Heat Exchangers

Heat transfer principles

Two substances must have a different temperature in order to transfer heat. Heat always flows from the warmer substance to the colder. The greater difference, the faster it equalizes.

 All heat transfer in Dairies take place in the form of direct or indirect heating e.g. a Pasteuriser unit can have a small soldered PHE where steam goes direct in the water, the water gets hot and used indirectly in The pasteurizer unit to heat the milk to desired pasteurising temperature.

The same thing happens in milk cooler e.g. in the milk reception, the only difference is in the media — Ice water, not steam.

Illustration from Alfa Laval Dairy Handbook

Tubular Heat Exchanger

Illlustration from Alfa Laval Dairy Handbook

Tubular Heat Exchangers

Will often be used in UHT production, or on liquid with high viscosity and lower heat transfer.

The efficiency is lower in a THE, but can operate with longer intervals between cleaning.

The illustration to the left shows the end of a multi-tube heat exchanger

Scraped Surface Heat Exchanger

Scraped Surface Heat Exchanger

Is designed for heating and cooling of viscous, sticky and lumpy products as well as for crystallisation of products.

The operating pressures on the product side can be very high — Up to 40 bar.

Illustration from Alfa Laval Dairy Handbook

Do you need a new Pasteuriser -- Mejeriet can provide you with the components to set up an efficient production line.

Based on the numbered step stone below. Mejeriet shall be pleased to quote you the equipment you need.

Different types of Pasteurisers

11.01– Plate Heat Exchanger — Set-up for low viscosity product with no solid particles.

11.02 — Plate Heat Exchanger — Set-up for Heavy viscosity like Cream and Fruit pulp — No lumps.

11.03 — Multi Tubular Heat Exchanger — Suitable for very high temperature and high pressure, e.g. UHT plants.

11.04 — Mono Tube Heat Exchanger — Suitable for high temperature and high pressure — Lumps up to pipe diameter can pass.

11.05 — Scraped Surface Heat Exchanger — Suitable for sticky anf lumpy liquids, e.g many of the desserts your Dairy can make.

11.06 — Shrouded spiral holding tube. — Suitable if any of your heated products need prolonged holding time at a certain temperature.

Illustration from Alfa Laval Dairy Hand book