JP4488134B2 - Alarm signal processing method for droplet detection sensor - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a droplet detection sensor that quickly detects the generation of minute droplets caused by condensation of water vapor, high-temperature gas, chemical gas, etc., particularly when the droplet volume exceeds a certain level. The present invention relates to an alarm signal processing method for issuing a message.
[0002]
[Prior art]
As a means for quickly detecting dew condensation such as water vapor, high temperature gas or chemical gas, “Droplet Detection Method and Droplet Detection Sensor” (Japanese Patent Laid-Open No. 11-325827) has already been invented, and as a system incorporating this, There is a variable thermoelectric gas turbine system. This thermoelectric variable type gas turbine system generates steam using combustion exhaust gas of a gas turbine as a heat source, and injects a part of this steam into a combustor, thereby increasing the output of the gas turbine and improving thermal efficiency. It is. Gas turbines that inject steam include a chain cycle that injects steam as heated steam by a heater, and a partially regenerated gas turbine that mixes saturated steam with high-temperature air to bring it into a heated state.
[0003]
The droplet detection sensor attached to this thermoelectric variable type gas turbine system detects whether steam is injected into the combustor, in particular, whether water droplets are generated, and the thermoelectric variable type gas turbine system is detected based on the detection signal. An emergency stop can be obtained. As described above, the droplet detection sensor is for solving the problem of the gas turbine due to the mist in the steam.
[0004]
FIGS. 7A, 7B, and 7C are explanatory diagrams of the detection principle by the droplet detection sensor.
The droplet detection sensor 1 detects adhesion of droplets using the following phenomenon. That is, if the ground glass-like glass surface 3 of the sensor tip 2 is in contact with the gas body, the light L transmitted through the glass body of the sensor tip 2 is totally reflected by the glass surface 3. (A). At this time, the amount of reflected light R received by the light receiving element serving as the detection member is small and the output voltage of the light receiving element is also small.
[0005]
On the other hand, when a droplet adheres to the glass surface 3 or a liquid film is formed, the irradiation light L repeats refraction and reflection on the droplet surface (b) and (c). At this time, the amount of reflected light R received by the light receiving element increases, and the output voltage of the light receiving element increases. In this way, the change in the amount of the reflected light R received by the light receiving element is used as a change in the output signal to detect the adhesion of the droplet.
[0006]
[Problems to be solved by the invention]
In the conventional droplet detection sensor described above, the change in the amount of the reflected light R received by the light receiving element is output as a DC output signal, which is recorded by a data recorder or the like. That is, in the thermoelectric variable gas turbine plant, the output of the droplet detection sensor is recorded on the data recorder together with the generator output of the gas turbine, the process steam amount, the gas turbine injection steam amount, the nozzle steam injection amount, etc. The plant manager monitored and used it to grasp the operation status of the plant.
[0007]
However, the DC output signal of the droplet detection sensor is an analog signal in the range of 0 to 5 V, for example, and other outputs such as generator output, process steam amount, gas turbine injection steam amount, nozzle steam injection amount, etc. In comparison, the output change is so severe that there is a problem that it is difficult for a skilled person to instantaneously determine the state of occurrence of droplets.
[0008]
For this reason, it is difficult to determine the occurrence status of the droplet in real time from the output of the droplet detection sensor, and even if the droplet detection sensor detects an abnormal carryover or the like, it cannot be instantaneously determined in real time. As a result, the emergency stop of the gas turbine plant was delayed, and there was a risk of burning the gas turbine parts. The situation was difficult to judge from output signals other than the droplet detection sensor.
[0009]
The present invention has been made to solve such problems. That is, the object of the present invention is to determine the occurrence state of a droplet in real time from the output of the droplet detection sensor, and to detect this in real time when the occurrence state of the droplet is abnormal due to abnormal carryover or the like. An object of the present invention is to provide an alarm signal processing method for a droplet detection sensor that can detect instantaneously and output a necessary alarm output.
[0010]
[Means for Solving the Problems]
According to the present invention, the transparent detection body (4) having irregularities formed on the droplet detection surface (3), and the light emitting element (12) that transmits the light through the transparency detection body and irradiates the liquid surface detection surface. ), A light receiving element (14) that receives the reflected light, and an amplifying circuit (16) that amplifies the DC output voltage of the light receiving element.
An alarm signal extraction step (A) for setting a threshold value for alarm of the DC output voltage and setting the component of the DC output voltage exceeding the alarm threshold value as an analog voltage for alarm;
Waveform shaping step of shaping said alarm analog voltage into a pulse signal by a predetermined threshold value (B), and
There is provided an abnormality detection step (C) for detecting abnormality of droplet generation based on the frequency of generation of the pulse signal, and a warning signal processing method for a droplet detection sensor is provided.
[0011]
According to a preferred embodiment of the present invention, the DC output voltage is AD converted and displayed.
[0012]
According to the method of the present invention, since the DC output voltage of the droplet detection sensor is AD-converted and displayed, even if the output change of the droplet detection sensor is severe compared to other outputs, The administrator can grasp the occurrence state of the droplets relatively easily.
[0013]
Further, only the component of the DC output voltage exceeding the alarm threshold set in advance in the alarm signal extraction step (A) is extracted, and this is shaped into a pulse signal in the waveform shaping step (B), and the abnormality detection step In (C), since the abnormality of droplet generation is detected based on the frequency of generation of pulse signals, the detected abnormality can be displayed to the plant manager by an alarm alarm or an alarm lamp. As a result, even if you are not an expert, you can determine the occurrence status of droplets in real time from the output of the droplet detection sensor, and if the occurrence status of droplets is abnormal due to abnormal carryover, etc. It is possible to detect immediately and perform the necessary processing .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to a common member and the overlapping description is abbreviate | omitted.
[0015]
FIG. 1 is an overall configuration diagram of a droplet detection sensor used in an alarm signal processing method of the present invention. As shown in this figure, the droplet detection sensor 1 includes a transparency detector 4 having irregularities formed on the droplet detection surface 3, and transmits the light to the liquid level detection surface 3 through the transparency detector 4. The light emitting element 12 to irradiate, the light receiving element 14 which receives the reflected light, and the amplifier circuit 16 which amplifies the DC output voltage of the light receiving element 14 are provided.
[0016]
In other words, the droplet detection sensor 1 includes a sensor tip 2 having a glass surface 3 (droplet detection surface) as a surface on which a ground glass-like uneven surface is formed. The droplet detection sensor 1 is formed in the pipe 5 with the sensor tip 2 attached to the step 8 of the protective cylinder 7 that can be fitted and attached to the cylindrical sensor attachment 6 formed on the pipe 5. It is designed to be flush with the wall surface. A lid 10 is attached to the sensor distal end 2 in the protective cylinder 7 via a pressing ring 9 that fixes the sensor distal end 2. The lid 10 is attached to a cover 11 that closes the sensor attachment portion 6 of the pipe 5, and the sensor tip 2 can be easily attached to the sensor attachment portion 6 by attaching the cover 11.
[0017]
In addition, when the droplet detection sensor 1 is in a state where the glass surface 3 of the sensor tip 2 is in contact with the gas body, the light irradiated through the glass body of the sensor tip 2 is irradiated on the glass surface 3 (detection surface). ) On the other hand, when a droplet or liquid film adheres to the glass surface 3, the refraction and reflection on the droplet surface are repeated, and the reflected light is received to cause the droplet to adhere to the output signal. To detect.
[0018]
Furthermore, in order to irradiate the glass surface 3 of the sensor front-end | tip part 2 of the droplet detection sensor 1 with the light L for droplet detection, the light emitting element 12 is installed in a remote position as a light emitting member. A light-emitting optical fiber 13 (light introducing portion) for guiding light from the light-emitting element 12 is attached so as to pass through the cover 11 and the lid 10 and face the back surface of the droplet detection sensor 1.
[0019]
On the other hand, a light receiving element 14 for detecting a change in the amount of reflected light R reflected from the glass surface 3 (detection surface) of the sensor tip 2 is also provided at a remote position. Similarly, the reflected light R is guided to the light receiving element 14 through the light receiving optical fiber 15 (light receiving portion) attached so as to pass through the cover 11 and the lid body 10 and face the back surface of the droplet detection sensor 1. is there. An output signal from the light receiving element 14 is amplified by an amplifier circuit 16. Further, a fixing frame 17 for fixing the light emitting optical fiber 13 and the light receiving optical fiber 15 is attached to the outside of the cover 11, and the two optical fibers 13 and 15 are attached in a predetermined direction. However, it is also possible to adopt a structure in which the optical fibers 13 and 15 (light introducing part, light receiving part) are not interposed between the light emitting element 12 and the light receiving element 14.
[0020]
The droplet detection sensor 1 configured as described above is attached to the sensor attachment portion 6 formed in the middle of the pipe 5 such as a combustor for each cover 11 so that the sensor tip 2 of the droplet detection sensor 1 is connected to the pipe 5. To be flush with the inner wall.
[0021]
In addition, in place of the ground glass-like glass surface 3 of the sensor tip 2, irregularities are formed on the glass surface 3, light can be transmitted, and the amount of reflected light can be reduced when the droplet is attached and when it is dry. As long as it changes, other materials such as a synthetic resin material may be used instead of the glass material, and the material can be appropriately selected according to the temperature of the gas body flowing in the pipe 5.
[0022]
2 to 4 are output examples of the above-described droplet detection sensor. FIG. 2 shows when the turbine plant is started, FIG. 3 shows normal operation, and FIG. In each figure, the horizontal axis represents time, and the vertical axis represents the generator output of the gas turbine, the process steam amount, the gas turbine injection steam amount, the nozzle steam injection amount, and the output of the droplet detection sensor.
[0023]
As apparent from FIG. 2, at the time of start-up, all of the generator output, the process steam amount, the gas turbine injection steam amount, the nozzle steam injection amount, and the output of the droplet detection sensor change slowly. Therefore, these can be monitored by the plant manager and the operation status of the plant can be easily grasped.
[0024]
Further, during the normal operation of FIG. 3, all the fluctuations of each output become large. In particular, since the output of the droplet detection sensor fluctuates violently, it becomes difficult to grasp the operation state of the plant from these. I understand that.
[0025]
Furthermore, when the abnormality shown in FIG. 4 occurs, all of the generator output, the process steam amount, the gas turbine injection steam amount, the nozzle steam injection amount, and the output of the droplet detection sensor fluctuate violently. Is abnormally intense, and it is very difficult for a skilled person to immediately determine the occurrence of droplets.
[0026]
FIG. 5 is a control block diagram showing the alarm signal processing method of the present invention. FIG. 6 is a schematic diagram showing a processing signal by the alarm signal processing of FIG. As shown in FIG. 6, the method of the present invention comprises three steps: an alarm signal extraction step (A), a waveform shaping step (B), and an abnormality detection step (C).
[0027]
In the alarm signal extraction step (A), an alarm threshold 19 for the DC output voltage 18 (0 to 5 V) from the amplifying circuit 16 is set in advance , and the DC output exceeds the alarm threshold 19. The voltage component is output as the alarm analog voltage 20. FIG. 6A shows the DC output voltage 18 in part A of FIG. 5, and FIG. 6B shows the alarm analog voltage 20 when the alarm threshold 19 is set to 3.25 V, for example. Yes. As is apparent from FIG. 6B, only the DC output voltage component exceeding the alarm threshold value 19 can be extracted and used by this step.
[0028]
As shown in FIG. 5, the DC output voltage 18 (0 to 5 V) is preferably output in parallel for output to a customer line or recording with a data recorder or the like. In parallel, the DC output voltage is preferably AD converted and displayed so that the plant manager or the like can monitor it in real time. With this display , even if the output change of the droplet detection sensor is severe compared to other outputs, the plant manager can grasp the occurrence of droplets relatively easily from this display.
[0029]
In FIG. 5, in the waveform shaping step (B), the alarm analog voltage 20 is shaped into a pulse signal 21 by a predetermined threshold value. This threshold value is set slightly higher than the alarm threshold value 19. The voltage level of the shaped pulse signal can be set regardless of the DC output voltage, and is set to 0 to 1 V, for example. FIG. 6B shows the shaped pulse signal.
[0030]
Further, in the abnormality detection step (C), an abnormality of droplet generation is detected based on the frequency of generation of the pulse signal. In this detection, the pulse signal is counted by the pulse counter, and if the count within a certain time exceeds the set number set in advance, it is judged as abnormal, and the necessary alarm alarm or warning lamp is turned on to manage the plant. To the user.
For example, by setting the abnormality detection level to 5 times in 5 minutes, the abnormality in the example of FIG. 4 can be reliably detected.
[0031]
As described above, according to the method of the present invention, only the component of the DC output voltage that exceeds the alarm threshold set in advance in the alarm signal extraction step (A) is extracted, and this is performed in the waveform shaping step (B). Is detected in the abnormality detection step (C), and the abnormality of the droplet generation is detected based on the frequency of generation of the pulse signal. Therefore, the detected abnormality can be displayed to the plant manager by an alarm alarm or an alarm lamp. As a result, even if you are not an expert, you can determine the occurrence status of droplets in real time from the output of the droplet detection sensor, and if the occurrence status of droplets is abnormal due to abnormal carryover, etc. It is possible to detect immediately and perform the necessary processing .
[0032]
In addition, this invention is not limited to embodiment mentioned above, Of course, unless it deviates from the summary of this invention, it can change variously.
[0033]
【The invention's effect】
As described above, the alarm signal processing method for a droplet detection sensor according to the present invention can determine the occurrence state of a droplet in real time from the output of the droplet detection sensor, and can generate a droplet due to abnormal carryover or the like. If the situation is abnormal, this can be detected instantaneously in real time, and a necessary alarm output can be output.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a droplet detection sensor used in an alarm signal processing method of the present invention.
FIG. 2 is an output example of a droplet detection sensor when a turbine plant is started.
FIG. 3 is an output example of a droplet detection sensor during normal operation of the turbine plant.
FIG. 4 is an output example of a droplet detection sensor when an abnormality occurs in a turbine plant.
FIG. 5 is a control block diagram showing an alarm signal processing method of the present invention.
FIG. 6 is a diagram showing a processing signal according to the alarm signal processing method of the present invention.
FIG. 7 is an explanatory diagram of a detection principle of a droplet detection sensor.
[Explanation of symbols]
L irradiation light, R reflected light,
1 droplet detection sensor, 2 sensor tip,
3 glass surface (droplet detection surface), 4 transparency detector,
5 Piping, 6 Sensor mounting part, 7 Protective cylinder,
8 steps, 9 holding rings, 10 lids, 11 covers,
12 light emitting elements, 13 optical fibers for light emission (light introduction part),
14 light receiving element, 15 light receiving optical fiber (light receiving part),
16 amplifier circuit, 17 fixed frame, 18 DC output voltage,
19 alarm threshold, 20 alarm analog voltage,
21 Pulse signal

Claims (2)

Transparency detector (4) having concavities and convexities formed on the droplet detection surface (3), a light emitting element (12) that transmits the transparency detector and irradiates light on the liquid surface detection surface, and its reflected light An alarm signal processing method for a droplet detection sensor, comprising: a light receiving element (14) that receives light; and an amplification circuit (16) that amplifies a DC output voltage of the light receiving element,
An alarm signal extraction step (A) for setting a threshold value for alarm of the DC output voltage and setting the component of the DC output voltage exceeding the alarm threshold value as an analog voltage for alarm;
Waveform shaping step of shaping said alarm analog voltage into a pulse signal by a predetermined threshold value (B), and
An abnormality detection step (C) for detecting abnormality of droplet generation based on the frequency of generation of the pulse signal, and a warning signal processing method for a droplet detection sensor. The alarm signal processing method for a droplet detection sensor according to claim 1, wherein the DC output voltage is AD-converted and displayed.

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