Method and apparatus for regeneration water

• US 20070125112A1
• Filed: 11/25/2004
• Published: 06/07/2007
• Est. Priority Date: 11/28/2003
• Status: Active Grant

• Current Assignee: Sumitomo Heavy Industries Limited
• Original Assignee: Sumitomo Heavy Industries Limited
• Inventors: Tsuyuki, Ryosuke
• Granted Patent: US 7,997,089 B2
• Time in Patent Office: Days
• US Class Current: 62/272
• CPC Class Codes: F04B 37/08 by condensing or freezing, e.g. cryogenic pumps
• CPC Class Codes: Y10S 417/901 Cryogenic pumps

Abstract

Ice condensed in a portion in a case in which a cryogenic refrigerator is installed, which is cooled by the cryogenic refrigerator, is melted by increasing a temperature of the ice to a melting point of the ice or higher. Then, while the temperature of the melted ice and a pressure thereof are kept to be equal to or higher than a freezing point of water, the pressure is reduced by rough evacuation so as to vaporize water. At a time at which the water is discharged, the pressure is further reduced so as to discharge water vapor. In this manner, regeneration of water is performed in accordance with a state of the water (i.e., a solid state, a liquid state, and a gas state), thereby shortening a regeneration time.

Claims

1. A water regeneration method for discharging ice condensed in a portion cooled by a cryogenic refrigerator installed in a case to an outside of the case, comprising:

a temperature increasing step for melting the ice;

a vaporizing step for vaporizing water; and

a discharging step for discharging water vapor, wherein the ice, the water, and the water vapor are regenerate in stages.

2. The water regeneration method according to claim 1, wherein each of the vaporizing step and the discharging step includes buildup determination.

3. The water regeneration method according to claim 1, wherein the temperature increasing step is a warm-up step for increasing a temperature of the portion of the case in which the ice is condensed to a melting point of the ice or higher to melt the ice.

4. The water regeneration method according to claim 1, wherein the temperature increasing step is performed by one or more of temperature increase by a reverse rotation in which a motor of the refrigerator is rotated in an opposite direction to a rotation direction during cooling, temperature increase by purge in which a purge gas having a higher temperature than the melting point of the ice is made to flow in the case to return a pressure in the case that is kept vacuum to an atmospheric pressure and improve thermal conductivity with the outside of the case, and temperature increase by a heater.

5. The water regeneration method according to claim 1, wherein, in the vaporizing step, water is vaporized by performing rough evacuation to reduce a pressure of the portion in which the water generated from melting of the ice by the temperature increasing step is accumulated within a range in which the temperature and the pressure of the portion are prevented from reaching a freezing point of the water, the buildup determination for determining pressure increase by discharged moisture or a gas when the evacuation is stopped is performed, and the water vaporization and the buildup determination are repeated until the water vanishes away.

6. The water regeneration method according to claim 5, wherein the pressure during the rough evacuation is set to 100 Pa to 200 Pa.

7. The water regeneration method according to claim 1, wherein the discharging step is an evacuation step for discharging the water vapor by further reducing the pressure by the rough evacuation at a time when the water is vaporized by the vaporizing step, performing the buildup determination to determine the pressure increase by a gas when the evacuation is stopped, and repeating the discharge of the water vapor and the buildup determination until the pressure increase is smaller than a value used for the determination.

8. The water regeneration method according to claim 1, wherein the temperature increasing step is switched to the vaporizing step at a time when the temperature of the portion of the case in which the ice is condensed reaches the melting point of the ice.

9. The water regeneration method according to claim 5 wherein the vaporizing step is switched to the evacuation step based on the buildup determination using the discharged moisture or gas when the evacuation is stopped.

10. A water regeneration apparatus for discharging ice condensed in a portion cooled by a cryogenic refrigerator installed in a case to an outside of the case, comprising:

temperature increasing means for increasing a temperature of the portion in the case in which the ice is condensed to a melting point of the ice or higher to melt the ice;

vaporizing means for vaporizing water generated by melting of the ice by performing rough evacuation to reduce a pressure of the portion in which the water is accumulated within a range in which the temperature and the pressure of the portion are prevented from reaching a freezing point of the water, performing buildup determination based on discharged moisture or gas when the evacuation is stopped, and repeating the water vaporization and the buildup determination until the water vanishes away; and

evacuation means for discharging water vapor by further reducing the pressure at a time when the water is vaporized.

11. The water regeneration apparatus according to claim 10, wherein the temperature increasing means is achieved by one or more of a reverse rotation of a motor of the refrigerator, a purge gas, and a heater.

12. A cryopump comprising the water regeneration apparatus according to claim 10.

13. A water trap comprising the water regeneration apparatus according to claim 10.