A video introduction to the Baghouse.com Guide for Sizing and Designing your Dust Collection System

Hi, and welcome to our guide for how to properly size and design your dust collection system.

This guide is going to help you to avoid some of the more common pitfalls we see with sizing a dust collection system. For example, many dust collector OEM’s and sales rep organizations will frequently undersize their systems in order to beat the lowest price in any bidding competition. But then later on, once installed, they don’t perform adequately.

Our guide’s going to help you to calculate the approximate size and determine an adequate system configuration that will meet your application and process needs, which you can then use when comparing quotes from various manufacturers. Our guide’s also going to provide information that will be helpful for general baghouse maintenance, operation, as well as safety procedures.

If you have any questions, please, feel free to contact us for more information.

An image of the worn-out cuff of a baghouse filter

The regular operational life of a baghouse filter can be shortened by a number of factors. In this article we will discuss the top 4 reasons:

  1. Abrasion
  2. Exceeding Maximum Operating Temperature
  3. Chemical Attack
  4. Fire

1. Abrasion

The deterioration of filter bags through abrasion can be a result of a number of causes.  It can be caused by bags physically rubbing against each other, from the type of cleaning mechanism used or from where the dust enters the bag and impacts the fabric. The most common is caused by excessive particulate loads in the gas stream. Poor inlet design may lead to particulate laden air striking the filters in certain spots more than others such as near the bottom cuff, or strike the filters closest to the dirty-air inlet. In shaker baghouses, bags can deteriorate prematurely due to vigorous shaking particularly at points where the bags are attached. In pulse jet baghouses  the repeated rubbing of the bags against the support cages (especially if the cages are bent or rusty) can considerably shorten the working life of the baghouse filter. This is usually the case when the filters are not sized properly to the cage (otherwise known as the correct amount of “pinch”). 

“A properly designed, installed and maintained system can go a long way in preventing premature baghouse filter failure…”

2. Exceeding Maximum Operating Temperature

An image of dust that's collecting inside of a baghouse
Is your baghouse building up dust?

Baghouse filters are manufactured using various materials depending on the application they are being used for. These materials have different thermal durability, that is the upper temperature limit of the fabric. Thermal durability may also be a potential cause of early failure. When operating temperatures rise above the designed limits of the fabric, whether for short spikes or longer overages, filters will begin to degrade and eventually fail. This may be a sudden failure such as the filters melting or catching fire or it could result in less obvious damage that causes the bags to become brittle. Changes in the plant process, fuel source, maintenance shutdowns of other systems, etc., may result in temperature spikes that will irreparably damage the filters. 

3. Chemical Attack

Baghouse filter failure can also occur from a chemical attack. In its simplest form, this can be caused by using the wrong fabric for the chemical makeup of the gas stream. If gas stream characteristics are not taken into consideration when selecting the filter fabric and/or treatments/finishes, chemical attack can cause considerable damage to the baghouse filter.  Other times unexpected changes occur in the gas stream that can cause changes in the composition of the gas. For example, operating temperatures may drop below the dew point allowing chemicals in the gas stream to condense on the filters. This can have a dramatic effect on the life span of a baghouse filter, therefore proper fabric selection and maintain tight control over the process operating conditions and procedures can help eliminate bag deterioration caused by chemical attack.

4. Fire

An image of a baghouse filter that's been damaged by fire.
A dust collection filter damaged from fire.

Premature baghouse filter failure can also be caused by fire. This could range from a relatively mild occurrence to a far more serious event. A minor event could be caused by an ember or a spark entering the baghouse system. The ignition source can then be drawn through baghouse system and make make its way to the surface of the filter causing a hole to be burnt in the bag or for it to catch fire.

Additionally, if the dust collection system is not working properly dust accumulations may form that can then provide fuel for a potential fire or explosion. If then a spark or ember enters the system this built up dust can ignite causing a fire, which can then be dragged through the entire system causing a serious or even catastrophic conflagration. This often happens when a system is choked off with high pressure drop (differential pressure) across the filters or when the dust discharge system (baghouse airlock and any connected screw/pneumatic conveyors downstream) do not remove the dust from the baghouse quickly enough.

Prevention

A properly designed, installed and maintained system can go a long way in preventing premature baghouse filter failure. Following a regular preventative maintenance provided by a reputable dust collector OEM like Baghouse.com can keep your system in good working order. At times a dye leak test among other things can help technicians identify the exact cause of early filter failure.

Need Help Ordering Baghouse Filters?

Whether you know exactly what you want or could use some help getting the right dust collection filter, we’ll put together a free quote with the perfect filter for you.

A entry level triboelectric broken bag detection system - Courtesy of http://auburnsys.com/

By Dominick DalSanto
Baghouse.com

Quickly finding and replacing leaking filters is crucial for keeping a baghouse operating at peak efficiency. The longer you take to replace the leaking filter the more likely you will have to report the event to your air quality control regulatory agency (reportable event) and the more abatement costs you will incur.

How Broken Bag Detectors Work

How Triboelectric Dust Detection Systems Work

How triboelectric bag leak detection systems work – Courtesy of http://auburnsys.com/

Triboelectric broken bag detectors measure the amount of static electricity generated by dust particles in an airstream. Dust particles generate an electrical current when they encounter the insulated metal probe in the ductwork. A dust particle directly impacting the probe creates a DC signal while a particle passing near to the probe generates an AC signal. The latest generation of triboelectric detectors (such as the Auburn Systems’ TRIBO series) unify both signals and then output a measurement of particle concentration to a nearby control panel or transmit it to a PLC.

Using a Triboelectric Broken Bag Detector as Early Warning

Most leaking baghouse filters begin as small holes or rips that overtime become worse and worse. Catching a leak quickly is crucial. The longer a leak persists the worse it becomes, often quickly causing a plant to exceed its maximum PM 2.5 emissions limits set out in its air permit. Additionally, abatement requirements quickly increase as a leak continues over time.

Older optical emissions monitors (i.e. opacity meters) and optical bag leak detectors can only detect a filter leaking so badly damaged that the increase in emissions exceeds 10% opacity (often greater than the maximum permissible levels for many air permits).

Triboelectric systems are sensitive enough to detect even the smallest of increases in dust emissions such as when a bag first begins leaking. Operators can then examine the realtime trending emissions data to see whether it was a sudden spike indicates a damaged bag (such as from quickly worn hole) or slow rise indicating wearing filters.

 

Using Broken Bag Detector to Pinpoint Which Filters Are Leaking

An added advantage of triboelectric bag leak detectors is they can enable operators and maintenance technicians to pinpoint exactly which bags are leaking and need to be replaced.

Personnel should carefully monitoring emissions while cleaning system runs. When emissions spike during one cleaning cycle it means that leaking filters are present. Using this method, maintenance personnel can trace the leaking filters down to a specific baghouse, compartment and even row (pulse jet only) of bags. This saves time and money over traditional dye leak testing.

However, on older units, or when first beginning to troubleshoot a unit dye leak testing should still form part of your maintenance schedule. Dye leak testing can pinpoint multiple leaks at once, and in structural components as well as filters.

By quickly pinpointing leaking filters maintenance staff also reduce the amount of abatement required after the leak is fixed.

Below is the sample data from a test conducted to determine the differences in performance between a triboelectric leak detection system and a typical optical system (opacity meter). Notice the huge difference in response time and abatement required.

Leak Test ResultsTriboelectric Bag Leak DetectorOptical System
Estimated Time to:
Detect LeakLess than 1 Hour2-3 days
Locate Leaking Filter(s)Less than 1 Minute2-3 Man Hours (dye leak test)
Clean Up LeakLess than 1 Man-Hour8-10 Man Hours
Estimated Size of:
Hole Detected1/4”8”
Dust Accumulation2.6 cubic feet60 cubic feet
Dust Clean Up ToolShopvacShovels

Source: https://cdn2.hubspot.net/hubfs/354686/BrandBuilder%20Solutions/Case%20Studies/Aluminum_Case_Study.pdf

Reduce Baghouse System Downtime

When a baghouse goes down it often brings much down with it, from specific equipment to entire production lines to even entire plants due to emissions or health and safety issues. Preventing unscheduled baghouse shutdowns directly impacts the bottom line. In some facilities, losses from just one down day can add up to tens of thousands of dollars in lost production, fines and other costs. Therefore, investing in the maintenance and upkeep of these baghouse systems is well worth the initial capital costs.

Triboelectric dust monitoring system often prove one of the most cost-effect ways to improve dust collector maintenance and operation. With the ability to monitor emissions in realtime and trends over time, operators can better assess the condition and operation of their baghouses than those who rely solely on differential pressure.

For example, by carefully analyzing the triboelectric data trends maintenance planners can accurately predict when filters will no longer achieve their require collection efficiency and need a changeout. Further, they can begin preparations for the changeout in advance, sourcing filters and cages, obtaining contract labor for the changeout and scheduling the changeout for the next most convenient time (e.g. yearly maintenance shutdown). Compare this with the added costs and stress involved when a changeout is done at the last minute!

Additionally, as mentioned above, triboelectric bag leak detectors also prevent downtime by quickly alerting plant personnel to any leaks as soon as they begin to form. By catching leaks before they become serious plants can avoid stoppages for abatement, repair and any possible fines or sanctions from air quality regulators.

Recap of the Key Points

  • Triboelectric bag leak detectors directly impact the bottom line of your baghouse by improving maintenance efficiency, reducing downtime
  • Increased detection range means finding leaks quicker, before they become reportable events
  • See when filters first begin to fail allows predictive maintenance planning to reduce inconvenient shutdowns
  • Find leaking filter bags quicker, pinpoint down to specific unit, compartment and row without a dye leak test
  • Comply with MACT standards that require triboelectric broken bag detectors over opacity meters

Interested in a Triboelectric Broken Bag Detection System?

If you would like to know more about our line of triboelectric broken bag detectors  and how they can benefit your facility contact us today for a free consultation and quote!

Baghouse maintenance from Baghouse.com personnel
PTFE membrane on a baghouse filter under a microscope

Yes, there is a difference between the two. One is used to increase collection efficiency and one is used primarily for protecting the filter bags from chemical attack.

What Are PTFE Membrane Filter Bags?

PTFE membrane is semi-porous layer of PTFE bonded to the surface of a filter. This membrane acts at a permanent dustcake, capturing incoming dust particles (i.e. particulate matter or PM 2.5) on the surface of the filter (surface filtration) as opposed to normal filters that require a thick layer of dust buildup (dustcake) to actually reach peak efficiency. This means that PTFE membrane bags can operate at peak collection efficiency from the moment they are installed, and do not need to be precoated. Overtime, the membrane also works against the dust penetrating deep into the depth of the filter fabric, which is the cause of filter blinding. For this reason, PTFE membrane bags often last considerably longer than standard filter bags and have a more consistent differential pressure over time.

PTFE membrane on a baghouse filter under a microscope

PTFE membrane is a thin layer of PTFE laminated to the surface of a filter bag. It captures dust on the surface of the filter and easily releases the dust when pulsed.

PTFE Baghouse filters with PTFE membrane have the highest collection efficiency of all filters in production today. Bags using membrane technology can collect particulate matter down to 2.5 microns in size at over 99.99% efficiency. (In laboratory testing one OEM’s PTFE filters had 0.00% detectable emissions in the test rig). For this reason, in the applications with very tight emissions requirements, PTFE membrane filters are the standard.

Membrane bags are not recommended for a few limited applications, usually involving oils and hydrocarbons are these can close off the pores of the membrane and cause the filter to plug up.

What Are Filter Bags with PTFE Finish or Treatment?

In this use of PTFE, rather than creating a surface layer or membrane on top of the filter, the filter fabric is coated in a bath or spray of liquid polytetrafluoroethylene (PTFE) resin. This is done to protect the filter. The treatment improves the flex life, heat and chemical resistance and dust release from the fabric. This increases the service life and efficiency of the filters. PTFE finish is commonly used in applications with corrosive chemical compounds, sticky dusts, or high moisture contents.

Would you like to learn how PTFE membrane filter bags can improve your dust collector operation and save you money? Contact us today to find out more!

A Baghouse filter with PTFE (Teflon) Membrane

PTFE membrane or PTFE finish can be applied to a baghouse filter made from any fabric, such as fiberglass, polyester, or aramid (Nomex). It can even be used with pleated filters or cartridges.

Bent and rusted dust collector filter cages

The answer is that it depends…In many applications it is possible to reuse the cages once or possibly more. But in many other applications it may not be wise to reuse the cages.

Damaged Baghouse Cages From Corrosion and Mishandling

The main two types of cage damage we see are physical damage (bending, breaking, warping, etc.) and corrosion. Cages frequently get bent or broken by maintenance personnel over time by handling during changeouts and maintenance work. Other times, cages are damaged when stacked on top of each other for storage.  Additionally, fires or temperature excursions can warp cages.

Rip in a baghouse filter caused by a broken support cageCorrosion can occur from chemical attacks (e.g. acid flashes,) or upset conditions within the system. In some applications, high moisture levels can promote corrosion of the metal cages very quickly. And sometimes cages are stored outside uncovered  and left exposed to the elements.

Reusing Damaged Cages Will Cause Your Baghouse Filters To Fail Sooner!

There are three ways damaged or corroded cages cause filters to fail:

A bent baghouse cage has worn holes in the filter.

Bent or warped cages can eventually wear holes through your bags and cause massive leaks.Using damaged or corroded cages along with new baghouse filters will damage your filters and lead them to fail. This means you will experience leaks or even total filter failure much quicker than normal. Such failures can have high costs in terms of maintenance, possible system shutdowns, lost production as well as the costs of buying replacement filters sooner than normal.

  • When pulsed bent cages can cause the filters to rub against each other or against the sides of the collector causing the bags to tear open
  • Bent, twisted, or broken cages will have many sharp edges that can cut holes in the fabric very quickly when pulsed
  • Rusted or corroded cages will eat through the bag fabric and very quickly cause holes to appear.

In applications with very corrosive environment
(acid/alkali compounds, high humidity, condensation, etc.) such as foundries, dryers, chemical processing, etc., it is essential to avoid reusing cages that are damaged or corroded.

Even in applications with milder environments, the frequent handling of cages during repeated changeouts will eventually result in damage to the cages. Using cages in good condition extends filter life and improves efficiency by preventing:

  • Tearing or cutting filter on sharp edges
  • Damage from abrasion from other bags or unit
  • Corrosion eating through the fabric on the bags (Consider investing in galvanized, epoxy-coated or stainless steel cages to improve resistance to corrosion
  • Ineffective cleaning by ensuring the bags are properly fitted to the cages (Bags need to fit correctly
    across entire cage in order to get the required snap back when pulsed with air…not possible with bent cages

Reusing Damaged Cages Can Cost You Dearly

Bent and rusted dust collector filter cages

Corroded (rusted) cages will lead to early bag failure. Avoid reusing cages if they are damaged or corroded in any way.

Even minor rips, holes, and tears in the bags can lead to exceeding emissions limits. In many plants, such a problem will cause an emissions spike, becoming a “reportable event”, with possible fines and sanctions from regulators as a consequence. Additionally, any baghouse malfunction has the potential for causing plant-wide problems, that may lead to shutdowns, production losses and other costs far in excess of replacing the cages.
You can avoid all these problems and more by not using damaged or corroded cages in your baghouse. Additionally, if you keep spare cages on site at your facility make sure to store them where they are protected from corrosion and avoid stacking to many rows on top of another to prevent bending.

Baghouse Filter Cage Styles

Do you have corroded or bent cages in your baghouse? Let us give you a quote today for new cages along with your next set of replacement filters and receive a discount on both! Contact us now for a free quote.

Large backdraft workstation vented to dust collector by ductwork

Dust collector OEMs constantly try to come in with bids lower than competitors. In an attempt to do so, some baghouse manufacturers offer undersized systems. This article discusses what customers can do to avoid accepting a bid for an inadequately-sized baghouse dust collection system.

By Dominick DalSanto
Dust Collection Expert & Sales Director
Baghouse.com

”I’m sorry, but the other supplier came in lower than you. We went with their proposal over yours.”

I think there are few things I hate hearing more than those words in my position in baghouse sales. I can respect a client who has found a better deal on a comparable system. But I am upset when I hear that my competition came in with a bid lower than mine by recommending a grossly undersized system. As a sales professional, this particularly exasperates me as I feel these OEMs abuse the level of trust placed in them by the customer by offering something they know will not work properly — and because I know how big a problem it is in our industry.

Many sales reps apparently believe in the viability of their plans, and, thus, offer them in good faith, but others have — and will — propose systems that are smaller than customers require knowing that it will not perform adequately. The end result is that vital baghouse systems do not operate adequately, and customers, workers, and the community end up paying the price in the form of higher operating costs, safety hazards, and more pollutants.

The situation can present a major problem for customers as most of them rely on the experience and expertise of baghouse manufacturers or environmental technology experts to recommend a properly sized system. Lacking knowledge on dust collection engineering and industry best practice, customers must rely on others without being able to independently verify their figures.

The question this arises, how can customers prevent this from happening?

Baghouse Case Study at Silver Mine Lab

View of entire testing area equipped with a dust collection system

View of entire testing area including the various hoods and backdraft table connected to a dust collection system.

A few years ago, a silver mining operation contacted us and requested a technical inspection of one of the mine’s baghouse dust collection systems. The task was to examine a small 5,000 cfm system used for venting an onsite testing lab. In the lab, plant personnel conducted daily tests of ore samples taken from various locations in the mine to ascertain which areas had the highest concentrations of silver ore. The process for conducting these tests involved the use of several extremely harmful substances, chiefly lead and cyanide.The main concern was that during some recent evaluations for safety purposes, lead dust had been found on windowsills and in nearby rooms. Additionally, the amount of lead dust found on the clothing of workers in these areas — specifically lab technicians — was found to be several times higher than allowable under MSA standards, leading to one worker requesting a transfer to a different department. In addition, the system itself appeared to function at a very low level of efficiency and “did not seem to run properly,” according to staff.

Problem — An Undersized Baghouse System

Large backdraft workstation vented to dust collector by ductwork

Backdraft workstation – Draft (i.e. suction) on the table was so weak it could hardly contain any dust generated on the table

After conducting an inspection and reviewing several elements of the system, I immediately realized it was grossly undersized. It was “designed” to ventilate the testing lab using a series of venting hoods and vented workstations. There were five pickup points in the system that were connected directly to the baghouse, which was located just outside the exterior wall. The first drop point was a large backdraft workstation (Picture  #2), 72 in. x 36 in., for mixing the lead and other compounds together with the ore samples. There were three small furnaces — used to heat samples — with venting hoods of 32 in. x 39 in. above them. And there was one tall, ducted workstation, 32 in. x 39 in., used as a back-up for the other mixing station. Venting for everything went straight up through the ceiling to the main trunk (Picture #3), which then ran directly out through the exterior wall and into the baghouse. The main trunk was 12 in. in diameter, tapering to 10 in. then 8 in. then 6 in. The main workstation was connected using a 10 in. duct, and all others used a 5-in. duct (Picture #4) to connect the hoods to the main trunk.

Dust collection system ductwork above the ceiling of the testing room

The ductwork above the ceiling of the testing room. The size of the individual branches and the way they connect to each other was not designed according to industry best practice

According to the supplier-provided specifications, the baghouse had (49) 5.5 in. x 10 in. bags, and the system fan was rated for 5,043 cfm at approximately 10 in. w.g. of pressure. In this arrangement, the system should have resulted in an air-to-cloth ratio of approximately 7.15:1.

After manually taking airflow readings, I found that the system cfm actually was 3,969. Additionally, when we physically removed a sample bag and measured it, we found it to be 5 in. in diameter, not 5.5 in. as the spec sheet listed. After crunching the numbers, we determined that the air velocity was, at times, below 79 ft./m. This was less than one-50th of the minimum recommend air velocity for this application.

Venting hood connected to a dust collection system

One of the hoods over a test furnace. Notice the lack of curtains and small diameter duct going up out of the hood.

Poor ductwork design, a grossly undersized baghouse, and an equally underpowered fan combined to make this system almost worthless to the facility. (they neglected to size the fan based on the relative elevation and in doing reduced the output of the already undersized fan by another 30%) The effective pull from the system was so weak that one could place a hand directly under the intake on any of the stations and feel almost no noticeable suction — even when the system was running at full power. It was so weak it could hardly lift a piece of paper out of my hand! Obviously, this led to the excessive contamination of the workers and surrounding area.

Why So Small?

The system was designed by in-house personnel, who had no air-handling engineering experience, and a testing lab consulting company. The consultant procured the system from a sales rep organization, which, in turn, procured it from another independent sales rep that worked with the manufacturer. The final cost of the system was more than $75,000 for the baghouse, fan, ductwork, and hoods — much of that being mark-up for all the parties involved. The system was undersized from the start, so while cheaper for the customer, it ended up virtually useless for that customer.

Using even rough calculations, with a minimum conveying velocity of 250 ft./m in the hoods — and that really should have been even higher — the system would have required at least 12,000 cfm to function at an adequate level. Heavy dusts such as lead require high conveying velocities between 4,000 ft/min or more to prevent product drop out. This would mean a much larger system fan, (adjusted to the 4,400-foot geographic elevation of the plant), a baghouse with either triple the amount of bag filters or the use of pleated filter elements to increase filter area, and a completely redesigned ductwork system with a larger trunk and branches, along with better hood design and a damper system to further increase collection efficiency.

Solution — How to Avoid Being Sold an Undersized System

Some may feel that this case study serves only as a horror story to scare potential buyers on the pitfalls of trusting unscrupulous salespeople. I agree that part of the reason for telling this story is to advise you that implicitly trusting any vendor trying to sell you something as large and expensive as a dust collection system is not wise. The main moral of the story, however, is to help you make sure you get the best dust collection system for your needs. In the previously outlined case study, the following steps may have helped prevent this disaster:

1) The first step is to do your homework before you call for quotes. While becoming an expert on every piece of industrial equipment before contacting vendors isn’t feasible, gaining as much knowledge as possible goes a long way to ensuring you get what you need. Knowledge provides you with leverage during the sales process. Since, in this case, company personnel went in completely ignorant of how a dust collection system operates, they were at the mercy of whatever their vendor was going to tell them. This meant they had no idea of air-to-cloth ratios, air conveying velocities, ductwork design, etc.Additionally, where possible, deal directly with a baghouse dust collector manufacture (such as Baghouse.com) as opposed to sales rep organizations, that often have little to no practice experience engineering dust collection solutions.

2) Second, verify vendor calculations. While at times you may be able to determine exactly what size a system you need on your own, you may require assistance. This is especially true with regard to new installations and new processes. There is nothing wrong with asking vendors to assist you, but make sure to review their numbers afterward. This may require a bit of research or even hiring an outside consultant to verify the engineering. In the case study, had plant personnel taken the time to review system specifications proposed by the vendor, people would have found that the figures were far off from accepted industry standards. (See the American Council of Governmental Industrial Hygienists (ACGIH) Manual for standards on minimum air-conveying speeds and system design standards.) This would have exposed that the system was grossly undersized and allowed staff either to correct the problem or to seek a different vendor.

3) Third, seek alternative proposals. Had the company solicited alternative bids, personnel likely would have noticed the obvious discrepancies between them. Additional proposals likely would have shown a large difference in price, owing to the vendor’s undersizing of the system. Other vendors (likely) would have submitted more realistic proposals. Instead of believing that any one supplier somehow may have managed to undercut the competition by such a large margin — while offering an adequate product — the wise course would be to investigate why one bid would come in so much lower than the others and correct any mistakes that may have been made.

Conclusion

Yes, this story is meant to raise concerns over the buying process, but that is a good thing for potential buyers. If they keep in mind the points outlined here, they can avoid the pitfalls of an installing an undersized dust collection system and avoid the complications that can come with it.

Magnehelic gauge for reading differential pressure in a baghouse

Slag processing facility recently agreed to pay over $325,000 in fines for a violation of their air permit. What major infraction lead to such an immense fine? A broken differential pressure gauge on their baghouse! 

By Dominick DalSanto
Dust Collection Expert
Baghouse.com

Portage, Indiana – On September 18th, 2014 a manufacturing plant agreed to pay $325,000 in fines over a broken dust collector differential pressure gauge and falsified reports.

Calumite Company LLC manufactures an additive for the glass industry made from recycled slag from nearby steel mills. As part of its air permit with the state of Indiana, the company is require to operate dust collection systems throughout the plant and to record and report their operation efficiency to state regulators.

Over a period of at least 16 months this particular unit did not have a working differential pressure gauge (also called a magnehelic gauge). Rather than replace the broken gauge, workers regularly estimated DP readings for their reports and then submitted them to state and federal regulators as required. The dust collector in question controlled emissions from the loading and unloading of the company’s product onto railcars and truck trailers. During the course of the investigation, several workers admitted to falsifying reports, and supervisors even admitted to knowing about the broken gauge, but signed-off on the readings and submitted the reports anyway.

Magnehelic gauge for baghouse dust collection system

A broken baghouse differential pressure gauge resulted in massive fines for one facility

What is Differential Pressure on a Baghouse?

State and federal regulators often use differential pressure readings to determine how efficiently a dust collector operates and thus use it as a standard for controlling emissions. Differential pressure is the difference in pressure between the clean and dirty air sides of a dust collector. As dirty air passes through the filters in a dust collector it encounters resistance from the fabric and any buildup dirty on the filters. When the filters are clean there is less resistance and thus a lower drop in pressure between the two compartments inside the dust collector. For this reason, differential pressure readings tell operators the current condition of the filters and the unit in general. If the DP is high, it can signify high dust loading, filter blinding (i.e. clogged filters) which in turn lead to high emissions. A abnormally low reading can also mean that the filters have holes in them or have come lose…also resulting in high emissions.

Lessons Learned? – Do Not Neglect The Dust Collectors

The company was fined for operating one of its dust collectors without taking accurate differential pressure readings. While most dust collection related penalties and fines are related to failure to replace blinded or torn dust collector filters (often due exceeded service life, lower efficiency media, or pushing too much airflow through the filters) this fine comes solely from a failure to accurately monitor the dust collector operation and to record and report it accurately.

The take away here is to never neglect dust collection system maintenance, operation, and especially as this case highlights, reporting. While keeping up with the many regulations, regulations, standards, and requirements imposed on facility managers for dust collection systems might pose a challenge, forgoing the needed maintenance to change something seemingly small and unimportant (in this case a DP gauge) will eventually cost far more in fines, lost productivity, system downtime, and repair costs than maintaining the system properly ever will.

Link to official case record: https://www.justice.gov/opa/pr/indiana-manufacturer-pleads-guilty-clean-air-act-false-statement-violations

 

Baghouse.com now offers free dust collector inspections to new customers in the Los Angeles and San Diego areas.

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

Baghouse.com News | Beginning June 1st, new customers in the Los Angeles and San Diego areas can request free site visits from Baghouse.com. Visits from a dust collector engineer provide far greater value than the usual method whereby companies merely send manufacture’s representative to pitch products.

Upon request, a dust collector engineer will arrange to visit the facility and conduct a condensed version of a standard dust collection system audit. They will visually inspect and review the plant’s dust collectors (if exceptionally large facility , then only primary units), review operating conditions, maintenance procedures, and discuss overall system performance and issues with operators and maintenance personnel. After reviewing the data, the dust collector engineer will present a set of recommendations to improve system efficiency, capacity, and service life of filters, while also reducing maintenance, operating costs (e.g. electricity, compressed air usage, replaceable parts, etc.) and system downtime. If any specific issues are identified during the inspection, or presented by plant personnel, these also will be addressed in the report.

Benefits of a Baghouse.com Dust Collector Report

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 Los Angeles and San Diego areas, 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.

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.