JP2538272B2 - Method for measuring hydrogen concentration in soil gas - Google Patents
Method for measuring hydrogen concentration in soil gasInfo
- Publication number
- JP2538272B2 JP2538272B2 JP62223397A JP22339787A JP2538272B2 JP 2538272 B2 JP2538272 B2 JP 2538272B2 JP 62223397 A JP62223397 A JP 62223397A JP 22339787 A JP22339787 A JP 22339787A JP 2538272 B2 JP2538272 B2 JP 2538272B2
- Authority
- JP
- Japan
- Prior art keywords
- gas
- hydrogen concentration
- soil
- soil gas
- concentration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000002680 soil gas Substances 0.000 title claims description 62
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims description 51
- 239000001257 hydrogen Substances 0.000 title claims description 45
- 229910052739 hydrogen Inorganic materials 0.000 title claims description 45
- 238000000034 method Methods 0.000 title claims description 14
- 239000007789 gas Substances 0.000 claims description 43
- 239000001301 oxygen Substances 0.000 claims description 25
- 229910052760 oxygen Inorganic materials 0.000 claims description 25
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 24
- 239000004065 semiconductor Substances 0.000 claims description 24
- 239000002689 soil Substances 0.000 claims description 2
- 238000005070 sampling Methods 0.000 description 13
- 238000010586 diagram Methods 0.000 description 9
- 238000001035 drying Methods 0.000 description 9
- 238000005259 measurement Methods 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 7
- 229910001882 dioxygen Inorganic materials 0.000 description 7
- 239000010409 thin film Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 2
- 239000002274 desiccant Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Geophysics And Detection Of Objects (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、土壌ガス中の水素濃度の測定方法に関す
る。TECHNICAL FIELD The present invention relates to a method for measuring hydrogen concentration in soil gas.
［従来の技術］ 地殻変動によって破壊された地中岩石の破断面から水
素ガスが放出されることはよく知られており、土壌ガス
中の水素濃度の測定は、地震予知や、火山噴火予知に有
用である。[Prior art] It is well known that hydrogen gas is released from the fracture surface of underground rocks destroyed by crustal movement, and the measurement of hydrogen concentration in soil gas is useful for earthquake prediction and volcanic eruption prediction. It is useful.
第３図は、従来の土壌ガス中の水素濃度の測定方法を
示す測定系の構成図である。FIG. 3 is a block diagram of a measurement system showing a conventional method for measuring the hydrogen concentration in soil gas.
符号20は、地表18から適当な深さに掘削された観測孔
中に埋設されたステンレス製な観測管であって、下端周
辺には土壌ガス２の採取口22が形成され、上端はシール
24によって密閉されている。観測管20内において、採取
口22の近傍には半導体式ガスセンサ８が配される。この
センサは、例えば酸化すずSnO2からなるｎ型半導体薄膜
を有する。この薄膜は、水素ガスに感応して抵抗率が変
化するものである。符号10はこのガスセンサのリード線
であって、シール24を貫通して地上において観測管20の
外部に導かれている。Reference numeral 20 is a stainless steel observation tube buried in an observation hole drilled from the ground surface 18 to an appropriate depth. A sampling port 22 for soil gas 2 is formed around the lower end and a seal is provided at the upper end.
It is sealed by 24. In the observation tube 20, the semiconductor gas sensor 8 is arranged near the sampling port 22. This sensor has an n-type semiconductor thin film made of, for example, tin oxide S n O 2 . This thin film changes its resistivity in response to hydrogen gas. Reference numeral 10 is a lead wire of this gas sensor, which penetrates the seal 24 and is guided to the outside of the observation tube 20 on the ground.
土壌ガス２は、採取口22を通して観測管20内に採取さ
れる。半導体式ガスセンサ８のｎ型半導体薄膜は、この
土壌ガス２中の水素ガスに感応して抵抗率が変化し、リ
ード線10を通してセンシング信号を出力する。この出力
信号の電圧は、土壌ガス２中に含まれる水素ガスの濃度
が高くなるほど大きくなる。半導体式ガスセンサ８は通
常常時作動しており、出力信号は例えばリモートセンシ
ングされる。The soil gas 2 is sampled in the observation tube 20 through the sampling port 22. The resistivity of the n-type semiconductor thin film of the semiconductor gas sensor 8 changes in response to the hydrogen gas in the soil gas 2, and the sensing signal is output through the lead wire 10. The voltage of this output signal increases as the concentration of hydrogen gas contained in the soil gas 2 increases. The semiconductor gas sensor 8 is normally in operation at all times, and the output signal is, for example, remotely sensed.
第４図は、従来の他の測定方法を示す測定系の構成図
である。FIG. 4 is a block diagram of a measuring system showing another conventional measuring method.
符号40は、地表18から適当な深さまで直立して埋設さ
れた土壌ガス２の採取管である。この採取管40の地上部
分は、乾燥剤が封入された乾燥管42の一端に接続され、
乾燥管42の他端は、観測部44に接続されている。観測部
44には前記と同様の半導体式ガスセンサ８が配され、リ
ード線10がシール24を通して観測部44の外部に導かれて
いる。さらに、観測部44は、ポンプ46を介して排出管48
の一端に接続されている。排出管48の他端は、前記採取
管40と同様に地中に埋設されている。Reference numeral 40 is a sampling pipe for the soil gas 2 which is buried upright from the ground surface 18 to an appropriate depth. The above-ground portion of the sampling pipe 40 is connected to one end of a drying pipe 42 in which a desiccant is enclosed,
The other end of the drying tube 42 is connected to the observation section 44. Observation department
The same semiconductor gas sensor 8 as described above is arranged at 44, and the lead wire 10 is guided to the outside of the observation section 44 through the seal 24. Further, the observing unit 44 is connected to the discharge pipe 48 via the pump 46.
Is connected to one end. The other end of the discharge pipe 48 is buried in the ground like the collecting pipe 40.
ポンプ46は、通常、水素濃度測定前の一定時間だけ運
転される。ポンプ46が運転されると、土壌ガス２は、採
取管40を通して乾燥管42に導かれ、これを通過する際に
水蒸気が除去される。乾燥した土壌ガス２は観測部44に
至り、ポンプ46及び排出管48を通して地中に戻される。
したがって、ポンプ46を運転すると、土壌ガス２が採取
管40、乾燥管42、観測部44、ポンプ46及び排出管48を通
して循環し、観測部44内の水素濃度が定常値となる。こ
の水素濃度は半導体式ガスセンサ８によってセンシング
され、このセンサの出力信号は、例えば一定時間ごとに
データロガに記憶される。なお、半導体式ガスセンサ８
は水素ガスばかりでなく水蒸気にも感応するが、乾燥管
42において水蒸気が除去されているため、前記の方法に
比較して土壌ガス中の水素濃度を正確に測定することが
できる。The pump 46 is normally operated only for a certain period of time before measuring the hydrogen concentration. When the pump 46 is operated, the soil gas 2 is guided to the drying pipe 42 through the sampling pipe 40, and water vapor is removed when passing through the drying pipe 42. The dried soil gas 2 reaches the observation section 44 and is returned to the ground through the pump 46 and the discharge pipe 48.
Therefore, when the pump 46 is operated, the soil gas 2 circulates through the sampling pipe 40, the drying pipe 42, the observation unit 44, the pump 46 and the discharge pipe 48, and the hydrogen concentration in the observation unit 44 becomes a steady value. This hydrogen concentration is sensed by the semiconductor gas sensor 8, and the output signal of this sensor is stored in the data logger at regular intervals, for example. The semiconductor gas sensor 8
Is sensitive to not only hydrogen gas but also water vapor, but the drying tube
Since the water vapor is removed at 42, the hydrogen concentration in the soil gas can be measured more accurately than in the above method.
［発明が解決しようとする問題点］ さて、半導体ガスセンサは、本来大気中で使用するこ
とを目的として開発されたものであって、これに用いら
れるｎ型半導体薄膜は、水素ガスや水蒸気ばかりでなく
酸素ガスにも感応するが、大気中の酸素濃度は一定であ
るので、大気中でこのセンサを使用する場合には支障が
なかった。[Problems to be Solved by the Invention] The semiconductor gas sensor was originally developed for the purpose of being used in the atmosphere, and the n-type semiconductor thin film used for this is not limited to hydrogen gas and water vapor. It is also sensitive to oxygen gas, but since the oxygen concentration in the atmosphere is constant, there was no problem when using this sensor in the atmosphere.
しかしながら、土壌ガス中の酸素濃度は時々刻々変化
するので、従来の方法では水素濃度の測定を正確に行う
ことができなかった。すなわち、従来は、以上に説明し
たように水蒸気濃度の影響を除去することは行なわれて
いたものの、採取した土壌ガスそのものを半導体ガスセ
ンサに接触させていたため、酸素濃度変化の影響が直接
ガスセンサ出力に現れ、土壌ガス中の水素濃度を正確に
測定することができなかった。However, since the oxygen concentration in the soil gas changes from moment to moment, it has not been possible to accurately measure the hydrogen concentration by the conventional method. That is, in the past, although the effect of water vapor concentration was removed as described above, the effect of oxygen concentration change was directly on the gas sensor output because the collected soil gas itself was contacted with the semiconductor gas sensor. Appeared and could not measure hydrogen concentration in soil gas accurately.
本発明は、以上の点に鑑みてなされたものであって、
酸素濃度変化の影響を緩和して、従来より正確な水素濃
度を得ることができる土壌ガス中の水素濃度の測定方法
を提供することを目的とする。The present invention has been made in view of the above points,
An object of the present invention is to provide a method for measuring the hydrogen concentration in soil gas, which can alleviate the effect of changes in oxygen concentration and obtain more accurate hydrogen concentration than ever before.
［問題点を解決するための手段］ 本発明は、前記の目的を達成するために、土壌ガスと
大気との混合ガス中の水素濃度を半導体式ガスセンサで
測定し、得られた水素濃度を土壌ガスと大気との混合比
に基づいて修正するものである。[Means for Solving Problems] In order to achieve the above-mentioned object, the present invention measures the hydrogen concentration in a mixed gas of soil gas and the atmosphere with a semiconductor gas sensor, and obtains the obtained hydrogen concentration in the soil. It is corrected based on the mixing ratio of gas and atmosphere.
［作 用］ 例えば土壌ガス中の酸素濃度が0.1％から10％まで変
化しても大気中の酸素濃度は一定の21％であるから、土
壌ガスと大気との混合比を1:1とした場合には、この混
合ガス中の酸素濃度は、10.5％から15.5％まで変化する
だけである。したがって、土壌ガスそのものの酸素濃度
変化率が100:1であるのに対して、この混合ガス中の酸
素濃度変化率は、1.5:1と大幅に減少する。酸素濃度変
化の小さい混合ガスについては、この変化の影響をあま
り受けずに、半導体式ガスセンサによって水素濃度を測
定することができる。このセンサによって正確に得られ
た水素濃度は、さらに土壌ガスと大気との混合比に基づ
いて修正され、土壌ガス中の正確な水素濃度が得られ
る。例えば前記のように混合比が1:1である場合には、
混合ガス中の水素濃度を２倍すれば、土壌ガス中の正確
な水素濃度が得られる。[Operation] For example, even if the oxygen concentration in soil gas changes from 0.1% to 10%, the oxygen concentration in the atmosphere is constant at 21%, so the mixing ratio of soil gas and atmosphere was set to 1: 1. In some cases, the oxygen concentration in this gas mixture only changes from 10.5% to 15.5%. Therefore, the change rate of oxygen concentration in the soil gas itself is 100: 1, whereas the change rate of oxygen concentration in this mixed gas is significantly reduced to 1.5: 1. For a mixed gas with a small change in oxygen concentration, the hydrogen concentration can be measured by a semiconductor gas sensor without being affected by this change. The hydrogen concentration accurately obtained by this sensor is further corrected on the basis of the mixture ratio of soil gas and air to obtain an accurate hydrogen concentration in soil gas. For example, when the mixing ratio is 1: 1 as described above,
By doubling the hydrogen concentration in the mixed gas, the correct hydrogen concentration in the soil gas can be obtained.
［実施例］ 第１図は、本発明の実施例に係る水素濃度測定方法を
示す測定系の構成図である。[Example] FIG. 1 is a configuration diagram of a measurement system showing a hydrogen concentration measuring method according to an example of the present invention.
地中に埋設された観測管20は、従来と同様に下端周辺
に土壌ガス２の採取口22を有するとともに、上端がシー
ル24によって密閉されている。SnO2からなるｎ型半導体
薄膜を有する半導体式ガスセンサ８は、観測管20内にお
いて採取口22の近傍に配される。ｎ型半導体薄膜の構成
材料は他のものであってもよいが、高真空度下のスパッ
タリングにより形成したSnO2薄膜が、メタンに対する感
度が低く、水素に対する選択性が特に高いので好都合で
ある。この半導体式ガスセンサ８は、シール24を貫通す
るリード線10を通してセンシング信号を出力する。The observation tube 20 buried in the ground has a sampling port 22 for the soil gas 2 around the lower end as in the conventional case, and the upper end is sealed by a seal 24. The semiconductor gas sensor 8 having an n-type semiconductor thin film made of S n O 2 is arranged in the observation tube 20 near the sampling port 22. the material of the n-type semiconductor thin film may be of other, S n O 2 thin film formed by sputtering under high vacuum degree of sensitivity to methane is low, convenient and since particularly high selectivity to hydrogen is there. The semiconductor gas sensor 8 outputs a sensing signal through the lead wire 10 penetrating the seal 24.
混合管30は、一端が測定管20内において開口するよう
にシール24を貫通して設けられ、地上部分にリークバル
ブ32が配される。吸入管34も同様にシール24を貫通して
設けられ、測定管20の外部において、ポンプ46を介して
排出管48の一端に接続されている。排出管48は、地表18
から適当な深さまで直立して埋設され、他端が地中に開
口している。The mixing pipe 30 is provided so as to penetrate the seal 24 so that one end thereof is opened in the measurement pipe 20, and a leak valve 32 is arranged in the ground portion. The suction pipe 34 is also provided so as to penetrate the seal 24, and is connected to one end of the discharge pipe 48 via the pump 46 outside the measurement pipe 20. The discharge pipe 48 is at the surface 18
It is buried upright up to an appropriate depth, and the other end opens into the ground.
土壌ガス２は、採取口22を通して観測管20内に採取さ
れる。一方、リークバルブ32を開放してポンプ46を運転
すると、混合管30を通して観測管20内に大気４が吸入さ
れ、観測管20内において土壌ガス２と大気４とが混合さ
れる。この混合ガス６は、吸入管34を通してポンプ46に
吸入され、排出管48を通して地中に排出される。排出さ
れた混合ガス６は、土壌ガス２とともに採取口22を通し
て観測管20内に入る。したがって、土壌ガス２は、測定
管20、吸入管34、ポンプ46及び排出管48を通して循環
し、一定時間後に観測管20内の水素濃度が定常値とな
る。The soil gas 2 is sampled in the observation tube 20 through the sampling port 22. On the other hand, when the leak valve 32 is opened and the pump 46 is operated, the atmosphere 4 is sucked into the observation tube 20 through the mixing tube 30, and the soil gas 2 and the atmosphere 4 are mixed in the observation tube 20. The mixed gas 6 is sucked into the pump 46 through the suction pipe 34 and discharged into the ground through the discharge pipe 48. The discharged mixed gas 6 enters the observation tube 20 through the sampling port 22 together with the soil gas 2. Therefore, the soil gas 2 circulates through the measurement pipe 20, the suction pipe 34, the pump 46, and the discharge pipe 48, and the hydrogen concentration in the observation pipe 20 becomes a steady value after a certain time.
一方、土壌ガス２中の酸素ガスも採取口22を通して観
測管20内に採取されているが、大気中の酸素ガスが混合
管30を通して供給されるため、観測管20内の酸素濃度
は、大気４を吸入しない場合に比較して高くなる。この
際、例えば土壌ガス２中の酸素濃度が0.1％から10％ま
で変化しても、リークバルブ32の開度を調節することに
よって、土壌ガス２と大気４との混合比を1:1とした場
合には、混合ガス６中の酸素濃度は、10.5％から15.5％
まで変化するだけである。つまり、土壌ガス２そのもの
の酸素濃度変化率が100:1であるのに対して、混合ガス
６中の酸素濃度変化率は、1.5:1と大幅に減少する。し
たがって、この酸素濃度変化の小さい混合ガス６につい
ては、酸素濃度変化の影響をあまり受けずに、半導体式
ガスセンサ８によって水素濃度を測定することができ
る。このセンサによって得られた水素濃度は、さらに土
壌ガス２と大気４との混合比に基づいて修正され、土壌
ガス２中の正確な水素濃度が得られる。例えば混合比が
1:1である場合には、得られた混合ガス６中の水素濃度
を２倍すれば、土壌ガス２中の正確な水素濃度が得られ
る。On the other hand, the oxygen gas in the soil gas 2 is also sampled in the observation tube 20 through the sampling port 22, but since the oxygen gas in the atmosphere is supplied through the mixing tube 30, the oxygen concentration in the observation tube 20 is It is higher than that when 4 is not inhaled. At this time, for example, even if the oxygen concentration in the soil gas 2 changes from 0.1% to 10%, by adjusting the opening degree of the leak valve 32, the mixing ratio of the soil gas 2 and the atmosphere 4 becomes 1: 1. The oxygen concentration in the mixed gas 6 is 10.5% to 15.5%.
It just changes. That is, the rate of change in oxygen concentration of the soil gas 2 itself is 100: 1, whereas the rate of change in oxygen concentration in the mixed gas 6 is significantly reduced to 1.5: 1. Therefore, for the mixed gas 6 having a small change in oxygen concentration, the hydrogen concentration can be measured by the semiconductor gas sensor 8 without being affected by the change in oxygen concentration. The hydrogen concentration obtained by this sensor is further corrected based on the mixing ratio of the soil gas 2 and the atmosphere 4 to obtain an accurate hydrogen concentration in the soil gas 2. For example, if the mixing ratio is
In the case of 1: 1, by doubling the hydrogen concentration in the obtained mixed gas 6, the correct hydrogen concentration in the soil gas 2 can be obtained.
第２図は、本発明の他の実施例に係る水素濃度測定方
法を示す測定系の構成図である。FIG. 2 is a configuration diagram of a measuring system showing a hydrogen concentration measuring method according to another embodiment of the present invention.
第４図に示した従来の測定系の構成と異なるのは、観
測部44に代えて混合室45が設けられ、この混合室45内に
大気４を供給するための混合管30が接続され、混合管30
にリークバルブ32が配される点だけである。半導体式ガ
スセンサ８は、混合室45内に配される。The difference from the configuration of the conventional measurement system shown in FIG. 4 is that a mixing chamber 45 is provided in place of the observation unit 44, and a mixing pipe 30 for supplying the atmosphere 4 is connected to the mixing chamber 45. Mixing tube 30
This is the only point where the leak valve 32 is arranged. The semiconductor gas sensor 8 is arranged in the mixing chamber 45.
ポンプ46が運転されると、採取管40を通して採取され
た土壌ガス２は、乾燥管42を通過する際に水蒸気が除去
された後、混合室45内に導かれる。なお、本実施例では
土壌ガス２の乾燥に乾燥剤を用いているが、土壌ガス２
を圧縮又は冷却して物理的に水蒸気を除去してもよく、
さらに他の方法であってもよい。When the pump 46 is operated, the soil gas 2 collected through the sampling pipe 40 is introduced into the mixing chamber 45 after the water vapor is removed while passing through the drying pipe 42. Although a desiccant is used to dry the soil gas 2 in this example, the soil gas 2
May be compressed or cooled to physically remove water vapor,
Still another method may be used.
土壌ガス２中に含まれる酸素ガスは、乾燥管42におい
て除去されることがないため、水素ガスとともに混合室
45内に導入されるが、混合室45内には混合管30及びリー
クバルブ32を通して大気が供給されるため、混合室45内
の混合ガス６中の酸素ガスの濃度変化率は、土壌ガス２
そのものと比較して減少する。したがって、先の実施例
の場合と同様に、混合ガス６中の水素濃度を半導体式ガ
スセンサ８で測定し、得られた水素濃度を土壌ガス２と
大気４との混合比に基づいて修正することにより、土壌
ガス２中の酸素濃度変化の影響をあまり受けずに水素濃
度を正確に測定することができる。しかも、本実施例で
は、乾燥させた土壌ガス２に大気４を混合しているた
め、水蒸気濃度の影響をも除去することができ、土壌ガ
ス２中の水素濃度をさらに正確に測定することができ
る。Since the oxygen gas contained in the soil gas 2 is not removed in the drying pipe 42, it is mixed with hydrogen gas in the mixing chamber.
Although it is introduced into the mixing chamber 45, since the atmosphere is supplied into the mixing chamber 45 through the mixing pipe 30 and the leak valve 32, the concentration change rate of the oxygen gas in the mixed gas 6 in the mixing chamber 45 is equal to the soil gas 2
It decreases compared to itself. Therefore, as in the case of the previous embodiment, the hydrogen concentration in the mixed gas 6 should be measured by the semiconductor gas sensor 8 and the obtained hydrogen concentration should be corrected based on the mixing ratio of the soil gas 2 and the atmosphere 4. As a result, the hydrogen concentration can be accurately measured without being significantly affected by the change in oxygen concentration in the soil gas 2. Moreover, in this embodiment, since the atmosphere 4 is mixed with the dried soil gas 2, the influence of the water vapor concentration can be removed, and the hydrogen concentration in the soil gas 2 can be measured more accurately. it can.
なお、以上に説明した両実施例において、半導体式ガ
スセンサ８の近傍に酸素ガスセンサを配して混合ガス６
中の酸素濃度を測定し、この酸素濃度を一定に保つよう
にリークバルブ32の開度を調節して、土壌ガス２と大気
４との混合比を制御することができる。これにより、混
合ガス６中の酸素濃度変化をなくして、さらに正確に土
壌ガス２中の水素濃度を測定することができる。なお、
酸素ガスセンサとしては、ガルバニセルや磁気式センサ
等を使用することができる。In both of the embodiments described above, an oxygen gas sensor is arranged in the vicinity of the semiconductor gas sensor 8 and the mixed gas 6
It is possible to control the mixture ratio of the soil gas 2 and the atmosphere 4 by measuring the oxygen concentration in the inside and adjusting the opening degree of the leak valve 32 so as to keep this oxygen concentration constant. As a result, the change in oxygen concentration in the mixed gas 6 can be eliminated, and the hydrogen concentration in the soil gas 2 can be measured more accurately. In addition,
As the oxygen gas sensor, a galvanic cell, a magnetic sensor or the like can be used.
［発明の効果］ 以上に説明したように、本発明は、土壌ガスと大気と
の混合ガス中の水素濃度を半導体式ガスセンサ測定し、
得られた水素濃度を土壌ガスと大気との混合比に基づい
て修正するものであるから、土壌ガス中の酸素濃度が変
化しても混合ガス中の酸素濃度変化率を低くすることが
できる。したがって、本発明によれば、土壌ガス中の酸
素濃度変化の影響を緩和して、従来より正確に土壌ガス
中の水素濃度の測定を行うことができる。[Effects of the Invention] As described above, the present invention measures the hydrogen concentration in a mixed gas of soil gas and the atmosphere by a semiconductor gas sensor,
Since the obtained hydrogen concentration is corrected based on the mixing ratio of soil gas and air, even if the oxygen concentration in the soil gas changes, the oxygen concentration change rate in the mixed gas can be lowered. Therefore, according to the present invention, it is possible to alleviate the effect of changes in oxygen concentration in soil gas and to measure hydrogen concentration in soil gas more accurately than ever before.
第１図は、本発明の実施例に係る土壌ガス中の水素濃度
の測定方法を示す測定系の構成図、 第２図は、本発明の他の実施例に係る土壌ガス中の水素
濃度の測定方法を示す測定系の構成図、 第３図は、従来の土壌ガス中の水素濃度の測定方法を示
す測定系の構成図、 第４図は、従来の土壌ガス中の水素濃度の他の測定方法
を示す測定系の構成図である。 符号の説明 ２……土壌ガス、４……大気、６……混合ガス、８……
半導体式ガスセンサ、32……リークバルブ、42……乾燥
管、46……ポンプ。FIG. 1 is a configuration diagram of a measurement system showing a method for measuring hydrogen concentration in soil gas according to an embodiment of the present invention, and FIG. 2 is a diagram showing hydrogen concentration in soil gas according to another embodiment of the present invention. Fig. 3 is a block diagram of a measuring system showing a measuring method, Fig. 3 is a block diagram of a measuring system showing a conventional measuring method of hydrogen concentration in soil gas, and Fig. 4 is another conventional hydrogen concentration in soil gas. It is a block diagram of a measurement system showing a measurement method. Explanation of code 2 …… Soil gas, 4 …… Atmosphere, 6 …… Mixed gas, 8 ……
Semiconductor gas sensor, 32 ... Leak valve, 42 ... Drying tube, 46 ... Pump.
Claims (3)
を半導体式ガスセンサで測定し、得られた水素濃度を土
壌ガスと大気との混合比に基づいて修正することを特徴
とする土壌ガス中の水素濃度の測定方法。1. A soil characterized in that the hydrogen concentration in a mixed gas of soil gas and the atmosphere is measured by a semiconductor gas sensor, and the obtained hydrogen concentration is corrected based on the mixing ratio of the soil gas and the atmosphere. Measuring method of hydrogen concentration in gas.
を特徴とする特許請求の範囲第１項記載の土壌ガス中の
水素濃度の測定方法。2. The method for measuring the hydrogen concentration in soil gas according to claim 1, wherein the dried soil gas is mixed with the atmosphere.
混合比を制御することを特徴とする特許請求の範囲第１
項又は第２項記載の土壌ガス中の水素濃度の測定方法。3. A mixing ratio is controlled so that the oxygen concentration in the mixed gas is kept constant.
Item 2. The method for measuring the hydrogen concentration in soil gas according to Item 2 or Item 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62223397A JP2538272B2 (en) | 1987-09-07 | 1987-09-07 | Method for measuring hydrogen concentration in soil gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62223397A JP2538272B2 (en) | 1987-09-07 | 1987-09-07 | Method for measuring hydrogen concentration in soil gas |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6466554A JPS6466554A (en) | 1989-03-13 |
| JP2538272B2 true JP2538272B2 (en) | 1996-09-25 |
Family
ID=16797507
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62223397A Expired - Lifetime JP2538272B2 (en) | 1987-09-07 | 1987-09-07 | Method for measuring hydrogen concentration in soil gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2538272B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9797814B2 (en) | 2011-06-12 | 2017-10-24 | Adi Mottes | Probe for in situ monitoring the electrical conductivity of soil solutions |
| CN103592675A (en) * | 2013-11-27 | 2014-02-19 | 陈国梁 | Method for monitoring and forecasting earthquakes by using change of hydrogen content in soil |
| CN117890997B (en) * | 2024-03-15 | 2024-06-18 | 核工业航测遥感中心 | Method for rapidly identifying sulfide polymetallic ore based on soil hydrogen |
-
1987
- 1987-09-07 JP JP62223397A patent/JP2538272B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6466554A (en) | 1989-03-13 |
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