JP2020153851A - Instantaneous flow rate measuring device for mechanical turbine flowmeter and mechanical turbine flowmeter provided with the same - Google Patents

Abstract

To provide an instantaneous flow rate measuring device for a mechanical turbine flowmeter capable of appropriately measuring and outputting the instantaneous flow rate even if the instantaneous flow rate cannot be normally measured, and also to provide the mechanical turbine flowmeter provided with the same.SOLUTION: An analog display part H1 includes a rotary display part Hm which can display a flow rate of a plurality of digits and whose scale of the minimum digit of the plurality of digits is rotated relative to a fixed pointer Hk. An instantaneous flow rate measuring device for a mechanical turbine flowmeter includes: a pointer value reading part C which continuously reads a relative positional relationship with time between the fixed pointer Hk and the scale in the rotary display part Hm; and an instantaneous flow rate derivation part S1 which derives the instantaneous flow rate of a turbine rotor 14 based on the relative positional relationship read in the pointer value reading part C.SELECTED DRAWING: Figure 1

Description

The present invention is an integrated value of a turbine rotor rotatably provided in a main flow path through which a fluid passes and which rotates with the passage of the fluid, and a fluid flow rate mechanically processed according to the rotation speed of the turbine rotor. The present invention relates to an instantaneous flow measuring device for a mechanical turbine fluid meter having an analog display unit for displaying the above, and a mechanical turbine fluid meter including the instantaneous flow measuring device.

Conventionally, as a gas flow meter for measuring the flow rate of a fluid such as city gas, a turbine flow meter that measures the flow rate of the fluid by rotating a turbine rotor arranged in the flow path of the fluid has been known. (See Patent Document 1). The turbine rotor is composed of a plurality of blades arranged at a predetermined angle with respect to the flow direction of the fluid, and measures the flow rate of the fluid from the rotation speed of the turbine rotor when the fluid passes through the turbine rotor. is there.

Japanese Unexamined Patent Publication No. 4-158222

As the above-mentioned turbine flowmeter, an electronic type (for example, an electronic turbine flowmeter) is known, and a microcomputer board is mounted inside the turbine flowmeter so that an instantaneous flow rate can be acquired. It uses an instantaneous flow rate and is used for surveys related to weighing. On the other hand, a mechanical type (for example, a mechanical turbine flowmeter) does not have a microcomputer board, so that it is not possible to acquire an instantaneous flow rate.
Therefore, in order to conduct a survey on weighing with a mechanical turbine flowmeter, there is no choice but to install different flowmeters in series and compare them, and there is room for improvement.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to determine in advance the magnitude of an abnormality by making it possible to analyze the instantaneous flow rate even if the instantaneous flow rate cannot be measured normally. The point is to provide an instantaneous flow rate measuring device for a mechanical turbine flow meter that can be screened and improve economic efficiency, and a mechanical turbine flow meter equipped with the device.

The instantaneous flow rate measuring device of the mechanical turbine flow meter for achieving the above purpose is
An analog that is rotatably provided in the main flow path through which the fluid passes and displays the integrated value of the turbine rotor that rotates as the fluid passes and the fluid flow rate that is mechanically processed according to the rotation speed of the turbine rotor. It is an instantaneous flow rate measuring device of a mechanical turbine flow meter having a display unit, and its characteristic configuration is
The analog display unit has a rotation display unit capable of displaying a flow rate of a plurality of digits and whose scale rotates relative to a fixed pointer at the minimum digit of the plurality of digits.
The turbine rotor is based on a pointer value reading unit that continuously reads the relative positional relationship between the fixed pointer and the scale on the rotation display unit over time, and the relative positional relationship read by the pointer value reading unit. The point is that it is provided with an instantaneous flow rate derivation unit for deriving the instantaneous flow rate of.

According to the above feature configuration, for example, even in a mechanical turbine flow meter having an analog display unit as a display unit for displaying the flow rate of the fluid, a pointer value reading unit is provided for the rotation display unit which is the smallest digit of the analog display unit. By reading the relative positional relationship between the fixed pointer and the scale continuously over time, the instantaneous flow rate derivation unit derives the instantaneous flow rate of the turbine rotor based on the relative positional relationship, so the pointer value is dynamic to the minimum digit. The instantaneous flow rate can be known by reading the instantaneous flow rate that is indirectly expressed as a change.
By using the instantaneous flow rate measuring device of the above mechanical turbine flow meter, it is possible to judge and screen the magnitude of the abnormality in advance by making it possible to analyze the instantaneous flow rate, and further, another flow meter is installed in series as before. It is not necessary to do so, and the cost of another flow meter, piping members, construction cost, etc. can be reduced to improve economic efficiency.

Further features of the instantaneous flow measuring device of the mechanical turbine flow meter
The pointer value reading unit includes an image acquisition function unit that continuously acquires a display unit image that is an image of the rotation display unit over time, and a scale that is close to the fixed pointer in the scale from the acquired display unit image. The relative positional relationship between the specific scale extraction function unit that extracts the specific scale existing in the above and the amount of change in the distance between the specific scale and the fixed pointer extracted by the specific scale extraction function unit per unit time. It has a change amount reading function unit that reads as
The instantaneous flow rate derivation unit is at a point of deriving the instantaneous flow rate based on the amount of change in the distance between the specific scale and the fixed pointer read by the change amount reading function unit per unit time. ..

In the rotation display unit where the scale rotates relative to the fixed pointer, the amount of change in the distance between the fixed pointer and the specific scale, which is the scale in the vicinity, per unit time is proportional to the instantaneous flow rate of the fluid flow rate. Therefore, the change amount reading function unit reads the change amount, and the instantaneous flow rate derivation unit can derive the instantaneous flow rate with relatively high accuracy based on the read change amount.

As an instantaneous flow rate measuring device for a mechanical turbine flow meter,
The specific scale extraction function unit extracts a scale approaching the fixed pointer as the specific scale, and when the distance between the fixed pointer and the specific scale becomes less than a predetermined first distance, The new specific scale can be extracted.

Further, the specific scale extraction function unit extracts a scale separated from the fixed pointer as the specific scale, and when the distance between the fixed pointer and the specific scale exceeds a predetermined second distance. , The new specific scale can be extracted.

As described above, the specific scale extraction function unit switches the specific scale based on the relative positional relationship between the fixed pointer and the specific scale, so that the amount of change in the distance between the fixed pointer and the scale is appropriate with the flow rate of the fluid. Since the scale when there is a proportional relationship is sequentially selected as a specific scale, the instantaneous flow rate derived based on the scale can be derived more accurately.

Further features of the instantaneous flow measuring device of the mechanical turbine flow meter
A monitor unit for displaying the display unit image acquired by the image acquisition function unit is provided.
The monitor unit can display an arc-shaped arc-shaped marker at a substantially central portion of the display unit image acquired by the image acquisition function unit.
In a state where the image acquisition function unit is positioned with respect to the rotation display unit so that the arc-shaped marker is superimposed on the plurality of scales displayed on the rotation display unit, the image acquisition function unit displays the display unit image. There is a point to acquire.

As described above, when the instantaneous flow rate is derived based on the relative positional relationship between the fixed pointer and the specific scale, it is necessary to appropriately position the image acquisition function unit that acquires the display unit image with respect to the rotation display unit.
According to the above feature configuration, the display unit is in a state where the image acquisition function unit is positioned with respect to the rotation display unit so that the arcuate marker displayed on the monitor unit is superimposed on the plurality of scales displayed on the rotation display unit. Since the image is acquired, the display unit image can be acquired in a state where the positional relationship between the image acquisition function unit and the rotation display unit is adjusted to a certain relationship, so that the display unit image can be acquired without causing a reading error or the like. The instantaneous flow rate can be derived by reading the relative positional relationship.

Further features of the instantaneous flow measuring device of the mechanical turbine flow meter
A bypass flow path connecting the upstream side portion and the downstream side portion of the turbine rotor in the flow direction of the fluid in the main flow path,
A bypass flow rate measuring unit that measures the bypass flow rate of the fluid flowing in the normal flow direction from the upstream side portion to the downstream side portion in the bypass flow path,
A point provided with a measurement performance evaluation unit for evaluating the measurement performance of the instantaneous flow rate derivation unit by comparing the instantaneous flow rate derived by the instantaneous flow rate derivation unit with the bypass flow rate measured by the bypass flow rate measurement unit. It is in.

By having a measurement performance evaluation unit as in the above-mentioned feature configuration, the measurement performance is evaluated as an appropriate flow rate except when over-weighing occurs, for example, when a steep flow rate change occurs. Can be evaluated.

Further features of the instantaneous flow measuring device of the mechanical turbine flow meter
The point is that an instantaneous flow rate integrated value deriving unit for deriving an integrated value of the instantaneous flow rate evaluated as appropriate by the measuring performance evaluation unit is provided.

According to the above characteristic configuration, the integrated flow rate value can be derived as a value more realistic.

The scope of rights of the present application also includes a mechanical turbine flowmeter equipped with the instantaneous flow rate measuring device described above.

The figure regarding the mechanical turbine flow meter provided with the instantaneous flow rate measuring apparatus of this invention External perspective view of mechanical turbine flowmeter External perspective view of a mechanical turbine flowmeter equipped with an instantaneous flow measuring device Graph when the flow rate was continuously varied between 0 nm 3 / ^h and 100 Nm 3 / ^h, measured at with the instantaneous flow rate measurement apparatus mechanical turbine flow meter Graph when the flow rate was continuously varied between 0 nm ³ / h and 100 Nm ³ / h, was measured by an electronic turbine flow meter Graph diagram when the flow rate continuously fluctuated between 100 Nm ³ / h and 150 Nm ³ / h is measured by a mechanical turbine flow meter equipped with an instantaneous flow rate measuring device. Graph diagram when the flow rate continuously changed at 100 Nm ³ / h and 150 Nm ³ / h is measured by an electronic turbine flow meter.

The instantaneous flow rate measuring device 100 of the turbine flow meter according to the embodiment of the present invention and the mechanical turbine flow meter 200 provided with the instantaneous flow rate measuring device 100 make it possible to analyze the instantaneous flow rate even if the instantaneous flow rate cannot be normally measured. By doing so, the magnitude of the abnormality can be judged and screened in advance, and the economic efficiency can be improved.
Hereinafter, the instantaneous flow rate measuring device 100 of the turbine flow meter and the mechanical turbine flow meter 200 provided with the device 100 will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, the mechanical turbine flowmeter 200 includes a turbine rotor 14 rotatably provided in a main flow path 17 through which a fluid (for example, city gas 13A) flows, and a turbine rotor 14 that rotates with the passage of the fluid. It has a pickup device 16 that detects the rotation speed of the turbine rotor 14, and an analog display unit H1 that displays an integrated value of a fluid flow rate derived by mechanically processing the detection result of the pickup device 16. Further, in the bypass flow path 20 that connects the upstream side portion and the downstream side portion of the turbine rotor 14 in the flow direction of the fluid in the main flow path 17 (the direction indicated by the arrow X in FIG. 1), and the bypass flow path 20. A mass flow meter 21 (an example of a bypass flow rate measuring unit) is provided to measure the bypass flow rate of the fluid flowing in the normal flow direction (direction along the arrow Y in FIG. 1) from the upstream side portion to the downstream side portion. ing.
The integrated value of the fluid flow rate displayed on the analog display unit H1 is the integrated value of the flow rate from the start of use of the mechanical turbine flow meter 200 to the present, but instead of this, for example, in the last month or the like. As described above, it can be used as the integrated flow rate value in a predetermined period.

As shown in FIG. 1, the mechanical turbine flowmeter 200 has a flowmeter main body 11 having a main flow path 17 internally connected to a gas pipe (not shown) through which a fluid such as city gas 13A flows. .. Supports 12a and 12b that support the fixed shaft 13 of the turbine rotor 14 while allowing fluid to flow are provided inside the main flow path 17 of the flow meter main body 11, and the turbine rotor is provided with respect to the fixed shaft 13. 14 is rotatably provided.
The turbine rotor 14 having the fixed shaft 13 as the rotation axis is provided symmetrically in the axial direction with a plurality of blades 19 extending radially from the fixed shaft 13. A pickup device 16 is provided at a position where a plurality of blades 19 are provided in the flow direction of the fluid, and the pickup device 16 rotates the turbine rotor 14 each time the blades 19 approach each other due to the rotation of the turbine rotor 14. Outputs pulse signals according to the number. The pulse signal output by the pickup device 16 is mechanically processed and displayed on the analog display unit H1. That is, the flow rate integrated value displayed on the analog display unit H1 is a value proportional to the rotation of the turbine rotor 14, and is an uncorrected value in which over-weighing is not corrected.

Adding a description of the analog display unit H1, the first display unit H1a, which is configured to display a plurality of digits (5 digits in FIG. 1) as the integrated flow value (m ³ ) and displays the decimal point or more, It is composed of a rotation display unit H1b in which the scale displayed on the circular scale plate Hm relative to the fixed pointer Hk is rotated relative to the first decimal place of the minimum digit.

The flow path diameter of the bypass flow path 20 is configured to be smaller than the flow path diameter of the main flow path 17. As an example, the diameter of the bypass flow path 20 can be about 1% or more and 10% or less of the flow path diameter of the main flow path 17. By setting the flow path diameter of the bypass flow path 20 in this way, the flow rate of the fluid flowing through the bypass flow path 20 is made to have a substantially proportional relationship with the flow rate of the fluid flowing through the main flow path 17. Can be in a state. Further, the flow rate of the fluid flowing through the bypass flow path 20 can be made relatively small, and an instrument having a high response speed to the change in the flow rate can be provided as the bypass flow rate measuring unit.
In the embodiment, a mass flow meter 21 is provided as a bypass flow rate measuring unit, and the mass flow meter 21 is provided with thermocouples 21b and 21c at both ends in the direction of fluid flow to the bypass flow path 20. A heat ray heater 21a is provided between them, and the mass flow rate of the fluid flowing through the bypass flow path 20 is measured by measuring the temperature difference between the thermocouples 21b and 21c while the heat ray heater 21a is operating. .. The signal corresponding to the flow rate measured by the mass flow meter 21 is transmitted to the measurement performance evaluation unit S2 of the control device S, which will be described later.

By the way, as described above, since the analog display unit H1 displays the integrated value as well as the uncorrected flow rate, it is difficult to know the instantaneous flow rate from the guideline value, and further, it is excessive. It is also not possible to know the correction value that takes into account the measurement.
Therefore, in the following, even with such a mechanical turbine flowmeter, a device capable of appropriately outputting an instantaneous flow rate and also being able to output a correction value in consideration of over-weighing will be described.

The instantaneous flow rate measuring device 100 of the mechanical turbine flow meter 200 according to the embodiment includes a pointer value reading unit C that continuously reads the relative positional relationship between the fixed pointer Hk and the scale on the rotation display unit H1b over time. It is provided with an instantaneous flow rate deriving unit S1 as a control device S for deriving an instantaneous flow rate of a fluid passing through the turbine rotor 14 based on the relative positional relationship read by the pointer value reading unit C.
To add an explanation, as shown in FIG. 1, the pointer value reading unit C has an image acquisition function unit as a camera C1 that continuously acquires a display unit image which is an image of the rotation display unit H1b over time, and an acquisition function unit. The specific scale extraction function unit C2 that extracts the specific scale Km existing in the vicinity of the fixed pointer Hk among the scales from the displayed display unit image, and the specific scale Km and the fixed pointer Hk extracted by the specific scale extraction function unit C2. It has a change amount reading function unit C3 that reads the amount of change of the distance L per unit time as a positional relationship, and the instantaneous flow rate derivation unit S1 has a specific scale Km read by the change amount reading function unit C3. The instantaneous flow rate is derived based on the amount of change in the distance L from the fixed pointer Hk per unit time.
When the explanation is added by the specific scale extraction function unit C2, as shown in the monitor unit H2 described later shown in FIG. 1, the nearest scale approaching the fixed pointer Hk is extracted as the specific scale Km. When the distance between the fixed pointer Hk and the specific scale Km is less than a predetermined first distance (for example, zero), control is performed to extract a new specific scale Km. As a result, the specific scale Km can be continuously switched, and the instantaneous flow rate can be continuously derived.

Although not shown, a backlight that illuminates the rotation display unit H1b, a battery that supplies power to the camera C1, the backlight, the control device S, and the like, and a housing that surrounds the camera C1, the backlight, the control device S, and the like. Is provided.

As described above, in order for the pointer value reading unit C to function, the camera C1 as the image acquisition function unit rotates and displays as shown in FIG. 3 in order to appropriately acquire the display unit image of the rotation display unit H1b. A positioning fixing jig J for appropriately positioning the camera C1 with respect to the portion H1b is provided.
The positioning / fixing jig J positions and fixes the camera C1 to the mechanical turbine flowmeter 200 shown in FIG. 2 in the state shown in FIG.
The positioning fixing jig J includes a substrate 31 having a window portion 33 having an opening area similar to that of the display surface of the rotation display portion H1b of the analog display unit H1 and a plurality of the substrates 31 on the mechanical turbine flow meter 200. An annular flange portion 30 fixed by a bolt B, an arm portion 32 whose base end is fixed to the substrate 31 and whose tip extends in a direction orthogonal to the display surface of the rotation display portion H1b, and an arm at the tip of the arm portion 32. The position-adjustable first position adjusting mechanism XT along the first direction orthogonal to the extension direction of the portion 32 and the position-adjustable second position along the second direction orthogonal to both the extension direction and the first direction of the arm portion 32. Around the two-position adjustment mechanism YT, the rotation axis G fixed by the L-shaped jig F whose position is adjusted by the first position adjustment mechanism XT and the second position adjustment mechanism YT, and the rotation axis G. It is composed of a fixing jig KJ that rotatably fixes the camera C1.
The first position adjusting mechanism XT is configured so that the position can be adjusted in the first direction by rotating the first adjusting knob XTa, and the second position adjusting mechanism YT is configured by rotating the second adjusting knob YTa. The fixing jig KJ is configured so that the position can be adjusted in the second direction, and the camera C1 can be swung around the rotation axis G by loosening the fixing handle KH.

Further, the instantaneous flow rate measuring device 100 includes a monitor unit H2 that displays a display unit image acquired by the camera C1, and the monitor unit H2 has an arc at a substantially central portion of the display unit image acquired by the camera C1. The arcuate marker M having a shape can be displayed.
By operating the positioning fixing jig J described above, the operator arranges the arcuate marker M displayed on the monitor unit H2 so as to be superimposed on a plurality of scales displayed on the rotation display unit on the display unit image. By doing so, the positioning of the camera C1 with respect to the rotation display unit H1b is completed.

With the above configuration, the instantaneous flow rate measuring device 100 of the mechanical turbine flow meter 200 capable of deriving the instantaneous flow rate is realized.
When the flow rate of the fluid flowing through the main flow path 17 changes suddenly, the turbine rotor 14 cannot follow the sudden change of the fluid due to inertia or the like, and the flow rate of the fluid is proportional to the rotation speed of the turbine rotor 14. It may not be a relationship. In this case, the flow rate derived by the instantaneous flow rate derivation unit S1 of the control device S will be overmeasured to deviate from the actual flow rate.
Therefore, the mechanical turbine flowmeter 200 according to the embodiment is configured as follows in order to suppress the over-weighing.
The control device S evaluates the measurement performance of the instantaneous flow rate derivation unit S1 by comparing the instantaneous flow rate derived by the instantaneous flow rate derivation unit S1 with the bypass flow rate (mass flow rate) measured by the mass flow meter 21. The measurement performance evaluation unit S2 is provided. Further, an instantaneous flow rate integrated value deriving unit S3 for deriving an integrated value of the instantaneous flow rate evaluated to be appropriate by the measuring performance evaluation unit S2 is provided. Then, the instantaneous flow rate evaluated to be appropriate by the measurement performance evaluation unit S2 and the flow rate integrated value derived by the instantaneous flow rate integrated value derivation unit S3 are stored in a storage unit (not shown) and an output (not shown). It is output to the part.

As described above, the control device S includes functional parts of the specific scale extraction function unit C2, the change amount reading function unit C3, the instantaneous flow rate derivation unit S1, the measurement performance evaluation unit S2, and the instantaneous flow rate integrated value derivation unit S3. The control device S is provided in a form in which hardware such as various CPUs and memories and software cooperate with each other in order to appropriately exert these functions.

〔Example〕
Next, the measurement results (FIGS. 4 and 6) using the mechanical turbine flowmeter having the instantaneous flow rate measuring device according to the embodiment are obtained, and the measurement results using a generally known electronic turbine flowmeter (FIGS. 5 and 7) are obtained. ) Is shown in comparison with.
4 and 5, a measurement result when the flow rate was continuously switched varied between ^{0 Nm} 3 / h and 100 Nm ³ / h, 6 and 7, the flow rate of 100 Nm ³ / h and 150 Nm ³ / It is a measurement result when it is continuously switched with h and fluctuated. More specifically, the low flow rate time is about 25 seconds and the high flow rate time is about 6 seconds, and the continuous flow rate change is measured.
Incidentally, as for the measurement result, the test result (FIGS. 4 and 6) relating to the mechanical turbine flowmeter shows the value converted into the value in the standard state, and the test result relating to the electronic turbine flowmeter (FIG. 5). , 7) show the values measured in the measurement environment. Further, the non-correction guideline values of both turbines cause substantially the same over-weighing in the same measurement environment.
In the test result of the mechanical turbine flowmeter shown in FIG. 4, the overweighing was 12.57 Nm ³ , and in the test result of the electronic turbine flowmeter shown in FIG. 5, the overweighing was 5.51 m ³ (13. a 78 nm ^3), since it is substantially obtained a comparable value, in the case of switching the flow rate continuously between ^{0 Nm} 3 / h approximately and 100 Nm ³ / h about, in accordance with the embodiment tested It can be said that the result (FIG. 4) can correct the over-weighing with substantially the same accuracy as the test result (FIG. 5) with the electronic turbine flowmeter.
In the test result of the mechanical turbine flowmeter shown in FIG. 6, the overweighing was 2.31 Nm ³ , and in the test result of the electronic turbine flowmeter shown in FIG. 7, the overweight was 0.59 m ³ (1. a 48 nm ^3), since it is substantially obtained a comparable value, in the case of switching the flow rate continuously between 100 Nm ³ / h approximately and 150 Nm ³ / h about, in accordance with the embodiment tested It can be said that the result (FIG. 6) can correct the over-weighing with substantially the same accuracy as the test result (FIG. 7) with the electronic turbine flowmeter.

[Another Embodiment]
In the above embodiment, the specific scale extraction function unit C2 shows an example in which the nearest scale approaching the fixed pointer Hk is extracted as the specific scale Km, but another configuration may be adopted. ..
Specifically, the specific scale extraction function unit C2 extracts the closest scale that is separated (moving away) from the fixed pointer Hk as the specific scale Km, and the distance between the fixed pointer Hk and the specific scale Km. May be controlled to extract a new specific scale Km when is equal to or greater than a predetermined second distance.

It should be noted that the configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in other embodiments as long as there is no contradiction. The embodiments disclosed in the present specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified without departing from the object of the present invention.

The instantaneous flow rate measuring device of the present invention and the mechanical turbine flow meter provided with the device are mechanical turbine flow meters capable of appropriately measuring and outputting the instantaneous flow rate even if the instantaneous flow rate cannot be normally measured. It can be effectively used as an instantaneous flow rate measuring device and a mechanical turbine flow meter equipped with the device.

14: Turbine rotor 17: Main flow path 20: Bypass flow path 21: Mass flow meter 100: Instantaneous flow rate measuring device 200: Mechanical turbine flow meter C: Pointer value reading unit C1: Camera C2: Specific scale extraction function unit C3: Change Quantity reading function unit H1: Analog display unit H1b: Rotation display unit H2: Monitor unit H1a: First display unit Hk: Fixed pointer Hm: Scale plate Km: Specific scale L: Distance M: Arc-shaped marker S1: Instantaneous flow rate derivation unit S2: Weighing performance evaluation unit S3: Instantaneous flow rate integrated value derivation unit

Claims (8)

An analog that displays a turbine rotor that is rotatably provided in the main flow path through which the fluid passes and rotates as the fluid passes, and an integrated value of the fluid flow rate that is mechanically processed according to the rotation speed of the turbine rotor. An instantaneous flow rate measuring device for a mechanical turbine flow meter having a display unit.
The analog display unit has a rotation display unit capable of displaying a flow rate of a plurality of digits and whose scale rotates relative to a fixed pointer at the minimum digit of the plurality of digits.
The turbine rotor is based on a pointer value reading unit that continuously reads the relative positional relationship between the fixed pointer and the scale on the rotation display unit over time, and the relative positional relationship read by the pointer value reading unit. An instantaneous flow rate measuring device for a mechanical turbine flow meter equipped with an instantaneous flow rate deriving unit for deriving the instantaneous flow rate of the above. The pointer value reading unit includes an image acquisition function unit that continuously acquires a display unit image that is an image of the rotation display unit over time, and a scale that is close to the fixed pointer in the scale from the acquired display unit image. The relative positional relationship between the specific scale extraction function unit that extracts the specific scale existing in the above and the amount of change in the distance between the specific scale and the fixed pointer extracted by the specific scale extraction function unit per unit time. It has a change amount reading function unit that reads as
The instantaneous flow rate deriving unit derives the instantaneous flow rate based on the amount of change in the distance between the specific scale and the fixed pointer read by the change amount reading function unit per unit time. The instantaneous flow rate measuring device of the mechanical turbine flow meter described in. The specific scale extraction function unit extracts a scale approaching the fixed pointer as the specific scale, and when the distance between the fixed pointer and the specific scale becomes less than a predetermined first distance, The instantaneous flow rate measuring device for a mechanical turbine flow meter according to claim 2, wherein a new specific scale is extracted. The specific scale extraction function unit extracts a scale separated from the fixed pointer as the specific scale, and when the distance between the fixed pointer and the specific scale exceeds a predetermined second distance, a new scale is newly extracted. The instantaneous flow rate measuring device for the mechanical turbine flow meter according to claim 2, wherein the specific scale is extracted. A monitor unit for displaying the display unit image acquired by the image acquisition function unit is provided.
The monitor unit can display an arc-shaped arc-shaped marker at a substantially central portion of the display unit image acquired by the image acquisition function unit.
In a state where the image acquisition function unit is positioned with respect to the rotation display unit so that the arc-shaped marker is superimposed on the plurality of scales displayed on the rotation display unit, the image acquisition function unit displays the display unit image. The instantaneous flow rate measuring device for a mechanical turbine flow meter according to any one of claims 2 to 4 to be acquired. A bypass flow path connecting the upstream side portion and the downstream side portion of the turbine rotor in the flow direction of the fluid in the main flow path,
A bypass flow rate measuring unit that measures the bypass flow rate of the fluid flowing in the normal flow direction from the upstream side portion to the downstream side portion in the bypass flow path,
A claim including a measurement performance evaluation unit that evaluates the measurement performance of the instantaneous flow rate derivation unit by comparing the instantaneous flow rate derived by the instantaneous flow rate derivation unit with the bypass flow rate measured by the bypass flow rate measurement unit. Item 4. The instantaneous flow rate measuring device for the mechanical turbine flow meter according to any one of Items 1 to 5. The instantaneous flow rate measuring device for a mechanical turbine flow meter according to claim 6, further comprising an instantaneous flow rate integrated value deriving unit that derives an integrated value of the instantaneous flow rate evaluated to be appropriate by the measuring performance evaluation unit. A mechanical turbine flow meter including the instantaneous flow rate measuring device according to any one of claims 1 to 7.

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