The vacuum cooling machine operates in a sealed cooling chamber using a water ring vacuum pump, a steam ejector, and a heat ex-changer. It creates a vacuum, causing the moisture in the food to boil at a lower boiling point, absorbing heat from the food, achieving rapid cooling while controlling bacterial growth.
The vacuum cooling makes use of the heat-absorbing effect of water boiling. When a liquid boils, it absorbs heat, lowering its own temperature and the surrounding environment. The boiling point of water decreases with decreasing pressure, reaching 0 ℃ at 610Pa pressure. By intentionally reducing the pressure and allowing the water in the food to boil at a low temperature, high-temperature food can be rapidly cooled without the need for additional refrigeration methods, improving production efficiency and food safety.
The vacuum system comprises a water ring vacuum pump, a steam ejector, and a heat ex-changer. Initially, the system uses the water ring pump to remove air, rapidly reducing the pressure inside the cooling chamber. Subsequently, the steam ejector is activated to further increase the vacuum level. The heat ex-changer operates throughout, facilitating the rapid condensation and contraction of high-temperature water vapor within the pipes, expediting the heat exchange. The system is equipped with a servo-controlled valve, capable of precise control like stepwise pressure reduction and pulse pressure variation.
Microorganisms are the primary culprits behind food spoilage and deterioration. Common food-borne microorganisms like E. coli and Salmonella thrive within a temperature range of approximately 10 to 50 ℃, known as the “temperature danger zone”. Vacuum cooling is remarkably fast and significantly reduces the food's residence time within the danger zone, inhibiting microbial reproduction and extending the food's shelf life.
The vacuum cooler utilizes advanced control technology, employing servo systems to synchronize adjustments in boiling point and pressure. This facilitates swift, medium-speed or slow-speed cooling modes, allowing for the tailoring of cooling curves to match dish-specific cooling requirements. This intelligent variable-speed cooling system also incorporates features such as splash prevention, enhancing its overall functionality.
