JP5939668B2 - Impeller flow meter self-diagnosis device - Google Patents

Description

  The present invention relates to a self-diagnosis device for an impeller-type flow meter that measures the flow rate of a fluid based on the rotation amount of the impeller.

  When this type of impeller-type flow meter is used for a long period of time, the rotational resistance of the impeller increases due to wear of the rotation support part of the impeller or adhesion of impurities in the fluid of the impeller, etc. Measurement accuracy deteriorates. On the other hand, an impeller-type flow meter that can be maintained by removing the impeller is known (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 08-62017 (see FIG. 1)

  By the way, in the conventional impeller-type flow meter, the maintenance was performed on the condition that a predetermined use guarantee period elapses. However, the increasing speed of the impeller rotational resistance and the accompanying deterioration in flow rate measurement accuracy vary depending on the use environment of the impeller flow meter and variations in durability performance. For this reason, the use guarantee period is normally set to a short period including a margin, and in actuality, even though the flow rate can be measured with sufficient accuracy, excessive maintenance is performed. , That effort and expense could be wasted. On the other hand, for example, when an accuracy test is performed by flowing a predetermined constant flow rate of fluid through an impeller-type flow meter and comparing it with an actual flow rate, there is a problem that labor and cost are required as in the case of maintenance.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a self-diagnosis device for an impeller-type flow meter capable of reducing labor and cost due to maintenance.

The self-diagnosis device for an impeller-type flow meter according to the first aspect of the present invention, which has been made to achieve the above object, provides a fluid flow in the measurement channel based on the amount of rotation of the impeller provided in the measurement channel. beyond the self-diagnosis apparatus for an impeller type flow meter for measuring the flow rate, the rotation amount of between up to inertial rotation of the impeller stops the flow of fluid stops, deceleration characteristic value, a predetermined reference value It is characterized in that it is provided with a deterioration judging means for judging whether or not the deterioration of the flow rate measurement accuracy is within an allowable range depending on whether or not it is.

  According to a second aspect of the present invention, in the self-diagnosis device for the impeller-type flow meter according to the first aspect, a lap time measuring means for measuring the time required for one rotation of the impeller as the lap time, and the lap time are predetermined. Stop determination means for determining whether or not the impeller has stopped depending on whether or not the stop determination time exceeded, update storage means for updating and storing the latest lap time for a predetermined number of rotations, It has a feature in that it includes a deceleration characteristic calculation means for calculating a deceleration characteristic value from a circulation time for a fixed number of rotations when the impeller stops.

  According to a third aspect of the present invention, in the self-diagnosis device for an impeller-type flow meter according to the second aspect, the deceleration characteristic calculating means calculates a total sum of circulation times for a plurality of rotations as a deceleration characteristic value. Have.

  According to a fourth aspect of the present invention, in the self-diagnosis device for an impeller-type flow meter according to the second aspect, the deceleration characteristic calculating means calculates a difference between the revolution times for a plurality of rotations as a deceleration characteristic value. Have

  According to a fifth aspect of the present invention, in the self-diagnosis device for the impeller-type flow meter according to the first aspect, stop detecting means for detecting the stop of the impeller, and the rotational position of the impeller at a predetermined cycle are detected. A rotational position sensor that outputs rotational position data, a data update storage unit that updates and stores the latest plurality of rotational position data detected by the rotational position sensor, and a plurality of rotational positions when the impeller stops. It has a feature in that it has a deceleration characteristic calculating means for calculating a deceleration characteristic value from the data.

When the rotation resistance of the impeller is increased, the rotation amount until the inertia rotation of the impeller is stopped, the deceleration characteristic value changes. In the self-diagnosis device for the impeller-type flow meter of the present invention, it is determined whether or not the deterioration of the flow measurement accuracy is within an allowable range depending on whether or not the deceleration characteristic value until the inertial rotation of the impeller stops exceeds a reference value. As a result, it is possible to know the optimal maintenance time without the conventional labor and cost. As a result, it is possible to prevent excessive maintenance and reduce maintenance effort and costs.

  Here, when obtaining the deceleration characteristic value of the impeller, for example, a fluid stopping means for forcibly stopping the fluid flow is provided, and the impeller is rotated after the fluid flow is stopped. Based on this, the latest data relating to the rotation of the impeller is updated and stored so that the deceleration characteristic value may be calculated on the basis of this, and the fluid may stop at any time. The stoppage of the impeller may be automatically determined, and after the impeller has stopped, the deceleration characteristic value may be calculated based on the latest data relating to the rotation of the impeller before the stop.

The conceptual diagram of the impeller type flow meter provided with the self-diagnosis device of a 1st embodiment concerning the present invention. Cross section of impeller flow meter Conceptual diagram of an impeller-type flow meter provided with a self-diagnosis device according to a second embodiment

[First Embodiment]
A first embodiment of the present invention will be described below with reference to FIGS. The impeller flow meter 10 shown in FIG. 1 includes a flow meter main body 11 and a signal processing unit 20. As shown in FIG. 2, the flowmeter main body 11 includes an impeller 16 inside a cylindrical measurement tube 12 (corresponding to a “measurement flow path” of the present invention), for example. Further, flange portions 12F and 12F are provided at both ends of the measuring tube 12, and a plurality of mounting holes 12A are formed through each flange portion 12F. The measuring pipe 12 is arranged in the middle of the gas pipe 90 through which combustion gas as a fluid flows, and is fixed to the gas pipe 90 with a bolt (not shown) inserted through the mounting hole 12A of each flange portion 12F. .

  The impeller 16 includes a plurality of blades 16B on the outer peripheral surface of the blade support plate 16A, the rotation shaft 16C projects from the center of one end surface of the blade support plate 16A, and the rotation shaft 16C is rotatably supported by the rotation support member 13. Has been. The rotation support member 13 has a structure in which a plurality of rectifying plates 13F project radially from one end of the support column 13S, and the plurality of rectifying plates 13F are formed at the opening edge of one end of the measuring tube 12, for example. The gas pipe 90 is prevented from coming off in a state of being fitted in the locking groove 12B. Further, the rotation support member 13 is provided with a center hole 13C at an end opposite to the end provided with the rectifying plate 13F, and a pair of bearings 15 and 15 are provided in the center hole 13C, for example. Yes. As described above, the rotary shaft 16C is rotatably supported by the bearings 15 and 15. Further, the blade 16B has a twisted shape with respect to the rotational axis direction of the impeller 16, and receives dynamic pressure from the gas flowing in the measuring tube 12, whereby the impeller 16 rotates.

  A sensor support member 14 is provided on the opposite side of the measurement tube 12 from the rotation support member 13 with the blade support plate 16A interposed therebetween. Similar to the rotation support member 13, the sensor support member 14 has a structure in which a plurality of rectifying plates 14 </ b> F project radially from one end of the support column 14 </ b> S, and the plurality of rectifying plates 14 </ b> F are associated with the opening edge of the measuring tube 12. The gas pipe 90 is used to prevent it from coming off in a state where it is accommodated in the stop groove 12B.

  An origin detection magnet 17A is embedded in the end face of the blade support board 16A facing the sensor support member 14 at a position away from the center. On the other hand, on the surface of the sensor support member 14 facing the blade support plate 16A, the origin detection magnetic sensor 17B is located at a position where it can face the origin detection magnet 17A in the axial direction of the blade support plate 16A and the sensor support member 14. Buried. The origin detection magnetic sensor 17B has an electric resistance that changes in accordance with the positional relationship with the origin detection magnetic magnet 17A.

  As shown in FIG. 1, the signal processing unit 20 includes an origin detection pulse generation circuit 21 connected to the origin detection magnetic sensor 17B. Here, assuming that the rotation position of the impeller 16 when the origin detection magnet 17A and the origin detection magnetic sensor 17B are closest to each other is the origin position, for example, the origin detection pulse generation circuit 21 has the origin detection magnetism. Based on the change in the electrical resistance of the sensor 17B, an origin detection pulse is output every time the impeller 16 passes the origin position.

  The origin detection pulse is captured by the control unit 22 provided in the signal processing unit 20. The control unit 22 includes a microcomputer (hereinafter referred to as a microcomputer) including a CPU, a ROM, and a RAM (not shown). The microcomputer executes a predetermined program stored in the ROM, and the microcomputer is shown in a block diagram in FIG. Function as the flow rate calculation unit 23, overmetering correction unit 24, self-diagnosis device 25, and display control unit 26 shown in FIG.

  The flow rate calculation unit 23 counts, for example, the number of origin detection pulses (that is, the amount of rotation of the impeller 16) per unit time (for example, 1 second or 1 minute), and sets a predetermined flow rate calculation coefficient in the count result. Multiply and calculate the flow rate of fluid per unit time, and also calculate the cumulative flow rate. The fluid calculation coefficient is such that a certain amount of fluid measured by a flow meter different from the impeller flow meter 10 of the present embodiment is actually flowed to the impeller flow meter 10 of the present embodiment, and at that time The number of origin detection pulses output from the origin detection pulse generation circuit 21 is counted and predetermined based on the relationship between the flow rate and the number of origin detection pulses. The flow rate calculated by the flow rate calculation unit 23 and the accumulated flow rate are transferred to the display control unit 26 and displayed on the display unit 27 provided in the signal processing unit 20.

  The overmetering correction unit 24 determines whether or not the impeller 16 is inertially rotated with a rapid decrease in the flow rate of the fluid. If the impeller 16 is inertially rotated, the amount of inertial rotation is determined. Is corrected by subtracting the origin detection pulse number from the count value of the origin detection pulse by the flow rate calculation unit 23. This prevents over metering. The over metering means that the impeller-type flow meter 10 measures a flow rate higher than the actual flow rate due to the inertia rotation of the impeller 16 after the fluid flow rate suddenly decreases. Techniques for prevention are described in, for example, JP-A-1-282426, JP-A-3-107726, and JP-A-8-62017. The overmetering correction unit 24 of the impeller-type flow meter 10 according to the present embodiment determines whether the impeller 16 is rotating by inertia using the same technique as that disclosed in these publications. Processing is in progress.

  The self-diagnosis device 25 measures the output interval of the origin detection pulse from the origin detection pulse generation circuit 21, that is, the time required for one rotation of the impeller 16 as the revolution time according to the present invention. 28. Therefore, when the impeller 16 is continuously rotated and the origin detection pulse is sequentially generated, the lap time is sequentially measured by the lap time measuring unit 28 (corresponding to the “lap time measuring means” of the present invention). Go.

  The progress of the measurement of the lap time by the lap time measuring unit 28 is monitored by a process determining unit 29 (corresponding to “stop determining means” of the present invention). The processing determination unit 29 determines that the impeller 16 is in a stopped state when the circulation time exceeds a predetermined stop determination time during measurement. On the other hand, when the measurement of the lap time by the lap time measuring unit 28 is completed within the stop determination time, it is determined that the impeller 16 is in a rotating state. Then, when the process determination unit 29 determines that the impeller 16 is in a rotating state, the process determination unit 29 provides the data update unit 30 with data on the rotation time measured by the rotation time measurement unit 28. On the other hand, when it is determined that the impeller 16 has changed from the rotating state to the stopped state, the measurement of the lap time by the lap time measuring unit 28 is stopped, and the data update unit 30 is not provided with the lap time data, so that the deceleration characteristics are reduced. An activation command is given to the calculation unit 32 (corresponding to “deceleration characteristic calculation means” of the present invention).

  It should be noted that the lap time measuring unit 28 starts up on the condition that a new origin detection pulse is acquired from the origin detection pulse generation circuit 21 in a state where the measurement of the lap time is stopped, and measures the lap time again. Further, the process determination unit 29 monitors whether or not the impeller 16 continues to rotate continuously for a predetermined reference continuous rotation (for example, 1 billion rotations) or more, and exceeds the reference continuous rotation. When the impeller 16 is continuously rotated, a message is displayed on the process determination unit 29 through the display control unit 26 to “stop fluid flow for self-degradation diagnosis”.

  The data updating unit 30 stores (writes) the data of the lap time acquired from the lap time measuring unit 28 in a predetermined plurality of data storage units 31 set in advance in the memory space of the RAM of the microcomputer. Specifically, each data storage unit 31 is assigned an address. For example, the data update unit 30 stores data of the latest lap time in the data storage unit of the smallest address, and other than the smallest address. The data of the old lap time stored in each data storage unit 31 is sequentially moved to the data storage unit 31 of the next larger address, and further, the lap time of the lap time stored in the data storage unit 31 of the largest address is Discard the data. As a result, the latest fixed number of round times are updated and stored in the data storage unit 31. That is, the latest round time for a predetermined number of rotations determined in advance by the data updating unit 30 is updated and stored in the RAM. In the impeller flow meter 10 of the present embodiment, the above-described data update unit 30 and data storage unit 31 constitute the “update storage unit” according to the present invention.

  When the deceleration characteristic calculation unit 32 receives an activation command from the processing determination unit 29 due to the stop of the impeller 16, the sum of the rotation time data stored in all the data storage units 31 (that is, the rotation time for a certain number of rotations). Is calculated as a deceleration characteristic value according to the present invention, and is given to the deterioration determination unit 33 (corresponding to “deterioration determination means” of the present invention). Then, the deterioration determination unit 33 compares the impeller stop time with the first reference stop time set in advance and the second reference stop time that is smaller than the first reference stop time.

  When the impeller stop time is equal to or longer than the first reference stop time, the deterioration determination unit 33 displays a message indicating that the rotational resistance of the impeller 16 is within the allowable range (for example, “impeller rotation load is small: good The message “status” is displayed on the display unit 27 through the display control unit 26. In addition, when the impeller stop time is shorter than the first reference stop time and equal to or longer than the second reference time, the deterioration determination unit 33 sends a message that the rotational resistance of the impeller 16 exceeds the allowable range (for example, The message “High impeller rotational load: Need to maintain impeller and bearing” is displayed on the display unit 27, and if the impeller stop time is shorter than the second reference stop time, the impeller 16 rotates. A message to the effect that the resistance greatly exceeds the allowable range (for example, a message “Abnormal impeller rotational load: Immediate maintenance of impeller and bearing”) is displayed on display unit 27.

  The control unit 22 monitors the remaining capacity of the battery as a power source (not shown) provided in the signal processing unit 20, and displays a message to that effect when the remaining capacity falls below the reference value. This is displayed on the unit 27.

  This is the end of the description of the configuration of the impeller flow meter 10 having the self-diagnosis device 25 of the present embodiment. Next, the effect of this impeller type flow meter 10 is demonstrated. When the gas flows through the gas pipe 90 to which the impeller-type flow meter 10 is attached, the impeller 16 rotates, and each time the impeller 16 passes through the origin position, an origin detection pulse is generated and based on these origin detection pulses. The flow rate of the gas passing through the impeller flow meter 10 is measured.

By the way, for example, the flow rate of the gas flowing through the gas pipe 90 may suddenly decrease, as in the case of stopping after using the water heater in the house. Then, a phenomenon may occur in which the impeller 16 rotates inertially after the gas flow is stopped. On the other hand, in the impeller-type flow meter 10 of the present embodiment, since the process of canceling the origin detection pulse for the inertia rotation of the impeller 16 is performed, the flow rate measurement is highly accurate even if the gas flow rate changes frequently. It can be performed.

  When the impeller 16 rotates inertially, if the rotational resistance of the impeller 16 due to wear of the bearing 15 is relatively small, the rotational speed due to the inertial rotation of the impeller 16 gradually decreases. The time required for the constant plural rotations before the rotation stops is relatively long. On the other hand, if the rotational resistance of the impeller 16 due to wear of the bearing 15 is relatively large, the rotational speed due to the inertial rotation of the impeller 16 rapidly decreases and stops, so that the inertial rotation of the impeller 16 is constant before it stops. The time required for multiple rotations is relatively short.

  On the other hand, the self-diagnosis device 25 provided in the impeller-type flow meter 10 of the present embodiment updates and stores the latest revolution time for a plurality of rotations of the impeller 16 and stops the impeller 16. When the impeller 16 stops, whether or not the deterioration of the flow rate measurement accuracy of the impeller-type flow meter 10 is within an allowable range according to the total length of the circulation time for a predetermined number of rotations before the stop. Determine whether. Then, as a result of determining the deterioration of the flow rate measurement accuracy, the display unit 27 is referred to as “large impeller rotational load: impeller and bearing need maintenance” or “impeller rotational load abnormality: impeller and bearing are urgently maintained”. When the message is displayed, the measurement tube 12 is removed from the gas tube 90, and then the rotation support member 13 is taken out of the measurement tube 12 together with the impeller 16, and the rotation support member 13 and the impeller 16 are exchanged, or the rotation support is supported. Maintenance for exchanging the bearings 15 in the member 13 is performed. On the other hand, when the message “impeller rotational load is small: good state” is displayed on the display unit 27 as the determination result of the deterioration of the flow measurement accuracy, the bearing 15 and the like can be replaced without worrying about the deterioration of the flow measurement accuracy. Thus, it is possible to continue using the impeller-type flow meter 10 with peace of mind without performing time-consuming maintenance.

  As described above, according to the self-diagnosis device 25 provided in the impeller-type flow meter 10 of the present embodiment, it is possible to know the optimum maintenance time without taking the labor and cost as in the prior art. Thereby, it is possible to prevent excessive maintenance and reduce labor and cost due to maintenance.

  In addition, you may comprise the above-mentioned deceleration characteristic calculating part 32 and the degradation determination part 33 as follows. That is, when the deceleration characteristic calculation unit 32 receives an activation command from the process determination unit 29 due to the stop of the impeller 16, it calculates the difference between the lap times stored in the data storage unit 31 of the adjacent address, The difference of the maximum value is obtained from the difference between the round times of the set, and the deterioration determining unit 33 determines the maximum difference between the round times obtained by the deceleration characteristic calculation unit 32, the first reference differential time set in advance, and You may make it the structure compared with the 2nd reference | standard difference time which is a value larger than the 1st reference | standard difference time. And the deterioration determination part 33 displays the message "impeller rotation load small: good state" on the display part 27, for example, when the largest difference between circulation times is below 1st reference | standard difference time, When the maximum difference between the revolution times is greater than the first reference difference time and less than or equal to the second reference time, for example, a message “impeller rotation load is large: impeller and bearing need maintenance” is displayed on the display unit. 27, and when the maximum difference between the lap times is larger than the second reference difference time, for example, a message “impeller rotational load abnormality: impeller and bearing part is urgently maintained” is displayed on the display part 27. May be displayed.

  Note that when the inertial rotation of the impeller 16 stops, the rotation speed decreases as it approaches the stop, so the circulation time becomes longer. If the rotational resistance of the impeller 16 is relatively small, the rotational speed due to the inertial rotation of the impeller 16 gradually decreases, so that the difference between the revolution times is relatively small, while the rotational resistance of the impeller 16 is compared. When the target is large, the difference between the lap times is relatively large. Thereby, even if it utilizes the difference between the said lap times, deterioration of flow measurement accuracy can be self-diagnosed.

[Second Embodiment]
An impeller-type flow meter 10V of the present embodiment is shown in FIG. 3, and the impeller 16 included in the flow meter main body 11V replaces the origin detection magnet 17A and the origin detection magnetic sensor 17B in the first embodiment. The rotational position detection magnet 41A is embedded in the center of the blade support board 16A, and the rotational position detection magnetic sensor 41B is embedded in the sensor support member 14 at a position facing the rotational position detection magnet 41A. Further, the rotational position detecting magnetic sensor 41B is connected to the rotational position data generation circuit 40 provided in the signal processing unit 20V. The rotational position detection magnetic sensor 41B sets a predetermined division angle obtained by dividing one rotation of the impeller 16 into a plurality of divisions as a so-called electrical rotation, and the electric resistance changes according to the position within the division angle. It is configured. Then, the rotational position data generation circuit 40 generates rotational position data for specifying the rotational position of the impeller 16 based on the change in electrical resistance of the rotational position detection magnetic sensor 41B, and the impeller 16 determines the origin position. An origin detection pulse is output every time it passes. The rotational position detection required magnetic sensor 41B and the rotational position data generation circuit 40 correspond to the “rotational position sensor” of the present invention.

  The data update unit 30V included in the self-diagnosis device 25V of the present embodiment takes in the rotational position data generated by the rotational position data generation circuit 40 at a predetermined data acquisition cycle (for example, 10 to 50 [msec]), and first Similarly to the data update unit 30 of the embodiment, the data storage unit 31 is configured to update and store the latest fixed plurality of latest rotation position data. When the process determination unit 29 determines that the impeller 16 has changed from the rotation state to the stop state, the update storage of the rotation position data in the data storage unit 31 is stopped, and the deceleration characteristic calculation unit 32V is activated. Then, the deceleration characteristic calculation unit 32 calculates the maximum value of the deceleration (negative acceleration) of the impeller 16 based on the latest rotational position data group stored in the data storage unit 31 and the data acquisition cycle. To the deterioration determination unit 33V. Then, the deterioration determination unit 33V compares the maximum value of the deceleration of the impeller 16 with a preset reference deceleration. When the deceleration of the impeller 16 is equal to or less than the reference deceleration, for example, “impeller When the display unit 27 displays a message “low rotational load: good state” and the maximum deceleration value of the impeller 16 is larger than the reference deceleration, for example, “high impeller rotational load: maintenance of the impeller and the bearing unit”. The message “necessary” is displayed on the display unit 27. The configuration of this embodiment also has the same effect as that of the first embodiment.

  In the deceleration characteristic calculation unit 32 of the second embodiment, an approximate expression is created based on the latest rotational position data group stored in the data storage section 31 and the data acquisition cycle, and the blade is calculated from the approximate expression. The maximum value of deceleration (negative acceleration) of the vehicle 16 may be calculated.

  In the self-diagnosis device 25V of the second embodiment, only the rotational position data is captured without capturing the origin detection pulse output from the rotational position data generation circuit 40, and the rotational speed of the impeller 16 is always derived from the rotational position data. When the rotational speed of the impeller 16 coincides with “0” within a specified error range, the update of the rotational position data in the data storage unit 31 by the data update unit 30 is stopped, and the deceleration characteristic You may make it the structure which starts the calculating part 32V.

  Further, a rotation angle (hereinafter referred to as “stop rotation angle”) in which the impeller 16 is rotated within a predetermined time from the time when the rotation speed of the impeller 16 coincides with “0” within a specified error range is described in the present invention. If the stop rotation angle is smaller than a preset reference stop rotation angle, the fact that the flow rate measurement accuracy has deteriorated beyond the allowable range is displayed on the process determination unit 29. However, when the stop rotation angle is equal to or larger than the reference stop rotation angle, the processing determination unit 29 may display that the deterioration of the flow rate measurement accuracy is within the allowable range.

[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 and second embodiments, the gas is exemplified as the fluid. However, the present invention is not limited to the gas, and may be a liquid such as water, for example.

(2) In the first and second embodiments, the determination result of the deterioration in the measurement accuracy of the flow rate is always displayed on the display unit 27. For example, the determination result is stored and the unit time ( For example, the latest determination result may be displayed every hour or one day.

(3) In the first and second embodiments, the determination result of the deterioration of the measurement accuracy of the flow rate is displayed on the display unit 30 with a message such as “low impeller rotational load: good state”. A lamp may be provided in the unit, and the determination result may be indicated by lighting / flashing of the lamp, or the determination result may be indicated by a lamp color (for example, red / blue) or voice guidance.

10, 10V Impeller-type flow meter 11, 11V Flow meter body 12 Measuring tube 16 Impeller 20, 20V Signal processing unit 25, 25V Self-diagnosis device 28 Circulation time measurement unit (circulation measurement means)
29 Process determination unit (stop determination means, stop detection means)
30 Data storage unit (data update storage unit)
32 Deceleration specific calculation unit (deceleration characteristic calculation means)
33 Degradation determination unit (degradation determination means)

Claims (5)

In the self-diagnosis device of the impeller-type flow meter that measures the flow rate of the fluid flowing in the measurement passage based on the rotation amount of the impeller provided in the measurement passage,
Rotation of until the inertia rotation of the impeller stops the flow of the fluid is stopped, deceleration characteristic value, deterioration of the flow rate measuring accuracy depending on whether exceeds a predetermined reference value is within the permissible range A self-diagnosis device for an impeller-type flow meter, comprising a deterioration determining means for determining whether or not. Lap time measuring means for measuring the time required for one rotation of the impeller as a lap time;
Stop determination means for determining whether or not the impeller has stopped depending on whether or not the lap time has exceeded a predetermined stop determination time;
Update storage means for updating and storing the latest lap time for a predetermined number of predetermined rotations;
The impeller-type flow rate according to claim 1, further comprising deceleration characteristic calculation means for calculating the deceleration characteristic value from the rounding time for the predetermined number of rotations when the impeller stops. Total self-diagnosis device.   3. The self-diagnosis device for an impeller-type flow meter according to claim 2, wherein the deceleration characteristic calculation means calculates the total sum of the lap times for the plurality of rotations as the deceleration characteristic value.   3. The self-diagnosis device for an impeller-type flow meter according to claim 2, wherein the deceleration characteristic calculating means calculates a difference between the circulation times corresponding to the predetermined number of rotations as the deceleration characteristic value. Stop detection means for detecting the stop of the impeller;
A rotational position sensor for detecting rotational position of the impeller at a predetermined cycle and outputting rotational position data;
A data update storage unit for updating and storing the latest plurality of rotational position data detected by the rotational position sensor;
The impeller-type flow meter according to claim 1, further comprising deceleration characteristic calculation means for calculating the deceleration characteristic value from the predetermined plurality of rotational position data when the impeller stops. Self-diagnosis device.

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