1. Preparation Before Cleaning
: Cut off the power supply of the mixer and hang a "No Operation During Cleaning" sign to prevent accidental startup.
: Open the inspection door or manhole of the mixing drum to observe the location, thickness, and hardness of accumulated materials (e.g., loose powder, hardened blocks, or sticky residues).
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Cleaning tools: Shovels, chisels, wire brushes, high-pressure water guns (with adjustable pressure), and soft brushes (for delicate parts like seals).
Cleaning agents: Depending on the material (e.g., concrete remover for cement-based residues, neutral detergents for general dirt; avoid corrosive agents that damage the drum).
Safety equipment: Gloves, goggles, dust masks, and anti-slip shoes.
Auxiliary items: Buckets, rags, and a waste container for collected residues.
2. Basic Cleaning Steps
The cleaning process varies slightly based on the type of accumulated material, but the core logic is "remove loose materials first, then tackle hardened/sticky residues."
A. Removing Loose Accumulated Materials
For powdery or slightly agglomerated materials (e.g., unused cement, fly ash):
Use a shovel or brush to sweep loose materials into a collection container to avoid dust diffusion.
If there's a discharge port, open it and let the loose materials fall out naturally, then clean the remaining powder with a wire brush.
B. Cleaning Sticky or Semi-Hardened Residues
For materials that are sticky (e.g., mortar) or partially hardened but not firmly bonded:
Pre-softening: Spray water or a diluted cleaning agent (e.g., concrete remover) on the residues and let it soak for 10–30 minutes (depending on hardness) to soften the material.
: Use a wire brush or soft shovel to scrape off the softened residues. Focus on corners, shaft ends, and the gaps between mixing blades and the drum wall-these are high-risk areas for accumulation.
High-Pressure Washing: Use a high-pressure water gun (pressure 150–300 bar) to rinse the drum wall, blades, and shafts. Adjust the water pressure to avoid damaging the drum's inner coating (e.g., wear-resistant liners).
C. Removing Hardened or Thick Accumulations
For severely hardened materials (e.g., fully set concrete blocks) that cannot be softened by water:
: Use a chisel and hammer to gently chip off the hardened blocks. Avoid violent impacts to prevent damage to the drum wall, blades, or shaft bearings. For large blocks, split them into smaller pieces first.
: For heat-resistant materials, use hot water (60–80℃) to soak the residues to accelerate softening (not suitable for materials sensitive to high temperatures).
Post-Cleaning Rinse: After removing large chunks, use a high-pressure water gun to clean remaining debris and ensure no small residues are left in gaps.
3. Key Areas to Focus On
Twin-shaft mixers have critical areas prone to accumulation; these require thorough cleaning:
: Residues often stick to the blade surfaces and shaft connections. Use a wire brush to scrub, and a high-pressure water gun to flush gaps.
: Hardened materials may adhere to the inner wall, especially at the bottom and near the discharge port. Use a chisel (with light force) to remove them, then rinse.
: Blockages here can affect material discharge. Use a shovel or brush to clear residues, and check if the valve moves smoothly after cleaning.
: Avoid direct high-pressure water or hard tools on seals (e.g., rubber gaskets) to prevent damage. Wipe them gently with a damp cloth.
4. Post-Cleaning Inspection and Maintenance
: Re-inspect the drum, blades, and gaps to confirm no accumulated materials remain.
: If the mixer won't be used immediately, run it empty for 5–10 minutes to dry moisture (prevent rust or mold).
: Apply lubricant to bearings, shafts, and valves as per the equipment manual to reduce friction.
: Restore power, run the mixer empty for a short time, and listen for abnormal noises (indicating possible residual debris or component damage).
5. Preventive Measures to Reduce Future Accumulation
To minimize re-accumulation, adopt these daily practices:
: After each mixing cycle, rinse the drum with a high-pressure water gun while the residues are still soft (especially for cement-based materials).
: Check the mixing drum weekly for early signs of accumulation; address small residues before they harden.
: If materials are prone to sticking, optimize the water-material ratio or mixing time (consult the material supplier if needed).
Use Anti-Stick Coatings: For long-term use, apply food-grade or industrial anti-stick coatings (compatible with the material) to the drum inner wall (follow manufacturer guidelines).