KR102074671B1 - Temperature-pressure compensation device for gas meter capable of remote meter reading - Google Patents

Abstract

The present invention relates to a temperature-pressure compensator installed in a gas meter. The temperature-pressure compensator for a gas meter includes: a temperature sensor measuring the temperature (T) of supply gas; a pressure sensor measuring the pressure (P) of the supply gas; a communication means receiving a heating value (Hv) per unit volume in a reference state of the supply gas from the outside; a control part converting a reference gas volume (V_b) from an actual gas volume (V) outputted from a gas meter flowmeter installed in the gas meter, the heating value (Hv) per unit volume, the temperature (T) measured through the temperature sensor and the pressure (P) measured through the pressure sensor; and a display part displaying the reference gas volume (V_b). According to the configuration, provided is a temperature-pressure compensator for a gas meter, which includes a communication means for remote reading and is wirelessly inputted with a gas heating value through wireless communication every month, thereby improving the accuracy in the measurement of gas consumption.

Description

Temperature-pressure compensation device for gas meter capable of remote meter reading}

The present invention relates to a gas meter on-pressure calibrator capable of remote meter reading.

City gas tariffs are based on the volume of gas used by the consumer. The gas supplier charges gas based on the standard usage of gas supplied to each user according to the volume measured at 0 ° C and 1 atmosphere under standard conditions, but the actual gas rate is installed in each user's house or factory. It is calculated according to the measured value of the gas meter.

At this time, the density of the gas is changed by the temperature and pressure in the pipe of the gas meter, and the volume of the gas actually used differs from the gas volume measured at 0 ° C. and 1 atm (hereinafter, referred to as a reference state).

For example, in an environment where the air temperature is higher than 0 ° C. and the air pressure is lower than 1 atm, the measured value displayed by the gas meter will be measured higher than the measured value under standard conditions. However, the gas supplier will assume that the gas meter's measurements are measured under standard conditions and will charge the gas. This may result in the user being marked as having used more gas than the supplier's actual gas supply, which may cause the user to pay more gas bills than they actually are.

In order to solve this problem, on-site pressure compensators are used in the industrial field to convert the volume of the gas measured by the city gas flow meter to the reference state. The gas pressure, gas temperature and compression factor must be known in order to convert the gas volume in use to the gas volume in the reference state.

In order to know the compression factor of the gas in use, it is necessary to know the composition of the gas, but the composition of the gas cannot be measured on-site, and KAC does not disclose it separately. Instead, KOGAS is reporting the heating value of city gas.

Korean Patent No. 10-1785434 discloses an on-pressure compensator that calculates the volume and calorific value of a used gas by simply calculating a compression factor given a calorific value of gas. However, such a temperature pressure compensator is inconvenient to calculate the volume and calorific value of the gas used when the user inputs the calorific value of the gas announced by the Korea Gas Corporation every month.

In addition, while the metering work of the city gas flow meter requires a lot of manpower, the meter reader can not read all the flow meters at the same time, the city gas company may cause a difference in sales volume, consumers consumers the same gas according to the difference in the meter reading time There is a problem that even if you use a different monthly fee.

In addition, flowmeters, pressure gauges, and thermometers are calibrated at regular intervals to ensure measurement accuracy.If the average measurement deviation is less than 1% depending on the measurement range, the flowmeter, pressure gauge, and thermometer are regarded as pass and are not calibrated separately. Does not. However, it is necessary to correct the measurement error through the calibration correction curve as the error within 1% in the flow meter, the pressure gauge, and the thermometer affects the measured value.

In addition, it is necessary to store the gas usage pattern of the place of use in the on-pressure calibrator, and if the actual gas usage deviates by a certain ratio or more from the usage pattern, it is considered to be an emergency situation such as a failure of the gas flowmeter or a breakage of the gas pipe, and then it is necessary to transmit the information.

Republic of Korea Patent No. 10-1785434

Accordingly, the present invention has been invented in view of the above circumstances, and has a communication means to enable remote meter reading, and the city gas heat generation amount can be input by wireless communication every month through such communication means to improve the measurement accuracy of gas consumption. It is an object of the present invention to provide a gas pressure corrector for a gas meter.

The on-pressure compensator for a gas meter according to the present invention for realizing the object as described above, the temperature sensor for measuring the temperature (T) of the supply gas; A pressure sensor for measuring the pressure P of the supply gas; Communication means capable of receiving a heating value (Hv) per unit volume in a reference state of the supply gas from the outside; The actual gas volume (V) output from the gas meter flowmeter installed in the gas meter, the calorific value (Hv) per unit volume, the temperature (T) measured by the temperature sensor and the pressure (P) measured by the pressure sensor A control unit for converting the reference gas volume (V _b ) from the; A display unit displaying the reference gas volume V _b ; It includes.

In addition, the communication means may receive information on the calibration correction curve according to the calibration test of the gas meter flow meter, the temperature sensor or the pressure sensor, the control unit by the actual gas volume (V), the temperature sensor The information on the calibration correction curve is reflected in the measured temperature T or the pressure P measured by the pressure sensor, and the reference gas volume V _b is converted therefrom.

In addition, the communication means may receive information according to the calibration test of the gas meter flow meter, the temperature sensor or the pressure sensor, the control unit generates a calibration correction curve from the information according to the calibration test, the control unit The information on the calibration correction curve is reflected in the actual gas volume (V), the temperature (T) measured by the temperature sensor, or the pressure (P) measured by the pressure sensor, and from there the reference gas volume (V _b ). Convert to

In addition, the control unit stores the information about the actual gas volume (V) in the daily use as a usage pattern for a predetermined period, the gas volume measured by the gas meter flow meter during the day is a predetermined ratio than the gas volume according to the usage pattern When the deviation from the alarm is regarded as an emergency, an alarm is transmitted or the emergency is transmitted to the outside through the communication means.

In addition, the display unit further displays the amount of heat used by multiplying the reference gas volume (V _b ) by the calorific value (Hv) per unit volume.

According to the present invention, there is provided a communication means to enable the remote meter reading, through the communication means that the monthly gas gas heating amount can be input by wireless communication to improve the measurement accuracy of the gas consumption by using a gas pressure calibration device Can provide.

In addition, by applying the information on the calibration correction curve according to the calibration of the flow meter, pressure gauge, thermometer to the on-temperature compensator can provide a gas pressure on-demand compensator that can further improve the measurement accuracy of the gas consumption.

In addition, the gas pressure meter is used to store the gas usage pattern of the place of use in the on-pressure calibrator and to be considered as an emergency situation such as a failure of the gas flow meter or damage to the gas pipe when the actual gas usage is out of a certain ratio from the stored pattern. It is possible to provide a pressure compensator.

1 is a view for explaining the configuration of the on-pressure corrector installed in the gas meter according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an embodiment of a display unit of the on-pressure corrector of FIG. 1.
3 is a diagram illustrating an exemplary calibration correction curve for a gas meter flow meter.
FIG. 4 is a diagram showing a gas usage pattern over time and an exemplary tolerance range of ± 20% for diagnosing a state of use.

Hereinafter, the configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, it should be noted that in adding reference numerals to the elements of each drawing, the same elements are denoted by the same reference numerals as much as possible even if they are shown in different drawings.

The present invention relates to a gas pressure on-temperature corrector, the city gas calorific value can be input by wireless communication every month through the communication means, the control unit converts the gas volume of the use state from the city gas calorific value to the gas volume of the reference state This is to improve the measurement accuracy of gas consumption. In addition, it is possible to reflect the information on the calibration correction curve of the flow meter, thermometer, pressure gauge through the communication means to further improve the measurement accuracy of the gas consumption of the on-pressure calibrator.

Referring to Korean Patent No. 10-1785434, a method of obtaining a specific gravity (SG) of a gas from a calorific value of LNG (or gas) using a simple equation, and a compression factor and a density from a specific gravity of a gas with a very low uncertainty It is described.

PV = ZRT equation (1)

식 (2)

Formula (2)

Here, Hv is a calorific value per unit volume of gas, Xco ₂ is a mole fraction of carbon dioxide, and X _N2 is a mole fraction of nitrogen.

Except for the high-pressure pipe network, most city gas pipe pressure is less than 10 bar and the gas temperature is almost room temperature. In addition, in Korea, which supplies only LNG, only inert gas is nitrogen, and the concentration of nitrogen is about 0.2 mol%, so the composition and conditions of the supply gas are limited to a very narrow width.

Under these conditions, it is possible to predict compression factors relatively accurately without using complex imperial state equations such as SGERG (= AGA 8-gc) and AGA 8-dc to calculate the density or compression factor of the gas. This is because the pressure range is so narrow that the relationship between compression factor, temperature, pressure and specific gravity is nearly linear.

Under these conditions, a regression error with 96 basic data ranging from 0.55 to 0.65, pressure from 1 to 10.5 bar, and temperature from 0 to 30, yielding a maximum regression error of 0.04%. The compression factor equation thus obtained was analyzed to have an uncertainty of 0.12% up to a pressure of 10 bar.

Z = 0.998908 + 1.96133 × 10 ^-3 SG + 3.75575 × 10 ^-3 P + 2.22743 × 10 ^-5 T-0.0109632SG, P-4.45579 × 10 ^-5 SG, T-3.24402 × 10 ^-5 P, T + 1.03154 × 10 ^-4 SGP T equation (3)

Where Z is the actual compression factor in use, SG is the specific gravity of the gas, P is the pressure, and T is the temperature.

The density formula of gas

식 (4-1)

Formula (4-1)

Where p is the actual gas density in use, Z is the actual compression factor, T is the temperature, and M _r is the molar mass of the gas.

In the formula (4-1), the molar mass M _r of the gas has the following relationship with the specific gravity (SG) of the gas.

식 (4-2)

Formula (4-2)

Here, since the ratio of the reference compression factor Z _{b (air)} and the reference compression factor Z _b of the gas in the reference state of air (0 ° C., 1 atmosphere) is close to 1 (≒ 1.0024), this can be regarded as 1. . In addition, since the molar mass M _{r (air)} of _air is a value known as 28.9626 kg / kmol, this is substituted into Equation (4-1) and summarized as Equation (4).

식 (4)

Formula (4)

Standard compression factor of the air in the country commerce reference state (Z _{b (air))} is known as 0.99941, based on the compression factor (Z _b) of the gas using the formula (3) can be determined as follows:

Z _b = 0.998908 + 1.96133 × 10 ^-3 SG + 3.75575 × 10 ^-3 × 1.01325-0.0109632SG × 1.01325SG

Currently, the Korea Gas Corporation website posts the calorific value per unit volume of city gas supplied to customers every month. Since July 2012, the city gas usage fee has been changed from the existing volume unit to the calorie unit, and is charged based on the calorie value multiplied by the calorific value per unit volume. For example, the Korea Gas Corporation website posts 42.917 MJ / Nm ³ (10,251 kcal / Nm ³ ) in March 2016. Here, since the volume of the gas varies with temperature and pressure, Nm ³ means the volume of the gas at 0 ° C. and 1 atmosphere.

When gas is supplied to a customer's home or factory, the density of the gas changes according to the temperature and pressure in the pipe of the gas meter, and the actual gas volume is different from the gas volume at the reference state, that is, 0 ° C and 1 atmosphere. do.

In formula (2),

식 (2)

Formula (2)

And the specific gravity (SG) of the gas is

SG = f (H _v , Xco _{2 ,} X _N2 )

Becomes Where H _v is the calorific value per unit volume of gas, Xco ₂ is the mole fraction of carbon dioxide, X _N2 Is the mole fraction of nitrogen.

In equation (3),

Z = 0.998908 + 1.96133 × 10 ^-3 SG + 3.75575 × 10 ^-3 P + 2.22743 × 10 ^-5 T-0.0109632SG, P-4.45579 × 10-5SG, T-3.24402 × 10-5P, T + 1.03154 × 10- 4SGPT formula (3)

Here, since temperature T and pressure P use a measured value, it becomes Z = F (SG). In the gas (LNG), the molar fraction of nitrogen, which is an inert gas, is about 0.2 mol%, and the molar fraction of carbon dioxide is close to zero, so the influence on the molar fraction of nitrogen and the molar fraction of carbon dioxide is minimal. From this, the actual compression factor Z

Z = F (SG) = F1 (H _v , Xco _{2 ,} X _N2 ) ≒ F2 (H _v )

Can be Therefore, the actual compression factor (Z) can be obtained by a simple equation if only the calorific value (H _v ), the temperature (T) and the pressure (P) per unit volume of the gas.

In the formula (4-1),

식 (4-1)

Formula (4-1)

Where p is the actual gas density in the use state, Z is the actual compression factor, T is the temperature, and M _r is the molar mass of the gas.

In the formula (4-2), the specific gravity (SG) of the gas,

식 (4-2)

Formula (4-2)

And the molar mass M _r of the gas is

M _r = (SGM _{r (air)} Z _b ) / Z _{b (air)} equation (5-1)

Here, since the ratio of the reference compression factor Z _{b (air) of air to} the reference compression factor Z _b of gas is close to 1 (241.0024), considering this as 1, the equation (5-1)

M _r = SGM _{r (air)} Equation (5)

And M _{r (air)} is a value known as 28.9626 kg / kmol. Therefore, the actual gas density ρ is

ρ = F (Z, M _r ) = F1 (SG) ≒ F2 (H _v )

If only the calorific value (H _v ) per unit volume of gas can be obtained by a simple formula.

ρ = M / V equation (6)

M = ρV (7)

Where M is the actual gas mass and V is the actual gas volume. Therefore, the actual gas mass M can be obtained by knowing only the actual gas volume V and the calorific value H _v per unit volume of the gas.

Since the actual gas mass (M) is the same regardless of temperature and pressure,

M = ρ _b · V _b Formula (8)

V _b = M / ρ _b = ₍ ρV) / ρ _b Formula (9)

Where ρ _b is the reference gas density and V _b is the reference gas volume.

ρ _b is obtained from the formula (4-1),

_{ρ b = (P · Mr)} / (Z b · R · (T + 273.15)) (10)

Here, P is 1 atmosphere, T is 0 degreeC, Z _b can be calculated | required using Formula (3), and M _r can be calculated | required using Formula (5). Therefore, the reference gas volume (V _b ) can be obtained from Equation (9) by knowing only the actual gas volume (V) and the calorific value (H _v ) per unit volume of gas.

1 is a view for explaining the configuration of the on-pressure corrector installed in the gas meter according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an embodiment of a display unit of the on-pressure corrector of FIG. 1.

The warm pressure corrector 100 includes a temperature sensor 110, a pressure sensor 120, a display unit 130, a communication unit 140, a controller 150, and an alarm unit 160.

The temperature sensor 110 measures the temperature T of the gas (supply gas) that is actually supplied. The temperature sensor 110 may be installed inside a pipe to which gas is supplied.

The pressure sensor 120 measures the pressure P of the supply gas. The pressure sensor 120 may be installed inside the pipe.

The communication unit 140 may receive the calorific value Hv per unit volume in the reference state of the supply gas from the outside. The reference state is 0 ° C and 1 atmosphere. The calorific value (Hv) per unit volume of gas is posted monthly on the Korea Gas Corporation website.

In addition, the communication means 140 is configured to receive a charge per unit calorie of gas from the outside. The charge per unit calorie may be expressed, for example, as 14.0583 (Won / MJ). The wireless communication network may use, for example, Low Power Wide-Area Network (LPWAN) among various network fields of the IoT market.

The controller 150 measures the actual gas volume V output from the gas meter flowmeter 10 installed in the gas meter, the temperature T measured by the temperature sensor 110, and the pressure sensor 120. Receive information about the pressure (P) being. The actual gas volume (V) can be obtained by summing the number of pulses (actual gas amount) output from the gas meter flowmeter 10, and the temperature sensor 110 and the pressure sensor 120 for each pulse or several pulses. ), The temperature T and the pressure P can be measured.

The control unit 150 is based on the actual compression factor (Z) and the reference from the information on the calorific value (Hv), actual gas volume (V), temperature (T) and pressure (P) per unit volume of gas received by the communication means 140 The compression factor Z _b is calculated and the reference gas volume (or converted gas volume) V _b is converted from the actual compression factor Z and the reference compression factor Z _b .

For the method of converting the reference gas volume (or converted gas volume) V _b from the information on the calorific value (Hv), the actual gas volume (V), the temperature (T) and the pressure (P) per unit volume, refer to the above description. Just do it.

The controller 150 may calculate the amount of heat used by multiplying the reference gas volume V _b by the calorific value Hv per unit volume. In addition, the controller 150 may calculate the amount of use multiplied by the charge per unit calorie.

The display unit 130 displays the reference gas volume V _b converted by the controller 150. In addition, the display unit 130 may further display the amount of heat used by multiplying the reference gas volume V _b calculated by the controller 150 by the calorific value Hv per unit volume. In addition, the display unit 130 may display the amount of use multiplied by the charge per unit calorie calculated by the amount of heat calculated by the controller 150.

According to the on-temperature corrector 100 as described above, the communication means 140 receives the heating value (Hv) per unit volume, the actual gas volume (V) measured by the gas meter flow meter 10, the temperature sensor 110 The reference gas volume (V _b ) can be converted using a simple equation from the information on the temperature (T) measured by the pressure and the pressure (P) measured by the pressure sensor 120.

Therefore, the on-temperature pressure corrector 100 does not need to read the monthly gas consumption by the meter reader, and can eliminate the difference between the actual gas consumption and the gas consumption billed in the bill according to the difference in the meter reading time.

In addition, the display unit 130 of the thermal pressure corrector 100 additionally displays the amount of heat used together with the reference gas volume V _b , so that the user can easily know the usage fee.

3 is a diagram illustrating an exemplary calibration correction curve for a gas meter flow meter.

The flowmeter, pressure gauge and thermometer are calibrated every certain period of time (e.g. one year) to ensure measurement accuracy.If the average measurement deviation is less than 1% depending on the measurement range, the flowmeter, pressure gauge, Do not calibrate the thermometer. However, even if the error within 1% in the flow meter, pressure gauge, and thermometer affects the measured value, the measurement accuracy can be further improved by correcting the measurement error through the calibration correction curve.

Table 1 shows exemplary calibration results of the flow meter.

Flow rate

(m ³ / h) Calibration equipment
Collection
(m ³ ) Standard machine
Collection
(m ³ ) Calibration equipment
pressure
(Abs, kPa) Calibration equipment
Temperature
(K) Measure
Deviation
(%) Average measurement
Deviation
(%) U

(%) 64.82
64.82
64.82 6
6
6 6.048
6.043
6.040 100.412
100.425
100.422 293.21
293.23
293.25 -0.79
-0.71
-0.66
-0.72

0.31
162.13
162.26
162.40 8
8
8 7.979
7.981
7.979 99.930
99.931
99.930 293.31
293.22
293.37 0.26
0.24
0.26
0.25

0.31
258.46
258.46
259.43 13
13
13 12.990
12.991
12.985 100.075
100.067
100.071 293.99
293.92
293.88 0.08
0.07
0.12
0.09

0.31
453.99
453.99
454.96 23
23
23 22.919
22.906
22.910 99.259
99.248
99.259 294.84
294.52
294.69 0.35
0.41
0.39
0.39

0.31
648.56
648.56
650.50 33
33
33 32.957
32.961
32.966 98.037
98.021
97.997 294.73
294.65
294.81 0.13
0.12
0.10
0.12

0.31

Since the average measurement deviation varies nonlinearly according to the flow rate, as shown in FIG. 3, a calibration correction curve can be simply generated by a line connecting the average measurement deviation. Therefore, the measured value can be corrected by reflecting the average measurement deviation obtained from the calibration correction curve in the measured value according to the flow rate. This calibration correction curve can be similarly applied to pressure gauges and thermometers according to the calibration results.

The communication unit 140 may receive information on a calibration correction curve according to a calibration test of the gas meter flow meter 10, the temperature sensor 110, or the pressure sensor 120.

The control unit 150 displays information on the calibration correction curve on the actual gas volume V, the temperature T measured by the temperature sensor 110 or the pressure P measured by the pressure sensor 120 (average measurement deviation). ) And the measured value can be corrected to convert the reference gas volume (V _b ).

On the contrary, the communication unit 140 receives the information according to the calibration test of the gas meter flow meter 10, the temperature sensor 110, or the pressure sensor 120, and the controller 150 corrects the calibration from the information according to the calibration test. You can also create a curve.

The controller 150 reflects the information on the calibration correction curve in the actual gas volume V, the temperature T measured by the temperature sensor 110, or the pressure P measured by the pressure sensor 120. From the measured value can be converted to the reference gas volume (V _b ).

The on-pressure calibrator 100 can obtain a more accurate measurement value by receiving the measurement deviation of the gas meter flowmeter 10, the temperature sensor 110 or the pressure sensor 120 through the communication means 140 to perform correction. .

FIG. 4 is a diagram showing a gas usage pattern over time and an exemplary tolerance range of ± 20% for diagnosing a state of use.

The controller 150 may store information about the actual gas volume V used during the day for a predetermined period as a usage pattern. The usage pattern may store, for example, hourly daily usage for the last month.

The controller 150 considers the emergency situation when the gas volume measured by the gas meter flow meter 10 deviates by a predetermined ratio or more from the gas volume according to the usage pattern during the day. For example, when the gas volume measured by the gas meter flow meter 10 deviates by ± 20% from the gas volume according to the usage pattern, it is considered to be out of the normal use range and is regarded as an emergency situation. Such an emergency situation can be, for example, a failure of a gas flow meter or damage to a gas pipe.

In an emergency situation, the controller 150 may sound an alarm through the alarm unit 160 or transmit an emergency situation to the outside (for example, Korea Gas Corporation, a gas company, etc.) through the communication unit 140.

The on-pressure calibrator 100 stores information on the amount of use of the place of use, and if it is abnormally deviated from the patterned amount of usage by patterning it, it is possible to efficiently deal with the emergency situation.

It will be apparent to those skilled in the art that the present invention is not limited to the above embodiments and can be practiced in various ways within the scope of the present invention without departing from the spirit of the present invention. will be.

10 gas meter flow meter
100: pressure compensation device
110: temperature sensor
120: pressure sensor
130: display unit
140: communication means
145: unit charge input unit
150: control unit
160: alarm unit

Claims (5)

delete In the on-pressure calibrator for gas meter,
A temperature sensor for measuring a temperature T of the supply gas;
A pressure sensor for measuring the pressure P of the supply gas;
Communication means capable of receiving a heating value (Hv) per unit volume in a reference state of the supply gas from the outside;
Actual gas volume (V) output from the gas meter flowmeter installed in the gas meter, the calorific value (Hv) per unit volume, the temperature (T) measured by the temperature sensor and the pressure (P) measured by the pressure sensor A control unit for converting the reference gas volume (V _b ) from the;
A display unit displaying the reference gas volume V _b ;
Including,
The communication means may receive information on the calibration correction curve according to the calibration test of the gas meter flow meter, the temperature sensor or the pressure sensor,
The control unit reflects the information on the calibration correction curve in the actual gas volume (V), the temperature (T) measured by the temperature sensor, or the pressure (P) measured by the pressure sensor, and from there the reference gas volume ( Thermo-pressure compensator installed on the gas meter converting V _b ). In the on-pressure calibrator for gas meter,
A temperature sensor for measuring a temperature T of the supply gas;
A pressure sensor for measuring the pressure P of the supply gas;
Communication means capable of receiving a heating value (Hv) per unit volume in a reference state of the supply gas from the outside;
Actual gas volume (V) output from the gas meter flowmeter installed in the gas meter, the calorific value (Hv) per unit volume, the temperature (T) measured by the temperature sensor and the pressure (P) measured by the pressure sensor A control unit for converting the reference gas volume (V _b ) from the;
A display unit displaying the reference gas volume V _b ;
Including,
The communication means may receive information according to the calibration test of the gas meter flow meter, the temperature sensor or the pressure sensor,
The control unit generates a calibration correction curve from the information according to the calibration test,
The control unit reflects the information on the calibration correction curve in the actual gas volume (V), the temperature (T) measured by the temperature sensor, or the pressure (P) measured by the pressure sensor, and from there the reference gas volume ( Thermo-pressure compensator installed on the gas meter converting V _b ). delete The method according to any one of claims 2 and 3,
And the display unit is installed on a gas meter which additionally displays the amount of heat used by multiplying the reference gas volume (V _b ) by the calorific value (Hv) per unit volume.

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