JP3349604B2 - Gas meter flow compensator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate correction device for a gas meter for correcting an instrumental difference which differs depending on a flow rate.

[0002]

2. Description of the Related Art In general, in a gas meter, the instrumental differences are different when the flow rate (flow velocity) is different. Here, the instrumental difference means a difference between the indicated flow rate of the reference device and the indicated flow rate of each gas meter expressed as a percentage with respect to the indicated flow rate of each gas meter. Further, in the gas meter, a measurement error from the mechanism occurs depending on the amount of fluid passing during the test. Therefore, for the gas meter, the test is performed with the flow rate (verification flow rate) and the passing amount according to the maximum use flow rate or number indicated on the gas meter, and the gas meter is corrected so that the instrumental error falls within the verification tolerance. Defined by the Measurement Law.

FIG. 10 is a characteristic diagram showing a test tolerance. As shown by hatching in this figure, the verification tolerance is 2.5% for a flow rate that is 1/20 or more and less than 1/5 of the maximum flow rate,
For the flow rate of 1/5 or more and less than 4/5 of the maximum flow rate, 1.
5%, 2.5% for 4/5 or more of the maximum flow rate
It has become.

Therefore, conventionally, the instrumental difference is measured at two points of the maximum flow rate and the verification flow rate (about 30% of the maximum flow rate), and the number of gear teeth and the timing of rotation of the mechanical movable part which moves according to the flow rate are measured. The gas meter was manufactured by performing a mechanical correction such as changing the temperature.

[0005]

However, the above-described correction method requires a complicated mechanical correction process such as gear change for correcting the instrumental error on the production line, and the gas meter is required to perform such a process. In addition to the cost increase, there is a possibility that a defective product may be generated due to an incorrect operation.

As a method of measuring the flow rate in a gas meter having a mechanically movable part such as a membrane gas meter, for example, as shown in Japanese Patent Application Laid-Open No. Hei 5-107096, one cycle of the operation of the mechanically movable part is disclosed. Is provided, and a plurality of magnets provided on the disk and a magneto-resistive element provided near the disk are used during one cycle of the operation of the mechanically movable portion. To output multiple pulses,
There is a method of calculating the flow rate from the frequency and cycle of this pulse. In a gas meter that measures the flow rate in this manner, for example, as disclosed in Japanese Patent Application Laid-Open No. 58-34321, the cycle of the pulse is measured, and a correction process is performed for each cycle of the pulse. It is conceivable to calculate the flow rate.

[0007] However, in a membrane gas meter or the like, even when the flow rate is constant, the speed of the disk interlocking with the mechanically movable portion may change during one rotation for mechanical reasons. In such a case, since the pulse cycle changes even if the flow rate is constant, there is a problem that accurate correction cannot be performed even if the flow rate is corrected for each pulse cycle as described above. is there.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a gas meter having a mechanically movable portion that eliminates the need for complicated mechanical flow rate correction processing and reduces the flow rate when the flow rate is constant. It is an object of the present invention to provide a gas meter flow rate correction device that enables highly accurate flow rate correction processing even when the operation speed of a mechanically movable portion changes during one cycle.

[0009]

According to a first aspect of the present invention, there is provided a gas meter having a mechanically movable portion which performs a periodic operation at a speed corresponding to a flow rate. A pulse output means for outputting pulses at a plurality of positions during one cycle of the operation of the mechanically movable part, and an average of the cycle of the pulses output from the pulse output means at predetermined time intervals. Average pulse period calculating means for calculating an average pulse period as a value, and performing correction in accordance with the average pulse period calculated by the average pulse period calculating means, and calculating a corrected flow rate based on the average pulse period. And a correction flow rate calculating means.

In this gas meter flow correction device, the pulse output means outputs pulses at a plurality of positions in one cycle of the operation of the mechanically movable part, and the average pulse period, which is the average value of the pulse periods, is averaged. It is calculated by the pulse period calculation means. Then, the correction according to the average pulse period is performed by the correction flow rate calculating means,
A corrected flow rate is calculated.

According to a second aspect of the present invention, there is provided a gas meter having a mechanically movable portion which performs a periodic operation at a speed corresponding to a flow rate. A pulse output means for outputting a pulse at a plurality of positions during one cycle of the operation of the mechanical movable part; and a cycle of the pulse output from the pulse output means for one or more cycles of the operation of the mechanical movable part Average pulse period calculating means for calculating an average pulse period which is an average value of the average pulse period, and performing correction in accordance with the average pulse period calculated by the average pulse period calculating unit, and correcting the corrected flow rate based on the average pulse period. And a correction flow rate calculating means for calculating.

In this flowmeter for a gas meter, the pulse output means outputs pulses at a plurality of positions in one cycle of the operation of the mechanically movable part, and the average pulse period calculation means calculates the operation of the mechanically movable part. An average pulse cycle, which is an average value of the cycle of the pulse output from the pulse output means, is calculated for each one or a plurality of cycles. Then, a correction according to the average pulse period is performed by the corrected flow rate calculating means, and the corrected flow rate is calculated.

According to a third aspect of the present invention, there is provided a flow rate correcting device for a gas meter according to the first or second aspect, wherein the corrected flow rate calculating means corrects the average pulse cycle calculated by the average pulse cycle calculating means. The table has a table indicating the relationship with the flow rate, and the corrected flow rate is calculated based on the average pulse cycle calculated by the average pulse cycle calculation means with reference to the table.

According to a fourth aspect of the present invention, there is provided a gas meter flow rate correcting device according to the first or second aspect, wherein the corrected flow rate calculating means includes an average pulse cycle calculated by the average pulse cycle calculating means and an instrumental error. With reference to this table, an instrumental difference according to the average pulse cycle calculated by the average pulse cycle calculating means is obtained, and the instrumental difference and the instrumental difference calculated by the average pulse cycle calculating means are obtained. The corrected flow rate is calculated based on the average pulse period.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 5 relate to a first embodiment of the present invention.

FIG. 1 is a sectional view showing a schematic configuration of a film-type gas meter as a gas meter including the flow rate correction device of the present embodiment. As shown in the figure, the gas meter has a case main body 10, and a gas inlet 11 and a gas outlet 12 are provided on the upper part of the case main body 10. Further, inside the case body 10, a front weighing chamber 20 and a rear weighing chamber 3 are provided.
0 is provided.

A membrane 21 is provided in the front weighing chamber 20 at the center in the front-rear direction (the left side in the figure is the front side), and a membrane plate 22 is attached to the membrane 21. Here, a space on the front side of the membrane 21 in the front measurement chamber 20 is a room, and a space on the rear side is a room. A gas inlet / outlet 23 communicating with the chamber and a gas inlet / outlet 24 communicating with the chamber are provided at an upper portion of the front measuring chamber 20. A blade axis 26 is connected to the membrane plate 22 via a blade 25. Wing axis 2
Numeral 6 rotates with the movement of the film 21 in the front-rear direction. The blade shaft 26 penetrates through the front measurement chamber 20 and protrudes upward.

Similarly, a membrane 31 is provided in the rear measuring chamber 30 at the center in the front-rear direction.
Is attached. Here, the space in front of the membrane 31 in the rear measurement chamber 30 is defined as a room, and the space on the rear side is defined as a room. A gas inlet / outlet portion 33 communicating with the chamber and a gas inlet / outlet portion 34 communicating with the chamber are provided at an upper portion of the rear measuring chamber 30. Further, a blade shaft 36 is connected to the membrane plate 32 via a blade. The blade shaft 36 is configured to rotate with the movement of the membrane 31 in the front-rear direction. The blade shaft 36 penetrates through the rear measuring chamber 30 and protrudes upward.

A gas outlet pipe 13 is provided between the gas inlet / outlet sections 23 and 24 and between the gas inlet / outlet sections 33 and 34, respectively.
Are provided. The gas outlet pipe 13 is connected to the gas outlet 12. In addition, gas doorway 2
A valve 14 is provided above 3, 3. The valve 14 has a state in which the gas ports 23 and 24 are both closed, a state in which the gas ports 23 and the gas outlet pipe 13 are in communication, and a state in which the gas ports 24 and the gas outlet pipe 13 are in communication. You can choose. Similarly, a valve 15 is provided above the gas inlet / outlet portions 33 and 34.
Is provided. The valve 15 has a state in which the gas inlet / outlet portions 33 and 34 are both closed, a state in which the gas outlet / inlet portion 33 communicates with the gas outlet pipe 13, and a state in which the gas inlet / outlet portion 3 is closed.
4 and a state in which the gas outlet pipe 13 is in communication.

The upper end of the blade shaft 26 is connected to an elbow 27, and the upper end of the blade shaft 36 is connected to an elbow 37. These elbows 27 and 37 are connected to an adjustment plate 42 by pins 41. A crank arm 44 and valve arms 45 and 46 are connected to the adjustment plate 42 via a crank pin 43. The crank arm 44 is connected to a crankshaft 47, and rotates the crankshaft 47. Also, the valve arms 45, 4
Numerals 6 are connected to valves 14 and 15, respectively, so that the valves 14 and 15 are moved. A disk 51 (FIG. 3) described later is attached to the crankshaft 47 via a worm and a worm wheel (not shown).

Here, the outline of the operation of the gas meter shown in FIG. 1 will be described with reference to FIG. Weighing chamber 20,
The introduction of gas into 30 and the discharge of gas from metering chambers 20 and 30 are performed by the interlocking action of valves 14 and 15 and membranes 21 and 31. The driving force for the movement of the membranes 21 and 31 is the gas pressure difference between the gas inlet 11 and the gas outlet 12. In the state shown in FIG. 2A, the valve 14 closes both the gas ports 23 and 24, and the valve 15 connects the gas port 33 and the gas outlet pipe 13. In this state, the gas entering the chamber from the gas inlet / outlet section 34 pushes the membrane 31 in the direction of the chamber due to the pressure difference, and the gas in the chamber passes through the gas inlet / outlet section 33, the valve 15, and the outlet pipe 13 in order, and the gas outlet section It is discharged from 12. The movement of the membrane 31 is transmitted to the blade shaft 36, the elbow 37, the adjusting plate 42, and the valve arms 45 and 46 in this order, and as shown in FIG. 2B, the valve 14 is connected to the gas inlet / outlet 24 and the gas outlet pipe. 1
3 and at the same time, the valve 15 is moved to a state in which the gas inlet / outlet portions 33 and 34 are both closed. At this time, the gas in the room is supplied to the gas inlet / outlet portion 23 and the valve 1.
4. The gas is discharged from the gas outlet 12 through the outlet pipe 13 in order. Hereinafter, similarly, the movement of returning to the state of FIG. 2A through the states of FIGS. 2C and 2D is repeated. Further, with the above movement, the crank arm 44 and the crank shaft 47 rotate. The rotation of the crankshaft 47 rotates a disk 51 (FIG. 3) described later via a worm and a worm wheel (not shown).

FIG. 3 is a block diagram showing a circuit configuration of a gas meter including the flow rate correction device of the present embodiment. In this figure, reference numeral 51 indicates a disk connected to the crankshaft 47 as described above. The disk 51 makes one rotation corresponding to one cycle of the mechanical operation of the gas meter shown in FIG. A plurality of, for example, five magnets 52 are attached to the disk 51 at equal intervals along the circumferential direction. The gas meter includes a magnetoresistive element 53 that is provided near the disk 51 and detects a change in a magnetic field accompanying the approach and separation of the magnet 52 as a change in resistivity. The gas meter further includes an analog amplifier 54 for amplifying an output signal of the magnetoresistive element 53, a waveform shaping circuit 55 for shaping a waveform of the output signal of the analog amplifier 54 to generate a pulse, and an output from the waveform shaping circuit 55. A pulse counter 61 for measuring the number of pulses to be counted, a timer 62 for counting a predetermined time, and, when the timer 62 has counted a predetermined time, the number of pulses measured by the pulse counter 61 and a predetermined time for the timer 62 to count. And an average pulse period calculation unit 63 that calculates an average pulse period that is an average value of pulse periods in a predetermined time based on the average pulse period calculation unit 63 with reference to the correction table 65. Correction according to the cycle is performed, and the corrected flow rate and the integrated flow rate are calculated based on the average pulse cycle. Positive arithmetic unit 64, the correction calculating unit 57
And a display section 59 for displaying the integrated flow rate determined by the above. The pulse counter 61, the timer 62, the average pulse cycle calculator 63, the flow rate calculator 64, and the correction table 65 are realized by, for example, a microcomputer 60.

In this embodiment, the correction table 65 stores the relationship between the average pulse period calculated by the average pulse period calculator 63 and the corrected flow rate. here,
The relationship between the average pulse period calculated by the average pulse period calculation unit 63 and the corrected flow rate will be described with reference to FIG. Since the average pulse cycle calculated by the average pulse cycle calculation unit 63 corresponds to the gas flow rate, the gas flow rate can be obtained as “k / average pulse cycle”, where k is a predetermined coefficient. However, this gas flow rate is before correction including instrumental errors. FIG. 4 shows an example of the relationship between the flow rate before correction obtained from the average pulse period and the correct flow rate. This relationship can be obtained from the indicated flow rate of the gas meter before correction and the indicated flow rate of the reference device. As described above, since the flow rate before correction has a corresponding relationship with the average pulse cycle, the relationship between the average pulse cycle and the correct flow rate is obtained from the relationship shown in FIG. The correction table 65 stores the relationship between the average pulse cycle and the corrected flow rate (correct flow rate) obtained from the relation shown in FIG.

Next, the operation of the flow rate correction device of the present embodiment will be described with reference to the flowchart of FIG. The gas meter performs the motion shown in FIG. 2 at a speed corresponding to the gas flow rate, and with this motion, the disk 51 shown in FIG. 3 rotates at a speed corresponding to the gas flow rate. The magnet 5 provided on the disk 51
The output of the magneto-resistive element 53 changes with the approach and separation of 2, and the output signal of the magneto-resistive element 53 is amplified by the analog amplifier 54 and shaped by the waveform shaping circuit 55.
A pulse having a cycle corresponding to the flow rate is generated. As shown in FIG. 5, the flow rate correction device starts counting the number of pulses by the pulse counter 61 from the time when the first pulse is output from the waveform shaping circuit 55 (step S101), and simultaneously sets the predetermined time by the timer 62. Start timing. Then, it is determined whether or not a predetermined time has elapsed (step S).
102) If the predetermined time has not elapsed (N), the process returns to step S102 to continue measuring the number of pulses. When the predetermined time has elapsed (Y), a calculation command 71 is sent from the timer 62 to the average pulse period calculation unit 63, and in response to this, the average pulse period calculation unit 63
An average pulse period is calculated based on the number of pulses measured in step 1 and a predetermined time measured by the timer 62 (step S103). After the calculation command 71 is sent to the average pulse period calculator 63, a reset signal 72 is sent from the timer 62 to the pulse counter 61, and the pulse counter 61 is reset accordingly. Then, the pulse counter 61 starts counting the number of pulses again, and the timer 62 starts counting a predetermined time. Next, the flow rate calculating section 64 refers to the table 65 representing the relationship between the average pulse cycle calculated by the average pulse cycle calculating section 63 and the corrected flow rate, and refers to the average pulse cycle calculating section 63.
The corrected flow rate is calculated based on the average pulse cycle calculated by (Step S104). Then, the integrated flow rate obtained by integrating the corrected flow rates is displayed on the display unit 59.

As described above, according to the present embodiment, the corrected flow rate is calculated based on the average pulse cycle with reference to the correction table 65 representing the relationship between the average pulse cycle and the corrected flow rate. This eliminates the need for a complicated mechanical correction process such as gear change for correcting instrumental differences on the production line, which can reduce the cost of the gas meter and prevent improper operation due to erroneous operation. Since non-defective products can be prevented, the process management is simplified.

In this embodiment, since the flow rate is corrected with reference to the correction table 65, the flow rate can be easily adjusted regardless of the relationship between the flow rate before correction and the correct flow rate as shown in FIG. Can be corrected, and more accurate correction can be performed as compared with mechanical correction.

In this embodiment, since the flow rate is corrected and calculated using the average pulse period at a predetermined time instead of the period between individual pulses, the processing load on the microcomputer 60 is reduced. You. Further, by using the average pulse period, when there is a minute flow rate fluctuation, the minute fluctuation occurring in the calculated flow rate can be reduced.

In this embodiment, since the flow rate is corrected and calculated using the average pulse period in a predetermined time, the flow rate is constant, but the flow rate is constant. Even when the pulse period changes, the flow rate can be corrected with high accuracy.

FIGS. 6 and 7 relate to a second embodiment of the present invention. In the present embodiment, the flow rate calculation unit 64 refers to the correction table 65 in FIG. 3 as a table representing the relationship between the average pulse cycle calculated by the average pulse cycle calculation unit 63 and the instrumental error. An instrumental difference corresponding to the average pulse cycle calculated by the average pulse cycle calculator 64 is obtained, and a corrected flow rate is calculated based on the instrumental error and the average pulse cycle calculated by the average pulse cycle calculator 63. It is like that.

Here, the relationship between the average pulse period calculated by the average pulse period calculation section 63 and the instrumental error will be described with reference to FIG. FIG. 6 shows an example of the relationship between the flow rate before correction obtained from the average pulse cycle calculated by the average pulse cycle calculator 63 and the instrumental error.
This relationship can be obtained from the indicated flow rate of the gas meter before correction and the indicated flow rate of the reference device. As described above, since the flow rate before correction has a correspondence with the average pulse cycle,
From the relationship shown in FIG. 6, the relationship between the average pulse period and the instrumental error is obtained. The correction table 65 in the present embodiment includes:
The relationship between the average pulse period and the instrumental difference obtained from the relationship shown in FIG. 6 is stored.

In this embodiment, as shown in the flow chart of FIG. 7, the pulse counter 61 starts counting the number of pulses from the time when the first pulse is output from the waveform shaping circuit 55 (step S201), and the timer starts counting. At 62, the counting of a predetermined time is started. Then, it is determined whether or not the predetermined time has elapsed (step S202). If the predetermined time has not elapsed (N), the process returns to step S202 to continue measuring the number of pulses. When the predetermined time has elapsed (Y), the average pulse period calculation unit 63 calculates the number of pulses measured by the pulse counter 61 and the timer 6
An average pulse period is calculated based on the predetermined time measured by 2 (step S203). Next, the average pulse cycle calculated by the average pulse cycle calculator 63 is referred to by the flow rate calculator 64 with reference to a table 65 representing the relationship between the average pulse cycle calculated by the average pulse cycle calculator 63 and the instrumental error. (Step S)
204). Then, the corrected flow rate is calculated based on the average pulse cycle and the instrumental difference calculated by the average pulse cycle calculation unit 63 (step S205). Here, assuming that the average pulse period calculated by the average pulse period calculation unit 63 is T and the instrumental difference calculated with reference to the table 65 is E, the corrected flow rate Y is calculated by the following equation. However,
k is a predetermined coefficient.

[0032]

Y = (k / T) · (1-E / 100)

Other configurations, operations and effects are the same as those of the first embodiment.

FIG. 8 is a block diagram showing a circuit configuration of a gas meter including a flow rate correction device according to a third embodiment of the present invention. In this embodiment, the pulse counter 61 shown in FIG.
For one cycle of the mechanical operation of the gas meter, ie, 5
The number of pulses is measured, and the timer 62 measures the time until the pulse counter 61 measures five pulses. The pulse counter 61 sends a calculation command 73 to the average pulse period calculation unit 63 and a reset signal 74 to the timer 62 every time five pulses are measured. The average pulse period calculation unit 63
In response to the operation instruction 73, the average pulse period is calculated based on the number of pulses measured by the pulse counter 61 and the time measured by the timer 62.

Other configurations and operations are the first or second.
This is the same as the embodiment of the present invention.

According to this embodiment, the average pulse period is calculated for each mechanical operation period of the gas meter, and the flow rate is corrected and calculated using the average pulse period. Even if the pulse period changes during one operation cycle due to mechanical reasons despite the fact that it is constant, the effect does not appear on the average pulse period, and compared with the case where the average pulse period is obtained at an arbitrary time interval. Thus, the flow rate can be corrected more accurately. Other effects are similar to those of the first embodiment.

The present invention is not limited to the above embodiments. For example, in the third embodiment, the average pulse period may be calculated for each of a plurality of mechanical operation periods of the gas meter.

The method of correcting the flow rate is not limited to the method using a table. For example, a mathematical expression expressing the corrected flow rate and the instrumental error as a function of the average pulse period is stored, and this mathematical expression is used. The flow rate and the instrumental error corrected from the average pulse cycle may be calculated.

Instead of the magnet 52 and the magnetoresistive element 53, a magnet attached to a movable part of the gas meter and a reed switch that opens and closes depending on the approach and separation of the magnet may be used. An encoder or the like may be used.

The flow rate correcting device for a gas meter according to the present invention is not limited to a film type gas meter, but can be applied to other types of gas meters having mechanically movable parts.

[0041]

As described above, according to the flow rate correcting device for a gas meter according to the first aspect and the third or fourth aspect cited in the first aspect, mechanical means is used for calculating the average pulse period. The average pulse period, which is the average value of the periods of the pulses output at a plurality of positions in one period of the operation of the movable portion, is calculated, and the correction is performed by the correction flow rate calculating means according to the average pulse period. In the gas meter having a mechanically movable portion, complicated mechanical flow rate correction processing is not required, and the operation speed of the mechanically movable portion is reduced during one cycle when the flow rate is constant. Therefore, even if the flow rate changes, the flow rate correction processing with high accuracy can be performed.

According to the second aspect of the present invention, the operation of the mechanical movable part is controlled by the average pulse period calculating means. Since the average pulse period is calculated every one or a plurality of periods, in addition to the above-described effect, the flow rate can be corrected more accurately than when the average pulse period is calculated at an arbitrary time interval. There is.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a gas meter including a flow rate correction device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an outline of an operation of the gas meter shown in FIG.

FIG. 3 is a block diagram illustrating a circuit configuration of a gas meter including the flow rate correction device according to the first embodiment of the present invention.

FIG. 4 is a characteristic diagram showing an example of a relationship between a flow rate before correction and a correct flow rate.

FIG. 5 is a flowchart showing the operation of the flow rate correction device according to the first embodiment of the present invention.

FIG. 6 is a characteristic diagram illustrating an example of a relationship between a flow rate before correction and an instrumental error.

FIG. 7 is a flowchart showing an operation of the flow rate correction device according to the second embodiment of the present invention.

FIG. 8 is a block diagram showing a circuit configuration of a gas meter including a flow rate correction device according to a third embodiment of the present invention.

FIG. 9 is a flowchart showing an operation of the flow rate correction device according to the third embodiment of the present invention.

FIG. 10 is a characteristic diagram showing a test tolerance.

[Explanation of symbols]

 51 Disk 52 Magnet 53 Magnetoresistive Element 55 Waveform Shaping Circuit 61 Pulse Counter 62 Timer 63 Average Pulse Period Calculator 64 Flow Calculator 65 Correction Table

Continued on the front page (73) Patent holder 000116633 Aichi Watch Electric Co., Ltd. 1-70 2-chome, Atsuta-ku, Nagoya-shi, Aichi (72) Inventor Tsutomu Otani 6-7-9 Yurinokidai, Yachiyo-shi, Chiba (72) Invention Author Takashi Ueki 1-11-3 Minamigahara, Ota-ku, Tokyo (72) Inventor Nobuo Negoro 1704-2, Izumi-cho, Izumi-ku, Yokohama-shi, Kanagawa-ken (72) Inventor Isao Kaneko 3-2-7-221 Takasago, Katsushika-ku, Tokyo (72) Inventor Kazuya Fujisawa 2-3-3-305 Nukii, Nerima-ku, Tokyo (72) Inventor Yoshio Yumida 226-1, Karaashi, Ageo-shi, Saitama (72) Inventor Yasuyoshi Sato 4, Tokumaru 4, Itabashi-ku, Tokyo −26−17−305 (72) Inventor Kazuo Shimakawa 2-5-7, Honmachi Nishi, Yono City, Saitama Prefecture (72) Inventor Mineyuki 3-15-7 Asahimachi, Funabashi City, Chiba Prefecture (72) Inventor Kaoru Maeda Chiba (72) Inventor Noriyuki Watanabe 1-2-70 Chitose, Atsuta-ku, Nagoya-shi, Aichi Prefecture Aichi Watch Electric Co., Ltd. (72) Inventor Katsu Hanaki Hisashi, Aichi Prefecture, Nagoya, Atsuta-ku 1-2-70, Aichi Watch Electric Co., Ltd. (56) References JP-A-6-42993 (JP, A) JP-A-4-265825 (JP, A) JP-A-58 −34321 (JP, A) JP 4-27489 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01F 1/00-9/02 G01F 25/00

Claims (4)

(57) [Claims] 1. A gas meter having a mechanically movable portion that performs a periodic operation at a speed corresponding to a flow rate, wherein the flow rate correction device of the gas meter for correcting a measured flow rate, wherein the operation of the mechanically movable portion is performed. Pulse output means for outputting pulses at a plurality of positions in one cycle; average pulse cycle calculation means for calculating, at predetermined time intervals, an average pulse cycle which is an average value of the cycle of the pulses output from the pulse output means And a corrected flow rate calculating means for performing correction according to the average pulse cycle calculated by the average pulse cycle calculating means and calculating a corrected flow rate based on the average pulse cycle. Gas meter flow correction device. 2. A gas meter having a mechanically movable portion that performs a periodic operation at a speed corresponding to a flow rate, wherein the flow rate correction device of the gas meter corrects a measured flow rate. Pulse output means for outputting a pulse at a plurality of positions in one cycle, and an average pulse which is an average value of a cycle of the pulse output from the pulse output means for every one or a plurality of cycles of the operation of the mechanically movable part. Mean pulse period calculating means for calculating a cycle, and correction flow rate calculating means for performing a correction according to the average pulse cycle calculated by the average pulse cycle calculating means, and calculating a corrected flow rate based on the average pulse cycle. And a flow rate correcting device for a gas meter. 3. The corrected flow rate calculating means has a table representing a relationship between the average pulse cycle calculated by the average pulse cycle calculating means and the corrected flow rate, and refers to the table to determine the average pulse rate. 3. The flow rate correction device for a gas meter according to claim 1, wherein the corrected flow rate is calculated based on the average pulse cycle calculated by the cycle calculation means. 4. The correction flow rate calculating means has a table representing a relationship between an average pulse cycle calculated by the average pulse cycle calculating means and an instrumental error. Calculating an instrumental difference corresponding to the average pulse cycle calculated by the means, and calculating a corrected flow rate based on the instrumental error and the average pulse cycle calculated by the average pulse cycle calculating means. The flow rate correction device for a gas meter according to claim 1.