JP2004033598A

JP2004033598A - Electric water heater

Info

Publication number: JP2004033598A
Application number: JP2002197045A
Authority: JP
Inventors: Fumitaka Ogasawara; 小笠原　史太佳; Masashi Kanbara; 神原　政司; Masaharu Ohashi; 大橋　正治; Takashi Wada; 和田　尚
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-07-05
Filing date: 2002-07-05
Publication date: 2004-02-05

Abstract

<P>PROBLEM TO BE SOLVED: To judge correctly whether or not a liquid level reaches a prescribed position. <P>SOLUTION: An electric water heater is provided with a liquid-level tube 14 for showing a liquid level in a water heater vessel, a float 16 which is provided inside the liquid-level tube 14 and moves vertically according to the liquid level, and a liquid level detecting means 17 which is provided on side faces of the liquid-level tube 14 and is composed of a light emitting element 18 and a light receiving element 19. A pair of light visors 20 each having an aperture 21, are installed respectively between the light emitting element 18 and the liquid-level tube 14 and between the liquid-level tube 14 and the light receiving element 19, and only the light which has passed through the aperture 21 out of the light which is emitted from the light emitting element 18, after passing through the central part of the liquid-level tube 14, reaches the light receiving element 19. Thus, even if the float leans to one side in the liquid-level tube 14, the float can shade the light between the light emitting element 18 and the light receiving element 19, thereby securely detecting the liquid level. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は電気湯沸かし器に関し、特に湯沸かし容器の水位を正確に検知する構成に関する。
【０００２】
【従来の技術】
図７は従来の電気湯沸かし器の要部概略断面図であり、図８は電気湯沸かし器の液位検知手段の要部断面図である。図において、１は湯を沸かして保温する湯沸かし容器、２は湯沸かし容器１に蓄えられた液体である水で、２ａはその液面すなわち水面である。
【０００３】
また、３は液位管でその底部は湯沸かし容器の底部と連結されている。４はフロートで遮光性の材料より構成され湯沸かし容器の液面２ａと連動して液位管３内を上下に動き、湯量を使用者に知らせたり、湯の残量がほとんどなく加熱できない状態であることを知らせたりする。５は液位検知手段で発光素子６と受光手段７とより構成されている。また、８はお湯を出湯するための出湯手段であり、９は湯沸かし容器内の水を加熱保温する加熱手段である。
【０００４】
以下、前記構成における作用について述べる。湯沸かし容器１の液面２ａ、すなわち、フロートの位置が液位検知手段５が配置されている位置以外の位置にあるときは発光素子６より発光した光は受光素子７に到達する。また、フロートの位置が液位検知手段５の位置にあるときは発光素子６より発光した光は遮光性のフロート４により遮光され受光素子７に到達しない。すなわち発光素子６からの光が受光素子７に到達しなくなったときに液面が液位検知手段の位置にあることになる。これにより、例えば、液位検知手段５を最下部の空焼き防止液位に設定しておき、出湯により水面が低下しこの位置に到達したとき、すなわち、フロート４が液位管３の最下部に到達したとき、制御部（図示せず）により加熱手段１０を遮断することにより、加熱を中止し空焼きを防止することができる。
【０００５】
【発明が解決しようとする課題】
しかしながら、前記従来の構成では、液位管３の内径とフロート４の外形との差、例えば、内径１０ｍｍの液位管には通常５．８ｍｍのボールが用いられるように寸法差がある。そのため、ボールの位置が中心から外れた場合、図８に示すように発光素子６からの光Ｌは拡散しているために完全に遮断されず一部が漏洩し受光素子７に到達するため、フロート４が液位検知手段５の位置にあることを検知できない。したがって、液位を自動的に検知して種々の制御を正確に行うのは困難であるという問題があった。
【０００６】
本発明は、前記従来の課題を解決するもので、液位が所定の位置に到達しているか否かを正確に判断し、安全性と利便性の向上を図った電気湯沸かし器を提供することを目的としている。
【０００７】
【課題を解決するための手段】
前記従来の課題を解決するために、本発明の電気湯沸かし器は、湯沸かし容器の液位を示す液位管と、液位に応じて上下に可動するフロートと、液位管の側面に対向して設けた発光素子と受光素子とからなる液位検知手段と、前記発光素子と前記受光素子の前面に設けた遮光手段とを備え、前記遮光手段は光を通す隙間を有する構成とした。この構成により、発光手段より発光した光のうち拡散光は遮光され、隙間を通過した光のみがほとんど拡散せずに受光素子に到達する。また、受光素子は発光素子からの直進光のみを受光し、拡散光は遮光する。そのため、発光素子から液位管の中心部を通過してくる光のみを受光するようにすることができる。したがって、液位管に内蔵されたフロートが液位管の中で偏った位置にあっても確実に光を遮断できるので、液位を正確に検知できる。
【０００８】
【発明の実施の形態】
請求項１に記載の発明は、湯を沸かして保温する湯沸かし容器と、前記湯沸かし容器の側面に設け前記湯沸かし容器の液位を示す液位管と、前記液位管の内部に設けられ液位に応じて上下に可動するフロートと、前記液位管の側面に対向して設けた発光素子と受光素子とからなる液位検知手段と、前記発光素子と前記受光素子の前面に設けた遮光手段とを備え、前記遮光手段は光を通す隙間を有する構成とした。この構成により、受光素子は隙間から発し液位管の中心部を通る光のみを受光するので、フロートが液位管の中で偏った位置にあったとしても必ず光を遮断することができる。したがって、液位を正確に検知する事ができる。
【０００９】
請求項２に記載の発明は、特に、請求項１に記載の遮光手段を板状態からなる遮光板とすることにより、簡単な構成で遮光することができる。
【００１０】
請求項３に記載の発明は、特に、請求項１に記載の遮光手段を液位管に備える構成としたことにより、特別な空間を設けることなく簡単に設けることができる。
【００１１】
請求項４に記載の発明は、特に、請求項１に記載の遮光手段を少なくとも液位検知部の周囲を覆う遮光体からなる構成としたことにより、発光素子以外の周囲の光を遮光することができるので検知精度をさらに良くすることができる。
【００１２】
請求項５に記載の発明は、特に、請求項１に記載の遮光手段を液位管を飾る飾り板と一体に設ける構成としたことにより、新たに特別な空間を必要とせず簡単に設けることができる。
【００１３】
請求項６に記載の発明は、特に、請求項１に記載の遮光手段を発光素子と受光素子との少なくともどちらか一方に設ける構成としたことにより、簡単な構成で拡散光を減少でき、フロートによる光の遮断を確実なものにすることができる。
【００１４】
請求項７に記載の発明は、湯を沸かして保温する湯沸かし容器と、前記湯沸かし容器の側面に設け前記湯沸かし容器の液位を示す液位管と、前記液位管の内部に設けられ液位に応じて上下に可動するフロートと、前記液位管の側面に対向して設けた発光素子と受光素子とからなる液位検知手段と、前記発光素子の前面に集光レンズとを備え、前記集光レンズの焦点が、前記液位管の中心と前記受光素子の間の位置となる構成としたことにより、発光素子より発光した光は液位管の中心部を通過するのでフロートによる光の遮断を確実なものにすることができる。
【００１５】
【実施例】
以下、本発明の実施例について、本発明の効果が顕著に発揮される湯沸かし容器と給水容器の２つの容器を有する２容器式の電気湯沸かし器について図面を参照しながら説明する。
【００１６】
図１は本発明の実施例における電気湯沸かし器の液位検知手段の要部断面図であり、図２は同電気湯沸かし器の断面図である。
【００１７】
図２において、１１は収容した水を沸かして保温する湯沸かし容器、１２は湯沸かし容器１１を加熱するための主ヒータと保温するための保温ヒータからなる加熱手段、１３は湯沸かし容器１１の湯を液位管１４を介して出湯口１５から排出するためのポンプである出湯手段、１６は液位管１４内に設けられ液位の上下変動に応じて上下に可動するフロートである。
【００１８】
なお、液位管１４とフロート１６との関係は、液位管１４の内径に対してフロート１６の外形が大きすぎると出湯時、湯が出にくく不便であり、逆にフロート１６の大きさが小さすぎると後述する光遮断性能が悪くなり、水位の検知がしにくくなる。したがって、液位管１４の内径とフロート１６との関係はこれらの事を考慮して設計的に定められる。通常、湯沸かし容器の容量が２リットル程度の電気湯沸かし器では、液位間の内径は１０ｍｍ、フロートとして用いるボールの外形は５．８ｍｍ程度である。
【００１９】
１７は水量検知手段であり、液位管１４に対向して取り付けた発光素子１８と受光素子１９とから構成している。そして、湯沸かし容器１１と液面が同じになる液位管１４の液面レベルを検知することにより湯沸かし容器１１の水位を検知する。１７ａは満水位置に設置した満水検知、１７ｂは給水検知で、水位がこの位置以下になると自動的に給水される。１７ｃは空焚き防止検知で、水位がこの位置以下になると空焚きの危険が生じるので、加熱手段１２を停止し空焚きを防止する。また、２０は本実施例の特徴である光を通す隙間２１を有する遮光手段である遮光板であり、発光素子１８と受光素子１９との前面に設けている。このため、液位管側には発光素子１８からの光のうち遮光板２０の隙間２１を通過した光のみが放射されることになり、ほとんど拡散せず強い指向性を持つようになる。また、受光素子１９の前面に遮光板２０を設けることにより、隙間２１を通過し受光素子１９に到達するのはほとんど直進光であり、拡散光が到達しにくいようにしている。
【００２０】
２２は湯沸かし容器に給水するための水を収容する給水容器、２３は給水容器２２の水を給水管２４を介して湯沸かし容器１１に給水する給水手段である。また、２５は湯沸かし容器１１内の湯温を検知する温度検知手段、２６は使用者が操作して出湯を指示するための出湯スイッチ、２７は出湯スイッチ２６の受付けを許可するためのロック解除スイッチ、２８は止水弁で電気湯沸かし器が転倒などをしたとき、内部の湯がこぼれないようにしたもので、出湯スイッチ２６の操作に連動して開閉する。
【００２１】
以上のように構成された電気湯沸かし器について、以下にその動作作用について説明する。
【００２２】
湯沸かし容器１１が空の状態から給水して行く場合について説明する。電気湯沸かし器に電源を投入すると、制御部（図示せず）は水量検知手段の検知水量が空焚き防止検知１７ｃ以下であるとの信号を受け、給水手段２３を作動し給水を開始する。そして水位が空焚き防止水位である空焚き防止検知１７ｃ以上になると加熱手段１２をＯＮとし加熱を開始する。
【００２３】
さらに、給水を続け水位が上昇し満水検知１７ａに到達すると給水手段２３を停止し給水を終了する。この後も給水された水は温度検知手段２５により沸騰を検知するまで主ヒータまたは主ヒータおよび保温ヒータにより加熱され、沸騰検知以降は保温ヒータにより保温される。この状態から湯沸かし容器１１の湯は適宜使用され、その水位は低下していく。出湯して水位が給水検知１７ｂを下まわると出湯終了後所定時間経過してから給水を開始する。これにより、常に一定量以上の湯を確保することができる。このように自動給水と出湯とを繰り返して利用する。
【００２４】
本実施例では液位検知手段１７による検知は、満水検知１７ａ、給水検知１７ｂおよび空焚き防止検知１７ｃの３ヶ所で行っている。満水検知１７ａは設計上で定めた最大容量で、これ以上に給水されると沸騰時に湯こぼれなどの危険が発生する水位である。給水検知１７ｂは先にも述べたように出湯して水位がこの給水検知１７ｂを下まわると出湯終了後所定時間経過してから給水を開始する水位であり、これにより、常に給水検知１７ｂまでの容量以上の容量の湯を確保することができる。
【００２５】
また、空焚き防止検知１７ｃは水位がこれ以下になると空焚きの危険が生ずる水位であり、したがって、水位がこの空焚き防止検知１７ｃ以下になると加熱手段１２を遮断し、空焚きが発生しないようにしている。
【００２６】
このように、満水検知１７ａと空焚き防止検知１７ｃとは安全上必要な検知であり、給水検知１７ｂは利便性を良くするために必要な検知である。したがって、その検知精度は高いことが必要となる。
【００２７】
以下、液位検知手段の検知精度を高めるための本実施例の構成について図１を用いて説明する。図１において、発光素子１８と受光素子１９とは液位管１４のほぼ中心線上に対向して設けている。また、液位管１４と発光素子１８との間、および、液位管１４と受光素子１９との間に夫々遮光手段である遮蔽板２０を設けている。この遮蔽板２０には隙間２１が設けられており、かつ、夫々の遮光板２０の隙間２１は発光素子１８と受光素子１９とを結ぶ線上に配置している。したがって、発光素子１８からの発光は通常配光角を有し周囲に拡散するが、その光の大部分は遮蔽板２０に遮られてしまい、隙間２１を通過した光Ｌのみが強い指向性を有して液位管１４に向かう。
【００２８】
もし、このとき液位管１４にフロート１６がないならば、光は液位管１４を通過し受光素子１９と液位管１４との間に設けた遮蔽板２０の隙間２１を通過して受光素子１９に到達する。このとき、受光素子１９の前面に設けた遮光板２０は周囲からの拡散光が受光素子１９に入るのを防いでいる。これにより、液位検知手段１７の位置に水位がないこと、すなわち、液で満たされているか、液が無いかどちらかであることがわかる。
【００２９】
また、液位管１４にフロート１６が有れば、図１に示すように、たとえ液位管１４の内径が１０ｍｍであり、フロート１６として用いたボールの外形が５．８ｍｍであり、かつボールが一方に偏っているとしても光路は液位管１４のほぼ中心を通るため光は必ずフロート１６に遮られ受光素子１９に到達しない。これにより、液位検知手段１７の位置に水位があることがわかる。
【００３０】
以上述べたように、本実施例では遮蔽板２０に設けた隙間２１を通して光の発光および受光をしているので、光の散乱とか、屈折などの周囲の複雑な影響を受けず精度良く検知できる。
【００３１】
以上の説明では、遮光板２０を発光素子１８と受光素子１９との前に夫々設けた例について説明したが、発光素子１８の発光が充分強い場合、すなわち、他の光と区別する事ができる場合はどちらか一方に設けるだけであっても何ら差し支えない。また、本実施例の主旨にかなうものであれば、発光素子１８と受光素子１９とを対向させる位置、隙間の形状などについては前述の構成に特に限定されるものではないし、発光素子１８と受光素子１９との前に設けた夫々の遮光板２０および隙間２１が同じ構成でなくてもよいのは勿論である。また、隙間２１は空間でなく透光性のフィルムなどを用いても良い。
【００３２】
以上述べたように本実施例ではフロート１６が光を遮るか否かにより正確に水位を検知する事ができる。したがって、満水検知および空焚き防止検知の位置に必ずフロートが停止する構成にしておけば確実に満水位置および給水位置を検知する事ができるため安全性を確保することができる。また、所定の位置に給水検知を設けておき満水を確認した後、最初に光が遮られたら給水をするようにすることにより自動給水が可能となり利便性を良くする事ができる。
【００３３】
なお、液位が自動給水を行う閾値に達しているかどうかを検出するために、満水位置と給水位置の間に一ヶ所追加して発光素子と受光素子を設ける構成としたが、一ヶ所に限るものではなく、例えば複数箇所に設けることにより、加熱容器内の液位を精度良く検知可能で、検知した液位をもとに液晶表示素子等の表示手段にて液位を表示することも可能で、更には、検知した液位をもとに、加熱手段による加熱保温制御を変える構成とすることにより、沸騰時の検知精度を向上させ沸騰中に蒸気が出続けることを防ぐことも可能である。
【００３４】
また、遮光手段として板状体を用いた場合を説明したがこれに限定されるものではなく、図３に示すように遮光手段として直接液位管１４に印刷または塗装などの遮光膜２９を設け、この遮光膜２９に隙間２９ａを設けてもよい。勿論遮光手段は必要によりどちらか一方であっても良い。
【００３５】
また、図４に示すように遮光手段として少なくとも液位管１４の周囲を覆う遮光体３０からなる構成とし、この遮光体３０に隙間３０ａを設ける構成としてもよい。また、遮光体３０は必要によりどちらか一方であっても良い。なお、液位管１４に飾り板を取り付ける場合は飾り板を遮光板として用いても良い。
【００３６】
また、遮光手段として発光素子１８の発光部分３１に直接塗膜またはキャップを設けて遮光層３２としても良い。図５は遮光層３２としてキャップを被せた場合で、その一部には光が通過する隙間３３を設けている。同様にして、受光素子１９の一部にしか光が入らないようにして指向性を強くしても良い。なお、遮光層として発光部分３１にキャップを被せる場合、発光部分３１とキャップの隙間３２ａとの間に空間３３を設けると光の指向性が強まり好ましい。
【００３７】
以上遮光手段を用いた場合について述べたが、このような方法以外に図６に示すように発光素子１８の前面に集光レンズ３４を設け、発光素子１８から発光した光Ｌが受光素子１９の位置で集光するようにしても良い。これにより、光の拡散を防ぎ、大部分の光が液位管１４の中心部を通り周囲に漏れることを少なくすることができるため、フロート１６により光を確実に遮断することができ、検知精度を高めることができる。なお、集光レンズの設け方としては液位管とレンズとが一体になるように成型しても良い。また、集光レンズ３４の焦点は、受光素子１９の位置に限らず、フロート１６によって遮られやすくなる構成とすることにより効果が出るものであり、例えば、焦点を液位管１４の中心としてもよく、また、液位管１４の中心と受光素子１９の間の位置とすることによっても、効果があることは言うまでも無い。
【００３８】
以上述べたように、遮光手段を用いることにより、液位が所定の位置に到達しているか否かを正確に判断し、安全性と利便性の向上を図ることができる。
【００３９】
なお、本実施例の説明にあたっては湯沸かし容器と給水容器の２つの容器を有する電気湯沸かし器について説明したが、これに限定されるものではなく湯沸かし容器のみの電気湯沸かし器に本発明の構成を用いても同様の効果が得られる。ただし、この場合一般的には給水検知は不要となる。
【００４０】
また、本実施例の説明にあたってはフロートを球体で図示したが、球体に限るものではなく、光遮断性能や出湯時の湯の出る具合に支障が無ければ、どのような形状であっても同様の効果が得られる。
【００４１】
【発明の効果】
以上のように、請求項１〜７に記載の発明によれば、液位が所定の位置に到達しているか否かを正確に判断し、安全性と利便性の向上を図った電気湯沸かし器を提供することができる。
【図面の簡単な説明】
【図１】本発明の一実施例における電気湯沸かし器の液位検知手段の要部断面図
【図２】同電気湯沸かし器の断面図
【図３】同電気湯沸かし器の液位検知手段の要部断面図
【図４】同電気湯沸かし器の液位検知手段の要部断面図
【図５】同電気湯沸かし器の液位検知手段に用いる発光素子の要部部分断面図
【図６】電気湯沸かし器の液位検知手段の要部断面図
【図７】従来の電気湯沸かし器の要部断面図
【図８】同電気湯沸かし器の液位検知手段の要部断面図
【符号の説明】
１１　湯沸かし容器
１４　液位管
１６　フロート
１７　液位検知手段
１８　発光素子
１９　受光素子
２０　遮光板（遮光手段）
２１、２９ａ、３０ａ、３２ａ　隙間
２９　遮光膜（遮光手段）
３０　遮光体（遮光手段）
３２　遮光層（遮光手段）
３５　集光レンズ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric water heater, and more particularly to a structure for accurately detecting a water level in a water heater container.
[0002]
[Prior art]
FIG. 7 is a schematic sectional view of a main part of a conventional electric water heater, and FIG. 8 is a cross sectional view of a main part of a liquid level detecting means of the electric water heater. In the figure, reference numeral 1 denotes a water heater for boiling water to keep the temperature warm, 2 denotes water which is a liquid stored in the water heater 1 and 2a denotes its liquid level, that is, the water surface.
[0003]
Reference numeral 3 denotes a liquid level tube whose bottom is connected to the bottom of the kettle container. Reference numeral 4 denotes a float which is made of a light-shielding material and moves up and down in the liquid level tube 3 in conjunction with the liquid level 2a of the water heater container to notify the user of the amount of hot water or to make it difficult to heat the remaining amount of hot water. Or let them know that there is something. Reference numeral 5 denotes a liquid level detecting means, which comprises a light emitting element 6 and a light receiving means 7. Reference numeral 8 denotes a tapping means for tapping hot water, and reference numeral 9 denotes a heating means for heating and keeping water in a water heater container.
[0004]
Hereinafter, the operation in the above configuration will be described. When the liquid surface 2a of the water heater 1 is at a position other than the position where the liquid level detecting means 5 is disposed, the light emitted from the light emitting element 6 reaches the light receiving element 7. When the position of the float is at the position of the liquid level detecting means 5, the light emitted from the light emitting element 6 is blocked by the light blocking float 4 and does not reach the light receiving element 7. That is, when the light from the light emitting element 6 does not reach the light receiving element 7, the liquid level is at the position of the liquid level detecting means. Thereby, for example, the liquid level detecting means 5 is set to the lowermost anti-bake liquid level, and when the water level drops due to the hot water and reaches this position, that is, when the float 4 is at the lowermost position of the liquid level tube 3, Is reached, the heating unit 10 is shut off by the control unit (not shown), whereby the heating can be stopped and the empty baking can be prevented.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, there is a difference between the inner diameter of the liquid level tube 3 and the outer shape of the float 4, for example, a dimensional difference such that a 5.8 mm ball is usually used for a liquid level tube having an inner diameter of 10 mm. For this reason, when the position of the ball deviates from the center, the light L from the light emitting element 6 is diffused as shown in FIG. The fact that the float 4 is at the position of the liquid level detecting means 5 cannot be detected. Therefore, there is a problem that it is difficult to automatically detect the liquid level and perform various controls accurately.
[0006]
The present invention has been made to solve the above-mentioned conventional problems, and it is an object of the present invention to provide an electric water heater that accurately determines whether or not a liquid level has reached a predetermined position and improves safety and convenience. The purpose is.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems, an electric water heater of the present invention has a liquid level tube indicating a liquid level of a water heater container, a float movable up and down according to the liquid level, and a side facing the liquid level tube. A liquid level detecting means comprising a light emitting element and a light receiving element provided, and a light shielding means provided on a front surface of the light emitting element and the light receiving element are provided, and the light shielding means has a gap through which light passes. With this configuration, of the light emitted from the light emitting means, the diffused light is blocked, and only the light that has passed through the gap reaches the light receiving element without being diffused. The light receiving element receives only the straight light from the light emitting element and blocks the diffused light. Therefore, it is possible to receive only the light passing through the center of the liquid level tube from the light emitting element. Therefore, even if the float built in the liquid level tube is at a position deviated in the liquid level tube, the light can be reliably blocked, so that the liquid level can be accurately detected.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention according to claim 1 is a water heater for boiling water and keeping the temperature warm, a liquid level tube provided on a side surface of the water heater container and indicating a liquid level of the water heater container, and a liquid level tube provided inside the liquid level tube. A float movable up and down in accordance with the above, a liquid level detecting means comprising a light emitting element and a light receiving element provided opposite to a side surface of the liquid level tube, and a light shielding means provided on a front surface of the light emitting element and the light receiving element And the light blocking means has a gap through which light passes. With this configuration, the light receiving element receives only the light emitted from the gap and passing through the center of the liquid level tube, so that the light can be always blocked even if the float is at an uneven position in the liquid level tube. Therefore, the liquid level can be accurately detected.
[0009]
According to the second aspect of the invention, in particular, the light shielding means according to the first aspect is a plate-shaped light shielding plate, so that light can be shielded with a simple configuration.
[0010]
According to the third aspect of the present invention, in particular, since the liquid level tube is provided with the light shielding means according to the first aspect, it can be easily provided without providing a special space.
[0011]
According to a fourth aspect of the invention, in particular, the light shielding means according to the first aspect is configured to include a light shielding body that covers at least a periphery of the liquid level detection unit, so that ambient light other than the light emitting element is shielded. Therefore, the detection accuracy can be further improved.
[0012]
The invention according to claim 5 is particularly advantageous in that the light-blocking means according to claim 1 is provided integrally with a decorative plate for decorating the liquid level tube, so that the light-blocking means can be easily provided without requiring any special space. Can be.
[0013]
According to a sixth aspect of the present invention, the light shielding means of the first aspect is provided on at least one of the light emitting element and the light receiving element. Can reliably block light.
[0014]
The invention according to claim 7 is a water heater for boiling water and keeping the temperature warm, a liquid level tube provided on a side surface of the water heater container to indicate a liquid level of the water heater container, and a liquid level tube provided inside the liquid level tube. A float that can move up and down according to, a liquid level detecting means including a light emitting element and a light receiving element provided opposite to the side surface of the liquid level tube, and a condenser lens on the front surface of the light emitting element, Since the focal point of the condenser lens is located between the center of the liquid level tube and the light receiving element, the light emitted from the light emitting element passes through the center of the liquid level tube, so that the light generated by the float is The interruption can be ensured.
[0015]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings, with reference to the drawings, illustrating a two-container type electric water heater having two containers, a water heater container and a water supply container, in which the effects of the present invention are remarkably exhibited.
[0016]
FIG. 1 is a sectional view of a main part of a liquid level detecting means of an electric water heater in an embodiment of the present invention, and FIG. 2 is a sectional view of the electric water heater.
[0017]
In FIG. 2, reference numeral 11 denotes a water heater for boiling the stored water to keep it warm, 12 means a heating means comprising a main heater for heating the water heater 11 and a heat keeping heater for keeping the temperature, and 13 means a hot water for the water in the water heater 11. A tapping means 16 which is a pump for discharging from the tap hole 15 via the level pipe 14 is a float provided in the level pipe 14 and movable up and down in accordance with the level fluctuation of the level.
[0018]
In addition, the relationship between the liquid level tube 14 and the float 16 is such that if the outer shape of the float 16 is too large with respect to the inner diameter of the liquid level tube 14, it is difficult to discharge hot water at the time of tapping, and conversely, the size of the float 16 is small. If it is too small, the light blocking performance, which will be described later, deteriorates, and it becomes difficult to detect the water level. Therefore, the relationship between the inner diameter of the liquid level tube 14 and the float 16 is determined by design in consideration of these matters. Normally, in an electric water heater having a capacity of about 2 liters, the inner diameter between liquid levels is 10 mm, and the outer shape of a ball used as a float is about 5.8 mm.
[0019]
Reference numeral 17 denotes a water amount detecting means, which comprises a light emitting element 18 and a light receiving element 19 which are attached to face the liquid level tube 14. Then, by detecting the liquid level of the liquid level tube 14 at which the liquid level becomes the same as that of the water heater vessel 11, the water level of the water heater vessel 11 is detected. 17a is a full water detection installed at the full water position, and 17b is a water supply detection. When the water level falls below this position, water is automatically supplied. Numeral 17c denotes an idling prevention detection. If the water level falls below this position, there is a danger of idling, so that the heating means 12 is stopped to prevent idling. Reference numeral 20 denotes a light-shielding plate which is a light-shielding means having a gap 21 for transmitting light, which is a feature of the present embodiment, and is provided on the front surface of the light-emitting element 18 and the light-receiving element 19. Therefore, only the light that has passed through the gap 21 of the light-shielding plate 20 out of the light from the light-emitting element 18 is radiated to the liquid level tube side, so that the light is hardly diffused and has strong directivity. Further, by providing the light shielding plate 20 on the front surface of the light receiving element 19, almost straight light is transmitted through the gap 21 and reaches the light receiving element 19, so that diffused light is hardly reached.
[0020]
Reference numeral 22 denotes a water supply container for storing water for supplying water to the water heater container, and reference numeral 23 denotes a water supply means for supplying water from the water supply container 22 to the water heater container 11 via a water supply pipe 24. 25 is a temperature detecting means for detecting the temperature of the hot water in the water heater container 11, 26 is a hot water switch for operating the user to instruct hot water, and 27 is a lock release switch for permitting reception of the hot water switch 26. Reference numeral 28 denotes a water stop valve for preventing the internal hot water from spilling when the electric water heater falls down, and opens and closes in conjunction with the operation of the hot water switch 26.
[0021]
The operation of the electric water heater configured as described above will be described below.
[0022]
The case where water is supplied from an empty state of the water heater container 11 will be described. When the power is turned on to the electric water heater, a control unit (not shown) receives a signal indicating that the detected water amount of the water amount detecting means is equal to or less than the empty-fire prevention detection 17c, and activates the water supplying means 23 to start water supply. Then, when the water level becomes equal to or higher than the empty-fire prevention detection level 17c, which is the empty-fire prevention water level, the heating unit 12 is turned on to start heating.
[0023]
Further, when the water supply is continued and the water level rises and reaches the full water detection 17a, the water supply means 23 is stopped to terminate the water supply. Thereafter, the supplied water is heated by the main heater or the main heater and the heat retaining heater until the temperature is detected by the temperature detecting means 25, and is kept warm by the heat retaining heater after the detection of the boiling. From this state, the hot water in the kettle 11 is appropriately used, and the water level thereof decreases. When the water is dropped and the water level falls below the water supply detection 17b, the water supply is started after a lapse of a predetermined time after the completion of the water supply. This makes it possible to always secure a certain amount or more of hot water. In this way, automatic water supply and tapping are repeatedly used.
[0024]
In this embodiment, the detection by the liquid level detecting means 17 is performed at three places: a full water detection 17a, a water supply detection 17b, and an empty heating prevention detection 17c. The full water detection 17a is a maximum water volume determined by design, and is a water level at which if water is supplied more than this, there is a danger such as hot water spillage when boiling. As described above, the water supply detection 17b is a water level at which water is supplied and the water supply is started after a predetermined time has elapsed after the end of the water supply and the water level falls below the water supply detection 17b. Hot water having a capacity equal to or larger than the capacity can be secured.
[0025]
Further, the empty-fire prevention detection 17c is a water level at which a danger of empty-fire occurs when the water level falls below this level. Therefore, when the water level falls below this empty-fire prevention detection 17c, the heating means 12 is shut off so that no empty-fire occurs. I have to.
[0026]
As described above, the full water detection 17a and the empty heating prevention detection 17c are detections necessary for safety, and the water supply detection 17b is detection necessary for improving convenience. Therefore, the detection accuracy needs to be high.
[0027]
Hereinafter, the configuration of the present embodiment for improving the detection accuracy of the liquid level detecting means will be described with reference to FIG. In FIG. 1, the light emitting element 18 and the light receiving element 19 are provided so as to face each other substantially on the center line of the liquid level tube 14. Further, shielding plates 20 as light shielding means are provided between the liquid level tube 14 and the light emitting element 18 and between the liquid level tube 14 and the light receiving element 19, respectively. A gap 21 is provided in the shielding plate 20, and the gap 21 of each light shielding plate 20 is arranged on a line connecting the light emitting element 18 and the light receiving element 19. Therefore, the light emitted from the light emitting element 18 normally has a light distribution angle and diffuses around, but most of the light is blocked by the shielding plate 20 and only the light L passing through the gap 21 has strong directivity. To the liquid level tube 14.
[0028]
If the float 16 is not present in the liquid level tube 14 at this time, the light passes through the liquid level tube 14 and passes through the gap 21 of the shielding plate 20 provided between the light receiving element 19 and the liquid level tube 14 to receive light. The element 19 is reached. At this time, the light shielding plate 20 provided on the front surface of the light receiving element 19 prevents diffused light from the surroundings from entering the light receiving element 19. This indicates that there is no water level at the position of the liquid level detecting means 17, that is, it is either filled with liquid or there is no liquid.
[0029]
If the level tube 14 has a float 16, as shown in FIG. 1, for example, the inner diameter of the level tube 14 is 10 mm, the outer shape of the ball used as the float 16 is 5.8 mm, and However, since the optical path passes through the center of the liquid level tube 14 even if it is deviated to one side, the light is always blocked by the float 16 and does not reach the light receiving element 19. Thereby, it is understood that the water level is at the position of the liquid level detecting means 17.
[0030]
As described above, in the present embodiment, light is emitted and received through the gap 21 provided in the shielding plate 20, so that detection can be performed accurately without being affected by the surroundings such as light scattering and refraction. .
[0031]
In the above description, the example in which the light shielding plate 20 is provided before the light emitting element 18 and the light receiving element 19 has been described. However, when the light emission of the light emitting element 18 is sufficiently strong, that is, it can be distinguished from other light. In this case, there is no problem even if only one of them is provided. In addition, as long as the gist of the present embodiment is satisfied, the position where the light emitting element 18 and the light receiving element 19 face each other, the shape of the gap, and the like are not particularly limited to the above-described configuration. Needless to say, the respective light shielding plates 20 and gaps 21 provided before the element 19 do not have to have the same configuration. The gap 21 may be formed of a light-transmitting film instead of a space.
[0032]
As described above, in this embodiment, the water level can be accurately detected based on whether or not the float 16 blocks light. Therefore, if the float is always stopped at the positions of the full water detection and the empty heating prevention detection, the full water position and the water supply position can be reliably detected, so that safety can be secured. In addition, after a water supply detection is provided at a predetermined position and water is checked for the first time, water is supplied when light is first blocked, thereby enabling automatic water supply and improving convenience.
[0033]
In addition, in order to detect whether or not the liquid level has reached the threshold for performing automatic water supply, the light-emitting element and the light-receiving element are additionally provided at one place between the full water position and the water supply position, but are limited to one place. For example, the liquid level in the heating vessel can be accurately detected by providing the liquid level in a plurality of places, and the liquid level can be displayed on a display means such as a liquid crystal display element based on the detected liquid level. In addition, based on the detected liquid level, by changing the heating and keeping control by the heating means, it is possible to improve the detection accuracy at the time of boiling and prevent the steam from continuing to be emitted during the boiling. is there.
[0034]
Further, the case where a plate-like body is used as the light shielding means has been described, but the invention is not limited to this. As shown in FIG. 3, a light shielding film 29 such as printing or painting is directly provided on the liquid level tube 14 as the light shielding means. The light shielding film 29 may be provided with a gap 29a. Of course, either one of the light shielding means may be used as necessary.
[0035]
Further, as shown in FIG. 4, the light shielding means may be constituted by a light shielding body 30 that covers at least the periphery of the liquid level tube 14, and the light shielding body 30 may be provided with a gap 30a. Further, either one of the light shields 30 may be used as necessary. When a decorative plate is attached to the liquid level tube 14, the decorative plate may be used as a light shielding plate.
[0036]
Further, as a light-shielding means, a coating film or a cap may be provided directly on the light-emitting portion 31 of the light-emitting element 18 to form the light-shielding layer 32. FIG. 5 shows a case where a cap is covered as a light shielding layer 32, and a gap 33 through which light passes is provided in a part thereof. Similarly, the directivity may be enhanced by allowing light to enter only a part of the light receiving element 19. When the light-emitting portion 31 is covered with a cap as a light-shielding layer, it is preferable to provide a space 33 between the light-emitting portion 31 and the gap 32a between the cap because the directivity of light is increased.
[0037]
Although the case where the light shielding means is used has been described above, in addition to such a method, a condensing lens 34 is provided on the front surface of the light emitting element 18 as shown in FIG. Light may be collected at a position. Thereby, diffusion of light can be prevented, and most of the light can be prevented from leaking to the surroundings through the center of the liquid level tube 14, so that the light can be reliably blocked by the float 16 and the detection accuracy can be improved. Can be increased. The condenser lens may be provided so that the liquid level tube and the lens are integrated. In addition, the focus of the condenser lens 34 is not limited to the position of the light receiving element 19, and an effect can be obtained by adopting a configuration in which the focus is easily blocked by the float 16. For example, even if the focus is set to the center of the liquid level tube 14, Needless to say, the effect can also be obtained by setting the position between the center of the liquid level tube 14 and the light receiving element 19.
[0038]
As described above, by using the light shielding means, it is possible to accurately determine whether or not the liquid level has reached a predetermined position, and to improve safety and convenience.
[0039]
In the description of this embodiment, an electric water heater having two containers, a water heater container and a water supply container, has been described. However, the present invention is not limited to this, and the configuration of the present invention may be applied to an electric water heater having only a water heater container. Similar effects can be obtained. However, in this case, water supply detection is generally unnecessary.
[0040]
Further, in the description of the present embodiment, the float is illustrated as a sphere, but the float is not limited to a sphere, and any shape may be used as long as there is no obstacle to the light blocking performance and the condition of hot water at the time of tapping. The effect of is obtained.
[0041]
【The invention's effect】
As described above, according to the first to seventh aspects of the present invention, an electric water heater that accurately determines whether or not a liquid level has reached a predetermined position and improves safety and convenience is provided. Can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a liquid level detecting means of an electric water heater according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the electric water heater. FIG. 3 is a cross-sectional view of a main part of a liquid level detecting means of the electric water heater. FIG. 4 is a cross-sectional view of a main part of a liquid level detecting means of the electric water heater. FIG. 5 is a partial cross-sectional view of a main part of a light emitting element used for a liquid level detecting means of the electric water heater. FIG. 6 is a liquid level detecting means of the electric water heater. FIG. 7 is a cross-sectional view of a main part of a conventional electric water heater. FIG. 8 is a cross-sectional view of a main part of a liquid level detecting means of the electric water heater.
11 water heater 14 liquid level tube 16 float 17 liquid level detecting means 18 light emitting element 19 light receiving element 20 light shielding plate (light shielding means)
21, 29a, 30a, 32a Gap 29 Light shielding film (light shielding means)
30 Shading body (shading means)
32 Light shielding layer (light shielding means)
35 Condensing lens

Claims

A water kettle for boiling water to keep warm, a liquid level tube provided on a side surface of the water heater container and indicating a liquid level of the water kettle, and a float provided inside the liquid level tube and movable up and down according to the liquid level; A liquid level detecting means comprising a light emitting element and a light receiving element provided opposite to a side surface of the liquid level tube; and a light shielding means provided on a front surface of the light emitting element and the light receiving element. An electric water heater having a gap through which the water passes.

2. The electric water heater according to claim 1, wherein the light shielding means has a plate state.

The electric water heater according to claim 1, wherein the light shielding means is provided in the liquid level tube.

2. The electric water heater according to claim 1, wherein the light-shielding means comprises a light-shielding body that covers at least a periphery of the liquid level detection unit.

2. The electric water heater according to claim 1, wherein the light shielding means and a decorative plate for decorating the liquid level tube are integrated.

2. The electric water heater according to claim 1, wherein the light shielding means is provided on at least one of the light emitting element and the light receiving element.

A water kettle for boiling water to keep warm, a liquid level tube provided on a side surface of the water heater container and indicating a liquid level of the water kettle, and a float provided inside the liquid level tube and movable up and down according to the liquid level; A liquid level detecting means comprising a light emitting element and a light receiving element provided opposite to a side surface of the liquid level tube, and a condenser lens on the front surface of the light emitting element, wherein the focal point of the condenser lens is An electric water heater configured to be located between the center of the position tube and the light receiving element.