Insertion-type gas measuring device

Abstract

To provide an insertable gas measuring device that allows for easy replacement of the gas sensor while the gas measuring device remains installed. [Solution] An insertable gas measuring device 10 comprises a device body 70 and a cylindrical measuring probe 11 configured to be insertable into a detection target space S. The measuring probe 11 is configured such that a gas detection unit 30 equipped with a gas sensor 50 is placed inside a sheath 12 to which the device body 70 is fixed at the base end, and the gas detection unit 30 is provided so as to be insertable into and removeable from the sheath 12.

Description

Technical Field

[0001] The present invention relates to an insertion-type gas measurement device used, for example, for measuring the concentration of organic solvent gas, flammable gas or inflammable gas in a drying furnace.

Background Art

[0002] For example, in a drying furnace used for manufacturing lithium-ion batteries that are suitably used in mobile devices such as mobile phones and PCs, gas of NMP (N-methyl-2-pyrrolidone) solvent (hereinafter referred to as "solvent gas") exists. For example, depending on the concentration of the solvent gas, there is a risk of explosion, so it is necessary to monitor the solvent gas in the drying furnace.

[0003] As a gas measurement device for measuring gas concentration in a furnace, there has been proposed one that includes, for example, a long cylindrical measurement probe having a gas detection part at the tip end, and a device main body provided at the base end of the measurement probe, wherein the tip end portion of the measurement probe is inserted into the drying furnace through the furnace wall, and is configured to be fixable to the furnace wall in a state where the gas detection part is positioned in a predetermined region inside the drying furnace (see Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problem to be Solved by the Invention

[0005] In such a gas measurement device as described above, the gas sensor is used under severe conditions such as high temperature conditions, high humidity conditions, or conversely dry conditions, so it is necessary to replace the gas sensor periodically. However, when replacing the gas sensor, there was a problem in terms of work efficiency, as it was necessary to stop the exhaust fan for ventilation inside the furnace and then temporarily remove the gas measuring device.

[0006] This invention was completed in view of these circumstances, and aims to provide an insertable gas measuring device that allows for easy replacement of the gas sensor while the gas measuring device remains installed. [Means for solving the problem]

[0007] The present invention provides an insertable gas measuring device comprising a device body and a cylindrical measuring probe configured to be insertable into a space to be detected. The measuring probe comprises a sheath configured to be fixed to a partition wall that divides the space to be detected, with the device body fixed to the proximal end portion of the sheath, and a gas detection unit electrically connected to the device body and positioned inside the sheath. The gas detection unit comprises a support frame configured so that its proximal end portion extends outward from the proximal end of the sheath, a sensor holder provided at the tip of the support frame, and a gas sensor detachably mounted on the sensor holder, and is configured to be insertable and detachable from the sheath, thereby solving the above-mentioned problems. [Effects of the Invention]

[0008] According to the invention of claim 1, since the gas detection unit is configured to be insertable and removable from the outer tube, when replacing the gas sensor, only the gas detection unit needs to be pulled out from the outer tube while the insertable gas measuring device remains installed, thus making it easy to replace the gas sensor.

[0009] According to the invention of claim 2, it is possible to avoid variations in the orientation of the gas sensor when inserting or removing the gas detection unit, and to obtain a stable reading value. According to the invention of claim 3, the connection terminal of the replacement gas sensor has a female contact socket, which suppresses the deterioration of the male contact pins that are contacts in the sensor holder, and enables stable electrical connection even when the gas sensor is replaced. [Brief explanation of the drawing]

[0010] [Figure 1] This is a longitudinal cross-sectional view showing the configuration of an insertion-type gas measuring device according to one embodiment of the present invention. [Figure 2] This diagram schematically shows the structure of the tip portion of the measuring probe. [Figure 3] This is a cross-sectional perspective view showing the configuration of the connecting member. [Figure 4] This is an exploded perspective view that schematically shows the structure of the proximal end portion of the measuring probe. [Figure 5] This is a perspective view showing the configuration of the gas detection unit. [Figure 6] This is a cross-sectional view along the length of the gas detection unit, showing its configuration. [Figure 7] This is a perspective view showing the configuration of the connector components. [Figure 8] This is a cross-sectional perspective view illustrating the configuration of the gas sensor. [Figure 9] This is a cross-sectional view taken from the tip end in the longitudinal direction, when the tip portion of the measuring probe is cut by a plane perpendicular to the central axis of the outer tube. [Figure 10] This is a cross-sectional view along line AA in Figure 6. [Figure 11] This is a side view showing the configuration of the operating components. [Figure 12] This is a schematic perspective view showing the structure of the proximal end portion of an insertion-type gas measuring device. [Figure 13] This is a perspective view of the device body, taken from the base end in the longitudinal direction. [Figure 14] This is a partially fractured cross-sectional view, taken from the longitudinal end, schematically illustrating the fixing structure of the main body of the device. [Figure 15]It is a perspective view showing a state where the gas detection unit is pulled out from the outer casing. [Figure 16] It is a schematic diagram for explaining a mode switching operation of moving the gas detection unit from a measurement position to a calibration position. [Figure 17] It is a cross-sectional view along the length direction showing the configuration of the distal end portion of the measurement probe when the gas detection unit is positioned at the calibration position. [Figure 18] It is a cross-sectional view as viewed from the distal end side in the length direction when the distal end portion of the measurement probe is cut along a plane orthogonal to the central axis of the outer tube when the gas detection unit is positioned at the calibration position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] As shown in FIG. 1, an insertion-type gas measurement apparatus 10 according to the present embodiment includes an elongated measurement probe 11, and an apparatus main body 70 provided on the proximal end side in the length direction of the measurement probe 11.

[0012] The measurement probe 11 includes a cylindrical outer tube 12 with a closed distal end, a connecting member 20 attached to a proximal end portion of the outer tube 12 in the length direction for integrally connecting the apparatus main body 70 to the measurement probe 11, and a gas detection unit 30 that is arranged to extend in the length direction along the outer tube 12 inside the outer tube 12 and is electrically connected to the apparatus main body 70 via a signal transmission cable 80.

[0013] The outer tube 12 is constituted by, for example, a straight tubular member 13 made of stainless steel, and a cap member 15 provided at the distal end of the straight tubular member 13 and having a gas introduction opening formed on a peripheral surface thereof. The outer tube 12 may be configured such that the straight tubular member 13 and the cap member 15 are integrated.

[0014] The outer tube 12 has a flange 14 located at a predetermined distance from the tip towards the base end, and is configured to be fixable to a partition wall 90 that divides the detection target space S, so that the tip portion of the measuring probe 11 can be inserted into the detection target space S. The flange 14 may be fixed to the outer surface of the outer tube 12 by, for example, welding, or it may be provided so that its position in the longitudinal direction of the outer tube 12 can be adjusted. In this embodiment, the partition wall 90 has a tubular mounting portion 91 that extends in a direction perpendicular to the flow direction of the gas to be tested within the detection target space S (indicated by the white arrow in Figure 1), and the flange 14 of the measuring probe 11 is fixed to a mounting flange portion 92 provided at the tip of the mounting portion 91 by a fixing screw 95.

[0015] The flange 14 is positioned such that, for example, the measuring probe 11 can be inserted at least 250 mm into the detection target space S, and the device body 70 can be fixed at a position at least 90 mm away from the flange 14 towards the base end. This makes it possible to accurately measure the gas of the test gas, and by ensuring a distance between the flange 14 and the device body 70, thermal influence on the device body 70 (influence of radiant heat from the partition wall 90) can be eliminated.

[0016] As shown in Figure 2, the cap member 15 has a large-diameter cylindrical portion 16a and a small-diameter cylindrical portion 16b with a bottom that is continuous with the tip of the large-diameter cylindrical portion 16a. A gas introduction opening 17 is formed in the large-diameter cylindrical portion 16a. The gas introduction opening 17 includes a plurality of slit-shaped gas flow holes 18a that are arranged at predetermined intervals in the circumferential direction and extend in the longitudinal direction, and a plurality of through holes 18b that are formed at the base end of the gas flow holes 18a in the longitudinal direction and have a substantially elliptical opening shape. The through holes 18b are formed at predetermined intervals so as to be located between adjacent gas flow holes 18a in the circumferential direction.

[0017] The connecting member 20 is made of, for example, aluminum die-cast (ADC12), and as shown in Figure 3, has a trough-shaped portion 21a that holds the lower surface portion of the outer tube 12, and a cylindrical portion 21c that extends toward the base end, continuous with the trough-shaped portion 21a. Plate-shaped portions 21b extending radially are provided at each of the circumferential ends of the trough-shaped portion 21a.

[0018] A fixing portion 22 for fixing the device body 70 is provided on the outer circumferential surface at the tip of the cylindrical portion 21c. In this embodiment, as shown in Figure 4, the fixing portion 22 is composed of three main body mounting screw fastening portions provided at equal intervals in the circumferential direction. The main body mounting screw fastening portions may be provided in three or more positions, as long as they enable stable fixing of the device body 70 and create a structure that makes it difficult for heat from the outer tube 12 to be transferred to the device body 70.

[0019] Furthermore, the cylindrical portion 21c is provided with a flap-shaped position regulating portion 23 that restricts the circumferential position of the gas detection unit 30 relative to the outer tube 12, extending longitudinally outward from the base end of the cylindrical portion 21c.

[0020] The connecting member 20 is fitted onto the base end of the outer tube 12 with its cylindrical portion 21c protruding outward from the base end of the outer tube 12. Mounting brackets 25 are screwed to each plate-shaped portion 21b, and fixing screws 26 are attached from the outer surface of the trough-shaped portion 21a to hold the outer tube 12 in place. This reduces the contact area of ​​the connecting member 20 with the outer tube 12, thereby suppressing the thermal influence on the device body 70 due to heat conduction through the outer tube 12.

[0021] As shown in Figure 5, the gas detection unit 30 includes a support frame 31, a gas detection unit 35 located at the tip of the support frame 31, an operating member 60 attached to the base of the support frame 31, and a calibration gas supply pipe 32 and a gas discharge pipe 33 for supplying calibration gas.

[0022] The support frame 31 is made of, for example, stainless steel (SUS304), and is formed so that its cross-sectional shape perpendicular to the longitudinal direction is U-shaped. The support frame 31 extends outward from the base end of the outer tube 12 when positioned inside the outer tube 12.

[0023] As shown in Figure 6, the gas detection unit 35 includes a sensor holder 36, a gas sensor 50 detachably mounted on the sensor holder 36, and a protective member 45 provided to cover the periphery of the gas sensor 50.

[0024] The sensor holder 36 is made of, for example, stainless steel casting (SCS13) and has a cylindrical gas sensor mounting portion 37 and a rectangular tubular fixing portion 38 that is continuous with the base end of the gas sensor mounting portion 37. The gas sensor mounting portion 37 has a small diameter cylindrical portion 37a and a large diameter cylindrical portion 37b that is continuous with the base end of the small diameter cylindrical portion 37a via a stepped portion. An O-ring 39 is fitted to the stepped portion, which allows the inside of the outer tube 12 to be airtightly sealed. The base end of the large-diameter cylindrical portion 37b has an annular end wall portion 37c that protrudes radially inward along the entire circumference, and a connector member 40 is arranged on the end wall portion 37c.

[0025] As shown in Figure 7, the connector member 40 is made of a heat-resistant insulating material and has a main body 41 having a pin hole 42 that opens toward the tip, and a male contact pin 43 that is placed inside the pin hole 42 and electrically connected to the lead portion of the gas sensor 50.

[0026] The gas sensor 50 is, for example, a catalytic combustion type gas sensor, and as shown in Figure 8, comprises a gas detection element support base plate 51 and a compensation element support base plate 56 arranged opposite to each other at positions spaced apart in the axial direction, a pair of detection element lead portions 52 provided to extend axially through the gas detection element support base plate 51 and the compensation element support base plate 56, a pair of compensation element lead portions 57 provided to extend axially through the compensation element support base plate 56, a gas detection element 53 electrically connected to the detection element lead portions 52, and a compensation element 58 electrically connected to the compensation element lead portions 57. The gas detection element 53 is constructed by forming a sensitive portion containing an oxidation catalyst on the surface of a resistor that generates heat when an electric current is applied. The compensation element 58 is constructed by forming an insensitive portion that is inert to the gas to be detected on the surface of a resistor that generates heat when an electric current is applied. The lead portion 52 for the detection element has a conductive pin 52a extending axially to which the gas detection element 53 is connected at its tip, and a female contact socket 52b provided at the base end of the conductive pin 52a. The lead portion 57 for the compensation element has a conductive pin 57a ​​extending axially to which the compensation element 58 is connected at its tip, and a female contact socket 57b provided at the base end of the conductive pin 57a. In Figure 8, 59 is, for example, a flame arrester made of a sintered metal body.

[0027] The gas sensor 50 is attached to the connector member 40 by inserting the male contact pins 43 of the sensor holder 36 into the female contact sockets 52b and 57b. The replacement gas sensor 50 has female contact sockets 52b and 57b for the detection element lead portion 52 and the compensation element lead portion 57, which suppresses deterioration of the male contact pins 43, which are contacts in the connector member 40, and ensures a stable electrical connection even when the gas sensor 50 is replaced.

[0028] When the gas sensor 50 is attached to the connector member 40, as shown in Figure 9, the gas detection element 53 and the compensation element 58 are positioned so that they are not located below the detection element lead portion 52 and the compensation element lead portion 57 with respect to the flow direction of the gas to be tested (indicated by the white arrows in Figure 9). In this embodiment, the gas sensor 50 is positioned such that a plane N1 including a pair of lead portions 52 for detection elements and a plane N2 including a pair of lead portions 57 for compensation elements are orthogonal to each other, and planes N1 and N2 are tilted at a 45° angle with respect to the flow direction of the gas being tested. By positioning the gas sensor 50 in this manner, when the measuring probe 11 is positioned so as to extend horizontally with respect to the detection target space S through which the gas under test flows vertically, it becomes more difficult for heat to dissipate from the gas detection element 53 and the compensation element 58. This reduces the impact on the sensitivity of the gas sensor 50 caused by the heat from the gas detection element 53 and the compensation element 58 being dissipated through the detection element lead portion 52 and the compensation element lead portion 57, thus enabling more reliable and stable readings.

[0029] As shown in Figure 6, the protective member 45 is configured to have a multi-stage cylindrical shape and has a large-diameter cylindrical portion 46a that fits onto the small-diameter cylindrical portion 37a of the sensor holder 36, and a small-diameter cylindrical portion 46b that has gas flow holes 47 on its circumferential surface and is continuous with the tip of the large-diameter cylindrical portion 46a. The small-diameter cylindrical portion 46b has an outer diameter smaller than the inner diameter of the small-diameter cylindrical portion 16b of the cap member 15, and can be inserted into the small-diameter cylindrical portion 16b of the cap member 15.

[0030] In this insertable gas measuring device 10, as shown in Figure 10, a gas introduction space Ra is formed between the inner circumferential surface of the cap member 15 and the outer circumferential surface of the protective member 45, and the gas flow holes 47 in the protective member 45 and the gas flow holes 18a in the cap member 15 are positioned so as not to overlap each other in the circumferential direction. As a result, the gas flow path leading to the gas sensor 50 has a labyrinth structure.

[0031] As shown in Figure 11, the operating member 60 has a cylindrical portion 61a that is rotatably and slidably fitted inside the cylindrical portion 21c of the connecting member 20, and a substantially cylindrical knob portion 61b with a larger diameter than the cylindrical portion 61a that is continuous with the base end of the cylindrical portion 61a. The operating member 60 is fixed to the connecting member 20 by a fixing screw 63 (Figure 4).

[0032] A cam groove 62 is formed on the outer circumferential surface of the cylindrical portion 61a, to which a follower 27 (see Figure 4) attached to the connecting member 20 is coupled. The cam groove 62 has a first straight portion 62a formed to extend circumferentially at the longitudinal end, an inclined portion 62b formed to extend inclined toward the longitudinal base end and continuous with the first straight portion 62a, and a second straight portion 62c formed to extend circumferentially at the longitudinal base end and continuous with the inclined portion 62b.

[0033] As shown in Figure 12, the knob portion 61b has contact portions 64 formed on both sides of the rotational axis, which are created by cutting out a part of the circumferential surface so that it can contact the position regulating portion 23 of the connecting member 20. This configuration makes it possible to avoid variations in the orientation of the gas sensor 50 when the gas detection unit 30 is positioned at the measurement position or calibration position.

[0034] As shown in Figure 5, the calibration gas supply pipe 32 and the gas discharge pipe 33 are supported by the support frame 31 and are arranged to extend in the longitudinal direction. The base end of the calibration gas supply pipe 32 and the base end of the gas discharge pipe 33 are connected to the calibration gas supply port 65 and gas discharge port 66 (see Figure 12) provided on the operating member 60. Furthermore, the tip of the calibration gas supply pipe 32 and the tip of the gas discharge pipe 33 are located within the gas sensor placement space Rb surrounded by the protective member 45, as shown in Figure 9.

[0035] As shown in Figure 13, the main body of the device 70 includes a pressure-resistant explosion-proof container 71 made of, for example, cast iron, and various electronic components are arranged inside this pressure-resistant explosion-proof container 71. The pressure-resistant explosion-proof container 71 has cable entry ports 72a and 72b for drawing in a signal transmission cable 80 and a power supply cable, and cable glands 73a and 73b are attached to each of the cable entry ports 72a and 72b in a way that allows them to be attached and detached by screwing.

[0036] In the above-described insertable gas measuring device 10, the pressure-resistant explosion-proof container 71 has an annular mounting portion 75 through which the cylindrical portion 21c of the connecting member 20 can be inserted. As shown in Figure 14, the device body 70 is fixed to the connecting member 20 such that an air layer G is formed between it and the circumferential surface of the connecting member 20, thereby preventing direct thermal contact with the outer tube 12. The air layer G is formed by a gap that extends around the entire circumference between the inner circumferential surface of the mounting portion 75 and the outer circumferential surface of the connecting member 20. The device body 70 is fixed by screwing the mounting portion 75 to the fixing portion 22 with fixing screws 76. The width of the gap is, for example, 0.2 to 10 mm. As described above, in this embodiment, the device body 70 is fixed only to the three fixing parts 22 of the connecting member 20, which reduces the thermal impact on the device body 70 due to heat conduction through the outer tube 12, even when used in an environment where the temperature of the detection target space S is high. By adopting such a fixing structure for the device body 70 to the outer tube 12, it is possible to reliably prevent failure or damage to the electronic components arranged inside the device body 70.

[0037] However, the above-mentioned insertable gas measuring device 10 is heavy because the main body 70 is made of, for example, cast iron, and the outer tube 12 is long in itself. Therefore, if the entire insertable gas measuring device 10 is to be removed when replacing the gas sensor 50, replacing the gas sensor 50 will be a considerable amount of work. However, in the above-described insertable gas measuring device 10, by removing the fixing screws 63 and the drive element 27, as shown in Figure 15, it is possible to pull out only the gas detection unit 30 from the outer casing 12 while the outer casing 12 and the device body 70 remain attached to the partition wall 90, thereby making it possible to easily replace the gas sensor 50. After replacing the gas sensor 50, when the gas detection unit 30 is inserted into the outer tube 12, the position regulating unit 23 can regulate the circumferential position of the gas detection unit 30 relative to the outer tube 12, thereby preventing variations in the orientation of the gas sensor 50.

[0038] In insertion-type gas measuring devices, it is necessary to periodically calibrate the gas sensor in order to achieve high-precision and accurate detection. In this insertable gas measuring device 10, when calibrating the gas sensor 50, the calibration gas can be supplied to the gas sensor 50 without being affected by external disturbances by simply rotating the gas detection unit 30, and the gas sensor 50 can be calibrated while the insertable gas measuring device 10 remains installed. Specifically, as shown in Figure 16, after removing the fixing screw 63, the driver 27 is moved relative to the cam groove 62 by rotating the knob 61b on the operating member 60. The gas detection unit 30 is moved toward the longitudinal end of the outer tube 12 by the action of the cam groove 62 so that it is positioned from the measurement position to the calibration position. As a result, as shown in Figure 17, the small diameter cylindrical portion 46b of the protective member 45 is inserted into the small diameter cylindrical portion 16b of the cap member 15, and the gas flow hole 47 of the protective member 45 is closed by the small diameter cylindrical portion 16b of the cap member 15. This restricts the introduction of the gas under test into the gas sensor placement space Rb, so that calibration can be performed without being affected by disturbances by supplying the calibration gas from the calibration gas supply port 65.

[0039] In this case, as shown in Figure 18, the gas sensor 50 is positioned such that the gas detection element 53 and the compensation element 58 are not located below the detection element lead portion 52 and the compensation element lead portion 57 with respect to the flow direction of the gas to be tested (indicated by the white arrow in Figure 17), so as to the plane extending in the flow direction of the gas to be tested and in the longitudinal direction of the measurement probe 11, the gas detection unit 30 is positioned at the measurement position. In this manner, instead of simply sliding the gas detection unit 30 along its length, the gas detection unit 30 is rotated to move along its length. This structure allows the rotation range of the gas detection unit 30 to be restricted by the position restricting portion 23 and cam groove 62 of the connecting member 20. Furthermore, because position adjustment is possible with a small rotation angle, variations in the orientation of the gas sensor 50 due to the movement of the gas detection unit 30 can be avoided, and a stable reading can be obtained. As a result, the gas sensor 50 can be calibrated under conditions substantially the same as when the gas detection unit 30 is positioned at the measurement location, thus enabling high reliability of the reading.

[0040] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications can be made. For example, in the above embodiment, a gas sensor configured to have a compensation element was described, but the gas sensor may not have a compensation element. Even in such a configuration, it is sufficient that the gas detection element is positioned so that it is not located below the lead portion with respect to the flow direction of the gas when the measuring probe is positioned in a orientation that extends horizontally to the detection target space in which the gas to be tested flows vertically. [Explanation of symbols]

[0041] 10. Insertion-type gas measuring device 11. Measuring probe 12 ... mantle tube 13 ··· Straight tubular member 14 ··· Flange 15 ··· Cap component 16a ··· Large diameter cylindrical section 16b ··· Small diameter cylindrical part 17. Gas inlet opening 18a ··· Gas flow hole 18b... Through hole 20 ··· Connecting component 21a...Gutter-like part 21b ··· Plate-like portion 21c... Cylindrical part 22...Fixed part 23 ... Position regulation part 25 ··· Mounting bracket 26 ··· Fixing screws 27 ··· Subordinate verb 30... Gas detection unit 31 ··· Support frame 32 ··· Calibration gas supply pipe 33... Gas exhaust pipe 35... Gas detection unit 36... Sensor holder 37. Gas sensor mounting section 37a ··· Small diameter cylindrical part 37b ··· Large diameter cylindrical section 37c... End wall part 38...Fixed part 39 ··· O-ring 40... Connector components 41 ··· Main body 42... Pinholes 43... Male contact pin 45 ··· Protective material 46a ··· Large diameter cylindrical section 46b ··· Small diameter cylindrical part 47... Gas flow holes 50... Gas sensor 51 ··· Base plate for supporting gas detection element 52 ··· Lead section for detection element 52a... Conductive pin 52b ··· Female contact socket 53... Gas detection element 56 ··· Base plate for supporting compensation element 57 ··· Lead section for compensation element 57a ··· Conductive pin 57b ··· Female contact socket 58... Compensation element 59 ··· Frame arrester 60 ··· Operating components 61a ··· Cylindrical part 61b ··· Knob part 62... Cam groove 62a ··· First straight section 62b... Inclined part 62c... 2nd straight section 63 ··· Fixing screws 64 ··· Contact part 65 ··· Calibration gas supply port 66... ​​Gas outlet 70 ··· Main unit of the device 71... Pressure-resistant explosion-proof container 72a ... Cable entry point 72b ··· Cable entry point 73a ··· Cable gland 73b ··· Cable gland 75 ··· Mounting part 76 ··· Fixing screws 80 ··· Signal transmission cable 90 ... bulkhead 91 ··· Mounting part 92 ··· Mounting flange section 95 ··· Fixing screws G ··· Air layer Ra ··· Gas introduction space Rb ··· Gas sensor placement space S ··· Detection target space

Claims

1. An insertable gas measuring device comprising a main body and a cylindrical measuring probe configured to be inserted into the space to be detected, The measuring probe comprises a casing configured to be fixed to a partition wall that divides the space to be detected, with the main body of the device fixed to its base end, and a gas detection unit electrically connected to the main body of the device and located inside the casing. The gas detection unit is an insertable gas measuring device characterized by comprising a support frame configured such that its base end portion extends outward from the base end of the outer tube, a sensor holder provided at the tip of the support frame, and a gas sensor detachably mounted on the sensor holder, and being provided so as to be insertable and detachable from the outer tube.

2. An operating member is provided on the base end portion of the support frame. The insertable gas measuring device according to claim 1, characterized in that the operating member has a position regulating portion that regulates the circumferential position of the gas detection unit with respect to the outer tube.

3. The gas sensor comprises a gas detection element having a sensing portion containing an oxidation catalyst formed on the surface of a resistor that generates heat when an electric current is applied, and a pair of lead portions electrically connected to each end of the resistor. The lead portion has a conductive pin extending in the longitudinal direction to which the resistor of the gas detection element is connected at the tip, and a female contact socket provided at the base end of the conductive pin. The insertion-type gas measuring device according to claim 1, characterized in that the sensor holder has a male contact pin that is fitted into the female contact socket of the gas sensor.

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