JP2005013794A

JP2005013794A - Heatable filter press

Info

Publication number: JP2005013794A
Application number: JP2003178839A
Authority: JP
Inventors: Yoshio Sawada; 芳夫沢田; Eiichi Shimizu; 栄一清水
Original assignee: Ishigaki Co Ltd
Current assignee: Ishigaki Co Ltd
Priority date: 2003-06-24
Filing date: 2003-06-24
Publication date: 2005-01-20

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heatable filter press the cake dehydrating property of which can be improved by heating the cake in a filtration chamber and in which the moisture content of the dehydrated cake can be lowered by sending air of normal temperature to the filtration chamber at the same time. <P>SOLUTION: This heatable filter press is constituted so that metallic filter media (2, 4) are respectively stretched on a heating plate (1) formed into a planar shape and on a filtration bed (3a) of a filter plate (3), the plate (1) is brought into direct contact with the cake in the filtration chamber (5) and an air supplying hole (1e) communicating with the chamber (5) is arranged on the plate (1). The plate (1) is brought into direct contact with the concentrated sludge or cake so that the viscosity and resistivity of the sludge or cake can be lowered. The air of normal temperature is circulated by convection to displace the wet air generated in the bed (3a) so that the cake can be dried. Since both sides of the plate (1) are used, heat conductivity can be made higher and short-time treatment can be attained. The metallic filter medium to be used in this filter press is hardly deteriorated by heating and even if this medium is not washed, the filtration characteristics of this medium are hardly deteriorated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、上水汚泥、下水汚泥及び産業排水汚泥等の処理に適したフイルタープレスに関し、特に、フイルタープレスのろ過室の濃縮汚泥やケーキを加熱して脱水性を改善し、脱水ケーキの含水率を低下させる加温式フイルタープレスの改良に関する。
【０００２】
【従来の技術】
従来、ろ過圧を掛けられるフイルタープレスは、非圧縮性のあるケーキほど有利であり固液分離装置として多く採用されている。また、ダイアフラムろ板を利用したフイルタープレスは圧搾性があり、ろ過性の悪いケーキに対しても使用が可能であるが、脱水機単独ではケーキ内部にある内部保留水分が完全に除去できない。この水分除去を効率的に行うために、フイルタープレス内部の温度を高め、ケーキを間接加熱する装置が提案されている。例えば、加温ろ板とダイアフラムろ板にろ布を吊設し、ろ過室に負圧手段を併設して、ケーキの加熱と吸引により脱水ケーキの含水率を低減させる装置も、特許文献１に記載してあるように公知である。
【０００３】
【特許文献１】
特開２０００−３３４２２１号公報（段落番号００３１乃至段落番号００３４、図３）
【０００４】
【発明が解決しようとする課題】
従来の脱水処理中に脱水ケーキを加熱するフイルタープレスは、処理能力の向上と含水率の低下が可能となるものであるが、ケーキと加熱プレートとの間にろ布が介在しており、加熱プレートからケーキへの熱伝導効率が悪くなり、乾燥に時間がかかっていた。また、樹脂性のろ布は熱に弱く、ダイアフラムろ板で加圧されるため、早期に能力低下と劣化が生じていた。ケーキの両面がろ布に接触しているため、ケーキの剥離性も悪いと言う短所がある。また、脱水ケーキを加熱しながらろ過室を負圧とし、ケーキ中の水分を低減させる装置にあっては、真空度を高めることにより沸点が下がり、ケーキ中の水分が蒸発しやすくなるものであるが、肝心のケーキに熱を伝える輻射効果が減少し、期待する程の結果が得られない。ろ過室の密閉シールが完全でなく、負圧設備も大きくなる欠点がある。この発明は、金属性の加熱プレートを直接ケーキに接触させ、同時に、ろ過室に空気を対流させて湿潤空気を排出し、熱効率とケーキの剥離性を向上させる加温式フイルタープレス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】
この発明の要旨は、加熱プレートとろ過床を凹面状に形成したろ板を交互に並列してろ過室を形成し、加熱プレートとろ板を開板してろ過室の乾燥ケーキを排出させるフイルタープレスにおいて、平板状に形成した加熱プレートとろ板のろ過床に金属ろ材を張設して、ろ過室のケーキに直接接触させると共に、加熱プレートに、ろ過室に連通する空気の給気孔を設けたもので、加熱プレートが直接濃縮汚泥やケーキ接触して粘性と比抵抗を低下させ、ろ過性を改善する。空気の対流により、ろ過床に発生した湿潤空気を置換させてケーキを乾燥させることができる。そして、ろ布を介して加温するよりもケーキの乾燥が速く、短時間処理が可能となる。また、金属ろ材は、加温によるろ材の劣化がなく、ろ材を洗浄しなくてもろ過特性の低下がない。
【０００６】
ろ過室のケーキの加熱手段は、加熱プレートのろ過床の内部に複数の加熱パイプを配設したもので、全面を加熱して加熱プレートの両面を利用するので熱伝導が良い。金属ろ材を張設したろ板の代わりに、芯板にダイアフラムを張設したダイアフラムろ板とし、ダイアフラムの表面を平板状に形成して、直接ケーキに接触させてもよく、ダイアフラムろ板は圧搾水を使うため、熱による劣化がなく、ろ過室のケーキの高圧搾が可能となる。また、芯板に張設するダイアフラムに、ろ液溝を有するろ過床を形成し、そのろ過床にろ布を吊設してもよいもので、ろ過室のケーキの両側からろ液が排出され、圧搾によりケーキが塑性変形してろ布から剥離されやすくなる。加熱プレート側のケーキの加熱面は粉状化して容易にケーキ剥離ができる。ダイアフラムろ板のろ過面に吊設するろ布も、ダイアフラムろ板の圧搾水で冷却されて劣化することがない。
【０００７】
【発明の実施の形態】
この発明に係る装置は上記のように構成してあり、加熱プレートとろ板で形成したろ過室に汚泥を圧入すると、汚泥は濃縮されながらろ過室に充満する。引き続き汚泥を圧入しながら、加熱プレートに蒸気または熱風を供給して濃縮汚泥を加熱すると、ウエッジワイヤーを張設した加熱プレートは直接ケーキに接触して乾燥が行われ、濃縮汚泥の粘性と比抵抗が低下して脱水性が改善され、剥離性も良くなる。そして、ろ過室に供給した空気は、金属ろ材を張設した加熱プレートのろ過床で対流を起こし、ろ過床に発生した湿潤空気を置換させてケーキを乾燥し、金属ろ材やろ板のろ過面に残存する水滴を排出する。ろ過室の乾燥されたケーキは、加熱面のケーキ表面が粉状化されて加熱プレートから剥離し易くなり、脱水時間の短縮と含水率の低いケーキを得ることができる。
【０００８】
加熱プレートに対設するろ板をダイアフラムろ板とすれば、ケーキはダイアフラムで圧搾されてケーキの含水率がさらに低下し、圧搾されたケーキ表面は塑性変形してダイアフラムから剥離されやすくなる。またダイアフラムろ板のろ過面にろ布を吊設してもよく、圧搾によりろ布からケーキが剥離される。ダイアフラムろ板とろ布は圧搾水を使うため熱による劣化がない。そして、ろ板と加熱プレートを開板すれば、加熱プレート側のケーキの加熱面は粉状化して容易に金属ろ材からケーキは剥離され、ケーキは自重によりろ過室外に排出される。圧搾時間の短縮と含水率の低いケーキを得ることができる。
【０００９】
【実施例】
この発明に係るフイルタープレスを図面に基づき詳述すると、先ず、図１はろ過室を形成した加熱プレートとろ板の縦断面図であって、加熱プレート１にろ液排出溝を有するろ過床１ａが形成してあり、このろ過床１ａに金属ろ材としてウエッジワイヤー２が張設してある。加熱プレート１に張設したウエッジワイヤー２のろ過面と周部のシール部１ｂの厚みが平板状に形成してある。加熱プレート１に対設するろ板３は、その内側に凹面状に形成してろ液排出溝を有するろ過床３ａと、周面に額縁状のシール部３ｂが設けてある。このろ板３のろ過床３ｂにもウエッジワイヤー４が張設してある。加熱プレート１とろ板３にろ液の排出用のろ過床１ａ、３ａを設けたので、分離されたろ液の排出が速く行われ、汚泥の固液分離の時間が短縮される。
【００１０】
図１に示すように、加熱プレート１とろ板３にそれぞれ張設したウエッジワイヤー２、４はその拡開された楔状の先端部をろ過床１ａ、３ａに当設してあり、ろ液を加熱プレート１とろ板３のろ過床１ａ、３ａに排出しやすくしてある。図２は加熱プレートまたはろ板の平面図であって、加熱プレート１とろ板３に張設するウエッジワイヤー２、４は、スリット２ａ、４ａ側をろ過面としてあり、そのスリット２ａ、４ａを上下方向に配設してある。この加熱プレート１とろ板３が多数並列してあり、加熱プレート１とろ板３を閉板した時に、前後の加熱プレート１とろ板３でろ過室５を形成する。なお、加熱プレート１とろ板３に張設するウエッジワイヤー２、４はパンチングメタルとしてもよいもので、金属ろ材は熱伝導が良く、乾燥が速く短時間処理が可能となる。また、金属ろ材は、加温によるろ材の劣化がなく、洗浄しなくてもろ過特性の劣化がない。
【００１１】
図１に示すように、加熱プレート１とろ板３の上部シール部１ｂ、３ｂに原液供給路１ｃ、３ｃが設けてあり、並列した加熱プレート１とろ板３を閉板した時に、加熱プレート１とろ板３の上部シール部１ｂ、３ｂに原液供給路１ｃ、３ｃが連通するようにしてある。この原液供給路１ｃ、３ｃは、ろ板３の給液孔３ｄを介してウエッジワイヤー４の前面に連通され、加熱プレート１とろ板３の間のろ過室５に原液を圧入する。この発明の実施例では、０．７〜１．５ＭＰａの圧力で原液を圧入する。また、ろ板３の下部のシール部３ｂにろ過床３ａに連通するろ液排出孔３ｅが設けてあり、ろ液を機外に排出させる。加熱プレート１の下部のシール部１ｂにもウエッジワイヤー２の裏面のろ過床１ａに連通するろ液排出孔１ｄが設けてあり、ウエッジワイヤー２で固液分離を行ったろ液をろ液排出孔１ｄからも排出する。
【００１２】
図３は加熱プレートの平面図であって、加熱プレート１の内部には複数本の加熱パイプ６…が配設してあり、加熱プレート１に設けた供給口６ａから蒸気または熱風を供給し、加熱プレート１の排出口６ｂから排出させる。この発明の実施例では、加熱プレート１を７５〜８５℃に加熱して、そのろ過床１ａから熱伝導によりウエッジワイヤー２に伝達し、脱水ケーキを直接加熱する。濃縮汚泥やケーキの粘性と比抵抗が低下して脱水性が改善される。ろ過室５のケーキは、加熱面のケーキ表面が粉状化されて加熱プレート１に張設したウエッジワイヤー２から剥離し易くなる。加熱プレート１の両面を利用するので熱効率が高く、加熱プレート１から熱伝導により加熱されたウエッジワイヤー２が直接ケーキに接触して乾燥が早く行われる。
【００１３】
図３に示すように、加熱プレート１の上部シール部１ｂにろ過床１ａに連通する給気孔１ｅが設けてあり、加熱プレート１とろ板３で形成したろ過室５に、この発明の実施例では、空気量が１５０ＮＬ／ｍｉｎ／ｍ^２の常温空気（１０〜２０℃）を５０分間供給する。ろ過室５に供給した空気は、ウエッジワイヤー２の裏面とろ過床１ａの間に空気を対流させて、加熱プレート１のろ液排出孔１ｄから排出する。ケーキから水分が蒸発して飽和状態となった湿潤空気を置換させ、乾燥空気を供給してケーキ中の水分を蒸発しやすくする。ウエッジワイヤー２や加熱プレート１のろ過床１ａに残存する水滴も吹飛ばし、脱水時間の短縮と含水率の低いケーキを得ることができる。ろ過室５に供給する空気は季節により変動するもので、ケーキの性状も勘案して、常温空気の供給時間を適宜設定すればよいものである。
【００１４】
ろ過室５に生成された乾燥ケーキは、加熱プレート１とろ板３を開板すれば、加熱プレート１側のケーキの加熱面は粉状化して容易にウエッジワイヤー２から剥離される。そして、ケーキは自重によりろ板３に張設するウエッジワイヤー４から剥離され、スリット４ａに沿って落下する。なお、ウエッジワイヤー２、４をパンチングメタルとしても、直接ろ過室５のケーキに接触し、熱伝達効率がよい。また、加熱プレート１に設けた常温空気の給気孔１ｅは、ろ板３に配設してもよい。必要に応じて、熱プレート１の上方に公知の昇降自在なスクレーパを配設し、加熱プレート１とろ板３のウエッジワイヤー２、４に摺設させてもよいものである。
【００１５】
図４は、ダイアフラムろ板を用いた他の実施例であって、加熱プレート１とダイアフラムろ板７が交互に並列してあり、ダイアフラムろ板７は、凹面状に形成した芯板８に表面９ａを平板状としたダイアフラム９が張設してある。ダイアフラムろ板７の原液供給路７ａの前面に給液板１４が止着してあり、原液はダイアフラムろ板７の原液供給路７ａから給液板１４の給液孔１４ａを通ってろ過室５ａに供給されて固液分離が行われる。原液の圧入完了後、芯板８のシール部８ａに設けた圧力水孔８ｂからダイアフラム９の裏面に高圧水を供給して、ケーキを圧搾し、加熱プレート１のろ液排出孔１ｄから分離したろ液を排出させる。圧搾されるケーキ表面は、塑性変形してダイアフラム９から剥離されやすくなる。ダイアフラムろ板７に張設したダイアフラム９は、圧搾用の水を使うため熱による劣化がない。
【００１６】
図５はダイアフラムろ板の前面にろ布を吊設した他の実施例であって、加熱プレート１に対設するダイアフラムろ板１０は、凹面状に形成した芯板１１にろ液溝を有するダイアフラム１２が張設してある。ダイアフラムろ板１０の前後にろ布１３、１３が吊設してあり、ろ布１３の上部に給液板１４が止着してある。給液板１４は加熱プレート１とダイアフラムろ板１０に設けた原液の原液供給路１ｃ、１０ａに対設してある。原液は原液供給路１ｃ、１０ａから給液板１４の給液孔１４ａを通り、ろ過室５ｂに圧入する。芯板１１のシール部１１ａにダイアフラム１２の裏面に連通する圧力水孔１１ｂと、ろ布１３の裏面のダイアフラムろ板１０のろ液溝に連通するろ液排出孔１１ｃが設けてある。ケーキとろ布１３の接触面は圧搾するダイアフラムろ板１０側の一面のみであり、ろ布１３もダイアフラムろ板１０の圧搾水で冷やされて劣化することがない。ろ過室５ｂに生成された乾燥ケーキは、加熱プレート１とダイアフラムろ板１０を開板すれば、ダイアフラム１２に圧搾されて塑性変形しているケーキは、その自重によりダイアフラム１２やろ布１３から剥離される。
【００１７】
【表１】

【００１８】
実験例１
通気時間とケーキ水分の低減率の実験を、加熱プレートを設けたフイルタープレスで行った。先ず、４％の浄水スラッジを０．７ＭＰａの圧力でフイルタープレスに圧入し、２０分後に浄水スラッジの圧入を停止した。その時の脱水ケーキの含水率は９０％であった。次に、ろ過室のケーキをダイアフラムで１．５ＭＰａで圧搾してこの状態を保ちながら、加熱プレートを７５℃と８５℃で加熱した時のケーキ水分と、７５℃と８５℃でろ過板を加熱しながら、空気量が１５０ＮＬ／ｍｉｎ／ｍ^２の常温空気（１５度）を通気した時のケーキ水分の状況をそれぞれ調査した。通気時間とケーキ水分の低減状況を表１に示す。その結果は、ろ過板だけを加熱するだけでなく常温空気を通気すれば、ケーキ水分は通気開始４０分後には、５〜１０％の水分を多く排出できることを示している。これは、ケーキ外周の加熱板のろ過床に空気を対流させることにより、蒸気として分離された湿潤空気をろ過室から排出し、飽和状態が解消されることにより、さらに水分が蒸発してケーキの含水率が低減したものと考えられる。
【００１９】
【表２】

【００２０】
実験例２
次に、別の観点から通気量とケーキ水分の低減率の実験を行った。４％の浄水スラッジを０．７ＭＰａの圧力でフイルタープレスに圧入ろ過を行い、２０分後に圧入を停止した。その時のろ過室のケーキ水分は９０％であった。このろ過室のケーキに、空気の通気量を５０、１５０、２５０ＮＬ／ｍｉｎ／ｍ^２に設定し、通気時間を１０分から５０分間の５段階に分けて、ろ過室に空気を吹き込み、ケーキ水分を測定した。通気量とケーキ水分の低減状況を表２に示す。その結果は、通気量は短時間の場合、通気量が多いほど水分低下効果が見られた。通気時間が実用的な長時間の５０分となると、１５０ＮＬ／ｍｉｎ／ｍ^２当りで低減率が鈍る傾向が見られ、低減ケーキ水分が５５％となる。従って、含水率９０％のろ過室のケーキに、１５０ＮＬ／ｍｉｎ／ｍ^２の空気を１０分間吹き込めば、低減ケーキ水分が８％程度しかなく、ケーキの含水率は８２％程度であるが、１５０ＮＬ／ｍｉｎ／ｍ^２の空気を５０分間吹き込めば、乾燥するケーキ含水率は４８．６％に低減できることを示している。
【００２１】
【発明の効果】
この発明に係る加温式フイルタープレスは上記のように構成してあり、ろ布を介在せずに金属性の加熱プレートを直接ケーキに接触させ、同時に、ろ過室に常温空気を対流させて、飽和状態の湿潤空気をろ過室から排出し、熱効率とケーキの剥離性を向上させることができる。即ち、従来のろ布を有する加温式フイルタープレスは、剥離性と熱伝導効率が悪く、早期にろ布の能力低下と劣化が生じていた。また、脱水ケーキを加熱しながらろ過室を吸引する装置にあっては、負圧により輻射効果が減少する恐れがあったものであるが、この発明にあっては、加熱プレートとろ板に金属ろ材を張設して、ろ過室のケーキに直接接触させると共に、加熱プレートに、ろ過室に連通する常温空気の給気孔を設けたので、加熱プレートが直接濃縮汚泥やケーキに接触して粘性と比抵抗を低下させ、空気の対流により、ろ過床に発生した湿潤空気を置換させてケーキを乾燥させることができる。そして、加熱プレートの両面を利用するので熱伝導が良く、ろ布を介して加温するより乾燥が速く短時間処理が可能となる。また、金属ろ材は加温による劣化がなく、洗浄しなくてもろ過特性の劣化がない。
【００２２】
加熱プレートは、ろ過床の内部に複数の加熱パイプを配設したもので、全面を加熱して加熱プレートの両面を利用するので熱伝導が良い。そして、ろ板の代わりに、芯板に平板状のダイアフラムを張設したダイアフラムろ板として、直接ケーキに接触させてもよく、ダイアフラムろ板は圧搾水を使うため熱による劣化がなく、ろ過室のケーキの高圧搾が可能となる。また、ろ液溝を有するろ過床を形成したダイアフラムにろ布を吊設してもよく、圧搾によりケーキが塑性変形してろ布から剥離されやすくなる。加熱プレート側のケーキの加熱面は粉状化して容易にケーキ剥離ができる。ろ布もダイアフラムろ板の圧搾水で冷却することができる。
【図面の簡単な説明】
【図１】この発明に係る加温式フイルタープレスのろ過室を形成する加熱プレートとろ板の縦断面図である。
【図２】同じく、ウエッジワイヤーを張設した加熱プレートまたはろ板の平面図である。
【図３】同じく、加熱パイプを配設した加熱プレートの平面図である。
【図４】同じく、ろ板の代わりにダイアフラムろ板を用いた他の実施例の縦断面図である。
【図５】同じく、ダイアフラムろ板の前面にろ布を吊設した他の実施例の縦断面図である。
【符号の説明】
１５加熱プレート
１ａ、３ａ、１２ａろ過床
１ｅ給気孔
２、４ウエッジワイヤー
３ろ板
５ろ過室
６加熱パイプ
７、１０ダイアフラムろ板
８、芯板
９、１２ダイアフラム
９ａ表面
１３ろ布[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a filter press suitable for the treatment of water sewage sludge, sewage sludge, industrial wastewater sludge, and the like, and in particular, the concentrated sludge and cake in the filter chamber of the filter press are heated to improve dehydration, and the water content of the dehydrated cake is improved. It is related with the improvement of the heating type filter press which reduces a rate.
[0002]
[Prior art]
Conventionally, filter presses that can be subjected to filtration pressure are more advantageous for cakes that are incompressible, and are often used as solid-liquid separators. In addition, a filter press using a diaphragm filter plate is squeezable and can be used even for cakes with poor filterability, but the internal retained moisture inside the cake cannot be completely removed by a dehydrator alone. In order to efficiently remove the water, an apparatus for indirectly heating the cake by increasing the temperature inside the filter press has been proposed. For example, Patent Document 1 discloses an apparatus in which a filter cloth is suspended on a heating filter plate and a diaphragm filter plate, and a negative pressure means is provided in the filtration chamber to reduce the moisture content of the dehydrated cake by heating and suctioning the cake. Known as described.
[0003]
[Patent Document 1]
JP 2000-334221 A (paragraph numbers 0031 to 0034, FIG. 3)
[0004]
[Problems to be solved by the invention]
The conventional filter press that heats the dehydrated cake during the dehydration process can improve the processing capacity and reduce the moisture content, but a filter cloth is interposed between the cake and the heating plate, The efficiency of heat conduction from the plate to the cake deteriorated, and it took time to dry. Further, the resinous filter cloth is vulnerable to heat and is pressurized with a diaphragm filter plate, so that the capacity is deteriorated and deteriorated at an early stage. Since both sides of the cake are in contact with the filter cloth, there is a disadvantage that the peelability of the cake is poor. In addition, in a device that reduces the moisture in the cake by heating the dehydrated cake while reducing the pressure in the filtration chamber, the boiling point is lowered by increasing the degree of vacuum, and the moisture in the cake is easily evaporated. However, the effect of radiating heat to the core cake is reduced, and the expected results cannot be obtained. There is a disadvantage that the hermetic seal of the filtration chamber is not perfect and the negative pressure equipment becomes large. The present invention provides a heated filter press in which a metallic heating plate is directly brought into contact with a cake, and at the same time, air is convected in a filtration chamber to discharge moist air, thereby improving thermal efficiency and cake peelability. With the goal.
[0005]
[Means for Solving the Problems]
The gist of the present invention is a filter press in which a heating plate and a filter plate in which a filter bed is formed in a concave shape are alternately arranged to form a filtration chamber, and the heating plate and the filter plate are opened to discharge the dried cake in the filtration chamber. The filter plate of the heating plate and the filter plate formed in a flat plate is stretched with a metal filter medium to be in direct contact with the cake of the filtration chamber, and the heating plate is provided with air supply holes communicating with the filtration chamber. The heating plate is in direct contact with the concentrated sludge or cake to reduce viscosity and specific resistance and improve filterability. The cake can be dried by replacing the moist air generated in the filter bed by air convection. And drying of a cake is quicker than heating through a filter cloth, and a short time process is attained. Further, the metal filter medium does not deteriorate the filter medium due to heating, and the filtration characteristics do not deteriorate even if the filter medium is not washed.
[0006]
The heating means for the cake in the filtration chamber is one in which a plurality of heating pipes are arranged inside the filtration bed of the heating plate, and heat conduction is good because the entire surface is heated to use both sides of the heating plate. Instead of a filter plate with a metal filter medium stretched, a diaphragm filter plate with a diaphragm stretched over a core plate may be used, and the surface of the diaphragm may be formed into a flat plate shape and contacted directly with the cake. Since water is used, there is no deterioration due to heat, and high-pressure squeezing of the cake in the filtration chamber becomes possible. In addition, a filtration bed having a filtrate groove may be formed on the diaphragm stretched on the core plate, and a filter cloth may be suspended on the filtration bed, and the filtrate is discharged from both sides of the cake in the filtration chamber. By pressing, the cake is plastically deformed and easily peeled off from the filter cloth. The heating surface of the cake on the heating plate side is powdered and can be easily peeled off. The filter cloth suspended from the filtration surface of the diaphragm filter plate is not deteriorated by being cooled by the compressed water of the diaphragm filter plate.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The apparatus according to the present invention is configured as described above. When sludge is pressed into a filtration chamber formed by a heating plate and a filter plate, the sludge is filled into the filtration chamber while being concentrated. When the sludge is heated by supplying steam or hot air to the heating plate while injecting the sludge, the heating plate with the wedge wire stretched directly contacts the cake to dry, and the viscosity and specific resistance of the concentrated sludge Decreases, the dewaterability is improved, and the peelability is improved. And the air supplied to the filtration chamber causes convection in the filter bed of the heating plate with the metal filter medium stretched, replaces the wet air generated in the filter bed, dries the cake, and on the filter surface of the metal filter medium and filter plate Drain remaining water droplets. In the cake dried in the filtration chamber, the cake surface on the heating surface is pulverized and easily peeled off from the heating plate, so that a cake with a reduced dehydration time and a low water content can be obtained.
[0008]
If the filter plate provided on the heating plate is a diaphragm filter plate, the cake is pressed by the diaphragm to further reduce the moisture content of the cake, and the pressed cake surface is plastically deformed and easily peeled off from the diaphragm. Moreover, you may hang a filter cloth on the filtration surface of a diaphragm filter board, and a cake peels from a filter cloth by pressing. Diaphragm filter plates and filter cloths do not deteriorate due to heat because they use compressed water. When the filter plate and the heating plate are opened, the heating surface of the cake on the heating plate side is pulverized, and the cake is easily peeled off from the metal filter medium, and the cake is discharged out of the filtration chamber by its own weight. A cake with a reduced pressing time and a low moisture content can be obtained.
[0009]
【Example】
The filter press according to the present invention will be described in detail with reference to the drawings. First, FIG. 1 is a longitudinal sectional view of a heating plate and a filter plate in which a filtration chamber is formed, and a filtration bed 1a having a filtrate discharge groove on the heating plate 1 is provided. The wedge wire 2 is stretched as a metal filter medium on the filter bed 1a. The filtration surface of the wedge wire 2 stretched on the heating plate 1 and the thickness of the peripheral seal portion 1b are formed in a flat plate shape. The filter plate 3 provided on the heating plate 1 is provided with a filter bed 3a having a filtrate discharge groove formed in a concave shape on the inside thereof, and a frame-shaped seal portion 3b on the peripheral surface. A wedge wire 4 is also stretched on the filter bed 3 b of the filter plate 3. Since the filtration plates 1a and 3a for discharging the filtrate are provided on the heating plate 1 and the filter plate 3, the separated filtrate is discharged quickly and the time for solid-liquid separation of sludge is shortened.
[0010]
As shown in FIG. 1, the

wedge wires

2 and 4 stretched on the heating plate 1 and the filter plate 3, respectively, have their expanded wedge-shaped tips abutted against the filtration beds 1a and 3a to heat the filtrate. It is easy to discharge to the filtration beds 1a and 3a of the plate 1 and the filter plate 3. FIG. 2 is a plan view of a heating plate or a filter plate.

Wedge wires

2 and 4 stretched between the heating plate 1 and the filter plate 3 have slits 2a and 4a as filtration surfaces, and the slits 2a and 4a are moved up and down. It is arranged in the direction. Many heating plates 1 and filter plates 3 are arranged in parallel, and when the heating plate 1 and the filter plate 3 are closed, the front and rear heating plates 1 and the filter plate 3 form a filtration chamber 5. In addition, the

wedge wires

2 and 4 stretched between the heating plate 1 and the filter plate 3 may be punched metal, and the metal filter medium has good heat conduction, can be dried quickly and can be processed in a short time. Further, the metal filter medium does not deteriorate the filter medium due to heating, and there is no deterioration of the filtration characteristics even if it is not washed.
[0011]
As shown in FIG. 1, undiluted solution supply paths 1c and 3c are provided in the upper seal portions 1b and 3b of the heating plate 1 and the filter plate 3, and when the parallel heating plate 1 and filter plate 3 are closed, the heating plate 1 and the filter plate 3 are filtered. The stock solution supply passages 1c and 3c communicate with the upper seal portions 1b and 3b of the plate 3. The stock solution supply paths 1 c and 3 c are communicated with the front surface of the wedge wire 4 via the liquid supply hole 3 d of the filter plate 3, and press the stock solution into the filtration chamber 5 between the heating plate 1 and the filter plate 3. In the embodiment of the present invention, the stock solution is injected at a pressure of 0.7 to 1.5 MPa. Moreover, the filtrate discharge hole 3e connected to the filtration bed 3a is provided in the seal part 3b at the lower part of the filter plate 3, and the filtrate is discharged outside the apparatus. A filtrate discharge hole 1d communicating with the filtration bed 1a on the back surface of the wedge wire 2 is also provided in the lower seal portion 1b of the heating plate 1, and the filtrate subjected to solid-liquid separation with the wedge wire 2 is filtered into the filtrate discharge hole 1d. Also discharged from.
[0012]
FIG. 3 is a plan view of the heating plate, in which a plurality of heating pipes 6 are arranged inside the heating plate 1, steam or hot air is supplied from a supply port 6 a provided in the heating plate 1, It discharges from the discharge port 6b of the heating plate 1. In the embodiment of the present invention, the heating plate 1 is heated to 75 to 85 ° C. and transmitted from the filtration bed 1a to the wedge wire 2 by heat conduction to directly heat the dehydrated cake. The viscosity and specific resistance of the concentrated sludge and cake are lowered and the dewaterability is improved. The cake in the filtration chamber 5 is easily peeled off from the wedge wire 2 stretched on the heating plate 1 by pulverizing the cake surface of the heating surface. Since both surfaces of the heating plate 1 are used, the heat efficiency is high, and the wedge wire 2 heated by heat conduction from the heating plate 1 directly contacts the cake, and drying is performed quickly.
[0013]
As shown in FIG. 3, an air supply hole 1e communicating with the filtration bed 1a is provided in the upper seal portion 1b of the heating plate 1, and the filtration chamber 5 formed by the heating plate 1 and the filter plate 3 is used in the embodiment of the present invention. Then, normal temperature air (10 to 20 ° C.) with an air amount of 150 NL / min / m ² is supplied for 50 minutes. The air supplied to the filtration chamber 5 is convected between the back surface of the wedge wire 2 and the filtration bed 1 a and discharged from the filtrate discharge hole 1 d of the heating plate 1. Moist air evaporated from the cake is replaced with saturated air, and dry air is supplied to easily evaporate the moisture in the cake. Water droplets remaining on the wedge wire 2 and the filtration bed 1a of the heating plate 1 are also blown away, and a cake with a reduced dehydration time and a low water content can be obtained. The air supplied to the filtration chamber 5 varies depending on the season, and the supply time of the room temperature air may be appropriately set in consideration of the properties of the cake.
[0014]
If the heating cake 1 and the filter plate 3 are opened in the dry cake generated in the filtration chamber 5, the heating surface of the cake on the heating plate 1 side is powdered and easily peeled from the wedge wire 2. The cake is peeled off from the wedge wire 4 stretched on the filter plate 3 by its own weight, and falls along the slit 4a. In addition, even if it makes the

wedge wires

2 and 4 punching metal, it contacts the cake of the filtration chamber 5 directly, and its heat transfer efficiency is good. Moreover, the air supply holes 1 e for room temperature air provided in the heating plate 1 may be arranged in the filter plate 3. If necessary, a known scraper that can be moved up and down is disposed above the heat plate 1 and may be slid on the

wedge wires

2 and 4 of the heating plate 1 and the filter plate 3.
[0015]
FIG. 4 shows another embodiment using a diaphragm filter plate, in which heating plates 1 and diaphragm filter plates 7 are alternately arranged in parallel, and the diaphragm filter plate 7 has a surface on a core plate 8 formed in a concave shape. A diaphragm 9 having a flat plate shape 9a is stretched. A liquid supply plate 14 is fixed to the front surface of the stock solution supply path 7a of the diaphragm filter plate 7. The stock solution passes from the stock solution supply path 7a of the diaphragm filter plate 7 through the liquid supply hole 14a of the liquid supply plate 14 and the filtration chamber 5a. To be subjected to solid-liquid separation. After completion of the injection of the stock solution, high-pressure water is supplied to the back surface of the diaphragm 9 from the pressure water hole 8b provided in the seal portion 8a of the core plate 8, the cake is squeezed, and separated from the filtrate discharge hole 1d of the heating plate 1. Drain the filtrate. The cake surface to be squeezed is plastically deformed and easily peeled off from the diaphragm 9. The diaphragm 9 stretched on the diaphragm filter plate 7 does not deteriorate due to heat because it uses water for squeezing.
[0016]
FIG. 5 shows another embodiment in which a filter cloth is suspended on the front surface of a diaphragm filter plate. A diaphragm filter plate 10 provided on the heating plate 1 has a filtrate groove on a core plate 11 formed in a concave shape. A diaphragm 12 is stretched. Filter cloths 13, 13 are suspended before and after the diaphragm filter plate 10, and a liquid supply plate 14 is fixed to the upper part of the filter cloth 13. The liquid supply plate 14 is opposed to the raw solution supply paths 1c and 10a of the raw solution provided on the heating plate 1 and the diaphragm filter plate 10. The stock solution passes from the stock solution supply passages 1c and 10a through the feed hole 14a of the feed plate 14 and press-fits into the filtration chamber 5b. A pressure water hole 11 b that communicates with the back surface of the diaphragm 12 and a filtrate discharge hole 11 c that communicates with the filtrate groove of the diaphragm filter plate 10 on the back surface of the filter cloth 13 are provided in the seal portion 11 a of the core plate 11. The contact surface between the cake and the filter cloth 13 is only one surface on the diaphragm filter plate 10 side to be squeezed, and the filter cloth 13 is not cooled and deteriorated by the compressed water of the diaphragm filter plate 10. If the dry cake produced | generated in the filtration chamber 5b opens the heating plate 1 and the diaphragm filter board 10, the cake which is squeezed by the diaphragm 12 and is plastically deformed will peel from the diaphragm 12 and the filter cloth 13 by its own weight. .
[0017]
[Table 1]

[0018]
Experimental example 1
Experiments on the aeration time and cake moisture reduction rate were conducted with a filter press equipped with a heating plate. First, 4% of purified water sludge was pressed into a filter press at a pressure of 0.7 MPa, and after 20 minutes, the press of purified water sludge was stopped. The moisture content of the dehydrated cake at that time was 90%. Next, the cake in the filtration chamber is squeezed with a diaphragm at 1.5 MPa, and while maintaining this state, the heating plate is heated at 75 ° C. and 85 ° C., and the filter plate is heated at 75 ° C. and 85 ° C. Then, the state of the cake moisture when the air amount was aerated with room temperature air (15 degrees) with 150 NL / min / m ² was investigated. Table 1 shows the aeration time and cake moisture reduction. The result shows that if not only the filter plate is heated but also room temperature air is ventilated, the cake moisture can be discharged by a large amount of 5 to 10% after 40 minutes from the start of aeration. This is because air is convected to the filtration bed of the heating plate on the outer periphery of the cake, so that the moist air separated as vapor is discharged from the filtration chamber and the saturated state is eliminated. It is thought that the moisture content was reduced.
[0019]
[Table 2]

[0020]
Experimental example 2
Next, an experiment was conducted on the air flow rate and cake moisture reduction rate from another viewpoint. 4% purified water sludge was subjected to pressure filtration into a filter press at a pressure of 0.7 MPa, and the pressure injection was stopped after 20 minutes. The cake moisture in the filtration chamber at that time was 90%. Set the air flow rate to 50, 150, 250 NL / min / m ² for the cake in this filtration chamber, divide the ventilation time into 5 stages from 10 minutes to 50 minutes, blow air into the filtration chamber, It was measured. Table 2 shows the amount of aeration and cake moisture reduction. As a result, when the aeration amount was short, the moisture reduction effect was seen as the aeration amount increased. When the ventilation time is 50 minutes, which is a practical long time, the reduction rate tends to be dulled per 150 NL / min / m ² , and the reduced cake moisture becomes 55%. Therefore, if air of 150 NL / min / m ² is blown into a cake in a filtration chamber having a moisture content of 90% for 10 minutes, the reduced cake moisture is only about 8% and the moisture content of the cake is about 82%. It shows that the moisture content of the cake to be dried can be reduced to 48.6% by blowing air at / min / m ² for 50 minutes.
[0021]
【The invention's effect】
The heating type filter press according to the present invention is configured as described above, and a metal heating plate is directly brought into contact with the cake without interposing a filter cloth, and at the same time, normal temperature air is convected in the filtration chamber, Saturated moist air can be discharged from the filtration chamber to improve thermal efficiency and cake peelability. That is, the heating type filter press having a conventional filter cloth has poor peelability and heat conduction efficiency, and the capacity of the filter cloth is deteriorated and deteriorated at an early stage. In addition, in a device that sucks the filtration chamber while heating the dehydrated cake, there is a risk that the radiation effect may be reduced by negative pressure. In the present invention, a metal filter medium is used for the heating plate and the filter plate. Since the heating plate is provided with air supply holes for room temperature air that communicates with the filtration chamber, the heating plate directly contacts the concentrated sludge and cake. The cake can be dried by reducing resistance and replacing the humid air generated in the filter bed by air convection. And since both surfaces of a heating plate are utilized, heat conduction is good, and drying is quicker than heating through a filter cloth, and it becomes possible to process for a short time. Further, the metal filter medium is not deteriorated by heating, and the filtration characteristics are not deteriorated even if it is not washed.
[0022]
The heating plate has a plurality of heating pipes arranged inside the filtration bed, and heat conduction is good because both surfaces of the heating plate are used by heating the entire surface. And instead of the filter plate, as a diaphragm filter plate in which a flat diaphragm is stretched on the core plate, it may be brought into direct contact with the cake, and since the diaphragm filter plate uses compressed water, there is no deterioration due to heat, and the filtration chamber Of the cake can be pressed. Moreover, you may hang a filter cloth on the diaphragm which formed the filtration bed which has a filtrate groove | channel, and it will become easy to peel from a filter cloth by a plastic deformation by pressing. The heating surface of the cake on the heating plate side is powdered and can be easily peeled off. The filter cloth can also be cooled with the compressed water of the diaphragm filter plate.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a heating plate and a filter plate forming a filtration chamber of a heated filter press according to the present invention.
FIG. 2 is also a plan view of a heating plate or a filter plate in which a wedge wire is stretched.
FIG. 3 is also a plan view of a heating plate provided with a heating pipe.
FIG. 4 is also a longitudinal sectional view of another embodiment in which a diaphragm filter plate is used instead of the filter plate.
FIG. 5 is also a longitudinal sectional view of another embodiment in which a filter cloth is suspended from the front surface of a diaphragm filter plate.
[Explanation of symbols]
15 Heating plates 1a, 3a, 12a Filtration bed 1e

Air supply holes

2, 4 Wedge wire 3 Filter plate 5 Filtration chamber 6 Heating pipe 7, 10 Diaphragm filter plate 8, Core plate 9, 12 Diaphragm 9a Surface 13 Filter cloth

Claims

加熱プレート（１）とろ過床（３ａ）を凹面状に形成したろ板（３）を交互に並列してろ過室（５）を形成し、加熱プレート（１）とろ板（３）を開板してろ過室（５）の乾燥ケーキを排出させるフイルタープレスにおいて、平板状に形成した加熱プレート（１）とろ板（３）のろ過床（３ａ）に金属ろ材（２、４）を張設して、ろ過室（５）のケーキに直接接触させると共に、加熱プレート（１）に、ろ過室（５）に連通する空気の給気孔（１ｅ）を設けたことを特徴とする加温式フイルタープレス。Filtration chambers (5) are formed by alternately arranging heating plates (1) and filter plates (3) formed in a concave shape on the filter bed (3a), and heating plates (1) and filter plates (3) are opened. In the filter press for discharging the dry cake in the filtration chamber (5), the metal filter media (2, 4) are stretched on the filter bed (3a) of the heating plate (1) and the filter plate (3) formed in a flat plate shape. A heating type filter press characterized in that the heating plate (1) is provided with air supply holes (1e) communicating with the filtration chamber (5) in direct contact with the cake of the filtration chamber (5).

上記加熱プレート（１）のろ過床（１ａ）の内部に複数の加熱パイプ（６）を配設したことを特徴とする請求項１に記載の加温式フイルタープレス。The heating type filter press according to claim 1, wherein a plurality of heating pipes (6) are arranged inside the filtration bed (1a) of the heating plate (1).

上記金属ろ材（４）を張設したろ板（３）の代わりに、芯板（８）にダイアフラム（９）を張設したダイアフラムろ板（７）とし、ダイアフラム（９）の表面（９ａ）を平板状に形成して、直接ケーキに接触させることを特徴とする請求項１または２に記載の加温式フイルタープレス。Instead of the filter plate (3) stretched with the metal filter medium (4), a diaphragm filter plate (7) with a diaphragm (9) stretched on the core plate (8) is used, and the surface (9a) of the diaphragm (9) The heating type filter press according to claim 1 or 2, wherein is formed into a flat plate shape and directly brought into contact with the cake.

上記芯板（８）に張設するダイアフラム（９）に、ろ液溝を有するろ過床（１２ａ）を形成し、そのろ過床（１２ａ）にろ布（１３）を吊設したことを特徴とする請求項３項に記載の加温式フイルタープレス。The diaphragm (9) stretched on the core plate (8) is formed with a filtration bed (12a) having a filtrate groove, and a filter cloth (13) is suspended from the filtration bed (12a). The heating type filter press according to claim 3.