Cooling tower fan blades should be inspected as part of a complete inspection of the cooling tower. The blades are typically inspected during planned shutdowns and by having a good idea of what to look for will make the inspection more valuable. A leading manufacturer recommends no longer than one year intervals for inspections. While not all blades are constructed or installed in the same way, this paper will address the most popular type of construction, installation and the known hazards. A familiarity of your blades and recommendations of your cooling tower specialist are strongly encouraged. The blades should be first checked for structural integrity. One of the possible issues is that the blade can become loose at the mounting point or hub. This check may done by holding the blade at the end and checking for movement or play at the hub. If movement is felt at the hub or you can change pitch the blade needs to have the pitch, track and torque reset according to manufactures specifications. It should also be checked for areas that are soft or brittle. If not possible to remove the play the blade must be replaced.1 Hub damage is unrepairable see Figure 1 Another possible type of damage is splits in the trailing edge. Check to see if the split goes completely through with a blade at least 2 inches long. If the split goes completely through, the blade must be replaced. Splits cannot and should not be repaired.
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