DC Fans have been the go-to solution in a designer’s thermal management toolbox for years, providing efficient cooling for products requiring the removal of heat from a few watts to several hundred watts. To ensure that the appropriate fan is selected, it is important to align the system’s cooling needs with the fan’s airflow characteristics. …
Understanding Airflow Fundamentals for Proper DC Fan Selection Read More »
In addition to blade type, fans are typically organized by arrangement and operating characteristics. For most commercial and industrial applications, fans can usually be grouped into either housed-type fans or plenum-type fans. Each group has particular qualities which lend themselves to preferred or “best suited” applications. In order to understand these key operating characteristics, it …
Centrifugal Fan Arrangements and Application Considerations Read More »
A typical supply fan or impeller (wheel) can be described by the blade constructions. The distinguishing characteristic is the shape of the individual fan blades and their orientation relative to wheel rotation. The airfoil (AF) fan has contour blades that curve away from the direction of rotation. The backward incline (BI) fan is slightly less …
A centrifugal blower impeller have backward swept blades, radial tipped blades or forward swept blades as shown in figure: 1.1 below. The inlet and outlet velocity triangles are also shown accordingly in the figure. Under ideal conditions, the directions of the relative velocity vectors Vr1 and Vr2 are same as the blade angles at the …
Basic Principle Like most other rotating machinery, fans experience wear and require periodic maintenance and repairs. Dynamic surfaces in bearings and belt drives degrade over time. Fan blade surfaces may erode from abrasive particles in the airstream, and motors eventually require replacement or rewinding. Although some degree of wear is unavoidable, operating the system at …
The requirements for attaining a minimum level of fan energy efficiency and keeping the fan selection with an operating point close to the fan peak energy efficiency are being addressed in a recommendation for continuous maintenance proposal for ASHRAE/IES Standard 90.1. The proposal for this recommendation was made by ASHRAE Technical Committee 5.1, Fan Design …
Select Fans Using Fan Total Pressure to Save Energy Read More »
A centrifugal impeller with forward-curved blades produces more cfm and more static pressure at a given rpm than either radial or backward-curved impellers. Consequently, forward-curved centrifugal fans are popular in domestic equipment, where space is often at a premium and noise must be kept to a minimum. Forward-curved centrifugal fans display a typical “dip” in …
Maintenance Items Common maintenance tasks on fan systems include: Periodic inspection of all system components Bearing lubrication and replacement Belt tightening and replacement Motor repair or replacement Fan cleaning The most costly consequence of improper maintenance is unscheduled downtime. Causes of this downtime vary according to the demands of the application. Because each system places …