Maintenance Notes and Vibration Causes Summary for 9-19 High-Pressure Centrifugal Fans

Maintenance Notes and Vibration Causes Summary for 9-19 High-Pressure Centrifugal Fans

Before reusing the 9-19 high-pressure centrifugal fan after major overhaul, thoroughly inspect and verify all components. During operation, personnel must promptly remove dust and debris from the 9-19 high-pressure centrifugal fan and gas delivery pipelines to prevent corrosion. To ensure personal safety, maintenance of the 9-19 high-pressure centrifugal fan must be performed only when the equipment is shut down. During startup, shutdown, or operation, any abnormal phenomena should be investigated immediately. Promptly identify the cause of minor faults and take measures to eliminate them. If operational malfunctions are detected in the 9-19 high-pressure centrifugal fan, stop the machinery for repairs. Operating the 9-19 high-pressure centrifugal fan involves some complexity, and unexpected situations may occur. For instance, severe equipment vibration may be observed. This is typically caused by misalignment between the fan shaft and motor shaft. Additionally, friction between the fan casing inlet and impeller, insufficient rigidity of the impeller foundation, or loosening may also induce vibration. Beyond these causes, vibration can result from loose rivets on the inner impeller, impeller deformation, loose fit between the impeller shaft hub bore and shaft, or loosened coupling bolts. Furthermore, loose connections in the 9-19 high-pressure centrifugal fan equipment—such as bolts at the housing, bearing housing, and bracket joints—can also generate vibration. Moreover, if the blades of the 9-19 high-pressure centrifugal fan equipment accumulate dust or dirt, suffer wear, experience impeller deformation, or encounter shaft bending, the rotor will become unbalanced. Installation of forward-curved multi-wing fans must meet the following requirements Regarding the installation of forward-curved multi-wing fan equipment, attention must be paid not only to standard requirements but also to specific details. For instance, certain contact surfaces of the forward-curved multi-wing fan equipment should be coated with grease or engine oil to prevent rust and reduce disassembly difficulty. Additionally, during the bolting of mating surfaces, if locating pins are present, install the pins first before tightening the bolts. Beyond the above, ensure thorough inspection of the fan housing and other casings to remove any tools or debris. Remember: During installation, avoid placing the weight of gas flow ductwork on the fan casing. Adjust the clearance between the inlet and impeller per drawings, and maintain the shaft in a horizontal position. Note: If the centrifugal fan is installed at an angle, ensure the rear plate can rotate freely to keep the nameplate level. After installation, manually rotate the rotor using hands or a lever to check for excessive tightness or collisions. Only after confirming these points should trial operation proceed. During trial operation, personnel must also monitor bearing temperatures for normality. Under normal conditions, bearing temperature rise should not exceed 40°C above ambient temperature. Additionally, the root mean square (RMS) vibration velocity of bearing components must not exceed 6.3 mm/s. Should significant equipment vibration or abnormal bearing temperature increase occur, immediately stop the unit for inspection. To prevent motor burnout due to overload, personnel must start the forward-curved multi-wing fan equipment under no-load conditions.