SIGMATHERM - High Temperature Short Time Heating Systems
From Thermal Systems
High temperature short-time (HTST) SIGMATHERMare the preferred choice for the pasteurization of beverages and liquid foods such as juices, beer, milk, sauces, fruit and vegetable purees, tomato paste, jams and jellies, applesauce, liquid eggs, etc. These products are typically filled into refrigerated containers and have a limited shelf life of several days to several weeks.
- Low thermal load on the products
- Long life expectancy of the plant
- Low heating costs
- Compact construction
- Fully aoutomated control available
- Heat recovery up to 96%
A product passing through a high temperature short time heating system is preheated in the heat recovery section. It is then brought to pasteurization temperature in the heating section and held for a prescribed time in the holding tube before the temperature is lowered in the heat recovery section. It is finally cooled to a temperature for packaging and storage.
Process plants can be entirely based on the SIGMA plate heat exchanger which is capable of up to 96% heat recovery. SIGMAFLOW tubular heat exchangers and direct steam injection systems provide an alternative design for viscous, pasty, pulpy and particulate liquid foods.
Basic systems are supplied with hardware controllers and manually operated valves. Packages are also available with fully automated valves, instrumentation and control systems featuring touch screen and PLC control.
For extended shelf life (ESL) applications, higher temperature sterilization systems are offered for either high acid (pH < 4.5) or low acid (> 4.5) products. The design of these systems is similar to pasteurizers, but they usually feature more instrumentation and fully automatic control systems.
When combined with cold packing in refrigerated containers, these short-time thermal processing systems are known as ultra high temperature or UHT processors. When combined with packing into sterile containers at ambient temperature, the thermal processor must be an aseptic design.
For low acid ESL applications, regulatory authorities such as the FDA will be involved. Microbiological validation and review of control protocols are necessary to ensure the thermal processor and filler are working both safely and correctly.
Ideal for the pasteurisation prior to sterile packing or storing of beverages and liquid foods such as: juices, beer, milk, sauces, fruit and vegetable purees, tomato paste, jams and jellies, applesauce, egg products.
High temperature short time heating systems can be used for the cold packaging of food products in sterile containers via aseptic fillers into packages or barrels.
A product passing through a high temperature short time heating system is pre-heated in the heat recovery section, it is then brought to pasteurisation temperature in the heating section, held for prescribed time in the holding tube before the temperature is lowered in the heat recovery section, and finally cooled to the packaging or storing temperature of around 20-25 °C.
When a corresponding heat recovery system is installed for the cold processing of foodstuffs then the cooling section can be dispensed with.
The plants can be fitted with basic controls, with for example hardware-controllers and manually operated valves or with fully automated controls with, for example software-controllers, SPC and computerised process controls.