JP5984457B2 - Gas meter - Google Patents

Description

  The present invention relates to a gas meter installed in each dwelling unit and used for charging a gas fee.

  Currently, the gas charge for each unit is based on the amount of gas (integrated flow rate) used in each unit for a certain period. The reason why such a system is adopted is that, in Japan, the gas supplied to each dwelling unit is strictly adjusted on the gas supply side so as to have a certain amount of heat. This is because if the amount is known, the total amount of heat of the gas used is also clarified, and charging can be performed appropriately. Based on such circumstances, the above-described gas meter that is currently popular is configured to measure only the amount of gas used.

  By the way, in recent years, biogas has been used as an energy source to replace fossil fuels, and in the future, it is expected that gas will be supplied to each dwelling unit from biogas plants established in various places. Is done. In general, the adjustment of the calorific value of gas requires a large amount of cost. Therefore, the heat calorific value adjustment accuracy that is considerably relaxed compared to the conventional calorie calorie adjustment accuracy is adopted and supplied to each dwelling unit. There is a possibility that the calorific value of the gas will fluctuate in each region or at each date and time.

  That is, in the future, there is a possibility that gases having different heat amounts will be supplied to each dwelling unit. In this case, the current gas meter that measures only the gas amount cannot correctly grasp the total heat amount of the used gas and cannot charge appropriately. On the other hand, the apparatus described in Patent Document 1 is known as an apparatus for measuring the amount of heat of high-pressure gas.

Japanese Patent Laid-Open No. 10-185885

  However, the calorific value measuring device described in Patent Document 1 is a large-scale device as a device installed in each general dwelling unit. For example, a pressure sensor that measures absolute pressure is essential for measuring the calorific value. For this reason, if a gas meter having the structure described in Patent Document 1 and capable of measuring the calorific value of the gas is installed in each dwelling unit, a pressure sensor is required for each gas meter, resulting in an increase in cost and an increase in the size of the gas meter. There is a problem of doing.

  That is, in the structure disclosed in Patent Document 1, it is necessary to provide a pressure sensor in order to appropriately measure the total amount of heat of the gas. If the structure is adopted in a gas meter, the gas meter becomes expensive. In addition, there is a problem that the size is increased.

  The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to accurately measure the amount of heat of a gas without separately providing a pressure sensor.

The characteristic configuration of the gas meter according to the present invention includes a flow path through which a measurement target gas flows,
Sonic velocity deriving means for determining the sound velocity of the measurement target gas, temperature measurement means for measuring the temperature of the measurement target gas, pressure deriving means for determining pressure, and instantaneous heat quantity deriving means for deriving the instantaneous heat quantity of the measurement target gas; ,
Atmospheric pressure information holding means for acquiring and holding atmospheric pressure information of the area where the flow path is installed from the outside,
The pressure deriving means obtains a calorific value deriving pressure as the pressure of the measurement target gas from the atmospheric pressure information,
The instantaneous calorific value derivation means is a sonic velocity-caloric relationship index obtained as a relation between the sonic velocity and the calorific value of the measurement target gas, the sonic velocity obtained by the sonic velocity deriving means, the temperature measured by the temperature measuring means, The instantaneous heat quantity is derived based on the heat quantity derivation pressure.

  In general, the atmospheric pressure is almost constant in a certain range (region). For this reason, the atmospheric pressure information of the area where the gas meter is installed can be regarded as equivalent to the pressure of the measurement target gas in the gas meter (atmospheric pressure around the gas meter).

  According to the above characteristic configuration, the atmospheric pressure information of the area where the gas meter is installed is acquired from the outside, the pressure for deriving the amount of heat is obtained based on the atmospheric pressure information, and the pressure for deriving the amount of heat is used for deriving the amount of heat. . That is, the gas meter can derive the instantaneous heat amount without directly measuring the pressure of the measurement target gas by the pressure sensor. At this time, since it is based on the temperature and pressure of the measurement target gas, the instantaneous heat quantity can be accurately derived. Therefore, according to the above characteristic configuration, it is possible to realize a gas meter capable of accurately measuring the amount of heat of a gas without separately providing a pressure sensor.

  The “sound speed” in the present invention means the propagation speed of sound waves in gas.

Here, as the sound speed-heat quantity relationship index, storage means for storing a sound speed-heat quantity relation index created based on the sound speed in a standard state of each of a plurality of standard gases whose heat amounts are known and have different compositions,
Standard sound speed deriving means for deriving a standard sound speed in a standard state from the sound speed obtained by the sound speed deriving means, the temperature measured by the temperature measuring means, and the heat amount deriving pressure,
It is preferable that the instantaneous heat quantity deriving unit derives the instantaneous heat quantity from the sound speed-heat quantity relation index and the standard sound speed.

  According to the above characteristic configuration, in order to derive the instantaneous heat quantity, the storage means only needs to store the sound speed-heat quantity relationship index in the standard state. The instantaneous calorific value can be obtained simply by converting the standard sound velocity into the calorific value, so that the processing capacity required for the control circuit of the gas meter can be suppressed, and a gas meter excellent in cost can be realized.

Further, a unit time passage volume deriving means for obtaining a unit time passage volume that is a volume of the measurement target gas passing through the flow path per unit time, the unit time passage volume, and a temperature measured by the temperature measurement means. And a unit time passage standard volume derivation means for obtaining a unit time passage standard volume which is a passage volume per unit time when converted into a standard state from the pressure for deriving the amount of heat,
It is preferable that a unit time passage heat quantity deriving unit for deriving a unit time passage heat quantity that is a heat quantity of the measurement target gas passing through the flow path per unit time from the instantaneous heat quantity and the unit time passage standard volume is preferably provided. .

  According to the above characteristic configuration, the unit time passage heat quantity is derived from the unit time passage standard volume obtained by converting the unit time passage volume derived by the unit time passage volume deriving means into the standard state, and the instantaneous heat quantity, and thus more accurate. The amount of heat per unit time can be derived. That is, it is possible to realize a gas meter that can measure the amount of heat of gas with higher accuracy.

Here, comprising an elevation information holding means for holding elevation information at a position where the flow path is installed,
It is preferable that the pressure deriving unit is configured to obtain the heat deriving pressure of the measurement target gas from the atmospheric pressure information and the altitude information.

  According to the above characteristic configuration, when the altitude information holding means is provided, the pressure of the measurement target gas in the gas meter is different from the atmospheric pressure information of the area where the gas meter is installed due to the influence of the altitude at the position where the gas meter is installed. Even so, a gas meter capable of measuring the calorific value of gas more accurately by obtaining the pressure for deriving the calorific value from the atmospheric pressure information and the altitude information can be realized.

  In addition, a pair of ultrasonic transmitters / receivers and an ultrasonic wave that propagates ultrasonic waves in the flow of the measurement target gas from one ultrasonic transmitter / receiver to the other ultrasonic transmitter / receiver bidirectionally for each unit time. A flow rate deriving unit for obtaining a flow rate of the measurement target gas from the pair of propagation times obtained by the ultrasonic sensor, and the sound speed deriving unit is obtained by the ultrasonic sensor. The sound velocity of the measurement target gas is obtained from the propagation time, and the flow rate deriving means flows through the flow path in the unit time from the flow velocity obtained by the flow velocity deriving means, the cross-sectional area of the flow path, and the unit time. It is preferable that the flow rate of the measurement target gas is derived.

  According to the above characteristic configuration, both the flow velocity and the sound velocity can be obtained by the ultrasonic sensor, and both the unit time passage volume and the instantaneous heat quantity of the measurement target gas can be obtained based on the flow velocity and the sound velocity. Therefore, for example, an increase in the size of the gas meter can be suppressed as compared with a case where a known flow meter is separately provided as a flow rate deriving unit. That is, it is possible to realize a gas meter that is superior in terms of cost.

It is a block diagram which shows schematic structure of the gas meter which concerns on embodiment of this invention. It is a block diagram which shows the detailed structure of the gas meter which concerns on embodiment of this invention. It is a figure which shows arrangement | positioning of the basic physical-quantity detection means which concerns on embodiment of this invention. It is a figure which shows the measurement principle of a sound speed and a flow velocity. It is a figure which shows the sound speed-heat quantity relationship parameter | index in the case of deriving heat quantity from a sound speed.

1. Outline of Gas Meter An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically illustrates the configuration of a gas meter 1 of the present application. The gas meter 1 is installed in each dwelling unit or the like and includes a flow path 3 through which a gas 2 used in each dwelling unit flows. Here, the gas 2 means a gas to be measured by the basic physical quantity detection means 4 and is supplied from a gas supply source (for example, a city gas manufacturer) to each dwelling unit. Moreover, the flow path 3 is what is called a low voltage | pressure conduit | pipe, the pressure of the gas 2 which flows through the inside is less than 0.1 Mpa, and the thickness is about 5-30 cm in diameter.

  Here, the pressure P of the gas 2 flowing through the flow path 3 is near atmospheric pressure on a flat ground or the like, but a slight difference occurs depending on the altitude at which the gas meter 1 is installed. Since such a difference in pressure affects the derivation of the amount of heat of the gas 2 flowing through the flow path 3, the gas meter 1 in the present embodiment has a pressure derivation means 31 for obtaining the pressure P of the gas 2 flowing through the flow path 3. I have. The pressure deriving means 31 is not a pressure sensor that directly measures the pressure P of the gas flowing in the flow path 3 but is configured to derive the pressure from other information by calculation. In this embodiment, as shown in FIGS. 1 and 2, the pressure deriving unit 31 derives the pressure P of the gas 2 from information held by an atmospheric pressure information holding unit 32 and an altitude information holding unit 33 described later. Is configured to do.

  The gas meter 1 includes basic physical quantity detection means 4 for detecting a physical quantity related to the gas 2 necessary for measuring the flow rate and heat quantity of the gas 2 flowing through the flow path 3. Furthermore, unit time passage volume deriving means 13 for deriving a unit time passage volume ΔV, which is the volume of the gas 2 passing through the flow path 3 per unit time, based on the physical quantity detected by the basic physical quantity detection means 4, and unit time A unit time passage heat amount deriving means 23 for deriving a unit time passage heat amount ΔQ that is the amount of heat of the gas 2 passing through the flow path 3 is provided. Here, “unit time” means a measurement interval of the flow rate and heat quantity of the gas 2 and is a predetermined value. The unit time may be set, for example, between 1 and 5 seconds. In this embodiment, 2 seconds is set. Hereinafter, the unit time is represented by Δt. Further, the gas meter 1 includes a flow rate integrating means 14 for integrating the unit time passage volume ΔV of the gas 2 derived by the unit time passage volume deriving means 13 over a plurality of unit times Δt, and a plurality of unit times Δt. And a calorific value accumulating unit 24 for accumulating the unit 2 passing calorific value ΔQ of the gas 2 derived by the unit-time passing calorie deriving unit 23. These means and various means to be described later are constructed with a microcomputer 5 including a microprocessor and a semiconductor memory as a main device.

  In addition, the gas meter 1 has at least a unit time passage heat amount ΔQ derived by the unit time passage heat amount deriving means 23 so that the operator can visually confirm the state of the gas meter 1 during operations such as meter reading and maintenance inspection. Is provided with an external output means 6 capable of externally outputting. As the external output means 6, for example, a liquid crystal display provided in the gas meter 1 or the like can be used, or a display provided remotely may be used. In this embodiment, the external output means 6 includes a unit time passage heat quantity ΔQ derived by the unit time passage heat quantity derivation means 23, an integrated value ΣΔQ of the heat quantity accumulated by the heat quantity accumulation means 24, and a unit time passage volume derivation means 13. And the flow rate integrated value ΣΔV, which is the integrated value of the unit time pass volume integrated by the flow rate integration means 14, is displayed.

2. Detailed configuration of gas meter 2-1. Basic Physical Quantity Detection Means FIG. 2 shows a detailed configuration of the gas meter 1 of the present application. In the present embodiment, the gas meter 1 includes an ultrasonic sensor 41 and a temperature sensor 42 that measures the temperature T of the gas 2 as the basic physical quantity detection means 4. The ultrasonic sensor 41 includes a pair of ultrasonic transmitters / receivers 51 (FIG. 3), and determines the propagation time for ultrasonic waves to propagate through the flow of gas 2 from one ultrasonic transmitter / receiver 51 to the other ultrasonic transmitter / receiver 51. Each unit time Δt is configured to be captured in both directions.

  Here, the “temperature sensor 42” in the present embodiment corresponds to “temperature measurement means” in the present invention.

  The ultrasonic sensor 41 is configured to obtain a pair of propagation times t1 and t2. A detailed configuration of the ultrasonic sensor 41 will be described with reference to FIGS. 3 and 4. The ultrasonic sensor 41 includes a pair of ultrasonic transmitters / receivers 51 arranged in two locations, upstream and downstream, along the flow path 3. Here, since the pair of ultrasonic transceivers 51 are arranged at different positions in the axis Z direction of the flow path 3, the ultrasonic waves passing between them are affected by the flow velocity v of the gas 2, and from the upstream side. The propagation time of the ultrasonic wave propagated downstream is accelerated, and vice versa.

  In the ultrasonic sensor 41 in the present embodiment, the propagation time in which the ultrasonic wave propagates from the one ultrasonic transmitter / receiver 51 to the other ultrasonic transmitter / receiver 51 in the flow of the product gas can be captured in both directions. (Here, the propagation time of ultrasonic waves from the upstream side to the downstream side (forward propagation time) is t1, and the propagation time of ultrasonic waves propagating in the reverse direction (reverse propagation time) is t2. And)

2-2. Derivation of the unit time passage volume ΔV In order to derive the unit time passage volume ΔV, the gas meter 1 includes a flow velocity deriving means 11 for obtaining the flow velocity v of the gas 2 from the pair of propagation times t1 and t2 obtained by the ultrasonic sensor 41. I have. The unit time passage volume deriving means 13 is configured to obtain the unit time passage volume ΔV from the flow velocity v obtained by the flow velocity deriving means 11, the cross-sectional area S of the flow path 3 and the unit time Δt.

  More specifically, the gas meter 1 calculates the instantaneous flow rate vS (the instantaneous value of the flow rate at the measurement timing by the ultrasonic sensor 41), which is the product of the flow velocity v obtained by the flow velocity deriving means 11 and the cross-sectional area S of the flow path 3. The required instantaneous flow rate deriving means 12 is provided. The unit time passage volume deriving unit 13 is configured to obtain, as the unit time passage volume ΔV, vSΔt that is the product of the instantaneous flow rate vS obtained by the instantaneous flow rate deriving unit 12 and the unit time Δt.

  Here, the process in which the flow velocity deriving means 11 derives the flow velocity v of the gas 2 from the pair of propagation times t1 and t2 is as follows. As shown in FIG. 4, the pair of ultrasonic transmitters / receivers 51 provided in the ultrasonic sensor 41 has a fixed positional relationship, so that the propagation times t1 and t2 for propagating between the ultrasonic transmitters / receivers 51 with each other are fixed. Is represented by Formula 1 and Formula 2 shown in FIG. Here, L is the distance of the propagation path shown in FIG. 4, Z is the axial direction of the tubular flow path 3, C is the flow velocity of the gas 2, and v is the speed of sound in the gas 2.

  Since Equations 1 and 2 are binary simultaneous equations, as shown in Equations 3 and 4, the sound velocity C and the flow velocity v can be obtained from a pair of propagation times t1 and t2. That is, the above-described flow velocity deriving unit 11 obtains the flow velocity v from the pair of propagation times t1 and t2 by performing the processing of Equation 3.

2-3. Derivation of pressure When the unit time passage heat quantity deriving means 23 derives the unit time passage heat quantity ΔQ, the pressure information of the gas 2 is required as described above. Hereinafter, the pressure deriving means 31 for obtaining the pressure of the gas 2 will be described in detail based on FIG. 1 and FIG.

2-3-1. Configuration for Deriving Pressure In order to derive the pressure of the gas 2 by the pressure deriving means 31, the gas meter 1 includes at least atmospheric pressure information holding means 32 for holding atmospheric pressure information of the area where the gas meter 1 is installed. Yes. Here, the area where the gas meter 1 is installed means an area where the atmospheric pressure at each point in the area can be regarded as the same. As atmospheric pressure information, for example, in Japan, atmospheric pressure data (sea surface correction atmospheric pressure) for each international point number provided by the Japan Meteorological Agency can be used.

The atmospheric pressure information holding means 32 is atmospheric pressure information acquired from the outside (the above-mentioned “atmospheric pressure information of the area where the gas meter 1 is installed”). In this embodiment, the atmospheric pressure information is the sea level correction pressure P described later. ₍ Obtained in the ₀ state). In the present embodiment, as shown in FIG. 1, the gas meter 1 includes a communication unit 34 for communicating with an external server 61. The communication means 34 may be any network that can communicate at least in one direction from the server 61 to the gas meter 1 regardless of whether it is wired or wireless. With such a configuration, the gas meter 1 can receive atmospheric pressure information transmitted from the external server 61 and hold it in the atmospheric pressure information holding means 32.

  Further, in the present embodiment, the gas meter 1 is provided with altitude information holding means 33 that holds altitude information at a position where the gas meter 1 is installed. Here, since the altitude information at the position where the gas meter 1 is installed basically does not change after the installation, it is preferable that the altitude information is configured to be input in advance when the gas meter 1 is installed. Specifically, when the gas meter 1 is installed, it is preferable that the operator uses the altitude information acquisition unit 8 to acquire altitude information and input the information to the altitude information holding unit 33. Here, as the altitude information acquisition means 8, for example, GPS can be used.

2-3-2. Pressure Derivation Method The pressure P of the gas 2 in the flow path 3 of the gas meter 1 is derived as follows. The atmospheric pressure Ph at the altitude h where the gas meter 1 is installed is ICAO determined by the International Civil Aviation Organization (ICAO), assuming that the average seawater pressure (sea surface pressure correction) is P ₀ and the temperature is 288K. In the standard atmosphere, the following formula Ph = P ₀ × {(288−0.0065 · h) / 288} ^5.25
Is required. Therefore, the pressure deriving means 31 uses the above equation to calculate the gas from the atmospheric pressure information (P ₀ ) held in the atmospheric pressure information holding means 32 and the altitude information (h) held in the altitude information holding means 33. It is comprised so that the pressure (Ph) of 2 may be calculated | required.

  Here, the pressure (Ph) of the gas 2 obtained by the pressure deriving means 31 corresponds to the “heat amount deriving pressure” in the present invention. The pressure of the gas 2 flowing in the gas meter 1 is normally supplied with a width of about several tens of hPa with respect to the atmospheric pressure, so that the amount may be corrected as appropriate.

3. Derivation of the unit time passage heat amount ΔQ The gas meter 1 obtains the sonic velocity derivation means for obtaining the sonic velocity C in the gas 2 from the pair of propagation times t1 and t2 obtained by the ultrasonic sensor 41 in order to derive the unit time passage heat amount ΔQ. 21 and a temperature sensor 42 for measuring the temperature T of the gas 2 passing through the flow path 3. Further, the gas meter 1 determines the gas 2 based on the sound speed-heat quantity relationship index f (C ₀ ) obtained as a relation between the sound speed C ₀ and the heat quantity in the standard state of the gas 2 and the sound speed C obtained by the sound speed deriving means 21. Instantaneous heat quantity deriving means 22 for deriving the instantaneous heat quantity Q is provided.

More specifically, the sound speed C obtained by the sound speed deriving means 21 includes the temperature T of the gas 2 obtained by the temperature sensor 42 by the standard sound speed deriving means 21x and the pressure (Ph) of the gas 2 obtained by the pressure deriving means 31. Is converted into the sound speed C ₀ in the standard state, and the instantaneous heat quantity deriving means 22 derives the instantaneous heat quantity Q from the sound speed-heat quantity relationship index f (C ₀ ) based on the sound speed C ₀ .

  Further, the unit time passage heat quantity deriving means 23 is based on the instantaneous heat quantity Q derived by the instantaneous heat quantity derivation means 22 and the unit time passage volume ΔV derived by the unit time passage volume derivation means 13. It is comprised so that (DELTA) Q may be calculated | required.

  More specifically, the unit time passage volume ΔV derived by the unit time passage volume deriving unit 13 is calculated by the temperature T of the gas 2 acquired by the temperature sensor 42 by the unit time passage standard volume deriving unit 13 x and the pressure deriving unit 31. The unit time passage volume ΔV0 in the standard state is converted using the obtained pressure 2 of the gas 2 (Ph), and the unit time passage heat amount deriving means 23 calculates the unit time passage heat amount ΔQ from the unit time passage volume ΔV0 and the instantaneous heat amount Q. To derive.

  Hereinafter, the derivation of the unit time passage heat quantity ΔQ by the unit time passage heat quantity derivation means 23 in the present embodiment will be described in more detail. First, the derivation of the instantaneous heat quantity Q will be described before describing the derivation of the unit time passage heat quantity ΔQ.

The gas meter 1 includes storage means 25 for storing a sonic velocity-caloric relationship index f (C ₀ ) obtained as a relationship between the sonic velocity and the calorific value of each of a plurality of gases having different calorific values and having different compositions. Here, as “a plurality of gases whose amounts of heat are known in advance and having different compositions”, a gas that can be the gas 2 passing through the flow path 3 may be selected. In the present embodiment, a gas having a heat quantity of 40 to 46 MJ / Nm ³ is selected. The speed of sound C ₀ in the standard state of these gases is as follows.

In FIG. 5, each point when the values in Table 1 are plotted on a graph in which the vertical axis indicates the amount of heat in the standard state and the horizontal axis indicates the speed of sound in the standard state (0 ° C., 1 atm), An example of the stored sound velocity-heat quantity relationship index f (C ₀ ) is shown. In the figure, a correlation line indicated by a solid line corresponds to the relationship index f (C ₀ ). In the present embodiment, the correlation line shown in FIG. 5 is represented by a primary correlation equation. Here, the primary correlation equation is obtained from the values in Table 1 by the least square method.

Further, the standard sound speed deriving means 21x the gas meter 1 comprises the sound velocity C of acoustic velocity deriving means 21 is determined, the standard state (0 ° C., 1 atm) using equation 1 is converted into acoustic velocity C ₀ at.

Here, R is a gas constant, T is an absolute temperature [K], M is a molecular weight of the gas, and γ is a specific heat ratio. In gas 2 at a certain moment, R, M, and γ have constant values, and at a certain moment, the sound velocity C of gas 2 is considered to be proportional to T ^1/2 . As described above, the standard sound speed deriving means 21x can derive the sound speed C ₀ in the standard state (0 ° C.) from the sound speed C at a certain moment and the temperature T at that time from Equation 1.

With the above configuration, as shown in FIG. 2, the instantaneous calorific value deriving means 22 instantaneously uses the sonic velocity-heat quantity relationship index f (C ₀ ) stored in the storage means 25 and the sonic velocity C ₀ derived by the standard sonic velocity deriving means 21x. The amount of heat Q is obtained.

Next, the derivation of the unit time passage heat amount ΔQ will be described. In deriving the unit time passage heat quantity ΔQ, the unit time passage standard volume deriving means 13x uses the equation 2 (ideal gas equation of state) as a standard to calculate the unit time passage volume ΔV derived by the unit time passage volume deriving means 13. Converted to a unit time passing volume ΔV ₀ in the state (0 ° C., 1 atm).

Here, the pressure P of the gas 2 obtained by the pressure deriving means 31 as described above corresponds to the pressure P in the flow path 3, and V corresponds to the unit time passage volume ΔV. T is an absolute temperature. N represents the number of moles of gas 2 and R represents a gas constant. Therefore, by using the temperature T of the gas 2 measured by the temperature sensor 42, the unit time passage standard volume deriving means 13x can derive the unit time passage volume ΔV ₀ in the standard state.

The unit time passage heat quantity deriving means 23 multiplies the unit time passage volume ΔV ₀ in the standard state obtained by the unit time passage standard volume derivation means 13x by the instantaneous heat quantity Q derived by the instantaneous heat quantity derivation means 22 to thereby pass the unit time passage. The amount of heat ΔQ is derived.

4). Other Configurations As shown in FIG. 2, the gas meter 1 includes a flow rate integrating unit 14 that holds a flow rate integrated value ΣΔV that is an integrated value of the unit time passing volume ΔV obtained by the unit time passing volume deriving unit 13, and unit time passing. And a calorific value integrating means 24 for holding a calorific value integrated value ΣΔQ, which is an integrated value of the unit time passing heat quantity ΔQ obtained by the calorific value deriving means 23. The flow rate integrating means 14 and the heat quantity integrating means 24 are configured to hold the integrated value of the unit time passage volume ΔV and the integrated value of the unit time passage heat quantity ΔQ over a long period of time. The period here is set to, for example, 10 years.

  With the configuration as described above, the gas meter 1 according to the present invention can be used as a gas meter used for charging a gas charge.

[Other Embodiments]
(1) In the said embodiment, the example in case the gas meter 1 was provided with the altitude information holding means 33 was demonstrated. However, the embodiment of the present invention is not limited to this. That is, the pressure deriving unit 31 may be configured to obtain the pressure of the gas 2 based only on the atmospheric pressure information holding unit 32. The gas meter 1 configured in this way is, for example, a place where the value of atmospheric pressure information (atmospheric pressure) acquired from the outside can be used as it is as the pressure of the gas 2 (for example, it has not been corrected to the sea level correction atmospheric pressure). It is good to use only in the case of atmospheric pressure information in the meaning including altitude).

(2) In the above-described embodiment, an example has been described in which the atmospheric pressure information holding unit 32 is configured to acquire the sea level correction atmospheric pressure from the outside. However, the embodiment of the present invention is not limited to this. That is, the atmospheric pressure information holding unit 32 may be configured to acquire an atmospheric pressure value at a specific altitude in an area where the gas meter 1 is installed. Even in this case, the pressure can be converted into the pressure at the position where the gas meter 1 is installed using the ICAO standard atmosphere.

(3) In the embodiment described above, an example in which the atmospheric pressure information holding unit 32 acquires atmospheric pressure information from an external server has been described. However, the embodiment of the present invention is not limited to this. For example, when the gas meter 1 is installed in a place where it is difficult to directly communicate with an external server, the atmospheric pressure information is obtained from the surrounding gas meter 1 by P2P communication using the short-range wireless communication technology. It does not matter.

(4) In the above embodiment, the ultrasonic sensor 41 is configured to obtain a pair of propagation times t1 and t2, and the sound velocity deriving means 21 is configured to derive the sound velocity C using the propagation time reciprocal difference method. Explained the example. However, the embodiment of the present invention is not limited to this. For example, the ultrasonic sensor 41 may be configured to obtain a pair of frequencies between the ultrasonic transmitter / receiver 51, and the sound speed deriving unit 21 may be configured to derive the sound speed C using a sing-around method.

(5) In the above embodiment, in the case where the storage means 25 stores the sonic velocity-caloric relationship index created based on the sonic velocity in the standard state of each of a plurality of standard gases whose calories are known and have different compositions. An example was explained. However, the embodiment of the present invention is not limited to this. That is, the instantaneous calorific value deriving unit 22 includes the sonic velocity-caloric relationship index, the sonic velocity C derived by the sonic velocity deriving unit 21, the temperature T of the gas 2 acquired by the temperature sensor 42, and the gas obtained by the pressure deriving unit 31. It is sufficient that the instantaneous heat quantity Q can be derived from the pressure (Ph) of 2, and the deriving method is not limited to that described in the above embodiment.

  Specifically, for example, the temperature T of the gas 2 acquired by the temperature sensor 42 among the sonic velocity-heat quantity relationship index (or relational expression) of each standard gas under a plurality of pressure / temperature conditions prepared in advance is used. The instantaneous heat quantity Q may be derived from the sound speed C using a sound speed-heat quantity relation index (or relational expression) that matches the pressure (Ph) of the gas 2 obtained by the pressure deriving means 31.

  In this case, the storage means 25 may store the sound velocity-heat quantity relationship index of each standard gas under a plurality of pressure / temperature conditions. Alternatively, the storage means 25 may not be provided, and the instantaneous heat quantity Q may be derived based on the temperature T, pressure (Ph), and sound speed C of the gas 2 directly from a plurality of sound speed-heat quantity relationship index relational expressions. Absent.

  The present invention can be applied to a gas meter installed in each dwelling unit and used for charging a gas fee.

1: Gas meter 2: Gas 3: Flow path 6: External output means 11: Flow rate derivation means 13: Unit time passage volume derivation means 14: Flow rate integration means 21: Sonic speed derivation means 22: Instantaneous heat quantity derivation means 23: Unit time passage heat quantity Deriving means 24: Calorific value integrating means 25: Storage means 41: Ultrasonic sensor 42: Temperature sensor 51: Ultrasonic transceiver

Claims (5)

A flow path through which the gas to be measured flows,
Sonic velocity deriving means for determining the sound velocity of the measurement target gas, temperature measurement means for measuring the temperature of the measurement target gas, pressure deriving means for determining pressure, and instantaneous heat quantity deriving means for deriving the instantaneous heat quantity of the measurement target gas; ,
Atmospheric pressure information holding means for acquiring and holding atmospheric pressure information of the area where the flow path is installed from the outside,
The pressure deriving means obtains a calorific value deriving pressure as the pressure of the measurement target gas from the atmospheric pressure information,
The instantaneous calorific value derivation means is a sonic velocity-caloric relationship index obtained as a relation between the sonic velocity and the calorific value of the measurement target gas, the sonic velocity obtained by the sonic velocity deriving means, the temperature measured by the temperature measuring means, A gas meter for deriving the instantaneous heat quantity based on a heat quantity derivation pressure. Storage means for storing, as the sound speed-heat quantity relationship index, a sound speed-heat quantity relation index created based on the sound speed in the standard state of each of a plurality of standard gases whose amounts of heat are known and have different compositions,
Standard sound speed deriving means for deriving a standard sound speed in a standard state from the sound speed obtained by the sound speed deriving means, the temperature measured by the temperature measuring means, and the heat amount deriving pressure,
The gas meter according to claim 1, wherein the instantaneous calorific value deriving unit derives the instantaneous calorific value from the sonic velocity-caloric relationship index and the standard sonic velocity. A unit time passage volume deriving means for obtaining a unit time passage volume that is a volume of the measurement target gas passing through the flow path per unit time; the unit time passage volume; and the temperature measured by the temperature measurement means; A unit time passage standard volume deriving means for obtaining a unit time passage standard volume that is a passage volume per unit time when converted into a standard state from the pressure for deriving calorific value,
The unit time passage calorific value deriving means for deriving a unit time passage calorie that is a calorie of the measurement target gas that passes through the flow path per unit time from the instantaneous heat amount and the unit time passage standard volume. 2. The gas meter according to 2. Elevation information holding means for holding elevation information at a position where the flow path is installed,
The gas meter according to any one of claims 1 to 3, wherein the pressure deriving unit is configured to obtain the calorific value deriving pressure of the measurement target gas from the atmospheric pressure information and the altitude information. A pair of ultrasonic transceivers;
An ultrasonic sensor that captures in two directions the propagation time of the ultrasonic wave propagating in the flow of the measurement target gas from one ultrasonic transceiver to the other ultrasonic transceiver;
From the pair of propagation times obtained by the ultrasonic sensor, a flow velocity deriving means for obtaining a flow velocity of the measurement target gas,
The sound speed deriving means obtains the sound speed of the measurement target gas from the pair of propagation times obtained by the ultrasonic sensor,
The unit time passage volume deriving means derives the flow rate of the measurement target gas flowing through the flow path during the unit time from the flow velocity obtained by the flow velocity deriving means, the cross-sectional area of the flow path, and the unit time. The gas meter according to claim 3 constituted.

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