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With the promotion and application of ultra clean and sterile filling processes in beverage packaging, products such as fruit juice, tea drinks and sports drinks are gradually being replaced by sterile cold filling processes from the original hot filling process (filling temperature 85-92 °C). The advantages of aseptic cold filling process include low production cost

light bottle weight, reduced consumption of high-pressure gas and heating energy, significant energy saving and consumption reduction; Secondly, it can be filled at room temperature with minimal loss of nutrients, which can maintain the taste, color and flavor of the beverage while ensuring its shelf life. In order to meet the process requirements of ultra clean and sterile filling, for the integrated equipment of sterile blowing, filling and spinning, the bottle blowing machine adopts the sterile blowing process to produce bottles, reducing the contamination of bottles by bacteria during the bottle preform transportation and blowing process, efficiently killing bacteria and providing guarantee for dry or wet sterilization of sterile filling.

The main structure of aseptic bottle blowing process

1. Organize the fully enclosed bottle embryo system

During the process of organizing preforms, in order to improve the hygiene of preforms, prevent dust pollution during preform loading, sorting and transportation, an openable dust cover is designed above the preform hopper. When the number of preforms is below a certain height, the dust cover automatically opens and the tipping machine is linked to pour preforms until it stops and the dust cover automatically closes. In the process of lifting, organizing and transporting bottle preforms, protective covers and transparent windows are designed. The bottle preforms operate in a closed environment, reducing contact with the outside air and minimizing dust adsorption due to static electricity, thereby reducing pollution during the process of organizing bottle preforms. The bottle preform system should be regularly maintained and inspected to remove stains from the conveyor belt, drum, and slide surface and to maintain the cleanliness and hygiene of the working surface.

2. UV sterilization of bottle mouth

During the production, storage and transportation of bottle embryo, due to temperature, humidity, air and other environmental factors, bacteria and other microorganisms will grow on the surface of bottle embryo. In order to disinfection and sterilization bacteria and microorganisms, a certain number of ultraviolet light tubes are installed on both sides of the glide slope and near the bottle mouth. UV light tubes are used to emit short wave ultraviolet (UV-C) light to illuminate the bottle mouth to kill bacteria. Under the ultraviolet radiation, DNA and RNA in the cell tissue are destroyed and lose their activity, preventing the regeneration of daughter cells and killing bacteria, viruses and other microorganisms. According to the blowing speed and production capacity, the UV light irradiation time at the bottle mouth is 5-10 seconds. The UV lamp is installed in a closed space to avoid direct UV light irradiation on the human body. Research has shown that ultraviolet radiation with a wavelength of 240-280nm in the C-band has a highly efficient bactericidal effect, with the peak value of 253.7nm ultraviolet radiation having the strongest bactericidal ability. To improve the penetration rate and sterilization effect of ultraviolet rays, ultraviolet lamps should be regularly maintained and serviced. Use alcohol cotton balls or gauze to wipe the lamp tube and remove dirt on the quartz glass sleeve.

3. Bottle preform electrostatic dust removal

The purpose of electrostatic dust removal is to remove the dust in the air adsorbed by static electricity inside the preform tube. The dust removal system mainly consists of three parts: (1) preform transfer mechanism, which realizes the transfer of preforms and the up and down movement of the blowing nozzle. The transmission system is associated with the heating machine and is driven by a synchronous belt to drive the star wheel disc and a cam to drive the up and down movement of the blowing nozzle; (2) The ionization device and power controller convert 24V voltage into 4-8KV and 120uA current. The high-pressure discharge needle inside the nozzle ionizes the sterile compressed air (2-4 bar) to generate positive and negative ions, neutralizing the dust adsorbed on the surface of the PET preform due to static electricity; (3) The dust generated by the ion dust removal device is collected, filtered and discharged by the vacuum cleaner.

The electrostatic precipitator nozzle is paired with the preform and through experiments and ion detection, it can effectively remove small particles and impurities such as dust and debris adsorbed inside the preform tube, meeting relevant hygiene requirements.

4. Bottle embryo H2O2 steam sterilization

To further kill bacteria and other microorganisms inside the bottle mouth and embryo tube, considering the heating chain structure and heating process, H2O2 steam with a certain flow rate, concentration and temperature is directly sprayed into the bottle mouth and embryo for sterilization. A 2-4 μ m condensation film will form on the inner surface of the embryo, as H2O2 has strong oxidizing properties and can destroy the proteins of bacteria and other microorganisms; The surface area of PET preforms is small and the consumption of H2O2 solution is low, making it very suitable for sterilization treatment of PET preforms.

The sterilization device mainly consists of three parts: (1) flash evaporation device, where a certain concentration of H2O2 solution (25-30%) is mixed with sterile low-pressure gas and heated to form steam, with a controlled temperature of 130 ℃; (2) Bottle preform driving device, the heated bottle preform is transported by a robotic arm to a star wheel, which is driven by a synchronous belt and drives the bottle preform. The shell shaped nozzle moves up and down along the cam and high-temperature H2O2 vapor is sprayed into the bottle mouth and bottle preform through the nozzle hole, forming a condensation film that covers the inner surface of the bottle mouth and bottle preform. H2O2 releases strong oxidative hydroxyl groups, destroys DNA, RNA, etc. in bacterial cell tissues and kills bacteria; (3) Extraction device, in order to prevent residual H2O2 steam from having adverse effects on carbon steel parts, a ventilation device is designed at the top of the sterilization hood. The steam is discharged into the exhaust gas collection pipeline through a fan and ultimately decomposed into water and oxygen.

5. Sterile high-pressure gas blowing bottle

The high-pressure gas used in the bottle blowing machine is sterile high-pressure gas, which can prevent bacteria and other microorganisms from contaminating the bottle during the blowing process. The compressed gas produced by the air compressor (25-38 bar) is dried and roughly and finely filtered (with a filtration accuracy of 3-5um and a maximum residual oil content of 5mg/m3), but the air quality does not meet the sterile requirements and needs further treatment to effectively filter particles, impurities, water vapor, oil and gas, and microorganisms in the gas; The sterile high-pressure gas processing system consists of three filters connected in series.（1）The high-pressure precision filter is used for dust removal, oil removal and water removal, with a filtration accuracy of 0.01um and a maximum residual oil content of 0.01mg/m3;（2）Activated carbon filter, capable of adsorbing oil vapor with a maximum residual oil content of 0.003mg/m3; （3）The sterilization filter adopts a high flow and high-temperature resistant sterilization filter element with a filtration accuracy of 0.01um, effectively removing bacteria and other microorganisms. To ensure the normal operation and sterilization effect of the filter, it is necessary to maintain and upkeep the filter element correctly. The replacement cycle of the filter element is 1 year/6000 hours; Change cycle of 6 months/1000-3000 hours; The replacement cycle of the sterilization filter cartridge is 6 months/1000-3000 hours. Depending on usage, the sterilization filter cartridge can be sterilized with saturated steam at a temperature of 120-130 ℃, a pressure of 2-3bar, for 20-30 minutes, 1-2 times per week/month with a limit of 50-100 steam sterilization times.

6. High pressure gas pipeline sterilization

The blowing pipeline system of the bottle blowing machine is complex with various connection points and sealing methods. There are many blind spots and spaces and compressed air staying in the blind spots for a long time can breed bacteria and other microorganisms. Considering the material of the pipe fittings, the structure and performance of the blowing valve and sealing cylinder, it is necessary to regularly sterilize the trachea and related pneumatic components to create a good sterile high-pressure airway environment. The high-pressure gas pipeline uses high-temperature steam or hydrogen peroxide steam for sterilization. Considering the condensation and dew formation of steam, the dead zone of the pipeline will produce condensed water and be difficult to discharge. Prolonged retention of condensed water is not conducive to a sterile environment. This method needs further consideration and optimization.

7. Sterilization of bottle type conversion parts

The dial plate, robotic arm and stretching rod in contact with the bottle preform, as well as the mold cavity and bottle star wheel related to the bottle shape, need to be regularly cleaned and sterilized on their working surfaces. Every 120-150 hours per week, the mold cavity, parting surface, and robotic arm should be wiped with degreased cotton dipped in 75% alcohol to effectively remove dirt and microorganisms from the working surface.

8. Positive pressure environment in the bottle blowing area

Due to the use of heated hydrogen peroxide steam sterilization for the preform, some hydrogen peroxide steam will remain in the preform tube. The preform is sent to the bottle blowing system to complete the blowing process. As the bottle body increases and high-pressure gas dilutes, the exhaust gas contains trace amounts of hydrogen peroxide. Considering the oxidizing nature of hydrogen peroxide and its impact on carbon steel parts, two high-efficiency fans are designed at the top of the main unit to maintain the blowing space in a positive pressure environment, which can effectively improve the hygiene of the blowing space.

Author: Robin He