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The Dangers of Sawdust in the Workplace

Lakeland Mills Sawmill Fire
April 2012, Prince George, B.C
Lakeland Mills Sawmill Fire, April 2012, Prince George, B.C
Credit: Jacob Woods/Past Due Studios/MyPGNow

Part 1: A Hazard Hidden in Plain Sight

Wood is a flammable material, a fact everyone learns at an early age.  From campfires to fireplaces to forest fires ravaging communities, we have all seen the delicate fingers of light and felt the heat from a fire at some point.  It’s no stretch of the imagination to conclude that sawdust itself is flammable…but just how dangerous can it be?

To answer that, we need to understand the nature of the sawdust in your workshop.  What type of dust is it?  What kinds of wood and other materials make up the dust?  How large are the dust particles?  How does the dust get moved around, and is it frequently airborne?

The rate of combustion for any material is dependent upon the surface area of the objects or particles being burned.  The greater the surface area means more exposure to atmospheric oxygen, which is required for combustion to occur.  A large block of wood has much lower surface are than an equal mass of sawdust.  The size of the dust particles is very important here: the smaller the particle the more rapidly combustion will consume the entire mass of that particle.  Very fine wood dust (also known as wood flour) has a much more rapid rate of burn than a solid piece of that same wood.

In fact, with the right dispersion in air wood flour can be TEN TIMES more explosive than gasoline!  You wouldn’t want to work in a room filled with gasoline fumes, yet workers are injured or killed every year from combustible sawdust accidents.  The mere act of creating wood flour (e.g. wide belt sanders) results in airborne dust, and dust collection systems are based on the principle of aerial dispersion for the transportation of material.  Quite often the initial explosion causes more dust to become airborne, and a disastrous cycle of explosion and dispersion begins until all potential fuel is consumed by the blaze.  An unprotected dust collection system can quickly turn an explosion into a devastating disaster.

The only thing preventing a catastrophic event is a source of ignition.  A spark can come from a motor when a piece of machinery starts, from a loose fuse connection, or by a loose cutting blade striking a metal surface.  Even a heat source such as a worn bearing in a rotating machine part or a unit heater have been known to cause dust fires and explosions.

A fire requires three things: fuel, oxygen and a source of ignition/heat.  An explosion requires those same three factors plus dispersion of the fuel in a confined space.  These concepts are depicted in the Fire Triangle and Explosion Pentagon diagrams.

Fire Triangle & Explosion Pentagon
Fire Triangle (left) and Explosion Pentagon (right)
Credit: Dr. Chris Cloney, DustSafetyScience.com

For more information on these concepts visit: https://dustsafetyscience.com/combustible-dust-hazard/

Often these disasters mark the end of a business.  The cost of repairing or replacing production equipment & facilities, OSHA fines, and resulting legal actions can be more than the business and its insurance can bear.  From January 2016 to June 2018 there have been 19 injuries and 1 death as a result of wood dust fires or explosions, with tens of millions of dollars in damages and untold millions in lost revenue.  In the first half of 2018 OSHA has issued 29 citations totaling $228,956 in penalties to just 5 companies for incidents regarding sawdust fires or explosions.

For more details on these incidents I highly recommend reading the Combustible Dust Incident Reports from DustSafetyScience.com.  Dr. Chris Cloney, the report’s author, is an industry expert and definitive authority on dust explosions & process safety.



Spark Detection Systems and How They Work

Modern dust collection systems are much more complicated than when they were first introduced nearly 100 years ago. Much of the current dust collection technology has been around for decades, yet recent advances in safety features and digital components have moved the whole industry forward in terms of efficiency, environmental impact, and disaster prevention & mitigation.

It’s that last concept that we will cover in greater detail in this article: disaster prevention & mitigation.

The National Fire Protection Association (NFPA) has provided codes and standards for use by local governments for over 120 years, and more recently has provided detailed standards regarding industrial processes including dust collection and storage. This recent attention to industrial processes is not based solely on good practice, but is inspired by past experience with industrial accidents and disasters. All too often these preventable chains of events result in death or dismemberment of workers at the facilities which suffer from inadequate procedures. Properly installed and maintained explosion prevention systems can save lives, spare devastating damage to facilities, and minimize process downtime in case a potentially hazardous event should occur.

There are a number of NFPA codes which cover the detection and prevention of catastrophic deflagrations: NFPA 69, NFPA 650, NFPA 652, NFPA 654 and NFPA 664. Spark detection (also called optical detection) is an important part of all of these standards. However, these devices are just one part of a larger system of devices and processes, including regular maintenance and good housekeeping.

When an explosive event occurs within a facility which produces combustible dust the risk for fire propagation is extremely high. The shockwave from the initial event can cause more dust in the immediate area to become airborne ahead of the flame front, which travels slower than the pressure wave. This causes more dust to become airborne ahead of the flame front, providing more fuel and a secondary, often larger, explosion. As long as there is fuel for the fire it will spread, and if the space is confined it becomes disastrous and destructive. With proper safety equipment, disaster can be avoided and lives saved. Spark detectors are a crucial component of these safety systems.

 

HOW A SPARK DETECTOR WORKS

A spark detector is a simple device which monitors the infrared light within the field of view of a special sensor which detects light in the infrared range. This light is emitted from all things which emanate heat, and sparks or burning embers emit a greater amount of infrared light in contrast to the surrounding area within a typical room, workshop or factory floor. Fire is also detectable by the spark detector, which means any deflagration event within the ductwork will be registered and abated by a properly designed fire extinguishment system.

Infrared vs. Visible Light (Credit: NASA.gov)

What makes a spark detector different than a standard infrared camera or other sensor is how quickly it operates. For a spark detector to be effective it must sense a rapid change in infrared light coming from a tiny hot particle traveling at high speed through its field of view. Once a spark has been detected, a signal must then be passed to the fire protection system. That system will then process the signal and mark it as an emergency event, which will then initiate fire prevention mechanisms associated with a spark being detected at that location in the dust collection system.

EcoMAXX Spark Detector, by BOSS Products America

All fire prevention devices must be activated before the spark reaches their locations within the collection system in order to be work as intended. To give you an idea of how fast these systems must operate, a particle flow of 4,000 FPM is about 45 mph and 5000 FPM is almost 55 mph. The spark detection & extinguishment cycle must be almost instantaneous in order to prevent disaster, because it only takes one spark to set off an explosion.

 

WHAT SPARK DETECTORS CAN DO

Spark Detectors are the primary sensor in an explosion prevention package used with a dust collection system. They can be tied to activate a single safety component or multiple devices connected to the Fire Control Panel, a programmable logic controller which determines what happens when certain input signals have been received.

There are specific requirements for detector & device placement:

  1. The ducting MUST be straight and uniform throughout the length for even airflow and constant velocity; no elbows, transitions or branches can be positioned along this path.
  2. The spark detectors MUST be installed 1.5 times the diameter of the ductwork downstream from any elbows, transitions, branches or any other fittings which could affect the laminar flow of the air stream.
  3. The device being activated by the spark detectors has its own rules for placement in regards to fittings and distance to the dust collector or other equipment; the placement of these devices determines the upstream placement of the spark detectors along the ductwork.

 

SPARK EXTINGUISHMENT

Spark detectors can be paired with a Spark Extinguishment Set, which are a set of nozzles mounted to the ductwork that pop into the air stream and spray water to quench a flame, similar to automatic fire sprinklers in a building. These are placed at an appropriate distance downstream from the spark detectors so that the spark travels through the water spray and is extinguished before it reaches the dust collector.

EcoMAXX Spark Extinguishment Set, by BOSS Products America

Detectors must be placed at a distance which provides enough time for the detection signal to be sent to the Fire Control Panel, the signal to be processed and sent on to the extinguishment set, and then for the extinguishment set to activate the sprinklers in the duct ahead of the spark. The time it takes to do all of this is less than 250 milliseconds, so we design the detectors to be upstream from the extinguishment set at a distance equal to or greater than 250 milliseconds of travel at the maximum designed velocity in the duct where these safety devices are installed.

Spark Detection – Extinguishment Chart (credit: Boss Products America/GM Sistemi)

 

HIGH SPEED ABORT GATES

When a deflagration has been detected in a dust collection system which returns the output air into the building from which it was drawn there is a risk of that fire entering the building and spreading inside. Obviously, this is extremely dangerous and must be avoided. The fire itself can cause a rapid increase in pressure within the ductwork, and an explosion by definition is an extreme change in pressure.

To reduce the risk of this event spreading within the workspace, a High Speed Abort Gate (HSAG) is used to immediately dump the output air stream into the environment and away from the building. When a spark is detected upstream from the HSAG, a heavy gauge steel diverter flap drops into the airstream and forces all returned air up through a vent atop the gate. Should there be an explosion in the ductwork, this gate will be opened before the pressure wave or flame can be returned to the building.

EcoMAXX High Speed Abort Gate, by BOSS Products America

The High Speed Abort Gate can be wired in with the initial spark detectors inside the facility, or they can be wired to a detection set located on the dust collector outlet ducting downstream from the dust collection fan (see diagram at end of this article). This second arrangement allows for additional safety and control within the system, should the primary set of detection and suppression systems fail to function for whatever reason.

By adding a spark detection system on return air ductwork of sufficient length for detection, the HSAG can then be tripped should a spark or flame make it through the dust collector. The distance between Spark Detectors and the HSAG should be greater than the equivalent of 500 milliseconds of travel at the maximum designed velocity in the duct where these safety devices are installed.

Spark Detection – Abort Chart (credit: Boss Products America/GM Sistemi)

Contact us today for more information on selecting and designing the right fire suppression & safety equipment for your dust collection system. We sell and support Boss Products America’s EcoMAXX line of ATEX-approved safety equipment to help you meet or exceed NFPA standards for fire prevention and safety.

Complete Spark Detection and Extinguishing System (credit: Boss Products America)


  1. Spark Detectors
  2. Test Lamps
  3. Fire Suppression/Spark Extinguishment
  4. Spark Detectors
  5. Test Lamps
  6. Firebreak Shutter
  7. No Return Valve (NRV)
  8. Thermal Probe (in Dust Collector)
  9. Spark Detectors
  10. High Speed Abort Gate (HSAG)


Wet Dust Collectors – What Are They?

Wet Collectors are a common form of dust collection in the machining industry, but can be used in other fields such as food processing, pharmaceuticals and biomedical manufacturing. Wet dust collectors trap dust and particles by passing the air stream through a body of water. The design of the system directs the airflow down towards the water, through impingers or a water spray, and then up through further metal filtration to trap moisture droplets that could be carried by the airstream out of the collector. This system successfully captures airborne contaminants which may pose a risk if not properly contained.

ProVent Uni-Wash Scrub Process

The primary use of these systems is for the capture and collection of hazardous metal grindings & dust. These include metals such as Aluminum, Titanium, Magnesium, Zirconium, Tantalum, Niobium and other such materials which pose a great risk of fire or explosion when in powdered form. For this reason, wet collection is recommended by the National Fire Protection Association for containing dusts made from these metals.

NFPA 484 Section 9 requires that dry dust collectors for such metals be placed outside, and that extra precautions be placed in the form of explosion vents, insulated ductwork, moisture control, grounding of ductwork, prohibition of returning collected air into the building, and other such expensive precautionary measures.

“Industry experience has clearly demonstrated that an eventual explosion can be expected where a bag- or media-type collector is used to collect combustible metal fines. Seldom, if ever, can the source of ignition be positively identified.”
     NFPA 484 Annex A.9.3.1

By selecting a wet-type dust collector you can save money by avoiding all of these measures while also providing added process safety. Dust collectors can be placed inside and much closer to the dust producing machinery, and in most cases the collected, cleaned air is safely returned directly into the work space.

Total Air Energy offers Wet Collectors from two excellent established manufacturers, ProVent and Diversitech.

 

DUCTED WET COLLECTORS

The ProVent offerings range in size, from 500 CFM capacity up to 40,000 CFM. The Uni-Wash UC Series offers a wide range of configurations and have been an industry-leading choice with decades of proven experience. The ProScrub line offers a more economical model based on the same technology as the UC series.

ProVent ProScrub Ducted Wet Collector

Diversitech offers a line of small-to-medium sized wet collectors in the WX-Series. These compact units provide an economical means of meeting NFPA 484 guidelines with optional silencer and HEPA after-filters to minimize the impact of returning collected air into the workspace. Capacities range from 1200 CFM to 6500 CFM and runs on 230V, 460V or 575V power.

Diversitech WX-6500 Wet Collector


 

WET-TYPE DOWNDRAFT TABLES & BENCHES

A considerable amount of metal dust is produced by grinding and finishing operations using powered hand tools, so it makes sense to integrate a wet-type collector into a ventilated work surface. Diversitech and ProVent have created ventilated work surfaces which utilize their wet collection technology and expertise to provide the right solution for your workshop.

Diversitech’s Monsoon line of wet downdraft tables provide a wide selection of sizes and configurations well-suited for work pieces of any size, and come with optional casters for added mobility. The base design is built around an open workspace accessible from three sides, with the fan and outlet stack set to the left side of the work area. Options include enclosures and lighting, water auto-fill control system, auto wash-down system, sludge vacuum kit, and HEPA afterfilter.

Diversitech Monsoon 3X8 Wet Downdraft Table

ProVent has integrated a work surface into the proven Uni-Wash UC Series collectors to create the Uni-Wash DDB Series wet downdraft benches. The wet collector is positioned behind the ventilated work surface, with options including enclosures with flush-mounted lighting and crane slot add-ons, removable dividers, dual-sided configurations, and the Sani-Ball cleaning system. A full NFPA 484 compliance package is also available, including control panel interlock and an auxiliary vent fan for evacuating residual hydrogen gas after the system has been shut down.

ProVent Uni-Wash DDB Wet Downdraft Bench with Enclosure & Crane Slot

 

ENCLOSURES & BOOTHS

ProVent also offers custom-built enclosures and booths for better control of dust on a larger scale. By enclosing the entire work area, dusty air is drawn from one end towards the Uni-Wash UEWC Series wet collectors to prevent harmful or hazardous build-up of explosive metal dusts. Contact us today to determine the best enclosure solution for your dust-producing processes. Unit capacities range from 4,000 CFM to 15,000 CFM, and multiple units can be used to provide an even flow of air across the enclosure or to provide individual work station functionality.

Uni-Wash UEWC Series Dust Collection Booth



Cartridge Dust Collectors – What Are They?

Cartridge dust collectors were developed using an existing filter technology utilized in the automotive and heavy machinery industries: the diesel engine intake filter cartridge. This cylindrical filter design relies upon a pleated filter media design to offer greater filter media area within a smaller space. This design is useful for certain types of dirty air streams, specifically those with low filter loading volumes or with fine dusts. Larger dust particles, abrasive dusts, and stringy/sticky dusts are not recommended for cartridge dust collector designs.

Typical Filter Cartridge

Unfortunately, there are a few big dust collector companies which rely on making filter cartridges a commodity item that you would need to buy on a regular basis.  They are primarily filter manufacturers, and view the Cartridge Dust Collector as another means of selling overpriced filters to a captive market. Although they offer inexpensive dust collectors, these big blue or green boxes frequently need new filters.  This design consideration is a means of securing a dedicated source of income from their customers, who are forced to buy proprietary filters with gimmicky shapes or features that don’t work. This “HP Printer Ink” business model is not fair to you, the customer, as better cleaning systems are available which prolong filter life and reduce your overall cost of ownership.  We offer competitively priced replacement cartridges for those brands when possible, but we will not sell their equipment.

Cleaning of cartridge filters is accomplished by reverse air flow through compressed air, usually in the form of pulse jet cleaning systems. The concept is nearly identical to baghouse pulse jet cleaning systems, with a quick pulse of compressed air momentarily reversing the flow through the filters and shocking the dust off the filter media.

ENCLOSED CARTRIDGE-BASED DUST COLLECTORS

A.C.T. Dust Collectors offers a competitive range of modular Cartridge Dust Collectors, and offers a unique abrasive dust inlet plenum. By adding a collection area to the inlet where the dust enters vertically downward, the build-up of dust provides an area for otherwise-harmful dust particles to collect. At first the particles are collected in this “dead zone” with no means of collection; as the dust builds up to the point it can spill over into the collection hopper it provides an impact buffer which slows the larger dust particles to harmless velocities. This reduces overall operating costs by relying less on the filters for collection, and by avoiding costly abrasion to the filter media.

A.C.T. Cartridge Collectors – (2) 4-48 models

COIMA USA offers a range of indoor/outdoor cartridge dust collectors in their F Series, FC Series and FB Series lineup (the -380 and -450 models use cartridges while the -250 and -320 use sleeve-type filter bags).

PORTABLE & SMALL FORM FACTOR COLLECTORS

Diversitech produces a range of smaller cartridge based collectors as the FRED Jr & FRED Sr series, and now offers a mid-range modular design as the AIRHAWK series. Many of the FRED series collectors are also available as portable models with optional extraction arms. These provide an economical solution for small shops or for work done on large and awkward work pieces where stationary collection systems cannot easily provide sufficient extraction.  ProVent offers the SideKick PSK, a portable collector with one extraction arm (optional) and a tiny footprint.  Movex offers the MF Roll-Around collector for maintenance welding operations, and the ultra-portable handheld SF Collector for difficult to reach spaces.

Diversitech FRED Jr

DOWNDRAFT TABLES

When grinding, sanding, finishing and other processes require a ventilated work surface a cartridge-based downdraft table is the ideal solution for a clean and healthy workplace. Any material removed from a work piece is then captured by the air flowing into the table’s work area and then trapped by the cartridge(s) underneath, or drops out of the airstream into the dust collection trays underneath. Pneumatic cleaning systems (available on most models) clean the cartridges, and the waste material is collected for disposal in removable dust trays at the bottom of the table. Adding optional casters to certain downdraft tables converts them into mobile units, offering flexibility for difficult work pieces or workshops where grinding or finishing is not done withinin a dedicated section of the workshop.  We offer ProVent Intercept PDB benches, Diversitech DD Series tables & workstations, and COIMA USA BAP Series tables.

Diversitech DD-3X8

In some cases it may make more sense to utilize Ducted Downdraft Tables and a central dust collector system.  These tables have a grated & ventilated work surface but no integral dust collection.  The duct outlet is placed on the side, rear, or underneath the table, and ductwork connecting the table to the collector provides the extraction for the work surface.

LASER PACKS

Over the past several years we have seen a growing trend in dedicated cartridge dust collectors for designed for Laser Cutting and Plasma Cutting systems. We offer competitive solutions from Diversitech, A.C.T. and Movex for these applications. These systems are located near the CNC cutting system with sufficient ducting that the vapors have time to cool and condense into a dust which can be collected through cartridge filters. We strongly recommend the addition of a spark trap device to the ductwork.  This prevents hot embers from entering the collector (a serious fire hazard), and the added turbulence has a bonus effect of increasing the rate of vapor precipitation as dust. A properly configured Laser Pack can make a drastic difference in visibility and air quality during the cutting process, and reduction in dust accumulation in the vicinity. Contact us for more information if you are looking for a dedicated solution for your CNC cutting equipment.

A.C.T. LaserPack 4

ENVIRONMENTAL CONTROL BOOTHS & MODULES

Often dusty air is a difficult and pervasive problem in some work environments, such as grinding or finishing of large items or surface areas, and a dedicated environmental solution is required. Environmental Control Booths & Modules offer a means of filtering large quantities of air at a given point, allowing for a regular cleaning of the air within a confined space. The modules can be placed along one wall of a room, opposite to the opening, to collect dust from the air as it flows from the open side towards the collectors. This directed flow of air allows for a regular cleaning process to occur and maintains an environmentally clean and safe workspace.

ProVent Enviro-Cell

If a dedicated room is not available, an enclosure is provided as an option to ensure that all of the dust produced during the grinding or finishing processes is contained and collected in the most efficient way.  These include a number of options, including fully-enclosed areas with doors and return air curtain at the front of the enclosure to promote desired airflow through the work space.

ACTion Booth

WELDING SMOKE CONTROL

A similar means of cleaning air in larger work areas where welding occurs can be accomplished by ducting the inlet and outlet of a cartridge collector to direct airflow across the work area. The ducts at each end feed to/draw from a series of diffusers and grilles, providing a controlled cross-flow of air. Welding smoke has a tendency to stratify at a certain height within a workspace; by locating the diffusers and grilles at that elevation above the floor the welding smoke is effectively removed from the work space, providing a cleaner and healthier workplace for your employees.

We recommend Diversitech AIRHAWK and A.C.T. Cartridge dust collectors for welding smoke control solutions, including as a central collector for a network of welding arms.

Environmental booths and welding smoke collection systems are rated by the number of air exchanges per hour in a given space. That is the amount of air which can be moved through the workspace and cleaned by the collection systems in one hour of operation. For example, a work area that is 20’ wide x 30’ long x 20’ high has a volume of 12,000 cubic feet. A collection system with a nominal capacity of 2,000 CFM will clean 12,000 cubic feet in 6 minutes. This solution provides 10 air exchanges per hour, which is adequate for light to moderate welding.

Diversitech AIRHAWK



Baghouse Dust Collectors – What Are They?

By the name alone, it’s easy to guess what a Dust Collector is designed to do. However, there’s more to just sucking up waste materials when it comes to these essential machines. The most important aspect of dust collector design is what kind of material is being collected. Wood chips will require a different kind of filtration than metal shavings, just as sand has different requirements than lead oxide or salt. Every material has specific properties which affect the velocity at which they must be collected, and the filtration method by which they are pulled from the air stream.

Let’s start with a list of basic dust collector types:

  • Baghouse Dust Collectors
  • Cartridge Dust Collectors
  • Wet Collectors/Air Scrubbers
  • Mist Collectors
  • Cyclones & Inertial Separators
  • Electrostatic Precipitators

These six concepts cover all of the variations of collectors and collection devices available in the market today. This series of articles will explain the first five of these in detail, and describe the various types of each collector. Total Air Energy provides a wide selection of each of these systems, and you will find links to these options throughout the text.

Baghouse Dust Collectors

The first dust collectors relied upon bag filters which trapped dust and particles blown through a fan and into the bag. An early advancement in this design was the use of a frame to support a series of envelope bag filters which worked in parallel to trap particulate matter as it was drawn through the filters by a fan placed on the clean side of the collector housing.

Assortment of Bag Filters

Assortment of Bag Filters

POSITIVE PRESSURE VS. NEGATIVE PRESSURE

The main difference between these two concepts is the location of the fan; positive pressure arrangements blow air through the filters (located upstream), whereas negative pressure arrangements draw the air through the filters from the other side (located downstream). Negative pressure designs require an enclosure from which to create a negative pressure space (vacuum) to draw the air through the collection system.  This enclosure provides greater control of the process, and allows for a number of advanced features for safety and functionality.

One of the primary advantages of negative pressure systems is the efficiency of a clean air fan design versus a dust-laden air/material handling fan. Typically, a negative pressure fan (backward inclined or backward curved) is 30% more efficient than fans designed for the rough environment and looser tolerances of conveying dirty air.

ENCLOSURELESS BAGHOUSE COLLECTORS

If you have been in a small woodshop with a dust collector, you have probably seen a common type of bag collector: the enclosureless baghouse. These are very affordable, but can often be ineffective as dust collectors. The filters need frequent cleaning, which requires the collector be shut off and the bags beaten with a stick or shaken by hand.  The bags themselves can also be poor filters, which defeats the purpose of having a dust collector in the first place.  More advanced enclosureless systems offer a vibrating ‘shaker’ mechanism which cleans the filter bags whenever the system is shut off.  Online cleaning is not possible with this type of collector.

To minimize on space, the most common models have an extremely high air-to-cloth ratio. This means that a lot of air must pass through a small amount of filter media in the bag. This often results in fine dust being forced through the filter bag and a tendency for the filter media to load up quickly. This can be dangerous, as fine wood dust is prone to explode under certain conditions.  In fact, aerosolized wood flour (very fine wood dust) is TEN TIMES more explosive than gasoline vapors!!

When choosing an enclosureless baghouse collector, it is important to understand the risks of poor filtration and select a model with lower air-to-cloth ratio and the correct filter media for the job. More, smaller filters are better than fewer large filters. Contact us to determine the best collector for your workshop.

COIMA USA SHK Series

Enclosureless Dust Collector

NFPA guidelines require Enclosureless Dust Collectors to be located 20’ from any area routinely occupied by personnel or used as a means of egress, and the equipment cannot exceed 5,000 CFM airflow capacity.
      NFPA Standard 664 8.2.2.6.1.6

ENCLOSED BAGHOUSE COLLECTORS

An Enclosed Baghouse Dust Collector is the most common and most versatile type of dust collector available on the market. From a small collector designed for a few of machines in a woodshop to massive collectors at major industrial sites processing millions of cubic feet per minute of dust-laden air, the enclosed baghouse offers the most coverage for dust collection needs worldwide.

COIMA USA UPD Series

UPD Series

UPD Series Pneumatically-Cleaned Large Baghouse Dust Collector

These collectors function as part of a negative pressure system, with the fan typically mounted on the ground adjacent to the collector with ducting running from the clean air outlet to the fan inlet. Smaller collectors sometimes employ a fan mounted directly to the top of the clean air plenum (the large box atop the collector surrounding the clean air side of the filters). Filter types include envelope bag, fabric bag, and pleated bag designs.  Outlet airflow can be exhausted to the environment, or returned to the building through ductwork.

Certain processes may require special fire suppression and explosion protection equipment.  Total Air Energy recommends EcoMAXX safety products in all installations requiring these devices.  Contact us today to learn more about preventing disaster in your workplace.

The most common and versatile of these is the fabric bag, which is a sleeve of filter fabric surrounding a steel wire cage. This “socks in a box” design offers the widest range of sizes, filter media types, and features a pneumatic cleaning system which provides continuous operation of the dust collection system while cleaning. The steel cage provides a support from inside the filter sleeve while dust builds up on the outside, forming a dust cake.  The filter media material varies depending on the process characteristics.  These include type of dust, size of dust particles, temperature of air & dust, and oil content or humidity of the airstream.  With a variety of materials and treatments, we can provide filters which can withstand a number of conditions including oil or water content and temperatures up to 500° F (260° C).

When the filter media is cleaned, a high-pressure pulse of compressed air is shot down the center of the sleeve from the clean air side. This rapid change in pressure and reverse flow inflates the filter sleeve to pulse off the dust cake. The change in airflow and the change in the shape of the filter media helps provide an effective method of filter cleaning that cannot be reproduced with other filter types.




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Call 206.454.7070 today for help with your next dust, fume, mist or vehicle exhaust project!