Direct heating units, as opposed to indirect units, use steam injection to speed up the heating and cooling process so that the impact of heat on product quality is minimised.
Run at higher operational cost than indirect units, such heating systems are designed to be used in the manufacture of premium dairy and soy products.
With its new Tetra Therm Aseptic VTIS unit, Tetra Pak aimed to reduce the cost and product loss associated with direct heating systems.
Cost savings
Compared to the previous generation of direct UHT heaters, the company claims that the Tetra Therm Aseptic VTIS reduces operating cost by 15 per cent.
In addition, the Swedish firm said the direct heating unit cuts product loss by up to 40 per cent compared to current industry standards and boosts running time by up to 60 hours.
To deliver such improvements in operating efficiency, Tetra Pak said it introduced a number of design changes.
Fredrik Gunnarsson, product manager for Tetra Therm Aseptic VTIS, told this publication that improved running time was one of the biggest changes in the new system.
Design changes
Running times between cleanings have been increase from 30 hours with previous generations to up to 60 hours thanks to an improved steam injector and holding cell design.
Other significant changes include a new double tank system, with one tank for product and one for water, which is designed to reduce product loss in the mix phase. This system makes it possible to completely empty the main balance tank of water before filling it with new product.
The flash cooling system has also been updated so that it includes a new conically designed topped vessel and built-in spray condenser, rather than a conventional external condenser.
Finally, steam consumption has been cut by 5 per cent compared to previous models thanks to a preheating process that uses heat-treated product rather than hot water to transfer heat to the cool inlet product.
The Tetra Therm Aseptic VTIS can be configured to match the specific needs of customers and is available on its own or as part of a Tetra Lactenso Aseptic dairy production solution.