JP2004053357A - Collecting method and measuring method of yellow sand particle - Google Patents

Collecting method and measuring method of yellow sand particle Download PDF

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Publication number
JP2004053357A
JP2004053357A JP2002209713A JP2002209713A JP2004053357A JP 2004053357 A JP2004053357 A JP 2004053357A JP 2002209713 A JP2002209713 A JP 2002209713A JP 2002209713 A JP2002209713 A JP 2002209713A JP 2004053357 A JP2004053357 A JP 2004053357A
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yellow sand
particles
sand particles
collected
particle size
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Japanese (ja)
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Shinichiro Totoki
十時 慎一郎
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Shimadzu Corp
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Shimadzu Corp
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Priority to JP2002209713A priority Critical patent/JP2004053357A/en
Priority to US10/322,677 priority patent/US6807874B2/en
Priority to KR1020030046419A priority patent/KR100554531B1/en
Priority to CNB031475213A priority patent/CN1288433C/en
Publication of JP2004053357A publication Critical patent/JP2004053357A/en
Priority to US10/882,621 priority patent/US6923848B2/en
Priority to US11/048,895 priority patent/US7041153B2/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34Constructional details or accessories or operation thereof
    • B03C3/40Electrode constructions
    • B03C3/41Ionising-electrodes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/02Plant or installations having external electricity supply
    • B03C3/04Plant or installations having external electricity supply dry type
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/017Combinations of electrostatic separation with other processes, not otherwise provided for
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34Constructional details or accessories or operation thereof
    • B03C3/40Electrode constructions
    • B03C3/45Collecting-electrodes
    • B03C3/47Collecting-electrodes flat, e.g. plates, discs, gratings
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C2201/00Details of magnetic or electrostatic separation
    • B03C2201/10Ionising electrode has multiple serrated ends or parts
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/02Devices for withdrawing samples
    • G01N1/22Devices for withdrawing samples in the gaseous state
    • G01N1/24Suction devices

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently collect yellow sand particles existing in the air, observe the collected yellow sand particles by a microscope, easily apply the collected yellow sand particle to various analysis instruments, measure a granularity distribution of the collected yellow sand particles at high resolution and also measure a yellow sand particle concentration. <P>SOLUTION: The air is sucked in a collection container 1 by a pump 2. Particles P including the yellow sand particles contained in the air are charged by unipolar ions from a discharge electrode 3 disposed in the collection container 1. The yellow sand particles are collected on a dust collection electrode 4 having a potential difference between the discharge electrode 3. The collected particles P can be respectively extracted. When the collected particles P as a measured object are measured, a laser diffracting/dispersing granularity distribution measurement apparatus 20 is used and finds the granularity distribution and the particle concentration only in a preset particle diameter range of the yellow sand particles, the granularity distribution of the yellow sand particles in the air can be measured at high resolution and the yellow sand particle concentration can be also measured. <P>COPYRIGHT: (C)2004,JPO

Description

【0001】
【発明の属する技術分野】
本発明は、大気中に浮遊する黄砂粒子の捕集方法と、その方法により捕集した黄砂粒子の測定方法に関する。
【0002】
【従来の技術】
黄砂は、中国大陸奥地の砂漠の砂が強風に舞い上げられ、上空の偏西風に流されて海を渡り、日本にまで飛んでくる。黄砂の粒子径は場所によって異なり、発生源に近い中国大陸では20〜30μm、発生源から遠い日本では4〜5μm程度と言われている。
【0003】
このような大気中の黄砂粒子の形状等を調査したり、あるいはそこに含まれている化学物質を同定するには、大気中から黄砂粒子をフィルタを用いて捕集し、顕微鏡で観察したり、あるいは化学分析を行っている。
【0004】
また、このような黄砂粒子の粒度分布を測定する装置としては、従来、カスケードインパクタ方式に基づく装置が実用化されている。このカスケードインパクタ方式に基づく測定装置は、流体を捕集板に衝突させてその流れの方向を急変させることによって粒子を流体から分離するインパクタ法を利用したものであり、50%捕集効率の粒径を順次変化させたインパクタを多段に直列接続して、各段における50%捕集効率の粒径をそれぞれの段の代表径として、それぞれの段における捕集量の測定結果から、流体中の粒度分布を求めるものである。
【0005】
【発明が解決しようとする課題】
ところで、大気中に浮遊する黄砂粒子を顕微鏡で観察したり、あるいは各種化学分析機器に供すべくフィルタにより捕集する方法では、特に日本に飛来する粒子が前記したように4〜5μm程度と細かいために、個々の粒子を単独で抽出することが極めて困難であり、顕微鏡により観察するに当たってはフィルタに付着した状態の黄砂粒子を観察することになるが、その場合、背景のフィルタ像で粒子の像が不鮮明となり、観察しにくいという問題がある。また、捕集した黄砂粒子を各種分析機器に供する場合においても、フィルタから黄砂粒子を単独で抽出することが困難であることから、機器によってはフィルタに付着した状態で分析を行う必要があり、その場合、例えば蛍光X線分析装置などにおいては粒子のみにX線を照射することが困難となって、実質的に分析不能となったり、あるいは、前処理が難しいなどといった問題がある。
【0006】
また、従来のカスケードインパクタ方式に基づく従来の測定装置を用いて、黄砂粒子の粒度分布を測定する場合、その原理上、粒径の分解能が捕集板の数によって決まってしまうために、高い分解能で粒度分布を測定することは望めない。
【0007】
本発明はこのような実情に鑑みてなされたもので、大気中に存在する黄砂粒子を効率的に捕集し、しかも捕集した黄砂粒子を顕微鏡で観察したり、あるいは各種分析機器に供することが極めて容易な黄砂粒子の捕集方法と、捕集した黄砂粒子の粒度分布および粒子濃度を高い分解能のもとに測定することのできる黄砂粒子の測定方法の提供を目的としている。
【0008】
【課題を解決するための手段】
上記の目的を達成するため、本発明の黄砂粒子の捕集方法は、大気中に含まれる黄砂粒子を捕集する方法であって、大気をポンプにより容器内に吸引するとともに、その容器内に配置した放電電極で発生させた単極イオンにより、大気中の黄砂粒子を含む浮遊粒子を帯電させ、その帯電粒子を、上記容器内で放電電極に対して電位差が与えられた集塵電極上に捕集することによって特徴づけられる。
【0009】
本発明の黄砂粒子の捕集方法においては、内部に放電電極と集塵電極を配置した容器内に大気を吸引し、放電電極からの単極イオンで大気中の黄砂粒子を帯電させて集塵電極の表面に捕集するため、捕集した黄砂粒子を容易に単独で抽出することが可能であって、各種分析機器に容易に供することができ、顕微鏡による観察も容易となる。
【0010】
一方、本発明の黄砂粒子の測定方法は、請求項1に記載の方法により捕集した粒子を分散状態に維持した状態で、レーザ光を照射して得られる回折・散乱光の空間強度分布を測定し、その測定結果から、黄砂粒子が含まれている粒径範囲のみの粒度分布と粒子濃度を求めることによって特徴づけられる。
【0011】
本発明の黄砂粒子の測定方法においては、上記のように集塵電極上に捕集した黄砂粒子を、レーザ回折・散乱式の粒度分布測定法を用いて粒度分布を求めることにより、高い分解能のもとに黄砂粒子の粒度分布と粒子濃度の測定を可能とするものである。
【0012】
すなわち、レーザ回折・散乱式の粒度分布測定においては、一般に、分散状態の被測定粒子群にレーザ光を照射して得られる回折・散乱光の空間強度分布を測定し、その光強度分布がミーの散乱理論ないしはフラウンホーファの回折理論に則ることを利用し、回折・散乱光の空間強度分布の測定結果からミーの散乱理論ないしはフラウンホーファの回折理論に基づく演算によって被測定粒子群の粒度分布を求める。このレーザ回折・散乱式の粒度分布測定によれば、被測定粒子群を分散させるための媒体中の濃度を適正範囲とすることによって、広い粒径範囲において高い分解能で粒度分布を求めることができる。
【0013】
しかしながら、大気中の黄砂粒子に直接的にレーザ光を照射して回折・散乱光を測定しようとしても、大気中における黄砂粒子の濃度が低すぎる関係上、粒度分布を求めるに十分な回折・散乱光を得ることができない。
【0014】
そこで、本発明においては、請求項1に係る発明を用いて、つまり大気を容器内に吸引してその容器内で黄砂粒子を含む粒子を帯電させて捕集電極上に捕集し、その捕集した粒子を、レーザ回折・散乱式の粒度分布測定に適した濃度範囲のもとに分散させてレーザ光を照射して回折・散乱光の空間強度分布を測定する。これにより、通常のレーザ回折・散乱式の粒度分布測定と同等の広い粒径範囲において高い分解能のもとに容器内に吸引した大気中に存在する粒子の粒度分布を測定することができる。そして、測定点における黄砂粒子の粒径範囲は、予備調査などによって判るので、その粒径範囲の粒度分布のみを測定すれば、その粒度分布を構成する粒子は黄砂粒子が支配的となり、従ってその測定結果は大気中に浮遊している黄砂粒子の粒度分布をほぼ正確に表すものとなる。
【0015】
また、その粒度分布測定に用いるレーザ回折・散乱式粒度分布測定装置を、あらかじめ濃度が既知の粒子でキャリブレーションを行っておくことにより、容器内に吸引した大気の量は、ポンプの流量とその駆動時間から容易に割り出すことができるので、大気中の黄砂粒子の濃度を求めることができる。
【0016】
【発明の実施の形態】
以下、図面を参照しつつ本発明の実施の形態について述べる。
図1は本発明の実施の形態の構成図であり、捕集装置10と、その捕集装置10により捕集した黄砂粒子の粒度分布並びに粒子濃度を測定するためのレーザ回折・散乱式粒度分布測定装置20とを併記して示す図である。
【0017】
捕集装置10は、捕集容器1とポンプ2、並びに捕集容器1内に配置された放電電極3および集塵電極4を主体として構成されている。開閉自在の蓋1aを備えた捕集容器1には、大気の流入口1bと、ポンプ(捕集用圧縮機)2の吸引口への連通口1cが形成されており、蓋1aを閉じた状態でポンプ2を駆動することにより、流入口1bを介して大気が捕集容器1内に吸引される。この捕集容器1内には、その上部に放電電極3が設けられているとともに、その放電電極3に対向してその下方には集塵電極4が配置されている。放電電極3には高圧電源5によって高圧電源が印加され、これによって放電電極3の近傍の空気が電離し、単極イオンが発生する。
【0018】
一方、集塵電極4は接地電位に接続され、この集塵電極と放電電極3の電位差により、単極イオンは集塵電極4に向けて移動し、その過程で捕集容器1内の大気中に含まれている黄砂などの浮遊粒子Pと接触してこれを帯電させる。帯電した黄砂を含む粒子Pは、同じく放電電極3と集塵電極4との電位差によって集塵電極4に向けて移動し、集塵電極4の表面に捕集される。
【0019】
集塵電極4として、平滑な平面を持つ金属などの導体、あるいは透明なガラスやプラスチックなどの表面に透明電極をコーティングしたものを用いると、捕集した黄砂粒子などの粒子Pは、容易に個々に抽出することができ、従って、顕微鏡で観察する場合、サンプリングが簡単で鮮明な像を得ることができる。また、各種分析機器による分析に供する場合においても、サンプリングや前処理が極めて容易となる。
【0020】
捕集した黄砂粒子の粒度分布を測定する場合、集塵電極4上に捕集した全ての粒子Pを、レーザ回折・散乱式粒度分布測定装置20による測定に供する。図1に示す例は、湿式測定を行う場合の例を示している。湿式測定の場合、分散槽21内に例えば蒸留水もしくは有機溶媒、またはこれらに界面活性剤等の分散剤を添加した液体からなる媒液Lを収容し、その媒液L中に集塵電極4上に捕集した粒子Pを投入して分散させる。
【0021】
分散槽21は、攪拌機21aおよび超音波振動子21bを備えているとともに、その底部には循環用配管21cの一端が連通しており、この循環用配管21cは循環用ポンプ21dを介してフローセル22の入口に連通し、更にそのフローセル22の出口から分散槽21の上方にまで至って開口している。また、この分散槽21の底部には、内容物を排出するための排出バルブ21eが設けられている。
【0022】
分散槽21内の媒液L中に粒子Pが投入された状態で、攪拌機21aおよび超音波振動子21bを駆動することにより、粒子Pは媒液L中に均一に分散するとともに、媒液L中に含まれている気泡が取り除かれる。媒液Lおよびそこに分散している粒子Pは、循環用ポンプ21dの駆動により循環用配管21cを介してフローセル22内を流れた後、分散槽21内に戻される。
【0023】
レーザ回折・散乱式粒度分布測定装置20の測定部は、上記したフローセル22と、そのフローセル22に対してレーザ光を照射する照射光学系23と、その照射光学系23からのレーザ光の回折・散乱光の空間強度分布を測定する測定光学系24を主体として構成されている。
【0024】
照射光学系23は、レーザ光源23a,集光レンズ23b、空間フィルタ23c、コリメートレンズ23dによって構成され、レーザ光源23aから出力されたレーザ光を平行光束としてフローセル22に照射する。このフローセル22に照射されたレーザ光は、その内部を流れる媒液L中の粒子Pによって回折・散乱を受ける。この回折・散乱光の空間強度分布は測定光学系24によって測定される。
【0025】
測定光学系24は、照射光学系23の光軸上にフローセル22を挟んで配置された集光レンズ24aおよびリングディテクタ24bと、その外側に配置された前方広角度散乱光センサ群24cと、フローセル22の側方および後方(照射光学系23側)に配置された側方/後方散乱光センサ群24dによって構成されている。リングディテクタ24bは、互いに異なる半径のリング状または1/2リング状もしくは1/4リング状の受光面を有する光センサを同心上に配置した光センサアレイであって、集光レンズ24aにより集光された前方所定角度以内の回折・散乱光の強度分布を検出することができる。従って、これらのセンサ群からなる測定光学系24により、フローセル22内の媒液L中に分散している粒子Pによる回折・散乱光の空間強度分布が、前方微小角度から後方に至る広い範囲で測定される。
【0026】
以上の測定光学系24による各回折・散乱角度ごとの光強度検出信号は、それぞれのアンプ並びにA−D変換器を有してなるデータサンプリング回路25によって増幅されたうえでデジタル化され、回折・散乱光の空間強度分布データとしてコンピュータ26に取り込まれる。
【0027】
コンピュータ26では、その回折・散乱光の空間強度分布を用いて、レーザ回折・散乱式の粒度分布測定において公知の、ミーの散乱理論およびフラウンホーファの回折理論に基づく演算手法により、レーザ光が回折・散乱した原因粒子であるフローセル22内の粒子Pの粒度分布を算出する。
【0028】
このとき、黄砂粒子の粒度分布を算出するためには、前もって黄砂粒子の粒径範囲を例えば顕微鏡観察等によって調査し、その粒径範囲をコンピュータ26に設定しておく。コンピュータ26では、この設定に基づき、集塵電極4上に捕集した大気中の全ての粒子Pの粒度分布のなかから、黄砂粒子の粒径範囲の粒度分布のみをピックアップし、その粒径範囲の分布データを正規化して、大気中の黄砂粒子の粒度分布として表示器(図示せず)に表示し、あるいはプリンタ(図示せず)により印字させる。
【0029】
また、測定に先立ち、単位体積中に含まれる個数が既知の標準粒子を用いて、散乱光の絶対強度を測定してキャリブレーションを行っておくことにより、粒子Pの回折・散乱光の絶対強度と、捕集容器1に送り込んだ大気の総量、つまりポンプ2の流量と駆動時間から、単位体積中に含まれる粒子径と個数の関係を求めることができる。その算出結果と、上記した黄砂粒子が含まれる粒径範囲とから、単位体積の大気に含まれる黄砂粒子の濃度を算出することができる。
【0030】
そして、以上の測定を、一定時間ごとに繰り返し行うことにより、連続的に大気中の黄砂粒子の状況を監視することができ、例えば黄砂粒子の濃度が、あらかじめ設定した濃度を越えた場合に、警報を発してその旨を報知することも可能となる。
【0031】
なお、以上の実施の形態においては、捕集電極4上に捕集した粒子Pを媒液L中に分散させて粒度分布の測定を行う例を示したが、本発明は、このような湿式測定によるレーザ回折・散乱式粒度分布測定のほか、媒液を使用しない、乾式測定によるレーザ回折・散乱式粒度分布測定を採用することもできる。
【0032】
乾式測定を採用する場合、集塵電極4として、図2にその模式的断面図を示すように、ガラスやプラスチックなどの透明板4aの表面に透明電極膜4bをコーティングしたものを用いることにより、粒子Pを捕集した集塵電極4に対して直接的にレーザ光を照射して、その回折・散乱光の空間強度分布を測定することが可能となり、その測定作業を容易化することができる。
【0033】
その場合のレーザ回折・散乱式粒度分布測定装置の要部構成例を図3に示す。この構成は、図1に示したフローセル22に代えて粒子Pを表面に捕集した透明板4aと透明電極膜4bとからなる集塵電極4を配置した点に特徴があり、媒液Lを用いないが故に分散槽21も不要となる。なお、測定光学系以下の構成は図1のものと全く同等である。このような乾式測定によっても、集塵電極4上の粒子Pが適宜の濃度(単位面積当たりの粒子Pの存在量)となっている限り、前記した湿式測定と同様に粒子Pによるレーザ光の回折・散乱光の空間強度分布を正確に測定することができ、先の実施の形態と同等の作用効果を奏することができる。
【0034】
また、このような透明板4aと透明電極4bとからなる集塵電極4を用いることにより、その集塵電極4に捕集したままで黄砂粒子の顕微鏡観察を行うことができる。
【0035】
【発明の効果】
以上のように、本発明の黄砂粒子の捕集方法によれば、大気中に浮遊する黄砂粒子を効率的に捕集することができるとともに、個々の黄砂粒子の抽出が簡単であるため、顕微鏡観察や各種分析機器による分析に容易に供することができる。
【0036】
また、本発明の黄砂粒子の測定方法によると、高い分解能のもとに黄砂粒子の粒度分布を測定することができるとともに、大気中の黄砂粒子の濃度を正確に測定することが可能となり、黄砂粒子の濃度変化の監視や、その結果に従って警報を発することも可能となる。
【図面の簡単な説明】
【図1】本発明の実施の形態の構成図であり、捕集装置10と、その捕集装置10により捕集した黄砂粒子の粒度分布並びに粒子濃度を測定するためのレーザ回折・散乱式粒度分布測定装置20とを併記して示す図である。
【図2】本発明の捕集装置10に用いることのできる集塵電極4の他の構成例を示す模式的断面図である。
【図3】図2の集塵電極4を用いる場合のレーザ回折・散乱式粒度分布測定装置の要部構成例を示す図である。
【符号の説明】
1 捕集容器
2 ポンプ
3 放電電極
4 集塵電極
5 高圧電源
6 接地電位
20 レーザ回折・散乱式粒度分布測定装置
21 分散槽
22 フローセル
23 照射光学系
24 測定光学系
25 データサンプリング回路
26 コンピュータ
P 黄砂粒子を含む粒子
[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for collecting yellow sand particles floating in the atmosphere and a method for measuring yellow sand particles collected by the method.
[0002]
[Prior art]
As for the yellow sand, the sand in the desert in the inner continent of China is soared by strong winds, swept away by the westerly winds over the sea, crosses the sea, and flies to Japan. The particle size of yellow sand varies from place to place, and is said to be about 20 to 30 μm in mainland China near the source and about 4 to 5 μm in Japan far from the source.
[0003]
In order to investigate the shape of yellow dust particles in the atmosphere, or to identify the chemical substances contained in them, the yellow dust particles are collected from the atmosphere using a filter and observed with a microscope. Or chemical analysis.
[0004]
As a device for measuring the particle size distribution of such yellow sand particles, a device based on the cascade impactor method has been conventionally put into practical use. The measuring device based on the cascade impactor system utilizes an impactor method in which particles are separated from a fluid by causing the fluid to collide with a collecting plate and abruptly change the flow direction. Impactors having sequentially changed diameters are connected in series in multiple stages, and the particle size of 50% collection efficiency in each stage is set as a representative diameter of each stage. This is for obtaining a particle size distribution.
[0005]
[Problems to be solved by the invention]
By the way, the method of observing the yellow sand particles floating in the atmosphere with a microscope or collecting them with a filter so as to supply them to various chemical analysis instruments is particularly difficult because the particles flying to Japan are as small as about 4 to 5 μm as described above. In addition, it is extremely difficult to extract individual particles alone, and when observing with a microscope, yellow sand particles attached to the filter are observed. Are unclear and difficult to observe. In addition, even when the collected yellow sand particles are supplied to various analytical instruments, it is difficult to extract the yellow sand particles alone from the filter. In this case, for example, in a fluorescent X-ray analyzer, it is difficult to irradiate only particles with X-rays, and there is a problem that analysis becomes substantially impossible or pretreatment is difficult.
[0006]
In addition, when measuring the particle size distribution of yellow sand particles using a conventional measuring device based on the conventional cascade impactor method, the resolution of the particle size is determined by the number of collecting plates in principle. It cannot be expected to measure the particle size distribution at.
[0007]
The present invention has been made in view of such circumstances, and efficiently collects yellow sand particles existing in the atmosphere, and observes the collected yellow sand particles with a microscope or supplies the collected yellow sand particles to various analytical instruments. It is an object of the present invention to provide a method for collecting yellow sand particles that is extremely easy to measure, and a method for measuring yellow sand particles capable of measuring the particle size distribution and particle concentration of the collected yellow sand particles with high resolution.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the method for collecting yellow sand particles of the present invention is a method for collecting yellow sand particles contained in the air, and the air is sucked into a container by a pump, and the dust is collected in the container. The suspended particles including yellow dust particles in the atmosphere are charged by the monopolar ions generated at the arranged discharge electrodes, and the charged particles are placed on the dust collection electrode having a potential difference with respect to the discharge electrodes in the container. Characterized by collecting.
[0009]
In the method for collecting yellow sand particles of the present invention, dust is collected by sucking air into a container in which a discharge electrode and a dust collecting electrode are disposed, and charging the yellow sand particles in the air with monopolar ions from the discharge electrodes. Since the yellow dust particles are collected on the surface of the electrode, the collected yellow sand particles can be easily extracted alone, and can be easily supplied to various analytical instruments, and observation with a microscope becomes easy.
[0010]
On the other hand, in the method for measuring yellow sand particles of the present invention, the spatial intensity distribution of diffracted / scattered light obtained by irradiating laser light while maintaining the particles collected by the method of claim 1 in a dispersed state is described. It is characterized by measuring and measuring the particle size distribution and particle concentration only in the particle size range containing yellow sand particles from the measurement results.
[0011]
In the method for measuring yellow sand particles of the present invention, the yellow sand particles collected on the dust collecting electrode as described above, by obtaining the particle size distribution using a laser diffraction and scattering type particle size distribution measuring method, high resolution. Based on this, it is possible to measure the particle size distribution and particle concentration of yellow sand particles.
[0012]
In other words, in the laser diffraction / scattering type particle size distribution measurement, generally, the spatial intensity distribution of the diffracted / scattered light obtained by irradiating a laser beam to the particles to be measured in a dispersed state is measured, and the light intensity distribution is measured. The particle size distribution of the group of particles to be measured is calculated from the measurement results of the spatial intensity distribution of the diffracted and scattered light by calculation based on Mie's scattering theory or Fraunhofer's diffraction theory, utilizing the scattering theory of Fraunhofer's diffraction theory. . According to this laser diffraction / scattering type particle size distribution measurement, the particle size distribution can be obtained with a high resolution over a wide particle size range by setting the concentration in the medium for dispersing the particle group to be measured in an appropriate range. .
[0013]
However, even when trying to measure the diffraction and scattered light by directly irradiating the yellow dust particles in the atmosphere with laser light, the diffraction and scattering is not enough to determine the particle size distribution because the concentration of yellow dust particles in the atmosphere is too low. I can't get light.
[0014]
Therefore, in the present invention, the invention according to claim 1 is used, that is, the air is sucked into the container, the particles including the yellow sand particles are charged in the container, and collected on the collecting electrode. The collected particles are dispersed in a concentration range suitable for laser diffraction / scattering type particle size distribution measurement, and irradiated with laser light to measure the spatial intensity distribution of the diffraction / scattered light. This makes it possible to measure the particle size distribution of the particles present in the air sucked into the container with high resolution in a wide range of particle size equivalent to that of the ordinary laser diffraction / scattering type particle size distribution measurement. Then, since the particle size range of the yellow sand particles at the measurement point can be determined by preliminary investigations and the like, if only the particle size distribution of the particle size range is measured, the particles constituting the particle size distribution are dominated by yellow sand particles, and The measurement result almost accurately represents the particle size distribution of the yellow sand particles floating in the atmosphere.
[0015]
In addition, by calibrating the laser diffraction / scattering type particle size distribution measuring device used for the particle size distribution measurement with particles having a known concentration in advance, the amount of air sucked into the container is determined by the flow rate of the pump and the Since it can be easily determined from the driving time, the concentration of yellow sand particles in the atmosphere can be obtained.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of an embodiment of the present invention. A collecting device 10 and a particle size distribution of a yellow sand particle collected by the collecting device 10 and a laser diffraction / scattering type particle size distribution for measuring the particle concentration. FIG. 2 is a diagram showing the measurement device 20 together.
[0017]
The collection device 10 mainly includes a collection container 1 and a pump 2, and a discharge electrode 3 and a dust collection electrode 4 arranged in the collection container 1. A collection container 1 having an openable and closable lid 1a is formed with an air inlet 1b and a communication port 1c to a suction port of a pump (collection compressor) 2, and the lid 1a is closed. By driving the pump 2 in this state, the atmosphere is sucked into the collection container 1 through the inlet 1b. In the collection container 1, a discharge electrode 3 is provided on an upper portion thereof, and a dust collection electrode 4 is disposed below and opposite to the discharge electrode 3. A high-voltage power supply 5 is applied to the discharge electrode 3 by a high-voltage power supply 5, whereby air near the discharge electrode 3 is ionized and monopolar ions are generated.
[0018]
On the other hand, the dust collecting electrode 4 is connected to the ground potential, and the unipolar ions move toward the dust collecting electrode 4 due to the potential difference between the dust collecting electrode 4 and the discharge electrode 3. In contact with the floating particles P such as yellow sand contained in the water. The particles P containing the charged yellow sand move toward the dust collecting electrode 4 due to the potential difference between the discharge electrode 3 and the dust collecting electrode 4, and are collected on the surface of the dust collecting electrode 4.
[0019]
When a conductor such as a metal having a flat surface or a transparent electrode coated on a surface such as transparent glass or plastic is used as the dust collecting electrode 4, the collected particles P such as yellow sand particles can be easily separated. Therefore, when observed with a microscope, a clear image can be obtained with simple sampling. Also, in the case where analysis is performed by various analytical instruments, sampling and preprocessing are extremely easy.
[0020]
When measuring the particle size distribution of the collected yellow sand particles, all the particles P collected on the dust collecting electrode 4 are subjected to measurement by the laser diffraction / scattering type particle size distribution measuring device 20. The example shown in FIG. 1 shows an example in which wet measurement is performed. In the case of the wet measurement, for example, distilled water or an organic solvent, or a medium L made of a liquid to which a dispersant such as a surfactant is added is contained in the dispersion tank 21, and the dust collecting electrode 4 is contained in the medium L. The particles P collected on top are introduced and dispersed.
[0021]
The dispersion tank 21 includes a stirrer 21a and an ultrasonic vibrator 21b, and one end of a circulation pipe 21c communicates with the bottom thereof. The circulation pipe 21c is connected to a flow cell 22 via a circulation pump 21d. , And further open from the outlet of the flow cell 22 to above the dispersion tank 21. At the bottom of the dispersion tank 21, a discharge valve 21e for discharging the contents is provided.
[0022]
By driving the stirrer 21a and the ultrasonic vibrator 21b in a state where the particles P are charged into the medium L in the dispersion tank 21, the particles P are uniformly dispersed in the medium L and the medium L Bubbles contained therein are removed. The medium liquid L and the particles P dispersed therein flow through the flow cell 22 through the circulation pipe 21c by driving the circulation pump 21d, and then return to the dispersion tank 21.
[0023]
The measuring unit of the laser diffraction / scattering type particle size distribution measuring device 20 includes the above-described flow cell 22, an irradiation optical system 23 for irradiating the flow cell 22 with laser light, and a diffracting and diffracting laser beam from the irradiation optical system 23. The measurement optical system 24 mainly measures the spatial intensity distribution of the scattered light.
[0024]
The irradiation optical system 23 includes a laser light source 23a, a condenser lens 23b, a spatial filter 23c, and a collimator lens 23d, and irradiates the laser beam output from the laser light source 23a as a parallel light beam to the flow cell 22. The laser light applied to the flow cell 22 is diffracted and scattered by the particles P in the medium L flowing therein. The spatial intensity distribution of the diffracted / scattered light is measured by the measuring optical system 24.
[0025]
The measuring optical system 24 includes a condenser lens 24a and a ring detector 24b disposed on the optical axis of the irradiation optical system 23 with the flow cell 22 interposed therebetween, a front wide-angle scattered light sensor group 24c disposed outside thereof, It is composed of a side / backward scattered light sensor group 24d disposed on the side and rear side of the irradiation optical system 22 (on the side of the irradiation optical system 23). The ring detector 24b is an optical sensor array in which optical sensors having ring-shaped or 1 / 2-ring-shaped or 1 / 4-ring-shaped light receiving surfaces having different radii are arranged concentrically, and is condensed by a condensing lens 24a. It is possible to detect the intensity distribution of the diffracted / scattered light within the specified forward angle. Therefore, the spatial intensity distribution of the diffracted / scattered light by the particles P dispersed in the medium L in the flow cell 22 is widened by the measuring optical system 24 composed of these sensor groups in a wide range from the front small angle to the rear. Measured.
[0026]
The light intensity detection signal for each diffraction / scattering angle by the measurement optical system 24 is amplified and digitized by a data sampling circuit 25 having an amplifier and an AD converter. The data is taken into the computer 26 as spatial intensity distribution data of the scattered light.
[0027]
The computer 26 uses the spatial intensity distribution of the diffracted / scattered light to diffract the laser light by a calculation method based on Mie's scattering theory and Fraunhofer's diffraction theory, which is well-known in laser diffraction / scattering type particle size distribution measurement. The particle size distribution of the particles P in the flow cell 22 as the scattered cause particles is calculated.
[0028]
At this time, in order to calculate the particle size distribution of the yellow sand particles, the particle size range of the yellow sand particles is checked in advance by, for example, microscopic observation or the like, and the particle size range is set in the computer 26 in advance. Based on this setting, the computer 26 picks up only the particle size distribution of the yellow sand particles from the particle size distribution of all the particles P in the air collected on the dust collecting electrode 4, and Is displayed on a display (not shown) as a particle size distribution of yellow sand particles in the atmosphere, or printed by a printer (not shown).
[0029]
Prior to measurement, the absolute intensity of the scattered light of the particle P is measured by performing calibration by measuring the absolute intensity of the scattered light using standard particles whose number contained in a unit volume is known. The relationship between the particle size and the number of particles contained in a unit volume can be determined from the total amount of air sent into the collection container 1, that is, the flow rate and the driving time of the pump 2. From the calculation result and the particle size range including the yellow sand particles described above, the concentration of the yellow sand particles contained in the unit volume of the atmosphere can be calculated.
[0030]
Then, by repeatedly performing the above measurement at regular intervals, it is possible to continuously monitor the status of yellow dust particles in the atmosphere.For example, when the concentration of yellow dust particles exceeds a preset concentration, It is also possible to issue an alarm and notify that effect.
[0031]
Note that, in the above embodiment, an example in which the particles P collected on the collection electrode 4 are dispersed in the medium L and the particle size distribution is measured has been described. In addition to laser diffraction / scattering type particle size distribution measurement by measurement, laser diffraction / scattering type particle size distribution measurement by dry measurement without using a liquid medium can also be adopted.
[0032]
When dry measurement is adopted, as shown in a schematic cross-sectional view of FIG. 2, the dust collecting electrode 4 is formed by coating a transparent plate 4a such as glass or plastic with a transparent electrode film 4b coated on the surface thereof. It is possible to directly irradiate the laser beam to the dust collecting electrode 4 that has collected the particles P and measure the spatial intensity distribution of the diffracted and scattered light, thereby facilitating the measurement operation. .
[0033]
FIG. 3 shows a configuration example of a main part of a laser diffraction / scattering type particle size distribution measuring device in that case. This configuration is characterized in that instead of the flow cell 22 shown in FIG. 1, a dust collecting electrode 4 composed of a transparent plate 4a and a transparent electrode film 4b that collect particles P on the surface is arranged. Since it is not used, the dispersion tank 21 is not required. The configuration below the measuring optical system is completely equivalent to that of FIG. Even in such a dry measurement, as long as the particles P on the dust collecting electrode 4 have an appropriate concentration (the amount of the particles P per unit area), the laser light generated by the particles P is the same as in the wet measurement described above. The spatial intensity distribution of the diffracted / scattered light can be accurately measured, and the same effect as that of the above embodiment can be obtained.
[0034]
In addition, by using the dust collecting electrode 4 including the transparent plate 4a and the transparent electrode 4b, the yellow sand particles can be observed with a microscope while being collected by the dust collecting electrode 4.
[0035]
【The invention's effect】
As described above, according to the method for collecting yellow sand particles of the present invention, it is possible to efficiently collect the yellow sand particles floating in the atmosphere and to easily extract individual yellow sand particles. It can be easily used for observation and analysis by various analytical instruments.
[0036]
According to the method for measuring yellow sand particles of the present invention, the particle size distribution of the yellow sand particles can be measured under high resolution, and the concentration of the yellow sand particles in the atmosphere can be accurately measured. It is also possible to monitor the change in the concentration of particles and issue an alarm according to the result.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an embodiment of the present invention, wherein a collecting device 10 and a laser diffraction / scattering type particle size for measuring a particle size distribution and a particle concentration of yellow sand particles collected by the collecting device 10; FIG. 2 is a diagram showing a distribution measuring device 20 together.
FIG. 2 is a schematic cross-sectional view showing another configuration example of the dust collecting electrode 4 that can be used in the collecting device 10 of the present invention.
FIG. 3 is a diagram showing an example of a configuration of a main part of a laser diffraction / scattering type particle size distribution measuring device when the dust collecting electrode 4 of FIG. 2 is used.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Collection container 2 Pump 3 Discharge electrode 4 Dust collection electrode 5 High voltage power supply 6 Ground potential 20 Laser diffraction / scattering type particle size distribution measuring device 21 Dispersion tank 22 Flow cell 23 Irradiation optical system 24 Measurement optical system 25 Data sampling circuit 26 Computer P Yellow sand Particles containing particles

Claims (2)

大気中に含まれる黄砂粒子を捕集する方法であって、
大気をポンプにより容器内に吸引するとともに、その容器内に配置した放電電極で発生させた単極イオンにより、大気中の黄砂粒子を含む浮遊粒子を帯電させ、その帯電粒子を、上記容器内で放電電極に対して電位差が与えられた集塵電極上に捕集することを特徴とする黄砂粒子の捕集方法。
A method for collecting yellow sand particles contained in the atmosphere,
The air is sucked into the container by the pump, and the floating particles including the yellow sand particles in the air are charged by the monopolar ions generated by the discharge electrodes arranged in the container, and the charged particles are charged in the container. A method for collecting yellow sand particles, wherein the dust is collected on a dust collecting electrode provided with a potential difference with respect to a discharge electrode.
請求項1に記載の方法により捕集した粒子を分散状態に維持した状態で、レーザ光を照射して得られる回折・散乱光の空間強度分布を測定し、その測定結果から、黄砂粒子が含まれている粒径範囲のみの粒度分布と粒子濃度を求めることを特徴とする黄砂粒子の測定方法。In a state where the particles collected by the method according to claim 1 are maintained in a dispersed state, a spatial intensity distribution of diffraction / scattered light obtained by irradiating a laser beam is measured, and from the measurement result, yellow sand particles are included. A method for measuring yellow sand particles, wherein a particle size distribution and a particle concentration in only a specified particle size range are obtained.
JP2002209713A 2002-01-21 2002-07-18 Collecting method and measuring method of yellow sand particle Pending JP2004053357A (en)

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JP2002209713A JP2004053357A (en) 2002-07-18 2002-07-18 Collecting method and measuring method of yellow sand particle
US10/322,677 US6807874B2 (en) 2002-01-21 2002-12-19 Collecting apparatus of floating dusts in atmosphere
KR1020030046419A KR100554531B1 (en) 2002-07-18 2003-07-09 Collecting and measuring method of yellow sand particles
CNB031475213A CN1288433C (en) 2002-07-18 2003-07-09 Method and its device for collecting yellow sand and its measuring method and device
US10/882,621 US6923848B2 (en) 2002-01-21 2004-07-02 Collecting apparatus of floating dusts in atmosphere
US11/048,895 US7041153B2 (en) 2002-01-21 2005-02-03 Method of measuring floating dusts

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JP2004170287A (en) * 2002-11-21 2004-06-17 Shimadzu Corp Collecting device for suspended particulate matter in atmosphere
JP2004177347A (en) * 2002-11-28 2004-06-24 Shimadzu Corp Capturing device and measuring device for suspended particulate matter in atmosphere
JP2008527366A (en) * 2005-01-14 2008-07-24 ユニデータ ヨーロッパ リミテッド Particulate matter detector
JP2012518186A (en) * 2009-02-18 2012-08-09 バッテル メモリアル インスティチュート Small area electrostatic aerosol collector

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