JP6914210B2 - Refrigerant leak detection device, refrigerant leak detection method, and refrigerant leak detection system - Google Patents

Description

The present invention relates to a refrigerant leak detection device that detects a refrigerant leak from a refrigerant pipe, a refrigerant leak detection method, and a refrigerant leak detection system.

In recent years, it has been required to suppress leakage of refrigerants such as chlorofluorocarbons, which promote global warming, to the atmosphere. Leakage of the refrigerant into the atmosphere occurs when the refrigerant that was not recovered when disposing of equipment containing the refrigerant such as a refrigerator or air conditioner leaks into the atmosphere, or when the refrigerator or air conditioner is in use. Refrigerant may leak to the atmosphere from equipment or piping.

Recent studies have shown that the amount of refrigerant that leaks into the atmosphere during equipment use is as much as the amount of refrigerant that leaks into the atmosphere when the equipment is disposed of. Therefore, it is required to detect the leakage of the refrigerant during the use of the device. It is also required to identify the location of the leak in order to carry out repairs to stop the refrigerant leak.

For this reason, sensors with electrodes sandwiching a special substance whose capacitance changes due to the adsorption of refrigerating machine oil leaking from the refrigerant pipe together with the refrigerant are attached to various parts of the refrigerant pipe to detect and generate leakage. A refrigerant leakage detection device that identifies a location has been proposed (see, for example, Patent Document 1).

JP-A-2010-101515

By the way, in order to identify the location where the refrigerant leaks to the extent that repairs can be performed to stop the refrigerant leak, it is necessary to attach sensors to many places in the refrigerant pipe. However, the conventional sensor described in Patent Document 1 has a complicated structure, and there is a problem that the leakage detection system becomes complicated when many sensors are attached to the refrigerant pipe.

Therefore, an object of the present invention is to detect a refrigerant leak and identify a location where a refrigerant leak occurs with a simple configuration.

The refrigerant leakage detection device of the present invention has a capacitance between an electrode band which is a substantially annular metal thin film wound around the outer periphery of a heat insulating material covering the outer surface of a metal refrigerant pipe through which a refrigerant flows and the refrigerant pipe. Based on this, it is a refrigerant leakage detection device that detects the leakage of refrigerant from the refrigerant pipe, and the metal thin film of the electrode band is wound in the winding direction on a flexible insulating sheet that is wound around the outer periphery of the heat insulating material. It is characterized in that it is formed so as to extend.

The refrigerant leakage detection device of the present invention includes an electrode band set in which a plurality of the electrode bands are arranged with a gap along the longitudinal direction of the refrigerant pipe, and each capacitance between each of the electrode bands and the refrigerant pipe is provided. The region where the electrode band is arranged may be the location where the refrigerant leaks, when the capacitance is measured and the capacitance larger than a predetermined threshold is detected.

In the refrigerant leakage detection device of the present invention, the insulating sheet includes a wiring that connects an end portion in a direction perpendicular to the winding direction and the electrode band, and the wiring is a linear metal formed on the insulating sheet. It may be a thin film.

The refrigerant leakage detection method of the present invention is a refrigerant leakage detection method for detecting a refrigerant leakage from a metal refrigerant pipe through which a refrigerant flows, and is a substantially annular shape wound around the outer periphery of a heat insulating material covering the outer surface of the refrigerant pipe. An electrode band which is a metal thin film of the above, wherein the metal thin film is formed so as to extend in the winding direction on a flexible insulating sheet wound around the outer periphery of the heat insulating material in the longitudinal direction of the refrigerant pipe. A plurality of electrode band sets arranged with a gap along the above are prepared, each electrostatic capacity between each of the electrode bands and the refrigerant pipe is measured, and an electrostatic capacity larger than a predetermined threshold value is detected. It is characterized in that the region where the electrode band is arranged is the location where the refrigerant leaks.

The refrigerant leakage detection device of the present invention is a refrigerant leakage detection device that detects leakage of refrigerant from a metal refrigerant pipe through which the refrigerant flows, and includes a substantially annular inner electrode band wound around the outer periphery of the refrigerant pipe. A substantially annular outer electrode band, which is wound around the outer periphery of the heat insulating material covering the outer surface of the inner electrode band so as to face the inner electrode band and forms a capacitor with each of the inner electrode bands, is described. A plurality of electrode bands are arranged with a gap along the longitudinal direction of the refrigerant pipe to form a plurality of capacitor sets arranged along the longitudinal direction of the refrigerant pipe, and each of the electrodes formed by the electrode band sets is provided. Leakage of the refrigerant is detected based on the change in capacitance between the two, and the inner electrode band is formed so as to extend in the winding direction on a flexible inner insulating sheet wound around the outer periphery of the refrigerant pipe. It is a metal thin film, and the outer electrode band is a metal thin film formed so as to extend in the winding direction on a flexible outer insulating sheet wound around the outer periphery of the heat insulating material covering the outer surface of the inner electrode band. It is characterized by being.

In the refrigerant leakage detection device of the present invention, among the plurality of capacitors formed by the electrode band assembly, the four inner electrodes are such that four capacitors adjacent to each other in the longitudinal direction of the refrigerant pipe form one bridge circuit. A current is supplied to the connection circuit connecting the band and the four outer electrode bands facing the inner electrode band and the bridge circuit configured by the connection circuit, and the current value flowing through the measurement electric circuit of the bridge circuit. A current detector may be provided to detect the leakage of the refrigerant based on the magnitude of the current value detected by the current detector.

In the refrigerant leakage detection device of the present invention, among the plurality of capacitors formed by the electrode band assembly, the four insides are formed so as to form one bridge circuit for each of the four capacitors adjacent in the longitudinal direction of the refrigerant pipe. By connecting a plurality of sets of the electrode band and the four outer electrode bands facing the inner electrode band to form a plurality of the bridge circuits arranged in the longitudinal direction of the refrigerant pipe, and the connection circuit. A current that supplies a current to each of the configured bridge circuits and detects each current value flowing in each measurement electric path of each of the bridge circuits, and a current that detects a current larger than a predetermined threshold value. The region where the inner electrode band and the outer electrode band constituting the bridge circuit to which the detector is connected may be arranged may be a location where the leakage of the current occurs.

In the refrigerant leakage detection device of the present invention, the connection circuit is connected to the connection circuit so as to sequentially shift a set of four capacitors constituting one bridge circuit in the longitudinal direction of the refrigerant pipe. The set of the inner electrode band and the four outer electrode bands facing the inner electrode band may be sequentially shifted in the longitudinal direction of the refrigerant pipe.

In the refrigerant leakage detection device of the present invention, the inner insulating sheet and the outer insulating sheet each include a wiring connecting an end portion in a direction perpendicular to the winding direction and the inner electrode band or the outer electrode band, and the wiring. May be a linear metal thin film formed on the inner insulating sheet or on the outer insulating sheet.

Refrigerant leakage detection method of the present invention, from the refrigerant tube made of metal through which the refrigerant flows a refrigerant leakage detection method for detecting a leak of the refrigerant, the inner insulating sheet of flexible that wound on the outer periphery of said coolant tube the inner side electrode strips substantially annular composed of a metal thin film formed so as to extend in the winding direction on a flexible outer insulating sheet that is wound around the outer circumference of the heat insulating material covering the outer surface of the inner electrode strip formed of a metal thin film formed so as to extend in the winding direction over, an outer side electrode strips substantially annular forming a capacitor between each said inner electrode strip to face the inner electrode strip, respectively A plurality of electrode band sets are arranged with a gap along the longitudinal direction of the refrigerant pipe, and an electrode band set forming a plurality of capacitor sets arranged along the longitudinal direction of the refrigerant pipe is prepared, and the electrode band set is formed by the electrode band set. performing the leak detection of refrigerant based on the change in capacitance between the capacitors, characterized by.

In the refrigerant leakage detection method of the present invention, among the plurality of capacitors formed by the electrode band assembly, the four inner electrodes are formed so that four capacitors adjacent to each other in the longitudinal direction of the refrigerant pipe form one bridge circuit. The band and the four outer electrode bands facing the inner electrode band are connected to supply a current to the bridge circuit, and the current value flowing in the measurement electric circuit of the bridge circuit is detected, and the magnitude of the detected current value is detected. The leakage of the refrigerant may be detected based on the above.

In the refrigerant leakage detection device of the present invention, the predetermined threshold value may be set to a different numerical value depending on the mode of the refrigerant.

The refrigerant leakage detection system of the present invention is a refrigerant leakage detection system that identifies a location where a refrigerant leaks from a metal refrigerant pipe through which the refrigerant flows, and is wound around the outer periphery of a heat insulating material that covers the outer surface of the refrigerant pipe. A plurality of electrode bands, which are substantially annular metal thin films, are arranged with a gap along the longitudinal direction of the refrigerant pipe, and the metal thin film of the electrode bands is flexible and is wound around the outer periphery of the heat insulating material. It is formed so as to extend in the winding direction on the property insulating sheet, and each capacitance between each of the electrode bands and the refrigerant pipe is sequentially measured, and a capacitance larger than a predetermined threshold is detected. the arrangement area of the electrode strip which is to be a leakage occurrence point of the refrigerant, characterized by.

In the refrigerant leakage detection system of the present invention, the predetermined threshold value may be set to a different numerical value depending on the mode of the refrigerant.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to detect refrigerant leakage and identify the location where refrigerant leakage occurs with a simple configuration.

It is a perspective view which shows the state which attached the refrigerant leakage detection apparatus in embodiment of this invention to a refrigerant pipe. FIG. 1A is a plan view showing a state in which the electrode sheet assembly shown in FIG. 1 is unfolded in the circumferential direction, and FIG. 3B is a perspective view showing a state in which the electrode sheet assembly is wound around an outer surface of a heat insulating material of a refrigerant pipe. It is a perspective view which shows the state which wound the electrode sheet assembly and the wiring assembly around the outer surface of the heat insulating material of a refrigerant pipe. It is a perspective view which shows the state which attached the refrigerant leakage detection apparatus in embodiment of this invention to a refrigerant pipe. It is a diagram which shows the wiring of the electrode band of the refrigerant leakage detection device shown in FIG. 4, the connection circuit, and the current detector. It is a circuit diagram which shows the bridge circuit which comprises the electrode band of the refrigerant leakage detection apparatus shown in FIG. 4, a connection circuit, and a current detector. It is a wiring diagram which shows the structure of another refrigerant leakage detection device which arranged two refrigerant leakage detection devices of the same structure as the refrigerant leakage detection device shown in FIG. 4 side by side in the longitudinal direction of a refrigerant pipe. It is a circuit diagram of the refrigerant leakage detection device shown in FIG. 7. It is a wiring diagram which shows the structure of another refrigerant leakage detection device which attached the connection switching device to the refrigerant leakage detection device shown in FIG. 7. It is a system diagram which shows the structure of the refrigerant leakage detection system of embodiment. It is sectional drawing which shows the detail of part A shown in FIG. It is sectional drawing which shows the other embodiment of the part A of FIG.

Hereinafter, the refrigerant leakage detection device 100 of the embodiment will be described with reference to the drawings. As shown in FIG. 1, the refrigerant pipe 10 to which the refrigerant leakage detection device 100 of the present embodiment is attached is made of a metal such as copper, and the refrigerant 11 flows inside. Since there is a temperature difference between the temperature of the refrigerant 11 and the temperature of the outside air, a heat insulating material 12 is attached to the outer surface of the refrigerant pipe 10 so that the temperature of the refrigerant 11 does not change due to the outside air. The refrigerant leakage detection device 100 of the present embodiment includes an electrode sheet assembly 20 wound around the outer periphery of a heat insulating material 12 that covers the outer surface of the refrigerant pipe 10, and a capacitance meter 25.

As shown in FIG. 2A, the electrode sheet assembly 20 is formed by forming a plurality of metal thin film electrode bands 22 on a flexible insulating sheet 21 such as a resin sheet, for example. The insulating sheet 21 is a rectangular sheet that is long in the longitudinal direction of the refrigerant pipe 10, and four electrode bands 22 are formed with a gap in the longitudinal direction of the refrigerant pipe 10. The circumferential length of the insulating sheet 21 is substantially the same as the outer peripheral length of the heat insulating material 12 that covers the outer surface of the refrigerant pipe 10, and the electrode band 22 extends in the circumferential direction of the insulating sheet 21. It is formed on 21. Further, each output terminal 23 of each electrode band 22 is formed at an end portion of the insulating sheet 21 in the longitudinal direction, that is, an end portion in a direction perpendicular to the winding direction. Each output terminal 23 and each electrode band 22 are connected by each wiring 24. Like the electrode band 22, each output terminal 23 is a metal thin film formed on the insulating sheet 21, and the wiring 24 is a linear metal thin film formed on the insulating sheet 21. For the electrode band 22, the output terminal 23, and the wiring 24, for example, a conductive layer is formed on the insulating sheet 21 by sputtering, vapor deposition, or the like, and parts other than the electrode band 22, the output terminal 23, and the wiring 24 are removed by etching. The electrode band 22, the output terminal 23, and the wiring 24 may be printed on the insulating sheet 21 using conductive ink.

When the electrode sheet assembly 20 shown in FIG. 2A is wound around the outer surface of the heat insulating material 12 of the refrigerant pipe 10, the flat electrode band 22 shown in FIG. 2A covers the outer surface of the refrigerant pipe 10. The electrode band 22 is a substantially annular electrode band that is wound around the outer periphery of the heat insulating material 12 that covers the material. Further, the plurality of electrode bands 22 are arranged with a gap in the longitudinal direction of the refrigerant pipe 10. Then, at the end of the refrigerant pipe 10 of the electrode sheet assembly 20 in the longitudinal direction, each output terminal 23 connected to each electrode band 22 is arranged.

ここで、
Ｌは、電極帯２２の冷媒管１０の長手方向の長さである。
ε_０は、真空の誘電率である。
ε_Ｓは、断熱材１２の比誘電率である。
Ｒ１は、冷媒管１０の外半径である。
Ｒ２は、断熱材１２の外半径である。 As shown in FIG. 1, when the electrode sheet assembly 20 is wound around the outer surface of the heat insulating material 12 of the refrigerant pipe 10, a predetermined capacitance is provided between each electrode band 22 and the metal refrigerant pipe 10. An annular capacitor is formed. The capacitance C of the annular capacitor is calculated by the following equation (1).

here,
L is the length of the refrigerant pipe 10 of the electrode band 22 in the longitudinal direction.
ε ₀ is the permittivity of the vacuum.
ε _S is the relative permittivity of the heat insulating material 12.
R1 is the outer radius of the refrigerant pipe 10.
R2 is the outer radius of the heat insulating material 12.

As shown in FIG. 1, the refrigerant pipe 10 and the output terminal 23 of the electrode band 22 are connected to a capacitance meter 25, and the capacitance between the electrode band 22 and the refrigerant pipe 10 is provided by the capacitance meter 25. Is detected.

When the refrigerant 11 leaks from the refrigerant pipe 10 in a liquid state, the liquid refrigerant 11 enters the heat insulating material 12. Since the relative permittivity of the liquid refrigerant 11 is larger than the relative permittivity of the heat insulating material 12, when the liquid refrigerant 11 enters the heat insulating material 12, _{the value of ε S} in the equation (1) becomes large. Become. Therefore, when the liquid refrigerant 11 leaks, the capacitance between the electrode band 22 near the leakage occurrence location and the refrigerant pipe 10 is static between the electrode band 22 and the refrigerant pipe 10 where there is no leakage. It becomes larger than the electric capacity.

As an example, the length L of the refrigerant pipe 10 of the electrode band 22 in the longitudinal direction is 100 (mm), the outer radius R1 of the refrigerant pipe 10 is 5 (mm), and the outer radius R2 of the heat insulating material 12 is 25 (mm). When the specific dielectric constant ε _S of the heat insulating material 12 is 2.4 to 3.6 and the specific attraction ratio of the refrigerant 11 in the liquid state is 90, the static between the electrode band 22 and the refrigerant pipe 10 in the non-leakage portion is static. The electric capacity is about 20 pF, and the electrostatic capacity between the electrode band 22 near the leakage occurrence location of the refrigerant 11 in the liquid state and the refrigerant pipe 10 is about 180 pF. As described above, when the refrigerant 11 leaks in the liquid state, the capacitance between the electrode band 22 and the refrigerant pipe 14 in the vicinity thereof changes significantly. Therefore, as shown in FIG. 1, by detecting the capacitance between the electrode band 22 and the refrigerant pipe 10 with the capacitance meter 25, leakage of the refrigerant 11 in the liquid state can be detected. .. Further, when the capacitance detected by the capacitance meter 25 is larger than a predetermined threshold value, it can be specified that the liquid refrigerant 11 leaks in the vicinity of the electrode band 22. ..

Further, the refrigerant 11 may leak in a gaseous state. The relative permittivity of the refrigerant 11 in the gaseous state is smaller than the relative permittivity of the refrigerant 11 in the liquid state. Therefore, when the refrigerant 11 leaks in a gaseous state, the change in capacitance between the electrode band 22 and the refrigerant pipe 10 is smaller than when the liquid refrigerant 11 leaks, but the refrigerant 11 By detecting the electrostatic capacity between the electrode band 22 and the refrigerant pipe 10 with the capacitance meter 25 as in the case of leakage in the liquid state, leakage of the refrigerant 11 in the gaseous state can be detected or electrostatic. When the capacitance detected by the capacitance meter 25 is larger than a predetermined threshold value, it is possible to identify that the refrigerant 11 in the gaseous state is leaking in the vicinity of the electrode band 22. However, the predetermined threshold value may be a threshold value smaller than the threshold value in the case of specifying the leakage position of the liquid refrigerant 11.

Further, when the refrigerant 11 leaks from the refrigerant pipe 10, the refrigerating machine oil flowing in the refrigerant pipe 10 may also leak. For example, the liquid refrigerant 11 may leak from the refrigerant pipe 10 in a gaseous state with refrigerating machine oil. Similar to the example described above, the length L of the refrigerant pipe 10 of the electrode band 22 in the longitudinal direction is 100 (mm), the outer radius R1 of the refrigerant pipe 10 is 5 (mm), and the outer radius R2 of the heat insulating material 12 is 25 ( mm), when the relative dielectric constant ε _S of the heat insulating material 12 is 2.4 to 3.6, the specific attraction of the refrigerant 11 in the gaseous state is about 1, and the relative dielectric constant of the refrigerating machine oil is about 5, leakage occurs. The electrostatic capacity between the electrode band 22 and the refrigerant pipe 10 in the non-existent portion is about 8 pF, and the electrostatic capacity between the electrode band 22 and the refrigerant pipe 10 near the leakage occurrence point between the gaseous refrigerant 11 and the refrigerating machine oil. The capacity is about 20 pF. As a result, as in the example described above, the leakage between the gaseous refrigerant 11 and the refrigerating machine oil is detected by detecting the capacitance between the electrode band 22 and the refrigerant pipe 10 with the capacitance meter 25. Or, when the capacitance detected by the capacitance meter 25 is larger than a predetermined threshold value, it is determined that the refrigerant 11 in the gaseous state and the refrigerating machine oil leak in the vicinity of the electrode band 22. Can be identified. However, the predetermined threshold value may be different from the threshold value when the leakage position of the liquid refrigerant 11 is specified and the threshold value when the leakage occurrence location of the gaseous refrigerant 11 is specified.

As described above, as an example, the case where the refrigerant 11 leaks in the liquid state, the case where the liquid refrigerant 11 leaks in the gaseous state, and the case where the liquid refrigerant 11 leaks in the gaseous state accompanied by the refrigerating machine oil have been described. The same method is used to detect when the gaseous refrigerant 11 is flowing through the refrigerant pipe 10 and the gaseous refrigerant 11 leaks, and when the gaseous refrigerant 11 leaks with the refrigerating machine oil. Is possible. Of course, it is also possible to detect a case where the refrigerant 11 leaks in a liquid state accompanied by refrigerating machine oil. Further, it is also possible to detect impurities that leak out together with the refrigerant 11, such as condensed water, by the same method.

At this time, the predetermined threshold value for identifying the leakage occurrence location may be a different numerical value depending on the mode of the refrigerant 11. For example, in the section of the refrigerant pipe 10 through which the gaseous refrigerant 11 flows, the threshold may be smaller than the threshold in the section in which the liquid refrigerant 11 flows, and in the gas section, the ratio of refrigerating machine oil or the like leaking together with the gaseous refrigerant 11 A threshold calculated based on the permittivity may be used.

Further, as shown in FIG. 1, a plurality of electrode bands 22 are arranged side by side at intervals in the longitudinal direction of the refrigerant pipe 10, and the capacitance between each electrode band 22 and the refrigerant pipe 10 is sequentially measured. Therefore, the location where the leakage occurs in the longitudinal direction of the refrigerant pipe 10 can be specified. In the example shown above, the length L of the electrode band 22 in the longitudinal direction is 100 (mm). Therefore, when a plurality of electrode sheet assemblies 20 shown in FIG. 1 are installed in the refrigerant pipe 10 in the longitudinal direction, the length L is 100 (mm). The location where the leakage of the refrigerant pipe 10 occurs can be specified at intervals. Further, by installing the electrode sheet assembly 20 in the refrigerant pipe 10 near the joint of the refrigerant pipe 10 or the welded portion where leakage is likely to occur, the joint or the welded portion in which the refrigerant 11 leaks is identified. can do. As a result, the location where the refrigerant 11 leaks can be specified to the extent that repair work for stopping the leakage of the refrigerant 11 can be performed. A plurality of capacitance meters 25 may be used to detect the capacitance between the plurality of electrode bands 22 and the refrigerant pipe 10.

As described above, the refrigerant leakage detection device 100 of the present embodiment has a simple configuration in which the electrode sheet assembly 20 having the electrode band 22 formed on the surface of the insulating sheet 21 is wound around the outer surface of the heat insulating material 12 of the refrigerant pipe 10. Therefore, the leakage of the refrigerant 11 can be detected and the leakage position can be specified.

In the refrigerant leakage detection device 100 described above, the electrode sheet assembly 20 has been described as being wound around the outside of the heat insulating material 12, but a cover for preventing rainwater from entering the heat insulating material 12 outside the heat insulating material 12. If is attached, the electrode sheet assembly 20 may be wrapped around the outer periphery of the cover. In this case, the predetermined threshold value for detecting leakage may be a value in consideration of the relative permittivity of the cover in addition to the heat insulating material 12, the refrigerant 11 entering the heat insulating material 12, refrigerating machine oil, and the like.

Further, when the electrode sheet assembly 20 is installed in the refrigerant pipe 10, the detection wiring from the output terminal 23 may be arranged along the refrigerant pipe 10 by using the wiring sheet 30 as shown in FIG. .. In the wiring sheet 30, terminals 33 and 34 are formed at both ends of the insulating sheet 31 in the longitudinal direction, and the terminals 33 and 34 are connected by wiring 32 composed of a linear metal thin film. The end of the wiring sheet 30 and the electrode sheet assembly 20 are connected so that the output terminal 23 arranged at the longitudinal end of the electrode sheet assembly 20 and the terminal 33 arranged at one end of the wiring sheet 30 are connected. The electrode band 22 can be arranged and the detection wiring can be arranged by wrapping the electrode band 22 around the outer surface of the heat insulating material 12 in contact with the end portion of the electrode band 22.

As described above, when the wiring sheet 30 is used, a large number of electrode bands 22 can be arranged in the longitudinal direction of the refrigerant pipe 10 or at a plurality of connection points and welding points with a simpler configuration. Therefore, by using the wiring sheet 30, it is possible to detect the leakage of the refrigerant 11 and specify the leakage position with a simpler configuration.

In the above description, the electrode sheet assembly 20 is wound around the outer surface of the heat insulating material 12 of the refrigerant pipe 10 and installed. However, the electrode sheet assembly 20 is not wound around the outer surface of the heat insulating material 12 and installed, and the heat insulating material 12 is not installed. The leakage of the refrigerant 11 may be detected and the leakage position may be specified by movably winding the refrigerant pipe 10 around the outer surface of the refrigerant pipe 10 in the longitudinal direction and moving the electrode sheet assembly 20 in the longitudinal direction of the refrigerant pipe 10.

Next, the refrigerant leakage detection device 200 of another embodiment will be described with reference to FIGS. 4 to 9. The same parts as described above with reference to FIGS. 1 to 3 will be briefly described.

As shown in FIG. 4, the refrigerant leakage detection device 200 has the same configuration as the electrode sheet assembly 20 shown in FIG. 2A, and the circumferential length of the insulating sheet 41 is substantially the same as the outer peripheral length of the refrigerant pipe 10. The inner electrode sheet assembly 40 is formed with four inner electrode bands 42 to 45 formed on the inner electrode bands 42 to 45 with a gap in the longitudinal direction of the refrigerant pipe 10, and has the same configuration as the electrode sheet assembly 20 shown in FIG. 2 (a). On it, four outer electrode bands 52 to 55 include an outer electrode sheet assembly 50 formed with a gap in the longitudinal direction of the refrigerant pipe 10, a connection circuit 60, and a current detector 70.

As shown in FIG. 4, the inner electrode sheet assembly 40 and the outer electrode sheet assembly 50 are positioned so that the inner electrode bands 42 to 45 and the outer electrode bands 52 to 55 face each other with the heat insulating material 12 in between. As described above, the refrigerant pipe 14 and the heat insulating material 12 are wound around the outside. Therefore, the inner electrode bands 42 to 45 are substantially annular electrode bands wound around the outer periphery of the refrigerant pipe 10, and the outer electrode bands 52 to 55 are insulated so as to face the inner electrode bands 42 to 45. It is a substantially annular electrode band wound around the outer periphery of the material 12. Then, as shown in FIG. 6, the four inner electrode bands 42 to 45 and the four outer electrode bands 52 to 55 are four substantially annular capacitors having the same capacitance with the heat insulating material 12 sandwiched in the middle. It constitutes C1 to C4. As described above, the inner electrode bands 42 to 45 and the outer electrode bands 52 to 55 are electrode band sets constituting a plurality of capacitor sets arranged adjacent to each other in the longitudinal direction of the refrigerant pipe 10.

As shown in FIG. 5, in the connection circuit 60, four substantially annular capacitors C1 to C4 arranged side by side in the longitudinal direction of the refrigerant pipe 10 form one bridge circuit 80 as shown in FIG. It connects the four inner electrode bands 42 to 45 and the four outer electrode bands 52 to 55. As shown in FIGS. 5 and 6, in the connection circuit 60, the input terminals 61, 63, 65, 67 to which the four inner electrode bands 42 to 45 are connected, respectively, and the four outer electrode bands 52 to 55 are connected, respectively. The input terminals 62, 64, 66, and 68 are provided. Input terminals 61 and 65 are connected to input / output terminals 69a, input terminals 62 and 63 are connected to input / output terminals 69c, and input terminals 64 and 68 are connected to input / output terminals 69b by internal wiring. 67 is connected to the input / output terminal 69d. As a result, as shown in FIG. 6, the four inner electrode bands 42 to 45 and the four outer electrode bands 52 to 55 are opposed to each other by the connection circuit 60, and the inner electrode bands 42, the outer electrode bands 52, and the inner electrodes are opposed to each other. The band 43 and the outer electrode band 53, the inner electrode band 44 and the outer electrode band 54, and the inner electrode band 45 and the outer electrode band 55 each constitute one capacitor C1 to C4, and these four capacitors C1 to C4 are one. It is connected so as to form one bridge circuit 80.

Further, as shown in FIG. 5, the current detector 70 includes output terminals 73a and 73b to which an AC power supply 71 for supplying an AC current to the bridge circuit 80 is connected, and a current sensor 72 for detecting the current value between the terminals. It includes input terminals 73c and 73d to be connected. The electric circuit between the input terminals 73c and 73d to which the current sensor 72 is connected is a measurement electric circuit 75 for detecting the current flowing through the bridge circuit 80. When the output terminals 73a and 73b of the current detector 70 are connected to the input / output terminals 69a and 69d of the connection circuit 60, and the input terminals 73c and 73d of the current detector 70 are connected to the input / output terminals 69c and 69d of the connection circuit 60, As shown in FIG. 6, the current detector 70 supplies an AC current to the bridge circuit 80 by the AC power supply 71, and detects the current of the measurement electric circuit 75 of the bridge circuit 80 by the current sensor 72.

When there is no leakage of the refrigerant 11, the capacitances of the four capacitors C1 to C4 shown in FIG. 6 are the same capacitances calculated by the above equation (1). When the refrigerant 11 leaks, the refrigerant 11 enters the heat insulating material 12, so that the capacitance of the capacitor composed of the leaked inner electrode band and the outer electrode band is static electricity of the other three capacitors. It becomes larger than the electric capacity. Then, the equilibrium state of the bridge circuit 80 is broken, and a current flows through the measurement electric circuit 75. Therefore, the leakage of the refrigerant 11 can be detected by measuring the current value flowing through the measurement electric circuit 75 of the bridge circuit 80 with the current sensor 72.

In the refrigerant leakage detection device 200 of the present embodiment, the equilibrium state of the bridge circuit 80 is disrupted and a current flows due to a change in capacitance between the four capacitors C1 to C4 constituting the bridge circuit 80 due to leakage of the refrigerant 11. Is used. Therefore, even if the change in the capacitance of each of the capacitors C1 to C4 due to the presence or absence of leakage of the refrigerant 11 is small, the leakage of the refrigerant 11 can be reliably detected. Therefore, for example, even when the change in the capacity of the capacitors C1 to C4 due to the entry of the refrigerant 11 into the heat insulating material 12 is small when the refrigerant 11 is in a gaseous state, the leakage of the refrigerant 11 can be reliably detected. Further, when the liquid refrigerant 11 leaks, the change in the capacitance of the capacitors C1 to C4 becomes larger than when the gaseous refrigerant 11 leaks, and the current value detected by the current sensor 72 also becomes larger. Therefore, it is possible to determine whether the leaked refrigerant 11 is in a gas state or a liquid state based on the detected current value, and to estimate the amount of the leaked refrigerant 11.

As described above, the refrigerant leakage detection device 200 of the present embodiment has four substantially annular inner electrode bands 42 to 45 arranged on the outer periphery of the refrigerant pipe 10 and four substantially annular inner electrode bands 42 to 45 arranged on the outer periphery of the heat insulating material 12. The outer electrode bands 52 to 55 are arranged so as to form four substantially annular capacitors C1 to C4 having the same capacitance with the heat insulating material 12 sandwiched in the middle, and the four capacitors C1 to C4 are one bridge. The inner electrode bands 42 to 45 and the outer electrode bands 52 to 55 are connected so as to form the circuit 80, and the balance state of the bridge circuit 80 is lost due to the change in capacitance between the four capacitors C1 to C4, and the current is lost. Detects leakage of the refrigerant 11 due to the flow of As a result, the refrigerant leakage detection device 200 can detect the leakage of the refrigerant 11 with high sensitivity with a simple configuration.

In the refrigerant leakage detection device 200 of the embodiment described above, the leakage of the refrigerant 11 is detected by detecting the current flowing through the measurement electric circuit 75 of the bridge circuit 80 by the current sensor 72, but the balance of the bridge circuit 80 If it can be detected that a current is flowing through the measurement electric circuit 75 due to the collapse of the current sensor 72, leakage can be detected. Therefore, instead of the current sensor 72, an LED that emits light when a current of a predetermined value or more flows is arranged. The leakage of the refrigerant 11 may be detected by turning on and off the LED.

Further, in the refrigerant leakage detection device 200, the inner electrode sheet assembly 40 and the outer electrode sheet assembly 50 are located at positions where the inner electrode bands 42 to 45 and the outer electrode bands 52 to 55 face each other with the heat insulating material 12 interposed therebetween. Although it was explained that the refrigerant pipe 14 and the heat insulating material 12 are wound around the outside of the refrigerant pipe 14 and the heat insulating material 12, the four inner electrode bands 42 to 45 and the four outer electrode bands 52 to 55 sandwich the heat insulating material 12 in the middle. It is not limited to this configuration as long as it constitutes four substantially annular capacitors C1 to C4 having the same capacitance. For example, a laminate in which the heat insulating material 12 is sandwiched between the inner electrode sheet assembly 40 and the outer electrode sheet assembly 50 may be wound around the outer periphery of the refrigerant pipe 10.

The refrigerant leak detection device 200 described with reference to FIGS. 4 to 6 can detect that the refrigerant 11 has leaked at the place where it is installed, but it is in the length direction of the refrigerant pipe 10. It is difficult to detect where the refrigerant 11 is leaking. The refrigerant leakage detection device 300 shown in FIGS. 7 and 8 has four inner electrode bands 42 to 45 and the inner electrodes so as to form one bridge circuit 81 and 82 for each of the four capacitors C1 to C4 and C5 to C8. The four outer electrode bands 52 to 55 facing the bands 42 to 45, and the four inner electrode bands 142 to 145 and the four outer electrode bands 152 to 155 facing the inner electrode bands 142 to 145 are connected. be. Here, the inner electrode bands 142 to 145 and the outer electrode bands 152 to 155 are located at positions deviated from the positions where the inner electrode bands 42 to 45 and the outer electrode bands 52 to 55 are arranged in the longitudinal direction of the refrigerant pipe 10. Have been placed. The current detectors 70A and 70B have the same configuration as the current detector 70 described with reference to FIGS. 5 and 6, respectively, and include AC power supplies 71 and 171 and current sensors 72 and 172, respectively.

In FIG. 7, the inner electrode bands 42 to 45, the outer electrode bands 52 to 55, the current detector 70A, the inner electrode bands 42 to 45 in the connection circuit 60, the outer electrode bands 52 to 55, and the current detector 70A. The portion that makes the connection between the two constitutes the refrigerant leakage detection device 200 having the same configuration as described with reference to FIGS. 4 to 6. Further, in FIG. 7, the inner electrode band 142 to 145, the outer electrode band 152 to 155, the current detector 70B, the inner electrode band 142 to 145 in the connection circuit 60, the outer electrode band 152 to 155, and the current detector are shown. The portion to be connected to the 70B constitutes a refrigerant leakage detection device 210 having the same configuration as described with reference to FIGS. 4 to 6.

As described above, the inner electrode bands 142 to 145 and the outer electrode bands 152 to 155 are arranged in the longitudinal direction of the refrigerant pipe 10 from the positions where the inner electrode bands 42 to 45 and the outer electrode bands 52 to 55 are arranged. It is placed in a misaligned position. The inner electrode bands 142 to 145 and the outer electrode bands 152 to 155 may be arranged adjacent to the positions where the inner electrode bands 42 to 45 and the outer electrode bands 52 to 55 are arranged, or the inner electrode bands 42 to 42 to 45, the outer electrode bands 52 to 55 may be arranged at predetermined intervals along the longitudinal direction of the refrigerant pipe 10 from the arranged positions. Therefore, the refrigerant leakage detection device 300 shown in FIGS. 7 and 8 is the same as the refrigerant leakage detection device 200 described with reference to FIGS. 4 to 6 arranged side by side along the longitudinal direction of the refrigerant pipe 10. It is the composition of.

In the refrigerant leakage detection device 300, the leakage of the refrigerant 11 occurs at any of the refrigerant leakage detection devices 200 and 210 due to the increase in the current value of the current sensor of the refrigerant leakage detection device in which the leakage of the refrigerant 11 occurs. Can be identified if has occurred.

In the refrigerant leak detection device 300 described above, the two refrigerant leakage detection devices 200 have been described as being arranged side by side in the longitudinal direction of the refrigerant pipe 10, but not limited to two, a large number of refrigerant leakage detection devices 200 may be used. By arranging the refrigerant pipe 10 along the longitudinal direction, the location where the refrigerant 11 leaks can be specified in more detail. In this case, the location where the refrigerant leak detecting device 200 in which the current value detected by the current sensor becomes larger than a predetermined threshold value may be specified as the refrigerant leak occurrence location. The predetermined threshold value of the current value is the same as in the embodiment described above with reference to FIGS. 1 to 3, when the refrigerant 11 leaks in the liquid state, when the liquid refrigerant 11 leaks in the gaseous state, and when the liquid refrigerant 11 leaks in the gaseous state. When the liquid refrigerant 11 leaks with the refrigerating machine oil in a gaseous state, when the gaseous refrigerant 11 is flowing in the refrigerant pipe 10 and the gaseous refrigerant 11 leaks, the gaseous refrigerant 11 is the refrigerating machine oil. The value may be different depending on the case where the refrigerant 11 leaks with the refrigerating machine oil in a liquid state. For example, the predetermined threshold value for identifying the leakage occurrence location may be a different numerical value depending on the mode of the refrigerant 11. For example, in the section of the refrigerant pipe 10 through which the gaseous refrigerant 11 flows, the threshold may be smaller than the threshold in the section in which the liquid refrigerant 11 flows, and in the gas section, the ratio of refrigerating machine oil or the like leaking together with the gaseous refrigerant 11 A threshold calculated based on the permittivity may be used.

As described above, the refrigerant leakage detection device 300 of the present embodiment has the same effect as the refrigerant leakage detection device 200 described above, and can identify the leakage occurrence location of the refrigerant 11 with a simple configuration.

Next, the refrigerant leakage detection device 400 of another embodiment will be described with reference to FIG. The refrigerant leakage detection device 400 shown in FIG. 9 has an inner electrode band assembly and an outer electrode constituting the bridge circuits 81 and 82 inside the connection circuit 60 of the refrigerant leakage detection device 300 described with reference to FIGS. 7 and 8. It is provided with a connection switch 90 for sequentially shifting the combination of bands along the longitudinal direction of the refrigerant pipe 10.

As shown in FIG. 9A, in the connection switch 90, the capacitors C1 to C4 are initially formed by the inner electrode bands 42 to 45 and the outer electrode bands 52 to 55, and the inner electrode bands 143 to 145 and the outer electrode bands 152 are formed. The inner electrode bands 42 to 45, 142 to 145, the outer electrode bands 52 to 55, 152 to 155 and the input terminals 61 to 68, 161 to 168 are connected so as to form the capacitors C5 to C8 by ~ 155. There is. Next, in the connection switching device 90, the inner electrode band 42 and the outer electrode band 52 are connected to the inner electrode band 43 and the outer electrode band 53 adjacent to the input terminals 61 and 62 along the longitudinal direction of the refrigerant pipe 10 of the outer electrode band 52. The connection is switched so that the electrode band 43 and the outer electrode band 53 form the capacitor C1. As a result, as shown in FIG. 9B, the capacitors C1 to C4 are formed by the inner electrode bands 43 to 45, 142 and the outer electrode bands 53 to 55, 152, and the inner electrode bands 143 to 145, 242 and the outer electrodes. The inner electrode bands 43 to 45, 142, 143 to 145, 242, the outer electrode bands 53 to 55, 152, 153 to 155, 252 and the input terminals so that the capacitors C5 to C8 are formed by the bands 153 to 155 and 252. 61 to 68 and 161 to 168 are connected. Here, the inner electrode band 242 and the outer electrode band 252 are electrode bands included in another refrigerant leakage detection device 220 arranged in the longitudinal direction of the refrigerant pipe 10 of the refrigerant leakage detection device 210 shown in FIG. 9A. be.

As a result, in the refrigerant leakage detection device 200, the inner electrode bands 43 to 45, 142, the outer electrode bands 53 to 55, 152, which are displaced in the longitudinal direction of the refrigerant pipe 10 from the beginning, and the inner electrode band 143 are arranged. It is possible to detect leakage of the refrigerant 11 in the regions where ~ 145, 242 and the outer electrode bands 153 to 155, 252 are arranged.

As described above, the refrigerant leakage detection device 400 of the present embodiment sets the inner electrode band and the outer electrode band constituting the bridge circuits 81 and 82 along the longitudinal direction of the refrigerant pipe 10 along the longitudinal direction of the refrigerant pipe 10. Therefore, even if the number of connection circuits 60, current detectors 70A, and 70B is small, it is possible to detect refrigerant leakage in a wide range of the refrigerant pipe 10.

The connection switch 90 of the refrigerant leakage detection device 400 described above sets the eight inner electrode bands and the eight outer electrode bands constituting the bridge circuits 81 and 82 along the longitudinal direction of the refrigerant pipe 10 of the refrigerant pipe 10. Although it has been described that the refrigerant pipes are sequentially shifted along the longitudinal direction, a larger number of inner electrode bands and outer electrode bands are arranged along the longitudinal direction of the refrigerant pipe 10, and the connection switcher is referred to with reference to FIGS. 5 and 6. The set of the four inner electrode bands and the four outer electrode bands constituting the bridge circuit 80 as described above may be configured to be sequentially shifted along the longitudinal direction of the refrigerant pipe 10. In this case, since the refrigerant leakage detection device can be configured by one current detector, it is possible to detect the refrigerant leakage in a wide range of the refrigerant pipe 10 with a simpler configuration.

Next, the refrigerant leakage detection system 500 of the embodiment will be described with reference to FIGS. 10 and 11. The same parts as those in the embodiment described above with reference to FIGS. 1 to 3 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 10, the refrigerant leakage detection system 500 of the present embodiment detects the leakage occurrence location of the refrigerant pipe 610 connecting a plurality of air conditioning equipment installed in the building 600. As shown in FIG. 10, an air conditioner outdoor unit 604 is installed on the roof of the building 600, and cold air or hot air is used in the room on each floor by the cooling or heating refrigerant 11 from the outdoor unit 604. The indoor units 601 to 603 for supplying the above are installed. The indoor units 601 to 603 and the outdoor unit 604 on each floor are connected by a refrigerant pipe 610. The refrigerant pipe 610 is composed of a refrigerant pipe 605 to 608 of each floor arranged on each floor and a vertical pipe 609 connecting the refrigerant pipes 605 to 608 of each floor in the height direction.

As shown in FIG. 11, a heat insulating material 12 is wound around the outer surface of the refrigerant pipe 610 as in the embodiment described with reference to FIG. 1, and the outer periphery of the heat insulating material 12 is placed on the insulating sheet 21. An electrode sheet assembly 20 to which a plurality of metal thin film electrode bands 22 are attached is wound. The width L of the electrode band 22 is about 100 mm as in the embodiment described with reference to FIGS. 1 to 3, and a plurality of electrode bands 22 are arranged in the longitudinal direction of the refrigerant pipe 610 at a pitch P of, for example, about 1 m. Has been done. The plurality of electrode bands 22 form an electrode band assembly.

Each electrode band 22 is connected to the selector 501. The selector 501 connects one of the plurality of connected electrode bands 22 to the capacitance meter 25. Further, the refrigerant pipe 610 is connected to the capacitance meter 25. Then, by sequentially selecting the predetermined electrode band 22 by the selector 501, the predetermined electrode band 22 and the refrigerant pipe are formed in the same manner as the refrigerant leakage detection device 100 of the embodiment described with reference to FIGS. 1 to 3. The capacitance between 610 and 610 can be measured sequentially.

In the refrigerant leakage detection system 500 of the present embodiment, the electrode sheet assembly 20 is attached along the refrigerant pipes 605 to 608 and the vertical pipe 609 on each floor, and the selector 501 sequentially performs capacitance between the predetermined electrode band 22 and the refrigerant pipe 610. Since the capacitance is measured sequentially, it is possible to effectively detect the leakage occurrence location of the refrigerant 11. The predetermined threshold value of the capacitance for identifying the leakage occurrence location is the same as in the embodiment described above with reference to FIGS. 1 to 3, when the liquid refrigerant 11 leaks in the liquid state, the liquid refrigerant 11 is used. When the liquid refrigerant 11 leaks in the gaseous state, when the refrigerating machine oil leaks in the gaseous state, when the gaseous refrigerant 11 is flowing in the refrigerant pipe 10 and the gaseous refrigerant 11 leaks, When the gaseous refrigerant 11 leaks with the refrigerating machine oil, the value may be different depending on the case where the refrigerant 11 leaks with the refrigerating machine oil in the liquid state. For example, the predetermined threshold value for identifying the leakage occurrence location may be a different numerical value depending on the mode of the refrigerant 11. For example, in the section of the refrigerant pipe 10 through which the gaseous refrigerant 11 flows, the threshold may be smaller than the threshold in the section in which the liquid refrigerant 11 flows, and in the gas section, the ratio of refrigerating machine oil or the like leaking together with the gaseous refrigerant 11 A threshold calculated based on the permittivity may be used.

Further, in the present embodiment, the electrode sheet assembly 20 is arranged along the refrigerant pipes 605 to 608 and the vertical pipes 609 on each floor, but as shown in FIG. 12, the width L of the electrode band 22 is the same. The electrode sheet assembly 20 having a width of about 100 mm may be arranged at a pitch P of about 1 m.

10 Refrigerator pipe, 11 Refrigerator, 12 Insulation material, 20 Electrode sheet assembly, 21, 41, 51 Insulation sheet, 22 Electrode band, 23 Output terminal, 24, 32 Wiring, 25 Capacitometer, 30 Wiring sheet, 31 Insulation sheet , 33, 34 terminals, 40 inner electrode sheet assembly, 42-45, 142-145 inner electrode band, 50 outer electrode sheet assembly, 52-55, 152-155 outer electrode band, 60 connection circuit, 61-68 input terminals, 69a to 69d input / output terminals, 70, 70A, 70B current detectors, 71, 171 AC power supplies, 72, 172 current sensors, 73a, 73b output terminals, 73c, 73d input terminals, 75 measurement wires, 80, 81, 82 bridges Circuit, 90 connection switch, 100, 200, 210, 220, 300, 400 Refrigerator leak detector, 500 Refrigerator leak detection system, 501 selector, 600 building, 601 to 603 indoor unit, 604 outdoor unit, 605 to 608,610 Refrigerator pipe, 609 vertical pipe.

Claims (16)

And the electrode strip is a substantially annular metal thin film wound around the outer periphery of the heat insulator covering the outer surface of the metallic refrigerant tube in which the refrigerant flows, based on the capacitance between the refrigerant tube, from the refrigerant tube A refrigerant leak detection device that detects refrigerant leaks.
The metal thin film of the electrode band is formed so as to extend in the winding direction on a flexible insulating sheet wound around the outer periphery of the heat insulating material.
A refrigerant leak detection device characterized by. The refrigerant leakage detection device according to claim 1.
A plurality of electrode band sets in which the electrode bands are arranged with a gap along the longitudinal direction of the refrigerant pipe are provided.
Each capacitance between each of the electrode bands and the refrigerant pipe is measured, and a region where the electrode band is arranged where a capacitance larger than a predetermined threshold value is detected is set as a refrigerant leakage occurrence location .
A refrigerant leak detection device characterized by. The refrigerant leakage detection device according to claim 1.
The insulating sheet includes a wiring that connects an end portion in a direction perpendicular to the winding direction and the electrode band, and the wiring is a linear metal thin film formed on the insulating sheet .
A refrigerant leak detection device characterized by. It is a refrigerant leak detection method that detects the leakage of refrigerant from the metal refrigerant pipe through which the refrigerant flows.
An electrode band which is a substantially annular metal thin film wound around the outer periphery of the heat insulating material covering the outer surface of the refrigerant pipe, and the winding direction of the metal thin film on a flexible insulating sheet wrapped around the outer periphery of the heat insulating material. Prepare an electrode band assembly in which a plurality of electrode bands formed so as to extend to the above are arranged with a gap along the longitudinal direction of the refrigerant pipe.
Each capacitance between each of the electrode bands and the refrigerant pipe is measured, and a region where the electrode band is arranged where a capacitance larger than a predetermined threshold value is detected is set as a refrigerant leakage occurrence location .
Refrigerant leakage detection method characterized by. It is a refrigerant leak detection device that detects the leakage of refrigerant from the metal refrigerant pipe through which the refrigerant flows.
A substantially annular inner electrode band wound around the outer periphery of the refrigerant pipe, and each of the inner electrode bands wrapped around the outer periphery of the heat insulating material covering the outer surface of the inner electrode band so as to face the inner electrode band. A plurality of substantially annular outer electrode bands forming a capacitor between them are arranged with a gap along the longitudinal direction of the refrigerant pipe to form a plurality of sets of capacitors arranged along the longitudinal direction of the refrigerant pipe. Equipped with a set of electrode bands
Refrigerant leakage is detected based on the change in capacitance between each capacitor formed by the electrode band assembly.
The inner electrode band is a metal thin film formed so as to extend in the winding direction on a flexible inner insulating sheet wound around the outer periphery of the refrigerant pipe.
The outer electrode band is a metal thin film formed so as to extend in the winding direction on a flexible outer insulating sheet wound around the outer periphery of the heat insulating material covering the outer surface of the inner electrode band.
A refrigerant leak detection device characterized by. The refrigerant leakage detection device according to claim 5.
Among the plurality of capacitors formed by the electrode band assembly, the four capacitors adjacent to each other in the longitudinal direction of the refrigerant pipe face the inner electrode band and the inner electrode band so as to form one bridge circuit. A connection circuit that connects the four outer electrode bands and
A current detector for supplying a current to the bridge circuit configured by the connection circuit and detecting a current value flowing in a measurement electric circuit of the bridge circuit is provided.
To detect refrigerant leakage based on the magnitude of the current value detected by the current detector .
A refrigerant leak detection device characterized by. The refrigerant leakage detection device according to claim 5.
Of the plurality of capacitors formed by the electrode band assembly, the four inner electrode bands and the inner electrode bands face each other so as to form one bridge circuit for each of the four capacitors adjacent in the longitudinal direction of the refrigerant pipe. A connection circuit that connects a plurality of sets of the four outer electrode bands to form a plurality of the bridge circuits arranged in the longitudinal direction of the refrigerant pipe, and a connection circuit.
Each current detector that supplies a current to each of the bridge circuits configured by the connection circuit and detects each current value flowing in each measurement electric circuit of each of the bridge circuits is provided.
The region where the inner electrode band and the outer electrode band constituting the bridge circuit to which the current detector that has detected a current larger than a predetermined threshold value is connected is set as a refrigerant leakage occurrence location .
A refrigerant leak detection device characterized by. The refrigerant leakage detection device according to claim 6 or 7.
The connection circuit includes four inner electrode bands and the inner electrode bands that are connected to the connection circuit so as to sequentially shift a set of four capacitors constituting one bridge circuit in the longitudinal direction of the refrigerant pipe. The set of the four facing outer electrode bands is sequentially shifted in the longitudinal direction of the refrigerant pipe .
A refrigerant leak detection device characterized by. The refrigerant leakage detection device according to claim 5.
The inner insulating sheet and the outer insulating sheet include a wiring connecting an end portion in a direction perpendicular to the winding direction and the inner electrode band or the outer electrode band, respectively, and the wiring is on the inner insulating sheet or said. Being a linear metal thin film formed on the outer insulating sheet ,
A refrigerant leak detection device characterized by. It is a refrigerant leak detection method that detects the leakage of refrigerant from the metal refrigerant pipe through which the refrigerant flows.
The inner side electrode strips substantially annular composed of a metal thin film formed so as to extend in the winding direction on the inner insulating sheet of flexible that wound on the outer periphery of said coolant tube, the outer surface of the inner electrode strip formed of a metal thin film formed so as to extend in the winding direction on the outer insulating sheet of flexible that is wound around the outer circumference of the heat insulating material covering the, with the inner electrode strip and opposite to each of said inner electrode strip an outer side electrode strips substantially annular forming a capacitor between, with a gap respectively along the longitudinal direction of the refrigerant pipe and a plurality arranged a plurality of capacitors sets aligned along the longitudinal direction of the refrigerant pipe Prepare the electrode band set to be formed,
To detect refrigerant leakage based on the change in capacitance between each capacitor formed by the electrode band assembly .
Refrigerant leakage detection method characterized by. The refrigerant leakage detection method according to claim 10.
Among the plurality of capacitors formed by the electrode band assembly, the four capacitors adjacent to each other in the longitudinal direction of the refrigerant pipe face the inner electrode band and the inner electrode band so as to form one bridge circuit. four connecting the outer electrode strips,
While supplying a current to the bridge circuit, the current value flowing through the measurement electric circuit of the bridge circuit is detected.
Detecting refrigerant leakage based on the magnitude of the detected current value ,
Refrigerant leakage detection method characterized by. The refrigerant leakage detection device according to claim 2.
Setting the predetermined threshold value to a numerical value that differs depending on the mode of the refrigerant.
A refrigerant leak detection device characterized by. The refrigerant leakage detection method according to claim 4.
Setting the predetermined threshold value to a numerical value that differs depending on the mode of the refrigerant.
Refrigerant leakage detection method characterized by. The refrigerant leakage detection device according to claim 7.
Setting the predetermined threshold value to a numerical value that differs depending on the mode of the refrigerant.
A refrigerant leak detection device characterized by. It is a refrigerant leak detection system that identifies the location where the refrigerant leaks from the metal refrigerant pipe through which the refrigerant flows.
Includes an electrode band set in which a plurality of electrode bands, which are substantially annular metal thin films wound around the outer periphery of a heat insulating material covering the outer surface of the refrigerant pipe, are arranged with a gap along the longitudinal direction of the refrigerant pipe.
The metal thin film of the electrode band is formed so as to extend in the winding direction on a flexible insulating sheet that is wound around the outer periphery of the heat insulating material.
Be a leakage occurrence point of the refrigerant placement area of the electrode strip that has detected the higher capacitance than sequentially measured, a predetermined threshold value the capacitance between the refrigerant tube and each of said electrode strip ,
Refrigerant leak detection system featuring. The refrigerant leakage detection system according to claim 15.
Setting the predetermined threshold value to a numerical value that differs depending on the mode of the refrigerant.
Refrigerant leak detection system featuring.

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