Patent ID: 6321542
Filing Date: 2001-11-27
Classification: B08B,F25B,F28G

Abstract:
A pipe cleaning method for a refrigerant apparatus in which refrigerant pipes (2A,2B) in a refrigerant circuit is cleaned, the method comprises:a first step of forming a single closed circuit (13) by connecting a connecting passage (12) for cleaning to at least one end of each of the refrigerant pipes (2A,2B) and charging a refrigerant into the closed circuit (13);a second step of cleaning the refrigerant pipes (2A,2B) by circulating the refrigerant in the closed circuit (13) so that the refrigerant in liquid phase flows through the refrigerant pipes (2A,2B) by means of conveying means (40) provided in the connecting passage (12) and separating a foreign substance from the refrigerant using separating means (50); anda third step of after the cleaning step, detaching the connecting passage (12) from the refrigerant pipes (2A,2B),whereinthe second step includes: heating the refrigerant in liquid phase using the separating means (50) during passage of the refrigerant through the connecting passage (12) to change the phase of the refrigerant from liquid to gas thereby to separate the foreign substance from the refrigerant; subsequently cooing the refrigerant in gas phase to change the phase of the refrigerant from gas to liquid; and delivering the refrigerant in liquid phase to the refrigerant pipes (2A,2B) using the conveying means (40), andthe conveying means (40) includes two conveying heat exchangers (7A,7B) each provided at some midpoint of the connecting passage (12) and connected in parallel with each other, the two conveying heat exchangers (7A,7B) alternating a cooling operation of cooling the refrigerant of which phase is changed to gas by the separating means (50) to change the phase of the refrigerant from gas to liquid, and a pressurizing operation of heating and pressurizing the refrigerant in liquid phase to deliver the refrigerant in liquid phase to the refrigerant pipes (2A,2B).