Steritherm VLA
Increase the microbiological stability of products by removing or inactivating microorganisms that cause product spoilage. The Alfa Laval Steritherm VLA is an aseptic heat treatment system that sterilizes medium to high viscosity products. Based on a tubular heat exchanger, it ensures gentle product treatment and uniform heating and cooling. Versatile and robust, this aseptic sterilizer maximizes uptime and minimizes maintenance.
Skid-mounted tubular sterilizer for fibrous, particulate or viscous products
- Greater production flexibility for, high-viscosity products and those containing fibres and particles
- Versatile handling of various capacities and product formulations
- Gentle treatment with uniform heating and cooling
- Reliable, low-cost operation with long times due to higher heat transfer efficiency than tube-in-tube designs
- Near maintenance-free operation due to no moving parts and low service requirements
Sterilize medium to high viscosity products with or without particles using the Alfa Laval Steritherm VLA. Versatile and robust, this aseptic tubular sterilizer has the Alfa Laval Viscoline annular heat exchanger at its core. It combines high temperature and holding time for effective sterilization to ensure product safety throughout the packaging process.
Delivery, installation, operation and maintenance are quick and easy. Special models are available for:
- the removal of air from the product before treatment with integration of the Alfa Alrox deaeration module
- indirect heat recovery to improve energy efficiency
- operation under high-pressure conditions for high-viscosity products such as purées, jams, soups with particles, and tomato 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.
