Thermal systems

Comprehensive and product-friendly. The techniques we employ for the thermal processing of liquids such as milk and fruit juice ensure that there is no impairment of the product.

Tubular heat exchangers - our specialisation

For thermal food processing, we can supply tubular heat exchangers with the following performance capacities:
Milk: 500 – 35,000 l/h
Cream: 100 – 12,000 l/h
Fruit juice: 500 - 35,000 l/hMax. product heat temperature: 150°C
In the milk and beverage industries, tubular heat exchangers can be used for both heating and cooling products. We can specifically design these for use in pasteurisation and the production of ESL and UHT milk.

Excellent and systematic processing in accordance with EHEDG guidelines guarantees a high level of both product and process safety. Other benefits:

  • Long operating times,
  • Minimal product loss during start-up and shut-down
  • Minimal cleaning and maintenance needs 


Tubular heat exchangers

We offer four different techniques for the production of ESL (extended shelf-life) milk; the one we employ depends on the specific requirements of the customer:

1. Direct thermal processing by means of steam injection
The pasteurised, homogenised and standardised milk is first heated in a heat exchanger. Steam is then directly injected to instantaneously heat the milk to 125°C thus immediately eradicating any microorganisms present. The resultant condensate that is precipitated in the milk is subsequently removed by vacuum evaporation at approx. 60°C.  
2. Direct thermal processing by means of steam infusion

In this procedure, the pasteurised, homogenised and standardised milk is first heated in a heat exchanger. The pre-treated milk is then sprayed into a steam chamber in which it is heated to 125°C, immediately eradicating microorganisms. The water that is introduced into the milk during the process is subsequently removed by vacuum evaporation at approx. 60°C.  
3. Indirect thermal processing using a tubular heat exchanger
Using a tubular heat exchanger, the pre-treated milk is heated to 125°C. To eradicate microorganisms, the milk is maintained at this temperature for a specified time and is then subsequently cooled. Water is used as a counter-flow medium.

4. Microfiltration
In the ideal situation, it is possible to use raw milk as the starting material for the production of ESL milk. In this case, the fat must first be removed from the milk as this would otherwise impair the effectiveness of the filtration process. The resultant skimmed milk is filtered using ceramic modules; the process removes 99.9% of microorganisms. The fat content of the previously thermally treated full milk is first adjusted to the required level in an online standardisation unit. The excessive milk fat can be removed directly after passage through the separator and used as raw cream for the manufacture of other products.

All the techniques described above provide for a guaranteed 99.9% level of elimination of microorganisms. If ESL milk is continuously refrigerated, it has a shelf life of up to 30 days in a chiller cabinet. These techniques are also product-friendly; in other words, they have no negative effects on flavour or other milk-specific characteristics.



Here at ELIQUO PROTEC we offer two different UHT systems designed for the aseptic processing of liquid to highly viscous products:

  • An indirect UHT processing system with tubular heat exchanger
  • A direct UHT processing system employing steam injection or infusion

Using these techniques, it is possible to aseptically process liquids to highly viscous products in a UHT system. This means that one system provides the flexibility of processing a complete range of liquids, from UHT milk to highly viscous products.

The product quality, product safety and cost-effectiveness are the criteria that determine which of these systems is most appropriate in a given situation:

Product Quality
Consistently high product quality can be achieved by means of the selection of the appropriately product-orientated UHT system. The determining factors for the system design are the technological aspects relevant to the product, such as temperature, heat maintenance time and homogenisation technique.

Production safety
We develop and construct all our UHT systems in accordance with the requirements of the EHEDG guidelines. Use of suitable parameter settings (for temperature and time) and the sterilisation of the UHT system prior to operation will ensure sterile bacteriological environment.

UHT systems are cost-effective in operation due to the high level of heat recovery, the low level of product loss, their low energy requirements, their long operating times and minimal cleaning and maintenance needs. We are continuously enhancing the cost-effectiveness of our systems and ensure that they are as environmentally-friendly as possible.

Our range of thermal processing and systems expertise

Indirect thermal tubular heat exchanger systems for

  • Ultra high temperature processing
  • Pasteurisation
  • Pre-thermal treatment
  • Cooling

Direct thermal processing systems

  • Using steam infusion
  • Using steam injection


UHT system

10,000 l/h


  • flexible output: 7000 - 10,000 l/h
  • combined direct/indirect thermal processing system
  • up to 88% heat recovery
  • operating time > 12 h
  • direct thermal processing by means of steam injection for the production of ESL milk
  • indirect thermal processing for the production of mixed beverages, such as chocolate, vanilla and strawberry-flavoured milk drinks and also for the production of fruit juices
  • tubular heating element; adjustable 0 - 30 min

Special features

  • the production of condensed milk is possible thanks to the specific component combination
  • valve operation system providing for minimal product loss on start-up and shut-down
  • a coupling panel allows operation of the homogeniser in septic and aseptic status

Syndicat Intercommunal, Step Bettembourg

Sep. 2007 I. BA/ June 2009

Contract value
EUR 36.5 million