I. Based on raw material type: Establish differentiated cleaning standards. The impurity characteristics of different raw materials directly affect the deposition rate, which is the starting point for determining the cleaning frequency.
1. High-protein raw materials (e.g., potatoes, sweet potatoes): High protein content (>1.5% dry basis) easily forms gelatinous deposits on the inner wall of the hydrocyclone tube. It is recommended to perform alkaline washing every 24 hours and CIP (Clean-In-Place) cycle cleaning every 48 hours.
2. Low-protein raw materials (e.g., corn, wheat): Impurities are mainly fiber and fine sand, which deposit more slowly. The alkaline washing cycle can be extended to once every 48–72 hours, but a rinse with clean water is still required after each shift.
3. Viscous polysaccharide raw materials (e.g., cassava, kudzu root): Containing a large amount of soluble polysaccharides, they easily form a sticky film adhering to the tube wall. It is recommended to perform alkaline washing + hot water rinsing daily, and add biological enzymes to assist decomposition if necessary.
✅ Tip: When changing raw material batches (e.g., switching from corn to sweet potatoes), deep cleaning should be performed immediately to prevent cross-contamination.
II. Triggering Based on Operating Parameters: Establish a Real-Time Response Mechanism Cleaning should be initiated immediately upon the occurrence of any of the following abnormal signals, regardless of the basic cycle:
1. Feed pressure increases by ≥10% and lasts for more than 15 minutes. This indicates increased system resistance, possibly due to scaling or localized blockage.
2. Overflow becomes turbid or contains visible starch particles. This indicates separation failure, most likely caused by protein deposition leading to turbulent flow.
3. Final stage starch-milk protein content >0.55% (dry basis). Laboratory testing or near-infrared rapid analysis reveals excessive levels, indicating insufficient washing.
4. Underflow changes from "rope-like" to columnar or dripping. This is an early visual signal of blockage; combined with pressure changes, cleaning needs can be quickly determined.
✅ Technical Recommendation: Install a differential pressure transmitter and an online turbidity meter to achieve automatic cleaning triggering and improve response efficiency.
III. Ensuring Stability Through Maintenance Cycles: Implementing Mandatory Operational Steps
Regardless of operating status, the following steps must be performed to ensure long-term equipment stability:
Daily Cleaning: After each shift, rinse with clean water for 15 minutes + circulate a 2% NaOH solution (60–65℃) for 1 hour.
In-Depth Inspection: After 500 hours of cumulative operation, disassemble the hydrocyclone tube, soak it in 5% NaOH for 2 hours, clean it with a nylon brush and high-pressure water gun, and inspect the wear of the underflow orifice.
Seal Replacement: Replace O-rings and gaskets every 2000 hours or when leaks are detected to prevent external impurities from entering.
Long-Term Shutdown Protection: Keep the system moist with water if shutdown exceeds 24 hours to prevent the nylon hydrocyclone tube from drying and shrinking.
✅ Key Reminder: Wear on the underflow orifice of the hydrocyclone tube will increase its diameter, disrupting the centrifugal field distribution. It is recommended to use a standard plug for periodic testing; replace the tube if the diameter exceeds the standard.
IV. Meeting Wuxi Local Compliance Requirements: Strengthening Risk Management
According to the "Food Safety Risk Management List (Starch and Starch Product Production)" and the Wuxi Municipal 2025 Cleaning Agent Regulatory Rules:
A written cleaning and disinfection SOP must be established, clearly defining the frequency, method, and responsible person.
Regularly verify the cleaning effect (e.g., turbidity of rinsing water, microbial testing).
Retain cleaning records for at least 2 years for regulatory verification.
It is recommended to use food-grade NaOH or bio-enzyme cleaning agents to avoid the risk of chemical residues.
