The vacuum pump should be selected according to the vacuum requirements, pumping rate requirements and material characteristics of the freeze dryer. Different types of vacuum pumps have different ultimate vacuum degrees. For example, the ultimate vacuum degree of a rotary vane vacuum pump can generally reach 10⁻² - 10⁻³Pa, which is suitable for small freeze dryers that do not require particularly high vacuum degrees; the ultimate vacuum degree of a Roots vacuum pump can reach 10⁻³ - 10⁻⁴Pa, and it is often combined with a rotary vane vacuum pump and other units for occasions with high requirements for vacuum and pumping rates. The pumping rate of the vacuum pump should be considered, and the pumping rate should be able to meet the requirements of pumping the drying chamber from atmospheric pressure to the set vacuum degree within the specified time. For example, if the freeze drying chamber needs to be pumped from atmospheric pressure to 15Pa within half an hour, a vacuum pump with a suitable pumping rate needs to be selected. For freeze drying of materials containing corrosive gases or more water vapor, a vacuum pump that is corrosion-resistant and can handle a large amount of water vapor should be selected. For example, a vacuum pump with a gas ballast device can effectively handle water vapor and prevent condensation in the pump. At the same time, factors such as the operating stability, maintenance cost, and noise of the vacuum pump also need to be considered. Technical support for Jipu freeze dryer.
