JP4168554B2

JP4168554B2 - Method for determining scale adhesion of water pipe in boiler

Info

Publication number: JP4168554B2
Application number: JP30617899A
Authority: JP
Inventors: 昭典川上; 立季小林; 直明湯浅
Original assignee: Miura Co Ltd
Current assignee: Miura Co Ltd
Priority date: 1999-10-28
Filing date: 1999-10-28
Publication date: 2008-10-22
Anticipated expiration: 2019-10-28
Also published as: JP2001124304A

Description

【０００１】
【発明の属する技術分野】
この発明は、ボイラの水管内に付着するスケ−ルの付着判定方法に関するものである。
【０００２】
【従来の技術】
ボイラの水管へ付着するスケ−ルは、缶体の寿命やボイラ効率の低下に大きく影響するため、水管の所定箇所に温度センサを設け、この温度センサの検出温度から水管内部に付着したスケ−ル厚みを判定し、必要に応じてスケ−ルを除去している。しかしながら、ボイラを冷態状態から起動させるときは、水管温度が定常沸騰時の温度へ向かってなだらかに上昇するので正確に判定することができるが、ボイラ内部に残留圧力があるときの再起動運転時には、定常沸騰状態になるまでの間は、熱伝達率が定常沸騰時と異なるため、前記水管の温度は、一時的に上昇するときがあり誤判定することがある。この温度の一時的上昇を許容してスケ−ル付着の判定をするには、判定温度を高く設定することがよく行われている。
【０００３】
【発明が解決しようとする課題】
しかしながら、従来の判定温度を高く設定する方法は、必然的に水管に付着したスケ−ル厚みが厚くなるまで検出できないことになり、判定精度が悪いことになる。ひいては水管に付着するスケ−ルは、缶体の寿命やボイラ効率の低下に大きく影響することになる。この発明は、ボイラ内部に残留圧力があるときの再起動運転時に熱伝達率が定常沸騰時と異なっても誤判定しないで、さらに判定温度を低く設定して、スケ−ル厚みが薄くても精度良くボイラの水管内に付着するスケ−ルの付着の判定ができる方法を提供することを目的としている。
【０００４】
【課題を解決するための手段】
この発明は前記課題を解決するためになされたもので、請求項１に記載の発明は、多数の水管により構成された缶体に圧力センサを設けるとともに、前記水管の所定箇所に温度センサを設け、この温度センサと前記圧力センサを制御器に接続し、前記圧力センサの信号に基づいてバーナの燃焼を制御して前記バーナの燃焼により前記水管内の水を沸騰させる構成のボイラにおいて、前記水管内のスケ−ル付着を判定するとき、前記缶体の内部に残留圧力があるときの再起動運転時には、前記バーナの燃焼開始後、定常沸騰状態になるまでの間は前記水管内のスケール付着を判定せず、所定の時間経過してから前記水管内のスケ−ル付着判定を行なうことを特徴としている。
【０００５】
さらに、請求項２に記載の発明は、多数の水管により構成された缶体に圧力センサを設けるとともに、前記水管の所定箇所に温度センサを設け、さらに前記水管の内部に缶水温度センサを配置し、前記温度センサ，前記圧力センサおよび前記缶水温度センサを制御器に接続した構成のボイラにおいて、前記水管内のスケ−ル付着を判定するとき、前記缶体の内部に残留圧力があるときの再起動運転時には、バーナの燃焼開始後、前記缶水温度センサが所定の缶水飽和温度に到達してから前記水管内のスケ−ル付着判定を行なうことを特徴としている。
【０００６】
【発明の実施の形態】
つぎに、この発明の実施の形態について説明すると、この発明は、多数の水管内に水を供給し、バーナにて燃料を燃焼させて蒸気を発生させるボイラにおいて、前記水管内のスケ−ル付着の判定を行なうときに実現することができる。前記水管へ付着するスケ−ルは、缶体の寿命やボイラ効率の低下に大きく影響するため、前記水管の所定箇所に温度センサを設け、この温度センサの検出温度から水管内部に付着したスケ−ル厚みを判定し、必要に応じてスケ−ルを除去している。
【０００７】
この発明においては、缶体の上部ヘッダと下部ヘッダとの間を多数の水管で連結し、前記缶体に圧力センサを備え、前記水管の所定箇所に温度センサを設けるとともに、この温度センサと前記圧力センサを、回線を介して制御器に接続した構成のボイラにおいて、前記缶体の内部に残留圧力があるときの再起動運転時には、スケ−ルの付着とは無関係な一時的な水管温度の上昇を除外して、バーナの燃焼開始後所定の時間経過してから、水管内のスケ−ル付着判定を行なうものである。
【０００８】
また、缶体の上部ヘッダと下部ヘッダとの間を多数の水管で連結し、前記缶体に圧力センサを備え、前記水管の所定箇所に温度センサを設けるとともに、前記水管の内部に缶水温度センサを配置し、前記温度センサと前記圧力センサおよび前記缶水温度センサを、回線を介して制御器に接続した構成のボイラにおいて、前記缶体の内部に残留圧力があるときの再起動運転時には、バーナの燃焼開始後、前記缶水温度センサが所定の缶水飽和温度に到達してから、すなわち水管内部の水が定常の沸騰状態になってから、水管内のスケ−ル付着判定を行なうものである。
【０００９】
【実施例】
以下、この発明の実施例について、図面に基づいて詳細に説明する。図１は、この発明の第一実施例を実施した多管式貫流ボイラの缶体の一部を破断して示す全体説明図である。缶体１の上部ヘッダ２と前記缶体１の下部ヘッダ３との間を多数の水管４で連結して中央部に燃焼室５を形成し、前記燃焼室５の上部にバーナ６を配置している。前記バーナ６には燃料供給ライン７を接続し、この燃料供給ライン７に燃料ポンプ８および燃料用電磁弁９をそれぞれ設け、燃焼用空気は送風機１０にて前記バーナ６へ送るようにしている。そして、前記缶体１には内部の圧力を検出する圧力センサ１１を設け、この圧力センサ１１の信号に基づいて制御器１２を介して前記バーナ６の燃焼を開始または停止させる。前記缶体１の水位制御器１３の信号に基づいて、給水ライン１４中の給水ポンプ１５を制御し、前記水管４内の水位をほぼ一定に保つようにしている。各機器と前記制御器１２は、回線１６，１６，…にて各々接続されている。
【００１０】
この第一実施例においては、温度センサ１７を前記水管４の所定位置に設け、この温度センサ１７が検出する水管外側温度を前記回線１６を介して前記制御器１２へ通報する。前記制御器１２には、予め蒸気圧力に対する缶水の飽和温度の対比値（図示省略）と、図２に示す水管内部に付着するスケ−ル厚みに対応して上昇する水管温度が入力してあり、前記温度センサ１７および前記圧力センサ１１からの信号に基づいて、演算処理され、スケ−ル付着の判定を行なうものである。ボイラを冷態状態から起動させるときは、水管温度が定常沸騰時の温度へ向かってなだらかに上昇するので正確に判定することができるが、図３に示すように、前記水管４の温度（前記温度センサ１７にて検出される温度で、図３においては点線で示している。）は、ボイラ内部に残留圧力があるときの再起動運転時には、定常沸騰状態になるまでの間は、熱伝達率が定常沸騰時と異なるため、一時的に上昇するときがある。なお、図３において、缶内圧力は実線で示している。
【００１１】
すなわち、図３において、ボイラの缶内に残留圧力Ｆがあるときの再起動運転時には、前記温度センサ１７付近の水管内の缶水飽和温度は、前記残留圧力Ｆがあるため高くなり、水側の熱伝達率は水が沸騰している通常運転時より低くなっており、水への熱の伝わりが悪く、前記水管４の温度（図３において、燃焼開始時温度Ｇ）が高くなり、最高温度Ａとなるときがある。このときの水管の温度上昇は、目的とする水管のスケ−ル付着の判定には、誤判定の要因となるものである。前記バーナ６の燃焼が継続され、水管内部の水が沸騰するようになると、水側の熱伝達率が良くなり前記水管４の温度も定常値Ｄに安定する。
【００１２】
この第一実施例においては、前記水管４内のスケ−ル付着を判定するとき、前記缶体１の内部に残留圧力Ｆがあるときの再起動運転時には、スケ−ルの付着とは無関係な一時的な水管温度の上昇を除外して、前記バーナ６の燃焼開始時間Ｊから所定時間Ｋの経過後、スケ−ルの付着判定を行う。このときの設定水管温度は、図３に示すように設定温度Ｅとしている。これは、従来、前記最高温度Ａよりも高く設定されていた設定温度Ｂよりも低い温度設定でスケ−ル付着判定を行うことができることを意味しており、したがってスケ−ル付着判定が、より薄いスケ−ル厚みの下で行なうことができる。これに伴い、スケ−ル付着判定の精度も向上することになる。
【００１３】
つぎに、図４は、この発明の第二実施例を実施した多管式貫流ボイラの缶体の一部を破断して示す全体説明図である。缶体１の上部ヘッダ２と前記缶体１の下部ヘッダ３との間を多数の水管４で連結して中央部に燃焼室５を形成し、前記燃焼室５の上部にバーナ６を配置している。前記バーナ６には燃料供給ライン７を接続し、この燃料供給ライン７に燃料ポンプ８および燃料用電磁弁９をそれぞれ配置し、燃焼用空気は送風機１０にて前記バーナ６に送るようにしている。そして、前記缶体１には内部の圧力を検出する圧力センサ１１を設け、この圧力センサ１１の信号に基づいて制御器１２を介して前記バーナ６の燃焼を開始または停止させる。前記缶体１の水位制御器１３の信号に基づいて、給水ライン１４中の給水ポンプ１５を制御し、前記水管４内の水位をほぼ一定に保つようにしている。各機器と前記制御器１２は、回線１６，１６，…にて各々接続されている。
【００１４】
この第二実施例においては、温度センサ１７を前記水管４の所定位置に設けるとともに、前記水管４の内部に缶水温度センサ１８を配置し、前記温度センサ１７，前記圧力センサ１１および前記缶水温度センサ１８を前記回線１６を介して制御器１２に各々接続している。前記温度センサ１７が検出する水管外側温度を前記回線１６を介して前記制御器１２へ通報する。前記制御器１２には予め蒸気圧力に対する缶水の飽和温度の対比値（図示省略）と、図２に示すように、水管内部に付着するスケ−ル厚みに対応して上昇する水管温度が入力してあり、前記温度センサ１７および前記圧力センサ１１からの信号に基づいて、演算処理され、スケ−ル付着の判定を行なうものである。ボイラを冷態状態から起動させるときは、水管温度が定常沸騰時の温度へ向かってなだらかに上昇するので正確に判定することができるが、図５に示すように、前記水管４の温度（前記温度センサ１７にて検出される温度で、図５においては、点線で示している。）は、ボイラ内部に残留圧力があるときの再起動運転時には、定常沸騰状態になるまでの間は、熱伝達率が定常沸騰時と異なるため、一時的に上昇するときがある。なお、図５において、缶内圧力は実線で示しており、また前記缶水温度センサ１８で検出される温度は一点鎖線で示している。
【００１５】
すなわち、図５においては、ボイラの缶内に残留圧力Ｆがあるときの再起動運転時には、前記温度センサ１７付近の水管内の缶水飽和温度は、前記残留圧力Ｆがあるため高くなり、水側の熱伝達率は水が沸騰している通常運転時より低くなっており、水への熱の伝わりが悪く前記水管４の温度（図５において、燃焼開始時温度Ｇ）が高くなる。このときの水管の温度上昇は、目的とする水管のスケ−ル付着の判定には、誤判定の要因となるものである。前記バーナ６の燃焼が継続され、水管内部の水が沸騰するようになると、水側の熱伝達率が良くなり前記水管４の温度も定常値Ｄに安定する。
【００１６】
この発明の第二実施例においては、前記水管４内のスケ−ル付着を判定するとき、前記缶体１の内部に残留圧力Ｆがあるときの再起動運転時には、前記バーナ６の燃焼開始後、前記缶水温度センサ１８に基づいて検出される温度（図５においては、燃焼開始時温度Ｈ）が所定の缶水飽和温度Ｃに到達してから前記水管４内のスケ−ル付着判定を行ない、スケ−ルの付着とは無関係な一時的な水管温度の上昇を除外して，すなわち水管内部の水が定常の沸騰状態になってから、スケ−ル付着判定を行う。このときの設定水管温度は、図５に示すように設定温度Ｅとしている。これは、従来、前記最高温度Ａよりも高く設定されていた設定温度Ｂよりも低い温度設定でスケ−ル付着判定を行うことができることを意味しており、したがってスケ−ル付着判定が、より薄いスケ−ル厚みの下で行なうことができる。これに伴い、スケ−ル付着判定の精度も向上することになる。
【００１７】
前記２つの実施例では、前記バーナ６が環状に配列された水管の上部にあるボイラを例として説明したが、前記バーナ６が水管の横部に配置される，いわゆる角型水管ボイラなどでも同様に実施することができる。
【００１８】
【発明の効果】
以上のように、この発明によれば、ボイラ内部に残留圧力があるときの再起動運転時、スケール付着とは無関係な一時的な水管温度の上昇を除外して、判定することができ、さらに判定温度を低く設定して、スケール厚みが薄くても精度良くボイラの水管内に付着するスケールを判定することができる。
【図面の簡単な説明】
【図１】この発明の第一実施例を実施した多管式貫流ボイラの缶体の一部を破断して示す全体説明図である。
【図２】水管内部に付着するスケ−ル厚みに対応して上昇する水管温度の関係を示す説明図である。
【図３】ボイラの運転状況により変化する水管温度の関係を示す説明図である。
【図４】この発明の第二実施例を実施した多管式貫流ボイラの缶体の一部を破断して示す全体説明図である。
【図５】ボイラの運転状況により変化する缶水温度の関係を示す説明図である。
【符号の説明】
１缶体
４水管
６バーナ
１１圧力センサ
１２制御器
１７温度センサ
１８缶水温度センサ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for determining adhesion of a scale adhering to a water pipe of a boiler.
[0002]
[Prior art]
Since the scale adhering to the water pipe of the boiler greatly affects the life of the can and the decrease in boiler efficiency, a temperature sensor is provided at a predetermined location of the water pipe, and the scale adhering to the inside of the water pipe is detected from the temperature detected by this temperature sensor. The thickness of the reel is determined and the scale is removed as necessary. However, when starting the boiler from the cold state, the water pipe temperature rises gently toward the temperature at the steady boiling, so it can be accurately determined, but restart operation when there is residual pressure inside the boiler Sometimes, until the steady boiling state is reached, the heat transfer coefficient is different from that during steady boiling, so the temperature of the water pipe may rise temporarily and may be erroneously determined. In order to determine the scale adhesion while allowing the temperature to rise temporarily, the determination temperature is often set high.
[0003]
[Problems to be solved by the invention]
However, the conventional method of setting the determination temperature high inevitably cannot be detected until the thickness of the scale attached to the water pipe becomes thick, and the determination accuracy is poor. As a result, the scale adhering to the water pipe greatly affects the life of the can body and the decrease in boiler efficiency. Even if the heat transfer coefficient is different from that during steady boiling at the time of restart operation when there is residual pressure inside the boiler, this invention does not make an erroneous determination, and even if the determination temperature is set lower and the scale thickness is small. An object of the present invention is to provide a method capable of accurately determining the adhesion of the scale adhering to the boiler water pipe.
[0004]
[Means for Solving the Problems]
The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 provides a pressure sensor in a can body constituted by a large number of water pipes, and a temperature sensor at a predetermined location of the water pipe. In the boiler configured to connect the temperature sensor and the pressure sensor to a controller, control combustion of a burner based on a signal of the pressure sensor, and boil water in the water pipe by combustion of the burner. tract of scale - when determining the Le deposition, the restart operation when there is residual pressure in the interior of the can body, after combustion initiation of the burner, the until a steady boil scale deposition of the water pipe It is characterized in that determination of adhesion of the scale in the water pipe is performed after a predetermined time has passed.
[0005]
Furthermore, in the invention described in claim 2, a pressure sensor is provided in a can body constituted by a large number of water pipes, a temperature sensor is provided at a predetermined position of the water pipe, and a can water temperature sensor is disposed inside the water pipe. In the boiler having a configuration in which the temperature sensor, the pressure sensor, and the can water temperature sensor are connected to a controller, when determining the scale adhesion in the water pipe, when there is a residual pressure inside the can body In the restart operation, after the combustion of the burner is started, the scale adhering determination in the water pipe is performed after the can water temperature sensor reaches a predetermined can water saturation temperature.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described. In the present invention, in a boiler in which water is supplied into a number of water pipes and fuel is burned by a burner to generate steam, the scale adhering in the water pipes is attached. This can be realized when making the determination. Since the scale adhering to the water pipe greatly affects the life of the can body and the decrease in boiler efficiency, a temperature sensor is provided at a predetermined location of the water pipe, and the scale adhering to the inside of the water pipe is detected from the temperature detected by the temperature sensor. The thickness of the reel is determined and the scale is removed as necessary.
[0007]
In this invention, the upper header and the lower header of the can body are connected by a large number of water pipes, the can body is provided with a pressure sensor, and a temperature sensor is provided at a predetermined location of the water pipe. In a boiler configured to connect a pressure sensor to a controller via a line, during a restart operation when there is residual pressure inside the can body, the temperature of the temporary water pipe temperature is irrelevant to scale adhesion. Excluding the rise, the scale adherence determination in the water pipe is performed after a predetermined time has elapsed after the start of combustion of the burner.
[0008]
Further, the upper header and the lower header of the can body are connected by a number of water pipes, the can body is provided with a pressure sensor, a temperature sensor is provided at a predetermined location of the water pipe, and the temperature of the can water is provided inside the water pipe. In a boiler configured to arrange a sensor and connect the temperature sensor, the pressure sensor, and the can water temperature sensor to a controller via a line, during a restart operation when there is residual pressure inside the can body After the combustion of the burner starts, after the can water temperature sensor reaches a predetermined can water saturation temperature, that is, after the water in the water tube reaches a steady boiling state, the scale adhesion in the water tube is determined. Is.
[0009]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall explanatory view showing a part of a can body of a multitubular once-through boiler in which a first embodiment of the present invention is implemented. The upper header 2 of the can body 1 and the lower header 3 of the can body 1 are connected by a number of water pipes 4 to form a combustion chamber 5 at the center, and a burner 6 is disposed above the combustion chamber 5. ing. A fuel supply line 7 is connected to the burner 6, and a fuel pump 8 and a fuel solenoid valve 9 are provided in the fuel supply line 7, and combustion air is sent to the burner 6 by a blower 10. The can body 1 is provided with a pressure sensor 11 for detecting an internal pressure, and combustion of the burner 6 is started or stopped via a controller 12 based on a signal from the pressure sensor 11. Based on the signal from the water level controller 13 of the can 1, the water pump 15 in the water supply line 14 is controlled to keep the water level in the water pipe 4 substantially constant. Each device and the controller 12 are connected to each other through lines 16, 16,.
[0010]
In the first embodiment, a temperature sensor 17 is provided at a predetermined position of the water pipe 4, and the temperature outside the water pipe detected by the temperature sensor 17 is notified to the controller 12 via the line 16. The controller 12 previously receives a contrast value (not shown) of the saturation temperature of the can water with respect to the steam pressure and a water pipe temperature that rises corresponding to the thickness of the scale adhering to the inside of the water pipe shown in FIG. Yes, on the basis of signals from the temperature sensor 17 and the pressure sensor 11, a calculation process is performed to determine whether the scale adheres. When the boiler is started from the cold state, the water pipe temperature gradually rises toward the temperature at the time of steady boiling, so that it can be accurately determined. However, as shown in FIG. The temperature detected by the temperature sensor 17 and indicated by a dotted line in FIG. 3) indicates the heat transfer during the restarting operation when there is residual pressure inside the boiler until it reaches a steady boiling state. Since the rate is different from that during steady boiling, it may rise temporarily. In FIG. 3, the pressure inside the can is indicated by a solid line.
[0011]
That is, in FIG. 3, during the restart operation when there is a residual pressure F in the boiler can, the can water saturation temperature in the water pipe near the temperature sensor 17 becomes high due to the residual pressure F, and the water side The heat transfer coefficient of water is lower than that in normal operation in which water is boiling, the heat transfer to water is poor, the temperature of the water pipe 4 (in FIG. 3, the temperature G at the start of combustion) increases, Sometimes temperature A is reached. The temperature rise of the water pipe at this time becomes a cause of erroneous determination in the determination of the scale adhesion of the target water pipe. When the combustion of the burner 6 is continued and the water in the water pipe boils, the heat transfer coefficient on the water side is improved and the temperature of the water pipe 4 is also stabilized at the steady value D.
[0012]
In this first embodiment, when the scale adhesion in the water pipe 4 is determined, it is irrelevant to the scale adhesion during the restart operation when the residual pressure F is present inside the can 1. Excluding the temporary rise in the water pipe temperature, after a predetermined time K has elapsed from the combustion start time J of the burner 6, the scale adhesion determination is performed. The set water pipe temperature at this time is set to the set temperature E as shown in FIG. This means that the scale adhesion determination can be performed at a temperature setting lower than the set temperature B that has been conventionally set higher than the maximum temperature A. Therefore, the scale adhesion determination is more effective. It can be performed under a thin scale thickness. Along with this, the accuracy of the scale adhesion determination is also improved.
[0013]
FIG. 4 is an overall explanatory view showing a part of the can of the multi-tube once-through boiler in which the second embodiment of the present invention is implemented. The upper header 2 of the can body 1 and the lower header 3 of the can body 1 are connected by a number of water pipes 4 to form a combustion chamber 5 at the center, and a burner 6 is disposed above the combustion chamber 5. ing. A fuel supply line 7 is connected to the burner 6, and a fuel pump 8 and a solenoid valve 9 for fuel are arranged in the fuel supply line 7, respectively, and combustion air is sent to the burner 6 by a blower 10. . The can body 1 is provided with a pressure sensor 11 for detecting an internal pressure, and combustion of the burner 6 is started or stopped via a controller 12 based on a signal from the pressure sensor 11. Based on the signal from the water level controller 13 of the can 1, the water pump 15 in the water supply line 14 is controlled to keep the water level in the water pipe 4 substantially constant. Each device and the controller 12 are connected to each other through lines 16, 16,.
[0014]
In this second embodiment, a temperature sensor 17 is provided at a predetermined position of the water pipe 4, and a can water temperature sensor 18 is disposed inside the water pipe 4, so that the temperature sensor 17, the pressure sensor 11 and the can water are disposed. A temperature sensor 18 is connected to the controller 12 via the line 16. The temperature outside the water pipe detected by the temperature sensor 17 is reported to the controller 12 via the line 16. The controller 12 previously receives a contrast value (not shown) of the saturation temperature of the can water with respect to the steam pressure and a water pipe temperature that rises corresponding to the thickness of the scale attached to the inside of the water pipe as shown in FIG. Thus, calculation processing is performed on the basis of signals from the temperature sensor 17 and the pressure sensor 11, and determination of scale adhesion is made. When the boiler is started from the cold state, the water pipe temperature gradually increases toward the temperature at the steady boiling, so that it can be accurately determined. However, as shown in FIG. The temperature detected by the temperature sensor 17 (shown by a dotted line in FIG. 5) indicates that during the restart operation when there is residual pressure inside the boiler, Since the transmission rate is different from that during steady boiling, it may rise temporarily. In FIG. 5, the can internal pressure is indicated by a solid line, and the temperature detected by the can water temperature sensor 18 is indicated by a one-dot chain line.
[0015]
That is, in FIG. 5, during the restarting operation when the residual pressure F is in the boiler can, the can water saturation temperature in the water pipe near the temperature sensor 17 becomes high due to the residual pressure F. The heat transfer coefficient on the side is lower than that in the normal operation in which water is boiling, the heat transfer to water is poor, and the temperature of the water pipe 4 (temperature G at the start of combustion in FIG. 5) is high. The temperature rise of the water pipe at this time becomes a cause of erroneous determination in the determination of the scale adhesion of the target water pipe. When the combustion of the burner 6 is continued and the water in the water pipe boils, the heat transfer coefficient on the water side is improved and the temperature of the water pipe 4 is also stabilized at the steady value D.
[0016]
In the second embodiment of the present invention, when the scale adhesion in the water pipe 4 is determined, during the restarting operation when the residual pressure F is present in the can 1, the combustion of the burner 6 is started. The scale adhesion determination in the water pipe 4 is performed after the temperature detected based on the can water temperature sensor 18 (in FIG. 5, the temperature H at the start of combustion) reaches a predetermined can water saturation temperature C. Then, excluding the temporary water pipe temperature rise that is not related to the scale adhesion, that is, after the water in the water pipe is in a steady boiling state, the scale adhesion judgment is performed. The set water pipe temperature at this time is set to the set temperature E as shown in FIG. This means that the scale adhesion determination can be performed at a temperature setting lower than the set temperature B that has been conventionally set higher than the maximum temperature A. Therefore, the scale adhesion determination is more effective. It can be performed under a thin scale thickness. Along with this, the accuracy of the scale adhesion determination is also improved.
[0017]
In the two embodiments, the boiler at the upper part of the water pipe in which the burner 6 is arranged in an annular manner has been described as an example. Can be implemented.
[0018]
【The invention's effect】
As described above, according to the present invention, during the restart operation when there is residual pressure inside the boiler , it can be determined by excluding a temporary water pipe temperature increase that is unrelated to scale adhesion , By setting the determination temperature low, it is possible to accurately determine the scale attached to the boiler water pipe even if the scale thickness is thin.
[Brief description of the drawings]
FIG. 1 is an overall explanatory view showing a part of a can of a multitubular once-through boiler according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing the relationship of the water pipe temperature rising corresponding to the thickness of the scale attached inside the water pipe.
FIG. 3 is an explanatory diagram showing the relationship of water pipe temperature that varies depending on the operating condition of the boiler.
FIG. 4 is an overall explanatory view showing a part of a can body of a multitubular once-through boiler according to a second embodiment of the present invention.
FIG. 5 is an explanatory diagram showing the relationship of the temperature of the can water that changes depending on the operation status of the boiler.
[Explanation of symbols]
1 Can 4 Water Pipe 6 Burner 11 Pressure Sensor 12 Controller 17 Temperature Sensor 18 Can Water Temperature Sensor

Claims

While providing the pressure sensor 11 in the can 1 comprised by many water pipes 4, the temperature sensor 17 is provided in the predetermined location of the water pipe 4, this temperature sensor 17 and the pressure sensor 11 are connected to the controller 12, In the boiler configured to control the combustion of the burner 6 based on the signal of the pressure sensor 11 and boil the water in the water pipe 4 by the combustion of the burner 6, when determining the scale adhesion in the water pipe 4; wherein the restart operation when there is an internal residual pressure of the can body 1, after the start of combustion of the burner 6, until a steady boil does not determine the scale deposition in 4 the water tube, a predetermined time A method for determining the scale adhesion of a water pipe in a boiler, wherein the scale adhesion determination in the water pipe 4 is performed after a lapse of time.

While providing the pressure sensor 11 in the can 1 comprised by many water pipes 4, the temperature sensor 17 is provided in the predetermined location of the water pipe 4, and also the water temperature sensor 18 is arrange | positioned inside the water pipe 4, and the said temperature In a boiler having a configuration in which the sensor 17, the pressure sensor 11, and the can water temperature sensor 18 are connected to the controller 12, when determining the scale adhesion in the water pipe 4, the residual pressure is present inside the can body 1. In a certain restart operation, after the combustion of the burner 6 is started, the scale adhering determination in the water pipe 4 is performed after the can water temperature sensor 18 reaches a predetermined can water saturation temperature. A method for determining the scale adhesion of a water pipe in a boiler.