JP2004271086A - Heat transfer pipe failure detecting device and heat storage device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat transfer pipe failure detecting device for finding the failure of a heat transfer pipe earlier without stopping operation, and a heat storage device equipped therewith. <P>SOLUTION: The heat storage device 11 comprises a detection chamber 31 provided outside an outer case 23, a temperature sensor 32 for detecting a temperature in the detection chamber 31, and a control device 51 for determining whether the heat transfer pipe 25 is failed or not in accordance with the temperature in the detection chamber 31 detected by the temperature sensor 32. Heat carrier vapor generated in an inner case 21 is guided via a vapor lead-out pipe 41 to the detection chamber 31. When the temperature in the detection chamber 31 reaches a heat transfer pipe failure determining temperature, the control device 51 determines that the heat transfer pipe 25 is failed. The failure of the heat transfer pipe 25 is therefor found earlier. The failure of the heat transfer pipe 25 can be detected without stopping the operation of the heat storage device 11 or emptying the heat transfer pipe 25 once. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat transfer tube damage detection device for detecting damage to a heat transfer tube through which a heat medium flows, and a heat storage device including the same.
[0002]
[Prior art]
Conventionally, the following heat storage devices are known. That is, the heat storage material filled in the case is heated by a heater, and in this state, water is supplied from one of the heat transfer tubes buried in the heat storage material by driving a pump, and the water is taken out from the other as steam (for example, see Patent Document 1). 1). In this conventional heat storage device, inspection for confirming the presence or absence of heat transfer tube damage (pinhole, pitting corrosion, stress corrosion cracking, etc.) due to aging deterioration and manufacturing defects, etc. is performed periodically (every three months or every six months). ) Has been done. As a method of the periodic inspection, for example, there are a method of injecting pressurized air into the heat transfer tube and a method of manually collecting and analyzing water in the heat transfer tube.
[0003]
In the former case, if the heat transfer tube is damaged, the injected air leaks from the damaged portion. In the latter case, for example, the component of the collected water is analyzed and compared with the component of the water before passing through the heat transfer tube. If the heat storage material component is included in the collected water component, it is determined that any part of the heat transfer tube is damaged. This is because when the heat transfer tube is damaged, the water-soluble nitrate constituting the heat storage material elutes into the water flowing in the heat transfer tube.
[0004]
[Patent Document 1]
JP-A-3-282101
[Problems to be solved by the invention]
However, the conventional heat storage device has the following problems. That is, although the heat transfer tube was regularly inspected, if the heat transfer tube is damaged by pitting or the like for some reason after this periodic inspection, the heat transfer tube is left in a broken state until the next periodic inspection. There was a fear. That is, it was difficult to detect the damage of the heat transfer tube at an early stage. Further, in the conventional method for inspecting a heat transfer tube for damage, it was necessary to stop the operation of the heat storage device or to empty the heat transfer tube once. For this reason, even if the heat transfer tube is damaged during operation of the apparatus, this is not immediately detected.
[0006]
The present invention has been made to solve the above problems, and an object of the present invention is to provide a heat transfer tube damage detection device capable of detecting damage to a heat transfer tube at an early stage without stopping operation, and a device for detecting the damage. An object of the present invention is to provide a heat storage device.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a heat transfer tube damage detection device that is disposed in a case and has a heat medium flowing therein, and detects damage to a heat transfer tube that exchanges heat between the heat medium and the heat source. A steam detection unit provided outside the case and capable of detecting the heat medium vapor generated in the case, and a communication path for guiding the heat medium vapor generated in the case to the steam detection unit. The gist of the invention is that when detecting the heat medium vapor from the communication passage, the vapor detection unit determines that the heat transfer tube is damaged.
[0008]
According to a second aspect of the present invention, in the first aspect of the invention, in the case, the steam detector is disposed on a side of the case opposite to an outlet side of both ends of the heat transfer tube. I do.
[0009]
According to a third aspect of the present invention, in the first or second aspect of the invention, the steam detection unit includes a detection chamber provided outside the case and a temperature detection unit configured to detect a temperature in the detection chamber. Means, and judging means for judging the presence or absence of breakage of the heat transfer tube based on the temperature in the detection chamber detected by the temperature detecting means, the communication path between the inside of the case and the inside of the detection chamber The point is that the communication is made.
[0010]
According to a fourth aspect of the present invention, in the third aspect, an upper portion of the detection chamber is closed, and an opening is provided in the lower portion.
According to a fifth aspect of the present invention, there is provided an electric heater for heating a heat storage material filled in a case, and a heat medium disposed in the case and having a heat medium flow therein to allow the heat medium to flow between the heat medium and the heat storage material. In a heat storage device provided with a heat transfer tube for performing heat exchange, a heat transfer tube damage detection device according to any one of claims 1 to 4 is provided.
[0011]
(Action)
According to the first aspect of the present invention, the heat medium vapor generated in the case due to, for example, breakage of the heat transfer tube is guided to the vapor detection unit provided outside the case via the communication path. The steam detecting section detects that the heat transfer tube is broken by detecting the heat medium steam. For this reason, the breakage of the heat transfer tube can always be detected during the operation without stopping the operation.
[0012]
According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, in the case, the steam detection unit is disposed on a side of the heat transfer tube opposite to an outlet side of both ends. . For this reason, the steam detector is not affected by the temperature due to the heat radiation from the outlet of the heat transfer tube. Therefore, erroneous detection by the steam detector is suppressed.
[0013]
According to the third aspect of the invention, in addition to the operation of the first or second aspect, the heat medium vapor generated in the case is detected outside the case via the communication passage. Guided to the room. The temperature in the detection chamber is detected by the temperature detection means, and the presence or absence of breakage of the heat transfer tube is determined based on the temperature in the detection chamber detected by the temperature detection means.
[0014]
According to the invention described in claim 4, in addition to the effect of the invention described in claim 3, the upper part of the detection chamber is closed and the lower part is also opened. Since the opening of the detection chamber is located below, it is difficult for steam leaking from the inside of the case to escape from the detection chamber, and the steam is trapped in the detection chamber. Therefore, the temperature detected by the temperature detecting means is maintained in the peak state for a predetermined time. Further, even when the amount of the leaked steam is small, the leaked steam is trapped in the detection chamber, so that the temperature in the detection chamber gradually increases to reach a peak value and is maintained for a predetermined time.
[0015]
According to the invention described in claim 5, the heat storage device is provided with the heat transfer tube damage detection device according to any one of claims 1 to 4. Therefore, it is possible to detect breakage of the heat transfer tube without stopping the operation.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a heat transfer tube damage detection device and a heat storage device including the same will be described with reference to FIGS.
[0017]
As shown in FIG. 1, the inner case 21 constituting the heat storage device 11 is housed in the outer case 23 with the entire outer periphery thereof covered with a heat insulating material 22. A space S1 is formed by the upper surface of the heat insulating material 22 disposed on the upper surface of the inner case 21 and the inner surface of the outer case 23. The inner case 21 is filled with solid magnesia and a heat storage material 24 mainly composed of nitrate which is liquefied in a predetermined heat storage temperature region (only a part is shown in FIG. 1).
[0018]
The inner case 21 includes a box-shaped inner case main body 21a having an open upper part and a box-shaped lid 21b for closing the upper opening of the inner case main body 21a. The upper surface of the heat storage material 24 filled in the inner case body 21a, the inner surface of the inner case body 21a, and the lid 21b form a margin space S2. Volume expansion accompanying the melting of nitrate at the start of heat storage (at the time of initial startup) is allowed by the surplus space S2. A spiral heat transfer tube 25 through which a heat medium (water in the present embodiment) flows, and a U-shaped electric heater 26 for heating the heat storage material 24 are provided in the inner case main body 21a.
[0019]
Both ends of the heat transfer tube 25 are water-tightly penetrated through the lid 21 b of the inner case 21, the heat insulating material 22, and the upper side wall of the outer case 23, and are led out to the outside. Both ends of the heat transfer tube 25 pass through one side wall (the left side wall in FIG. 1) of the outer case 23 and are led out in the same direction. One end of the heat transfer tube 25 is connected to a water source (not shown) via a water supply line 27, and a water supply pump 28 is provided on the water supply line 27. The other end of the heat transfer tube 25 is guided to a load side via a steam supply tube 29. Both ends of the electric heater 26 penetrate the lid 21b of the inner case 21 and the heat insulating material 22 on the upper part in a watertight manner, and are led out into the spare space S2. Both ends of the electric heater 26 are connected to an AC power supply (not shown) via lead wires (not shown).
[0020]
As shown in FIG. 1, the outer case 23 includes an outer case main body 23a having an open upper part, and a lid 23b for closing an upper opening of the outer case main body 23a. Side walls are provided on the four sides of the lid 23b, and a square cylindrical detection chamber 31 is provided at the center of the side wall of each side wall opposite to the direction in which both ends of the heat transfer tube 25 are led out. I have. That is, the side wall of the outer case 23 on the lid 23b side in the detection chamber 31 forms a part of the side wall of the lid 23b. The upper part of the detection chamber 31 is closed, and the lower part is formed with an opening 31a. The upper part of the detection chamber 31 protrudes above the upper surface of the lid 23b. A temperature sensor 32 is provided on the upper side of the detection chamber 31, and a detection end 32 a is introduced into the detection chamber 31.
[0021]
As shown in FIG. 1, one end of a steam outlet pipe 41 is connected to the lid 21 b of the inner case 21, and the other end of the steam outlet pipe 41 penetrates the upper heat insulating material 22 in a water-tight manner and is connected to the outside. It is introduced into the extra space S2 of the case 23. The other end of the steam outlet pipe 41 penetrates through the upper part of the side wall of the outer case body 23a and the side wall of the lid 23b in the outer case 23, and is connected to the lower part of the detection chamber 31. Is communicated with the inside through a steam outlet pipe 41.
[0022]
As shown in FIG. 1, the heat storage device 11 includes a control device 51 including a CPU and the like. The control device 51 determines whether or not steam is leaking from the heat transfer tube 25 based on the ambient temperature in the detection chamber 31 detected by the temperature sensor 32, that is, determines whether or not the heat transfer tube 25 is damaged. Further, the control device 51 performs various controls such as on / off control of the electric heater 26, drive / stop control of the water supply pump 28, and display control of breakage of the heat transfer tube 25 based on a control program incorporated in advance.
[0023]
In the present embodiment, the detection chamber 31, the temperature sensor 32, and the steam outlet pipe 41 constitute a heat transfer tube damage detection device D. The detection chamber 31, the temperature sensor 32, and the control device 51 constitute a steam detection unit that detects the heat medium steam generated in the inner case 21. The steam outlet pipe 41 forms a communication path that connects the inside of the inner case 21 and the inside of the detection chamber 31. The temperature sensor 32 constitutes temperature detecting means for detecting the temperature inside the detection chamber 31. The inner case 21 constitutes a case filled with the heat storage material 24.
[0024]
[Operation of Embodiment]
Next, the operation of the heat transfer tube breakage detection device and the heat storage device configured as described above will be described sequentially for normal times and abnormal times. The normal state refers to a heat output operation in a state where the heat transfer tube 25 is not damaged and no steam leaks. The abnormal time refers to a time when the heat transfer operation is performed in a state where the heat transfer tube 25 is damaged and steam leaks.
[0025]
[Normal]
First, the operation of the heat transfer tube damage detection device D and the heat storage device 11 during normal operation (during normal operation) will be described. The heat output operation of the heat storage device 11 is started in a state where the heat storage material 24 is heated to a predetermined heat storage temperature (about 450 ° C. in the present embodiment) by, for example, heating the electric heater 26 by nighttime electric power. That is, the heat medium (water) is supplied from one end of the heat transfer tube 25 by driving the water supply pump 28. Then, the water is heated by the heat stored in the heat storage material 24 via the heat transfer tubes 25, and is spouted from the other of the heat transfer tubes 25 as steam. In this way, the heat stored in the heat transfer tube 25 is taken out.
[0026]
The high-temperature atmosphere gas in the inner case 21, that is, the hot air (hot air) rising from the heat storage material 24 flows into the detection chamber 31 through the steam outlet pipe 41. A part of this hot air is discharged to the outside from the opening 31a at the lower part of the detection chamber 31, and the rest is trapped at the upper part in the detection chamber 31. In a normal state, the hot air from the inside of the inner case 21 radiates heat through the steam outlet pipe 41 and the lid 23b of the outer case 23, and to some extent before reaching the inside of the detection chamber 31 (a predetermined heat transfer tube damage judgment). (Less than the temperature Ts). Therefore, in this normal state, the temperature detected by the temperature sensor 32 does not reach the preset heat transfer tube damage determination temperature Ts. When the temperature detected by the temperature sensor 32 is lower than the heat transfer tube damage determination temperature Ts, the control device 51 determines that steam has leaked from the heat transfer tube 25, that is, the heat transfer tube 25 has not been damaged.
[0027]
[In case of abnormality]
Next, the operation of the heat transfer tube damage detection device D and the heat storage device 11 at the time of abnormality will be described. The heat transfer tube 25 may be damaged (for example, pinholes or stress corrosion cracking) due to aging deterioration and manufacturing defects. In this case, although depending on the degree of damage, water or steam flowing through the heat transfer tube 25 leaks into the heat storage material 24 from the damaged portion of the heat transfer tube 25. The water leaked into the heat storage material 24 becomes steam by the heat of the heat storage material 24. These vapors rise inside the heat storage material 24 (strictly between magnesia) and flow into the extra space S2 in the inner case 21.
[0028]
Steam leaking from the inner case 21 flows into the detection chamber 31 through the steam outlet pipe 41 and reaches the detection end of the temperature sensor 32. The leaked steam cannot completely dissipate heat until it reaches the inside of the detection chamber 31, and reaches the detection end 32a of the temperature sensor 32 in a state where the leaked steam has a temperature equal to or higher than the heat transfer tube damage determination temperature Ts. As a result, the temperature detected by the temperature sensor 32 reaches the heat transfer tube damage determination temperature Ts.
[0029]
At this time, since the upper part of the detection chamber 31 is closed, a part of the steam leaking from the inside of the inner case 21 stays in the upper part of the detection chamber 31. The detection end of the temperature sensor 32 is provided on the opposite side of the opening 31 a of the detection chamber 31, that is, on the upper side, so that the temperature sensor 32 detects the temperature of the leaked steam trapped in the detection chamber 31. It will be.
[0030]
Therefore, the temperature detected by the temperature sensor 32 is maintained at the peak state for a predetermined time. That is, the peak value duration of the temperature detected by the temperature sensor 32 is secured. Therefore, even if the temperature detected by the temperature sensor 32 instantaneously reaches the peak value, the control device 51 does not perform the abnormality determination, and confusion with the noise of the temperature sensor 32 can be avoided. Since the lower part of the detection chamber 31 is open, there is no possibility that steam leaking from the inner case 21 is condensed and accumulated in the detection chamber 31.
[0031]
Further, the temperature sensor 32 does not detect a sudden rise of the detection value, and does not detect the peak value every time steam is generated. Incidentally, when the steam leaking from the inner case 21 is directly received by the temperature sensor 32, the temperature sensor 32 detects a rapid rise of the detected value and detects a peak value every time steam is generated.
[0032]
That is, the heat transfer tube 25 is damaged, and the heat medium leaked from the damaged portion becomes vapor and explosively released to the detection chamber 31. However, after this, the heat storage material 24 around the broken portion of the heat transfer tube 25 is cooled by the heat medium on the contrary, blocking the leak path, and the discharge of the heat medium vapor stops. Therefore, the peak value is not maintained. Thereafter, the heat storage material 24 around the broken portion of the heat transfer tube 25 is heated and liquefied again by the heat of the heat storage material 24 around the heat storage material 24 being transferred. Then, the steam ejection path is formed again, and the heat medium steam is ejected again. Then, the detection value of the temperature sensor 32 reaches the peak value again. Therefore, the peak value maintenance time is short, and a stable detection operation cannot be obtained. According to the present embodiment, since such a situation is avoided, the detection operation of the temperature sensor 32 is stabilized.
[0033]
Further, even when the degree of breakage of the heat transfer tube 25 is small and the amount of leaked steam from the inside of the inner case 21 is small, the leaked steam having a temperature higher than the normal temperature of the high-temperature atmosphere gas is continuously generated. The temperature in the detection chamber 31 gradually increases due to the leakage and the confinement in the detection chamber 31. The temperature of the leaked steam reaches the detection chamber without radiating heat. Then, although a certain time is required, the detected temperature in the detection chamber 31 reaches a peak value and is maintained for a predetermined time. As described above, the predetermined detection condition (in the present embodiment, the temperature in the detection chamber 31 reaches the heat transfer tube damage determination temperature Ts) due to the accumulation of the steam leaking from the inner case 21 in the detection chamber 31. Is satisfied. Therefore, regardless of the amount of steam leaking from the inner case 21, an abnormal state (that is, breakage of the heat transfer tube) can be reliably detected.
[0034]
As described above, when the temperature in the detection chamber 31 detected by the temperature sensor 32 reaches the preset heat transfer tube damage determination temperature Ts, the control device 51 detects a steam leak from the inner case 21. That is, the control device 51 determines that the heat transfer tube 25 is damaged. Then, the control device 51 outputs a heat transfer tube breakage signal to abnormality notification means (not shown) such as an LED (light emitting diode), a display, and a speaker.
[0035]
(Effects of the embodiment)
Therefore, according to the present embodiment, the following effects can be obtained.
(1) A steam detector provided outside the inner case 21 and capable of detecting the heat medium vapor generated in the inner case 21, and guiding the heat medium vapor generated in the inner case 21 to the steam detector. And a steam outlet pipe 41. Then, it is determined that the heat transfer tube 25 is damaged when the heat medium steam is detected by the steam detection unit.
[0036]
Specifically, the steam detection unit includes a detection chamber 31 provided outside the inner case 21 (strictly, the outer case 23), a temperature sensor 32 for detecting the temperature in the detection chamber 31, and a temperature sensor 32. And a controller 51 for determining whether or not the heat transfer tube 25 is damaged based on the temperature in the detection chamber 31 detected by the control unit 51. The heat medium vapor generated in the inner case 21 is guided to the detection chamber 31 via the vapor discharge pipe 41, and when the temperature in the detection chamber 31 reaches the heat transfer pipe breakage determination temperature Ts, the control device 51 transmits the heat transfer pipe. 25 is determined to be damaged.
[0037]
Therefore, when the heat transfer tube 25 is damaged for some reason, the damage of the heat transfer tube 25 can be found at an early stage, and the heat transfer tube 25 is not left in a damaged state until the next periodic inspection. Further, the breakage of the heat transfer tube 25 can be detected without stopping the operation of the heat storage device 11 or once emptying the heat transfer tube 25. For this reason, the breakage of the heat transfer tube 25 can be always detected during the operation without stopping the operation of the heat storage device 11. Therefore, if the heat transfer tube 25 is damaged during the operation of the heat storage device 11, it can be detected immediately.
[0038]
(2) The steam detection section is arranged on the opposite side of the both ends of the heat transfer tube 25 from the outlet side. Specifically, the detection chamber 31 is arranged on the opposite side of the direction in which both ends of the heat transfer tube 25 are led out. Therefore, the temperature sensor 32 provided in the detection chamber 31 is not affected by an increase in the ambient temperature due to heat radiation from the outlet of the heat transfer tube 25. Therefore, erroneous detection of leaked steam is suppressed, and the presence or absence of breakage of the heat transfer tube 25 can be more accurately detected.
[0039]
(3) The upper part of the detection chamber 31 was closed, and the lower part was provided with an opening 31a. Then, the temperature sensor 32 is arranged on the opposite side of the opening 31 a of the detection chamber 31, that is, on the upper part of the detection chamber 31. Since the leaked steam from the inner case 21 is trapped in the upper part of the detection chamber 31, the temperature detected by the temperature sensor 32 is maintained at a peak state for a predetermined time. Therefore, the detection operation of the temperature sensor 32 is stabilized.
[0040]
(4) The heat storage device 11 is provided with a heat transfer tube damage detection device D. Therefore, the breakage of the heat transfer tube 25 can be detected without stopping the operation of the heat storage device 11.
[0041]
(Another example)
The above-described embodiment may be modified and implemented as follows.
In the present embodiment, the detection chamber 31 is arranged on the side opposite to the side from which both ends of the heat transfer tube 25 are led out. However, as shown by the two-dot chain line in FIG. The detection chamber 31 may be provided on one of a pair of side walls orthogonal to the side wall and facing each other. Even in this case, erroneous detection of leaked steam can be suppressed as compared with the case where the detection chamber 31 is provided on the side wall from which both ends of the heat transfer tube 25 are led out in the outer case 23.
[0042]
-In this embodiment, although the detection chamber 31 was formed integrally with the lid 23b, the detection chamber 31 may be a separate member. Even in this case, the same effects as the effects (1) to (4) described in the first embodiment can be obtained.
[0043]
In the present embodiment, the detection chamber 31 has a rectangular tube shape, but is not limited to this shape, and may have a cylindrical shape, an elliptical cylindrical shape, or the like. In this case, the same effects as in the first embodiment can be obtained.
[0044]
In the present embodiment, the vapor outlet pipe 41 is connected (that is, opened) to a substantially central portion of the detection chamber 31, but may be as shown in FIG. 3A or 3B. . That is, as shown in FIG. 3A, a vapor outlet pipe 41 is opened at the upper part of the detection chamber 31, and the detection end 32a of the temperature sensor 32 is disposed below the vapor outlet pipe 41. Further, as shown in FIG. 3 (b), a vapor outlet pipe 41 is opened in the upper part of the detection chamber 31, and the detection end 32a of the temperature sensor 32 is arranged at a substantially horizontal position. In other words, the detection end 32a is arranged so as to face the opening of the steam outlet pipe 41 (the connection part of the steam outlet pipe 41 to the detection chamber 31). In any case, effects similar to the effects (1) to (4) in the first embodiment can be obtained.
[0045]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, breakage of a heat exchanger tube can be discovered at an early stage, without stopping operation.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a heat storage device according to an embodiment.
FIG. 2 is a plan view of the heat storage device according to the embodiment.
FIGS. 3A and 3B are enlarged cross-sectional views of a main part of a heat transfer tube breakage detecting device according to another embodiment.
[Explanation of symbols]
11: heat storage device, 21: inner case constituting a case,
24: heat storage material constituting a heat source; 25: heat transfer tube; 26: electric heater;
31 ... a detection chamber constituting a steam detection unit,
31a ... opening of the detection chamber
32 temperature sensors constituting temperature detecting means and a steam detecting section;
41 ... a steam outlet pipe constituting a communication passage,
51: a control device that constitutes the judgment means and the steam detection unit; D: a heat transfer tube damage detection device.

Claims (5)

A heat transfer tube breakage detecting device that detects breakage of a heat transfer tube that performs heat exchange between the heat medium and the heat source, wherein the heat transfer medium is disposed inside the case and the heat medium flows therein.
A steam detection unit provided outside the case and capable of detecting heat medium steam generated in the case,
A communication path that guides the heat medium vapor generated in the case to the vapor detection unit,
A heat transfer tube breakage detection device, wherein when detecting heat medium steam from the communication passage, the steam detection unit determines that the heat transfer tube is broken. 2. The heat transfer tube damage detection device according to claim 1, wherein, in the case, the steam detection unit is arranged on a side opposite to a lead-out side of both ends of the heat transfer tube. 3. The steam detector,
A detection chamber provided outside the case,
Temperature detection means for detecting the temperature in the detection chamber,
Judgment means for judging the presence or absence of breakage of the heat transfer tube based on the temperature in the detection chamber detected by the temperature detection means,
3. The heat transfer tube damage detection device according to claim 1, wherein the inside of the case and the inside of the detection chamber are communicated with each other through the communication passage. 4. 4. The heat transfer tube breakage detecting device according to claim 3, wherein an upper portion of the detection chamber is closed, and an opening is provided at the lower portion. An electric heater that heats the heat storage material filled in the case, and a heat transfer tube that is disposed in the case and through which a heat medium flows therein and performs heat exchange between the heat medium and the heat storage material. Heat storage device,
A heat storage device comprising the heat transfer tube damage detection device according to any one of claims 1 to 4.

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