JP2019144061A - Calibrator and calibration method - Google Patents

Abstract

To provide a calibrator for hydrogen or other gas filling devices, with which it is possible to accurately measure the filled amount of a gas (e.g., hydrogen) that is filled with high pressure, even when the capacity of a filling container or a tank fluctuates before and after hydrogen filling.SOLUTION: The calibrator comprises: a filling container (2) in which a high pressure fuel gas (e.g., hydrogen gas) is supplied to the inside of a measurement housing (1) from the outside; a balance (3) for measuring the weight of the fuel gas supplied to the filling container (2); and a controller (CU). The controller (CU) has the function to eliminate, on the basis of a change of the capacity of the filling container (2) in the measurement housing (1), an error due to a change of the buoyance of a gas in the measurement housing (1) before and after the fuel gas is filled.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a calibration device for a gas filling device such as hydrogen, and more particularly to a calibration device capable of accurately measuring a filling amount of a fuel gas such as hydrogen filled with high pressure.

Gasoline measuring machines installed at gas stations are required to have a flow rate verification every 7 years in order to maintain fair business transactions. Yes. In response to such a request, the applicant has proposed a gasoline measuring machine having a flow meter inspection function (Patent Document 1).
In recent years, as a countermeasure against environmental problems, a fuel cell vehicle using hydrogen as a fuel has been developed, and accordingly, a hydrogen filling device and a calibration device for the hydrogen filling device are being studied.

When calibrating the hydrogen filling device, compare the weight before and after filling the calibration device with hydrogen, find the hydrogen filling amount (weight) from the difference, and compare it with the filling amount by the flow meter of the hydrogen filling device. There are types that perform calibration by
In filling with hydrogen, high pressure filling is performed in order to shorten the filling time. However, the temperature rises with high pressure filling, and the fuel tank of the fuel cell vehicle may become hot and break. To eliminate such a possibility, the hydrogen is cooled to −40 ° C. by a cooling device and filled.
Here, when hydrogen is cooled to −40 ° C. and filled in the calibration device of the hydrogen filling device, the temperature of the calibration device changes from a low temperature to a high temperature, and as a result, the buoyancy of the surrounding gas to the calibration device varies. A calibration device of the type that measures the weight of filled hydrogen due to such buoyancy fluctuations has a problem that an error occurs in the measured hydrogen filling amount (weight).

In order to solve this problem, the present applicant has proposed a calibration apparatus and a calibration method that enable accurate calibration by correcting buoyancy fluctuations with respect to the measured hydrogen filling amount (weight) (Patent Literature). 2).
Although this technique (Patent Document 2) is effective, it is assumed that the filling container (tank) used in the calibration apparatus according to this technique is manufactured from a material whose volume does not fluctuate before and after hydrogen filling. ing. In recent years, however, filling containers and tanks used in calibration devices and vehicles have been manufactured from flexible materials whose volume varies with the hydrogen filling pressure. When the volume of the filling container or tank fluctuates before and after hydrogen filling, the above-described calibration technique (calibration apparatus and calibration method according to Patent Document 2) accurately grasps fluctuations in buoyancy and executes high-precision calibration. There is a problem that it becomes difficult.

JP 7-33197 A JP 2017-67472 A

  The present invention has been proposed in view of the above-described problems of the prior art, and is a calibration device for a gas filling device such as hydrogen, even if the volume of the filling container or tank fluctuates before and after hydrogen filling, An object of the present invention is to provide a calibration device and a calibration method capable of accurately measuring the filling amount of a gas (such as hydrogen) filled with high pressure.

The calibration device (100) of the present invention comprises:
A filling container (2) to which high-pressure fuel gas (for example, hydrogen gas) is supplied from the outside in the measurement housing (1), and a balance (3) for measuring the weight of the fuel gas supplied to the filling container (2) And a control unit (CU),
The control unit (CU) determines that the buoyancy of the gas (dry air, nitrogen) in the measurement housing (1) is based on the change in volume of the filling container (2) in the measurement housing (1). It has a function of eliminating an error caused by fluctuations before and after filling.
And the calibration method of the fuel gas filling device (40) using the calibration device (100: the calibration device of claim 1) is:
Measuring the weight of the measurement housing (1) before and after fuel gas filling;
Due to the weight difference of the measurement housing (1) before and after the fuel gas filling, the gas (dry air, nitrogen) of the measurement housing (1) is changed based on the change in the volume of the filling container (2) in the measurement housing (1). It is characterized by having a step of eliminating an error caused by fluctuation of buoyancy before and after filling with fuel gas (for example, hydrogen).

In the present invention, the control unit (CU) uses the buoyancy of the gas (dry air, nitrogen) in the measurement housing (1) as fuel based on the change in the volume of the filling container (2) in the measurement housing (1). When eliminating errors due to fluctuations before and after filling with gas (eg hydrogen),
Only the buoyancy acting on the total volume (Q: solid volume) of the devices (for example, the filling container 2, the balance 3, the pedestal 8, and the filling gas supply line 7) accommodated in the measurement housing (1) is calculated. Function and
Based on the pressure of the filling container (2) in the measurement housing (1) (the discharge pressure of the fuel gas filling device 40, the pressure of the hydrogen pipe 42 or the filling gas supply line 7, etc.), the volume of the filling container (2) is reduced. It preferably has a function to determine.

Also in the calibration method of the present invention, the inside of the measurement housing (1) is based on the change in the volume of the filling container (2) in the measurement housing (1) due to the difference in weight of the measurement housing (1) before and after the fuel gas filling. Calculation of the buoyancy of gas (dry air, nitrogen) in the measurement housing (1) in the process of eliminating the error caused by fluctuations in the buoyancy of gas (dry air, nitrogen) before and after filling with fuel gas (eg, hydrogen) Is the total volume (Q: solid volume: filled container in the housing 1) of the devices (for example, the filled container 2, the balance 3, the pedestal 8, and the filled gas supply line 7) accommodated in the measurement housing (1). 2, the volume occupied by the balance 3, the pedestal 8, the filling gas supply pipe line 7 and the like: does not include the volume of the material constituting the measurement housing 1)
Based on the pressure of the filling container (2) in the measurement housing (1) (the discharge pressure of the fuel gas filling device 40, the pressure of the hydrogen pipe 42 or the filling gas supply line 7, etc.), the volume of the filling container (2) is reduced. It is preferable to determine.

In carrying out the present invention, when obtaining the buoyancy of the gas (dry air, nitrogen) in the measurement housing (1), the temperature of the gas on the surface of the filling container (2) is obtained, and the density of the gas (ρ ) Is preferably determined.
And it is preferable that the dry gas pipe (4) for supplying the dry gas into the measurement housing (1) is detachably provided (with respect to the measurement housing 1).
Here, the scale (3) preferably measures the weight of the fuel gas supplied to the filling container (2) together with the measuring housing (1).

In the present invention, the measurement housing (1) preferably has a semi-hermetic structure.
Here, the term “semi-hermetic structure” means a structure that is not completely sealed, but can be almost sealed.

In the present invention, it is preferable to provide a dew point meter (5) for measuring the dew point temperature in the measurement housing (1).
The dew point meter (5) can be detachably provided outside the measurement housing (1), but can also be provided in the measurement housing (1).
In carrying out the present invention, nitrogen and dry air can be used as the dry gas.

According to the present invention having the above-described configuration, even if the volume of the filling container (2) fluctuates before and after filling with fuel gas (for example, hydrogen), the volume of the filling container (2) is determined from the pressure of the filling container (2). The buoyancy due to the gas (dry air, nitrogen) in the measurement housing (1) has a function of eliminating an error due to fluctuation before and after the fuel gas filling, or the error is eliminated. Since the process (control or procedure) is executed, it is possible to prevent an error in the measurement result of the fuel gas filling amount (weight) even if the volume of the filling container (2) fluctuates before and after the fuel gas filling. .
As a result, in the measurement of the fuel gas filling amount (weight) that is required to be measured with high accuracy, the adverse effect of the buoyancy fluctuation can be eliminated, thereby improving the accuracy of determining the fuel gas filling amount (weight). Thus, the calibration accuracy of the hydrogen gas filling device (40) can be improved.

Here, the relationship between the volume of the filling container (2) in the measurement housing (1) and the pressure (the discharge pressure of the fuel gas filling device 40, the pressure of the hydrogen pipe 42 or the filling gas supply line 7, etc.) is constant. For this reason (there is often a so-called “linear” relationship), the volume of the filling container (2) can be accurately determined by obtaining the pressure of the filling container (2). Furthermore, it is a device (for example, a filling container 2, a scale 3, a pedestal 8, a filling gas supply line 7 or the like) accommodated in the measurement housing (1), and the volume of the device involved in the fluctuation of the buoyancy. The sum (Q, solid volume) can be determined.
And when removing the bad influence by the fluctuation | variation of the buoyancy by the gas in a measurement housing (1), the apparatus (For example, the filling container 2, the balance 3, the base 8, the filling gas supply pipe | tube) accommodated in the measurement housing (1). Road 7 etc .: The solid volume (Q) is excluded from the volume of the measurement housing (1), taking into account only the buoyancy that affects the total volume (Q: solid volume) of the volume whose equipment is involved in the fluctuation of the buoyancy. The buoyancy of the gas acting on the volume (AQ: volume of the device not involved in the buoyancy fluctuation) is not taken into consideration. If calibrated in that way, it was well matched with the results of research and experiments by the inventors.
The buoyancy of the gas acting on the volume (AQ) obtained by subtracting the solid volume (Q) from the volume of the measurement housing (1) is obtained by measuring the weight of the measurement housing (1) before and after the fuel gas filling and calculating the weight difference. It is estimated that it is not involved in buoyancy fluctuations. In other words, when the buoyancy variation is taken into consideration, if the processing includes the buoyancy of the gas acting on the volume (AQ) obtained by removing the solid volume (Q) from the volume of the measurement housing (1), the buoyancy variation The amount becomes inaccurate.

When obtaining the buoyancy of the gas (dry air, nitrogen) in the measurement housing (1), the temperature of the gas in the measurement housing (1) varies greatly depending on time and measurement position. Accordingly, the density (ρ) of the gas and the buoyancy due to the gas also change.
In the present invention, when obtaining the buoyancy of the gas (dry air, nitrogen) in the measurement housing (1), the temperature of the gas on the surface of the filling container (2) is obtained, and the density (ρ) of the gas is calculated from the temperature of the gas. If determined, the gas temperature on the surface of the filling container (2) can be adopted as the representative value of the gas temperature, and the gas density (ρ) can be determined from the representative value. Thereby, the buoyancy due to the gas in the measurement housing (1) can be accurately obtained regardless of the change in the gas temperature due to the time and the measurement position, and the error due to the fluctuation of the buoyancy can be eliminated.
And according to the inventor's research and experiment, the result of determining the gas density (ρ) with the temperature of the gas on the surface of the filled container (2) as a representative value and the complicated calculation considering heat transfer, radiation, and time passage It was confirmed that the obtained gas density (ρ) coincided with high accuracy. In other words, if the gas density (ρ) is determined using the temperature of the gas on the surface of the filled container (2) as a representative value, it does not require complicated calculations that take into account heat transfer, radiation, and time, with the same degree of accuracy. The influence of buoyancy can be calculated and calibrated.

It is a block diagram which shows embodiment of this invention. It is a functional block diagram which shows the control unit in embodiment. It is a flowchart which shows the procedure of the calibration in embodiment. It is a flowchart which shows the control which correct | amends the weight measured in consideration of the buoyancy in the embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
In FIG. 1, a calibration apparatus according to an embodiment of the present invention is indicated generally by the reference numeral 100. The calibration device 100 includes a measurement housing 1, a filling container 2 that is disposed in the measurement housing 1 and is supplied with high-pressure fuel gas (for example, hydrogen gas) from the outside, a scale 3 that measures the weight of the measurement housing 1, a measurement housing 1, A main body housing 20 for housing the scale 3 is provided.
The filling container 2 is placed on the bottom surface of the measurement housing 1 via the base 8. The filling container 2 is made of a flexible material whose volume varies depending on the filling pressure of the fuel gas. Therefore, the volume of the filling container 2 fluctuates before and after the fuel gas is filled.

The weight of the hydrogen gas supplied to and filled in the filling container 2 is measured by the balance 3 by measuring the weight of the measurement housing 1 before filling the fuel gas (for example, hydrogen gas) and the weight of the measurement housing 1 after filling the fuel gas. Then, the weight of the filled fuel gas (for example, hydrogen gas) is obtained from the difference between the two.
Hereinafter, a case where hydrogen gas is employed as the fuel gas will be described.
The measurement housing 1 accommodates a filling container 2 and the like, and the main body housing 20 that accommodates the measurement housing 1 and the scale 3 includes a moving means 20A (wheels or the like) on the lower surface thereof, and a hydrogen filling device 40 to be calibrated at the time of calibration. It is possible to move to the installation location.

A receptacle 6 (hydrogen receiving port) is provided on the side surface of the measurement housing 1, and when the hydrogen gas is supplied to the filling container 2 in the measurement housing 1 from the hydrogen filling device 40 to be calibrated and filled, the receptacle 6 is attached to the measurement housing 1. 1 side hydrogen receiving port.
In other words, the hydrogen filling device 40 and the measurement housing 1 are connected by the coupling of the filling nozzle 41 and the receptacle 6, and hydrogen gas is supplied from the hydrogen filling device 40 to the filling container 2 in the measurement housing 1. Reference numeral 42 denotes a hydrogen pipe.

In the measurement housing 1, the receptacle 6 and the filling container 2 are connected by a filling gas supply line 7. The hydrogen gas supplied from the receptacle 6 into the measurement housing 1 is supplied and filled into the filling device 2 via the filling gas supply line 7.
Reference numeral 2A denotes a filling gas intake portion in the filling device 2, and reference numeral 9 denotes a check valve for preventing a backflow of hydrogen gas supplied to the measurement housing 1 side.

A dry gas pipe 4 for supplying dry gas (dry air or nitrogen) into the measurement housing 1 is detachably provided on the side surface of the measurement housing 1. The dry gas is supplied into the measurement housing 1 from a supply source (not shown) through the dry gas pipe 4, and the dry gas can be filled into the measurement housing 1.
Here, nitrogen or dry air can be used as the drying gas. Not only nitrogen or dry air, but the procurement cost is low, filling and discharging into the measurement housing 1 can be completed in a short time, and the gas is highly safe and has a molecular weight close to air (air) or nitrogen. Can be used. However, a gas whose molecular weight is significantly different from air (air) or nitrogen has a stable gas concentration or needs to be corrected by measuring the concentration.

Furthermore, a dew point meter 5 is detachably provided on the outer surface of the measurement housing 1, and appropriate humidity management can be performed in the measurement housing 1 based on the measurement result of the dew point meter 5. For example, when the dew point temperature of the dew point meter 5 reaches a predetermined temperature (for example, −20 ° C .: a dew point temperature at which it can be determined that the inside of the measurement housing 1 is sufficiently dry), the fuel gas (for example, −40 ° C. is cooled). Supply of hydrogen gas), the amount of condensation generated in the filling container 2, the filling gas supply pipe 7, the receptacle 6 and the like is reduced, and the influence of the amount of condensation on the weight measurement can be sufficiently reduced. I can do it.
Here, for example, if the dew point is lowered to −40 ° C. or lower, the dew amount becomes zero, but the difference between the dew point at a dew point of −40 ° C. or lower and the dew point at −20 ° C. is small. Therefore, it is realistic and economical to set about −20 ° C. to −25 ° C. as a dew point temperature that can be determined as necessary and sufficient dry.
In the illustrated embodiment, the dew point meter 5 is provided outside the measurement housing 1, but the dew point meter 5 may be provided in the measurement housing 1.

A gas discharge port 13 is provided on the upper surface of the measurement housing 1, and when the measurement housing 1 is filled with dry gas, air in the measurement housing 1 and other gas containing moisture are discharged to the outside of the measurement housing 1. Become an exit.
Furthermore, a filling gas discharge port 11 is provided on the upper surface of the measurement housing 1, and the charging gas discharge port 11 is connected to the filling container 2 by a filling gas discharge line 12.
When releasing hydrogen gas from the filling container 2, the hydrogen gas released from the filling container 2 passes through the filling gas discharge pipe 12 and is discharged from the filling gas discharge port 11 to the outside of the measurement housing 1. The main body housing 20 is provided with a gas release mechanism (not shown).

The filling gas supply line 7 is fixed to the bottom surface portion of the measurement housing 1 by a support member 14. The filling gas discharge pipe 12 is fixed to the outer wall portion of the measurement housing 1 by a support member 15. As a structure for fixing the filling gas supply pipe 7 and the filling gas discharge pipe 12 to the measurement housing 1 by the support member 14 and the support member 15, a conventionally known structure can be used.
The pedestal 8 on which the support member 14, the support member 15, and the filling container 2 are placed uses a heat insulating material having a low thermal conductivity, such as rubber or resin. Low temperature in the measurement housing 1 is conducted to the outer surface of the measurement housing 1 through the support member 14, the support member 15, and the pedestal 8, thereby preventing condensation on the outer surfaces of the measurement housing 1 and the scale 3 that are in contact with the atmosphere. Because.

Here, the inside of the measurement housing 1 has a semi-hermetic structure. The “semi-hermetic structure” means a structure that is not completely sealed but can be brought into a state almost similar to a sealed state.
By providing the measurement housing 1 with a semi-hermetic structure, if dry gas is supplied into the measurement housing 1 and the measurement housing 1 is held in a slightly pressurized state, air containing moisture is contained in the measurement housing 1. Can be prevented from entering.

In FIG. 1, a symbol CU indicates a control unit (control device) that performs control for eliminating an error due to buoyancy of gas (dry air, nitrogen) in the measurement housing 1.
The control unit CU is connected to the scale 3 through an input signal line ISL1, and is connected to the temperature sensor T through an input signal line ISL2. Here, the temperature sensor T is installed in the vicinity of the surface of the filling container 2.
The control unit CU is connected to the hydrogen filling device 40 via an input signal line ISL3, and the discharge pressure of the hydrogen filling device 40 is input via the input signal line ISL3. Here, the discharge pressure of the hydrogen gas filling device 40 is equal to the pressure in the hydrogen pipe 42 or the filling gas supply pipe 7 and is equal to the pressure in the filling container 2.

  Details of the control unit CU will be described with reference to the functional block diagram of FIG. In FIG. 2, the control unit CU has a pre-correction filling amount calculation block B1, an air density determination block B2, a solid volume determination block B3, a buoyancy fluctuation amount determination block B4, a filling amount correction value determination block B5, and a storage block B6. doing.

The pre-correction filling amount calculation block B1 has a function of calculating the hydrogen gas filling amount ΔW before correction based on the buoyancy of the gas (dry air, nitrogen) in the measurement housing 1. The pre-correction filling amount calculation block B1 is connected to the weight We data (measurement data of the balance 3) of the measurement housing 1 in a state before hydrogen gas filling and the hydrogen gas filling data through the first input signal line ISL1. Data of the weight Wc of the measurement housing 1 (measurement data of the balance 3) is acquired, and the filling amount ΔW of the hydrogen gas filled in the filling container 2 is calculated from the difference between the weight We and the weight Wc. The hydrogen gas filling amount ΔW is calculated by the following equation: ΔW = Wc−We
Further, the pre-correction filling amount calculation block B1 has a function of transmitting the calculation result of the hydrogen gas filling amount ΔW to the filling amount correction value determination block B5 and the storage block B6.

  The air density determination block B <b> 2 has a function of determining the gas density ρ at a predetermined temperature in the measurement housing 1. The air density determination block B2 uses the second input signal line ISL2 to measure the measurement data t1 (measurement data of the surface temperature of the filling container 2 before filling with hydrogen gas) t2 (measurement data of the filling container 2 before filling with hydrogen gas). Based on the characteristic data (air density ρ−temperature t characteristic data) indicating the relationship between the air density ρ and the temperature t acquired from the storage block B6. The density of the gas (the gas in the measurement housing 1) at the measured temperature is determined. Here, as the characteristic data indicating the relationship between the gas density ρ and the temperature t (air density ρ−temperature t characteristic data), conventionally known characteristic data can be used.

The density ρ determined in the air density determination block B2 will be described later with reference to FIG. In the illustrated embodiment, the gas densities at temperatures t1 ° C. and t2 ° C. are represented by symbols ρ (t1) and ρ (t2), respectively.
The densities ρ (t1) and ρ (t2) determined in the air density determination block B2 are transmitted to the buoyancy fluctuation amount determination block B4. The determined densities ρ (t1) and ρ (t2) are also transmitted to the storage block B6.

The solid volume determination block B3 includes a solid volume Qe in the measurement housing 1 in a state before filling with hydrogen gas (a volume affecting the fluctuation of the buoyancy: the filling container 2, the balance 3, the pedestal 8, the filling gas supply pipe in the housing 1). The volume occupied by the passage 7 and the like: the volume of the material constituting the measurement housing 1 is not included) and the solid volume Qc in the state after filling with hydrogen gas is calculated and determined.
At that time, the solid volume determination block B3 uses the third input signal line ISL3 to output the discharge pressure data Pe of the hydrogen gas filling device 40 from the hydrogen gas filling device 40 before the hydrogen gas filling and the state after the hydrogen gas filling. The discharge pressure data Pc of the hydrogen gas filling device 40 is acquired. As described above, since the discharge pressure of the hydrogen gas filling device 40 is equal to the pressure in the hydrogen pipe 42 or the filling gas supply pipeline 7 and equal to the pressure in the filling container 2, the discharge pressure data of the hydrogen gas filling device 40. This is because Pe and Pc can be regarded as pressures Pe and Pc in the filling container 2 before and after filling with hydrogen gas.

Here, the solid volume Q that affects the buoyancy fluctuation can be obtained as a function (for example, a linear function) of the pressure P in the filling container 2. The relationship between the pressure P in the filling container 2 and the solid volume Q is determined in advance at the time of manufacture of the calibration device and others, and the characteristics of the pressure P and the solid volume Q in the filling container 2 (pressure P-solid volume Q characteristic data) , Relational expressions, and charts) can be stored in the storage block B6.
The solid volume determination block B3 acquires the characteristic data of the pressure P and the solid volume Q in the filling container 2 from the storage block B6, and corresponds to the pressure Pe in the filling container 2 before hydrogen gas filling based on the characteristic data. It has a function of calculating and determining the solid volume Qe and the solid volume Qc corresponding to the pressure Pc in the filling container 2 after hydrogen gas filling.
In other words, the solid volumes Qe and Qc before and after filling with hydrogen gas are expressed as a function of the pressures Pe and Pc in the filling container 2 before and after filling with hydrogen gas. That is,
Qe = f (Pe),
Qc = f (Pc),
It is.

The solid volume Q that affects the buoyancy fluctuation includes not only the volume of the filling container 2 but also the volume of the balance 3, the pedestal 8, the filling gas supply line 7, etc. in the housing 1.
Here, in the amount of change (Qc−Qe) of the solid volume Q before and after hydrogen gas filling (pressures Pe and Pc in the filling container 2), the volume change amount of the filling container 2 occupies most. The volume Q1 of the filling container 2 increases, for example, linearly as the pressure rises (Q1 = kP + C1, C1 is a constant value), whereas the volumes Q2 of other devices maintain a substantially constant value. Therefore, the solid volume Q can also be expressed by, for example, the following formula: Q = Q1 + Q2 (Q is the solid volume, Q1 is the volume of the filling container 2, and Q2 is the volume of other equipment).
The solid volume determination block B3 has a function of transmitting the determined solid volume Q (Qe, Qc) to the buoyancy fluctuation amount determination block B4 and the storage block B6.

The buoyancy fluctuation amount determination block B4 is based on the solid volumes Qe and Qc before and after filling with hydrogen gas and the density ρ (t1) and ρ (t2) of the gas in the measurement housing 1 before and after filling with hydrogen gas. It has a function of calculating and determining a fluctuation amount (buoyancy fluctuation amount) ΔF before and after filling.
The buoyancy fluctuation amount determination block B4 obtains the data (Qe, Qc) of the solid volume Q before and after the hydrogen gas filling from the solid volume determination block B3, and the temperatures t1 ° C. and t2 before and after the hydrogen gas filling from the air density determination block B2. Data of density ρ (t1) and ρ (t2) corresponding to ° C. is acquired.

The buoyancy fluctuation amount determination block B4 includes solid volumes Qe and Qc before and after hydrogen gas filling (pressures Pe and Pc in the filling container 2) and densities ρ (t1) and ρ before and after hydrogen gas filling (temperatures t1 ° C. and t2 ° C.). The buoyancy fluctuation amount ΔF before and after hydrogen gas filling is calculated and determined from (t2).
As will be described later with reference to FIG. 4, since buoyancy F = solid volume Q × density ρ, buoyancy fluctuation amount ΔF is ΔF = Qc · ρ (t2) −Qe · ρ (t1)
It is calculated by the following formula.
Here, since the solid volumes Qe and Qc can be expressed by functions f (Pe) and f (Pc) of the pressures Pe and Pc in the filling container 2, respectively, the buoyancy fluctuation amount ΔF can be obtained by the following equation.
ΔF = f (Pc) · ρ (t2) −f (Pe) · ρ (t1)
The buoyancy fluctuation amount determination block B4 has a function of transmitting the determined buoyancy fluctuation amount ΔF to the filling amount correction value determination block B5 and the storage block B6.

The filling amount correction value determination block B5 has a function of correcting the hydrogen gas filling amount based on the buoyancy fluctuation amount ΔF before and after hydrogen gas filling, and calculating and determining the corrected hydrogen gas filling amount ΔWt (filling amount correction value). Have.
In other words, the filling amount correction value determination block B5 acquires the data of the hydrogen gas filling amount ΔW (= Wc−We) from the pre-correction filling amount calculation block B1, and the hydrogen gas from the buoyancy fluctuation amount determination block B4. Data of the buoyancy fluctuation amount ΔF before and after filling is acquired, and a filling amount correction value ΔWt (filling amount after correction) is calculated and determined.
As will be described later with reference to FIG. 4, the filling amount correction value ΔWt is obtained by the following equation.
ΔWt = Wc−We−ΔF
= Wc−We− {Qc · ρ (t2) −Qe · ρ (t1)}
= Wc-We- {f (Pc) .rho (t2) -f (Pe) .rho (t1)}
The filling amount correction value determination block B5 has a function of transmitting the determined filling amount correction value ΔWt to the display means D (display) outside the control unit CU and the storage block B6.

The filling amount correction value ΔWt is displayed on the display means D as a calibration result and stored in the storage block B6.
In the memory block B6, characteristic data indicating the relationship between the air density ρ and the temperature t (air density ρ−temperature t characteristic data), characteristic data indicating the relationship between the pressure P in the filling container 2 and the solid volume Q (pressure) P-solid volume Q characteristic data), determination results (ΔW, ρ, Q, ΔF, ΔW) of the functional blocks B1 to B5 and the like are stored and referred to by the functional blocks B1 to B5 as necessary.
Characteristic data (pressure P−solid volume Q characteristic data) indicating the relationship between the pressure P and the solid volume Q in the filling container 2 is, for example, at the time of manufacturing a calibration device or other pressure P and solid volume in the filling container 2 in advance. When the relationship with Q is measured, it is input or recorded in the storage block B6.

Next, a calibration procedure using the calibration apparatus 100 of FIG. 1 will be described with reference to FIG.
In the calibration flowchart of FIG. 3, in step S <b> 1, the weight of the measurement housing 1 in the state before filling with hydrogen gas is first measured by the scale 3 in a state where the dry gas pipe 4 and the filling nozzle 41 are not connected. .
Then, the dry gas pipe 4 and the filling nozzle 41 are connected to the measurement housing 1 (connection work), the air in the measurement housing 1 and other gas containing moisture are discharged (scavenging work), and the hydrogen filling device 40 ( The filling container 2 is filled with hydrogen gas from the calibration target) (filling operation), and then the dry gas pipe 4 and the filling nozzle 41 are disconnected (disconnection operation).

In the connection operation in step S1, the dry gas pipe 4 is connected to one side surface of the measurement housing 1. Then, the filling nozzle 41 of the hydrogen filling device 40 is connected to the receptacle 6 provided on the side surface of the measurement housing 1.
In the scavenging operation, dry gas is supplied and filled into the measurement housing 1 from a dry gas supply source (not shown) via the dry gas pipe 4. By filling the measurement housing 1 with the dry gas, a gas containing moisture such as air existing in the measurement housing 1 is discharged from the gas discharge port 13 to the outside of the measurement housing 1.

  The scavenging operation is performed while monitoring the measured value of the dew point meter 5 as needed. As scavenging progresses, the dew point temperature gradually decreases, and the humidity in the measurement housing 1 decreases. When the dew point temperature reaches a predetermined temperature (for example, −20 ° C.), it is determined that the inside of the measurement housing 1 is sufficiently dry.

As described above, in the scavenging operation in step S1, when the dew point temperature reaches a predetermined temperature and it is determined that the inside of the measurement housing 1 is sufficiently dry, the filling operation in step S1 is performed.
The filling of hydrogen gas is performed until it is determined by a flow meter (not shown) of the hydrogen filling device 40 that a predetermined amount of hydrogen gas has been supplied.
After completion of the filling operation, the connection release operation in step S1 is performed. In the connection release operation, the connection between the dry gas pipe 4 and the filling nozzle 41 is released.
When step S1 ends, the process proceeds to step S2.

In step S <b> 2, the weight (the weight of the measurement housing 1 after filling with hydrogen gas) when the filling container 2 in the measurement housing 1 is filled with hydrogen gas from the hydrogen filling device 40 is measured by the balance 3.
Then, from the measurement result of the weight of the measurement housing 1 before filling with hydrogen gas (step S1) and the measurement result of the weight of the measurement housing 1 after filling with hydrogen gas (step S2), the weight of the hydrogen gas filled in the filling container 2 is calculated. Calculate the hydrogen gas filling amount.
The hydrogen filling device 40 is calibrated by comparing the calculated filling amount with the filling amount determined based on the flow meter of the hydrogen filling device 40 to be calibrated. When step S2 ends, the process proceeds to step S3.

In step S <b> 3, control (or procedure) is performed on the measurement result of the weight of the measurement housing 1 to eliminate an error due to the buoyancy of the gas (dry air, nitrogen) in the measurement housing 1. This control will be described later with reference to FIG.
In step S3, the weight value of hydrogen gas, the filling amount of hydrogen gas calculated from the weight of the measurement housing 1 before and after filling, and the result of calibration are displayed on a display device (display or the like) not shown.
Further, the hydrogen gas filling amount or the weight of the filled hydrogen gas, which is the measurement result, together with the identification number (for example, product number) of the hydrogen filling device 40 to be calibrated, the calibration date and time, etc. Save it to a storage device of a computer that does not. Then, the calibration procedure is terminated.

Although not explicitly shown in FIG. 3, when the calibration apparatus 100 continues to calibrate another target apparatus, after step S <b> 3, the hydrogen gas filled in the filling container 2 is filled with the filling gas discharge pipe 12 and filling. The gas is discharged to the outside of the measurement housing 1 through the gas discharge port 11.
When the calibration of the separate hydrogen filling apparatuses 40 is continuously performed, the process returns to “START” in FIG. 3 and the operations of steps S1 to S3 are executed.
The release of the hydrogen gas filled in the filling container 2 can also be performed in the “balance reset” of step S1 in the calibration of the next hydrogen filling apparatus 40.

As described above with reference to FIG. 3, in the illustrated embodiment, the control (or procedure) for eliminating the error due to the buoyancy of the gas (dry air, nitrogen) in the measurement housing 1 is executed.
The control (or procedure) for eliminating the error due to the buoyancy of the gas in the measurement housing 1 will be described mainly with reference to FIG. 4 and also with reference to FIGS.

  According to the inventor's research and experiment, the buoyancy due to the gas (dry air, nitrogen) in the measurement housing 1 is different from the buoyancy of the gas acting on the entire volume of the measurement housing 1 and is accommodated in the measurement housing 1. It has been found that the buoyancy of the gas acting on the devices (filling container 2, scale 3, pedestal 8, filling gas supply pipe line 7, etc.). In other words, the buoyancy caused by the gas (dry air, nitrogen) in the measurement housing 1 acts on the total volume Q (volume of solids other than the measurement housing 1) of the devices in which the gas is accommodated in the measurement housing 1. Buoyancy.

This is because the buoyancy of the gas acting on the volume AQ obtained by removing the solid volume Q from the volume of the measurement housing 1 is the same before and after the hydrogen gas filling, so that the buoyancy of the gas acting on the volume AQ is offset. It is estimated that.
In other words, the buoyancy of the gas acting on the volume AQ obtained by removing the solid volume Q from the volume of the measurement housing 1 is offset when the weight of the measurement housing 1 before and after hydrogen gas filling is measured to obtain the weight difference. This does not affect the accuracy of the hydrogen gas filling amount.

  As described above, it is the solid volume Q (such as the filling container 2, the scale 3, the pedestal 8, and the filling gas supply line 7 that are accommodated in the measurement housing 1 of the calibration device 100) that is involved in fluctuations in buoyancy. (Total volume: solid volume other than the measurement housing 1). The solid volume Q is obtained as a function of the pressure P in the filling container 2 (equal to the discharge pressure of the gas filling device 40, the pressure of the hydrogen pipe 42 or the filling gas supply line 7), and the pressure P in the filling container 2 A function (including pressure P-solid volume Q characteristic data, relational expressions, and charts) with the solid volume Q is determined in advance before calibration. Note that it is also possible to determine a function (including relational expressions and charts) between the pressure P in the filling container 2 and the solid volume Q at the time of calibration.

In step S11 and subsequent steps in FIG. 4, when the buoyancy of the gas (dry air, nitrogen) in the measurement housing 1 is obtained, characteristic data (air density ρ) indicating the relationship between the air density ρ and the temperature t from the temperature of the gas. -Temperature t-characteristic data: known data) is used to determine the density. Here, the temperature of the gas in the measurement housing 1 greatly changes depending on the time and the measurement position.
On the other hand, in steps S11 and S12 of FIG. 4, the temperature of the gas is measured by the temperature sensor T installed on the surface of the filling container 2, and the density ρ of the gas is determined from the measured temperature of the gas. . In other words, in the illustrated embodiment, the gas temperature on the surface of the filling container 2 is adopted as the representative value of the temperature of the gas in the measurement housing 1, and the gas density ρ is determined from the representative value.

According to the inventor's research and experiment, the gas density ρ determined by a complicated calculation in consideration of the heat density, the radiation, and the time lapse as a result of determining the gas density ρ with the temperature of the gas on the surface of the filled container 2 as a representative value. Has been confirmed to match with high accuracy. Therefore, if the gas density ρ is determined with the temperature of the gas on the surface of the filled container 2 as a representative value, the influence of buoyancy can be achieved with the same degree of accuracy without performing complex calculations taking heat transfer, radiation, and time passage into account. Can be calculated and calibrated.
Further, by determining the gas density ρ and the solid volume Q, the buoyancy due to the gas in the measurement housing 1 regardless of the change in the gas temperature depending on the time and the measurement position and the change in the pressure in the filling container 2 before and after the hydrogen gas filling. The error due to fluctuations in buoyancy can be resolved.

In step S11 of FIG. 4, the weight We of the measurement housing 1 before hydrogen gas filling and the representative temperature t1 are measured. The representative temperature t1 is the temperature of the gas on the surface of the filling container 2 as described above. Then, the gas density ρ (t1) corresponding to the representative temperature t1 is obtained from characteristic data indicating the relationship between the air density ρ and the temperature t (air density ρ−temperature t characteristic data: publicly known data can be used).
In step 11, the pressure Pe and the solid volume Qe in the filling container 2 before hydrogen gas filling are obtained. As described above, since the pressure Pe in the filling container 2 can be considered to be equal to the discharge pressure of the hydrogen gas filling device 40, the pressure Pe in the filling container 2 is obtained by measuring the discharge pressure of the hydrogen gas filling device 40. You can ask. The solid volume Qe corresponding to the pressure Pe in the filling container 2 is characteristic data measured or determined in advance, that is, characteristic data indicating the relationship between the pressure P in the filling container 2 and the solid volume Q (pressure P-solid). (Volume Q characteristic data) The solid volume Qe before filling with hydrogen gas can be expressed as Qe = f (Pe).
Thereby, in step S11, weight We of measurement housing 1 before filling, gas density rho (t1), and solid volume Qe are determined. Then, the process proceeds to step S12.

In step S12, the weight Wc and the representative temperature t2 of the measurement housing 1 after hydrogen gas filling are measured. Then, the gas density ρ (t2) corresponding to the representative temperature t2 is obtained from the characteristic data indicating the relationship between the air density ρ and the temperature t (air density ρ−temperature t characteristic data).
In step 12, the pressure Pc and the solid volume Qc in the filling container 2 after hydrogen gas filling are obtained. As described in step S11, the pressure Pc in the filling container 2 is obtained by measuring the discharge pressure of the hydrogen gas filling device 40, and shows the relationship between the pressure P in the filling container 2 and the solid volume Q. From the characteristic data (pressure P-solid volume Q characteristic data), the solid volume Qc corresponding to the pressure Pc is obtained. The solid volume Qc after filling with hydrogen gas can be expressed as Qc = f (Pc).
Thereby, in step S12, the weight Wc, the gas density ρ (t2), and the solid volume Qc of the measurement housing 1 after filling are determined.
Then, the process proceeds to step S13.

In the next step S13, a hydrogen gas filling amount ΔW before correction by gas buoyancy is calculated. The hydrogen gas filling amount ΔW is obtained by the following equation: ΔW = Wc−We based on the weights We and Wc of the measurement housing 1 before and after the hydrogen gas filling.
In step S13, the amount of change ΔF in gas buoyancy before and after hydrogen gas filling is calculated. The fluctuation amount ΔF of the buoyancy of the gas can be obtained from the following equation using the solid volumes Qe and Qc and the gas densities ρ (t1) and ρ (t2) before and after the hydrogen gas filling determined in steps S11 and S12.
ΔF = Qc · ρ (t2) −Qe · ρ (t1)
= F (Pc) .rho (t2) -f (Pe) .rho (t1)
Thereby, in step S13, the hydrogen gas filling amount ΔW before correction and the gas buoyancy fluctuation amount ΔF are calculated.
Then, the process proceeds to step S14.

In step S14, the hydrogen gas filling amount ΔWt after correction by gas buoyancy is calculated. The hydrogen gas filling amount ΔWt after correction by gas buoyancy is obtained by the following equation based on the calculation result of step S13.
ΔWt = ΔW−ΔF
= Wc−We− {Qc · ρ (t2) −Qe · ρ (t1)}
= Wc-We- {f (Pc) .rho (t2) -f (Pe) .rho (t1)}
Then, the process proceeds to step S15.

In step S15, the hydrogen filling apparatus 40 is calibrated as described in step S2 of FIG. 3 using the corrected filling amount ΔWt.
As a result, in the illustrated embodiment, errors due to the buoyancy of the gas (dry air, nitrogen) in the measurement housing 1 can be eliminated. And control is complete | finished.

According to the illustrated embodiment, even if the volume of the filling container 2 fluctuates before and after filling with fuel gas (for example, hydrogen), the solid volume Q of the device accommodated in the measurement housing 1 is determined, and the fuel gas By determining fluctuations in the buoyancy of the gas (dry air, nitrogen) in the measurement housing 1 before and after charging, and taking such fluctuations into account, calibration errors due to fluctuations in buoyancy are eliminated.
Therefore, it is possible to accurately measure the weight of the filled hydrogen gas, thereby improving the calibration accuracy of the hydrogen gas filling apparatus 40.

Here, the relationship between the pressure of the filling container 2 accommodated in the measurement housing 1, the volume of the solid volume Q, and the pressure (equal to the discharge pressure of the fuel gas filling device 40) (which is often a linear relationship). Is obtained in advance, and the solid volume Q can be obtained by obtaining the pressure of the filling container 2.
In the illustrated embodiment, when the fluctuation of buoyancy due to the gas in the measurement housing 1 is eliminated, the devices (the filling container 2, the balance 3, the pedestal 8, the filling gas supply line 7, etc.) accommodated in the measurement housing 1 are used. : The gas acting on the volume AQ excluding the solid volume Q from the volume of the measurement housing 1 in consideration of only the buoyancy acting on the solid volume Q, which is the sum of the volumes of the material constituting the measurement housing 1 The buoyancy of is not considered. That is, the calculation of the influence due to buoyancy is performed only for the solid volume Q.
The variation in buoyancy due to the gas in the measurement housing 1 determined in this manner is well suited to the experiment results of the inventors.

And according to embodiment of illustration, when calculating | requiring the buoyancy of the gas (dry air, nitrogen) in the measurement housing 1, the temperature of the gas in the filling container 2 surface is calculated | required, and the said temperature is the temperature of the gas in the measurement housing 1. Since the gas density ρ is determined as a representative value, the buoyancy due to the gas in the measurement housing 1 can be determined regardless of changes in the gas temperature depending on the time and measurement position, and errors due to fluctuations in buoyancy can be eliminated. .
According to the inventor's research and experiment, the gas density ρ determined by using the temperature of the gas on the surface of the filled container 2 (as a representative value) was obtained by a complicated calculation considering heat transfer, radiation, and time passage. It was confirmed that the gas density ρ coincided with high accuracy. That is, according to the illustrated embodiment, the buoyancy of the gas (dry air, nitrogen) in the measurement housing 1 can be obtained without the need to perform complicated calculations in consideration of heat transfer, radiation, and time.

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, although the illustrated embodiment is described as a calibration device for a hydrogen filling device, the present invention can also be applied to a calibration device for a CNG filling device.
In the illustrated embodiment, the discharge pressure of the hydrogen gas filling device 40 is measured in order to obtain the pressure in the filling container 2, but a pressure gauge is disposed in the filling gas supply pipe 7 or the hydrogen pipe 42, and the pressure is measured. It is also possible to obtain the pressure in the filling container 2 by measuring the measured value of the meter.

DESCRIPTION OF SYMBOLS 1 ... Measurement housing 2 ... Filling container 3 ... Scale 4. ... Dry gas line 5 ... Dew point meter 6 ... Receptacle (hydrogen receiving port)
7 ... Filling gas supply line 8 ... Base 9 ... Check valve 11 ... Filling gas discharge port 12 ... Filling gas discharge line 13 ... Gas discharge port 14, 15 ... -Support member 20 ... body housing 20A ... moving means (wheels, etc.)
40 ... Hydrogen filling device 41 ... Filling nozzle 42 ... Hydrogen piping 100 ... Calibration device B1 ... Filling amount calculation block B2 before correction ... Air density determination block B3 ... Solid volume Determination block B4 ... Buoyancy fluctuation amount determination block B5 ... Fill amount correction value determination block B6 ... Storage block CU ... Control unit (control device)
D: Display (display means)
T ... Temperature sensor

Claims (4)

A filling container to which high-pressure fuel gas is supplied from the outside in the measurement housing, a scale for measuring the weight of the fuel gas supplied to the filling container, and a control device are provided,
The control device has a function of eliminating an error caused by fluctuation of the buoyancy of the gas in the measurement housing before and after filling with the fuel gas based on the change in the volume of the filling container in the measurement housing. apparatus.   The control device is accommodated in the measurement housing in order to eliminate an error caused by fluctuations in the buoyancy of the gas in the measurement housing before and after filling with the fuel gas based on the change in the volume of the filling container in the measurement housing. 2. The calibration apparatus according to claim 1, wherein the calibration apparatus has a function of calculating only a buoyancy acting on a total sum of the volumes of the devices, and a function of determining the volume of the filling container based on the pressure of the filling container in the measurement housing. In the calibration method of the fuel gas filling device using the calibration device according to claim 1,
Measuring the weight of the measurement housing before and after fuel gas filling;
A process for eliminating an error caused by fluctuation of the buoyancy of the gas in the measurement housing before and after the fuel gas filling based on a change in the volume of the filling container in the measurement housing due to a difference in weight of the measurement housing before and after the fuel gas filling. A calibration method characterized by comprising:   In the process of eliminating the error due to the fluctuation of the buoyancy of the gas in the measurement housing before and after the fuel gas filling based on the change in the volume of the filling container in the measurement housing due to the difference in the weight of the measurement housing before and after the fuel gas filling The calculation of the buoyancy of the gas in the measurement housing is performed only for the buoyancy that affects the total volume of the devices accommodated in the measurement housing, and based on the pressure of the filling container in the measurement housing, The calibration method according to claim 3, wherein the volume is determined.

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