Aseptic cold filling machine is a core equipment in the modern beverage industry, especially in the production of high-end fruit juice, tea drinks, and functional beverages. The core principle is to fill sterilized and cooled materials into sterilized packaging containers in an absolutely sterile environment and immediately seal them, thereby achieving commercial sterility and long-term room temperature storage of the product.
The following is a detailed step-by-step analysis of its working principle:
Core objective:
Filling at room temperature to preserve the flavor, color, vitamins, and nutritional components of food materials (especially heat sensitive products) to the greatest extent possible, while achieving the same sterile effect and long shelf life as hot filling (high-temperature filling).
Detailed explanation of working principle step by step
Phase 1: Material sterilization and cooling
Sterilization method: UHT (Ultra High Temperature Instant Sterilization) technology is used. The material (if juice) is rapidly heated to extremely high temperatures (e.g. 135-150 ° C) in a closed pipeline, but only for a very short period of time (a few seconds).
Key step: After sterilization, immediately cool to room temperature (usually below 25 ° C) through a heat exchanger. This' rapid cooling 'step is crucial as it minimizes the loss of thermosensitive components caused by continuous heating.
Status: At this point, the material is sterile and must be transported in a closed sterile pipeline in all subsequent processes to prevent further contamination.
Phase 2: Sterilization and treatment of packaging containers
This is the key difference between aseptic cold filling and regular filling. The packaging container (usually PET plastic bottle) and bottle cap are sterilized independently.
Bottle sterilization:
Mainstream technology: Use hydrogen peroxide (H ₂ O ₂) solution or its vapor, combined with sterile air/hot air for sterilization and drying.
Process: The bottle is inverted, and H ₂ O ₂ mist spray or steam is injected into the bottle to ensure complete infiltration of the inner wall for sterilization. Subsequently, sterile hot air passing through a high-efficiency particulate air (HEPA) filter is introduced to blow away and decompose the residual H ₂ O ₂ in the bottle, ensuring that the bottle is dry and sterile.
Bottle cap sterilization: Typically, sterilization is carried out through methods such as ultraviolet irradiation, steam or hydrogen peroxide soaking.
Aseptic transportation: The sterilized bottles and caps are transported to the filling area through a sealed sterile channel or a sterile air environment maintained at positive pressure.
Phase Three: Establishment and Maintenance of Aseptic Environment
The entire filling process takes place in a continuously controlled 'sterile core area'.
Physical isolation: Key areas of the filling machine, such as the filling head and capping head, are sealed in a sterile chamber.
Air purification: Continuously introduce sterile air filtered by HEPA high-efficiency filters into the sterile chamber to maintain a cleanliness level of ISO 5 (Class 100) or higher.
Positive pressure protection: The air pressure inside the sterile chamber is slightly higher than the outside, ensuring that any possible contaminated air can only flow outward and cannot enter the sterile area.
Stage 4: Filling and Sealing
Aseptic filling: The cooled sterile material is injected into sterile bottles through sterile tubing and filling valves, under precise control of gravity, pressure, or volume pumps. The design of the filling valve can prevent dripping and aerosol generation, and avoid cross contamination.
Instant sealing: After filling, the bottle is immediately transported to the sealing area and sealed instantly with sterilized bottle caps (such as screwing or capping). The sealing process is also completed under sterile protection.