Both pasteurization and sterilization involve the use of heat, usually in a way which does not affect the fundamental characteristics of the product (in other words, it doesn’t cook it). However, while sterilization seeks to completely eliminate any micro-organisms which may be present in the product (and so typically uses higher temperatures or longer treatment periods, and is therefore more likely to have an effect on the product’s characteristics), pasteurization reduces the microbial load by a significant factor (for example by 5-logs), which in normal circumstances reduces them to a level at which they do not pose a hazard.

While simple plate heat exchangers may still be suitable for the pasteurization of simple fluids such as milk and fruit juices, more textured and viscous products, such as cooking sauces, creams and curds, require different solutions in order to maintain their quality and texture. In order to meet this diverse range of requirements, HRS Heat Exchangers has created its Thermblock packaged pasteurizer/sterilizer for food products for aseptic filling, as well as any other filling or packing method. Depending on specification and the intended use, Thermblock uses the most appropriate HRS tubular heat exchanger to deliver effective and efficient thermal treatment.

All HRS Thermblock systems allow for full adjustment of the heating-holding-cooling cycle of the product, so that it can be tailored to your product/s and method/s of working. They can also be used as HTST (High Temperature, Short Time) units, subjecting the product to high temperatures for a short time to minimize potential side-effects, such as organoleptic changes or nutritional losses).

There are three models of HRS Thermblock:

HRS Thermblock DTA Series
This features a double tube pasteurizer and sterilizer for food products containing pieces or particulates, such as fruit and vegetable dices. The sterilizer comprises double tube corrugated heat exchangers from the HRS DTA Series and also includes a positive displacement HRS BP Series piston pump which is specifically designed for products containing large pieces.

Options for the Thermblock DTA Series include reception, air-removal and product impulsion sections to help ensure the absence of air during the thermal treatment stage. The HRS Thermblock DTA Series is suitable for applications such as diced tomatoes, onions, and fruits; as well as products with large particles, such as soups and sauces, baby food, jams and marmalades.

HRS Thermblock AS Series
This is a packaged annular-space pasteurizer and sterilizer solution for thermal treatment for pasteurizing and sterilizing food products with high viscosity. The sterilizer is composed of concentric tube heat exchangers, or annular space heat exchangers from the HRS AS Series, which are particularly suitable for high viscosity products without particulates. Product flows in the central annular space, while the heating or cooling media passes through both the internal and external jacket.

The sterilizer can also include a high pressure piston volumetric pump with frequency converter capable of working pressures up to 450 psi, suitable for high viscosity products such as tomato paste or some purees. For lower pressure applications (up to 235 psi), or products with particulates, the HRS BP Series of piston pumps is recommended. The HRS Thermblock AS Series also features an automatic cleaning in place (CIP) system and is suitable for products including: tomato pulp and paste, ketchup and pizza sauce, fruit puree and concentrate, jams and marmalades etc.

HRS Thermblock M Series
The M Series is for food with low or medium viscosity. The sterilizer is composed of multi-tube corrugated heat exchangers from the HRS MI Series and HRS MR Series. A key feature is that it can be designed to include direct or indirect energy recovery, which means that up to 90 per cent of the energy can be reused, greatly reducing overall energy consumption and improving the return on investment.

Typical applications for the HRS Thermblock M Series include: juices and beverages, fruit and vegetable purees and concentrates, milk and dairy products, and smooth soups and sauces.

Offering a comprehensive range of pasteurization and sterilization options for food and drink producers, and with more than 30 years’ experience around the world, HRS Heat Exchangers are ideally placed to help you find the ideal pasteurization or sterilization solution for your process.

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