Swaim and Associates
Cartridge CollectorModular BaghousePortable CollectorAirlockBig Round BaghouseCycloneDiverter ValveDowndraft Table

4 Steps to Successful Dust Collection

A good dust collection system is vital to any manufacturing process that creates nuisance dust which are harmful or unsafe when accumulated in an enclosed environment. It is often that the dust collection system is overlooked, or an afterthought, when plans are made for new facilities or expansions. The dust system must be brought into consideration when designing and budgeting to allow for a safe and clean manufacturing facility as well as to extend the life and decrease the maintenance of your expensive process machinery. There are four main points when considering a dust collection system:

  1. Selecting your dust collector (i.e., baghouse, cartridge, cyclone, etc.)
  2. Sizing your dust collector
  3. Placement of your dust collector
  4. Dispsing of your waste

Step 1: Selecting Your Dust Collector

The first decision that must be made when purchasing a dust collection system is what kind of dust collector do I need? There are three main types of dust collectors:

  1. Baghouse dust collector
  2. Cartridge dust collector
  3. Cyclone material separato

The baghouse dust collector may be the most common. It is a very good solution which will filter the majority of the dust out of the air allowing you to return the clean air back to your building. This is very important in harsh climates where heating and or cooling cost need to be conserved. The baghouse dust collectors will have some type of cleaning system to clean the dirty filter bags when they get dirty. It is important to have clean filter bags so that the air can move freely through them. Popular cleaning methods are compressed air, reverse air, and shaking. The compressed air uses an air compressor to periodically fire an air pulse down the center of the bag on the clean side, knocking off the dust on the other side. The reverse air method is similar, but uses a fan to push air through the filters in the opposite direction thus removing the dust particles stuck on the bags. The shaking method is the most economical, but can only be done when the dust collector is turned off. The filter bags are shaken, which knocks off the dust from the dirty side of the bags. The cons of baghouse dust collectors are that they can be some of the more expensive options, and they can have larger foot prints and be taller making there placement difficult.

Cartridge collectors, like baghouse collectors, also filter the majority of the dust out of the air allowing you to return the clean air to the building. The cartridge dust collector is actually more efficient then baghouse collectors, able to filter down to much smaller particles. This can be important when dealing with very fine dust such as a fine sanding dust or a fume. The cartridge filters are cleaned only by compressed air. They generally have a smaller size making there placement easier. This is due to the cartridge design which allows you to have more filter media in one cartridge then multiple bags put together. The cons of cartridge collectors are that they can be one of the most expensive options and can have a hard time handling certain types of dust with heavy loadings.

The last type of dust collector is a cyclone separator. This style of dust collector is made to separate the particles by turning the airstream in a cyclonic motion inside a metal housing, allowing the heavier pieces to fall out of the bottom of the cyclone, while the clean air and some of the finer particles escape out the top. This method is not as efficient as the previous two types of collectors, as there are no actual filters. You can not return the exhaust air from a cyclone back into the building with out some type of after filter. This is the most simple and most economical design, as there is no need for cleaning systems. The cons to cyclones are that you can not return the air to the building with out a secondary after filter, and they do not provide 100% dust capture making there placement in populated areas difficult. (nobody wants a neighbor that is blowing fine saw dust all over there car)

Step 2: Sizing Your Dust Collector

The second and perhaps most confusing decision will be the size of dust collector needed. You will need to size the system big enough to handle all the air required to convey the contaminants away from the process machinery. The unit used when sizing a dust collection system is cubic feet per minute or cfm. Some manufactures will tell you how much cfm is required for proper dust extraction for their machinery. If you can not find a value from the manufacturer, but their is a dust port on the piece of equipment, you can assume the amount of cfm needed using a speed of 4500 feet per minute air velocity. In order for air to travel 4500 feet per minute through a 4" port, you need 395 cfm. If you have a 6" port on a machine, you would need 885 cfm to attain a 4500 feet per minute velocity. Please see the cfm calculation sheet for further instruction on different port sizes. If there is no dust port or you need to have dust extracted from an open area, you will need to contact a professional. Please contact us to determine proper air conveying volumes and speeds when in doubt. Once you know what each machine will require in cfm, you add the values to see how much total cfm you will need. Dust collectors are usually sized by this value, so now you will have an idea of what size dust collector to begin looking for.

**A way to save money**

If you are not going to need dust extraction at every machine or area at the same time, then you can undersize the system in order to save a little money. You can use blast gates or shut off valves in order to turn off machines or areas that do not need dust extraction at certain times. The best way to size a system like this is to first find your worst case scenario. What machines could possibly be running at the same time? When this is known, you can size the system to handle just that amount. One important consideration to look at when doing this is that your air velocity in the ductwork will be fast enough to convey material at all times. If too many machines are blast gated shut, then the amount of air traveling through the large trunk line in the ductwork may not be enough to carry dust airborn. This can cause dust to settle resulting in a bad fire hazard. The weight of accumulated dust in ductwork could also damage the ductwork itself. Once again, please contact one of our engineers for layout design assistance.

Step 3: Placement of Your Dust Collector

The third big consideration when purchasing a dust collection system is the placement of the collector. This can make a huge difference on your budget because it affects the amount of pipe necessary to connect the process machinery to the collector. The most economical place for a dust collector is inside the building as close to the machinery as possible. There are a few considerations that need to be addressed when placing a dust collector inside. Is it safe for the workers, and does it meet all applicable codes and regulations? If the dust being collected is flammable or explosive, there are regulations and codes that must be followed. If the dust collector is not enclosed, meaning the bags are exposed to the atmosphere, the collector may be placed inside. There may be a limit on the location to proximity of workers, size of collector, and type of machinery collected from, but in general it is usually acceptable. If the collector is enclosed, it must have explosion venting and fire protection installed. The explosion venting must be ducted outside or have a flame quench installed. You will need to check with your local fire, mechanical, and or electrical inspector for specific rules and guide lines. The safest placement of a dust collector is outside the building. When placing a dust collector outside, you should consider access to the area so that you can easily service your system components and dispose of the waste that is being collected. There are some areas where aesthetics will be in issue. you may have to consider smaller collectors that can be hidden when working in residential or some business park areas.

Step 4: Disposing of Your Waste

The last main consideration when purchasing a dust collection system, is what to do the with waste that is collected. There are some process where the amount of material collected is small and can be thrown away. There are many industries that produce larger amounts of waste making it costly and environmentally irresponsible to send the material to the landfill. The wood industry is a good example of an industry where the dust and shavings collected can be recycled and some times sold to be made into farm bedding, stove briquettes, and various other products. The material collected must be stored in a bin, dumpster, silo, or trailer of some sort. One method of collecting the material is to put the dust collector on a structure directly over the receptacle allowing the dust to be gravity fed into the storage vessel. Another design is to install a pneumatic relay system which uses a blower to push the material into a silo or trailer. The last method available is to use mechanical conveyors to more the material to the storage area. Augers, bucket conveyors, and drag conveyors are all used to mechanically convey material to different locations.

When deciding on a dust collection system, it is very important to consider all the above points to make sure you get a system that is designed correctly, and does what you need it to do in a cost effective manner. The benefits of purchasing a good dust system will pay for the extra money required by eliminating costly down time, house keeping cost, process machinery maintenance, and by allowing you to produce clean quality products in a safe and eco friendly environment.