Steritwin
For some very special (value added) product types requiring a UHT process at an extremely high temperature (upto 320 F) Stork developed the Steritwin. This is a combined direct and indirect heating system.
The indirect heating system consists of a Stork Sterideal, a system that has already proved its worth all over the world. In the Sterideal, the greatest portion (86%) of the energy is regenerated, which makes the Sterideal an extraordinarily energy efficient system.
In the direct heating system, which is therefore only used at sterilization temperatures higher than 275 F, saturated steam is injected into the milk product, which is preheated in the Sterideal to approximately 275 F.
The temperature of the milk can then be raised to 305.6 F and the milk is maintained at that sterilization temperature for several seconds. Rapid cooling in a flash vessel follows this, in which the water that was injected into the milk in the form of steam is evaporated. The milk is subsequently cooled further by passing it through several heat exchangers and then delivered to the filling machine or an aseptic tank.
