JP2001174108A - Method for preventing backflow in refrigerant recovery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the time and quantity of leakage by preventing backflow of refrigerant, recovered using an absorbent during leakage of combustible refrigerant, to the refrigeration cycle. SOLUTION: A refrigeration cycle comprises a compressor 1, a condenser 2, an evaporator 3, a pressure reducing unit 4, and a refrigerant recovering unit 5 wherein backflow of refrigerant absorbed to an adsorbent 8 is prevented by closing an on/off valve 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant recovery apparatus for recovering refrigerant when a refrigerant leaks in a refrigeration cycle, and prevents the refrigerant once recovered from flowing back into the refrigeration cycle.

[0002]

2. Description of the Related Art At present, a refrigerant of a heat pump type refrigerator uses a CFC-based refrigerant from the viewpoint of stable physical properties and easy handling.

[0003] CFC-based refrigerants are said to have stable physical properties and are easy to handle, but they also destroy the ozone layer. From the viewpoint of adversely affecting the global environment, a preparation period is set and their use is banned in the future.

[0004] Among HFC-based refrigerants, HFC-based refrigerants have no destruction of the ozone layer, but have the property of promoting global warming.
Its use is not environmentally favorable. Therefore, natural refrigerants such as hydrocarbons are being studied.

[0005] When natural refrigerants such as hydrocarbons and ammonia leak from the refrigeration cycle, there is a method of recovering the refrigerant from the leaking refrigeration cycle using an adsorbent or an absorbent.

Further, as a method for preventing the backflow of the refrigerant once recovered, there is a method for efficiently recovering Freon as disclosed in Japanese Patent Application Laid-Open No. HEI 6-117733.

[0007]

When a flammable refrigerant leaks, it is necessary to suppress the amount of the leak and minimize the generation of the lower limit of flammability in consideration of safety and health.

In the method of recovering the first refrigerant with an adsorbent or the like described in the prior art, the refrigerant once recovered is caused by a decrease in pressure during the refrigeration cycle and an increase in temperature due to heat generated by the adsorbent in the adsorbent filling section. Leaks persist slowly but slowly due to desorption.

The second method of recovering CFCs has no problem when the refrigerant is intentionally recovered, but has no effect when the refrigerant accidentally leaks.

The present invention has been made in view of the above-mentioned problems of the prior art, and by applying a refrigerant backflow prevention method to a refrigerant recovery device using an adsorbent for adsorbing a refrigerant, a refrigeration cycle can be quickly performed when refrigerant leakage occurs. The purpose is to collect the refrigerant in the refrigerant recovery device and seal it.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a refrigerant recovery device filled with an adsorbent or an absorbent having a characteristic of adsorbing or absorbing a natural refrigerant after a certain period of time. A timer device for closing the valve is provided. At the time of refrigerant leakage, the on-off valve between the refrigeration cycle and the adsorbent filling section in the refrigerant recovery device is closed after a certain period of time after the refrigerant is adsorbed on the adsorbent, thereby preventing backflow of the recovered refrigerant and preventing leakage. And the concentration can be reduced, and the possibility of ignition can be reduced and safety can be improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve the above-mentioned problems, the present invention is directed to a refrigeration cycle system in which a combustible refrigerant is circulated by connecting a compressor, a condenser, an evaporator, and a pressure reducing device by a refrigerant pipe. After the start of refrigerant leakage in a refrigeration cycle provided with a refrigerant recovery device that recovers the flammable refrigerant with an adsorbent or an absorbent at the time of refrigerant leakage, after a certain period of time, an on-off valve in the refrigerant recovery device is set at a preset time. It is provided with a timer device for issuing an on-off valve closing signal and on-off valve closing means. This makes it possible to prevent the once recovered refrigerant from flowing back into the refrigeration cycle.

According to a second aspect of the present invention, a compressor, a condenser, an evaporator, and a decompression device are connected to each other by a refrigerant pipe to circulate a flammable refrigerant. In the refrigerant recovery apparatus to be recovered, the first control means for issuing a signal for closing the on-off valve of the refrigerant recovery apparatus when the pressure detection means and the pressure signal obtained from the pressure detection means are in an equilibrium state in the refrigeration cycle. A valve closing means is provided. Thus, the saturated state of the adsorbent can be detected more accurately, and the backflow of the refrigerant once recovered to the refrigeration cycle can be more effectively prevented.

According to a third aspect of the present invention, there is provided a refrigeration cycle system for circulating a combustible refrigerant by connecting a compressor, a condenser, an evaporator, and a pressure reducing device by a refrigerant pipe, and the refrigerant is leaked when the refrigerant is leaked. In the refrigerant recovery device that recovers
A second signal for closing the on-off valve of the refrigerant recovery device when the pressure signal obtained from the pressure detection device and the pressure detection device once rises in the absorbent filling section inside the refrigerant recovery device and then becomes equilibrated. And control means and on-off valve closing means. As a result, the saturated state of the adsorbent can be detected more accurately, and the backflow of the once recovered refrigerant to the refrigeration cycle can be prevented more effectively.

According to a fourth aspect of the present invention, there is provided a refrigeration cycle system in which a compressor, a condenser, an evaporator, and a pressure reducing device are connected by a refrigerant pipe to circulate a flammable refrigerant. In the refrigerant recovery device that recovers
A third control unit and an on-off valve closing unit for issuing an on-off valve closing signal of the refrigerant recovery device when a temperature signal obtained from the temperature detecting unit and the temperature signal obtained from the temperature detecting unit are in an equilibrium state after the temperature drops in the refrigeration cycle. It is provided. As a result, the saturated state of the adsorbent can be detected at lower cost, and the once collected refrigerant can be prevented from flowing back to the refrigeration cycle.

According to a fifth aspect of the present invention, there is provided a refrigeration cycle system in which a compressor, a condenser, an evaporator, and a decompression device are connected by a refrigerant pipe to circulate a combustible refrigerant. In the refrigerant recovery device that recovers
A fourth signal generating an on-off valve closing signal of the refrigerant recovery device when the temperature detection means and a temperature signal obtained from the temperature detection device are heated to an equilibrium state in the adsorbent filling section provided in the refrigerant recovery device. And control means and on-off valve closing means. This makes it possible to detect the saturated state of the adsorbent inexpensively and accurately.

According to a sixth aspect of the present invention, there is provided a refrigeration cycle system in which a compressor, a condenser, an evaporator, and a decompression device are connected by a refrigerant pipe to circulate a flammable refrigerant. In the refrigerant recovery device to be recovered, a temperature detecting means is provided at the most downstream portion of the refrigerant recovery device, and a fifth signal for opening and closing the on-off valve of the refrigerant recovery device when a temperature signal obtained from the temperature detecting means increases in temperature. And control means and on-off valve closing means. This makes it possible to easily detect the saturated state of the adsorbent and prevent the refrigerant from flowing back into the refrigeration cycle when the adsorbent is in the adsorbent-filled state in which the adsorbent sequentially adsorbs.

The invention according to claim 7 is provided in a refrigeration cycle system in which a compressor, a condenser, an evaporator, and a decompression device are connected by a refrigerant pipe to circulate a flammable refrigerant, and the flammable refrigerant is leaked when a refrigerant leaks. In the refrigerant recovery apparatus for recovering the refrigeration cycle, a check valve is provided at a connection portion with the refrigeration cycle.
This makes it possible to more easily prevent the once collected refrigerant from flowing back into the refrigeration cycle.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a configuration diagram of a refrigeration cycle according to the present invention, wherein 1 is a compressor, 2 is a condenser, 3 is an evaporator, and 4 is a decompression device, which includes a capillary tube and an expansion valve. 5 is a refrigerant recovery device, 6 is a refrigerant pipe connecting each part, 7 is an on-off valve, 8 is an adsorbent filling section, 9 is an adsorbent, and propane, isobutane, ammonia, methane, A combustible refrigerant such as ethane is used, 10 is a timer device, 11 is an on-off valve closing means, and various motors and electromagnetic coils are used. In this refrigeration cycle, the functions of the condenser 2 and the evaporator 3 may be switched using a four-way valve. FIG. 2 is a diagram showing the relationship between the refrigerant leakage amount and the indoor concentration of the leakage refrigerant. The refrigerant is discharged from the compressor as high-pressure vapor, cooled and liquefied by the condenser 2, then decompressed by the decompression device 4 to become a low-temperature refrigerant, absorbed by the evaporator 3 and converted into low-pressure vapor to be sucked into the compressor 1.

The adsorbent filling section 8 inside the refrigerant recovery device 5 connected to the refrigeration cycle is filled with an adsorbent 9, such as zeolite or activated carbon, having at least the ability to adsorb the refrigerant. The refrigerant recovery device 5 and the refrigerant pipe 6 are connected between the adsorbent filling section 8 and the refrigerant pipe 6 via an on-off valve 7, and the position of the on-off valve 7 may be inside the refrigerant recovery device 5.

When the refrigerant leaks, the on-off valve 7 is opened and the adsorption of the refrigerant to the adsorbent 9 filled in the adsorbent filling section 8 starts. When the adsorption of the refrigerant is completed, the desorption of the refrigerant from the adsorbent 9 starts. At this time, when a preset time comes from the amount of the refrigerant sealed in the refrigeration cycle and the adsorption capacity of the adsorbent 9, etc., the timer device 10 sends an on / off valve closing signal 10A to the on / off valve closing means 11 to close the on / off valve 7. This can prevent the refrigerant adsorbed by the adsorbent 9 from flowing back to the refrigeration cycle.

(Embodiment 2) FIG. 3 is a configuration diagram of a refrigeration cycle according to the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description is omitted. 12 is a pressure detecting means, 13 is a first control means, and 14 is a second control means. FIG. 4 shows a pressure change in the refrigeration cycle when a leak occurs. FIG. 5 shows a pressure change of the adsorbent filling section when a leak occurs.

The pressure detecting means 12 is mounted at an arbitrary position in the refrigeration cycle. When the leakage starts, the pressure starts to decrease in the refrigeration cycle due to the temperature decrease due to the latent heat of evaporation of the refrigerant. However, when the temperature change disappears after the liquid refrigerant has run out and the recovery of the refrigerant to the refrigerant recovery device 5 is saturated, the temperature in the refrigeration cycle reaches an equilibrium state as shown in FIG. At this time, the pressure of the refrigeration cycle is detected by the pressure detecting means 12, the first control means 13 determines that the pressure has reached an equilibrium state, and sends an on / off valve closing signal 13 A to the on / off valve closing means 11 to cause the on / off valve 7 to operate. By closing, it is possible to prevent the refrigerant adsorbed by the adsorbent 9 from flowing back to the refrigeration cycle.

When the pressure detecting means 11 is attached to an arbitrary place of the adsorbent filling section 8, the adsorbent filling section 8 is at a vacuum or a low pressure of about 1 atm before the refrigerant recovery starts, but the refrigerant leaks. As shown in FIG. 5, during the recovery of the refrigerant due to the adsorption, the pressure of the adsorbent filling portion once rises, and thereafter, when the adsorbent 9 reaches saturation, the pressure starts to decrease, and the equilibrium state is established soon. Finally, desorption of the refrigerant adsorbed by the adsorbent 9 starts. At this time, the pressure detecting means 12
, The pressure of the adsorbent filling section is detected, and the second control means 14 judges that the pressure once increased and then reached an equilibrium, and sends an on-off valve closing signal 14A to the on-off valve closing means 11 to close the on-off valve 7. By doing so, it is possible to prevent the refrigerant adsorbed by the adsorbent 9 from flowing back to the refrigeration cycle.

(Embodiment 3) FIG. 6 is a configuration diagram of a refrigeration cycle according to the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description is omitted. Reference numeral 15 denotes a temperature detecting means, 16 denotes a third control means, 17 denotes a fourth control means, and 18 denotes a fifth control means. FIG. 7 shows a temperature change in the refrigeration cycle when a leak occurs. FIG. 8 shows a change in temperature of the adsorbent-filled portion when a leak occurs.

[0027] The temperature detecting means 15 is attached to an arbitrary place of the refrigeration cycle. When the leakage starts, the temperature starts to decrease due to the latent heat of evaporation of the refrigerant in the refrigeration cycle. However, when the temperature change disappears after the liquid refrigerant disappears and the refrigerant recovery to the refrigerant recovery device 5 is saturated, the temperature in the refrigeration cycle reaches an equilibrium state as shown in FIG. At this time, the temperature of the refrigeration cycle is detected by the temperature detecting means 15, the third control means 16 determines that the temperature has reached an equilibrium state, and sends an on / off valve closing signal 16 A to the on / off valve closing means 11 to cause the on / off valve 7 to operate. Adsorbent 9 by closing
The backflow of the refrigerant adsorbed to the refrigeration cycle can be prevented.

The temperature detecting means 14 is connected to the adsorbent filling section 8.
As shown in FIG. 8, when the refrigerant is leaked and the refrigerant is collected by adsorption,
The temperature of the adsorbent-filled portion once rises, and then reaches an equilibrium state when the adsorbent 9 reaches saturation. Finally, the desorption of the refrigerant adsorbed by the adsorbent 9 starts or the temperature decreases. At this time, the temperature of the adsorbent filling section is detected by the temperature detecting means 15 and the fourth
The control means 17 determines that the temperature once rises and then reaches an equilibrium state, and sends an on / off valve closing signal 17A to the on / off valve closing means 11 to close the on / off valve 7 so that the adsorbent 9
The backflow of the refrigerant adsorbed to the refrigeration cycle can be prevented.

Further, the temperature detecting means 15 is particularly connected to the adsorbent filling section 9.
Since the temperature of the most downstream part starts to rise when the adsorption capacity of the adsorbent 9 is used up, particularly in the adsorbent filling section having a structure in which the adsorbent sequentially adsorbs the refrigerant, The temperature is detected by the temperature detecting means 15, the fifth control means 18 determines that the temperature has risen, sends an on / off valve closing signal 18 A to the on / off valve closing means 11, and closes the on / off valve 7, so that the adsorbent 9 is discharged. Backflow of the adsorbed refrigerant to the refrigeration cycle can be prevented.

(Embodiment 4) FIG. 9 is a configuration diagram of a refrigeration cycle according to the present invention. The same components as those in FIG. 19 is a check valve.

The check valve 19 has a characteristic that the fluid flows from the higher pressure to the lower pressure, but does not flow in reverse, so that the refrigerant once collected in the adsorbent filling portion 8 starts to be desorbed. As a result, the refrigeration cycle becomes higher in pressure, so that the backflow of the refrigerant can be prevented.

[0032]

As apparent from the above embodiment, claim 1
According to the invention described above, by providing the timer means and the on-off valve closing means in the refrigerant recovery device and closing the on-off valve a predetermined time after the refrigerant leaks, it is possible to prevent the recovered refrigerant from flowing back to the refrigeration cycle, The amount of leakage is reduced, and as a result, the leakage time is kept short, and the risk of combustion can be reduced.

According to the second aspect of the present invention, by detecting the pressure of the refrigeration cycle and closing the on-off valve, it is possible to detect the limit of the adsorption capacity of the adsorbent, and as a result, the leakage time of the refrigerant due to the refrigerant leakage And the danger can be lower.

According to the third aspect of the present invention, the second aspect is provided.
Compared to the method for detecting a pressure change of a refrigeration cycle according to the described invention, the pressure is relatively stable at the adsorbent-filled part because the leakage point and the surrounding temperature are less affected. Can be detected. By detecting the pressure of the refrigeration cycle and closing the on-off valve, the limit of the adsorption capacity of the adsorbent can be detected more reliably, and as a result, the leakage time and danger of refrigerant due to refrigerant leakage can be further reduced. it can.

According to the fourth aspect of the present invention, by detecting the temperature of the refrigeration cycle and closing the on-off valve, the limit of the adsorbing capacity of the adsorbent can be detected more inexpensively, and the refrigerant leakage due to refrigerant leakage can be detected. Leak time and danger can be reduced. It should be noted that this temperature detecting means can generally be used even if it is already provided in the air conditioner, so that it can be made more inexpensive.

According to the fifth aspect of the present invention, compared to the method of detecting the temperature of the refrigeration cycle according to the fourth aspect of the present invention, the adsorbent filling portion and the adsorbent itself have heat capacities because of their heat capacities. In this case, the temperature is easily stabilized, so that the temperature equilibrium state is more easily detected in the adsorbent filling section than in the refrigeration cycle. For this reason, by detecting the temperature of the adsorbent filling section and closing the on-off valve, the limit of the adsorbent adsorption capacity can be detected more reliably and inexpensively, and the leakage time and danger of refrigerant due to refrigerant leakage are further reduced. Can be lower.

According to the sixth aspect of the present invention, by detecting the temperature of the most downstream portion of the adsorbent filling section of the refrigerant recovery device and closing the on-off valve, the limit of the adsorbent adsorption capacity can be reduced more inexpensively. The leakage time and danger of refrigerant due to refrigerant leakage can be easily reduced.

According to the seventh aspect of the present invention, by providing the check valve, it is possible to prevent the refrigerant automatically collected by the pressure change from flowing back to the refrigeration cycle, and as a result, it is simple and reliable. In addition, the leakage time and danger of the refrigerant can be reduced. By combining this check valve with the invention of claims 1 to 4, for example, the check valve cannot sufficiently prevent backflow if the pressure difference is small,
With the inventions according to the first to sixth aspects, backflow can be prevented even when the pressure difference is small. On the contrary, the inventions according to the first to sixth aspects each have some control means, but these are relatively abnormal. Although it is easy, the backflow of the refrigerant can be reliably prevented even when an abnormality occurs.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a refrigeration system showing a first embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a refrigerant leakage amount and a refrigerant concentration in a leakage space.

FIG. 3 is a schematic diagram of a refrigeration system showing a second embodiment of the present invention.

FIG. 4 is a graph showing a change over time in a refrigeration cycle pressure during refrigerant recovery.

FIG. 5 is a graph of a change with time of the pressure in the adsorbent filling section at the time of refrigerant recovery.

FIG. 6 is a schematic diagram of a refrigeration system showing a third embodiment of the present invention.

FIG. 7 is a graph showing a change over time in a refrigeration cycle temperature during refrigerant recovery.

FIG. 8 is a graph showing the change over time in the temperature inside the adsorbent filling section during refrigerant recovery.

FIG. 9 is a schematic diagram of a refrigeration system showing a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Evaporator 4 Decompression device 5 Refrigerant recovery device 6 Refrigerant piping 7 On-off valve 8 Adsorbent filling part 9 Adsorbent 10 Timer device 11 On-off valve closing means 12 Pressure detection means 13 First control means 14 First 2 control means 15 temperature detection means 16 third control means 17 fourth control means 18 fifth control means 19 check valve

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshikazu Kawabe 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Yukio Watanabe 1006 Kadoma Kadoma, Kadoma City, Osaka Pref. 72) Inventor Yuichi Yakumaru 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] When a refrigerant leaks to a refrigeration cycle system in which a compressor, a condenser, an evaporator, and a pressure reducing device are connected by a refrigerant pipe to circulate the combustible refrigerant, the combustible refrigerant is recovered with an adsorbent or an absorbent. In a refrigeration cycle provided with a refrigerant recovery device, a timer device and an opening / closing valve closing means for issuing an opening / closing valve closing signal at a preset time after a predetermined time has elapsed after the start of the leakage of the refrigerant, and provided in the refrigerant collecting device. Refrigerant backflow prevention method. 2. A refrigerant recovery device which is connected to a compressor, a condenser, an evaporator, and a pressure reducing device by a refrigerant pipe and circulates a flammable refrigerant and circulates the flammable refrigerant. The refrigeration cycle is provided with pressure control means and first control means for issuing an on / off valve closing signal of the refrigerant recovery device when a pressure signal obtained from the pressure detecting means is in an equilibrium state, and on / off valve closing means. Refrigerant backflow prevention method. 3. A refrigerant recovery device which is connected to a compressor, a condenser, an evaporator, and a pressure reducing device by a refrigerant pipe to circulate a combustible refrigerant and which collects the combustible refrigerant when a refrigerant leaks. A second signal generation unit that issues an on-off valve closing signal of the refrigerant recovery device when the pressure signal obtained by the pressure detection unit and the pressure detection unit once rises and reaches an equilibrium state in the absorbent filling section inside the refrigerant recovery device. 2
A method for preventing a backflow of refrigerant, comprising: a control unit of (1) and an on-off valve closing unit. 4. A refrigerant recovery device which is connected to a compressor, a condenser, an evaporator, and a pressure reducing device by a refrigerant pipe and circulates a flammable refrigerant and circulates a flammable refrigerant. A third control means for issuing a signal for closing the on-off valve of the refrigerant recovery device when the temperature signal obtained from the temperature detecting means and the temperature signal obtained from the temperature detecting means are in an equilibrium state after the temperature has dropped, and an on-off valve closing means A method for preventing a backflow of refrigerant. 5. A refrigerant recovery device which is connected to a compressor, a condenser, an evaporator, and a pressure reducing device by a refrigerant pipe and circulates a flammable refrigerant and circulates the flammable refrigerant, and recovers the flammable refrigerant when the refrigerant leaks. A temperature detection unit and a temperature signal obtained from the temperature detection unit in the adsorbent filling unit provided in the refrigerant recovery device, when a temperature rises and an equilibrium state is generated, a signal for closing the on-off valve of the refrigerant recovery device is issued. 4. A refrigerant backflow prevention method comprising the control means and the on-off valve closing means of 4. 6. A refrigerant recovery device which is connected to a compressor, a condenser, an evaporator, and a pressure reducing device by a refrigerant pipe and circulates a flammable refrigerant and circulates a flammable refrigerant, and collects the flammable refrigerant when a refrigerant leaks. And a fifth control means for providing a temperature detection means at the most downstream portion of the refrigerant recovery device and for issuing a signal for closing the on-off valve of the refrigerant recovery device when a temperature signal obtained from the temperature detection means rises in temperature. A refrigerant backflow prevention method provided with valve closing means. 7. A refrigerant recovery apparatus for connecting a compressor, a condenser, an evaporator, and a decompression device by a refrigerant pipe and circulating a flammable refrigerant and circulating the flammable refrigerant and recovering the flammable refrigerant when the refrigerant leaks. A method for preventing a refrigerant from flowing backward, wherein a check valve is provided at a connection portion with a refrigeration cycle.