| 摘要 |
PROBLEM TO BE SOLVED: To prevent a fire and to perform cleaning work highly efficiently within a short time without contaminating the circumference by dividing a duct to form a chamber possible to quick-freeze and quick-freezing this chamber to convert the oils-and-fats contaminant or dust bonded to the inner wall of the duct to frozen dust and breaking this dust to peel and remove the same. SOLUTION: At a time of work, a cleaning opening 27 is preformed to a duct 22. At first, high pressure air is introduced into the duct from an air gun 15 to expand respective air bags 16a-16d to form partition walls in the duct 22 to form a chamber 22 possible to quick-freeze. Next, freezing gas is ejected into the chamber 22 from the leading end ejection nozzle 28 of a freezing machinery to quick freeze the oils and fats contaminant or dust bonded to and deposited on the inner surface of the chamber 22 to form frozen dust. Succeedingly, the frozen dust is broken and peeled by the air scraper held by the hand of a worker whose head is introduced into the duct from the cleaning opening 27. Thereafter, the leading end of the dust collecting hose of a dust collector is positioned in the duct 22 to suck and remove the broken and peeled frozen dust 23. |
