"Most people view buying dust collection equipment as a necessary evil because they can't really put a price tag on the payback," says Rusty Angel. "If you have a moulder, you can calculate how many board feet you can run in a given year and what the profit is on those board feet. You get payback."
In a recent interview, Angel, national sales manager for DISA, a maker of dust collection equipment, discussed some operational and product quality benefits to using the proper equipment, mistakes companies make when buying systems and enhancements that will improve future systems.
A major benefit in improved dust collection is increased machine life. "The inner workings of a widebelt sander or a moulder with no dust collection are going to become caked with dust," Angel says. "Improved collection can increase machine life, so you have a longer payback."
Improved dust collection also typically makes for a better product. On a moulder there usually won't be knife marks where the chips are coming back around on the cutter head and denting the product. On a widebelt sander that is sanding flat cabinet doors, there won't be dust laying on the doors creating imperfections.
"Not every shop in America has the luxury of having an entirely enclosed finishing area or finishing system, so a lot of the plants we go into have their finishing system over in one corner and it's open," Angel says. "If you've got ambient dust floating around in the facility, you're going to get an inferior product because you're going to have an imperfect finish when you go to spray."
What kind of mistakes do companies make when specifying and buying a dust collection system? First, Angel says that companies tend to be too price conscious, in part because they can't see a payback measured in dollars, as already mentioned. So they try to cut corners, and he says dust collection is no different than any other machine - you get what you pay for.
"You can try to cut corners by using lighter duty ductwork, by using a fan that's slightly less efficient or by trying to overload the filter, but that usually ends up costing in the end," he says.
"No one budgets properly for dust collection equipment. Our rule of thumb is that a standard system that includes the dust collector, ductwork and installation usually runs between $4 and $4.50 per cfm. If you've got a company that needs 10,000 cfm and it just needs a dust collector, ductwork and complete installation, it's going to run about $40,000. Now, if it's more of a technologically advanced system with all the spark detection equipment and the abort gates, some of these systems can approach $6 per cfm. But a good rule of thumb for the average woodworker would be somewhere around $4 per cfm for everything he would need to get up and going with a system."
He says another common mistake is trying to find a used collector that will meet a company's needs. "It's very difficult to find a used collector that's in any kind of decent shape whatsoever. And it's almost impossible to find a dust collector that is sized properly for a given individual's needs. In other words, you may go out on the market and find a 20,000 cfm dust collector, but you need 5,000 or 30,000 cfm. It's very difficult to make it work if you buy the wrong thing."
Angel says there is no rule of thumb regarding the capacity of collector needed for a certain number of machines or size of plant. "We have done plants that have three machines in them that have a 25,000 cfm system. We've also done plants that have three machines that are 2,500 cfm. We have a customer that has Weinig moulders and a gang rip saw and they've got a 25,000 cfm dust collection system. Then we have companies that are smaller, have 20 or 25 machines, and they also have a 25,000 cfm system. They've got a jointer, table saw and shaper, like a typical architectural millwork or cabinet shop, and they're only running two-thirds of the equipment at any given time so it's very difficult to put a rule of thumb on that type of thing."
Fine dust collection
Angel says that two things have increased the need for efficient fine dust collection. One is the use of sander sealer, because that tends to produce a very fine dust. The second is the growing use of solid surface.
"We're seeing more and more cabinet shops, and some architectural millwork shops, working with Corian and other types of solid surface," Angel says. He says this presents some very unusual challenges and requires a different design in the dust collection system.
"We would install a larger baghouse than we would in the typical woodworking application in order to give the customer more filtration area," says Angel. The more filtration area you have in a given baghouse, the higher the filter area and the better efficiency you're going to get in filtration."
In any solid surface shop, Angel believes one of the first three or four things that should be considered is the dust collection system. "I know that sounds a bit self-serving to our industry, but I've been in 40 or 50 solid surface shops in the last two years and many are an absolute mess," he says.
Then there are the health considerations. Angel says that although wood dust is classified as a carcinogen, this is not really a hot button for most people. What is a concern, however, are more strict regulations set forth by EPA and OSHA, such as EPA regulations that require most dust collectors to be 99 percent efficient down to 10 microns.
Angel says that the dust collection manufacturers have improved their systems in several ways. In the past, for example, most people had dust collection built around cyclones that were not very efficient and could not return air back into the plant. In the last 15 to 20 years there has been a shift from cyclones to more efficient baghouse designs.
"We have improved the design of the dust collectors by having fabric filter media in some of them and cotton or polyester so that the filtration efficiency is such that you can actually bring the air back inside the plant," he says. "That's critical in Northern plants because during the winter months if you're pulling all your dirty air outside and not bringing it back inside it's very hard to keep the plant warm."
Also, Angel says that dust collection systems have improved because the woodworking machinery manufacturers have done a better job of recognizing that improper dust collection reduces the efficiency of their equipment, so they've done a better job setting their equipment up for dust collection with things like better hoods and improved dust collection ports.
Angel says that 75 to 80 percent of DISA's dust collection business is in the woodworking industry, and they have a good working relationship with many of the major suppliers.
"We talk to Weinig engineers about the design of their hoods and the extraction ports around the cutter heads on all their moulders," Angel says. "We've got a program where we supply them with a custom manifold for their equipment, and we educate them and their technicians on how important dust collection needs to be for a better product."
In the future, Angel sees better control systems with more automation. More customers are tying the operation of their dust collector into their equipment with things like automatic blast gates, which turn on the dust collection when the machine is turned on.
Also, he thinks that the industry is moving toward a safer approach, with features like spark detection equipment and abort gates.
"Basically what abort gates do is if you've got a dust collector sitting outside and are returning the air back into the facility, then the spark detection equipment detects a spark and attempts to extinguish it with water," he says. "If that is not successful and that spark gets by the water stream, then another set of detectors picks up the spark and then throws the abort gate so that all of the air is aborted outside."
He says the NFPA has encouraged dust collection manufacturers to change their approach to keep up with changing regulations. In addition, governmental agencies and local municipalities are becoming more stringent on their emissions control requirements on dust collectors.
Even though there have been major changes in environmental regulations, many municipalities and governmental organizations don't have enough agents to inspect every plant.
When they do go into a plant that isn't complying with regulations, Angel says they will tell that company they have 30, 60 or 90 days to fix the problem or they will be shut down.
"Probably two to five times a year we have to work with a customer on that basis," he says.
"They call us in, 'Hey, EPA has been in here, I'm not within compliance, I've got to do something quickly,' But it doesn't happen that often."
Expandable and custom
Angel says that one of DISA's features is its expandable dust collector system.
"This has really been a benefit because the woodworking industry is always changing," he says. People are upgrading their machines on a regular basis and our equipment lends itself to that because it's expandable.
"A customer with seven machines can buy a dust collector and we determine that their need is 20,000 cfm. We can put in that 20,000 cfm collector and a 20,000 cfm fan. Five years from now they buy two CNC routers that need 5,000 cfm apiece, so they need another 10,000 cfm.
"Because of the construction and the design of our collectors, we can add additional sections to the baghouse to increase its capacity, and we can add a second blower, so now they've got a 20,000 and a 10,000 cfm blower, and can run the ductwork from that 10,000 cfm blower into the two new routers. What they end up with is two fans blowing into one 30,000 cfm collector. The benefit is that they still have one common receptacle to collect the dust.
"We've been able to design a fully expandable and modular system that lends itself to that type of flexibility for the customer. We have probably a dozen expansions a year of any significant size where customers are coming back with three more pieces of equipment."
On a current installation, a 60,000 cfm system is divided into three zones with three fans to handle 75 machines. They can run those zones completely independently from one another or all together at the same time.
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