The impeller of the Model 9-19 high-pressure centrifugal fan is prone to heavy dust accumulation. This fan is equipped with backward-curved blades that easily trap deposited dust. In addition, the fan is arranged below the burner, so flying sand and debris falling from the furnace inlet tend to adhere to the blades, destroying the dynamic balance of the impeller and resulting in severe fan vibration.

First, reform the burner sealing structure: replace the original single-layer graphite block seal with a fish-scale contact seal, which drastically reduces the amount of sand splashing toward the burner and eliminates air leakage of the Model 9-19 fan. A small amount of falling sand will directly fall onto the access door for regular manual cleaning. Second, implement scheduled maintenance or shutdown arrangements to periodically remove dust from fan blades, ensuring stable operation of the Model 9-19 high-pressure centrifugal fan. Third, reconstruct the fan inlet: modify the original horizontal air inlet to a downward-oriented inlet. Although this slightly increases air intake resistance, the cleanliness of intake air is greatly improved. After implementation of the above countermeasures, vibration induced by dust buildup on the fan impeller is significantly suppressed, realizing stable unit operation.

Excessive overhang length of the inward-extended shaft leads to excessive bearing load. Compared with the Japanese 540 mmH counterpart, the overly long cantilever shaft causes localized stress defects and bearing damage. Combined with fan structural characteristics and on-site installation conditions, the impeller-side bearing housing is moved 100 mm toward the fan casing to shorten the cantilever span of the fan-side bearing, substantially optimizing bearing stress distribution.

After the above structural modifications for the Model 9-19 high-pressure centrifugal fan, the service life of fan bearings is extended to more than one year. No similar failures or unplanned shutdowns have occurred during years of standby operation. Meanwhile, spare rotor assemblies for the Model 9-19 fan are manufactured for periodic replacement, with replaced rotors kept as spares, so continuous stable and reliable operation of the equipment is effectively guaranteed.