JP3987815B2 - Surface modification method of structure - Google Patents

Description

（１）主ノズルから低圧室に高圧水を噴射させ、次いで補助ノズルへ流入させると低圧室内が低圧になる。低圧室に空気導入部が形成されているので、空気導入部から低圧室内に所定量の空気をスムーズに導入することができる。さらに空気導入部から導入された空気の空気混合比Ｙがノズル比Ｘと（数２）で示す関係にあるので、空気導入部から導入された空気によって液柱が微細に分裂されて液滴化が進行し液滴のジェット流のエネルギーを増大させ、さらに空気と液滴の混相流の体積が増加することにより補助ノズル内の圧力が高まり液滴の速度を高め液滴の運動エネルギーが低下するのを防止することができる。
（２）ノズル比と高圧水の流量を決めれば空気導入部から低圧室に導入する空気の最適の流量を容易にかつ迅速に決定することができるので、ノズルの設計を容易にするとともに高いエネルギー効率を有するノズルを確実に製造することができ生産性に優れるとともに製品得率を高めることができる。
【００２３】
ここで、（数２）は、ノズル比Ｘ（ｂ／ａ）と、空気導入部から導入され高圧水に連行された空気の流量（ｃ）と高圧水の流量（ｄ）との比である空気混合比Ｙ（ｄ／ｃ）との間の関係を実験から求め、噴射した液滴によって構造体の表面の改質を行うことができる最適範囲について規定した式である。なお、ｆは高圧水の圧力や補助ノズルの長さ等によって決まる定数である。
空気混合比Ｙがノズル比Ｘの１．７乗に比例するのは以下の理由であると推察している。高圧水に連行される空気は、主ノズルから噴射された液柱の外周と補助ノズルの内周面との隙間から補助ノズル内に侵入する。この隙間の断面積はノズル比（ｂ／ａ）のほぼ２乗に比例し、高圧水の流量（ｄ）が一定の場合、空気の流量（ｃ）は隙間の断面積、即ちノズル比（ｂ／ａ）のほぼ２乗に比例する。しかし、液柱は主ノズルから噴射されると外側に拡がり液柱の外周と補助ノズルの内周面との隙間は小さくなる。さらに連行される空気と補助ノズルの内周面との摩擦等によって損失が生じるので、空気混合比Ｙはノズル比Ｘの２乗より若干小さな１．７乗に比例する。
【００２４】
（数２）において、ｆが０．２より小さくなるにつれ高圧水に連行された空気の流量が少なく液柱が充分に液滴化せず液滴のジェット流の運動エネルギーを大きくすることができず構造体の表面改質効率が低下する傾向がみられ、ｆが０．８より大きくなるにつれ高圧水に連行される空気の流量が多くなり液滴のジェット流が乱れ構造体の表面改質効率が低下する傾向がみられたり、高圧水に連行された空気の流量の増加とともに高圧水の流量も増加し液柱の液滴化効率が低下し構造体の表面の錆や異物等を除去する等の表面改質効率が低下する傾向がみられるため、いずれも好ましくない。
【００２５】
本発明の請求項３に記載の発明は、請求項１又は２に記載の構造体の表面改質方法であって、前記高圧水が、水を電気分解して得られた還元水である構成を有している。
この構成により、請求項１又は２で得られる作用に加え、以下のような作用が得られる。
（１）水を電気分解して得られた還元水を用いることによって、構造体の表面の脱脂ができ、構造体が鋼板や棒状鋼等の金属製で形成されると構造体の表面が還元されて防錆効果が得られるとともに構造体の表面が不動態化して耐酸化性を向上させ赤錆の発生を防止することができ防食性に優れる。また、構造体の乾燥時にマクロセル、ミクロセル化による腐食電池の形成を防止し発錆を防止することができる。
（２）水を電気分解して得られた還元水は、空気中に放置しておくと酸化され酸化還元電位が低下して還元力が低下するとともに中性化されるため、排水処理設備等を必要としない。
【００２６】
ここで、水を電気分解して得られた還元水としては、ｐＨが８〜１４好ましくは９〜１２にされたものが好適に用いられる。ｐＨが９より小さくなるにつれ構造体の表面が不動態化され難く赤錆が発生し易くなる傾向がみられ、ｐＨが１２より大きくなるにつれ還元水の生成に多大なエネルギーを要し省エネルギー性が低下する傾向がみられる。特に、ｐＨが８より小さくなるか１４より大きくなるとこれらの傾向が著しいため、いずれも好ましくない。
【００２７】
還元水の酸化還元電位は、−１００〜−９００ｍＶ好ましくは−２００〜−６００ｍＶが好適に用いられる。酸化還元電位が−２００〜−６００ｍＶのときは高い還元力が得られ、さらに構造体が不動態化され易く赤錆が発生し難く好ましい。酸化還元電位が−２００ｍＶより小さくなるにつれ、ｐＨによっては構造体が不動態化され難く赤錆が発生し易くなる傾向がみられ、−６００ｍＶより大きくなるにつれ、還元水の生成に多大なエネルギーを要し省エネルギー性が低下する傾向がみられ、さらに還元力が強いため空気中の酸素によって急速に酸化され酸化還元電位が急激に低下する傾向がみられる。特に、酸化還元電位が−１００ｍＶより小さくなるか−９００ｍＶより大きくなるとこれらの傾向が著しいため、いずれも好ましくない。
【００２８】
なお、還元水を生成する際、水に塩化ナトリウム，塩化カルシウム，ヒドラジン等の電解質を添加しないのが好ましい。ヒドラジン等の電解質は有害であり、また、塩化ナトリウム等の電解質を添加すると還元水中の残留塩素濃度等が高まり、構造体の表面に残留した残留塩素等によって構造体が腐食され易く錆が発生し易くなり、さらに洗浄後に表面に塗膜を形成する際の密着性等にも悪影響を及ぼすからである。
【００２９】
本発明の請求項４に記載の発明は、請求項３に記載の構造体の表面改質方法であって、前記還元水が、電解質が添加されていない水を電気分解して得られた構成を有している。
この構成により、請求項３で得られる作用に加え、以下のような作用が得られる。
（１）ヒドラジン等の電解質は有害であり、また、塩化ナトリウム等の電解質を添加すると還元水中の残留塩素濃度等が高まり、構造体の表面に残留した残留塩素等によって構造体が腐食され易く錆の発生を抑制でき、さらに洗浄後に表面に塗膜を形成する際の密着性等に悪影響を及ぼすのを防止できる。
【００３０】
【発明の実施の形態】
以下、本発明の一実施の形態を、図面を参照しながら説明する。
（実施の形態１）
図１は実施の形態１における液滴噴射ノズルの要部断面斜視図であり、図２は実施の形態１における液滴噴射ノズルの要部断面図である。
図中、１は実施の形態１における液滴噴射ノズル、２は筒状に形成された本体、３は本体２の内部に後述する主ノズル４や補助ノズル７の内径より大きな内径の筒状に形成された低圧室、４は低圧室３の一端側に配設された内径ａの主ノズル、５は本体２の一端側に螺着され端面で主ノズル４を押圧して本体２内に固定する高圧水管、６は高圧水管５の軸中心に形成された高圧水流路、７は主ノズル４の下流側の低圧室３の他端側に主ノズル４と所定間隔をあけて同心状に配設された内径ｂの補助ノズル、８は本体２の他端側に螺着され補助ノズル７を固定する補助ノズル固定部、９は補助ノズル７の出口と距離ｈだけ、また主ノズル４の出口と距離Ｌだけ離間して配設された鋼，ステンレス鋼等で形成された鋼板等、自動車や電車等の車両や船舶等、橋梁や鉄塔等、加熱器，ボイラ等、鉄筋コンクリート製や石材等で形成された構造体である。
実施の形態１においては、主ノズル４の内径ａと、補助ノズル７の内径ｂとの比であるノズル比（ｂ／ａ）が、２〜２５好ましくは３〜１５で形成されている。また、主ノズル４の内径ａと主ノズル４の出口から補助ノズル７の出口までの距離（Ｓ）との比（Ｓ／ａ）が５０〜４００になるように形成されている。また、液滴噴射ノズル１は、主ノズル４の内径ａと補助ノズル７の出口から構造体１０の表面までの距離（ｈ）との比（ｈ／ａ）が１０〜５００好ましくは２０〜４００になるような位置に配設されている。また、主ノズル４の内径ａと主ノズル４の出口から構造体９の表面までの距離（Ｌ）との比（Ｌ／ａ）が６０〜８００好ましくは７０〜８００になるような位置に配設されている。
【００３１】
以上のように構成された実施の形態１における液滴噴射ノズルを用いた構造体の表面改質方法ついて、以下その動作を説明する。
高圧水流路３に水を圧送して圧力２５〜１５０ＭＰａ好ましくは３０〜１００ＭＰａに加圧した高圧水を液柱として内径ａの主ノズル４から内径ｂの補助ノズル５に向かって噴射すると、低圧室３内が低圧になる。ノズル比（ｂ／ａ）が２〜２５好ましくは３〜１５に形成されているので、主ノズル４から噴射された高圧水の液柱表面と補助ノズル７の内周面とに適度の間隙が形成され、この間隙に補助ノズル７の出口から低圧室３に向かって空気が吸引される。主ノズル４から補助ノズル７に流入された高圧水は、低圧室３に吸引された空気の気流との間に生じる剪断力によって微粒化され効率良く液滴化される。また、低圧室３に吸引された空気によって補助ノズル７内に空気と液滴の混相流が形成され混相流の体積が増加し、補助ノズル７内の圧力が高まりエネルギーが増加し液滴が加速される。さらに、低圧室３に吸引された空気は、主ノズル４から噴射された高圧水に随伴されて気流を形成し、空気とジェット流間の相対速度を小さくするので、低圧室３内や補助ノズル７内でジェット流が広がるのを防止し液滴のエネルギー密度を高める。
液滴は、高い運動エネルギーを保持したまま補助ノズル７から構造体９に向けてジェット流として噴射される。補助ノズル７から噴射された液滴は、構造体９の表面の錆や異物等を除去する洗浄、構造体９の表面の劣化塗料やコンクリート劣化層、砥石表面の磨耗層を除去するはつり等の表面改質を行う。
【００３２】
以上のように、実施の形態１における液滴噴射ノズルは構成されているので、以下のような作用が得られる。
（１）ノズル比（ｂ／ａ）が２〜２５好ましくは３〜１５に設定されているので、補助ノズルに流入された高圧水は、低圧室に吸引された空気の気流との間に生じる剪断力によって微粒化され効率良く液滴化されるので、高圧水の圧力エネルギーが液滴の運動エネルギーに効率良く変換されエネルギー効率に優れる。
（２）低圧になった低圧室に吸引された空気は、噴射された高圧水に随伴されて気流を形成するので、高圧水が形成するジェット流の界面で空気とジェット流間の相対速度を小さくしてジェット流が広がるのを防止して収束性を高め単位断面積あたりの液滴のエネルギーを高めることができる。
（３）低圧室に空気が吸引されることにより空気と液滴の混相流が形成され、補助ノズル内を流れる液滴を含む混相流の体積が増加する。これにより、補助ノズル内の圧力が高まりエネルギーが増加し液滴が加速されるので、高圧水の圧力が低くても液滴の運動エネルギーを増加させエネルギー効率を高めることができ、従来の高圧水より低い圧力で、極めて高い表面改質効果を得ることができる。
（４）補助ノズル内の液滴の速度は主ノズルの出口から所定の距離で最大となり、それを超えると空気抵抗により減少する傾向がみられるが、比（Ｓ／ａ）が５０〜４００で形成されているので、液滴の運動エネルギーを低下させず補助ノズルから噴射されたジェット流の運動エネルギーによって大きな表面改質効果を得ることができる。
【００３３】
また、実施の形態１における液滴噴射ノズルを用いた構造体の表面改質方法によれば、
（１）高圧水の圧力が２５〜１５０ＭＰａ好ましくは３０〜１００ＭＰａの低圧力にあるので、水を加圧する大型の高圧ポンプを必要としない。
（２）高圧水の圧力が低いので主ノズル等の磨耗が少なく耐久性に優れるとともに部品交換等を頻繁に行う必要がなくメンテナンスも容易で作業性に優れる。
（３）高圧水の圧力が低いので構造体に液滴化された高圧水を噴射したときの反動が少なく、作業者は多大な力を要さずに主ノズルや補助ノズルを保持することができ操作性に優れる。さらに、ロボット等の設備を用いて自動化する際でも、反動が少ないのでノズルの保持具を大型化する必要がなく設備を小型化・軽量化することができる。
（４）主ノズルの内径（ａ）と主ノズルの出口から構造体の表面までの距離（Ｌ）との比（Ｌ／ａ）が６０〜８００好ましくは７０〜８００で形成されているので、主ノズルから噴射された高圧水の圧力エネルギーを液滴の運動エネルギーに効率良く変換して大きな表面改質効果を得ることができる。
（５）主ノズルの内径（ａ）と補助ノズルの出口から構造体の表面までの距離（ｈ）との比（ｈ／ａ）が１０〜５００好ましくは２０〜４００で形成されているので、補助ノズルから噴射されたジェット流の運動エネルギーを低下させず大きな表面改質効果を得ることができる。
【００３４】
実施の形態１で説明した構造体の表面改質方法において、高圧水として水を電気分解して得られた還元水を用いる場合もある。これにより、構造体の表面の脱脂ができ、さらに構造体が金属製で形成されると構造体の表面が還元されて防錆効果が得られるとともに構造体の表面が不動態化して耐酸化性を向上させ赤錆の発生を防止することができ防食性に優れる。また、構造体の乾燥時にマクロセル、ミクロセル化による腐食電池の形成を防止し発錆を防止することができるという作用が得られる。
【００３５】
（実施の形態２）
図３は実施の形態２における液滴噴射ノズルの要部断面図である。なお、実施の形態１で説明したものと同様のものは、同じ符号を付して説明を省略する。
図中、１０は本体２の１乃至複数箇所に貫設され外部と低圧室３とを連通する空気導入部である。なお、実施の形態２における液滴噴射ノズルは、ノズル比Ｘ（ｂ／ａ）と、空気導入部１０から導入され高圧水に連行された空気の流量（ｃ）と高圧水の流量（ｄ）との比である空気混合比Ｙ（ｃ／ｄ）が（数３）の関係になるように構成されている。
【数３】

実施の形態２の液滴噴射ノズルが実施の形態１と異なる点は、低圧室３が本体２に貫設された空気導入部１０を有している点である。
【００３６】
この構成の相違により、実施の形態２における液滴噴射ノズルは、実施の形態１に記載の作用に加え、以下のような作用が得られる。
（１）低圧室に空気導入部が形成されているので、空気導入部から低圧室内に所定量の空気をスムーズに導入することができる。さらに空気導入部から導入された空気の空気混合比Ｙがノズル比Ｘと（数３）で示す関係にあるので、空気導入部から導入された空気によって液柱が微細に分裂されて液滴化が進行し液滴のジェット流のエネルギーを増大させ、さらに空気と液滴の混相流の体積が増加することにより補助ノズル内の圧力が高まり液滴の速度を高め、液滴の運動エネルギーが低下するのを防止することができる。
（２）ノズル比と高圧水の流量を決めれば空気導入部から低圧室に導入する空気の最適の流量を容易にかつ迅速に決定することができるので、ノズルの設計を容易にするとともに高いエネルギー効率を有するノズルを確実に製造することができ生産性に優れるとともに製品得率を高めることができる。
【００３７】
【実施例】
以下、本発明を実施例により具体的に説明する。なお、本発明はこれらの実施例に限定されるものではない。
（実施例１〜１６、比較例１〜２）
実施の形態２で説明した液滴噴射ノズルを用いて構造体の表面改質を行う実験を行った。
以下の実験においては、空気導入部から低圧室内へ導入される空気の流量を測定するため、空気導入部に流量計を接続し、空気は流量計を通って空気導入部から低圧室内へ導入されるようにした。さらに、流量計には開閉弁を配設して、開閉弁を閉止することにより空気導入部から低圧室内へ空気が導入されないようにすることもできるようにした。また、高圧水流路に流量計を接続し高圧水の流量を測定した。構造体としては１辺の長さ４０ｍｍ、厚さ１ｍｍのＳＵＳ３０４ステンレス鋼製薄板を用い、所定圧力に加圧した高圧水のジェット流を主ノズルから構造体（ステンレス鋼製薄板）の５箇所へ各々１分間ずつ噴射した。噴射前後の構造体の重量減少量を測定し、重量減少量の大きなものほど表面改質効果が高いと評価した。
実施例１〜１８の主ノズルの内径（ａ）、補助ノズルの内径（ｂ）、ノズル比（ｂ／ａ）、流量計で測定された空気の流量（ｃ）、高圧水の流量（ｄ）、高圧水の圧力、補助ノズルの出口から構造体の表面までの距離（ｈ）、及び構造体の重量減少量を表１にまとめて示す。なお、補助ノズルの長さ（補助ノズルの入口から出口までの長さ）としては８０ｍｍのものを用いた。また、実施例８乃至１８は、空気導入部に接続された開閉弁を閉止して空気導入部から低圧室内へ空気が導入されないようにしたため、空気導入部からの空気の流量が０である。
図４は実施例１〜１８のノズル比（ｂ／ａ）と重量減少量との関係を示した図である。
【００３８】
【表１】

【００３９】
表１及び図４から、ノズル比（ｂ／ａ）が２〜２５の場合、特に３〜１５の場合に、空気導入部からの空気の流量が０でも顕著な重量減少が得られることが明らかになった（実施例８〜１３）。このことは、補助ノズルに流入された高圧水が補助ノズルから低圧室に吸引された空気の気流との間に生じる剪断力によって微粒化され効率良く液滴化されていることを示していると推察される。また、開閉弁を開弁して空気導入部から空気を導入することにより、重量減少量をさらに大きくできることが確認された（実施例１〜７）。なお、実施例１４〜１８の重量減少量が実施例８〜１３より小さいのは、高圧水の圧力が５０ＭＰａと小さいことと補助ノズルの出口から構造体までの距離ｈが異なることによるものであり、高圧水の圧力や距離ｈが重量減少量に影響を与えることが確認された。
【００４０】
（実施例１９〜３５、比較例１）
実施例１９〜３５、比較例１において、主ノズルの内径（ａ）、補助ノズルの内径（ｂ）、ノズル比（ｂ／ａ）、流量計で測定された空気の流量（ｃ）、高圧水の流量（ｄ）、空気混合比（ｃ／ｄ）、高圧水の圧力、及び構造体の重量減少量を表２にまとめて示す。なお、補助ノズルの出口から構造体の表面までの距離（ｈ）は１５ｍｍ、補助ノズルの長さ（補助ノズルの入口から出口までの長さ）としては８０ｍｍのものを用いた。
図５は実施例１９〜３５、比較例１のノズル比Ｘ（ｂ／ａ）と空気混合比Ｙ（ｃ／ｄ）との関係を示した図である。
【００４１】
【表２】

【００４２】
表２及び図５から、ノズル比Ｘ（ｂ／ａ）と空気混合比Ｙ（ｃ／ｄ）との関係が、（数４）の範囲内にある場合に顕著な重量減少が得られることが確認された。
【数４】

以上のように本実施例によれば、空気導入部から導入された空気によって液柱が微細に分裂されて液滴化が進行し液滴のジェット流のエネルギーを増大させ、さらに空気導入部から低圧室に吸引された空気によって空気と液滴の混相流の体積が増加することにより補助ノズル内の圧力が高まり液滴の速度を高め、液滴の運動エネルギーが低下するのを防止することができると推察された。よって、ノズル比と高圧水の流量を決定することにより（数４）の関係から、空気導入部から低圧室に導入する空気の流量を容易にかつ簡便に決定することができるため、低圧室の大きさ、空気導入部の大きさや数量等を容易に決定することができ設計効率を高めるとともに製品得率を高めることができることが明らかになった。
なお、空気導入部にポンプを接続し空気導入部から空気を圧入して空気の流量を増やし、（数４）のｆが０．８より大きくなるようにした場合には、構造体の重量減少量はほぼ０になった。これは、空気の流量が増えた結果、液滴のジェット流が乱れ構造体の表面改質効率が低下したと推察している。
【００４３】
（実施例３６〜５５、比較例２）
実施例３６〜５５、比較例２において、流量計で測定された空気の流量（ｃ）、高圧水の流量（ｄ）、空気混合比（ｃ／ｄ）、高圧水の圧力、補助ノズルの長さ（補助ノズルの入口から出口までの長さ）、補助ノズルの出口から構造体の表面までの距離（ｈ）、主ノズルの内径（ａ）と補助ノズルの出口から構造体の表面までの距離（ｈ）との比（ｈ／ａ）、及び構造体の重量減少量を表３にまとめて示す。なお、主ノズルの内径（ａ）としては０．４５ｍｍ、補助ノズルの内径（ｂ）としては２．０ｍｍのものを用い、主ノズルの出口から補助ノズルの入口までの距離は１５ｍｍとした。
図６は実施例３６〜５５、比較例２の主ノズルの内径（ａ）と補助ノズルの出口から構造体の表面までの距離（ｈ）との比（ｈ／ａ）と重量減少量との関係を示した図である。
【００４４】
【表３】

【００４５】
表３及び図６から、主ノズルの内径（ａ）と補助ノズルの出口から構造体の表面までの距離（ｈ）との比（ｈ／ａ）が４００より大きくなるにつれ重量減少量が著しく低下する傾向を示すものがみられ、２０より小さくなるにつれ重量減少量が低下する傾向を示すものがみられることが確認された。
以上のように本実施例によれば、主ノズルの内径（ａ）と補助ノズルの出口から構造体の表面までの距離（ｈ）との比（ｈ／ａ）が１０〜５００好ましくは２０〜４００の場合に、補助ノズルから噴射されたジェット流の運動エネルギーを低下させず大きな表面改質効果を得ることができることが明らかになった。
【００４６】
（実施例５６〜７５、比較例３〜４）
実施例５６〜７５、比較例３〜４において、補助ノズルの長さ（補助ノズルの入口から出口までの長さ）、補助ノズルの出口から構造体の表面までの距離（ｈ）、主ノズルの出口から構造体の表面までの距離（Ｌ）、主ノズルの内径（ａ）と主ノズルの出口から構造体の表面までの距離（Ｌ）との比（Ｌ／ａ）、高圧水の圧力、及び構造体の重量減少量を表４にまとめて示す。なお、主ノズルの内径（ａ）としては０．４５ｍｍ、補助ノズルの内径（ｂ）としては２．０ｍｍのものを用い、主ノズルの出口から補助ノズルの入口までの距離は１５ｍｍとした。また、空気導入部に接続された開閉弁は全開した。
図７は実施例５６〜７５、比較例３〜４の主ノズルの内径（ａ）と主ノズルの出口から構造体の表面までの距離（Ｌ）との比（Ｌ／ａ）と重量減少量との関係を示した図である。
【００４７】
【表４】

【００４８】
表４及び図７から、主ノズルの内径（ａ）と主ノズルの出口から構造体の表面までの距離（Ｌ）との比（Ｌ／ａ）が８００より大きくなるにつれ重量減少量が低下し、７０より小さくなるにつれ重量減少量が小さくなる傾向を示し、６０より小さくなると著しく低下することが確認された。
以上のように本実施例によれば、主ノズルの内径（ａ）と主ノズルの出口から構造体の表面までの距離（Ｌ）との比（Ｌ／ａ）が６０〜８００好ましくは７０〜８００の場合に、補助ノズルから噴射されたジェット流の運動エネルギーを低下させず大きな表面改質効果を得ることができることが明らかになった。
【００４９】
以上説明したように、実施例３６〜５５及び比較例２から、比（ｈ／ａ）が１０〜５００好ましくは２０〜４００の場合に、補助ノズルから噴射されたジェット流の運動エネルギーを低下させず大きな表面改質効果を得ることができることが明らかになった。また、実施例５６〜７５及び比較例３〜４から、比（Ｌ／ａ）が６０〜８００好ましくは７０〜８００の場合に、補助ノズルから噴射されたジェット流の運動エネルギーを低下させず大きな表面改質効果を得ることができることが明らかになった。図３に示すように、主ノズルの出口から補助ノズルの出口までの距離Ｓ＝Ｌ−ｈの関係があることから、主ノズルの内径（ａ）と主ノズルの出口から補助ノズルの出口までの距離（Ｓ）との比（Ｓ／ａ）の好ましい範囲は、Ｌ／ａ−ｈ／ａ＝（７０〜８００）−（２０〜４００）＝５０〜４００であることが算出できる。
【００５０】
【発明の効果】
以上のように、本発明の構造体の表面改質方法によれば、以下のような有利な効果が得られる。
請求項１に記載の発明によれば、
（１）ノズル比（ｂ／ａ）が３〜１５に設定されているので、主ノズルから噴射された高圧水の液柱表面と補助ノズルの内周面とに適度の間隙が形成され、補助ノズルに流入された高圧水は、低圧室に吸引された空気の気流との間に生じる剪断力によって微粒化され効率良く液滴化されるので、高圧水の圧力エネルギーが液滴の運動エネルギーに効率良く変換されエネルギー効率に優れた構造体の表面改質方法を提供することができる。
（２）低圧になった低圧室に吸引された空気は、噴射された高圧水に随伴されて気流を形成するので、高圧水が形成するジェット流の界面で空気とジェット流間の相対速度を小さくしてジェット流が広がるのを防止して収束性を高め単位断面積あたりの液滴のエネルギーを高めることができる構造体の表面改質方法を提供することができる。
（３）低圧室に空気が吸引されることにより空気と液滴の混相流が形成され液滴を含む混相流の体積が増加し、補助ノズル内の圧力が高まりエネルギーが増加し液滴が加速されるので、高圧水の圧力が低くても液滴の運動エネルギーを増加させエネルギー効率を高めることができ、従来の高圧水より低い圧力で極めて高い表面改質効果が得られる構造体の表面改質方法を提供することができる。
（４）高圧水の圧力が２５〜１５０ＭＰａ好ましくは３０〜１００ＭＰａの低圧力にあるので、水を加圧する大型の高圧ポンプを必要とせず汎用性に優れた構造体の表面改質方法を提供することができる。
（５）高圧水の圧力が低いので主ノズル等の磨耗が少なく耐久性に優れるとともに部品交換等を頻繁に行う必要がなくメンテナンスも容易で作業性に優れた構造体の表面改質方法を提供することができる。
（６）高圧水の圧力が低いので構造体に液滴化された高圧水を噴射したときの反動が少なく、作業者は多大な力を要さずに主ノズルや補助ノズルを保持することができ操作性に優れた構造体の表面改質方法を提供することができる。さらに、ロボット等の設備を用いて自動化する際でも、反動が少ないのでノズルの保持具を大型化する必要がなく設備を小型化・軽量化することができ省力化等が容易な構造体の表面改質方法を提供することができる。
（７）主ノズルの内径（ａ）と主ノズルの出口から構造体の表面までの距離（Ｌ）との比（Ｌ／ａ）が６０〜８００好ましくは７０〜８００で形成されているので、主ノズルから噴射された高圧水の圧力エネルギーを液滴の運動エネルギーに効率良く変換して大きな表面改質効果を得ることができる構造体の表面改質方法を提供することができる。
【００５１】
請求項２に記載の発明によれば、請求項１の効果に加え、
（１）低圧室に空気導入部が形成されているので、空気導入部から低圧室内に所定量の空気をスムーズに導入することができ、空気導入部から導入された空気によって液柱が微細に分裂されて液滴化が進行し液滴のジェット流のエネルギーを増大させ、さらに空気と液滴の混相流の体積が増加することにより補助ノズル内の圧力が高まり液滴の速度を高め、液滴の運動エネルギーが低下するのを防止することができるエネルギー効率に優れた液滴噴射ノズルを提供することができる。
【００５２】
請求項３に記載の発明によれば、請求項１又は２の効果に加え、
（１）水を電気分解して得られた還元水を用いることによって、構造体の表面の脱脂ができ、構造体が鋼板や棒状鋼等の金属製で形成されると構造体の表面が還元されて防錆効果が得られるとともに構造体の表面が不動態化して耐酸化性を向上させ赤錆の発生を防止することができ防食性に優れ、また、構造体の乾燥時にマクロセル、ミクロセル化による腐食電池の形成を防止し発錆を防止することができる構造体の表面改質方法を提供することができる。
（２）水を電気分解して得られた還元水は、空気中に放置しておくと酸化され酸化還元電位が低下して還元力が低下するとともに中性化されるため、排水処理設備等を要さない構造体の表面改質方法を提供することができる。
【００５３】
請求項４に記載の発明によれば、請求項３の効果に加え、
（１）ヒドラジン等の電解質は有害であり、また、塩化ナトリウム等の電解質を添加すると還元水中の残留塩素濃度等が高まり、構造体の表面に残留した残留塩素等によって構造体が腐食され易く錆の発生を抑制でき、さらに洗浄後に表面に塗膜を形成する際の密着性等に悪影響を及ぼすのを防止できる構造体の表面改質方法を提供することができる。
【図面の簡単な説明】
【図１】 実施の形態１における液滴噴射ノズルの要部断面斜視図
【図２】 実施の形態１における液滴噴射ノズルの要部断面図
【図３】 実施の形態２における液滴噴射ノズルの要部断面図
【図４】 ノズル比（ｂ／ａ）と重量減少量との関係を示した図
【図５】 ノズル比Ｘ（ｂ／ａ）と空気混合比Ｙ（ｃ／ｄ）との関係を示した図
【図６】 主ノズルの内径（ａ）と補助ノズルの出口から構造体の表面までの距離（ｈ）との比（ｈ／ａ）と重量減少量との関係を示した図
【図７】 主ノズルの内径（ａ）と主ノズルの出口から構造体の表面までの距離（Ｌ）との比（Ｌ／ａ）と重量減少量との関係を示した図
【符号の説明】
１，１ａ 液滴噴射ノズル
２ 本体
３ 低圧室
４ 主ノズル
５ 高圧水管
６ 高圧水流路
７ 補助ノズル
８ 補助ノズル固定部
９ 構造体
１０ 空気導入部[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a surface modification method for a structure, in which droplets of a jet stream that are atomized by jetting high-pressure water under pressure are collided with the structure, and the surface of the structure is cleaned, suspended, etc. It is about.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, various techniques are known for performing surface modification such as cleaning and suspension of a surface of a structure by causing droplets atomized by high-pressure water to collide with the structure.
  As a conventional technique, (Patent Document 1) states that “a second nozzle is provided concentrically at a position downstream of the first nozzle, and a turbulent water jet generated from the first nozzle by pressurizing water is second. A method of generating a water jet that is rectified by a nozzle is disclosed.
[0003]
  According to (Patent Document 2), “a liquid jet pressurized to a high pressure is jetted out as a jet, and a high-pressure gas is mixed into the jet to collide with the material to process, cut or clean the material. Material processing methods "are disclosed.
[0004]
[Patent Document 1]
  JP-A-6-262597
[Patent Document 2]
  Japanese Patent No. 2717241
[0005]
[Problems to be solved by the invention]
  However, the above conventional techniques have the following problems.
(1) (Patent Document 1) describes that the hole diameter of the second nozzle is formed larger than the hole diameter of the first nozzle. In the embodiment, the hole diameter of the first nozzle is 0.17 cm, The hole diameter of the second nozzle is 0.4 cm. However, when a jet stream is generated from the apparatus including the first nozzle and the second nozzle and sprayed onto the structure, the problem is that the energy is low and rust or foreign matter on the surface of the structure may not be removed. Had.
(2) In addition, in order to increase the energy of the jet stream, the water must be brought to a very high pressure at the first nozzle, a large pressure pump is required, and the wear of the first nozzle is extremely frequently changed. It had the subject that it had to be complicated.
(3) The technique disclosed in (Patent Document 2) has a problem that a high-pressure gas must be mixed in a jet jetted from a nozzle, and the apparatus becomes complicated.
[0006]
  The present invention solves the above-described conventional problems, and the liquid column is efficiently formed into droplets by the shearing force generated between the liquid nozzle and the air flow generated in the vicinity of the inner peripheral surface of the auxiliary nozzle. High energy efficiency even if the pressure of high pressure water is lower than conventionalsoAn object of the present invention is to provide a surface modification method for a structure that can be formed into droplets, can efficiently modify the surface of the structure, and is excellent in energy efficiency.
[0007]
[Means for Solving the Problems]
  To solve the above conventional problems, the present inventionofThe structure surface modification method has the following configuration.
[0008]
  According to claim 1 of the present inventionSurface modification method of structureIsA main body, a low pressure chamber formed in the main body, a main nozzle having an inner diameter a that is disposed in a predetermined portion of the low pressure chamber and injects high pressure water into the low pressure chamber, and the low pressure chamber downstream of the main nozzle And an auxiliary nozzle having an inner diameter b that is arranged concentrically with the main nozzle and jets a jet flow, and a nozzle ratio (b / a) that is a ratio of an inner diameter a of the main nozzle and an inner diameter b of the auxiliary nozzle ) Is 3-15From the main nozzle of the droplet jet nozzle,High pressure water of 25 to 150 MPa was disposed on the downstream side of the main nozzle.SaidInjected toward the auxiliary nozzle to form droplets and injected into the structureThe ratio (L / a) between the inner diameter (a) of the main nozzle and the distance (L) from the outlet of the main nozzle to the surface of the structure is 70 to 800.It has a configuration.
  With this configuration, the following effects can be obtained.
(1) When high pressure water is injected from the main nozzle into the low pressure chamber and then flows into the auxiliary nozzle, the low pressure chamber becomes low pressure. Nozzle ratio (b / a)3-15Therefore, an appropriate gap is formed between the surface of the liquid column of high-pressure water ejected from the main nozzle and the inner peripheral surface of the auxiliary nozzle, and air flows from the outlet of the auxiliary nozzle toward the low-pressure chamber in this gap. Sucked. The high-pressure water that has flowed into the auxiliary nozzle is atomized and efficiently formed into droplets by the shearing force generated between the air flow sucked into the low-pressure chamber, so that the pressure energy of the high-pressure water is the kinetic energy of the droplets. It is converted efficiently and has excellent energy efficiency.
(2) Since the air sucked into the low-pressure chamber, which has become low pressure, is accompanied by the jetted high-pressure water to form an air flow, the relative velocity between the air and the jet flow is changed at the interface of the jet flow formed by the high-pressure water. Since the size is reduced, it is possible to prevent the jet stream from spreading and improve the convergence, thereby increasing the energy of the droplets per unit cross-sectional area. This is because jetting a jet flow into still air increases the relative velocity between the air and the jet flow at the jet flow interface, disturbs the flow, and deteriorates convergence.
(3) When air is sucked into the low pressure chamber, a multiphase flow of air and droplets is formed, and the volume of the multiphase flow including the droplets increases. As a result, the pressure in the auxiliary nozzle increases and the energy increases and the droplets are accelerated. Therefore, even if the pressure of the high-pressure water is low, the kinetic energy of the droplets can be increased and the energy efficiency can be increased.
(4) Set the nozzle ratio (b / a)3-15Thus, an extremely high surface modification effect can be obtained at a pressure lower than that of conventional high-pressure water.
(5) Since the pressure of the high pressure water is 25 to 150 MPa, preferably a low pressure of 30 to 100 MPa, a large high pressure pump for pressurizing the water is not required.
(6) Since the pressure of the high-pressure water is low, wear of the main nozzle and the like is low and the durability is excellent, and it is not necessary to frequently replace parts and the maintenance is easy and the workability is excellent.
(7) Since the pressure of the high-pressure water is low, there is little reaction when jetting high-pressure water that has been formed into droplets onto the structure, and the operator can hold the main nozzle and auxiliary nozzle without requiring a great deal of force. And excellent operability. Further, even when automation is performed using equipment such as a robot, there is little reaction, so there is no need to increase the size of the nozzle holder, and the equipment can be reduced in size and weight.
(8) The high-pressure water jetted from the main nozzle is sheared with the air sucked into the auxiliary nozzle. Although droplet formation proceeds by force, the velocity of the droplet tends to decrease due to air resistance as it moves away from the main nozzle. For this reason, the kinetic energy of the jet flow ejected from the main nozzle is maximized at a predetermined distance from the outlet of the main nozzle, and tends to decrease when the kinetic energy is exceeded. On the other hand, as the inner diameter of the main nozzle becomes smaller, the high-pressure water ejected from the main nozzle tends to become droplets. Therefore, in order to obtain a large surface modification effect by the high-pressure water jetted from the main nozzle, the ratio (L) between the inner diameter (a) of the main nozzle and the distance (L) from the outlet of the main nozzle to the surface of the structure / A) must be set to a predetermined range. Since the ratio (L / a) is 70 to 800, the pressure energy of the high-pressure water jetted from the main nozzle can be efficiently converted into the kinetic energy of the droplets to obtain a large surface modification effect. .
[0009]
  Here, as the nozzle ratio (b / a) becomes smaller than 3, the gap between the surface of the liquid column of high-pressure water and the inner peripheral surface of the auxiliary nozzle is small, and the liquid column is greatly affected by the inner peripheral surface of the auxiliary nozzle. In addition, it is difficult for air to be sucked into the low-pressure chamber and the shearing force between the air and the liquid is less likely to be formed into droplets. The gap between the peripheral surface is large and the pressure drop in the low-pressure chamber is low, and the amount of air sucked is reduced. At the interface, the relative velocity between the air and the jet flow increases, the flow becomes turbulent, the convergence is deteriorated, and the energy of the droplets tends to disperse. There is a tendency to decrease, The kinetic energy of the ink droplet by air resistance tends to decrease in et. In particular, when the nozzle ratio (b / a) is smaller than 2 or larger than 25, these tendencies are remarkable, and neither is preferable.
[0010]
  The inner diameter of the main nozzle is suitably 0.2 to 2.0 mm, preferably 0.45 to 1.5 mm. As the inner diameter of the main nozzle becomes smaller than 0.45 mm, the diameter of the liquid column to be ejected becomes smaller, so the area of the structure that can be surface-modified per unit time tends to be small, and the processing efficiency tends to decrease. As the flow rate increases, the flow rate of high-pressure water increases and the high-pressure pump that pressurizes the water tends to increase in size. In particular, when the inner diameter is smaller than 0.2 mm or larger than 2.0 mm, these tendencies are remarkable, so that neither is preferable.
[0011]
  When the inner peripheral surface of the main nozzle is expanded toward the auxiliary nozzle, the liquid column to be ejected can be widened and droplet formation can be promoted, and the structure can be surface-modified per unit time. This is preferable because the area can be increased.
[0012]
  Structures include steel, stainless steel, cast steel, forged steel, etc., steel plates and rod-like steels formed into plate-like, rod-like, tubular, etc., and their surfaces plated with zinc, tin, etc. Welded steel, vehicles such as cars and trains, ships, bridges, steel towers, heaters, boilers, steam generators, inner and outer surfaces, made of reinforced concrete, stones, A structure or a grindstone formed of an inorganic material such as ceramics is used.
[0013]
  As the surface modification, there is used a method in which a jet of droplets collides with a surface of a structure or a foreign matter attached to the surface, and the surface of the structure is removed by excavation or the like. For example, cleaning to remove rust and foreign matter on the surface of the structure, removing paint and concrete deterioration layers on the surface of the structure, and wear layers on the surface of the grindstone, improving the adhesion between the surface of the structure and the paint For example, formation of an anchor pattern and removal of an oxide film at a welded portion are used.
[0014]
  As the pressure of the high-pressure water becomes smaller than 30 MPa, the pressure energy of the high-pressure water becomes smaller, so that the kinetic energy of the droplet tends to be small and the surface modification effect tends to be small. In addition to the tendency, there is a tendency that the rebound when droplets are ejected onto the structure is large and the operability tends to decrease. In particular, when the pressure is smaller than 25 MPa or larger than 150 MPa, these tendencies become remarkable. It is not preferable.
[0015]
  As the ratio (L / a) between the inner diameter (a) of the main nozzle and the distance (L) from the outlet of the main nozzle to the surface of the structure becomes smaller than 70, the amount of high-pressure water droplets decreases. There is a tendency for the surface modification effect of the structure to be reduced, and if it is less than 60, this tendency becomes significant, which is not preferable. Also, as the velocity exceeds 800, the velocity of the liquid droplets decreases due to air resistance, and the kinetic energy decreases, so that the surface modification effect of the structure tends to decrease, which is not preferable.
[0016]
  One or a plurality of droplet ejection nozzles can be provided. By disposing a plurality, it is possible to increase the area of the structure that can be surface-modified per unit time and improve the processing efficiency.
[0017]
  Further, the ratio (h / a) between the inner diameter (a) of the main nozzle and the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure is 10 to 500, preferably 20 to 400. The following effects can be obtained.
(1) The droplets of high-pressure water ejected from the auxiliary nozzle spread and disperse outward as they move away from the outlet of the auxiliary nozzle, and the droplet velocity tends to decrease due to air resistance as they move away from the outlet of the auxiliary nozzle. It is done. Further, the liquid column of high-pressure water that has not been formed into droplets in the auxiliary nozzle is formed into droplets by the shearing force of air after being ejected from the auxiliary nozzle. Therefore, the kinetic energy of the jet flow ejected from the auxiliary nozzle becomes maximum at a predetermined distance from the outlet of the auxiliary nozzle, and tends to decrease when it exceeds the kinetic energy. On the other hand, as the inner diameter of the main nozzle becomes smaller, the high-pressure water ejected from the main nozzle tends to become droplets. Therefore, in order to obtain a large surface modification effect by the jet flow injected from the auxiliary nozzle, the ratio (h) between the inner diameter (a) of the main nozzle and the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure / A) must be set to a predetermined range. Since the ratio (h / a) is 10 to 500, preferably 20 to 400, a large surface modification effect can be obtained without reducing the kinetic energy of the jet flow injected from the auxiliary nozzle.
[0018]
  Here, as the ratio (h / a) between the inner diameter (a) of the main nozzle and the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure becomes smaller than 20, the amount of high-pressure water droplets decreases. There is a tendency that the surface modification effect of the structure due to the liquid droplets is small, and as the surface becomes larger than 400, the speed of the liquid droplets decreases due to the air resistance, and the kinetic energy decreases and the surface modification effect of the structure is small. Is seen. In particular, when the value is smaller than 10 or larger than 500, these tendencies become remarkable, which is not preferable.
[0019]
  The ratio (S / a) of the inner diameter (a) of the main nozzle of the droplet ejection nozzle to the distance (S) from the outlet of the main nozzle to the outlet of the auxiliary nozzle is 50 to 400. If it has, the following effects are obtained.
(1) The high-pressure water jetted from the main nozzle is made into droplets by shearing force between the air sucked into the auxiliary nozzle. In the auxiliary nozzle, the volume of the mixed-phase flow of sucked air and droplets increases, so the pressure in the auxiliary nozzle increases and the droplet velocity increases. There is a tendency for the maximum to be reached at a given distance from the exit and to decrease beyond that. In addition, since the velocity of the jet flow injected from the auxiliary nozzle decreases due to air resistance as it moves away from the outlet of the auxiliary nozzle, in order to obtain a large surface modification effect of the structure, the outlet of the auxiliary nozzle is changed from the outlet of the main nozzle. There is an optimal distance up to. On the other hand, as the inner diameter of the main nozzle becomes smaller, the high-pressure water ejected from the main nozzle tends to become droplets. Therefore, in order to obtain a large surface modification effect of the structure by the high-pressure water jetted from the main nozzle, the inner diameter (a) of the main nozzle and the distance (S) from the outlet of the main nozzle to the outlet of the auxiliary nozzle It is necessary to set the ratio (S / a) within a predetermined range. Ratio (S / a) is Since it is formed with 50 to 400, a large surface modification effect can be obtained by the kinetic energy of the jet flow injected from the auxiliary nozzle.
[0020]
  Here, as the ratio (S / a) between the inner diameter (a) of the main nozzle and the distance (S) from the outlet of the main nozzle to the outlet of the auxiliary nozzle becomes smaller than 50, the amount of high-pressure water droplets decreases. There is a tendency that the surface modification effect of the structure due to the droplets is small, and as the speed increases above 400, the velocity of the droplets ejected from the auxiliary nozzle decreases due to the air resistance, and the kinetic energy becomes small, resulting in surface modification of the structure. This is not preferable because the quality effect tends to be small.
[0021]
  The invention according to claim 2 of the present invention isA method for surface modification of a structure according to claim 1,The low-pressure chamber includes an air introduction portion penetrating the main body.It has a configuration.
  With this configuration, in addition to the operation obtained in the first aspect, the following operation can be obtained.
(1) When high pressure water is injected from the main nozzle into the low pressure chamber and then flows into the auxiliary nozzle, the low pressure chamber becomes low pressure. Since the air introduction portion is formed in the low pressure chamber, a predetermined amount of air can be smoothly introduced from the air introduction portion into the low pressure chamber..The liquid column is finely divided by the air introduced from the air introduction part, and droplet formation proceeds to increase the energy of the jet flow of the droplet, and further assist by increasing the volume of the mixed phase flow of air and droplet It is possible to prevent a drop in the kinetic energy of the droplet by increasing the pressure in the nozzle and increasing the velocity of the droplet.
[0022]
  In additionThe air mixing ratio Y, which is the ratio of the nozzle ratio X (b / a) and the flow rate (c) of air introduced from the air introduction section and entrained in the high pressure water to the flow rate (d) of the high pressure water (C / d) has a configuration in the relationship of (Equation 2)And the following effects are obtained:.
[Expression 2]

(1) When high pressure water is injected from the main nozzle into the low pressure chamber and then flows into the auxiliary nozzle, the low pressure chamber becomes low pressure. Since the air introduction portion is formed in the low pressure chamber, a predetermined amount of air can be smoothly introduced from the air introduction portion into the low pressure chamber. Further, since the air mixing ratio Y of the air introduced from the air introduction part is in the relationship indicated by the nozzle ratio X (Equation 2), the liquid column is finely divided by the air introduced from the air introduction part to form droplets. To increase the energy of the jet flow of the droplets, and further increase the volume of the multiphase flow of air and droplets, increasing the pressure in the auxiliary nozzle and increasing the velocity of the droplets, decreasing the kinetic energy of the droplets Can be prevented.
(2) By determining the nozzle ratio and the flow rate of high-pressure water, it is possible to easily and quickly determine the optimal flow rate of air introduced from the air introduction section into the low-pressure chamber. An efficient nozzle can be manufactured reliably, and it is excellent in productivity, and a product yield can be raised.
[0023]
  Here, (Equation 2) is the ratio of the nozzle ratio X (b / a) to the flow rate (c) of the high-pressure water introduced from the air introduction section and entrained in the high-pressure water (d). It is an equation that defines the optimum range in which the relationship between the air mixing ratio Y (d / c) is obtained from experiments and the surface of the structure can be modified by the ejected droplets. Note that f is a constant determined by the pressure of the high-pressure water, the length of the auxiliary nozzle, and the like.
  It is presumed that the air mixing ratio Y is proportional to the 1.7th power of the nozzle ratio X for the following reason. Air entrained in the high-pressure water enters the auxiliary nozzle through a gap between the outer periphery of the liquid column ejected from the main nozzle and the inner peripheral surface of the auxiliary nozzle. The cross-sectional area of the gap is approximately proportional to the square of the nozzle ratio (b / a), and when the flow rate (d) of high-pressure water is constant, the air flow rate (c) is the cross-sectional area of the gap, that is, the nozzle ratio (b / A) is approximately proportional to the square. However, when the liquid column is ejected from the main nozzle, it spreads outward and the gap between the outer periphery of the liquid column and the inner peripheral surface of the auxiliary nozzle is reduced. Further, since loss occurs due to friction between the entrained air and the inner peripheral surface of the auxiliary nozzle, the air mixing ratio Y is proportional to the 1.7th power, which is slightly smaller than the square of the nozzle ratio X.
[0024]
  In (Expression 2), as f becomes smaller than 0.2, the flow rate of air entrained in high-pressure water is small, and the liquid column does not sufficiently form droplets, so that the kinetic energy of the jet flow of droplets can be increased. However, the surface modification efficiency of the structure tends to decrease, and as f becomes larger than 0.8, the flow rate of air entrained in high-pressure water increases, and the jet flow of droplets is disturbed and the surface modification of the structure is performed. The efficiency tends to decrease or the flow rate of high-pressure water increases with the increase of the flow rate of air entrained in high-pressure water, resulting in a drop in the efficiency of liquid droplets and the removal of rust and foreign matter on the surface of the structure. Since there is a tendency for the surface modification efficiency to decrease, for example, neither is preferable.
[0025]
  Claims of the invention3The invention described in claim 11 or 2The method for surface modification of a structure according to (1), wherein the high-pressure water is reduced water obtained by electrolyzing water.
  With this configuration, the claim1 or 2In addition to the effects obtained with the above, the following actions are obtained.
(1) By using reduced water obtained by electrolyzing water, the surface of the structure can be degreased. When the structure is made of a metal such as a steel plate or rod steel, the surface of the structure is reduced. As a result, the surface of the structure is passivated to improve the oxidation resistance and prevent the occurrence of red rust, and the corrosion resistance is excellent. Further, when the structure is dried, it is possible to prevent formation of a corrosion battery due to the formation of macrocells and microcells and to prevent rusting.
(2) Reduced water obtained by electrolyzing water is oxidized when it is left in the air, the oxidation-reduction potential is lowered, the reducing power is lowered and neutralized. Do not need.
[0026]
  Here, as reduced water obtained by electrolyzing water, water having a pH of 8 to 14, preferably 9 to 12, is preferably used. As the pH becomes lower than 9, the surface of the structure is less likely to be passivated and red rust tends to be generated. As the pH becomes higher than 12, more energy is required to produce reduced water, resulting in lower energy savings. There is a tendency to In particular, when the pH is smaller than 8 or larger than 14, these tendencies are remarkable, and therefore, neither is preferable.
[0027]
  The redox potential of the reduced water is suitably −100 to −900 mV, preferably −200 to −600 mV. When the oxidation-reduction potential is -200 to -600 mV, a high reducing power is obtained, and the structure is easily passivated, and red rust is hardly generated. As the oxidation-reduction potential becomes smaller than -200 mV, the structure tends not to be passivated and red rust tends to be generated depending on the pH. As the oxidation-reduction potential becomes larger than -600 mV, much energy is required for the production of reduced water. However, there is a tendency that the energy saving property is lowered, and furthermore, since the reducing power is strong, it is rapidly oxidized by oxygen in the air and the oxidation-reduction potential tends to be rapidly lowered. In particular, when the oxidation-reduction potential is smaller than −100 mV or larger than −900 mV, these tendencies tend to be remarkable, and neither is preferable.
[0028]
  In addition, when producing | generating reduced water, it is preferable not to add electrolytes, such as sodium chloride, calcium chloride, and hydrazine, to water. Electrolytes such as hydrazine are harmful, and addition of an electrolyte such as sodium chloride increases the residual chlorine concentration in the reduced water, and the structure tends to be corroded by residual chlorine remaining on the surface of the structure, generating rust. This is because it becomes easy and adversely affects the adhesion and the like when a coating film is formed on the surface after washing.
[0029]
  The invention according to claim 4 of the present invention is the surface modification method for a structure according to claim 3, wherein the reduced water is obtained by electrolyzing water to which no electrolyte is added. have.
  With this configuration, in addition to the operation obtained in the third aspect, the following operation can be obtained.
(1) Electrolytes such as hydrazine are harmful, and addition of electrolytes such as sodium chloride increases the residual chlorine concentration in the reduced water, and the structure is easily corroded by residual chlorine remaining on the surface of the structure. Further, it is possible to suppress the occurrence of odors and to adversely affect the adhesion and the like when forming a coating film on the surface after washing.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
  (Embodiment 1)
  FIG. 1 is a cross-sectional perspective view of a main part of a liquid droplet ejecting nozzle according to the first embodiment, and FIG. 2 is a cross-sectional view of a main part of the liquid droplet ejecting nozzle according to the first embodiment.
  In the figure, reference numeral 1 denotes a droplet ejection nozzle in the first embodiment, 2 denotes a cylindrical main body, 3 denotes a cylindrical body having an inner diameter larger than the inner diameter of a main nozzle 4 and an auxiliary nozzle 7 described later inside the main body 2. The formed low pressure chamber 4 is a main nozzle having an inner diameter a disposed on one end side of the low pressure chamber 3, 5 is screwed to one end side of the main body 2, and presses the main nozzle 4 at the end face to be fixed in the main body 2. 6 is a high-pressure water flow path formed at the axial center of the high-pressure water pipe 5, and 7 is concentrically arranged at the other end of the low-pressure chamber 3 on the downstream side of the main nozzle 4 with a predetermined distance from the main nozzle 4. An auxiliary nozzle having an inner diameter b provided, 8 is an auxiliary nozzle fixing portion which is screwed to the other end of the main body 2 and fixes the auxiliary nozzle 7, 9 is a distance h from the outlet of the auxiliary nozzle 7, and an outlet of the main nozzle 4 Vehicles such as automobiles and trains, such as steel plates made of steel, stainless steel, etc., spaced apart from each other by a distance L Vessel or aircraft, bridges and steel towers or the like, a heater, a boiler or the like, a structure formed by reinforced concrete or stone and the like.
  In the first embodiment, the nozzle ratio (b / a), which is the ratio between the inner diameter a of the main nozzle 4 and the inner diameter b of the auxiliary nozzle 7, is 2 to 25, preferably 3 to 15. Further, the ratio (S / a) between the inner diameter a of the main nozzle 4 and the distance (S) from the outlet of the main nozzle 4 to the outlet of the auxiliary nozzle 7 is 50 to 400. Further, the droplet ejection nozzle 1 has a ratio (h / a) between the inner diameter a of the main nozzle 4 and the distance (h) from the outlet of the auxiliary nozzle 7 to the surface of the structure 10, preferably 500 to 500, more preferably 20 to 400. It is arranged at such a position. The ratio (L / a) between the inner diameter a of the main nozzle 4 and the distance (L) from the outlet of the main nozzle 4 to the surface of the structure 9 is 60 to 800, preferably 70 to 800. It is installed.
[0031]
  The operation of the surface modification method for the structure using the droplet jet nozzle in the first embodiment configured as described above will be described below.
  When water is pumped into the high-pressure water flow path 3 and high-pressure water pressurized to a pressure of 25 to 150 MPa, preferably 30 to 100 MPa is injected as a liquid column from the main nozzle 4 with the inner diameter a toward the auxiliary nozzle 5 with the inner diameter b, the low-pressure chamber The inside of 3 becomes low pressure. Since the nozzle ratio (b / a) is 2 to 25, preferably 3 to 15, there is an appropriate gap between the surface of the liquid column of high-pressure water ejected from the main nozzle 4 and the inner peripheral surface of the auxiliary nozzle 7. The air is sucked into the gap from the outlet of the auxiliary nozzle 7 toward the low pressure chamber 3. The high-pressure water that has flowed into the auxiliary nozzle 7 from the main nozzle 4 is atomized and efficiently formed into droplets by a shearing force generated between the air flow sucked into the low-pressure chamber 3. In addition, air sucked into the low pressure chamber 3 forms a mixed phase flow of air and droplets in the auxiliary nozzle 7, increasing the volume of the mixed phase flow, increasing the pressure in the auxiliary nozzle 7, increasing energy, and accelerating the droplets. Is done. Further, the air sucked into the low pressure chamber 3 is accompanied by the high pressure water ejected from the main nozzle 4 to form an air flow, and the relative velocity between the air and the jet flow is reduced. 7 prevents the jet stream from spreading and increases the energy density of the droplets.
  The droplet is ejected as a jet flow from the auxiliary nozzle 7 toward the structure 9 while maintaining high kinetic energy. The droplets ejected from the auxiliary nozzle 7 are washed to remove rust, foreign matter, etc. on the surface of the structure 9, and to remove the deteriorated paint and concrete deteriorated layer on the surface of the structure 9, and the wear layer on the surface of the grindstone. Surface modification is performed.
[0032]
  As described above, since the droplet jet nozzle according to the first embodiment is configured, the following operation is obtained.
(1) Since the nozzle ratio (b / a) is set to 2 to 25, preferably 3 to 15, the high pressure water flowing into the auxiliary nozzle is generated between the air flow sucked into the low pressure chamber. Since it is atomized by the shearing force and efficiently formed into droplets, the pressure energy of high-pressure water is efficiently converted into the kinetic energy of the droplets, and the energy efficiency is excellent.
(2) Since the air sucked into the low-pressure chamber, which has become low pressure, is accompanied by the jetted high-pressure water to form an air flow, the relative velocity between the air and the jet flow is changed at the interface of the jet flow formed by the high-pressure water. It can be made smaller to prevent the jet stream from spreading, improving the convergence and increasing the energy of the droplets per unit cross-sectional area.
(3) When air is sucked into the low pressure chamber, a mixed phase flow of air and droplets is formed, and the volume of the mixed phase flow including the droplets flowing in the auxiliary nozzle increases. As a result, the pressure in the auxiliary nozzle increases and the energy increases and the droplets are accelerated. Therefore, even if the pressure of the high-pressure water is low, the kinetic energy of the droplets can be increased and the energy efficiency can be increased. An extremely high surface modification effect can be obtained at a lower pressure.
(4) The velocity of the droplet in the auxiliary nozzle becomes maximum at a predetermined distance from the outlet of the main nozzle, and when it exceeds that, there is a tendency to decrease due to air resistance, but the ratio (S / a) is 50 to 400 Since it is formed, a large surface modification effect can be obtained by the kinetic energy of the jet flow ejected from the auxiliary nozzle without reducing the kinetic energy of the droplets.
[0033]
  Further, according to the surface modification method of the structure using the droplet jet nozzle in the first embodiment,
(1) Since the pressure of the high-pressure water is 25 to 150 MPa, preferably a low pressure of 30 to 100 MPa, a large high-pressure pump for pressurizing water is not required.
(2) Since the pressure of the high-pressure water is low, wear of the main nozzle and the like is small and the durability is excellent, and it is not necessary to frequently replace parts and the maintenance is easy and the workability is excellent.
(3) Since the pressure of high-pressure water is low, there is little reaction when jetting high-pressure water in droplets onto the structure, and the operator can hold the main nozzle and auxiliary nozzle without requiring great force. And excellent operability. Further, even when automation is performed using equipment such as a robot, there is little reaction, so there is no need to increase the size of the nozzle holder, and the equipment can be reduced in size and weight.
(4) Since the ratio (L / a) between the inner diameter (a) of the main nozzle and the distance (L) from the outlet of the main nozzle to the surface of the structure is 60 to 800, preferably 70 to 800, The pressure energy of the high-pressure water ejected from the main nozzle can be efficiently converted into the kinetic energy of the droplets to obtain a large surface modification effect.
(5) Since the ratio (h / a) between the inner diameter (a) of the main nozzle and the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure is 10 to 500, preferably 20 to 400, A great surface modification effect can be obtained without reducing the kinetic energy of the jet flow injected from the auxiliary nozzle.
[0034]
  In the structure surface modification method described in Embodiment 1, reduced water obtained by electrolyzing water may be used as high-pressure water. As a result, the surface of the structure can be degreased, and when the structure is made of metal, the surface of the structure is reduced to provide a rust prevention effect and the surface of the structure is passivated to be resistant to oxidation. It is possible to prevent the occurrence of red rust and has excellent corrosion resistance. Moreover, the effect | action that it can prevent formation of the corrosion battery by macrocell and microcell formation at the time of drying of a structure, and can prevent rusting is obtained.
[0035]
  (Embodiment 2)
  FIG. 3 is a cross-sectional view of a main part of the droplet jet nozzle in the second embodiment. In addition, the thing similar to what was demonstrated in Embodiment 1 attaches | subjects the same code | symbol, and abbreviate | omits description.
  In the figure, reference numeral 10 denotes an air introduction part that is provided in one or more places of the main body 2 to communicate the outside with the low-pressure chamber 3. In addition, the droplet jet nozzle in Embodiment 2 has a nozzle ratio X (b / a), a flow rate of air introduced from the air introduction unit 10 and entrained in high pressure water (c), and a flow rate of high pressure water (d). The air mixing ratio Y (c / d) that is the ratio of
[Equation 3]

  The difference between the liquid droplet ejecting nozzle of the second embodiment and the first embodiment is that the low pressure chamber 3 has an air introduction part 10 penetrating the main body 2.
[0036]
  Due to the difference in configuration, the droplet ejection nozzle according to the second embodiment can obtain the following operation in addition to the operation described in the first embodiment.
(1) Since the air introduction portion is formed in the low pressure chamber, a predetermined amount of air can be smoothly introduced from the air introduction portion into the low pressure chamber. Furthermore, since the air mixing ratio Y of the air introduced from the air introduction part is in the relationship indicated by the nozzle ratio X (Equation 3), the liquid column is finely divided by the air introduced from the air introduction part to form droplets. To increase the energy of the jet flow of the droplet, and further increase the volume of the mixed phase flow of air and droplets, increasing the pressure in the auxiliary nozzle and increasing the velocity of the droplet, decreasing the kinetic energy of the droplet Can be prevented.
(2) By determining the nozzle ratio and the flow rate of high-pressure water, it is possible to easily and quickly determine the optimal flow rate of air introduced from the air introduction section into the low-pressure chamber. An efficient nozzle can be manufactured reliably, and it is excellent in productivity, and a product yield can be raised.
[0037]
【Example】
  Hereinafter, the present invention will be specifically described by way of examples. The present invention is not limited to these examples.
  (Examples 1-16, Comparative Examples 1-2)
  Experiments were performed to modify the surface of the structure using the droplet jet nozzle described in the second embodiment.
  In the following experiment, in order to measure the flow rate of air introduced from the air introduction unit into the low pressure chamber, a flow meter is connected to the air introduction unit, and the air is introduced from the air introduction unit into the low pressure chamber through the flow meter. It was to so. In addition, an on-off valve is provided in the flow meter, and the on-off valve is closed to prevent air from being introduced into the low-pressure chamber from the air introduction portion. In addition, a flow meter was connected to the high-pressure water channel to measure the flow rate of the high-pressure water. As the structure, a SUS304 stainless steel thin plate with a side length of 40 mm and a thickness of 1 mm is used, and a jet of high-pressure water pressurized to a predetermined pressure is transferred from the main nozzle to five locations on the structure (stainless steel thin plate). Each was sprayed for 1 minute. The weight reduction amount of the structure before and after injection was measured, and the larger the weight reduction amount, the higher the surface modification effect was evaluated.
  The inner diameter (a) of the main nozzle of Examples 1 to 18, the inner diameter (b) of the auxiliary nozzle, the nozzle ratio (b / a), the air flow rate (c) measured by the flow meter, and the high pressure water flow rate (d) Table 1 summarizes the pressure of the high pressure water, the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure, and the weight loss of the structure. The length of the auxiliary nozzle (length from the inlet to the outlet of the auxiliary nozzle) was 80 mm. In Examples 8 to 18, the on-off valve connected to the air introduction unit is closed so that air is not introduced from the air introduction unit into the low-pressure chamber, so the flow rate of air from the air introduction unit is zero.
  FIG. 4 is a graph showing the relationship between the nozzle ratio (b / a) and the weight reduction amount in Examples 1 to 18.
[0038]
[Table 1]

[0039]
  From Table 1 and FIG. 4, it is clear that when the nozzle ratio (b / a) is 2 to 25, particularly 3 to 15, a significant weight reduction can be obtained even when the air flow rate from the air inlet is 0. (Examples 8 to 13). This indicates that the high-pressure water that has flowed into the auxiliary nozzle is atomized by the shearing force generated between the auxiliary nozzle and the airflow sucked into the low-pressure chamber and is efficiently formed into droplets. Inferred. Moreover, it was confirmed that the weight reduction amount can be further increased by opening the on-off valve and introducing air from the air introduction part (Examples 1 to 7). The weight reduction amount of Examples 14 to 18 is smaller than Examples 8 to 13 because the pressure of the high-pressure water is as small as 50 MPa and the distance h from the outlet of the auxiliary nozzle to the structure is different. It was confirmed that the pressure of high-pressure water and the distance h affect the weight loss.
[0040]
  (Examples 19 to 35, Comparative Example 1)
  In Examples 19 to 35 and Comparative Example 1, the inner diameter (a) of the main nozzle, the inner diameter (b) of the auxiliary nozzle, the nozzle ratio (b / a), the air flow rate (c) measured by the flow meter, and the high-pressure water Table 2 summarizes the flow rate (d), the air mixing ratio (c / d), the pressure of the high-pressure water, and the weight loss of the structure. The distance (h) from the outlet of the auxiliary nozzle to the surface of the structure was 15 mm, and the length of the auxiliary nozzle (length from the inlet to the outlet of the auxiliary nozzle) was 80 mm.
  FIG. 5 is a graph showing the relationship between the nozzle ratio X (b / a) and the air mixing ratio Y (c / d) in Examples 19 to 35 and Comparative Example 1.
[0041]
[Table 2]

[0042]
  From Table 2 and FIG. 5, when the relationship between the nozzle ratio X (b / a) and the air mixing ratio Y (c / d) is within the range of (Equation 4), a significant weight reduction can be obtained. confirmed.
[Expression 4]

  As described above, according to the present embodiment, the liquid column is finely divided by the air introduced from the air introduction unit, and droplet formation proceeds to increase the energy of the droplet jet flow. The air sucked into the low-pressure chamber increases the volume of the multiphase flow of air and droplets, thereby increasing the pressure in the auxiliary nozzle and increasing the velocity of the droplets and preventing the kinetic energy of the droplets from decreasing. I guessed it was possible. Therefore, by determining the nozzle ratio and the flow rate of the high-pressure water, the flow rate of the air introduced from the air introduction unit to the low-pressure chamber can be easily and simply determined from the relationship of (Equation 4). It has been clarified that the size, the size and quantity of the air introduction portion can be easily determined, and the design efficiency can be improved and the product yield can be increased.
  In addition, when a pump is connected to the air introduction part and air is press-fitted from the air introduction part to increase the flow rate of air so that f in (Equation 4) is larger than 0.8, the weight of the structure is reduced. The amount was almost zero. This is presumed that as a result of the increase in the air flow rate, the jet flow of the droplets is disturbed and the surface modification efficiency of the structure is reduced.
[0043]
  (Examples 36 to 55, Comparative Example 2)
  In Examples 36 to 55 and Comparative Example 2, the flow rate of air (c) measured with a flow meter, the flow rate of high pressure water (d), the air mixing ratio (c / d), the pressure of high pressure water, the length of the auxiliary nozzle (Length from auxiliary nozzle inlet to outlet), distance from auxiliary nozzle outlet to structure surface (h), main nozzle inner diameter (a) and distance from auxiliary nozzle outlet to structure surface Table 3 summarizes the ratio (h / a) to (h) and the weight loss of the structure. The inner diameter (a) of the main nozzle was 0.45 mm, the inner diameter (b) of the auxiliary nozzle was 2.0 mm, and the distance from the main nozzle outlet to the auxiliary nozzle inlet was 15 mm.
  FIG. 6 shows the ratio (h / a) between the inner diameter (a) of the main nozzle of Examples 36 to 55 and Comparative Example 2 and the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure, and the weight loss. It is the figure which showed the relationship.
[0044]
[Table 3]

[0045]
  From Table 3 and FIG. 6, as the ratio (h / a) between the inner diameter (a) of the main nozzle and the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure is greater than 400, the weight loss is significantly reduced. It was confirmed that there was a tendency to decrease the weight loss as it became smaller than 20.
  As described above, according to this embodiment, the ratio (h / a) between the inner diameter (a) of the main nozzle and the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure is 10 to 500, preferably 20 to In the case of 400, it was found that a large surface modification effect can be obtained without reducing the kinetic energy of the jet flow injected from the auxiliary nozzle.
[0046]
  (Examples 56 to 75, Comparative Examples 3 to 4)
  In Examples 56 to 75 and Comparative Examples 3 to 4, the length of the auxiliary nozzle (length from the inlet of the auxiliary nozzle to the outlet), the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure, The distance (L) from the outlet to the surface of the structure, the ratio (L / a) of the inner diameter (a) of the main nozzle to the distance (L) from the outlet of the main nozzle to the surface of the structure, the pressure of high pressure water, Table 4 summarizes the weight loss of the structure. The inner diameter (a) of the main nozzle was 0.45 mm, the inner diameter (b) of the auxiliary nozzle was 2.0 mm, and the distance from the main nozzle outlet to the auxiliary nozzle inlet was 15 mm. Moreover, the on-off valve connected to the air introduction part was fully opened.
  FIG. 7 shows the ratio (L / a) between the inner diameter (a) of the main nozzles of Examples 56 to 75 and Comparative Examples 3 to 4 and the distance (L) from the outlet of the main nozzle to the surface of the structure and the weight reduction amount. It is the figure which showed the relationship.
[0047]
[Table 4]

[0048]
  From Table 4 and FIG. 7, as the ratio (L / a) between the inner diameter (a) of the main nozzle and the distance (L) from the outlet of the main nozzle to the surface of the structure is greater than 800, the weight loss decreases. , It was confirmed that the weight loss decreased as it became smaller than 70, and it decreased remarkably when it became smaller than 60.
  As described above, according to this embodiment, the ratio (L / a) between the inner diameter (a) of the main nozzle and the distance (L) from the outlet of the main nozzle to the surface of the structure is 60 to 800, preferably 70 to 800. In the case of 800, it became clear that a large surface modification effect can be obtained without reducing the kinetic energy of the jet flow injected from the auxiliary nozzle.
[0049]
  As described above, from Examples 36 to 55 and Comparative Example 2, when the ratio (h / a) is 10 to 500, preferably 20 to 400, the kinetic energy of the jet flow injected from the auxiliary nozzle is reduced. It became clear that a large surface modification effect could be obtained. Further, from Examples 56 to 75 and Comparative Examples 3 to 4, when the ratio (L / a) is 60 to 800, preferably 70 to 800, the kinetic energy of the jet flow injected from the auxiliary nozzle is large without decreasing. It was revealed that the surface modification effect can be obtained. As shown in FIG. 3, since there is a relationship S = L−h from the outlet of the main nozzle to the outlet of the auxiliary nozzle, the inner diameter (a) of the main nozzle and the outlet from the main nozzle to the outlet of the auxiliary nozzle A preferable range of the ratio (S / a) to the distance (S) can be calculated as L / a−h / a = (70 to 800) − (20 to 400) = 50 to 400.
[0050]
【The invention's effect】
  As described above, the present inventionSurface modification method of structureThe following advantageous effects can be obtained.
  According to the invention of claim 1,
(1) The nozzle ratio (b / a) is3-15Therefore, an appropriate gap is formed between the surface of the liquid column of high-pressure water ejected from the main nozzle and the inner peripheral surface of the auxiliary nozzle, and the high-pressure water flowing into the auxiliary nozzle is sucked into the low-pressure chamber. Since it is atomized by the shearing force generated between the air and the air stream, it is efficiently converted into droplets, so that the pressure energy of high-pressure water is efficiently converted into the kinetic energy of the droplets, resulting in excellent energy efficiency.Surface modification method of structureCan be provided.
(2) Since the air sucked into the low-pressure chamber, which has become low pressure, is accompanied by the jetted high-pressure water to form an air flow, the relative velocity between the air and the jet flow is changed at the interface of the jet flow formed by the high-pressure water. Can be made smaller to prevent the jet stream from spreading, increasing convergence and increasing droplet energy per unit cross-sectional areaSurface modification method of structureCan be provided.
(3) When air is sucked into the low pressure chamber, a mixed phase flow of air and droplets is formed, the volume of the mixed phase flow including the droplets increases, the pressure in the auxiliary nozzle increases, the energy increases, and the droplets accelerate. Therefore, even if the pressure of the high-pressure water is low, the kinetic energy of the droplets can be increased and the energy efficiency can be increased, and an extremely high surface modification effect can be obtained at a pressure lower than that of the conventional high-pressure water.Surface modification method of structureCan be provided.
(4) Since the pressure of the high-pressure water is as low as 25 to 150 MPa, preferably 30 to 100 MPa, a surface modification method for a structure having excellent versatility without requiring a large-sized high-pressure pump for pressurizing water is provided. be able to.
(5) Since the pressure of the high-pressure water is low, there is less wear on the main nozzle, etc., and it is excellent in durability, and there is no need to replace parts frequently, so maintenance is easy and workability is improved. can do.
(6) Since the pressure of the high-pressure water is low, there is little reaction when jetting high-pressure water in droplets onto the structure, and the operator can hold the main nozzle and auxiliary nozzle without requiring great force. In addition, it is possible to provide a method for modifying the surface of a structure having excellent operability. Furthermore, even when automation is performed using equipment such as robots, there is little reaction, so there is no need to increase the size of the nozzle holder, making it possible to reduce the size and weight of the equipment, making it easier to save labor, etc. A modification method can be provided.
(7) Since the ratio (L / a) between the inner diameter (a) of the main nozzle and the distance (L) from the outlet of the main nozzle to the surface of the structure is 60 to 800, preferably 70 to 800, It is possible to provide a surface modification method for a structure that can efficiently convert pressure energy of high-pressure water ejected from a main nozzle into kinetic energy of droplets to obtain a large surface modification effect.
[0051]
  According to invention of Claim 2, in addition to the effect of Claim 1,
(1) Since the air introduction portion is formed in the low pressure chamber, a predetermined amount of air can be smoothly introduced from the air introduction portion into the low pressure chamber.,The liquid column is finely divided by the air introduced from the air introduction part, and droplet formation proceeds to increase the energy of the jet flow of the droplet, and further assist by increasing the volume of the mixed phase flow of air and droplet It is possible to provide a liquid droplet ejecting nozzle excellent in energy efficiency that can prevent a drop in kinetic energy of a liquid droplet by increasing the pressure in the nozzle and increasing the speed of the liquid droplet.
[0052]
  Claim3According to the invention described in claim1 or 2In addition to the effect of
(1) By using reduced water obtained by electrolyzing water, the surface of the structure can be degreased. When the structure is made of a metal such as a steel plate or rod steel, the surface of the structure is reduced. The anti-corrosion effect is obtained and the surface of the structure is passivated to improve oxidation resistance and prevent the occurrence of red rust. It is possible to provide a surface modification method for a structure that can prevent formation of a corrosion battery and prevent rusting.
(2) Reduced water obtained by electrolyzing water is oxidized when it is left in the air, the oxidation-reduction potential is lowered, the reducing power is lowered and neutralized. It is possible to provide a method for modifying the surface of a structure that does not require.
[0053]
  According to invention of Claim 4, in addition to the effect of Claim 3,
(1) Electrolytes such as hydrazine are harmful, and addition of an electrolyte such as sodium chloride increases the residual chlorine concentration in the reduced water, and the structure is easily corroded by residual chlorine remaining on the surface of the structure. Further, it is possible to provide a method for modifying the surface of a structure that can suppress the occurrence of the above-mentioned and prevent adverse effects on the adhesion and the like when forming a coating film on the surface after washing.
[Brief description of the drawings]
FIG. 1 is a cross-sectional perspective view of a main part of a droplet jet nozzle according to a first embodiment.
FIG. 2 is a cross-sectional view of a main part of a droplet jet nozzle according to Embodiment 1.
FIG. 3 is a cross-sectional view of a main part of a liquid droplet ejecting nozzle according to a second embodiment.
FIG. 4 is a graph showing the relationship between the nozzle ratio (b / a) and the weight loss.
FIG. 5 is a diagram showing the relationship between the nozzle ratio X (b / a) and the air mixing ratio Y (c / d).
FIG. 6 is a diagram showing the relationship between the ratio (h / a) between the inner diameter (a) of the main nozzle and the distance (h) from the outlet of the auxiliary nozzle to the surface of the structure and the weight reduction amount.
FIG. 7 is a diagram showing the relationship between the ratio (L / a) between the inner diameter (a) of the main nozzle and the distance (L) from the outlet of the main nozzle to the surface of the structure, and the weight loss.
[Explanation of symbols]
  1,1a Droplet injection nozzle
  2 body
  3 Low pressure chamber
  4 Main nozzle
  5 High pressure water pipe
  6 High-pressure water flow path
  7 Auxiliary nozzle
  8 Auxiliary nozzle fixing part
  9 Structure
  10 Air introduction part

Claims (4)

A main body, a low pressure chamber formed in the main body, a main nozzle having an inner diameter a that is disposed in a predetermined portion of the low pressure chamber and injects high pressure water into the low pressure chamber, and the low pressure chamber downstream of the main nozzle And an auxiliary nozzle having an inner diameter b that is arranged concentrically with the main nozzle and jets a jet flow, and a nozzle ratio (b / a) that is a ratio of an inner diameter a of the main nozzle and an inner diameter b of the auxiliary nozzle ) from the main nozzles of the droplet ejection nozzles 3 to 15, injects high-pressure water 25~150MPa to the structure by spraying with liquid droplets toward the auxiliary nozzle disposed downstream of said main nozzles And the ratio (L / a) between the inner diameter (a) of the main nozzle and the distance (L) from the outlet of the main nozzle to the surface of the structure is 70 to 800 . Surface modification method. The low-pressure chamber, a surface modification method of the structure according to claim 1, characterized in that it comprises an air introduction portion that is formed through the body. The method for surface modification of a structure according to claim 1 or 2 , wherein the high-pressure water is reduced water obtained by electrolyzing water. 4. The surface modification method for a structure according to claim 3, wherein the reduced water is obtained by electrolyzing water to which no electrolyte is added.

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