Steritherm VLA
Increase product microbiological stability with the Alfa Laval Steritherm™ VLA aseptic sterilizer. Purpose-built for demanding food processes, it eliminates microorganisms that cause spoilage in medium- to high-viscosity products without compromising quality. This tubular heat exchanger delivers gentle, uniform heating and cooling to protect both process and product quality, while maximizing uptime and minimizing maintenance.
Skid-mounted tubular sterilizer for viscous, fibrous or particulate foods
- Optimized for high-viscosity, fibrous or particulate products
- Flexible processing of diverse formulations at varying production capacities
- Gentle treatment with uniform heating and cooling
- High uptime due to robust, long-run operation
- Low maintenance due to no moving parts
Sterilize medium- to high-viscosity products, with or without fibres and particles, using this aseptic sterilizer. Its advanced design provides higher heat transfer efficiency than conventional tube-in-tube systems. Versatile and cost-effective, it uses the Alfa Laval Viscoline annular heat exchanger to deliver gentle, high-temperature treatment with precise holding times for reliable sterilization. It protects product safety and quality throughout processing and packaging.
The skid-mounted tube sterilizer simplifies delivery, installation, and maintenance. Optional configurations support your production needs, including:
- integration of the Alfa Laval Alrox deaeration module for air removal
- indirect heat recovery for improved energy efficiency
- high-pressure design for demanding high-viscosity products such as purées, jams, soups with particles, and tomato-based products
How the aseptic sterilizer works during continuous thermal processing
The Steritherm VLA uses the Viscoline VLA-4 annular tube heat exchanger, in which the product flows between two concentric pipes, each surrounded by heating or cooling media. The media flows in a direction counter-current to the product flow through corresponding annular gaps between the outer product pipe and the shell pipe, and between the inner product pipe and the pipe in the centre. The use of corrugated pipe surfaces improves heat transfer efficiency between the media and product.
Superheated water at 125 °C (257°F) pre-sterilizes the Steritherm VLA for 30 minutes before allowing any product to flow into the unit. The product enters the balance tank, and a pump transfers it to the first heater, where circulating hot water raises the product to the required sterilization temperature. It then passes through a tubular holding cell for the necessary residence time for effective treatment.
Cooling the product occurs in two stages – first with tower water, then chilled water – before entering the aseptic filler tank. If the temperature falls below the set point, a diversion function prevents any untreated product from reaching the filler.
The product is cooled in two stages – by tower water and then by chilled water – before it enters the aseptic filler tank. Should the heat treatment temperature drop below a pre-set value, a diversion function ensures no untreated product reaches the filler. The arrangement enables production to restart after attaining the correct temperature without requiring re-sterilisation with water for high-acid products with a pH of 4.5 or higher.
Other versions include indirect heat recovery, combination with an Alfa Laval Alrox deaerator module and, in case of very highly products, special high-pressure designs.
Aseptic sterilization
Aseptic sterilizer flow chart
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Food system services
Alfa Laval Food system services help extend the performance of your food systems by maximizing the performance of your processes. This enables you to:
- Continually improve your operations to maintain competitive advantage
- Focus on uptime, optimization and availability
- Maximize return on investment throughout the life cycle of your food systems
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