Product freezing time, we need to know to ensure efficient drying

Why you must pay attention to this parameter when using a freeze drying machine, because this is also one of the important factors to dry products for good quality and efficiency with different drying outputs. In this content, Mactech will analyze the product freezing time to help customers understand this information.

In a freeze drying process, the first step when starting to dry the product is the freezing stage of the product. Because sublimation drying is based on the sublimation of ice, the condition for sublimation to occur is to be at a deep cold temperature with low pressure, and the lower the pressure, the faster the ice will sublimate. Therefore, the first step is always to freeze the product, but the freezing temperature usually has to be at least -25^oC to be suitable, so the freezing time of the product will be different when the characteristics of the product are different.

However, many users rarely change this parameter when setting drying for new products or when increasing – decreasing the amount of drying materials such as drying less or drying more. Because of not adjusting the freezing time to suitable, it is possible to encounter the situation where is dry, where is not dry, and the batch is damaged. If you are setting the right time for drying 1/2 of the maximum weight, but at sometime you drying more and forgot to increase the product freezing time, there is a high chance that many products will not dry. The product on the tray has not been properly frozen. Therefore, the dried product will be uneven, not beautiful, the user needs to adjust this parameter, with the new pressure controlled drying program, there is no need to change anything other than the freezing time parameter.

The freezing time of the product also depends on the structural characteristics of each product, the flatter, thinner, and denser, the more the surface in contact with the tray, the faster it will freeze, conversely, the more hollow, rounder or less contact with the tray, the slower the freezing. Therefore, the freezing time will be quite different, users of the freeze dryer need to pay attention to these factor to be able to use them well when they have to dry many types of products and change them more often.

In the near future, it is possible that Mactech will update the new drying program with more optimal control features and don’t need to set the freezing time for the product, so users do not need to change this parameter, but only need to set the freezing temperature for the product, the control software will automatically calculate the appropriate freezing time when drying more or less products. Therefore, please contact Mactech dryer for advice or update the controller, thank you for learn about the shared content.