Refrigeration – Processes – Assembling – charging – or repairing of refrigeration producer
Reexamination Certificate
1999-09-30
2001-11-27
Bennett, Henry (Department: 3744)
Refrigeration
Processes
Assembling, charging, or repairing of refrigeration producer
C062S149000, C062S474000, C062S475000
Reexamination Certificate
active
06321542
ABSTRACT:
TECHNICAL FIELD
This invention relates to a method for cleaning a pipe for a refrigerating apparatus and a pipe cleaning apparatus for a refrigerating apparatus, and particularly relates to measures for cleaning preinstalled refrigerant pipes.
BACKGROUND ART
There are known a large number of conventional air conditioners serving as refrigerating apparatuses. An example of such conventional air conditioners is formed such that a compressor, a four-way selector valve, an outdoor heat exchanger, a motor-operated expansion valve, a receiver and an indoor heat exchanger are connected in this order through refrigerant pipes, as disclosed in Japanese Patent Application Laid-Open Gazette No. 8-100944. This air conditioner is designed for cooling and heating operations.
<Problems to be Solved>
In renewing various kinds of air conditioners including the above-mentioned air conditioner, preinstalled refrigerant pipes are sometimes used while being left in place. In such cases, if a refrigerant in a preinstalled refrigerant circuit and a refrigerant in a newly installed refrigerant circuit are the same CFC (chlorofluorocarbon) or HCFC (hydrochlorofluorocarbon) refrigerants, the preinstalled refrigerant pipes can be used for the new refrigerant circuit without causing so much of a problem.
For newly installed refrigerant circuits, however, a HFC (hydrofluorocarbon) refrigerant for example is proposed to be substituted for the conventional CFC or HCFC refrigerant in consideration of recent environmental problems and the like.
In this case, in order that the preinstalled refrigerant pipes are used for a new refrigerant circuit while being left in place, the insides of the refrigerant pipes must be cleaned. Specifically, lubricating oil or contaminants often deposit on the inner surfaces of the preinstalled refrigerant pipes. In particular, though mineral oil is used as lubricating oil for the conventional CFC refrigerant or the like, synthetic oil is used as lubricating oil for the HFC refrigerant. Accordingly, if the mineral-type lubricating oil is left in the preinstalled refrigerant pipe, foreign substance (contamination) will occur in the newly installed refrigerant circuit. Such foreign substance may cause problems such as closure of a throttling mechanism and damage to a compressor (
41
).
However, any technique for cleaning the preinstalled refrigerant pipes has not yet been proposed. Therefore, there is a demand for developing a new cleaning means for cleaning the preinstalled refrigerant pipes when the preinstalled refrigerant pipes are used for a new refrigerant circuit while being left in place.
The present invention has been made in view of the above point, and has its object of providing a new pipe cleaning method and a new pipe cleaning apparatus for a preinstalled refrigerant circuit in the case of using preinstalled refrigerant pipes for a new refrigerant circuit while leaving them in place.
DISCLOSURE OF INVENTION
In this invention, a closed circuit (
13
) is formed such that the upper ends of preinstalled refrigerant pipes (
2
A,
2
B) 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 (
7
A,
7
B) 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 giving a running force to the refrigerant. The refrigerant cleans the preinstalled refrigerant pipes (
2
A,
2
B) by circulating through the closed circuit (
13
) from the conveying heat exchangers (
7
A,
7
B).
<Solutions>
Specifically, as shown in
FIG. 1
, a first solution taken in the present invention is directed to a pipe cleaning method for a refrigerating apparatus in which refrigerant pipes (
2
A,
2
B) in a refrigerant circuit is cleaned.
The method includes a first step of forming a single closed circuit (
13
) by a connecting passage (
12
) for cleaning and the refrigerant pipes (
2
A,
2
B) in the refrigerant circuit by connecting the connecting passage (
12
) to at least one ends of the refrigerant pipes (
2
A,
2
B) and charging a refrigerant into the closed circuit (
13
).
Further, the method includes a second step of cleaning the refrigerant pipes (
2
A,
2
B) by circulating the refrigerant in the closed circuit (
13
) so that the refrigerant in the liquid phase flows through the refrigerant pipes (
2
A,
2
B) by means of conveying means (
40
) provided in the connecting passage (
12
).
In addition, the method includes, after the cleaning step, a third step of detaching the connecting passage (
12
) from the refrigerant pipes (
2
A,
2
B).
In a second solution of the present invention, the first solution is adapted such that the second step includes circulating the refrigerant in the closed circuit (
13
) and concurrently separating foreign substance from the refrigerant by separating means (
50
).
In a third solution of the present invention, the second solution is adapted such that the second step includes heating a liquid refrigerant by the separating means (
50
) during the passage of the refrigerant through the connecting passage (
12
) to change the phase thereof from liquid to gas thereby separating foreign substance from the refrigerant, cooling the gas refrigerant to change the phase thereof from gas to liquid again, and then delivering the liquid refrigerant to the refrigerant pipes (
2
A,
2
B) by the conveying means (
40
).
In a fourth solution of the present invention, the second solution is adapted such that the second step includes: a first separating operation of heating the liquid refrigerant by the separating means (
50
) during the passage thereof through the connecting passage (
12
) to change the phase thereof from liquid to gas thereby separating foreign substance from the refrigerant; a second separating operation of capturing the foreign substance from the gas refrigerant; cooling the gas refrigerant to change the phase thereof from gas to liquid again; and then delivering the liquid refrigerant to the refrigerant pipes (
2
A,
2
B) by the conveying means (
40
).
In a fifth solution of the present invention, the third or fourth solution is adapted such that the conveying means (
40
) in the second step performs a cooling operation of cooling the gas refrigerant, having been changed in phase by the separating means (
50
), to change the phase thereof from gas to liquid again and a conveying operation of delivering the liquid refrigerant to the refrigerant pipes (
2
A,
2
B).
In a sixth solution of the present invention, the fifth solution is adapted such that the conveying means (
40
) includes two conveying heat exchangers (
7
A,
7
B) each provided at some midpoint of the connecting passage (
12
) and connected in parallel with each other, and the two conveying heat exchangers (
7
A,
7
B) alternately carry out a repetitive cooling operation of cooling the gas refrigerant, having been changed in phase by the separating means (
50
), to change the phase thereof 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, so that the pressurizing operation causes the liquid refrigerant to be delivered to the refrigerant pipes (
2
A,
2
B).
In a seventh solution of the present invention, the first solution is adapted such that the second step includes circulating the refrigerant from the conveyi
Iijima Toshihiro
Takegami Masaaki
Ueno Takeo
Yamamoto Masaki
Bennett Henry
Daikin Industries Ltd.
Jiang Chen-Wen
Nixon & Peabody LLP
Studebaker Donald R.
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