1. Manual Cleaning Method

For parallel ducts larger than 40 cm square, technicians can manually enter and clean them. This method is labor-intensive and requires proper ventilation and low-voltage (36V) lighting.  

2. Disassembly Cleaning Method 

Used for ducts smaller than 40 cm square where manual entry is impossible. Technicians disassemble sections of the duct at intervals and clean both directions. This method is highly effective but technically challenging and costly.  

3. Hole-Opening Cleaning Method 

Applied to ducts that are neither accessible nor easy to disassemble. Technicians use specialized non-sparking tools to open holes on one or more sides of the duct. The size, spacing, and number of holes depend on the situation. After cleaning, the holes are sealed.  

4. Machine-Assisted Cleaning Method

Suitable for ducts with minimal grease buildup and short cleaning cycles. A cleaning agent is sprayed inside to soften grease, followed by robotic scrubbing (for horizontal ducts) or rotary nozzle cleaning with a multifunctional machine (for vertical ducts). This method works for vertical ducts (30 cm square) that are inaccessible or hard to disassemble. Such ducts tend to accumulate grease quickly, requiring shorter cleaning intervals.  

5. Descending Cleaning Method 

Primarily used for vertical ducts larger than 50 cm square. Technicians remove the upper and lower sections of the duct, secure a high-altitude safety rope, and clean from top to bottom using safety harnesses. This method is high-risk, technically complex, and expensive but highly effective. Vertical ducts generally require annual cleaning due to slower grease buildup.  

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