JP2004353296A

JP2004353296A - Method and device for repairing well

Info

Publication number: JP2004353296A
Application number: JP2003152289A
Authority: JP
Inventors: Hideetsu Kai; 秀悦開; 邦弘 ▲高▼野; Kunihiro Takano
Original assignee: NARIKI KK; OYABE JOKASO KANRI CENTER KK
Current assignee: NARIKI KK; OYABE JOKASO KANRI CENTER KK
Priority date: 2003-05-29
Filing date: 2003-05-29
Publication date: 2004-12-16
Anticipated expiration: 2023-05-29
Also published as: JP4299587B2

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the quantity of water, which is hoisted when sediment is hoisted in the repair of a well, to the utmost, and to collapse even hard buried sediment. <P>SOLUTION: In a method and a device for repairing the well, a closed-end cylinder-shaped recovery case is hung down in the well; a jet of water is emitted downward and obliquely upward from a water injection nozzle which is provided below the recovery case; the buried sediment is scattered by a downward jet flow; the sediment is led upward from the outside of the recovery case by an obliquely upward jet flow, so as to be taken inward, along with the water, from a mouth part on the upside of the recovery case; and the sediment is accumulated inside while the water is discharged outward by a permeable filter which is provided in at least a part of outer and bottom surfaces of the recovery case. In the device for repairing the well, a bottom of the recovery case is formed in a tapered shape in accordance with an ejection angle obliquely upward from the injection nozzle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、井戸内の埋没やストレーナー（取水口）の目づまり等に用いる井戸修繕方法に関する。
【０００２】
【従来の技術】
井戸は、スケール、水垢、泥土、砂によって、底が浅くなったりや目づまり等が起きた場合には、井戸としての機能を回復するために修繕をする。
【０００３】
従来の井戸修繕方法としては、エアーリフト方法、ベーリング方法が知られている（例えば、非特許文献１参照。）。エアーリフト方法は、井戸底に空気を入れて上昇流を起こし、その上昇流によって土砂及び水を一緒に排出する方法である。ベーリング方法は、ベーラーという汲み上げ容器を井戸に入れ、ベーラーを井戸底に押し付けて、ベーラーの底の弁から埋設土砂を取り込み、ベーラーを引き上げて土砂及び水を排出する方法である。
【０００４】
【非特許文献１】
監修：建設省北陸地方建設局道路部、「消・融雪施設の維持管理マニュアル」、発行：消・融雪施設の維持管理マニュアル検討委員会、平成８年３月、ｐ．４１−４４
【０００５】
【発明が解決しようとする課題】
井戸底を元通りの深さにするには、土砂を地上に引き上げれば良いのであるが、上記した二つの方法は何れも、土砂だけでなく水をも一緒に引き上げるので、引き上げ費用が高くなるし、引き上げ後に土砂と水を分離してから廃棄せねばならず、手間がかかる。また、上記した二つの方法は何れも、井戸底に溜まった埋没土砂が硬くなっている場合に、その硬い土砂を崩すことができず、その結果、井戸底を元通りの深さにできない。
【０００６】
本発明の井戸修繕方法及び井戸修繕装置は上記実情を考慮して創作されたもので、その解決しようとする課題は、土砂引き上げ時の水の引き上げ量を出来る限り減らすと共に、硬い埋設土砂をも崩せるようにすることである。
【０００７】
【課題を解決するための手段】
本発明のうち請求項１の発明は、有底筒状の回収ケースを井戸内に吊り下げ、回収ケースよりも下方に有する水噴射ノズルから下方及び斜め上方に水を噴射し、下方に向かう噴射流で埋没土砂を飛散させ、斜め上方に向かう噴射流で回収ケースの外側から上方に土砂を導いて回収ケース上側の口部から内部に土砂を水ごと取り込み、回収ケースの外面と底面の少なくとも一部に備わる透水フィルターによって外部に水を排出しつつ内部に土砂をためることを特徴とする井戸修繕方法である。
【０００８】
請求項２の発明は、フレームの外側及び底側を被覆カバーで覆って有底筒状の回収ケースを形成し、被覆カバーの少なくとも一部に透水フィルターを用い、回収ケース内の上下に水供給パイプを通すと共に、水供給パイプに通じる水噴射ノズルを回収ケースよりも下方に備え、水噴射ノズルからの水の噴射方向を下方及び斜め上方にしてあることを特徴とする井戸修繕装置である。
【０００９】
被覆カバーの少なくとも一部に透水フィルターを用いてあるので、透水フィルターから水が排出される。なお、被覆カバーの全部に透水フィルターを用いれば、効率よく排水できる。
【００１０】
回収ケースの底の角度は、噴射ノズルから斜め上方に向かう噴射角度と異なっていても良いが、斜め上方に向かう噴射流による上昇効果を高めるには、請求項３の発明のように、回収ケースの底が、水噴射ノズルから斜め上方に向かう噴射角度に合わせてテーパー状に形成してあることが望ましい。
【００１１】
【発明の実施の形態】
本発明の井戸修繕装置１は図２に示すように、有底筒状の回収ケース２の外側に井戸への出し入れ用のガイド３を設けると共に、回収ケース２よりも上方から下方に延びる水供給パイプ４を回収ケース２の中央部に支持し、回収ケース２よりも下方に位置する水供給パイプ４の下端に水噴射ノズル５を有するものである。
【００１２】
回収ケース２は図３に示すように、フレーム６の外側及び底側を被覆カバー７としての透水フィルターで覆って有底筒状に形成したものである。
【００１３】
フレーム６は、透水フィルター７を止める枠としての役割と、水供給パイプ４を支持する役割を兼備したものである。具体的には、円形の上枠８と下枠９の間に複数本の連結材１０を円周方向に間隔をあけて接続し、上枠８の内側中央部に上リング１１を有し、上リング１１と上枠８とを放射状に延びる上支持材１２で接続してある。同様に、下枠９の内側中央部に下リング１３を有し、下リング１３と下枠９とを放射状に延びる下支持材１４で接続してある。また、下リング１３の真下には底リング１５を有し、底リング１５と下枠９の間を斜材１６で接続してある。そして、水供給パイプ４を、上、下、底の各リング１１，１３，１５に通すと共に溶接等して水供給パイプ４をフレーム６に一体化してある。
【００１４】
水噴射ノズル５は図４に示すように、水供給パイプ４への接続用のネジ部１７を管状本体１８の上部に有し、プラグ１９を管状本体１８の下部にねじ込み、プラグ１９の中央部には、上下方向に貫通する小さな下向き孔２０をあけてある。同様に、管状本体１８の高さ中間部にも、斜め上向きに貫通する小さな斜め孔２１を円周方向に間隔をあけて設けてある。斜め孔２１の角度は、限定しないが、回収ケース２の底の角度と同じ角度とすることが、斜め孔２１からの噴射流で土砂を回収ケース２の外側から上方に導くには好ましい。また、斜め孔２１の傾斜角度を４５度とすることが、さらに好ましい。
【００１５】
透水フィルター７は、水を外部に排出しつつ土砂を内部にためるもので、フレーム６の外側に接着剤で貼り付けるか、ネジ等の留め具で着脱自在に止める。これによって、回収ケース２の周囲及び底が透水フィルター７で覆われ、回収ケース２の上端が、土砂を取り込む口部２２となる。なお、着脱自在に止めた場合は、透水フィルターの交換作業が迅速に行える。透水フィルターの具体的な一例としては、日本特殊織物株式会社が製造販売している製品名：ＰＥ１００ｍｅｓｈを用いている。ちなみに、その品質は以下の通りである。メッシュカウント：８３×６４（ｉｎｃｈ）、線径：１２２（ｍｉｃｒｏｎ）、オープニング：２２９（ｍｉｃｒｏｎ）、開口率：４３（％）、厚さ：２５５（ｍｉｃｒｏｎ）。
【００１６】
ガイド３は、フレーム６から外側に張り出したもので、上下に延びるバー２３と、バー２３の途中から内向きに突出してフレーム６に溶接等で接続する止め片２４とからなる。井戸Ｈへの回収ケース２の出入りを容易にするために、バー２３の上端部を内側に向かって斜め上向きに屈曲し、対称的にバー２３の下端部を内側に向かって斜め下向きに屈曲してある。この屈曲角度は限定しないが、いずれも４５度とすることが望ましい。ガイド３によって、回収ケース２外面と井戸Ｈ内面との隙間が確保され、この隙間を利用して土砂が上昇する。
【００１７】
水供給パイプ４は図１に示すように、その上端部を超高圧洗浄車２５のホース２６に接続する。超高圧洗浄車２５は、例えば、２６０ｋｇ／ｃｍ^２の噴射圧で水を噴射するもので、タンク内の水を高圧プランジャーポンプでホース２６、水供給パイプ４の順に送り込む。ホース２６には後述するように井戸修繕装置１を吊り下げる力が加わるので、吊り下げに耐えられる強度を有するものを用いる。
【００１８】
図１を参照しながら上述した本発明の井戸修繕装置１の使用方法を説明する。まず、井戸修繕装置１の水供給パイプ４を超高圧洗浄車２５のホース２６に接続する。そして、クレーン車等（図示省略）を用いて井戸修繕装置１を井戸Ｈ内の上部に降ろして吊り下げて支持する。続いて、井戸Ｈの上部に滑車２７を支え（図示省略）によって支持し、滑車２７にホース２６をかける。ホース２６を徐々に超高圧洗浄車２５から引き出して、井戸修繕装置１を井戸Ｈの底に向かって降ろしていく。井戸底に近づいたら、超高圧洗浄車２５から高圧水を井戸修繕装置１に送り込み、水噴射ノズル５から下方及び斜め上方に向かって水を噴射させる。井戸底にたまっている埋没土砂２８は柔らかかろうが、硬く締まっていようが、下向きの噴射流によって飛散する。下向きの噴射水によって井戸底に対流が発生するので、噴射方向の真下部分でなくとも埋没土砂２８は飛散する。また、斜め上向きの噴射流が上昇流として機能することで、飛散した土砂が井戸Ｈ内面と回収ケース２外面の間を通過して上昇し、回収ケース上端の口部２２から土砂が水と一緒に取り込まれる。埋没土砂がなくなれば、超高圧洗浄車２５を駆動してホース２６を巻き取り、井戸修繕装置１を引き上げる。水に浸かっている井戸修繕装置１を引き上げる際にも、水噴射ノズル５から水を噴射することで、斜め上向きの噴射流によって、土砂が水と一緒に回収ケース２の口部２２から取り込まれるだけでなく、ストレーナ等の井戸内面についた水垢もとれ、水垢も水と一緒に回収ケースの口部２２から内部に取り込まれる。なお、引き上げの際に水噴射ノズル５から水を噴射しないと、水供給パイプ４が水圧で潰れて破損するおそれがある。また、回収ケース２を井戸Ｈに溜まった水面よりも引き上げると、透水フィルター７から水が排出され、内部に土砂や水垢等の異物が取り込まれる。
【００１９】
本発明は上記実施形態に限定されない。例えば、井戸修繕装置１のフレーム６にフックを付けてもよい。この場合、地上でウィンチを支持し、ウィンチのワイヤをフックに引っ掛けて、井戸修繕装置１を上昇・下降させることで、ホースにかかる吊り下げ力を小さくできる。また、ガイド３は、溶接せずにネジ等を用いることで着脱可能に設けても良い。
【００２０】
【発明の効果】
本発明の請求項１と２の発明は、下方への噴射水流によって井戸底に対流を発生させ、埋没土砂を飛散させる。従って、埋没土砂が硬いものであっても、噴射流によって埋没土砂を砕くことができる。また、有底筒状の回収ケースの透水フィルターから外部に水を排出するので、土砂引き上げ時の水の引き上げ量が従来よりも減り、土砂等と水を分離する作業が容易になる。回収ケースの外面全域に透水フィルターを用いた場合は、土砂等と水を分離する作業が殆ど不要となる。
【００２１】
請求項３の発明は、回収ケースの底が噴射ノズルから斜め上方に向かう噴射角度に合わせてテーパー状に形成してあるので、斜め上方に向かう噴射流が回収ケースの底に沿うことになって土砂の上昇効果が高まり、土砂の回収時間を短縮できる。
【図面の簡単な説明】
【図１】本発明の井戸修繕方法を示す断面図である。
【図２】本発明の井戸修繕装置を示す斜視図である。
【図３】フレーム、水供給パイプ、噴射ノズルの配置関係を示す斜視図である。
【図４】（イ）（ロ）噴射ノズルの断面図、Ａ−Ａ線断面図である。
【符号の説明】
２回収ケース
４水供給パイプ
５水噴射ノズル
６フレーム
７被覆カバー（透水フィルター）
２２口部
２８埋没土砂
Ｈ井戸[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a well repair method used for burial in a well, clogging of a strainer (water intake), and the like.
[0002]
[Prior art]
When the well becomes shallow or clogged due to scale, scale, mud, or sand, the well is repaired to restore its function as a well.
[0003]
As a conventional well repair method, an air lift method and a baling method are known (for example, see Non-Patent Document 1). The air lift method is a method in which air is introduced into a well bottom to cause an upflow, and the upflow causes soil and water to be discharged together. The baling method is a method in which a pumping vessel called a baler is placed in a well, the baler is pressed against the bottom of the well, buried sediment is taken in from a valve at the bottom of the baler, and the baler is raised to discharge sediment and water.
[0004]
[Non-patent document 1]
Supervision: Ministry of Construction, Hokuriku Regional Construction Bureau Road Department, “Maintenance and Management Manual for Snow Removal and Snow Melting Facilities”, Issued by: Committee for Review of Maintenance and Management Manual for Snow Removal and Snow Melting Facilities, March 1996, p. 41-44
[0005]
[Problems to be solved by the invention]
The bottom of the well can be restored to its original depth by raising the soil to the ground.However, in both of the above methods, not only the soil but also the water is raised together, so the lifting cost is high. In other words, it is necessary to separate the soil and water after lifting and then dispose of it, which is troublesome. In addition, in any of the above two methods, when the buried sediment accumulated in the well bottom is hard, the hard soil cannot be broken, and as a result, the well bottom cannot be restored to the original depth.
[0006]
The well repair method and well repair device of the present invention have been created in consideration of the above-mentioned circumstances, and the problem to be solved is to reduce the amount of pulling up water when pulling up sediment as much as possible and to reduce hard buried sediment. Is to be able to break down.
[0007]
[Means for Solving the Problems]
According to the invention of claim 1 of the present invention, a bottomed cylindrical recovery case is suspended in a well, water is injected downward and obliquely upward from a water injection nozzle provided below the recovery case, and downward injection is performed. The buried earth and sand is scattered by the flow, and the earth and sand are guided upward from the outside of the collection case by the jet flow directed obliquely upward, and the earth and sand are taken into the inside from the mouth on the upper side of the collection case. A well repair method characterized by accumulating earth and sand inside while discharging water to the outside by a water permeable filter provided in a part.
[0008]
According to a second aspect of the present invention, the outer and bottom sides of the frame are covered with a covering cover to form a bottomed cylindrical recovery case, and a water-permeable filter is used for at least a portion of the covering cover, and water is supplied vertically in the recovery case. A well repair device characterized in that a water injection nozzle communicating with a water supply pipe is provided below the recovery case while passing through the pipe, and water is injected downward and obliquely upward from the water injection nozzle.
[0009]
Since the water-permeable filter is used for at least a part of the cover, water is discharged from the water-permeable filter. In addition, if a water-permeable filter is used for all of the cover, drainage can be performed efficiently.
[0010]
The angle of the bottom of the recovery case may be different from the injection angle going obliquely upward from the injection nozzle. Is preferably formed in a tapered shape in accordance with the injection angle obliquely upward from the water injection nozzle.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
As shown in FIG. 2, the well repair apparatus 1 of the present invention has a guide 3 for taking in and out of a well outside a bottomed cylindrical recovery case 2, and a water supply extending downward from above the recovery case 2. The pipe 4 is supported at the center of the recovery case 2, and has a water injection nozzle 5 at the lower end of the water supply pipe 4 located below the recovery case 2.
[0012]
As shown in FIG. 3, the recovery case 2 is formed in a bottomed cylindrical shape by covering the outside and the bottom side of the frame 6 with a water-permeable filter as a cover 7.
[0013]
The frame 6 has both a role as a frame for stopping the water-permeable filter 7 and a role to support the water supply pipe 4. Specifically, a plurality of connecting members 10 are connected between the circular upper frame 8 and the lower frame 9 at intervals in the circumferential direction, and the upper frame 8 has an upper ring 11 at a central portion inside. The upper ring 11 and the upper frame 8 are connected by an upper support member 12 extending radially. Similarly, a lower ring 13 is provided at the center of the inside of the lower frame 9, and the lower ring 13 and the lower frame 9 are connected by a lower support member 14 extending radially. A bottom ring 15 is provided directly below the lower ring 13, and the bottom ring 9 and the lower frame 9 are connected by a diagonal member 16. The water supply pipe 4 is integrated with the frame 6 by passing the water supply pipe 4 through the upper, lower, and bottom rings 11, 13, and 15 and by welding or the like.
[0014]
As shown in FIG. 4, the water injection nozzle 5 has a screw portion 17 for connection to the water supply pipe 4 at an upper portion of the tubular body 18, a plug 19 is screwed into a lower portion of the tubular body 18, and a central portion of the plug 19 is formed. Has a small downward hole 20 penetrating vertically. Similarly, small oblique holes 21 penetrating obliquely upward are also provided in the middle portion of the height of the tubular body 18 at intervals in the circumferential direction. Although the angle of the oblique hole 21 is not limited, it is preferable to set the same angle as the angle of the bottom of the recovery case 2 in order to guide the earth and sand upward from the outside of the recovery case 2 by the jet flow from the oblique hole 21. Further, it is more preferable that the inclination angle of the oblique hole 21 is 45 degrees.
[0015]
The water-permeable filter 7 is for collecting earth and sand inside while discharging water to the outside. The water-permeable filter 7 is attached to the outside of the frame 6 with an adhesive or is detachably fixed with a fastener such as a screw. As a result, the periphery and the bottom of the collection case 2 are covered with the water-permeable filter 7, and the upper end of the collection case 2 becomes the opening 22 for taking in earth and sand. When the filter is detachably attached, the operation of replacing the water-permeable filter can be performed quickly. As a specific example of the water permeable filter, a product name: PE100mesh manufactured and sold by Japan Special Textile Co., Ltd. is used. Incidentally, the quality is as follows. Mesh count: 83 × 64 (inch), wire diameter: 122 (micron), opening: 229 (micron), aperture ratio: 43 (%), thickness: 255 (micron).
[0016]
The guide 3 protrudes outward from the frame 6 and includes a bar 23 extending vertically and a stop piece 24 protruding inward from the middle of the bar 23 and connected to the frame 6 by welding or the like. In order to make it easy for the recovery case 2 to enter and exit the well H, the upper end of the bar 23 is bent obliquely upward toward the inside, and the lower end of the bar 23 is bent obliquely downward toward the inside symmetrically. It is. Although the bending angle is not limited, it is preferable that each bend is 45 degrees. The guide 3 secures a gap between the outer surface of the collection case 2 and the inner surface of the well H, and the earth and sand rise using this gap.
[0017]
The upper end of the water supply pipe 4 is connected to a hose 26 of an ultrahigh-pressure washing car 25 as shown in FIG. The ultra-high pressure washing vehicle 25 injects water at an injection pressure of, for example, 260 kg / cm ² , and sends water in a tank by a high-pressure plunger pump in the order of a hose 26 and a water supply pipe 4. Since a force for suspending the well repair apparatus 1 is applied to the hose 26 as described later, a hose having a strength enough to withstand the suspension is used.
[0018]
A method of using the well repair apparatus 1 of the present invention described above will be described with reference to FIG. First, the water supply pipe 4 of the well repairing device 1 is connected to the hose 26 of the ultrahigh-pressure washing vehicle 25. Then, the well repairing device 1 is lowered to the upper part in the well H by using a crane truck or the like (not shown) and suspended and supported. Subsequently, the pulley 27 is supported on the upper part of the well H by a support (not shown), and a hose 26 is hung on the pulley 27. The hose 26 is gradually pulled out from the ultrahigh-pressure washing vehicle 25 and the well repairing device 1 is lowered toward the bottom of the well H. When approaching the bottom of the well, high-pressure water is sent from the ultrahigh-pressure washing vehicle 25 to the well repairing device 1, and water is jetted downward and obliquely upward from the water jet nozzle 5. The buried earth and sand 28 accumulated on the bottom of the well is scattered by the downward jet flow whether it is soft or tight. Since the convection is generated at the bottom of the well by the downward spray water, the buried earth and sand 28 is scattered even if the convection is not directly below the spray direction. In addition, since the obliquely upward jet functions as an upward flow, the scattered earth and sand rises by passing between the inner surface of the well H and the outer surface of the collection case 2, and the earth and sand are mixed with water from the mouth 22 at the upper end of the collection case. It is taken in. When the buried soil disappears, the ultrahigh-pressure washing car 25 is driven to wind up the hose 26 and the well repairing device 1 is pulled up. When the well repairing device 1 immersed in water is pulled up, the water is injected from the water injection nozzle 5 so that the dirt is taken in together with the water from the mouth 22 of the recovery case 2 by the obliquely upward jet flow. Not only that, the scale attached to the inner surface of the well such as the strainer is removed, and the scale is taken in together with the water from the mouth 22 of the recovery case. If water is not injected from the water injection nozzle 5 during lifting, the water supply pipe 4 may be crushed by water pressure and may be damaged. When the recovery case 2 is raised above the surface of the water accumulated in the well H, water is discharged from the water-permeable filter 7 and foreign matters such as earth and sand and water scale are taken in.
[0019]
The present invention is not limited to the above embodiment. For example, a hook may be attached to the frame 6 of the well repair device 1. In this case, the suspending force applied to the hose can be reduced by supporting the winch on the ground, hooking the wire of the winch on the hook, and moving the well repair device 1 up and down. Further, the guide 3 may be detachably provided by using a screw or the like without welding.
[0020]
【The invention's effect】
According to the first and second aspects of the present invention, convection is generated at the bottom of the well by the downward jet of water, and the buried earth and sand is scattered. Therefore, even if the buried earth and sand is hard, the buried earth and sand can be broken by the jet flow. Further, since water is discharged to the outside from the water permeable filter of the bottomed cylindrical recovery case, the amount of water to be pulled up when pulling up the soil is reduced as compared with the conventional case, and the work of separating the water from the soil and the like becomes easy. When a water-permeable filter is used on the entire outer surface of the recovery case, the work of separating water from earth and sand is almost unnecessary.
[0021]
According to the third aspect of the present invention, since the bottom of the recovery case is formed in a tapered shape in accordance with the injection angle obliquely upward from the injection nozzle, the jet flow obliquely upwardly follows the bottom of the recovery case. The effect of raising the earth and sand is enhanced, and the collection time of the earth and sand can be reduced.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a well repair method according to the present invention.
FIG. 2 is a perspective view showing a well repairing device of the present invention.
FIG. 3 is a perspective view showing an arrangement relationship between a frame, a water supply pipe, and an injection nozzle.
4A and 4B are a cross-sectional view of an injection nozzle and a cross-sectional view taken along line AA.
[Explanation of symbols]
2 Collection case 4 Water supply pipe 5 Water injection nozzle 6 Frame 7 Cover (permeate filter)
22 mouth 28 buried earth and sand H well

Claims

A bottomed cylindrical recovery case (2) is suspended in the well (H), and water is injected downward and obliquely upward from a water injection nozzle (5) provided below the recovery case (2), and headed downward. The buried sediment (28) is scattered by the jet flow, and the sediment is guided upward from the outside of the recovery case (2) by the jet flow obliquely upward and the sediment is taken into the inside from the mouth (22) on the upper side of the recovery case. A method for repairing a well, wherein water is discharged to the outside by a water-permeable filter (7) provided on at least a part of an outer surface and a bottom surface of a recovery case (2), and sediment is accumulated inside the well.

The outer and bottom sides of the frame (6) are covered with a covering cover (7) to form a bottomed cylindrical recovery case (2), and a water-permeable filter is used for at least a part of the covering cover (7). 2) A water supply pipe (4) is passed above and below the water supply pipe (4), and a water injection nozzle (5) communicating with the water supply pipe (4) is provided below the recovery case (2). A well repairing device characterized in that the direction of water injection is downward and obliquely upward.

The well repairing device according to claim 2, wherein the bottom of the recovery case (2) is formed in a tapered shape in accordance with an injection angle obliquely upward from the water injection nozzle (5).