| 摘要 |
<p>A closed circuit (13) is formed such that the upper ends of preinstalled refrigerant pipes (2A, 2B) in a refrigerant circuit are connected to each other through an upper connecting passage (11) and the lower ends thereof are connected to each other through a lower connecting passage (12). A refrigerant is charged into the closed circuit (13). In a separator (50) of the lower connecting passage (12), a separating heat exchange coil (52) heats the liquid refrigerant to evaporate it, and a filter (53) captures foreign substance from the gas refrigerant. Two conveying heat exchangers (7A, 7B) of the lower connecting passage (12) alternately carry out a repetitive cooling operation of cooling the gas refrigerant, having been changed in phase by the separator (50), to change the phase from gas to liquid and a repetitive pressurizing operation of pressurizing the liquid refrigerant by heating the refrigerant to the extent kept in the liquid phase, respectively, thereby applying a running force to the refrigerant. The refrigerant cleans the preinstalled refrigerant pipes (2A, 2B) in a manner of circulating in the closed circuit (13) from the conveying heat exchangers (7A, 7B). <IMAGE></p> |
