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Beverages rich in nutrients such as vitamins and proteins, commonly found in supermarkets, offer various benefits to consumers. However, these components also make the beverages sensitive, as microorganisms can easily grow in them. This is where hot filling plays a crucial role in ensuring product safety and longevity.
For example, a glass of freshly squeezed juice or milk left in the air will spoil. This is because the air contains numerous microorganisms, which reproduce in the beverage upon contact, leading to spoilage. Through the hot filling process, the risk of microbial contamination is significantly reduced, preserving the beverage’s freshness and quality.
To extend the shelf life of such nutrient-rich beverages to 9 months or even 1 year, one effective method is hot filling, where the beverage is heated to a temperature that kills microorganisms before filling. Studies have shown that a hot filling temperature of 80-90°C achieves the best sterilization. This temperature varies with the beverage’s properties; for instance, acidic beverages, which have natural antibacterial properties, require lower hot filling temperatures.
By applying hot filling technology, manufacturers can safely package sensitive beverages while maintaining their nutritional value, flavor, and appearance for extended periods. This makes hot filling a preferred solution for the production of juices, dairy drinks, plant-based beverages, and other health-oriented products.
Application of Hot Filling in the PET Industry
Ordinary PET bottles can withstand temperatures of only 60-70°C, beyond which they shrink.
To meet the 80-90°C filling requirement, modifications are needed both in the PET raw material (to increase its melting point) and in the bottle-blowing process from preforms to finished bottles:
Increased weight: Hot-fill PET bottles are 50%-90% heavier than non-hot-fill ones. This extra weight enhances their strength to resist deformation caused by thermal expansion and contraction.
Different bottle design: To prevent inward shrinkage as the beverage cools after hot filling, bottle bodies are designed with “small windows”—similar to the respiratory membranes in human lungs—to buffer temperature-induced deformation.
Adjustments to the blow molding machine’s heating oven: Due to changes in PET viscosity, melting point, and weight, PIO HF series blow molding machines customize the furnace’s power and lamp to ensure preforms are fully heated before entering the mold.
Mold changes: Hot-fill bottles require rapid cooling to withstand high temperatures while maintaining transparency. Mold cavities must be polished to a high mirror finish, so high-strength mold steel (instead of aluminum alloy) is used for PIO hot-fill molds.
Mold heating process changes: Instead of cooling water, hot oil (typically above 120°C) is used in the hot-fill mold area.
Changes to the stretching rod: Unlike ordinary rods, hot-fill bottle rods use internal cooling gas for rapid internal cooling. PIO-HF hot-fill series ensure cooling gas reaches corners and reinforcing ribs for optimal
Air compressor adjustments: Hot-fill bottles require a blowing pressure of 40 kg, compared to 30 kg for ordinary bottles.
Refrigerated dryer changes: PIO-HF hot-fill air compressors are equipped with 2 refrigerated dryers (vs. 1 for conventional machines), with one providing enhanced cooling.
Our advantage: The new generation PIO-HF hot-fill blow molding machine is compatible with both hot-fill and non-hot-fill bottles. Through optimized programming and easy replacement of components (e.g., switching from cold water to hot oil in molds, quick stretching rod changes), it supports both processes on a single machine.
| Model | Unit | PIO2L-4HL | PIO2L-6HL | PIO2L-8HL | |
| Product | Maximum Volume for Product | L | 2 | 2 | 2 |
| Maximum Diameter for Product | mm | Φ105mm | Φ105mm | Φ105mm | |
| Maximum Mouth Size | mm | Φ38mm | Φ38mm | Φ38mm | |
| Maximum Height for Product | mm | 320 | 320 | 320 | |
| Maximum Height for Preforms | mm | 160 | 160 | 160 | |
| Mechanical Specifications | Clamping Distance for Mold | mm | 140 | 140 | 140 |
| Bottom Mold Stretch Distance | mm | 30 | 30 | 30 | |
| Bottle Spacing | mm | 120 | 120 | 120 | |
| Standard Thickness of Mold | mm | 210 | 210 | 210 | |
| Number of Mold Cavity | PCS | 4 | 6 | 8 | |
| Production Capacity BPH (Bottles/Hour) | BPH | 2000-3000 (@500ml) | 3000-4000(@500ml) | 4000-5000(@500ml) | |
| Heating Section | Number of Heating Ovens | PCS | 6 | 6 | 6 |
| Number of Heating Lamp Layers | PCS | 10 | 10 | 10 | |
| Number of Preform Seats (pcs) | PCS | 130 | 162 | 178 | |
| Electrical Parameters | Input Voltage | Customisation | 220/380V | 220/380V | 220/380V |
| Frequency | Customisation | 50/60Hz | 50/60Hz | 50/60Hz | |
| Applied Power | KW | 40-60 | 50-75 | 55-80 | |
| Installed Power | KW | 145 | 145 | 145 | |
| Usage of Compressed Air | Low Pressure Compressed Air Pressure | Bar | 7-8 | 7-8 | 7-8 |
| Low Pressure Compressed Air Consumption | m³/min | 1 | 1 | 1 | |
| High Pressure Compressed Air Pressure | kgf/cm² | 35-40 | 35-40 | 35-40 | |
| High Pressure Compressed Air Consumption | m³/min | 10-12 （500ml） 10 （1500ml） 11 （2000ml） | 14-16 （500ml） 14 （1500ml） 16 （2000ml） | 18-20 （500ml） 19 （1500ml） 22 （2000ml） | |
| Cooling Water (Water Temperature ≤18°C) | Water Chiller | HP | 1 set 10HP | 2 set 10HP | 2 set 10HP |
| Mold temperature controller | Mold temperature controller | kw | 2 set 12kw | 2 set 15kw | 2 set 18kw |
| Weights | T | 7 | 9 | 10 | |
| Equipment External Dimensions | Main Unit(L×W×H) | mm | 4800×1857×2550 | 6624×1857×2826 | 7104×1857×2869 |
| Whole Machine(L×W×H) | mm | 6350×3300×3170 | 8537×3024×3331 | 9338×3213×3251 | |
