JP2003065495A - Mixed gas charging method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mixed gas charging method and its device capable of charging a mixed gas with a comparatively low mixing ratio of a gas of low molecular weight such as hydrogen and helium, with high accuracy. SOLUTION: When the mixed gas composed of a plurality of gas components is charged to a container, a predetermined amount of the gas of low molecular weight among the gas components is charged by a pressure charging method, and then the gas of comparatively high molecular weight is charged by a mass charging method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for filling a mixed gas into a container and a mixed gas filling device used in this filling method.

[0002]

2. Description of the Related Art Many mixed gases are used in the fields of industrial gas and medical gas. Examples of industrial mixed gases include Ar-CO2, Ar-O2, Ar-H2, and the like.
These are used as a shield gas for welding. As a mixed gas for medical use, there is a mixed gas such as N2-O2. It is used as conditioned artificial air. These mixed gases are filled in a gas container and supplied to the destination. As a method for filling the mixed gas into the container, there are a pressure filling method and a mass filling method. In general, high pressure gas is 3
It is filled to have a pressure of 14.7 MPa at 5 ° C.

As shown in FIG. 2, a filling device 50 can be used in the filling method by the pressure filling method. Reference numerals 52 and 62 represent check valves. First, the valve 51 of the A gas supply pipeline TA and the valve 61 of the B gas supply pipeline TB are closed,
The valve 55 and the blow valve 54 of the common supply pipeline TAB are opened, and the supply pipelines TA, TB, TAB and the container to be filled (not shown) are evacuated by the blow valve 54. Then, the blow valve 54 is closed and the valve 51 is opened to supply A gas to the container to be filled,
While monitoring the pressure of the A gas by the pressure gauge 53, the A gas is filled into the container until the gas pressure reaches a value corresponding to the desired mixing ratio.

Subsequently, the valve 51 is closed to stop the supply of A gas, the valve 61 is opened, and B gas is introduced into the container to be filled. While monitoring the pressure of the B gas with the pressure gauge 53, the B gas is supplied to the container until the gas pressure reaches a value corresponding to the desired mixing ratio. When the gas pressure reaches a predetermined value, the valves 55 and 61 are closed to stop the supply of B gas.
By the above operation, a container filled with a mixed gas having a desired mixing ratio is obtained.

However, in the filling method by this pressure filling method, the gas temperature may rise due to the compression of the gas as the gas is filled, and the gas pressure in the container may rise.
Further, the gas temperature may change due to the outside air temperature, and the gas pressure may change. In such a case, since the gas pressure changes depending on the temperature, it becomes difficult to accurately set the mixing ratio of the A gas and the B gas to a desired value.

As shown in FIG. 3, in the filling method by the mass filling method, the common supply pipe TAB of the filling device shown in FIG. 2 is used.
To the reference container 6 via the reference conduit Tr.
A filling device 60 with 5 connected can be used.
The reference container 65 is placed on the measuring device 66 so that the mass of gas filled in the container 65 can be measured. In some cases, the reference container is not used and the container to be filled is placed on the measuring instrument. In this method, the valve 51 of the A gas supply pipe TA and the valve 61 of the B gas supply pipe TB are closed, the valve 55 of the common supply pipe TAB and the valve 63 of the reference pipe Tr are opened, and the pipe TA , TB, TAB,
Tr, the container 65, and a container to be filled (not shown),
Evacuate through the blow valves 54, 64.

Then, the blow valves 54 and 64 are closed, and the valve 5
1 is opened and A gas is supplied to a container (not shown) to be filled. At this time, the A gas is also supplied to the reference container 65. The change in mass of the reference container 65 is measured by the measuring instrument 66
The gas A is supplied until the mass of the gas in the container 65 reaches a value corresponding to the desired mixing ratio while monitoring. Then, when the mass of the A gas in the reference container 65 reaches a predetermined value, the valve 51 is closed and the supply of the A gas is stopped.

Next, the valve 61 is opened and the B gas is supplied to the container to be filled and the reference container 65 via the supply lines TB, TAB, Tr. At this time, the metering device 66 measures the B gas filling mass of the reference container 65, and supplies the B gas until the mass reaches a value corresponding to the mixing ratio of the mixed gas to be filled. When the mass of B gas reaches a predetermined value, the valve 61 is closed to stop the supply of B gas. By the above operation, a container filled with a mixed gas having a desired mixing ratio is obtained. In this method, the gas filling is performed while measuring the gas filling mass, so that the filling can be performed without being affected by the pressure fluctuation due to the temperature rise accompanying the pressure rise during the filling.

However, the mass of the empty high-pressure gas container to be weighed is in the order of kg, whereas the mass of the gas to be filled is in the order of tens of g. When filling a small gas, it may be difficult to accurately measure the filling gas. In particular, in the case of a mixed gas having a small mixing ratio, such as a mixed gas having an H2 concentration of 1%, it may be below the measurement limit of measurement, and it is not suitable for the filling method by the mass filling method. For example, when a 47 L manganese steel high-pressure gas container with an empty mass of 50 kg is filled with a mixed gas containing 1% H2 at 14.7 MPa, the H2 mass to be filled is only 6.3 g. The accuracy of weighing is 1 / 30,000 of the full scale for high accuracy on the market, and the minimum scale is 3g for a weighing machine with a rated (maximum) weight of 100kg, so high-precision filling is possible. It is difficult.

[0010]

As described above, in the conventional mixed gas filling method, since the mixed gas is filled based on the gas pressure and the gas mass that cannot obtain the measurement accuracy, the gas filling amount is not a little error. Was occurring. The present invention has been made in view of the above circumstances, and includes hydrogen (H2) and helium (He).
It is an object of the present invention to provide a mixed gas filling method and a device for accurately filling a mixed gas having a relatively small mixing ratio of gas having a small molecular weight.

[0011]

According to the method for filling mixed gas of the present invention, when filling a mixed gas composed of a plurality of gas components into a container,
It is characterized in that after a predetermined amount is filled by the pressure filling method, a gas having a relatively large molecular weight is filled by the mass filling method. The mixed gas filling apparatus of the present invention comprises a first gas supply system for supplying a gas having a small molecular weight, a second gas supply system for supplying a gas having a relatively large molecular weight, and a first gas supply system for supplying the gas having a relatively large molecular weight. A common supply system for supplying gas to the container, a pressure detection means for detecting the gas pressure is provided in the first supply system, and a mass detection means for detecting the gas mass is provided in the second supply system or the common gas supply system. It is characterized by being provided. At least one of the first gas supply system and the second gas supply system can be configured to include a plurality of systems for supplying gas components.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a mixed gas filling apparatus of the present invention will be described with reference to FIG. The mixed gas filling device 1 shown in FIG. 1 includes a gas supply system 2 that supplies gases from four gas sources Ga, Gb, Gc, and Gd to a container Z to be filled, and a reference system 3 that measures the mass of each gas. It is equipped with. The gas supply system 2 is a hydrogen gas having a small molecular weight,
A first gas supply system 4 for supplying helium gas and the like, a second gas supply system 5 for supplying oxygen gas, argon gas, nitrogen gas, carbon dioxide gas and the like having relatively large molecular weights, and these supply systems 4, 5 A common gas supply system 6 for supplying gas together to the filling target container Z is provided.

The first gas supply system 4 includes a gas source Ga such as a gas cylinder, a supply valve 11, a pressure reducing valve 12, a needle valve 13 for adjusting the flow rate, a check valve 14, and a first pressure gauge ( A pressure detecting means) 15 and a safety valve 16 are provided. Second
The gas supply system 5 includes three gas supply systems 5a, 5b, 5c.
Is equipped with. The gas supply system 5a includes a gas source Gb such as a gas cylinder, a supply valve 21, and a check valve 24. The gas supply system 5b includes a gas source Gc and a supply valve 31.
And a check valve 34. The gas supply system 5c is
A gas source Gd, a supply valve 41, and a check valve 44 are provided.

The common gas supply system 6 is provided with a second pressure gauge (pressure detecting means) 17, a safety valve 18, a thermometer 20, and a blow valve 19. The thermometer 20 has a temperature correction means for correcting the detection values of the pressure gauges 15 and 17 based on the gas temperature, that is, the detected gas pressure is converted into a gas pressure at a predetermined temperature (for example, 35 ° C.). What can be done is suitable.

The reference system 3 is for measuring and measuring the mass of gas, and is connected to the common gas supply system 6. The reference system 3 is a reference container 36.
And a load cell 38 (mass detecting means) for measuring its mass. The load cell 38 includes a pressure-electricity conversion mechanism that generates electricity by a load, and can measure the mass of gas in the reference container 36. The load cell 38 can set the minimum scale according to the molecular weight of the component gas to be filled, the mixing ratio thereof, and the mixing accuracy. In the present invention, the reference system 3 may be connected to the second gas supply system 5. The connection position of the reference system 3 is the check valve 2
It is preferable to use at least one secondary side of 4, 34, and 44.

Next, an example of a method of filling the mixed gas using the filling device will be described with reference to FIG. The mixed gas filled in the container was a hydrogen-argon mixed gas containing 1% by volume of hydrogen. The specifications of each device arranged in the used mixed gas filling device 1 are as follows. <Device specifications> -Pressure gauge 15: Full scale 1MPa, 0.5 class (minimum scale 0.01MPa) -Pressure gauge 17: Full scale 25MPa, 0.5 class (minimum scale 0.2MPa) -Reference container 36: 3 .4 liter container (material:
Manganese steel), empty mass 7 kg ・ Load cell 38: minimum weighing unit 0.2 g The load cell 38 is a reference container (cylinder) 3 in advance.
The mass obtained by subtracting the mass of 6, that is, the mass of only the target gas was set to be displayed.

Component gas source Ga of the first gas supply system 4: Hydrogen (H2) gas cylinder Component gas source Gb of the second gas supply system 5: Argon (Ar)
Liquid Argon Tank with Evaporator as Source, Filling Container Z: Collective container with 10 47 liter cylinders connected. The component gas sources Gc and Gd of the second gas supply system 5 were not used here, and the supply valves 31 and 41 arranged in the pipelines Tc and Td connected to them were closed.

First, the supply valve 11 of the first gas supply system 4 and the supply valve 21 of the second gas supply system 5 are closed, and the valve 25,
35, the container valve Za of the container Z to be filled, the container valve 36a of the reference container 36, and the like are opened. Then blow valve 1
Opening 9 and 37, the conduit Ta of the first gas supply system 4, the conduit Tb of the second gas supply system 5, and the conduit Ta of the common gas supply system 6
d, the pipe Tr of the reference system 3, the filling target container Z, and the gas in the reference container 36 are discharged. Then
One of the blow valves 19 and 37 is closed, and each of the pipelines Ta and Tb is connected to the other blow valve by a vacuum pump (not shown).
The insides of Tad, Tr, and the containers Z and 36 were evacuated. Then, the blow valves 19 and 37 were closed to shut off the entire system from the atmosphere.

Next, the hydrogen gas supply valve 11 is opened, and while the pressure of the hydrogen gas is being confirmed by the pressure gauge 15, the secondary pressure of the pressure reducing valve 12 (pressure on the downstream side in the gas supply direction) is 0.15.
The gas was supplied so that the pressure would be MPa. The supply of hydrogen gas was stopped when the hydrogen gas was filled until the pressures in the reference container 36, the filling target container Z, and the respective pipelines became 0.15 MPa. At this time, load cell 3
The gas filling mass of the container 36 measured by 8 is 0.4 g
Became. According to the calculation, the amount of hydrogen (H2) filled in the reference container (3.4 liter) 36 is as follows. 3.4 x 150 x 1/100 x 2.0 / 22.4 = 0.46
g Further, since the filling pressure of hydrogen gas was as low as 0.15 MPa, the temperature of hydrogen gas hardly increased during filling.

Then, the supply valve 11 of the pipe Ta is closed,
The supply valve 21 of the pipe line Tb was opened, and the container Z was filled with argon gas until the amount of gas filled into the container 36 reached a mass of 90.4 g corresponding to an argon concentration of the mixed gas of 99% by volume. At this time, the gas temperature rose due to the compression of the gas, but since the gas filling amount was controlled by mass, it was possible to fill a predetermined amount without any particular problems. The above-mentioned argon filling mass of 90.4 g is calculated as follows: 3.4 × 150 × 99/100 × 39.95 / 22.4 =
It was calculated based on 900.5 g. At this time, the gas pressure measured by the pressure gauge 17 becomes 1 as the temperature rises due to the increase of the filling pressure.
Although it increased to 5.1 MPa, it decreased to 14.7 MPa at 35 ° C. as the temperature decreased. Although the measurement value of the load cell 38 is reset once after filling with hydrogen in the above embodiment, the argon gas may be filled in the container Z as it is without resetting.

In the above-mentioned filling method, the filling management of the hydrogen gas is performed while monitoring the hydrogen gas pressure by the pressure gauge 15, and then the filling control of the argon gas is performed.
In the present invention, the pressure gauge 15 and the load cell 38 are provided with output setting contacts, and the hydrogen filling pressure is input and set in advance in the pressure gauge 15. The filling operation can be automated by inputting and setting the filling amount of argon into the load cell 38. That is, when the value of the pressure gauge 15 reaches the set value, the supply valve 11 of the hydrogen gas supply pipe Ta is automatically closed,
Subsequently, the supply valve 21 of the argon gas supply pipe line Tb is opened so that the filling of the argon gas is started. Then, when the measured value of the load cell 38 reaches the set value,
The valve 21 is closed so that the argon gas supply is stopped. As a result, the desired mixed gas can be filled by an automated operation.

In the filling method of this embodiment, hydrogen gas having a small molecular weight is first filled by the pressure filling method, and then argon gas having a relatively large molecular weight is filled by the mass filling method. It is not affected by pressure fluctuation due to temperature rise due to pressure rise.
Therefore, the mixed gas can be filled with high accuracy and reproducibility. The configuration of the filling device can be obtained by attaching the first gas supply system 4 adopting the pressure filling method to the existing filling device adopting the conventional mass filling method. Therefore, the equipment cost can be kept low. In particular, when the gas supply pressure by the first gas supply system 4 can be set to less than 1 MPa, the attached equipment is out of the scope of the high pressure gas safety law, so that the equipment cost can be further reduced.

The pressure-filling method, which is a conventional filling method, can be similarly performed by using the mixed gas filling apparatus of the present invention. Hereinafter, description will be given with reference to FIG. Prior to filling the mixed gas into the container Z to be filled, the pipe lines Ta, T
The supply valves 11, 21, 31, 41 of b, Tc, Td, the blow valve 19 of the conduit Tad, and the blow valve 37 of the conduit Tr are closed, and the valves 35, 25 and the container valves Za, 36a are respectively closed. It was open.

Then, the blow valves 19 and 37 are opened,
After exhausting the gas in the pipe lines Ta, Tb, Tad, Tr and the containers Z, 36, one of the blow valves 19, 37 is closed and a vacuum pump (not shown) is provided through the other blow valve.
Inside the pipelines Ta, Tb, Tad, Tr, and containers Z, 3
The inside of 6 was evacuated. Then, the blow valves 19 and 37 were closed to shut off the entire system from the atmosphere.

Next, the hydrogen gas supply valve 11 is opened, and while checking the gas pressure with the pressure gauge 15, hydrogen gas is supplied so that the secondary pressure (downstream pressure) of the pressure reducing valve 12 becomes 0.15 MPa. did. The supply of hydrogen gas was stopped at the time when the hydrogen gas was supplied to the inside of the reference container 36, the container Z to be filled, and the inside of each pipeline until the set pressure reached 0.15 MPa. At this time, the gas filling mass of the container 36 measured by the load cell 38 was 0.4 g. According to calculations, the reference container (3.4 liters) 36
The amount of hydrogen (H2) charged in the reactor is as follows. 3.4 x 150 x 1/100 x 2.0 / 22.4 = 0.46
g Further, since the filling pressure of hydrogen gas was as low as 0.15 MPa, the temperature of hydrogen gas hardly increased during filling.

Then, the supply valve 11 of the pipe Ta is closed,
The measured value of the load cell 38 is reset to 0, and the pipeline T
While the supply valve 21 of b is opened and the gas pressure is monitored by the pressure gauge 17 provided in the pipe Tad, this pressure is 14.
Argon gas was supplied until the pressure reached 7 MPa. At this time, it was possible to accurately fill the mixed gas containing 1% by volume of hydrogen by slowly filling the argon gas so that the gas temperature did not rise due to the compression of the gas.

In the present invention, it is important that the gas having a small molecular weight is first accurately and accurately filled. The empty mass of the reference container 36 having a capacity of 3.4 liters is 7 kg, and the full scale of the general-purpose load cell 38 is 12 k.
g, the minimum scale is 0.2 g. On the other hand, the empty body mass of the container Z to be filled having a capacity of 47 liters is 50 kg, the full scale of a general-purpose load cell is 100 kg, and the minimum scale is 3.0 g. Therefore, the mixed gas filling method of the present invention is effective when the mixing ratio of the gas having a small molecular weight is 10% by volume or less, and particularly when the gas having a small molecular weight is hydrogen, the content rate is 5% by volume. Effective when: When the hydrogen content is more than 5% by volume, the required filling amount is 10 times or more of the minimum scale, and the mass filling method using the load cell can be used.

Similarly, when the gas having a small molecular weight is helium, the required filling amount is 10 times or more of the minimum scale for a mixed gas having a helium content of more than 3% by volume. Correspondence becomes possible. Therefore, the filling method of the present invention is particularly effective when the helium content is 3% by volume or less. Hydrogen gas mass (g) in the reference container 36 (capacity: 3.4 liters) and hydrogen gas mass (g in the filling target container (capacity: 47 liters) Z according to the hydrogen content of the mixed gas containing hydrogen. ) Is shown in Table 1. Table 2 shows the helium gas mass (g) in the reference container 36 and the helium gas mass (g) in the filling target container Z according to the helium content of the mixed gas containing helium.

[0029]

[Table 1]

[0030]

[Table 2]

In the pressure filling system, since the mixed gas filling pressure in the container Z to be filled is 14.7 MPa, when filling the mixed gas having a hydrogen gas or helium gas content of 6% by volume or less, hydrogen gas and helium are filled. Gas filling pressure is 0.9
It will be below MPa. In this case, the design pressure of the equipment and piping of the first gas supply system 4 can be set to 1 MPa, so the first gas supply system 4 is not subject to the High Pressure Gas Safety Act. Therefore, a general-purpose device or the like can be used, and the manufacturing cost can be reduced. Further, the first gas supply system can be added to the existing filling device of the mass filling method at low cost.

Further, by making the full scale of the pressure gauge small (for example, 1 MPa), the minimum scale of the pressure gauge can be made small and the accuracy of the gas filling amount can be improved. Further, the filling method of the present invention can obtain a particularly excellent effect when a gas having a molecular weight of 10 or less is used as the gas having a small molecular weight. As the target gas of the present invention, hydrogen, helium, oxygen, nitrogen, argon, carbon dioxide are shown, but the gas is not limited to these, and other silanes and phosphines used for the production of semiconductors are used. It is also possible to target a mixed gas containing such as.

[0033]

EXAMPLES Example 1 Using the mixed gas filling apparatus shown in FIG. 1, a hydrogen-argon mixed gas containing 1% by volume of hydrogen was added to a 47-liter target filling container (cylinder) Z as shown below. Was charged at a pressure of 14.7 MPa. In this embodiment, hydrogen (H2) is used as a gas having a small molecular weight,
The hydrogen (H2) was charged into the container Z by using the pressure filling method, and then the container Z was charged with argon (Ar) gas having a large molecular weight by the mass filling method. The filling mode of each component gas is as follows.・ Hydrogen filling pressure: 0.15 MPa ・ Argon filling volume into the reference container 36: 90
As the 0.5 g reference container 36, a cylinder having a capacity of 3.4 liters was used. After leaving the container Z filled with the mixed gas for 20 hours, the mixed gas in the container was analyzed by gas chromatography. This mixed gas filling was repeated 3 times to verify the reproducibility. The results are shown in Table 3. As is clear from Table 3, it was confirmed that the hydrogen-argon mixed gas containing 1% by volume of hydrogen (H2) can be filled with sufficient accuracy and reproducibility.

[0034]

[Table 3]

<Mass Filling Method> Using the mixed gas filling apparatus shown in FIG. 1, an oxygen-nitrogen mixed gas containing 21% by volume of oxygen (O2) was added to a 47-liter container (cylinder) by a conventional mass filling method. ) Z was charged at a pressure of 14.7 MPa. That is, the container Z was filled with oxygen gas by the mass filling method, and then the container Z was filled with the nitrogen gas by the mass filling method. Filling mass of oxygen into the reference container 36: 153 g. Filling mass of nitrogen into the reference container 36: 503.
As the 6 g reference container 36, a cylinder having a capacity of 3.4 liters was used.

After leaving the container Z filled with the mixed gas for 20 hours, the mixed gas in the container Z was analyzed by gas chromatography. This mixed gas filling was repeated 3 times to verify the reproducibility. The results are shown in Table 4. As is clear from Table 4, it was confirmed that the nitrogen (N2) mixed gas containing 21% by volume of oxygen (O2) can be filled and manufactured with sufficient accuracy and reproducibility.

[0037]

[Table 4]

[0038]

In the mixed gas filling method of the present invention, first, a gas having a small molecular weight is filled by a pressure filling method, and then a gas having a relatively large molecular weight is filled by a mass filling method, thereby increasing the pressure at the time of filling. It is possible to perform the filling with high accuracy and reproducibility without being affected by the pressure fluctuation due to the temperature rise due to.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of a mixed gas filling device according to the present invention.

FIG. 2 is a schematic diagram of a conventional pressure filling type mixed gas filling device.

FIG. 3 is a schematic diagram of a conventional mass filling type mixed gas filling device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mixed gas filling device, 2 ... Gas supply system, 3 ... Reference system, 4 ... 1st gas supply system, 5 ... 2nd gas supply type, 6
... Common gas supply system, 11, 21, 31, 41 ... Supply valve,
12 ... Pressure reducing valve, 13 ... Needle valve, 14, 24, 3
4, 44 ... Check valve, 15, 17 ... Pressure gauge (pressure detection means), 20 ... Thermometer, 16, 18 ... Safety valve, 19, 37
... Blow valve, 25, 35 ... Valve, 36 ... Reference container, 38 ... Load cell (mass detecting means), Ga, Gb, G
c, Gd ... Component gas source, Ta, Tb, Tc, Td, Tad, Tr
… Pipe, Z… Container to be filled

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Claims (3)

[Claims] 1. When filling a container with a mixed gas composed of a plurality of gas components, a gas having a small molecular weight among the gas components is filled in a predetermined amount by a pressure filling method, and then a gas having a relatively large molecular weight is mass filled. A method for filling a mixed gas, which comprises filling with 2. A first gas supply system for supplying a gas having a small molecular weight, a second gas supply system for supplying a gas having a relatively large molecular weight, and a gas from these first and second gas supply systems in a container. A common supply system for supplying gas, wherein the first supply system is provided with pressure detection means for detecting gas pressure, and the second supply system or the common gas supply system is provided with mass detection means for detecting gas mass. Characterized mixed gas filling device. 3. The mixed gas filling device according to claim 2, wherein at least one of the first gas supply system and the second gas supply system includes a plurality of systems for supplying gas components.