JPS63289435A - Tube leak monitor system of boiler - Google Patents

Abstract

PURPOSE:To monitor the abnormality of a tube leak monitor and to detect the abnormality of each soot blower, by detecting the noise signal when a plurality of soot blowers are normal and the noise signal at the time of judgement to compare both of them. CONSTITUTION:When each soot blower is normally operated, each soot blower is operated by a tube leak monitor 1 and the signal sound thereof is stored in a reference noise signal memory means 3 as a reference noise signal along with the data specifying the operated soot blower from a soot blower control apparatus 2. Next, the signal from each soot blower at the time of judge operation is measured as a judge noise signal at every soot blower in the same way as the case of a reference noise signal, and the reference noise signal is compared with the judge noise signal at every soot blower by a comparing means 4 and, from the comparing result, an abnormal soot blower is judged by a judge means 5. Further, when all of the soot blowers show the same abnormal value as the comparing result, the abnormality of the monitor 1 is judged by the judge means 5 and, on the basis of the same abnormal value, a sensitivity characteristic correction means 6 corrects the sensitivity of the monitor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tube leak monitor for diagnosing the health of heat exchanger tubes constituting a boiler.

[Conventional technology]

Conventional boiler tube leak equipment consists of a sensor, an amplifier, a signal conditioner that processes the signal detected by the sensor, etc. Multiple sensors are placed around the boiler furnace to quickly prevent water and steam leakage from heat transfer tubes. I'm trying to detect it. The principle of detecting tube leaks is to issue an alarm indicating that a leak has occurred when the level of the detection signal exceeds a certain threshold.

[Problem that the invention seeks to solve]

In this case, the problem is the acoustic noise generated from the soot blower device that blows soot from the boiler tubes (because air or steam is injected to clean the heat transfer tubes, the sound from the heat transfer tubes is generated when steam leaks). This effect is very similar to the acoustic noise generated), and in addition to eliminating this effect, in order to increase detection sensitivity, it is necessary to use a device with extremely high temporal stability as a signal conditioner that makes up the device. Therefore, the alarm setting value needs to be about 10% or less of the full scale.

In addition, when trying to estimate the location of a leakage point based on the strength and weakness of signals from multiple sensors (this concept exists, but nothing has been commercialized to date), The operator can only determine the location of the leak based on the sensor that detected the noise signal first or the loudest noise signal.

One of the reasons for this is that the sensitivity of the noise detection circuit consisting of the sensor, preamplifier, and signal conditioner needs to be very stable over time (for example, below one decimal place), which makes it very expensive. It was not practical to use, and there was no method provided to check whether the sensitivity was correct during operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tube leak monitor system that can monitor abnormalities in a tube leak monitor by utilizing the noise emitted by the soot blower, which has been harmful to tube leak monitors in the past, and can also detect abnormalities in each soot blower. be.

[Means for solving problems]

The above problem includes a plurality of soot blowers for cleaning the boiler furnace inner tube, a control device for the soot blower, and a sensor for detecting leakage of the boiler furnace inner tube, and the sensor is configured to detect the soot blowing sound of the soot blower. In a boiler tube leak monitoring system comprising a tube leak monitor disposed in a tube leak monitor, a reference noise signal of each of the soot blowers during a reference operation measured by the tube leak monitor is inputted, and each of the soot blowers is identified. a reference noise signal storage means for inputting information from the control device and storing each of the reference noise signals in correspondence with each of the specified information; each of the soot blowers during a judgment operation measured by the tube leak monitor; a comparison in which the determination noise signals corresponding to each soot blower are inputted, information specifying each soot blower is inputted from the control device, the determination noise signal corresponding to each soot blower is compared with the reference noise signal, and the comparison result is stored. means; determining means for determining an abnormality in each soot blower based on the comparison result of each soot blower; and/or further having the determining means determine an abnormality in the tube leak monitor based on the comparison result; The problem is solved by adding a sensitivity characteristic modifying means for outputting modification information and modifying the sensitivity characteristics of the tube monitor using the modification information.

[Effect]

Next, the operation will be explained with reference to FIG. 1, which is a diagram corresponding to claim 1, and FIG. 2, which is a diagram corresponding to claim 2.

As shown in FIG. 1, when each stove blower is operating normally, the tube leak monitor 1 operates each soot blower and uses the signal sound as a reference noise signal to identify the operating soot blower from the soot blower control device 2. The information is stored in the reference noise signal storage means 3 together with the information, and then the signal from each soot blower during the judgment operation is measured as a judgment noise signal for each soot blower in the same way as the reference noise signal, and the reference noise signal and judgment noise signal are A comparison means 4 compares the soot blowers for each soot blower, and a determination means 5 determines an abnormal soot blower based on the comparison result.

Furthermore, as shown in FIG. 2, when the above comparison results show that all of the soot blowers have the same abnormal value, the determining means 5 determines that the tube leak monitor 1 is abnormal, and based on the same abnormal value. A sensitivity characteristic modification means 6 modifies the sensitivity of the tube leak monitor 1.

〔Example〕

FIG. 3 shows a circuit configuration diagram as an embodiment of the present invention. In the figure, a sensor 8, a preamplifier 9, a signal conditioner 10, a leak alarm setting device 11, a leak alarm 12
is constructed in the prior art, and the self-compensating device 7 in the figure shows the circuit of the present invention.

A gain correction circuit 6 that corrects the sensitivity based on the noise signal level of the soot blower device detected in this device, and a signal integration circuit 7-2 that calculates the temporal average value of the noise signal.
, a signal storage circuit 3 that stores this calculation result 7-3 in association with the soot blower device, and a circuit 4 that performs calculation using the stored reference signal level 7-4 and the above calculation result 7-3.
, a comparator circuit 5 that compares the calculation amount cuff-5 and outputs the result, a signal 7-9 that changes the gain depending on the comparison result, and a signal 7-6 that displays a soot blower abnormality alarm.

Signals 7-8 from the soot blower control device 2 mean operating signals for the soot blower installed near the sensor, and these operating signals are used to automatically or manually control the soot blower depending on the operation of the boiler. It operates as soon as it is driven. Note that due to the characteristics of soot blower devices, two or more devices are not operated at the same time, and one device at a time is operated one after another. In this example, a case is described in which there are four soot blower devices in the vicinity related to the sensor.

FIG. 4 shows a functional diagram of the gain correction circuit 6. Since the gain correction signal 7-9 is intermittently updated as the soot blower device operates, a signal storage circuit 6-2 is provided to store the intermediate signal level, and a gain change command 5-9 is provided. The gain correction signal 7-9 transmitted at that time is stored in response to the storage command 6-3 generated in synchronization with the gain correction signal 7-9. As will be described later, the gain correction signal 7-9 indicates the ratio to the reference signal level 7-4, so in order to correct this ratio to 1.0, the reciprocal of this is obtained by the signal inverter 6-1 and the original is applied to the signal 10-1. In this way, sensitivity changes caused by the detection circuits of the sensor, preamplifier, and signal conditioner are corrected. Gain correction signal 7-
We will explain how to find 9.

FIG. 5 shows a functional diagram of the signal integration circuit.

The purpose of this circuit is to accurately (including reproducibility) measure the noise signal level when the soot blower is in operation.
For example, the signal from the relay 2-2 is integrated by the integrator 3-1 for a certain period of time (until the timer 2-1 operates) (X1 contact 0N) to obtain the acoustic noise signal, but the integration time is kept constant ( By using the contact point Y), we are looking for a kind of time average. Another method is the integrator 3
It is also effective to use a peak hold circuit instead of -1 to find the maximum value during a certain period of time.

In this way, the signal level for the next calculation is obtained, and the signal calculation end signal Z2-3 in FIG.
The turning off of timer T2-1 is used as a subsequent calculation start command (for example, memory retention command 3-2 in Fig. 6), but the purpose is to control the acoustic signal level of the soot blower device. The purpose of this is to display that the calculation has been completed.

FIG. 6 shows a functional diagram of the circuit for creating the reference signal level 7-4.

The storage permission command 3-3 is basically operated by an operator or the like at the start of boiler operation (ONL until the soot blower device is operated for one or more cycles).

It is explained that the soot blower device functions to sequentially record acoustic noise signals in the related signal storage device 3-1 according to the operation of the soot blower device (for example, according to X□ to X4). The storage start is executed from the time when the storage holding command 3-2 is issued, but its original purpose is to provide a timing signal indicating that the calculation of the acoustic noise signal has been completed as described above.

FIG. 7 shows a circuit that calculates the rate of change between the standard signal level 7-4 calculated at the start of boiler operation as described above and the acoustic signal level 7-3 obtained during the current operation of the soot blower device. . That is, the ratio between the standard signal level 3-1 (for example, Xl) of the soot blower device and the current acoustic signal level is calculated by the dividing circuit 4-1, and the result is stored in the storage circuit 4-1.
Store in 2. (Note that the storage operation is started by the storage hold command 3-2 indicating that the calculation of the acoustic signal level has been completed as described above, but this is an operation for synchronizing the timing as described above.) Eighth. The figure shows a circuit that compares the signal changes obtained as described above.The purpose is to detect changes in the sensitivity of the sensor, preamplifier, and signal conditioner detection circuits when all signals change to the same degree. Correct the loop gain (Figure 4), and if there is only a partial change, it is determined that the soot blower device is abnormal rather than the sensitivity of the tube leak monitor, and the received acoustic signal level has changed. Sends a soot blower equipment abnormality alarm. In FIG. 8, the addition calculator 5-1 calculates the changes in the four acoustic signal levels 7-
A function generator 5-3 which calculates the average value of 5, compares this value with each sound level 7-5, calculates the difference between the two, and sends an output only when the difference is small. Therefore, the fact that there is an output from this function generator (for example, "1") means that the difference between the overall average value and a certain sound level (7-5) is small; 7-5) shows the same tendency as the signal of 7-5). Conversely, no output (for example, "0") indicates that the signal is different from a certain sound level (7-5). The tendency of the signal change can be determined by determining the result of adding the output signals (1 or 0) obtained as described above by the adder 5-4 using the signal comparator b-5 based on the magnitude of the addition result. I can do it. In other words, if the total value is 4, all the signals (in this case, 4 signals) are changing with the same tendency, so the sensitivity of the detection circuit should be corrected, which means 5-6.
turns on and transmits the output of the addition calculator 5-1 to the gain correction circuit 6. If the total value is 3 or less, the soot blower device is said to be abnormal and an alarm 7-6 is issued. The set value of the function generator 5-3 and the set value of the signal comparator 5-5 should be set to appropriate values according to the boiler condition, and should be set to a constant value or made to be a variable depending on the boiler condition. varies depending on the conditions of the applied plant.

[Other Examples]

Another embodiment of the invention is shown in FIG. This embodiment relates to a method for creating the standard signal level 7-4. In the method shown in Fig. 6, the standard signal level is created once at the start of boiler operation, but when calculating the signal at each timing, the previous The signal is intended to be used as a reference signal. That is, the calculation is completed and the soot blower device (for example, X
The sound signal level 4-3 used for calculation is transferred to the reference signal holding circuit 3-1 by the signal that the operation of 1) is stopped (Xl is turned OFF), and is intended to be used for the next calculation. .

Note that the above description has been made in terms of circuit functions, so the circuit configuration (hardware) can also be realized as an analog circuit or a software circuit built into a computer.

[Effects of the Invention] According to the present invention, an abnormal soot blower can be determined by detecting and comparing the normal noise signal and the determination noise signal of a plurality of soot blowers with a tube leak monitor.
Furthermore, when the comparison value of the above two signals changes in common with each soot blower, it can be determined that the sensitivity characteristics of the tube leak monitor are abnormal and the sensitivity characteristics can be corrected, which was previously harmful to tube leak monitors. This has the excellent effect of making it possible to monitor abnormalities in the tube leak monitor by using the noise emitted by the soot blower, and also to detect abnormalities in each soot blower.

[Brief explanation of drawings]

1 is a claim correspondence diagram for claim 1, 2 is a claim correspondence diagram for claim 2, FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. 4 is a claim correspondence diagram for claim 1. FIG. 5 is a diagram showing a specific example of the gain correction circuit in FIG. 3; FIG. 5 is a diagram showing a specific example of the signal integration circuit in FIG. 3;
6 shows a specific example of the signal storage circuit in FIG. 3, FIG. 7 shows a specific example of the arithmetic circuit in FIG. 3, and FIG. 8 shows a specific example of the comparison circuit in FIG. 3. 9 are diagrams showing specific examples of circuits according to other embodiments of the present invention. DESCRIPTION OF SYMBOLS 1... Tube leak monitor, 2... Soot blower control device, 3... Reference noise signal storage means, 4... Comparison means, 5... Judgment means, 6... Sensitivity characteristic correction means.

Claims (2)

[Claims] (1) It has a plurality of soot blowers for cleaning the boiler furnace inner tube, a control device for the soot blower, and a sensor for detecting leakage of the boiler furnace inner tube, and the sensor is capable of detecting the soot blowing sound of the soot blower. In a boiler tube leak monitoring system comprising a tube leak monitor arranged in the boiler, a reference noise signal of each of the soot blowers during a reference operation measured by the tube leak monitor is inputted, and information identifying each of the soot blowers is inputted. a reference noise signal storage means for inputting the reference noise signal from the control device and storing each of the reference noise signals corresponding to each of the identifying information; Comparing means for inputting each determination noise signal, inputting information specifying each soot blower from the control device, comparing the determination noise signal corresponding to each soot blower with the reference noise signal, and storing the comparison result. A tube leak monitoring system for a boiler, comprising: a determining means for determining abnormality of each soot blower based on the comparison result of each soot blower. (2) It has a plurality of soot blowers for cleaning the boiler furnace inner tube, a control device for the soot blower, and a sensor for detecting leakage of the boiler furnace inner tube, and the sensor is capable of detecting soot blowing sound of the soot blower. In a boiler tube leak monitoring system comprising a tube leak monitor arranged in the boiler, a reference noise signal of each of the soot blowers during a reference operation measured by the tube leak monitor is inputted, and information identifying each of the soot blowers is inputted. a reference noise signal storage means for inputting the reference noise signal from the control device and storing each of the reference noise signals corresponding to each of the identifying information; Comparing means for inputting each determination noise signal, inputting information specifying each soot blower from the control device, comparing the determination noise signal corresponding to each soot blower with the reference noise signal, and storing the comparison result. and; determining means for determining an abnormality in each soot blower and determining an abnormality in the tube leak monitor based on the comparison result of each of the soot blowers, and outputting correction information in the case of an abnormality; and determining the sensitivity of the tube leak monitor based on the correction information. A boiler tube leak monitoring system comprising: a sensitivity characteristic correction means for correcting characteristics;