Steritherm VLM
Effective food sterilization technology maintains product microbiological stability. The Alfa Laval Steritherm™ VLM tubular sterilizer treats low- to medium-viscosity products with fibres and particles. It optimizes food sterilization using a tubular heat exchanger for gentle, uniform heating and cooling, while maximizing uptime and minimizing maintenance.
How a tubular sterilizer ensures food safety in aseptic manufacturing processes
- More uptime in fouling-prone applications
- Reliable, cost-effective operation with long run times
- Versatile handling of various capacities and product formulations
- High hygiene levels through effective cleaning-in-place
- Low maintenance due to no moving parts
Choosing the right equipment is critical to protecting product integrity. The Steritherm VLM tubular sterilizer prevents spoilage while maintaining product quality throughout production. It achieves higher heat transfer efficiency than tube-in-tube sterilizers.
At its core is the Alfa Laval Viscoline™ multitube tubular heat exchanger, engineered for robust, highly effective sterilization. This advanced tubular sterilizer treats products ranging from milk and eggs to fruit and vegetable purées, and pulp-containing fruit juices, with precision and consistency. It ensures food safety while preserving product quality across a wide range of formulations.
The pre-assembled, skid-mounted unit integrates seamlessly between aseptic tanks and fillers, simplifying installation and operation. This compact design enhances safety and reduces maintenance throughout the packaging process – a key advantage in continuous aseptic manufacturing processes.
Optional configurations include:
- Alfa Laval Alrox deaeration module for air removal before sterilization
- Direct and indirect heat recovery systems to improve energy efficiency
Understanding how the tubular sterilizer works
Sterilization
Before production begins, the Steritherm VLM undergoes sterilization-in-place. Superheated water at 125 °C (257°F) circulates through the unit for 30 minutes to ensure hygienic start-up conditions.
Balance tank
The product enters a balance tank, and a feed pump transfers it to the heat exchanger. A flow meter sends signals to the pump, ensuring a constant feed rate. Temperature and pressure transmitters continuously monitor the inlet temperature and pressure.
Indirect pre-heating (regeneration)
A dedicated closed water loop preheats the cold product. Indirect energy recovery reduces the need for external heating and cooling, improving overall energy efficiency. The product is maintained under higher pressure than the heating medium to ensure safe and stable processing.
Final heating and holding
Final heating to the sterilization temperature is achieved through hot water recirculation. A dedicated unit generates hot water by means of steam. A temperature transmitter at the heat exchanger outlet measures product temperature and sends data to the control system. The control system regulates the steam input via a modulating valve to maintain precise product sterilization conditions. The product then flows into an insulated holding tube, where it remains for the time required to achieve sterility.
Cooling
To reach the required product filling temperature, the cooling process may be carried out in three stages as required:
- Indirect cooling through the same closed water loop used for the preheating, improving overall energy efficiency
- Cooling with tower water
- Final cooling with chilled water or glycol solution in a counter-current flow
To ensure the correct final temperature, a temperature transmitter continuously measures the flow rate of the final cooling media. It sends signals to the control unit via a modulating valve installed on the cooling media pipeline and measures the product outlet temperature.
Cleaning-in-Place (CIP)
Under normal conditions, all product-contact surfaces are cleaned without dismantling the Steritherm VLM. Cleaning frequency depends on the product characteristics and operating temperatures.
Control system
The sterilizer operates automatically. Start and stop functions, set point and PID control parameters can be set and inspected. The control system displays relevant process data, including plant status, temperatures, flow rates, and alarm status.
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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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