### Purpose of Aseptic Cold Filling Line
The purpose of an aseptic cold filling line is to produce safe, uncontaminated final products at specific production speeds.
To achieve this, the following must be ensured:
- The containers, caps, and equipment must be free from contamination.
- Any factors that could potentially contaminate the final product-both microbiologically and chemically-must be eliminated.
This objective is achieved through the following operations:
- Provide and maintain a sterile environment for the aseptic filling process.
- Sterilize the surfaces of containers and caps that come into contact with the product.
- Fill sterile containers with sterile product.
- Ensure container sealing integrity.
The following features ensure the realization of these functions:
- The entire sterilization/rinsing/filling/capping area is enclosed within a microbial isolation chamber, which provides positive pressure and sterile air.
- Bottle and cap sterility is achieved through online sterilization and sterile water rinsing.
- All piping that comes into contact with the product and related fluids is cleaned via automatic CIP (Clean-in-Place) programs and sterilized via SIP (Sterilize-in-Place) programs.
- All critical operating parameters are monitored in real time; however, the concentration of the sterilizing solution is manually tested and controlled.
In addition to ensuring control over contamination, the microbial isolation chamber also allows operators to access the internal system without compromising the system's sterility. This operation is made possible through gloves installed at key points inside the system.
Therefore, to monitor the system's sterility, it is possible to replace consumable parts or perform microbiological sampling without compromising the sterility of the entire line or stopping production.
Furthermore, due to full automation of the operation, potential contamination caused by incorrect use of the production line can be avoided.
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## 1. System Overview
To ensure the sterility of the entire line, the components and additional processes of the system are described separately below.
### A. Bottles
Empty bottles are transported to the main machine area via a sterile air conveyor belt. In the main area, the bottles pass through two adjacent rotating machines: the first group (two sterilizers) performs sterilization on the bottles, and the second group rinses the bottles before delivering them to the filling and capping areas.
### B. Caps
Caps delivered to the production line undergo chemical sterilization.
The caps are fed into a hopper, then conveyed upward into the cap sterilization area. They are sterilized, rinsed, and dried under controlled conditions before being directly sent to the capping machine.
### C. Product
The product undergoes thermal sterilization and is cooled before being sent to the filling area.
a) High-pressure nitrogen or sterile air transports the product into the filler.
b) The entire product pipeline is cleaned and sterilized through regular CIP/SIP cycles.
### D. Sterile Environment
Bottles and caps are introduced into a microbial isolation chamber: the controlled sterile environment is achieved through chemical sterilization treatment. The isolation chamber is sealed off from the outside and continuously maintained under positive pressure using sterile air, preventing the entry of external contaminants. Isolation chambers installed at workstations serve two purposes: allowing access for maintenance without contaminating the sterile environment and protecting operators from exposure to chemicals.
### E. Process Fluids Used
The correct operation of the system requires high-quality fluids. Therefore, all fluids are treated to prevent contamination of the production line. Based on this requirement, they undergo the following treatments:
- **Sterile Air**: Treated through a pair of sterile-grade filters in series to maximize safety (if one filter fails, the other still ensures sterility).
- **Nitrogen (if used)**: Treated through sterile filters (similar to compressed air).
- **Steam**: Steam passes through filters to ensure its purity and protect steam-sterilized machines and components (air filters, nitrogen filters, fillers).
- **Water**: Water is treated at ultra-high temperatures to produce sterile water used in production and rinse steps during startup cycles.
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## 2. Description of Individual Machines on the Production Line
The production line consists of the following individual machines:
- Sterilizer and Rinsing Machine
- Filler
- Cap Sterilizer
- Bag Sterilizer or Tunnel (if applicable)
- Capper
- Peracetic Acid Preparation Unit – Unidox
- Automatic Titration Unit (if applicable)
- Sterile Filtration Unit (Uniflux) and Foam Unit
- CIP Unit – Uniclean
- Sterile Water Preparation Unit – Unitherm H
- Liquid Nitrogen Metering Unit
- Microbial Isolation Chamber Ventilation and Pressurization System
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### 2.1 Sterilization and Rinsing
In the aseptic cold filling line, bottles must reach a sterile state before filling. To achieve this, the bottles pass through three adjacent rotating machines: first sterilized with peracetic acid solution, then rinsed with sterile water.
In the two sterilizers, the sterilizing solution is sprayed onto both the internal and external surfaces of the bottles via dedicated nozzles to cover all bottle surfaces. After sterilization, the bottles enter the rinser for internal rinsing.
All three rotating machines are equipped with nozzle blockage sensors (nozzle detection units) to detect proper spray performance of the internal processing/rinsing nozzles.
Peracetic acid solution can be recycled and reused after retesting confirms it meets requirements. If required, sterile water may also be recycled after removing hydrogen peroxide.
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### 2.2 Filler
The filler's function is to accurately fill the rinsed sterile bottles with the correct volume of product while ensuring that neither the bottles nor the product are contaminated during the filling process.
A sterile buffer tank uses sterile air or nitrogen to maintain positive pressure, ensuring sterility and protecting the product from any form of contamination, while delivering the product to the rotating disc of the filler.
Photoelectric sensors detect the presence of bottles to control the opening and closing of the nozzles; no bottle means no filling.
The product is precisely metered as it fills the bottle. The shape of the nozzle minimizes turbulence during filling. The filled bottles are then conveyed to the capper for capping.
The filler includes all necessary functions for production and startup cycles (CIP/SIP cycles) to ensure, maintain, and store sterility.
Note: There are two types of aseptic fillers-one specifically for non-carbonated beverages called FILLSTAR FX, and another, FILLSTAR CX, which can handle both carbonated and non-carbonated beverages.
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### 2.3 Cap Sterilizer
The purpose of this unit is to sterilize, rinse, and deliver the caps to the filling-capping area.
Caps are oriented by a cap feeder and enter the cap sterilization unit. They are sterilized with peracetic acid solution at a certain temperature, rinsed with sterile water, and dried with sterile air before entering the cap pickup and placement device.
To minimize losses, the peracetic acid solution used in the rinse process is recovered.
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### 2.4 Bag Sterilizer or Tunnel (if applicable)
#### Bag Sterilizer
The purpose of this unit is to provide sterilization for caps that cannot be chemically sterilized but must instead be irradiated. The sterilized caps are conveyed via a sterile conveyor belt into the cap orienter.
The operator places pre-sterilized cap bags on hooks inside the bag sterilizer, closes the system, and initiates the sterilization cycle. Upon completion of the cycle, the operator can discharge the caps into the hopper.
From there, the caps are continuously fed to the capper in a sterile environment.
#### Bag Tunnel
The purpose of this unit is to provide sterilization for caps that cannot be chemically sterilized but must instead be irradiated. The sterilized caps are conveyed via a sterile conveyor belt into the cap orienter.
The operator places pre-sterilized cap bags onto the conveyor belt passing through the tunnel. The bags first pass through a PAA solution, then are dried. Once the caps reach the end of the tunnel, the operator must open the machine and place the caps into the hopper.
From here, the caps are continuously fed to the capper in a sterile environment.
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### 2.5 Capper
Mounted on the same frame as the filler, the capper applies and tightens sterile caps.
The capping turntable is equipped with a "pick-and-place" cap system and a "no bottle, no cap" supply system.
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### 2.6 Peracetic Acid Preparation Unit – Unidox
The Unidox system prepares and heats peracetic acid solution to meet the required concentration, temperature, pressure, and flow rate for sterilization during production (for bottles and caps) and startup cycles (equipment surface sterilization inside the microbial isolation chamber).
Concentrated peracetic acid (PAA) is added to a batch tank above the storage tank. According to machine-set concentrations, the system adds measured amounts of concentrated sterilizing liquid and water to achieve the desired use concentration. Once each batch is prepared, the working solution is transferred to the storage tank.
When the liquid level in the storage tank reaches the preset point, the system heats the sterilizing solution to the required temperature, initially requiring manual titration for concentration verification.
**PAA Recirculation Process**: The sterilizing liquid flows back to a recovery tank near the sterilizer and is then recirculated through a centrifugal pump to the Unidox system. The recovery system is used during both production and external sterilization phases when peracetic acid is in use.
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### 2.7 Automatic Titration Unit (if applicable)
The system can continuously and automatically detect the concentration of peracetic acid solution through an automatic titrator.
The automatic titrator contains chemical reagents to titrate the peracetic acid concentration. At preset intervals, the titrator draws samples from the circulation system for analysis to monitor both hydrogen peroxide and peracetic acid concentrations, then feeds the values back to Unidox, which may require recalculations.
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### 2.8 Sterile Filtration Unit (Uniflux) and Foam Unit (Unifoam)
All fluids used in the system must be filtered to meet microbiological requirements. This unit includes:
- Steam filters,
- Pre-filters and final air filters,
- Dual nitrogen filters (if applicable),
- Filter systems sterilized with steam.
This system is used in fully automatic mode to clean the external surfaces of the filler and capper during the external cleaning phase of the startup cycle.
Foam is created by adding the appropriate amount of foaming agent to water, forming foam that is sprayed under high pressure to ensure chemical effectiveness during cleaning. The foam is selected based on its ability to adhere to machine surfaces and remove product residue within minimal contact time.
The foam generator operates in automatic mode, with rotary spray heads installed in the sterile zone, enabling automated cleaning of all external surfaces without manual intervention.
External automatic cleaning includes two separate foam/rinse cycles executed before and after installing dummy bottles.
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### 2.9 CIP Unit – Uniclean
The purpose of this unit is to perform automatic rinse cycles for the sterile tank and filler.
The main components of this unit are:
- Two tanks for holding cleaning solutions: NaOH and HNO3
- A tubular heat exchanger for heating the cleaning solution.
The cleaning cycle inside the filler is part of the SANITATION cycle and is executed when dummy bottles are inserted.
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### 2.10 Sterile Water Preparation Unit – Unitherm H
This unit supplies sterile water to the bottle rinser during production and provides sterile water to the entire system during startup cycles.
Specifically, Unitherm provides sterile water for the following operations:
- Rinsing containers during production
- Cooling the filler during SIP phase
- External rinsing of machines during SOP phase
- Combined sterilization and cooling of the filler during SIP phase (only applicable for Fillstar CX aseptic fillers)
- Foam preparation and post-foam rinse
- Internal rinse of the filler during "PRODUCT CHANGEOVER" cycles
For Fillstar CX aseptic fillers used to fill both non-carbonated and carbonated beverages, Unitherm can also use hot water to internally sterilize the filler.
**Sterile Water Generation**
Water is sent to the circulation section of the PHE (Plate Heat Exchanger), then conveyed to the heating section. After reaching sterilization temperature, it enters the保温管 (thermal insulation tube), achieves sterilization time, and then enters the final cooling stage. Once cooled to working temperature, it enters the filling area.
**Unitherm H Startup**
At startup, the factory must first perform an internal SIP sterilization cycle on the entire line before producing. Only after the machine reaches the required sterility can sterile water be supplied to the aseptic production line.
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### 2.11 Liquid Nitrogen Metering Unit
This unit is installed at the exit star wheel of the filler and injects a small amount of liquid nitrogen into the bottle to replace oxygen at the bottle mouth with internal pressure.
At very low temperatures (-196°C), a precise amount of liquid nitrogen flows into the bottle by gravity. At room temperature, as the liquid nitrogen vaporizes and expands, it replaces the oxygen inside the bottle and makes the bottle rigid.
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### 2.12 Microbial Isolation Chamber Ventilation and Pressurization System
Within this environmental control system-the microbial isolation chamber-all operations including bottle and cap sterilization, rinsing, filling, and capping take place.
These controls are ensured through the following measures:
a) Isolation from the external environment is strictly maintained through sterile air.
b) Positive pressure with sterile air is consistently maintained relative to the outside.
c) The bottle and cap sterilization areas are isolated.
Air entering the isolation chamber contains peracetic acid vapor and tends to vent preferentially into the environment. Therefore, this air needs to be chemically neutralized to remove acids and peroxides.
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