Heat thermo water level measurement system and heat thermo water level measurement method

Abstract

To provide a heat thermo type water level measuring technique capable of achieving continuous water level detection and having high resolution of the water level detection.SOLUTION: The system 10 includes a receiving unit 21 that receives outputs from a plurality of temperature sensors 11n (n = 1 to 5) arranged at intervals in a water depth direction (Z-axis direction), an energizing unit 25 that energizes heaters 15 arranged around the temperature sensors 11n (n = 1 to 5) and configured to emit heat energy, a calculating unit 22 that averages outputs 12 of the temperature sensors 11n (n = 1 to 5) to calculate a mean 13, a computing unit 23 that computes a magnitude relationship between the outputs 12 of the temperature sensors 11n and the mean 13, and a water level determining unit 26 that determines a water level 17 based on a computation result corresponding to each of the temperature sensors 11n (n = 1 to 5).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a heat-thermal water level measurement technology having a temperature sensor and a heater. [Background technology]

[0002] Heat-thermal water level gauges are used as water level gauges installed in the fuel pools of nuclear power plants. These heat-thermal water level gauges have a temperature sensor and a heater, and utilize the principle that heat transfer is different between air and water. They distinguish between air and water from the difference in temperature change detected by the temperature sensor when the heater is turned on and off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-20851 Summary of the Invention [Problem to be solved by the invention]

[0004] Heat thermo water level gauges install multiple temperature sensors in a line along the depth direction and detect the water level by heating the area around these temperature sensors with a heater. Therefore, the installation interval of the temperature sensors determines the resolution of water level detection. However, if the temperature sensors are installed too close together, the heater's heat will reach other measurement points, affecting the ability to distinguish between air and water. For this reason, there is a limit to how narrow the installation interval of the temperature sensors can be. Furthermore, if the installation interval of the temperature sensors is increased, the effect of heating can be avoided, but this inevitably leads to a decrease in resolution and a decrease in the accuracy of water level detection.

[0005] On the other hand, water level gauges installed in fuel pools are required to have the ability to continuously detect water levels, but such a function has been difficult to achieve in principle. The reason is that when the heater ON / OFF cycle is shortened during water level detection, the water or air around the temperature sensor cannot keep up with the temperature recovery (cooling) to its original temperature. If this condition continues, the reference temperature of the water or air just before the heater is turned ON increases, while the final temperature when the heater is turned OFF does not increase significantly. This reduces the amount of change in temperature detected by the temperature sensor when the heater is turned ON / OFF, leading to the problem of the sensor misidentifying air as water.

[0006] Furthermore, if the heater ON / OFF time interval is increased, the water level determination interval also becomes longer, which causes the monitoring to be unable to keep up with sudden fluctuations in the water level.Furthermore, if water droplets that have aggregated near the temperature sensor located in the air move due to gravity and come into contact with the temperature sensor, there is an issue where the air is mistakenly determined to be underwater.

[0007] The embodiments of the present invention have been made in consideration of the above circumstances, and have an object to provide a heat thermo type water level measurement technology that realizes continuous water level detection and has high resolution for water level detection. [Means for solving the problem]

[0008] In the embodiment, the heat thermo type water level measurement system includes a receiving unit that receives output values ​​from a plurality of temperature sensors arranged at intervals in the water depth direction, an electrical current supply unit that energizes heaters arranged around the temperature sensors and emits thermal energy, a calculation unit that averages the output values ​​of each of the temperature sensors to calculate an average value, a calculation unit that calculates the magnitude relationship between the output value of each of the temperature sensors associated with the emission of the thermal energy and the average value, and a water level determination unit that determines the water level based on the results of the calculation corresponding to each of the temperature sensors. [Effects of the Invention]

[0009] Embodiments of the present invention provide a heat-thermo water level measurement technique that achieves continuous water level detection and provides high resolution water level detection. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram of a heat thermo type water level measurement system showing a first embodiment of the present invention. [Figure 2] FIG. 4 is a block diagram of a heat thermo type water level measurement system showing a second embodiment of the present invention. [Figure 3] FIG. 10 is a block diagram of a heat thermo type water level measurement system showing a third embodiment of the present invention. [Figure 4] 1 is an XY horizontal cross-sectional view of a water level meter applied to the first and second embodiments. [Figure 5] FIG. 11 is an XY horizontal cross-sectional view of a water level meter applied to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a block diagram of a heat thermo type water level measurement system 10A (10) showing a first embodiment of the present invention. Fig. 4 is an XY horizontal cross-sectional view of a water level gauge 14A (14) applied to the first embodiment.

[0012] As described above, the heat thermo type water level measurement system 10A (10) is composed of a control unit 20A (20) and a water level indicator 14A (14). Of these, the control unit 20A (20) controls a plurality of temperature sensors 11 arranged at intervals in the water depth direction (Z-axis direction). n (n=1~5) output value 12 n and a receiver 21 for receiving these temperature sensors 11. n (n=1 to 5) and a power supply unit 25 for supplying power to the heater 15 that emits thermal energy, and each temperature sensor 11 n (n=1~5) output value 12 n a calculation unit 22 that calculates an average value 13 by averaging the values ​​of the temperature sensor 11 that are generated by the thermal energy release;n a calculation unit 23 for calculating the magnitude relationship between each output value 12 and the average value 13 of each temperature sensor 11; n and a water level determination unit 26 that determines the water level 17 based on the calculation results of the calculation unit 23 corresponding to (n=1 to 5).

[0013] As shown in Fig. 1, the heater 15 is configured from a pair of wires with high electrical resistance along the water depth direction (Z-axis direction) from the temperature sensor 111 at the bottom to the temperature sensor 115 at the top, as shown in cross section in Fig. 4. The pair of wires is sealed in a sealed tube filled with magnesium oxide, which has high thermal conductivity. When electricity is applied to the heater 15, thermal energy generated by Joule heat is released to the outside via the liquid phase 31 and the gas phase 32.

[0014] In the figure, the heater 15 is connected to a plurality of temperature sensors 11 n In this example, two pairs of wires are arranged over the entire depth direction of the heater 15 (n=1 to 5). However, the heater 15 to be applied is not limited to this, and multiple temperature sensors 11 n A pair of wires can be arranged corresponding to each of (n=1 to 5).

[0015] Multiple temperature sensors 11 n (n=1 to 5) is the output value 12 after the heater 15 is energized because the thermal diffusivity of the thermal energy differs depending on whether the surroundings are a gas phase 32 or a liquid phase 31. n In other words, there is a difference in the temperature sensor 11 n When the heater 15 is exposed to the gas phase 32, the thermal energy supplied from the heater 15 does not diffuse into the gas phase 32, which has a small thermal diffusivity, and therefore the output value 12 n On the other hand, the temperature sensor 11 n When the heater 15 is immersed in the liquid phase 31, the heat energy supplied from the heater 15 is diffused into the liquid phase 31, which has a large thermal diffusivity, and the output value 12 n does not rise much.

[0016] Temperature Sensor 11 n(n=1 to 5) are thermocouple wires housed in a sheath tube with a closed tip. This sheath tube is filled with magnesium oxide as an insulating material along with the wires. In a thermocouple, wires of different metals are welded at the tip, and the ambient temperature of this tip is measured based on the thermoelectromotive force detected at the opposite end.

[0017] As shown in FIG. 4, the temperature sensor 11 n The temperature sensors 11 (n=1 to 5) are arranged concentrically around the heater 15 in the XY horizontal cross section. n The arrangement of (n=1 to 5) is not particularly limited.

[0018] Returning to FIG. 1, the explanation will continue. Based on an operator's command, the power supply unit 25 passes a current through the heater 15 to generate Joule heat and release a certain amount of thermal energy into the surrounding area. The magnitude and duration of the current passed through the heater 15 can be set in advance. In the first embodiment, the water level 17 is repeatedly determined while the current is continuously passed through the heater 15. Therefore, the water level 17 can be determined continuously over time while the power supply unit 25 is operating.

[0019] The receiver 21 receives the temperature signals from the plurality of temperature sensors 11. n (n=1~5) output value 12 n The receiving unit 21 receives the output value 12 in real time, regardless of the operation of the power supply unit 25. n is being received.

[0020] Temperature Sensor 11 n (n=1 to 5) outputs a voltage in the mV range of 12 n The Joule heat generated by passing a current through the heater 15 has different thermal diffusivities depending on whether the surroundings are a gas phase 32 or a liquid phase 31. Therefore, the voltage output (output value 12 n ) makes a difference.

[0021] The receiving unit 21 receives the temperature sensor 11 nThe weak voltage output from the analog circuit can be processed to an output value of 12 n and outputs the converted value 12 from the calculation unit 22 to the calculation unit 23. n Input the average value 13 (n=1 to 5) and output the value 12 n (n=1 to 5) is used to determine the magnitude relationship with each of the output values ​​12 n In all of the cases (n=1 to 5), the heater 15 is in an ON state and heat energy is being emitted.

[0022] Average value 13 and output value 12 n Based on the judgment of the magnitude relationship between the temperature sensors 11 n (n=1 to 5) can be identified as existing in either the liquid phase 31 or the gas phase 32. Specifically, if the output value 12 is smaller than the average value 13, it is in the liquid phase 31, and if it is larger than the average value 13, it is in the gas phase 32. n The water level determination unit 26 then determines that the two temperature sensors 11 are positioned such that the liquid phase 31 and the gas phase 32 are interchanged. n It is determined that there is a water level of 17 between them.

[0023] Specifically, the temperature sensor 11 shown in FIG. n (n=1~5) output value 12 n Suppose that the values ​​(n=1 to 5) are, in order, "50," "50," "50," "100," and "100." When the calculation unit 22 averages each output value 12, the average value 13 obtained is "70."

[0024] Next, the calculation unit 23 calculates the magnitude relationship between the output value 12 and the average value 13, and obtains the calculation results "output value < average value," "output value < average value," "output value < average value," "output value > average value," and "output value > average value" in that order. Then, based on this calculation result, the water level determination unit 26 determines the temperature sensor 11 where the magnitude relationship between the "output value" and the "average value" is reversed. n It is determined that there is a water level of 17 between (n=3,4).

[0025] According to the heat-thermo type water level measurement system 10 of this embodiment, the heater 15 is continuously energized, and the temperature sensor 11 adjacent to the heater 15 is n The mutual influence between the temperature sensors 11 is also reduced. n This allows the placement intervals of the sensors to be reduced, and also makes it possible to increase the resolution of water level detection.

[0026] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a block diagram of a heat thermo type water level measurement system 10B (10) showing the second embodiment of the present invention. In Fig. 2, parts having the same configuration or function as Fig. 1 are indicated by the same reference numerals, and duplicated explanations will be omitted.

[0027] In the heat thermo type water level measurement system 10B (10) of the second embodiment, the switching unit 27 can switch between water level determination by continuous current application as described in the first embodiment and water level determination by intermittent current application, thereby implementing two methods. Here, the intermittent current application method is the same as the method of turning the heater on and off as described in the "Background Art." Compared to the continuous current application method, the intermittent current application method has the disadvantage that the determination results are obtained discretely, but it has the advantage of excellent determination accuracy and low energy consumption depending on the situation.

[0028] When the switching unit 27 is set to "intermittent energization", the energizing unit 25 energizes the heater 15 by turning it on and off. Then, the calculation unit 22 calculates the temperature of the temperature sensor 11 after the heater 15 has released thermal energy. n (n=1~5) output value 12 n (n=1~5) Change 18 n (The average value 13 (FIG. 1) is not calculated.) Then, the calculation unit 23 calculates the amount of change 18 n and the threshold value 19 (output value 12 n The magnitude relationship between the average value 13 and the average value 13 is not calculated).

[0029] The water level determination unit 26 determines the calculated change amount 18 nand the threshold value 19, the corresponding temperature sensor 11 n Specifically, if the amount of change in the output value 12 is smaller than the threshold 19, it is in the liquid phase 31, and if it is larger than the threshold 19, it is in the gas phase 32. n The water level determination unit 26 then determines that the two temperature sensors 11 are located at positions where the identification results of the liquid phase 31 and the gas phase 32 are switched. n It is determined that there is a water level of 17 between them.

[0030] (Third embodiment) Next, a third embodiment of the present invention will be described with reference to Fig. 3. Fig. 3 is a block diagram of a heat thermo type water level measurement system 10C (10) showing the third embodiment of the present invention. The heat thermo type water level measurement system 10C of the third embodiment differs from the first and second embodiments described above in that the water level indicator 14B has a cylindrical body 16 and the control unit 20C (20) has an air supply unit 35. In Fig. 3, parts having the same configuration or function as Figs. 1 and 2 are indicated by the same reference numerals, and duplicated explanations will be omitted. Furthermore, Fig. 3 is based on Fig. 1, but it can also be based on Fig. 2.

[0031] The cylindrical body 16 is configured so that when immersed in the liquid phase 31 contained in the container 30, the outside and inside thereof maintain the same water level 17. That is, the cylindrical body 16 has openings at the bottom and top ends in the depth direction, and is configured so that even if the water level 17 of the liquid phase 31 in the container 30 changes, the water level 17 inside follows. Furthermore, holes 37 are provided on the side circumferential surface of the cylindrical body 16.

[0032] The air supply unit 35 supplies purging air 33 from the opening at the top of the cylindrical body 16 through holes 37 on the side circumferential surface of the cylindrical body 16. This prevents water vapor evaporated from the liquid phase 31 from remaining in the gas phase 32 inside the cylindrical body 16, preventing moisture in the gas phase 32 from condensing and forming dew near the temperature sensor 11. This reduces the occurrence of errors in erroneously determining the gas phase 32 as the liquid phase 31.

[0033] Furthermore, the control unit 20C (20) is provided with a temperature adjustment unit 38 that adjusts the temperature of the purged air 33. This can further enhance the effect of preventing condensation near the temperature sensor 11. Furthermore, the temperature adjustment unit 38 can switch between multiple temperatures of the air 33 and set them. This can further enhance the accuracy of identifying the gas phase 32.

[0034] The material of the partition wall of the cylindrical body 16 that separates the liquid phase 31 into an inside and an outside may be metal, glass, resin, etc., but is not particularly limited, and a material with a small heat transfer coefficient is preferable. The horizontal cross section of the cylindrical body 16 is also exemplified as being cylindrical, but is not limited to this and can be any shape, such as rectangular or elliptical.

[0035] According to at least one embodiment of the heat thermo type water level measurement system described above, the water level is determined based on the magnitude relationship between the output values ​​of each temperature sensor and the average value of these output values, thereby realizing continuous water level detection and providing a technology with high resolution for this water level detection.

[0036] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as the inventions described in the claims and their equivalents. [Explanation of symbols]

[0037] 10 (10A, 10B, 10C)...Heat thermo type water level measurement system, 11...Temperature sensor, 12...Temperature sensor output value, 13...Average value, 14 (14A, 14B)...Water level gauge, 15...Heater, 16 (16A, 16B, 16C)...Cylindrical body, 17...Water level, 18...Amount of change, 19...Threshold value, 20...Control unit, 21...Receiving unit, 22...Calculation unit, 23...Comparing unit, 25...Electrification unit, 26...Water level determination unit, 27...Switching unit, 30...Condition, 31...Liquid phase, 32...Gas phase, 33...Air, 35...Air supply unit, 36...Temperature adjustment, 37...Hole, 38...Temperature adjustment unit.

Claims

1. a receiving unit that receives output values ​​from a plurality of temperature sensors that are spaced apart in the water depth direction; an electric current supply unit that supplies electric current to a heater that is disposed around the temperature sensor and that emits thermal energy; a calculation unit that calculates an average value by averaging the output values ​​of each of the temperature sensors; a calculation unit that calculates a magnitude relationship between the output value of each of the temperature sensors associated with the release of the thermal energy and the average value; a water level determination unit that determines the water level based on the results of the calculations corresponding to each of the temperature sensors.

2. The heat-thermo type water level measurement system according to claim 1, A heat thermo type water level measurement system in which the heater is continuously energized during the period in which the water level is repeatedly determined.

3. The heat-thermo type water level measurement system according to claim 2, a switching unit that switches the current supply unit from continuous current supply to intermittent current supply, When the intermittent energization is set, the calculation unit calculates, instead of the average value, an amount of change in the output value of the temperature sensor after the thermal energy is released; The calculation unit calculates the magnitude relationship between the amount of change and a threshold value instead of the magnitude relationship between the output value and the average value.

4. The heat-thermo type water level measurement system according to claim 1 or 2, a cylindrical body in which the temperature sensor and the heater are arranged and whose inside maintains the same water level as the outside; a heat thermostatic water level measurement system including an air supply unit that supplies purging air from the opening at the top of the cylindrical body through the hole in the side surface of the cylindrical body.

5. The heat-thermo type water level measurement system according to claim 4, A heat thermostatic water level measurement system including a temperature adjustment unit that adjusts the temperature of the air to be purged.

6. receiving output values ​​from a plurality of depth-spaced temperature sensors; energizing a heater disposed around the temperature sensor and emitting thermal energy; averaging the output values ​​of each of the temperature sensors to calculate an average value; calculating a magnitude relationship between the output value of each of the temperature sensors associated with the release of the thermal energy and the average value; and determining the water level based on the results of the calculation corresponding to each of the temperature sensors.

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