Gas detector

Abstract

To provide a gas detector having a plurality of flow passages branching from one common gas introduction port, the gas detector being capable of correcting gas of a sensor for each flow passage.SOLUTION: A gas detector 1 includes: a plurality of flow passages with at least one sensor formed in between; a branch flow passage 53 connected to one gas introduction port 12 at one end and branching into at least two passages on the other side; a gas flow passage into which a correction gas flows; and a flow passage formation unit in which a branch flow passage and a correction gas flow passage are formed. The flow passage formation unit can switch the state of connecting the plurality of flow passages and the branch flow passage together and the state of connecting the correction gas flow passage and one of the plurality of flow passages.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Some gas detectors have multiple types of sensors in order to detect multiple types of gases with one gas detector. As such a gas detector, there is known a detector having multiple intake lines (flow paths) provided in a measurement chamber, each line being provided with a gas sensor and a flow rate control valve (see, for example, Patent Document 1). There is also known a gas detector in which each flow path does not have an individual gas inlet, but has multiple flow paths branched from a common gas inlet, and each of the multiple flow paths has a sensor (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-3142109 [Patent Document 2] Japanese Patent Application Publication No. 4-12608 Summary of the Invention [Problem to be solved by the invention]

[0004] In gas detectors, in order to perform highly accurate and precise detection, gas calibration of each sensor is performed periodically. In the gas detector described in Patent Document 1, when performing gas calibration of each sensor, each flow path in which a sensor is provided has an individual gas inlet, so that gas calibration for each sensor can be performed by flowing in a calibration gas for each sensor from the gas inlet of each flow path. However, in the case of a gas detector in which each flow path does not have an individual gas inlet but has multiple flow paths branched from one common gas inlet, and each of the multiple flow paths has a sensor, if a calibration gas is introduced from one common gas inlet, the same calibration gas will reach the multiple flow paths. As a result, the same calibration gas will come into contact with the sensors of all the flow paths of each sensor, which is undesirable.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas detector which allows gas calibration of the sensor for each flow path, even in a gas detector having a plurality of flow paths branched off from a single common gas inlet. [Means for solving the problem]

[0006] The gas detector of the present invention is a gas detection device comprising a plurality of flow paths in which one or more sensors are interposed, a branch flow path connected at one end to one gas inlet and branching into two or more at the other end, a calibration gas flow path into which a calibration gas flows, and a flow path forming section in which the branch flow path and the calibration gas flow path are formed, wherein the flow path forming section is configured so as to be switchable between a state in which the plurality of flow paths and the branch flow path are connected and a state in which the calibration gas flow path and one of the plurality of flow paths are connected, The gas detector includes a case and has the plurality of flow paths within the case, an opening of the branch flow path and an opening of the calibration gas flow path are formed on a joint surface of the flow path forming part with the case, and openings of the plurality of flow paths are formed on a joint surface of the case with the flow path forming part, and the flow path forming part is configured such that the opening positions of the flow path forming part can be changed to switch connections between the openings of the branch flow paths and the openings of the calibration gas flow path and the openings of the plurality of flow paths. This is characterized by the fact that

[0007] The gas detector of the present invention is a gas detector having a plurality of flow paths branching off from a common gas inlet, and the flow path forming portion is configured to be switchable to a state in which the calibration gas flow path is connected to one of the plurality of flow paths. Therefore, during gas calibration, the calibration gas flow path is connected to only one of the plurality of flow paths, and therefore it is possible to introduce calibration gas into only one of the flow paths.

[0008] The gas detector preferably includes a case, has the plurality of flow paths within the case, and has an opening of the branch flow path and an opening of the calibration gas flow path formed on a joint surface of the flow path forming part with the case, and has openings of the plurality of flow paths formed on a joint surface of the case with the flow path forming part, and is configured such that the connection between the opening of the plurality of flow paths and the opening of the branch flow path and the connection between an opening of any one of the plurality of flow paths and the opening of the calibration gas flow path are switched by changing the position of the opening of the flow path forming part relative to the case. In a gas detector having a plurality of flow paths branched from a common gas inlet as described above, various configurations are conceivable for introducing the calibration gas into only one flow path, but the gas detector can be easily configured by configuring the flow path forming part so that the connection between the opening of the branch flow path and the opening of the calibration gas flow path and the opening of the plurality of flow paths are switched by moving the flow path forming part.

[0009] It is preferable that one of the multiple flow paths is provided with a flow rate adjustment unit, and the other flow path is provided with another flow rate adjustment unit downstream of the branch point of the branch flow path corresponding to the other flow path. In the gas detector of the present invention, the one flow path is provided with a flow rate adjustment unit, and the other flow path is provided with another flow rate adjustment unit downstream of the branch point of the branch flow path corresponding to the other flow path, so that it is possible to detect early the occurrence of a gas leak at a connection part when switching flow paths.

[0010] It is preferable that the flow path forming portion is made of a disk-shaped disk portion, and the connection state is switched by rotating the disk portion on its center to change the position of the opening. By configuring the flow path forming portion in this manner, it is possible to easily switch the flow paths.

[0011] A calibration gas protrusion having a calibration gas inlet communicating with a calibration gas flow path is protruded from the flow path forming part, and the gas detector preferably has a cover covering at least the calibration gas protrusion, and a fitting part is formed on the inside of the cover to fit with the calibration gas protrusion when the cover is closed. By forming such a fitting part, when the opening position of the flow path forming part is changed to switch the connection of the flow path, if the calibration gas protrusion is not placed in a predetermined position by mistake, the calibration gas protrusion cannot fit with the fitting part. This makes it possible to notify a user of a malfunction by, for example, being unable to close the cover. In this way, it is possible to suppress malfunctions when switching the flow path, and to prevent gas leakage caused by the malfunction.

[0012] It is preferable that a sign portion is provided to indicate the position of the calibration gas protrusion during normal operation and during calibration operation. Since the sign portion can be visually confirmed, malfunctions when switching the flow path can be suppressed, and gas leakage caused by malfunctions can be prevented. [Brief description of the drawings]

[0013] [Figure 1] 1 is a perspective view showing an outline of a configuration of a gas detector according to the present invention; [Diagram 2] 2 is a perspective view showing the gas detector shown in FIG. 1 with a cover in an open state. FIG. [Diagram 3] 2 is an exploded perspective view of the periphery of a switching portion in the gas detector shown in FIG. 1. FIG. [Figure 4] 2 is an exploded perspective view of a switching portion in the gas detector shown in FIG. 1. FIG. [Diagram 5]2 is a schematic diagram for explaining flow paths during normal operation in the gas detector shown in FIG. 1. FIG. [Figure 6] 2 is a schematic diagram for explaining flow paths during a calibration operation in the gas detector shown in FIG. 1. FIG. [Figure 7] 2 is a schematic diagram for explaining flow paths during a calibration operation in the gas detector shown in FIG. 1. FIG. [Figure 8] 2 is a plan view of the periphery of a switching portion in the gas detector shown in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the gas detector of the present invention will be described with reference to the drawings. In this specification, the terms "first", "second", etc. are used to distinguish one component from another, and are not intended to limit the number, order, or priority of the components. In this embodiment, the same components are distinguished by adding an alphabet after the number.

[0015] 1 and 2, the gas detector 1 includes a case 10 having a substantially cubic shape. The gas detector 1 also includes a cover 20 that covers a front surface 30 of the case 10. An opening 21 is provided at the top of the cover 20, and a display unit 31 provided on the front surface 30 of the case is exposed through the opening 21. The display unit 31 displays gas detection results and various messages. Note that the arrows indicating the up, down, left, right and front-to-rear directions in FIG. 1 indicate the up, down, left, right and front-to-rear directions in this embodiment.

[0016] A gas inlet 12 and a gas outlet 13 are provided on a lower surface 11 of the case 10. A first flow path 51 (not shown in FIGS. 1 and 2) and a second flow path 52 (not shown in FIGS. 1 and 2), each of which is provided with a sensor, are formed inside the case 10, as will be described in detail later. The gas detector 1 in this embodiment is configured such that a common flow path 50 (not shown in FIGS. 1 and 2) extending from the gas inlet 12 branches into the first flow path 51 and the second flow path 52, each of which is provided with a sensor.

[0017] Additionally, cover 20 is pivotally supported by case 10 at both ends of bottom surface 11 of case 10 via rotating shaft 14. As a result, cover 20 is attached so as to be able to swing about rotating shaft 14 at the bottom end of case 10, i.e., be able to be opened and closed. When cover 20 is swung about rotating shaft 14 to the open state, front surface 30 of case 10 is exposed as shown in FIG.

[0018] A display unit 31 is provided at the top of the front surface 30. A switching unit (flow passage forming unit) 40 is attached to the center of the lower part of the front surface 30 of the case 10. The switching unit 40 is configured to be capable of switching between a state in which the first flow passage 51 and the second flow passage 52 are connected to a branch flow passage 53 (not shown in Figs. 1 and 2) and a state in which the calibration gas flow passage (calibration gas inflow passage 46 (not shown in Figs. 1 and 2)) is connected to either the first flow passage 51 or the second flow passage 52, in order to cause the calibration gas to flow into each of the first flow passage 51 and the second flow passage 52. The switching unit 40 has a disk-shaped disk portion 41 and a cylindrical portion 42 that is extended from the disk portion 41 and protrudes toward the front side.

[0019] The switching unit 40 has a knurled screw 43 in the center of the disk portion 41, and is fixed to the case 10 by the knurled screw 43. The switching unit 40 is fixed to the case 10 by this knurled screw 43. When the knurled screw 43 is loosened, the switching unit 40 can be moved a predetermined distance away from the case 10 with the knurled screw 43 inserted, and the switching unit 40 can be rotated in the left-right direction.

[0020] The switching unit 40 will be described with reference to Figures 3 and 4. The disk portion 41 of the switching unit 40 has a first disk portion 61 in which a cylindrical portion 42 is formed, and a second disk portion 62 fixed to the back surface of the first disk portion 61. Below the through hole into which the knurled screw 43 of the first disk portion 61 is inserted, a calibration gas inlet 45 opens at the tip of a calibration gas protruding portion 44 protruding toward the front side. The calibration gas inlet 45 communicates with a calibration gas inlet passage 46 that penetrates the entire first disk portion 61 and the second disk portion 62.

[0021] The mounting portion 32 to which the switching portion 40 of the front surface 30 of the case 10 is attached has a plurality of openings 33a to 33f and a screw hole 34 into which the knurled screw 43 is inserted and screwed. The plurality of openings 33a to 33f are located on a concentric circle centered on the screw hole 34, and are provided so that adjacent openings are at an angle of 60 degrees. Among the openings 33a to 33f, the opening 33c communicates with a common flow path 50 (not shown in FIGS. 3 and 4) from the gas inlet 12, and the openings 33a and 33b communicate with a first flow path 51 (not shown in FIGS. 3 and 4) and a second flow path 52 (not shown in FIGS. 3 and 4), respectively. The remaining openings 33d to 33f do not communicate with any of the flow paths.

[0022] On the back side of the second disk portion 62, protrusions 35a to 35f are formed corresponding to these openings 33a to 33f. Although details will be described later, in normal times, each of the protrusions 35a to 35f is inserted into the corresponding opening 33a to 33f. The switching portion 40 has a branch flow path 53, and the branch flow path 53 includes a branch flow path inlet 54 that opens at the tip of the protrusion 35c, and two branch flow path outlets 55a, 55b that open at the tips of the protrusions 35a and 35b. That is, in this embodiment, the switching portion 40 is formed with a branch flow path 53 that is connected at one side to the opening 33c via the protrusion 35c and is connected at the other side to the openings 33a, 33b via the protrusions 35a, 35b. The branch flow path 53 in this embodiment means a flow path from the branch flow path inlet 54 to the two branch flow path outlets 55a, 55b. The branch flow path inlet 54 and the two branch flow path outlets 55a, 55b are all present on a concentric circle centered on the screw hole 47 into which the knurled screw 43 is inserted, and are disposed at positions spaced apart from each other by 120 degrees. Note that the protrusions 35e, 35f are sealed.

[0023] The second disk portion 62 has a common opening 621 formed to face the branch flow inlet 54, and branch openings 622a and 622b formed to face the branch flow outlets 55a and 55b. In addition, a recess 620 is formed in the second disk portion 62 to form the main flow path of the branch flow path 53. The common opening 621, the branch openings 622a and the branch openings 622b are open on the bottom surface of the recess 620. That is, the recess 620 is shaped so that a flow path from one common opening 621 branches to have the branch opening 622a or the branch opening 622b. In addition, a partition wall 623 is formed on the back surface side of the first disk portion 61 in correspondence with the recess 620, and the first disk portion 61 and the second disk portion 62 are fixed together, whereby the partition wall 623 and the recess 620 form the branch flow path 53.

[0024] Further, the second disk portion 62 has a calibration gas recess 624 for forming the calibration gas inlet passage 46 formed below the screw hole 47. The first disk portion 61 also has a calibration gas partition 625 formed in correspondence with the calibration gas recess 624 for forming the calibration gas inlet passage 46. When the first disk portion 61 and the second disk portion 62 are fixed together, the calibration gas partition 625 and the calibration gas recess 624 form the calibration gas inlet passage 46. As described above, the calibration gas inlet passage 46 passes through the first disk portion 61 and the second disk portion 62, and communicates with the calibration gas opening 56 that opens at the tip of the first protruding portion 35d.

[0025] The entire flow path of the gas detector 1 having the switching unit 40 will be further described with reference to the schematic diagram shown in FIG. 6. As shown in FIG. 6, a common flow path 50 communicating with the gas inlet 12 and the opening 33c is formed in the case 10. A first flow path 51 and a second flow path 52 are also provided in the case 10. The flow path 51 communicates with the opening 33a, and the flow path 52 communicates with the opening 33b. In FIG. 6, the openings 33a, 33b, and 33c connected to the flow paths are typically indicated by white circles (◯), and the openings 33d, 33e, and 33f not connected to the flow paths are typically indicated by black circles (●). A branch flow path 53 is formed in the switching unit 40, and the branch flow path inlet 54 of the protruding portion 35c is connected to the common flow path 50 via the opening 33c, and the branch flow path outlets 55a and 55b of the protruding portions 35a and 35c are connected to the first flow path 51 and the second flow path 52 via the openings 33a and 33b, respectively. In this case, the protruding portion 35d of the calibration gas inlet passage 46 is connected to an opening 33d that is not connected to any flow passage.

[0026] Each of the first flow path 51 and the second flow path 52 includes two sensors 71-74 for detecting gas, and flow sensors 75a, 75b for detecting the gas flow rate in the flow path. A capillary 76a (flow rate regulator) is provided between the branching portion of the branch flow path 53 and the branch flow path outlet 55a, and a capillary 76b (flow rate regulator) is also provided downstream of the flow sensor 75b in the second flow path.

[0027] In this embodiment, the sensors 71 to 74 are provided to detect different gas species, but may detect the same gas species. In this embodiment, two sensors (sensors 71, 72 and sensors 73, 74) are provided for the first flow path 51 and the second flow path 52, but one may be provided for each flow path. Downstream of the flow sensors 75a and 75b, the first flow path 51 and the second flow path 52 merge again and communicate with the discharge-side common flow path 53. A pump 77 is provided in the discharge-side common flow path 53.

[0028] During normal operation of the gas detector 1, gas introduced from the gas inlet 12 is sucked by the pump 77 while its flow rate is controlled by the capillary 76, passes through the common flow path 50 in the case 10, flows into the branch flow path 53 in the switching unit 40 through the opening 33c, and flows from the branch flow path outlets 55a, 55b through the openings 33a, 33b into the first flow path 51 and the second flow path 52. The gas that has flowed into the first flow path 51 and the second flow path 52 is discharged from the discharge port 13 via the discharge-side common flow path 53. If the gas in the first flow path 51 and the second flow path 52 contains a predetermined gas component, it is detected by the sensors 71 to 74.

[0029] The gas calibration operation of the gas detector 1 having such a switching unit 40 will be further described with reference to the schematic diagram shown in FIG. 7. When introducing a calibration gas, first, the knurled screw 43 is loosened, and the cylindrical portion 42 is gripped with the knurled screw 43 inserted into the screw hole to move the switching unit 40 away from the case 10 by a predetermined distance. As a result, the protruding portion 35 of the second disk portion 62 of the switching unit 40 is pulled out from the opening 33. In this state, the switching unit 40 is rotated 60° to the right and the knurled screw 43 is tightened again, so that the protruding portion 35d in which the calibration gas inflow path 46 is formed is inserted and fixed in the opening 33a. As a result, the first flow path 51 is connected to the calibration gas inlet 45 as shown in FIG. 7. On the other hand, as the switching unit 40 rotates, the branch flow path inlet 54 connected to the common flow path 50 is connected to the opening 33f, and the branch flow path outlets 55a and 55b are connected to the openings 33e and 33f, respectively. As a result, the calibration gas flowing in from the calibration gas inlet 45 is introduced into the first flow passage 51, making it possible to perform gas calibration of only the sensors 71, 72 in the first flow passage 51.

[0030] On the other hand, as shown in Fig. 8, when the protrusion 35d on which the calibration gas inlet 45 is formed is inserted into the opening 33b by rotating the switching part 40 60° to the left, the second flow path 52 is connected to the calibration gas inlet 46 as shown in Fig. 8. In this case, the gas calibrated from the calibration gas inlet 45 is introduced from the calibration gas inlet 46 only into the second flow path 52, and only the sensors 73, 74 of the second flow path 52 can perform gas calibration.

[0031] In this manner, the gas detector 1 is configured to include the switching unit 40 in the middle of the flow path, so that in this embodiment, even if the gas detector has a plurality of flow paths branched from one common gas inlet, it is possible to easily perform gas calibration of the sensor for each flow path. In this case, the common flow path 50 and the branch flow paths 53 can also be sealed by rotating the switching unit 40, so that it is possible to prevent gas from being mixed into the first flow path 51 or the second flow path 52. In this case, since the flow paths can be switched by rotating the switching unit 40, it is preferable that the flow paths can be easily switched with a simple configuration.

[0032] However, in such a gas detector 1, when the switching unit 40 rotates, it is possible that the rotation will stop at a position where each protrusion 35 is not completely inserted into each opening 33 of the case 10, resulting in a gas leak at the joint of the flow path in the switching unit 40.

[0033] In order to prevent such gas leakage, in this embodiment, signs (sign portions) 38 indicating the positions of the calibration gas protrusion 44 during gas calibration and in normal operation are formed around the mounting portion 32 of the case 10 as shown in Fig. 9. There are three signs 38: 38d indicating the position in normal operation, 38a indicating the position when the first flow path 51 is selected during gas calibration, and 38b indicating the position when the first flow path 51 is selected during gas calibration, all of which protrude from the case 10. With these signs 38, it is possible to visually confirm how far the switching portion 40 should be rotated when switching between operations, and gas leakage can be easily prevented.

[0034] In addition, gas may leak if the knurled screw 43 is not tightened properly after the switching unit 40 is switched, or if normal operation is attempted with the switching unit 40 set to the gas calibration operation position. In order to prevent such gas leakage, in this embodiment, as shown in FIG. 2, a fitting portion 22 that fits into the calibration gas protrusion 44 is formed on the cover 20 side. If normal operation is attempted with the switching unit 40 set to the gas calibration operation position and the cover 20 is closed, the calibration gas protrusion 44 cannot fit into the fitting portion 22 and comes into contact with it, so that the cover 20 cannot be closed. Specifically, the fitting portion 22 is made of a pair of walls 22a, 22b that protrude from the back surface of the cover 20 toward the back side. One ends 23a, 23b of the pair of walls 22a, 22b are spaced apart from each other at a distance that is approximately the same as the outer diameter of the calibration gas protrusion 44. If the calibration gas protrusion 44 is in the correct position when the cover 20 is closed, the calibration gas protrusion 44 is disposed at the spaced apart position of the one ends 23a, 23b and fits into the fitting portion 22. In this manner, in this embodiment, if the calibration gas protrusion 44 is not in the correct position, it cannot fit into the fitting portion 22 and the cover 20 cannot be closed, so that a warning can be given to the user. This makes it possible to prevent gas leakage at the joint of the flow paths in the switching portion 40.

[0035] Furthermore, in this embodiment, the other ends 24a, 24b of the pair of wall portions 22a, 22b are spaced apart at a distance that is approximately the same as the outer diameter of the knurled screw 43. If the knurled screw 43 is in the correct position when the cover 20 is closed, the knurled screw 43 is disposed at the spaced apart position of the other ends 24a, 24b and fits into the fitting portion 22. In this manner, in this embodiment, the fitting portion 22 fits into not only the calibration gas protrusion 44 but also the knurled screw 43, so that the cover 20 cannot be closed even if the knurled screw 43 is not tightened properly, and the user can be alerted. This makes it possible to further prevent gas leakage at the joint of the switching portion 40. The shape of the fitting portion 22 is not particularly limited as long as it fits into the calibration gas protrusion 44 and / or the knurled screw 43 when the cover 20 is closed. The ends 23a, 23b and the other ends 24a, 24b of the pair of walls 22a, 22b may not be provided to engage with the calibration gas projection 44 and / or the knurled screw 43, but may be provided to engage with each separately.

[0036] Furthermore, in this embodiment, the capillaries 76a and 76b are arranged to configure the gas detector 1 so that the flow rate balance in the first flow path 51 and the second flow path 52 is lost when gas leakage occurs at the junction of the flow paths in the switching unit 40. In this case, if there is no gas leakage at the junction of the switching unit 40, the same amount of gas flows through both the first flow path 51 and the second flow path 52 under normal circumstances. On the other hand, if gas leakage occurs at the junction of the switching unit 40, the flow rate balance between the first flow path 51 and the second flow path 52 is lost in this embodiment because the capillaries 76a and 76b are provided on one side upstream of the junction and the other side downstream of the junction in each flow path. When the flow rate balance is lost in this way, it is possible to determine that there is a leak when the difference in flow rates detected by the two flow sensors 75a and 75b becomes greater than a predetermined value. Even during gas calibration, for example during the gas calibration operation of the first flow path 51, the flow sensor 75b is sealed and the flow rate should be 0. However, if the flow rate of the flow sensor 75b becomes greater than 0 in that case, an error can be detected as a gas leak at the junction of the flow paths in the switching section 40.

[0037] In this way, by providing a capillary upstream of the junction of the switching unit 40 in one of the multiple flow paths and providing a capillary downstream of the junction of the switching unit 40 in the other flow path, if a leak occurs at the junction, the flow rate balance will be disrupted, making it possible to detect the flow rate difference in the flow paths early and prevent gas leakage early.

[0038] The present invention is not limited to the above-mentioned embodiment. For example, in the above-mentioned embodiment, only the first flow path 51 and the second flow path 52 are shown, but the number of flow paths is not limited to this, and the switching part may have three or more flow paths. In addition, the shape of the switching part is disk-shaped, but is not limited to this. For example, the switching part may be polygonal according to the number of flow paths, and fixed to the case 10 by the knurled screw 43 as in the present embodiment, while the knurled screw 43 is loosened, the case 10 and the polygonal switching part are separated from the case 10 by a predetermined distance, and the switching part is rotated according to the polygonal shape around the knurled screw 43 and fixed to the case 10 again. That is, even if the switching part 40 is not circular in front view, the switching part 40 can be rotated to change the opening position relative to the case 10 so as to switch the connection between the branch flow path inlet 54 and the branch flow path outlet 55 of the branch flow path 53 and the opening of the calibration gas inlet 46 and the opening 33 of the first flow path 51 and the second flow path 52, thereby obtaining the same effect as the above-mentioned embodiment.

[0039] In the above-described embodiment, a capillary is provided as the flow rate adjusting section, but the flow rate adjusting section is not limited to a capillary, and a known flow rate regulator (such as a valve) can be used.

[0040] In the above-described embodiment, gas calibration was performed by introducing a calibration gas into each flow path. However, when performing gas calibration with the same gas simultaneously for all sensors, it is also possible to set the switching unit 40 in the same position as during normal operation and introduce the calibration gas from the gas inlet 12 so that the calibration gas is introduced into the first flow path 51 and the second flow path 52.

[0041] The above-described embodiment and modifications are described for the purpose of facilitating understanding of the present invention, and are not described for the purpose of limiting the present invention. Therefore, the elements disclosed in the above embodiment and modifications are intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Explanation of symbols]

[0042] 1 Gas detector 10 Cases 11 Bottom side 12 Gas inlet 13 Gas exhaust port 13 Outlet 14 Rotational Axis 20 Cover 22 Fitting part 30 front 31 Display section 33 Aperture 34 Screw holes 35 Protrusion 38 Sign 40 Switching section 41 Disc Club 42 Cylindrical section 43 Knurled screw 44 Calibration gas protrusion 45 Calibration gas inlet 46 Calibration gas inlet 47 Screw hole 50 Common flow path 51 First Channel 52 Second flow path 53 Branch Channel 53 Discharge common flow path 54 Branch flow inlet 55 Branch flow outlet 61 First Disc 62 Second Disc 71~74 Sensor 75 Flow Sensor 76 Pump 77 Capillary

Claims

1. A plurality of flow paths each having one or more sensors disposed therebetween; a branch flow path connected at one end to one gas inlet and branched into two or more at the other end; a calibration gas flow path into which a calibration gas flows; A gas detection device comprising a flow path forming section in which the branch flow path and the calibration gas flow path are formed, The flow path forming portion is a state in which the plurality of flow paths and the branch flow path are connected; the flow path forming unit is configured to be capable of switching between a state in which the calibration gas flow path is connected to one of the plurality of flow paths, The gas detector comprises a case; The case has the plurality of flow paths therein, an opening of the branch flow path and an opening of the calibration gas flow path are formed on a joint surface of the flow path forming portion and the case, The case has a joint surface with the flow path forming portion, and openings of the plurality of flow paths are formed in the joint surface, a flow path forming portion configured to change an opening position of the flow path forming portion so as to switch the connection between the opening of the branch flow path and the opening of the calibration gas flow path and the opening of the multiple flow paths.

2. Among the plurality of flow paths, A flow rate adjusting unit is provided in one of the flow paths, In the other flow path, another flow rate adjusting unit is provided downstream of the branch point of the branch flow path corresponding to the other flow path.

2. The gas detector according to claim 1.

3. a calibration gas protrusion having a calibration gas inlet communicating with the calibration gas flow path formed therein; The gas detector has a cover that covers at least the calibration gas protrusion, 3. The gas detector according to claim 1, wherein an engagement portion is formed on the inside of said cover, which is adapted to engage with said calibration gas protrusion when said cover is closed.

4. 4. The gas detector according to claim 3, further comprising a sign portion for indicating the position of said calibration gas protrusion during normal operation and during calibration operation.

5. The gas detector according to any one of claims 1 to 4, characterized in that the flow path forming portion is made of a disk-shaped disk portion, and the connection state is switched by rotating the disk portion on its center to change the position of the opening.

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