JP4790206B2

JP4790206B2 - Prefilter manufacturing method

Info

Publication number: JP4790206B2
Application number: JP2003138481A
Authority: JP
Inventors: 敏孔戸澗; 弘堀上; 拓哉堂元; 敏馬場; 文男中島; 仁新沼; 克博大野
Original assignee: Tokyo Electric Power Co Inc; Nippon Muki Co Ltd
Current assignee: Nippon Muki Co Ltd; Tokyo Electric Power Company Holdings Inc
Priority date: 2003-05-16
Filing date: 2003-05-16
Publication date: 2011-10-12
Anticipated expiration: 2023-05-16
Also published as: JP2004337759A

Description

【０００１】
【発明の属する技術分野】
本発明は中・高性能フィルタのプレフィルタの製造方法に関し、特に、ガスタービン用吸気フィルタに使用されるプレフィルタの製造方法に関する。
【０００２】
【従来の技術】
従来において、図５に示すように、中・高性能フィルタのプレフィルタとして、長尺帯状の濾材１１に補強体１２を接着して波形状に折り畳んだ積層濾材１３の上下２箇所に、くし歯状間隔保持部１４Ｂ，１７Ｂを設けた一対のくし歯状スタビライザ１４，１７を流出側及び流入側のそれぞれに設け、波形状の間隔を保持した前記積層濾材１３を、前後面に所要形状の複数の開口１５ｄを形成する開口面サポート部１５ｃを形成した紙製の箱状外枠１５，１６内に収容固定したプレフィルタ１０が使用されている（特許文献１参照）。
【０００３】
【特許文献１】
特開２０００−１１７０３４号公報（第３頁、図１）
【０００４】
【発明が解決しようとする課題】
しかしながら、前記特許文献１のプレフィルタは、積層濾材の上下２箇所に一対のスタビライザを設けて積層濾材の波形状の間隔を保持しているため、積層濾材の変形が少ないという利点を有するものの、通常、ガスタービン吸気フィルタの１次フィルタとして用いられる大きさのプレフィルタ内に収容される波形状の積層濾材の折山数は２２程度であり、濾材面積が小さく、プレフィルタの粉塵保持量がそれほど大きくないため、フィルタ寿命が短寿命であるという問題があった。
また、前後面に形成した開口面サポート部と前記くし歯状スタビライザによりデッドスペースが形成され、空気が通過する有効面積が小さくなり、結果としてプレフィルタの濾材の利用率が低下し、濾材の実際面積から想定されるよりも圧力損失が大きくなり、フィルタ寿命が短くなるという問題があった。
そこで、本発明は、前記叙述の問題点に鑑みて、プレフィルタの濾材の有効面積を拡大して、フィルタの長寿命化が可能なプレフィルタの製造方法を提供することを目的とする。
【０００５】
【課題を解決するための手段】
本発明のガスタービン用吸気フィルタに使用されるプレフィルタの製造方法は、前記目的を達成するべく、請求項１に記載の通り、前後面に所要形状の開口を備える開口面サポートをそれぞれ形成して成る外枠内に、長尺帯状の厚さが４〜８ｍｍの不織布濾材の一面に補強体を添設して波形状に折り畳んだ積層濾材が固定収容されたガスタービン用吸気フィルタに使用されるプレフィルタの製造方法において、前記外枠の横寸法を（Ａ）とし、奥行寸法を（Ｈ）とし、横断面積を（ＡＨ）とした場合の、前記濾材の長さ（Ｌ）と前記外枠の横断面積（ＡＨ）との比（Ｌ／ＡＨ）が７８〜９５ｍ^-1 、前記開口面サポートの開口率が８０〜９０％、前記外枠の横断面積が横寸法５９４〜６１０ｍｍ×奥行寸法７０〜１２０ｍｍ、前記積層濾材の折山数（正数）が２４〜２８であるようにすることを特徴とする。
【０００６】
【発明の実施の形態】
本発明の製造方法によるプレフィルタ１は、図１に示すように、前後面に所要形状の開口を備える開口面サポートをそれぞれ形成して成る外枠５，６内に、長尺帯状の濾材２の一面に補強体３を添設して波形状に折り畳んだ積層濾材４が固定収容されており、前記濾材２の長さと前記外枠５，６の横断面積との比が７８〜９５ｍ^−１と成っている。
前記外枠５，６によって外形が構成されるプレフィルタ１の横寸法を（Ａ）とし、奥行寸法を（Ｈ）とし、波形状の積層濾材４の一山の片側の長さを（Ｌo）とした場合、濾材の長さ（Ｌ）は、（１）式によって表され、濾材の長さ（Ｌ）に対する外枠５，６の横断面積（ＡＨ）との比は（２）式によって表される。
Ｌ＝Ｌo ×２×積層濾材の山数（１）
濾材の長さに対する外枠の横断面積の比＝Ｌ／ＡＨ（２）
積層濾材は、プレフィルタの流入側から流出側に亘るように折り畳まれて波形状に形成されるため、濾材の長さと外枠の横断面積との比を規定することにより、プレフィルタの圧力損失が大きくなるという問題を生じることなく、粉塵保持量を大きくすることができる適当な範囲内で濾材面積を拡大することができ、圧力損失の増大によって生じるプレフィルタの短寿命化を防止することができる。
プレフィルタの濾材の長さと外枠の横断面積との比を７８〜９５ｍ^−１としたのは、前記比が７８ｍ^−１未満であると、外枠内に波形状に折り畳んで収納する濾材の濾材面積を拡大することができず、プレフィルタの粉塵保持量が少なくなるという問題があり、前記比が９５を超えると、波形状の積層濾材が密になりすぎて、プレフィルタの圧力損失が大きくなるという問題があるからである。
具体的には、例えば、外枠の横断面積が横寸法５９４〜６１０ｍｍ×奥行寸法７０〜１２０ｍｍの場合、濾材の長さと外枠の横断面積との比を７８〜９５ｍ^−１とするためには、該外枠内に収納する濾材の最適長さは、３．２４〜６．９５ｍとなる。また、空気の流入側から流出側に亘るように前記濾材を波形状に折り畳んだ場合、一山の底辺に対して高さ（外枠の奥行寸法）が十分に大きいため、一山の片側の長さ（Ｌo）は、前記外枠の奥行寸法に近似して計算することができ、前記寸法の外枠に最適な長さの前記濾材を波形状に折り畳んだ場合の積層濾材の折山数（正数）は、２４〜２８となる。
【０００７】
前記濾材２としては、不織強化綿（コットン）とポリエステル繊維等の合成繊維の混合不織布や合成繊維単独の不織布を使用できる。
前記濾材２は、厚さが４〜８ｍｍであることが好ましい。濾材２の厚さが４ｍｍ未満では、粉塵保持量が少ないのでプレフィルタの長寿命化が図れないからである。また濾材２の厚さが８ｍｍを超えるとフィルタの圧力損失が高くなる問題があるからである。
【０００８】
前記補強体３としては、亜鉛メッキ鉄線等の金網、トリカルネット等の合成樹脂製網、不織布等が使用できる。特に補強体が合成樹脂製網や、不織布とすれば、焼却減容して廃棄することも可能である。
【０００９】
前記濾材２と前記補強体３は、波形状にプリーツ加工する前に濾材２の流出側に補強体３を接着剤により積層固定している。
【００１０】
前記外枠５，６としては、飲料水パック等に使用される耐水性紙、コートボール紙（片面を樹脂コートした板紙２枚を樹脂コート面が外側となるように接着積層して耐水性としたものが特によい）等が使用できる。その他アルミ、ステンレス等の金属板等を用いることができる。また、外枠５，６は流入側、流出側共に積層濾材４をサポートするように菱形等の所望形状の開口を複数備えた開口面サポート部５ｃ（６ｃ）から成る開口面サポートが設けられている。
【００１１】
図２は、プレフィルタ１の外枠５（６）の展開図であり、外枠５（６）は、コートボール紙製の一枚板を折り曲げ加工することにより形成している。即ち、前記一枚板の隣接する２角のコーナ５ｂ（６ｂ）を矩形状に切り欠き、他の２角のコーナに、該コーナ部分を折り曲げ可能とする耳部５ａ（６ａ）を形成し、コーナとコーナの間の辺を垂直に折り曲げ加工して壁部とし、一面が解放した状態の箱形状の外枠５（６）を形成している。前記耳部５ａ（６ａ）は、隣接した前記壁部に重ね合わされるように折り曲げている。二つの箱形状の外枠５（６）の解放面同士を対向させると共に、二つの外枠５（６）の耳部５ａ（６ａ）が非対称となるように、外枠５（６）を組み合わせて、内部に濾材が収納可能となる箱状の外枠５（６）を形成している。尚、耳部５ａ（６ａ）が非対称となるように外枠５（６）を組み合わせたのは、エアリークを防止するためである。
【００１２】
外枠５（６）を形成する一枚板の中央面には、空気を通過させるための開口５ｄ（６ｄ）を形成しており、開口５ｄ（６ｄ）は、前記外枠５（６）内に収容した濾材の破損を防ぐ開口面サポート部５ｃ（６ｃ）を設けた開口面サポートとなっている。
【００１３】
外枠５（６）の開口面サポートは、開口率が８０〜９０％となるように形成している。開口面サポートの開口率が８０％未満であると、濾材２に空気が通過しないデッドスペースが大きくなり、外枠５（６）内に収容した濾材２の利用率が低下し、濾材２の実際面積から想定されるよりも圧力損失が大きくなるからである。また、開口面サポートの開口率が９０％を超えると、外枠５（６）内に収容した積層濾材４をサポートすることができず、濾材２に破損を生じるおそれがあるからである。
【００１４】
開口面サポートの開口率を８０〜９０％とするために、前記図２に示すように、箱状の外枠５（６）の対向する隅角部と隅角部を結ぶ二つの対角線状の開口面サポート部５ｃ（６ｃ）を設けることが好ましい。その他、例えば図３に示すように、外枠を構成する一辺の略中央部から隣接する他の一辺の略中央部に向けて四つの斜線状の開口面サポート部５ｃ’（６ｃ’）を設けることが好ましい。尚、開口面サポート部の形状は、濾材のサポート性、枠強度、濾過面積確保等を考慮し、開口面サポートの開口率が８０〜９０％であれば、前記図示の例に限らない。また、外枠は、コートボール紙、アルミ、ステンレス等の金属板等を用いることが好ましい。
【００１５】
図１に示すように、プレフィルタ１は、長尺帯状の濾材２と補強体３とを接着し、一定の折山高さ、所定の折山数となるよう波形状に折り畳まれた積層濾材４を前記外枠５（６）内に収容し、前記積層濾材４と外枠５（６）とは、互いにデンプンのり等の接着剤により接着して気密にシールされている。
【００１６】
前記積層濾材４の波形状の間隔を保持するために、波形状の積層濾材４の頂部全体を帯状にサポートする帯状サポート部１４Ａ（１７Ａ）と、該積層濾材４の折り畳まれた間隔を保持するくし歯状間隔保持部１４Ｂ（１７Ｂ）とから形成される紙製スタビライザ１４（１７）を、積層濾材４の流入側或いは流出側にそれぞれ設けることも可能である。前記スタビライザ１４（１７）には、前記外枠５（６）と同様に、飲料水パック等に使用される耐水性紙、コートボール等を使用できる。その他アルミ、ステンレス等の金属板等を使用することができる。スタビライザ１４（１７）を用いる場合であっても、外枠５（６）の開口面サポートの開口率が８０〜９０％を満たしていることが好ましい。図４に示す紙製スタビライザ１４（１７）は、左右対称な形状に打ち抜いた一枚板を対角線からＶ字状に二つ折りにしたものを使用している。尚、スタビライザ１４（１７）のくし歯状間隔保持部１４Ｂ（１７Ｂ）の歯高さ１４ｂ（１７ｂ）、歯間隔１４ｃ（１７ｃ）、歯底部幅１４ｄ（１７ｄ）、歯上部幅１４ｅ（１７ｅ）は、積層濾材４のジグザグ状の間隔を保持可能となるように、積層濾材４の波形状に合わせて適宜設定している。スタビライザ１４（１７）は、積層濾材４及び外枠５（６）に接着剤により接着固定することが可能である。
【００１７】
【実施例】
次に、本発明プレフィルタの製造方法の実施例１〜８及び比較例１〜６について説明する。尚、本発明はこの実施例に限定されるものではない。
（実施例１）
厚さ１ｍｍのコートボール紙製の縦寸法５９４ｍｍ×横寸法５９４ｍｍ×奥行寸法９５ｍｍの大きさの箱状の外枠に、ポリエステル繊維製の長尺帯状の濾材と亜鉛メッキ鉄線製の金網から成る補強体を接着剤で接着して厚さ７ｍｍとし、折山高さが９５ｍｍとなるように波形状に折り畳んだ積層濾材を収容固定してプレフィルタを形成した。前記濾材の長さと外枠の横断面積との比を８０ｍ^−１とした。また、積層濾材の折山数は２４であった。前記プレフィルタの開口面サポートは、図５に示す構造と同様に、基本開口が菱形となる開口面サポート部を設け、積層濾材の上下２箇所に、くし歯状間隔保持部を備えた一対のくし歯状スタビライザを流出側及び流入側のそれぞれに設けた。前記プレフィルタの開口面サポートの開口率は６０％である。
【００１８】
（実施例２〜４）
濾材の長さと外枠の横断面積との比を８４ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２５となる以外は実施例１と同様のものを実施例２とし、濾材の長さと外枠の横断面積との比を８７ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２６となる以外は実施例１と同様のものを実施例３とし、濾材の長さと外枠の横断面積との比を９４ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２８となるもの以外は実施例１と同様のものを実施例４とした。
【００１９】
（実施例５）
開口面サポートとして、図１及び図２に示す構造と同様に、外枠の対向する隅角部と隅角部を結ぶ二つの対角線状の開口面サポート部を設けたものを用いた以外は、実施例１と同様の厚み及び大きさの外枠内に、実施例１と同様の積層濾材を収容固定してプレフィルタを形成した。前記濾材の長さと外枠の横断面積との比を８０ｍ^-1とした。前記大きさの外枠に前記長さの濾材を波形状に折り畳んで収納すると、積層濾材の折山数は２４となった。前記プレフィルタの開口面サポートの開口率は８３％である。尚、本実施例のプレフィルタはスタビライザを用いていない。
【００２０】
（実施例６〜８）
濾材の長さと外枠の横断面積との比を８４ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２５となる以外は実施例５と同様のものを実施例６とし、濾材の長さと外枠の横断面積との比を８７ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２６となる以外は実施例５と同様のものを実施例７とし、濾材の長さと外枠の横断面積との比を９４ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２８となるもの以外は実施例５と同様のものを実施例８とした。
【００２１】
（比較例１〜３）
濾材の長さと外枠の横断面積との比は、前記比が７８ｍ^-1未満となる７４ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２２となる以外は、実施例１と同様のものを比較例１とし、濾材の長さと外枠の横断面積との比が７８ｍ^-1未満となる７７ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２３となる以外は、実施例１と同様のものを比較例２とし、濾材の長さと外枠の横断面積との比が９５ｍ^-1を超える１０１ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が３０となる以外は、実施例１と同様のものを比較例３とした。
【００２２】
（比較例４〜６）
濾材の長さと外枠の横断面積との比は、前記比が７８ｍ^-1未満となる７４ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２２となる以外は、実施例５と同様のものを比較例４とし、濾材の長さと外枠の横断面積との比が７８ｍ^-1未満となる７７ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が２３となる以外は、実施例５と同様のものを比較例５とし、濾材の長さと外枠の横断面積との比が９５ｍ^-1を超える１０１ｍ^-1とし、前記外枠内に収容した積層濾材の折山数が３０となる以外は、実施例５と同様のものを比較例６とした。
【００２３】
次に、このようにして得られた実施例１〜８及び比較例１〜６のプレフィルタの圧力損失と粉塵保持量を評価した。結果を表１に示す。
［粉塵保持量］
ＪＩＳＢ９９０８（形式２）により、各プレフィルタに、風量５６ｍ³／ｍｉｎで、ＪＩＳ１５種粉体を半年〜１年間通過させた時の初期から前記期間経過後の各プレフィルタの粉塵保持量（ｇ／台）を粉塵保持容量試験装置により測定した。
判定基準：粉塵保持量が６００ｇ／台以上の場合を○、粉塵保持量が６００ｇ／台未満の場合を×とした。
［圧力損失］
ＪＩＳＢ９９０８（形式２）により、各プレフィルタに、風量５６ｍ³／ｍｉｎで、空気を通過させた時の各プレフィルタの圧力損失を粉塵保持容量試験装置により測定した。
判定基準：圧力損失が６０Ｐａ以下の場合を○、圧力損失が６１〜６５Ｐａの場合を△、圧力損失が６５Ｐａを超えた場合を×とした。
［総体評価］
判定基準：粉塵保持量及び圧力損失が共に○の場合を優良◎、粉塵保持量が○且つ圧力損失が△の場合を良○、粉塵保持量又は圧力損失のどちらか一方が×の場合を否×とした。
【００２４】
【表１】

【００２５】
表１に示す結果から以下のことが分かった。
実施例１〜８の濾材の長さと外枠の横断面積との比（Ｌ／ＡＨ）が７８〜９５ｍ^-1を満たす各プレフィルタは、圧力損失が６５Ｐａ以下と小さく、粉塵保持量が６００ｇ／台と大きく、圧力損失及び粉塵保持量が共に良好であり、総体評価が良○又は優良◎であった。前記結果から一定の横断面積を有する外枠内に、前記比を満たす長さの濾材を波形状の折り畳んで収容すると、プレフィルタの圧力損失が大きくなるという問題を生じることなく、濾材面積を拡大することができ、粉塵保持量を増大してプレフィルタの長寿命化を図ることが可能であることが確認できた。
前記実施例１〜４と実施例５〜８について、濾材の長さと外枠の横断面積との比が同じプレフィルタごとに、開口率が６０％であるプレフィルタと開口率が８３％であるプレフィルタを比較すると、開口率が８３％と大きいプレフィルタの方が、開口率が６０％と小さいプレフィルタよりも圧力損失が小さく、粉塵保持量が大きくなっていた。この結果により、濾材長さと外枠の横断面積との比が同一である場合に、開口面サポートの開口率を８０〜９０％と大きくした場合は、空気を通過させる有効面積を拡大することができ、濾材の利用率を向上して、圧力損失の上昇を抑えることが可能であることが確認できた。
比較例１、２、４、５のように、濾材の長さと外枠の横断面積との比が７８ｍ^-1未満のプレフィルタは、圧力損失が６６Ｐａ以下であるものの、塵埃保持量が５５０ｇ／台以下と低く、総体評価が否×であった。この結果から、前記比が７８ｍ^-1未満のプレフィルタは、濾材面積が小さいため、粉塵保持量が低くなり、フィルタの長寿命化が困難であることが確認できた。
また、比較例３、６のように、濾材の長さと外枠の横断面積との比が９５ｍ^-1を超えているプレフィルタは、塵埃保持量が７５０台／ｇ以上と大きいものの、圧力損失が６７Ｐａ以上と大きく、総体評価が否×であった。この結果から、前記比が９５ｍ^-1を超えているプレフィルタは、積層濾材の波形状の間隔が密になりすぎて圧力損失が大きくなり、フィルタの長寿命化が困難であることが確認できた。
【００２６】
【発明の効果】
本発明のプレフィルタの製造方法は、以下の効果を有している。
（１）本発明のプレフィルタの製造方法は、濾材の長さと外枠の横断面積との比が７８〜９５ｍ^−１となるようにしたため、圧力損失を大きくすることなく、粉塵保持量を大きくすることができる適当な範囲内で濾材面積を拡大することができ、フィルタ寿命を従来のプレフィルタの半年間から１年間に長寿命化することができる。
（２）また、濾材の長さと外枠の横断面積との比が同一であるプレフィルタにおいて、前記プレフィルタの開口面サポートの開口率が８０〜９０％と、開口面サポートの開口率を大きくした場合には、従来のプレフィルタよりも空気が通過しないデッドスペースを少なくすることができ、濾材の有効活用により、プレフィルタの圧力損失の上昇を押さえることができる。
（３）更に、本発明のプレフィルタの製造方法は長寿命化を実現したため、使用済みプレフィルタ（産業廃棄物）の量を低減することができ、プレフィルタの交換費用を低減することができる。
【図面の簡単な説明】
【図１】本発明の製造方法によるプレフィルタの一部破断部を含む斜視図。
【図２】外枠の展開図。
【図３】他の外枠の実施例を示す展開図。
【図４】スタビライザの展開図。
【図５】従来のプレフィルタの一部破断部を含む斜視図。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a prefilter for a medium / high performance filter, and more particularly to a method for manufacturing a prefilter used for an intake filter for a gas turbine.
[0002]
[Prior art]
Conventionally, as shown in FIG. 5, as a pre-filter of a medium / high performance filter, comb teeth are formed at two upper and lower portions of a laminated filter medium 13 that is bonded to a long band-shaped filter medium 11 and folded into a wave shape. A pair of comb-

shaped stabilizers

14 and 17 provided with the shape

interval holding portions

14B and 17B are provided on the outflow side and the inflow side, respectively, and the laminated filter medium 13 holding the wave-like interval is provided with a plurality of required shapes on the front and rear surfaces. A prefilter 10 is used that is housed and fixed in a paper box-like

outer frame

15 or 16 in which an opening surface support portion 15c for forming an opening 15d is formed (see Patent Document 1).
[0003]
[Patent Document 1]
JP 2000-117034 (3rd page, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, although the prefilter of Patent Document 1 has a pair of stabilizers at two upper and lower portions of the laminated filter medium and maintains the interval between the wave shapes of the laminated filter medium, it has the advantage that the deformation of the laminated filter medium is small. Usually, the number of folds of the corrugated laminated filter medium accommodated in the prefilter of the size used as the primary filter of the gas turbine intake filter is about 22, the filter medium area is small, and the dust holding amount of the prefilter is small. Since it is not so large, there is a problem that the filter life is short.
In addition, a dead space is formed by the opening surface support portions formed on the front and rear surfaces and the comb-shaped stabilizer, and the effective area through which air passes is reduced. As a result, the utilization rate of the filter medium of the prefilter is reduced, and the actual condition of the filter medium is reduced. There was a problem that the pressure loss was larger than expected from the area, and the filter life was shortened.
In view of the above-described problems, an object of the present invention is to provide a method for manufacturing a prefilter capable of extending the effective area of the filter material of the prefilter and extending the life of the filter .
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a method for producing a prefilter used for a gas turbine intake filter according to the present invention forms an opening surface support having openings of a required shape on the front and rear surfaces, respectively. Is used for a gas turbine intake filter in which a laminated filter medium is fixed and accommodated in a corrugated shape by attaching a reinforcing body to one surface of a non-woven filter medium having a long belt thickness of 4 to 8 mm. In the method for manufacturing a prefilter, the length (L) of the filter medium and the outer dimension when the lateral dimension of the outer frame is (A), the depth dimension is (H), and the cross-sectional area is (AH). The ratio (L / AH) to the cross-sectional area (AH) of the frame is 78 to 95 m ⁻¹ , the aperture ratio of the opening support is 80 to 90%, and the cross-sectional area of the outer frame is the horizontal dimension 594 to 610 mm × depth dimension. 70-120mm, folding of the laminated filter media The number (positive number) is characterized in that so is 24-28.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the prefilter 1 according to the manufacturing method of the present invention has a long belt-like filter medium 2 in

outer frames

5 and 6 each formed with an opening surface support having openings of a required shape on the front and rear surfaces. A laminated filter medium 4 that is folded in a wave shape with a reinforcing body 3 attached to one surface is fixedly accommodated, and the ratio of the length of the filter medium 2 to the cross-sectional area of the

outer frames

5 and 6 is 78 to 95 m ^−1. It consists of.
The lateral dimension of the pre-filter 1 whose outer shape is constituted by the

outer frames

5 and 6 is (A), the depth dimension is (H), and the length of one side of the peak of the corrugated laminated filter medium 4 is (Lo). In this case, the length (L) of the filter medium is expressed by the expression (1), and the ratio of the cross-sectional area (AH) of the

outer frames

5 and 6 to the length (L) of the filter medium is expressed by the expression (2). Is done.
L = Lo x 2 x number of layers of laminated filter media (1)
Ratio of cross-sectional area of outer frame to length of filter medium = L / AH (2)
Since the laminated filter medium is folded into a wave shape from the inflow side to the outflow side of the prefilter, the pressure loss of the prefilter can be determined by defining the ratio between the length of the filter medium and the cross-sectional area of the outer frame. The filter medium area can be expanded within an appropriate range in which the amount of retained dust can be increased without causing the problem of increasing the size of the filter, and the prefilter can be prevented from shortening its life due to increased pressure loss. it can.
The ratio of the cross-sectional area of the length and the outer frame of the filter medium of the prefilter was 78～95M ^-1, the ratio is less than 78m ^-1, the filter medium for storing folded into a wave shape in an outer frame There is a problem that the filter medium area cannot be expanded and the amount of dust retained in the prefilter is reduced. When the ratio exceeds 95, the corrugated laminated filter medium becomes too dense, and the pressure loss of the prefilter increases. This is because there is a problem of becoming larger.
Specifically, for example, when the cross-sectional area of the outer frame is a horizontal dimension of 594 to 610 mm x a depth dimension of 70 to 120 mm, in order to set the ratio of the length of the filter medium and the cross-sectional area of the outer frame to 78 to 95 m ⁻¹ The optimum length of the filter medium housed in the outer frame is 3.24 to 6.95 m. In addition, when the filter medium is folded into a wave shape so as to extend from the air inflow side to the outflow side, the height (depth dimension of the outer frame) is sufficiently large with respect to the bottom of the mountain, so The length (Lo) can be calculated by approximating the depth dimension of the outer frame, and the number of folds of the laminated filter medium when the filter medium having the optimum length for the outer frame of the dimension is folded into a wave shape. (Positive number) is 24 to 28.
[0007]
As the filter medium 2, a mixed nonwoven fabric of synthetic fibers such as non-woven reinforced cotton (cotton) and polyester fibers or a nonwoven fabric composed of synthetic fibers alone can be used.
The filter medium 2 preferably has a thickness of 4 to 8 mm. This is because if the thickness of the filter medium 2 is less than 4 mm, the amount of dust retained is small, so that the life of the prefilter cannot be extended. Further, if the thickness of the filter medium 2 exceeds 8 mm, there is a problem that the pressure loss of the filter increases.
[0008]
As the reinforcing body 3, a wire net such as galvanized iron wire, a synthetic resin net such as tricarnet, a non-woven fabric, or the like can be used. In particular, if the reinforcing body is made of a synthetic resin net or a non-woven fabric, the volume can be reduced by incineration and discarded.
[0009]
The filter medium 2 and the reinforcing body 3 are laminated and fixed with an adhesive on the outflow side of the filter medium 2 before pleating into a wave shape.
[0010]
As the

outer frames

5 and 6, water-resistant paper used for drinking water packs, coated cardboard (two paperboards coated with resin on one side are bonded and laminated so that the resin-coated surface is on the outside and water-resistant Can be used). Other metal plates such as aluminum and stainless steel can be used. The

outer frames

5 and 6 are provided with an opening surface support composed of an opening surface support portion 5c (6c) having a plurality of openings of a desired shape such as a rhombus so as to support the laminated filter medium 4 on both the inflow side and the outflow side. Yes.
[0011]
FIG. 2 is a development view of the outer frame 5 (6) of the pre-filter 1. The outer frame 5 (6) is formed by bending a single coated cardboard sheet. That is, the adjacent corners 5b (6b) of the single plate are cut out in a rectangular shape, and the corners 5a (6a) are formed in the other corners so that the corners can be bent. A side wall between the corners is bent vertically to form a wall portion, and a box-shaped outer frame 5 (6) in a state where one surface is released is formed. The ear portion 5a (6a) is bent so as to overlap the adjacent wall portion. Combine the outer frames 5 (6) so that the release surfaces of the two box-shaped outer frames 5 (6) face each other and the ears 5a (6a) of the two outer frames 5 (6) are asymmetric. Thus, a box-shaped outer frame 5 (6) that can accommodate the filter medium is formed inside. The reason why the outer frame 5 (6) is combined so that the ear portion 5a (6a) is asymmetric is to prevent air leakage.
[0012]
An opening 5d (6d) for allowing air to pass through is formed in the central surface of the single plate forming the outer frame 5 (6). The opening 5d (6d) is formed in the outer frame 5 (6). It is an opening surface support provided with an opening surface support portion 5c (6c) that prevents the filter medium accommodated in the container from being damaged.
[0013]
The opening surface support of the outer frame 5 (6) is formed so that the opening ratio is 80 to 90%. When the aperture ratio of the opening surface support is less than 80%, a dead space in which air does not pass through the filter medium 2 becomes large, the utilization rate of the filter medium 2 accommodated in the outer frame 5 (6) decreases, and the filter medium 2 is actually used. This is because the pressure loss is larger than expected from the area. Further, if the opening ratio of the opening surface support exceeds 90%, the laminated filter medium 4 accommodated in the outer frame 5 (6) cannot be supported, and the filter medium 2 may be damaged.
[0014]
In order to set the aperture ratio of the opening surface support to 80 to 90%, as shown in FIG. 2, two diagonal lines connecting the corner portions of the box-shaped outer frame 5 (6) are opposed to each other. It is preferable to provide the opening surface support part 5c (6c). In addition, for example, as shown in FIG. 3, four oblique opening surface support portions 5c ′ (6c ′) are provided from a substantially central portion of one side constituting the outer frame toward a substantially central portion of the other adjacent side. It is preferable. The shape of the opening surface support portion is not limited to the example shown in the drawings as long as the opening ratio of the opening surface support is 80 to 90% in consideration of the supportability of the filter medium, the frame strength, the filtration area securing, and the like. The outer frame is preferably a coated cardboard, a metal plate such as aluminum or stainless steel, or the like.
[0015]
As shown in FIG. 1, a prefilter 1 is a laminated filter medium 4 in which a long band-shaped filter medium 2 and a reinforcing body 3 are bonded and folded into a wave shape so as to have a constant fold height and a predetermined number of folds. In the outer frame 5 (6), and the laminated filter medium 4 and the outer frame 5 (6) are adhered to each other with an adhesive such as starch paste and hermetically sealed.
[0016]
In order to maintain the wavy interval of the laminated filter medium 4, the band-shaped support part 14 </ b> A (17 </ b> A) that supports the entire top of the wave-shaped laminated filter medium 4 in a band shape and the folded interval of the laminated filter medium 4 are maintained. It is also possible to provide a paper stabilizer 14 (17) formed from the comb-like interval holding portion 14B (17B) on the inflow side or the outflow side of the laminated filter medium 4, respectively. As the stabilizer 14 (17), water-resistant paper used for drinking water packs, court balls, and the like can be used similarly to the outer frame 5 (6). Other metal plates such as aluminum and stainless steel can be used. Even when the stabilizer 14 (17) is used, it is preferable that the opening ratio of the opening surface support of the outer frame 5 (6) satisfies 80 to 90%. The paper stabilizer 14 (17) shown in FIG. 4 uses a single plate punched into a symmetrical shape and folded in half from a diagonal line into a V shape. The tooth height 14b (17b), tooth spacing 14c (17c), tooth bottom width 14d (17d), and tooth top width 14e (17e) of the comb-like interval holding portion 14B (17B) of the stabilizer 14 (17) are as follows. The laminated filter medium 4 is appropriately set according to the wave shape of the laminated filter medium 4 so that the zigzag interval of the laminated filter medium 4 can be maintained. The stabilizer 14 (17) can be bonded and fixed to the laminated filter medium 4 and the outer frame 5 (6) with an adhesive.
[0017]
【Example】
Next, Examples 1 to 8 and Comparative Examples 1 to 6 of the method for producing a prefilter of the present invention will be described. In addition, this invention is not limited to this Example.
Example 1
Reinforcement consisting of a long belt-like filter medium made of polyester fiber and a wire mesh made of galvanized iron wire on a box-like outer frame made of coated cardboard with a thickness of 1 mm, a vertical dimension of 594 mm, a horizontal dimension of 594 mm, and a depth dimension of 95 mm The body was bonded with an adhesive to a thickness of 7 mm, and a pre-filter was formed by accommodating and fixing the laminated filter medium folded into a wave shape so that the fold height was 95 mm. The ratio of the length of the filter medium to the cross-sectional area of the outer frame was 80 m ⁻¹ . Moreover, the number of folds of the laminated filter medium was 24. As in the structure shown in FIG. 5, the prefilter opening surface support is provided with a pair of opening surface support portions provided with rhomboid basic openings and provided with comb-like spacing holding portions at two upper and lower portions of the laminated filter medium. Comb-shaped stabilizers were provided on each of the outflow side and the inflow side. The aperture ratio of the opening surface support of the prefilter is 60%.
[0018]
(Examples 2 to 4)
The ratio between the length of the filter medium and the cross-sectional area of the outer frame is 84 m ^−1, and the same number as that of Example 1 is set to Example 2 except that the number of folds of the laminated filter medium accommodated in the outer frame is 25. The ratio between the length of the filter medium and the cross-sectional area of the outer frame is 87 m ^−1, and the same number as that of Example 1 is set to Example 3 except that the number of folds of the laminated filter medium accommodated in the outer frame is 26. Example 4 is the same as Example 1 except that the ratio of the length of the filter medium to the cross-sectional area of the outer frame is 94 m ^-1 and the number of folds of the laminated filter medium accommodated in the outer frame is 28. did.
[0019]
(Example 5)
Like the structure shown in FIG.1 and FIG.2 as an opening surface support, except using what provided the two diagonal opening surface support parts which connect the corner part which the outer frame opposes, and a corner part, A prefilter was formed by accommodating and fixing the same laminated filter medium as in Example 1 in an outer frame having the same thickness and size as in Example 1. The ratio between the length of the filter medium and the cross-sectional area of the outer frame was 80 m ⁻¹ . When the filter medium of the length was folded into a wave shape and stored in the outer frame of the size, the number of folds of the laminated filter medium was 24. The aperture ratio of the opening surface support of the prefilter is 83%. Note that the prefilter of this embodiment does not use a stabilizer.
[0020]
(Examples 6 to 8)
The ratio between the length of the filter medium and the cross-sectional area of the outer frame is 84 m ^−1, and the same number as that of Example 5 is set to Example 6 except that the number of folds of the laminated filter medium accommodated in the outer frame is 25. The ratio between the length of the filter medium and the cross-sectional area of the outer frame is 87 m ^−1, and the same number as that of Example 5 is set to Example 7 except that the number of folds of the laminated filter medium accommodated in the outer frame is 26. Example 8 is the same as Example 5 except that the ratio of the length of the filter medium to the cross-sectional area of the outer frame is 94 m ^-1 and the number of folds of the laminated filter medium accommodated in the outer frame is 28. did.
[0021]
(Comparative Examples 1-3)
The ratio between the length of the filter medium and the cross-sectional area of the outer frame is 74 m ⁻¹ where the ratio is less than 78 m ^−1, and the number of folds of the laminated filter medium accommodated in the outer frame is 22, 1 is set as Comparative Example 1, the ratio of the length of the filter medium to the cross-sectional area of the outer frame is set to 77 m ^{−1 which is} less than 78 m ^−1, and the number of folds of the laminated filter medium accommodated in the outer frame is 23. the addition made, as Comparative example 2 the same as in example 1, and 101 m ^-1 the ratio of the cross-sectional area of the length of the filter media and the outer frame is greater than 95 m ^-1, the laminated filter material which is accommodated in the outer frame Comparative Example 3 was the same as Example 1 except that the number of folds was 30.
[0022]
(Comparative Examples 4-6)
The ratio between the length of the filter medium and the cross-sectional area of the outer frame is 74 m ⁻¹ where the ratio is less than 78 m ^−1, and the number of folds of the laminated filter medium accommodated in the outer frame is 22, 5 is set as Comparative Example 4, the ratio of the length of the filter medium to the cross-sectional area of the outer frame is set to 77 m ^{−1 which is} less than 78 m ^−1, and the number of folds of the laminated filter medium accommodated in the outer frame is 23 the addition made, as Comparative example 5 the same as in example 5, and 101 m ^-1 the ratio of the cross-sectional area of the length of the filter media and the outer frame is greater than 95 m ^-1, the laminated filter material which is accommodated in the outer frame Comparative Example 6 was the same as Example 5 except that the number of folds was 30.
[0023]
Next, the pressure loss and dust holding amount of the prefilters of Examples 1 to 8 and Comparative Examples 1 to 6 thus obtained were evaluated. The results are shown in Table 1.
[Dust retention]
According to JIS B 9908 (Type 2), the amount of dust retained in each pre-filter after the passage of the period from the initial stage when JIS 15 seed powder is passed through each pre-filter at an air volume of 56 m ³ / min for half a year to one year ( g / unit) was measured with a dust holding capacity tester.
Judgment criteria: A case where the dust holding amount was 600 g / unit or more was evaluated as “◯”, and a case where the dust holding amount was less than 600 g / unit was evaluated as “X”.
[Pressure loss]
According to JIS B 9908 (Type 2), the pressure loss of each prefilter when air was passed through each prefilter at an air volume of 56 m ³ / min was measured with a dust holding capacity tester.
Judgment criteria: ◯ when the pressure loss is 60 Pa or less, Δ when the pressure loss is 61 to 65 Pa, and x when the pressure loss exceeds 65 Pa.
[Overall evaluation]
Judgment criteria: Excellent when the dust holding amount and pressure loss are both ◎ Excellent, when the dust holding amount is ◯ and the pressure loss is △, and when either the dust holding amount or the pressure loss is × X.
[0024]
[Table 1]

[0025]
The results shown in Table 1 revealed the following.
Each prefilter in which the ratio (L / AH) of the length of the filter medium of Examples 1 to 8 and the cross-sectional area of the outer frame satisfies 78 to 95 m ⁻¹ has a small pressure loss of 65 Pa or less, and the dust holding amount is 600 g / The table was large, both the pressure loss and the amount of dust retained were good, and the overall evaluation was good or excellent. From the above results, when a filter medium having a length satisfying the above ratio is accommodated in an outer frame having a constant cross-sectional area, the filter medium area is expanded without causing a problem that the pressure loss of the prefilter increases. It was confirmed that it was possible to increase the dust holding amount and extend the life of the prefilter.
For Examples 1-4 and Examples 5-8, for each prefilter having the same ratio of the length of the filter medium and the cross-sectional area of the outer frame, the prefilter with an aperture ratio of 60% and the aperture ratio is 83%. When comparing the prefilters, the prefilter having a large aperture ratio of 83% had a smaller pressure loss and a larger dust holding amount than the prefilter having a small aperture ratio of 60%. As a result, when the ratio of the length of the filter medium and the cross-sectional area of the outer frame is the same, when the aperture ratio of the aperture support is increased to 80 to 90%, the effective area through which air can pass can be expanded. It was confirmed that it was possible to improve the utilization rate of the filter medium and suppress the increase in pressure loss.
As in Comparative Examples 1, 2, 4, and 5, the prefilter having a ratio of the length of the filter medium to the cross-sectional area of the outer frame of less than 78 m ⁻¹ has a pressure loss of 66 Pa or less, but has a dust holding amount of 550 g / It was as low as below the table, and the overall evaluation was no. From this result, it was confirmed that the pre-filter having the ratio of less than 78 m ⁻¹ has a small filter medium area, so that the dust holding amount is low and it is difficult to extend the life of the filter.
Further, as in Comparative Examples 3 and 6, the prefilter in which the ratio of the length of the filter medium to the cross-sectional area of the outer frame exceeds 95 m ⁻¹ has a large dust holding amount of 750 units / g or more, but the pressure loss Was as large as 67 Pa or more, and the overall evaluation was negative. From this result, it can be confirmed that the prefilter having the ratio exceeding 95 m ⁻¹ has a too narrow wave-like interval between the laminated filter media, and the pressure loss increases, and it is difficult to extend the life of the filter. It was.
[0026]
【The invention's effect】
The method for producing a prefilter of the present invention has the following effects.
(1) In the method for producing a prefilter of the present invention, the ratio of the length of the filter medium to the cross-sectional area of the outer frame is set to 78 to 95 m ⁻¹ , so that the amount of retained dust is increased without increasing the pressure loss. The filter medium area can be increased within an appropriate range, and the filter life can be extended from half a year to one year of the conventional prefilter.
(2) In the prefilter having the same ratio between the length of the filter medium and the cross-sectional area of the outer frame, the aperture ratio of the aperture support of the prefilter is 80 to 90%, and the aperture ratio of the aperture support is increased. In this case, the dead space through which air does not pass can be reduced as compared with the conventional prefilter, and an increase in the pressure loss of the prefilter can be suppressed by effectively using the filter medium.
(3) Furthermore, since the prefilter manufacturing method of the present invention achieves a long service life, the amount of used prefilter (industrial waste) can be reduced, and the replacement cost of the prefilter can be reduced. .
[Brief description of the drawings]
FIG. 1 is a perspective view including a partially broken portion of a prefilter according to a manufacturing method of the present invention .
FIG. 2 is a development view of the outer frame.
FIG. 3 is a development view showing another embodiment of the outer frame.
FIG. 4 is a development view of a stabilizer.
FIG. 5 is a perspective view including a partially broken portion of a conventional prefilter.

Claims

In the outer frame formed by opening surface supports each having an opening of the required shape on the front and rear surfaces, a reinforcing body is attached to one surface of a non-woven filter medium having a long belt shape thickness of 4 to 8 mm and folded into a wave shape. In the manufacturing method of the pre-filter used for the gas turbine intake filter in which the laminated filter medium is fixedly accommodated, the lateral dimension of the outer frame is (A), the depth dimension is (H), and the transverse area is (AH). , The ratio (L / AH) of the length (L) of the filter medium to the cross-sectional area (AH) of the outer frame is 78 to 95 m ⁻¹ ,
The aperture ratio of the opening surface support is 80 to 90%, the cross-sectional area of the outer frame is horizontal dimension 594 to 610 mm × depth dimension 70 to 120 mm, and the number of folds (positive number) of the laminated filter medium is 24-28. A method for producing a prefilter, characterized in that