A source capture solution is sized according to many variables. Dust collector capacity is a function of several factors:
- CFM: The air speed required for a source capture system—measured in cubic feet per minute (CMF)—is calculated in the design of any system. Operations with a high CFM will need more powerful motors than those with a lower air speed. Too little CFM won’t carry the particulates all the way to the dust collector; too much could drive the particulates too deeply into the filter media, clogging it. Maintaining a high CFM also costs more, due to the increased energy use. Fortunately, air quality engineers understand how to balance these variables and calculate the right CFM for your needs.
- Filter media: Filter media, measured in square inches, is the second element in dust collector design. The ration of airflow to filter media is called the “air-to-cloth ratio.” It is important to make sure you have enough filter media for the volume of particulates you produce and the total volume of air you are moving. Using too little filter media results in significantly shorter filter life, greater maintenance burden and more wear and tear on equipment.
- Motor horsepower: Source capture systems with large particulates or high volumes of dust require more horsepower from the dust collector.
Dust collector sizing depends on several factors:
- Distance from the source to the dust collector - The longer the distance, the more horsepower you will likely need from your motor.
- Particulate type - Fine particles require much less power and air speed than large particles. A lower air speed, measured in cubic feet per minute (CFM), means that less power is required and that operating costs will be lower.
- Volume of particulates - Some operations produce a high volume of particulates, requiring a lot of filter media.
- Pipe or duct diameter - Large particulates require larger diameter pipes and ducts, but there are limits to how large a pipe should be. If it is too large, there is a risk of particulates dropping out of the airflow. If this happens, it becomes a maintenance burden and perhaps a fire hazard.
Obviously, many of these variables are interrelated. For example, particulate type, CFM and motor horsepower are all connected. Professional air quality engineers are able to factor all of these variables into their design for a source capture system.