Why Does Your Fan Matter?
Fans (or blowers) are used in almost every facility in one application or another. Many are used as part of a dust collection system, especially in feed mills. There are two important values when determining what fan to specify for a given application: cubic feet per minute and static pressure. Knowing what your air needs are will help ensure you choose the correct fan for your application.
Cubic feet per minute (or CFM) is a common way to express air needs. This is the amount of air (volume) that is provided over time. In order to achieve the desired effect, a certain amount of air is required to perform the job. In the case of a dust system, the air volume is sized based upon the equipment capacity. For something like a cleaner, a certain amount of air is required to remove the fine particles from the seed. If the volume is too low, it will not effectively clean the seed. If it’s too high, the volume may cause machine performance issues. Getting the right amount of air depends on application and capacity requirements.
Static pressure is a key aspect of fans that is often overlooked. CFM is important, but only half of the story. When putting a ducting system together, there are many things such as hoods, elbows, cyclones, and even the ducting itself that cause restrictions. These restrictions cause airflow disturbances, much like boulders or trees cause eddies in a river. These disturbances can impede fan performance if not taken into consideration. The fan’s static pressure rating (listed in inches of water) details how must restriction in flow the fan can overcome. For simple systems, the static rating can be 2-4 inches of water, but some systems, like for a counterflow cooler, require 20 or more inches of static. The rating varies based upon application, but again, needs to be sized appropriately.
Many fan vendors offer assistance to size fans accordingly. Each fan will have a performance curve showing these ratings. Based upon the system and application, various fan sizes, styles, and ratings are available. Knowing what the needs of the system are will ensure a correct fan is chosen.
Reach out to our team today if you have questions regarding best practices for fans in your facility.