How should the cleaning path and intensity be designed in the cleaning process of a liquid filling machine to ensure that every corner of the bottle is thoroughly cleaned without damaging it?
Publish Time: 2026-02-05
In a fully automatic rotary three-in-one liquid filling machine, the cleaning process is the first line of defense for ensuring food safety and product quality. This is especially true for large-capacity PET bottles (5-20 liters)—containers commonly used for filling drinking water, cooking oil, juice, or chemical liquids—whose height and diameter are relatively small, and whose bottoms are prone to accumulating dirt. If cleaning is not thorough, residual microorganisms or foreign matter will directly contaminate the contents. However, while PET material is lightweight and transparent, it is relatively soft and has limited pressure resistance. Excessive rinsing force or improper spray angles can easily cause bottle deformation or even breakage. Therefore, modern filling machines achieve a delicate balance between "cleaning" and "bottle protection" through multi-dimensional spray path planning, intelligent pressure control, and contoured nozzle design.
1. 360° Full Coverage Spray Path: The Key to Thorough Cleaning
To address the complex internal structure of large-capacity PET bottles, the cleaning station employs multi-axis rotating nozzles or fixed multi-hole spray rings. The mainstream solution involves inserting a retractable, self-rotating high-pressure spray bar into the bottle opening. Its tip integrates multiple micro-nozzles distributed in a spiral pattern at different angles. Once inside the bottle, the spray bar moves up and down while rotating at high speed, creating an umbrella-shaped + spiral composite flow field that ensures the water reaches all areas, including the bottle shoulder, bottle wall, bottom center, and edges. Some high-end models are also equipped with a dual-spray bar system: the main spray bar handles the main cleaning, while the secondary spray bar targets the bottle bottom grooves, achieving true "zero blind spots."
2. Graded Pressure Control: A Cleaning Strategy Combining Strength and Gentleness
More powerful cleaning is not always better. The equipment typically features a multi-stage pressure regulation program: an initial low-to-medium pressure pre-rinse removes floating dust and loose dirt; this is followed by a high-pressure main wash to break down stubborn deposits; and finally, a low-pressure rinse removes residual water droplets. Crucially, the pressure value is automatically matched to the bottle type—the PLC calls upon the parameter library corresponding to 5L, 10L, or 20L bottles to prevent smaller bottles from experiencing excessive impact. Simultaneously, the spray boom's rising/falling speed and rotation frequency are synchronized to ensure uniform force per unit area, preventing stress cracking of the PET material due to localized sustained high pressure.
3. Contouring Nozzles and Cleaning Media Optimization
Nozzle design directly affects the water flow pattern. High-quality cleaning systems use Venturi effect nozzles or fan-shaped atomizing nozzles to transform the water flow into a fine water curtain or high-speed jet, achieving high impact efficiency at lower pressures. Furthermore, the cleaning media is optimized: clean water with a filtration accuracy ≤5μm is used to avoid secondary contamination; some food or pharmaceutical applications also incorporate ozone for online sterilization, improving cleanliness without leaving chemical residues. Water temperature is also adjustable; warm water helps emulsify and remove grease stains, but the upper limit must be strictly controlled to prevent the PET from softening and deforming.
4. Bottle Positioning and Flexible Clamping: Preventing Mechanical Damage During Cleaning
Driven by a rotating star wheel, the PET bottle needs to remain stable during high-speed operation. The cleaning station uses a pneumatic flexible clamping device that only clamps the firm part below the bottle neck thread, avoiding compression of the bottle body. Simultaneously, a follow-up bottle support plate at the bottom supports the bottle bottom synchronously with the rise and fall of the spray bar, counteracting the backlash of the water flow. The entire process is free of hard collisions; even 20L large bottles filled with water can be cleaned smoothly, preventing scratches or tipping caused by shaking.
The cleaning process of the liquid filling machine is a precise "dance of water"—the water flow path is as precise as a scalpel, the pressure control as gentle as breathing; every drop of water carries a cleaning mission, yet is treated with utmost respect for the fragile PET bottle. It is this pursuit of perfection in details that allows the fully automatic three-in-one filling machine to maintain food safety at high speeds while delivering clear, pure, and safe products to consumers.
