JP4604272B2 - Gas burning appliances - Google Patents

Description

尚、表中のＯは正常燃焼を示し、×は異常燃焼を示す。この異常燃焼には、着火に失敗してバーナに火炎が形成されない場合も含まれる。
【００２２】
上述のように構成された給湯器では、図示しない給湯栓を開くことにより給水管１４に水が流れると、水側制御ユニット５１内の水流センサからの検知信号によりコントローラ５０は、ファン６０を駆動してプリパージを開始すると共に、図２のフローチャートに示されるように、ガス種判別制御を開始する。
先ず、ＬＰＧ仕様に設定し、つまりＬＰＧに適した空燃比制御データを選択し（Ｓ１）、イグナイタをオンする（Ｓ２）と共に、比例弁３１を点火用の所定開度に設定し、元開閉弁３２を開弁して（Ｓ３）、メインバーナ１１とセンサーバーナ１２とへ燃料ガスを供給し点火し、イグナイタをオフする（Ｓ４）。
【００２３】
そして、第２フレームロッド４２がセンサーバーナ１２の炎電流を検知し、その電流値Ｉｊが着火レベル未満であるか否か判断する（Ｓ５）。
検知電流値Ｉｊが着火レベル未満であれば、着火異常と判断する（Ｓ６）。この検知電流値Ｉｊが着火レベル未満になる要因としては、比例弁３１の故障により燃料ガスが十分供給されずインプットが所望のレベルより少なかったり、元開閉弁３２の故障により燃料ガスが供給されなかったり、ファン６０の故障により理論空気量に対する実際の空気量を示す一次空気比が大き過ぎたり、イグナイタが正常にオンしていないこと等が考えられる。
そして、比例弁３１，元開閉弁３２を閉弁して（Ｓ７）、メインバーナ１１とセンサーバーナ１２とを消火する。
一方、検知電流値Ｉｊが着火レベル以上であれば、着火異常はないとしてステップ８へ進む。
【００２４】
ステップ８において、第１フレームロッド４１がメインバーナ１１の炎電流を検知し、その電流値Ｉｍが判定値以上であれば、メインバーナ１１が正常燃焼しているとして、供給ガスがＬＰＧであると判断し、その燃焼仕様のまま燃焼を継続する（Ｓ９）。
【００２５】
一方、検出電流値Ｉｍが判定値未満であれば、メインバーナ１１が着火していない（或いは異常燃焼している）として、供給ガスがＤＭＥであると判断し（Ｓ１０）、比例弁３１，元開閉弁３２を閉弁して（Ｓ１１）、メインバーナ１１とセンサーバーナ１２とを消火する。
【００２６】
そして、ＤＭＥ仕様に設定し、つまり、ＬＰＧが供給される場合と同じインプットになるようにガス流量をＬＰＧの場合よりも増やすと共に、適正な空燃比で燃焼するようにファン６０の回転数を制御するようなＤＭＥ用の空燃比制御データを選択し（Ｓ１２）、ステップ２へ戻って、メインバーナ１１とセンサーバーナ１２とを点火し（Ｓ３，Ｓ４）、着火異常が無ければ（Ｓ５）、ステップ８へ進む。
この時、ＤＭＥ仕様に設定されているため、メインバーナ１１は、正常燃焼し、ステップ８では、検知電流値Ｉｍが判定値以上となって、そのＤＭＥ仕様のまま燃焼を継続する（Ｓ９）。
【００２７】
このようにしてガス種を判別した後、図示しないリモコンで設定された出湯温度と入水温サーミスタ５２で検出された入水温度との温度差に入水流量を乗じて要求インプットＩｐを算出し、供給ガス種に対応した空燃比制御データに基づいてフィードフォーワード燃焼制御を開始する。この燃焼制御中に、出湯温サーミスタ５３で検出される湯温と設定温度とに温度差があると、熱交換器１３の出口温度を一定に保たせるように比例弁電流Ｉを連続的に補正すると共に、常にガス量と給気量とが所定の関係に保たれるようにファン６０の回転数も補正するフィードバック燃焼制御を行う。
【００２８】
つまり、ガス種が変更されたことを判定した場合には、自動的にその変更後のガス種に適した空燃比制御データに切り替えてフィードフォワード燃焼制御およびフィードバック燃焼制御を行う。
そして、図示しない給湯栓が閉められると、比例弁３１，元開閉弁３２を閉弁して、各バーナ１１，１２へのガス供給を遮断して消火する。
【００２９】
以上説明したように、本実施形態の給湯器では、メインバーナ１１の燃焼状態とセンサーバーナ１２の燃焼状態とから、ガス種を正確に判別する。
例えば、センサーバーナを備えずにメインバーナ１１の燃焼状態だけでガス種を判別する場合には、メインバーナ１１が異常燃焼する際に、燃焼仕様と異なるガス種のＤＭＥが供給されたためなのか、それとも着火異常のためなのか区別できない。従って、着火異常でもＤＭＥが供給されていると誤判別してしまう。
これに対して、本実施形態では、２つのバーナの燃焼状態を示す信号の組み合わせに応じて正しくガス種の判別を行うことができる。
ガス種を切り替えてもインプットを等しくすることができ、給湯器の燃焼や出力などの特性を良好に維持できる。
【００３０】
このようにして、ＬＰＧとＤＭＥとをその市場価格，供給状況に応じて適宜切り替えて使うといった並行使用が可能になり、経済的である。この際、使用者は燃料ガスを区別して器具を使用しなくてもよく、安全で使い勝手がよい。
また、自動的にガス種に適した燃焼仕様に切り替えるため、ガス種転換作業が不要となり便利である。
【００３１】
また、本実施形態の給湯器は強制燃焼式であるため、燃焼仕様が異なると、メインバーナ１１の火炎がリフトしたり、火炎自体が形成されないことが多々あるが、ステップ１１で一旦比例弁３１，元開閉弁３２を閉弁して消火するため、生ガスの漏出を防止でき安全である。
【００３２】
しかも、バーナの燃焼状態を検知する火炎検知素子としてフレームロッドを用いたため、立ち上がりが早くしかも応答性が良いため、ＤＭＥが供給されても、ガス種判別中におけるメインバーナ１１の異常燃焼（或いは不着火）時間が短く、安全である。
【００３３】
また、点火操作時にステップ１でＬＰＧ仕様に設定しているため、ＤＭＥ仕様に初期設定する場合よりも、使用するガス流量が少なくインプット過多を防止でき安全である。
つまり、ＤＭＥ仕様に初期設定する場合においては、ＤＭＥが低ＷＩガスであるため、供給ガス流量がＬＰＧ仕様よりも多く、ＬＰＧが供給されると、インプット過多になってしまう。これに対して本実施形態では、ステップ１でＬＰＧ仕様に設定しているため、インプット過多を防止できて安全である。
【００３４】
《第２実施形態》
次に、第２実施形態について図３のフローチャートを用いて説明する。尚、第１実施形態と異なる部分について説明し、重複する部分に関しては同一ステップ番号を付してその説明を省略する。
【００３５】
強制燃焼式ガス給湯器に、燃料ガスのＷＩの異なるＤＭＥやＬＰＧを正常燃焼する（火炎を形成する）メインバーナと、特定の燃料ガス（ここではＬＰＧ）が供給される場合にのみ正常燃焼するセンサーバーナとを設ける。尚、このメインバーナは、炎口形状や炎口負荷を調整したり、保炎用の炎口を設けたりすることで、ＤＭＥでもＬＰＧでも火炎を形成することができる。
この場合の各バーナの燃焼状態と判定結果の関係を表２に示す。
【００３６】
【表２】

【００３７】
上述のバーナを備えた給湯器では、第１実施形態と同様に、ガス種判別制御を開始し、各バーナを点火する（Ｓ１〜Ｓ４）。
そして、メインバーナの炎電流値Ｉｍが着火レベル未満であるか否か判断する（Ｓ１３）。
検知電流値Ｉｍが着火レベル未満であれば、着火異常と判断し（Ｓ６）、比例弁３１，元開閉弁３２を閉弁して（Ｓ７）、メインバーナとセンサーバーナとを消火する。
一方、検知電流値Ｉｍが着火レベル以上であれば、着火異常はないとしてステップ１４へ進む。
【００３８】
ステップ１４において、センサーバーナの炎電流値Ｉｊが判定値以上であれば、センサーバーナが正常燃焼しているとして、供給ガスがＬＰＧであると判断し、その燃焼仕様のまま燃焼を継続する（Ｓ９）。
【００３９】
一方、ステップ１４において、検出電流値Ｉｊが判定値未満であれば、供給ガスがＤＭＥであると判断し（Ｓ１０）、ステップ１５に進み、この段階ではＬＰＧ仕様に設定されているため、ステップ１１に進んで比例弁３１，元開閉弁３２を閉弁して、各バーナを消火し、ＤＭＥ仕様に設定し（Ｓ１２）、ステップ２〜１０まで行う。この段階では、ＤＭＥ仕様に設定されているためステップ１５からステップ９へ進み、その燃焼仕様のまま燃焼を継続する。
【００４０】
以上説明した給湯器は、第１実施形態と同様の効果が得られ、判別したガス種の燃焼仕様に自動的かつ安全に切り替えることができる。
また、センサーバーナでは、ガス種による燃焼状態の差を大きく取れるように設計して製造できるため、メインバーナの燃焼状態を示す信号との組み合わせにより、正確にガス種を判別することができる。
【００４１】
以上本発明の実施形態について説明したが、本発明はこうした実施形態に何等限定されるものではなく、本発明の要旨を逸脱しない範囲において、種々なる態様で実施し得ることは勿論である。
例えば、フレームロッドに代えて熱電対を用い、その起電力を検知してガス種を判別してもよい。
また、ガス種を判定して適正な燃焼仕様に設定した後は、センサーバーナを消火してもよい。
【００４２】
また、ステップ１においてＤＭＥ仕様に設定してもよい。
この場合、第１実施形態では、表３に示されるように、メインバーナ１１とセンサーバーナ１２の両方が正常燃焼すると供給ガスがＤＭＥであると判断して燃焼を継続し、センサーバーナ１２のみ正常燃焼するとＬＰＧであると判断して燃焼仕様をＬＰＧ用に変更する。
【００４３】
【表３】

【００４４】
一方、第２実施形態では、表４に示されるように、メインバーナとセンサーバーナの両方が正常燃焼すると供給ガスがＤＭＥであると判断して燃焼を継続し、メインバーナのみ正常燃焼するとＬＰＧであると判断して燃焼仕様をＬＰＧ用に変更する。
【００４５】
【表４】

【００４６】
また、ステップ１においてガス種の燃焼仕様をＬＰＧとＤＭＥとの何れか一方に常に固定するのではなく、正常に燃焼されたガス種の燃焼仕様を設定し記憶させておいて、次回からもその設定仕様でガス種判別制御を開始してもよい。この場合、供給ガス種が直前回と同じであれば、ガス種判別制御時間が短縮される。
【００４７】
また、自動で燃焼仕様を切り替えずに、ガス種判定後、その判定結果を報知する報知手段を設けて、この報知を受けた作業者が手動で燃焼仕様を切り替えるようにしてもよい。この報知手段として、アラームや音声メッセージといった聴覚情報や、ランプやディスプレイといった視覚情報を用いて報知するものを用いてもよい。
【００４８】
また、強制燃焼式のガス器具ではなく、テーブルこんろといった自然燃焼式のガス器具に本発明を適用してもよい。自然燃焼式の場合は、供給ガスが設定仕様と異なっても火炎を形成しやすいので、特に、第２実施形態において、こうした特性を持つメインバーナの設計が容易となる。
また、自然燃焼式のガス器具等、供給ガスが設定仕様と異なっても火炎を形成できる場合には、ガス種判定後、ガス供給路を閉鎖せずに、そのまま燃焼仕様を切り替えて燃焼を継続してもよい。
【００４９】
【発明の効果】
以上詳述したように、本発明の請求項１のガス燃焼器具によれば、メインバーナとセンサーバーナの燃焼状態に応じてガス種を判別するため、メインバーナの異常燃焼がガス種違いによるものなのか、着火異常によるものなのかを判断でき、正確にガス種を判別できる。
この結果、判別された燃料ガスに適した燃焼仕様に切り替えることにより、２種類の燃料ガスを並行使用することができる。
【００５０】
更に、本発明の請求項２のガス燃焼器具によれば、メインバーナとセンサーバーナの燃焼状態に応じてガス種を判別するため、センサーバーナの異常燃焼がガス種違いによるものなのか、着火異常によるものなのかを判断でき、正確にガス種を判別できる。
この結果、判別された燃料ガスに適した燃焼仕様に切り替えることにより、２種類の燃料ガスを並行使用することができる。
また、メインバーナではなくセンサーバーナでガス種を判別するため、ガス種による燃焼状態の差を大きく取ることができ、正確にガス種を判別することができる。
【００５１】
更に、本発明の請求項３のガス燃焼器具によれば、着火異常時には、両方のバーナを消火するため、生ガスの漏出を防ぐことができ、安全である。
【００５２】
更に、本発明の請求項４のガス燃焼器具によれば、ガス種を切り替えてもインプットが等しくなり、燃焼器具の燃焼や出力などの特性が悪化することがない。
また、燃焼仕様が自動的に切り替わりガス種転換作業が不要となる。
【００５３】
更に、本発明の請求項５のガス燃焼器具によれば、ガスボンベという同じガス供給形態のＬＰＧとＤＭＥとを判別でき切り替えて使用できるため、市場価格，供給状況等に応じて燃料ガスを選択でき、経済的である。
【図面の簡単な説明】
【図１】第１実施形態としてのガス燃焼器具の概略構成図である。
【図２】第１実施形態としての着火シーケンスを示すフローチャートある。
【図３】第２実施形態としての着火シーケンスを示すフローチャートある。
【符号の説明】
１１…メインバーナ、１２…センサーバーナ、３１…比例弁、３２…元開閉弁、４１…第１フレームロッド、４２…第２フレームロッド、５０…コントローラ、６０…ファン。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas burning device capable of burning fuel gases having different Wobbe indices.
[0002]
[Prior art]
Currently, city gas and LP gas (liquefied petroleum gas mainly composed of propane, hereinafter referred to as LPG) are known as gas species to be supplied to household gas combustion appliances. Slightly expensive. Therefore, recently, the use of inexpensive dimethyl ether (hereinafter referred to as DME) as an alternative fuel for LPG has been studied.
In addition, since the supply of DME is not sufficient at present, there is no guarantee that DME can always be used, and when the supply of DME is stagnant, it is necessary to use LPG, and LPG will be transferred to DME in the future. Even if it replaces, it is also considered to use DME and LPG in parallel for the time being.
[0003]
[Problems to be solved by the invention]
However, since the Wobbe index (hereinafter referred to as WI) is significantly different between DME and LPG, if DME is supplied as it is to the combustion equipment for LPG, the calorific value (input) per unit time will change significantly and combustion will occur. Since the characteristics such as the combustion and output of the instrument are deteriorated, it is necessary to determine whether the supply gas is DME or LPG and adjust the gas supply flow rate or the combustion air supply flow rate suitable for the gas type.
Then, the gas combustion instrument of this invention aims at solving the said subject and providing the gas combustion instrument which discriminate | determines the kind of fuel gas.
[0004]
[Means for Solving the Problems]
The gas combustion appliance according to claim 1 of the present invention for solving the above-mentioned problems is
Gas combustion for storing combustion specifications such as supply gas flow rate for two types of fuel gases having different Wobbe indices (WI) and controlling combustion in accordance with the combustion specifications of any one of the preset fuel gases In the instrument,
A main burner that normally burns when the set type of fuel gas is supplied, and abnormally burns when the other fuel gas is supplied;
A sensor burner that burns normally regardless of which of the two types of fuel gas is supplied,
A first flame detection element for detecting a flame state of the main burner;
A second flame detecting element for detecting a flame state of the sensor burner;
It is provided with a gas type discriminating means for discriminating the type of the supplied fuel gas according to the combination of the detection signal from the first flame detection element and the detection signal from the second flame detection element. To do.
[0005]
Moreover, the gas combustion appliance according to claim 2 of the present invention is
Gas combustion for storing combustion specifications such as supply gas flow rate for two types of fuel gases having different Wobbe indices (WI) and controlling combustion in accordance with the combustion specifications of any one of the preset fuel gases In the instrument,
A main burner that forms a predetermined flame regardless of which of the two types of fuel gas is supplied;
A sensor burner that normally burns when the set type of fuel gas is supplied, and abnormally burns when the other fuel gas is supplied;
A first flame detection element for detecting a flame state of the sensor burner;
A second flame detection element for detecting a flame state of the main burner;
It is provided with a gas type discriminating means for discriminating the type of the supplied fuel gas according to the combination of the detection signal from the first flame detection element and the detection signal from the second flame detection element. To do.
[0006]
Moreover, the gas combustion appliance according to claim 3 of the present invention is the gas combustion appliance according to claim 1 or 2,
When an abnormal signal is output from the second flame detection element, the gist is to extinguish all the burners.
[0007]
Moreover, the gas combustion appliance according to claim 4 of the present invention is the gas combustion appliance according to any one of claims 1 to 3,
Automatic specification setting means for automatically setting the combustion specification of the main burner according to the determination result of the gas type determination means,
The gist is to burn with the same calorific value per unit time regardless of the WI of the fuel gas.
[0008]
Moreover, the gas combustion appliance according to claim 5 of the present invention is the gas combustion appliance according to any one of claims 1 to 4,
The gist of the fuel gas is that the low WI gas is dimethyl ether and the high WI gas is LP gas.
[0009]
The gas combustion appliance according to claim 1 of the present invention having the above-mentioned configuration is in a state where it is set to a combustion specification corresponding to one gas type (for example, high WI gas) of two types of fuel gas, and its type. When the fuel gas (here, high WI gas) is supplied, both the main burner and the sensor burner normally burn, and both the first flame detection element and the second flame detection element output normal signals. From this combination of detection signals, it is determined that the same type of gas as the set specification (here, high WI gas) has been supplied.
On the other hand, when a fuel gas of a different type from the set specification (here, low WI gas) is supplied, the main burner burns abnormally and the first flame detection element outputs an abnormal signal. At this time, there are two possible ways: a gas different from the combustion specification (here, a low WI gas) is supplied and there is an abnormality in the gas combustion appliance.
Therefore, it can be determined by referring to the output signal from the second flame detection element. That is, when the sensor burner is normally combusted and the second flame detection element outputs a normal signal, it is determined that a gas different from the set specification (here, low WI gas) is supplied. On the other hand, when a normal signal cannot be obtained from the second flame detection element, it is determined that an ignition abnormality has occurred.
In this manner, the type of the supply gas is accurately determined according to the combination of detection signals output from the first flame detection element and the second flame detection element.
In addition, abnormal combustion represents the state which is not burning normally, and also includes the state which has misfired.
[0010]
In addition, the gas combustion appliance according to claim 2 of the present invention is a type of fuel that is set to a combustion specification corresponding to one of the two types of fuel gas (for example, high WI gas). When gas (here, high WI gas) is supplied, both the sensor burner and the main burner normally burn, and both the first flame detection element and the second flame detection element output normal signals. From this combination of detection signals, it is determined that the same type of gas as the set specification (here, high WI gas) has been supplied.
On the other hand, when a fuel gas of a type different from the set specification (here, low WI gas) is supplied, the sensor burner burns abnormally and the first flame detection element outputs an abnormal signal. At this time, whether the cause of abnormal combustion of the sensor burner is that a gas different from the combustion specification (here, low WI gas) is supplied, or whether the gas combustion appliance is abnormal is the first flame. It cannot be distinguished from the output signal of the sensing element.
Therefore, it can be distinguished by combining the output signal from the second flame detection element that detects the flame state of the main burner and the output signal from the first flame detection element.
That is, when the main burner burns normally and the second flame detection element outputs a normal signal, it is determined that a gas (here, low WI gas) different from the set specification has been supplied. On the other hand, when a normal signal cannot be obtained from the second flame detection element, it is determined that an ignition abnormality has occurred.
In this manner, the type of the supply gas is accurately determined according to the combination of detection signals output from the first flame detection element and the second flame detection element.
[0011]
Moreover, the gas combustion appliance according to claim 3 of the present invention extinguishes the main burner and the sensor burner when an abnormal signal is output from the second flame detection element.
[0012]
Further, the gas combustion appliance according to claim 4 of the present invention automatically sets the combustion specifications of the main burner according to the determination result of the gas type determination means, so that the unit per unit time is the same regardless of the WI of the fuel gas. The main burner is burned with the heat generated (input).
[0013]
Further, the gas combustion appliance according to claim 5 of the present invention increases the gas flow rate and the air passage resistance when DME is supplied, compared with the case of LPG, and burns the burner normally with the same input as LPG. Let
Since DME can be supplied in a gas cylinder in the same manner as LPG, it can be safely used as an alternative fuel for LPG.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In order to further clarify the configuration and operation of the present invention described above, preferred embodiments of the gas combustion appliance of the present invention will be described below.
<< First Embodiment >>
A water heater as a first embodiment of the present invention will be described with reference to FIGS.
[0015]
The water heater 10 includes a main burner 11 that normally burns when combustion control is performed based on air-fuel ratio control data (described later) suitable for the type of fuel gas, and DME (low WI gas) or LPG having a different WI of fuel gas. A sensor burner 12 that normally burns (high WI gas), a fan 60 that forcibly supplies primary air for combustion to each burner 11, 12, and a fin tube type that heats water by the combustion heat of the main burner 11 A heat exchanger 13. The sensor burner 12 can form a flame with either DME or LPG by adjusting the shape of the flame mouth and the load of the flame mouth, or by providing a flame mouth for flame holding, but less than the ignition input. It cannot burn normally at the input.
[0016]
The water pipe provided in the water heater 10 includes a water supply pipe 14, a heat transfer pipe 13 a provided in the heat exchanger 13, and a hot water pipe 15 in order from the upstream. The water supply pipe 14 is provided with a water-side control unit 51 including a water flow sensor and a water governor, and an incoming water temperature thermistor 52, and the hot water outlet pipe 15 is provided with a hot water temperature thermistor 53.
[0017]
A first gas pipe 21 serving as a gas flow path for supplying fuel gas to the main burner 11 includes a main open / close valve 32 for opening and closing the gas flow path in order from the upstream, and a proportional valve capable of adjusting the gas flow rate to the main burner 11. 31 is provided, and a second gas pipe 22 that is a gas flow path that branches from between the main opening / closing valve 32 and the proportional valve 31 and supplies fuel gas to the sensor burner 12 is provided.
[0018]
A first frame rod 41 for detecting the flame current of the main burner 11 is provided in the vicinity of the main burner 11, while a second frame for detecting the flame current of the sensor burner 12 is provided in the vicinity of the sensor burner 12. A rod 42 is provided. An igniter (not shown) for igniting both burners 11 and 12 is also provided.
[0019]
The proportional valve 31, the original opening / closing valve 32, the frame rods 41 and 42, the igniter, and the fan 60 are electrically connected to a controller 50 that performs combustion control of the burners 11 and 12.
[0020]
The controller 50 selects air-fuel ratio control data corresponding to a gas type determined by a method described later. This air-fuel ratio control data represents the target control value of the gas proportional valve current with respect to the required input Ip and the rotational speed of the fan 60 for each gas type, and is stored in the nonvolatile memory.
That is, the flow rate of the gas supplied to the main burner 11 is adjusted by controlling the opening degree of the proportional valve 31, and the air flow rate supplied to the main burner 11 is adjusted by controlling the rotational speed of the fan 60.
[0021]
Here, Table 1 shows the relationship between the gas type discrimination and the combustion states of the burners 11 and 12.
[Table 1]

In the table, O indicates normal combustion, and x indicates abnormal combustion. This abnormal combustion includes a case where ignition fails and no flame is formed in the burner.
[0022]
In the water heater configured as described above, when water flows into the water supply pipe 14 by opening a hot water tap (not shown), the controller 50 drives the fan 60 by a detection signal from the water flow sensor in the water side control unit 51. Then, the pre-purge is started, and the gas type discrimination control is started as shown in the flowchart of FIG.
First, the LPG specification is set, that is, air-fuel ratio control data suitable for the LPG is selected (S1), the igniter is turned on (S2), the proportional valve 31 is set to a predetermined opening for ignition, and the original on-off valve 32 is opened (S3), fuel gas is supplied to the main burner 11 and the sensor burner 12 and ignited, and the igniter is turned off (S4).
[0023]
Then, the second frame rod 42 detects the flame current of the sensor burner 12, and determines whether or not the current value Ij is less than the ignition level (S5).
If the detected current value Ij is less than the ignition level, it is determined that the ignition is abnormal (S6). Factors that cause the detected current value Ij to be less than the ignition level are that fuel gas is not sufficiently supplied due to a failure of the proportional valve 31 and the input is less than a desired level, or fuel gas is not supplied due to a failure of the original opening / closing valve 32. The primary air ratio indicating the actual air amount with respect to the theoretical air amount may be too large due to a failure of the fan 60, or the igniter may not be normally turned on.
Then, the proportional valve 31 and the original opening / closing valve 32 are closed (S7), and the main burner 11 and the sensor burner 12 are extinguished.
On the other hand, if the detected current value Ij is equal to or higher than the ignition level, it is determined that there is no ignition abnormality and the process proceeds to step 8.
[0024]
In Step 8, when the first frame rod 41 detects the flame current of the main burner 11 and the current value Im is equal to or greater than the determination value, it is determined that the main burner 11 is burning normally and the supply gas is LPG. Judgment is made and combustion is continued with the combustion specification (S9).
[0025]
On the other hand, if the detected current value Im is less than the determination value, it is determined that the main burner 11 is not ignited (or is abnormally burning), and the supply gas is determined to be DME (S10). The on-off valve 32 is closed (S11), and the main burner 11 and the sensor burner 12 are extinguished.
[0026]
Then, the DME specification is set, that is, the gas flow rate is increased from that of the LPG so as to obtain the same input as when the LPG is supplied, and the rotation speed of the fan 60 is controlled so as to burn at an appropriate air-fuel ratio. DME air-fuel ratio control data is selected (S12), the process returns to step 2, the main burner 11 and sensor burner 12 are ignited (S3, S4), and if there is no ignition abnormality (S5), step Proceed to step 8.
At this time, since the DME specification is set, the main burner 11 normally burns, and in step 8, the detected current value Im becomes equal to or higher than the determination value, and the combustion continues with the DME specification (S9).
[0027]
After discriminating the gas type in this way, the required input Ip is calculated by multiplying the temperature difference between the hot water temperature set by a remote controller (not shown) and the incoming water temperature detected by the incoming water temperature thermistor 52 by the incoming water flow rate. Feed forward combustion control is started based on the air-fuel ratio control data corresponding to the seed. During this combustion control, if there is a temperature difference between the hot water temperature detected by the hot water temperature thermistor 53 and the set temperature, the proportional valve current I is continuously corrected so as to keep the outlet temperature of the heat exchanger 13 constant. At the same time, feedback combustion control is performed to correct the rotational speed of the fan 60 so that the gas amount and the air supply amount are always kept in a predetermined relationship.
[0028]
That is, when it is determined that the gas type has been changed, the feedforward combustion control and the feedback combustion control are performed by automatically switching to the air-fuel ratio control data suitable for the changed gas type.
When a hot water tap (not shown) is closed, the proportional valve 31 and the original open / close valve 32 are closed to shut off the gas supply to the burners 11 and 12 and extinguish the fire.
[0029]
As described above, in the water heater of the present embodiment, the gas type is accurately determined from the combustion state of the main burner 11 and the combustion state of the sensor burner 12.
For example, when the gas type is determined only by the combustion state of the main burner 11 without providing the sensor burner, when the main burner 11 abnormally burns, is it because DME of a gas type different from the combustion specification is supplied? Or it cannot be distinguished whether it is due to abnormal ignition. Therefore, it is erroneously determined that DME is supplied even if the ignition is abnormal.
On the other hand, in this embodiment, the gas type can be correctly determined according to the combination of signals indicating the combustion states of the two burners.
Even if the gas type is switched, the input can be made equal, and characteristics such as combustion and output of the water heater can be maintained well.
[0030]
In this way, LPG and DME can be used in parallel by switching appropriately according to their market price and supply status, which is economical. At this time, the user does not need to distinguish between the fuel gas and use the instrument, which is safe and easy to use.
In addition, since the combustion specification is automatically switched to the gas type, it is not necessary to change the gas type, which is convenient.
[0031]
Further, since the water heater of the present embodiment is a forced combustion type, if the combustion specifications are different, the flame of the main burner 11 often lifts or the flame itself is not formed. Since the main on-off valve 32 is closed and the fire is extinguished, leakage of raw gas can be prevented and it is safe.
[0032]
In addition, since the flame rod is used as a flame detection element for detecting the combustion state of the burner, the start-up is fast and the response is good, so that even if DME is supplied, abnormal combustion (or non-combustion) of the main burner 11 during gas type determination (Ignition) Time is short and safe.
[0033]
In addition, since the LPG specification is set in step 1 at the time of ignition operation, the gas flow to be used is less and it is safer to prevent an excessive input than in the case of initial setting to the DME specification.
That is, when the DME specification is initially set, since the DME is a low WI gas, the supply gas flow rate is higher than that of the LPG specification, and if LPG is supplied, the input becomes excessive. On the other hand, in this embodiment, since the LPG specification is set in step 1, excessive input can be prevented and it is safe.
[0034]
<< Second Embodiment >>
Next, a second embodiment will be described using the flowchart of FIG. In addition, a different part from 1st Embodiment is demonstrated, About the overlapping part, the same step number is attached | subjected and the description is abbreviate | omitted.
[0035]
Normal combustion only when a main burner that normally burns DME or LPG with different WI of fuel gas (forms a flame) and a specific fuel gas (here LPG) is supplied to the forced combustion gas water heater A sensor burner is provided. The main burner can form a flame with either DME or LPG by adjusting the shape of the flame mouth and the flame mouth load, or by providing a flame mouth for flame holding.
Table 2 shows the relationship between the combustion state of each burner and the determination result in this case.
[0036]
[Table 2]

[0037]
In the water heater provided with the above-described burner, gas type discrimination control is started and each burner is ignited (S1 to S4), as in the first embodiment.
Then, it is determined whether or not the flame current value Im of the main burner is less than the ignition level (S13).
If the detected current value Im is less than the ignition level, it is determined that the ignition is abnormal (S6), the proportional valve 31 and the main opening / closing valve 32 are closed (S7), and the main burner and the sensor burner are extinguished.
On the other hand, if the detected current value Im is equal to or higher than the ignition level, it is determined that there is no ignition abnormality and the process proceeds to step 14.
[0038]
In step 14, if the flame current value Ij of the sensor burner is equal to or greater than the determination value, it is determined that the sensor burner is normally combusting, and the supply gas is determined to be LPG, and combustion is continued with the combustion specification (S9). ).
[0039]
On the other hand, if the detected current value Ij is less than the determination value in step 14, it is determined that the supply gas is DME (S10), and the process proceeds to step 15. At this stage, the LPG specification is set. Then, the proportional valve 31 and the original opening / closing valve 32 are closed, the burners are extinguished, set to DME specifications (S12), and steps 2 to 10 are performed. At this stage, since the DME specification is set, the process proceeds from step 15 to step 9, and combustion is continued with the combustion specification.
[0040]
The hot water heater described above has the same effect as that of the first embodiment, and can be automatically and safely switched to the combustion specification of the determined gas type.
Further, since the sensor burner can be designed and manufactured so as to obtain a large difference in combustion state depending on the gas type, the gas type can be accurately determined by a combination with a signal indicating the combustion state of the main burner.
[0041]
Although the embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and it is needless to say that the present invention can be implemented in various modes without departing from the gist of the present invention.
For example, instead of the frame rod, a thermocouple may be used to detect the electromotive force and determine the gas type.
Further, after the gas type is determined and set to an appropriate combustion specification, the sensor burner may be extinguished.
[0042]
Further, the DME specification may be set in step 1.
In this case, in the first embodiment, as shown in Table 3, when both the main burner 11 and the sensor burner 12 are normally combusted, it is determined that the supply gas is DME and the combustion is continued, and only the sensor burner 12 is normal. When it is burned, it is determined that it is LPG, and the combustion specification is changed to LPG.
[0043]
[Table 3]

[0044]
On the other hand, in the second embodiment, as shown in Table 4, when both the main burner and the sensor burner are normally combusted, it is determined that the supply gas is DME and the combustion is continued. It is judged that there is, and the combustion specification is changed for LPG.
[0045]
[Table 4]

[0046]
In step 1, the combustion specification of the gas type is not always fixed to either LPG or DME, but the combustion specification of the normally burned gas type is set and stored, and the next time The gas type discrimination control may be started with the set specifications. In this case, if the supply gas type is the same as the previous time, the gas type discrimination control time is shortened.
[0047]
Further, instead of automatically switching the combustion specification, a notification means for notifying the determination result after gas type determination may be provided, and the operator who has received this notification may manually switch the combustion specification. As this notification means, what reports using auditory information, such as an alarm and a voice message, and visual information, such as a lamp and a display, may be used.
[0048]
Further, the present invention may be applied to a natural combustion type gas appliance such as a table stove instead of a forced combustion type gas appliance. In the case of the natural combustion type, a flame is easily formed even if the supply gas is different from the set specification. In particular, in the second embodiment, it becomes easy to design a main burner having such characteristics.
In addition, if a flame can be formed even if the supply gas differs from the set specification, such as a natural combustion type gas appliance, the combustion specification can be switched as it is without closing the gas supply path after the gas type is determined. May be.
[0049]
【The invention's effect】
As described above in detail, according to the gas combustion appliance of the first aspect of the present invention, the gas type is determined according to the combustion state of the main burner and the sensor burner. It is possible to determine whether it is due to abnormal ignition or to determine the gas type accurately.
As a result, by switching to a combustion specification suitable for the determined fuel gas, two types of fuel gas can be used in parallel.
[0050]
Furthermore, according to the gas combustion appliance of claim 2 of the present invention, since the gas type is discriminated according to the combustion state of the main burner and the sensor burner, whether the abnormal combustion of the sensor burner is due to the difference in the gas type, an abnormal ignition It is possible to determine whether it is caused by the gas, and to accurately determine the gas type.
As a result, by switching to a combustion specification suitable for the determined fuel gas, two types of fuel gas can be used in parallel.
Further, since the gas type is discriminated not by the main burner but by the sensor burner, a large difference in the combustion state due to the gas type can be taken and the gas type can be discriminated accurately.
[0051]
Furthermore, according to the gas combustion appliance of claim 3 of the present invention, when both of the burners are extinguished at the time of abnormal ignition, leakage of raw gas can be prevented and safety is ensured.
[0052]
Furthermore, according to the gas combustion appliance of claim 4 of the present invention, even if the gas type is switched, the input becomes equal, and characteristics such as combustion and output of the combustion appliance do not deteriorate.
Further, the combustion specification is automatically switched, and the gas type conversion work is not required.
[0053]
Furthermore, according to the gas combustion appliance of claim 5 of the present invention, since LPG and DME of the same gas supply form called a gas cylinder can be distinguished and switched and used, the fuel gas can be selected according to the market price, supply situation, etc. Is economical.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a gas combustion appliance as a first embodiment.
FIG. 2 is a flowchart showing an ignition sequence as the first embodiment.
FIG. 3 is a flowchart showing an ignition sequence as a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Main burner, 12 ... Sensor burner, 31 ... Proportional valve, 32 ... Original on-off valve, 41 ... 1st frame rod, 42 ... 2nd frame rod, 50 ... Controller, 60 ... Fan.

Claims (5)

Gas combustion for storing combustion specifications such as supply gas flow rate for two types of fuel gases having different Wobbe indices (WI) and controlling combustion in accordance with the combustion specifications of any one of the preset fuel gases In the instrument,
A main burner that normally burns when the set type of fuel gas is supplied, and abnormally burns when the other fuel gas is supplied;
A sensor burner that burns normally regardless of which of the two types of fuel gas is supplied,
A first flame detection element for detecting a flame state of the main burner;
A second flame detecting element for detecting a flame state of the sensor burner;
A gas type discriminating means for discriminating the type of fuel gas supplied according to a combination of a detection signal from the first flame detection element and a detection signal from the second flame detection element; Gas burning appliances. Gas combustion for storing combustion specifications such as supply gas flow rate for two types of fuel gases having different Wobbe indices (WI) and controlling combustion in accordance with the combustion specifications of any one of the preset fuel gases In the instrument,
A main burner that forms a predetermined flame regardless of which of the two types of fuel gas is supplied;
A sensor burner that normally burns when the set type of fuel gas is supplied, and abnormally burns when the other fuel gas is supplied;
A first flame detection element for detecting a flame state of the sensor burner;
A second flame detection element for detecting a flame state of the main burner;
A gas type discriminating means for discriminating the type of fuel gas supplied according to a combination of a detection signal from the first flame detection element and a detection signal from the second flame detection element; Gas burning appliances. 3. The gas combustion appliance according to claim 1, wherein when the abnormal signal is output from the second flame detection element, all the burners are extinguished. Automatic specification setting means for automatically setting the combustion specification of the main burner according to the determination result of the gas type determination means,
The gas combustion instrument according to any one of claims 1 to 3, wherein the combustion is performed with the same calorific value per unit time regardless of the WI of the fuel gas. 5. The gas combustion apparatus according to claim 1, wherein the low WI gas of the fuel gas is dimethyl ether, and the high WI gas is LP gas.

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