JP6031170B1 - Flow rate measurement method - Google Patents

Abstract

A flow rate measurement method capable of improving the accuracy of flow rate measurement without incurring costs is provided. A flow rate measurement method includes a pulse cycle acquisition step S1, a pulse cycle storage step S2, an abnormal pulse generation presence / absence determination step S3, and a flow rate measurement processing step S5. In the pulse cycle acquisition step S1, the time of one pulse of the flow rate signal within a predetermined time is measured to acquire the pulse cycle. In the pulse cycle storage step S2, the pulse cycle is stored as a pulse cycle storage variable. In the abnormal pulse generation presence / absence determination step S3, the presence / absence of an abnormal pulse is determined from the pulse cycle storage variable. In the abnormal pulse generation presence / absence determination step S3, the calculated value calculated from the threshold value determination function, which is a function of the determination threshold value determination reference variable, is compared with the pulse period storage variable. Only the flow measurement processing step S5 is performed. [Selection] Figure 2

Description

  The present invention relates to a flow rate measuring method performed by a counting unit provided in a flow meter such as a volumetric flow meter.

  As the volumetric flow meter, for example, the one disclosed in Patent Document 1 proposed by the applicant of the present application is known. Hereinafter, the configuration and structure of a conventional positive displacement meter will be described with reference to the drawings.

  In FIG. 4, the volumetric flow meter 101 includes a main body 102 and a counting unit 103 attached to the main body 102. As shown in FIG. 5, the volumetric flow meter 101 is attached in the middle of the pipe 104, measures the fluid to be measured flowing inside the pipe 104, and calculates and displays the flow rate inside the counting unit 103. It is a flow meter that can do. The display is performed by the display unit 105 described later.

  In FIG. 5, a strainer 107 is provided between the upstream pipe 104 and the upstream flange 106 of the main body 102. Reference numeral 108 in FIG. 5 indicates a bypass pipe. Reference numeral 109 indicates a valve. The bypass pipe 108 is provided as a part used when the volumetric flow meter 101 is disassembled and inspected.

  4 and 6, the main body 102 includes a front lid 113 to which the mounting base 112 of the counting unit 103 is attached, a measuring chamber forming unit 115 having a measuring chamber 114, and a rotor shaft 116 housed in the measuring chamber 114. , 116 and two rotors 117 and 118, and an upstream flange 106 and a downstream flange 110 that are continuous with the measuring chamber forming portion 115. The front lid portion 113 is formed as a member that covers the measuring chamber 114 in a state in which the rotors 117 and 118 are rotatably accommodated. Such a front lid portion 113 is fixed to the measuring chamber forming portion 115 with a screw 119.

  The rotor 117 is provided with two magnets 122 having an S pole and an N pole. The two magnets 122 are spaced apart as shown. The two magnets 122 are detected by a detection unit housed in the recess 123 of the front lid 113, that is, a flow rate detection unit (not shown) of the counting unit 103.

  Reference numeral 127 indicates a pulse transmitter. The pulse transmitter 127 is connected to, for example, an F / I converter and an integrator (not shown) via the output cable 128. The F / I converter and the integrator are installed in a remote management room, for example.

  The display body unit 124 includes a unit case 129, a substrate on which the display unit 105 is mounted, and a battery (not shown) for supplying power to the substrate. The substrate is housed in the unit case 129 and fixed with screws. The battery is also stored in the unit case 129. The cover 125 includes a transparent visual recognition unit 130 that faces the display unit 105 and operation switches 131 and 132.

JP 2007-47018 A

  In the above prior art, the rotors 117 and 118 may swing (reciprocate) due to the fluid to be measured. In this case, an abnormal pulse is generated, and as a result, there is a problem that the flow rate measurement is performed in a state including the abnormal pulse that does not contribute to the actual flow rate.

  There is no doubt that a significant increase in cost will result if the above-mentioned oscillation is improved in terms of hardware. Therefore, the present inventor intends to improve the software.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a flow rate measurement method capable of improving the accuracy of flow rate measurement without incurring costs.

The flow rate measurement method of the present invention according to claim 1, which has been made to solve the above-mentioned problem, measures a time of one pulse of a flow rate signal within a predetermined time to acquire a pulse cycle, and
A pulse period storage step for storing the pulse period as a variable for pulse period storage;
Abnormal pulse occurrence presence / absence determination step for determining whether or not an abnormal pulse has occurred from the pulse period storage variable;
Including a flow rate measurement processing step for performing flow rate calculation processing for flow rate measurement,
In the abnormal pulse generation presence / absence determination step, the calculated value calculated from the threshold value determining function that is a function of the determination threshold value determining reference variable is compared with the pulse period storage variable to determine that the abnormal pulse is not generated. Only in the case of, it moves to the flow measurement processing step ,
In the flow rate measurement processing step, the pulse period storage variable is used as the determination threshold value determination reference variable, and a value obtained by dividing the determination threshold value determination reference variable by n (an integer equal to or greater than 2) is the calculated value. It is used as .

The present invention described in claim 2 is the flow rate measuring method according to claim 1, in the case of the determination that the abnormal pulse is generated, it performs abnormality generation process, and outputs the effect that the abnormal pulse is generated It shifts to the pulse invalidity determination step .

According to the first aspect of the present invention, the pulse period is obtained by measuring the time of one pulse of the flow rate signal within a predetermined time, and the pulse period is stored as a pulse period storage variable. Thus, it is possible to determine whether or not an abnormal pulse has occurred using the stored pulse period storage variable. Specifically, the presence or absence of an abnormal pulse can be determined by comparing the stored pulse cycle storage variable with the calculated value calculated from the threshold value determining function or the threshold value. For example, if the pulse cycle storage variable falls below the calculated value or threshold value, it can be determined that an abnormal pulse has occurred, and if an abnormal pulse has occurred, flow measurement is performed using the corresponding flow signal. Do not do it.
As described above, according to the present invention, since it is an improvement in software, there is an effect that it can be improved without incurring costs. Further, if the flow measurement processing step is performed only when an abnormal pulse is not generated and the flow rate calculation processing for the flow rate measurement is performed, the accuracy of the flow rate measurement can be significantly improved as compared with the conventional case. There is an effect.
Furthermore, according to the present invention, there is an effect that it is possible to provide an example of better determining whether or not an abnormal pulse has occurred.

  According to the present invention described in claim 2, in addition to the effect of claim 1, the following effect is further exhibited. That is, there is an effect that the user can be notified that an abnormal pulse has occurred.

It is a block diagram which shows the structure of the flow volume detection part by which the flow volume measuring method of this invention is employ | adopted (Example 1). It is a flowchart which concerns on the flow volume measuring method of this invention (Example 1). It is a flowchart which concerns on the flow volume measuring method of this invention used as another example (Example 2). It is a perspective view of the volumetric flow meter of a prior art example. It is a perspective view of the state which attached the volumetric flow meter of Drawing 4 in the middle of piping. It is a disassembled perspective view of the main-body part in the positive displacement flowmeter of FIG.

  A flow rate measurement method employed in a flow meter such as a volumetric flow meter includes a pulse cycle acquisition step, a pulse cycle storage step, an abnormal pulse occurrence presence / absence determination step, and a flow rate measurement processing step. In the pulse period acquisition step, the pulse period is acquired by measuring the time of one pulse of the flow rate signal within a predetermined time. In the pulse cycle storage step, the pulse cycle is stored as a pulse cycle storage variable. In the abnormal pulse generation presence / absence determination step, the presence / absence of occurrence of an abnormal pulse is determined from the pulse cycle storage variable. In the flow rate measurement processing step, flow rate calculation processing for flow rate measurement is performed. In the flow rate measurement method of the present invention including each step as described above, in the abnormal pulse generation presence / absence determination step, a calculated value calculated from a threshold determination function that is a function of a determination threshold determination reference variable, or a predetermined value is determined in advance. The threshold value is compared with the pulse cycle storage variable, and only when it is determined that an abnormal pulse has not occurred, the flow shifts to the flow measurement processing step.

  Embodiment 1 will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a flow rate detector in which the flow rate measurement method of the present invention is employed. FIG. 2 is a flowchart according to the flow rate measuring method of the present invention. In addition, the same code | symbol is attached | subjected to the same component fundamentally as a prior art example, and detailed description is abbreviate | omitted.

  In FIG. 1, for example, the volumetric flow meter includes a flow rate detection unit 1 and a counting unit 2. The flow rate detection unit 1 includes rotors 3 and 4 and a sensor unit 5. The rotors 3 and 4 are basically the same as the rotors 117 and 118 disposed in the conventional measuring chamber 114 (see FIG. 6). The rotors 3 and 4 are arranged so as to rotate in proportion to the volume of the fluid to be measured (rotate in proportion to the flow rate). The sensor unit 5 is disposed at a position facing the rotors 3 and 4. The sensor unit 5 is provided for detecting the magnet 6 provided on the rotor 3. In other words, it is provided to detect the flow signal. In addition, the number of the magnets 6 in a figure shall be an example. In addition, the method for detecting the flow rate signal is the same as that in the prior art. The sensor unit 5 is connected to a control unit 7 described later via a signal line.

  The counting unit 2 includes a control unit 7, a calculation unit 8, a storage unit 9, and an output unit 10. The control part 7 is provided as a part which performs various controls including the flow rate measuring method of the present invention. The control unit 7 is a so-called CPU, and a calculation unit 8, a storage unit 9, and an output unit 10 are connected to the control unit 3. The control unit 7 has a timer (not shown).

  The arithmetic unit 8 is provided as a part that performs various arithmetic processes. According to the present invention, the calculation unit 8 performs flow rate calculation processing for flow rate measurement. The storage unit 9 stores variables such as a pulse period to be described later. Further, as described later in the second embodiment, a threshold value and the like are also stored (stored for setting in advance).

  The output unit 10 corresponds to a display unit, a pulse transmitter (see reference numerals 105 and 127 in FIG. 4), etc., and in terms of the present invention, the output unit 10 notifies the user that an abnormal pulse has occurred, or one-shot related to the flow rate. The pulse is configured to be output to the outside.

  The flow rate measuring method of the present invention includes the steps shown in FIG. Then, after these steps, for example, an accurate flow rate integrated value can be displayed. The flow rate measuring method of the present invention can display an accurate integrated flow rate even when the rotors 3 and 4 are swung (reciprocating) by the fluid to be measured, for example. Hereinafter, the flow rate measuring method of the present invention will be described.

  In FIG. 2, step S1 shows a pulse period acquisition step. In this pulse cycle acquisition step S1, a timer (not shown) of the control unit 7 (see FIG. 1) is operated to measure the time of one pulse of the flow rate signal within a predetermined time, and the pulse cycle is acquired from this measured value. Processing is performed. After obtaining the pulse period, the process proceeds to the next step.

  Step S2 shows a pulse period storage step. In this pulse cycle storage step S2, processing for storing the pulse cycle acquired in the pulse cycle acquisition step S1 in the storage unit 9 (see FIG. 1) as a pulse cycle storage variable, that is, processing for storing the pulse cycle in Period is performed. (Period = pulse period). After the pulse period is stored in Period as a pulse period storage variable, the process proceeds to the next step.

  Step S3 shows an abnormal pulse generation presence / absence determination step. In this abnormal pulse generation presence / absence determination step S3, a process of determining whether or not an abnormal pulse has occurred due to the swinging of the rotors 3 and 4 (see FIG. 1) (a process of determining whether or not an abnormal pulse has occurred) is performed. Is called. Specifically, processing for comparing the pulse cycle storage variable (Period) stored in the pulse cycle storage step S2 with the calculated value calculated from the threshold value determining function (f (Base)) is performed. . The calculated value calculated from the threshold value determining function f (Base) is a value obtained by dividing a determination threshold value determining reference value variable (to be described later) in this embodiment by n (n is an integer equal to or greater than 2). (F (Base) = Base / n).

  In the abnormal pulse generation presence / absence determination step S3, if Period> f (Base) is YES, the pulse is determined to be valid (the flow rate signal is valid), and the process proceeds to the next step S4. On the other hand, in the case of NO where Period> f (Base) is not satisfied, it is determined that the pulse is invalid (an abnormal pulse has occurred due to oscillation), and the process proceeds to step S6.

  Step S4 shows a reference value variable storing step. In this reference value variable storage step S4, a rewrite process (Base = Period) is performed to use the pulse period storage variable Period as the determination threshold value determination reference value variable Base. The rewritten determination threshold value determination reference value variable Base is stored in the storage unit 9 (see FIG. 1). After rewriting the determination threshold value reference value variable Base, the process proceeds to the next step.

  Step S5 shows a flow rate measurement processing step. In this flow rate measurement processing step S5, flow rate calculation processing for flow rate measurement is performed. Note that the flow rate calculation process is the same as in the prior art, and for example, a one-shot pulse output via the output unit 10 (see FIG. 1) is generated. When the flow rate measurement processing step S5 ends, the process proceeds to the pulse period acquisition step S1.

  Step S6 shows a pulse invalidity determination step. In this pulse invalidity determination step S6, a process is performed in which an abnormal pulse is generated and displayed on a display unit (not shown) to notify the user. When the pulse invalidity determination step S6 ends, the process proceeds to the pulse period acquisition step S1.

  As described above with reference to FIGS. 1 and 2, according to the present invention, it is possible to determine whether or not an abnormal pulse has occurred. Specifically, the presence or absence of the occurrence of an abnormal pulse can be determined by comparing the stored pulse period storage variable Period with the calculated value calculated from the threshold value determining function f (Base). If it is determined that an abnormal pulse has occurred, the flow rate may not be measured with the corresponding flow rate signal. This is a process in which filtering is performed.

  According to the present invention, since it is an improvement in terms of software, there is an effect that it can be improved without incurring costs. Further, since the flow measurement processing step S5 is performed only when no abnormal pulse occurs and the flow rate calculation processing for the flow rate measurement is performed, the original flow rate can be measured, resulting in the accuracy of the flow rate measurement. Can be improved significantly compared to the prior art.

  Embodiment 2 will be described below with reference to the drawings. FIG. 3 is a flowchart according to another example of the flow rate measuring method of the present invention.

  Another example of the flow rate measuring method of the present invention includes the steps shown in FIG. After these steps, an accurate integrated flow value can be displayed. Hereinafter, another example of the flow rate measuring method of the present invention will be described.

  In FIG. 3, step S11 shows a pulse period acquisition step. In this pulse cycle acquisition step S11, the same processing as the pulse cycle acquisition step S1 in FIG. 2 is performed. After obtaining the pulse period, the process proceeds to the next step.

  Step S12 shows a pulse period storage step. In this pulse cycle storage step S12, the same processing as the pulse cycle storage step S2 of FIG. 2 is performed. After the pulse period is stored in Period as a pulse period storage variable, the process proceeds to the next step.

  Step S13 shows an abnormal pulse generation presence / absence determination step. In this abnormal pulse generation presence / absence determination step S13, processing for determining whether or not an abnormal pulse has occurred due to the swinging of the rotors 3 and 4 (see FIG. 1) (processing for determining whether or not an abnormal pulse has occurred) is performed. Is called. Specifically, processing for comparing the pulse cycle storage variable (Period) stored in the pulse cycle storage step S12 with a predetermined threshold (Threshold) is performed. The threshold Threshold is always constant and is stored in the storage unit 9 (see FIG. 1). In addition, it turns out that the reference value variable storage step S4 of FIG. 2 becomes unnecessary by using the threshold Threshold. Therefore, it is needless to say that a simple flow rate measuring method can be provided.

  In the abnormal pulse generation presence / absence determination step S13, if Period> Threshold is YES, the pulse is determined to be valid (the flow rate signal is valid), and the process proceeds to the next step S14. On the other hand, if NO is not Period> Threshold, it is determined that the pulse is invalid (an abnormal pulse has occurred due to oscillation), and the process proceeds to step S15.

  Step S14 shows a flow rate measurement processing step. In this flow measurement process step S14, the same process as the flow measurement process step S5 of FIG. 2 is performed. When the flow rate measurement processing step S14 ends, the process proceeds to the pulse period acquisition step S11.

  Step S15 shows a pulse invalidity determination step. In this pulse invalidity determination step S15, the same processing as in the pulse invalidity determination step S6 of FIG. 2 is performed. When the pulse invalidity determination step S15 ends, the process proceeds to a pulse period acquisition step S11.

  As described above, as described with reference to FIG. 3, it can be seen that Example 2 also has the same effect as Example 1. That is, there is an effect that it can be improved without cost. In addition, there is an effect that the accuracy of the flow rate measurement can be significantly improved as compared with the prior art.

  In addition, the present invention can of course be modified in various ways within the scope not changing the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Flow rate detection part 2 ... Counting part 3, 4 ... Rotor 5 ... Sensor part 6 ... Magnet 7 ... Control part 8 ... Calculation part 9 ... Memory | storage part 10 ... Output part

Claims (2)

A pulse period acquisition step of measuring the time of one pulse of the flow rate signal within a predetermined time and acquiring a pulse period;
A pulse period storage step for storing the pulse period as a variable for pulse period storage;
Abnormal pulse occurrence presence / absence determination step for determining whether or not an abnormal pulse has occurred from the pulse period storage variable;
Including a flow rate measurement processing step for performing flow rate calculation processing for flow rate measurement,
In the abnormal pulse generation presence / absence determination step, the calculated value calculated from the threshold value determining function that is a function of the determination threshold value determining reference variable is compared with the pulse period storage variable to determine that the abnormal pulse is not generated. Only in the case of, it moves to the flow measurement processing step ,
In the flow rate measurement processing step, the pulse period storage variable is used as the determination threshold value determination reference variable, and a value obtained by dividing the determination threshold value determination reference variable by n (an integer equal to or greater than 2) is the calculated value. A flow rate measuring method characterized by being used as : The flow rate measurement method according to claim 1,
It said abnormal pulse occurs in the case of determination performs abnormality generation process, the flow rate measuring method characterized in that transitions to pulse cancellation determination step of outputting the effect that the abnormal pulse is generated.

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