Fluid measurement system, correction method for fluid measurement system, and installation method for load sensor for fluid measurement system

Abstract

To provide a fluid measurement system with which it is possible to measure the flow velocity of a measurement fluid with high accuracy.SOLUTION: Provided is a fluid measurement system comprising: a first load sensor and a second load sensor installed spaced apart from piping; and a measurement control unit for calculating the flow velocity of a fluid flowing in the piping on the basis of outputs from the first load sensor and second load sensor. The measurement control unit calculates said flow velocity on the basis of the distance between a first position where the output of the first load sensor is at maximum when a load is imposed upon the piping in the periphery of the position where the first load sensor is installed and a second position where the output of the second load sensor is at maximum when a load is imposed upon the piping in the periphery of the position where the second load sensor is installed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a fluid measurement system, a correction method for the fluid measurement system, and a method for installing a load sensor in the fluid measurement system. [Background technology]

[0002] Patent Document 1 discloses a method for calculating the phase composition ratio of a two-phase mixture in a pipe. Patent Document 1 discloses that the flow velocity of the two-phase mixture is calculated by using load cells arranged upstream and downstream of the pipe and comparing the measurement patterns of the load cells at two points. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2017 / 0322063 Summary of the Invention [Problem to be solved by the invention]

[0004] In a correlation flowmeter that uses a load cell (load sensor), the measurement accuracy of flow velocity may change depending on the installation conditions when the load cell (load sensor) is installed on the piping.

[0005] The present disclosure provides a fluid measurement system capable of measuring the flow velocity of a measurement fluid with high accuracy. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a fluid measurement system comprising a first load sensor and a second load sensor installed at a distance from each other on a pipe, and a measurement control unit that calculates a flow velocity of a fluid flowing through the pipe based on outputs from the first load sensor and the second load sensor, wherein the measurement control unit calculates the flow velocity based on the distance between a first position at which the output of the first load sensor is maximum when a load is applied to the pipe in the vicinity of a position where the first load sensor is installed, and a second position at which the output of the second load sensor is maximum when a load is applied to the pipe in the vicinity of a position where the second load sensor is installed. Effect of the Invention

[0007] According to the fluid measurement system of the present disclosure, the flow velocity of the measurement fluid can be measured with high accuracy. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a fluid measurement system according to this embodiment when in use. [Diagram 2] FIG. 2 is a diagram showing the overall configuration of the fluid measurement system according to this embodiment at the time of calibration. [Diagram 3] FIG. 3 is a diagram showing an output of the load sensor during calibration of the fluid measurement system according to the present embodiment. [Figure 4] FIG. 4 is a diagram for explaining the correction of the fluid measurement system according to the present embodiment. [Diagram 5] FIG. 5 is a flowchart illustrating the processing of the fluid measurement system according to the present embodiment. [Figure 6] FIG. 6 is a diagram illustrating the correction result of the fluid measurement system according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, each embodiment of the present invention will be described with reference to the accompanying drawings. Note that, in the description of the specification and drawings relating to each embodiment, components having substantially the same or corresponding functional configurations may be given the same reference numerals to omit redundant description. In addition, in order to facilitate understanding, the scale of each part in the drawings may differ from the actual scale.

[0010] <Fluid measurement system 1> FIG. 1 is a diagram showing the overall configuration of a fluid measurement system 1 according to this embodiment when in use. The fluid measurement system 1 is a system that measures the flow velocity of a fluid flowing inside a pipe P. The fluid measurement system 1 determines the flow velocity of a two-phase fluid in which a liquid and a gas are mixed, for example. An example of the two-phase fluid to be measured is a mixed fluid of hot water and steam in geothermal power generation. The fluid measurement system 1 may also determine the flow rate by multiplying the determined flow velocity by the cross-sectional area of ​​the flow path. The arrow Flow indicates the direction in which the fluid flows.

[0011] The fluid measurement system 1 includes a first load sensor 11, a second load sensor 12, and a measurement control unit 20. The fluid measurement system 1 measures the flow velocity of the fluid flowing through the pipe P using the first load sensor 11 and the second load sensor 12 attached to the pipe P.

[0012] The pipe P is, for example, spaced apart from the ground G and fixed to each of the pipe support PS1 and the pipe support PS4.

[0013] The first load sensor 11 and the second load sensor 12 are load sensors that measure the load applied to the pipe P. The load sensors are, for example, load cells.

[0014] In the fluid measurement system 1 according to this embodiment, a first load sensor 11 is installed between a pipe P and a pipe support PS2 that supports the pipe P. Then, the first load sensor 11 measures a load including the weight of the fluid in the vicinity of the first load sensor 11 of the pipe P.

[0015] In the fluid measurement system 1 according to this embodiment, the second load sensor 12 is installed between the pipe P and a pipe support PS3 that supports the pipe P. The second load sensor 12 measures a load including the weight of the fluid near the second load sensor 12 of the pipe P.

[0016] Each of the first load sensor 11 and the second load sensor 12 measures the load in real time. Then, each of the first load sensor 11 and the second load sensor 12 outputs the loads measured in time series to the measurement control unit 20 in real time.

[0017] The second load sensor 12 is installed downstream of the piping P from the first load sensor 11 at a predetermined distance (installation distance L) along the piping P. Therefore, the fluid measured by the first load sensor 11 is measured by the second load sensor 12 with a delay of the time it takes for the fluid to travel from the first load sensor 11 to the second load sensor 12. Therefore, when the measurement results of the first load sensor 11 and the second load sensor 12 are compared, the measurement result of the second load sensor 12 is measured with a delay from the measurement result of the first load sensor 11.

[0018] For example, if the fluid flowing inside the pipe P is a two-phase fluid, the mixture ratio of the two-phase fluid, for example, liquid and gas, differs depending on the location in the pipe P. If the mixture ratio of the liquid and gas differs, the weight of the fluid inside differs depending on the location in the pipe. Therefore, by measuring the load applied from the pipe P at different positions on the pipe P, the fluid measurement system 1 calculates the time it takes for the fluid to move between the first load sensor 11 and the second load sensor 12. Then, the fluid measurement system 1 determines the velocity of the fluid.

[0019] The fluid measurement system 1 calculates the time difference by which the measurement result of the second load sensor 12 is delayed relative to the measurement result of the first load sensor 11. In other words, the time difference calculated by the fluid measurement system 1 represents the time it takes for the fluid to move inside the pipe P from the first load sensor 11 to the second load sensor 12. Therefore, the fluid measurement system 1 calculates the flow velocity of the fluid by dividing the installation distance L, which is the distance along the pipe P between the first load sensor 11 and the second load sensor 12, by the calculated time difference. As will be described later, correcting the installation distance L enables high-precision measurement.

[0020] It is preferable to increase the installation distance L so that the time difference between the measurement result of the first load sensor 11 and the measurement result of the second load sensor 12 increases. However, if the installation distance L is increased, the correlation between the measurement result of the first load sensor 11 and the measurement result of the second load sensor 12 decreases, making it difficult to measure the time difference. Therefore, it is preferable to increase the installation distance L within a range in which the time difference between the measurement result of the first load sensor 11 and the measurement result of the second load sensor 12 can be measured.

[0021] The measurement control unit 20 acquires the first measurement result from the first load sensor 11 and the second measurement result from the second load sensor 12 as time-series data. Then, the measurement control unit 20 processes the acquired first measurement result and second measurement result to calculate the velocity of the fluid flowing inside the pipe P.

[0022] The measurement control unit 20 acquires, for example, waveforms of load versus time as the first measurement result and the second measurement result. Then, by comparing the waveforms, it calculates the time difference between when the load is detected by the first load sensor 11 and when the load is detected by the second load sensor 12. For example, the measurement control unit 20 uses a cross-correlation method or a dynamic time warping method when calculating the time difference.

[0023] Next, calibration of the fluid measurement system 1 according to this embodiment will be described. Fig. 2 is a diagram showing the overall configuration of the fluid measurement system 1 according to this embodiment during calibration.

[0024] When calibrating the fluid measurement system 1, the fluid measurement system 1 further includes a weight 31 that applies a load locally to the piping P, a traction device 32 that moves the weight 31 in the piping direction of the piping P, and a connecting portion 33 that connects the weight 31 and the traction device 32.

[0025] The weight 31 is placed on the upper part of the pipe P. The weight of the weight 31 applies a load to the pipe P in the direction of the arrow FL. In the fluid measurement system 1 according to the present embodiment, the weight 31 moves on the upper part of the pipe P, but the weight 31 may move inside the pipe P, i.e., the path through which the fluid flows.

[0026] The weight 31 is connected to a traction device 32 by a connection 33. The connection 33 is, for example, a cable, a wire or the like.

[0027] The traction device 32 moves the weight 31 in the direction of the arrow Aw at a constant speed (reference speed Vm (meters / second)) by pulling the connecting part 33. The traction device 32 includes, for example, a motor and a pulley that rotates in response to the rotation of the motor and winds up the connecting part 33. The traction device 32 winds up the connecting part 33 to move the weight 31 at a constant speed (reference speed Vm).

[0028] Fig. 3 is a diagram showing the output of the load sensor during calibration of the fluid measurement system 1 according to this embodiment. Fig. 3 shows the result of moving a weight 31 from the upstream side of the first load sensor 11 and recording the outputs of the first load sensor 11 and the second load sensor 12. The weight 31 moves from the first load sensor 11, passing above the first load sensor 11 and the second load sensor 12, to the downstream side of the second load sensor 12.

[0029] 3, the horizontal axis represents a predetermined time after the weight 31 passes a predetermined point upstream of the first load sensor 11, and the vertical axis represents the outputs of the first load sensor 11 and the second load sensor 12. Line La in the graph of FIG. 3 represents the output of the first load sensor 11, and line Lb represents the output of the second load sensor 12.

[0030] The upstream side refers to the upstream side of the fluid flowing through the pipe P. For example, it is the left side of the paper in Fig. 1. When the direction of the fluid flowing through the pipe P changes, it is, for example, a side that is assumed to be the upstream side due to settings in the fluid measurement system 1.

[0031] 3, when the weight 31 is moved from the upstream side of the first load sensor 11 to the downstream side of the second load sensor 12, the output of the first load sensor 11 gradually increases, reaches a maximum, and then gradually decreases. The output of the second load sensor 12, delayed from the output of the first load sensor 11, gradually increases, reaches a maximum, and then gradually decreases.

[0032] The time when the outputs of the first load sensor 11 and the second load sensor 12 reach their maximums is assumed to be the time when the weight 31 is directly above the first load sensor 11 and the second load sensor 12, respectively. On the other hand, depending on the installation state of the piping P, due to the deformation mode of the piping P, the time when the outputs of the first load sensor 11 and the second load sensor 12 reach their maximums may shift from the time when the weight 31 is directly above the first load sensor 11 and the second load sensor 12, respectively.

[0033] Fig. 4 is a diagram showing typically the output of the load sensor during calibration of the fluid measurement system 1 according to this embodiment. Fig. 4 is a diagram showing typically the output of each of the first load sensor 11 and the second load sensor 12 when the weight 31 is moved from the upstream side of the first load sensor 11.

[0034] The horizontal axis of the graph in Fig. 4 represents a predetermined time after the weight 31 passes a predetermined point upstream of the first load sensor 11, and the vertical axis represents the outputs of the first load sensor 11 and the second load sensor 12. Line Las of the graph in Fig. 4 represents the ideal output of the first load sensor 11, and line Lbs represents the ideal output of the second load sensor 12. Line Lam of the graph in Fig. 4 represents the output simulating the actual output of the first load sensor 11, and line Lbm represents the output simulating the actual output of the second load sensor 12.

[0035] Ideally, the output of the first load sensor 11 is maximum when the weight 31 is located directly above the first load sensor 11. Also, ideally, the output of the second load sensor 12 is maximum when the weight 31 is located directly above the second load sensor 12.

[0036] The transit time T1 (seconds), which is the time difference between the time when the output (line Las) of the first load sensor 11 is maximized and the time when the output (line Lbs) of the second load sensor 12 is maximized, is expressed by the following formula 1. Note that the installation distance between the first load sensor 11 and the second load sensor 12 is L (meters).

[0037] T1= L / Vm (Formula 1)

[0038] However, depending on the installation conditions of the piping and the load sensors, the time when the output of the first load sensor 11 becomes maximum may shift from the time when the weight 31 is located directly above the first load sensor 11. For example, in Fig. 4, the output of the first load sensor 11 (line Lam) becomes maximum at a time earlier than the ideal maximum time. Also, the output of the second load sensor 12 (line Lbm) becomes maximum at a time later than the ideal maximum time.

[0039] Therefore, the passage time T2, which is the time difference between the time when the output (line Lam) of the first load sensor 11 is maximum and the time when the output (line Lbm) of the second load sensor 12 is maximum, is different from the passage time T1. If the passage time T1 and the passage time T2 are different, an error will occur in the flow velocity result measured by the fluid measurement system 1.

[0040] Therefore, in the fluid measurement system 1 of this embodiment, the calculation of the flow velocity is corrected using the difference in time at which the outputs of the first load sensor 11 and the second load sensor 12 reach their maximum when a load is applied along the piping P.

[0041] Fig. 5 is a flowchart illustrating the processing of the fluid measurement system 1 according to this embodiment, that is, the correction method of the fluid measurement system 1. Fig. 5 shows the processing performed by the measurement control unit 20 of the fluid measurement system 1.

[0042] (Step S10) First, the measurement control unit 20 measures the transit time between the sensors for a reference measurement object. In the fluid measurement system 1 according to this embodiment, the reference measurement object is a weight 31. The traction device 32 is an example of a drive unit that moves the reference measurement object.

[0043] As shown in Fig. 2, an operator installs a weight 31 and a traction device 32 on the pipe P. When installing, the weight 31 is installed on the upstream side of the first load sensor 11 at a fixed distance from the first load sensor 11. The traction device 32 is installed on the downstream side of the second load sensor 12 at a fixed distance. By installing the weight 31 and the traction device 32 at a fixed distance from the first load sensor 11 and the second load sensor 12, respectively, it is possible to make the weight 31 move at a constant speed (reference speed Vm) when passing near the first load sensor 11 and the second load sensor 12.

[0044] Then, the measurement control unit 20 causes the towing device 32 to tow the weight 31 at a constant speed (reference speed Vm). The measurement control unit 20 records the outputs of the first load sensor 11 and the second load sensor 12 in real time. The measurement control unit 20 records the outputs of the first load sensor 11 and the second load sensor 12 until the weight 31 passes the first load sensor 11 and the second load sensor 12 and travels a constant distance.

[0045] While moving, the weight 31 applies a load to the pipe P in the vicinity of the positions where the first load sensor 11 and the second load sensor 12 are installed. When the weight 31 applies a load to the pipe P, the outputs of the first load sensor 11 and the second load sensor 12 change.

[0046] Ideally, when the weight 31 is directly above the first load sensor 11, the output of the first load sensor 11 is maximum. However, depending on the installation conditions of the piping, the position where the output of the first load sensor 11 is maximum may be different from the position directly above the first load sensor 11. When a load is applied to the piping P by the weight 31, the position where the output of the first load sensor 11 is maximum is referred to as the first position.

[0047] Ideally, the output of the second load sensor 12 is maximum when the weight 31 is directly above the second load sensor 12. However, depending on the installation conditions of the piping, the position where the output of the second load sensor 12 is maximum may differ from the position directly above the second load sensor 12. The position where the output of the second load sensor 12 is maximum when a load is applied to the piping P by the weight 31 is referred to as the second position.

[0048] The measurement control unit 20 calculates the passing time T2 of the weight 31 from when the output of the first load sensor 11 becomes maximum to when the output of the second load sensor 12 becomes maximum, based on the measured outputs of the first load sensor 11 and the second load sensor 12. That is, the measurement control unit 20 calculates the passing time T2 based on the time it takes for the weight 31 to move from the first position where the output of the first load sensor 11 becomes maximum to the second position where the output of the second load sensor 12 becomes maximum.

[0049] Through the above process, the measurement control unit 20 measures the passing time T2 for the weight 31, which is the reference measurement object, to pass between the first load sensor 11 and the second load sensor 12.

[0050] (Step S20) Next, the measurement control unit 20 judges whether the absolute value of the difference between the measured passing time and the passing time calculated from the actual installation distance is equal to or greater than a reference value. The measurement control unit 20 calculates the passing time T1 between the first load sensor 11 and the second load sensor 12 from the installation distance L indicating the distance between the first load sensor 11 and the second load sensor 12 inputted, for example, via a setting screen or the like. Specifically, the passing time T1 is calculated by the above-mentioned formula 1.

[0051] Then, the measurement control unit 20 judges whether the absolute value of the difference between the measured passing time T2 and the passing time T1 calculated from the actual installation distance is equal to or greater than a predetermined reference value. If the absolute value of the difference between the measured passing time T2 and the passing time T1 calculated from the actual installation distance is equal to or greater than the predetermined reference value (Yes in step S20), the measurement control unit 20 judges that the error occurring in the fluid measurement system 1 is large. Therefore, the measurement control unit 20 proceeds to step S30 to perform a correction process.

[0052] On the other hand, if the absolute value of the difference between the measured passing time T2 and the passing time T1 calculated from the actual installation distance is smaller than the predetermined reference value (No in step S20), the measurement control unit 20 determines that the error occurring in the fluid measurement system 1 is small. Therefore, the measurement control unit 20 performs normal flow rate measurement without performing correction processing.

[0053] (Step S30) Next, the measurement control unit 20 calculates the set value of the sensor distance from the measured passing time. The measurement unit obtains the set value of the sensor distance Lc (meters) from the passing time T2 (seconds) by the following formula 2.

[0054] Lc = Vm×T2 (Formula 2)

[0055] The set value Lc of the inter-sensor distance corresponds to the distance between the first position where the output of the first load sensor 11 is maximum and the second position where the output of the second load sensor 12 is maximum.

[0056] (Step S40) Next, the measurement control unit 20 measures the flow velocity using the calculated sensor distance setting value Lc. Specifically, if the time difference between the outputs of the first load sensor 11 and the second load sensor 12 measured by the measurement control unit 20 is ΔT (seconds), the calculated measured flow velocity Vc (meters / second) is expressed by Equation 3.

[0057] Vc = Lc / ΔT (Equation 3)

[0058] The result of the correction will be described. FIG. 6 is a diagram for explaining the correction result of the fluid measurement system 1 according to this embodiment. FIG. 6 shows the result of measurement by the fluid measurement system 1 when the weight 31 is moved at a set speed. The measurement was performed for a plurality of inter-sensor distances. The black circle point D1 is the result of measuring the speed while performing correction in the fluid measurement system 1. The white circle point Dz is the result of measuring the speed without performing correction in the fluid measurement system 1. The straight line in the graph of FIG. 6 indicates that the set speed and the measured speed are equal, and the dotted line indicates the range of error ±10%.

[0059] 6, in the fluid measurement system 1, by performing correction (point D1), it was possible to measure the velocity with an error of approximately 10%. On the other hand, when correction was not performed (point Dz), an error of about 30% could occur depending on the conditions.

[0060] <Actions and Effects> The fluid measurement system 1 according to this embodiment moves a reference measurement object and performs measurement using the first load sensor 11 and the second load sensor 12. The fluid measurement system 1 can reduce errors in velocity measurement by using the positions at which the outputs of the first load sensor 11 and the second load sensor 12 are maximum using the moving measurement unit. Specifically, errors in flow velocity can be reduced by correcting the distances between the positions at which the outputs of the first load sensor 11 and the second load sensor 12 are maximum as the installation distances of the sensors.

[0061] <Modification> In the fluid measurement system 1 according to the present embodiment, the correction is performed using the set value Lc of the sensor distance, but the correction method is not limited to the set value Lc. For example, the first load sensor 11 may be moved to a first position where the output of the first load sensor 11 is maximum, and the second load sensor 12 may be moved to a second position where the output of the second load sensor 12 is maximum, and the first load sensor 11 and the second load sensor 12 may be installed again.

[0062] That is, as a method of installing the first load sensor and the second load sensor (load sensors) of the fluid measurement system 1, first, a step of calculating a first position where the output of the first load sensor is maximum and a second position where the output of the second load sensor is maximum is performed, followed by a step of reinstalling the first load sensor 11 at the first position and a step of reinstalling the second load sensor 12 at the second position.

[0063] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0064] 1 Fluid Measurement System 11 First load sensor 12 Second load sensor 20 Measurement control section 31 Weight 32 Traction device

Claims

1. a first load sensor and a second load sensor installed separately on the pipe; a measurement control unit that calculates a flow velocity of the fluid flowing through the pipe based on outputs from the first load sensor and the second load sensor; Equipped with the measurement control unit calculates the flow velocity based on a distance between a first position where an output of the first load sensor is maximum when a load is applied to the piping in the vicinity of a position where the first load sensor is installed, and a second position where an output of the second load sensor is maximum when a load is applied to the piping in the vicinity of a position where the second load sensor is installed. Fluid measurement system.

2. the measurement control unit calculates the distance based on a distance between the first position where an output of the first load sensor is maximized and the second position where an output of the second load sensor is maximized when a load is applied to the piping by the reference object to be measured while moving the reference object to be measured at a constant speed; The fluid measurement system of claim 1 .

3. the measurement control unit calculates the distance based on a passing time which is a time difference between when the output of the first load sensor becomes maximum and when the output of the second load sensor becomes maximum. The fluid measurement system of claim 2 .

4. The measurement control unit calculates the distance based on the product of the passing time and the constant speed. The fluid measurement system of claim 3 .

5. a first load sensor and a second load sensor installed separately on the pipe; a measurement control unit that calculates a flow velocity of the fluid flowing through the pipe based on outputs from the first load sensor and the second load sensor; A reference measurement object; A drive unit that moves the measurement object at a constant speed; Equipped with the measurement control unit calculates the flow velocity based on a distance between a first position at which an output of the first load sensor is maximum when the measurement object is loaded on the piping by the measurement object and a second position at which an output of the second load sensor is maximum when the measurement object is loaded on the piping by the measurement object when the drive unit moves the measurement object. Fluid measurement system.

6. The object to be measured moves in the upper part of the pipe. A fluid measurement system according to any one of claims 2 to 5.

7. The object to be measured moves inside the pipe. A fluid measurement system according to any one of claims 2 to 5.

8. a first load sensor and a second load sensor installed separately on the pipe; a measurement control unit that calculates a flow velocity of the fluid flowing through the pipe based on outputs from the first load sensor and the second load sensor; A method for correcting a fluid measurement system comprising: a step of the measurement control unit calculating a distance between a first position where an output of the first load sensor is maximum when a load is applied to the piping in the vicinity of a position where the first load sensor is installed, and a second position where an output of the second load sensor is maximum when a load is applied to the piping in the vicinity of a position where the second load sensor is installed; The measurement control unit calculates the flow velocity based on the distance; Including, A method for calibrating a fluid measurement system.

9. a first load sensor and a second load sensor installed separately on the pipe; a measurement control unit that calculates a flow velocity of the fluid flowing through the pipe based on outputs from the first load sensor and the second load sensor; A reference measurement object; A drive unit that moves the measurement object at a constant speed; A method for correcting a fluid measurement system comprising: a step of calculating a distance between a first position where an output of the first load sensor is maximum and a second position where an output of the second load sensor is maximum when a load is applied to the piping by the object to be measured by the drive unit when the object to be measured is moved by the drive unit; The measurement control unit calculates the flow velocity based on the distance; Including, A method for calibrating a fluid measurement system.

10. a first load sensor and a second load sensor installed separately on the pipe; a measurement control unit that calculates a flow velocity of the fluid flowing through the pipe based on outputs from the first load sensor and the second load sensor; A method for installing a load sensor in a fluid measurement system comprising: calculating a first position where an output of the first load sensor is maximum when a load is applied to the piping in the vicinity of a position where the first load sensor is installed, and a second position where an output of the second load sensor is maximum when a load is applied to the piping in the vicinity of a position where the second load sensor is installed; reinstalling the first load sensor at the first location; reinstalling the second load sensor at the second location; Including, How to install a load sensor in a flow measurement system.

Images