Dust Collection for Hazardous Rubber Grinding

Common rubber grinding dust generating processes include tire manufacturing, retreading and recycling as well as the production and recycling of appliance moldings, rubber gloves and various automotive parts. Rubber dusts in these types of applications pose challenges for industrial dust collection systems as well as potential health hazards for workers.

Oils in rubber are the biggest problem for dust collectors. In horizontal cartridge collectors, the filters get saturated and the pleats fail. Heat is also an issue as hot pieces of materials can lay into the horizontal cartridges and burn the filter media. Rubber grinding dust has an explosive nature since rubber products in these applications are largely made up of petroleum based products. Explosion vents on the dust collector should be considered as a minimum requirement.

Rubber grinding dust poses serious health hazards to workers. Rubber compounds are full of fumed silica, plasticizers and elastomers that give off unhealthy fumes. Oily smoke has hydrocarbons that can be inhaled or absorbed through the skin. Read more about Dust Collectors for Rubber Grinding.

Case Study: Nuisance Limestone Dust Cleaned Up for Employees

Got quarry dust? Then read on. Indiana Limestone Co., Inc. (ILCI) of Bedford, IN, needed to find a way to clean up massive amounts of dust generated in its limestone cutter's bay. Though limestone dust is completely non-toxic - being classified by OSHA as a nuisance dust - the word "nuisance" describes it well. The fine powdery material hinders visibility in the work area, permeates sensitive tools and machinery, and creates continual cleaning headaches. To solve the problem, the company invested in a high efficiency cartridge dust collection system.

"We wanted to solve these problems and create a more comfortable and pleasant environment for the 17 to 25 employees who typically work in this area," said ILCI General Manager George James. Continue reading this limestone dust collection case study...

FAQ: How often will I need to change my cartridges?

The frequency of filter cartridge replacement in industrial dust collectors is affected by many factors and is different for every application. So, this frequently asked question is a tough one to answer. A properly sized collector with careful consideration to the type of dust and the appropriate air volume per cartridge for the application is crucial to long filter life.

If a dust collector is poorly designed, the dust hitting the filter will abrade it in a short amount of time, ultimately resulting in a leak. This happens frequently with horizontal cartridge designs. Vertical cartridge designs prevent the uneven build-up of dust on a cartridge, which blocks usable filter surface area and increases the likihood of the filters plugging sooner. Continuous pulse cleaning of the cartridges also contributes to wear, typically causing a rip at the edge of a pleat on some inferior quality filters. Smart 'on demand' cleaning systems that only pulse the cartridges when they reach a predetermined 'dirty' point (measured by pressure drop) greatly extend the cartridge life.

All filter cartridges will eventually plug up beyond a usable point, again, for a given application. Operating conditions, dust loading, the physical properties of the dust particles and the velocity at which they hit the filter media all play a role in the life expectancy of a filter cartridge. The bottom line is that your dust collector supplier should be able to give a good estimate of cartridge life, whether it be months or years. Ask for a documented performance guarantee. If the dust collector supplier won't give you one, take your business elsewhere.

Explosion Protection and Dust Collectors for the Paper Scrap Industry

Companies that handle paper and scrap are among the businesses heavily impacted by the explosion venting requirements outlined in NFPA 68 Standard on Explosion Protection by Deflagration Venting. In the process of making paper or paper products, dusts are generated during cutting, slitting, scoring, shredding and other processes - and these dusts are potentially combustible.

The PDF article, An explosive situation: New explosion venting requirements have a major impact on the paper industry, provides a discussion of NFPA 68, how it applies to the paper industry, and identifies specific actions that you must take to ensure compliance. If your business is a printing facility, uses industrial paper shredders, generates corrugated box scraps or has a similar application, read this informative article. Taken from Dust Collectors for Paper Scrap Systems.

FAQ: How do these things work?

This is an honest and candid question we often get, referring to our industrial cartridge dust collectors. Click this image thumbnail to view the full-size illustration. It shows and explains the basic operation.

Related to this, there is an earlier post on this blog regarding the Anatomy of a Dust Collector. Additionally, Wikipedia has a page on dust collectors that includes illustrations on how other types of dust collectors work.

Download: Unit Conversion/Calculation Utility

We distribute a unit conversion utility program to our dust collector sales engineers. Someone suggested that I post this handy program on this blog, so here you go. When sizing dust collection equipment in metric, we often convert values in cubic feet per minute (CFM) to cubic meters per minute. But that's a mere fraction of what this non-invasive little conversion program can do. (Click the thumbnail image to see a full size screen shot.)

Just enter the value you wish converted into the 'From' edit box. Pick the tab (Temperature, Distance, Mass, Area, Volume, Pressure, Velocity, Acceleration, Force, Energy, Power, Fuel Consumption, Flow or Torque) relating to the type of conversion you wish to do. Then pick the units for the 'From' value and the 'To' value. It's easy and many find it convenient, saving it to their desktops for quick access.

To download, click the following link and choose to SAVE the single file to your computer. Then use it! It's self-contained and does not need to be 'installed.' Download and SAVE file now.

In The News: OSHA Inspections/Citations for Combustible Dust Hazards

OSHA compliance officers have identified 3,662 violations where employees may be exposed to potential combustible dust hazards on the job. This report comes after the agency conducted 813 inspections at companies during the last 16 months. These visits are part of OSHA's ongoing National Emphasis Program (NEP) that it says is designed to reduce workers' exposure to combustible dust hazards.

OSHA also sent out a letter to over 30,000 facilities last year to bring attention to this issue. Did you receive one? If so, they have identified your company as being in an industry that faces this deadly hazard. If not, make sure you are not putting yourself, your business and your employees at risk anyway. OSHA wants to help and offers a free, confidential on-site consultation through a program designed for small companies (250 or less employees). There are some helpful insights and links regarding combustible dust (ComDust) Enforcement/Inspections here.

UPDATE (6/22/09 1:10pm):
Case in point: Serious citations issued to whey processing plant in Wisconsin. View the OSHA Inspection Detail.

Case Study: Seed Company Turns to Cartridge Dust Collectors for Efficiency, Safety

Each year, farmers plant and grow soybeans, summer wheat, or winter wheat. After the harvest, they transport the seeds to production facilities, where the seeds are conditioned for later use. The seeds are cleaned, then coated with herbicides and insecticides before being packaged and distributed to various outlets for sale. This conditioning process generates a significant amount of dust with multiple challenges for collecting it as well as minimizing the hazard potential.

Pioneer Hi-Bred, a DuPont company develops, produces, and markets a full line of top-quality seeds, forage, and grain additives, providing services to customers in nearly 70 countries. They faced these challenges, unsatisfied with their existing cyclone dust collectors. If you are a seed processor, read this case study on how filter media cartridge collectors provided the high efficiency that Pioneer Hi-Bred needed to meet EPA dust emission standards and improve the working and safety conditions inside the facility. Full case study here...

Dust Collectors for Mining

Controlling dust from mining equipment at excavation sites, mill transfer points and similar locations is a difficult challenge. The EPA has strict limits on annual emission amounts. If emissions are too high, production schedules may be curtailed. That's why proper selection of dust collection equipment (including pleated baghouses) is such an important concern. Minimizing emissions allows production of more product.

Rock crushing, coal mining dust processing, and bin venting of quarry storage are mining applications. Some are really tough on dust collection equipment and call for custom components. Stack test results of less than .0005 grains per cubic foot of emissions can be achieved with the right configuration and filter media. One of the main concerns with pleated filter media is how well they hold up against moisture. Read more at Dust Collectors for Mining...

In The News: Imperial Sugar Reopens GA Refinery

Factory dust explosions are real. On February 7, 2008, a massive explosion killed 14 workers and injured dozens more at Imperial Sugar's Georgia refinery plant when accumulated sugar dust ignited like gun powder. Sixteen months later, Imperial has rebuilt their plant and just reopened.

Dust explosions and fires in factories occur frequently, though you don't often hear about them. (try this: Google "factory dust explosion"). The more catastrophic ones like at Imperial make national headlines. Don't minimize or dismiss this risk factor. If you are considering the purchase of an industrial dust collector from any manufacturer, please have your dust tested and your application carefully reviewed. Don't rush just to get any dust collection system installed to get OSHA off your back. You likely already have some idea if you have combustible dust. Do some homework. Please prevent another tragedy.

FAQ: Who is the NFPA?

The NFPA (in regard to industrial dust collectors) is the National Fire Protection Association, a U.S. organization that creates and maintains minimum standards and requirements for fire prevention and suppression activities, training, and equipment, as well as other life-safety codes and standards.

NFPA 68 is one of the standards that affects you if you're in the market for a dust collection system. It is the Standard on Explosion and Protection by Deflagration Venting. It applies to the design, location, installation, maintenance, and use of devices and systems that vent combustion gases and pressures resulting from a deflagration (explosion) within an enclosure so the structural and mechanical damage is minimized.

It's technical! To ensure compliance, work with a trained expert who knows these standards well, keeps up with the latest revisions, and how they apply to industrial dust collectors.

Case Study: Dust Collection in Plasma and Wire Spray Operations

Read about one company in Atlanta, GA that was experiencing problems collecting metal dusts from a plasma and wire spray operation that produces metal coatings for rolls used in the printing industry - and how switching to the right type of cartridge dust collector reduced downtime and disposal costs.

This type of application can be very challenging. Various types of wires made of 316 stainless steel, Monel® alloy, zinc, and other materials are fed into the spray gun two at a time. The wire spray gun is fed with a compressed air line. The compressed air blows through these wires as they cross, creating an arc that blasts the wire onto the roll to form the coating. The wire spray is very fine, mostly submicron particulate and is inconsistent in shape, causing a difficult challenge for the dust collector.

This published article can be very helpful if you have a similar application. Read the entire case study Dust Collection in Plasma and Wire Spray Operations.

Dust/Fume Collectors for Laser/Plasma Cutting

CNC plasma tables and laser tables generate molten metal and smoke that is pulled down through the grate. The smoke is then removed through the duct work and filtered through the dust collector.

In these applications, a channel baffle inlet should be used to help deflect any sparks that make it to the collector. For safety, spark detection and suppression should be considered in extreme cases. Fire retardant cartridges should always be used in this application, as well as sprinkler heads in the collector itself.

Explosion vents should also be included when cutting aluminum. The collector should be located outside. It is best to check with your insurance carrier and follow the NFPA 654 Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing and Handling of Combustible Particle Solids. Continue reading here...

Understanding Your Dust: Six Steps...

Almost every piece of process equipment in a powder and bulk solids handling plant depends on a dust collector to safely control dust or to reclaim valuable product. So why do most users treat dust collector selection as a mysterious art rather than scientific process, without considering exactly what kind of dust they need to collect and what performance they need?

The article Understanding Your Dust: Six Steps to Better Dust Collection helps take the mystery out of the process by explaining how to analyze your application needs and dust characteristics as part of choosing a dust collector. Sections detail the six steps in this process.

Combustible Dust Training Videos

The NADCA (North American Die Casting Association) has posted a series of informative training videos on YouTube regarding combustible dust. These cover a variety of subjects from fire prevention to employee evacuation to controlling ignition sources.

One of these videos, specific to industrial dust collectors, can be viewed here: Combustible Dust Training - Section 3 - Dust Collection. Watch especially for the information starting about 1 minute into this video. The more informed you are about combustible dust when making a dust collector purchase decision, the better.

Dust Collectors for Food Processing

The type of dust collector suitable for food processing applications can vary. Dust collection applications include dried food ingredients from coarse grains to fine spices and additives. For sugars and other sticky dusts, specialized filter cartridges are probably necessary.

A clean food processing facility is vital for worker and visitor safety. Slips and falls are a constant concern for anyone running a food processing business. Flours, corn starch and other starches can be explosive. Read more on Dust Collectors for Food Processing...

Recirculating Air From Dust Collectors

Whether dust collectors are used in a plant to control indoor air quality (IAQ), keep equipment clean, and/or recover high-value process dusts, many plants are considering recirculating the air back into the plant downstream of collectors instead of exhausting it outdoors. When using recirculating dust collection systems, special safety and performance concerns must be addressed.

The article Recirculating Air From Dust Collectors is a classic composition that explores the benefits of recirculating indoor air as well as the safety issues.

Dust Collector Self-Cleaning Filters?... How?

Industrial dust collectors with media filter cartridges typically have a mechanism or system built in to keep the filters from blinding (clogging up with dust). Naturally, it won't keep the filters clean forever, but an efficient system will greatly prolong their life and keep the collector operating effectively.

Older technologies included vibration, shaking and even banging to dislodge accumulated dust from the filters. Most modern systems use air blown through the filters in the reverse direction of the normal airflow through the collector as it's collecting dust. This more efficiently dislodges dust from within the pleated media pack. Not all filters in the collector are reverse blown at the same time. This allows the dust collector to continue to run, doing its job of collecting dust while cleaning of the filters can occur at a continuous or intermittent interval.

In most cases, this reverse air is pulsed (a short blast like 0.15 second). Here is a video demonstrating the reverse pulse cleaning of filter cartridges inside a dust collector. (The filter access door, normally closed, was left open for this demonstration.)

Learn more here about efficient pulse cleaning inside a cartridge dust collector . Refer to figure 6 and the article text around it.

Dust Collectors for Chemical Processing

Pesticides, paint pigments, agricultural dry chemicals - from ingestible powedered drugs to mouse poisions, each dust collection application will present specific concerns. Filter media is especially important for chemical processing.

This web page focuses on collecting dust in chemical processing applications. Linked is an informative article on chem.info entitled "How to Tackle Combustible Dust With Successful Dust Control Systems."

Collecting and Testing Dust

Testing dust is beneficial in many ways. By identifying the dust characteristics properly, you can determine the right type of collector (such as baghouse or cartridge system) and filtration media for your needs and determine the size equipment you need for optimial energy savings and operational efficiency. By using the right equipment, you can minimize maintenance problems and reduce emissioins while extending filter life.

The article Collecting and Testing Dust emphasizes the scientific approach to dust and fume collection by using dust sample testing as the basis for sound and accurate equipment selection. More often than not, equipment decisions are based solely on guesswork, on previous experience, or on general recommendation from suppliers. Finding the right dust collection system is a complex task affected by dozens of variables. The situation does not lend itself to guessing games.

This article, Collecting and Testing Dust, is also downloadable as a PDF file.