Gas detector

Abstract

To provide a gas detector capable of confirming a state of occurrence of a gas leakage even in a place where the gas detector is installed.SOLUTION: A gas detector 1 is installed in a space arranged underground, and includes: a sensor unit 2 for detecting gas; and a detector main body 3 connected to the sensor unit 2 and adjacently installed to the sensor unit 2. The sensor unit 2 detects gas and calculates a gas concentration of the gas based on a detected detection signal. The detector main body 3 receives the calculated gas concentration from the sensor unit 2 and determines whether the gas is being leaked in the ground based on the calculated gas concentration. The detector main body 3 reports, in the detector main body 3, the calculated gas concentration and / or a determination result on whether the gas is being leaked, and transmits the report to an outside of the detector main body 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gas detector. [Background technology]

[0002] Conventionally, gas detectors such as those disclosed in Patent Document 1 have been used to detect gas leakage from gas pipes buried underground. The gas detector in Patent Document 1 includes a gas sensor that is installed in a gas detection hole provided underground and detects gas leaked into the ground, and a detector body that is connected to the gas sensor and installed adjacent to the gas sensor. The detector body processes information obtained by the gas sensor and wirelessly transmits the detection information to an apparatus body that is installed in a management headquarters or the like outside the detector body. The apparatus body calculates the actual gas concentration based on the received detection information. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-101705 Summary of the Invention [Problem to be solved by the invention]

[0004] In the gas detector of Patent Document 1, the gas concentration is calculated by the device main body that is installed in a location away from the location where the gas detector is installed, so it is not possible to check the gas leakage status at the location where the gas detector is installed. In particular, if the communication function of the gas detector main body is damaged or a problem occurs in the communication line, it is not possible to transmit the detection information to the device main body, and it is not even possible to calculate the actual gas concentration.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide a gas detector that makes it possible to check the occurrence of a gas leak even in the location where the gas detector is installed. [Means for solving the problem]

[0006] The gas detector of the present invention is a gas detector for detecting gas leaking into the ground, the gas detector being installed in a space provided underground and comprising a sensor unit for detecting the gas, and a detector main body connected to the sensor unit and installed adjacent to the sensor unit, the sensor unit being configured to detect the gas and calculate a gas concentration of the gas based on a detected detection signal, the detector main body being configured to receive the calculated gas concentration from the sensor unit and determine whether or not the gas has leaked into the ground based on the calculated gas concentration, and the detector main body being configured to notify the calculated gas concentration and / or the determination result of whether or not the gas has leaked on the detector main body and to transmit it to the outside of the detector main body.

[0007] It is also preferable that both the sensor unit and the detector body include a memory for storing the calculated gas concentration.

[0008] Furthermore, it is preferable that the sensor unit comprises a gas sensor that detects the gas and a housing that houses the gas sensor, and that the housing is configured to be erected on the underground floor surface that defines the vertical lower side of the space, and that when the housing is erected on the floor surface, the housing has an opening at a position facing the floor surface through which the gas can enter the housing, and a plurality of legs protruding toward the floor surface around the opening, and that gaps are provided between the plurality of legs through which the gas can pass.

[0009] It is also preferable that the sensor unit is accommodated in the housing and includes a sensor control board that controls the gas sensor, and that a detector body side cable that is connected to the detector body is connected to one end of the sensor control board, and a gas sensor side cable that is connected to the gas sensor is connected to the other end of the sensor control board, and that the sensor control board is held within the housing only by the detector body side cable and the gas sensor side cable.

[0010] In addition, it is preferable that the detector body be configured to transmit information relating to the result of the determination that the gas is leaking into the ground to a pre-registered destination when the detector body determines that the gas is leaking into the ground. Effect of the Invention

[0011] According to the present invention, it is possible to provide a gas detector that is capable of checking the occurrence of a gas leak even in the location where the gas detector is installed. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing a gas detector according to an embodiment of the present invention; [Diagram 2] 1 is a block diagram showing a gas detector according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a perspective view showing the external appearance of a sensor unit of the gas detector of FIG. [Figure 4] 2 is a perspective view showing the internal structure of a housing of a sensor unit of the gas detector of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a gas detector according to an embodiment of the present invention will be described with reference to the accompanying drawings. However, the following embodiment is merely an example, and the gas detector of the present invention is not limited to the following embodiment.

[0014] The gas detector 1 of this embodiment is used to detect gas leaking underground. The gas detector 1 is installed underground under the ground G for a predetermined period of time, for example, in a handhole H provided near a gas pipe P buried underground as shown in Fig. 1, and detects city gas leaking from the gas pipe P. However, the gas detector 1 is not limited to detecting city gas, and can also detect gases other than city gas as long as the gas leaks underground and needs to be detected.

[0015] The hand hole H in which the gas detector 1 can be installed has spaces S1 and S2 in which the gas detector 1 is installed, as shown in FIG. 1. The hand hole H is provided underground adjacent to the ground G in the vicinity of the gas pipe P in order to detect gas leaking from the gas pipe P for a predetermined period of time, for example, after construction of the gas pipe P. In this embodiment, the spaces S1 and S2 include a first space S1 in which a sensor unit 2 described later is installed, and a second space S2 in which a detector main body 3 described later is installed. The first space S1 is provided below the second space S2 adjacent to the second space S2, and the second space S2 is provided below the ground G adjacent to the ground G. A side wall W1 made of mortar or the like is provided on the side of the second space S2, and an upper wall W2 that closes the second space S2 is provided above the second space S2. The gas detector 1 is installed on underground floor surfaces F1, F2 (soil surface in the illustrated example) that define the vertical lower sides of the spaces S1, S2. However, the location where the gas detector 1 is installed may be any space provided underground below the ground surface G, and is not limited to the hand hole H.

[0016] 1, the gas detector 1 includes a sensor unit 2 that detects gas, and a detector body 3 connected to the sensor unit 2. The sensor unit 2 and the detector body 3 are connected via a communication cable (detector body side cable) 4. As the communication cable 4, a known communication cable such as an RS485 cable can be used. However, the sensor unit 2 and the detector body 3 may also be connected by a known wireless communication system.

[0017] As shown in FIG. 1, the sensor unit 2 is installed in a space S1 provided underground and detects gas leaking into the ground. The sensor unit 2 is configured to detect a gas and calculate a gas concentration of the gas based on a detection signal detected. The specific configuration of the sensor unit 2 is not particularly limited as long as the sensor unit 2 is configured to detect a gas and calculate a gas concentration of the gas based on a detection signal detected. In this embodiment, in order to realize the configuration, the sensor unit 2 includes a gas sensor 21 that detects a gas and a control unit 22 that controls the gas sensor 21, as shown in FIG. 2. The sensor unit 2 may further include a memory 23 that stores the gas concentration.

[0018] The gas sensor 21 detects gas and outputs a detection signal corresponding to the presence or absence and / or concentration of the gas. As shown in FIG. 2, the gas sensor 21 is communicatively connected to the control unit 22 and configured to send a detection signal to the control unit 22. In this embodiment, the gas sensor 21 is configured as a known catalytic combustion type gas sensor. The catalytic combustion type gas sensor is configured so that a resistance value changes when a gas comes into contact with the gas and burns. The gas sensor 21 is connected to a detection circuit (not shown) configured, for example, as a known Wheatstone bridge circuit, and is connected to the control unit 22 via the detection circuit. The detection circuit is connected to the gas sensor 21 to detect a change in the resistance value of the gas sensor 21, and is configured so that a change in potential difference occurs due to the change in the resistance value of the gas sensor 21. The detection circuit outputs a change in potential difference caused by the change in the resistance value of the gas sensor 21 as a detection signal corresponding to the presence or absence and / or concentration of the gas to be detected. In this embodiment, the detection circuit is provided on a sensor control board 24 (see FIG. 4) described later. However, the gas sensor 21 is not limited to the above configuration as long as it can output a detection signal corresponding to the presence and / or concentration of gas. The gas sensor 21 may be configured with other known gas sensors, such as a semiconductor gas sensor or an electrochemical gas sensor. The gas sensor 21 may also be connected to a detection circuit other than the Wheatstone bridge circuit.

[0019] The gas sensor 21 can be configured to perform gas detection at all times (at all times drive mode) or can be configured to perform gas detection intermittently (intermittent drive mode). By performing gas detection at all times, detailed gas detection can be realized. By performing gas detection intermittently, gas detection can be efficiently performed over a long period of time. The gas sensor 21 may further be configured to be able to switch between the at all times drive mode and the intermittent drive mode.

[0020] The control unit 22 controls the gas sensor 21 and receives a detection signal output from the gas sensor 21. In this embodiment, the control unit 22 controls the gas sensor 21 via a detection circuit and receives a detection signal output from the gas sensor 21 via the detection circuit. In this embodiment, the control unit 22 operates the gas sensor 21 at a predetermined time interval (for example, at 10-minute intervals) and receives a detection signal from the gas sensor 21. The control unit 22 calculates a gas concentration based on the received detection signal. The control unit 22 stores the calculated gas concentration in the memory 23 and / or transmits the calculated gas concentration to the detector main body 3. The control unit 22 can be configured using, for example, a known central processing unit (CPU) and is provided on a sensor control board 24 (see FIG. 4) described later in this embodiment.

[0021] The memory 23 stores the gas concentration calculated by the control unit 22. The memory 23 may store the gas concentration together with the time when the detection signal on which the calculated gas concentration is based was obtained. In this embodiment, the memory 23 is communicatively connected to the control unit 22 as shown in FIG. 2. The memory 23 may be configured with a known non-volatile memory such as a flash memory, and in this embodiment, it is provided on a sensor control board 24 (see FIG. 4) described later. Even if an event occurs in which the gas concentration cannot be transmitted to the detector main body 3, the sensor unit 2 stores the gas concentration in the memory 23, so that the stored data can be retrieved and checked later.

[0022] The sensor unit 2 will be described in more detail with reference to Figs. 3 and 4. Fig. 3 is a perspective view showing the exterior of the sensor unit 2, and Fig. 4 is a perspective view showing the internal structure of the housing 25 of the sensor unit 2. The sensor unit 2 includes the above-mentioned gas sensor 21 for detecting gas, a sensor control board 24 for controlling the gas sensor 21, and a housing 25 for accommodating the gas sensor 21 and the sensor control board 24. In the gas detector 1 of this embodiment, the sensor control board 24 for controlling the gas sensor 21 is provided in the sensor unit 2, so that a detection signal such as a change in resistance value of the gas sensor 21 can be measured in the sensor unit 2. For example, when the detection signal of the gas sensor 21 is measured in the detector body 3, there is a possibility that the detection signal may be deteriorated due to a voltage drop or the like when the detection signal of the gas sensor 21 is sent from the sensor unit 2 to the detector body 3. In the gas detector 1 of this embodiment, since the detection signal can be measured in the sensor unit 2, deterioration of the detection signal caused by sending the detection signal to the detector body 3 can be suppressed, and gas can be detected with high accuracy. The sensor unit 2 further includes a filter 26 disposed upstream of the gas sensor 21 .

[0023] The sensor control board 24 is provided with the above-mentioned detection circuit, the control unit 22, and the memory 23 (see FIG. 2). As shown in FIG. 4, the sensor control board 24 is connected at one end to the detector body side cable 4 connected to the detector body 3, and at the other end to the gas sensor side cable 27 connected to the gas sensor 21. The sensor control board 24 is communicatively connected to the detector body 3 via the detector body side cable 4, and communicatively connected to the gas sensor 21 via the gas sensor side cable 27. The sensor control board 24 is held in the housing 25 by only the detector body side cable 4 and the gas sensor side cable 27. This makes it easier to install and replace the sensor control board 24 than when it is fixed and held in the housing 25. As shown in FIG. 4, the sensor control board 24 is provided with shock-absorbing cushioning material 24a at one end and the other end. As a result, even if sensor control board 24 swings within housing 25 and hits a wall surface or gas sensor 21, the shock is absorbed by cushioning material 24a, and damage can be suppressed. As long as sensor control board 24 is housed within housing 25, it is not limited to the above-mentioned configuration and may be fixed to housing 25.

[0024] In this embodiment, the housing 25 accommodates the gas sensor 21, the sensor control board 24, and the filter 26. As shown in Fig. 1, the housing 25 is configured to be erected on an underground floor surface F1 that defines the vertical lower side of the first space S1. As also shown in Fig. 3, when the housing 25 is erected on the floor surface F1, an opening 25a through which gas can enter the housing 25 and a plurality of legs 25b protruding toward the floor surface F1 around the opening 25a are provided at a position of the housing 25 facing the floor surface F1. Gaps 25c through which gas can pass are provided between the plurality of legs 25b. The housing 25 is erected in the first space S1 with the legs 25b in contact with the floor surface F1. At this time, the opening 25a is not blocked by the floor surface F1. Therefore, not only the gas entering the first space S1 from the floor surface F1 located on the lower side of the first space S1, but also the gas entering the first space S1 from the side of the first space S1 can reach the opening 25a through the gap 25c and enter the housing 25. Therefore, by providing the gap 25c between the multiple legs 25b, the detection sensitivity of the sensor unit 2 to gas is improved. However, the housing 25 does not necessarily have to be provided with the legs 25b. In that case, for example, in addition to the opening 25a provided on the lower surface of the housing 25 (at a position facing the floor surface F1), a hole through which gas can pass may be formed on the side of the housing 25.

[0025] The housing 25 may have any shape as long as it can accommodate the gas sensor 21, the sensor control board 24, and the filter 26. In this embodiment, as shown in FIG. 3, the housing 25 has a space therein for accommodating the gas sensor 21, the sensor control board 24, and the filter 26, and is formed in a substantially cylindrical shape extending in one direction. The housing 25 has the detector body side cable 4 connected to one end side in the direction in which the housing 25 extends, and an opening 25a and a leg 25b are provided at the other end side in the direction in which the housing 25 extends. The filter 26 is provided inside the housing 25 so as to face the opening 25a, and the gas sensor 21, the gas sensor side cable 27, the sensor control board 24, and the detector body side cable 4 are accommodated in this order from the filter 26 toward the one end side of the housing 25.

[0026] The filter 26 is provided to prevent at least a portion of components other than the gas to be detected from entering the gas sensor 21. In this embodiment, the filter 26 is composed of a water-repellent filter and a silver filter. The sensor unit 2 includes the water-repellent filter to prevent interfering components such as water and dust from entering the gas sensor 21, and the sensor unit 2 includes the silver filter to prevent interfering components such as volatile components of organic solvents from entering the gas sensor 21.

[0027] The detector body 3 connected to the sensor unit 2 is configured to receive the calculated gas concentration from the sensor unit 2 and determine whether or not gas is leaking underground based on the calculated gas concentration. The detector body 3 is configured to notify the calculated gas concentration and / or the determination result of whether or not gas is leaking on the detector body 3 and to transmit the same to the outside of the detector body 3. In this way, the detector body 3 can not only transmit the calculated gas concentration and / or the determination result of whether or not gas is leaking to the outside of the detector body 3, but also notify the same on the detector body 3, so that even if a malfunction occurs in the function of the detector body 3 to transmit to the outside, the occurrence of a gas leak can be confirmed at the location where the gas detector 1 is installed.

[0028] Furthermore, as described in detail below, the detector main body 3 may be configured to transmit information about the result of the gas leak determination to a pre-registered destination when it is determined that gas is leaking underground. The information about the result of the gas leak determination includes an alert to warn the registered destination that a gas leak has occurred, the gas concentration at that time, the time, etc. By receiving the information about the result of the gas leak determination, the registered destination can quickly take measures against the gas leak.

[0029] 1, the detector body 3 is installed adjacent to the sensor unit 2. In this embodiment, the detector body 3 is placed on an underground floor surface F2 that defines the lower side in the vertical direction of the second space S2 provided adjacent to the underground first space S1 in which the sensor unit 2 is installed, and is installed in the second space S2. However, as long as the detector body 3 is connected to the sensor unit 2 and installed in the vicinity of the sensor unit 2, it does not necessarily have to be installed in the underground space S2, and may be installed in a space other than underground, such as on the ground G.

[0030] As described above, the detector body 3 is not particularly limited in its specific configuration as long as it is configured to determine the presence or absence of a gas leak from the gas concentration, and to notify the gas concentration and / or the determination result on the detector body 3 and to transmit the same to the outside of the detector body 3. In this embodiment, in order to realize the above configuration, the detector body 3 includes a control unit 31, a communication unit 32, a notification unit 33, a memory 34, and a power source 35, as shown in Fig. 2.

[0031] The control unit 31 receives the gas concentration calculated by the sensor unit 2 from the sensor unit 2. The control unit 31 determines whether or not gas is leaking underground based on the received gas concentration. For example, when the gas concentration is lower than a predetermined threshold, the control unit 31 determines that gas is not leaking underground, and when the gas concentration is higher than the predetermined threshold, the control unit 31 determines that gas is leaking underground. The control unit 31 notifies the gas concentration and / or the determination result by the notification unit 33, and transmits the gas concentration and / or the determination result to the outside of the detector main body 3 by the communication unit 32. The control unit 31 can also store the gas concentration and / or the determination result in the memory 34.

[0032] When the control unit 31 determines that gas has not leaked underground for a predetermined period (e.g., 24 hours), after the predetermined period (e.g., 24 hours) has elapsed, it transmits all of the gas concentrations measured during the predetermined period and stored in the memory 34 to an external location of the detector main body 3 (e.g., a registration destination (periodic registration destination) such as a management headquarters that has been registered in advance). This enables the registration destination to check the progress of the gas concentration over the predetermined period and to confirm that gas has not leaked underground. At this time, the control unit 31 may be configured to notify the gas concentration and / or the determination result by the notification unit 33. This allows the gas concentration and / or the determination result to be confirmed even at the location where the gas detector 1 is installed.

[0033] Furthermore, when the control unit 31 determines that gas is leaking underground, it transmits information on the result of the determination that gas is leaking not only to a previously registered destination (regular registration destination) such as a management headquarters outside the detector main body 3, but also to a previously registered destination (emergency registration destination) such as a mobile terminal of an administrator. This allows the registered destination to know the information that gas is leaking in real time, and to take measures against the gas leak promptly. Furthermore, when the control unit 31 determines that gas is leaking underground, it is configured to notify the gas concentration and / or the determination result by the notification unit 33. This allows the occurrence of a gas leak to be confirmed at the location where the gas detector 1 is installed, even if a malfunction occurs in the function of transmitting to the outside of the detector main body 3.

[0034] The communication unit 32 wirelessly transmits information including the gas concentration and / or the determination result to the outside of the detector body 3. In addition to the gas concentration and the determination result, the communication unit 32 may transmit the time when the gas was detected, the temperature, and the like, and may transmit information indicating the remaining power supply. As shown in FIG. 2, the communication unit 32 is communicatively connected to the control unit 31, and is configured to transmit information to a preregistered destination, for example, upon receiving an instruction from the control unit 31. The communication unit 32 is not particularly limited in its communication method as long as it can wirelessly transmit information to the outside of the detector body 3, and is configured to transmit information by, for example, the LTE communication method. In addition, the communication unit 32 is not particularly limited in its transmission form, and can transmit information by, for example, email.

[0035] The notification unit 33 notifies the user of the gas detector 1 of the gas concentration and / or the determination result on the detector body 3 so that the user can recognize the gas concentration and / or the determination result. As shown in FIG. 2, the notification unit 33 is communicably connected to the control unit 31, and notifies the user of the gas detector 1 of the gas concentration and / or the determination result upon receiving an instruction from the control unit 31. The notification method of the notification unit 33 is not particularly limited as long as the user of the gas detector 1 can recognize the gas concentration and / or the determination result. In this embodiment, the notification unit 33 can be embodied, for example, as shown in FIG. 1, by a display 33a that visually notifies the gas concentration, a speaker 33b that audibly notifies the determination result, a lamp 33c that visually notifies the determination result, and the like. For example, when it is determined that gas is not leaking underground, the speaker 33b notifies the user by not emitting a sound, and the lamp 33c notifies the user by turning off. Moreover, if it is determined that gas is leaking underground, the speaker 33b notifies the user by emitting an alarm, and the lamp 33c notifies the user by turning on.

[0036] The memory 34 stores the gas concentration calculated by the sensor unit 2. The memory 34 may store the gas concentration together with the time when the detection signal on which the calculated gas concentration is based was obtained. The memory 34 may also store the result of the determination by the control unit 31 as to whether or not gas is leaking underground. In this embodiment, the memory 34 is communicatively connected to the control unit 31 as shown in FIG. 2. The memory 34 can be configured, for example, by a known non-volatile memory such as a flash memory. By providing the detector body 3 with the memory 34 for storing the gas concentration (and optionally the determination result), even if a situation occurs in which the gas concentration (and optionally the determination result) cannot be transmitted to the outside of the detector body 3, the stored data can be retrieved and checked later. In particular, in this embodiment, the sensor unit 2 also has the memory 23 for storing the gas concentration, and the gas concentration can be stored in the sensor unit 2 even if the communication cable 4 has a communication failure, so that the leakage status of gas underground can be monitored more reliably.

[0037] The memory 34 can also store information on destinations (registration destinations) to which information on the calculated gas concentration and / or the determination result as to whether or not gas is leaking is sent. Examples of the registration destinations include a regular registration destination (such as a personal computer at the management headquarters) to which information is sent regardless of the determination result as to whether or not gas is leaking underground, and an emergency registration destination (such as a mobile terminal of the administrator) to which information is sent when it is determined that gas is leaking underground. Examples of the registration destination information include the name or title of the registration destination, the registration destination's email address, etc.

[0038] In the gas detector 1 of this embodiment, as described above, memories 23, 34 are provided in both the sensor unit 2 and the detector body 3, respectively, in order to store the calculated gas concentration. However, as long as the gas detector 1 can store the gas concentration, the memory may be provided in only one of the sensor unit 2 and the detector body 3, or the memory may be provided externally, separate from the sensor unit 2 and the detector body 3. When a memory is provided in only one of the sensor unit 2 and the detector body 3, it is preferable that the memory be provided in the detector body 3 from the viewpoint of ease of confirmation by the user.

[0039] The power supply 35 is a power supply source for the components of the detector body 3. In this embodiment, as shown in Fig. 2, the power supply 35 supplies power to the control unit 31, and also supplies power to the communication unit 32, the notification unit 33, and the memory 34. In this embodiment, the power supply 35 also supplies power to the sensor unit 2. However, the sensor unit 2 may have its own power source without receiving power from the power supply 35. In this embodiment, the power supply 35 is configured by an internal power source such as a battery, but may be configured by an external power source. [Explanation of symbols]

[0040] 1 Gas detector 2 Sensor unit 21 Gas Sensor 22 Control section 23 Memory 24 Sensor control board 24a Cushioning material 25 Case 25a opening 25b Legs 25c gap 26 Filters 27 Gas sensor cable 3. Detector body 31 Control Unit 32 Communications Department 33 Notification Department 33a Display 33b Speaker 33c Lamp 34 Memory 35 Power supply 4 Communication cable (cable for detector body) F1 1st floor F2 Second Floor G ground H Hand Hole P Gas Pipe S1 First Space S2 The Second Space W1 side wall W2 Top wall

Claims

[Claim 1] A gas detector for detecting gas leaking underground, The gas detector comprises: A sensor unit that is installed in a space provided underground and detects the gas; a detector body connected to the sensor unit and installed adjacent to the sensor unit; Equipped with The sensor unit is configured to detect the gas and calculate a gas concentration of the gas based on a detected detection signal; The detector body is configured to receive the calculated gas concentration from the sensor unit and determine whether or not the gas is leaking into the ground based on the calculated gas concentration; The detector body is configured to notify the calculated gas concentration and / or the determination result of whether or not the gas is leaking on the detector body and to transmit the same to an outside of the detector body. Gas detector.

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