JP4458914B2 - Residual chlorine concentration measuring instrument and method for measuring residual chlorine concentration in tap water - Google Patents

Description

  The present invention relates to a residual chlorine concentration measuring device for correcting and outputting a detection result of a residual chlorine sensor that detects a residual chlorine concentration using an oxidation-reduction reaction based on the detection result of a flow velocity sensor, and the residual chlorine sensor and the flow velocity sensor. The present invention relates to a method for measuring residual chlorine concentration in tap water.

Conventionally, in this type of residual chlorine concentration measuring device, in view of the fact that the detection accuracy of the residual chlorine sensor changes with the flow rate of tap water, the detection result of the residual chlorine sensor is corrected according to the flow rate of tap water (See Patent Document 1).
JP 2000-121605 A (Claim 1, paragraphs [0005] and [0006])

  By the way, when the applicant of the present application investigated the relationship between the detection accuracy of the residual chlorine sensor and the flow rate of tap water, the graph shown in FIG. 4 shows the difference between the detection accuracy of the residual chlorine sensor and the flow rate of tap water. A certain correspondence relationship is established. And when the flow rate of tap water changes gently, the detection accuracy of the residual chlorine sensor changes following the change of the flow rate along the graph.

  However, it has been found that when the flow rate changes at a magnitude greater than a predetermined rate of change, the detection accuracy of the residual chlorine sensor changes including the first-order lag element, and the correspondence relationship in the above graph is temporarily not established. . That is, immediately after the flow velocity changes at a magnitude greater than the predetermined rate of change, the flow velocity and the detection accuracy of the residual chlorine sensor deviate from the correspondence relationship in the above graph, and for a while after the flow velocity becomes a constant value after the change. After that, the detection accuracy of the residual chlorine sensor becomes a constant value and returns to the correspondence relationship in the above graph.

  However, in the conventional residual chlorine concentration measuring device described above, the detection result of the residual chlorine sensor is simply corrected according to the flow rate, so whether or not the flow rate has changed by a magnitude greater than a predetermined rate of change. Therefore, the state where the inaccurate residual chlorine concentration is detected cannot be distinguished from the state in which the accurate residual chlorine concentration is detected, and the reliability of the detection result is low.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a residual chlorine concentration measuring instrument and a method for measuring the residual chlorine concentration of tap water, which can obtain a detection result of residual chlorine concentration with higher reliability than before. To do.

The residual chlorine concentration measuring device according to the invention of claim 1 made to achieve the above object has a pair of electrodes arranged in a flow path through which tap water flows, and those 1 are associated with the oxidation-reduction reaction. Residual chlorine sensor that detects the residual chlorine concentration of tap water based on the current value flowing between the pair of electrodes, a flow rate sensor that detects the flow rate of tap water, and the detection result of the residual chlorine sensor based on the detection result of the flow rate sensor In the residual chlorine concentration measuring instrument provided with a data processing unit that corrects and outputs to the display device or the management center, the data processing unit stores a correction map that stores the detection error of the residual chlorine sensor in correspondence with the flow rate, When the flow velocity change rate R calculated by R = | ΔV / V | is smaller than the reference value, where V is the flow velocity detected by the flow velocity sensor and ΔV is the amount of change per unit time of the flow velocity V. , Flow velocity V and Data correction means for removing the detection error specified by the correction map from the residual chlorine concentration detected by the residual chlorine sensor, and the residual chlorine concentration detected by the residual chlorine sensor when the flow rate change rate R is larger than the reference value And a data rejecting means for prohibiting output to the display device or the management center .

  The invention according to claim 2 is characterized in that, in the residual chlorine concentration measuring instrument according to claim 1, the reference value is 0.05.

  The invention according to claim 3 is characterized in that, in the residual chlorine concentration measuring instrument according to claim 1, the reference value is 0.30.

  According to a fourth aspect of the present invention, in the residual chlorine concentration measuring instrument according to any one of the first to third aspects, the data discarding means is configured to increase a residual chlorine concentration output prohibition period according to the magnitude of the flow rate change rate R. It is characterized in that it is configured to change the height.

The residual chlorine concentration measuring instrument according to the invention of claim 5 has a pair of electrodes arranged in a flow path through which tap water flows, and a current value flowing between the pair of electrodes in accordance with the oxidation-reduction reaction. A residual chlorine sensor for detecting the residual chlorine concentration of tap water based on the flow rate sensor for detecting the flow rate of tap water, and correcting the detection result of the residual chlorine sensor based on the detection result of the flow rate sensor to display the display device or the management center In the residual chlorine concentration measuring instrument provided with a data processing unit that outputs to the data processing unit, when the flow rate obtained by the flow rate sensor is V and the change amount of the flow rate V per unit time is ΔV, P = It is characterized in that correction means for correcting the residual chlorine concentration detected by the residual chlorine sensor according to the change rate P calculated by ΔV / V is provided.

A sixth aspect of the present invention is the residual chlorine concentration measuring instrument according to any one of the first to fifth aspects, wherein the data processing unit calculates the flow rate of tap water based on the flow rate detected by the flow rate sensor, or the display device or It is characterized by being configured to output to the management center .

  According to a seventh aspect of the present invention, there is provided a method for measuring a concentration of residual chlorine in tap water, wherein a pair of electrodes provided in a residual chlorine sensor is disposed in a water pipe, and a current value flowing between the pair of electrodes in accordance with an oxidation-reduction reaction In the method for measuring the residual chlorine concentration of tap water, which detects the residual chlorine concentration of tap water and corrects the detection result of the residual chlorine sensor based on the flow rate of tap water detected by the flow rate sensor, the detection error of the residual chlorine sensor Is stored in correspondence with the flow velocity, and when the flow velocity detected by the flow velocity sensor is V and the change amount per unit time of the flow velocity V is ΔV, R = | ΔV / V | Is smaller than the reference value, the detection error specified by the flow velocity V and the correction map is removed from the residual chlorine concentration detected by the residual chlorine sensor, while the flow velocity change rate is calculated. When R is larger than the reference value, the residual chlorine concentration detected by the residual chlorine sensor is not adopted.

  The invention of claim 8 is characterized in that, in the method for measuring residual chlorine concentration of tap water according to claim 7, the reference value is 0.05.

  The invention of claim 9 is characterized in that, in the method for measuring residual chlorine concentration in tap water according to claim 7, the reference value is 0.30.

  According to a tenth aspect of the present invention, in the method for measuring the residual chlorine concentration of tap water according to any one of the seventh to ninth aspects, the residual chlorine concentration detected by the residual chlorine sensor is not determined according to the magnitude of the flow rate change rate R. It is characterized by changing the period of adoption.

  The method for measuring the residual chlorine concentration of tap water according to the invention of claim 11 is based on the value of the current flowing between the pair of electrodes due to the oxidation-reduction reaction by arranging a pair of electrodes provided in the residual chlorine sensor in the water pipe. In the method for measuring residual chlorine concentration in tap water, which detects the residual chlorine concentration of tap water and corrects the detection result of the residual chlorine sensor based on the flow rate of tap water detected by the flow rate sensor, the flow rate obtained by the flow rate sensor It is characterized in that the residual chlorine concentration detected by the residual chlorine sensor is corrected in accordance with the rate of change of.

[Invention of Claims 1, 2, 3, 4, 6]
In the residual chlorine concentration measuring device according to claim 1, when the flow rate change rate R is smaller than the reference value, an accurate residual chlorine concentration obtained by removing the detection error specified by the correction map from the residual chlorine concentration detected by the residual chlorine sensor is obtained. On the other hand, when the flow rate change rate becomes larger than the reference value, the output of the residual chlorine concentration which is inaccurate due to that is prohibited. As described above, according to the present invention, an inaccurate residual chlorine concentration detection result is eliminated, and only an accurate residual chlorine concentration detection result is output. It becomes possible to obtain. Specifically, when the reference value is set to 0.05, the frequency of outputting the detection result of the residual chlorine concentration decreases, but the reliability of the output detection result of the residual chlorine concentration increases. Invention). On the other hand, when the reference value is 0.30, the reliability is somewhat lowered, but the frequency of detection of the residual chlorine concentration is increased (the invention of claim 3). Moreover, as the flow rate of tap water increases, the time until the detection accuracy of the residual chlorine sensor reaches a steady state becomes longer. Therefore, as in the residual chlorine concentration measuring device according to claim 4, by changing the length of the output prohibition period of the residual chlorine concentration according to the magnitude of the flow rate change rate R, the useless output prohibition period is eliminated. Therefore, it is possible to efficiently select the detection result of the inaccurate residual chlorine concentration and the detection result of the accurate residual chlorine concentration. Further, as in the residual chlorine concentration measuring device according to claim 6, it is possible to measure both the residual chlorine concentration and the flow rate of tap water at one place by calculating and outputting the flow rate of tap water. It becomes possible.

[Inventions of Claims 5 and 11]
As in the inventions of claims 5 and 11, by correcting the residual chlorine concentration detected by the residual chlorine sensor according to the rate of change of the flow rate, the residual chlorine concentration of tap water whose flow rate changes momentarily is more accurate than before. It becomes possible to measure.

[Inventions of Claims 7, 8, 9, 10]
In the method for measuring the residual chlorine concentration of tap water according to claim 7, when the flow rate change rate R is smaller than the reference value, the detection error specified by the correction map is accurately removed from the residual chlorine concentration detected by the residual chlorine sensor. On the other hand, when the flow rate change rate becomes larger than the reference value, the incorrect residual chlorine concentration is not adopted. As described above, according to the present invention, an inaccurate residual chlorine concentration detection result is eliminated, and only an accurate residual chlorine concentration detection result is output. It becomes possible to obtain. Specifically, when the reference value is set to 0.05, the frequency with which the detection result of the residual chlorine concentration is adopted decreases, but the reliability of the output detection result of the residual chlorine concentration increases. Invention). On the other hand, when the reference value is set to 0.30, the reliability is somewhat lowered, but the frequency of adopting the detection result of the residual chlorine concentration is increased (invention of claim 9). Moreover, as the flow rate of tap water increases, the time until the detection accuracy of the residual chlorine sensor reaches a steady state becomes longer. Therefore, as in the residual chlorine concentration measuring instrument of claim 10, by changing the length of the period in which the residual chlorine concentration detected by the residual chlorine sensor is not adopted according to the magnitude of the flow rate change rate R, Eliminating the wasteful non-adopting period, it is possible to efficiently select the inaccurate residual chlorine concentration detection result and the accurate residual chlorine concentration detection result.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The residual chlorine concentration measuring instrument 10 of the present embodiment has an electromagnetic flow sensor 12 (corresponding to the “flow velocity sensor” of the present invention) and a residual chlorine sensor 13 attached to a pipe member 11 attached in the middle of a water pipe 50. Configured.

  As shown in FIG. 1, the electromagnetic flow sensor 12 includes an electromagnetic coil 14 that generates a magnetic flux across the pipe member 11, and a direction perpendicular to the magnetic flux inside the pipe member 11 (perpendicular to the paper surface in FIG. 1). A pair of electrodes 15 and 15 (only one electrode 15 is shown in FIG. 1) arranged opposite to each other. With this configuration, when tap water, which is a conductive fluid, flows through the pipe member 11 and crosses the magnetic flux, an electromotive force corresponding to the flow velocity is generated between the pair of electrodes 15 and 15. Then, this electromotive force is amplified by the amplifier 16 and taken into the data processing unit 30 (see FIG. 3).

  On the other hand, the residual chlorine sensor 13 is disposed downstream of the electromagnetic flow sensor 12 as shown in FIG. The residual chlorine sensor 13 has a cylindrical shape that is tapered in a stepped shape, and a tip portion projects into the pipe member 11. Specifically, as shown in FIG. 2, a distal end portion of the residual chlorine sensor 13 is provided with a sensing electrode 17 made of, for example, platinum, and a base electrode made of, for example, silver is disposed on the base end side of the sensing electrode 17. 18 is provided. Further, lead wires 20 and 21 connected to the electrodes 17 and 18 extend from the housing 19 on the base end side from the base electrode 18, and the sensing electrode 17 and the base electrode 18, the base electrode 18 and the housing 19, Are insulated by insulating members 22.

  The residual chlorine sensor 13 uses the potential difference generated between the sensing electrode 17 and the base electrode 18 or applies a constant voltage to reduce residual chlorine contained in tap water on the sensing electrode 17. The reduction current value generated at this time is amplified by the amplifier 23 and output to the data processing unit 30.

  As described above, since the residual chlorine sensor 13 and the electromagnetic flow sensor 12 are attached to the pipe member 11, it is more troublesome to attach the sensors 12 and 13 than when the sensors 12 and 13 are attached to different locations of the water pipe 50. Therefore, it is possible to measure both the residual chlorine concentration and the flow rate of tap water at one place in the middle of the water pipe 50.

  Incidentally, the data processing unit 30 includes a flow rate calculation unit 31 and a residual chlorine concentration calculation unit 32. The flow rate calculation unit 31 calculates the flow rate of tap water based on the flow velocity value detected by the electromagnetic flow rate sensor 12. Specifically, the flow rate is calculated by multiplying the flow velocity detected by the electromagnetic flow sensor 12 by the cross-sectional area S of the pipe member 11 measured in advance. And the flow volume calculated in the flow volume calculating part 31 is output to the display apparatus 40 or the management center which is not shown in figure.

  The residual chlorine concentration calculation unit 32 calculates the residual chlorine concentration based on the reduction current value by the residual chlorine sensor 13 and corrects the residual chlorine concentration calculated based on the flow velocity value detected by the electromagnetic flow sensor 12, The data is output to the display device 40 or a management center (not shown). The residual chlorine concentration calculation unit 32 stores a correction map 1 represented by the graph of FIG. That is, the correction map 1 is composed of flow velocity values and detection errors obtained in advance for each flow velocity value. And the correction value H1 is acquired based on the flow velocity value by the electromagnetic flow sensor 12 and the correction map 1, and the following program is used for the residual chlorine concentration detected by the residual chlorine sensor 13 using the acquired correction value H1. Correct by M.

  Now, the residual chlorine concentration calculating part 32 executes the program M shown in FIG.5 and FIG.6 for every predetermined period (equivalent to the unit time which concerns on this invention) for every 2 seconds, for example. In this program M, first, the flow velocity value V2 detected by the electromagnetic flow sensor 12 is acquired (S1). Next, the residual chlorine concentration Z2 detected by the residual chlorine sensor 13 is acquired (S2). Then, the flow rate change rate R1 is calculated by the following calculation formula (1) with the previous flow rate value (2 seconds before) detected by the electromagnetic flow sensor 12 and stored in the storage means (not shown) as V1. (S3).

                  R1 = | (V1-V2) / V2 | (1)

  When the flow rate change rate R1 is “0.05” which is the “reference value” of the present invention, that is, 5% or less (Yes in S4), the flow rate has not changed or the flow rate has changed. Based on the flow velocity value V2 detected by the electromagnetic flow sensor 12 and the correction map 1, the correction value H1 is acquired (S5).

  Next, the detection error is excluded from the residual chlorine concentration Z2 detected by the residual chlorine sensor 13. Specifically, the residual chlorine concentration Z2 detected by the residual chlorine sensor 13 is corrected by the correction value H1 using the following arithmetic expression (2) to obtain the residual chlorine concentration Y2 (S6).

Y2 = Z2 / (1-H1) (2)
For example, when the residual chlorine concentration detected by the residual chlorine sensor 13 is “0.45” ppm and the correction value H1 is “0.1” (10%), the residual equation is obtained by the above equation (2). The chlorine concentration Y2 is corrected to “0.5” ppm. The processes in steps S5 and S6 correspond to the “data correction unit” of the present invention.

  Then, the residual chlorine concentration Y2 corrected by the above equation (2) is output (S7), the flow velocity value V2 detected by the electromagnetic flow sensor 12, the residual chlorine concentration Z2 detected by the residual chlorine sensor 13, and the correction. The residual chlorine concentration Y2 is stored in a storage means (not shown) (S8), and this program is exited.

  On the other hand, when the flow rate change rate R1 exceeds “0.05” (5%) in Step S4 (No in S4), the residual chlorine concentration Z2 detected by the residual chlorine sensor 13 is a first-order lag element. And the correspondence relationship in the correction map 1 (graph shown in FIG. 4) is temporarily not established, so the data correction rejection process (S9) is performed. This data rejection process (S9) corresponds to the “data rejection means” of the present invention.

  Here, normally, the time until the flow rate and the detection error of the residual chlorine sensor 13 return to the correspondence relationship of the correction map 1 (graph in FIG. 4) becomes longer as the flow rate change rate R1 increases. Therefore, in the data rejection process (S9), the output prohibition time of the residual chlorine concentration by the residual chlorine sensor 13 is set according to the magnitude of the flow rate change rate R1. Specifically, as shown in FIG. 6, first, it is checked whether or not the flow rate change rate R1 is greater than “0.05” (5%) and equal to or less than “0.1” (10%) (S10). . When the flow rate change rate R1 is greater than 5% and 10% or less (Yes in S10), for example, the display device 40 displays “not measurable” and holds this state for 3 seconds (S13). . That is, the residual chlorine concentration detected by the residual chlorine sensor 13 changes including the first-order lag element due to the change in the flow rate of tap water, and the flow rate value detected by the electromagnetic flow sensor 12 and the detection error of the residual chlorine sensor are different. If the correspondence of the correction map 1 (graph shown in FIG. 4) temporarily deviates, the time until the correction map 1 (graph shown in FIG. 4) returns to the correspondence (three seconds elapse). Incorrect residual chlorine concentration Y2 calculated by correcting residual chlorine concentration Z2 is prevented from being output.

  When the flow rate change rate R1 is greater than “0.1” (10%) and equal to or less than “0.2” (20%) (No in S10 and Yes in S11), the display device 40 is “not measurable”. Is displayed for 5 seconds (S14). That is, the residual chlorine concentration Z2 is corrected and calculated until the flow velocity value and the detection error of the residual chlorine sensor 13 return to the corresponding relationship of the correction map 1 (graph of FIG. 4) (5 seconds elapses). The inaccurate residual chlorine concentration Y2 is prevented from being output.

  When the flow rate change rate R1 is greater than “0.2” (20%) and equal to or less than “0.3” (30%) (No in S11 and Yes in S12), the display device 40 displays “not measurable”. Is held for 7 seconds (S15). That is, the residual chlorine concentration Z2 is corrected and calculated until the flow velocity value and the detection error of the residual chlorine sensor 13 return to the correspondence relationship of the correction map 1 (graph of FIG. 4) (7 seconds elapses). The inaccurate residual chlorine concentration Y2 is prevented from being output.

  When the flow rate change rate R1 is larger than “0.3” (30%) (No in S12), the state where “not measurable” is displayed on the display device 40 is held for 12 seconds (S16). That is, the residual chlorine concentration Z2 is corrected and calculated until the flow velocity value and the detection error of the residual chlorine sensor 13 return to the correspondence relationship of the correction map 1 (graph of FIG. 4) (12 seconds elapses). The inaccurate residual chlorine concentration Y2 is prevented from being output.

  Thus, since the length of the output prohibition period of the residual chlorine concentration Y2 is varied according to the magnitude of the flow rate change rate R1, the useless output prohibition period is eliminated, and the inaccurate residual chlorine concentration Y2 is set. It is possible to efficiently select the detection result and the accurate detection result of the residual chlorine concentration Y2.

[Measurement experiment]
Hereinafter, a measurement experiment performed using the residual chlorine concentration measuring instrument 10 of the first embodiment will be described. The experimental method is as follows.
(A) Water whose residual chlorine concentration is adjusted to 0.5 ppm is caused to flow at a flow rate of 0.5 m / s, and the flow rate is gradually changed to 1.0 m / s over about 3 seconds. Thereafter, the flow rate is kept constant at 1.0 m / s.
(B) The flow rate is measured by the electromagnetic flow sensor 12 and the residual chlorine concentration is measured by the residual chlorine sensor 13.
(C) The relationship between the residual chlorine concentration detected by the residual chlorine sensor 13 and the flow velocity value detected by the electromagnetic flow sensor 12 and the elapsed time is graphed.

  As shown in the graph of FIG. 7, when the flow rate started to change (rise) from 0.5 m / s (after about 4 seconds), the detection result of the residual chlorine concentration Z2 by the residual chlorine sensor 13 increased rapidly. When the flow rate becomes constant at 1.0 m / s (after about 8 seconds), the residual chlorine concentration Z2 detected by the residual chlorine sensor 13 is corrected to map 1 (graph of FIG. 4) at the flow rate of 1.0 m / s. The residual chlorine concentration Z2 detected by the residual chlorine sensor 13 is specified by the correction map 1 after about 16 seconds, gradually approaching the value including the detection error (value smaller than 0.5 ppm) specified by It was found that the value approximated the value including the detection error. That is, when the flow rate changes from 0.5 m / s to 1.0 m / in about 3 seconds, the flow rate and the detection error of the residual chlorine sensor 13 are about 8 seconds after the flow rate changes and becomes constant. It has been found that the correspondence relationship of the correction map 1 (graph of FIG. 4) returns.

  In the above experiment, since the flow rate does not change for the first 4 seconds, the residual chlorine concentration calculation unit 32 uses the residual chlorine concentration Z2 detected by the residual chlorine sensor 13 as the flow rate value of the electromagnetic flow sensor 12. The correct residual chlorine concentration Y2 is output by correcting with the correction value H1 corresponding to the flow velocity of 0.5 m / s acquired based on the correction map 1.

  On the other hand, the residual chlorine concentration calculation unit 32 performs the following processing based on the residual chlorine concentration Z2 detected by the residual chlorine sensor 13 when 6 seconds have elapsed. That is, the flow rate value “0.9” m / s detected by the electromagnetic flow sensor 12 when 6 seconds have elapsed, and the flow rate value “0.5” m / s detected 2 seconds before (when 4 seconds have elapsed) From the above, the flow rate change rate R1 is calculated by the above equation (1). Here, since the flow rate change rate R1 is “0.444” (about 44%) (= | (0.5−0.9) /0.9 |), the display device 40 is “not measurable”. Is set to be displayed for 12 seconds. Then, during the period from 4 seconds to 16 seconds in FIG. 7, the output of the residual chlorine concentration Y2 obtained by correcting the residual chlorine concentration Z2 detected by the residual chlorine sensor 13 is prohibited. That is, while the flow velocity value detected by the electromagnetic flow sensor 12 and the detection error of the residual chlorine sensor 13 are out of the correspondence relationship of the correction map 1 (graph of FIG. 4) (the residual detected by the residual chlorine sensor 13). While the chlorine concentration Z2 is changed including the first-order lag element), an incorrect detection result of the residual chlorine concentration Y2 is prevented from being output.

  Thus, according to this embodiment, when the flow rate change rate R1 is smaller than the reference value (5%), the residual chlorine concentration Z2 detected by the residual chlorine sensor 13 is corrected based on the flow rate value and the correction map 1. Corrected by the value H1, an accurate residual chlorine concentration Y2 is output. On the other hand, when the flow rate change rate R1 exceeds 5%, the output of the incorrect residual chlorine concentration is prohibited for a predetermined time. The In other words, since the inaccurate residual chlorine concentration detection result is eliminated and only the accurate residual chlorine concentration Y2 detection result is output, it is possible to obtain the residual chlorine concentration detection result with higher reliability than in the past. Here, when the reference value of the flow rate change rate R1 is 5%, the frequency at which the corrected detection result of the residual chlorine concentration Y2 is output is lower than when the reference value is greater than 5%. However, the reliability of the output detection result of the residual chlorine concentration Y2 increases.

[Second Embodiment]
The residual chlorine concentration measuring instrument 70 of the second embodiment is shown in FIG. 8, and only the arrangement of the residual chlorine sensor 13 is different from the residual chlorine concentration measuring instrument 10 of the first embodiment. Specifically, in this embodiment, a through-hole is formed in a portion of the pipe member 11 facing the one electromagnetic coil 14 so that the central axis of the electromagnetic coil 14 penetrates, and a residual chlorine sensor is formed there. 13 is fixed. Specifically, the electromagnetic coils 14 are arranged on axes orthogonal to the central axis of the pipe member 11 and the central axis of the pair of electrodes 15, 15, and the residual chlorine sensor 13 includes one of the electromagnetic coils. 14 is fixed to the pipe member 11. In this way, the axial length of the pipe member 11 to which the residual chlorine sensor 13 and the electromagnetic flow sensor 12 are attached is shortened by collecting the attachment positions of the residual chlorine sensor 13 and the electromagnetic flow sensor 12. be able to.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) In the first embodiment, the reference value is “0.05” (5%), but may be “0.3” (30%), for example. In this way, as in the first embodiment, the reliability is somewhat lower than when the reference value is set to 0.05, but the frequency of detection of the residual chlorine concentration is increased.

  (2) In the first embodiment, the platinum sensing electrode 17 and the silver base electrode 18 are provided. However, the sensing electrode may be gold or carbon, and the base electrode may be silver chloride or stainless steel.

  (3) In the first embodiment, when the reference value of the flow rate change rate R1 is larger than 5%, the detection result of the residual chlorine concentration Y2 is not adopted. For example, P = ΔV / V, Based on the change rate P calculated by the following equation, the residual chlorine concentration value when the steady state is reached is estimated based on the residual chlorine concentration change curve shown in FIG. 7, and the estimated value is corrected. You may make it the structure which employ | adopts the detection result of a residual chlorine concentration.

  (4) In the first embodiment, the unit time is 2 seconds, but the number of seconds of the unit time is not limited and may be 1 second.

Sectional drawing of the residual chlorine concentration measuring device which concerns on 1st Embodiment of this invention. Front view of residual chlorine sensor Block diagram showing the electrical configuration of the residual chlorine concentration measuring instrument Graph showing the relationship between the flow velocity value and the detection error of the residual chlorine sensor Flow chart showing the program Flow chart showing data rejection process Graph showing results of measurement experiment Sectional drawing of the residual chlorine concentration measuring instrument which concerns on 2nd Embodiment

Explanation of symbols

10,70 Residual chlorine concentration measuring instrument 12 Electromagnetic flow sensor (flow velocity sensor)
13 Residual chlorine sensor 30 Data processing section

Claims (11)

Residual chlorine having a pair of electrodes arranged in a flow path through which tap water flows and detecting the residual chlorine concentration of the tap water based on the value of current flowing between the pair of electrodes in accordance with the oxidation-reduction reaction A sensor,
A flow rate sensor for detecting the flow rate of the tap water;
In a residual chlorine concentration measuring device comprising a data processing unit that corrects the detection result of the residual chlorine sensor based on the detection result of the flow rate sensor and outputs the correction result to a display device or a management center ,
In the data processing unit,
A correction map storing the detection error of the residual chlorine sensor corresponding to the flow velocity;
When the flow velocity change rate R calculated by R = | ΔV / V | is smaller than the reference value, where V is the flow velocity detected by the flow velocity sensor and ΔV is the amount of change per unit time of the flow velocity V. Data correction means for removing the detection error specified by the flow velocity V and the correction map from the residual chlorine concentration detected by the residual chlorine sensor;
Data rejection means for prohibiting output of the residual chlorine concentration detected by the residual chlorine sensor to the display device or the management center when the flow rate change rate R is larger than the reference value is provided. Residual chlorine concentration measuring instrument.   The residual chlorine concentration measuring device according to claim 1, wherein the reference value is 0.05.   The residual chlorine concentration measuring device according to claim 1, wherein the reference value is 0.30.   4. The data rejection unit is configured to change a length of an output prohibition period of the residual chlorine concentration according to a magnitude of the flow rate change rate R. 5. Residual chlorine concentration measuring instrument described in 1. Residual chlorine having a pair of electrodes arranged in a flow path through which tap water flows and detecting the residual chlorine concentration of the tap water based on the value of current flowing between the pair of electrodes in accordance with the oxidation-reduction reaction A sensor,
A flow rate sensor for detecting the flow rate of the tap water;
In a residual chlorine concentration measuring device comprising a data processing unit that corrects the detection result of the residual chlorine sensor based on the detection result of the flow rate sensor and outputs the correction result to a display device or a management center ,
According to the rate of change P calculated by P = ΔV / V, where V is the flow rate obtained by the flow rate sensor and ΔV is the amount of change in the flow rate V per unit time. A residual chlorine concentration measuring device provided with correction means for correcting the residual chlorine concentration detected by the residual chlorine sensor. The said data processing part is comprised so that the flow volume of the said tap water might be calculated based on the flow rate which the said flow rate sensor detected, and it outputs to the said display apparatus or the said management center. The residual chlorine concentration measuring instrument in any one of. A pair of electrodes provided in the residual chlorine sensor is arranged in the water pipe, and the residual chlorine concentration of tap water is detected based on the current value flowing between the pair of electrodes in accordance with the oxidation-reduction reaction, and also detected by the flow rate sensor. In the method for measuring the residual chlorine concentration of tap water, which corrects the detection result of the residual chlorine sensor based on the flow rate of the tap water,
When a correction map in which the detection error of the residual chlorine sensor is stored in correspondence with the flow velocity is created, the flow velocity detected by the flow velocity sensor is V, and the amount of change per unit time of the flow velocity V is ΔV. , R = | ΔV / V |, when the flow rate change rate R calculated by R = | ΔV / V | is smaller than a reference value, the residual error detected by the residual chlorine sensor is detected by the detection error specified by the flow rate V and the correction map. A method for measuring the residual chlorine concentration of tap water, wherein the residual chlorine concentration detected by the residual chlorine sensor is not adopted when the flow rate change rate R is larger than the reference value while being removed from the chlorine concentration.   The method for measuring a residual chlorine concentration in tap water according to claim 7, wherein the reference value is 0.05.   The method for measuring a residual chlorine concentration in tap water according to claim 7, wherein the reference value is 0.30.   The tap water according to any one of claims 7 to 9, wherein a period in which the residual chlorine concentration detected by the residual chlorine sensor is not adopted is changed according to the magnitude of the flow rate change rate R. Residual chlorine concentration measurement method. A pair of electrodes provided in the residual chlorine sensor is arranged in the water pipe, and the residual chlorine concentration of tap water is detected based on the current value flowing between the pair of electrodes in accordance with the oxidation-reduction reaction, and also detected by the flow rate sensor. In the method for measuring the residual chlorine concentration of tap water, which corrects the detection result of the residual chlorine sensor based on the flow rate of the tap water,
A method for measuring the residual chlorine concentration of tap water, wherein the residual chlorine concentration detected by the residual chlorine sensor is corrected according to the rate of change of the flow velocity obtained by the flow velocity sensor.

Images