JP3203782B2 - Flow measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention monitors a flow rate of a gas or the like which is built in a gas meter or the like, estimates the type of gas equipment currently being used by changing the flow rate, and uses the gas equipment in an abnormal manner. The present invention relates to a flow rate measuring device built in a gas meter called a so-called microcomputer meter, which shuts off gas when it is determined that the gas flow is performed.

[0002]

2. Description of the Related Art An example in which a conventional flow rate measuring device is used in a membrane gas meter will be described with reference to FIG. In FIG. 2, 1 is a disk that makes one rotation in conjunction with one reciprocation of the membrane of the membrane gas meter, 2 is a plurality of magnets arranged at equal intervals on the outer periphery of the disk 1, and 3 is near the disk 1 It comprises only pulse generating means 4 which is fixedly arranged and comprises a magnetoresistive element for detecting a change in a magnetic field and outputting a pulse signal. The conventional gas meter monitors the flow rate and the integration processing means 5 for integrating a constant flow rate for each output signal of the flow rate measuring device including the pulse generation means 4, and when it is determined that there is danger in the gas usage state, the gas is measured. It comprises safety processing means 6 for shutting off.

[0003]

However, in the above-mentioned conventional configuration, the disk 1 does not rotate at a constant angular velocity even when a constant flow rate is applied as a characteristic of the film-type gas meter. There is a problem that the pulse output from the pulse generating means 4 does not become a pulse output at an equal interval even if 2 is arranged. If pulses at equal intervals are output, for example, if the volume of the membrane of the gas meter is 0.8 liter and the number of magnets 2 is 8, 0.8 round trips per membrane
One liter of gas flows, and eight pulses are output from the pulse generation means 4. This means that 0.1 liter flows per pulse. However, the fact that the output pulses of the pulse generating means 4 are not at equal intervals when a constant flow rate is applied indicates that the flow rates per pulse are different. That is, one pulse is 0.13 liter and another pulse is 0.07 liter. The total of eight pulses is 0.8 liter. Therefore, in the gas meter using such a conventional flow rate measuring device, the integration is not accurately performed every 0.1 liter, and the integrated display cannot be accurately displayed in the unit of 0.1 liter.

Further, it is impossible to measure an instantaneous flow rate of a small flow rate of about 0.1 liter / second (= 360 liter / hour) in a time of about 1 second, and a safety processing means for monitoring a gas use state. There was also a limit to improving the function of No. 6.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its first object to automatically correct the flow rate of each pulse from a pulse generation means to realize accurate and high-resolution flow rate measurement. It is.

A second object is to calculate an instantaneous flow rate per unit time and improve a safety function for monitoring a gas use state.

[0007]

In order to achieve the first object, a flow rate measuring device according to the present invention is linked to a mechanical movable part which makes one rotation or one reciprocation every time a certain volume of fluid flows. Pulse generating means for outputting a plurality of pulses by
A period measuring unit that measures a pulse period output by the pulse generating unit; a period storing unit that stores a pulse period output by the period measuring unit for a preset number of pulses; and a pulse period that is stored by the period storing unit. Period adding means for calculating a total value, determining means for determining whether the fluid is flowing at a constant flow rate from the total value of the pulse periods calculated by the periodic adding means, and the determining means for determining whether the fluid flows at a constant flow rate And a correction coefficient calculating means for calculating a pulse correction coefficient for calculating a flow rate corresponding to the pulse cycle stored in the cycle storing means when it is determined that the cycle is stored. In order to achieve the second object, the apparatus further comprises an instantaneous flow rate calculating means for calculating an instantaneous flow rate per unit time from the pulse cycle information stored in the cycle storing means and the correction coefficient calculated by the correction coefficient calculating means. is there.

[0008]

According to the present invention, the flow rate per each pulse signal output from the pulse generating means is automatically corrected by the above configuration, and accurate and high-resolution flow rate measurement can be realized. The instantaneous flow rate calculating means calculates the instantaneous flow rate for two unit times using the flow rate for each pulse calculated by the correction coefficient calculating means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The same parts as those in the conventional example are denoted by the same reference numerals. In FIG. 1, reference numeral 1 denotes a disk which makes one rotation in conjunction with one reciprocation of the membrane of the membrane gas meter, 2 denotes eight magnets arranged at equal intervals on the outer periphery of the disk 1, and 3 denotes a disk near the disk 1. Is a magnetic resistance element that is fixedly arranged and detects a change in a magnetic field and outputs a pulse signal. The pulse generating means 4 is constituted by the disk 1 and the magnetoresistive element 3. Reference numeral 7 denotes a period measuring unit that measures the period of each pulse signal output from the pulse generating unit 4. Reference numeral 8 denotes a pulse generated by the pulse generation means 4 when the period measurement means 7 makes one reciprocation of the film of the film type gas meter.
Each time a pulse period is measured, a signal is output and a counting unit that switches the output destination of the period measured by the period measuring unit 7. 9 and 10 indicate the period measured by the period measuring unit 7 sent from the counting unit 8. A first cycle storage unit and a second cycle storage unit that store alternately one by one. The cycle storage means 11 is constituted by the count section 7 and the second cycle storage section 10. Reference numeral 12 denotes a cycle measuring unit 7 in the first cycle storage unit 9.
The first period addition unit 13 calculates and stores the total of the eight periods stored when the eight periods measured are stored in the second period storage unit 10. A second cycle addition unit that calculates and stores the sum of the eight stored cycles when the cycle is stored. The first period addition unit 12 and the second period addition unit 13 constitute a period addition unit 14.

Reference numeral 15 denotes the sum of the periods (SUM1) stored in the first period storage unit 9 stored in the first period addition unit 12 based on the signal from the counting unit 8 and the second period addition unit 13 stores the sum. Difference (| SUM1-SUM2) of the sum of the cycles (SUM2) stored in the second cycle storage unit 10
|) Is a determination means for determining whether the gas is flowing at a constant flow rate by performing a magnitude determination based on a preset threshold value. The determination means 15 will be described in detail. For example, when eight cycles are stored in the first cycle storage unit 9 this time, the eight cycles stored in the first cycle storage unit 9 stored in the first cycle addition unit 12 are stored. From the sum of the cycles (SUM1) of the previous cycle stored in the second cycle adder 13
It is determined whether the difference (| SUM1−SUM2 |) from the sum (SUM2) of the eight cycles stored in 0 is greater than 3% of the sum of the cycles stored this time in the first cycle addition unit 12. ing.

In 16, the judgment means 15 is | SUM1-SUM
When it is determined that 2 | is smaller than the preset threshold value, the total of the eight periods (T0 to T7) stored in the period storage unit 11 and the period stored in the period addition unit 14 ( From SUM = T0 + T2 +... + T7), a correction coefficient Pn = Tn × 8 ÷ SUM (n = 0 to 0) for calculating the flow rate corresponding to the storage cycle of the cycle storage unit 11
The correction coefficient calculation unit 17 for calculating 7) is a correction coefficient storage unit for storing the correction coefficient Pn calculated by the correction coefficient calculation unit 16. The correction coefficient calculator 16 and the correction coefficient storage 17 constitute a correction coefficient calculator 18.

Reference numeral 19 denotes a one-second determining unit for outputting a signal when the added value of the period is greater than one second.
When it is determined that SUM1-SUM2 | is smaller than a preset threshold value and when the correction coefficient calculating means 18 calculates the correction coefficient, the sum of the stored cycles and the cycle currently stored in the cycle storage means 11 are calculated. A period addition unit for sequentially adding and storing an added value of the added period;
A correction coefficient addition storage unit 22 for adding and storing the correction coefficient stored in the correction coefficient calculation unit 18 corresponding to the cycle added to the added value of the cycle stored in 0, and a one-second determination unit 22
Reference numeral 9 denotes an instantaneous flow rate calculation unit that calculates an instantaneous flow rate from the addition value of the cycle stored in the cycle addition unit 20 when the signal is output and the addition value of the correction coefficient stored in the correction coefficient addition storage unit 21. Then, from the one-second determining unit 19 to the instantaneous flow rate calculating unit 2
2 constitutes the instantaneous flow rate calculating means 24. A flow rate measuring device is constituted by 5: an integrating processing means for integrating the flow rate, and 6: a safety processing means for monitoring the flow rate and shutting off the gas when it is judged that there is danger in the use condition of the gas.

The operation of the flow rate measuring apparatus according to this embodiment will be described in detail with reference to (Table 1) and (Table 2).

[0014]

[Table 1]

[0015]

[Table 2]

In Table 1, first, the period storage means 11
The operation of will be described in detail. The cycle No. measured by the cycle measuring means 7. m-8-No. At the time when the first cycle storage unit 9 stores up to m−1 in each of T0 to T7, the counting unit 8 switches the output destination of the cycle measured by the cycle measuring unit 7 to the second cycle storage unit 10, and the second cycle The storage unit 10 stores the cycle in T0 to T7. When the second period storage unit 10 stores the period in T7, the counting unit 8 switches the output destination of the period measured by the period measurement unit 7 to the first period storage unit 9 and repeats the same operation.

Next, the period adding means 14 will be described in detail. No. measured by the cycle measuring means 7. When the cycle of m−1 is stored in the first cycle storage unit 9, the first cycle addition unit 12
Is the total value 2017 of the cycles stored in the first cycle storage 9
[Ms] is calculated and the total value is stored. Similarly,
The period measuring means 7 determines the measurement No. When the cycle of m + 7 is measured and stored in the second cycle storage unit 10, the second cycle addition unit 13 calculates the total value 2019 [ms] of the cycles T0 to T7 stored in the second cycle storage unit 10, and calculates Store the total value.

Next, determination means 15 and correction coefficient calculation means 18
The operation of will be described in detail. The period measuring means 7 determines the measurement No. When the counting unit 8 outputs a signal after measuring the period of m + 7, the determination unit 15 determines the addition period 2017 [ms] stored in the first period addition unit 12 and the second period addition unit 1
3 (2)
[Ms]) is smaller than 3% (61 [ms]) of the addition cycle 2019 [ms] stored in the second cycle addition unit 13, so that it is determined that the gas is flowing at a constant flow rate. Then, as shown in FIG. 3, a correction coefficient Pn (n = 0 to 7) = Tn × for the correction coefficient calculation unit 16 to calculate the flow rate corresponding to the cycles T0 to T7 stored in the second cycle storage unit 13. 8
÷ 2019 [ms] is calculated and stored in the correction coefficient storage unit 17.

With the above configuration, the correction coefficient calculating means 18 calculates the correction coefficient Pn (n = 0 to 7) for calculating the flow rate corresponding to the cycles T0 to T7 stored in the cycle storage means 11, thereby obtaining 1 Accurate flow rate per pulse can be measured, enabling highly accurate integration.

Next, the operation of the instantaneous flow rate calculating means 23 will be described in detail. The cycle addition section 20 is the second cycle storage section 10
Is added to the previous addition cycle 0 [ms] stored in the cycle addition unit 20 and the addition cycle 201 [m
s], and the correction coefficient addition storage unit 21 stores the addition correction coefficient 0.000 stored therein and the cycle storage unit 14 added by the current cycle addition unit 20 stored in the correction coefficient storage unit 17.
Is added to the correction coefficient P1 corresponding to the cycle stored in the calculation section to calculate an addition correction coefficient 0.796. Then, the one-second determining unit 20 calculates the addition period 201 [m
s] is longer than one second. As a result, since the period is not longer than one second, the period addition unit 20 and the correction coefficient addition storage unit 2
1 repeats the same operation, and the cycle addition section 20 adds the storage cycles T0 to T3 stored in the second cycle storage section 10 to the addition cycle 1007 [ms], and the correction coefficient addition storage section 21
Calculated the correction coefficient 3.989 by adding P0 to P3, the one-second determining unit 19 determines that the instantaneous flow rate calculating unit 22 has the instantaneous flow rate Fm = 3 because the addition cycle calculated by the addition cycle 20 is one second or more. 0.39 from 0.989 / 1.007 * 0.1
Calculate 6 liters / sec. Thereafter, the same operation is repeated to store the storage periods T4 to T stored in the second period storage unit 10.
The instantaneous flow rate is calculated for 7.

In the above configuration, when the determination means 15 determines that the gas flow rate is constant, the correction coefficient calculation means 18
Operates to calculate the correction coefficient and obtain the flow rate corresponding to each pulse, and the instantaneous flow rate calculating means 23 can calculate the instantaneous flow rate per second.

[0022]

As described above, according to the flow rate measuring device of the present invention, a constant flow rate is caused to flow by calculating a correction coefficient for calculating a flow rate corresponding to each pulse stored in the period storage means. Even if there is no pulse train at regular intervals due to the characteristics of the measurement system, the flow rate can be measured with high resolution, and the determination means determines that the fluid is flowing at a constant flow rate By calculating the correction coefficient every time, a correct correction coefficient can be automatically restored even if a deviation occurs in the correction coefficient corresponding to each pulse due to noise or the like.

Further, the present invention can calculate the instantaneous flow rate per unit time. Therefore, when estimating the usage of the gas appliance from the change in the flow rate, the present invention has the effect of improving the estimation accuracy, and has the effect of improving the accuracy of the gas appliance. Accurately judge abnormal usage and ensure safety.

[Brief description of the drawings]

FIG. 1 is a block diagram of a flow measurement device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional appliance discriminating apparatus.

[Explanation of symbols]

 Reference Signs List 4 pulse generating means 7 cycle measuring means 11 cycle storing means 14 cycle adding means 15 determining means 18 correction coefficient calculating means 23 instantaneous flow rate calculating means

Claims (2)

(57) [Claims] 1. A pulse generating means for outputting a plurality of pulses in conjunction with a mechanical movable part which makes one rotation or one reciprocation every time a constant volume of fluid flows, and measures a pulse period outputted by said pulse generating means. A period measuring unit; a period storing unit that stores a predetermined number of pulse periods output by the period measuring unit; a period adding unit that calculates a total value of the pulse periods stored by the period storing unit; Judgment means for judging whether the fluid is flowing at a constant flow rate based on the total value of the pulse periods calculated by the addition means, and the cycle storage means stores when the judgment means judges that the fluid is flowing at a constant flow rate. And a correction coefficient calculating means for calculating a pulse correction coefficient for calculating a flow rate corresponding to a pulse cycle to be performed. 2. The flow rate measuring device according to claim 1, further comprising: an instantaneous flow rate calculating means for calculating an instantaneous flow rate per unit time from the pulse cycle information stored in the cycle storing means and the correction coefficient calculated by the correction coefficient calculating means. .