Determining the Critical Speed of Explosion-Proof and Corrosion-Resistant Axial Flow Fans

Determining the Critical Speed of Explosion-Proof and Corrosion-Resistant Axial Flow Fans

What is the method for determining the critical speed of explosion-proof and corrosion-resistant axial flow fans? In this cold winter, no one wants to work in the freezing air; instead, everyone wants to rest in a warm room. In our view, that seems so simple, yet it dates back half a century. First, keeping a warm room from losing heat is straightforward, but people need to breathe. Therefore, they require a steady inflow of fresh air into the room. What about the cold air outside? The natural flow of air into the room inevitably lowers the indoor temperature and brings in cold drafts. Consequently, to meet people’s needs, explosion-proof and corrosion-resistant axial flow fans were developed. Regarding research on explosion-proof and corrosion-resistant axial fans, various improvements—such as their applications, structure, materials, and strength—were studied to establish new performance metrics. Only a few key aspects needed to be examined. First, for explosion-proof and corrosion-resistant axial fans, the critical speed—the maximum speed the fan can sustain during normal operation—must be determined. The calculation method for this critical speed can be derived from the following factors: The mass of the propeller and shaft, the span of the shaft between the two supports, and the distance from the center of gravity to the support points, as well as the initial diameter of the shaft and the maximum speed index set by the manufacturer, all require the input of various data points to calculate the shaft diameter, which is then specified for each fan. Substituting the obtained values into the critical speed formula yields the critical speed value. Furthermore, if the calculated value exceeds the permissible critical speed ratio, adjustments can be made to ensure safe operation.