JP3349603B2 - 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. 8 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 of 1/20 to less than 1/5 of the maximum flow rate, and 1.% for a flow rate of 1/5 to less than 4/5 of the maximum flow rate. 5
%, And 2.5% for a flow rate of 4/5 or more of the maximum flow rate.

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 the gas meter that measures the flow rate in this manner, the cycle of the pulse is measured, and for each cycle of the pulse,
It is conceivable to calculate a correction coefficient corresponding to the flow rate and calculate a corrected flow rate for each pulse cycle using the correction coefficient.

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, even if the flow rate is constant, the pulse period changes, so that an appropriate correction coefficient corresponding to the flow rate cannot be obtained. Therefore, even if the flow rate is corrected for each pulse period as described above, there is a problem that the correction cannot be performed with high accuracy.

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. An operation cycle measuring means for measuring the time of one or more cycles of the operation of the mechanical movable portion, and a correction for calculating flow rate correction information according to the time measured by the operation cycle measuring means. Information calculation means, pulse output means for outputting pulses at a plurality of positions in one cycle of the operation of the mechanical movable section, pulse cycle measurement means for measuring the cycle of pulses output from the pulse output means, The corrected flow rate is calculated based on the pulse cycle measured by the pulse cycle measuring means and the flow rate correction information calculated by the correction information calculating means. Is obtained by a that the correction flow rate calculating means.

[0010] In this flow rate correction device for a gas meter, the operation period measuring means measures the time of one or more cycles of the operation of the mechanical movable part, and the flow rate correction information according to this time is calculated by the correction information calculating means. You. Further, the pulse output means outputs pulses at a plurality of positions in one cycle of the operation of the mechanical movable section, and the cycle of the pulses is measured by the pulse cycle measuring means.
The corrected flow rate is calculated by the corrected flow rate calculating means based on the pulse cycle measured by the pulse cycle measuring means and the flow rate correction information calculated by the correction information calculating means.

According to a second aspect of the present invention, there is provided a gas flow correcting device for a gas meter according to the first aspect, wherein the correction information calculating means includes one or more periods of the operation of the mechanical movable part and the flow correction information. And a flow rate correction information is calculated with reference to this table.

According to a third aspect of the present invention, there is provided a gas meter flow rate correcting apparatus according to the first or second aspect, wherein the flow rate correction information is an instrumental error.

[0013]

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.

In the front weighing chamber 20, a membrane 21 is provided 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.

An upper end of the blade shaft 26 is connected to an elbow 27, and an 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. One magnet 52 is attached to the disk 51 in the vicinity of the outer peripheral portion, and a plurality of, for example, five magnets 53 are attached to the inner side of the magnet 52 at equal intervals along the circumferential direction. Have been. The gas meter further includes a magnetoresistive element 54 provided at a position capable of facing the magnet 52 and a magnetoresistive element 55 provided at a position capable of facing the magnet 53. These magnetoresistive elements 54 and 55 detect a change in the magnetic field accompanying the approach and separation of the magnets 52 and 53 as a change in resistivity. The gas meter further includes an analog amplifier 56 for amplifying an output signal of the magnetoresistive element 54, a waveform shaping circuit 57 for shaping the waveform of the output signal of the analog amplifier 56 to generate a pulse, and an output signal of the magnetoresistive element 55. An analog amplifier 58 for amplification and a waveform shaping circuit 59 for shaping a waveform of an output signal of the analog amplifier 58 to generate a pulse are provided.

The gas meter further includes an operation cycle measuring unit 61 which measures the cycle of the pulse output from the waveform shaping circuit 57 to measure the time of one cycle of the operation of the gas meter (hereinafter referred to as an operation cycle). A correction table 62 storing a relationship between an operation cycle and a correction coefficient;
, A correction coefficient calculation unit 63 that calculates a correction coefficient as flow rate correction information according to the operation cycle, a pulse cycle measurement unit 64 that measures the cycle of the pulse output from the waveform shaping circuit 59, A flow rate calculating section 65 for calculating a corrected flow rate and an integrated flow rate based on the pulse cycle measured by the cycle measuring section 64 and the correction coefficient calculated by the correction coefficient calculating section 63;
And a display unit 66 for displaying the integrated flow rate obtained by the step 5. Operation cycle measuring unit 61, correction table 6
2. The correction coefficient calculation unit 63, the pulse cycle measurement unit 64, and the flow rate calculation unit 65 are realized by, for example, the microcomputer 60.

Here, the relationship between the operation cycle and the correction coefficient will be described with reference to FIG. FIG. 4 shows an example of the relationship between the flow rate before correction 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. Since the pulse cycle measured by the pulse cycle measuring unit 64 corresponds to the gas flow rate, the gas flow rate can be obtained as “k / pulse cycle”, where k is a correction coefficient. However, from the relationship shown in FIG. 4, it is necessary to change the correction coefficient k according to the gas flow rate in order to obtain the correct flow rate. On the other hand, since the operation cycle measured by the operation cycle measuring unit 61 also corresponds to the gas flow rate, from the relationship shown in FIG. 4, the correct flow rate can be determined according to the operation cycle (in other words, according to the gas flow rate before correction). The correction coefficient k to be obtained can be determined. The relationship between the operation cycle and the correction coefficient k thus obtained from the relationship shown in FIG. 4 is stored in the correction table 62.

Next, the operation of the flow rate correction device of the present embodiment will be described with reference to the flow charts of FIGS.
The gas meter performs the operation shown in FIG. 2 at a speed corresponding to the gas flow rate.
The disk 51 shown in FIG. Then, as the magnet 52 provided on the disk 51 approaches and separates, the magnetoresistive element 54
The output signal of the magnetoresistive element 54 is amplified by an analog amplifier 56, and the waveform is shaped by a waveform shaping circuit 57. The output signal of the magnetoresistive element 54 is changed for each rotation of the disk 51, that is, for each cycle of the gas meter operation. A pulse (hereinafter, referred to as an operation cycle pulse) is generated. On the other hand, 5 provided on the disc 51
As the two magnets 53 approach and separate, the output of the magnetoresistive element 55 changes, and the output signal of the magnetoresistive element 55 is amplified by the analog amplifier 58, and the waveform is shaped by the waveform shaping circuit 59 to correspond to the flow rate. A periodic pulse is generated.

FIG. 5 is a flowchart showing the operation of calculating the correction coefficient in the flow rate correction device. In this operation, the flow rate correction device first determines whether an operation cycle pulse has been input to the operation cycle measurement unit 61 (step S10).
1). If no operation cycle pulse is input (N),
Move to another process (return). If the operation cycle pulse has been input (Y), it is determined whether or not it is the first operation cycle pulse (step S102). In the case of the first operation cycle pulse (Y), the operation cycle measurement unit 61 starts measuring the operation cycle (step S103), and shifts to another process. If it is not the first operation cycle pulse (N), the operation cycle measuring unit 61 measures the operation cycle which is the time from the previous operation cycle pulse input to the current operation cycle pulse input (step S104). Next, from this operation cycle, the correction coefficient k is calculated by the correction coefficient calculation unit 63 with reference to the correction table 62 (step S105). Then, the correction coefficient k output to the flow rate calculator 65 is updated (step S106), and the process proceeds to another process. Since the correction coefficient according to the operation cycle is not calculated until the operation cycle pulse is input twice, the correction coefficient calculation unit 63 transmits a predetermined initial value to the flow rate calculation unit 65 as the correction coefficient until then. Output.

FIG. 6 is a flowchart showing the operation of calculating the flow rate corrected by the flow rate correction device. In this operation, the flow rate correction device uses the pulse period measurement unit 64 to
The cycle of the pulse output from the waveform shaping circuit 59 is measured (step S201). Next, the flow rate calculation unit 65 calculates the pulse cycle measured by the pulse cycle measurement unit 64 and the correction coefficient calculation unit 63. The corrected flow rate is calculated based on the correction coefficient k (step S20).
2). Then, the integrated flow rate obtained by integrating the corrected flow rates is displayed on the display unit 66.

As described above, according to the present embodiment, an operation cycle, which is one cycle of the mechanical operation of the gas meter, is measured, a correction coefficient corresponding to the operation cycle is calculated, and the operation of the gas meter is measured. The cycle of the pulse output at a plurality of positions in one cycle of the above is measured, and the corrected flow rate is calculated based on the cycle of the pulse and the correction coefficient. This eliminates the need for a complicated mechanical correction process such as gear replacement to correct the gas flow, thereby reducing the cost of the gas meter and preventing the occurrence of defective products due to erroneous operations. Becomes easier.

Further, in this embodiment, the operation cycle is measured for each cycle of the operation of the gas meter, and a correction coefficient corresponding to the operation cycle is calculated. Is used to calculate the corrected flow rate for each pulse cycle. Therefore, even when the pulse period changes during one operation cycle due to mechanical reasons despite the fact that the flow rate is constant, it is possible to calculate an appropriate correction coefficient according to the flow rate. The flow rate can be accurately corrected without changing the correction coefficient.

In this embodiment, since the correction coefficient is calculated with reference to the correction table 62, the relationship between the flow rate before correction and the correct flow rate as shown in FIG. The flow rate can be corrected, and more accurate correction can be performed as compared with mechanical correction.

Next, a second embodiment of the present invention will be described. In this embodiment, an instrumental error is used as a correction coefficient. Therefore, in the present embodiment, the correction table 62 in FIG. 3 stores the relationship between the operation cycle measured by the operation cycle measurement unit 61 and the instrumental error.

Here, the relationship between the operation cycle and the instrumental error will be described with reference to FIG. FIG. 7 shows an example of the relationship between the flow rate before correction 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 operation cycle corresponds to the gas flow rate, the instrumental error can be determined according to the operation cycle from the relationship shown in FIG. In the correction table 62, the relationship between the operation cycle and the instrument error determined from the relationship shown in FIG. 7 is stored.

The correction coefficient calculating section 63 includes a correction table 62
, An instrumental difference corresponding to the operation cycle measured by the operation cycle measurement unit 61 is calculated and output to the flow rate calculation unit 65. The flow calculator 65 calculates a corrected flow based on the pulse cycle measured by the pulse cycle measuring unit 64 and the instrumental error. If the cycle measured by the pulse cycle measuring unit 64 is T and the instrumental difference calculated by the correction coefficient calculating unit 63 is E, the corrected flow rate Y is calculated by the following equation. Here, k ₀ is a predetermined coefficient.

[0032]

## EQU1 ## Y = (k ₀ / T) · (1−E / 100)

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

The present invention is not limited to the above embodiments. For example, in each embodiment, the correction coefficient (including the instrumental error) is obtained from the time of one cycle (operation cycle) of the operation of the gas meter. Alternatively, the time of a plurality of cycles of the operation may be measured, and the correction coefficient may be obtained from this time.

The method of calculating the correction coefficient is not limited to the method using a table. For example, an equation expressing the correction coefficient as a function of the operation cycle is stored, and the correction coefficient is calculated from the operation cycle using this equation. May be calculated.

The magnets 52 and 53 and the magnetoresistive element 5
Instead of 4 and 55, a magnet attached to the movable part of the gas meter and a reed switch that opens and closes according to the approach and separation of the magnet may be used, or an optical rotary 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.

[0038]

As described above, according to the flow rate correcting device for a gas meter of the present invention, the operation cycle measuring means can
The time of one or more cycles of the operation of the mechanically movable part is measured, the flow rate correction information according to this time is calculated by the correction information calculating means, and at a plurality of positions in one cycle of the operation of the mechanically movable part. The cycle of the output pulse is measured by the pulse cycle measuring means, and the correction flow rate calculating means corrects the pulse based on the pulse cycle measured by the pulse cycle measuring means and the flow rate correction information calculated by the correction information calculating means. Since the calculated flow rate is calculated, complicated mechanical flow rate correction processing becomes unnecessary, and even when the operation speed of the mechanical movable unit changes during one cycle when the flow rate is constant. Thus, there is an effect that highly accurate flow rate correction processing can be performed.

[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 an operation of calculating a correction coefficient in the flow rate correction device according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing an operation of calculating a corrected flow rate in the flow rate correction device according to the first embodiment of the present invention.

FIG. 7 is a characteristic diagram illustrating an example of a relationship between a flow rate before correction and an instrumental error.

FIG. 8 is a characteristic diagram showing a test tolerance.

[Explanation of symbols]

 51 Disc 52, 53 Magnet 54, 55 Magnetoresistive element 57, 59 Waveform shaping circuit 61 Operating cycle measuring section 62 Correction table 63 Correction coefficient calculating section 64 Pulse cycle measuring section 65 Flow rate calculating section

──────────────────────────────────────────────────続 き Continuing from the front page (73) Patentee 000116633 Aichi Watch Electric Co., Ltd. 1-270, Chitose, Atsuta-ku, Nagoya-shi, Aichi (72) Inventor Tsutomu Otani 6-7-9 Yurinokidai, Yachiyo-shi, Chiba ( 72) Inventor Takashi Ueki 1-11-3 Minakugahara, Ota-ku, Tokyo (72) Nobuo Negoro 1704-2, Izumi-cho, Izumi-ku, Yokohama, Kanagawa Prefecture 7-221 (72) Inventor Kazuya Fujisawa 2-5-3-305 Nukii, Nerima-ku, Tokyo (72) Inventor Yoshio Yumida 226-1, Kadashi, Ageo-shi, Saitama (72) Inventor Yasuyoshi Sato Itabashi, Tokyo 4-26-17-305, Tokumaru-ku (72) Inventor Kazuo Shimakawa 2-5-7, Honcho Nishi, Yono-shi, Saitama Prefecture (72) Inventor Mineyuki 3-15-7, Asahi-cho, Funabashi-shi, Chiba Prefecture (72) Kaoru Maeda Michino, Kamagaya City, Chiba Prefecture 2-8-16 Chuo (72) Inventor Noriyuki Watanabe 1-2-70 Chitose, Atsuta-ku, Nagoya, Aichi Prefecture Inside (72) Katsuhisa Hanaki 1-2-70 Chitose, Atsuta-ku, Nagoya, Aichi (56) References JP-A-6-42993 (JP, A) JP-A-58-34321 (JP, A) JP-A-4-265825 (JP, A) JP-A-4-27489 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01F 1/00-9/02 G01F 25/00

Claims (3)

(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. Operating cycle measuring means for measuring one or a plurality of cycles of time; correction information calculating means for calculating flow rate correction information according to the time measured by the operating cycle measuring means; one cycle of the operation of the mechanically movable part Pulse output means for outputting a pulse at a plurality of positions in the apparatus; pulse cycle measurement means for measuring the cycle of the pulse output from the pulse output means; pulse cycle and correction information measured by the pulse cycle measurement means Correction flow rate calculating means for calculating a corrected flow rate based on the flow rate correction information calculated by the calculating means. Gas meter of the flow rate correction device. 2. The apparatus according to claim 1, wherein the correction information calculating means has a table indicating a relationship between time of one or more cycles of the operation of the mechanical movable section and the flow rate correction information, and refers to the table to calculate the flow rate correction information. The flow rate correction device for a gas meter according to claim 1, wherein the flow rate is calculated. 3. The flow rate correction device for a gas meter according to claim 1, wherein the correction correction information is an instrumental error.