For UHT sterilization at extremely high temperatures (up to 160°C), Stork has developed the Steritwin. This is a combined direct and indirect heating system which makes it possible to achieve these high temperatures with minimal energy costs.
Steritwin, for High Temperature UHT Sterilization
The Steritwin consists of a Sterideal, which heats the product to approximately 80°C (for ultra short heating, best product quality) or 130°C (high efficiency heating, best economy), after which the direct heating system raises the temperature to a maximum of 165°C by steam injection. This combined technology makes the Stork Steritwin far more energy efficient that a system which relies solely on direct heating. The Steritwin is the ideal system for eliminating Heat Resistant Spore Formers (HRS).
Thanks to its unprecedented flexibility and energy efficient operation, the Stork Steritwin is the most futureproof UHT system there is. The entire process is regulated and monitored by advanced computer controls. A fast changeover from the indirect heating process to the combined process is simply a matter of opening and closing a few couplings on the distribution panel. Consequently, you are assured of the most energy efficient operation under all conditions. This means that a Steritwin offers you the assurance that you can give every product the most efficient UHT treatment possible - both now and in the future.
Features and Specifications
- UHT treatment up to 160°C
- Energy efficient
- Flexible
- High-grade control engineering
- Effective elimination of HRS
The Steritwin consists of two units: an indirect heating system and a direct heating system. Depending upon the required process (heating to at most 140°C or to approximately 160°C) use can be made of the indirect heating system on its own or a combination of the two systems. Indirect heating takes place in an extremely energy efficient Sterideal, a system that has already proved its worth all over the world.
In the direct heating system, saturated steam is injected into the milk product, which is preheated in the Sterideal to approximately 135°C. The temperature can then be raised to approximately 160°C. This is followed by rapid cooling in a flash vessel.
HRS (Heat Resistant Spore Formers) are bacteria that form spores and survive a normal UHT treatment (up to 140°C) and therefore remain behind in the milk. These spores can only be destroyed with a temperature treatment of approximately 150°C. The Steritwin is therefore the ideal sterilizer for solving problems of this nature too. You only use the direct heating system when it is necessary (in the warmer months of the year when there is a risk of HRS contamination), while in the other periods of the year you use the energy efficient indirect heating system on its own.
Stork Hydromatic Continuous Sterilizer
The Stork Hydromatic continuous sterilizer consists of four or more towers or ``legs``, each with a height of up to twenty metres. The first leg serves as a preheating section, in which a hydrostatic column with serves as an inlet lock. The second tower comprises the sterilizing section, where the product is heated to the requisite sterilization temperature with the help of steam, a steam/air mixture or superheated water. After leaving the sterilizing section, the product carrier ascends through the hydrostatic cooling leg. With the pressure gradually decreasing and the product gradually cooling, additional cooling is provided by spraywater jets. Finally, the cooling cycle is completed in the fourth tower. The Hydromatic can be equipped with an option that enables the containers to be rotated during processing. The constant movement of the air trapped in the container causes an agitating effect which provides more uniform heating and reduces the process time, especially in the case of viscous products.
The Vario Cassette for Vulnerable or Less Common Packages
Stork has developed the Vario Cassette for the sterilization of vulnerable or less common packages. The packages are arranged and confined in the Vario Cassettes so that they are prevented from making any undue movements. Rendering the Hydromatic continuous sterilizer suitable for the physical handling of an entirely different product/package combination requires a minimum of re-tooling, only involving the interior re-arrangement of the Vario Cassettes. No wonder that this makes the Hydromatic continuous sterilizer the most eligible choice for high-capacity applications, requiring a maximum of flexibility.
The Vario Cassette is capable of handling any type of container, including future containers which have yet to be conceived. In addition, the Vario Cassette can be used in different sterilization systems. Consequently, the Vario Cassette is the cornerstone of the Flexible Future concept introduced by Stork Food & Dairy Systems. Flexible Future offers processors the opportunity of gearing their production systems precisely to their products and output requirements. The introduction of a new product, for example, initially only requires the application of a filling machine, a packer and unpacker for the Vario Cassette, a conveyor system and one or more retorts. The Vario Cassette is a robust stainless steel container with perforations in the walls and base to assure proper heat transfer to the products during the sterilization process.
Depending upon the product to be sterilized, inserts are fitted in the Vario Cassette, thus ensuring optimum handling conditions for that particular product. The Vario Cassette is designed in such a way that without further modifications it fits easily in the conveyor system of a continuous sterilizer. In addition, it is robust and ideal for stacking, and therefore also suitable for use in retorts. The Vario Cassette also allows the transport of the products to be treated from the filling machine, via the sterilization system, to the unloading station where the products are taken out of the cassette and placed in a tray, crate, box or other type of secondary package. As a result, the products are protected against damage throughout the production process and their handling is greatly simplified.
