Freeze-drying device and freeze-drying method

Patent metadata

Field	Value
Publication number	US-12092398-B2
Application number	US-202118569435-A
Country	US
Kind code	B2
Filing date	Jul 12, 2021
Priority date	Jul 12, 2021
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

A freeze-drying apparatus includes a freeze-drying chamber in which an object to be dried using water as a solvent is disposed, a collection chamber provided with a cold trap which connects with the freeze-drying chamber to condense and collect water vapor generated from the object to be dried, measuring devices which measure a state quantity of at least one of the object to be dried, an inside of the freeze-drying chamber, and an inside of the collection chamber, and a determining unit which determines a water vapor mass flow rate based on the state quantity measured by each measuring device, in which the determining unit has measurement models performed to observe the water vapor mass flow rate, and while each measuring device measures the state quantity, a set based on which the water vapor mass flow rate is determined with superiority at the time of the determination is selected.

First claim

The invention claimed is:

1. A freeze-drying apparatus comprising:
a freeze-drying chamber in which an object to be dried using water as a solvent is disposed;
a collection chamber provided with a cold trap which communicates with the freeze-drying chamber to condense and collect water vapor generated from the object to be dried;
a plurality of measuring devices which measure a state quantity of at least one of the object to be dried, an inside of the freeze-drying chamber, and an inside of the collection chamber according to sublimation of the water vapor from the object to be dried; and
a determining unit which determines a water vapor mass flow rate based on the state quantity measured by each measuring device,
wherein the determining unit has a plurality of measurement models performed to observe the water vapor mass flow rate, and while each measuring device measures the state quantity, from among sets obtained by combining a measured value measured by each measuring device and each measurement model corresponding to the measured value, a set based on which the water vapor mass flow rate is determined with superiority at a time of determination is selected, and the water vapor mass flow rate is obtained from this a selected measured value and each measurement model corresponding to the selected measured value.

2. The freeze-drying apparatus according to claim 1 , wherein the state quantity includes a partial pressure of the water vapor, and a measuring device for measuring the partial pressure of water vapor is provided at two or more locations at least one of the freeze-drying chamber and the collection chamber at intervals.

3. The freeze-drying apparatus according to claim 2 , wherein each of the measuring devices for measuring the partial pressure of the water vapor is provided in at least one of the freeze-drying chamber and the collection chamber in a range in which a total pressure is different from each other.

4. The freeze-drying apparatus according to claim 2 , wherein each of the measuring devices for measuring the partial pressure of the water vapor is provided at a predetermined position where a partial pressure difference of 50% or more is generated.

5. The freeze-drying apparatus according to claim 2 , wherein each of the measuring devices for measuring the partial pressure of the water vapor is provided in a region where an initial mass fraction is 1 and the mass fraction decreases thereafter.

6. A freeze-drying method comprising:
a freezing step of disposing an object to be dried using water as a solvent in a freeze-drying chamber and cooling the object to be dried to solidify the solvent from a liquid phase to a solid phase; and
a drying step of sublimating the solidified solvent from the solid phase to a gas phase,
wherein the drying step further includes a step of measuring a state quantity of at least one of the object to be dried, an inside of the freeze-drying chamber, and an inside of the collection chamber according to sublimation of water vapor from the object to be dried using a plurality of measuring devices and determining a water vapor mass flow rate using a determining unit based on the state quantity measured by each measuring device, and
the determining unit has a plurality of measurement models performed to observe the water vapor mass flow rate in advance, and while each measuring device measures the state quantity, from sets obtained by combining a measured value measured by each measuring device and each measurement model corresponding to the measured value, a set based on which the water vapor mass flow rate is determined with superiority at a time of determination is selected, and the water vapor mass flow rate is obtained from a selected measured value and each measurement model corresponding to the selected measured value.

7. The freeze-drying method according to claim 6 , wherein a partial pressure of the water vapor is used as the state quantity, and the partial pressure of the water vapor is obtained by a plurality of measuring devices provided at two or more locations at least one of the freeze-drying chamber and the collection chamber at intervals.

Assignees

• Ulvac Inc

Inventors

• Ozeki Tomomitsu
• Yoshimoto Tsuyoshi
• Ohinata Yoichi

Classifications

• F26B5/044

  for drying materials in a batch operation in an enclosure having a plurality of shelves which may be heated (F26B5/045 takes precedence) · CPC title

• F26B5/06 Primary

  the process involving freezing · CPC title