JP2005321146A - Boiler capable of determining abnormality in detecting water level - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To notify the abnormality before severe damage such as puncturing occurs because of overheating a boiler, by properly detecting the abnormality in detecting a water level in a case when the abnormality such as clogging caused by mixing of foreign matters in a communication pipe of a water level detecting cylinder 2 occurs, and the water level can not be accurately detected. <P>SOLUTION: The boiler for heating the boiler water by heating a heat transfer part 1 composed of a water pipe 8 and the like, wherein the water level detecting cylinder 2 is mounted in a state of being connected with the heat transfer part 1 through the communication pipe 3, and the water supply is controlled on the basis of the water level in the water level detecting cylinder 2, comprises a heat input measuring device 6 for measuring the heat input to the boiler at a specific time and a water supply measuring device for measuring the water supply to the boiler at the same time, and an abnormality determining device is mounted to measure and compare the heat input to the boiler and the water supply to the boiler, and to determine the abnormality when a ratio of the heat input to the boiler and the water supply to the boiler is outside of a specific range. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a boiler that detects an abnormality in water level detection.

  In the case of a boiler that heats can water by heating a heat transfer section composed of a water pipe, etc., as described in Japanese Patent Publication No. 2-10327, a connection pipe connects to the heat transfer section. A water level detection cylinder is provided, and the water level in the heat transfer section is detected by the water level detection cylinder. The water level detection mechanism in the water level detection cylinder is provided with a plurality of electrode rods having different bottom end heights, and detects the water level depending on whether or not each electrode rod is in contact with the water surface. The water level detection cylinder is connected to the heat transfer section of the boiler through a connecting pipe, and the water level in the water level detection cylinder is equal to the water level in the heat transfer section, so water is supplied to the boiler based on the water level in the water level detection cylinder. By controlling, the water level of the boiler heat transfer section can be maintained appropriately.

  However, the connecting pipe connecting the heat transfer section side of the boiler and the water level detection cylinder is a thin pipe, and clogging may occur due to sludge and scale delamination flowing into the connecting pipe. Even if the connecting pipe is not completely blocked, if the flow of water has deteriorated due to clogging, the water level in the water level detection cylinder appears later than the water level in the heat transfer section, so the water level in the boiler heat transfer section Cannot be detected correctly. If the connecting pipe is clogged, the water level in the water level detection cylinder will decrease only slightly even if the water level in the heat transfer part decreases.Therefore, when the water level in the water level detection cylinder reaches the water supply start water level, Will have fallen significantly. When the water level in the can is lowered, the heat transfer section may be overheated, and when the heat transfer section is repeatedly heated, the boiler may be punctured. On the other hand, if the water level in the water level detection cylinder rises slightly due to the water supply, but the water level in the water level detection cylinder rises only slightly, the water level in the heat transfer part will rise significantly when the water level in the water level detection cylinder reaches the water supply stop water level. In this case, since the amount of boiling water increases, steam containing a large amount of can water is ejected from the steam pipe.

If the correct water level cannot be detected due to clogging of the connecting pipe, do not start water supply even if the water level in the can has dropped, or do not stop water supply even if the water level in the can has risen Therefore, one water supply stop time and water supply execution time become longer. Therefore, it was considered that the water supply stop time or the water supply execution time was detected and it was determined that clogging occurred when the water supply stop time was longer than the predetermined time. However, since the water supply execution time and the water supply stop time change depending on the load of the boiler and the like, there is a problem that it is not possible to accurately detect an abnormality in water level detection by judgment based on time.
Japanese Patent Publication No. 2-10327

  The problem to be solved by the present invention is that if an abnormality such as clogging occurs due to foreign matter mixed in the connecting pipe of the water level detection cylinder, the correct water level cannot be detected. By detecting appropriately, it is intended to be able to report an abnormality before serious damage such as puncture due to overheating of the boiler.

The boiler for determining an abnormality in water level detection according to the first aspect of the present invention is a boiler that heats canned water by heating a heat transfer section composed of a water pipe or the like, and is connected to the heat transfer section. In the boiler that controls the water supply based on the water level in the water level detection cylinder, a heat input amount measuring device that measures the heat input amount to the boiler at a predetermined time, A water supply measuring device that measures the amount of water supplied to the boiler at the same time is installed, and the amount of heat input to the boiler and the amount of water supplied to the boiler are measured and compared, and the amount of heat input to the boiler and the amount of water supplied to the boiler are compared. An abnormality determination device that determines an abnormality when the ratio is out of a predetermined range is provided.
In the boiler according to the first aspect of the invention for determining abnormality in water level detection according to the second aspect of the invention, the calculated water supply amount is calculated from the amount of heat input to the boiler, and the calculated water supply amount and the water supply amount measuring device are measured A water level detection abnormality characterized by determining an abnormality when a difference in measured water supply amount is obtained by calculation and the difference value is larger than a determination value determined between 10% and 50% of the calculated water supply amount Boiler to judge.

  By carrying out the present invention, it is possible to appropriately determine an abnormality in water level detection, and it is possible to prevent problems such as overheating of the boiler.

  An embodiment of the present invention will be described with reference to the drawings. FIGS. 1 to 4 are sectional views of a boiler implementing the present invention, and FIGS. 1 and 2 show a state in which the water level in the water level detection cylinder correctly reflects the water level of the heat transfer section, FIG. 3 and FIG. 4 shows a state where the water level in the water level detection cylinder and the water level in the heat transfer section are different due to clogging of the connecting pipe. 1 and 3 show a state in which the water level detection in-cylinder water level becomes the water supply start water level, and FIGS. 2 and 4 show a state in which the water level detection in-cylinder water level becomes the water supply stop water level.

  The main body of the boiler is composed of a heat transfer section 1 composed of a large number of water pipes 8 and heating means 4 for heating the water pipes 8, and the water pipes 8 are connected to headers provided at the top and bottom. A water supply pipe is connected to the lower header, and water is supplied into each water pipe of the heat transfer section 1 by operating a water supply pump 5 provided in the middle of the water supply pipe. The can water in the water pipe rises in temperature by heating the water pipe and generates steam. When the can water boils in the water pipe, the can water rises due to boiling, so that the steam and the can water are sent to the upper header in a mixed state. Therefore, the steam separator 9 is provided in connection with the upper header, and the steam / water separator 9 separates the steam and the can water to take out only the steam, and the can water is returned to the lower header. Yes.

  The water level in the boiler is detected by a water level detection cylinder 2 connected by a connecting pipe 3 to the steam portion at the upper part of the boiler and the lower portion of the can water. The water level detection cylinder 2 is provided with a plurality of electrode rods having different lower end positions, and the current level is detected by determining whether each electrode rod is in contact with water by passing an electric current through each electrode rod. Do.

  Information on the water level detected by the water level detection cylinder 2 is sent to the control device 6, and when the control device 6 detects that the water level has become lower than the water supply start water level, it outputs an operation command to the water supply pump 5 and supplies it to the boiler. When water supply is performed and it is detected that the water level has become higher than the water supply stop water level due to water supply, the operation command for the water supply pump 5 is stopped and water supply to the boiler is stopped. A flow meter 10 that is a feed water flow rate measuring device that measures the feed water flow rate is provided in the middle of the feed water path, and information on the feed water amount measured by the flow meter 10 is sent to the controller 6. The control device 6 also controls heating to the heat transfer section 1 and controls the heating and calculates the heat input to the boiler as a heat input measuring device.

  In the case of FIGS. 1 and 2, the communication pipe 3 is not clogged, and the water level detection cylinder 2 correctly reflects the water level of the heat transfer section 1. Therefore, the water level of the heat transfer section 1 can be appropriately controlled by performing the water supply control based on the water level of the water level detection cylinder 2. In the case of FIG. 1 which is the water level at which water supply is started, water supply is started in a state before the water level of the heat transfer section 1 becomes too low, so that the water pipe 8 has an amount necessary for preventing overheating of the water pipe 8. Can water is present and the water tube 8 is not overheated. Further, in FIG. 2, since water supply is stopped before the water level of the heat transfer section 1 becomes too high, the amount of water that can be lifted so as to cause carryover even if the water is lifted by boiling in the water pipe 8. However, the steam / water separator 9 can separate the steam into the can water and take out only the steam.

  Whether or not the water level control of the heat transfer unit 1 is appropriate is determined by the control device 6 provided with an abnormality determination device, an abnormality notification device, or the like. In the control device 6, the amount of water supply during that period is calculated from the amount of heat input to the boiler in a fixed time such as one hour. Since the amount of heat input to the boiler and the required amount of water supply are substantially proportional, if the amount of heat input is determined, the amount of water supply can be calculated. When the calculated water supply amount is calculated from the heat input amount, it is compared with the measured water supply amount measured by the flow meter 10 at the same time, and the difference is calculated. When appropriate water level control is performed, the difference between the calculated water supply and the measured water supply becomes small.If the difference is smaller than the judgment value, there is an abnormality in the water level detection such as clogging of the connecting pipe. Can be determined not to occur.

  In the case of FIGS. 3 and 4, the connecting pipe is not completely clogged, but the water level change of the water level detection cylinder 2 is delayed because the flow path area is narrowed. In FIG. 3, water supply is started when the water level in the water level detection cylinder 2 drops to the water supply start water level, but the heat transfer section water level at this time is lower than the normal water level control range. If the water level of the heat transfer section 1 is low, the amount of boiling water will be small, and the water pipe 8 will be overheated because cooling by the can water will be insufficient at the upper part of the water pipe. In FIG. 4, water supply is started when the water level in the water level detection cylinder 2 is lowered to the water supply start water level, and the heat transfer section water level at this time is higher than the normal water level control range. When the water level of the heat transfer unit 1 is high, the amount of boiling water increases, and a large amount of can water is sent to the steam separator 9. If the amount of can water reaching the steam / water separator 9 is large, the steam / water separator 9 cannot separate the can water, and a carry-over in which the can water is taken out together with steam occurs. When the flow path area in the connecting pipe 3 is narrowed, the water supply starts and stops later, so that the water level is greatly lowered and greatly increased.

  When a carry-over occurs, the amount of canned water decreases accordingly, so that water supply is required, and the amount of water supply within a certain time increases. The reason why the measured water supply amount measured by the flow meter 10 is larger than the calculated water supply amount calculated from the heat input amount to the boiler during a certain time is that can water is discharged due to carryover. Therefore, in the control device 6, the communication pipe 3 is clogged when the measured water supply amount measured by the flow meter 10 is larger than the determination amount with respect to the calculated water supply amount calculated from the heat input to the boiler in a certain time. It is determined that appropriate water supply control cannot be performed due to an abnormality such as being in progress, and the occurrence of the abnormality is notified.

  The determination value for determining abnormality in water level detection from the difference between the calculated water supply amount and the measured water supply amount is an arbitrary value in 10 to 50% of the calculated water supply amount, and the determination value can be changed. Since the clogging of the communication pipe 3 is gradually progressing and the amount of carry-over is also gradually increasing, if the judgment value is set to a small value, an abnormality in water level detection is detected at an early stage. be able to. However, if the determination value is too small, it may be determined that the water level detection is abnormal even if it is due to factors other than abnormality such as measurement errors. Conversely, when the determination value is increased, an abnormality occurrence output can be performed only when the abnormality has surely occurred. However, if the determination value is too large, the time for damaging the boiler becomes longer. For this reason, about 10 to 50% of the calculated water supply amount is appropriate as the judgment value. Whether the abnormality is detected at an early stage or at the stage where the abnormality is definitely occurring depends on the shape of the boiler, etc. Adjust by changing the judgment value accordingly.

  In addition, in the figure of the Example, although the heat-transfer part 1 is heated with the heating means 4, the waste heat boiler etc. which heat with the exhaust gas heat of an engine may be sufficient. In the case of an exhaust gas boiler, the control device 6 calculates the amount of water supply by detecting the amount of heat input from the exhaust gas supply amount instead of detecting the combustion state by the heating means 4. Further, the water supply amount measuring device does not have to be the flow meter 10, but may be another device as long as it measures the water supply amount. Others can be changed without departing from the scope of the present invention.

Boiler water level explanatory diagram at the water supply start water level when water level detection is normal Illustration of boiler water level at water supply stop level when water level detection is normal Boiler water level explanatory diagram at the water supply start water level when water level detection is abnormal Explanatory diagram of water level in boiler at water supply stop water level when water level detection is abnormal

Explanation of symbols

1 Heat transfer section
2 Water level detection tube
3 communication pipe
4 Heating means
5 Water supply pump
6 Control device
7 Blocking part
8 Water pipe
9 Steam separator 10 Flow meter

Claims (2)

A boiler that heats can water by heating a heat transfer section composed of a water pipe, etc., and a water level detection cylinder connected to the heat transfer section by a connecting pipe is provided. In a boiler that controls water supply based on the water level in the detection cylinder, a heat input measurement device that measures the heat input to the boiler at a predetermined time, and a water supply measurement that measures the water supply to the boiler at the same time An apparatus is installed, and the amount of heat input to the boiler and the amount of water supplied to the boiler are measured and compared.If the ratio between the amount of heat input to the boiler and the amount of water supplied to the boiler is outside the specified range, The boiler which determines the abnormality of the water level detection characterized by providing the abnormality determination apparatus which determines.   In the boiler for determining an abnormality in water level detection according to claim 1, a calculated water supply amount is calculated from a heat input amount to the boiler, and the calculated water supply amount and a measured water supply amount measured by a water supply amount measuring device The water level detection abnormality is determined by determining an abnormality when the difference is larger than a determination value determined between 10% and 50% of the calculated water supply amount. boiler.

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