Gas detector

Abstract

The invention provides a gas detector capable of coping with various gas detection methods. The gas detector includes a main body, a first gas detection module disposed in a state of being freely separated from the main body, and a second gas detection module disposed in a state of being freely separated from the main body. The first gas detection module includes a first chamber, a first gas sensor disposed in a state of being freely separated from the first chamber, and a first sensor base disposed in a state of being freely separated from the first gas sensor. On the other hand, the second gas detection module has a second chamber and a second sensor unit disposed in a state of being freely separated from the second chamber. A connection layout of the first gas detection module with respect to the main body is the same as a connection layout of the second gas detection module with respect to the main body.

Description

Technical Field

[0001] The invention relates to a gas detector for detecting gas. Background Art

[0002] In order to detect multiple gases, there are gas detectors that can replace the gas sensor (gas detection module) used to detect the gas (see Patent Document 1). In addition, there are also gas detectors that can detect multiple gases simultaneously by installing multiple gas sensors in one gas detector (see Patent Document 2).

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 2010-218100 Patent Document 2: Japanese Patent Application Laid-Open No. 2023-076338 Summary of the invention

[0004] Technical issues However, conventional gas detectors have a problem of being unable to cope with various gas detection methods because they are limited to gas detection modules having an integral casing with the same external shape and can be replaced with each other.

[0005] In view of this actual situation, the present invention intends to provide a gas detector that can cope with various gas detection methods.

[0006] Technical Solution The present invention associated with the above-mentioned purpose is a gas detector, characterized in that it detects gas and comprises: a main body, which has a main body-side inflow path for the gas to flow in, and a main body-side outflow path for the gas to flow out; a first gas detection module, which is configured in a state of being detachable from the main body and detects the gas; and a second gas detection module, which is configured in a state of being detachable from the main body and detects the gas, the first gas detection module comprising: a first chamber, which is configured in a state of being detachable from the main body and has a first chamber-side inflow path connected to the main body-side inflow path in a detachable manner a first chamber-side outflow passage connected to the main body-side outflow passage in a detachable manner, and a first internal space between the first chamber-side inflow passage and the first chamber-side outflow passage; a first gas sensor, which is configured in a detachable state relative to the first chamber, and whose gas detection unit contacts the gas passing through the first internal space; and a first sensor base, which is configured in a detachable state relative to the first gas sensor and has a first sensor receiving connector connected to a first sensor-side connector of the first gas sensor in a detachable manner, and a main body having a first sensor receiving connector connected to the main body in a detachable manner. The gas sensor and the main body are electrically connected to each other by a first main body receiving connector connected to the side connector, thereby making the gas sensor and the main body in an electrically connected state, the second gas detection module comprising: a second chamber, which is configured in a state detachable from the main body, and has a second chamber side inflow path connected to the main body side inflow path in a detachable manner, a second chamber side outflow path connected to the main body side outflow path in a detachable manner, and a second internal space between the second chamber side inflow path and the second chamber side outflow path; and a second sensor unit, which is configured in a state detachable from the second chamber, the second sensor of the second gas detection module The unit also comprises: a second shell; a second gas sensor, which is arranged inside the second shell and in contact with the gas passing through the second internal space; and a second main body receiving connector, which is arranged in the second shell and connected to the main body side connector of the main body in a detachable manner, and the connection layout of the first chamber side inflow path, the first chamber side outflow path and the first main body receiving connector relative to the main body in the first gas detection module is the same as the connection layout of the second chamber side inflow path, the second chamber side outflow path and the second main body receiving connector relative to the main body in the second gas detection module.

[0007] In association with the above-mentioned gas detector, it may also be characterized in that the shape of the connection interface between the first chamber in the first gas detection module and the first gas sensor is different from the shape of the connection interface between the second chamber in the second gas detection module and the second sensor unit.

[0008] In association with the above-mentioned gas detector, its feature may also be that the first chamber has a first chamber side snap-in portion, the first sensor base has a first base side snap-in portion snap-in with the first chamber side snap-in portion, and the first chamber is fixed relative to the first sensor base by snapping the first chamber side snap-in portion with the first base side snap-in portion, the second chamber has a second chamber side snap-in portion, the main body has a second main body side snap-in portion snap-in with the second chamber side snap-in portion, and the second chamber is fixed relative to the main body by snapping the second chamber side snap-in portion with the second main body side snap-in portion.

[0009] Technical Effects According to the present invention, the gas detector can flexibly cope with various gas detection methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 (A) is a perspective view of the main body of the gas detector according to the first embodiment as viewed from the front obliquely above. Figure 1 (B) is a perspective view of the main body of the gas detector according to the first embodiment as seen from the rear side obliquely below.

[0011] Figure 2 (A) is a top view of the subject. Figure 2 (B) is the main view of the subject. Figure 2 (C) is the right view of the subject. Figure 2 (D) is the left view of the subject, Figure 2 (E) is a bottom view of the subject. Figure 2 (F) is a rear view of the subject.

[0012] Figure 3 It is a perspective view of a state in which the front cover of the main body is opened.

[0013] Figure 4 This is a front view of the main body with the front cover opened.

[0014] Figure 5 It is a left side view of the main body in a state where the front mask and the left side mask are omitted.

[0015] Figure 6 This is a perspective view of a state where the pump of the main body is disassembled.

[0016] Figure 7 This is a perspective view of a state where the flow sensor of the main body is disassembled.

[0017] Figure 8 This is a front view of the main body with the pump and flow sensor removed.

[0018] Fig. 9 (A) is a perspective view of the gas detection module of the gas detector according to the first embodiment, as viewed from the back. Fig. 9 (B) is a left side view of the gas detection module of the gas detector of the first embodiment. Fig. 9 (C) is a rear view of the gas detection module of the gas detector according to the first embodiment.

[0019] Fig.10 (A) is a three-dimensional view of the gas detection module after the chamber is opened, viewed from the lower back side. Fig.10 (B) is a bottom view of the gas detection module after the chamber is opened. Fig.10 (C) is a perspective view of the gas detection module in a disassembled gas sensor state after the cavity is opened.

[0020] Fig.11 (A) is a left side view of the gas detector in a state where the main body and the gas detection module are separated. Fig.11 (B) is a left side view of the gas detector in which the gas detection module is installed in the main body.

[0021] Fig. 12A : is a block diagram showing the internal circuit structure of the gas detector.

[0022] Fig. 12B This is a block diagram showing the functional structure of the main body side computer, base side computer, and sensor side computer of the gas detector.

[0023] Fig.13A This is a block diagram showing a modified example of the internal circuit structure of the gas detector.

[0024] Fig. 13B This is a block diagram showing a modified example of the functional structure of the main body side computer, base side computer, and sensor side computer of the gas detector.

[0025] Fig.14 This is a diagram showing a determination table for determining the type of a gas detection module performed by a main body-side computer of the gas detector.

[0026] Fig.15 is a flow chart showing the steps of the gas detection procedure of the gas detector.

[0027] Fig.16(A) is a perspective view of a gas detection module of a gas detector according to a second embodiment, as viewed from the back. Fig.16 (B) is a left side view of the gas detection module of the gas detector according to the second embodiment. Fig.16 (C) is a rear view of the gas detection module of the gas detector according to the second embodiment.

[0028] Fig.17 (A) is a three-dimensional view of the gas detection module after the chamber is opened, viewed from the lower back side. Fig.17 (B) is a perspective view of the gas sensor of the gas detection module after the chamber is opened, in which the gas sensor is disassembled.

[0029] Fig.18 (A) is a left side view of the gas detector in a state where the main body and the gas detection module are separated. Fig.18 (B) is a left side view of the gas detector in which the gas detection module is installed in the main body.

[0030] Fig.19 : is a block diagram showing the internal circuit structure of the gas detector.

[0031] Fig. 20 This is a block diagram showing the functional structure of the main body side computer, base side computer, first sensor side computer, and second sensor side computer of the gas detector.

[0032] Fig.21 (A) is a perspective view of a chamber in a gas detection module of a gas detector according to a third embodiment, as viewed obliquely from the rear side above. Fig.21 (B) is a front view of a chamber in the gas detection module of the gas detector according to the third embodiment. Fig.21 (C) is a right side view of the chamber in the gas detection module of the gas detector according to the third embodiment. Fig.21 (D) is a left side view of the chamber in the gas detection module of the gas detector according to the third embodiment. Fig.21 (E) is a rear view of the chamber in the gas detection module of the gas detector according to the third embodiment.

[0033] Fig. 22 (A) is a perspective view of the sensor unit in the gas detection module viewed from the front and obliquely below. Fig. 22 (B) is a perspective view of the sensor unit in the gas detection module viewed from the back and above. Fig. 22 (C) is a rear view of the sensor unit in the gas detection module. Fig. 22 (D) is a left side view of the sensor unit in the gas detection module.

[0034] Fig.23 It is a rear view showing a state where the sensor unit in the gas detection module is connected to the chamber.

[0035] Fig.24A This is a left side view of the gas detector after the main body, sensor unit and chamber are separated. Fig. 24B This is a left side view of the gas detector after the chamber is installed on the main body. Fig.24C This is a left side view of the gas detector in a state where the sensor unit is mounted on the main body.

[0036] Fig.25 : is a block diagram showing the internal circuit structure of the gas detector.

[0037] Fig.26 This is a block diagram showing the functional structure of the main body side computer and the unit side computer of the gas detector.

[0038] Fig. 27 This is a diagram showing a determination table for determining the type of a gas sensor by a base-side computer in the gas detector according to the second embodiment.

[0039] Explanation of symbols 1: Gas detector 10: Main body 14IN: suction port 14OUT: Exhaust port 15: Rod 18: Pump 20: Flow sensor 22: Main body side inflow path 24: Main body side outflow path 26: Main body side circuit board 26A: Main body side connector 27: Auxiliary substrate on the main body side 27A: Flexible wiring 34: Main body side computer 49: Main body side snap-in part 50: Gas detection module 52: Chamber 54: Internal Space 55: Chamber side engagement portion 58: Sensor insertion port 60: Gas sensor 61: Sensor housing 62: Gas detection department 62H: Heater unit 63: Sensor side circuit board 64: Sensor side computer 65: Sensor side connector 68: Sealing surface 70: Sensor base 71: Base shell 73: Base side circuit board 74: Base side computer 75: Connector 77: Connector 79: Base side snap-in portion 102: First determination path 104: Second determination path 106: First base power path 108: Second base power path 108X: Power path for heater 110: Electric path for heater 112: First communication path 114: Reset path 116: Third determination path 118: Second communication path 130: Analog output path 202: First judgment power supply unit 204: Second judgment power supply unit 206: First base power supply unit 208: Second base power supply unit 210: Power supply unit for heater 220: Third judgment response unit 702: First judgment response unit 704: Second judgment response unit 706: Third judgment power supply unit 2001: Gas Detector 2050: Gas Detection Module 2052: Chamber 2060A: The first gas sensor 2060B: Second gas sensor 2063A: First sensor side circuit board 2063B: Second sensor side circuit board 2064A: First sensor side computer 2064B: Second sensor side computer 2065A: First sensor side connector 2065B: Second sensor side connector 2070: Sensor base 2071: Base shell 2071A: First sensor insertion opening 2071B: Second sensor insertion opening 2073: Base side circuit board 2074: Base-side computer 2075A: Connectors 2075B: Connectors 2077: Connector 2702: First judgment response unit 2704: Second judgment response unit 2706: Third judgment power supply unit 2707A: First sensor side first determination response unit 2707B: Second sensor side first determination response unit 2708A: First sensor side second determination response unit 2708B: Second sensor side second determination response unit 3001: Gas detector 3050: Gas detection module 3052: Chamber 3054: Interior Space 3055: Chamber side snap-in 3058: Unit insertion port 3060: Gas Sensor 3073: Unit side circuit board 3074: Unit-side computer 3077: Connector 3080: Sensor unit 3081: Unit housing 3090: Heater internal control unit 3130: Analog output path 3402: Judgment input processing unit 3404: Sensor judgment processing unit 3406: Input processing unit for auxiliary judgment 3408: Auxiliary sensor judgment processing unit 3410: Base power supply processing unit 3412: Path function switching processing unit 3414: Control protocol switching processing unit 3416: Sensor setting information reading unit 3418: Output demultiplexing processing unit 3420: Input multiplexing processing unit 3422: Additional Function Processing Department 3702: First judgment response unit 3704: Second judgment response unit 3706: Third judgment power supply unit 6402: Standardization Processing Department 6404: Category output processing unit 6406: Request specification output processing unit 7402: Input demultiplexing processing unit 7404: Output multiplexing processing unit 7406: Category output processing unit 7408: Request specification output processing unit 7410: Standardization Processing Department DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0041] <First Embodiment> like Fig.11 As shown, the gas detector 1 of the first embodiment includes a main body 10 and a gas detection module 50. The main body 10 and the gas detection module 50 are connected to each other in a detachable manner.

[0042] (Main body shell) like Figure 1 and Figure 2 As shown in FIG. 1 , the main body 10 includes a front mask 13A, an upper mask 13B, a rear mask 13C, a bottom mask 13D, a left mask 13E, and a right mask 13F as a shell. Figure 1 The direction from the front side toward the back side is called the “depth direction”, the direction from the top side toward the bottom side is called the “upper and lower direction”, and the direction from the right side toward the left side is called the “width direction”.

[0043] Various operation buttons 28A, a display device 28B, and an external communication connector 28C are provided in front of the front cover 13A. An inlet 14IN for sucking the atmosphere gas into the main body and an exhaust port 14OUT for exhausting the gas sucked in from the inlet 14IN are provided in the bottom cover 13D. In addition, a lever 15 operated when the gas detector 1 itself is mounted or dismounted relative to a stand (not shown) protrudes downward from the bottom cover 13D.

[0044] like Figure 3 and Figure 4As shown, a hinge 13G whose rotation axis extends in the width direction is provided at the boundary between the lower edge of the front mask 13A and the front edge of the bottom mask 13D. By means of the hinge 13G, the entire front mask 13A swings toward the near front side in the depth direction and toward the lower side in the up-down direction. As a result, the front of the internal space of the shell of the main body 10 is completely opened. An elastic body 13X is provided on the inner surface of the front mask 13A to press the gas detection module 50 toward the inner side when closed.

[0045] (Internal structure of the subject) As shown in the figure, the left side mask 13E and the front mask 13A are omitted. Figure 5 As shown, a pump 18, a flow sensor 20, a main body side inflow path 22, a main body side outflow path 24, a main body side circuit board 26 (stored in a housing), a main body side inflow port 22IN, and a main body side outflow port 24OUT are provided inside the main body 10. It should be noted that the "inflow" of the main body side inflow path 22 mentioned here means the flow from the suction port 14IN to the gas detection part of the gas detection module 50, and the "outflow" of the main body side outflow path 24 means the flow from the gas detection part of the gas detection module 50 to the exhaust port 14OUT. The main body side inflow path 22 is a gas path that directly connects the suction port 14IN and the main body side inflow port 22IN. The main body side outflow path 24 has: a first outflow path 24A that connects the main body side outflow port 24OUT and the flow sensor 20; a second outflow path 24B that connects the flow sensor 20 and the pump 18; and a third outflow path 24C that connects the pump 18 and the exhaust port 14OUT.

[0046] The pump 18 presses the gas in the outflow path 24 on the main body side in the outflow direction. The pump 18 has an electromagnetic coil 18A fixed to the housing side and a diaphragm pump body 18B driven by the electromagnetic coil 18A. The diaphragm pump body 18B has the following structure: the permanent magnet fixed to the rod vibrates due to the AC drive of the electromagnetic coil 18A, and the diaphragm fixed to the end of the rod changes the volume in the housing, thereby sending out gas. Figure 6 As shown in FIG. 1 , the diaphragm pump body 18B can be easily removed by pulling it out toward the front side. Thus, when the diaphragm pump body 18B fails, it can be quickly replaced by opening the front cover 13A.

[0047] The flow sensor 20 measures the flow rate of the gas flowing in the main body side outflow path 24. The flow sensor 20 is electrically connected via a wiring 20A with a connector extending from the main body side circuit board 26. Figure 7As shown, the flow sensor 20 is fixed to the housing by a fixing screw 20B extending in the depth direction. Therefore, by removing the wiring 20A and the fixing screw 20B, the flow sensor 20 can be easily taken out by pulling it out toward the front side in the depth direction. Thus, in the event of a failure of the flow sensor 20, it can be quickly replaced by opening the front cover 13A.

[0048] Figure 8 The main body 10 is shown in a state where both the diaphragm pump body 18B and the flow sensor 20 are removed. An outlet 24Bout of the second outflow path 24B and an inlet 24Cin of the third outflow path 24C are opened near the electromagnetic coil 18A in the main body 10. If the diaphragm pump body 18B is installed in a press-fit manner, the outlet 24Bout and the inlet 24Cin are connected to the diaphragm pump body 18B.

[0049] The outlet 24Aout of the first outflow path 24A and the inlet 24Bin of the second outflow path 24B are opened in the back of the housing at the position where the flow sensor 20 is removed. If the flow sensor 20 is installed in a press-fit manner, the outlet 24Aout and the inlet 24Bin are connected to the flow sensor 20.

[0050] Inside the main body 10, from bottom to top, the suction port 14IN and the exhaust port 14OUT, the main body side inlet 22IN and the main body side outlet 24OUT, the flow sensor 20 (outlet 24Aout and inlet 24Bin), and the pump 18 (outlet 24Bout and inlet 24Cin) are arranged in order to overlap each other in the vertical direction. As a result, the main body 10 can be constructed extremely compactly. At the same time, the pump 18 and the flow sensor 20 can be maintained from the front side without removing the main body 10 from the stand.

[0051] like Figure 8 As shown, the main body side circuit substrate 26 is arranged along the inner plane of the right side mask 13F and in parallel with the right side mask 13F. The main body side circuit substrate 26 controls the entire gas detector 1. The main body side circuit substrate 26 includes a main power supply circuit (not shown), a main body side computer (CPU) 34, a main body side memory (not shown), a main body side connector 26A, etc. The main body side connector 26A becomes a part of the interface for connecting to the gas detection module 50.

[0052] It should be noted that a main body side auxiliary substrate 27 is provided inside the front cover 13A, and is electrically connected to the main body side circuit substrate 26 by a flexible wiring 27A passing through the vicinity of the hinge 13G. As a result, the main body side auxiliary substrate 27 becomes a part of the main body side circuit substrate 26. The main body side auxiliary substrate 27 is electrically connected to various operation buttons 28A, a display device 28B, and an external communication connector 28C provided on the front cover 13A. Figure 1 As shown, the external communication connector 28C can be exposed to the outside when the front cover 13A is closed. Thus, when the front cover 13A is closed, the communication line of an external computer such as a PC can be connected to the external communication connector 28C, so that various operation buttons 28A can be operated or the display of the display device 28B can be confirmed while communicating with the external computer.

[0053] (For the main body side interface of the gas detection module) like Figure 4 As shown, the configuration of the main body side interface for connecting the main body 10 with the gas detection module 50 is divided by the main body side connector 26A, the main body side inlet 22IN, and the main body side outlet 24OUT. The main body side connector 26A provides an electrical connection function, and the main body side inlet 22IN and the main body side outlet 24OUT provide a gas connection function.

[0054] <Gas detection module> exist Fig. 9 and Fig.10 2 shows the overall structure of the gas detection module 50 . The gas detection module 50 includes a chamber 52 , a gas sensor 60 , and a sensor base 70 .

[0055] (Chamber) The chamber 52 has a chamber side inflow passage 52IN of a male structure (protruding structure) detachably connected to the main body side inflow inlet 22IN of the female structure, a chamber side outflow passage 52OUT of a male structure (protruding structure) detachably connected to the main body side outflow outlet 24OUT of the female structure, and an internal space 54 between the chamber side inflow passage 52IN and the chamber side outflow passage 52OUT. Fig.10 (A) and Fig.10As shown in (B), the internal space 54 is a cylindrical space having a bottom surface, and its annular protruding end is a sensor insertion port 58. The bottom surface of the internal space 54 is connected to the chamber side inflow path 52IN and the chamber side outflow path 52OUT. A rubber-like sealing ring is provided at the sensor insertion port 58. By bringing the sensor insertion port 58 (sealing ring) into contact with the sealing surface 68 of the gas sensor 60, which is an annular conical surface, the internal space 54 becomes a closed space. The chamber 52 has a pair of chamber side engaging portions 55 that are elastic claw structures. By engaging the chamber side engaging portion 55 with the base side engaging portion 79 that is a pair of receiving groove structures on the sensor base 70 side, the chamber 52 and the sensor base 70 are combined with each other. It should be noted that since the chamber-side engaging portion 55 has an elastic structure, if the user forcibly pulls the chamber 52 and the sensor base 70 apart, the engaging state between the chamber-side engaging portion 55 and the base-side engaging portion 79 is released and they can be separated from each other.

[0056] (Gas Sensor) like Fig. 9 As shown in (B), the gas sensor 60 includes a sensor housing 61, a gas detection unit 62, a sensor side circuit board 63, a sensor side computer 64 and a sensor side memory (not shown) mounted on the sensor side circuit board 63, and a sensor side connector 65 mounted on the sensor side circuit board 63. The sensor side circuit board 63 provides a path for transmitting power and a path for sending and receiving signals.

[0057] The sensor housing 61 is cylindrical in shape, and the end surface at the protruding end thereof serves as a detection surface of the gas detection unit 62 that contacts the gas in the internal space 54 of the chamber 52. A sealing surface 68 that is an annular tapered surface is formed around the sensor housing 61. The sensor insertion port 58 (sealing ring) of the chamber 52 contacts the sealing surface 68, whereby the internal space 54 on the gas detection unit 62 side becomes a closed space.

[0058] The gas detection unit 62 is a part that detects gas using electricity, and various detection methods can be used. For example, a new ceramic method that detects by using the heat generated when the combustible gas burns on an ultrafine particle oxidation catalyst (new ceramic), a semiconductor method that detects the change in resistance value generated when a metal oxide semiconductor contacts the detection target gas as the gas concentration, a hot wire semiconductor method that detects the change in resistance value generated when a metal oxide semiconductor sintered around a heated noble metal wire coil contacts the detection target gas as the gas concentration, a thermal conduction method that detects the change in thermal conductivity caused by the detection target gas as the gas concentration, a constant potential electrolysis method that electrolyzes the detection target gas on an electrode maintained at a constant potential and detects the current generated at this time as the gas concentration, and an infrared method that irradiates infrared rays to a measurement cell (space) and detects the change in the infrared rays caused by the absorption of the detection target gas. For example, in the case where the gas detection unit 62 is a hot wire semiconductor method, a heater part of the noble metal wire coil is built into the gas detection unit 62. That is, the gas sensor 60 has a common arrangement of the sealing surface 68 of the housing and the sensor-side connector 65 , and a plurality of types of gas sensors having different detection methods are prepared as a series.

[0059] The sensor side circuit board 63 is a circuit board that supplies power to the gas detection unit 62 and outputs the response result (analog response or digital response) of the gas detection unit 62. The sensor side computer 64 converts the analog response (measurement result) of the gas detection unit 62 into a digital signal and outputs it. The sensor side computer 64 further standardizes the digital signal and outputs it. In addition, the sensor side computer 64 outputs the category information and various setting information stored in the sensor side memory itself. The sensor side computer 64 receives the command signal sent from the main body side computer 34 or the base side computer 74, and generates / outputs the response signal based on the command.

[0060] The sensor side connector 65 is connected to the sensor receiving connector of the sensor base 70 described later in a detachable manner. The gas sensor 60 is fixed to the sensor base 70 through the sensor side connector 65. The gas sensor 60 receives power supply from the outside (sensor base 70) through the sensor side connector 65, or is controlled by the outside, or receives instructions (signals) from the outside. In addition, the gas sensor 60 outputs analog signals / digital signals to the outside (sensor base 70) through the sensor side connector 65. It should be noted that the sensor side connector 65 has protruding pins corresponding to the number of circuit paths. Electrical connection is performed by inserting the pins into the pin holes of the sensor receiving connector.

[0061] (Sensor base) like Fig. 9 (B) and Fig. 9 As shown in (C), the sensor base 70 includes a base housing 71, a base-side circuit substrate 73, a base-side computer 74 and a base-side memory (not shown) mounted on the base-side circuit substrate 73, a sensor receiving connector 75 mounted on the base-side circuit substrate 73, and a main body receiving connector 77 mounted on the base-side circuit substrate 73. The base-side circuit substrate 73 provides a path for transmitting power and a path for sending and receiving signals.

[0062] The base housing 71 is a rectangular parallelepiped housing, and contains a base-side circuit board 73. The gas sensor 60 and the chamber 52 are arranged on the back side of the base housing 71 (the back side corresponds to the back side when the sensor base 70 is set in the body 10). Fig.10 As shown, a circular sensor insertion opening 71A is formed in the base housing 71 at a position corresponding to the sensor receiving connector 75 of the base side circuit substrate 73. Due to the sensor insertion opening 71A, the entire sensor receiving connector 75 and a part of the base side circuit substrate 73 are exposed to the outside. By inserting the gas sensor 60 through the sensor insertion opening 71A, the sensor receiving connector 75 is connected to the sensor side connector 65. A square main body connection opening 71Z is formed in the base housing 71 at a position corresponding to the main body receiving connector 77 of the base side circuit substrate 73, and the main body receiving connector 77 is exposed. The main body receiving connector 77 is electrically connected to the main body side connector 26A.

[0063] A base side engaging portion 79 having a pair of receiving groove structures is formed on the base housing 71. The chamber side engaging portion 55 of the chamber 52 is engaged with the base side engaging portion 79. If the chamber 52 and the sensor base 70 are forcibly pulled apart by the user, the engaging state of the chamber side engaging portion 55 and the base side engaging portion 79 is released and can be separated from each other.

[0064] A hinge 71G is formed between the base housing 71 and the chamber 52. The chamber 52 and the sensor base 70 are swung relative to each other by the swing axis of the hinge 71G. Therefore, if the engagement state between the chamber side engaging portion 55 and the base side engaging portion 79 is released, the base housing 71 and the chamber 52 can swing relative to each other via the hinge 71G, but the connection state between each other is maintained. Thus, during the operation of detaching the gas sensor 60 from the base housing 71, the chamber 52 is prevented from falling and being damaged or lost.

[0065] The base-side computer 74 transmits the standardized digital signal received from the gas sensor 60 to the main body-side computer 34. The details will be described in the second embodiment, but in the case of a gas detection module to which a plurality of gas sensors 60 (gas detection units 62) are connected, the base-side computer 74 multiplexes the digital signal and converts it into a serial signal, and transmits it to the main body-side computer 34. It should be noted that, assuming that the gas sensor 60 is a type that does not have a sensor-side computer 64 built in, the base-side computer 74 can digitize or standardize the analog signal of the gas detection unit 62 instead of the sensor-side computer 64. The base-side computer 74 can output the category information and various setting information stored in the base-side memory itself to the main body-side computer 34. The base-side computer 74 can receive a command signal sent from the main body-side computer 34 or the sensor-side computer 64, and output a response signal based on the command.

[0066] (Sensor side interface for the main body) like Fig. 9 As shown in (C), the sensor side interface for connecting the gas detection module 50 to the main body 10 is divided into three parts: the main body receiving connector 77, the chamber side inflow path 52IN, and the chamber side outflow path 52OUT. That is, the sensor side interface and Figure 4 The main body side interface (the configuration of the main body side connector 26A, the main body side inlet 22IN, and the main body side outlet 24OUT) is completely consistent.

[0067] <Connection between main unit and gas detection module> exist Fig.11 1 shows the connection state between the main body 10 and the gas detection module 50 in the gas detector 1. The main body side interface (the configuration of the main body side connector 26A, the main body side inlet 22IN, and the main body side outlet 24OUT) is completely consistent with the sensor side interface (the main body receiving connector 77, the chamber side inlet 52IN, and the chamber side outlet 52OUT). Therefore, the two can be connected by simply pressing the gas detection module 50 into the inner side of the main body 10 in the depth direction (refer to Fig.11 (B)). On the contrary, the two can be separated by simply pulling the gas detection module 50 toward the front side in the depth direction relative to the main body 10 (refer to Fig.11 (A)).

[0068] <Circuit Structure> exist Fig. 12A The overall circuit structure of the gas detector 1 is shown in FIG.

[0069] (Main body side circuit structure) The main body side circuit substrate 26 has a main body side computer 34, a first judgment power supply unit 202, a second judgment power supply unit 204, a first base power supply unit 206, a second base power supply unit 208, a third judgment response unit 220, a heater power supply unit (additional function supply unit) 210, an external communication connector 28C, and a main body side connector 26A.

[0070] The main body side circuit board 26 includes a first determination path 102, a second determination path 104, a third determination path 116, a first base power path 106, a second base power path 108, a heater power path 110, a first communication path 112, a second communication path 118, and a reset path 114 as electric paths connected to the gas detection module 50 via the main body side connector 26A. It should be noted that the first determination path 102 and the second communication path 118 are realized by a single path.

[0071] The first determination power supply unit 202 is, for example, a 3.3V power supply and a first main body side resistor connected in series therewith, and supplies the first determination power to the gas detection module 50 via the first determination path 102. The second determination power supply unit 204 is, for example, a 3.3V power supply and a second main body side resistor connected in series therewith, and supplies the second determination power to the gas detection module 50 via the second determination path 104. The first base power supply unit 206 is, for example, a 5.0V power supply, and supplies the first base power to the gas detection module 50 via the first base power path 106. The second base power supply unit 208 is, for example, a 24V power supply, and supplies the second base power to the gas detection module 50 via the second base power path 108. The heater power supply unit (additional function supply unit) 210 is, for example, a variable voltage power supply, and supplies heater power that is variable (controlled) in the range of 1.0V to 10.0V on the main body 10 side to the gas detection module 50 via the heater power path 110.

[0072] It should be noted that, for example, the maximum supply voltage of the first determination power supply unit 202 and the second determination power supply unit 204 is set to be lower than the minimum supply voltage of the first pedestal power supply unit 206 and the second pedestal power supply unit 208, and is preferably set to be lower than the minimum supply voltage of the first pedestal power supply unit 206 and the second pedestal power supply unit 208. This is to avoid a situation where a malfunction occurs due to the determination power supplied before the determination of the gas detection module 50 exceeds the allowable voltage of the gas detection module 50.

[0073] The third determination response unit 220 is, for example, a third main body side resistor connected between the third determination path 116 and the ground (GND), and manages the voltage level of the third determination path 116. For example, the voltage level of the third determination path 116 becomes a voltage division of a third sensor side resistor and a third main body side resistor of a third determination power supply unit 706 described later. That is, if the voltage of the third determination power supply unit 706 and the resistance value of the third sensor side resistor are changed, the voltage level of the third determination path 116 can be changed.

[0074] The main body side computer 34 includes a first determination unit 34A that detects the voltage level of the first determination path 102, a second determination unit 34B that detects the voltage level of the second determination path 104, and a third determination unit 34C that detects the voltage level of the third determination path 116. Based on the voltage levels of the first determination unit 34A to the third determination unit 34C, the main body side computer 34 determines the type of the gas detection module 50.

[0075] The second communication path 118 sends (outputs) the command signal generated by the main body side computer 34 to the gas detection module 50. Therefore, the second communication path 118 is connected to the command sending unit 34D of the main body side computer 34. The second communication path 118 and the first determination path 102 merge in the main body side circuit substrate 26 to form a single path, and are connected to the main body side connector 26A. As a result, the number of pins (number of paths) of the main body side connector 26A is reduced. It should be noted that in this embodiment, except for the grounding pin GND, the number of pins of the main body side connector 26A is set to less than 10 (specifically 8). When the second communication path 118 is made functional, in the main body side computer 34, the general input setting of the first determination power based on the first determination unit 34A is switched to the communication output setting based on the command sending unit 34D.

[0076] The first communication path 112 receives (inputs) the digital signal transmitted from the gas detection module 50 via the main body side computer 34. Therefore, the first communication path 112 is connected to the signal receiving unit 34E of the main body side computer 34.

[0077] The reset path 114 transmits a reset signal generated by the main body computer 34 to the gas detection module 50. Therefore, the reset path 114 is connected to the reset transmission unit 34F of the main body computer 34. When the reset signal is released, the gas detection module 50 starts gas detection.

[0078] (Circuit structure on the base side) The base-side circuit board 73 includes a base-side computer 74 , a sensor receiving connector 75 , a main body receiving connector 77 , a first determination response unit 702 , a second determination response unit 704 , and a third determination power supply unit 706 .

[0079] The base side circuit board 73 includes a first determination path 102, a second determination path 104, a third determination path 116, a first base power path 106, a second base power path 108, a heater power path 110, a first communication path 112, a reset path 114, and a second communication path 118 as paths for electrically connecting the main body receiving connector 77 and the sensor receiving connector 75. It should be noted that the first determination path 102 and the second communication path 118 are used as a single path. It should be noted that the first communication path 112, the reset path 114, and the second communication path 118 are provided with the base side computer 74 in the middle of the path.

[0080] The first determination response unit 702 is, for example, a first response side resistor connected between the first determination path 102 and the ground (GND), and sets the voltage level of the first determination path 102. For example, when the supply voltage of the first determination power supply unit 202 is set to 3.3V, the voltage level of the first determination path 102 becomes the voltage division of the first main body side resistor and the first response side resistor in the first determination power supply unit 202. That is, when the value of the first main body side resistor is fixed, the voltage level of the first determination path 102 can be uniquely determined by the value of the first response side resistor. The voltage level is detected by the first determination unit 34A of the main body side computer 34. Therefore, if the value of the first response side resistor of the first determination response unit 702 is set to be different from the value of the first response side resistor of the first determination response unit in the gas detection module of the second embodiment and the third embodiment described later, the voltage level detected by the main body side computer 34 is different, and the type of the gas detection module 50 and / or the type of the sensor base 70 can be determined.

[0081] The second determination response unit 704 is, for example, a second response side resistor connected between the second determination path 104 and the ground (GND), and sets the voltage level of the second determination path 104. For example, when the supply voltage of the second determination power supply unit 204 is set to 3.3V, the voltage level of the second determination path 104 becomes the voltage division of the second body side resistor and the second response side resistor in the second determination power supply unit 204. That is, when the value of the second body side resistor is fixed, the voltage level of the second determination path 104 can be uniquely determined by the value of the second response side resistor. The voltage level is detected by the second determination unit 34B of the body side computer 34. Therefore, if the value of the second response side resistor of the second determination response unit 704 is set to be different from the value of the second response side resistor of the second determination response unit in the gas detection module of the second embodiment and the third embodiment described later, the voltage level detected by the body side computer 34 is also different, and the type of the gas detection module 50 and / or the type of the sensor base 70 can be determined.

[0082] Furthermore, in the main body computer 34 , by combining the voltage level of the first determination path 102 and the voltage level of the second determination path 104 , it is possible to determine the types of various gas detection modules (details will be described later).

[0083] The third determination power supply unit 706 is a 3.3V power supply using a regulator (power IC) or the like, for example, and a third sensor side resistor connected in series therewith. For example, the voltage level of the third determination path 116 is a voltage division of the third sensor side resistor and the third body side resistor of the third determination response unit 220 on the body 10 side. The voltage level of the third determination path 116 is detected by the third determination unit 34C of the body side computer 34. The voltage level of the third determination path 116 can be used to determine a special gas detection module that cannot be determined even if the voltage level of the first determination path 102 and the voltage level of the second determination path 104 are combined.

[0084] It should be noted that, in this embodiment, the first determination response unit 702 and the second determination response unit 704 are all provided on the base side circuit substrate 73, but the present invention is not limited thereto. For example, part or all of them may be provided on the sensor side circuit substrate 63 side (see Fig.13A ). In this way, even if the gas sensor 60 is replaced with another type without replacing the sensor base 70, the main body side computer 34 can determine the type of the gas sensor 60 by making the value of the first response side resistor and the value of the third response side resistor different in the different types of gas sensors 60.

[0085] The second communication path 118 extending from the main body receiving connector 77 is connected to the command receiving unit 74Din of the base side computer 74. The command received by the command receiving unit 74Din is output to the second communication path 118 connected to the command sending unit 74Dout of the base side computer 74, and is transmitted to the sensor receiving connector 75.

[0086] On the other hand, the first communication path 112 extending from the sensor receiving connector 75 is connected to the signal receiving unit 74Ein of the base side computer 74. After a predetermined process, the signal received by the command receiving unit 74Ein is output from the command sending unit 74Eout of the base side computer 74 to the first communication path 112 and transmitted to the main body receiving connector 77.

[0087] The reset path 114 extending from the main body receiving connector 77 is connected to the reset receiving unit 74Fin of the base side computer 74. The command received by the reset receiving unit 74Fin is output to the reset path 114 connected to the reset sending unit 74Fout of the base side computer 74, and is transmitted to the sensor receiving connector 75.

[0088] (Sensor side circuit structure) The sensor side circuit board 63 has a sensor side computer 64 and a sensor side connector 65. The gas detection unit 62 is connected to the sensor side circuit board 63. It should be noted that a heater unit 62H such as a noble metal coil may be built into the gas detection unit 62 depending on the gas detection method.

[0089] The sensor side circuit board 63 includes a first determination path 102, a second determination path 104, a third determination path 116, a first base power path 106, a second base power path 108, a heater power path 110, a first communication path 112, a reset path 114, and a second communication path 118 as electric paths connected to the sensor base 70 via the sensor side connector 65. It should be noted that the first determination path 102 and the second communication path 118 are used as a single path.

[0090] The second communication path 118 extending from the sensor side connector 65 is connected to the command receiving unit 64Din of the sensor side computer 64. The sensor side computer 64 outputs a desired response based on the command received by the command receiving unit 64Din from the signal sending unit 64Eout. The signal sending unit 64Eout of the sensor side computer 64 is connected to the first communication path 112. The first communication path 112 extends to the sensor side connector 65.

[0091] The reset path 114 extending from the sensor connector 65 is connected to the reset receiving section 64Fin of the sensor computer 64. Referring to the command received by the reset receiving section 64Fin, the sensor computer 64 determines whether a signal is output from the signal transmitting section 64Eout (whether communication is started).

[0092] The analog output of the gas detection unit 62 is transmitted to the analog receiving unit 64Kin of the sensor side computer 64 via the analog output path 130. The sensor side computer 64 converts the analog signal received by the analog receiving unit 64Kin into a digital signal, further standardizes it, and then outputs it from the signal transmitting unit 64Eout.

[0093] The first base power path 106 extending from the sensor side connector 65 is connected to the gas detection unit 62. Thus, the first base power is supplied to the gas detection unit 62. In addition, the second base power path 108 extending from the sensor side connector 65 is connected to the gas detection unit 62. Thus, the second base power is supplied to the gas detection unit 62. In addition, the heater power path 110 extending from the sensor side connector 65 is connected to the heater unit 62H. Thus, the heater power that has been controlled is supplied to the heater unit 62H. It should be noted that it is not necessary to supply the first base power and the second base power at the same time, and appropriate power can be selectively supplied from the first base power and the second base power according to the type of the gas sensor 60. In this case, in the base side circuit substrate 73 and / or the sensor side circuit substrate 63, any one of the first base power path 106 and the second base power path 108 can be omitted. In addition, in the case where the gas detection unit 62 is a structure without a built-in heater unit 62H, the heater power may not be supplied. In this case, the heater power path 110 in the base-side circuit board 73 and / or the sensor-side circuit board 63 can be omitted.

[0094] <Gas Detection Procedure> Next, a gas detection program (gas detection step) executed in the gas detector 1 will be described. The gas detection program is executed by the main body side computer 34 , the base side computer 74 , and the sensor side computer 64 .

[0095] exist Fig. 12B 4 shows the functions realized by the main body side computer 34, the base side computer 74, and the sensor side computer 64 by executing the gas detection program (gas detection step).

[0096] (Function of the computer on the main body) The main body side computer 34 has a judgment input processing unit 3402, a sensor judgment processing unit 3404, an auxiliary judgment input processing unit 3406, an auxiliary sensor judgment processing unit 3408, a base power supply processing unit 3410, a path function switching processing unit 3412, a control protocol switching processing unit 3414, a sensor setting information reading unit 3416, an output demultiplexing processing unit 3418, an input multiplexing processing unit 3420, and an additional function processing unit 3422.

[0097] After the main power of the main body 10 is turned on, the determination input processing unit 3402 controls the first determination power supply unit 202 and the second determination power supply unit 204 to supply the first determination power and the second determination power to the first determination path 102 and the second determination path 104 .

[0098] The sensor determination processing unit 3404 determines the gas detection module connected to the main body 10 based on the voltage level of the first determination path 102 supplied with the first determination power and the voltage level of the second determination path 104 supplied with the second determination power. It should be noted that the voltage level of the third determination path 116 may be added to the determination condition.

[0099] For example, the sensor determination processing unit 3404 refers to the Fig.14 . In the sensor determination table, if the voltage level of the first determination path 102 is determined at multiple levels (here, three levels A1 to A3), and the voltage level of the second determination path 104 is determined at multiple levels (six levels B1 to B6), then through their combination, the sensor determination processing unit 3404 can determine a total of 18 types of gas detection modules (sensor types). If the voltage level of the third determination path 116 is combined, more types can be determined.

[0100] It should be noted that in this embodiment, as the judgment input processing unit 3402, an example is given in which power is supplied and the voltage level is used for judgment, but the present invention is not limited to this. The judgment input processing unit 3402 sends a command to send the type information, and the base side computer 74 and / or the sensor side computer 64 responds with the sensor type information (response value) stored in each memory, so that the sensor judgment processing unit 3404 can also judge the type of the gas detection module.

[0101] After the sensor judgment processing unit 3404 has completed the judgment of the gas detection module (particularly the sensor base 70), the auxiliary judgment input processing unit 3406 supplies auxiliary instructions or auxiliary power (hereinafter referred to as auxiliary judgment input) for judging the detailed specifications of the gas detection module in an auxiliary manner. In particular, the auxiliary judgment input is not supplied for judging the entire gas detection module 50, but for judging the type of the gas sensor 60 mounted on the gas detection module 50. It should be noted that in this embodiment, it is assumed that the communication function has been turned on before the auxiliary judgment input processing unit 3406 is started, so the auxiliary instruction is sent to the base side computer 74 and / or the sensor side computer 64 using the second communication path 118. The auxiliary sensor judgment processing unit 3408 refers to the response value (auxiliary response value) sent from the base side computer 74 and / or the sensor side computer 64 (here, the sensor side computer 64 of the gas sensor 60) to judge the type of the gas sensor 60.

[0102] For example, in Fig.19 In the second embodiment of the present invention, in the case of a gas detection module equipped with multiple gas sensors as described later, it is necessary to perform both the judgment of the entire module (sensor base) and the individual judgment of the multiple gas sensors mounted on the module. At this time, the judgment of the entire gas detection module is preferably performed before the communication function starts, so in this embodiment, the judgment is performed by using the voltage levels of the first judgment path 102, the second judgment path 104, etc. of the judgment input processing unit 3402 and the sensor judgment processing unit 3404. On the other hand, if the judgment of the entire module (sensor base) is completed, the communication function (communication protocol) suitable for the gas detection module can be started between the main body side computer 34 and the base side computer 74, so the auxiliary judgment input processing unit 3406 and the auxiliary sensor judgment processing unit 3408 perform detailed judgment of the gas sensor by using the signal exchange of the command signal and the auxiliary response signal.

[0103] At this time, Fig.19 In the case of the gas detection module shown in FIG. 1 , since it is also possible to assume that the gas sensor is not installed or fails, the communication between the base side computer and the sensor side computer is not restricted. Fig.19As shown, the base-side computer 2074 that receives the auxiliary instruction from the main-side computer 34 supplies judgment power to, for example, the first sensor-side first judgment response unit 2707A and the first sensor-side second judgment response unit 2708A of the first sensor-side circuit substrate 2063A, and detects the response voltage level on the base-side computer 2074 side, thereby making judgments on each gas sensor, and sending the judgment results to the main-side computer 34 via the first communication path 112. Thus, the judgment of the gas sensor can be made independently of whether the sensor-side computer is started or not.

[0104] The base power supply processing unit 3410 supplies base power to the gas detection module 50. Specifically, based on the judgment result of the gas detection module 50 obtained by the sensor judgment processing unit 3404, the base power suitable for this is supplied to the gas detection module 50. At this time, the base power supply processing unit 3410 can control the voltage level of the base power, and can also selectively supply a suitable base power from a plurality of base power sources (a first base power source and a second base power source).

[0105] The path function switching processing unit 3412 switches between a mode (sensor determination mode) in which the first determination path 102 is supplied with the first determination power by the first determination power supply unit 202 so that the sensor determination can be performed using the first determination path 102, and a mode (signal transmission mode) in which the general output setting of the first determination power is changed to a communication setting so that the signal can be transmitted using the second communication path 118. Thus, a single path can be shared by both the first determination path 102 and the second communication path 118, so the number of connector pins can be reduced.

[0106] The control protocol switching processing unit 3414 switches the control protocol (control step) for controlling the gas detection module 50 based on the judgment result of the gas detection module 50 obtained by the judgment input processing unit 3402 and the sensor judgment processing unit 3404 and / or the judgment result of the auxiliary sensor judgment processing unit 3408. In this way, sensor control that matches various gas detection methods that can be adopted by the gas detection unit 62 can be realized.

[0107] The input multiplexing processing unit 3420 multiplexes the plurality of command signals generated by the main body side computer 34 and sets them as a sequence command. The sequence command is sent to the gas detection module 50 via the second communication path 118. It should be noted that the multiplexing includes multiplexing commands for a plurality of gas sensors as in the gas detection module 2050 of the second embodiment, in addition to multiplexing a plurality of command signals for a single gas sensor 60.

[0108] The output demultiplexing processing unit 3418 receives the multiplexed sequence output sent from the base-side computer 74 and distributes it as individual outputs. The output demultiplexing processing unit 3418 is preferably used in the case of receiving the multiplexed sequence output of the measurement results (outputs) of multiple gas sensors, as in the gas detection module 2050 of the second embodiment.

[0109] The additional function processing unit 3422 determines the supply level (including whether the supply is possible) of the additional function for the gas detection module 50 based on the judgment result obtained by the sensor judgment processing unit 3404 and / or the judgment result of the auxiliary sensor judgment processing unit 3408. Fig.14 The sensor determination table shown in the figure is used to control the supply level of the additional function. Specifically, the additional function processing unit 3422 controls the heater power supply unit 210 to supply the desired controlled power to the gas detection module 50. If the gas detection module 50 or the gas sensor 60 is made compact, it will be impossible to assemble the power supply for the heater and its power control function inside. Therefore, in the present embodiment, the heater power supply unit 210 is provided on the side of the main body 10 which becomes the outside of the gas detection module 50, so that the controlled power (additional power) is supplied to the gas detection module 50. When the gas detection module 50 or the gas sensor 60 is replaced due to a malfunction, the heater power supply unit 210 remains on the main body 10 side, so that the number of parts to be replaced can be reduced, thereby reducing maintenance costs.

[0110] The sensor setting information reading unit 3416 receives the request specification information sent from the request specification output processing unit 6406 included in the sensor side computer 64. The main body side computer 34 controls the voltage level of the base power and the voltage level of the heater power based on the request specification information.

[0111] (Function of the base side computer) The base side computer 74 has an input demultiplexing processing unit 7402 and an output multiplexing processing unit 7404. The input demultiplexing processing unit 7402 distributes the multiplexed sequence instructions sent from the input multiplexing processing unit 3420 of the main body side computer 34 into individual instructions. When a plurality of gas sensors are mounted as in the gas detection module 2050 of the second embodiment, the multiplexed instructions are distributed and transmitted to each gas sensor. The output multiplexing processing unit 7404 multiplexes the signals output from the plurality of gas sensors and outputs them as a sequence, as in the gas detection module 2050 of the second embodiment, and transmits them to the main body side computer 34.

[0112] (Function of the sensor-side computer) The sensor-side computer 64 includes a normalization processing unit 6402, a category output processing unit 6404, and a request specification output processing unit 6406. The normalization processing unit 6402 digitizes the analog output obtained from the gas sensor 60, and normalizes the digital output according to the output rule (output specification) preset by the main body-side computer 34. Through the normalization processing unit 6402, even when the gas sensor 60 is replaced with a different one, the main body-side computer 34 and the base-side computer 74 can process the output data without performing special processing.

[0113] The type output processing unit 6404 outputs type information (e.g., information related to the gas detection method) stored in the sensor side memory (not shown) mounted on the sensor side circuit board 63 to the main body side computer 34 as a response based on the auxiliary command sent from the auxiliary judgment input processing unit 3406 of the main body side computer 34. As a result, the auxiliary sensor judgment processing unit 3408 of the main body side computer 34 can judge the type of the gas sensor 60.

[0114] The request specification output processing unit 6406 outputs the request specification information (e.g., information on the base voltage level, the necessity and level of heater power, etc.) stored in the sensor side memory (not shown) mounted on the sensor side circuit board 63 to the main body side computer 34 as a response to the command sent from the sensor setting information reading unit 3416 of the main body side computer 34. Thus, the sensor setting information reading unit 3416 of the main body side computer 34 can acquire the setting information of the gas sensor 60.

[0115] (Flow from main power on to start of measurement) Reference Fig.15 The flowchart of the present invention is used to explain the steps performed by the gas detector 1. First, if the main power supply of the gas detector 1 is turned on in step S1002, the judgment input is turned on in step S1004. This "turning on the judgment input" means that the first judgment power supply unit 202 and the second judgment power supply unit 204 start to supply the judgment power. In step S1006, it is determined whether the gas detection module 50 can be judged. The situation where the judgment cannot be made (no) refers to any of the following situations: the gas detection module 50 is not connected, the gas detection module 50 fails, and the gas detection module other than the judgment object is connected. Therefore, the process returns to step S1004 and waits while keeping the judgment input turned on. In the case where the judgment can be made in step S1006 (yes), the process proceeds to step S1008, and the base power suitable for the judged category is supplied to the gas detection module 50.

[0116] Next, the process proceeds to step S1010 to determine whether the determined category requires an additional function (e.g., a heater function). If the additional function is required (yes), the process proceeds to step S1012, and after turning on the additional function (e.g., heater power supply), the process proceeds to step S1014. On the other hand, if the additional function is not required (no), the process skips step S1012 and proceeds to step S1014. In step S1014, in the main body side computer 34, the setting is changed from the general input state of the power supply by the first judgment power supply unit 202 in step S1004 detected by the first judgment unit 34A to the communication output state based on the command transmission unit 34D, thereby switching the first judgment path 102 to the second communication path 118. Thus, communication is ready.

[0117] Next, the process proceeds to step S1016, and by releasing the reset signal generated by the main body side computer 34, the signal communication between the main body side computer 34, the base side computer 74, and the sensor side computer 64 is started. Thereafter, in step S1018, it is determined whether further detailed determination (auxiliary determination) is required for the type of the gas detection module 50. For example, in the case of a model in which a plurality of gas sensors are mounted inside the gas detection module 50, it is determined that auxiliary determination is required (yes), and the process proceeds to step S1020, and the auxiliary determination input is turned on. It should be noted that this "turning on the auxiliary determination input" means sending an auxiliary instruction from the auxiliary determination input processing unit 3406 of the main body side computer 34. Thereafter, the process proceeds to step S1022, and the response (reply of the type information) of the sensor side computer 64 is waited. If the appropriate type information can be obtained (yes), the process proceeds to step S1024. On the other hand, if the appropriate type response cannot be obtained in step S1022 (no), the process returns to step S1020, and the auxiliary instruction is sent again. In addition, in step S1018, when it is determined that no further detailed determination (auxiliary determination) is necessary for the type of the gas detection module 50 (No), the above steps S1020 and S1022 are skipped and the process proceeds to step S1024.

[0118] In step S1024, the main body side computer 34 obtains sensor setting information (request specification information) from the sensor side computer 64, and in step S1026, based on the sensor setting information, performs detailed adjustments of the base power, heater power, etc. After the above steps, the measurement is ready, and the gas measurement starts in step S1028.

[0119] It should be noted that Fig. 12A and Fig. 12BIn the example, the case where the base-side computer 74, the first determination response unit 702, the second determination response unit 704, and the third determination power supply unit 706 are provided on the base-side circuit substrate 73 is illustrated, but the present invention is not limited thereto. Fig.13A and Fig. 13B As shown, by making the sensor side computer 64 have an input demultiplexing processing unit 7402 and an output multiplexing processing unit 7404 as the functions of the base side computer 74, the base side computer 74 can be omitted. Similarly, the first determination response unit 702, the second determination response unit 704, and the third determination power supply unit 706 can also be mounted on the sensor side circuit substrate 63. In this way, the base side circuit substrate 73 can be set as a relay substrate for the main body side connector 26A and the sensor side connector 65. If the number of pins of the main body side connector 26A and the sensor side connector 65 is different, the difference in the number of pins can also be eliminated by the base side circuit substrate 73.

[0120] <Second Embodiment> Next, refer to Fig.16 The following drawings illustrate the gas detector 2001 of the second embodiment. The main body 10 of the gas detector 2001 is the same as that of the first embodiment, so the description is omitted. In the gas detection module 2050 connected to the main body 10 in a detachable manner, the difference from the gas detection module 50 of the first embodiment is described. For the parts, components, etc. that are the same or similar to each other between the gas detection module 2050 and the gas detection module 50, the detailed description is omitted by making the last three digits of the symbol consistent.

[0121] <Gas detection module> exist Fig.16 and Fig.17 2050 shows the overall structure of the gas detection module 2050. The gas detection module 2050 includes a chamber 2052, a first gas sensor 2060A, a second gas sensor 2060B, and a sensor base 2070.

[0122] (Chamber) The chamber 2052 has a chamber side inflow passage 2052IN of a male structure (protruding structure) connected to the main body side inflow inlet 22IN in a detachable manner, a chamber side outflow passage 2052OUT of a male structure (protruding structure) connected to the main body side outflow outlet 24OUT in a detachable manner, and a first internal space 2054A and a second internal space 2054B between the chamber side inflow passage 2052IN and the chamber side outflow passage 2052OUT. The first internal space 2054A is a cylindrical space having a bottom surface, and its annular protruding end is a first sensor insertion port 2058A. The chamber side inflow passage 2052IN and the chamber side outflow passage 2052OUT are connected to each other on the bottom surface of the first internal space 2054A. A rubber-like sealing ring is provided at the first sensor insertion port 2058A. The first sensor insertion port 2058A (seal ring) is brought into contact with the first sealing surface 2068A, which is an annular tapered surface of the first gas sensor 2060A, so that the first internal space 2054A becomes a closed space.

[0123] The second internal space 2054B is arranged side by side with the first internal space 2052A in the vertical direction. The second internal space 2054B is a cylindrical space with a bottom surface, and its annular protruding end becomes the second sensor insertion port 2058B. The bottom surface of the second internal space 2054B is connected with the chamber side inflow path 2052IN and the chamber side outflow path 2052OUT. That is, the chamber side inflow path 2052IN and the chamber side outflow path 2052OUT are connected to both the first internal space 2052A and the second internal space 2054B by branching off from each other. A rubber-like sealing ring is provided at the second sensor insertion port 2058B. The second internal space 2054B becomes a closed space by bringing the second sensor insertion port 2058B (sealing ring) into contact with the second sealing surface 2068B, which becomes an annular conical surface, of the second gas sensor 2060B.

[0124] The cavity 2052 has a pair of cavity side engaging parts 2055 in the form of elastic claw structures. The cavity side engaging parts 2055 are engaged with the base side engaging parts 2079 in the form of a pair of receiving groove structures on the sensor base 2070 side, so that the cavity 2052 and the sensor base 2070 are connected to each other.

[0125] (First gas sensor) like Fig.16As shown in (B), the first gas sensor 2060A includes a first sensor housing 2061A, a first gas detection unit 2062A, a first sensor side circuit board 2063A, a first sensor side computer 2064A and a first sensor side memory (not shown) mounted on the first sensor side circuit board 2063A, and a first sensor side connector 2065A mounted on the first sensor side circuit board 2063A. Fig.17 As shown in (A), a first sealing surface 2068A is formed around the first sensor housing 2061A. The first sensor insertion port 2058A (seal ring) of the chamber 2052 contacts the first sealing surface 2068A, thereby forming a closed space in the first internal space 2054A on the first gas detection unit 2062A side.

[0126] The first sensor side computer 2064A converts the analog response of the first gas detection unit 2062A into a digital signal and outputs it. The first sensor side computer 2064A further standardizes the digital signal of the first gas detection unit 2062A and outputs it. In addition, the first sensor side computer 2064A outputs the first category information and the first setting information stored in the first sensor side memory itself. The first sensor side computer 2064A receives the command signal sent from the main body side computer 34 or the base side computer 2074, and outputs a response signal based on the command.

[0127] The first sensor side connector 2065A is detachably connected to the first sensor receiving connector 2075A of the sensor base 2070. The first gas sensor 2060A is fixed to the sensor base 2070 via the first sensor side connector 2065A.

[0128] (Second gas sensor) like Fig.16 As shown in (B), the second gas sensor 2060B includes a second sensor housing 2061B, a second gas detection unit 2062B, a second sensor side circuit board 2063B, a second sensor side computer 2064B mounted on the second sensor side circuit board 2063B, a second sensor side memory (not shown), and a second sensor side connector 2065B mounted on the second sensor side circuit board 2063B. Fig.17 As shown in (A), a second sealing surface 2068B is formed around the second sensor housing 2061B. The second sensor insertion port 2058B (seal ring) of the chamber 2052 contacts the second sealing surface 2068B, thereby forming a closed space in the second internal space 2054B on the second gas detection unit 2062B side.

[0129] The second sensor side computer 2064B converts the analog response of the second gas detection unit 2062B into a digital signal and outputs it. The second sensor side computer 2064B further standardizes the digital signal of the second gas detection unit 2062B and outputs it. In addition, the second sensor side computer 2064B outputs the second category information and the second setting information stored in the second sensor side memory itself. The second sensor side computer 2064B receives the command signal sent from the main body side computer 34 or the base side computer 2074, and outputs a response signal based on the command.

[0130] The second sensor side connector 2065B is detachably connected to the second sensor receiving connector 2075B of the sensor base 2070. The second gas sensor 2060B is fixed to the sensor base 2070 via the second sensor side connector 2065B.

[0131] (Sensor base) like Fig.16 As shown in (B), the sensor base 2070 has a base shell 2071, a base side circuit substrate 2073, a base side computer 2074 and a base side memory (not shown) mounted on the base side circuit substrate 2073, a first sensor receiving connector 2075A and a second sensor receiving connector 2075B mounted on the base side circuit substrate 2073, and a main body receiving connector 2077 mounted on the base side circuit substrate 2073.

[0132] like Fig.17 As shown, the base housing 2071 is a rectangular parallelepiped housing, and the base side circuit substrate 2073 is stored inside. In the base housing 2071, a circular first sensor insertion opening 2071A is formed at a position corresponding to the first sensor receiving connector 2075A, and as a result, the entire first sensor receiving connector 2075A and a part of the base side circuit substrate 2073 are exposed to the outside. In the base housing 2071, a circular second sensor insertion opening 2071B is formed at a position corresponding to the second sensor receiving connector 2075B, and as a result, the entire second sensor receiving connector 2075B and a part of the base side circuit substrate 2073 are exposed to the outside.

[0133] The first gas sensor 2060A is inserted through the first sensor insertion opening 2071A, thereby connecting the first sensor receiving connector 2075A to the first sensor side connector 2065A. Similarly, the second gas sensor 2060B is inserted through the second sensor insertion opening 2071B, thereby connecting the second sensor receiving connector 2075B to the second sensor side connector 2065B.

[0134] The base-side computer 2074 multiplexes the standardized digital signals received from both the first gas sensor 2060A and the second gas sensor 2060B, and transmits them as a serial signal to the main body-side computer 34. It should be noted that, assuming that at least one of the first gas sensor 2060A and the second gas sensor 2060B is not equipped with a sensor-side computer, the base-side computer 2074 can also digitize or standardize the analog signal of the gas detection unit. In addition, the base-side computer 2074 can output the category information and various setting information stored in the base-side memory itself to the main body-side computer 34.

[0135] (Sensor side interface for the main body) like Fig.16 As shown in (C), the sensor side interface for connecting the gas detection module 2050 to the main body 10 is divided into three parts: the main body receiving connector 2077, the chamber side inflow path 2052IN, and the chamber side outflow path 2052OUT. That is, the sensor side interface and Figure 4 The main body side interface (the configuration of the main body side connector 26A, the main body side inlet 22IN, and the main body side outlet 24OUT), the sensor side interface ( Fig. 9 (C) is completely consistent.

[0136] <Connection between main unit and gas detection module> exist Fig.18 2001 shows the connection state between the main body 10 and the gas detection module 2050 in the gas detector 2001. The main body side interface (the configuration of the main body side connector 26A, the main body side inlet 22IN, and the main body side outlet 24OUT) is completely consistent with the sensor side interface (the main body receiving connector 2077, the chamber side inlet 2052IN, and the chamber side outlet 2052OUT). Therefore, the two are connected by simply pressing the gas detection module 2050 into the inner side of the main body 10 in the depth direction (refer to Fig.18 (B)). On the contrary, the two can be separated by simply pulling the gas detection module 2050 toward the front side in the depth direction relative to the main body 10 (refer to Fig.18 (A)).

[0137] <Circuit Structure> exist Fig.19 The overall circuit structure of the gas detector 2001 is shown in FIG.

[0138] (Base side circuit configuration) The base side circuit board 2073 has a base side computer 2074, a first sensor receiving connector 2075A, a second sensor receiving connector 2075B, a main body receiving connector 2077, a first judgment response unit 2702, a second judgment response unit 2704, and a third judgment power supply unit 2706.

[0139] The base side circuit board 2073 has a first base power path 106, a second base power path 108, and a heater power path 110 as paths for electrically connecting the main body receiving connector 2077 to the first sensor receiving connector 2075A and electrically connecting the main body receiving connector 2077 to the second sensor receiving connector 2075B. The first base power path 106 extending from the main body receiving connector 2077 branches into a first base power path 106A for the first sensor and a first base power path 106B for the second sensor, respectively connected to the first sensor receiving connector 2075A and the second sensor receiving connector 2075B. The second base power path 108 extending from the main body receiving connector 2077 branches into a second base power path 108A for the first sensor and a second base power path 108B for the second sensor, respectively connected to the first sensor receiving connector 2075A and the second sensor receiving connector 2075B. The heater power path 110 extending from the body receiving connector 2077 branches into a first sensor heater power path 110A and a second sensor heater power path 110B, which are connected to the first sensor receiving connector 2075A and the second sensor receiving connector 2075B, respectively.

[0140] The base side circuit board 2073 further includes a first determination path 102, a second determination path 104, and a third determination path 116 as electrical paths connected to the main body receiving connector 2077. A first determination response unit 2702 is connected to the first determination path 102, a second determination response unit 2704 is connected to the second determination path 104, and a third determination power supply unit 2706 is connected to the third determination path 116.

[0141] The base-side circuit board 2073 includes a first communication path 112 , a reset path 114 , and a second communication path 118 as signal transmission paths extending from the main body receiving connector 2077 to the base-side computer 2074 .

[0142] The base side circuit board 2073 includes a first communication path 112A and a first reset path 114A on one side, a second communication path 118A on one side, a first sensor side first determination path 120A, and a first sensor side second determination path 121A as communication paths extending from the base side computer 2074 to the first sensor receiving connector 2075A. The base side circuit board 2073 includes a first communication path 112B and a second reset path 114B on the other side, a second communication path 118B and a second sensor side first determination path 120B, and a second sensor side second determination path 121B on the other side as communication paths extending from the base side computer 2074 to the second sensor receiving connector 2075B.

[0143] As a result of the above, the second communication path 118 extending from the main body receiving connector 2077 is branched into the second communication path 118A on one side and the second communication path 118B on the other side in the base side computer 2074, and extends to the first sensor receiving connector 2075A and the second sensor receiving connector 2075B. Thus, for the multiplexed sequence command received by the base side computer 2074 from the main body side computer 34, the command is separated in the base side computer 2074 and distributed to the second communication path 118A on one side and the second communication path 118B on the other side.

[0144] On the other hand, the first communication path 112A on one side extending from the first sensor receiving connector 2075A and the first communication path 112B on the other side extending from the second sensor receiving connector 2075B merge with the first communication path 112 in the base-side computer 2074 and extend to the main body receiving connector 2077. Thus, the standardized output signals (measurement results) received from the first gas sensor 2060A and the second gas sensor 2060B are multiplexed in the base-side computer 2074 and transmitted to the first communication path 112.

[0145] In addition, the reset path 114 extending from the main body receiving connector 2077 is branched into a first reset path 114A and a second reset path 114B in the base side computer 2074, and extends to the first sensor receiving connector 2075A and the second sensor receiving connector 2075B. Thus, the reset signal sent from the main body side computer 34 is distributed and sent to the first reset path 114A and the second reset path 114B.

[0146] (First sensor side circuit structure) The first sensor side circuit board 2063A has a first sensor side computer 2064A, a first sensor side connector 2065A, a first sensor side first determination response unit 2707A, and a first sensor side second determination response unit 2708A. In addition, the first gas detection unit 2062A is connected to the first sensor side circuit board 2063A. It should be noted that a first heater unit 2062A_H such as a noble metal coil may be built into the first gas detection unit 2062A.

[0147] The first sensor side circuit substrate 2063A has a first base power path 106A for the first sensor, a second base power path 108A for the first sensor, a power path 110A for the heater for the first sensor, a first communication path 112A on one side, a first reset path 114A, a second communication path 118A on one side, a first sensor side first judgment path 120A, and a first sensor side second judgment path 121A as electrical paths connected to the sensor base 2070 via the first sensor side connector 2065A.

[0148] The base-side computer 2074 supplies the first sensor-side first determination power to the first sensor-side first determination response unit 2707A of the first gas sensor 2060A via the first sensor-side first determination path 120A. In addition, the base-side computer 2074 supplies the first sensor-side second determination power to the first sensor-side second determination response unit 2708A of the first gas sensor 2060A via the first sensor-side second determination path 121A.

[0149] The base-side computer 2074 includes a first sensor-side first determination unit (not shown) that detects a voltage level of the first sensor-side first determination path 120A and a first sensor-side second determination unit (not shown) that detects a voltage level of the first sensor-side second determination path 121A.

[0150] The first sensor side first determination response unit 2707A is, for example, a first sensor side first response side resistor connected between the first sensor side first determination path 120A and the ground (GND), and sets the voltage level of the first sensor side first determination path 120A. For example, when the voltage supplied from the base side computer 2074 is set to 3.3V, the voltage level of the first sensor side first determination path 120A becomes the voltage divided by the first base side resistor and the first sensor first response side resistor in the base side computer 2074. That is, when the value of the first base side resistor is fixed, the voltage level of the first sensor side first determination path 120A can be uniquely determined by the value of the first sensor first response side resistor. The voltage level is detected by the first sensor side first determination unit of the base side computer 2074. Therefore, by appropriately setting the value of the first sensor first response side resistor of the first judgment response unit 2707A on the first sensor side, it is possible to determine whether the first gas sensor 2060A is connected and the type of the first gas sensor 2060A (including the type of a dummy gas sensor mounted for testing).

[0151] The determination result of the type, existence, etc. of the first gas sensor 2060A obtained by the base-side computer 2074 is sent to the main-body-side computer 34 via the first communication path 112 as a digital signal.

[0152] The first sensor side second determination response unit 2708A is, for example, a first sensor side second response side resistor connected between the first sensor side second determination path 121A and the ground (GND), and sets the voltage level of the first sensor side second determination path 121A. For example, when the voltage supplied from the base side computer 2074 is set to 3.3V, the voltage level of the first sensor side second determination path 121A becomes the voltage divided by the first base side resistor and the first sensor second response side resistor in the base side computer 2074. That is, when the value of the first base side resistor is fixed, the voltage level of the first sensor side second determination path 121A can be uniquely determined by the value of the first sensor second response side resistor. The voltage level is detected by the first sensor side second determination unit of the base side computer 2074. Therefore, by appropriately setting the value of the first sensor second response side resistor of the second judgment response unit 2708A on the first sensor side, it is possible to determine whether the first gas sensor 2060A is connected and the type of the first gas sensor 2060A (including the type of a dummy gas sensor mounted for testing).

[0153] The determination result of the type, existence, etc. of the first gas sensor 2060A obtained by the base-side computer 2074 is sent to the main-body-side computer 34 via the first communication path 112 as a digital signal.

[0154] The analog output of the first gas detection unit 2062A is transmitted to the first sensor side computer 2064A via the first analog output path 2130A. The first sensor side computer 2064A converts the received analog signal into a digital signal, further standardizes it, and then outputs it from one of the first communication paths 112A.

[0155] The first sensor first base power path 106A and the first sensor second base power path 108A extending from the first sensor side connector 2065A are connected to the first gas detection unit 2062A. Thus, the first base power and / or the second base power are supplied to the first gas detection unit 2062A. In addition, the first sensor heater power path 110A extending from the first sensor side connector 2065A is connected to the first heater unit 2062A_H. Thus, the heater power is supplied to the first heater unit 2062A_H.

[0156] (Second sensor side circuit structure) The second sensor side circuit substrate 2063B has a second sensor side computer 2064B, a second sensor side connector 2065B, a second sensor side first determination response unit 2707B, and a second sensor side second determination response unit 2708B. In addition, the second gas detection unit 2062B is connected to the second sensor side circuit substrate 2063B. It should be noted that a second heater unit 2062B_H such as a noble metal coil may be built into the second gas detection unit 2062B.

[0157] The second sensor side circuit substrate 2063B has a first base power path 106B for the second sensor, a second base power path 108B for the second sensor, a power path 110B for the heater for the second sensor, a first communication path 112B on the other side, a second reset path 114B, a second communication path 118B on the other side, a first judgment path 120B on the second sensor side, and a second judgment path 121B on the second sensor side as electrical paths connected to the sensor base 2070 via the second sensor side connector 2065B.

[0158] The base-side computer 2074 supplies the second sensor-side first determination power to the second sensor-side first determination response unit 2707B of the second gas sensor 2060B via the second sensor-side first determination path 120B. In addition, the base-side computer 2074 supplies the second sensor-side second determination power to the second sensor-side second determination response unit 2708B of the second gas sensor 2060B via the second sensor-side second determination path 121B.

[0159] The base-side computer 2074 includes a second sensor-side first determination unit (not shown) that detects a voltage level of the second sensor-side first determination path 120B and a second sensor-side second determination unit (not shown) that detects a voltage level of the second sensor-side second determination path 121B.

[0160] The second sensor side first determination response unit 2707B is, for example, a second sensor side first response side resistor connected between the second sensor side first determination path 120B and the ground (GND), and sets the voltage level of the second sensor side first determination path 120B. For example, when the voltage supplied from the base side computer 2074 is set to 3.3V, the voltage level of the second sensor side first determination path 120B becomes the voltage division of the second base side resistor and the second sensor first response side resistor in the base side computer 2074. That is, when the value of the second base side resistor is fixed, the voltage level of the second sensor side first determination path 120B can be uniquely determined by the value of the second sensor first response side resistor. The voltage level is detected by the second sensor side first determination unit of the base side computer 2074. Therefore, by appropriately setting the value of the second sensor first response side resistor of the second sensor side first judgment response unit 2707B, it is possible to determine whether the second gas sensor 2060B is connected and the type of the second gas sensor 2060B (including the type of a dummy gas sensor mounted for testing).

[0161] The determination result of the type, existence, etc. of the second gas sensor 2060B obtained by the base-side computer 2074 is sent to the main-body-side computer 34 via the first communication path 112 as a digital signal.

[0162] The second sensor side second determination response unit 2708B is, for example, a second sensor side second response side resistor connected between the second sensor side second determination path 121B and the ground (GND), and sets the voltage level of the second sensor side second determination path 121B. For example, when the voltage supplied from the base side computer 2074 is set to 3.3V, the voltage level of the second sensor side second determination path 121B becomes the voltage divided by the second base side resistor and the second sensor second response side resistor in the base side computer 2074. That is, when the value of the second base side resistor is fixed, the voltage level of the second sensor side second determination path 121B can be uniquely determined by the value of the second sensor second response side resistor. The voltage level is detected by the second sensor side second determination unit of the base side computer 2074. Therefore, by appropriately setting the value of the second sensor second response side resistor of the second sensor side second judgment response unit 2708B, it is possible to determine whether the second gas sensor 2060B is connected and the type of the second gas sensor 2060B (including the type of a dummy gas sensor mounted for testing).

[0163] The determination result of the type, existence, etc. of the second gas sensor 2060B obtained by the base-side computer 2074 is sent to the main-body-side computer 34 via the first communication path 112 as a digital signal.

[0164] In this embodiment, the base-side computer 2074 preferably refers to the data stored in its own memory. Fig. 27 The sensor determination table shown in FIG. 2074 is used to determine the gas sensor. In the sensor determination table, the voltage level of the first sensor side first determination path 120A or the second sensor side first determination path 120B is determined in multiple levels (here, three levels A1 to A3), and the voltage level of the first sensor side second determination path 121A or the second sensor side second determination path 121B is determined in multiple levels (six levels B1 to B6). As a result, through the combination of these, the base side computer 2074 can determine a total of 18 types of gas sensors.

[0165] In this way, by duplicating the type determination of the sensor base 2070 by the main body side computer 34 using the first determination response unit 2702 and the second determination response unit 2704 of the base side circuit board 2073, and the type determination of the first gas sensor 2060A and the second gas sensor 2060B by the base side computer 2074 using the first sensor side first determination response unit 2707A, the first sensor side second determination response unit 2708A, the second sensor side first determination response unit 2707B, the second sensor side second determination response unit 2708B, etc., it is possible to detect separately whether the first gas sensor 2060A and / or the second gas sensor 2060B is forgotten to be installed, or whether it is faulty. In addition, the determination result obtained by the base side computer 2074 is converted into a digital signal by the base side computer 2074 and transmitted via the first communication path 112, so that the increase in the number of pins of the main body receiving connector 2077 can be suppressed.

[0166] The analog output of the second gas detection unit 2062B is transmitted to the second sensor side computer 2064B via the second analog output path 2130B. The second sensor side computer 2064B converts the received analog signal into a digital signal, further standardizes it, and then outputs it from the other side first communication path 112B.

[0167] The second sensor first base power path 106B and the second sensor second base power path 108B extending from the second sensor side connector 2065B are connected to the second gas detection unit 2062B. Thus, the first base power and / or the second base power are supplied to the second gas detection unit 2062B. In addition, the second sensor heater power path 110B extending from the second sensor side connector 2065B is connected to the second heater unit 2062B_H. Thus, the heater power is supplied to the second heater unit 2062B_H.

[0168] (Number of pins on the connector) In the present embodiment, the number of pins (number of paths) of the first sensor side connector 2065A is 8, and the number of pins of the second sensor side connector 2065B is 8, totaling 16, except for the ground pin GND. On the other hand, the number of pins (number of paths) of the main body side connector 26A is 8, except for the ground pin GND. That is, the total number of pins of the main body side connector 26A connecting the sensor base 2070 to the main body 10 is set to be smaller than the total number of pins of the first gas sensor 2060A and the second gas sensor 2060B. As a result, the main body side connector 26A can be made compact. The number of pins of the main body side connector 26A is reduced by multiplexing / demultiplexing processing of commands and output signals and function switching processing of a single path.

[0169] <Gas Detection Procedure> exist Fig. 20 2 shows the functions implemented by the main body side computer 34, the base side computer 2074, the first sensor side computer 2064A, and the second sensor side computer 2064B in the gas detector 2001 by executing the gas detection program (gas detection step). It should be noted that the functional structure of the main body side computer 34 and the base side computer 2074 is the same as that of the first embodiment, so the description is omitted.

[0170] (Function of the first sensor side computer) The first sensor-side computer 2064A includes a first normalization processing unit 6402A, a first type output processing unit 6404A, and a first request specification output processing unit 6406A. The first normalization processing unit 6402A digitizes the analog output acquired from the first gas sensor 2060A and normalizes the digital output according to the output rule (output specification) preset by the main body-side computer 34.

[0171] The first category output processing unit 6404A outputs the first category information (for example, information related to the gas detection method of the first gas sensor) stored in the sensor side memory (not shown) mounted on the first sensor side circuit substrate 2063A to the main body side computer 34 as a response to the auxiliary instruction sent from the auxiliary judgment input processing unit 3406 of the main body side computer 34.

[0172] The first request specification output processing unit 6406A outputs the first request specification information (e.g., information on the base voltage level of the first gas sensor, the necessity and level of heater power, etc.) stored in the sensor side memory (not shown) mounted on the first sensor side circuit board 2063A to the main body side computer 34 as a response to the command sent from the sensor setting information reading unit 3416 of the main body side computer 34. As a result, the sensor setting information reading unit 3416 of the main body side computer 34 can acquire the setting information of the first gas sensor 2060A.

[0173] (Function of the second sensor side computer) The second sensor-side computer 2064B includes a second normalization processing unit 6402B, a second type output processing unit 6404B, and a second request specification output processing unit 6406B. The second normalization processing unit 6402B digitizes the analog output acquired from the second gas sensor 2060B and normalizes the digital output according to the output rule (output specification) preset by the main body-side computer 34.

[0174] The second category output processing unit 6404B outputs second category information (e.g., information related to the gas detection method of the second gas sensor) stored in a sensor side memory (not shown) mounted on the second sensor side circuit substrate 2063B to the main side computer 34 as a response to an auxiliary instruction sent from the auxiliary judgment input processing unit 3406 of the main side computer 34.

[0175] The second request specification output processing unit 6406B outputs the second request specification information (e.g., information on the base voltage level of the second gas sensor, the necessity and level of heater power, etc.) stored in the sensor side memory (not shown) mounted on the second sensor side circuit board 2063B to the main body side computer 34 as a response to the command sent from the sensor setting information reading unit 3416 of the main body side computer 34. As a result, the sensor setting information reading unit 3416 of the main body side computer 34 can acquire the setting information of the second gas sensor 2060B.

[0176] (Function of the base side computer) The input demultiplexing processing unit 7402 of the base-side computer 2074 distributes the multiplexed sequence command sent from the input multiplexing processing unit 3420 of the main-side computer 34 to the first sensor-side computer 2064A and the second sensor-side computer 2064B. The output multiplexing processing unit 7404 of the base-side computer 2074 multiplexes the standardized measurement result received from the first sensor-side computer 2064A and the standardized measurement result received from the second sensor-side computer 2064B as a sequence output, and transmits it to the main-side computer 34. With these structures, the main-side computer 34 can simultaneously control the multiple gas sensors 2060A and 2060B built into the gas detection module 2050.

[0177] (Flow from main power on to start of measurement) The flow from turning on the main power supply to starting the measurement in the second embodiment is similar to that in the first embodiment. Fig.15 The steps described in the flowchart are the same, so the description here is omitted.

[0178] <Third Embodiment> Reference Fig.21 The following drawings illustrate the gas detector 3001 of the third embodiment. The main body 10 of the gas detector 3001 is the same as that of the first embodiment, so the description is omitted. Here, with respect to the gas detection module 3050 connected to the main body 10 in a detachable manner, the difference from the gas detection module 50 of the first embodiment is mainly described. For the same or similar parts, components, etc. between the gas detection module 3050 and the gas detection module 50, the detailed description is omitted by making the last three digits of the symbol consistent.

[0179] <Gas detection module> Gas detection module 3050 has Fig.21 The chamber 3052 shown, and Fig. 22 Sensor unit 3080 is shown. Chamber 3052 and sensor unit 3080 are separable from each other.

[0180] (Chamber) like Fig.21As shown, the chamber 3052 has a chamber side inflow path 3052IN of a male structure (protruding structure) connected to the main body side inflow inlet 22IN in a detachable manner, a chamber side outflow path 3052OUT of a male structure (protruding structure) connected to the main body side outflow outlet 24OUT in a detachable manner, and an internal space 3054 between the chamber side inflow path 3052IN and the chamber side outflow path 3052OUT. The internal space 3054 is a cylindrical (disk-shaped) space with a bottom surface, and the annular edge of the cylinder becomes a unit insertion port 3058. A connecting convex portion 3061A (described later) of the sensor unit 3080 is inserted into the unit insertion port 3058. The chamber side inflow path 3052IN and the chamber side outflow path 3052OUT are connected to the bottom surface of the internal space 3054. A rubber-like sealing ring is provided at the unit insertion port 3058. The unit insertion port 3058 (seal ring) is brought into contact with the periphery of a connecting protrusion 3061A (described later) of the sensor unit 3080 , so that the internal space 3054 becomes a closed space.

[0181] The chamber 3052 has an elastic portion 3059 that protrudes in a U-shape toward the inner side in the depth direction in the installation posture to the main body 10. The elastic portion 3059 can be elastically displaced in the vertical direction. The elastic portion 3059 has a chamber side engaging portion 3055 that is a claw structure.

[0182] By connecting the chamber side inflow passage 3052IN to the main body side inflow inlet 22IN and the chamber side outflow passage 3052OUT to the main body side outflow outlet 24OUT, the chamber side engaging portion 3055 is connected to the main body side engaging portion 49 (see Fig.24A , Fig. 24B , Fig.24C ) are engaged to fix the chamber 3052 to the main body 10.

[0183] (Sensor unit) like Fig. 22 As shown, the sensor unit 3080 includes a unit housing 3081, a gas sensor 3060, a main body receiving connector 3077 provided on the unit housing 3081, a unit side circuit substrate 3073, a unit side computer 3074 and a unit side memory (not shown).

[0184] The unit housing 3081 is a rectangular parallelepiped housing, and contains the gas sensor 3060, the unit side circuit board 3073, the unit side computer 3074, etc. The gas sensor 3060 is directly electrically connected to the unit side circuit board 3073 in the unit housing 3081. As a result, the sensor unit 3080 has a specification that makes it impossible to replace only the gas sensor 3060 in a freely detachable manner.

[0185] The gas sensor 3060 is also formed with a cylindrically protruding connection convex portion 3061A. The end surface of the connection convex portion 3061A serves as a detection surface of the gas sensor 3060. A plurality of (four in this case) vent holes 3061B for sucking gas into the gas sensor 3060 are formed on the end surface. On the other hand, the unit housing 3081 is formed with an opening 3081A for exposing and protruding the connection convex portion 3061A of the gas sensor 3060 to the outside. By inserting the connection convex portion 3061A of the gas sensor 3060 protruding from the opening 3081A into the unit insertion port 3058 of the chamber 3052, the internal space 3054 of the chamber 3052 becomes a closed space.

[0186] It should be noted that in this embodiment, the connection convex portion 3061A that is a part of the housing of the gas sensor 3060 and the unit housing 3081 are different components, but the present invention is not limited to this. The unit housing 3081 itself may also serve as a part of the housing of the gas sensor 3060. To explain from another point of view, if the sensor unit 3080 is viewed as a whole, it means that the connection convex portion 3061A of the gas sensor 3060 also serves as a part of the unit housing 3081.

[0187] The unit-side computer 3074 is mounted on the unit-side circuit board 3073. The unit-side computer 3074 converts the analog response output from the gas sensor 3060 into a digital signal and outputs it. The unit-side computer 3074 further standardizes the digital signal. In addition, the unit-side computer 3074 outputs the category information and setting information stored in the unit-side memory itself. The unit-side computer 3074 receives the command signal sent from the main body-side computer 34 and outputs a response signal based on the command.

[0188] It should be noted that, although not specifically illustrated here, when a plurality of gas sensors are built into the unit housing 3081, the unit side computer 3074 can also multiplex the standardized digital signals from each gas sensor and transmit them to the main body side computer 34 as a serial signal.

[0189] In the unit case 3081 , a rectangular main body connection opening 3081Z is formed at a portion of the unit-side circuit substrate 3073 corresponding to the main body receiving connector 3077 , so that the main body receiving connector 3077 is exposed.

[0190] (Sensor side interface for the main body) exist Fig.233050 for connecting the sensor unit 3080 to the chamber 3052 is shown in FIG. The configuration of the sensor side interface for connecting the gas detection module 3050 to the main body 10 is divided by the main body receiving connector 3077, the chamber side inflow path 3052IN, and the chamber side outflow path 3052OUT. That is, the sensor side interface is connected to the main body 10. Figure 4 The main body side interface (configuration of the main body side connector 26A, the main body side inlet 22IN, and the main body side outlet 24OUT), the sensor side interface of the gas detection module 50 of the first embodiment, and the sensor side interface of the gas detection module 2050 of the second embodiment are completely consistent.

[0191] <Connection between main unit and gas detection module> exist Fig.24A , Fig. 24B , Fig.24C The connection state between the main body 10 and the gas detection module 3050 in the gas detector 3001 is shown in FIG. The main body side interface (the configuration of the main body side connector 26A, the main body side inlet 22IN, and the main body side outlet 24OUT) is completely consistent with the sensor side interface (the main body receiving connector 3077, the chamber side inlet 3052IN, and the chamber side outlet 3052OUT). Fig. 24B As shown, first, the chamber 3052 is connected to the main body 10. At this time, the chamber 3052 is fixed to the main body 10 by engaging the chamber side engaging portion 3055 with the main body side engaging portion 49 on the main body 10 side.

[0192] Afterwards, if Fig.24C As shown, the sensor unit 3080 is installed by pressing the sensor unit 3080 toward the inner side in the depth direction relative to the main body 10 and the chamber 3052 that are integrated with each other. Conversely, the sensor unit 3080 is separated by simply pulling the sensor unit 3080 toward the front side in the depth direction relative to the main body 10 and the chamber 3052 (see Fig. 24B ). In this way, when replacing with another sensor unit 3080 with a different gas detection method, it is possible to easily remove only the sensor unit 3080 while leaving the chamber 3052 on the side of the main body 10. It should be noted that when replacing with the gas detection module 50 of the first embodiment or the gas detection module 2050 of the second embodiment, the chamber 3052 can be removed from the main body 10 by deforming the elastic portion 3059 to release the engagement between the chamber side engaging portion 3055 and the main body side engaging portion 49.

[0193] <Circuit Structure> exist Fig.25 The overall circuit structure of the gas detector 3001 is shown in FIG.

[0194] (Unit side circuit structure) The unit-side circuit board 3073 includes a unit-side computer 3074 , a main body receiving connector 3077 , a first determination response unit 3702 , a second determination response unit 3704 , and a third determination power supply unit 3706 .

[0195] The unit side circuit substrate 3073 has a first base power path 106 and a second base power path 108 as paths for electrically connecting the main body receiving connector 3077 to the gas sensor 3060. Thus, the first base power and / or the second base power are supplied to the gas sensor 3060. It should be noted that the unit side circuit substrate 3073 has a heater power path 108X using the second base power path 108, and the heater power is controlled by the heater internal control unit 3090. The heater power is supplied to the heater part 3062H such as the noble metal coil. Therefore, the power supply by the heater power supply unit 210 in the main body side circuit substrate 26 is stopped.

[0196] The unit-side circuit board 3073 further includes a first determination path 102, a second determination path 104, and a third determination path 116 as electrical paths connected to the main body receiving connector 3077. A first determination response unit 3702 is connected to the first determination path 102, a second determination response unit 3704 is connected to the second determination path 104, and a third determination power supply unit 3706 is connected to the third determination path 116.

[0197] The unit-side circuit board 3073 includes a first communication path 112 , a reset path 114 , and a second communication path 118 as signal transmission paths extending from the main body receiving connector 3077 to the unit-side computer 3074 .

[0198] The analog output output from the gas sensor 3060 is transmitted to the unit-side computer 3074 via the analog output path 3130. The unit-side computer 3074 converts the received analog signal into a digital signal, and outputs it from the first communication path 112 after standardizing it.

[0199] <Gas Detection Procedure> exist Fig.26 2 shows the functions implemented by the main body computer 34 and the unit side computer 3074 in the gas detector 3001 by executing the gas detection program (gas detection step). The functional configuration of the main body computer 34 is the same as that of the first embodiment, and thus the description thereof is omitted.

[0200] (Function of the unit-side computer) The unit-side computer 3074 includes a normalization processing unit 7410, a category output processing unit 7406, and a request specification output processing unit 7408. The normalization processing unit 7410 digitizes the analog output acquired from the gas sensor 3060 and normalizes the digital output according to the output rule (output specification) preset by the main body-side computer 34.

[0201] The category output processing unit 7406 outputs category information (e.g., information related to the gas detection method of the gas sensor) stored in a unit side memory (not shown) mounted on the unit side circuit substrate 3073 to the main side computer 34 as a response to an auxiliary instruction sent from the auxiliary judgment input processing unit 3406 of the main side computer 34.

[0202] The request specification output processing unit 7408 outputs the request specification information (e.g., the base voltage level of the gas sensor, information indicating that heater power is not required) stored in the sensor side memory (not shown) mounted on the unit side circuit board 3073 to the main body side computer 34 as a response to the command sent from the sensor setting information reading unit 3416 of the main body side computer 34. As a result, the sensor setting information reading unit 3416 of the main body side computer 34 can acquire the setting information of the gas sensor 3060.

[0203] The unit-side computer 3074 further includes an input demultiplexing processing unit 7402 and an output multiplexing processing unit 7404. The input demultiplexing processing unit 7402 distributes the multiplexed sequence commands sent from the input multiplexing processing unit 3420 of the body-side computer 34. This is suitable when the sensor unit 3080 has a plurality of gas sensors built therein.

[0204] When the sensor unit 3080 has a plurality of built-in gas sensors, the output multiplexing processing unit 7404 multiplexes the standardized measurement results received from the plurality of gas sensors and outputs them as a sequence, and transmits them to the main body side computer 34. With these structures, the main body side computer 34 can control the gas detection module 3050 at the same time when the plurality of gas sensors are installed.

[0205] Comparing the unit-side computer 3074 of the third embodiment with the base-side computer 74 and the sensor-side computer 64 of the first embodiment, it can be seen that the unit-side computer 3074 integrally has the functions of both the base-side computer 74 and the sensor-side computer 64 of the first embodiment. That is, the unit-side computer 3074 is a concept that includes the base-side computer 74 and the sensor-side computer 64.

[0206] (Flow from main power on to start of measurement) The flow from turning on the main power supply to starting the measurement in the third embodiment is similar to that in the first embodiment. Fig.15 The steps described in the flowchart are the same, so the description here is omitted.

[0207] As described above, the gas detector 1 of the first embodiment and the gas detector 2001 of the second embodiment include: a common main body 10; a chamber 52, 2052 configured to be freely separable (detachable) relative to the main body 10; a gas sensor 60, 2060A, 2060B configured to be freely separable (detachable) relative to the chamber; and a sensor base 70, 2070 configured to be freely separable (detachable) relative to the gas sensor and the main body.

[0208] In this way, the best gas sensor can be freely selected from various gas sensors for use according to the purpose of use. In addition, when the gas sensor or the sensor base fails, only the gas sensor or the sensor base needs to be replaced, so the maintenance burden can be reduced.

[0209] In the gas detector 1 of the first embodiment and the gas detector 2001 of the second embodiment, the chamber 52, 2052 has a sensor insertion port 58, 2058A, 2058B for inserting the gas sensor 60, 2060A, 2060B. In addition, the gas sensor 60, 2060A, 2060B has an annular sensor side sealing surface 68, 2068A, 2068B that can abut against the sensor insertion port. As a result, the sensor insertion port 58, 2058A, 2058B can abut against the sensor side sealing surface 68, 2068A, 2068B and the internal space 54, 2054A, 2054B can be made into a closed space simply by swinging the chamber 52, 2052 and fixing it to the sensor base 70, 2070.

[0210] At this time, the chamber 52, 2052 has the chamber side engaging portion 55, 2055, and the sensor base 70, 2070 has the base side engaging portion 79, 2079 engaged with the chamber side engaging portion 55, 2055, so that the chamber 52, 2052 can be easily fixed to the sensor base 70, 2070. On the other hand, if the mutual engaging state is released, the chamber 52, 2052 can be relatively moved (relatively swung) with respect to the sensor base 70, 2070, so that the gas sensor 60, 2060A, 2060B can be easily replaced.

[0211] In particular, in the case of the gas detection module 2050 exemplified in the gas detector 2001 of the second embodiment, since a plurality of gas sensors 2060A and 2060B can be mounted on the sensor base 2070, a plurality of target gases can be detected simultaneously, or the same target gas can be detected by different methods. In the base-side computer 2074, the multiplexed sequence command sent from the main body-side computer 34 can be distributed to the plurality of gas sensors 2060A and 2060B through the input demultiplexing processing unit 7402. At the same time, in the base-side computer 2074, the standardized measurement results received from the plurality of gas sensors 2060A and 2060B can be multiplexed and converted into a sequence output and transmitted to the main body-side computer 34 through the output multiplexing processing unit 7404. With these structures, the main body-side computer 34 can simultaneously control the plurality of gas sensors 2060A and 2060B built in the gas detection module 2050.

[0212] As shown in the gas detectors 1, 2001, and 3001 of the first to third embodiments, the sensor side interfaces of the gas detection module 50 of the first embodiment, the gas detection module 2050 of the second embodiment, and the gas detection module 3050 of the third embodiment are completely consistent with each other. Thus, the three gas detection modules 50, 2050, and 3050 can be freely replaced for the common main body 10.

[0213] For example, there may be a gas detection method in which the gas sensors 60, 2060A, 2060B are compact and can allow a single gas sensor to operate, as in the gas detection module 50 of the first embodiment and the gas detection module 2050 of the second embodiment, and a gas detection method in which the gas sensor 3060 is integrally built into the sensor unit 3080 and direct operation of a single gas sensor should not be allowed, as in the gas detection module 3050 of the third embodiment.

[0214] In this way, when the specifications of the gas sensor side are diversified, it is difficult to make the interface of the gas sensor 60 of the first embodiment, the interface of the two gas sensors 2060A and 2060B of the second embodiment, and the interface of the sensor unit 3080 of the third embodiment consistent with each other. Therefore, in the first embodiment to the third embodiment, the connection interface on the main body 10 side of all the chambers 52, 2052, and 3052 is made completely consistent. That is, by interposing the chambers 52, 2052, and 3052 between various gas sensors and the main body 10, the function of an adapter that ensures connection interchangeability is exerted. As a result, the main body 10 can be shared among the three gas detection modules 50, 2050, and 3050.

[0215] For the gas detector 1 of the first embodiment and the gas detector 2001 of the second embodiment, the main body side computer 34, the base side computers 74, 2074, and the sensor side computers 64, 2064A, and 2064B are connected in series with each other. In this way, by connecting three computers, in the main body side computer 34, instructions can be multiplexed and sent, and in the base side computers 74, 2074, the multiplexed instructions can be distributed to each gas sensor. Similarly, in the base side computers 74, 2074, the measurement results (outputs) of each gas sensor can be multiplexed and sent, and in the main body side computer 34, the measurement results of each gas sensor are displayed separately on the display device by separating the multiplexed outputs. In addition, by multiplexing instructions and signals, the number of pins of the main body side connector 26A can be reduced.

[0216] Furthermore, in the sensor-side computers 64 , 2064A, and 2064B, the measurement results (outputs) of the gas sensors can be standardized (commonly protocolized), thereby simplifying signal processing in the main body-side computer 34 and the base-side computer 74 , and 2074 .

[0217] The gas detector 1 of the first embodiment and the gas detector 2001 of the second embodiment are provided with a heater power supply unit 210 as an additional function supply unit on the main body 10 side. The supply voltage of the heater power supply unit 210 is controlled by the main body side computer 34. That is, the main body side computer 34 functions as an additional function control unit that controls the additional function supply unit. As a result, it is not necessary to build a heater power supply and a voltage control function that are easy to become large inside the gas detection module 50, 2050, so that the gas detection module 50, 2050 and the gas sensor 60, 2060A, 2060B mounted on the gas detection module 50, 2050 can be made compact. As a result, in the gas detection module 50, 2050, only the gas sensor 60, 2060A, 2060B can be replaced. It should be noted that in the first and second embodiments, the case of supplying additional power such as heater power is exemplified as an additional function, but the present invention is not limited to this. For example, a high-frequency signal, an optical signal, etc. can also be supplied as an additional signal (additional function) according to the purpose of the gas sensor.

[0218] It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

Claims

1. A gas detector, characterized in that: Detect gas and have: a main body having a main body side inflow path for the gas to flow in, and a main body side outflow path for the gas to flow out; a first gas detection module, which is disposed in a state of being detachable from the main body and detects the gas; and a second gas detection module, which is configured to be detachable from the main body and detects the gas; The first gas detection module has: a first chamber disposed in a state detachable from the main body and having a first chamber-side inflow passage detachably connected to the main body-side inflow passage, a first chamber-side outflow passage detachably connected to the main body-side outflow passage, and a first internal space between the first chamber-side inflow passage and the first chamber-side outflow passage; a first gas sensor disposed in a state of being separable from the first chamber, wherein a gas detection portion of the first gas sensor contacts the gas passing through the first internal space; and a first sensor base, which is arranged in a state of being detachable from the first gas sensor and has a first sensor receiving connector connected to a first sensor-side connector of the first gas sensor in a detachable manner, and a first main body receiving connector connected to a main body-side connector of the main body in a detachable manner, thereby electrically connecting the gas sensor and the main body, The second gas detection module has: a second chamber disposed in a state detachable from the main body and having a second chamber-side inflow passage detachably connected to the main body-side inflow passage, a second chamber-side outflow passage detachably connected to the main body-side outflow passage, and a second internal space between the second chamber-side inflow passage and the second chamber-side outflow passage; and a second sensor unit disposed in a state of being separable from the second chamber, The second sensor unit of the second gas detection module further comprises: a second shell; a second gas sensor disposed inside the second housing and in contact with the gas passing through the second internal space; as well as The second main body receiving connector is arranged on the second housing and is connected to the main body side connector of the main body in a detachable manner. The connection layout of the first chamber side inflow path, the first chamber side outflow path and the first main body receiving connector relative to the main body in the first gas detection module is the same as the connection layout of the second chamber side inflow path, the second chamber side outflow path and the second main body receiving connector relative to the main body in the second gas detection module.

2. The gas detector according to claim 1, characterized in that The shape of the connection interface between the first chamber in the first gas detection module and the first gas sensor is different from the shape of the connection interface between the second chamber in the second gas detection module and the second sensor unit.

3. The gas detector according to claim 1, characterized in that The first chamber has a first chamber side engaging portion, The first sensor base has a first base-side engaging portion engaged with the first chamber-side engaging portion. The first chamber is fixed to the first sensor base by engaging the first chamber-side engaging portion with the first base-side engaging portion. The second chamber has a second chamber side engaging portion, The main body has a second main body side engaging portion engaged with the second chamber side engaging portion, The second chamber is fixed to the body by engaging the second chamber-side engaging portion with the second body-side engaging portion.

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