JP2017049871A - Gas alarm unit and gas alarming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas alarm unit and a gas alarming method, which make alarms less irritating.SOLUTION: A surge velocity ΔV1 associated with rise velocity ΔV of gas concentration is set together with a surge alarm clear level WC2 which is set to be higher than an alarm clear level WC1. When a rise velocity of gas concentration is determined to be no less than the surge velocity, the alarm is turned off when the gas concentration comes down to the surge alarm clear level, which is higher than the alarm clear level, or less, thereby allowing the alarm to be turned off early when a high gas concentration value is caused by a transient rise, and mitigating discomfort caused by a long lasting alarm.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a gas alarm device and a gas alarm method provided with a sensor, an alarm means, and a control means.

  In general, in gas alarms, when the gas concentration of the target gas exceeds the alarm value, an alarm is generated to stop the use of the gas or encourage ventilation, and when the gas concentration falls below the alarm release value To stop the alarm. In such a gas alarm device, if the alarm value and the alarm release value are set to the same value, when the gas concentration fluctuates before and after the alarm value, the alarm is repeatedly generated and stopped, which makes the user uncomfortable. There is a possibility of giving a fault or suspecting a failure.

  Therefore, a gas alarm device has been proposed in which an alarm release value for stopping an alarm is set lower than an alarm value for generating an alarm (see, for example, Patent Document 1). In such a gas alarm device, the alarm is stopped when the gas concentration fluctuates around the alarm value by stopping the alarm when the gas concentration falls below the alarm value and falls below the alarm release value. Is difficult to repeat.

JP-A-9-210938

  By the way, in the gas alarm device that uses propane gas as a target gas, not only propane gas due to gas leakage, but also detection gas for checking whether the gas alarm generates an alarm, sealed gas of spray, etc. are detected. And generate an alarm. The increase in the gas concentration caused by these inspection gas and sealed gas is a temporary increase, and it is not necessary to continue the alarm for a long time. However, if the alarm release value is set lower than the alarm value as in the prior art, the time until the gas concentration drops below the alarm release value becomes longer, which may cause discomfort to the user.

  An object of the present invention is to provide a gas alarm device and a gas alarm method that can reduce discomfort caused by an alarm.

  In order to solve the problems and achieve the object, the invention described in claim 1 is a sensor capable of measuring a gas concentration of a target gas, an alarm means capable of generating an alarm, and the gas concentration is equal to or higher than an alarm value. Control means for causing the alarm means to generate an alarm when it is determined that the gas concentration is lower than an alarm release value lower than the alarm value and stopping the alarm when the gas concentration falls below the alarm release value. When the means determines that the gas concentration increase rate is equal to or higher than a predetermined rapid increase rate, the means determines that the gas concentration is in a rapid increase state, and the gas concentration is less than the rapid increase alarm cancellation value higher than the alarm cancellation value. The gas alarm device is characterized in that the alarm is stopped even when the temperature falls to the point.

  According to a second aspect of the present invention, in the first aspect of the present invention, when the control unit measures the gas concentration equal to or higher than the alarm value over the first fixed period, the gas concentration Is determined to be greater than or equal to the alarm value.

  According to a third aspect of the present invention, in the second aspect of the present invention, the control means is before the first fixed period elapses after the sensor measures the gas concentration equal to or higher than the alarm value. However, it is possible to determine that the rising speed is equal to or higher than the sudden rising speed.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects of the present invention, the control means includes a difference between the rising start point and the rising end point of the gas concentration, and the rising start. The rising speed is calculated based on the elapsed time from the point to the rising end point.

  The invention described in claim 5 measures the gas concentration of the target gas, generates an alarm when it is determined that the gas concentration is equal to or higher than the alarm value, and cancels the alarm when the gas concentration is lower than the alarm value. The alarm is stopped when the gas concentration falls below a value, and when it is determined that the gas concentration increase rate is equal to or higher than a predetermined rapid increase rate, it is determined that the gas concentration is in a rapid increase state, and the gas concentration is The gas alarm method is characterized in that the alarm is stopped even when it falls below a sudden rise alarm cancellation value higher than the alarm cancellation value.

  According to the first and fifth aspects of the present invention, when it is determined that the gas concentration increase rate is equal to or higher than the predetermined rapid increase rate, it is determined that the gas concentration is in a rapid increase state, and the gas concentration is the alarm release value. By stopping the alarm when it falls below the higher rise alarm release value, it is possible to detect a temporary gas concentration increase due to inspection gas or sealed gas and stop the alarm quickly, and the alarm is longer The discomfort caused by continuing can be reduced.

  According to the invention described in claim 2, when the sensor measures the gas concentration equal to or higher than the alarm value over the first fixed period, it is determined that the gas concentration is equal to or higher than the alarm value. It is possible to suppress erroneous determination that the gas concentration is equal to or higher than the alarm value when a measurement value equal to or higher than the alarm value is obtained instantaneously.

  According to the third aspect of the present invention, since it is possible to determine that the gas concentration increase rate is equal to or higher than the rapid increase rate even before the first fixed period, the gas is discharged within the first fixed period. Even when the rising rate of the concentration measurement value becomes equal to or higher than the rapid increase rate and then decreases to less than the rapid increase rate, it can be determined that the gas concentration is in the rapid increase state. That is, even when the gas concentration increases in a short time due to the transient gas, the alarm can be stopped with the rapid increase alarm release value.

  According to the fourth aspect of the present invention, based on the difference between the rising start point and the rising end point of the gas concentration, that is, the difference between the gas concentration at the start of the increase and the gas concentration at the end of the increase. By calculating the gas concentration rising speed, the measured value is slightly more noise between the rising start point and the rising end point than when the rising speed is calculated based on the instantaneous fluctuation of the gas concentration. Even if this occurs, the rising speed can be calculated with high accuracy.

It is a block diagram which shows the gas alarm device which concerns on embodiment of this invention. It is a graph which shows each setting value in the gas alarm device of FIG. It is a flowchart which shows the procedure of the alarm determination process which the gas alarm device of FIG. 1 performs. It is a flowchart which shows the procedure of the alarm decision process in the alarm determination process of FIG. It is a flowchart which shows the procedure of the rapid rise confirmation process in the alarm determination process of FIG. It is a flowchart which shows the procedure of the alarm cancellation | release process which the gas alarm device of FIG. 1 performs. It is a flowchart which shows the procedure of the alarm cancellation confirmation process in the alarm cancellation process of FIG. It is a graph which shows an example of the time change of the gas concentration which the gas alarm device of FIG. 1 detects. It is a graph which shows the other example of the time change of the gas concentration which the gas alarm device of FIG. 1 detects. It is a graph which shows the other example of the time change of the gas concentration which the gas alarm device of FIG. 1 detects. It is a graph which shows the other example of the time change of the gas concentration which the gas alarm device of FIG. 1 detects.

  Hereinafter, each embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the gas alarm device 1 of the present embodiment includes a sensor 2 that can measure the gas concentration of the target gas, an alarm unit 3 that can generate an alarm, and a control unit 4 that controls the alarm unit 3. And attached to a gas meter for propane gas, for example.

  The sensor 2 is, for example, a contact combustion type gas sensor that detects a gas concentration of propane gas as a target gas by measuring a neutral point potential difference in a bridge circuit having a detection element and a comparison element. The neutral point potential difference when the target gas is not present is the air base AB, and the neutral point potential difference increases as the gas concentration of the target gas increases. That is, the neutral point potential difference becomes an index of gas concentration, and various set values such as an alarm value and an alarm release value described later are set for the neutral point potential difference. The sensor 2 is controlled to repeat measurement at a predetermined time interval (for example, 100 msec). In addition, the sensor 2 is not limited to a contact combustion type | system | group, What is necessary is just an appropriate system according to the kind of object gas.

  The alarm means 3 is, for example, a speaker, and generates an alarm by reproducing a buzzer sound or a sound prompting ventilation. The alarm means 3 is not limited to a speaker, and may be a display device that displays an alarm on a screen, or may have both a speaker and a display device.

  The control means 4 is, for example, a microcomputer CPU provided in the gas alarm device 1. The microcomputer has storage means for storing various set values such as an alarm value and an alarm release value. Further, the control means 4 is configured to calculate the gas concentration increase rate from the measured value of the sensor 2. Specifically, the immediately preceding measurement value is subtracted from the measurement value at a certain time point, and this value is divided by the measurement time interval to obtain the gas concentration increase rate at that time point.

  Next, examples of various set values in the gas alarm device 1 will be described. As shown in FIG. 2, the alarm value W1 for causing the alarm means 3 to generate an alarm is set higher by 291 mV than the air base AB. Further, the alarm cancellation value WC1 for stopping the alarm is set lower by 58 mV than the alarm value W1. Further, the sudden rise alarm cancellation value WC2 is set to a value equal to the alarm value W1. Further, the rapid increase speed ΔV1 for determining whether the gas concentration is in a rapid increase state is set to 170 mV / sec.

  Hereinafter, an example of the alarm confirmation process and the alarm release process executed by the control unit 4 will be described with reference to the flowcharts of FIGS.

  After the main power of the gas alarm device 1 is turned on and a stabilization time necessary for the measurement value of the sensor 2 to stabilize has elapsed, the control means 4 starts the alarm determination process shown in FIG. It is repeatedly determined whether or not 100 msec has elapsed (S110). When 100 msec has elapsed (Y in S110), the control means 4 causes the sensor 2 to measure the neutral point potential difference V (S120), and starts the alarm determination process shown in FIG. 4 (S130). In the alarm confirmation process, the control means 4 determines whether or not the neutral point potential difference V measured in S120 is greater than or equal to the alarm value W1 (S210). When the neutral point potential difference V is less than the alarm value W1 (N in S210), the control means 4 ends the alarm determination process. On the other hand, if the neutral point potential difference V is greater than or equal to the alarm value W1 (Y in S210), it is determined whether or not the neutral point potential difference V is equal to or greater than the alarm value W1 for 10 consecutive times (S220). When the number of consecutive times when the neutral point potential difference V is equal to or greater than the alarm value W1 is less than 10 (N in S220), the control means 4 ends the alarm determination process. On the other hand, when the neutral point potential difference V becomes equal to or higher than the alarm value W1 for 10 consecutive times (Y in S220), the control means 4 finalizes the alarm and generates an alarm in the alarm means 3 (S230). The process ends.

  In the alarm determination process as described above, the control means 4 detects the gas when the sensor 2 measures the neutral point potential difference V greater than or equal to the alarm value W1 over the first determination period (10 measurements, 900 msec). It is configured to determine that the concentration is equal to or higher than an alarm value and generate an alarm.

  When the alarm confirmation process is completed, the control means 4 returns to the alarm determination process again, and executes the rapid rise confirmation process shown in FIG. 5 (S140). In the sudden rise confirmation process, the control means 4 first determines whether or not a sudden rise alarm has been confirmed (that is, whether or not a sudden rise state has been reached) (S310). If the sudden rise alarm has not been finalized (N in S310), the control means 4 determines whether or not the rise start point potential difference Vs indicating the gas concentration at the rise start point (when the gas concentration starts to rise) has been acquired. Determine (S320). When the increase start point potential difference Vs has not been acquired (N in S320), the control unit 4 determines whether or not the difference ΔV between the neutral point potential difference V measured in S120 and the previous measured value is greater than 0 ( S330). When the difference ΔV with respect to the previous measured value of the neutral point potential difference V is larger than 0 (Y in S330), the control means 4 makes the difference ΔV with respect to the previous measured value of the neutral point potential difference V three times in succession. Is also determined (S340). When the difference ΔV with respect to the previous measured value of the neutral point potential difference V for three consecutive times becomes larger than 0 (Y in S340), the control means 4 acquires the rising start point potential difference Vs and also calculates the elapsed time T. Measurement is started (S350), and the rapid rise confirmation process is terminated.

  At this time, even if the neutral point potential difference V is less than the alarm value W1, the rising start point potential difference Vs is acquired, and this time point can be determined as the rising start point. Further, in this embodiment, if the difference ΔV between the neutral point potential difference V and the previous measurement value is greater than 0 for three consecutive times, that is, if the neutral point potential difference V increases over 200 msec, the gas concentration increases. Is determined to have started. On the other hand, when the difference ΔV with respect to the previous measured value of the neutral point potential difference V is 0 or less (N in S330), and the number of consecutive times when the difference ΔV with respect to the previous measured value of the neutral point potential difference V is greater than 0. Is less than 3 times (N in S340), the control means 4 ends the rapid rise confirmation process.

  On the other hand, when the rise start point potential difference Vs has been acquired (Y in S320), the control means 4 determines whether or not the difference ΔV between the neutral point potential difference V and the previous measured value is 0 or less (S360). . When the difference ΔV with respect to the previous measured value of the neutral point potential difference V is 0 or less (Y in S360), the control means 4 makes the difference ΔV with respect to the previous measured value of the neutral point potential difference V three times in succession. It is determined whether or not (S370). When the difference ΔV from the previous measurement value of the neutral point potential difference V for three consecutive times becomes 0 or less (Y in S370), the control means 4 determines whether or not the neutral point potential difference V is the alarm value W1 or more. Is determined (S380). When the neutral point potential difference V is equal to or greater than the alarm value W1 (Y in S380), the control unit 4 acquires the rising end point potential difference Ve indicating the gas concentration at the rising end point (when the gas concentration has finished rising). At the same time, the measurement of the elapsed time T is terminated (S390). Next, the control means 4 calculates the rising speed ΔVT by dividing the difference between the rising end point potential difference Ve and the rising start point potential difference Vs by the elapsed time T (S400), and the rising speed ΔVT is equal to or higher than the sudden rising speed ΔV1. It is determined whether or not (S410).

  If the increase rate ΔVT is equal to or higher than the rapid increase rate ΔV1 (Y in S410), the control unit 4 determines that the gas concentration is in a rapid increase state, determines a rapid increase warning (S420), and ends the rapid increase determination process. On the other hand, when the difference ΔV from the previous measured value of the neutral point potential difference V is larger than 0 (N in S360), and the number of consecutive times that the difference ΔV from the previous measured value of the neutral point potential difference V becomes 0 or less. Is less than 3 times (N in S370), the control means 4 ends the rapid increase confirmation process. Further, when the neutral point potential difference V is less than the alarm value W1 (N in S380), and when the ascending speed ΔVT is less than the sudden ascending speed ΔV1 (N in S410), the control means 4 acquires the acquired ascending start point potential difference. Vs is discarded and the state before acquisition is obtained, and the measurement of the elapsed time T is stopped (reset) (S430), and the rapid increase confirmation process is terminated.

  On the other hand, when the rapid increase confirmation process has been confirmed (Y in S310), the control means 4 determines whether or not the neutral point potential difference V is greater than or equal to the alarm value W1 (S440). If the neutral point potential difference V is greater than or equal to the alarm value W1 (Y in S440), the control means 4 ends the rapid rise confirmation process. When the neutral point potential difference V is less than the alarm value W1 (N in S440), the control means 4 cancels the sudden rise alarm so that the sudden rise alarm has not been finalized (S450), and ends the sudden rise confirmation process.

  When the sudden rise alarm process is completed, the control means 4 returns to the alarm determination process and determines whether or not the alarm has been determined (S150). If the alarm has not been finalized (N in S150), the control means 4 returns to S110 again. On the other hand, when the alarm has been confirmed (Y in S150), the control means 4 ends the alarm determination process.

  When the alarm determination process is completed, the control means 4 executes an alarm release process shown in FIG. In the alarm release process, the control means 4 repeatedly determines whether 100 msec has elapsed (S510). When 100 msec has elapsed (Y in S510), the control unit 4 causes the sensor 2 to measure the neutral point potential difference V (S520), and starts the alarm release confirmation process shown in FIG. 7 (S530). In the alarm release confirmation process, the control means 4 determines whether or not the sudden rise alarm has been confirmed (S610). If the sudden rise alarm has been confirmed (Y in S610), the control means 4 determines whether or not the neutral point potential difference V measured in S520 is equal to or less than the sudden rise alarm release value WC2 (S620). When the neutral point potential difference V is equal to or less than the sudden rise alarm release value WC2 (Y in S620), it is determined whether or not the neutral point potential difference V is equal to or less than the sudden rise alarm release value WC2 for 10 consecutive times (S630). When the neutral point potential difference V becomes 10 or less consecutively, the control means 4 cancels the alarm, stops the alarm means 3 (S640), and ends the alarm cancellation confirmation process. When the neutral point potential difference V is larger than the sudden rise alarm release value WC2 (N in S620), and when the number of consecutive times when the neutral point potential difference V becomes equal to or less than the sudden rise alarm release value WC2 is less than 10 (N in S630). The control means 4 ends the alarm release confirmation process.

  On the other hand, when the sudden rise alarm is not finalized (N in S610), the control means 4 determines whether or not the neutral point potential difference V measured in S520 is equal to or less than the alarm cancellation value WC1 (S650). When the neutral point potential difference V is equal to or less than the alarm cancellation value WC1 (Y in S650), it is determined whether or not the neutral point potential difference V is equal to or less than the alarm cancellation value WC1 for 10 consecutive times (S660). When the neutral point potential difference V becomes 10 or less consecutively the alarm release value WC1 or less (Y in S660), the control means 4 releases the alarm and stops the alarm means 3 (S670), and the alarm release confirmation process Exit. Control is performed when the neutral point potential difference V is larger than the alarm cancellation value WC1 (N in S650), and when the number of consecutive times that the neutral point potential difference V is equal to or less than the alarm cancellation value WC1 is less than 10 (N in S660). The means 4 ends the alarm release confirmation process.

  When the alarm release confirmation process is completed, the control means 4 returns to the alarm release process and starts the sudden rise confirmation release process (S540). The sudden rise confirmation release process is substantially the same process as the sudden rise confirmation process of FIG. However, in the sudden rise confirmation release process, the neutral point potential difference V and the alarm value W1 are not compared. That is, the sudden rise confirmation release process is obtained by omitting the steps S380, S440, and S450 from the sudden rise confirmation process. If the answer is Y in S310, the process ends. If the answer is Y in S370, the process ends. The process proceeds to S390.

  When the rapid increase confirmation release process is completed, the control means 4 returns to the alarm release process and determines whether or not the alarm has been released (S550). If the alarm has not been released (N in S550), the control means 4 returns to S510. On the other hand, when the alarm has been canceled (Y in S550), the control means 4 cancels the sudden rise alarm (S560) and ends the alarm cancellation processing.

  The control means 4 starts the alarm determination process again after completing the alarm release process. That is, the alarm confirmation process and the alarm release process are executed alternately.

  Here, as shown in FIGS. 8 to 11, a plurality of changes in the gas concentration over time are exemplified, and the generation and stop of the alarm in each is described.

  First, when the gas concentration changes with time as shown in FIG. 8, the difference ΔV between the neutral point potential difference V and the previous measured value becomes greater than 0 for three consecutive times (A1), and the rise start point potential difference in the sudden rise confirmation process. Obtain Vs. Further, an alarm is generated when the neutral point potential difference V becomes equal to or higher than the alarm value W1 for 10 consecutive times (A2). That is, an alarm is generated when 900 msec has elapsed since the neutral point potential difference V becomes equal to or greater than the alarm value W1. Thereafter, when the gas concentration decreases and the difference ΔV with respect to the previous measured value of the neutral point potential difference V becomes 0 or less for three consecutive times (A3), the rising end point potential difference Ve is acquired in the sudden rise confirmation release processing. The time elapsed from A1 to A3 is the elapsed time T, and in the curve indicating the time change of the neutral point potential difference V, the slope of the straight line passing through the point corresponding to A1 and the point corresponding to A3 becomes the rising speed ΔVT. . In the example of FIG. 8, the ascending speed ΔVT is equal to or higher than the ascending speed ΔV <b> 1, and the abrupt rising alarm is confirmed. The alarm is stopped when the gas concentration decreases and the neutral point potential difference V becomes equal to or less than the sudden rise alarm release value WC2 (A4). That is, the alarm is stopped when 900 msec has elapsed since the neutral point potential difference V becomes equal to or less than the sudden rise alarm cancellation value WC2.

  Further, as shown in FIG. 9, the difference ΔV between the neutral point potential difference V and the previous measured value is continued three times before the neutral point potential difference V reaches the alarm value W1 or more for 10 consecutive times (A7). When the increase rate ΔVT is equal to or greater than the rapid increase rate ΔV1, the increase end point potential difference Ve is acquired in the rapid increase determination process, and the rapid increase alarm is determined.

  On the other hand, as shown in FIG. 10, when the neutral point potential difference V does not become the alarm value W1 or more continuously for 10 times (9 times in FIG. 10) and the increase speed ΔVT becomes the rapid increase speed ΔV1 or more, an alarm is issued in the alarm confirmation process. Is not confirmed and no alarm is generated. Further, although the sudden rise warning is confirmed in S420 of the sudden rise confirmation process, the sudden rise warning is canceled in S450 when the neutral point potential difference V becomes less than the warning value W1 (after A11).

  In addition, as shown in FIG. 11, when the neutral point potential difference V is 10 times or more continuously and becomes the alarm value W1 or more (A11) and the ascending speed ΔVT is less than the ascending speed ΔV1, the suddenly rising alarm is not fixed, The alarm is stopped when the sex point potential difference V becomes equal to or lower than the alarm release value WC1 for 10 consecutive times (A15).

  According to this embodiment, there are the following effects. That is, if it is determined that the gas concentration increase rate is higher than the rapid increase rate, the alarm is stopped when the gas concentration falls below the rapid increase alarm release value that is higher than the alarm release value. Thus, when the gas concentration becomes a high value, the alarm can be stopped quickly, and the discomfort caused by the alarm being continued for a long time can be reduced.

  Further, since the sudden rise alarm cancellation value WC2 is equal to the alarm value W1, the alarm can be stopped after the gas concentration is sufficiently lowered.

  Further, when the sensor 2 measures the neutral point potential difference V greater than or equal to the alarm value W1 over the first determination period or more, it is determined that the gas concentration is equal to or greater than the alarm value, so that the alarm value is instantaneously caused by noise or the like. When the neutral point potential difference V equal to or greater than W1 is obtained, it is possible to suppress erroneous determination that the gas concentration is greater than or equal to the alarm value.

  Further, by calculating the rising speed ΔVT based on the rising start point potential difference Vs and the rising end point potential difference Ve, the rising start point is compared with the configuration in which the rising speed is calculated based on the instantaneous fluctuation of the gas concentration. The rising speed ΔVT can be accurately calculated even if some noise occurs in the measured value of the neutral point potential difference V between the rising point and the rising end point.

  In addition, this invention is not limited to the said embodiment, Including other structures etc. which can achieve the objective of this invention, the deformation | transformation etc. which are shown below are also contained in this invention.

  For example, in the above-described embodiment, the sudden rise warning cancellation value WC2 is set equal to the warning value W1, but the sudden rise warning cancellation value only needs to be higher than the warning cancellation value WC1, and may be higher than the warning value. However, it may be low. If the rapid rise alarm release value is set high, the alarm can be stopped quickly, and if the rapid rise alarm release value is set low, it can be determined that the gas concentration has sufficiently decreased.

  In the above embodiment, an alarm is generated when the neutral point potential difference V is equal to or greater than the alarm value W1 for 10 consecutive times (900 msec). However, the number of measurements and measurement of the sensor 2 used for this determination are not limited. The interval and the total period may be set arbitrarily.

  Moreover, in the said embodiment, when the difference (DELTA) V with respect to the last measured value of the neutral point potential difference V becomes larger than 0 for 3 times continuously, it determines with a raise start point, and the time when it becomes 0 or less for 3 times continuously However, it is sufficient that the number of continuous times and the period are arbitrarily set.

  In the above embodiment, the rising speed ΔVT is calculated based on the rising start point potential difference Vs, the rising end point potential difference Ve, and the elapsed time T. However, instead of the rising end point potential difference Ve, the rising speed is increased. A neutral point potential difference at an appropriate time after the start may be used, and a time elapsed from the rising start point to this time may be used instead of the elapsed time. For example, the voltage at the time when the neutral point potential difference V becomes equal to or higher than the alarm point W1 for three consecutive times may be used, or the difference ΔV with respect to the previous measured value of the neutral point potential difference V becomes moderate (for example, 3 You may use the voltage at the time of being 1.7 mV / s or less continuously.

  Further, a rapid increase rate may be set for the instantaneous increase rate of the neutral point potential difference V. That is, when the difference ΔV between the neutral point potential difference V and the previous measurement value is continuously increased several times (for example, three times) or more than the rapid increase rate, it may be determined that the state is a rapid increase state. According to such a configuration, it is not necessary to wait for a decrease in gas concentration, and a rapidly rising state can be determined in a short period of time.

  In addition, the best configuration, method and the like for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations. Therefore, the description limiting the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such is included in this invention.

DESCRIPTION OF SYMBOLS 1 Gas alarm device 2 Sensor 3 Alarm means 4 Control means W1 Alarm value (DELTA) V1 Rapid increase speed WC1 Alarm release value WC2 Rapid increase alarm release value

Claims (5)

A sensor capable of measuring the gas concentration of the target gas;
An alarm means capable of generating an alarm; and
Control means for causing the alarm means to generate an alarm when it is determined that the gas concentration is equal to or higher than an alarm value, and for stopping the alarm when the gas concentration falls below an alarm release value lower than the alarm value. And comprising
When the control means determines that the gas concentration increase rate is equal to or higher than a predetermined rapid increase rate, the control unit determines that the gas concentration is in a rapid increase state, and cancels the rapid increase alarm when the gas concentration is higher than the alarm release value. A gas alarm device, wherein the alarm is stopped even when the value falls below a value.   The control means determines that the gas concentration is equal to or higher than the alarm value when the sensor measures a gas concentration equal to or higher than the alarm value over a first fixed period. The gas alarm described.   The control means can determine that the ascending speed is equal to or higher than the sudden rising speed even after the first determination period has elapsed after the sensor has measured a gas concentration equal to or higher than the alarm value. The gas alarm device according to claim 2.   The control means calculates the rising speed based on a difference between the rising start point and the rising end point of the gas concentration and an elapsed time from the rising start point to the rising end point. The gas alarm device according to any one of claims 1 to 3. Measure the gas concentration of the target gas,
Generating an alarm when it is determined that the gas concentration is equal to or higher than an alarm value, and stopping the alarm when the gas concentration falls below an alarm release value lower than the alarm value;
When it is determined that the gas concentration increase rate is equal to or higher than a predetermined rapid increase rate, it is determined that the gas concentration is in a rapid increase state, and the gas concentration has decreased to a rapid increase alarm release value that is higher than the alarm release value or less. The gas alarm method is characterized in that the alarm is also stopped.

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