Q. What are the factors to consider in choosing dust collectors?
A. There are numerous factors to consider:
1. The first factor is dust type: Is it hygroscopic, soluble in water, sticky, flammable, hazardous, explosive? Also, are fumes present? If dusts are hygroscopic or sticky, it’s important that it not clog under any operating condition. A bag house dust collector can clog when material is sticky, or when humidity rises, so these applications are best served with a wet dust collector. Fumes are often present in metalworking shops, and a dust collector that can do “double duty” with dusts and fumes is an excellent answer.
2. Second factor involves characteristics of particles: Are there thin fibers, ragged edges (such as metal fines), something else? Some dust collection systems involve fabric that can wear quickly when exposed to some dusts.
3. Is material entering corrosive? This eliminates several options. If dust is corrosive, a polypropylene dust collector is the best alternative – unless there’s high heat.
4. Fourth factor is micron size, and whether particle size is uniform. If any material entering the dust collector is “sub-micron” in size, that affects the choice of the system, too. Where there is a very broad range of micron size dust, a combination CCS and Whirl Wet installation will capture virtually all dusts with efficiencies in the range of 99% and above.
5. Fifth is capacity: will the dust collection system capture 3 lbs. per hour, or 3 per day? The issue is maintenance: how often the it needs to be dumped. If weight and density are known, dump intervals can be calculated quickly. If loadings are high, one answer is a “24/7” MCD unit dust collector that operates without shutdown.
6. Will there be multiple sources ducted to one unit? Some dust collecton systems will accommodate numerous sources of similar dusts, the only equipment limitation being a change in static pressure.
7. If dust quantity is large, how important is it that it operates “24/7”, even during maintenance? Many processes can’t accommodate shutdowns, even for brief periods. Where this is the case, disposal can be automated with an MCD system.
8. Will the it need to operate above 99% efficiency? If high efficiency is required for OSHA or IAQ reasons, a wet dust collector that uses very little water, but is consistently able to perform at this level, is specified.
9. Is it mainly for regulatory or insurance reasons? Or, will the system be purchased to save on maintenance, or improve IAQ? Dry systems should not be used where dusts - or dusts that could be a factor in the future – are at all volatile. A wet dust collector eliminates the risks of sparks and spontaneous reactions. A wet or dry unit will improve IAQ.
10. Will it be installed in a region where water is expensive? If so, dust collection system that uses very little water is best. The most efficient wet dust collector available consumes only enough water to compensate for drag-out (a small amount) and evaporation.
11. Is it important the collection system be easy to maintain? If so, a unit that’s self-cleaning is preferable. There is a low-water use wet dust collector available that has no internal moving parts and is self-cleaning.
12. Is it important that it be inexpensive to maintain? If so, a dust collector that doesn’t use consumable parts is preferable. The most common complaint about baghouses is . . . bags! - and the other maintenance parts that are involved with a system involving bag-changing. For a wet dust collector, spray nozzles and pumps add costs to the operation of the dust collector. The exception is a wet dust collector that does not use spray nozzles or pumps.
13. Does the facility prefer to generate a compact filter cake or dense slurry, or just bags of dust? Most plant managers now prefer dust collectors that minimize the volume of material that must be disposed of by producing a relatively small filter cake, is preferable. It is also preferable because the cake or slurry is fully contained and manageable, and does not create issues with fugitive emissions.
14. Is it important that it operates quietly? Many companies require that new equipment meet low-noise standards, for reasons of employee health, and productivity. A Tri-Mer dust collection system installed at DaimlerChrysler Tech Center in Michigan emits just 75db at 3 ft – well within “low noise” standards.
15. Does the system being considered have a documented uptime performance record for similar installations? Always ask! There are more than 540 Whirl Wet dust collection units installed worldwide. No matter what the application, Tri-Mer can show you a “real world” system that’s doing what you require.
16. Will material from the unit be recycled? Product recovery is important for applications such as titanium and other exotic metal dusts. Some systems designs facilitate recovery, producing substantial costs savings.
17. Are there space limitations? Where space is limited, equipment that can be installed on a mezzanine, or with the fan out-of-doors, is helpful.
