Title of the invention: Tube leak detection device and tube leak detection method
Technical field
[0001]
　The present disclosure relates to a tube leak detection device and a tube leak detection method.
Background technology
[0002]
　For example, in a multi-tube heat exchanger, the water can be warmed by exchanging heat between the water circulating in the tube and the gas circulating outside the tube. If the gas flowing outside the tube contains a corrosive component, the tube may corrode and a tube leak may occur.
[0003]
　According to Patent Document 1, in a boiler plant that circulates water supply in a water supply system, water vapor or water leaks are found from the temperature change of the leak detection point measured by the temperature sensor when the amount of make-up water supplied to the water supply system increases. Is described to detect.
Prior art literature
Patent documents
[0004]
Patent Document 1: Japanese Patent No. 5019861
Outline of the invention
Problems to be solved by the invention
[0005]
　However, in the case of a leak due to a small hole in the tube, there is a problem that it is difficult to detect the leak because the temperature change is small.
[0006]
　In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a tube leak detection device and a tube leak detection method capable of detecting even a small leak.
Means for solving the problem
[0007]
　The tube leak detection device according to at least one embodiment of the present invention raises the temperature of the liquid by exchanging heat between the liquid flowing in at least one tube and the fluid flowing outside the at least one tube. A tube leak detection device that detects a leak in at least one tube in the heat exchanger to be used, and includes an inlet side on-off valve and an outlet-side on-off valve provided at the inlet end and the outlet end of at least one tube. A pressure detecting member for detecting the pressure in the tube between the inlet side on-off valve and the outlet-side on-off valve is provided.
[0008]
　According to this configuration, when each of the inlet-side on-off valve and the outlet-side on-off valve is closed, the temperature of the liquid in the tube rises due to heat exchange with the fluid, and a part of the liquid is vaporized. When there is no leak in the tube, the pressure in the tube rises because the pressure of the gas in which a part of the liquid is vaporized rises due to heat exchange with the fluid. However, when there is a leak in the tube, the gas leaks when the pressure of the gas rises, so that the rise in the pressure inside the tube becomes smaller than when there is no leak in the tube. Small leaks can also be detected based on such pressure changes in the tube.
[0009]
　In some embodiments, each of the at least one tube is configured to allow the liquid in the tube or at least one of the vaporized gas in the tube to be ejected between the inlet and outlet valve. May be provided.
[0010]
　If the pressure inside the tube rises too quickly, the pressure inside the tube may damage the tube. However, according to this configuration, if the pressure inside the tube becomes too high, the safety valve can eject at least one of the liquid or gas inside the tube to reduce the pressure, which may damage the tube. Can be reduced.
[0011]
　In some embodiments, a monitor for displaying the value detected by the pressure detecting member over time may be further provided.
[0012]
　According to this configuration, the pressure change in the tube can be visually understood on the monitor, so that the pressure change in the tube can be easily understood and the leak can be easily detected.
[0013]
　In some embodiments, the inlet-side on-off valve and the outlet-side on-off valve may be solenoid valves, respectively.
[0014]
　According to this configuration, the inlet side on-off valve and the outlet side on-off valve can be remotely operated, so that the workability of the opening / closing work of the inlet-side on-off valve and the outlet-side on-off valve can be improved. Further, by combining with the monitor, the tube leak detection device can be operated without on-site work, so that the workability of leak detection can be improved.
[0015]
　The tube leak detection method according to at least one embodiment of the present invention includes a step of circulating a liquid in at least one tube, a step of circulating a fluid having a temperature higher than that of the liquid outside the at least one tube, and a liquid. And after circulating the fluid, it includes a step of sealing the liquid in at least one tube and a step of detecting the pressure in the tube after sealing the liquid in at least one tube.
[0016]
　According to this method, when the liquid in the tube is sealed, the temperature of the liquid in the tube rises due to heat exchange with the fluid, and a part of the liquid is vaporized. When there is no leak in the tube, the pressure in the tube rises because the pressure of the gas in which a part of the liquid is vaporized rises due to heat exchange with the fluid. However, when there is a leak in the tube, the gas leaks when the pressure of the gas rises, so that the rise in the pressure inside the tube becomes smaller than when there is no leak in the tube. Small leaks can also be detected based on such pressure changes in the tube.
[0017]
　In some embodiments, the inlet and outlet ends of at least one tube are each provided with an inlet-side on-off valve and an outlet-side on-off valve, and the step of sealing the liquid in at least one tube is an inlet-side on-off valve. It may include closing both the valve and the outlet side on-off valve.
[0018]
　According to this method, the liquid in the tube can be easily sealed, so that the tube leak detection work can be easily performed.
[0019]
　In some embodiments, the step of setting an upper limit of the pressure in at least one tube and the tube of at least one of the liquid in the tube or the gas vaporized by the liquid when the pressure in the tube reaches the upper limit. It may further include a step of ejecting from.
[0020]
　If the pressure inside the tube rises too quickly, the pressure inside the tube may damage the tube. However, according to this method, when the pressure in the tube becomes too high, at least one of the liquid or the gas in the tube is ejected from the tube to reduce the pressure, thereby reducing the risk of the tube being damaged. can do.
Effect of the invention
[0021]
　According to at least one embodiment of the present disclosure, when each of the inlet-side on-off valve and the outlet-side on-off valve is closed, the temperature of the liquid in the tube rises due to heat exchange with the fluid, and a part of the liquid evaporates. .. When there is no leak in the tube, the pressure in the tube rises because the pressure of the gas in which a part of the liquid is vaporized rises due to heat exchange with the fluid. However, when there is a leak in the tube, the gas leaks when the pressure of the gas rises, so that the rise in the pressure inside the tube becomes smaller than when there is no leak in the tube. Small leaks can also be detected based on such pressure changes in the tube.
A brief description of the drawing
[0022]
FIG. 1 is a schematic view showing a configuration of a heat exchanger provided with a tube leak detection device according to a first embodiment of the present disclosure.
FIG. 2 is a graph schematically showing a pressure change in a tube when a tube leak is detected in the tube leak detection device according to the first embodiment of the present disclosure.
FIG. 3 is a schematic view showing the configuration of a heat exchanger provided with the tube leak detection device according to the second embodiment of the present disclosure.
FIG. 4 is a graph schematically showing a pressure change in a tube when a tube leak is detected in the tube leak detection device according to the second embodiment of the present disclosure. It is a schematic diagram which shows the structure.
Mode for carrying out the invention
[0023]
　Hereinafter, some embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments are not intended to limit the scope of the present invention only to them, but are merely explanatory examples.
[0024]
(Embodiment 1) As
　shown in FIG. 1, the economizer 1 which is a heat exchanger includes a plurality of tubes 2 and a shell 3 including a plurality of tubes 2 inside. Water supply to the boiler circulates inside the tube 2, and combustion gas of the boiler circulates inside the shell 3 (outside the tube 2). The economizer 1 is provided with a tube leak detection device 10 for detecting leaks in each tube 2. Although five tubes 2 are shown in FIG. 1, the configuration is not limited to the configuration including the five tubes 2, and at least one tube 2 may be provided.
[0025]
　The tube leak detection device 10 includes an inlet side on-off valve 11 and an outlet-side on-off valve 12 provided at the inlet end 2a and an outlet end 2b of each tube 2, and an inlet-side on-off valve 11 and an outlet-side on-off valve 12. A pressure sensor 13 which is a pressure detecting member for detecting the pressure in the tube 2 is provided between the two. Although not an essential configuration requirement for the tube leak detection device 10, the tube leak detection device 10 may include a monitor 14 that displays a change over time in a value detected by the pressure sensor 13.
[0026]
　Next, the operation of detecting the leak of the tube 2 by the tube leak detection device 10 will be described.
　In the economizer 1, the water supply to the boiler circulates in each tube 2 and the combustion gas of the boiler circulates in the shell 3, so that the water supply and the combustion gas exchange heat and the water supply is heated. In order to determine whether or not a leak has occurred in each tube 2, both the inlet side on-off valve 11 and the outlet-side on-off valve 12 are closed while the water supply and the combustion gas are exchanging heat. That is, the water supply is sealed in the tube 2 between the inlet side on-off valve 11 and the outlet side on-off valve 12.
[0027]
　The temperature of the water supply sealed in the tube 2 between the inlet-side on-off valve 11 and the outlet-side on-off valve 12 rises due to heat exchange with the combustion gas, and a part of the water supply is eventually vaporized. The pressure rises as the vaporized gas is further heated by the combustion gas. As shown in FIG. 2, when there is no leak in the tube 2, when a part of the water supply is vaporized, the pressure of the vaporized gas increases, so that at a certain point in time (t = t 1 in FIG. 2). The pressure P (value detected by the pressure sensor 13) in the tube 2 rises from (when).
[0028]
　On the other hand, when a leak occurs in the tube 2, a part of the water supply is vaporized and the pressure of the vaporized gas rises. As a result, the vaporized gas leaks and the rise in the pressure P in the tube 2 is suppressed. .. Therefore, when a leak occurs in the tube 2, the pressure P remains constant as shown in FIG. 2, or the pressure P rises as compared with the case where the tube 2 does not leak. Becomes gradual. A small leak can also be detected based on such a change in pressure P in the tube 2.
[0029]
　As for the pressure change in the tube 2, the change of the indicated value of the pressure sensor 13 (the position indicated by the needle in the case of the pressure sensor of analog display or the numerical value in the case of the pressure sensor of digital display) is observed. It can be judged by. However, by using the monitor 14 (see FIG. 1) capable of displaying the change with time of the pressure P as shown in FIG. 2, the change of the pressure P in the tube 2 can be visually understood. In particular, by using the monitor 14, it is possible to visually compare the change in the pressure P in the leak-free tube 2 with the change in the pressure P in the leaky tube 2. Therefore, by using the monitor 14, it becomes easy to understand the change of the pressure P in the tube 2, and it becomes easy to detect the leak.
[0030]
(Embodiment 2)
　Next, the tube leak detection device according to the second embodiment will be described. The tube leak detection device according to the second embodiment is different from the first embodiment in that the tube is prevented from being damaged during the operation of the tube leak detection. In the second embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.
[0031]
　As shown in FIG. 3, a bypass pipe is connected so as to connect between each inlet side on-off valve 11 and each outlet side on-off valve 12 and a pipe 4 connecting the downstream side of each outlet side on-off valve 12 and the boiler. 5 is provided, and a safety valve 20 is provided in each of the bypass pipes 5. The safety valve 20 is configured to be capable of ejecting at least one of water supply and water vapor in the tube 2 when the pressure in the tube 2 reaches an arbitrarily set upper limit value. At least one of the water supply or steam ejected from the tube 2 flows into the pipe 4 via the bypass pipe 5. Other configurations are the same as those in the first embodiment. In the second embodiment as in the first embodiment, the monitor 14 is not an indispensable constituent requirement of the tube leak detection device 10.
[0032]
　The operation of the tube leak detection device 10 according to the second embodiment to detect the leak of the tube 2 is the same as that of the first embodiment. However, in the tube 2 having no leak, the pressure P in the tube 2 rises as in the first embodiment. Therefore, if the rising speed is too fast and the operation of opening the outlet side on-off valve 12 becomes slow, the pressure P in the tube 2 is increased. May be damaged by.
[0033]
　However, in the second embodiment, the upper limit value of the pressure for not damaging the tube 2 is determined in advance, and the safety valve 20 that opens at this upper limit value is provided. Then, as shown in FIG. 4, the increase in pressure P in the tube 2 is too early to can not be opened quickly the outlet side switching valve 12, the pressure P is an upper limit value P h and reaches (FIG. 4 Then, when t = t 2 ), when the safety valve 20 is opened, at least one of the water supply and the water vapor is ejected from the tube 2 and the pressure P in the tube 2 is lowered, so that the tube 2 can be prevented from being damaged.
[0034]
　In each of the first and second embodiments, the heat exchanger has been described as the economizer 1 used in the boiler, but any use as long as it is a heat exchanger in which the liquid flows through the tube 2 and the liquid is heated. It may be a heat exchanger of. Therefore, the fluid flowing outside the tube 2 may be any fluid depending on the application of the heat exchanger.
[0035]
　In each of the first and second embodiments, the monitor 14 is used, and the inlet side on-off valve 11 and the outlet-side on-off valve 12 are made into remote-operable solenoid valves, so that the tube leak detection device 10 can be installed without on-site work. Since it can be operated, the workability of leak detection can be improved. Further, even when the monitor 14 is not provided, if each of the inlet side on-off valve 11 and the outlet-side on-off valve 12 is a solenoid valve, the workability of the opening / closing work thereof can be improved.
[0036]
　When each of the inlet side on-off valve 11 and the outlet side on-off valve 12 is a solenoid valve that can be remotely operated in the configuration of the first embodiment, the outlet-side on-off valve 12 is opened at the upper limit of the pressure in the tube 2. By setting, the same effect as when the safety valve 20 as in the second embodiment is provided can be obtained. Also, implementation if the configuration of Embodiment 2 of the respective inlet-side valve 11 and the outlet-side on-off valve 12 was available for the remote control solenoid valve, the upper limit value P of the pressure P in the tube 2 h second upper limit lower than By setting the outlet-side on-off valve 12 to open, it is possible to prevent the tube 2 from being damaged in two stages of the outlet-side on-off valve 12 and the safety valve 20.
Code description
[0037]
1 Economizer (heat exchanger)
2 Tube
2a (tube) inlet end
2b (tube) outlet end
3 Shell
4 piping
5 Bypass piping
10 Tube leak detector
11 Inlet side on-off valve
12 Outlet side on-off valve
13 Pressure sensor (pressure) Detection member)
14 Monitor
20 Safety valve
The scope of the claims
[Claim 1]
　In a heat exchanger that raises the temperature of the liquid by exchanging heat between the liquid flowing in the at least one tube and the fluid flowing outside the at least one tube, a leak in the at least one tube is caused. A tube leak detection device for detecting,
　the inlet side on-off valve and the outlet-side on-off valve provided at each of the inlet end and the outlet end of the at least one tube, the inlet-side on-off valve and the outlet-side
　on-off valve. A
tube leak detection device including a pressure detecting member for detecting the pressure in the tube between the tubes .
[Claim 2]
　Each of the at least one tube is provided with a safety valve configured so that at least one of the liquid in the tube and the gas vaporized by the liquid can be ejected between the inlet-side on-off valve and the outlet-side on-off valve. The tube leak detection device according to claim 1.
[Claim 3]
　The tube leak detection device according to claim 1 or 2, further comprising a monitor for displaying a value detected by the pressure detecting member over time.
[Claim 4]
　The tube leak detection device according to any one of claims 1 to 3, wherein the inlet side on-off valve and the outlet-side on-off valve are solenoid valves, respectively.
[Claim 5]
　A step of circulating a liquid in
　at least one tube, a step of circulating a fluid having a temperature higher than that of the liquid outside the at least one tube,
　and after circulating the liquid and the fluid, the at least one. A tube leak detection method including
　a step of sealing a liquid
in a tube and a step of detecting a pressure in the tube after sealing the liquid in the at least one tube .
[Claim 6]
　An inlet side on-off valve and an outlet side on-off valve are provided at each of the inlet end and the outlet end of the
　at least one tube, and the step of sealing the liquid in the at least one tube is the inlet side on-off valve and the outlet. The tube leak detection method according to claim 5, wherein both of the side on-off valves are closed.
[Claim 7]
　The tube is a step of setting an upper limit of the pressure in the at least one tube, and at least one of the
　liquid in the tube or a gas vaporized by the liquid when the pressure in the tube reaches the upper limit.
The tube leak detection method according to claim 5 or 6, further comprising a step of ejecting from .