**Guidelines for gap adjustment of Roots blower**
The clearance adjustment of Roots blower directly affects its operating efficiency, noise, lifespan, and sealing performance. Mainly involving the clearance between rotors, the clearance between rotors and casings, and the clearance between rotors and end caps. The following are detailed gap standards, measurement methods, and adjustment steps.
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**1. Main gap types of Roots blower**
|Gap Type * * | * * Standard Value (mm) * * | * * Impact * * | * * Adjustment Method * *|
|----------------------|----------------|--------------------------|-------------------------|
|* * Interrotor clearance * * | 0.10~0.25 | Excessive → Increased leakage and decreased efficiency< Br>Too small → Friction heating, jamming | Adjust the meshing position of the synchronous gear|
|* * Gap between rotor and casing * * | 0.15~0.35 | Excessive → Internal leakage, reduced air volume< Too small → Scratching and wear | Grinding the rotor or inner wall of the casing|
|* * Gap between rotor and end cover * * | 0.10~0.20 | Excessive → Axial displacement, seal failure< Br>Too small → End face friction | Adjust the thickness of the end cap gasket|
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**2. Gap measurement method**
**(1) Tool preparation**
-* * feeler gauge * * (0.02~1.00mm)
-* * dial gauge * * (measuring axial movement)
-* * Micrometer * * (measuring rotor diameter)
**(2) Measurement steps**
**① Measurement of clearance between rotors**
1. Manually rotate the two rotors to a horizontal symmetrical position (with peaks facing each other).
2. Use a feeler gauge to measure the * * gap * * between the rotor peaks (take the average of at least 3 positions).
**② Measurement of clearance between rotor and casing**
1. Fix the dial gauge with the probe against the outer edge of the rotor.
2. Manually rotate the rotor and record the radial runout value (should be ≤ 0.05mm).
3. Use a feeler gauge to measure the gap between the rotor and the inner wall of the casing (4 points up, down, left, right).
**③ Measurement of clearance between rotor and end cover**
1. Install a dial gauge, push the rotor axially, and measure the axial displacement (should be ≤ 0.10mm).
2. Measure the gap between the rotor end face and the end cover with a feeler gauge.
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**3. Gap adjustment method**
**(1) Adjustment of clearance between rotors**
-* * Steps * *:
1. Loosen the positioning pin or locking nut of the synchronous gear.
2. Slightly rotate the gear to change the rotor phase (adjust the meshing position).
3. Re measure the gap, tighten the gear, and perform a re inspection.
-* * Key Points * *:
-After adjustment, it is necessary to ensure that the two rotors rotate synchronously without interference.
-Use a dial gauge to monitor the gear backlash (usually 0.03~0.05mm).
**(2) Adjustment of clearance between rotor and casing**
-* * Method * *:
-If the gap is too large, replace the rotor or repair the inner wall of the casing (professional machining is required).
-If the gap is too small, lightly polish the outer edge of the rotor to maintain dynamic balance.
**(3) Adjustment of clearance between rotor and end cover**
-* * Steps * *:
1. Remove the end cap and measure the thickness of the existing gasket.
2. Increase or decrease shims (adjustable gap of approximately 0.03mm per 0.05mm shim).
3. Reinstall the end cap and manually turn the disc to confirm that there is no friction.
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**4. Reference values for clearances of different models**
|Wind turbine model * * | * * rotor gap (mm) * * | * * casing gap (mm) * * | * * end cap gap (mm) * *|
|--------------------|---------------------|-------------------|-------------------|
|Small (≤ 15kW) | 0.10~0.15 | 0.15~0.25 | 0.08~0.15|
|Medium (15~75kW) | 0.15~0.20 | 0.20~0.30 | 0.10~0.18|
|Large (>75kW) | 0.20~0.25 | 0.25~0.35 | 0.12~0.20|
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**5. The impact and handling of abnormal gaps**
|* * Problem Phenomenon * * | * * Possible Causes * * | * * Solution * *|
|--------------------|--------------------|--------------------------|
|Insufficient air volume | Excessive clearance between rotors/casings | Adjust or replace worn parts|
|Abnormal noise/vibration | Friction caused by too small gap | Adjust gap again and check alignment|
|Frequent bearing damage | Excessive axial clearance | Adjust end cap gasket|
|Excessive temperature | Friction heat generated by rotor | Correct clearance, check lubrication|
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**6. Maintenance suggestions**
-* * Regular inspection * *: Measure the gap every 2000 hours of operation.
-Lubrication Management: Use qualified gear oil (ISO VG 220) to avoid oil contamination affecting clearances.
-* * Fault Warning * *: If there is an increase in current fluctuations or abnormal noise, priority should be given to checking the gap.
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**Summary**
The gap adjustment of Roots blower is the key to ensuring operation, which needs to be accurately measured with * * plug gauge and dial gauge, and follow the principle of * * "better big than small" * * (to avoid friction). After adjustment, it is necessary to conduct a no-load test run to confirm that there is no abnormal vibration or temperature rise before putting it into load operation.
