JP2016164480A - Boiler detecting clogging of water level detection cylinder communication pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the sign of clogging in a water level detection cylinder communication pipe connecting a boiler can body and a water level detection cylinder.SOLUTION: In a boiler having a boiler can body 13 composed of a heat transfer pipe for heating boiler water, and heating the boiler water in the boiler can body, a water level detection cylinder 8 for detecting a water level in the boiler can body is disposed independently from the boiler can body 13, and the boiler can body 13 and the water level detection cylinder 8 are connected by a water level detection cylinder communication pipe 9. A temperature difference detection device is disposed to detect the difference between a boiler water temperature in the water level detection cylinder 8 or a water level detection cylinder vicinity portion of the water level detection cylinder communication pipe 9, and the boiler water temperature at a lower portion in the boiler can body 13 or a boiler can body vicinity portion of the water level detection cylinder communication pipe, and occurrence of clogging of the water level detection cylinder communication pipe 9 is determined when the temperature difference becomes a set value for determining the clogging of the water level detection cylinder communication pipe, or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a boiler that detects a water level in a boiler can by a water level detection cylinder communicated by a water level detection cylinder communication pipe, and detects a clogging of the water level detection cylinder communication pipe.

As described in Japanese Patent No. 3443274 and Japanese Patent Application Laid-Open No. 2005-321146, the water level detection in the boiler is connected to the steam portion in the upper part of the boiler and the lower portion of the can water by the water level detection tube connecting pipe. This is done by providing a water level detection cylinder and detecting the water level in the water level detection cylinder. During boiler operation, in the boiler heat transfer tube, the water level rises and falls as the boiler water rises, so it is not possible to detect the direct water level. By detecting the water level in the detection cylinder, the accurate water level can be detected.

However, the water level detection tube connection pipe connecting the boiler can body and the water level detection tube is a thin tube, and clogging may occur due to accumulation of scale or sludge in the water level detection tube connection pipe. If the water level detection tube communication tube is completely blocked, the water level cannot be detected in the water level detection tube, but even if it is not completely blocked, the water in the water level detection tube communication tube is clogged. When the flow of the water becomes worse, a difference occurs between the water level in the water level detection cylinder and the water level in the boiler can, and the water level in the boiler can cannot be detected correctly.

If the water level in the boiler can does not drop even if the water level in the boiler can drops due to clogging of the water level detection tube connection pipe, the necessary water supply will not be performed and the water level in the boiler will drop. become. When heating is performed in a state where the water level in the can is lowered, the heat transfer section is overheated, and the boiler may be punctured when the heat transfer section is repeatedly overheated. Conversely, if the water level in the boiler can rises due to water supply but the water level in the water level detection cylinder does not rise, water will be supplied more than necessary, so the water level in the boiler can rise. In the boiler, since boiling of boiler water increases in the boiler, steam containing a large amount of can water is ejected from the steam pipe.

Therefore, in the invention described in Japanese Patent No. 3443274, two water level detection tubes are installed so that the water level is detected at the same height, and at the same height detected by each water level detection tube. When there is a time difference in the water level detection, the clogging of the water level detection tube communication pipe is detected. However, in this case, it is necessary to be able to detect the water level at the same height position, and when clogging occurs in both the water level detection tube connecting pipes at the same time, it cannot be detected. Further, in the invention described in Japanese Patent Application Laid-Open No. 2005-321146, the clogging of the water level detection tube connecting pipe is detected. However, in this case, the clogging cannot be detected unless after a carryover has occurred. There was a problem.

Japanese Patent No. 3443274 Japanese Patent Laying-Open No. 2005-321146

The problem to be solved by the present invention is to detect clogging by detecting signs of clogging at the stage where clogging has started due to accumulation of scale in the water level detection pipe connecting pipe connecting the boiler can body and the water level detection pipe. It is an object of the present invention to provide a boiler capable of predicting clogging before it occurs, and detecting a clogging abnormality in a water level detection tube connecting pipe when clogging progresses.

The invention according to claim 1 is a boiler having a boiler can body composed of a heat transfer tube or the like for heating boiler water and heating the boiler water in the boiler can body, and detecting the water level in the boiler can body The water level detection cylinder is installed separately from the boiler can body, and in the boiler where the boiler can body and the water level detection cylinder are connected by a water level detection cylinder connecting pipe, in the water level detection cylinder or in the water level detection cylinder There is a temperature difference detection device that detects the difference between the boiler water temperature in the vicinity of the water level detection cylinder of the connecting pipe and the boiler water temperature in the lower part of the boiler can or in the vicinity of the boiler can body of the water level detection cylinder connecting pipe. When the temperature difference is equal to or greater than the set value for determining the clogging of the water level detection cylinder communication pipe, it is determined that the clogging of the water level detection cylinder communication pipe has occurred.

The invention according to claim 2 is the boiler for detecting clogging of the water level detection cylinder communication pipe, wherein the setting value for clogging determination of the water level detection cylinder communication pipe is a judgment value for warning that detects signs of abnormality, It has a judgment value for warning for judging an abnormality.

According to a third aspect of the present invention, in the boiler for detecting the clogging of the water level detection cylinder communication pipe, the water level detection cylinder communication or the water level detection cylinder communication is performed at a time when there is no difference in the boiler water temperature in the boiler. The difference between the boiler water temperature in the vicinity of the water level detection tube of the pipe and the boiler water temperature in the lower portion of the boiler can or in the vicinity of the boiler can body of the water level detection tube connecting pipe is detected and stored as an offset value. When the clogging of the water level detection tube communication pipe is determined, correction for the offset value is performed.

According to a fourth aspect of the present invention, in the boiler for detecting clogging of the water level detection cylinder communication pipe, the water level detection cylinder communication or the water level detection cylinder communication is performed at a time when there is no difference in the boiler water temperature in the boiler. The difference between the boiler water temperature in the vicinity of the water level detection tube of the pipe and the boiler water temperature in the lower part of the boiler can or in the vicinity of the boiler can body of the water level detection tube connecting pipe is detected, and this difference is equal to or greater than the detection device abnormality determination value. In this case, it is determined that an abnormality has occurred in the detection device that determines clogging of the water level detection tube communication pipe.

According to a fifth aspect of the present invention, in the boiler for detecting the clogging of the water level detection tube connecting pipe, the water level is detected during the boiler temperature rise period immediately after the start of boiler combustion and during the steady combustion after the boiler temperature rises. The determination value for determining clogging of the detection tube communication pipe is set to a different value.

By carrying out the present invention, it is possible to detect clogging in the water level detection pipe connecting pipe connecting the boiler can body and the water level detection pipe, and to predict the clogging before the clogging occurs. In addition, it is possible to detect a clogging abnormality in the water level detection tube connecting pipe.

Flow chart of boiler in one embodiment of the present invention The flowchart of the program which judges the clogging of the water level detection cylinder communication pipe in one Example of this invention The graph which showed the water level detection pipe | tube thermocouple part temperature in the one Example of this invention, the thermocouple part temperature in a boiler, and its temperature difference

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a flow chart of a boiler in one embodiment of the present invention, FIG. 2 is a flowchart of a water level detection tube communication tube clogging detection program in one embodiment of the present invention, and FIG. 3 is a water level detection tube thermoelectric in one embodiment of the present invention. It is the graph which showed the pair part temperature, the thermocouple part temperature in a boiler, and its temperature difference. The boiler 1 burns in the portion of the boiler can body 13 provided in the center, and the combustion device 2 is provided in the upper part of the combustion chamber provided in the boiler can body 13 portion. A water supply pipe 6 is connected to the bottom of the boiler, a water supply pump 7 is installed in the middle of the water supply pipe 6, and the water supply pump 7 is operated to supply water to the boiler 1. The detection of the water level in the boiler is performed by the water level detection cylinder 8 provided outside the boiler can body 13. The water level detection cylinder 8 communicates with the boiler can 13 through a water level detection cylinder connecting pipe 9. The steam section in the upper part of the boiler, the upper part of the water level detection cylinder 8, the boiler water part in the lower part of the boiler and the water level detection cylinder 8. The water level in the boiler can 13 can be detected by the water level detection cylinder 8 by connecting the lower portions of the boilers 13 respectively.

The water level detection cylinder 8 is provided with an electrode rod E1 that detects the presence or absence of water at the water supply stop water level (E1 water level) and an electrode rod E2 that detects the presence or absence of water at the water supply start water level (E2 water level). Each water level electrode rod is electrically connected to an operation control device 4 that controls the operation of the boiler, and the operation control device 4 determines the water level based on the presence or absence of water detected by the water level electrode rod. The operation of the water supply pump 7 is controlled according to the water level. When the signal for detecting the absence of water is input from the water level electrode rod E2, the operation control device 4 outputs the water supply pump 7 and supplies water to the boiler. When the water level rises due to the water supply and a signal for detecting the presence of water is input from the water level electrode rod E1 to the operation control device 4, the operation control device 4 outputs an operation stop signal to the water supply pump 7. To stop.

When combustion is performed by the combustion device 2 with the boiler water being supplied into the boiler 1, the heat generated in the combustion device 2 heats the boiler water in the heat transfer tube of the boiler can body 13, and steam is generated in the boiler. Occur. The generated steam is separated into steam and boiler water by the steam separator 5, and the steam is taken out from the upper part of the steam separator 5 and supplied to the steam use location. The operation control device 4 also controls the amount of combustion in the boiler 1. In the boiler, the steam pressure detection device 3 detects the pressure in the boiler. When the pressure in the boiler is low, the boiler performs a combustion operation, and when the pressure increases, the combustion operation in the boiler is stopped. When the combustion amount is set in stages such as high combustion and low combustion, the combustion amount is changed according to the steam pressure value detected by the steam pressure detection device 3.

A water level detection cylinder thermocouple 11 is provided in the lower part of the water level detection cylinder, and a boiler thermocouple 12 is provided in the lower part of the boiler can body 13. The thermocouple provided at a position sandwiching the water level detection tube connecting tube 9 connects the same metals to form a circuit, and a voltmeter 10 for detecting a voltage flowing in the circuit is installed. The water level detection cylinder thermocouple 11 and the boiler thermocouple 12 are installed in the water level detection cylinder 8 and the boiler can 13, connected between them by a circuit, the voltage in the circuit is measured, and the measurement result is sent to the operation control device 4. Thus, a temperature difference between the water level detection cylinder 8 and the boiler can 13 can be detected.

A method for detecting clogging of the water level detection tube connecting pipe 9 will be described based on the flowchart shown in FIG. In the flowchart of FIG. 2, a failure of the detection device is first determined. The detection device failure determination is performed when all blows are performed. In all blows, initial water is supplied to supply new water to the boiler in order to discharge all boiler water from the boiler. In the initial water supply, the water supply pump 7 is operated until the water level in the water level detection cylinder 8 reaches the E1 water level that is the water supply stop water level, and when the water level reaches the E1 water level, the operation of the water supply pump 7 is stopped. When the initial water supply is completed, the boiler water temperature in the boiler does not vary depending on the position, and becomes a uniform temperature.

In this state, since there is no temperature difference between the boiler water in the water level detection cylinder 8 and the boiler water in the boiler can, the voltage between the water level detection cylinder thermocouple 11 and the boiler thermocouple 12 is normal if the detection device is normal. Even if measurement is performed, there is no temperature difference between the two. Here, if the value of the temperature difference TD between the water level detection cylinder 8 and the boiler can body 13 is equal to or larger than the preset detection device abnormality determination setting value T1, a failure has occurred in the detection device. It is determined that there is a failure, and an abnormality is reported for the detection device failure. If the value of the temperature difference TD at this time is less than the detection device abnormality determination setting value T1, it is determined that the detection device is normal, and then the value of the temperature difference TD is set to T0 by storing the offset value. Apply it. Since the boiler water temperature at this point should be the same for the water level detection cylinder 8 and the boiler can 13, if there is a temperature difference between the water level detection cylinder thermocouple 11 and the boiler thermocouple 12 at this stage, Then, the temperature difference is corrected when the clogging of the water level detection tube communication pipe 9 is performed later. Therefore, the temperature difference TD at this time is applied to T0.

Thereafter, when the operation is started with the boiler, the clogging in the water level detection tube communication pipe 9 is monitored. The operation control device 4 reads the voltage generated due to the temperature difference between the water level detection cylinder thermocouple 11 and the boiler thermocouple 12 and calculates the temperature difference TD. The clogging of the water level detection tube communication tube 9 is determined by whether or not the value obtained by subtracting the above T0 from the temperature difference TD is larger than a predetermined determination value.

If the boiler temperature is low immediately after the start of boiler combustion, the temperature rises due to the heat generated by the combustion in the boiler, but it is not heated directly in the water level detection cylinder, so as shown in FIG. There is a difference between the temperature at the thermocouple portion and the temperature at the water level detection tube thermocouple portion. The temperature inside the boiler continues to rise until the inside of the boiler reaches a predetermined pressure and temperature, and during this boiling time, the difference between the thermocouple partial temperature in the boiler and the water level detection thermocouple temperature continues to increase. Become. And even after the rise in the temperature in the boiler stops, the difference between the temperature in the boiler thermocouple portion and the temperature in the water level detection thermocouple portion is larger than usual for a while. Even at this stage, the clogging of the water level detection tube communication tube 9 is detected. When the value obtained by subtracting T0 from the temperature difference TD between the thermocouple portion in the boiler and the water level detection thermocouple portion is larger than the determination value T4 of the clogging abnormality in the water level detection tube connection tube, the water level detection tube connection tube It is determined that clogging has occurred, and a communication tube clogging abnormality is notified. The value of the determination value T4 in this case is set to a value larger than the determination value T3 of the clogging abnormality of the water level detection tube connecting pipe at the time of steady combustion performed later.

A pressure cut is performed to stop combustion by increasing the pressure in the boiler, and until the delay time t seconds elapses from the end of the boiling time, the clogging determination of the water level detection tube communication pipe is performed by the determination value T4. During subsequent steady combustion, the temperature difference between the thermocouple portion in the boiler and the water level detection thermocouple portion is small, and therefore determination is made with determination values T2 and T3 that are smaller than the determination value T4. When the value of the temperature difference TD-T0 is larger than T2 which is the determination value for the scale inspection, the scale inspection is notified. This notification of inspection does not have to be dealt with immediately, but an abnormality due to clogging is predicted in the future, and an abnormality is prevented early so that the clogging abnormality is prevented. When the value of the temperature difference TD-T0 is larger than the determination value T3 of the clogging abnormality of the water level detection cylinder communication pipe set to a value larger than the determination value T2, the notification of the clogging abnormality of the water level detection cylinder communication pipe is issued. I do. When the value of the temperature difference TD-T1 is smaller than the determination value T2 or T3, the abnormality is not notified.

When the water level detection tube connecting pipe 9 is normal, the boiler water temperature in the water level detection tube 8 and the boiler water temperature at the lower portion of the boiler can body are substantially the same temperature, so that no potential difference occurs. However, when clogging begins to occur due to the accumulation of scale in the water level detection tube connecting pipe 9, the flow of boiler water in the water level detection tube connecting pipe 9 is hindered, whereby the boiler can 13 and the water level detection tube 8 are blocked. Temperature difference between the two. If a potential difference is detected by a thermocouple circuit, if the potential difference becomes larger than a set value, it can be detected as a clogged connection tube. Since the temperature difference increases as the clogging progresses, if the temperature difference for determination is set in stages, clogging of the water level detection tube connecting pipe 9 can be detected at the sign stage. Since the determination is based on the temperature difference between the boiler can 13 and the water level detection cylinder 8, it is possible to detect clogging of the water level detection cylinder communication pipe regardless of the operation state of the boiler such as low combustion, high combustion, and stop. It becomes.

The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the art within the technical idea of the present invention. For example, in the above embodiment, the thermocouples are installed in the water level detection cylinder 8 and the boiler can body 13, but may be provided at both ends of the water level detection cylinder communication pipe 9.

DESCRIPTION OF SYMBOLS 1 Boiler 2 Combustion apparatus 3 Steam pressure detection apparatus 4 Operation control apparatus 5 Steam-water separator 6 Water supply pipe 7 Water supply pump 8 Water level detection pipe 9 Water level detection pipe connection pipe 10 Voltmeter 11 Water level detection pipe thermocouple 12 Boiler thermocouple 13 Boiler can body E1 Water supply stop water level E2 Water supply start water level

Claims (5)

A boiler having a heat transfer tube that heats boiler water, etc., and heating the boiler water in the boiler can body, and a water level detection cylinder for detecting the water level in the boiler can body and the boiler can body Is installed separately, and in the boiler where the boiler body and the water level detection cylinder are connected by a water level detection cylinder communication pipe, in the water level detection cylinder or in the vicinity of the water level detection cylinder of the water level detection cylinder communication pipe A temperature difference detection device is provided to detect the difference between the boiler water temperature and the boiler water temperature at the bottom of the boiler can or near the boiler can body of the water level detection tube communication tube. A boiler for detecting clogging of a water level detection tube communication pipe, wherein when it becomes equal to or greater than a set value for clogging determination, it is determined that the water level detection tube communication pipe is clogged. In the boiler for detecting clogging of the water level detection cylinder communication pipe according to claim 1, the setting value for clogging determination of the water level detection cylinder communication pipe is determined as a warning determination value for detecting an abnormality sign and an abnormality. A boiler for detecting clogging of a water level detection tube connecting pipe characterized by having a judgment value for warning to be performed. 3. The boiler for detecting clogging of the water level detection cylinder communication pipe according to claim 1 or 2, wherein the water level in the water level detection cylinder or the water level detection cylinder communication pipe is at a time when there is no difference in the boiler water temperature in the boiler. The difference between the boiler water temperature in the vicinity of the detection cylinder and the boiler water temperature in the lower part of the boiler can or in the vicinity of the boiler can body of the water level detection pipe connecting pipe is detected and stored as an offset value. A boiler for detecting clogging of a water level detection tube connecting pipe, wherein when determining whether the connecting pipe is clogged, the offset value is corrected. 4. A boiler for detecting clogging of a water level detection cylinder communication pipe according to claim 1, wherein the water level detection cylinder communication or the water level detection cylinder communication is performed at a time when there is no difference in the boiler water temperature in the boiler. The difference between the boiler water temperature in the vicinity of the water level detection tube of the pipe and the boiler water temperature in the lower part of the boiler can or in the vicinity of the boiler can body of the water level detection tube connecting pipe is detected, and this difference is equal to or greater than the detection device abnormality determination value. A boiler that detects clogging of the water level detection cylinder communication pipe, wherein it is determined that an abnormality has occurred in the detection device that determines clogging of the water level detection cylinder communication pipe. In the boiler which detects clogging of the water level detection cylinder connecting pipe according to any one of claims 1 to 4, the water level is in the boiler temperature rise period immediately after the start of boiler combustion and in the steady combustion after the boiler temperature rises. The boiler which detects the clogging of the water level detection pipe | tube connection pipe | tube characterized by setting the judgment value which determines clogging of the detection pipe | tube connection pipe | tube to a different value.

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