Refrigeration – Processes – Assembling – charging – or repairing of refrigeration producer
Reexamination Certificate
2000-03-10
2001-08-28
Tapolcai, William E. (Department: 3744)
Refrigeration
Processes
Assembling, charging, or repairing of refrigeration producer
C062S303000
Reexamination Certificate
active
06279330
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a piping cleaning system and a piping cleaning method for refrigeration units including air conditioners and refrigerators.
BACKGROUND ART
In renewal demands of various types of air conditioners, existing refrigerant piping is often re-used as it is. In such a case, if a refrigerant for the existing refrigerant circuit and a refrigerant for a new refrigerant circuit are the same CFC (chlorofluorocarbon) or HCFC (hydrochlorofluorocarbon) refrigerant, the existing refrigerant piping can be used without causing any significant problems.
However, from the recent years' environmental point of view or the like, it has been proposed to use HFC (hydrofluorocarbon) refrigerants instead of conventional CFC or HCFC refrigerants.
In this case, for reuse of the existing refrigerant piping, it is necessary to clean the interior of the refrigerant piping. That is, it is often the case that lubricating oil have been deposited on or contaminants or the like have stuck to the interior surfaces of the existing refrigerant piping. In particular, whereas mineral oil has been used lubricating oil for conventional CFC refrigerants and the like, synthetic oil is used as lubricating oil for HFC refrigerants. This causes a problem that mineral oil, if remaining in the existing refrigerant piping, would cause contaminations to occur to a newly provided refrigerant circuit, with the result that the throttle mechanism may be blocked or that the compressor may be damaged.
DISCLOSURE OF THE INVENTION
Therefore, an object of the present invention is to provide a piping cleaning system and a piping cleaning method for refrigeration units capable of cleaning the refrigerant piping with good efficiency.
In order to achieve the above object, the present invention provides a piping cleaning system for refrigeration units, comprising:
a cleaning circuit for cleaning refrigerant piping by circulating a refrigerant therethrough;
refrigerant amount detecting means for detecting an amount of refrigerant with which the refrigerant piping is cleaned; and
adjusting means for adjusting cleaning refrigerant amount based on the amount of refrigerant detected by the refrigerant amount detecting means.
In this invention, the refrigerant piping is cleaned by circulating the refrigerant through the cleaning circuit. In this process, the amount of refrigerant with which the refrigerant piping is cleaned is detected by the refrigerant amount detecting means and, based on the detected amount of refrigerant, the cleaning refrigerant amount is adjusted by the adjusting means. Therefore, according to this invention, any excess or shortage of the refrigerant with which the refrigerant piping is cleaned can be eliminated, and so the refrigerant piping can be cleaned efficiently. A short amount of the cleaning refrigerant would cause the cleaning performance to lower, while an excessive amount of the cleaning refrigerant would lead to a less smooth circulation of the refrigerant.
Also, a piping cleaning system for refrigeration units according to one embodiment further comprises a transfer heat exchanger provided halfway on the cleaning circuit; and
a heat pump to cause the transfer heat exchanger to alternately iterate a sucking operation by cooling a gas refrigerant within the transfer heat exchanger to effectuate depressurization thereof so that a refrigerant is sucked in from outside thereto, and a discharge operation by heating the refrigerant within the transfer heat exchanger to effectuate pressurization thereof so that a liquid refrigerant is discharged therefrom, for circulating a liquid refrigerant through the refrigerant piping by the transfer heat exchanger.
In this piping cleaning system, the transfer heat exchanger performs a heat pump action of alternately iterating the sucking operation by cooling a gas refrigerant within the transfer heat exchanger to effectuate depressurization thereof so that a refrigerant is sucked in from outside thereto, and the discharge operation by heating the refrigerant within the transfer heat exchanger to effectuate pressurization thereof so that a liquid refrigerant is discharged therefrom.
According to such a heat pump action, there is no need of circulating the refrigerant in the cleaning circuit by a compressor, and therefore the fear that foreign matters from the compressor may mix into the refrigerant piping can be eliminated.
Also, a piping cleaning system of another embodiment comprises two transfer heat exchangers provided halfway on the cleaning circuit and connected in parallel to each other; and
a heat pump to cause the transfer exchangers to alternately iterate a sucking operation by cooling a gas refrigerant within the transfer heat exchangers to effectuate depressurization thereof so that a refrigerant is sucked in from outside thereto, and a discharge operation by heating the refrigerant within the transfer heat exchangers to effectuate pressurization thereof so that a liquid refrigerant is discharged therefrom, for circulating a liquid refrigerant through the refrigerant piping by the transfer heat exchangers.
In this piping cleaning system, the two transfer heat exchangers perform a heat pump action of alternately iterating the sucking operation by cooling a gas refrigerant within the transfer heat exchangers to effectuate depressurization thereof so that a refrigerant is sucked in from outside thereto, and the discharge operation by heating the refrigerant within the transfer heat exchangers to effectuate pressurization thereof so that a liquid refrigerant is discharged therefrom.
According to such a heat pump action, there is no need of circulating the refrigerant in the cleaning circuit by a compressor, and therefore the fear that foreign matters from the compressor may mix into the refrigerant piping can be eliminated.
Also, in one embodiment, the adjusting means of the cleaning refrigerant amount is implemented by
at least one of a refrigerant resupply line connected to the transfer heat exchanger and serving for resupplying the refrigerant to the cleaning circuit and a refrigerant bleed line connected to the transfer heat exchanger and serving for taking out the refrigerant from the cleaning circuit.
In this piping cleaning system, when the cleaning refrigerant in the cleaning circuit runs short, the cleaning refrigerant can be supplied to the transfer heat exchanger through the refrigerant resupply line and the cleaning refrigerant can be heated by this transfer heat exchanger, so that the cleaning refrigerant can be resupplied to the cleaning circuit efficiently. Also, when the cleaning refrigerant in the cleaning circuit is excessive, excess refrigerant accumulated in the transfer heat exchanger can be bled efficiently by the refrigerant bleed line. Thus, the amount of cleaning refrigerant can be maintained normally at an appropriate level, and the refrigerant piping can be cleaned efficiently.
Also, in another embodiment, separating means for separating foreign matters from the refrigerant is connected to the cleaning circuit, and
the refrigerant amount detecting means is implemented by a refrigerant level sensor provided on the separating means.
In this piping cleaning system, the cleaning performance by the cleaning refrigerant can be maintained by separating foreign matters from the cleaning refrigerant by means of the separating means, and besides the amount of cleaning refrigerant can be detected by the refrigerant level sensors provided on the separating means.
Also, in one embodiment, the heat pump has a throttle mechanism connected between the two transfer heat exchangers, a compressor and a four-way switching valve, and also has a heat pump circuit other than the cleaning circuit through which the cleaning refrigerant flows, wherein a flowing direction of working refrigerant flowing through the heat pump circuit is switched over by switching over the four-way switching valve, by which the sucking operation and the discharge operation of the two transfer heat exchangers are switched over;
the piping cl
Iijima Toshihiro
Takegami Masaaki
Ueno Takeo
Daikin Industries Ltd.
Tapolcai William E.
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