Pasteurization. Types of pasteurers

Pasteurization – heat treatment of liquids – got its name in memory of the French scientist Louis Pasteur. The purpose of pasteurization is the technological process of suppressing pathogenic forms of bacteria in food liquids, but preserving the beneficial properties of these fluids, with minimal energy input. The process of pasteurization – milk, beer, wine and other liquids (product) – energy-intensive. It consists in heating from 5 ° C to 72-73 ° C of the product, keeping it in time and rapidly cooling it to a long-term storage temperature without bacteria.

The product consumption (set by the customer) is from hundreds of kg / h to thousand kg / h. For the operation of the pasteurization unit, hot water of 76 ° C and a coolant (ice water, brine, service water) are required. The most common product requiring pasteurization is fresh milk after milking cows.

Let’s consider the variants of the designs of pasteurizers:

The simplest pasteurizer is capacitive, in special baths with a protective coating (enamel, stainless steel, etc.). The bathtub has shirts for hot water or steam and ice water. The raw milk is loaded into the tub and heated for prolonged pasteurization to 65 ° C and held for 30-40 minutes. Then cool with tap water and ice water until storage temperature.

After each pasteurization cycle, the bath is washed. Energy costs and labor costs are high, the price of pasteurization in a capacitive pasteurizer is the highest in comparison with other designs of pasteurizers. Another design of pasteurizers is tubular. Their heat exchange surface area is made of pipes. Pipes are made of stainless steel with a wall thickness of 2-3 mm. Such a pasteurizer consists of separate apparatuses. Fresh milk is pumped into the first recuperator of heat, where it is heated in a closed flow by hot milk coming out of the holder. The heat recovery of up to 55% and the product flow closed in the apparatus ensure the energy efficiency of the installation.

After the heater, a product holder with a predetermined time and pasteurization temperature is followed. From the holder, the product again enters the recuperator, where it gives off heat to the fresh product. Then follows the milk cooler in the installation, the cooling product first with process water and at the outlet, through the cooler with “ice water” (+ 2 ° C) or with a coolant (brine).

The installation of a tubular pasteurizer is cumbersome and time consuming, since hygienic apparatus requires frequent disassembly and washing of pipes that come in contact with the product. Technical progress in the forties of the last century led to the creation of lamellar pasteurizers. The modern plate pasteurizers produced by the PSPC “Ankor-Teploenergo” combined into a single unit on a common frame have the following technical and economic advantages: low laboriousness and availability for disassembly, washing, inspection of plates on both sides of the heat transfer surface and assembly of the apparatus; The pasteurizer meets all the requirements of sanitation, reliability, durability, safety of equipment for food production; The energy intensity is optimized, the heat recovery coefficient is increased to 83-90%; Pressure plates are clad with stainless steel; “Milk” fittings, no parts that are prone to corrosion; According to the customer’s initial data, the necessary calculations (thermal, hydro mechanical, strength, etc.) can be performed; The customer receives a technical and commercial offer free of charge. Pasteurizer is supplied with the instruction manual, in a minimum time with a guarantee.