How to Install a Dust Collector Differential Pressure Sensor

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Best practice for installing a baghouse magnehelic differential pressure gauge

This simple baghouse accessory can mean the difference between a properly functioning baghouse and an operational disaster! Use this guide to ensure proper installation and maintenance of your differential pressure device.

By Dominick DalSanto
Baghouse Technology Expert and Sales Director
Baghouse.com

One of the most common issues we identify during our dust collection system audits/inspections  is poorly installed and maintained differential pressure system components (e.g. magnehelic/photohelic gauges, DP air lines, DP taps, etc.). As we have covered in previous articles in this series, having accurate differential pressure readings is essential to proper dust collector operation.

Baghouse differential pressure air lines

Avoid the example here. Avoid splitters and crooked lines.

I was recently asked by one of our readers if we could write an article on how to install the differential pressure reading system components for a baghouse. The process, like many baghouse-related items, is not complicated. However, there are some industry best practices that make maintenance easier and reduce likelihood of problems in the future.

This guide can be used regardless of what kind of differential pressure reading system you are going to use. The process is the same for magnehelic and photohelic gauges, as well as timer boards and control boards with on-board pressure sensors.

Installing a Baghouse Differential Pressure System

  1. Determine what kind of differential pressure controls you will use
    • Magnehelic gauges are simple and provide reliable data. However, they alone cannot be used to control the cleaning system on a baghouse.
    • Timer boards are useful for processes that are consistent in dust loading and operating schedules, but must be manually set by operators.
    • Clean on demand systems are the best choice for controlling a dust collector. Often, these systems are all in one controllers, or they are a mix of a control board with an external photohelic or magnehelic gauge for pressure readings
    • Air lines running between the controls and the baghouse can be plastic, carbon fiber, or even metal (copper or aluminum). Plastic or carbon fiber lines are easier to run, but metallic lines are much more durable and will require far less maintenance in the long run.
    • Consider installing secondary magnehelic gauges for redundancy and easy reading by maintenance personnel.
  2. Decide on the location of your control(s)
    • Locate your controls where they can be easily accessed by maintenance personnel. With smaller units often the most convenient location for controls and gauges will be on the ground level. Good locations include on supports or nearby walls. On larger units, controls are best located near the doors or along access platforms. Common locations include next to the door, above the pulse valves and compressed air header, or on a nearby wall or column.
  3. Decide on the location of your air taps and plan your air line runs
    • Air taps are best placed near the corners of the clean and dirty plenums. This minimizes the amount of dust that can enter back into the air lines and possibly foul the DP sensors. Try to keep them about at least 6″ from the walls and in the corners where practical. Keep both taps near each other for easy access when performing maintenance.
    • Decide on the best path for your air lines. Avoid runs over 100′ as this may affect the accuracy of the readings.

Common Issues with Dust Collector Differential Pressure Gauges

Problem: I hooked up the DP lines, but my DP sensor is giving me a negative reading.

Solution: You likely have the lines mixed up. Try switching the lines on the inputs.

Problem: I have the lines set up correctly, but I am getting very low readings (usually under 1″).

Solution: Before installing the both lines, you need to zero out the gauge. Attach one side and then with the other one off zero out the DP sensor. Now when you attach the second line it should give an accurate reading

Problem: My controller is setup, but the solenoids are not firing.

Solution: Check your wiring to make sure you have everything correct. Often, the common line from the solenoid to the control is mixed up with one of the control wires. Double check everything and follow the wiring diagrams from your manufacture exactly. 

Special Thanks

A special thanks goes out to one of our readers, Tim Skiba, for suggesting this subject for an article.  If you have any topics that you would like to see discussed on Baghouse.com, please share them with us in your comments below. Thank you so much for reading.

 

| Dominick DalSanto is an author & dust collection technologies expert, specializing in dust collection systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as sales director at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

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Free Site Visits In Las Vegas – Free Dust Collector Inspections

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Baghouse.com now offers free site visits to new customers in the Las Vegas area to all new customers. 

By Dominick DalSanto
Baghouse Technology Expert and Sales Director
Baghouse.com

Baghouse.com News | As of May 1st, Baghouse.com now offers free on-site visits to all new customers in the Las Vegas, Nevada area. These visits will provide potential customers with a more personalized relationship with the company. Upon request, a baghouse engineer will arrange to visit a facility on-site to introduce the company’s products and services. Where possible, the baghouse expert will tour the facility and examine its dust collection systems. When finished, the Baghouse.com representative will review their findings with plant personnel and issue a brief written summery within one week. This will include an overview of the facility’s dust collection systems and general recommendations for areas where improvement can be made.

Benefits of a Baghouse.com Dust Collector Report

Free dust collector inspection and report from Baghouse.com

Free dust collector inspection and report from Baghouse.com

Many of our current customers have benefited from our recommendations. By putting into practice our recommendations they increased efficiency, capacity without large capital investments, reduced down-time, operating costs, and lowered emissions and improved safety (due to air quality) within their facilities.

Here are just some of the items we often identify during a free site visit:

  • Troubleshoot existing issues and work with staff on how to resolve them
  • Filter selection: recommend alternative fabrics, finishes (e.g. PTFE membrane), filter types (e.g. pleated filters
  • Baghouse condition and unit selection:
    • Recommend repairs (structural, pulse valves, gaskets, etc.)
    • Identify shaker and reverse air units with potential for retrofitting into newer pulse jet style
    • Condense several inefficient small units into one larger system,  etc.
  • Examine current operating methods and make recommendations on how to improve efficiency, reduce operating costs and system downtime (e.g. startup and shut down procedures, fan operating parameters, cleaning system settings, etc.)
  • Examine current maintenance procedures and make recommendations for improvement. Includes daily, weekly, monthly, yearly procedures, inspection checklist, handling of replacement bags, diagnosing need for bag replacement, proper bag replacement techniques, etc.
  • Replacing out of date equipment and methods with latest technology, such as pleated filters, clean-on-demand cleaning, PTFE membrane filters, etc.
  • Recommendations for new OSHA standards for combustible dust, such as explosion protection and fire suppression systems.

Request Your Free Dust Collector Report Today!

To request a free visit in the Las Vegas area, simply contact Baghouse.com by phone at 800 351 6200 or send us an email and ask for information about our free Las Vegas dust collector inspections and reports.

For more information please see the following pages:

 

| Dominick DalSanto is an author & dust collection technologies expert, specializing in dust collection systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as sales director at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

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Baghouse Differential Pressure – How To Troubleshoot False Readings

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Baghouse differential pressure air lines

For baghouses to run efficiently, trustworthy differential pressure readings are required. How can you tell if your DP readings are accurate? What can you do if you suspect you are receiving false readings? This second article in our series on baghouse differential pressure will answer that question. 

By Dominick DalSanto
Baghouse Technology Expert and Sales Director
Baghouse.com

Why Worry About False Differential Pressure Readings?

As we mentioned in our previous article in this series, having accurate differential pressure readings is essential to operating your baghouse correctly, and efficiently. Operators base almost all of their operational decisions on baghouse DP. If they are given incorrect readings it could result in damage to the system, increase emissions, or even fire and combustible dust hazards.

For example, assume that a unit is giving readings that are lower than they actually are, 3″ w.g. when it really is running at 8″. Because the operator sees such a low reading, he could now make several incorrect operating choices that could have very severe consequences. He may take this low DP reading to mean that his filters are in good condition and do not need to be replaced. With blinded bags, he could begin seeing decreased system performance. Or perhaps his bags could begin producing higher emissions levels thus causing the plant to exceed its air permits, potentially leading to heavy fines and sanctions.

While we cannot detail every possible problem that could arise from this, the point is clear. So what can and maintenance personnel do if they they are receiving incorrect DP readings?

How To Troubleshoot Differential Pressure

Maintenance personnel should examine the DP instruments and determine if there is any obvious problem. Lose connections, backwards connections, and obviously broken gauges are common enough that they should be expected.  Other times, maintenance personnel will need to troubleshoot the instruments to diagnose and remedy less conspicuous issues.

Maintenance personnel will need to determine whether the individual pressure gauges are faulty, or simply have blocked lines coming into them. We recommend the following troubleshooting procedure:

  1. Disconnect all gauges, controller boards, etc., from air lines coming from the collector.
  2. Using compressed air, clean all air lines thoroughly, making sure to blow back into collector.
  3. Using a handheld DP gauge (a normal manometer with flex tube connectors will suffice), hook up the air lines from the collector to obtain the operating DP.
  4. Reconnect the newly-cleaned air lines to the controller board and/or pressure gauge.
    1. If the controller board/pressure gauge reads the same as the handheld gauge did after cleaning the lines, then the controller board pressure sensor and/or pressure gauge is working properly
    2. If the controller board/pressure gauge reads the differently than the handheld gauge did after cleaning the lines, then the controller board pressure sensor and/or pressure gauge is not working
      1. (For the baghouse-mounted DP gauge) Replace with new gauge.
      2. (For controller board) Contact manufacturer about possibility of replacing only the board’s pressure sensor.
        1. If not possible, replace entire board with new controller board.
  5. Remove all unnecessary line splitters, additional lines, and long runs, ensuring all gauges are located as close as possible to the air taps (within 10’ – 15’)
Baghouse differential pressure air lines

Avoid the example here. Avoid splitters and crooked lines.

NOTE: When connecting the new gauge to the clean and dirty side lines, make sure to connect them to the correct ports on the gauge. They should be marked “HIGH” and “LOW”. Just remember, that if hooked up backwards, the needle will pull backwards, instead of giving a positive reading.

How To Prevent False DP Readings

It is important to remember that just because you fixed this problem once, it likely will come back again and again over the life of the baghouse. Inspecting and cleaning/repairing the DP gauges and air lines should be a regularly scheduled maintenance task for all baghouses.Industry best practices should be followed when installing the gauges and air taps to reduce the likelihood of fouling.

Notice in the picture to the right how the maze of lines coming in and out this DP gauge. Best practice is to have just one line from each side of the baghouse coming into the gauge. The lines should run in the most direct and shortest path possible. For this reason, avoid locating the gauges exceedingly far from the unit, such as in other rooms or other floors. Further, to avoid buildup in lines themselves, place the taps near the top corners in each side of the unit.

Baghouse Differential Pressure - Good air lines

A better example of how lines should be run.

Also, using copper line as opposed to plastic or rubber tubing is preferable and we facilitate easy cleaning and is far more durable.

Once You Have Accurate Readings

With your now trustworthy readings in hand you can now begin consider what these readings in conjunction with other available information is telling your about your baghouse.Our next article in this series will examine how to understand your baghouse DP readings and use it to make wise operating decisions.

 

 

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in dust collection systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Sales Director at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

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Introduction to Combustible Dust Explosions Common to Baghouses

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Guest Post By Bevin Sequeira
BS&B Safety Systems (Asia Pacific) Pte Ltd. 

Introduction to Dust Explosions

A Dust Explosion is the fast combustion of dust particles suspended in the air in an enclosed location. Coal dust explosions are a frequent hazard in underground coal mines, but dust explosions can occur where any powdered combustible material is present in an enclosed atmosphere or, in general, in high enough concentrations of dispersed combustible particles in atmosphere.

Dust Explosion at West Pharmaceutical Services

Dust explosion at West Pharmaceutical Services, North Carolina took the lives of 6 people in 2003

Dust explosions can lead to loss of life, injury, damage property and environmental damage as well as consequential damage such as business interruption losses.

Dust explosions involve most commonly “dust”, i.e. fine material. This can be the product being handled or it can be produced as the result of the processing. However, in many cases fine dust is present in material that is otherwise too coarse to pose a dust explosion hazard, either as part of the product or generated by attrition during handling or transport. Therefore, while replacing a fine material by a granular one (such as pellets or flakes) will reduce the dust explosion hazards, this may not be sufficient to eliminate the hazards. Similarly, a user of a granular material may process it to a particle size that introduces dust explosion hazards.

Many dust explosions that occur in process plants are relatively small, leading to limited damage. However, under the right circumstances, even small explosions can escalate into major incidents. This is most commonly the case when secondary dust explosions happen. The typical scenario is that a small “primary” explosion raises a dust cloud, often from dust deposited over time on plant surfaces, and ignites the resulting dust cloud. This “secondary” explosion takes place where often people are present, placing them in immediate danger. Secondary dust explosions can form a chain reaction that can run through a facility as long as fuel is present, leading to widespread devastation.

 

Conditions for Dust Explosion

Dust Explosion Pentagon

There are five necessary conditions for a dust explosion or deflagration:

1. Presence of Combustible Dust
2. Dust suspended in the air at a high concentration
3. There is an Oxidant (typically atmospheric oxygen)
4. There is an Ignition source ( Either Flames & hot surfaces, Spontaneous Ignition, Friction sparks, Static Electricity, Electrical Equipment’s, etc.)
5. Confinement (enclosed location)

Many materials which are commonly known to oxidize can generate a dust explosion, such as coal, sawdust. The dust can arise from activities such as transporting grain and indeed grain silos do regularly have explosions. Mining of coal leads to coal dust and flour mills likewise have large amounts of flour dust as a result of milling. A gigantic explosion of flour dust destroyed a mill in Minnesota on May 2nd, 1878, killing 18 workers at the Washburn A Mill.

To support combustion, the dust must also consist of very small particles with a high surface area to volume ratio, thereby making the collective or combined surface area of all the particles very large in comparison to a dust of larger particles. Dust is defined as powders with particles less than about 500 microns in diameter, but finer dust will present a much greater hazard than coarse particles by virtue of the larger total surface area of all the particles.

Sources of Ignition

There are many sources of ignition and a naked flame need not be the only one: over one half of the dust explosions were from non-flame sources. Common sources of ignition include electrostatic discharge friction arcing from machinery or other equipment or hot surfaces such as overheated bearings. However it is often difficult to determine the exact source of ignition post-explosion. When a source cannot be found, it will often be cited as static electricity. Static charges can occur by friction at the surfaces of particles as they move against one another, and build up to levels leading to a sudden discharge.

Combustible Dust Concentrations:

As with gases, dust is combustible with certain concentration parameters. These parameters vary widely across the spectrum. Highly combustible dust can form a flammable mixture with less than 15 g/m3.

Mechanism of dust explosions:

Imperial Sugar Explosion- Wentoworth Georgia

Imperial Sugar Explosion: Wentworth, GA
17 February 2008: 14 Fatalities

Dusts have a very large surface area compared to their mass. Since burning can only occur at the surface of a solid or liquid, where it can react with oxygen, this causes dusts to be much more flammable than bulk materials. For example, a 1 kg sphere of a material with a density of 1g/cm3 would be about 27 cm across and have a surface area of 0.3 m2. However, if it was broken up into spherical dust particles 50µm in diameter (about the size of flour particles) it would have a surface area of 60 m² This greatly increased surface area allows the material to burn much faster, and the extremely small mass of each particle allows it to catch on fire with much less energy than the bulk material, as there is no heat loss to conduction within the material. When this mixture of fuel and air is ignited, especially in a confined space such as a warehouse or silo, a significant increase in pressure is created, often more than sufficient to demolish the structure.
Even materials that are traditionally thought of as non-flammable, such as aluminium, or slow burning, such as wood, can produce a powerful explosion when finely divided, and can be ignited by even a small spark.

 

Combustible Dust Explosions Since Imperial Sugar Incident

Terminology:

Dust explosions may be classified as being either primary or secondary in nature.

Primary dust explosions: occur inside process plant or similar enclosures and are generally controlled by pressure relief through purpose-built ducting to atmosphere.

Secondary dust explosions: are the result of dust accumulation inside the factory being disturbed and ignited by the primary explosion, resulting in a much more dangerous uncontrolled explosion inside the workplace.
Historically, fatalities from dust explosions have largely been the result of secondary dust explosions.

Best engineering control measures which can be found in the National Fire Protection Association (NFPA) Combustible Dust Standards include:

• Oxidant Concentration Reduction
• Deflagration venting
• Deflagration pressure containment
• Deflagration suppression
• Deflagration venting through a dust retention and flame-arresting devices
• Spark Detection & Extinguishing Systems

 

 

 

Explosive Materials:Dust Explosions - Bucket Elevator Explosion The following materials are prone to dust explosions.
• Coal
• Fertilizer
• Cosmetics
• Pesticides
• Plastic & plastic resins
• Wood
• Charcoal
• Detergents
• Foodstuffs (sugar, flour, milk powder, etc.)
• Ore dusts
• Metal dusts
• Graphite
• Dry industrial chemicals
• Pigments
• Cellulose

Industrial Equipment:
Typical industrial equipment’s that require explosion protection.
• Dust Collectors
• Dryers
• Cyclones
• Crushers
• Grinders
• Silos
• Pulverisers
• Conveyors
• Conveyor ducts
• Screw conveyors
• Bucket Elevators
• Furnaces
• Hoppers
• Bins

Conclusions

Many reported dust explosions have originated in common powder and bulk solids processing equipment such as dust collectors, dryers, grinders/pulverisers, and blenders. Electrostatic discharges are frequently cited as the ignition source for dust collector explosions, whereas particulate overheating is the most common ignition source in dryer explosions, and friction/impact heating associated with tramp metal or misaligned parts is probably the most frequent ignition source in grinder/pulveriser explosions.

Dust explosions are often exacerbated by propagation through ducting between process equipment, frequently via dust collector pickup and return ducting. Moe widespread use of effective deflagration isolation devices in such ducting would clearly be beneficial in mitigating the damage and injuries from these propagating dust explosions. (See article Dust Collector Fire and Explosion Highlights Need for Combustible Dust Considerations In System Designs)

Secondary dust explosions in processing buildings probably cause the largest numbers of dust explosion fatalities and injuries. One crucial aspect of secondary dust explosion prevention and mitigation is greater awareness of good housekeeping and maintenance practices to prevent particulate leakage from equipment and subsequent accumulations of dust deposits in large areas of the buildings.

 

About the Author

Bevin Sequeira holds a B.E. (Mechanical) degree & a MBA (Marketing) specializing in business development & enhancement of virgin markets all over the globe. With over two decades of international working experience in the industry, Bevin’s knowledge of the industry spans various sectors like Iron & Steel, Foundry, Chemicals & Fertilizer, Power, Food, Pharma, etc.  He is currently serving as Regional Sales Manager at BS&B Safety Systems (Asia Pacific) Pte Ltd. specialising in Combustible Dust Explosion Protection Systems & Risk Management. In his spare time, Bevin likes to read, travel, socialise & collaborate with business houses for M&A, Management Consultancy, etc.

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Baghouse Differential Pressure – Why Important?

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Diagram of how to install a magnehelic differential pressure gauge on a baghouse dust collector.

Accurate differential pressure readings are essential for efficient baghouse operation. This article outlines the importace of baghouse differential pressure and what baghouse problems it can be used to diagnose. 

By Dominick DalSanto
Baghouse Technology Expert and Sales Director
Baghouse.com

Baghouse Differential Pressure – Why Important?

Within a baghouse a number of factors must be controlled to ensure the efficient operation of the system at all times. Of these, the most important variable to control is the system differential pressure. This measurement is the key indicator of how the baghouse is operating and the most important factor to consider when diagnosing and troubleshooting issues with the baghouse system.

Over time more and more dirt will penetrate deep into the fibers of a bag being harder to remove. When this happens the bags become blinded or are unable to be adequately cleaned. This causes massive differential pressure increases.

Over time more and more dirt will penetrate deep into the fibers of a bag being harder to remove. When this happens the bags become blinded or are unable to be adequately cleaned. This causes massive differential pressure increases.

Differential pressure (also known as pressure drop or Delta-P) is the difference in pressure between the dirty-air side of the baghouse and the clean-air side. As in the incoming air is pulled through the filter media (i.e. filter bags) vacuum is lost, resulting in the air entering the baghouse having a weaker vacuum than the air exiting the baghouse. For example, let’s say that the system fan is pulling 10″ w.g* of vacuum pressure. When the dirty air comes into the baghouse the pressure is at 3.5″ w.g.* of vacuum, but after entering into the baghouse and passing through the filters the pressure rises to 10″ w.g.. This means the pressure drop across the baghouse is 6.5″ w.g. (Note: This example assumes a clean-air side fan or negative pressure system)

Differential pressure readings are used to determine a number of things about the operation of a baghouse system, such as filter bag condition,  and structural problems with the unit, (airlock and conveying system condition and door seals condition among other things). Furthermore, a high system differential pressure usually indicates that the system is not running efficiently and therefore is incurring higher operating costs than it should under optimal circumstances. The following problems can be diagnosed from observing the system differential pressure:

Filter Bag Condition

  1. Bags are blinded off
    • Dirty bags will become more resistant to airflow thus causing the force to push the air through them to rise.
  2. Bags have holes in them
    • This will create a path of less resistance for the air to flow through leading to lower pressure drop
  3. Bags are not installed properly
    • See above

Structural and Sealing Issues

  1. Leaks within the structure
    • Common leak areas include airlocks, welds, joints (especially panelized construction units), and door seals
  2. Airlock leaks
    • Common around flaps,rotars, gaskets and connection points.
  3. Conveying system leaks
    • Common at connection point to hopper/airlock, holes in ductwork structure, etc.
  4. Doors and hatch sealing
    • Gaskets on all doors and hatches, including viewports. Also includes making sure all doors have sufficient fasteners (i.e. bolts) to secure the door/hatch securely to form a tight seal.
Diagram of how to install a magnehelic differential pressure gauge on a baghouse dust collector.

Diagram of how to install a magnehelic differential pressure gauge on a baghouse dust collector.

Why High Differential Pressure Means Higher Operating Costs

Controlling your baghouse differential pressure is required to get the maximum performance and efficiency from your system. If your system is running at a high differential pressure it will inevitably cost more to operate, have lower performance and experience more downtime. High DP means the system fan needs to work harder to pull the same amount of airflow throughout the system. IF DP starts to rise above the recommended levels,  maintaining the same level of draft (i.e. suction) at all of the systems pickup points will prove difficult. This will lead to much higher energy costs to run the system fan at high speed and can if over taxed lead to premature fan/motor failure. If the system fan is not adjusted to compensate for the higher differential pressure, the system will lose draft at all of its pickup points. This will mean less performance from your system and inescapably cause problems for your facility process whatever it maybe, especially so for certain industries that are more dependent on the dust collection system as part of the process such as cement, powdered metals, chemical processing, etc. In the end, this will result in the process being shutdown or even a shutdown of parts or the entire facility until the system is running again.

Conclusion

Clearly, it is of vital importance for maintenance staff and operators to keep close watch on dust collection system differential pressure. If system DP is higher than recommended it can be a indicator of several potentially serious issues, ranging from blinded bags, to holes in the structure to poor seals, etc. Accordingly, obtaining accurate differential pressure readings is vital to have an accurate picture of what is going on within your baghouse system. But what can you do if your equipment is giving you suspicious or even false readings? How can you determine when your DP gauges and controls are sending false readings? These questions will be in the following article in the series: Baghouse Differential Pressure – How To Troubleshoot False Readings

Footnotes:

* “w.g. stands for inches of water gauge, that is vacuum pressure as measured in inches of water (sometimes mercury) as in a magnehelic gauge.

 

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Sales Director at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.
Baghouse.com Corp

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Industrial Air Permits – New Clean Air Regulations and Baghouses

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Previous Baghouse.com Articles on Air Permitting:

By Dominick DalSanto

October 3, 2012 – Baghouse.com | Recently, the EPA has been busy issuing new air pollution regulations (Cross-State Air Pollution Rule, Cement MACT, Mercury MACT, etc.) and tightened several exiting ones (NESHAPs, NAAQs, etc). With the new standards, and revisions to existing ones, many formerly compliant facilities may not find themselves no longer able to meet their existing air permits. In addition, some facilities will need to complete the application process again for new permits based on the new standards. This process can be exceedingly difficult, due to the complexity of the regulations. Many facilities end up getting lost along the way, potentially costing them millions of dollars in the process.

A while back Baghouse.com had the opportunity to speak with Trinity Consultants, an international firm that specializes in assisting industrial companies with air quality regulatory compliance challenges, about the coming changes in the regulatory scene and how companies can avoid getting lost in the process. The following are some excerpts from that interview that we feel will be helpful for our readers.

Interview with Trinity Consultants

What would you say is the most difficult section of current clean air regulation for industry to come into compliance with?

“At present, the new National Ambient Air Quality Standards (NAAQS) and associated U.S. EPA dispersion modeling requirements for demonstrating compliance with nitrogen dioxide (NO2), sulfur dioxide (SO2), and fine particulate matter (PM2.5) are the most difficult provisions of the clean air act regulations for new or modified facilities.  U.S. EPA has also promulgated additional challenging requirements that affect specific industries or specific source types including National Emission Standards for Hazardous Air Pollutants (NESHAP), Maximum Achievable Control Technologies (MACT), and New Source Performance Standards (NSPS) for industrial-commercial-institutional steam generators (boilers), electric utility steam generating units (utilities), portland cement manufacturing, and others.”

What problems do you encounter with regards to dust collection/particulate matter (PM2.5)emissions?

“Dust collection, capture, and control is an important consideration for compliance with the PM2.5 NAAQS as well as compliance with the new NESHAP, MACT, and NSPS noted above. ”

One of the “scariest” new regulations is the Mercury MACT; what role will baghouses play in meeting these new standards?

“Most technologies for collecting mercury emissions involve the use of a baghouse. The most common include injecting a material to absorb the mercury in the airstream, usually activated carbon or a proprietary sorbent compound, which then needs to be collected from the airstream just like any other particulate matter would be, by the baghouse. In some cases the only way to handle this increased particulate load is to upgrade the baghouse. This could mean replacing the bags with more efficient PTFE membrane bags, expanding the baghouse (either by added more compartments, using a larger baghouse, or by switching to pleated baghouse filter elements).”

What problems do you encounter frequently with the regulatory process that are the most frustrating?

“We have clients that have had to cancel proposed capital expansion projects due to the economic and/or operational infeasibility of complying with the new NAAQS provisions for PM2.5, SO2, & NO2.”

What can companies do when they feel overwhelmed by the often complex permitting process to make sense of the situation?

“Our clients frequently request staff from Trinity Consultants to train, advise, or develop strategic guidance for their environmental, management, operations, and/or legal staff on the complex environmental topics or have Trinity Consultants directly assist with their permitting and compliance needs.”

What do you feel is the most important thing for companies to keep in mind with regards to compliance issues?

“Stay up to date (fresh, timely) on the regulatory rule changes affecting their industry.  Participate in industry associations or work groups that focus on environmental requirements for your industry.  Companies can also find timely updates, regulatory notices, and training courses at www.trinityconsultants.com.  We also suggest that companies subscribe to Trinity Consultants’ periodic publications which include Environmental Quarterly and eNews at www.trinityconsultants.com/subscribe”

How do these previously mentioned regulations come into play with regards to dust collection? (National Emission Standards for Hazardous Air Pollutants (NESHAP), Maximum Achievable Control Technologies (MACT), and New Source Performance Standards (NSPS) for industrial-commercial-institutional steam generators (boilers), electric utility steam generating units (utilities), portland cement manufacturing, and others)

“For existing utility sources, the 0.03 lb/MMBtu limit should easily be met with a good ESP, and does not force you into a baghouse – our understanding is the crossover point may be about 0.005 lb/MMBtu filterable.  For new utility sources, the limit is very low and could only potentially be met with a baghouse.   

For cement plants, ESPs are likely a thing of the past and existing baghouses will likely need new filter media or polishing baghouses.  There are many retrofit projects currently being pursued.  With the new NSPS, lower than 0.002 gr/dscf bags are being evaluated.  Getting suppliers to guarantee PM emissions limits on new units that meet the standards will be very challenging.  In some places, two bags may be needed in series, one for lime injection providing some scrubbing effect and then a final bag house.  Meeting the PM limit is very challenging for the cement industry, requiring periodic maintenance program improvements, even a single bag leak can take you out of compliance.   

Industrial-commercial-institutional boiler considerations:   
For solid fuel-fired boilers, it appears that fabric filters will be required (whenever the rule becomes effective).  At this time, it’s impossible to tell what the reconsideration will do as many companies are looking to expand it. 
For liquid fuel-fired boilers, fabric filter may be an option.  We expect companies that installed a new baghouse would have used a BLDS since it appears to be preferred over a COMS.  We expect some companies will convert to natural gas instead of upgrading their solid and liquid-fired emissions controls.”

What specific problems do you find that companies have gaining compliance with regards to their baghouse?

“Opacity limits with short-averaging periods are a big problem for ESPs – almost any ESP on a solid fuel unit cannot run 100% compliance, though 99%+ is possible.  A baghouse can run essentially 100% compliance.  Since they all have COMS you record every hour.  PM CEMS are a big problem as their accuracy is suspect – back-to-back testing with Method 5 and a PM CEMS can give very different answers.

For the cement industry, the greatest challenge in meeting the new PM limits, other than the limits being low, is the related requirement to meet the limits with a PM CEM.  There is virtually no data of this type in the industry and the monitoring equipment is complex.  Therefore, there is significant uncertainty at to whether the limit is achievable, day in, day out. 

According to the Council of Industrial Boiler Owners (CIBO) the level of emission reduction for industrial-commercial-institutional boilers has not been demonstrated to be achievable by industrial applications, and may only be achievable on a consistent basis with the use of new technology not commonly used in industrial applications.  Electrostatic precipitator suppliers and bag house suppliers both indicate that this new standard is not achievable with the exception that the type of exotic filters used for clean rooms in food production and some pharmaceuticals may be applicable but at exorbitant cost.”

What aspect (or specific regulation or set of regulations) do you feel needs to be revised or reformed the most to make the regulatory process more conducive to industrial growth, while still providing protection for our environment?

“I believe EPA and state agencies need to revise or reform their dispersion modeling methodologies and/or tools to more realistically assess compliance with the new 1-hr NAAQS.”

Would you say that current regulation is hampering companies’ efforts to expand their operation?

“Yes.”

Advice for Companies

When working with a client to achieve overall compliance of their facility with applicable regulations, what advice or warnings do you give to them regarding the proper operation, and maintenance of their baghouse system?

“Periodic baghouse maintenance programs for many plants will need to be improved. There is a lot facility operators can do to make their baghouses run more efficiently.”

How important is it for plants to make sure their dust collection system is functioning properly?

“It will be very important to demonstrate continuous compliance with the more stringent regulatory requirements.”

Do you believe that it is in a facilities best interest to upgrade outdated and undersized dust collection equipment? In your experience (expert opinion) do you feel that it is worth the investment in capital for the potential benefits?

“Upgrade decisions will be required on a facility by facility basis but in many instances, upgrading of equipment will be necessary / required.”

What percentage of your clients would you say are having problems with their baghouse system that are causing them to be out of compliance with clean air regulations?

“By and large, our clients are in compliance with clean air regulations (continuous compliance is not an option for business risk mitigation).  However, the recent stringent regulations presents significant challenges and our clients are actively pursuing and developing solutions to implement in the next year or two.”

 

About Trinity Consultants: Founded in 1974, Trinity Consultants is an international firm that specializes in assisting industrial companies with air quality regulatory compliance challenges.  Trinity also provides professional training, environmental modeling software, EH&S information management solutions, and EH&S staffing services.  Environmental professionals can subscribe to Trinity’s free Environmental Quarterly publication at trinityconsultants.com/subscribe.

 

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Marketing Director at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

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More Reasons Not To Store Dust In Your Dust Collector Hopper

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Clogged machinery,  exposure to hazardous chemicals, and disruptions in plant processes,  are just a few of the problems that come from using your dust collector hopper for dust storage. 

February 25, 2012 | Baghouse.com News – One of the most common baghouse operation practices that we find when we send a dust collector technical advisor out to various facilities is that many plants unwisely use the hopper on their dust collector for storage of the collected dust. Sometimes this is done unwittingly, as maintenance staff simply overlook emptying the hopper on a regular basis. Other times, this is more or less included (unwisely), into the design by neglecting to install a discharge system, such as a screw conveyor, or slide gate mechanism.

Dust Collector Bags

“You dust collector is NOT designed to store collected material for extended periods of time.”

However, whether this course of action is planned or not, using your dust collector hopper for storage of any collected material for an extended period of time can cause a myriad of problems. Among the various problems that can arise are damage to dust collector bags, increased emissions, increased pressure drop (i.e. increased system airflow resistance), and clogging and damage to dust discharge systems (conveyor systems, slide gates, etc.).

In addition, in some instances involving compounds that may be considered hazardous, storing collected materials in the hopper can lead to extensive fines and prosecution from governmental regulators such as OSHA or the EPA.

A Foundry Runs Afoul of OSHA and The EPA, Lands President and Company in Criminal Court

Recently, a Franklin, New Hampshire metal parts manufacturer and its president pleaded guilty to charges stemming from what OSHA found to be unlawful storage of hazardous compounds. The hazardous or toxic compounds in question were byproducts of the plants manufacturing process, that contained high levels of lead and cadmium. The plant and its president according to court records, knowingly stored the waste with the hazardous levels of lead and cadmium in unapproved containers throughout the plant for longer than the 90 days allowed by law without notifying OSHA and the EPA.

During an inspection of the plant by OSHA in 2009, the plant was found to be in violation of the Resource Conservation and Recovery Act (RCRA), which requires a permit to store hazardous waste on site for longer than 90 days. OSHA notified the EPA of their findings, and then a few months later, the EPA executed a search warrant on the plant found drums of hazardous waste being stored at the plant.

In the end, a federal grand jury indicted Wiehl and Franklin Non-Ferrous Foundry for unlawfully accumulating and storing lead and cadmium hazardous waste at the foundry site since July 2005. Wiehl faces a possible maximum sentence of two years in prison and a maximum fine of $250,000. Under the terms of a plea agreement filed with the court, the United States Attorney’s Office has agreed to recommend that he serve two years of probation, six months of house arrest, and that he publish a public apology. Franklin Non-Ferrous Foundry, Inc is facing a possible maximum fine of $500,000.

Dust collection screw conveyer

Ensure your dust collection system regularly discharges into a dust conveyor system, such as a screw conveyor.

What’s The Lesson? Store Collected Dust Properly! 

While the situation with manufacturer discussed above did not involve storing material in the dust collector, it does demonstrate that the EPA, and OSHA (and other safety organizations) do not take kindly to the storing of chemicals and compounds in inappropriate ways. You dust collector is NOT designed to store collected material for extended periods of time. 

As already mentioned, using your hopper to store dust will lead to a score of problems that adversely affect not only the efficiency of your dust collection system, but your entire plant. These problems drastically increase if the collected dusts contain hazardous materials (lead, mercury, etc.), are an explosion hazard (food products, metal powders, fertilizer, etc.) or are corrosive to machinery. In these instances it is imperative that proper dust transportation, storage and disposal methods are implemented. These include the use of continuous hopper cleaning (such as timed or sense actuated slide gates, pneumatic locks, etc.). It is also vital to regularly check these systems, specially those components most prone to wear and failure such as slide gates, seals, etc.

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

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3 Cheap Ways to Increase Efficiency in Dust Collection Systems

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Dust collection systems are often overlooked when it comes to plant improvements due to the often high capital costs involved. We here at Baghouse.com have prepared this small list of improvements that can be made to your dust collection system with minimal investment. 

October 26th 2011 | Baghouse.com – Corporate executives are looking for any conceivable way to lower operating costs in our struggling economy, plant operators are being pushed by the corporate brass to find someway of doing more with less, and maintenance managers are trying to make sure all of these cutbacks do not compromise process operation. One area that many industrial plants can easily increase efficiency, and therefore lower operating costs is to look to their pulse jet baghouse dust collection systems.

Here are three small tweaks for your pulse jet dust collection system to increase operating efficiency without a major overhaul or great expense.

1. Ensure Filter Bags Are Installed Correctly
2. Install a Clean-On-Demand System
3. Integrate All System Controls (Clean-on-Demand, timer boards, manometers, etc.)

1. Correctly Install Filter Bags

Filter Bags are the heart and soul of a baghouse. If they are not installed correctly the entire system will suffer, efficiency will go down, filters will fail prematurely, system downtime will ensue and affect the entire process. Check that filters with flanges and cuff are folded over and smooth and not wrinkled around the cage to prevent leakage, and premature failure due to bag abrasion. Bottom-loading filters should be installed with seams 180° from the cage collar gap.

Snapband for dust collection systems

An example of how a snapband filter bag should be installed to maximize your dust collection system efficiency.

Additionally, there are several specific issues to watch out for depending on the exact design of filter bags being used. For snapband construction, check that the seams are set properly in the tubesheet. This can be done running your fingers along the edge of each bag during installation/maintenance checking that each one is smooth, with no wrinkles, gaps, or binds in the snapband. For designs with gaskets or rubber o-rings make sure these are not pinched by the clamps in a way that will allow leaks, or cause accelerated wear.

Additionally, with all bag types, all seams should be at a 45° angle from the aisle to minimize fraying due to increased can velocity, all clamps should be set 90° from the seams, and all filters need to be set properly in the cage groves.*

*Additional Tip: Have everything as uniform (clamps, seams, etc. all set in the same direction) as possible to make it easier to diagnose and remedy problems.

2. Clean-On-Demand System

Manually having a technician initiate the cleaning cycle for your dust collection systems can consume a large amount of time, and lead to less than desirable results such as over/under cleaning, operating at higher differential pressure (raising system resistance, and fan load), and lower collection efficiency. Simplify the process and remove the need to be a industrial filtration expert out of the equation by installing a clean-on-demand system.

Dust Collection Systems Timer Boards

Using a clean-on-demand timer board for your baghouse will simplify the cleaning process, and result in more effective cleaning of your dust collection system.

These systems are comprised of a differential pressure gauge, and a control board. The DP gauge monitors the difference in pressure between the clean-air and dirty-air sections of the baghouse (thus giving you the pressure drop over the filters at any given time). DP gauge is connected to the control board, which has a high and low pressure setting which serve as the start and stop markers for the system. When the DP in the baghouse rises past your high setting (indicating the bags need to be cleaned), the controller starts the pulse-jet cleaning cycle, once the pressure reaches the preset low, the pulse-jet system is disengaged.

For a relatively small capital investment clean-on-demand systems can dramatically improve your system efficiency by ensuring the minimum amount of cleaning cycles necessary are initiated, which in turn leads to lower compressed air usage, lower operating differential pressures, and less filter wear. These benefits will lower system operating maintenance costs, while seeing improvement in collection efficiency, and extended filter bag life.

3. Integrate Dust Collection System Controls

Maintaining the correct amount of dustcake on your filters is essential to achieve the maximum collection potential of your filter bags. In fact it is the dustcake itself that does the filtering in a baghouse, not the filter bags! * When the pulse-jet cleaning system engages, it removes the excess dust from the filter surface. Essentially what this does is rearrange the dustcake on the filters, removing a portion of it, and leaving behind the minimum amount needed to reform the dustcake for optimum efficiency. When cleaning cycles are carried out, if each row is pulsed one after another in sequential order, high internal air velocities between the filters (can velocity) can cause the recently dislodged dust to be redeposited on the recently cleaned bags in the previous rows. Since the dust is carried at higher than normal velocities, it can penetrate the fabric (instead of settling on top and forming part of the dustcake) and embed itself therein. This will eventually lead to filter blinding, and a reduction of filter service life.

Installing a sequential controller can help you avoid this problem. This device controls the order in which the bags are cleaned, staggering the cleaning pulse pattern between non-adjacent rows. For example, in a baghouse with 10 rows of bags, you can set the cleaning pattern to first clean rows 1,4,7,10 then 2,5,8, and finally, 3,6,9. You can also set the controller to only fire when the pressure in the compressed air header is at full, providing a consistent pulse force that will properly clean the bags every time. Additionally, to further promote longer filter life, see that each pulse duration is set as short as possible, generally around 0.1 sec.

If you do not currently have a DP clean-on-demand system, an alternative is to use a timer control to regulate system cleaning. When using a timer board setup, it is vital to set the intervals to match your system parameters, ensuring that the filters are neither over, or under cleaned. Maintaining a sufficient level of dustcake is vital to achieving a high system efficiency.

Finally, it is possible to integrate all of these different systems into one unified control panel for operator convenience. You can have all of your controllers relayed to a central LED controller, which then is connected to an external PLC controller or computer for remote monitoring, and recording of all system activity. From here it is then possible to configure all control parameters e.g. timer settings, clean-on-demand DP points, pulse-jet firing order, etc. Additionally, having all operating data in one convenient location will allow for quickly pinpointing problems before they become major issues.

*This does not apply to filter bags with membrane such as ePTFE. In that case, the membrane itself acts as a sort of permeant filter cake while surface dust provides no additional filtering.

Save Money By Increasing Dust Collection System Efficiency

These three tips are just a few of the many ways to increase the operating efficiency of your baghouse dust collection systems with only limited investment of time, material, and capital. Without a doubt, these improvements will pay for themselves many times over throughout the life of the system. At a time when new environmental regulations are requiring pollution control equipment to function at higher and higher efficiencies, not only will turing your attention to improving your dust collection systems lower your operating expenses, but it will also ensure that facilities stay in compliance and avoid costly fines and forced closures.

 

About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

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Filter Bags & Leak Testing – How Important is it?

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Filter Bags

Leak testing being performed in a Baghouse

By Dominick DalSanto
Environmental Technologies Expert & Author
Baghouse.com

Why Periodic Leak Testing of Filter Bags is Vital

Operating a dust collection system with leaking filter bags defeats its sole intended purpose. A few leaking filter bags or even one within a collector/system can result in a substantial emissions increase. Leak testing of your Baghouse filter bags needs to be a regular part of any maintenance program to ensure system efficiency, and maintain compliance with emissions/safety regulations and avoid the fines and/or safety hazards that come with it.

All filter bags will eventually wear all out and need to be replaced. Baghouse maintenance programs should include periodic leak testing to ensure a few or even one faulty bag does not reduce the operating efficiency of the entire system. On occasion, a defective filter will fail early and need to be replaced. In other instances there may be a temporary or unanticipated event that can cause of premature failure of Baghouse filter bags. Once identified these should be investigated to ensure the incident does not occur again, and determine the extent of the damage done to the system. Examples may include: abrasion, thermal durability, and chemical attack.

  • Abrasion from several different sources often leads to excessive wear (and therefore premature failure) of the filter bags. The most obvious is caused by excessive particulate loads in the gas stream. This may have been caused by the unexpected failure, or shutdown/maintenance of a pre-filter (such as a cyclone, or air scrubber for NOx and SOx). Poor design may also lead to particulate laden air striking the filters in certain spots more than others such as near the cuff, or dirty-air inlet. Other sources of abrasion damage include: improperly installed filters that rub against each other, and excessive cleaning cycles.
  • Degradation of the filter bags’ Thermal Durability may also be a potential cause of early failure. When operating temperatures that rise above the designed limits of the fabric, whether for short or long term, filters will begin to degrade and eventually fail. Changes in the plant process, fuel source, maintenance shutdowns of other systems, etc…may result in temperature spikes that will irreparably damage Baghouse filters.
  • Chemical attacks can also result in bag failure. These can occur when gas stream characteristics are not taken into consideration when selecting the filter fabric and/or treatments/finishes. Other times unexpected changes occur in the gas stream that cause changes in the composition of the gas. Operating temperatures may also fluctuate,  dropping below the dew point allowing condensation of the chemicals on the fabric.

Filter Bag Leak Testing – How it is Done

To perform a standard leak test several things need to be done before the actual test can take place. First, since testing requires temporary isolation from the facility process, and shutdown, you must determine the best time for each unit and/or compartment to be tested. Second, safety measures for plant personnel must be taken into account when estimating total down time. Units must be given sufficient time for cooling, atmospheric testing to check for harmful gases, and personnel assigned to perform both the test and fulfill any and all safety regulations regarding confined space entry (both OSHA, and In-house). Once the preliminary steps have been taken, the actual testing can begin.

Filter Bags - Leak Testing

A vital part of any Baghouse system maintenance plan is regular leak testing of the filter bags.

First, florescent leak detection powder is added upstream of the unit such as at a maintenance access in the ductwork. Then after sufficient time has past for the powder to work its way through the system, the unit is shutdown. Once it is possible, a technician will enter into the unit with a UV light source i.e. a black light to examine the filter bags for leaks. The powder fluoresces under the UV light, thereby making it easy for the technician to see even the smallest of holes. The technician makes note of any faulty filters, which can then be replaced.

Regular Maintenance is Key to Getting the Highest Efficiency from Your Baghouse

Baghouse systems are the most efficient, and cost effective solution for particulate matter control in industrial settings – but only if they are maintained properly. A vital part of any Baghouse system maintenance program is regular leak testing of the filter bags. By conducting this and other maintenance tasks, your Baghouse system will operate smoothly, and provide the best of results.

Looking for Leak Testing Services?

Baghouse.com has the expertize to locate and remedy leaks in not only your filters, but also duct work, collector housing, and more. To learn more about Baghouse.com leak testing services and leak testing supplies or receive a free quote on Baghouse leak testing please contact us for a free quote.

 

 

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How to Choose the Correct Baghouse Filter

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Often our customers find it difficult to determine exactly what kind of Filter Media they require for their specific Dust collection system. Other times they know the particular type of filter media they need, but are unable to determine the exact size they need for their Baghouse.

To assist our customers, we at Baghouse.com have prepared this article to help you select the right filter media to match your specific needs.

If you would like to speak directly with one of our dust collection experts for additional help in selecting your Filter Media, or if you would like to receive a free Baghouse Filters quote, please call us at  800 351 6200 or Contact Us using our online form.

 

Step 1 – Filter Media Selection

Choose the media from which your filter bags will be constructed of based on the type of application they will be used for. Take the following things into consideration prior to selecting your filter media:

•    Temperature – Do your bags need to withstand extreme temperatures?
•    Material – What is the filter being used for?
•    Chemistry – Can your filter withstand the chemical makeup of the dust particles
•    Resistance- Is the filter media able to resist the abrasion of the dust particles

Choosing the correct filter media is an important and sometimes difficult process. To assist you in the identification of the right media for your bags, keep the following in mind: 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 its ability to be cleaned by the dust collector is also important. You must first learn to identify the type of filter media currently used in your application. Below you will find a list of typical construction methods:

•    Woven felts
•    Non-woven felts
•    Natural fibers
•    Synthetics (Thermoset or Thermoplastics such as Polypropylene “PPRO” – Polyphenylene sulfide “PPS” – Polyester “PE”)

For additional information on media types please examine our Filter Fabrics Chart below. 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. The selection criterion eliminates materials based on temperature and chemical characteristics. The first cut is usually made based on temperature. Then the chemical characteristics of the gas stream are considered to further refine the search. Next, the efficiency of the material further dictates the construction of the material such as the weight, oz/sq. ft., fiber and surface treatments/membranes. Last but not least, if there are still two or more candidates it comes down to a price versus performance trade off.

Dust Collector Filter Fabrics

 

Popular Materials

 

Polyester FeltPolyester Felt - Baghouse Filter Fabric

Recommended continuous operation temperature: 275°F
Maximum (short time) operation temperature: 300°F
Supports combustion: Yes
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Fair
Resistance to mineral acids: Fair+
Resistance to organic acids: Fair
Resistance to oxidizing agents: Good
Resistance to organic solvents: Good
Available weights: 10 oz. – 22 oz.

Polypropylene Felt - Dust Collector Filter Fabric

Polypropylene Felt

Polypropylene Felt

Recommended continuous operation temperature: 190°F
Maximum (short time) operation temperature: 210°F
Supports combustion: Yes
Biological resistance (bacteria, mildew): Excellent
Resistance to alkalis: Excellent
Resistance to mineral acids: Excellent
Resistance to organic acids: Excellent
Resistance to oxidizing agents: Good
Resistance to organic solvents: Excellent
Available weights: 12 oz. – 18 oz

 

High Temperature Materials

 

Conex® / Nomex® Felt (Aramid) - Dust Collector Filter Fabric

Conex® / Nomex® Felt (Aramid)

Conex® / Nomex® Felt (Aramid)

Recommended continuous operation temperature: 400°F
Maximum (short time) operation temperature: 425°F
Supports combustion: No
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Good
Resistance to mineral acids: Fair
Resistance to organic acids: Fair+
Resistance to oxidizing agents: Poor
Resistance to organic solvents: Good
Available weights: 10 oz. – 22 oz.

P84® Felt Polyimide - Dust Collector Filter Fabric

P84® Felt Polyimide

P84® Felt Polyimide

Recommended continuous operation temperature: 475°F
Maximum (short time) operation temperature:500°F
Supports combustion: No
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Fair
Resistance to mineral acids: Good+
Resistance to organic acids: Good+
Resistance to oxidizing agents: Good+
Resistance to organic solvents: Excellent
Available weights: 14 oz. – 18 oz.

Ryton® Felt / PPS - Dust Collector Filter Fabric

Ryton® Felt / PPS

Ryton® Felt / PPS

Recommended continuous operation temperature: 375°F
Maximum (short time) operation temperature: 400°F
Supports combustion: No
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Excellent
Resistance to mineral acids: Excellent
Resistance to organic acids: Excellent
Resistance to oxidizing agents: Fair
Resistance to organic solvents: Excellent
Available weights: 16 oz. – 18 oz.

Dust Collector Filter Specialty Materials

 

Homopolymer Acrylic Felt - Dust Collector Filter Fabric

Homopolymer Acrylic Felt

Homopolymer Acrylic Felt

Recommended continuous operation temperature: 250°F
Maximum (short time) operation temperature: 275°F
Supports combustion: Yes
Biological resistance (bacteria, mildew): Good+
Resistance to alkalis: Fair
Resistance to mineral acids: Good+
Resistance to organic acids: Excellent
Resistance to oxidizing agents: Good
Resistance to organic solvents: Good+
Available weights: 15 oz. – 18 oz.

Epitropic Felt Antistatic - Dust Collector Filter Fabric

Epitropic Felt Antistatic

Epitropic Felt Antistatic

Recommended continuous operation temperature: 275°F
Maximum (short time) operation temperature: 300°F
Supports combustion: Yes
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Fair
Resistance to mineral acids: Fair+
Resistance to organic acids: Fair
Resistance to oxidizing agents: Good
Resistance to organic solvents: Good
Available weights: 14 oz. – 16 oz.

Step 2 – Dust Collector Filter Measurements

Accurate measurements lead to the best fit. It’s likely that your dust collector has been modified over the years due to permitting issues or changes in your process which called for a reconfiguration of the Baghouse. In this case OEM configurations will not fit and you will need to obtain accurate measurements for your filters before ordering replacement filter bags. If you currently have filter bags installed that are functioning properly, you can remove one of these bags to get the proper measurements for your replacement order. A spare bag that has not been used yet can also be measured if available. However, be sure to verify the bag measured is the same as the bags currently being used in the dust collector. If you are removing a used bag to measure, please be sure to use all necessary precautionary measures set in place prior to removal i.e. gloves, protective garments and respiratory equipment if needed. It is best not to rely only on the numbers off the unit of OEM filter specifications because of possible changes to the configurations. Of course the best solution is to mail the manufacturer a new or used bag that can be used a guide sample.

Flat Width: Place the filter on a flat surface such as a large table or cement floor. With the filter stretched out, press down on the side. Using a measuring tape, very accurately record the width. Be sure to hold the filter down firmly on an even surface when taking this measurement.

Diameter: When measuring the tube sheet hole of a pulse jet style dust collector, first make sure the hole has not been damaged or warped in any way. Clean the surface thoroughly with a wire brush then using a micrometer, measure the hole in both directions. If the measurements are at all different locate another hold and repeat this process.

Length: Remove the filter from the unit. Preferably with the assistance of another person, stretch the filter out. While maintaining tension on the filter record the length from the longest point at each end using a measuring tape. Do not include and straps, metal caps or other hanging hardware in the measurement, just the length of the filter itself.

Step 3 – Top & Bottom Construction

The top and bottom construction of a filter bag involves a variety of possible configurations. Identifying the type of cleaning process used by your dust collector will help to determine which configuration is needed. The most common types of dust collectors are “Pulse-Jet” “Shaker” “Reverse Air”. The chart below can help you identify which type of dust collector filter you are using.

Filter Configuration Chart

Pulse-Jet Dust Collectors (Reverse jet) – Found in almost every industrial environment. They are the most popular design and are seen in nearly all industry segments. Pulse-Jet Units can be divided into two major groups Top load or bottom load units sometime called top entry (walk-in plenum) or bottom entry (common in bin vents) because of the point of entry used to change out the filters.

Typical filter configuration for a top load unit:
Snap Band Top (double-beaded ring)
Disk Bottom (w/o wear strip)

Typical filter configuration for a bottom load unit:
Raw End Top
Disk Bottom (w/o wear strip)

Shaker Dust Collectors (Mechanical Cleaning) – Usually found in older applications where unscheduled down time is not a major concern.

Typical filter Top Configurations
Loop Top
Grommet Top
Strap or Tail Top
Metal Hanger or Cap

Typical Filter Bottom Configurations
Corded Cuff with Clamp
Snap Band (Double-Beaded Ring)

Reverse-Air Dust Collectors – Usually found in very large air handling environments such as power generation and cement plants although they do have uses in a variety of industries. Sometimes called a structural bag, these filters usually have a series of support rings spaced every few feet throughout the length of the bag.

Typical Top Configurations
Compression band w/Metal Cap & Hook

Typical Bottom Configurations
Compression band
Snap Band
Cord w/Metal Clamp

Snap Band - Dust Collector Filter Configuration

Snap Band

Raw Edge - Dust Collector Filter Configuration

Raw Edge

Cord - Dust Collector Filter Configuration

Cord

Hanger - Dust Collector Filter Configuration

Hanger

Grommet - Dust Collector Filter Configuration

Grommet

Loop - Dust Collector Filter Configuration

Loop

Strap - Dust Collector Filter Configuration

Strap

Support Ring - Dust Collector Filter Configuration

Support Ring

Rubber O-Ring - Dust Collector Filter Configuration

Rubber O-Ring

Disk - Dust Collector Filter Configuration

Disk

Disk With Wear Strip - Dust Collector Filter Configuration

Disk With Wear Strip

Flange - Dust Collector Filter Configuration

Flange

Hem - Dust Collector Filter Configuration

Hem

Sewn Flat - Dust Collector Filter Configuration

Sewn Flat

Envelope - Dust Collector Filter Configuration

Envelope

Step 4 – Additional Options

Ground Wires – Use to comply with Factory Mutual requirements for static dissipation. Ground wire can be made from stainless steel or copper however this technique only works on a localized area of the filter. For optimal static dissipation look at conductive fiber filter made with Epitropic or Stainless Steel fibers.

Wear Cuffs – Used to combat abrasion at the bottom of the bag either from a sandblasting effect or from bag-to-bag abrasion due to turbulence in the bag house. Usually 2 to 4 inches in length and made of a material similar to that of the body of the filter bag.

Special Finishes – There are many finish options that can be added to the filter media at the time it is manufactured. Please refer to the materials selection area for further details. If you want to order a specific brand or special type of finish please add that request into the additional comments section when ordering.

 

 
About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

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