Frequently Asked Questions
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Baghouse Design & Operation
Industrial baghouse dust collection systems collect and filter the harmful dust and airborne materials generated by industrial process before releasing the air back into the environment while keeping the gathered waste together for easy and safe disposal.
A well-designed system, with the right collector size and style, operates efficiently, maintains low operating costs, and captures all target dust without compromising safety or emitting pollutants. However, poorly functioning systems may fail to capture all dust generated by a process, leading to compromised product quality, frequent filter blinding, high maintenance costs, safety hazards, and/or emissions that risk exceeding air permit limits. At Baghouse.com, we help you choose the right system, ensuring not just functionality, but the best performance.
Many so-called “dust collection experts” are really just sales rep organizations that have little technical background or engineering experience with these systems. As such, they will often sell whatever product lines they have with little regard for making sure it is the best fit for your specific application. Others vendors purposefully recommend undersized systems in order to undercut other vendors on pricing, regardless of how the end system performs for the customer.
For this reason, Baghouse.com has prepared a detailed guide for system sizing, which we offer free of charge. Click here to download the complete eBook: How To Size a Baghouse Dust Collection System.
A cyclone dust collector is a mechanical device that is used to remove particulate matter from air or gas streams. It works on the principle of centrifugal force, which is generated by a rapidly rotating cylindrical chamber.
Unlike a standard dust collector or baghouse that uses filters to collect dust from the air, allowing clean air to pass through, a cyclone dust collector uses centrifugal force and the momentum of the dust-laden air to pull out heavier dust from the air stream. They are particularly effective for removing larger or non-uniform particles that might clog a cartridge or baghouse collector.
Explore the different features of cyclone dust collectors here.
At its core, an ambient air collection system is a type of dust and fume collection system. It operates by efficiently filtering airborne particles from the atmosphere. Cartridge collectors are commonly recommended for ambient systems due to their efficiency and compact design.
The best method of hopper discharge varies from application to application and from unit to unit. However, this does not mean that all discharge methods work for all baghouses. Serious problems arise when the baghouse hopper discharge system is not adequate to the dust loads passing through the unit. Additionally, the disposal methods may require more manpower than available at the plant and lead to spillage and other issues.
Read more to identify which discharge system is the right for your application.
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 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.
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.
Read more about differential pressure and why you need to monitor it.
In most applications a baghouse dust collector should run between 3″ to 6″ w.g. under normal use. Once levels rise above 6″ (roughly) and the cleaning system cannot return it any lower (even when turned to continuous cleaning or “Test” mode) it is a sign that the filters are beginning to be blinded and likely need to be changed. It is not advisable to run a baghouse with a DP higher than 6″ for any length of time as this will have an impact on the function of the entire system. Running at such a high DP will lead to a number of problems including vacuum loss at the pickup points of the system (loss of suction), lower air speeds in the ductwork, higher emissions, and higher energy usage.
If you are seeing levels below 3″ after having run the baghouse for some time you liking are getting false DP readings. When brand new bags are installed in a dust collector they should provide approximately 1″ of resistance alone. Once they begin to load dust that number will rise to between 2″ – 3″ no matter how much you clean them.
A clean on demand baghouse controller (i.e. clean on pressure) is the best way to keep a dust collector running in the recommended DP range.
See article: 3 Cheap Ways to Increase Efficiency in Dust Collection Systems
The conveying velocity is the minimum airspeed required to keep dust particles suspended in the dust collection system. When the air in any part of the dust collection system slows below the minimum conveying velocity the dust will begin to drop out of the airstream and settle to the bottom of the ductwork (known as product drop out).
Preventing product drop out is even more serious in applications involving combustible dust. Any accumulations of dust within the ductwork provide a potential fuel source for any ignition source that may find its way into the ductwork such as sparks. Additionally, if the system is operating below capacity due to blockages, dust may accumulate elsewhere in the facility including on elevates spaces that can then become fuel for both primary and secondary dust fires and explosions.
Often times, manufacturers and sales rep organizations deliberately sell their units cheaper and then make convince their customers that they are locked into using a proprietary filter design that only they can supply and thus they charge outrageously high prices for them.
While many other firms simply sell whatever is convenient for them, Baghouse.com always looks for ways to improve your operation, cut your operating costs, or increase your filter life by offering suggestions for different fabric/finish combinations or conversions to new bag/cage styles or even to pleated filters when speaking with you.
Blinded filters mean the filters are so loaded with dust that they can no longer be cleaned by the baghouse cleaning system and must be replaced.
During normal operation dust particles accumulate on the surface of the filters and form a dust cake, which is then cleaned by the pulses of compressed air during the cleaning cycle. Overtime, some dust particles pass through the surface layer and become embedded deep within the fibers of the filter fabric where it cannot be removed by the cleaning pulses. Eventually, the fabric becomes so filled with dust particles that it severely restricts the movement of air through the filter. When this occurs, the filter is said to be “blinded”.
The On-Time setting on your control board determines how long the pulse valve is open for during a cleaning cycle. This setting is VERY important for proper cleaning of the baghouse filters on a pulse jet dust collector. If set too long then the air pulses will be weak and waste compressed air, lower pressure in the air header (causing delays while it builds back up or weakening the following pulses) or even damage the filters. If set too short, not enough air volume will be released to clean the entire bag. It will also cause uneven dust loading on the bags, which in turn can cause a long list of problems in the collector.
As a general rule, this should be set to between .01 – .015 ms (milliseconds). For certain specific applications (such as pleated filters, or certain “sticky” dusts) your dust collector OEM might provide you with a slightly different setting.
Clean on demand (or clean on pressure) is a means of controlling a pulse jet baghouse cleaning system. It is the most effective way to operate your dust collector and it can lead to considerable savings in several areas.
Using a clean on demand baghouse controller, operators set high and low differential pressure points (usually 5.5″ and 3″ respectively). When the DP reading hits the high point the control board begins firing the pulse valve(s). It will continue firing them in order until the DP drops below the low point.
In contrast to a simple timer board, a clean on demand controller only cleans the bags only when necessary to maintain stable operation. This prevents over cleaning (which increases wear and produces higher emissions), reduces compressed air use (costly in most plants), and reduces wear on the diaphragm valves. Additionally, clean on demand controllers are able to adapt to changes in dust loads (common in most applications) something timers cannot do.
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.
Expand your knowledge on the difference between the two here.
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.). These problems drastically increase if the collected dust contains hazardous materials (lead, mercury, etc.), are an explosion hazard (food products, metal powders, fertilizer, etc.) or are corrosive to machinery.
Read more about the dangers of collecting dust in your hopper here.
It’s not uncommon for companies to try to convince their clients that a one-size-fits-all approach is best when it comes to dust collectors, either because it’s the only style they manufacture or because they aim to provide the lowest bid. However, at Baghouse.com we offer multiple kinds of dust collectors and we prioritize recommending what works best for your application rather than trying to be the lowest bid without regard for how it works. We ensure that you not only get a dust collector but the right one that aligns perfectly with your operations.
Recommended article: 5 Key Factors When Budgeting for Your Dust Collection System
Baghouse Maintenance
Industrial applications utilize three different air filtration and dust collection systems: filter bag collectors, cartridge collectors, and cyclone collectors.
Filter bag collectors use filter bags to capture and separate harmful particulates, dust, and other contaminants. Cartridge collectors are used for very fine dust and other special or uniquely shaped contaminates. A cyclone dust collector uses centrifugal force and the momentum of the dust-laden air to pull out heavier dust from the air stream.
Take the following things into consideration prior to selecting your filter:
Step 1 – Filter Media Selection
- 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
Step 2 – Dust Collector Filter Measurements
- Flat Width
- Diameter
- Length
Step 3 – Select Top & Bottom Construction
For additional information about the different filter options, click here.
To order filters, click here.
The main signs to know if your filters are in good condition or if they need to be replaced are whether they can be cleaned effectively or not by the baghouse, or if they start leaking.
Baghouse filters have an average service life of 1-3 years in most applications. Some can go beyond that without major increases in emissions, while others may last less than a year in more difficult applications. The two main reasons to replace baghouse filters at the end of their life are (1) because blinded filters will begin to have higher and higher emissions (even if there are no holes) and (2) old filters have higher differential pressure (i.e. pressure drop), which decreases the airflow through the system, causing cascading effects of reduced dust collection at pickup point (fugitive dust emissions) and dust buildup in the ductwork.
The answer is no. They are simply not designed to be washed. In fact, we highly recommend against washing filters for the following reasons:
- Since most bag filters are made of felted material, washing them with water destroys the integrity of the filter – kind of like putting a felt hat in the washing machine. While these washed filters might get you by for a short time, the filtration efficiency and integrity of the bag is ruined. Your filters are much more likely to leak and will certainly not last as long as a new filter.
- While washing bag filters often make them look cleaner, once a filter is ‘blinded’ with dust ingrained in the fabric it cannot be brought back to a like-new condition. Your filters will operate like a blinded filter – higher differential pressure, more energy required to maintain draw, and most likely dust leakage through the filter.
So in short, we highly recommend you consider the total cost, efficiency and performance tradeoff of new filters vs. ‘washed’ ones before you go down that path.
Read more about filter service life here.
To order filters, click here.
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.
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.
Receiving a free Baghouse.com quote for dust collection bags, dust collector accessories, or dust collector services is easy. For a quote on dust collector bags we will need you to provide us with some information about your bags.
1 – What kind of bags, such as cartridges, bags, or pleated.
2 – Dimensions you need, flat width, diameter, length.
3 – What material do you need, (e.g. polyester, PTFE, etc…) any finish (or treatment) and any special construction such as support rings, top and bottom construction, etc.
4 – How many you need
5 – When they need to be delivered by
If you are not sure about the details, you can always mail us a sample bag from your plant or email us a few pictures of them. Once we receive it we can figure out all the specs we need to give you a quote.
To request a quote for filters, click here.
HEPA after-filter stand for High Efficiency Particulate Air. The HEPA after-filter acts as a secondary filtration stage, capturing even the tiniest microscopic particles before the air is returned to the facility.
For more info read What is a HEPA After-Filter and When Do I Need One?
Consider incorporating a HEPA after-filter in the following scenarios:
- — If your process generates fine particles that pose health risks or can contaminate products.
- — When regulatory or industry standards demand exceptionally high air quality.
- — If the collected dust contains hazardous materials, allergens, or carcinogens.
- — When you aim to recirculate filtered air back into the facility, necessitating cleaner air to improve indoor air quality.
For more info read What is a HEPA After-Filter and When Do I Need One?
- Flat Width: Lay the bag out on a table or floor, flatten it completely. Use a tape measure or ruler and measure the width across the bag.
- Length: Measure along the seam running the length of the bag. Start at the center of the snap band and end at the first stitch at the bottom of the bag.
- Tubesheet Hole Size/Snap Band Size: Measure with calipers across the center of the hole in a straight line from one edge to the opposite edge. Also measure the thickness of the tubesheet.
For more details about measurements, read How to Measure Your Baghouse Filters & Cages
- Length of the cage: Measure from top to bottom.
- Diameter: Measure diameter in the middle of the cage at the widest point between wires. Ideally, using a Pi Tape to determine circumference will yield a preferred measurement.
- Bottom construction: Determine if the bottom cup is crimped or if the wires are welded to the cup.
- Number of rings: Count the number of rings.
- Space between rings: Measure the space between the rings. Note: the space between the last ring and the bottom of the cup may be different.
- Number of vertical wires: Count the number of vertical wires running the length of the cage.
- Material: Plain steel, galvanized, coated, 304 stainless steel, or specify if it is some other material.
- Determine the top construction of the cage.
For more details about measurements, read How to Measure Your Baghouse Filters & Cages
Neglecting regular dust collector maintenance can result in sluggish system performance, leading to costly repairs for both the dust collector and equipment affected by dust buildup. Repairs cause system downtime and production loss. Furthermore, an improperly functioning system can pose health risks to everyone in the vicinity, including workers, managers, owners, and visitors.
Regular inspections should be scheduled at various intervals, including daily, weekly, monthly, quarterly, semi-annually, or annually. By adhering to a maintenance checklist, your dust collection system will continue to operate efficiently for years.
Whether you need parts, filters or a system inspection to improve the efficiency of your dust collectors, the experts at Baghouse.com can simplify the maintenance process by providing you with the knowledge and supplies needed that will save you lots of downtime, money, as well as headaches!
Of course you can! But you want to make sure they are properly qualified for the task. With dust collection training from Baghouse.com, your maintenance technicians, maintenance planners, engineers, operators and reliability staff will be able to keep your systems running at maximum efficiency, troubleshoot any problems that may arise, and optimize the systems to meet the demands of production.
The answer is yes! However, you have to be careful who you outsource this vital task to. Inexperienced contractors often get in over their heads after accepting a contract to replace filters, only later discovering the complexity of the task. A rushed or improper installation can cause problems later due to early filter failure in some cases costing millions of dollars to replace. By choosing Baghouse.com filter replacement service, you can be confident that this vital maintenance to your dust collector will be performed correctly. No surprises or unnecessary change orders will be needed due to poor planning.
Why Do My Baghouse Filters Fail?
The regular operational life of a baghouse filter can be shortened by a number of factors.
- Abrasion
- Exceeding Maximum Operating Temperature
- Chemical Attack
- Fire
- Undersized Dust Collector for CFM
- Wrong Filter Media or Style of Filter
- Bent and Damaged Cages
- Poor Installation
- Moisture
Most leaking baghouse filters begin as small holes or rips that overtime become worse and worse. Catching a leak quickly is crucial. Triboelectric systems are sensitive enough to detect even the smallest of increases in dust emissions such as when a bag first begins 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.
Having accurate differential pressure readings is essential to operating your baghouse correctly, and efficiently. Operators base almost all of their operational decisions on baghouse differential pressure. If they are given incorrect readings it could result in damage to the system, increase emissions, or even fire and combustible dust hazards.
Read more about the troubleshooting procedure.
Some of the most common problems are insufficient airflow rate coming from the blower, or ductwork system, excessive airflow rate, high static pressure and a low airflow rate or material is bridging in the hopper.
Read more about the fan and ductwork troubleshooting procedure.
Baghouse Accessories
Rotary valves or Airlocks are mechanical devices that facilitate the transition of materials from pressurized environments, such as dust collectors, to unpressurized points, like storage bins or drums. They come in various types, sizes, and materials to suit different industrial applications.
Find out here which airlock is the right one for your application.
Quality filter cages are built to withstand cleaning cycles, bag changes, abrasive materials, high temperatures and many other environmental conditions they might encounter.
The venturi, or diffuser, accelerates compressed air at the center of the cage, optimizing the cleaning of bag filters. Venturis are made in a variety of materials including aluminum, carbon steel, galvanized and stainless steel.
- Differential pressure gauge: As dust accumulates on the filters, the pressure drop across them increases. The differential pressure gauge measures this pressure drop and provides a reading that indicates when the filters need to be cleaned or replaced. This helps to maintain the efficiency of the dust collector and prevent damage to the system.
- Static pressure gauge: By monitoring the static pressure at different points, operators can identify areas of the system that may be causing airflow restrictions or problems with the system. This can help to diagnose issues with the system and optimize its performance.
- Flow sensor: The sensor typically consists of a probe that is inserted into the ductwork, and it measures the velocity of the air passing through the duct. By combining this measurement with the cross-sectional area of the duct, the flow sensor can provide an accurate measurement of the airflow rate. This information is useful for optimizing the performance of the system and maintaining a safe working environment for operators.
The process is the same for magnahelic and photohelic gauges, as well as timer boards and control boards with on-board pressure sensors.
- Determine what kind of differential pressure controls you will use
- Decide on the location of your control(s)
- Decide on the location of your air taps and plan your air line runs
For a detailed guide to ensure proper installation, click here.
Industrial Health and Safety Regulations
Any industry that produces materials of a fine particle size that are combustible, and many that simply though their day-to-day operation create large amounts of secondary dust are at risk for dust explosions. Industries such as Metal, Food, Plastic, and Wood Processing are just a few that are at risk for this kind of industrial accident. Implementing a comprehensive dust control program, including hazard analysis, implementation of proven dust control and ignition control techniques, damage mitigation, and employee and management training will save lives, time and money.
The Occupational Safety and Health Administration (OSHA), the Mine Safety and Health Administration (MSHA) and other government organizations set standards and guidelines to safeguard employees and minimize the risks associated with airborne particulates.
By conducting thorough dust hazard assessments, implementing effective housekeeping practices, controlling ignition sources, and employing engineering controls, employers can significantly reduce the risk of dust-related incidents as well as fines and violations, and ensure the safety of their workers and facilities.
Additionally, training should be conducted regularly for your maintenance, operations, engineering, EH&S, and management staff that are involved with dust collection.
For all equipment used in explosive atmospheres, regular inspections are mandatory to pass an audit. The specific intervals and requirements vary based on the manufacturer and notified bodies responsible for type approval. Compliance checks must include the following:
- Explosion Isolation System Inspection Requirements
- Inspection Points
- Documenting the Inspection
Additionally, regular training for key personnel is crucial. This includes not only personnel directly involved with the equipment but also those responsible for emergency procedures, such as Building Management System (BMS) operators. Having an accessible emergency checklist is vital for quick, effective responses during alarms, ensuring everyone knows what to do in critical situations.
Read more about our Training for Maintenance and Safety Personnel.
Some of the potential hazards in welding are harmful dust, heat, smoke, fumes, and light radiation that is injurious. The smoke produced by welding can be toxic in itself since they are gasses.
Some of the regulatory precautions are:
- A responsible individual must inspect the area and identify precautions to be taken preferably on a written Hot Works permit
- Fire extinguishers must be ready for immediate use
- A fire watch lasting at least 30 minutes after the welding or cutting operations is required if more than a minor fire might develop
- All combustibles must be moved 35 feet away or properly protected or shielded
Grain dust collection is a paramount concern within the grain and seed industry, given the frequent occurrence of grain dust fires and explosions. Grain processing facilities encompass a multitude of machines and processes, all of which require meticulous dust control to comply with OSHA and NFPA standards. Failures in grain dust control not only compromise workplace safety but tragically result in injuries and fatalities.
Inspections & Training
In general, we enter the plant on day one and conduct a full inspection/audit of your plants systems. Then we conduct the training class and tailor it to your specific needs based on our findings from the inspections (includes information provided in form of drawings, specs, etc. and info gathered from speaking with plant personnel).
The course program is useful for maintenance, operations, plant management, EH&S, and engineering staff. There is no limit to how many personnel can attend the class.
Of course! We have highly trained instructors that can provide the training and materials both in English and Spanish.
Our experts can visit your facilities and perform a thorough inspection of all your baghouses. They will provide you with a comprehensive report of the things that could improve. Additionally, with a highly trained field service team, and decades of experience, you can trust Baghouse.com to do the filter service with minimal downtime.