Roots blower repair guide
Roots blower, as a volumetric gas conveying equipment, is widely used in environmental protection, chemical industry, cement and other fields. Its common faults are often related to component wear, clearance misalignment, and poor lubrication. The following are repair methods and precautions for typical faults:
1、 Core fault types and repair methods
1. Friction between impeller and impeller/casing
Reason: impeller fouling, gear wear, and excessive bearing clearance.
Repair:
Impeller dirt, check the gear backlash (>0.18mm needs to be replaced).
Adjust the gear clearance to 0.10-0.18mm, ensuring that the taper fitting contact area is ≥ 75.
Replace the worn bearing and control the clearance within 0.05-0.10mm.
2. High temperature
Reason: Excessive oil volume/viscosity, clogged filter, excessive pressure.
Repair:
Lower the oil level to the centerline of the window and replace the ISO VG 68 anti-wear hydraulic oil.
Clean the filter and replace the filter element when the pressure difference exceeds 500Pa.
Reduce the system back pressure to within 1.1 times the rated value.
3. Insufficient traffic
Reason: Import filter blockage, impeller wear, belt slippage.
Repair:
Clean the inlet filter screen and repair the impeller clearance (≤ 0.6mm).
Tighten the belt, with a tension drop of 10-15mm, and replace it if necessary.
Adjust the import pressure to the specified range.
4. Abnormal vibration and noise
Reason: Excessive bearing clearance, excessive gear backlash, and impeller imbalance.
Repair:
Replace the bearing or bearing seat, and tighten the anchor bolts.
Reinstall the gear to ensure a side clearance of 0.10-0.18mm.
Clean the impeller and casing, calibrate the dynamic balance.
2、 Key component repair standards
Component repair standards
Gear clearance side clearance 0.10-0.18mm, contact area ≥ 75; The blade clearance is ≥ 0.15mm, and the blade clearance is ≥ 0.30mm.
The total clearance of the impeller is 0.2-0.4mm, with a single-sided axial clearance of 0.12-0.18mm (front wall panel) and 0.63-0.69mm (rear wall panel).
Replace high-precision bearings such as SKF and NSK with a clearance of 0.05-0.10mm.
Press the middle of the belt with your thumb to reduce the tension by 10-15mm.
3、 Professional repair process
1. Disassembly and Inspection:
Mark the disassembly sequence to avoid damaging the mating surface.
After cleaning the components, check for wear, cracks, and deformation.
2. Component repair/replacement:
Minor wear can be repaired by welding and machining.
Severe wear or deformation requires replacement with new parts (such as side cover plates and bearing seats).
3. Gap adjustment:
Use a feeler gauge and lead wire method to check the gap.
Adjust the clearance between the split and combined blades to the standard value to ensure that the impeller is collision free.
4. Assembly and testing:
Apply lubricating grease and assemble in the reverse order of disassembly.
Run for 2 hours and check for temperature, vibration, and noise.
4、 Preventive maintenance recommendations
1. Regular inspection:
Record vibration value ≤ 4.5mm/s, oil temperature ≤ 75 ℃, and current ≤ rated value for each shift.
Check the quality of the gearbox oil weekly and replace it when the moisture content is greater than 0.1.
2. Lubrication management:
Keep the oil level at the centerline of the window and clean the air filter every 2000 hours.
Replace the lubricating oil every 5000 hours and use anti-wear hydraulic oil.
3. Environmental control:
Maintain good ventilation and reduce inlet temperature.
Avoid media containing dust and water vapor, and prevent the gap between the shell and rotor from decreasing.
5、 Typical Case Analysis
1. Fault phenomenon: The noise level of the Roots blower in a certain sewage treatment plant reaches 95dB (A), with a vibration speed of 8mm/s.
2. Diagnosis: Gear backlash is 0.25mm (exceeding 40%), and the inner ring of the bearing is worn.
3. Solution: Replace the gear set (with side clearance adjusted to 0.12mm) and SKF 6311 bearings to reduce vibration to 3mm/s and noise to 82dB (A).
6、 Precautions
1. Operation:
The fan that has just been stopped should be disassembled after cooling to avoid.
Use a torque wrench to tighten the bolts according to specifications.
2. Professional tools:
Equipped with specialized tools such as feeler gauges, lead wires, and laser alignment instruments.
The adjustment of gear clearance requires the use of red lead powder to check the meshing contact area.
3. Spare parts management:
Reserve commonly used spare parts (such as bearings, gears, oil seals).
Regularly check the expiration date of spare parts and avoid using expired lubricating oil.
Through systematic maintenance and precise adjustment, the lifespan of Roots blowers can be significantly extended (usually up to 8-10 years), reducing unplanned downtime rates. In case of complex faults, it is recommended to contact professional technical personnel for handling.
