Learn About Common Filter Bag Finishes Such as Calendering (Glazing), Singeing, Napping, and Coating.
There are a few different finishes and treatments that can help lengthen the life of your filter bag, improve its stability, and make cleaning an easier process. Filter performance is directly related to how well filters can tolerate the work environment it’s in. So applying a specific finish or treatment is one way to achieve better performance.
Fabrics for filters are usually made of woven felts, non-woven felts, natural fibers, synthetics, or polyphenylene sulfide. Natural fabrics, such as wool and cotton, are usually preshrunk to eliminate bag shrinkage during operations. Certain fabrics can be treated with silicone to give them better cake release proprieties. When it comes to both synthetic and natural fabrics, processes such as calendering (glazing), napping, singeing, or coating are typically applied.
Calendering (Glazing)
Calendering, also known as Glazing, is the high-pressure pressing of the fabric by rollers to flatten or smooth the material. Calendering pushes the surface fibers down onto the body of the filter medium. Calendering can be applied to various media such as polyester, polypropylene, and aramid. This is done to increase and uniform surface life, improve stability and reduce shrinkage.
Napping
This process is the scraping of the filter surface across metal points or burrs on a revolving cylinder. Napping raises the surface fibers, creating a “fuzz”, that provides a large number of sites for particle collection by interception and diffusion. Fabrics used for collecting sticky or oily dusts are sometimes napped so they can provide better collection and an easier cleaning process.
Singeing
Singeing is done by passing the filter material over an open flame. This removes any straggly surface fibers and results in a more uniform filter bag surface. You can typically see this process done on the following fabrics; polyester, polypropylene, acrylic, aramid, ryton, and P84 felts.
Coating
Also known as resin treating, this involves immersing the filter media in natural or synthetic resin. This process helps lubricate the woven fibers, provides high-temperature durability, and various fabrics.
We’re excited to launch two new how-to videos to help you properly install and measure your dust collector filter bags on our new US Air Filtration YouTube channel! Stay tuned for additional troubleshooting and how-to videos to come.
What is the difference between a baghouse and a cartridge collector? Which one is right for my application? These are some very good questions to ask as you begin searching for the right dust collector for your project. This article will help you better understand the difference between the two and what would be a good fit for your operation.
First, we can start with the similarities between baghouses and cartridge collectors. Both of these are larger scale filtration systems that are very efficient. They use filters that must be cleaned periodically to ensure a longer bag life and more effective filtration and performance.
Airflow Differences
One of the first points of difference is their airflow filtration range. Baghouses are typically necessary in an application with more than 1,000 CFM. Cartridge filters can be used for lower scale projects that start at 500 CFM.
If your project emits more than a 55 gallon drum of dust per day a baghouse would be the recommended filtration system. Cartridge filters are ideal for applications that use less than a 55 gallon drum of dust per day.
Maintenance
Cartridge filters are easier to maintain than baghouses. A cartridge collector is smaller and often the filters are pleated, giving you more square footage of filtration in a more compact area. Cartridge filters can be replaced from the outside of the collector which eliminates contact with the dust and sometimes harmful materials that the cartridges are filtering. You can save on labor costs and time because cartridges are larger, so you don’t have to replace as many.
Baghouses are typically much larger and house more filters than cartridges. Automated cleaning systems in baghouses make it much easier to keep filter bags clean and reduce bag wear.
When it is time for replacement, there are more bags to replace and the servicer has to go inside the baghouse to change out the bags which can increase contact with harmful particulate or fumes.
To learn more about the key differences between baghouses and cartridges including ballpark costs, lead times, installation and view a comparison chart highlighting key differences in airflows, design features and more, download ourfree detailed guide to baghouses and cartridge collectors.
What is a MERV Rating and Which MERV Rating is Right for my Dust Collector?
Picking a filter material for your dust collector is like trying to pick a new car. There are many options, some value-priced, others more expensive. Factors to be considered include performance, the environment where the car will be driven and what the car will be used for. Is it toting a family of five or one? Will it be used in a cold weather or warm weather climate? For example, while a BMW convertible is a beautiful car that no doubt has wonderful performance and luxury features, it’s probably not the best most practical option for a family of five with three children living in Alaska. Likewise, a single young woman living in an apartment New York City probably doesn’t need a large pick-up truck.
It’s important to match the performance and characteristics of the vehicle with the needs of the buyer. The same is true for filters. A woodworking facility processing sawdust that generates large dust particles probably doesn’t need a filter that is designed for fine dust capture. Likewise, a plant that is processing carcinogenic materials will need to be very efficient at capturing microscopic dust particles. One measure that can be helpful in determining which filters are more efficient at capturing fine dust particles is called a MERV Rating.
The term MERV is an acronym that stands for “Minimum Efficiency Reporting Value”. MERV Ratings are numerical values assigned to filters that assess the particle size efficiency or PSE of a given filter material. PSE is the average particle size that is captured by the filter after several filtration tests are performed. Testing involves filtering various size particles from microscopic dust particles to larger particles such as sawdust or pollen through the system to measure filter efficiency.
The higher the MERV rating, the better the filter is at capturing very small particles of dust. For example, a filter with a MERV rating of 20 would be able to efficiently capture nearly 100% of all microscopic particles such as viruses, smoke, and carbon dust whereas a filter with a MERV of 4 efficiently captures 20% of pollen, dust mites, and other larger dust particles.
How does MERV Rating affect my dust collector’s performance?
A higher MERV rating does not necessarily mean that the filter is going to capture more dust or improve performance for your application. The key factor in deciding which MERV rating will maximize your collector’s performance and efficiency at the best value is to look at the size of the dust particles in your work environment. Applications that filter large particles of dust such as wood dust or metal dust are not going to see a big improvement in efficiency and performance by using higher MERV rated filters. MERV ratings should be considered carefully if the dust being captured is very small. In applications where smoke is being filtered off a plasma cutter, for example, you may see a big difference in performance and efficiency by selecting a filter with a higher MERV rating.
We offer filters for every MERV rating filter and can help you choose the right filter for your application that will get you the best performance at the best price and efficiency. To learn more, download our FREE Guide and MERV Rating Application Chart by completing the form or call us today at 888-221-0312.
Choosing the correct dust collector filter media for your dust collector bags is an important and sometimes difficult process. Filter bags come in many different materials from woven to felted and more. The first step is to consider what type of application and dust collector the filter bags will be used for and the work environment. This will help you understand which bags will give you the best efficiency and performance for your unique application. Narrow down your options by looking at the following key factors:
• Temperature – do your bags need to withstand extreme temperatures?
• Product – what are you filtering?
• Chemistry – can your bags withstand the chemical make up of the dust particles?
• Resistance- is the filter media able to resist the wear and tear of the dust?
• Particles – what is the size of the dust particles that are being filtered?
• Current filter media – What is currently being used in your collector today?
Environment is a critical factor in choosing the right filter. Filter bag performance is directly related to how well it can tolerate the environment in which it is being used, how efficiently it can remove the dust particles from its fabric, and how easily the filter material can be cleaned by the collector.
Here is a list of common filter medias used in dust collector applications:
• Woven felts
• Non-woven felts
• Natural fibers
• Synthetics (Thermoset or Thermoplastics such as Polypropylene “PPRO” – A simple test to determine if a material is a thermoplastic is to take a small swatch and put a flame to it. A thermoplastic material will begin to melt when exposed to direct heat.
• Polyphenylene sulfide “PPS” – Polyester “PE”)
Once you’ve decided on the right filter material for your dust collector, you will want to accurately measure your filter and assess the bag construction on top and bottom to make sure you receive the correct bag for your dust collector. To learn more about how to measure your filters and understand top and bottom configurations as well as receive a comprehensive guide to each of the major filter medias available, download our FREE Guideto filter bag medias by completing the form. Or call us today at 888-221-0312!
Pulse jet cleaning is the most common type of dust collector available today and makes up nearly 50% of all new dust collector installations. In a pulse jet dust collector, filter bags are cleaned when a high pressure jet of air, or compressed pulse, is sent through the system to shock the bags and remove and fracture the dust cake. One advantage of pulse jet dust collectors is the bags can be cleaned while the dust collector is still running so plant production and processing can continue without interruption.
It’s important that bags are cleaned regularly to improve airflow through the system, prevent plugging from dust build up, and improve pick up velocities. But it may be time consuming and labor intensive to know how frequently and how often the bags need to be cleaned. On demand cleaning is an automated cleaning system for your dust collector that can improve your dust collectors efficiency and performance while reducing energy consumption and labor costs.
How On Demand Cleaning Works
In a pulse jet dust collector, as dust starts to cake on the bag the differential pressure between the dirty air environment and the clean air environment increases. With on demand cleaning, the control panel is set by the operator to clean the bags only when the differential pressure reaches a high range, then the system will pulse down to a lower range. Cleaning pauses until the differential pressure reaches the high range once more and the system will automatically pulse down again. This continues as an ongoing cycle that is performed the entire time your dust collector is running.
Check out this video to learn more about what on-demand cleaning can do to improve your dust collector and your operation.
Applications for worksite dust collection and removal are quite diverse, ranging from small woodshops to large automotive metal casting foundries. Since each facility has different products and needs, it is important to know which type of dust collector will offer the best performance and efficiency for your unique facility.
There are many factors that go into selecting the type and size and customized options of a dust collector. This article is meant to only be an introduction and to give an overview of some of the more typical factors that should be considered and to give some basic examples.
The three main types of pulse jet dust collectors include baghouses, cartridge collectors and bin vents. Here is a brief summary of each and some examples of common worksite applications.
Baghouses
Baghouses are best suited for large volume dry particulate dust capture. They are typically the largest, and most expensive option for dust collection, performing best where a high volume of dust collection and removal is necessary. Baghouses perform best in applications collecting more than one 55 gallon drum full of dust per day and where airflows exceed 1,000 CFM. Baghouses are usually custom-designed and have the largest footprint of all dust collectors. They are also the best option when higher temperatures over 375 degrees are required.
Common Baghouse Applications:
Automotive Castings
Mining
Foundries
Tile, Drywall, Fiberboard manufacturing
Baghouses can be used for all applications except the following:
Smoke / fumes
Non dust collector applications (not a dry particulate)
When very high efficencies are required
Cartridge Dust Collectors:
Cartridge dust collectors are typically less expensive than baghouses and have a much smaller footprint. They work best when there are limited space or height restrictions in the work environment. The use of pleated bags in cartridge dust collectors increases filter media square footage without the need for additional space, allowing greater airflow in a much smaller area.
Cartridge dust collectors are available pre-fab and in many cases do not need to be custom-built, reducing both costs and lead time. For most applications, they are just as efficient at removing dust as baghouses with a few exceptions such as sawdust removal and others.
Cartridge collectors perform best in environments where greater than 500 CFM dust removal is required and there is low dust loading (less than one 55 gallon drum). A cartridge collector is also easier to maintain than a baghouse – filters are replaced from outside the collector, reducing health and safety risks from having to enter the collector to replace filters.
Common Cartridge Dust Collector Applications:
Steel Fabrication
Bulk Powder Processing
Rubber Plant
Here are a few exceptions where a cartridge collector would not be a good fit:
Higher moisture applications
Higher temperatures
Many wood dust applications
Foundry sand because of moisture
Large particles such as paper scraps, pulp, pebbles, and other particles that can cause filter damage.
Bin Vents
Bin vents are designed to filter the air in work environments where product such as grain, sand, or cement, etc. is being pumped from one location to another. They are designed to efficiently vent silos and tanks while keeping the product inside the silo. Most often they are used for tanks when trucks transfer cement from the collector to the silo. Like cartridge collectors bin vents have a small footprint and are designed to handle lower volume of dust than a baghouse, bin vents typically handle between 400 and 10,000 CFM/ dust loading. Here are a few applications where a bin vent is recommended:
Tank loading. Allows the air to go out of the tank and the product to stay in.
Product transfer from one tank to another.
Conveyor Vent. When a conveyor of product is transferred from one belt to another it is necessary to ventilate the environment so dust doesn’t get in the air.
To learn more about which type of dust collector would fit your needs, call one of our engineers today at (888) 221-0312.
PTFE membrane, commonly known as “Teflon” has been widely used on cookware for the past 60 years because of its superior non-stick qualities. It’s also very useful when applied to outerwear, because it is waterproof and breathable at the same time. When viewed up close under a microscope, PTFE material is covered in tiny microscopic holes that looks similar to swiss cheese. These tiny holes allow vapors and gases such as air, water vapor to cross through the material easily while stopping denser materials including liquids, and dust particles from crossing through, making it the perfect filter material to use in dust collector applications.
How PTFE Membrane Works:
On a normal filter bag, dust begins to collect on the surface of the bag and creates a build-up of dust called a filter cake. In the cake, the particles come together and create a fairly good efficiency, typically about 99.97% or better. The filter acts only as the support for the cake and does not provide much filtration at all. When the bags are pulsed to clear the filter cake, some of the cake releases, but over time, the dust particulate embeds itself into the fabric causing failure or plugging of the system.
Conversely, when PTFE membrane is added to a bag it acts as the filter cake. The efficiency of the membrane is higher, exceeding 99.99% and can reach as high as 99.999%. The membrane allows for very little dust to stick to the bag so when the bags are pulsed, they clean very well. The dust stays on the surface and never gets embedded into the fibers of the bag.
This increases bag life but also allows the system as a whole to perform more efficiently. PTFE membrane bags don’t require pulsing as frequently as normal filter bags because the bags stay cleaner and the membrane itself reduces filter cake. Less pulsing means less wear and tear on the bags and on the system. Not only will the bags perform better longer, but the pulse valve solenoids and diaphragms won’t need to be replaced as often.
How On-Demand Cleaning Works:
On-demand cleaning allows for the bags to clean only when the differential pressure gets to a high range as set by the operator and then pulse down to a lower range. The cleaning then pauses until the high range is again reached, thereby only cleaning when demanded. The cost of the cleaning timer and module required is insignificant compared to the savings in cost from bag wear, change-outs and plant down-time.
Benefits of Using PTFE Membrane and On-Demand Cleaning:
Longer bag life (up to and exceeding 2 times normal life)
Bag fibers do not become entrained with dust
Bags require less pulsing, reducing wear on the bags.
Labor savings on bag change outs (not required as often)
Bags can withstand some moisture and still perform well
System will rarely plug because bags do not become blinded
Less compressed air consumption resulting in less energy consumption
Pulse valve diaphragms and solenoids will last longer (due to less usage)
Less maintenance and related plant down-time due to dust collector issues
More consistent and increased air flow due to a lower pressure drop
Better pick-up velocities and better plant hygiene due to better air flow
With the use of PTFE membrane bags and on-demand cleaning, your system should perform at its peak and provide all the benefits mentioned above. We recommend that these bags and timers be utilized in nearly every application to save costs all around and allow peak system performance.
