JP6446772B2 - Gas alarm - Google Patents

Description

  The present invention relates to a gas alarm device that can easily check a gas detection function.

  In general, it is checked whether or not the gas alarm operates normally immediately after the start of use of the gas alarm or after a certain period of use. Workers at a gas sales company conduct inspections when installing gas alarms at home. In addition, in the inspection work after a certain period of use, the inspection worker goes to the installation site of the gas alarm to perform the inspection.

  This inspection is performed by spraying a main detection gas (hereinafter simply referred to as the main detection gas) as an actual detection target to the gas sensor of the gas alarm device, or by preparing an inspection gas prepared for inspection (hereinafter simply referred to as the inspection gas). ) Or the like to check whether an alarm sound is generated. When an alarm sound is emitted, the gas alarm device has sensitivity to gas and is judged to have a normal function.

Here, the main detection gas and the inspection gas are the following gases.
The main detection gas of the gas alarm device is a fuel gas that is city gas (main component is methane gas) and carbon monoxide (CO) gas that is generated during incomplete combustion of the fuel gas. Since fuel gas and carbon monoxide gas have different properties, two types of gas detection elements corresponding to each of them are usually used.
In the present specification, the following description will be made assuming that only methane is detected as the main detection gas in order to simplify the description.

The inspection gas of the gas alarm device ignites a stove of city gas and uses the burned gas. Such inspection gases for city gas are methane, hydrogen, and carbon monoxide (CO). Further, the gas lighter is ignited and the burned gas is used. Such inspection gases for city gas are butane, hydrogen, and carbon monoxide (CO).
In the present specification, for simplification of description, it will be described below that methane, hydrogen, and carbon monoxide (CO) are detected as inspection gases.

  As a prior art of a gas alarm device having such an inspection function, for example, one described in Patent Document 1 (Japanese Patent Laid-Open No. 2008-269533) is known. In this prior art, the inspection mode is set to 4 minutes immediately after the power is turned on. During the inspection mode, an alarm is given when the ratio of gas detection to the previous time exceeds the second threshold.

  As another prior art of a gas alarm having an inspection function, for example, one described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2004-38660) is known. In this prior art, methane gas is detected by this detection, but hydrogen gas is detected by inspection detection. In view of this, when detecting a gas in a single pulse energization, inspection detection is performed for inspection gas different from the main detection gas at a timing different from the main detection timing for the main detection gas.

JP 2008-269533 A JP 2004-38660 A

  In the gas alarm using the commercial power source of the cited reference 1, since the inspection is performed after the power is turned on, it is necessary to turn off the power once and then turn on the power again in order to perform the inspection by blowing the gas after the installation. there were. However, the power plug of the gas alarm is often away from the gas alarm, and the power cord is difficult to plug in and out, such as using the outlet behind the refrigerator.

  In Cited Document 2, a battery-driven gas alarm is provided with a switch for switching between main detection and inspection, and switching is easy. However, a configuration that is not used many times a year is a cost increase factor. . There is also a problem of unnecessary power consumption such as energizing the switch to monitor on / off of the switch, and there is a circumstance that it is desired to delete such a switch.

  Therefore, the present invention has been made in view of the above problems, and its object is to make it easy to switch between the normal monitoring mode and the inspection mode without increasing the cost. An object of the present invention is to provide a gas alarm device that reduces the amount of gas.

In order to achieve the above object, the invention according to claim 1 is directed to a heater having a temperature at which the inspection gas or the main detection gas is detected, and a sensor in response to the inspection gas or the main detection gas while being heated by the heater. A gas sensor having a gas sensing unit with a variable resistance value;
An alarm unit for outputting an alarm;
An alarm stop switch to stop the alarm output;
A control circuit to which the heater, the gas detection unit, the alarm unit, and the alarm stop switch are connected, and controls to perform detection in a normal monitoring mode for detecting the detected gas and detection in an inspection mode for detecting the inspection gas. And
With
The control circuit unit is
A predetermined operation of the alarm stop switch causes a transition from the normal monitoring mode to the inspection mode, and then a transition to the normal monitoring mode when a predetermined inspection time elapses, and pulse energization that repeats the heater at a predetermined cycle. Has the function to perform this detection and inspection by
In the normal monitoring mode to detect this detection gas,
A main detection heater driving means for driving the heater over a main detection heater driving time so that the gas detection unit reaches a main detection gas detection temperature, and the gas detection unit after the main detection heater driving time has elapsed from the start of the main detection heater driving. The detection sensor resistance value acquisition means for obtaining the detection sensor resistance value and the detection gas detection means for determining that the detection gas is detected when the detection sensor resistance value is lower than the detection alarm level, It functions repeatedly with a predetermined main detection heater drive cycle, and
During the inspection mode to detect inspection gas,
Inspection heater driving means for driving the heater over an inspection heater driving time longer than the main detection heater driving time so that the gas detection unit reaches the inspection gas detection temperature, and the passage of the inspection heater driving time from the start of the inspection heater driving The inspection sensor resistance value acquisition means for obtaining the inspection sensor resistance value of the gas sensing unit later, and the inspection gas detection means for determining that the inspection gas is detected when the inspection sensor resistance value is lower than the inspection alarm level, It is characterized by repeatedly functioning in the inspection heater driving cycle.

請 Motomeko according to a second aspect of the present invention, the gas detector according to claim 1, check the warning level of the inspection mode, characterized in that the lower than normal monitoring mode of the detection alarm level.

The invention according to claim 3
A gas sensor comprising: a heater having a temperature at which the inspection gas or the main detection gas is detected; and a gas detection unit that changes a sensor resistance value in response to the inspection gas or the main detection gas while being heated by the heater;
An alarm unit for outputting an alarm;
An alarm stop switch to stop the alarm output;
A control circuit to which the heater, the gas detection unit, the alarm unit, and the alarm stop switch are connected, and controls to perform detection in a normal monitoring mode for detecting the detected gas and detection in an inspection mode for detecting the inspection gas. And
With
The control circuit unit is
A predetermined operation of the alarm stop switch causes a transition from the normal monitoring mode to the inspection mode, and then a transition to the normal monitoring mode when a predetermined inspection time elapses, and pulse energization that repeats the heater at a predetermined cycle. Has the function to perform this detection and inspection by
In the normal monitoring mode to detect this detection gas,
A main detection heater driving means for driving the heater over a main detection heater driving time so that the gas detection unit reaches a main detection gas detection temperature, and the gas detection unit after the main detection heater driving time has elapsed from the start of the main detection heater driving. The detection sensor resistance value acquisition means for obtaining the detection sensor resistance value and the detection gas detection means for determining that the detection gas is detected when the detection sensor resistance value is lower than the detection alarm level, It functions repeatedly with a predetermined main detection heater drive cycle, and
During the inspection mode to detect inspection gas,
Inspection heater driving means for driving the heater over an inspection heater driving time longer than the main detection heater driving time so that the gas sensing unit reaches an inspection gas detection temperature, and a predetermined inspection waiting time has elapsed since the start of the inspection heater driving A first inspection sensor resistance value acquisition means for obtaining a first inspection sensor resistance value of the gas sensing unit later, and a first inspection gas detected when the first inspection sensor resistance value is lower than the first inspection alarm level; First inspection gas detection means for determining the second inspection sensor resistance value acquisition means for obtaining the second inspection sensor resistance value of the gas sensing section after the inspection heater driving time from the start of inspection heater driving, and second inspection sensor resistance As a second inspection gas detection means for determining that the second inspection gas is detected when the value is lower than the second inspection alarm level, it is repeated at a predetermined inspection heater driving cycle. Characterized in that it function.

The invention according to 請 Motomeko 4,
A gas sensor comprising: a heater having a temperature at which the inspection gas or the main detection gas is detected; and a gas detection unit that changes a sensor resistance value in response to the inspection gas or the main detection gas while being heated by the heater;
An alarm unit for outputting an alarm;
An alarm stop switch to stop the alarm output;
A control circuit to which the heater, the gas detection unit, the alarm unit, and the alarm stop switch are connected, and controls to perform detection in a normal monitoring mode for detecting the detected gas and detection in an inspection mode for detecting the inspection gas. And
With
The control circuit unit is
A predetermined operation of the alarm stop switch causes a transition from the normal monitoring mode to the inspection mode, and then a transition to the normal monitoring mode when a predetermined inspection time elapses, and pulse energization that repeats the heater at a predetermined cycle. Has the function to perform this detection and inspection by
In the normal monitoring mode to detect this detection gas,
A main detection heater driving means for driving the heater over a main detection heater driving time so that the gas detection unit reaches a main detection gas detection temperature, and the gas detection unit after the main detection heater driving time has elapsed from the start of the main detection heater driving. The detection sensor resistance value acquisition means for obtaining the detection sensor resistance value and the detection gas detection means for determining that the detection gas is detected when the detection sensor resistance value is lower than the detection alarm level, It functions repeatedly with a predetermined main detection heater drive cycle, and
During the inspection mode to detect inspection gas,
Inspection heater driving means for driving the heater over an inspection heater driving time so that the gas detection unit reaches an inspection gas detection temperature, and a first inspection of the gas detection unit after a predetermined inspection waiting time has elapsed from the start of the inspection heater driving. First inspection sensor resistance value acquisition means for obtaining a sensor resistance value, and first inspection gas detection means for determining that the first inspection gas is sensed when the first inspection sensor resistance value is lower than the first inspection alarm level. And second inspection sensor resistance value acquisition means for obtaining a second inspection sensor resistance value of the gas sensing unit after the inspection heater driving time from the start of the inspection heater driving, and the second inspection sensor resistance value is lower than the second inspection alarm level. As the second inspection gas detection means for determining that the second inspection gas has been detected when it is low, it functions repeatedly with a predetermined inspection heater driving cycle,
The inspection mode first inspection warning level and a second inspection warning level when is characterized by low Ikoto than the detection warning level of the normal monitoring mode.

The invention according to 請 Motomeko 5, in the gas alarm device according to any one of claims 1 to 4, a predetermined operation of the alarm stop switch, continuously longer than a preset time It is a pressing operation .

The invention according to 請 Motomeko 6 is the gas detector according to any one of claims 1 to 5, check the heater driving cycle of the heater driving of the inspection mode, the normal monitoring mode the heater than the sensing heater driving cycle of the driving and said short Ikoto.

The invention according to 請 Motomeko 7 is the gas detector according to any one of claims 1 to 6, the delay time until the alarm from the alarm start of the inspection mode, an alarm in the normal monitoring mode It is characterized by being shorter than the delay time from the start to the alarm .

  ADVANTAGE OF THE INVENTION According to this invention, the gas alarm which reduces the labor of inspection work can be provided by enabling switching with normal monitoring mode and inspection mode easily, without raising cost.

It is a block diagram of a gas alarm device. It is a relationship diagram of sensor resistance value-gas concentration. It is a flowchart figure of the normal monitoring mode of a control circuit part. It is a flowchart figure of the inspection mode of a control circuit part. FIG. 5A is an explanatory diagram of heater driving in a normal monitoring mode, and FIG. 5B is an explanatory diagram of heater driving in an inspection mode. FIG. 6A is an explanatory diagram of heater driving in another monitoring mode, FIG. 6A is an explanatory diagram of heater driving in a normal monitoring mode, and FIG. 6B is an explanatory diagram of heater driving in an inspection mode. FIG. 7A is an explanatory diagram of heater driving in a normal monitoring mode, and FIG. 7B is an explanatory diagram of heater driving in an inspection mode. FIG. 8A is an explanatory diagram of heater driving in a normal monitoring mode, and FIG. 8B is an explanatory diagram of heater driving in an inspection mode. FIG. 9A is an explanatory diagram of heater driving in another mode, FIG. 9A is an explanatory diagram of heater driving in a normal monitoring mode, and FIG. 9B is an explanatory diagram of heater driving in an inspection mode. FIG. 10A is an explanatory diagram of heater driving in a normal monitoring mode, and FIG. 10B is an explanatory diagram of heater driving in an inspection mode. It is a flowchart figure of other inspection modes of a control circuit part. FIG. 12A is an explanatory diagram of heater driving in another heater mode, FIG. 12A is an explanatory diagram of heater driving in a normal monitoring mode, and FIG. 12B is an explanatory diagram of heater driving in an inspection mode. FIG. 13A is an explanatory diagram of heater driving in a normal monitoring mode, and FIG. 13B is an explanatory diagram of heater driving in an inspection mode. FIG. 14A is an explanatory diagram of heater driving in the normal monitoring mode, and FIG. 14B is an explanatory diagram of heater driving in the inspection mode. FIG. 15A is an explanatory diagram of heater driving in a normal monitoring mode, and FIG. 15B is an explanatory diagram of heater driving in an inspection mode.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a gas alarm. The gas alarm device 10 is a gas leak alarm device that detects a combustible gas such as city gas leaked from a gas appliance or gas pipe and issues an alarm. This gas alarm device may employ AC 100 V as its power source, or may employ a battery.

  Such a gas alarm device 10 includes a gas sensor 11, a control circuit unit 12, an alarm unit 13, an alarm stop switch 14, a power supply unit 15, a power supply circuit unit 16, a constant voltage circuit unit 17, and the like, and further has a load resistance R, The illustrated circuit includes a shunt resistor R2, a transistor switch SW1, a transistor switch SW2, and the like. Hereinafter, the transistor switch SW1 and the transistor switch SW2 are omitted, and are referred to as a switch SW1 and a switch SW2.

Next, the characteristics of the gas sensor will be described. FIG. 2 is a relationship diagram of sensor resistance value-gas concentration. As for gas, carbon monoxide (CO), hydrogen (H ₂ ), and methane each show a change in sensor resistance value according to a change in gas concentration. Carbon monoxide (CO), for hydrogen _{(H 2),} respectively, indicated by the dashed line. On the other hand, methane is indicated by a solid line.

As indicated by the alternate long and short dash line in the figure, with respect to carbon monoxide (CO) and hydrogen (H ₂ ), the sensor resistance value hardly changes even when the gas concentration increases. On the other hand, for methane, the sensor resistance value decreases as the gas concentration increases.

  And the gas sensor 11 is provided with the sensor resistance 11a for detecting gas concentration, and the heater resistance 11b for heating this. The sensor resistor 11a is a gas sensing unit of the present invention, and the heater resistor 11b is a heater of the present invention.

  The sensor resistance 11a has a resistance value according to the concentration of the surrounding methane gas or the like as described above, and the heater resistance 11b is set to, for example, 400 ° C. or the like in the gas leak detection process performed at a predetermined driving cycle. In this state, the sensor resistance value (such as a voltage value corresponding to the resistance value) of the sensor resistor 11a is measured by heating. This detection gas is basically city gas (methane gas). Other gases may be used, but a gas sensor corresponding to the type of the detected gas is used.

  In this example, the power supply unit 15 supplies 100 VAC power, and the power supply circuit unit 16 supplies a constant voltage of 3.3 (V) to supply power to the entire circuit shown in FIG. That is, the electric power from the power supply unit 15 is supplied to a sensor system circuit which is a gas detection means including a heater resistor 11b and a sensor resistor 11a in the gas sensor 11, a load resistor R, a shunt resistor R2, switches SW1, SW2, and the like. The control circuit unit 12 is also supplied with power from the power supply unit 15 and the power supply circuit unit 16. The power supply unit 15 may be a battery, and the power supply circuit unit 16 may use a constant voltage of 3.3 (V).

  Here, the sensor circuit includes a circuit in which a sensor resistor 11a, a load resistor R, and a switch SW2 are connected in series (first series circuit), a switch SW1, a constant voltage circuit unit 17, a heater resistor 11b, and a shunt. It consists of a circuit (second series circuit) in which a resistor R2 is connected in series. The voltage of 3.3 (V) is applied to each of these series circuits.

  Regarding the first series circuit, when the switch SW2 is ON, the voltage V1 obtained by dividing 3.3 (V) according to the resistance value of the sensor resistor 11a and the resistance value of the load resistor R is the control circuit unit. 12 is input to the illustrated input terminal AD3. The resistance value of the load resistor R may be arbitrary, but is fixed. When the resistance value of the sensor resistor 11a changes, the voltage value V1 changes. That is, the voltage value V1 indicates the resistance value of the sensor resistor 11a.

  As described above, the resistance value of the sensor resistor 11a changes according to the concentration of the surrounding methane gas, but also changes depending on the temperature when the heater resistor 11b is driven, as will be described later. In response to this change in resistance value, the input voltage value at the input terminal AD3 changes. Details will be described later.

  As for the second series circuit, an arbitrary voltage is applied to the heater resistor 11b and the like by the constant voltage circuit unit 17 with the switch SW1 being ON. A control signal is output from the output terminal OUT2 of the control circuit unit 12 to the constant voltage circuit unit 17, and the output voltage of the constant voltage circuit unit 17 is arbitrarily controlled. As the output voltage of the constant voltage circuit unit 17 changes, the temperature when the heater resistor 11b is driven changes. Conventionally, the output voltage of the constant voltage circuit unit 17 has been controlled so that the driving temperature of the heater resistor 11b is about 400 ° C. In this method, the heater drive control can be performed by lowering the output voltage of the constant voltage circuit unit 17 so that the temperature during driving of the heater resistor 11b is lower than normal (for example, at about 250 ° C.). A drive pattern for lowering the temperature at the time of this detection may be adopted.

  The control circuit unit 12 is a microcomputer (CPU or the like) that controls the operation of the gas alarm device 10 as a whole, and by executing a program stored in advance in a built-in memory (not shown), Perform gas detection processing in inspection mode.

  The control circuit unit 12 has output terminals OUT1, OUT2, OUT3, input terminals AD1, AD2, AD3, and the like. The output terminal OUT1 is connected to the base of the switch SW1, and the switch SW1 is ON / OFF controlled by an output signal from the output terminal OUT1. The output terminal OUT3 is connected to the base of the switch SW2, and the switch SW2 is ON / OFF controlled by an output signal from the output terminal OUT3. The output terminal OUT2 has already been described.

  The input terminal AD3 has already been described. The output voltage of the constant voltage circuit unit 17 is input to the input terminal AD1, and the voltage between the heater resistor 11b and the shunt resistor R2 is input to the input terminal AD2. That is, the difference between the voltages input to the input terminals AD1 and AD2 means the voltage applied to the heater resistor 11b. By controlling the output voltage of the constant voltage circuit unit 17 as described above, the voltage applied to the heater resistor 11b is controlled, thereby controlling the temperature when the heater resistor 11b is driven.

  These input terminals AD1, AD2, and AD3 include not only the input terminals but also a function (AD converter) for converting an analog signal (voltage value V1 or the like) input to the input terminals into a digital value. To do. Therefore, the control circuit unit 12 acquires a digital value of the voltage value V1 through the input terminal AD3, for example.

  Although not specifically described, the control circuit unit 12 can convert the acquired voltage value V1 into a resistance value of the sensor resistor 11a or convert it into a methane gas concentration by an existing function. is there.

  The alarm unit 13 includes an alarm sound output unit 13a, an alarm display unit 13b, and an external alarm output unit 13c. The alarm sound output unit 13a is a part that emits a sound such as an alarm sound, and includes, for example, a speaker or a buzzer. Based on the control from the control circuit unit 12, the alarm sound output unit 13a notifies the gas leak state by a voice message or an electronic sound. The alarm display unit 13b is configured by an LED (light emitting diode) or the like, and at the time of an alarm, the LED is blinked or turned on to display an alarm state with the LED to notify a gas leakage state. The external alarm output unit 13c outputs an alarm signal to an external device such as a gas meter or a central monitoring panel at the time of alarm.

  When the alarm stop switch 14 is pressed when an alarm is issued, the control circuit unit 12 receives the input signal and controls the alarm unit 13 to stop the alarm output. As will be described later, when the alarm stop switch 14 is pressed and held, the inspection mode is entered. This inspection mode will be described later.

  When the sensor is driven, the control circuit unit 12 turns on the switch SW1 and the switch SW2 by the output from the output terminals OUT1 and OUT3, so that the control circuit unit 12 includes the gas sensor 11 (the heater resistor 11b and the sensor resistor 11a), the load resistor R, and the like. The sensor system circuit is operated by supplying power.

  Basically, the control circuit unit 12 repeatedly executes a periodic operation for detecting a gas leak in the normal monitoring mode. That is, the gas detection is performed at a constant cycle T2 by driving the heater of the gas sensor 11 at the main detection heater driving time T1 and the main detection heater driving cycle T2. As an example, the gas sensor 11 is driven at a main detection heater driving time T1 = 100 ms (milliseconds) and a main detection heater driving period T2 = 45 seconds as shown in FIG. Specifically, based on control by an internal timer (not shown) of the control circuit unit 12, the following operation is executed every main detection heater drive cycle T2 = 45 seconds.

  The control circuit unit 12 turns on the switch SW1 and the switch SW2 according to the output from the output terminals OUT1 and OUT3 each time the sensor driving timing according to the main detection heater driving cycle T2 = 45 seconds is reached. A predetermined voltage is applied to the circuit and the second series circuit. The heater resistor 11 b is heated to, for example, 400 ° C. by controlling the output voltage of the constant voltage circuit unit 17. The control circuit unit 12 reads the gas sensor output voltage V1 from the AD3 terminal when 100 ms has elapsed from the sensor drive timing (that is, at the end of the detection heater drive time T1). Of course, the sensor drive ends immediately after that.

  In this way, the control circuit unit 12 detects the sensor output (voltage value V1; corresponding to the resistance value of the sensor resistor 11a) of the gas sensor 11 via the input terminal AD3. For example, the sensor output has a predetermined gas concentration (alarm reference concentration). The gas leak detection is performed by determining whether or not the threshold value corresponding to) is exceeded. The control circuit unit 12 may perform a process of converting the output voltage V1 into a gas concentration or a sensor resistance value and comparing it with a threshold value corresponding thereto.

  Next, the main detection and inspection by the control circuit unit 12 of the gas alarm device 10 configured as described above will be described. First, the main detection in the normal monitoring mode will be described. As a premise, it is assumed that the atmosphere near the gas sensor 11 is filled with the detection gas (methane gas).

  In the gas alarm device 10, when detecting this detection gas, the heater temperature of the gas sensor 11 must be about 400 ° C., and a large electric power is required. For example, in the case of battery driving, in order to be able to continuously drive the battery for 5 years, which is the expiration date of the gas alarm device 10, without replacing the battery, it is an issue to perform sensor driving with power saving. ing. For this reason, as will be described later, the main detection heater driving period of the sensor is set to be long to some extent during normal monitoring.

The control circuit unit 12 performs a series of processes for detecting the detected gas.
The control circuit unit 12 functions as main detection heater driving means for driving the heater over the main detection heater driving time T1 (100 ms) so that the gas detection unit reaches the main detection gas detection temperature (step S11 in FIG. 3). Specifically, as shown in FIG. 5A, the control circuit unit 12 starts driving to pass a current through the heater resistor 11b to increase the temperature of the heater resistor 11b.

  Subsequently, the control circuit unit 12 functions as a main detection sensor resistance value acquisition unit that acquires the main detection sensor resistance value of the gas detection unit after the main detection heater driving time T1 (100 ms) has elapsed from the start of the main detection heater drive (FIG. 3). Step S12). Specifically, the control circuit unit 12 obtains the main detection sensor resistance value from the sensor resistance 11a when 100 ms which is the main detection heater driving time T1 has elapsed from the start of driving (the black circle timing in FIG. 5A). Then, as shown in FIG. 5 (a), the control circuit unit 12 stops driving the current flowing through the heater resistor 11b to stop the detection heater (step S13 in FIG. 3).

  Subsequently, the control circuit unit 12 functions as a main detection gas detection unit that determines that the main detection gas is detected when the main detection sensor resistance value is lower than the main detection alarm level (step S14 in FIG. 3).

  When the detected gas is detected, the control circuit unit 12 drives the alarm unit 13 to give an alarm. The alarm unit 13 warns the detection of the detection gas (methane gas). Although not shown, a buzzer may be employed as the alarm sound output unit 13a so that the buzzer is sounded continuously or intermittently. Moreover, LED may be employ | adopted as the alarm display part 13b, and LED may be lighted and blinked. At this time, when the alarm stop switch 14 is pressed, the control circuit unit 12 controls to stop the alarm output.

Such main detection is always performed, and the same drive is performed after returning to step S11. And said step S11-S14 are performed after this detection heater drive period T2 (45s) progress. As a result, in the normal monitoring mode, as shown in FIG.
In this way, the detected gas can be detected in the normal monitoring mode.

  Next, inspection detection in the inspection mode will be described. First, the long press of the alarm stop switch 14 for changing to the inspection mode will be described. The alarm stop switch 14 has a function for stopping the alarm only when the alarm is issued in the normal monitoring mode. However, the alarm stop switch 14 is shifted to the inspection mode in the normal monitoring mode (when no alarm is issued). It has a function to make it.

  When the control circuit unit 12 determines that the alarm stop switch 14 has been pressed continuously for a longer time than a preset time, the control circuit unit 12 transitions from the normal monitoring mode to the inspection mode. The preset time will be described. The transition to the normal inspection mode is made at the first time of a predetermined length, and the transition to the gas blowing inspection mode is made at the second time longer than the first time.

  It does not operate if the alarm stop switch 14 is pressed for less than 1 second. If the alarm stop switch 14 is accidentally pressed for a short time, the mode is not shifted to the inspection mode.

When the pressing time of the alarm stop switch 14 is 1 second or more and less than 5 seconds, the normal inspection mode is entered. Check whether the gas alarm 10 is operating normally. For example, “normal” is reported.
When the pressing time of the alarm stop switch 14 is 5 seconds or more and less than 10 seconds, the alarm sound demonstration mode is entered. The alarm sound of the gas alarm device 10 is output. For example, it is reported that “a gas is leaking”.

  When the pressing time of the alarm stop switch 14 is 10 seconds or more, the gas spray inspection mode is entered. The operation of the gas alarm device 10 is checked by blowing gas. By using the alarm stop switch 14 in this way, it is possible to easily transition to these inspection modes. Hereinafter, a particularly important gas blowing inspection mode is simply referred to as an inspection mode.

  Now, the inspection worker performs a long press on the alarm stop switch 14 in order to shift to the inspection mode. When the control circuit unit 12 determines that the alarm stop switch 14 has been pressed for a long time continuously beyond a preset time, the control circuit unit 12 transitions from the normal monitoring mode to the inspection mode. Subsequently, the inspection worker injects inspection gas to fill the periphery of the gas sensor 11. Here, the inspection gas is hydrogen gas, carbon monoxide gas, methane gas or a mixed gas thereof.

The control circuit unit 12 performs a series of processes for detecting the inspection gas.
The control circuit unit 12 functions as inspection heater driving means for driving the heater over the inspection heater driving time T3 (100 ms) so that the gas detection unit reaches the inspection gas detection temperature (step S21 in FIG. 4). Specifically, as shown in FIG. 5B, the control circuit unit 12 starts driving to cause a current to flow through the heater resistor 11b and raises the temperature of the heater resistor 11b.

  Subsequently, the control circuit unit 12 functions as an inspection sensor resistance value acquisition unit that obtains an inspection sensor resistance value of the gas sensing unit after the inspection heater driving time T3 (100 ms) has elapsed from the start of the inspection heater driving (step S22 in FIG. 4). . Specifically, the control circuit unit 12 obtains the inspection sensor resistance value from the sensor resistance 11a when 100 ms, which is the inspection heater driving time T3, has elapsed from the start of driving (the black circle timing in FIG. 5B). Then, as shown in FIG. 5 (b), the control circuit unit 12 stops driving the current flowing through the heater resistor 11b to stop the detection heater (step S23 in FIG. 4).

  Subsequently, the control circuit unit 12 functions as inspection gas detection means for determining that inspection gas is detected when the inspection sensor resistance value is lower than the inspection alarm level (step S24 in FIG. 4).

The control circuit unit 12 drives the alarm unit 13 to give an alarm. In the inspection, if carbon monoxide (CO) or hydrogen (H ₂ ) that should be burned and removed by a catalyst layer (not shown) of the gas sensor 11 is detected, it is determined that there is an abnormality in the gas alarm device 10. Even when methane cannot be detected, it is determined that there is an abnormality in the gas alarm device 10. Which gas is detected can be determined by the inspection sensor resistance value. The alarm unit 13 warns the detection of the inspection gas. Although not shown, a buzzer may be employed as the alarm sound output unit 13a so that the buzzer is sounded continuously or intermittently. Moreover, LED may be employ | adopted as the alarm display part 13b, and LED may be lighted and blinked. And if an alarm is issued, it will be confirmed that it operates normally. At this time, when the alarm stop switch 14 is pressed, the control circuit unit 12 controls the alarm unit 13 to stop the alarm output.

Such inspection is performed until an inspection time (for example, 3 minutes) elapses. If the inspection time has not elapsed, the process returns to step S21 to perform the same driving (step S25 in FIG. 4), and the inspection heater After the drive cycle T4 (45s) has elapsed, the above steps S21 to S24 are repeated. If the inspection time has elapsed, the inspection mode is terminated and the normal monitoring mode is restored. In such an inspection mode, as shown in FIG. 5B, pulse driving is performed for a predetermined inspection time.
In this way, the inspection gas can be detected in the inspection mode.

  Note that the main detection heater drive (step 11) in FIG. 3 and the inspection heater drive (step 21) in FIG. 4 may be the same drive, the main detection heater drive time T1 (100 ms), the main detection heater drive cycle. The values of T2 (45 s), inspection heater driving time T3 (100 ms), and inspection heater driving cycle T4 (45 s) are other values (for example, main detection heater driving time T1 and inspection heater driving time T3 are set to 90 ms. Drive cycle T2 and inspection heater drive cycle T4 may be 50 s). Further, the main detection gas detection (step 14) in FIG. 3 and the inspection gas detection (step 24) in FIG. 4 may be the same alarm level, or may be different alarm levels as shown in a later embodiment.

The gas alarm device 10 of this embodiment has been described above. In this embodiment, the alarm stop switch 14 is pressed and held for a transition from the normal monitoring mode to the inspection mode, which facilitates inspection.
In addition, when the alarm stop switch is operated during an alarm such as a gas leak, this function does not operate and the alarm stop function operates. Therefore, the function of the original alarm stop switch 14 is also fulfilled. sell.
Further, by sharing with the existing alarm stop switch 14, no additional parts are required.

  Next, the second embodiment will be described. In the second embodiment, the configuration of the gas alarm device 10 of the first embodiment is used as it is, and the gas detection in the normal monitoring mode is performed in the same manner, but the inspection gas detection in the inspection mode is improved. Specifically, the main detection heater driving time T1 in the normal monitoring mode is different from the inspection heater driving time T3 in the inspection mode. That is, as shown in FIGS. 6A and 6B, the inspection heater driving time T3 in the inspection mode is shorter than the main detection heater driving time T1 in the normal monitoring mode. For example, the main detection heater driving time T1 in the normal monitoring mode is set to 100 ms, whereas the inspection heater driving time T3 in the inspection mode is set to 30 to 40 ms. This inspection is particularly suitable for detection of hydrogen gas and carbon monoxide gas, and the present inventor has found that 30 to 40 ms is sufficient for detection of hydrogen gas and carbon monoxide gas. This reduces power consumption.

The values of the main detection heater driving time T1 (100 ms), the main detection heater driving cycle T2 (45 s), the inspection heater driving time T3 (30 to 40 ms), and the inspection heater driving cycle T4 (45 s) are other values (for example, The main detection heater driving time T1 may be 90 ms, the inspection heater driving time T3 may be 20 ms, and the main detection heater driving cycle T2 and the inspection heater driving cycle T4 may be 50 s). An optimum value may be selected according to the actual condition on condition that the inspection heater driving time T3 <the main detection heater driving time T1 is satisfied.
Such a gas alarm device 10 may be used.

  Next, the third embodiment will be described. Even in the third embodiment, the configuration of the gas alarm device 10 of the first embodiment is used as it is, and the gas detection in the normal monitoring mode is performed in the same manner, but the gas detection in the inspection mode is improved. Specifically, the main detection heater driving time T1 in the normal monitoring mode is different from the inspection heater driving time T3 in the inspection mode. That is, as shown in FIGS. 7A and 7B, the inspection heater driving time T3 in the inspection mode is longer than the main detection heater driving time T1 in the normal monitoring mode. For example, the main detection heater driving time T1 in the normal monitoring mode is set to 100 ms, whereas the inspection heater driving time T3 in the inspection mode is set to 200 ms. The present inventors have found that this inspection is particularly suitable for detecting methane gas.

The values of the main detection heater driving time T1 (100 ms), the main detection heater driving cycle T2 (45 s), the inspection heater driving time T3 (200 ms), and the inspection heater driving cycle T4 (45 s) are other values (for example, main detection). The heater driving time T1 may be 90 ms, the inspection heater driving time T3 may be 250 ms, and the detection heater driving cycle T2 and the inspection heater driving cycle T4 may be 50 s). The optimum value may be selected according to the actual condition on condition that the inspection heater driving time T3> the main detection heater driving time T1 is satisfied.
Such a gas alarm device 10 may be used.

Next, the fourth embodiment will be described. In the fourth embodiment, the inspection alarm level in the inspection mode is lower than the main detection alarm level in the normal monitoring mode with respect to the gas alarm device 10 of the first, second, and third embodiments described above. It is what I did. For example, as shown in FIG. 2, the main detection alarm level of methane in the normal monitoring mode is 3000 ppm, whereas the inspection alarm level of methane in the inspection mode is 2000 ppm. If it does in this way, it will detect even if there is little fall of a sensor resistance value, and quick and reliable detection is attained. Similarly, hydrogen gas and carbon monoxide gas are reliably detected.
Such a gas alarm device 10 may be used.

  Next, the fifth embodiment will be described. In the fifth embodiment, the main detection heater driving cycle T2 of the heater drive in the normal monitoring mode and the inspection mode in addition to the gas alarm device 10 in the first, second, third, and fourth embodiments described above. The heater driving period T4 is different from the heater driving period T4. That is, those applied to the first embodiment as shown in FIGS. 8A and 8B, those applied to the second embodiment as shown in FIGS. 9A and 9B, and FIGS. 10A and 10B. As shown in FIG. 5, the heater driving inspection heater driving period T4 in the inspection mode is shorter than the main detection heater driving period T2 of heater driving in the normal monitoring mode. To do. For example, the main detection heater driving period T2 in the normal monitoring mode is 45 s, whereas the inspection heater driving period T4 in the inspection mode is 10 s. In this inspection, particularly, the inspection gas is repeatedly detected in a short time, so that it is detected quickly and reliably.

  Further, as shown in FIGS. 8A and 8B, the main detection heater driving time T1 (100 ms), the main detection heater driving cycle T2 (45 s), the inspection heater driving time T3 (100 ms), and the inspection heater driving cycle T4 ( 10s) is a value other than this (for example, the main detection heater driving time T1 and the inspection heater driving time T3 are 90 ms, the main detection heater driving period T2 is 50 s, and the inspection heater driving period T4 is 8 s). Also good. The optimum value may be selected according to the actual condition on condition that the detection heater driving cycle T2> the inspection heater driving cycle T4 is satisfied.

  Further, as shown in FIGS. 9A and 9B, the main detection heater driving time T1 (100 ms), the main detection heater driving cycle T2 (45 s), the inspection heater driving time T3 (30 to 40 ms), and the inspection heater driving cycle. The values of T4 (10 s) are other values (for example, the main detection heater driving time T1 is 90 ms, the inspection heater driving time T3 is 20 ms, the main detection heater driving cycle T2 is 50 s, and the inspection heater driving cycle T4 is 8 s. Yes). The optimum value may be selected according to the actual condition on the condition that the main detection heater driving time T1> the inspection heater driving time T3 and the main detection heater driving cycle T2> the inspection heater driving cycle T4.

Further, as shown in FIGS. 10A and 10B, the main detection heater driving time T1 (100 ms), the main detection heater driving cycle T2 (45 s), the inspection heater driving time T3 (200 ms), and the inspection heater driving cycle T4 ( 10s) is a value other than this (for example, the main detection heater driving time T1 is 90 ms, the inspection heater driving time T3 is 250 ms, the main detection heater driving period T2 is 50 s, and the inspection heater driving period T4 is 8 s). It may be. The optimum value may be selected according to the actual condition on condition that the main detection heater driving time T1 <the inspection heater driving time T3 and the main detection heater driving period T2> the inspection heater driving period T4.
Furthermore, the present invention may be applied in addition to the fourth embodiment described above.
Such a gas alarm device 10 may be used.

  Next, the sixth embodiment will be described. In the sixth embodiment, the delay time from the alarm start to the alarm in the inspection mode is normally monitored with respect to the gas alarm device 10 of the first, second, third, fourth and fifth embodiments described above. This is shorter than the delay time from alarm start to alarm in mode. It waits until a predetermined delay time elapses after the gas is detected, and if the gas is detected even after the elapse of the delay time, it is determined that the gas is detected. Since the delay time from alarm start to alarm in the normal monitoring mode is long, the alarm is detected for the first time when it is detected many times repeatedly, but false alarms are reduced because it is an error in one detection . On the other hand, in the inspection, since the delay time from the start of the alarm in the inspection mode to the alarm is shortened, an alarm is issued immediately after the detection, and the inspection ends early. In addition, it is good also as change of the repetition frequency of gas detection instead of the change of delay time. For example, in the normal inspection mode, it is determined that the detected gas has been detected ten times continuously, but in the inspection mode, it may be determined that the inspection gas has been detected three times in succession. Moreover, it is good also as an immediate alarm by making delay time zero. Such a count is also included in the change of the delay time. Such a gas alarm device 10 may be used.

  Subsequently, the seventh embodiment will be described. In the seventh embodiment, the configuration of the gas alarm device 10 of the first embodiment described above is used as it is and the gas detection in the normal monitoring mode is made the same, but the gas detection in the inspection mode is improved. Specifically, the gas is detected twice in the inspection heater driving time in the inspection mode.

  First, in order to shift to the inspection mode, the alarm stop switch 14 is long pressed. When the control circuit unit 12 determines that the alarm stop switch 14 has been pressed for a long time continuously beyond a preset time, the control circuit unit 12 transitions from the normal monitoring mode to the inspection mode. Subsequently, the inspection worker injects inspection gas to fill the periphery of the gas sensor 11. The inspection gas is hydrogen gas, carbon monoxide gas, methane gas or a mixed gas thereof.

The control circuit unit 12 performs a series of processes for detecting the inspection gas.
The control circuit unit 12 functions as inspection heater driving means for driving the heater over the inspection heater driving time T3 (100 ms) so that the gas detection unit reaches the inspection gas detection temperature (step S31 in FIG. 11). Specifically, as shown in FIG. 12B, the control circuit unit 12 starts driving to pass a current through the heater resistor 11b and raises the temperature of the heater resistor 11b.

  Subsequently, the control circuit unit 12 functions as first inspection sensor resistance value acquisition means for obtaining a first inspection sensor resistance value of the gas sensing unit after a predetermined inspection waiting time T5 (30 to 40 ms) has elapsed since the start of the inspection heater drive. (Step S32 in FIG. 11). Specifically, the control circuit unit 12 obtains the first inspection sensor resistance value from the sensor resistance 11a when 30 to 40 ms, which is the inspection standby time T5, has elapsed from the start of driving (the timing of the white circle in FIG. 12B). .

  Subsequently, the control circuit unit 12 functions as first inspection gas detection means that determines that the first inspection gas is detected when the first inspection sensor resistance value is lower than the first inspection alarm level (FIG. 11). Step S33). For example, it is assumed that hydrogen or carbon monoxide is detected.

  Subsequently, the control circuit unit 12 functions as second inspection sensor resistance value acquisition means for obtaining the second inspection sensor resistance value of the gas sensing unit after the inspection heater driving time T3 (100 ms) has elapsed from the start of the inspection heater driving (FIG. 11). Step S34). Specifically, the control circuit unit 12 obtains the inspection sensor resistance value from the sensor resistance 11a when 100 ms, which is the inspection heater driving time T3, has elapsed from the start of driving (the black circle timing in FIG. 12B). Then, as shown in FIG. 12B, the control circuit unit 12 stops driving the current flowing through the heater resistor 11b and stops the inspection heater (step S35 in FIG. 11).

  Subsequently, the control circuit unit 12 functions as a second inspection gas detection unit that determines that the second inspection gas is detected when the second inspection sensor resistance value is lower than the second inspection alarm level (FIG. 11). Step S36).

  The control circuit unit 12 drives the alarm unit 13 to give an alarm. The alarm unit 13 warns that either or both of the first and second inspection gases are detected. Although not shown, a buzzer may be employed as the alarm sound output unit 13a so that the buzzer is sounded continuously or intermittently. Moreover, LED may be employ | adopted as the alarm display part 13b, and LED may be lighted and blinked. And if an alarm is issued, it will be confirmed that it operates normally. At this time, when the alarm stop switch 14 is pressed, the control circuit unit 12 controls the alarm unit 13 to stop the alarm output.

Such inspection is performed until an inspection time (for example, 3 minutes) elapses. If the inspection time has not elapsed, the process returns to step S31 to perform the same driving (step S37 in FIG. 11), and the inspection heater After the drive cycle T4 (45s) has elapsed, the above steps S31 to S36 are repeated. If the inspection time has elapsed, the inspection mode is terminated and the normal monitoring mode is restored.
In this way, the inspection gas can be detected in the inspection mode.

The gas alarm device 10 of this embodiment has been described above. In this embodiment, the alarm stop switch 14 is pressed and held for a transition from the normal monitoring mode to the inspection mode, which facilitates inspection.
Further, when the alarm stop switch 14 is operated during an alarm such as a gas leak, this function does not operate and the alarm stop function operates, so that the original function of the alarm stop switch 14 can be achieved. .
Further, by sharing with the existing alarm stop switch 14, no additional parts are required.
In addition, the detection capability is enhanced by making it easy to detect each gas (for example, hydrogen, carbon monoxide and methane gas).

  The main detection heater drive (step 11) in FIG. 3 and the inspection heater drive (step 31) in FIG. 11 may be the same drive, the main detection heater drive time T1 (100 ms), the main detection heater drive cycle T2 ( 45 s), inspection heater driving time T3 (100 ms), inspection heater driving cycle T4 (45 s), inspection waiting time T5 (30 to 40 ms) are other values (for example, main detection heater driving time T1 and inspection heater driving time). T3 may be 90 ms, main detection heater driving cycle T2 / inspection heater driving cycle T4 may be 50 s, and inspection waiting time T5 may be 20 ms). Further, the main detection gas detection (step 14) in FIG. 3 and the first inspection gas detection (step 33) and the second inspection gas detection (step 36) in FIG. Different alarm levels may be used as shown in FIG.

  Next, the eighth embodiment will be described. In the eighth embodiment, gas detection is performed using the configuration of the gas alarm device 10 of the seventh embodiment as it is, and the normal monitoring mode is the same, but the gas detection in the inspection mode is further improved. . Specifically, the main detection heater driving time T1 in the normal monitoring mode is different from the inspection heater driving time T3 in the inspection mode. That is, as shown in FIGS. 13A and 13B, the inspection heater driving time T3 in the inspection mode is longer than the main detection heater driving time T1 in the normal monitoring mode. For example, while the main detection heater driving time T1 in the main detection mode is 100 ms, the inspection standby time T5 is the same between 30 and 40 ms, but the inspection heater driving time T3 is 200 ms. The present inventors have found that this inspection is particularly suitable for detecting methane gas.

The main detection heater driving time T1 (100 ms), the main detection heater driving cycle T2 (45 s), the inspection heater driving time T3 (200 ms), the inspection heater driving cycle T4 (45 s), and the inspection waiting time T5 (30 to 40 ms). The other values (for example, the main detection heater driving time T1 is 90 ms, the inspection heater driving time T3 is 250 ms, the main detection heater driving period T2 and the inspection heater driving period T4 are 50 s, and the inspection waiting time T5 is 20 ms. Yes). The optimum value may be selected according to the actual condition on condition that the inspection heater driving time T3> the main detection heater driving time T1 is satisfied.
Such a gas alarm device 10 may be used.

  Next, the ninth embodiment will be described. In the ninth embodiment, the first and second inspection alarm levels in the inspection mode are higher than the main detection alarm level in the normal monitoring mode with respect to the gas alarm device 10 in the seventh and eighth embodiments described above. It is designed to be lower. For example, for the first inspection alarm level, as shown in FIG. 2, the main detection alarm level for methane gas in the normal monitoring mode is 3000 ppm, whereas the inspection alarm level for methane gas in the inspection mode is 2000 ppm. Yes. Further, by lowering the second inspection alarm level, hydrogen gas and carbon monoxide gas can be reliably detected as well. If it does in this way, it will detect even if there is little fall of a sensor resistance value, and quick and reliable detection is attained. Such a gas alarm device 10 may be used.

  Next, the tenth embodiment will be described. In the tenth embodiment, in addition to the gas alarm device 10 of the seventh, eighth and ninth embodiments described above, the heater detection main driving cycle T2 of the heater drive in the normal monitoring mode and the heater drive in the inspection mode are further provided. The inspection heater driving cycle T4 is made different. That is, as shown in FIGS. 14 (a) and 14 (b), applied to the seventh embodiment, and applied to the eighth embodiment as FIGS. 15 (a) and 15 (b), as shown in the inspection mode. The inspection heater driving cycle T4 is shorter than the main detection heater driving cycle T2 in the normal monitoring mode. For example, the main detection heater driving period T2 in the normal monitoring mode is 45 s, whereas the inspection heater driving period T4 in the inspection mode is 10 s. In this inspection, particularly, the inspection gas is repeatedly detected in a short time, so that it is detected quickly and reliably. Furthermore, the present invention may be applied in addition to the ninth embodiment described above.

  14A and 14B, the main detection heater driving time T1 (100 ms), the main detection heater driving cycle T2 (45 s), the inspection heater driving time T3 (100 ms), and the inspection heater driving cycle T4 ( 10s), the inspection waiting time T5 (30 to 40 ms) is a value other than this (for example, the main detection heater driving time T1 and the inspection heater driving time T3 are set to 90 ms, the main detection heater driving cycle T2 is set to 50 s, and the inspection heater driving is performed. The period T4 may be 8 s and the inspection waiting time T5 may be 25 ms). The optimum value may be selected according to the actual condition on condition that the detection heater driving cycle T2> the inspection heater driving cycle T4 is satisfied.

Further, as shown in FIGS. 15A and 15B, the main detection heater driving time T1 (100 ms), the main detection heater driving cycle T2 (45 s), the inspection heater driving time T3 (200 ms), and the inspection heater driving cycle T4 ( 10s), the inspection waiting time T5 (30 to 40 ms) is a value other than this (for example, the main detection heater driving time T1 is 90 ms, the inspection heater driving time T3 is 250 ms, the main detection heater driving period T2 is 50 s, The inspection heater drive cycle T4 may be 8 s, and the inspection standby time T5 may be 25 ms). The optimum value may be selected according to the actual condition on condition that the main detection heater driving time T1 <the inspection heater driving time T3 and the main detection heater driving period T2> the inspection heater driving period T4.
Such a gas alarm device 10 may be used.

  Next, the eleventh embodiment will be described. In the eleventh embodiment, the delay time from the start of alarm in the inspection mode to the alarm is further different from that in the normal monitoring mode with respect to the gas alarm device 10 in the seventh, eighth, ninth, and tenth embodiments described above. The delay time from the alarm start to the alarm is shorter. It waits until a predetermined delay time elapses after the gas is detected, and if the gas is detected even after the elapse of the delay time, it is determined that the gas is detected. Since the delay time from alarm start to alarm in the normal monitoring mode is long, the alarm is detected for the first time when it is detected many times repeatedly, but false alarms are reduced because it is an error in one detection . On the other hand, in the inspection, since the delay time from the start of the alarm in the inspection mode to the alarm is shortened, an alarm is issued immediately after the detection, and the inspection ends early. In addition, it is good also as change of the repetition frequency of gas detection instead of the change of delay time. For example, in the normal inspection mode, it is determined that the detected gas has been detected ten times continuously, but in the inspection mode, it may be determined that the inspection gas has been detected three times in succession. Moreover, it is good also as an immediate alarm by making delay time zero. Such a count is also included in the change of the delay time. Such a gas alarm device 10 may be used.

The gas alarm device of the present invention has been described above. For LP gas, an LP gas stove or gas lighter is ignited and the burned gas is used. Such inspection gas for LP gas is butane, hydrogen, and carbon monoxide (CO).
Although this description is about the inspection with a mixed gas, in the case of a single gas alarm device, such a gas alarm device 10 may be used even with one inspection gas such as methane gas, CO gas, or butane.
In addition, although this description is about a semiconductor type gas sensor whose resistance value is low with respect to gas, there is a gas sensor whose resistance value increases such as a catalytic combustion type gas sensor, and “low resistance value” means “sensor sensitivity is low”. The gas alarm device 10 may be replaced with “low”.

  In the present invention, the gas alarm device 10 is repaired or exchanged so that the inspection can be easily performed, so that it is possible to avoid a situation in which even if there is an alarm level gas leak, it cannot be detected. .

10: Gas alarm device 11: Gas sensor 11a: Sensor resistor 11b: Heater resistor 12: Control circuit unit 13: Alarm unit 13a: Alarm sound output unit 13b: Alarm display unit 13c: External alarm output unit 14: Alarm stop switch 15: Battery Unit 16: Power supply unit 17: Power supply circuit unit R: Load resistor R2: Shunt resistor SW1: Transistor switch SW2: Transistor switch

Claims (7)

A gas sensor comprising: a heater having a temperature at which the inspection gas or the main detection gas is detected; and a gas detection unit that changes a sensor resistance value in response to the inspection gas or the main detection gas while being heated by the heater;
An alarm unit for outputting an alarm;
An alarm stop switch to stop the alarm output;
A control circuit to which the heater, the gas detection unit, the alarm unit, and the alarm stop switch are connected, and controls to perform detection in a normal monitoring mode for detecting the detected gas and detection in an inspection mode for detecting the inspection gas. And
With
The control circuit unit is
A predetermined operation of the alarm stop switch causes a transition from the normal monitoring mode to the inspection mode, and then a transition to the normal monitoring mode when a predetermined inspection time elapses, and pulse energization that repeats the heater at a predetermined cycle. Has the function to perform this detection and inspection by
In the normal monitoring mode to detect this detection gas,
A main detection heater driving means for driving the heater over a main detection heater driving time so that the gas detection unit reaches a main detection gas detection temperature, and the gas detection unit after the main detection heater driving time has elapsed from the start of the main detection heater driving. The detection sensor resistance value acquisition means for obtaining the detection sensor resistance value and the detection gas detection means for determining that the detection gas is detected when the detection sensor resistance value is lower than the detection alarm level, It functions repeatedly with a predetermined main detection heater drive cycle, and
During the inspection mode to detect inspection gas,
Inspection heater driving means for driving the heater over an inspection heater driving time longer than the main detection heater driving time so that the gas detection unit reaches the inspection gas detection temperature, and the passage of the inspection heater driving time from the start of the inspection heater driving The inspection sensor resistance value acquisition means for obtaining the inspection sensor resistance value of the gas sensing unit later, and the inspection gas detection means for determining that the inspection gas is detected when the inspection sensor resistance value is lower than the inspection alarm level, A gas alarm characterized by repeatedly functioning in the inspection heater driving cycle.   The gas alarm device according to claim 1, wherein an inspection alarm level in the inspection mode is lower than a main detection alarm level in the normal monitoring mode. A gas sensor comprising: a heater having a temperature at which the inspection gas or the main detection gas is detected; and a gas detection unit that changes a sensor resistance value in response to the inspection gas or the main detection gas while being heated by the heater;
An alarm unit for outputting an alarm;
An alarm stop switch to stop the alarm output;
A control circuit to which the heater, the gas detection unit, the alarm unit, and the alarm stop switch are connected, and controls to perform detection in a normal monitoring mode for detecting the detected gas and detection in an inspection mode for detecting the inspection gas. And
With
The control circuit unit is
A predetermined operation of the alarm stop switch causes a transition from the normal monitoring mode to the inspection mode, and then a transition to the normal monitoring mode when a predetermined inspection time elapses, and pulse energization that repeats the heater at a predetermined cycle. Has the function to perform this detection and inspection by
In the normal monitoring mode to detect this detection gas,
A main detection heater driving means for driving the heater over a main detection heater driving time so that the gas detection unit reaches a main detection gas detection temperature, and the gas detection unit after the main detection heater driving time has elapsed from the start of the main detection heater driving. The detection sensor resistance value acquisition means for obtaining the detection sensor resistance value and the detection gas detection means for determining that the detection gas is detected when the detection sensor resistance value is lower than the detection alarm level, It functions repeatedly with a predetermined main detection heater drive cycle, and
During the inspection mode to detect inspection gas,
Inspection heater driving means for driving the heater over an inspection heater driving time longer than the main detection heater driving time so that the gas sensing unit reaches an inspection gas detection temperature, and a predetermined inspection waiting time has elapsed since the start of the inspection heater driving A first inspection sensor resistance value acquisition means for obtaining a first inspection sensor resistance value of the gas sensing unit later, and a first inspection gas detected when the first inspection sensor resistance value is lower than the first inspection alarm level; First inspection gas detection means for determining the second inspection sensor resistance value acquisition means for obtaining the second inspection sensor resistance value of the gas sensing section after the inspection heater driving time from the start of inspection heater driving, and second inspection sensor resistance As a second inspection gas detection means for determining that the second inspection gas is detected when the value is lower than the second inspection alarm level, it is repeated at a predetermined inspection heater driving cycle. Gas detector, characterized by ability. A gas sensor comprising: a heater having a temperature at which the inspection gas or the main detection gas is detected; and a gas detection unit that changes a sensor resistance value in response to the inspection gas or the main detection gas while being heated by the heater;
An alarm unit for outputting an alarm;
An alarm stop switch to stop the alarm output;
A control circuit to which the heater, the gas detection unit, the alarm unit, and the alarm stop switch are connected, and controls to perform detection in a normal monitoring mode for detecting the detected gas and detection in an inspection mode for detecting the inspection gas. And
With
The control circuit unit is
A predetermined operation of the alarm stop switch causes a transition from the normal monitoring mode to the inspection mode, and then a transition to the normal monitoring mode when a predetermined inspection time elapses, and pulse energization that repeats the heater at a predetermined cycle. Has the function to perform this detection and inspection by
In the normal monitoring mode to detect this detection gas,
A main detection heater driving means for driving the heater over a main detection heater driving time so that the gas detection unit reaches a main detection gas detection temperature, and the gas detection unit after the main detection heater driving time has elapsed from the start of the main detection heater driving. The detection sensor resistance value acquisition means for obtaining the detection sensor resistance value and the detection gas detection means for determining that the detection gas is detected when the detection sensor resistance value is lower than the detection alarm level, It functions repeatedly with a predetermined main detection heater drive cycle, and
During the inspection mode to detect inspection gas,
Inspection heater driving means for driving the heater over an inspection heater driving time so that the gas detection unit reaches an inspection gas detection temperature, and a first inspection of the gas detection unit after a predetermined inspection waiting time has elapsed from the start of the inspection heater driving. First inspection sensor resistance value acquisition means for obtaining a sensor resistance value, and first inspection gas detection means for determining that the first inspection gas is sensed when the first inspection sensor resistance value is lower than the first inspection alarm level. And second inspection sensor resistance value acquisition means for obtaining a second inspection sensor resistance value of the gas sensing unit after the inspection heater driving time from the start of the inspection heater driving, and the second inspection sensor resistance value is lower than the second inspection alarm level. As the second inspection gas detection means for determining that the second inspection gas has been detected when it is low, it functions repeatedly with a predetermined inspection heater driving cycle,
The gas alarm device characterized in that the first inspection alarm level and the second inspection alarm level in the inspection mode are lower than the main detection alarm level in the normal monitoring mode.   The gas alarm device according to any one of claims 1 to 4, wherein the predetermined operation of the alarm stop switch is an operation of continuously pressing for a longer time than a preset time. .   The inspection heater driving cycle of the heater driving in the inspection mode is shorter than the main detection heater driving cycle of the heater driving in the normal monitoring mode. The gas alarm described.   The delay time from the alarm start to the alarm in the inspection mode is shorter than the delay time from the alarm start to the alarm in the normal monitoring mode, according to any one of claims 1 to 6. The gas alarm described.

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