Quality of Key Components and Assembly for 919 High-Pressure Centrifugal Fans

Quality of Key Components and Assembly for 919 High-Pressure Centrifugal Fans

The propeller design varies depending on the specific 919 high-pressure centrifugal fan model. Typically, impellers in smaller 919 high-pressure centrifugal fan units are almost exclusively single-suction, while larger fans predominantly feature double-suction impellers. The impeller consists of a front plate, rear plate (in double-suction types), center plate, hub, blades, and other components. For 919 high-pressure centrifugal fan installations, the maintenance of impeller assemblies and quality standards for each component must meet the following conditions: 1. If impeller wear is detected, the worn section can be cut off and repaired with new material. The worn area should be ground with an angle grinder before welding. However, attention must be paid to eliminating thermal deformation and welding stresses during the welding process. 2. When the blades of the 919 high-pressure centrifugal fan are found to be excessively thin (typically 30% of the original thickness), new blades must be replaced promptly. The installation tolerance of the new blades must meet the relevant data requirements. 3. After replacing blades, implement appropriate wear-resistant measures based on airborne dust concentration, particle properties, and the airflow trajectory between blades and intermediate plates. When bonding ceramic plates to the blades of the 919 high-pressure centrifugal fan assembly, the ceramic plate material must be micro-pulverized. The sintered hardness must exceed RC85, and the ceramic plate thickness must be below 3mm. Bonding agent: Shear strength ≥ 250 kgf/cm², melting point ≥ 150°C. When using thermal spraying, employ refractory alloy materials with a layer thickness not exceeding 2 mm. When welding wear-resistant alloys or cemented carbides, orient the welded carbide layer perpendicular to the airflow direction. If the wear of the front and rear discs exceeds 40% of their original thickness, the propeller centrifugal fan must be replaced with a new one. In addition to the above requirements, if wear is detected on the welded shims of the impeller in the 919 high-pressure centrifugal fan unit, repairs are necessary. If cracks are present, the damaged section must be removed. After machining the V-shaped groove, welding must be performed according to the relevant welding procedures.