CWB debuts a new feature, asking dust collector manufacturers about the latest developments and how to maintain efficiency.

1) What is the latest development in dust collection equipment? (If you are talking about a specific type of dust collector, rather than in general, please specify which type, i.e., cyclone, bag house, cartridge, etc.)

Steve McDaniel, vice president, Kirk & Blum Product Division, K&B Duct: Several of our dealers have alerted us to new regulations that are requiring dust duct systems to have a back-blast/abort gate installed between the collector and the inside duct to prevent any fire/explosion from returning into the work area. This is being driven by the disaster in the sugar plant blast last year. These gates must both close off the air to the plant and vent the explosion to atmosphere. We have such a devise.

Jamison Scott, director of marketing, Air Handling Systems: Most manufacturers are focused on lean manufacturing and eliminating waste in the manufacturing process. Dust collection is essential in a lean program. Efficiency of workflow is aided by proper dust collection. For example a central dust collection system focuses on a central waste source rather than individual collectors, which wastes time in emptying separate barrels of dust. A properly designed and sized dust collection system also focuses on energy efficiency. A system too large or too small is wasting precious resources.

Mike Gerardi, general manager, Scientific Dust Collectors: In general, the latest development in baghouse and cartridge collectors has been the promotion and advertising of nanofiber media material technology used in both cartridge and baghouse collectors that have the ability for improved "surface loading" rather than "depth loading" of dust particles. In this way, the dust cake performs better and the media (filters) last longer. More specifically, for our company, we have just completed years of development of an improved nozzle that provides a significant positive impact on how the media is cleaned in both a baghouse and cartridge collector. The better the media is cleaned the more process air you can pass through it and the longer the media lasts. Using our baghouse in wood dust applications, we guarantee at least a four-year bag life. That is unique in the industry. That benefit is due to our special cleaning technology.

Eric Lowe, national sales manager, Dantherm: The need for cost and energy efficient dust collection systems has never been greater. Energy required for dust collection is often times the second largest consumer of a plant’s electricity usage, second only to the process equipment the dust collection system is serving. Laser welded, clamp together ducting and logic controlled blast gate systems are two of the more recent developments in dust collection equipment that greatly assist plants to get the best efficiency from their dust collection systems.

-Laser welded, clamp-together ducting
Laser welded, clamp together ducting provides tight and leak proof seams, combined with smooth inner surfaces that provide less friction and less opportunities for dust or wood fragments to clog in the duct. In larger plants, with long runs of dust collection ducts, elimination of friction in the duct can contribute to a significant reduction in horsepower consumption by the dust exhaust fan. This provides substantial yearly savings. The clamp together design also allows for easy removal and cleaning of clogged portions of ducts which many times are ignored in plants until a shutdown is required to remove the clog. Installation, relocation and retrofitting of clamp together ducting is also so fast, simple and easy that plant personnel can perform them without having any special machinery, materials or skills.

-Blast gate systems
In this difficult economy, many plants are looking for ways to eliminate inefficient and unnecessary equipment and maintain the good equipment that they have. The standard dust collection design has been to size a system for the total number of machines needing dust collection in the plant, when in most cases less than 50% of the machines are actually running at any one time. Then, why have your dust collection running on all machines all the time?

An EMS (energy management system) with logic controlled blast gates can provide a means for the customer to match his dust collection requirements to his actual machine usage. After careful design, installation and startup, an EMS gate system can dynamically match the plants’ dust collection requirements. The blast gates are used to “shut down” the flow of un-needed dust collection and exhaust only the amount of exhaust air required for the present operating conditions.

By employing EMS gate technology a plant can reduce their amount of exhaust air and save up to 60% on their energy costs. In the cases where the plants must condition the makeup air this results in even more energy savings.

Another benefit of this system is that when the dust collector is operating at a reduced flow, the filter speed (air to cloth ratio) is significantly reduced, resulting in higher filtration efficiencies and increased filter life.

Finally, these techniques not only reduce your demand for energy, they also allow you the option to either use a smaller collector or have a collector larger than your current needs, but ready for future expansion.

John McConegly, president, JDS Co.: Cyclone collectors are more popular now, smaller cyclones that can be put inside a facility. Older collectors are too large. Companies don’t have the same amount of woodworking machines – dedicated dust collectors for individual machines run less and are more effective for demand.

Movement inside the dust collectors has led to new developments in equipment. Higher efficiency bags have become popular. Pleated canister filters are more popular. Customers are more concerned about the air coming out of the machine.

Static pressure is another concern. The addition of 90 degree turns increases static pressure. Some collectors will see diminishing performance with increased static pressure.

Rick Bush, product development manager, Festool: Let me preface this by first classifying dust extractors as portable dust extraction systems for use with Festool portable power tools.

Consumers have become more cognizant of the long-term effects and potential hazards of the materials they are routing, sawing and sanding. They are demanding higher levels of dust extraction and filtration. To be effective, dust extraction must start with the design of the machine or tool from which you are collecting. The tool or machine must be designed to optimize the flow of air, while taking into consideration the nature of the cutting tool or abrasive surface. When taken into consideration in the initial stages of the product design, dust extraction efficiency can be made priority. Adequate suction force is also required to support the needs of the individual machine or tool. Festool specializes in portable power tools and the dust extraction needs of those tools. We feature electronic variable suction force to ensure a match between the suction needs of the tool and application for which it is being used. Festool employs highly efficient HEPA filtration in our larger dust extraction units so the air being exhausted is generally much cleaner than the air in the work area.

Robert Witter, owner, Oneida: Oneida Air has developed a small portable hybrid vacuum/dust collector that combines the benefits of both into one unit. The Dust Cobra can work in applications where dust collectors or standard vacuums don’t work well. The dust cobra is suitable for panel saws, panel routers, tools that require high suction, portable wood working tools, job site dust collection and general shop clean up.

2) What is the most important step your customers can take to make sure their dust collection equipment runs smoothly?

McDaniel: As our customers' sales drop, the interest in cost cutting measures is increasing. Dust collections fans typically are the highest consumer of electricity in the plant, often running up the cost per Kw on all machines because the rate is based on peak requirements. Therefore as a high horse power fan comes on line, it sets a high peak and this sets a high rate for the entire plant. Variable frequency drives (VFDs) can serve two purposes. One, they bring the fan on line slowly — lowering the peak amperage. Second, VFDs tied to a simple manometer (vacuum sensor) can modulate the fan in such a way as to slow it down and speed it up as demand on the dust system changes. As blast gates are opened manually or automatically with the operation of the production equipment, the sensor senses the changes to the pressure in the duct and signals the VFD to respond to the increase or decrease in demand. Because most plants don't have all of their machinery running 100% of the time, few operations require 100% of the available power. Controlling the power has huge benefits. For example — a 10% reduction in the fans speed typically nets a 20% power savings and a 20% reduction nets a 40% savings. We have the ability to consult on these systems as well as provide the entire solution, from automatic gates to VFD, controls and installation.

Scott: As mentioned above a properly designed and sized system, which is installed with minimal air leakage, facilitates a smooth operation.

Gerardi: I believe the best benefit to the user is to make sure he monitors the differential pressure gauge on a regular basis. This gauge will measure the pressure drop between the clean side of the collector and the dirty side of the collector. This is really the only way to determine how your dust collector is performing. If an event occurs that causes the pressure drop to jump, then possibly there is a problem with the air compressor, air dryer or collector cleaning components such as valves, timer board or solenoids. In this way, the problem is resolved early enough before the filters are past the point of not being able to recover.

Lowe: The key to smooth running dust collection systems is routine maintenance and proper sizing of the system. The dust collection collects the dirt, dust and particles that you want to keep from the rest of the machinery and especially the personnel operating this machinery. This harsh environment requires effective and timely preventative maintenance on all aspects of the system. Improper and ineffective maintenance can lead to premature failure and in some cases fires or explosions.

To prevent dust collection systems from becoming the source of downtime and compliance issues, it is imperative that you budget for a professional preventative maintenance program. Service professionals can perform your routine maintenance and identify and correct any small problems, before they become big headaches. In addition to the need for routine maintenance, during the long life of a dust collection system many variables, such as: process components, types of materials processed and the number and type of machines utilizing dust collect can change. Service professionals can show you how to modify your system to meet new process and capacity requirements and how to optimize your system to achieve the highest operating efficiency possible.

Dust collection manufacturers provide access to service networks that are knowledgeable and dedicated to this industry. The manufacturer should be consulted to identify the best possible service companies to help plants with this important process.

McConegly: Customers need to understand the system they have. How the system is laid out is important to performance. More pipe, smaller pipe, and more bends equal reduced performance. Choking the performance with too many bends is similar to traffic movement on the interstate – with sweeping bends, the air moves faster. A customer doesn’t need a bigger dust collector to be more effective, it could be a case of needing a more efficient ducting system.

Bush: Dust extraction is easy to take for granted until it stops working. Light maintenance is all that is needed to keep your system breathing. Occasional visual inspections of ports and hoses is a good first step. Look for partially blocked ports or extraction points. Also, inspect for abrasions or tearing on or in the hose for potential sources of leaking. Next, inspect the collection bags and filters for tears or clogging which may reduce suction force as well as extraction efficiency. Tears in the collection bags or filters my also shorten the life of the extractor. Finally, inspect the collection bag to make sure it is not full. It is easy to overlook the need for a replacement bag until the existing one is full. Always keep clean serviceable bags on hand.

Witter: The most common problem performance problem we see is insufficient filter area for the air volume (CFM) rating of the dust collection system. For chronic complaints on low air performance and premature filter blinding (clogging) the first thing we look for is too high an air to cloth ratio. Use sufficient filter area for the air volume or CFM of the system. Low air to cloth ratios allow air to move slowly across the filter media keeping the pressure drop or energy loss to a minimum. As filters load with dust cake pressure drop across the filter media increases and the overall system airflow decreases. Keeping pressure drop across the filter low will result in less overall system energy costs and the dust collection at your woodworking tools will be better. For smaller manually cleaned systems set a regular cleaning maintenance schedule for your filters. For cloth filter systems the general industry standard for wood dust is a ratio of less than 10:1. This means at least one square foot of filter for each 10 CFM of air volume.