Tube-in-Tube Pasteurizers are heat exchangers used to pasteurize liquids, typically in the food and beverage industry. They consist of two concentric tubes—one inside the other. The liquid to be pasteurized flows through the inner tube, while a heating or cooling medium (such as hot water or steam) flows through the outer tube. This design allows for efficient heat transfer to the liquid without direct contact between the liquid and the heating medium.