Patent attributes
A freeze-drying device includes a controller configured to control depressurization of containers filled with a liquid including a raw material and a medium to freeze the liquid from a liquid surface. The freeze-drying device also includes a gas capture pump configured to exhaust a freeze-drying chamber accommodating the containers, and a positive-displacement pump configured to discharge gas from a space accommodating the gas capture pump. The controller executes an exhaust mitigation process that performs the depressurization at an exhaust capability that is less than a rated exhaust capability of the freeze-drying device. The controller uses a partial pressure value of the medium to determine when the exhaust mitigation process ends. The controller maintains an exhaust speed of the gas capture pump and decreases an exhaust speed of the positive-displacement pump in the exhaust mitigation process.