In various production enterprises and public facilities, centrifugal fans are mostly used as ventilation equipment. Generally speaking, when the fans leave the factory, the manufacturers will pre-assemble the various parts of the fans, and then transport them to the site for hoisting. However, after a period of use, It often needs to be disassembled, cleaned and repaired, and then installation errors may be caused during subsequent installations, resulting in reduced fan performance.
1)Acceptance standard for centrifugal fan installation
1. The installation of the whole centrifugal fan unit should be placed directly on the foundation and leveled with pairs of inclined horns.
2. For the fan unit assembled on site, the cutting surface on the base should be properly protected, and there should be no rust or operation. When the base is placed on the foundation, it should be leveled with a pair of inclined horns.
3. The bearing seat and the base should be closely connected, and the longitudinal non-levelness should not exceed 0.2/1000. Use a spirit level to measure on the main shaft, and the horizontal non-level base should not exceed 0.3/1000. Measurement.
4. Before grinding and scraping the bearing bush, the rotor axis line and the casing axis line should be corrected, and the gap between the impeller and the air inlet and the gap between the main shaft and the shaft hole of the rear side plate of the casing should be adjusted to make it conform to the equipment technology. document requirements.
5. When the main shaft and bearing bush are assembled, they should be checked according to the provisions of the equipment technical documents. An interference of 0.03~0.04 mm should be maintained between the bearing cover and the bearing pad (measure the outer diameter of the bearing pad and the inner diameter of the bearing seat).
6. When assembling the centrifugal fan casing, the position of the casing should be aligned with the rotor axis line as the benchmark, and the axial and radial clearances between the impeller air inlet and the casing air inlet should be adjusted to the level specified in the equipment technical documents. within the range, and also check whether the anchor bolts are tight.
7. If the equipment technical documents do not specify the clearance between the impeller air inlet and the casing air inlet, the general axial clearance should be 1/100 of the outer diameter of the impeller, the radial clearance should be evenly distributed, and the value should be the outer diameter of the impeller. 1.5/1000~3/1000 of the diameter (the one with the smaller outer diameter takes the larger value). When adjusting, try to make the gap smaller to improve the efficiency of the centrifugal fan.
8. When aligning the centrifugal fan, the different axial degrees of the fan shaft and the motor shaft, the radial positioning displacement should not exceed 0.05 mm, and the inclination should not exceed 0.2/1000.
9. For fans equipped with rolling bearings, the different axial degrees of the bearing holes on the two bearing frames can be subject to flexible rotation after the rotor is installed.
2) Centrifugal fan hoisting and installation methods and requirements
1. Installation method
(1) Ceiling installation: First install the fixed frame, then fix the fan to the hoisting position with bolts, and connect the pipeline to the fan outlet.
(2) Floor-mounted installation: It is also called horizontal installation. The centrifugal fan is fixed to the ground through the tripod of the centrifugal fan, and then the fan is bolted to the tripod to connect the pipeline and the fan outlet. .
(3) Roof-mounted installation: First correct the foundation level, then hoist the fan in the corresponding position to ensure that the joint surface between the fan and the foundation is naturally matched, and then fix the fan and the base of the roof with bolts. Ducts and fan outlets.
2. Lifting requirements
(1) For the integrally installed fan, the ropes for handling and hoisting shall not be tied to the rings of the rotor and the casing or bearing cover;
(2) For fans assembled on site, the binding of ropes shall not damage the surface of the machine parts, the central holes at both ends of the rotor and the gear shaft, the thrust surface of the bearing bush and the end face of the thrust plate. and the shaft seal should not be used as binding parts;
(3) The rotor and casing of the fan transporting special media are coated with a protective layer, which should be strictly protected and must not be damaged;
(4) The rotor and gear shaft should not be rolled or moved directly on the ground.