Blast celaning method and method and device for producing solid carbon dioxide to be used for the same

Abstract

The present invention provides a blast cleaning method with cleaning performance adjustable by changing the hardness, shape and size of solid carbon dioxide to be used as a shot material, and a method and a device for producing solid carbon dioxide to be used for the blast cleaning method. The blast cleaning method includes the steps of: forming plate-shaped solid carbon dioxide, crushed pieces of which are used as a shot material (Step S 10 ), transporting the formed plate-shaped solid carbon dioxide to a site of work (Step S 20 ), crushing the plate-shaped carbon dioxide at the site of work, etc. (Step S 30 ), putting the crushed pieces into a cleaning device (blasting machine) (Step S 40 ), and cleaning an object to be cleaned by blowing the crushed pieces to the object to be cleaned (Step S 50 ).

1 . A blast cleaning method in which a shot material is blown to an object to be cleaned at a high speed to separate extraneous matter, comprising the steps of: forming plate-shaped solid carbon dioxide ( 7 ) by cooling liquid carbon dioxide ( 2 ) while applying a pressure higher than the pressure of the triple point thereto; crushing the plate-shaped solid carbon dioxide ( 7 ); and cleaning an object to be cleaned by using the crushed solid carbon dioxide ( 7 ) as a shot material. 
     
     
         2 . The blast cleaning method according to  claim 1 , wherein the thickness of the plate-shaped solid carbon dioxide ( 7 ) is 3 to 8 millimeters. 
     
     
         3 . A method for producing solid carbon dioxide ( 7 ) to be used as a shot material in the blast cleaning method according to  claim 1  or  2 , comprising: a first cooling step of cooling liquid carbon dioxide ( 2 ) to a sublimation temperature at the atmospheric pressure from a temperature higher than the temperature of the triple point while applying a pressure higher than the pressure of the triple point thereto; and a second cooling step of cooling the solid carbon dioxide ( 7 ) formed in the first cooling step to a temperature lower than the sublimation temperature. 
     
     
         4 . A device for producing solid carbon dioxide ( 7 ) to be used as a shot material in the blast cleaning method according to  claim 1  or  2 , comprising: a rectangular tabular hollow part ( 4 ) formed to become capable of being filled with liquid carbon dioxide ( 2 ); a cooling jacket ( 5 ) formed so as to surround this hollow part ( 4 ); a vacuum heat insulating chamber ( 6 ) formed so as to surround the cooling jacket( 5 ); a vacuum pump ( 20 ) for vacuuming the vacuum heat insulating chamber ( 6 ) and the hollow part ( 4 ); a liquid carbon dioxide supply means ( 3 ) for supplying the liquid carbon dioxide ( 2 ) into the hollow part ( 4 ) through a first supply pipe ( 9   a ); a refrigerating machine to be connected to the cooling jacket ( 5 ) via a second supply pipe ( 11 ); a first on-off valve ( 13   a ) installed in the first supply pipe ( 9   a ); and a second on-off valve ( 8   b ) installed in the second supply pipe, wherein the hollow part ( 4 ), the cooling jacket ( 5 ), and the vacuum heat insulating chamber ( 6 ) form a vacuum container ( 1 ) with a triplex structure.