REFRIGERANT CHARGING SYSTEM IN WHICH A REFRIGERANT IS FRESHENED AND SMOOTHLY CHARGED INTO A STORAGE CONTAINER

Abstract: For carrying out charge of a refrigerant into a storage container (26), the refrigerant is separated into a gaseous phase and a liquid phase refrigerant segment supplied to a receiving unit (22) and an evaporator (18), respectively, which are thermally coupled to each other. The gaseous phase refrigerant segment is modified into a modified refrigerant of a liquid phase in the receiving unit by use of evaporation of the liquid phase refrigerant segment in the evaporator. The modified refrigerant is sent from the receiving unit to the storage container. For smoothly carrying out reception of the modified refrigerant, the storage container has an inner pressure which is controlled by a controlling arrangement (31, 32, 33, 34).

Description: This invention relates to a refrigerant charging apparatus which is used for charging a refrigerant into a storage container. More particularly, this invention relates to an apparatus which is operable in a self-heat exchanging system. A refrigerant, such as a fluorocarbon refrigerant, is commonly employed in an air conditioner of an automobile or a refrigerator. A refrigeration system will operate more efficiently when the refrigerant is pure and relatively free of pollutants, for example, oil, air and water. However, a used refrigerant is contaminated by such pollutants. Therefore, it is necessary to periodically remove and recharge the refrigerant within the refrigerant system. Various refrigerant recovery and purification systems are already known, as e.g. from US-A-4,768,347, which is acknowledged in the preamble of claim 1. In the manner which will later be described in connection with this invention, such a refrigerant charging apparatus comprises a receiving unit which receives an object refrigerant to make a modifier refrigerant of a liquid phase by use of an evaporator included in an external freezing or refrigeration circuit. The external freezing circuit is operated to cause evaporation of another refrigerant in the evaporator. The object refrigerant is produced from an original refrigerant which is employed in, for example, an air conditioning system. The modified refrigerant is dropped from the receiving unit into a storage container by gravitational force. However, it is difficult to employ the external freezing circuit for modifying the object refrigerant. In action, the storage container has an inner pressure which increases in response to the increase of the modified refrigerant in the storage container. As a result, it may occur that the modified refrigerant is not charged to the storage container. It is therefore an object of the present invention to provide a refrigerant charging apparatus for processing an object refrigerant more efficiently. It is another object of this invention to provide an apparatus of the type described, in which it is unnecessary to make the object refrigerant pass repeatedly through filter dryers. It is still another object of this invention to provide an apparatus of the type described, in which the refrigerant is purified and smoothly charged into a storage container. According to this invention this is accomplished by the apparatus indicated in claim 1. Additional features are cited in the dependent claims. Fig. 1 is a block diagram of a refrigerant charging apparatus according to a first embodiment of this invention; and Fig. 2 is a block diagram of a refrigerant charging apparatus according to a second embodiment of this invention. Referring to Fig. 1, a refrigerant charging apparatus according to a first embodiment of this invention is for charging into a storage container 26 an original refrigerant recovered from an object refrigeration circuit (not shown) which is used in, for example, an air conditioning system of an automobile. Generally, the original refrigerant consists of, for example, fluorocarbon refrigerants. The refrigerant charging apparatus comprises an inlet pipe 11 for recovering the original refrigerant from the object refrigeration circuit in the manner known in the art. For recovering the original refrigerant, the inlet pipe 11 is connected to the object refrigeration circuit. Thus the original refrigerant may be supplied to a compressor 13 through the inlet pipe 11. In this event, the original refrigerant is of gaseous phase. The inlet pipe 11 can be disconnected from the object refrigeration circuit. The inlet pipe 11 will be referred to as an introducing arrangement. The original refrigerant is compressed in the compressor 13 and then is supplied as a compressed refrigerant to a condenser 14 which is connected to the compressor 13 through a pipe 12. In the condenser 14, the compressed refrigerant is cooled to thereby be condensed as a condensed refrigerant. The condensed refrigerant is supplied to a filter dryer 15 through a pipe which is similar to the pipe 12. The filter dryer 15 is for removing an impurity, moisture, and acid content from the condensed refrigerant in the manner known in the art. After that, the condensed refrigerant is supplied to a vessel 16 through a pipe which is similar to the pipe 12. The condensed refrigerant is separated into a liquid phase and a gaseous phase refrigerant component in the vessel 16. As well known in the art, the gaseous phase refrigerant component has a higher purity than that of the liquid phase refrigerant component. A combination of the compressor 13, the condenser 14, the filter dryer 15, and the vessel 16 is referred to as a processing arrangement. The vessel 16 has a first outlet port 16a at a bottom portion thereof and a second outlet port 16b at an upper portion thereof. The first outlet port 16a is connected to an evaporator 18 through an automatic expansion valve 19 and a first supplying pipe 21. Therefore, the liquid phase refrigerant component is sent as a cooling refrigerant from the vessel 16 to the evaporator 18 and is evaporated in the evaporator 18 to carry out cooling of a surrounding area of the evaporator 18 in the manner known in the art. On the other hand, the second outlet port 16b is connected to a receiving unit 22 through a second supplying pipe 23 to communicate with a hollow space which is defined by the receiving unit 22. Therefore, the gaseous phase refrigerant component is sent as an object refrigerant from the vessel 16 to the receiving unit 22. The evaporator 18 is thermally coupled to the receiving unit 22. In this embodiment, the evaporator 18 is contained in the receiving unit 22. As a result, the gaseous phase refrigerant component is cooled in the receiving unit 22 by evaporation of the cooling refrigerant, namely, the liquid phase refrigerant component in the evaporator 18. In other words, heat exchange is carried out between the gaseous and the liquid phase refrigerant components. Therefore, the evaporator 18 may be referred to as a cooling arrangement. After being evaporated in the evaporator 18, the cooling refrigerant is returned to the compressor 13 through a returning pipe 24. A temperature detecting unit 25 is thermally coupled to the returning pipe 24. The temperature detecting unit 25 is for detecting temperature of the cooling refrigerant at the vicinity of the receiving unit 22 to produce a temperature signal which is representative of the temperature. Responsive to the temperature signal, the automatic expansion valve 19 is automatically driven to adjust the amount of flow of the liquid phase refrigerant component. In this event, the gaseous phase refrigerant component is gradually modified into a modified refrigerant of a liquid phase. Therefore, a combination of the evaporator 18 and the receiving unit 22 may be referred to as a liquefying arrangement. The modified refrigerant is collected at a lower portion of the hollow space of the receiving unit 22. The storage container 26 is placed under the receiving unit 22 and is connected to the hollow space of the receiving unit 22 through a pipe 27. Therefore, the modified refrigerant flows down from the receiving unit 22 towards the storage container 26 through the pipe 27 by gravitational force thereof. As a result, the modified refrigerant is charged into the storage container 26. Apparently, the modified refrigerant has a relatively higher purity in the storage container 26. When the storage container 26 has inner pressure which becomes higher than that of the hollow space of the receiving unit 22, the modified refrigerant is prevented from charging thereof towards the storage container 26. For controlling inner pressure of the storage container 26, a communication pipe 31 is connected between returning pipe 24 and an upper portion of the storage container 26 to communicate the returning pipe 24 with an inner space of the storage container 26. The communication pipe 31 has, at a part thereof, a regulating element 32 such as a capillary tube which is well known in the art. Therefore, it is possible to cause movement of the modified refrigerant of the gaseous phase from the storage container 26 towards the returning pipe 24 through the communication pipe 31 so as to control the inner pressure of the storage container 26. The refrigerant charging system further comprises a pressure detecting unit 33 and an electromagnetic valve 34 which will be presently described. The pressure detecting unit 33 is coupled to the returning pipe 24 at an inlet side of the compressor 13 and is for detecting pressure of the original refrigerant to produce a condition signal which is representative of the pressure. The condition signal is sent from the pressure detecting unit 33 to electromagnetic valve 34. The electromagnetic valve 34 is coupled to the communication pipe 31. Responsive to the condition signal, the electromagnetic valve 34 is automatically driven to adjust the movement of the modified refrigerant through the communication pipe 31. The combination of the communication pipe 31, the pressure detecting unit 33, and the electromagnetic valve 34 is referred to as a control arrangement. When the modified refrigerant stored in the receiving unit 22 exceeds a predetermined amount, effectiveness of the heat exchange is suddenly decreased in the liquefying arrangement. In this condition, part of the cooling refrigerant flows into the returning pipe 24 without being evaporated in the evaporator 18. As a result, the temperature of the returning pipe 24 is lowered. This is because the part of the cooling refrigerant is evaporated in the returning pipe 24 at the vicinity of the liquefying arrangement. When the temperature is lowered, the automatic expansion valve 19 is driven in response to the temperature signal to decrease flowing of the cooling refrigerant. This results in lowering of suction pressure of the compressor 13. When the suction pressure is lower than a first predetermined level, the electromagnetic valve 34 is driven in response to the condition signal to open the communication pipe 31. As a result, the inner pressure of the storage container 26 is lowered, so that the modified refrigerant smoothly flows from the receiving unit 22 into the storage container 26. Therefore, the amount of the modified refrigerant becomes lower than the predetermined amount in the receiving unit 22. When the amount of modified refrigerant is reduced in the receiving unit 22, the effectiveness of the heat exchange is increased in the liquefying arrangement. In this condition, all of the cooling refrigerant is evaporated in the evaporator 18. As a result, the temperature of the returning pipe 24 is returned to its original temperature. When the temperature of the returning pipe 24 is equal to the original temperature, the automatic expansion valve 19 is driven in response to the temperature signal to increase flowing of the cooling refrigerant. This results in rising of the suction pressure of the compressor 13. When the suction pressure is higher than a second predetermined level which is higher than the first predetermined level, the electromagnetic valve 34 is driven in response to the condition signal to close the communication pipe 31. Therefore, the object refrigerant can be smoothly charged into the storage container 26 by repeating the operation described before. Fig. 2, shows a refrigerant charging apparatus according to a second embodiment of this invention. The refrigerant charging system comprises similar parts designated by the same reference numerals used in Fig. 1. The refrigerant charging system comprises a communication pipe 41 for communicating the inner space of the storage container 26 with the hollow space of the receiving unit 22. The communication pipe 41 has first and second ends which are connected between an upper portion of the receiving unit 22 and an upper portion of the storage container 26, respectively. When the modified refrigerant is supplied to the storage container 26, it will be assumed that the inner pressure of the storage container 26 becomes higher dependent on increase of volume of the modified refrigerant in the storage container 26. However, the inner pressure of the storage container 26 is usually held to be substantially constant. This is because the inner pressure is leaked from the storage container 26 to the receiving unit 22 through the communication pipe 41. Therefore, the modified refrigerant can be smoothly charged into the storage container 26. With this refrigerant charging system, it is unnecessary to provide the condition detecting unit and the electromagnetic valve which are depicted at numerals 33 and 34 in Fig. 1. While the present invention has thus far been described in connection with two embodiments thereof, it will readily be possible for those skilled in the art to put this invention into practice in various other manners. For example, the regulating element 32 may be a conventional expansion valve.

Claims: A refrigerant charging apparatus for use in charging into a storage container (26) an object refrigerant which is produced from an original refrigerant, said refrigerant charging apparatus including processing means (13, 14, 15, 16) for processing said original refrigerant to produce a gaseous phase and a liquid phase refrigerant, receiving means (22) for receiving said object refrigerant, cooling means (18) coupled to said receiving means for cooling said object refrigerant to produce a modified refrigerant by use of a cooling refrigerant, and sending means (27) for sending said modified refrigerant to said storage container (26) as said object refrigerant, characterized by: first supplying means (23) coupled to said processing and said receiving means for supplying said gaseous phase refrigerant to said receiving means as said object refrigerant; second supplying means (21) coupled to said processing and said cooling means for supplying said liquid phase refrigerant through a pressure reduction valve (19) to said cooling means as said cooling refrigerant; and controlling means (31, 33, 34) coupled to said storage container for controlling the inner pressure of said storage container to keep this pressure at or below the pressure in said receiving means (22) to facilitate charging of said modified refrigerant to said storage container. A refrigerant charging apparatus as claimed in claim 1, further comprising original supplying means (11) coupled to said processing means for supplying said original refrigerant to said processing means. A refrigerant charging apparatus as claimed in claim 2, wherein said controlling means comprises communication means (31, 32) coupled to said storage container (26) and said original supplying means (11) for communicating the inner space of said storage container (26) with said original supplying means (11). The refrigerant charging apparatus as claimed in claim 3, wherein said controlling means further comprises: detecting means (33) coupled to said original supplying means (11) for detecting the pressure of said original refrigerant to produce a condition signal; and valve means (34) coupled to said detecting and said communicating means and responsive to said condition signal for adjusting movement of said modified refrigerant through said communication means. A refrigerant charging apparatus as claimed in claim 3, said original supplying means (11) comprising returning means (24) coupled to said cooling and said processing means for returning said cooling refrigerant from said cooling means (18) to said processing means, wherein said communication means (31, 32) is coupled to said returning means (24) for communicating said inner space of the storage container (26) with said returning means (24). The refrigerant charging apparatus as claimed in claim 3, wherein said communication means (31) comprises a capillary tube (32). The refrigerant charging apparatus as claimed in claim 5, said receiving means (22) defining a hollow space, said cooling means (18) comprising an evaporator thermally coupled to said hollow space for causing evaporation of said cooling refrigerant therein, wherein said refrigerant charging apparatus further comprises: temperature detecting means (25) thermally coupled to said returning means (24) for detecting the temperature of said cooling refrigerant to produce a temperature signal, said pressure reduction valve (19) being responsive to said temperature signal for adjusting the flow of said liquid phase refrigerant component. The refrigerant charging apparatus as claimed in claim 1, said receiving means (22) defining a hollow space which is thermally coupled to said cooling means (18), wherein said controlling means comprises communication means (41) coupled to said storage container (26) and said receiving means (22) for communicating the inner space of said storage container (26) with said hollow space. The refrigerant charging apparatus as claimed in claim 8, further comprising returning means (24) coupled to said cooling and said processing means for returning said cooling refrigerant from said cooling means (18) to said processing means, wherein said refrigerant charging apparatus further comprises: temperature detecting means (25) thermally coupled to said returning means (24) for detecting the temperature of said cooling refrigerant to produce a temperature signal, said pressure reduction valve (19) being responsive to said temperature signal for adjusting the flow of said liquid refrigerant.

Inventors: TOMARU, KEIICHI
Applicants: SANDEN CORPORATION
Application year: 1989
Main classification: F25B45
IPC codes: F25B45