JP6752169B2 - Thermocouple liquid level measurement system - Google Patents

Description

The present invention relates to a thermocouple type liquid level measurement system, and more particularly to a thermocouple type liquid level measurement system suitable for measuring the liquid level of a liquid stored in a container using a sensor including a thermocouple and a heater. ..

As a liquid level gauge for measuring the liquid level of the liquid in the container, a thermocouple with a heater is used as a sensor. A thermocouple with a heater is a combination of a heater made of nickel-chromium alloy or the like and a thermocouple, and whether the sensor is below or above the liquid surface due to the temperature rise of the thermocouple when a current is applied to the heater. It can be detected if it exists.

When used as a liquid level gauge, multiple sensors are placed at different heights to detect whether each sensor is above or below the liquid level, and the sensor above the liquid level and the sensor below the liquid level. It is determined that the liquid level exists between the sensors in. That is, it is a liquid level gauge that measures the water level discretely, and although it is inferior to a liquid level gauge that can measure the water level continuously such as a float type or pressure type liquid level gauge, the fineness of the measured value is inferior, but the sensor. Since it can be composed of metal or other inorganic substances, it has the advantage that it can be used even in a high temperature or high radiation environment.

Further, in the liquid level gauge using the thermocouple with a heater described above, it takes time from applying the current to determining the difference in temperature rise. In particular, in the method of sequentially switching one power source and applying a current to a plurality of heaters, the liquid level can be measured only when all the heaters are energized. Therefore, it takes a long time to measure the liquid level, and it is necessary to devise to quickly measure the liquid level that fluctuates in a short time.

Patent Document 1 describes a water level temperature measuring device in which a temperature sensor measures a temperature in pool water or air in order to measure a liquid level in a structure in a short time regardless of the level of the liquid. Power is supplied to the heater of the temperature sensor to generate heat, and the heater ON / OFF circuit that puts this temperature sensor in the measurement state and the order in which the multiple temperature sensors of the water level temperature measuring device are put in the measurement state are determined and set. Used based on the heater control device that controls the power supply to the heater by the heater ON / OFF circuit based on this order, the temperature information from the water level temperature measuring instrument, and the power supply information to the heater from the heater ON / OFF circuit. A liquid level measurement system configured with a determination unit for determining the pool water level of the fuel storage pool and a determination unit is described.

Japanese Unexamined Patent Publication No. 2016-20851

As described above, in a liquid level gauge using a thermocouple with a heater, it is necessary to energize the heater so that the difference between the temperature rise below the liquid level and the temperature rise above the liquid level of the sensor unit becomes clear. There is. Therefore, the liquid level gauge using the thermocouple with a heater has a problem that the power consumption during operation is larger than that in the case of using a passive sensor. In particular, when it can be operated only by a battery, or when a battery is used together in preparation for a situation where power is not supplied from the outside for high reliability, a large power consumption becomes a problem.

For example, a nuclear power plant has a mechanism to supply power necessary for stabilizing the power plant in an emergency by using a battery in case both external power transmission and an emergency generator become unusable. .. In a nuclear power plant, various pumps, valves, control devices, etc. need to be operated, so a large capacity battery is installed. At this time, it is effective to install a liquid level gauge using a thermocouple with a heater for important equipment in the nuclear power plant in consideration of the harsh temperature and radiation environment in an emergency, but it is passive. It consumes more power than a sensor and may need to increase battery capacity in order to extend its operating time.

Further, in order to prolong the operation time without changing the battery capacity, it is possible to extend the operation duration by lengthening the measurement cycle, but the monitoring property is deteriorated.

However, the above-mentioned Patent Document 1 does not describe any countermeasures for the above-mentioned problems.

The present invention has been made in view of the above points, and an object of the present invention is that even if a liquid level gauge using a thermocouple with a heater is used, the liquid level can be measured in a harsh environment and is reliable. It is an object of the present invention to provide a thermocouple type liquid level measuring system capable of maintaining the property or extending the operation duration by the battery without deteriorating the monitorability.

In the thermocouple type liquid level measurement system of the present invention, in order to achieve the above object, a plurality of thermocouples and a thermocouple with a heater in which heaters arranged in the vicinity of the thermocouple are housed in the same sheath are used as a sensor unit. A thermocouple type liquid level measuring system that measures the liquid level in a container using a battery, a first liquid level measuring device that measures the liquid level from the thermocouple signal of the thermocouple, and the thermocouple. A second liquid level measuring device that measures the liquid level from a thermocouple signal and a heater control signal of the heater, and the first liquid according to the remaining power of the battery or the temperature of the environment in which the container is installed. It is provided with a position measuring device or a measurement control device that selectively operates one of the second liquid level measuring devices, and is adjacent to the selected first liquid level measuring device or the second liquid level measuring device. It is characterized in that the liquid level in the container is measured based on the temperature difference of the sensor unit or the amount of temperature rise from the start of energization of the sensor unit to the completion of energization.

According to the present invention, even if a liquid level gauge using a thermocouple with a heater is used, it is possible to measure the liquid level in a harsh environment and maintain reliability, or monitorability. It is possible to obtain a thermocouple type liquid level measurement system capable of extending the operation duration of the battery without lowering it.

It is an overall block diagram which shows Example 1 of the thermocouple type liquid level measurement system of this invention. It is a vertical cross-sectional view which shows the sensor part of the thermocouple with a heater adopted in Example 1 of the thermocouple type liquid level measurement system of this invention. It is sectional drawing which follows the AA line of FIG. 2A. It is a block diagram which shows the measurement control apparatus adopted in Example 1 of the thermocouple type liquid level measurement system of this invention. It is a block diagram which shows the 1st liquid level measuring apparatus adopted in Example 1 of the thermocouple type liquid level measuring system of this invention. It is a block diagram which shows the 2nd liquid level measuring apparatus adopted in Example 1 of the thermocouple type liquid level measuring system of this invention. It is a flowchart which shows the operation in Example 1 of the thermocouple type liquid level measurement system of this invention. It is a figure which shows the liquid level determination example by the 1st liquid level measuring apparatus adopted in Example 1 of the thermocouple type liquid level measuring system of this invention. It is a figure which shows the determination example under the liquid level by the gas-liquid determination apparatus adopted in Example 1 of the thermocouple type liquid level measurement system of this invention. It is a figure which shows the judgment example on the liquid level by the gas-liquid judgment apparatus adopted in Example 1 of the thermocouple type liquid level measurement system of this invention. It is a figure which shows an example of the energization timing by the 2nd liquid level measuring apparatus adopted in Example 1 of the thermocouple type liquid level measuring system of this invention. It is an overall block diagram which shows Example 2 of the thermocouple type liquid level measurement system of this invention. It is a figure which shows an example of the correspondence table of the temperature measured by the thermocouple in Example 2 of the thermocouple type liquid level measurement system of this invention, and the current value of the current setter which should be set at that time. It is an overall block diagram which shows Example 3 of the thermocouple type liquid level measurement system of this invention. It is a block diagram which shows the 1st liquid level measuring apparatus adopted in Example 3 of the thermocouple type liquid level measuring system of this invention. It is a flowchart which shows the operation in Example 3 of the thermocouple type liquid level measurement system of this invention, and is an example when the measurement by the 1st liquid level measurement apparatus is selected. It is a flowchart which shows the operation in Example 3 of the thermocouple type liquid level measurement system of this invention, and is an example when the measurement by the 2nd liquid level measurement apparatus is selected. It is an overall block diagram which shows Example 4 of the thermocouple type liquid level measurement system of this invention.

Hereinafter, the thermocouple type liquid level measurement system of the present invention will be described based on the illustrated examples. In each embodiment, the same reference numerals are used for the same components.

FIG. 1 shows Example 1 of the thermocouple type liquid level measurement system of the present invention.

As shown in the figure, the thermocouple type liquid level measuring system of this embodiment has four thermocouples with heaters 4a and 4b supported by a support material 3 in order to measure the liquid level 2 in the container 1. 4c and 4d (the number of thermocouples with heaters is not limited to four, but a plurality of thermocouples may be used) are arranged in the height direction. Sensor units 5a, 5b, 5c, and 5d are provided at one end of each of the thermocouples 4a, 4b, 4c, and 4d with a heater, and the other ends are via the first connectors 6a, 6b, 6c, and 6d. Cables 7a, 7b, 7c, 7d are attached. The cables 7a, 7b, 7c, 7d are connected to the liquid level meter 100 via the second connectors 8a, 8b, 8c, 8d.

The liquid level meter 100 is from a thermocouple temperature converter 9, a heater switching device 10, a heater power supply 11, a first liquid level measuring device 12, a second liquid level measuring device 13, a measuring timer 14, and a measuring control device 15. It is configured.

Inside the liquid level meter 100, thermocouple signals from the thermocouples 4a, 4b, 4c, and 4d with heaters are output to the thermocouple temperature converter 9 and the heater switching device 10, respectively. Further, the heater switching device 10 is connected to the heater power supply 11 via a heater wire. The thermocouple temperature converter 9 is connected to the first liquid level measuring device 12 and the second liquid level measuring device 13, and the signal of the thermocouple temperature converter 9 is sent to the first liquid level measuring device 12 and the second liquid level measuring device 12. Is output to the liquid level measuring device 13. The heater power supply 11 connected to the heater switch 10 is connected to the second liquid level measuring device 13. A measurement timer 14 that emits a timing signal at each preset cycle is connected to the second liquid level measuring device 13. Further, the first liquid level measuring device 12 and the second liquid level measuring device 13 are connected to the measurement control device 15, and the display device 16 is connected to the measurement control device 15. Further, power is supplied to the liquid level meter 100 from the battery 17 and the external power source 18.

2 (a) and 2 (b) show the details of the sensor unit 5a of the thermocouple 4a with a heater, which is one of the four described above.

As shown in FIGS. 2 (a) and 2 (b), in the sensor unit 5a, the thermocouple 22, the heater 23, and the heater lead 24 are electrically separated and stored in the sheath 21 by an insulating material 25 such as an inorganic substance. ing.

FIG. 3 shows a configuration example of the measurement control device 15 adopted in this embodiment.

As shown in the figure, the measurement control device 15 is provided with an operation panel 31 for an operator to perform various operations and selections, and the operation panel 31 has a start button 32, a stop button 33, and a first operation panel 31. The selection button 34 of the liquid level measuring device 12 and the selection button 35 of the second liquid level measuring device 13 are arranged.

These start button 32, stop button 33, selection button 34 of the first liquid level measuring device 12, and selection button 35 of the second liquid level measuring device 13 are connected to the controller 36. The controller 36 is provided with a memory 37 for storing the measured liquid level, and the current liquid level is first set by the communication devices 38 and 39 together with various operation / selection signals based on the operation panel 31. It is possible to transmit to the liquid level measuring device 12 and the second liquid level measuring device 13.

FIG. 4 shows a configuration example of the first liquid level measuring device 12 adopted in this embodiment.

As shown in the figure, the first liquid level measuring device 12 adopted in this embodiment calculates the temperature difference between the adjacent sensor units from the thermocouple signals of the plurality of sensor units 5a, 5b, 5c, and 5d. A temperature difference detection unit 46 and a liquid level determination unit 47 that determines that there is a liquid level between two adjacent sensor units when the temperature difference detected by the temperature difference detection unit 46 exceeds a predetermined value. It has.

Then, temperature signals 45a, 45b, 45c, 45d are input to the first liquid level measuring device 12 from the thermocouple temperature converter 9, and the respective temperature signals 45a, 45b, 45c, 45d are temperature difference detection units. It is input to the subtractors 41a, 41b, 41c constituting 46, and the output of the subtractors 41a, 41b, 41c is input to the comparators 42a, 42b, 42c. As another input to the comparators 42a, 42b, 42c, a setting device 44 for giving a reference value for determination is connected, and the comparators 42a, 42b, 42c and the setting device 44 constitute a liquid level determination unit 47. To do. The outputs of the comparators 42a, 42b, and 42c are input to the arithmetic unit 43, and the liquid level signal 60 is output from the arithmetic unit 43.

FIG. 5 shows a configuration example of the second liquid level measuring device 13 adopted in this embodiment.

As shown in the figure, temperature signals 51a, 51b, 51c, 51d are input to the second liquid level measuring device 13 from the thermocouple temperature converter 9, and the respective temperature signals 51a, 51b, 51c, 51d are , Input to the latch circuits 53a, 53b, 53c, 53d connected to the energization start pulses 52a, 52b, 52c, 52d and the latch circuits 55a, 55b, 55c, 55d connected to the energization completion pulses 54a, 54b, 54c, 54d. Then, the signal output via the subtractors 56a, 56b, 56c, 56d is compared with the reference value from the setter 57 in the comparators 58a, 58b, 58c, 58d. The outputs of the comparators 58a, 58b, 58c, and 58d are the qi of the initialization device 101 and the first sensor unit that select the sensor unit closest to the water level measured last time as the first sensor unit when the timing signal is received. From the judgment result by the liquid judgment device 102, the order determination unit 103 that determines the propriety and order of energization to other sensor units, and the judgment result for a plurality of sensor parts 5a, 5b, 5c, 5d by the gas-liquid judgment device 102, the liquid level After the liquid level is determined, the liquid level signal 60, the sensor selection signal 110, which are taken into the arithmetic unit 59 provided with the liquid level determination unit 104 and stop the energization of the remaining sensor units, are obtained as the calculation result. The heater communication signal 111 is output.

The latch circuits 53a, 53b, 53c, 53d, 55a, 55b, 55c, 55d, the subtractors 56a, 56b, 56c, 56d, the comparators 58a, 58b, 58c, 58d, and the setter 57 are used to connect the gas-liquid determination device 102. In this gas-liquid determination device 102, the sensor units 5a, 5b, 5c, and 5d are below or above the liquid surface based on the signal from the thermocouple 22 and the control signal from the heater 23. Is determined.

Next, the operation of the thermocouple type liquid level measurement system of the present embodiment described above will be described with reference to the flowchart of FIG.

The thermocouple type liquid level measuring system of this embodiment starts the measurement when the operator presses the start button 32 of the operation panel 31 shown in FIG. 3 (S1). At this time, if the selection button 34 of the first liquid level measuring device 12 is pressed, the measurement by the first liquid level measuring device 12 is performed, and the selection button 35 of the second liquid level measuring device 13 is pressed. For example, measurement by the second liquid level measuring device 13 is selected (S2).

When the measurement by the first liquid level measuring device 12 is selected, the first liquid level measuring device 12 is provided with the sensor units 5a, 5b, 5c, and 5d of the thermocouples 4a, 4b, 4c, and 4d with heaters. The signal from the thermocouple 22 is converted into temperature signals 45a, 45b, 45c, 45d by the thermocouple temperature converter 9 and captured (S3). The captured temperature signals 45a, 45b, 45c, 45d are input to the subtractors 41a, 41b, 41c, and the temperature difference between the adjacent sensor units 5a, 5b, 5c, and 5d (between the two sensor units). Is output. The temperature difference output from the subtractors 41a, 41b, 41c is input to the comparators 42a, 42b, 42c and compared with the reference temperature difference (for example, 5 ° C.) set by the setter 44, and the temperature difference is obtained. 1 is output when is larger than the reference temperature difference, and 0 is output when is smaller than the reference temperature difference.

These output results are input to the arithmetic unit 43, and the height between the adjacent sensor units having a temperature difference exceeding the reference temperature difference (between the two sensor units) is determined as the liquid level (S4), and this value. Is stored in the memory 37 (S5), and the liquid level signal 60 is output. The display device 16 updates the liquid level display based on the output liquid level signal 60 (S6).

FIG. 7 shows an example of determining the liquid level by the first liquid level measuring device 12.

In the example shown in the figure, of the temperature signals 45a, 45b, 45c, and 45d output from the four sensor units 5a, 5b, 5c, and 5d, the temperature difference between the temperature signals 45b and 45c serves as a reference value5. It can be seen that the temperature exceeds ° C. and the height between the sensor unit 5b and the sensor unit 5c is determined as the liquid level. During the period in which the first liquid level measuring device 12 is selected, the above process is repeated at regular intervals until the stop button 33 is pressed.

On the other hand, when the measurement by the second liquid level measuring device 13 is selected, the second liquid level measuring device 13 first waits for the timing signal from the measurement timer 14 (S9). After receiving the timing signal, the initialization device 101 of the arithmetic unit 59 selects the sensor directly under the liquid level last time, but since there is no previous value in the first measurement, the lowest sensor unit 5d is selected as the initial value.

Then, the heater switching device 10 is connected to the thermocouple with heater 4d by the sensor selection signal 110 (see FIG. 5) from the second liquid level measuring device 13, and the heater power supply 11 is connected by the heater energization signal 111 (see FIG. 5). Turn on for a predetermined time.

As a result, a preset current is applied to the heater 23 of the sensor unit 5d, the sensor unit 5d is heated, and the temperature of the thermocouple 22 rises. When a predetermined time elapses, the heater power supply 11 is turned off by the heater energization signal 111, and heating is stopped. The gas-liquid determination device 102 of the second liquid level measuring device 13 uses the energization start pulse 52d and the energization start pulse 52d generated at the start of energization of the temperature signal 51d in which the signal from the thermocouple 22 is converted by the thermocouple temperature converter 9. It is taken in by the latch circuits 53d and 55d at the timing synchronized with the energization completion pulse 54d generated at the time of completion. The temperature at the start of energization and the temperature at the completion of energization are input to the subtractor 56d, and the amount of temperature rise is output as the difference between the two. This temperature rise amount is input to the comparator 58d and compared with the determination threshold value of the temperature rise amount preset by the setting device 57.

Then, when the amount of temperature rise is larger than the determination threshold value, it is determined that the air is in the air and 1 is output. When the amount of temperature rise is equal to or less than the determination threshold value, it is determined that the temperature is below the liquid level and 0 is output (S10).

8 (a) and 8 (b) show a determination example of the gas-liquid determination device 102.

In the examples shown in FIGS. 8A and 8B, when the sensor unit is below the liquid level (FIG. 8A), the temperature rise is about 9 ° C. and is set to about 40 ° C. Do not exceed the judgment threshold. On the other hand, when the sensor unit is on the liquid surface (in the air) (FIG. 8 (b)), the temperature rise becomes about 89 ° C., which exceeds the determination threshold value set at about 40 ° C. By appropriately setting the determination threshold value in this way, it is possible to determine whether the sensor unit is below the liquid surface or in the air.

When the determination result of the sensor unit 5d is below the liquid level (S11), the order determination unit 103 of the arithmetic unit 59 sets the energization order of the sensor unit from directly above the first selected sensor unit 5d to above. That is, the sensor unit 5c, the sensor unit 5b, and the sensor unit 5a are selected in this order.

Then, the selected sensor units are sequentially energized and the gas-liquid determination is performed by the same procedure as when the gas-liquid determination of the sensor unit 5d is performed (S12). When the selected sensor unit is determined to be on the liquid level, that is, in the air, the subsequent energization of the sensor unit is stopped, and the process proceeds to the liquid level determination (S13). The liquid level determination unit 104 determines that the liquid level is at an intermediate height between the sensor unit determined to be below the liquid level and the sensor unit determined to be in the air (S14), and stores the liquid level in the memory 37. (S15) Outputs the liquid level signal 60. The display device 16 updates the liquid level display based on the output liquid level signal 60 (S16).

On the other hand, when the sensor unit 5d is in the air, the energization order of the sensor unit is set from directly below to the bottom, but since the sensor unit 5d is the lowest sensor unit, the order determination unit 103 has no selection sensor unit. , Proceed to the liquid level determination (S18). In this case, the liquid level determination unit 104 determines that there is no liquid level (S14).

FIG. 9 shows an example of energization timing when the second liquid level measuring device 13 is selected.

In the example shown in the figure, the sensor unit 5d is first selected and the heater 23 is energized. At this time, since the liquid level 2 is between the sensor unit 5b and the sensor unit 5c, the sensor unit 5d is determined to be below the liquid level. Therefore, the sensor unit 5c directly above is selected as the next sensor unit. Since the sensor unit 5c is determined to be below the liquid level, the sensor unit 5b above the sensor unit 5b is selected. Since the sensor unit 5b is on the liquid level, the sensor unit 5b is determined to be in the air, the energization to the sensor unit 5a after this is stopped, and the liquid level 2 is between the sensor unit 5b and the sensor unit 5c. It is judged.

The second measurement is started by receiving a timing signal generated after a predetermined cycle has elapsed by the measurement timer 14. In the second measurement, the initialization device 101 selects the sensor unit 5c directly below the liquid level last time. Since the liquid level 2 has not changed in the second measurement, it is determined that the sensor unit 5c is below the liquid level.

Then, the order determination unit 103 selects the next sensor unit in the order of the sensor unit 5b and the sensor unit 5a from directly above to the top. Since the sensor unit 5b is determined to be in the air, the subsequent energization of the sensor unit 5a is stopped and the process proceeds to the liquid level determination, and the liquid level 2 is determined to be between the sensor unit 5b and the sensor unit 5c.

In the third measurement, the liquid level 2 is lowered between the sensor unit 5c and the sensor unit 5d. First, the sensor unit 5c is selected by the initialization device 101 and determined to be in the air. In response to this, the order determination unit 103 selects the sensor unit downward from the sensor unit 5d directly below. However, in this case, since there is no sensor unit below the sensor unit 5d, only the sensor unit 5d is selected.

Since the sensor unit 5d is determined to be below the liquid level, the process proceeds to the liquid level determination at this stage, and the liquid level 2 is determined to be between the sensor unit 5c and the sensor unit 5d. In the fourth measurement, the sensor unit 5a, which is directly below the liquid level last time, is first selected by the initialization device 101.

In the process of measuring the liquid level, for example, when the temperature of the environment in which the container 1 is installed rises and the difference from the temperature in the liquid becomes small, the operator operates the first liquid level measuring device 12. By determining that the measurement based only on the temperature used is not functioning sufficiently and pressing the selection button 35 of the second liquid level measuring device 13, the heating by the heater 23 of the second liquid level measuring device 13 is used. Then, it is possible to switch to the measurement for determining the liquid level and maintain the reliability of the measurement.

Further, for example, when the remaining electric power of the battery 17 is low and it becomes difficult for the second liquid level measuring device 13 to continue the liquid level measurement by heating by the heater 23, the selection button of the first liquid level measuring device 12 By pressing 34, it is possible to switch to the measurement based only on the temperature using the first liquid level measuring device 12. As a result, the measurement can be continued even when the remaining power of the battery 17 is low.

As described above, by using this embodiment, it is possible for the operator to appropriately switch the measurement method, the capacity of the battery 17 can be reduced without deteriorating the monitoring property, and the battery cost can be reduced and the weight can be reduced. And miniaturization can be achieved. In addition, even if the remaining amount of stored power of the battery 17 becomes low, the operation can be continued under certain environmental conditions.

Therefore, by adopting the configuration of this embodiment, even if a liquid level gauge using a thermocouple with a heater is used, the liquid level can be measured in a harsh environment without deteriorating the monitorability. It is possible to extend the operation duration by the battery.

FIG. 10 shows Example 2 of the thermocouple type liquid level measurement system of the present invention.

The thermocouple type liquid level measurement system of this embodiment is different from the case of the first embodiment of FIG. 1 in that a current setting device 19 is added to the liquid level meter 100.

That is, when the measurement by the second liquid level measuring device 13 is selected for the second liquid level measuring device 13 constituting the liquid level measuring panel 100, the signal and the heater from the thermocouple 22 are sent to the measurement control device 15. It is provided with a current setter 19 that sets a current value and / or an energization time based on a control signal from 23.

The current setting device 19 of the present embodiment sets the current energizing the heater 23 to an optimum value required for gas-liquid determination when the second liquid level measuring device 13 is selected.

FIG. 11 shows an example of a correspondence table between the temperature measured by the thermocouple 22 and the current value of the current setter 19 to be set at that time.

In the current setting device 19 added in this embodiment, the temperature signals 51a, 51b, 51c, 51d converted by the thermocouple temperature converter 9 are input via the second liquid level measuring device 13 and input. The temperature is applied to the table of FIG. 11, the current set value is determined by insertion, and is transmitted to the second liquid level measuring device 13. The second liquid level measuring device 13 transmits the transmitted current value to the heater power supply 11 together with the heater energization signal 111 to control the current value.

As a result, not only the same effect as that of the first embodiment can be obtained, but also the electric power required for energizing the heater can be minimized, and the usage period of the bally 17 can be extended.

FIG. 12 shows Example 3 of the thermocouple type liquid level measurement system of the present invention.

In the thermocouple type liquid level measurement system of this embodiment, an automatic switching device 20 is added to the measurement control device 15 and the remaining amount of electric power is detected in the battery 17 as compared with the case of the first embodiment of FIG. The difference is that the power remaining amount sensor 61 is added.

Further, FIG. 13 shows a configuration example of the first liquid level measuring device 12 adopted in the thermocouple type liquid level measuring system of this embodiment.

The first liquid level measuring device 12 adopted in the thermocouple type liquid level measuring system of this embodiment is the first liquid level adopted in the thermocouple type liquid level measuring system of Example 1 shown in FIG. Compared with the measuring device 12, the difference is that a propriety determination device 48 for determining whether or not the liquid level can be determined and outputting a result signal is added to the arithmetic unit 43.

Then, when the result signal of the pass / fail determination device 48 is received and the liquid level determination is impossible, the automatic switching device 20 automatically switches to the liquid level measurement by the second liquid level measuring device 13. When the remaining power of the battery 17 by the power remaining amount sensor 61 of the battery 17 becomes equal to or less than the predetermined remaining power, the automatic switching device 20 measures the first liquid level from the measurement by the second liquid level measuring device 13. The measurement is switched to the measurement by the measuring device 12.

As shown in the flowchart of FIG. 14, when the measurement by the first liquid level measuring device 12 adopted in this embodiment is selected, the temperature difference by the subtractors 42a, 42b and 42c is setter 44. If the reference value of is not reached, the pass / fail determination device 48 transmits a determination failure signal 63 to the measurement control device 15. Upon receiving the undeterminable signal 63, the measurement control device 15 automatically switches the selection of the measurement control device 15 to the second liquid level measurement device 13 (SS1) by the automatic switching device 20 between S4 and S5. It is added to.

As a result, even when the operator cannot constantly monitor and switch the selection, if the monitoring by the first liquid level measuring device 12 is insufficient, the heating by the heater 23 of the second liquid level measuring device 13 is used. It is possible to switch to the liquid level judgment and continue highly reliable measurement.

Further, as shown in the flowchart of FIG. 15, when the measurement by the second liquid level measuring device 13 is selected, the power remaining amount signal from the power remaining amount sensor 61 of the battery 17 becomes smaller than the predetermined value. In this case, the automatic switching device 20 adds a process (SS2) for automatically switching the selection of the measurement control device 15 to the first liquid level measuring device 12 between S2 and S9.

As a result, the same effect as that of the first embodiment can be obtained, and even when the operator cannot constantly monitor and switch the selection, the measurement can be continued when the remaining power of the battery 17 becomes low. it can.

FIG. 16 shows Example 4 of the thermocouple type liquid level measurement system of the present invention.

The thermocouple type liquid level measuring system of this embodiment is different from the case of the first embodiment of FIG. 1 in that a temperature predictor 62 is added to the first liquid level measuring device 12.

In the thermocouple type liquid level measuring system of this embodiment, when the second liquid level measuring device 13 is selected, the heater 23 is energized, so that the temperatures of the sensor units 5a, 5b, 5c, and 5d Is higher than the original temperature in the liquid. In this state, when the operator presses the selection button 34 of the first liquid level measuring device 12, correct measurement is possible after a sufficient time has passed since the energization of the heater 23 was completed, but immediately after the switching, The liquid level judgment may not function properly due to the influence of the heater energization.

The temperature predictor 62 in the present embodiment applies the temperature change to an exponential function or the like when the selection signal changes immediately after switching from the second liquid level measuring device 13 to the first liquid level measuring device 12. Extrapolate and replace the values of the temperature signals 45a, 45b, 45c, 45d input to the first liquid level measuring device 12 with the extrapolated values.

As a result, not only the same effect as that of the first embodiment can be obtained, but also the correct liquid level determination can be performed immediately after switching from the second liquid level measuring device 13 to the first liquid level measuring device 12.

It should be noted that the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1 ... Container, 2 ... Liquid level, 3 ... Support material, 4a, 4b, 4c, 4d ... Thermocouple with heater, 5a, 5b, 5c, 5d ... Sensor unit, 6a, 6b, 6c, 6d ... First connector , 7a, 7b, 7c, 7d ... Cable, 8a, 8b, 8c, 8d ... Second connector, 9 ... Thermocouple temperature converter, 10 ... Heater switching device, 11 ... Heater power supply, 12 ... First liquid level Measuring device, 13 ... second liquid level measuring device, 14 ... measuring timer, 15 ... measuring control device, 16 ... display device, 17 ... battery, 18 ... external power supply, 19 ... current setting device, 20 ... automatic switching device, 21 ... sheath, 22 ... thermocouple, 23 ... heater, 24 ... heater lead, 25 ... insulating material, 31 ... operation panel, 32 ... start button, 33 ... stop button, 34 ... selection button of the first liquid level measuring device , 35 ... Second liquid level measuring device selection button, 36 ... Controller, 37 ... Memory, 38, 39 ... Communication device, 41a, 41b, 41c, 56a, 56b, 56c, 56d ... Subtractor, 42a, 42b , 42c, 58a, 58b, 58c, 58d ... Comparer, 43, 59 ... Arithmetic, 44, 57 ... Setting device, 45a, 45b, 45c, 45d, 51a, 51b, 51c, 51d ... Temperature signal, 46 ... Temperature Difference detection unit, 47, 104 ... Liquid level determination unit, 48 ... Possibility determination device, 52a, 52b, 52c, 52d ... Energization start pulse, 53a, 53b, 53c, 53d, 55a, 55b, 55c, 55d ... Latch circuit, 54a, 54b, 54c, 54d ... Energization completion pulse, 60 ... Liquid level signal, 61 ... Battery power level sensor, 62 ... Temperature predictor, 63 ... Undecidable signal, 100 ... Liquid level meter, 101 ... Initialization Device, 102 ... Gas / liquid determination device, 103 ... Order determination unit, 110 ... Sensor selection signal, 111 ... Heater energization signal.

Claims (18)

A thermocouple type liquid level measurement system that measures the liquid level in a container by using a plurality of thermocouples and a thermocouple with a heater in which heaters arranged in the vicinity of the thermocouple are housed in the same sheath as a sensor unit. ,
The battery, the first liquid level measuring device for measuring the liquid level from the thermocouple signal of the thermocouple, and the second liquid level for measuring the liquid level from the thermocouple signal of the thermocouple and the heater control signal of the heater. Measurement that selects and operates either the first liquid level measuring device or the second liquid level measuring device according to the remaining power of the measuring device and the temperature of the environment in which the container is installed. Equipped with a control device
Based on the temperature difference between the adjacent sensor units by the selected first liquid level measuring device or the second liquid level measuring device, or the amount of temperature rise from the start of energization to the completion of energization of the sensor unit. A thermocouple type liquid level measuring system characterized by measuring the liquid level in the container. In the thermocouple type liquid level measuring system according to claim 1,
The plurality of the thermocouples with heaters are arranged in the height direction in the container, and the sensor unit is provided at one end of each of the plurality of thermocouples with heaters, and the first end is provided with the sensor unit. A thermocouple type liquid level measuring system characterized in that a cable is attached via a connector, and the cable is connected to a liquid level meter via a second connector. In the thermocouple type liquid level measuring system according to claim 2.
The liquid level meter is composed of a thermocouple temperature converter, a heater switching device, a heater power supply, a first liquid level measuring device, a second liquid level measuring device, a measuring timer and a measuring control device.
Inside the liquid level meter, thermocouple signals from the plurality of thermocouples with heaters are output to the thermocouple temperature converter and the heater switching device, respectively, and the heater switching device is connected to the heater power supply. The thermocouple temperature converter is connected to the first liquid level measuring device and the second liquid level measuring device, and the temperature signal of the thermocouple temperature converter is transmitted to the first liquid level measuring device and the first liquid level measuring device. It is output to the liquid level measuring device of 2 and at the same time
The heater power supply connected to the heater switching device is connected to the second liquid level measuring device, the measuring timer is connected to the second liquid level measuring device, and the first liquid is connected. A thermocouple type liquid level measuring system, wherein the position measuring device and the second liquid level measuring device are connected to the measurement control device, and a display device is connected to the measurement control device. In the thermocouple type liquid level measuring system according to claim 3,
A thermocouple type liquid level measuring system characterized in that a battery and an external power source are connected to the liquid level measuring panel to supply electric power. In the thermocouple type liquid level measuring system according to any one of claims 1 to 4.
The sensor unit is a thermocouple type liquid level measuring system in which the thermocouple, the heater, and the heater lead are electrically separated and stored in the sheath by an insulating material. In the thermocouple type liquid level measuring system according to claim 1,
When the measurement by the second liquid level measuring device is selected, the second liquid level measuring device is provided with a measurement timer that emits a timing signal at each preset cycle, and the second liquid level measuring device is provided with the second liquid level measuring device. , The initialization device that selects the sensor unit closest to the water level measured last time as the first sensor unit together with the reception of the timing signal, and the sensor unit is below the liquid level from the thermocouple signal and the heater control signal. A gas-liquid determination device that determines whether or not the sensor unit is on the liquid surface, and an order determination unit that determines the pros and cons and order of energization to other sensor units based on the determination result of the gas-liquid determination device of the first sensor unit. It is characterized in that it is provided with a liquid level determination unit that determines the liquid level from the determination results for a plurality of sensor units by the gas-liquid determination device and stops energization of the remaining sensor units after the liquid level determination. Thermocouple type liquid level measurement system. In the thermocouple type liquid level measuring system according to claim 3 or 4.
A plurality of temperature signals are input to the second liquid level measuring device from the thermoelectric pair temperature converter, and each of the temperature signals is sent to a first latch circuit connected to an energization start pulse and an energization completion pulse. The signal input to the connected second latch circuit and output from the first and second latch circuits via the subtractor is input to the comparator and is a reference from the setter connected to the comparator. Compared with the value, the output from the comparer is from the initialization device that selects the sensor unit closest to the water level measured last time as the first sensor unit, and the judgment result that the first sensor unit is selected. The liquid level is determined from the order determination unit that determines the propriety and order of energization of other sensor units, and the judgment results for the plurality of sensor units, and after the liquid level is determined, the energization of the remaining sensor units is stopped. A thermoelectric pair type liquid level measurement system characterized in that a liquid level signal, a sensor selection signal, and a heater communication signal, which are taken into an arithmetic unit including a determination unit and obtained as a calculation result by the arithmetic unit, are output. In the thermocouple type liquid level measuring system according to claim 7.
With the first and second latch circuits, the subtractor, the comparator, and the setter, whether the sensor unit is below or above the liquid surface is determined from the thermocouple signal and the heater control signal. A thermocouple type liquid level measurement system characterized in that it constitutes a gas-liquid judgment device for judgment. In the thermocouple type liquid level measuring system according to claim 8.
The gas-liquid determination device synchronizes the temperature signal obtained by converting the signal from the thermocouple with the thermocouple temperature converter with the energization start pulse generated at the start of energization and the energization completion pulse generated at the completion of energization. The temperature at the start of energization and the temperature at the end of energization, which are taken in by the first and second latch circuits at the timing, are input to the subtractor, and the temperature rise amount is output as the difference between the two, and this temperature. The amount of increase is input to the comparator and compared with the determination threshold of the amount of temperature increase preset by the setter, and if the amount of temperature increase is larger than the determination threshold, it is determined to be in the air. Then, 1 is output, and when the temperature rise amount is equal to or less than the determination threshold value, it is determined that the temperature is below the liquid level and 0 is output. In the thermocouple type liquid level measuring system according to any one of claims 7 to 9.
The second liquid level measuring device energizes the measurement control device with a current value and / or energization based on the thermocouple signal and the heater control signal when the measurement by the second liquid level measuring device is selected. A thermocouple type liquid level measurement system characterized by having a current setter that sets the time. In the thermocouple type liquid level measuring system according to claim 1,
In the first liquid level measuring device, a temperature difference detecting unit that calculates a temperature difference between adjacent sensor units from thermocouple signals of a plurality of the sensor units and a temperature difference detected by the temperature difference detecting unit are predetermined values. A thermocouple type liquid level measuring system, characterized in that it includes a liquid level determining unit that determines that there is a liquid level between two adjacent sensor units when the above occurs. In the thermocouple type liquid level measuring system according to claim 3 or 4.
A plurality of temperature signals are input to the first liquid level measuring device from the thermocouple temperature converter, and each of the temperature signals is a temperature difference between the thermocouple signals of the plurality of sensor units and adjacent sensor units. Is input to the subtractor constituting the temperature difference detection unit for calculating the above, the output of the subtractor is input to the comparator, and a setting device for giving a reference value for determination is connected to the comparator. When the temperature difference detected by the temperature difference detection unit exceeds the reference value given by the setting device, a liquid level determination unit for determining that there is a liquid level between the two adjacent sensor units is configured. Moreover, the thermocouple type liquid level measuring system is characterized in that the output of the comparer is input to the arithmetic unit and the liquid level signal is output from the arithmetic unit. In the thermocouple type liquid level measuring system according to claim 12,
1 is output when the temperature difference detected by the temperature difference detector is larger than the reference temperature difference given by the setter, and 0 is output when the temperature difference is smaller than the reference temperature difference, and these output results are output to the arithmetic unit. The intermediate height of the adjacent sensor unit that is input and has a temperature difference exceeding the reference temperature difference is determined as the liquid level, and this value is stored in the memory provided in the measurement control device and the liquid level signal. A thermocouple type liquid level measurement system, characterized in that a display device connected to the measurement control device updates the liquid level display based on the output liquid level signal. In the thermocouple type liquid level measuring system according to any one of claims 1 to 13.
The measurement control device includes an automatic switching device that automatically switches to liquid level measurement by the second liquid level measuring device, and the battery is a power remaining amount sensor that detects the remaining amount of electric power of the battery. A thermocouple type liquid level measurement system characterized by being equipped with. In the thermocouple type liquid level measuring system according to claim 14,
The arithmetic unit constituting the first liquid level measuring device is provided with a propriety determination device for determining whether or not the liquid level can be determined and outputting a result signal, and receives the result signal in the feasibility determination device to determine the liquid level. A thermocouple type liquid level measuring system characterized in that the automatic switching device automatically switches to the liquid level measurement by the second liquid level measuring device when the above is not possible. In the thermocouple type liquid level measuring system according to claim 14,
When the remaining power of the battery by the remaining power sensor of the battery becomes equal to or less than the predetermined remaining power, the first liquid level is measured from the measurement by the second liquid level measuring device by the automatic switching device. A thermocouple type liquid level measurement system characterized by switching to device-based measurement. In the thermocouple type liquid level measuring system according to any one of claims 1 to 5.
When the selection signal changes by switching from the second liquid level measuring device to the first liquid level measuring device, the change of the selection signal is applied to the exponential function and externally attached to the first liquid level measuring device. A thermocouple type liquid level measuring system characterized by having a temperature predictor that replaces an input temperature signal value with an extrapolated value. In the thermocouple type liquid level measuring system according to any one of claims 1 to 17.
The measurement control device includes an operation panel for an operator to perform various operations and selections, and the operation panel includes a start button, a stop button, a selection button of the first liquid level measurement device, and the second. A selection button for the liquid level measuring device is arranged, and the start button, the stop button, the selection button for the first liquid level measuring device, and the selection button for the second liquid level measuring device are connected to the controller. The controller is provided with a memory for storing the measured liquid level, and the current liquid level is set by a communication device together with various operation / selection signals based on the operation panel. A thermoelectric pair type liquid level measuring system characterized by transmitting to a position measuring device and the second liquid level measuring device.

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