Thread Content
Inspection and maintenance of Roots blowers 1. Inspection and quality standards 1.1 Preparations before disassembly 1.1.1 Understand the operating conditions of the blower and have all necessary drawings and documents ready. 1.1.2 Prepare all maintenance tools, measuring instruments, lifting equipment, spare parts, and materials. 1.1.3 Cut off the power supply; the process conditions meet the requirements for safe maintenance. 1.2 Disassembly and Inspection 1.2.1 Remove all accessories from the fan and check the gaps between the rotors as well as between the rotors and the side walls. 1.2.2 Remove the coupling or pulley, and inspect the elastic ring or V-belt. 1.2.3 Disassemble the gearbox, inspect the tooth surfaces and the gear adjustment bolts. 1.2.4 Remove the bearings and bearing housings, and inspect the oil seals and bearings. 1.2.5 Remove the sealing components and inspect the labyrinth sleeve, moving ring, stationary ring, O-rings, and other sealing parts. 1.2.6 Remove the wall panels and inspect the wall panels and rotor. 1.3 Quality Standards 1.3.1 Airframe 1.3.1.1 The airframe shall be free from damage and cracks. 1.3.1.2 The levelness of the machine body installation is 0.04 mm/m. 1.3.2 Rotor 1.3.2.1 The rotor surface shall be free from defects such as sand holes, pores, and cracks. 1.3.2.2 The circular runout of the rotor end face shall not exceed 0.05 mm. 1.3.2.3 The rotor is subjected to static balance or balance verification. 1.3.3 Gaps between rotors, as well as gaps between the rotors and the casing and wall panels. 1.3.4 Shaft. 1.3.4.1 The surface of the shaft should be smooth, free from scratches and cracks. 1.3.4.2 The cylindricity of the shaft journal shall not be greater than half of the shaft diameter tolerance. 1.3.4.3 The coaxiality of the shaft is 0.03 mm/m. 1.3.5 Couplings or V-belts 1.3.5.1 Couplings a. The alignment of the coupling should have a radial runout error of 0.06 mm, and an end-face runout error of 0.05 mm. b. The axial clearance during coupler installation shall comply with Table 4. 1.3.5.2 V-belt a. The belt tension W should be moderate or as specified in Table 5 ； A force W is applied at the center of L in a direction perpendicular to the belt, such that the deflection at this point reaches δ = 0.016L; the value of the force W should then correspond to that in Table 5. Table 4 Axial clearance during coupling installation, in mm. b. The deviation of the belt groove center shall not exceed 0.05 mm/100 mm. 1.3.6 Bearings 1.3.6.1 Rolling shafts a. The rolling elements and the raceway surfaces should be free of scratches, pitting, or rust, and the retainers should be free of deformation or damage. b. The inner ring of the rolling bearing and the shaft are fitted using the H7/k6 fit, while the bearing housing and the outer ring of the bearing are fitted using the H7/h6 fit. c. The rolling bearing must be mounted firmly against the shaft shoulder or a shoulder pad. d. The temperature of the bearings during hot installation shall not exceed 120°C; direct flame heating is strictly prohibited. 1.3.6.2 Sliding bearings: a. After scraping and lapping, the imprint on the bearing surface should be uniform, with generally no less than 2–3 points per cm2; the contact angle is usually between 60–90°. b. The bearing top clearance is shown in Table 6. c. The side clearance is 1/2 of the top clearance. d. The bearing liner and the bearing backing should make good contact, with the contact area generally being over 60%. 1.3.7 Sealing devices 1.3.7.1 The interference fit between the V-ring and the shaft is generally 0.1 mm. 1.3.7.2 The parallelism at both ends of the labyrinth seal sleeve shall not exceed 0.01 mm, and the axial clearance between the seal ring seat and the sleeve is generally 0.2 to 0.5 mm. 1.3.7.3 After the mechanical seal is assembled, the radial runout of the shaft’s centerline at the moving seal ring shall not exceed 0.06 mm. 1.3.8 Synchronous gears 1.3.8.1 After the gears are fixed with keys, their radial displacement shall not exceed 0.02 mm. 1.3.8.2 The tooth surface contact shall be not less than 50% along the tooth height and not less than 70% along the tooth width. 1.3.8.3 The tip clearance shall be 0.2–0.3m (where m is the module), and the side clearance shall comply with the requirements specified in Table 7. 2. Maintenance and Fault Handling 1.1 Routine Maintenance 2.1.1 Check the casing temperature and keep records. 2.1.2 Regularly check the bearing temperature and keep records. 2.1.3 Periodically check for friction or vibration. 2.1.4 Regularly check the lubricant level and whether the oil has emulsified, etc. 2.1.5 Regularly check the pressure difference of the suction inlet filter. 2.1.6 Regularly check the self-starting function of the standby oil pump motor for high-power fans, as well as the pressure difference across the oil filter. 2.1.7 Use mechanical seals and pressure lubrication, and regularly check the oil pressure and oil temperature. 2.1.8 Regularly check the suction and exhaust pressures. 2.1.9 Periodically check the motor load. 2.1.10 Regularly check whether the cooling water is unobstructed. 2.1.11 Conduct regular inspections and keep records. 2.2 Common Faults and Solutions (see Table 8)