(1) Design reason: the fan is generally designed according to the service environment, temperature, air volume, air pressure and medium of the fan, but some enterprises do not select the type according to these factors, resulting in the following factors: improper fan design, poor dynamic characteristics and vibration during operation; Unreasonable structure and stress concentration; The design working speed is close to or falls into the critical speed zone; Inaccurate calculation of thermal expansion leads to poor alignment in hot state, etc.
(2) Manufacturing reasons: the quality requirements of the fan manufacturer also affect the operation of the fan, such as poor processing and manufacturing of parts and insufficient accuracy; Poor material, insufficient strength and manufacturing defects of parts; The rotor dynamic balance does not meet the technical requirements, etc.
(3) Reasons for installation and maintenance: the installation accuracy requirements of the fan play a vital role in the operation of the fan. If the installation accuracy does not meet the installation requirements, it will damage the operation of the fan. In the process of fan installation, there are the following influencing factors, such as improper mechanical installation, misplaced parts and large preload; Poor alignment of shafting; Improper adjustment of machine geometric parameters (such as fit clearance, interference and relative position); The rotor is placed improperly for a long time, which changes the dynamic balance accuracy; Failure to maintain according to the regulations destroys the original matching nature and accuracy of the machine.
(4) Operation reason: during the use of the fan, the maintenance of the fan plays a decisive role in the operation quality of the fan. For example, the process parameters (such as medium temperature, pressure, flow, load, etc.) deviate from the design value, and the operation condition of the machine is abnormal; The operation of the machine under over speed and overload changes the working characteristics of the machine; Poor lubrication or cooling; Local damage or scaling of rotor; Improper operation during startup and shutdown or speed rise and fall, uneven thermal expansion or too long stay in the critical area, etc.
(5) Reasons for machine deterioration: general equipment has a certain service life, and the performance of the equipment will deteriorate when it reaches a certain service life. The same is true for fans, such as: long-term operation, increased rotor deflection or deterioration of dynamic balance; The rotor is partially damaged, fallen off or cracked; Wear, pitting or corrosion of parts; The stress on the mating surface deteriorates, resulting in insufficient interference or looseness, which destroys the mating property and accuracy; Uneven settlement of machine foundation and deformation of machine shell.
