Pipes and tubular conduits – Combined – With end structure
Reexamination Certificate
1998-03-09
2001-05-15
Stryjewski, William (Department: 3765)
Pipes and tubular conduits
Combined
With end structure
C285S288110, C285S289500
Reexamination Certificate
active
06230747
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a piping structure and in particular relates to the structure of a joint portion between pipes.
As one of conventional refrigerating apparatus, there has been known a multi-type air conditioner as disclosed in Japanese Patent Application Laid-Open Gazette No. 4-208370, in which a plurality of indoor units are connected to a single outdoor unit. In this air conditioner, a refrigerant circuit of the outdoor unit is connected to a refrigerant circuit of each of the indoor units through a connection pipe thereby forming a refrigerant piping system.
For the above-mentioned air conditioner, the outdoor unit and the indoor units are shipped from production facilities, are carried to the site of installation in a building or the like, are installed and are then connected to the connection pipe.
The connection pipe is formed in a way of brazing both pipes which each have a specific length and are each made of a copper pipe with each other. At the time, nitrogen is poured into the connection pipe to remove air out of the connection pipe so that air in the connection pipe is wholly displaced by nitrogen, and thereafter both the pipes are brazed.
Problems to be Solved
Each pipe of the air conditioner is formed, for example, in a uniform diameter from one opening end to another opening end and as mentioned above, the connection pipe is formed by brazing the pipes.
Meanwhile, in pipe connecting work, some general rules must be strictly observed. The general rules include “clean rule” and “dry rule”. The dry rule is a rule that makes pipe connecting work so as not to leave water in the pipe. The clean rule is a rule that makes pipe connecting work so as to prevent the entry of alien substances into the pipe.
However, in conventional pipe connecting work, sufficient parts management is not necessarily made. For example, water drops due to dew fall or the like are often left on the inner surface of an original pipe for pipe connecting work. In other words, the pipe is often stored with both opening ends open.
Therefore, the pipe causing dew fall may be used as it is. Further, air in the pipe includes moisture. Accordingly, water may be left in the pipe contrary to the dry rule when refrigerant is charged into the pipe. This causes a problem of lack of reliability of air conditioning.
Furthermore, when the pipe is heated by a burner or the like in brazing, air in the pipe may produce an oxide film on the surface of the pipe made of a copper pipe.
Such a phenomenon is contrary to the clean rule. In detail, when refrigerant is charged into the pipe, the refrigerant peels off the oxide film. The peeled oxide film may blockade a narrow space such as a capillary tube or may pollute a lubricating oil for refrigerating apparatus thereby degrading lubricating performance. This may cause a problem leading to breakage of equipment.
The present invention has been made in view of the foregoing problems and therefore has an object of enabling strict observation of both the clean rule and the dry rule in pipe connecting work thereby enhancing the reliability of air conditioning.
SUMMARY OF THE INVENTION
To attain the above object, a measure taken in the present invention is to blockade both opening ends of a pipe with metallic films respectively.
Specific Features of the Invention
More specifically, a pipe connecting method as a first aspect of the invention first comprises a blockading step of fitting a block plug (
50
) made of a film of brazing material to an opening end of a connecting portion (
42
) continuously located on at least one end side of a main portion (
41
) of a pipe (
40
) formed in a specific length in a way that the outer periphery of the block plug (
50
) adheres closely to the opening end of the connecting portion (
42
) thereby defining the inside and outside of the pipe (
40
).
The above method further comprises a piece inserting step of inserting one end of a connecting piece (
60
) into the connecting portion (
42
) of the pipe (
40
) in a way of breaking through the block plug (
50
) and inserting the other end of the connecting pipe (
60
) into the connecting portion (
42
) of another pipe (
40
) in a way of breaking through another block plug (
50
), thereby leaving each of the block plugs (
50
) between the connecting portion (
42
) of each of the pipes (
40
) and the connecting piece (
60
).
The above method still further comprises a joint step of externally heating the connecting portions (
42
) of the pipes (
40
) into which the connecting piece (
60
) is inserted to melt the block plugs (
50
) thereby jointing the connecting portions (
42
) of the pipes (
40
) with the connecting piece (
60
) through the block plugs (
50
).
A pipe connecting method as a second aspect of the invention comprises a blockading step of fitting a block plug (
50
) made of a film of brazing material to a connecting portion (
42
) continuously located on at least one end side of a main portion (
41
) of a pipe (
40
) formed in a specific length in a way that the outer periphery of the block plug (
50
) adheres closely to the connecting portion (
42
) thereby defining the inside and outside of the pipe (
40
).
The above method further comprises an inserting step of inserting the connecting portion (
42
) of another pipe (
40
) into the connecting portion (
42
) of the former pipe (
40
) to contact the block plug (
50
) fitted to the former pipe (
40
) with an end of the latter pipe (
40
).
The above method still further comprises a joint step of externally heating the connecting portion (
42
) of the former pipe (
40
) to melt the block plug (
50
) thereby jointing both the connecting portions (
42
) of the pipes (
40
) through the block plug (
50
).
A pipe connecting method as a third aspect of the invention comprises a blockading step of forming an end piece (
43
) including joint portions (
44
,
44
) located at respective ends and a bagged portion (
45
) larger in diameter than the joint portions (
44
,
44
), fitting a block plug (
50
) formed of a metallic film to the bagged portion (
45
) of the end piece(
43
) in a way that the outer periphery of the block plug (
50
) adheres closely to the inner periphery of the bagged portion (
45
), and fitting one of the joint portions (
44
) of the end piece (
43
) to an end of the main portion (
41
) of the pipe (
40
) thereby forming connecting portions (
42
) at both ends of the pipe (
40
) respectively.
The above method further comprises a piece inserting step of inserting a connecting piece (
60
) into the end piece (
43
) in a way of breaking more than a half of the outer peripheral edge of the block plug (
50
) thereby leaving the block plug (
50
) between the bagged portion (
45
) and the connecting piece (
60
).
The above method still further comprises a joint step of brazing the connecting piece (
60
) and the joint portion (
44
) of the end piece (
43
) with each other.
In the above pipe connecting methods, the connecting portions (
42
) of the pipe (
40
) may be formed at both ends of the main portion (
41
) of the pipe (
40
) in a way to be continuous with the ends of the main portion (
41
), respectively. Both the connecting portions (
42
) may each have the block plug (
50
) so that the inside of the pipe (
40
) is enclosed.
In the pipe connecting method of the invention, the connecting portions (
42
) of the pipe (
40
) may be formed at both ends of the main portion (
41
) of the pipe (
40
) in a way to be continuous with the ends of the main portion (
41
), respectively, one of the connecting portions (
42
) may be formed into a large-diameter connecting portion larger in diameter than the main portion (
41
), the other connecting portion (
42
) may be formed into a small-diameter connecting portion identical in diameter with the main portion (
41
), and the small-diameter connecting portion (
42
) of the pipe (
40
) may be inserted into the large-diameter connecting portion (
42
) of another pipe (
40
) and both the connecting portions (
42
,
42
) may be then jointed.
In the pipe c
Nakao Noriaki
Nishino Haruhiko
Daikin Industries Ltd.
Nixon & Peabody LLP
Stryjewski William
Studebaker Donald R.
LandOfFree
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