required and will affect fan size. Temperatures greater than 260 degrees will require special filter media and changes to the dust collector fan. If the unit will be outside in a cold/extreme climate you will need to consider insulating the unit as well.
Understanding Volume or Airflow Requirements
Calculating Your Airflow
After considering your dust properties, the next step in dust collector purchasing is our airflow or volume requirements. Calculating your airflow correctly is critical to the long term health of your collector so your system will be efficient at capturing dust.
Why is Volume Important?
If the volume of the system is too low, your system will not capture the dust effectively which can impact production and air quality. If the volume of your system is too high, your energy consumption costs will be higher and you may disrupt the process of your application.
How is Volume (Cubic Feet Per Minute) Measured?
Dust collector volume is measured in cubic feet per minute or CFM. CFM is a measurement of airflow especially related to air conditioning, heating and ventilation environments like those requiring dust collection. In dust collector applications CFM measures the amount of air per minute that can be moved from a space.
Variables to Consider
Work environments vary dramatically from one another based on several variables, and even very similar environments can require vastly different volume. To determine the right volume capabilities for your new dust collector, consider some of the following variables carefully.
How are you collecting dust?
What is the size of the duct being used to collect the dust?
Cubic feet of the work environment
Air-to-Cloth-Ratio
Dust collector air-to-cloth ratio is a critical measure to ensure your air filtration system is performing efficiently.
What is Air-to-Cloth Ratio?
Air-to-cloth ratio, also known as air-to-media, is defined as a measurement of the amount of air passing through one square foot of filler media. Generally the lower your air-to-cloth ratio, the more effectively your system removes dust from the work environment. If you are operating at a higher air-to-cloth ratio, one of the common issues you may encounter is a decrease in suction. This is because a large amount of dust laden air is filtered by an insufficient amount of filter media. The dust cake on the bag builds up too quickly; resulting in a decrease in air flow through the filters and suction at pickup points.
How to Select or Calculate Air-to-Cloth Ratio
If you’re sizing a new cartridge collector system and know what type of dust will be filtered and the air volume needed to properly ventilate the area or pickup points. Our Air-to-Cloth Guide below is a good place to start. The guide gives you a general recommendation on the air-to-cloth ratio for several different applications. To find the dust collector suited to your dust and air volume requirements simply:
Divide air volume of system by air-to-cloth ratio to get the total amount of filter area needed into the system.
Divide the total filter area by the filter area per filter to determine how many filters are needed in the dust collector.
Find the dust collector model that best fits your application by number of filters
and type of dust collector.
To calculate air-to-cloth ratio in your existing system, calculate the volume of air (CFM) and divide that number by the total filter area within your dust collector. For example, a sixteen filter cartridge collector pulling 7,000 CFM would have a 3.65:1 airto-cloth ratio (7000 CFM / 16 filters x 120 ft2 per filter). Or in the case of a baghouse, a hundred filter baghouse pulling 10,000 CFM would have a 6.37:1 air-to-cloth ratio (10,000 CFM / 100 filters x 15.70 ft2 per filter). Environments with a large ventilation area or more pick up points require a higher air volume (CFM) to provide adequate suction which means more filter media to keep a similar air-to-cloth ratio.
Why is selecting the right Air-to-Cloth ratio important?
Allows your dust collection system to perform at peak efficiency
What are the negative effects of improper Air-to-Cloth ratio?
Poor venting which causes damage to equipment
High pressure drops in differential pressure
Impacts your air velocity
Excessive use of compressed air
Dangers of an Undersized Dust Collector
Choosing a collector that is too small can cost you in long term maintenance costs. Some of the biggest problems we see people run into with an inappropriately sized dust collector are:
To avoid the dangers of an undersized dust collector consider both CFM and air-to-cloth ratio carefully when designing your new unit.
Dust Collector Styles
Baghouse Styles
Baghouses are ideally suited for large volume applications with airflow exceeding 1,000 CFM or when high temperature applications are above 375 degrees. In these environments, a baghouse will handle and most efficiently filter your dust laden air. There are several types or styles of baghouses available. Once you understand your dust properties, volume, and air-to-cloth ratio, you can determine the right baghouse style for your facility. Here is a summary of the pros and cons of the three most common baghouse styles: pulse jet baghouse, reverse air, or shaker style.
Pulse Jet Baghouse
Pros
Cons
Bags cleaned continuously while unit is in operation
Requires compressed air
Easy to maintain, low maintenance cost
Not ideal for high moisture applications (+20%)
Flexible Sizing and Configuration
Requires filter cages
Reverse Air Baghouse
Pros
Cons
Low maintenance
Needs to be cleaned often
Gentle cleaning which allows for longer bag life
Residual dust build up is hard to remove
Units are typically compartmentalized into sections which allows them to be maintained without shutting down the entire baghouse
Filter bags are expensive compared to Pulse Jet bags
Bags are typically custom made and not available in stock for quick shipment
Shaker Baghouse
Pros
Cons
Very simple to operate
Limited filter media options
Low initial investment cost
Not space efficient (takes up a large area)
Filters cleaned via shaker mechanism
Not suited for high dust loads
Bags are typically custom made and not available in stock for quick shipment
What’s the Right Type of Pulse Jet Dust Collector?
The three most common pulse jet dust collection systems are baghouses, cartridge collectors, and bin vents. Below is an overview of each type of pulse jet system and common applications for each:
Baghouses
Baghouses are typically the largest of the three types of dust collectors. They are well suited for large volume and high temperature applications. Baghouses are perform well for applications with high dust loads of more one 55 gallon a drum per day. The most common applications that use baghouses include:
Wood
Mining
Asphalt
Foundries
Cement
Cartridge Collector
Cartridge Dust Collectors are compact and very modular in design. These are best suited for applications with the following characteristics:
Moderate or low dust (collecting less than one 55 gallon drum per day)
High efficiency filtration requirements
Space restraints or small footprint requirements
Possibility of future plant expansion
The most common applications for cartridge collectors include:
Welding
Grinding
Laser/Plasma Cutting
Bulk Powder Processing
Listed here is a baghouse and cartridge collector comparison chart to help you determine which option may be best suited for your application.
Bin vents are usually used in applications where you are moving product from one location to another. Like a cartridge collector, bin vents are also compact, and designed for easy change-outs. They are designed to efficiently vent silos and tanks while minimizing product loss. Bin vents are frequently used in the following applications:
Cement
Agriculture
Tank Loading
Conveyor Belt
Low Maintenance Design Features
To avoid the hassle of excessive and costly change-outs and maintenance consider important dust collector design features that will help you lower your long term maintenance and energy costs.
Listed below are some of the easy maintenance design features your dust collector should include.
Dust Collector Design Features for Easy Maintenance
Standard filter sizes to ensure product availability and competitive prices
Multiple filter options for a variety of applications
Additional Resources for Dust Collector Purchasing
How to Prevent a Dust Collector Explosion
If you are dealing with combustible dust, you’ll need to implement a preventive maintenance plan, which will help you avoid a serious dust collector emergency.
What is combustible dust?
Combustible dust can be defined as any fine material that has the ability to catch fire and explode when it’s mixed with the proper concentration of air.
When can combustible dust create an explosion?
When the right conditions are in place, combustible dust can become hazardous and create an
explosion. Dust can collect on multiple surfaces in a facility (e.g. ducts, crevices, dust collectors, equipment, etc.), and once this buildup of dust mixes with the right conditions, it only takes a small ignition source to create a significant explosion. There are even scenarios in which combustible dust can self-ignite. This usually results from static that builds up as the particulates rub against one another.
Who does it affect?
Combustible dust effects a wide variety of industries such agriculture, metalworking, mining, chemicals, plastics, pharmaceuticals, etc. Industries that are susceptible to combustible dust are regulated by OSHA standards and NFPA guidelines.
How can I prevent a dust collector fire?
Now that you know what conditions required for combustible dust, when it can happen, and who it effects, how do you limit or prevent a serious explosion from happening? Your best plan of action is going to include steps that are proactive instead of reactive. Here are the proactive steps you can take:
OSHA Standards: Ensure you are meeting OSHA’s set of standards regarding
combustible dust. Industries that are susceptible to combustible dust are regulated
by OSHA standards when you implement OSHA’s set of standards, you are
creating a safe working environment, avoiding property and economic loss from an
explosion, and avoiding regulatory fines.
NFPA Guidelines: Make sure you are meeting codes outlined by the NFPA (National Fire Protection Agency). The NFPA publishes a list of guidelines that will
help you minimize injury or death from combustible dust. The following codes are
related to the most combustible types of dust (e.g. sugar, wood, fine aluminum):
664, Standard for the Prevention of Fires and Explosions in Wood Processing and
Woodworking Facilities
484, Standard for Combustible Metals
61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and
Food Processing Facilities
Explosion Vents: Installing an explosion vent on your dust collector is one strategy
that can minimize damage to your equipment and harm to employees should an
explosion happen. The purpose is to relieve pressure in the dust collector caused
by an explosion. Once the activation pressure is exceeded the vent(s) open safely
relieving pressure.
Explosion Latches: Latches operate under the same concept as explosion vents.
Latches provide venting in the event of an internal explosion.
Dust Collector Purchasing Summary
Selecting and pricing out a dust collection system involves careful consideration of each of the variables outlined above. Proper attention to these items is critical to ensuring your dust collector performs efficiently for many years to come and creates a clean, safe work environment for plant operators. Each dust collection application is unique, and it is possible that applications with very similar product characteristics or volume requirements may require a system that is vastly different due to the number of variables to consider. To help you engineer and select the correct system for your facility, consult with a dust collection engineering and manufacturing company with extensive experience designing systems for diverse applications.
If you have further questions unique to your application or would like to speak with an engineer, give us a call at 888-221-0312 or email [email protected]
Dust Collector Sizing Quiz
Would you like to get a price range and a recommended cartridge collector? Simply complete this dust collector sizing calculator and you’ll immediately receive an email with your recommended unit along with a price range for the unit. A dedicated account manager will also contact you within 24 hours to assist in finding the right solution.
The right baghouse dust removal method can help minimize problems that arise due to dust build up in your hopper.
A hopper is designed to be temporary storage for your discharge. What happens if you have excessive dust build up in your hopper? This can result in your air flow being blocked off and would cause a loss of suction throughout the dust collection system. This can also become a hazard because it’s more opportunity for combustible dusts to create a dangerous explosion. The right dust removal method for your application can help you avoid these issues.
Key Components
The best method of dust removal from your hopper is dependent on some of the following components:
What are the characteristics of your dust? For example, hazardous or non-hazardous?
What are the loading rates of your dust?
Baghouse Dust Removal Methods
Enclosed Box
A simple pipe system funneling dust into an enclosed box, placed underneath your hopper, is one dust removal option. Your maintenance team would be required to monitor and empty the box once capacity has been reached. Prompt removal of dust build up in your enclosed box helps prevent backup or an overflow of the box itself. Non hazardous dust and light dust loads typically use enclosed boxes.
Drum or Bag
A removable drum or bag can be a simple and easy solution to collecting and disposing dust. Once a drum or bag fills up, maintenance simply removes it by hand or forklift. Once empty, the drum or bag can then be put back into its place. This is ideal for non toxic dusts that you can easily handle.
Rotary Valve
Rotary valves (also known as airlocks, rotary feeders, or airlock feeders) help transition material from a dust collector to a drum or bin. It seals a pressurized system against loss of air and pressure. This minimizes product loss during processing. Dust collection, pneumatic conveying, mixing, weighing, feeding, and blending use rotary valves. Larger baghouse systems with over 10,000 CFM can also use rotary valves.
Screw Conveyor for Baghouse Dust Collectors
Large baghouses with heavy dust loads typically use screw conveyors. The screw conveyer would transport dust away from the collector, then send it to a designated disposal area. This is ideal for hazardous or reused materials. Agriculture, mining, foundries, wood production, and chemicals are applications that use screw conveyors.
Would you like to learn more about design considerations for a new dust collection system? For more information, download our dust collector purchasing guide.
Before we dig into the differences between some of the baghouse styles, you need to consider your dust properties and air-to-cloth ratio. Baghouses are ideally suited for large volume applications with airflow exceeding 1,000 CFM or when high temperature applications are above 375 degrees. In these environments, a baghouse will handle and most efficiently filter your dust laden air.
There are three main baghouses styles (e.g. shaker, reverse, and pulse-jet) that are commonly used in most industrial processing and manufacturing applications. Here’s a brief overview on the pros and cons of each to help guide you in identifying the right option for your work environment.
Pulse Jet Baghouse
Pros:
Cons:
Constantly cleaned so there is minimal dust build up in the dust collector
Requires dry compressed air
Space Efficient
Cannot be used when there is humidity of high moisture content present
Requires fewer bags
Cannot handle high temperatures (unless you use special filter media
Do you have a new dust collector project in the works and need help determining the volume? Our introduction to dust collector volume can help with that.
The Right Volume
The most important consideration to factor into a new dust collector is making sure the airflow or volume of the dust collector is efficient at capturing dust and is right for your application.
For instance, if the volume of your system is too low then your system will not filter dust as efficiently. As a result, your production, air quality and life of your collector can be shortened. Similarly, if it is too high then your energy consumption costs can be higher and you could disrupt the process of your application.
Measurement of Volume
You measure volume in cubic feet per minute or otherwise known as CFM. CFM is a measurement of airflow related to air conditioning, heating and ventilation environments. In dust collector applications CFM measures the amount of air per minute that can be moved from a space.
Work environments vary dramatically from one another based on several variables. Even very similar environments can require vastly different volumes. To determine the right capabilities for a new dust collector, here are some variables to consider carefully.
How are you collecting your dust?
What is the size of your duct being used to collect the dust?
What is the cubic feet of your work environment?
Calculating volume for new installations.
Do you need more detailed information? Download our full guide to dust collector volume below. In addition, it comes with a chart that can be helpful for your new dust collector project.
Which is better, Lower or Higher Air-to-Cloth Ratio?
Generally the lower your air-to-cloth ratio, the more effective your system is at removing dust from your work environment.
If you operate on a higher air-to-cloth ratio, one of the common issues you will encounter is a decrease in suction. This happens because there is too much dust to capture with an insufficient amount of filter media. The filter cake on your bag eventually builds up too quickly. As a result, your air velocity and suction decreases. From there it’s a domino effect and your plant air quality decreases, filters clog quicker, and valve life expectancy is impacted. So, you’ll be performing change-outs more frequently which will cost both time and money.
How to Calculate Air-to-Cloth Ratio
To calculate air-to-cloth ratio, take the amount of airflow (CFM) and divide that by the amount of filter area within your dust collector.
For example, if you’re calculating for a cartridge collector, a typical range would be a 4:1 air to cloth ratio. Keep in mind that environments with a large ventilation area and more pick up points require a system with a higher CFM to provide adequate suction. Would you like to know which air to cloth ratio may be right for your project? If so, download our air to cloth guide which provides the recommended ratio for a wide variety of applications.
