Gas concentration measuring device

Abstract

A gas concentration measurement device (10) is provided with a case (20), a measurement instrument (30), a gas permeable membrane (40), and a driving body (50). The case (20) is provided with an inner space (200) surrounded by water-proof walls and an opening (220) that is provided in the wall and enables the inner space to communicate with the outside of the case (20). The measurement instrument (30) is disposed in the inner space (200) and measures the concentration of a gas. The gas permeable membrane (40) blocks the opening (220), transmits a gas, and does not transmit moisture. The driving body (50) vibrates the gas permeable membrane (40).

Description

[Technical Field]

[0001] The present invention relates to a technique for measuring the concentration of a gas in a liquid such as water. [Background technology]

[0002] Currently, various sensors have been devised to measure dissolved gases in water, for example, to measure the acidity of seawater, measure the amount of carbon dioxide absorbed by seaweed beds, manage the carbon dioxide concentration in the culture medium during algae cultivation, and detect leaks in seafloor carbon dioxide capture (CCS).

[0003] For example, a device for measuring the concentration of carbon dioxide dissolved in seawater is described in Patent Document 1. The measuring device in Patent Document 1 includes a seawater tank, a pump, a measuring cell, and a pipe circuit.

[0004] The seawater tank, the pump, and the measurement cell are connected by a pipe circuit. The pump circulates seawater from the seawater tank through the pipe circuit. This supplies the seawater to the measurement cell, which then measures the carbon dioxide concentration in the seawater. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 8-505218 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the device described in Patent Document 1 requires seawater to be pumped up, stored in a tank, and then circulated using a pump. This makes the device large. Furthermore, the device described in Patent Document 1 cannot easily measure the target gas.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a small-sized gas concentration measuring device that can easily measure the concentration of a gas to be measured. [Means for solving the problem]

[0008] The gas concentration measurement device of the present invention includes a housing, a measuring device, a gas-permeable membrane, and a driver. The housing includes a waterproof wall, an internal space surrounded by the wall, and an opening provided in the wall that allows the internal space to communicate with the outside of the housing. The measuring device is disposed in the internal space and measures the concentration of gas. The gas-permeable membrane closes the opening, allowing gas to pass through but not moisture. The driver vibrates the gas-permeable membrane.

[0009] With this configuration, the gas dissolved in the water can move through the gas-permeable membrane into the internal space of the housing, achieving gas equilibrium (gas-liquid equilibrium) between the internal space of the housing and the water. The vibration of the gas-permeable membrane accelerates the rate at which the gas-liquid equilibrium state is reached. Therefore, the gas concentration in the water can be measured simply by placing the device in the target water, and no tank or other equipment is required, minimizing the device's size. [Effects of the Invention]

[0010] According to the present invention, a small-sized gas concentration measuring device that can easily measure the concentration of a gas to be measured can be realized. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing the configuration of a gas concentration measuring device according to the first embodiment. [Figure 2] FIG. 2(A) is an external perspective view of the gas concentration measurement device according to the first embodiment, and FIG. 2(B) is an exploded perspective view of the gas concentration measurement device according to the first embodiment. [Figure 3] FIG. 3 is a functional block diagram of the gas concentration measuring device according to the first embodiment. [Figure 4] 4(A) and 4(B) are enlarged cross-sectional side views showing the vibration state of the gas permeable membrane. [Figure 5]FIG. 5 is a side cross-sectional view showing an example of how the gas concentration measuring device is used. [Figure 6] FIG. 6 is a graph showing an example of the transition of the carbon dioxide concentration in the internal space of the housing in the configuration of the present invention and the comparative configuration. [Figure 7] FIG. 7 is a functional block diagram of a gas concentration measurement device having a function of transmitting detection data. [Figure 8] FIG. 8 is a cross-sectional view showing the configuration of a gas concentration measuring device according to the second embodiment. [Figure 9] FIG. 9 is a cross-sectional view showing the configuration of a gas concentration measuring device according to the third embodiment. [Figure 10] FIG. 10 is an exploded perspective view of the gas concentration measuring device according to the third embodiment. [Figure 11] 11(A), 11(B), 11(C), and 11(D) are plan views showing various aspects of the driver. [Figure 12] 12(A), 12(B), and 12(C) are plan views showing various embodiments of the housing and the gas-permeable membrane. DETAILED DESCRIPTION OF THE INVENTION

[0012] [First embodiment] A gas concentration measurement device according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of the gas concentration measurement device according to the first embodiment. FIG. 2(A) is an external perspective view of the gas concentration measurement device according to the first embodiment, and FIG. 2(B) is an exploded perspective view of the gas concentration measurement device according to the first embodiment. FIG. 3 is a functional block diagram of the gas concentration measurement device according to the first embodiment.

[0013] As shown in Figures 1, 2(A), 2(B), and 3, the gas concentration measurement device 10 includes a housing 20, a measuring device 30, a gas permeable membrane 40, a driver 50, a detection circuit 61, a battery 62, and a driver 63.

[0014] (Housing 20) In this embodiment, the housing 20 has an internal space 200 surrounded by six walls. For example, the housing 20 is composed of a box body 21 and a flat plate 22. The box body 21 has a recess surrounded by five walls. The internal space 200 of the housing 20 is formed by covering the recess of the box body 21 with the flat plate 22.

[0015] An opening 220 is formed in the flat plate 22. The opening 220 is circular when viewed in a direction perpendicular to the flat plate 22, and penetrates the flat plate 22 in the thickness direction.

[0016] As a result, the internal space 200 of the housing 20 can communicate with the outside of the housing 20 through the opening 220 .

[0017] The walls of the housing 20 (the box body 21 and the flat plate 22) are made of a waterproof material (a material that does not allow moisture to pass through). In this case, the walls of the housing 20 are preferably made of a material that has excellent rust resistance. For example, the walls of the housing 20 are made of a metal such as aluminum or stainless steel, or a polymer material.

[0018] (gas permeable membrane 40, driver 50) The gas-permeable membrane 40 is a membrane that allows gas (gas to be measured) to pass through but is substantially impermeable to moisture. For example, the gas-permeable membrane 40 is a membrane made of a porous polymer film (such as expanded PTFE) or an amorphous polymer film (such as amorphous fluoropolymer). The thickness of the gas-permeable membrane 40 is preferably 150 μm or less. Note that "substantially impermeable to moisture" does not necessarily mean that the membrane is completely impermeable to moisture, but also includes a membrane that allows only a small amount of moisture to pass through within a practical range.

[0019] The gas-permeable membrane 40 is disposed in the opening 220 of the housing 20. More specifically, the gas-permeable membrane 40 is disposed so as to close the opening 220. The gas-permeable membrane 40 is fixed to the outer surface of the flat plate 22.

[0020] In this way, the gas-permeable membrane 40 blocks the opening 220 of the housing 20, thereby preventing moisture from entering the internal space 200 of the housing 20 while enabling gas to move between the internal space 200 of the housing 20 and the outside of the housing 20.

[0021] The driver 50 can assume a variety of shapes by applying electricity or heat. The driver 50 may also generate vibrations. For example, the driver 50 may be a piezoelectric body, a bimetal, a shape memory alloy, or the like.

[0022] The driver 50 is disposed on the gas permeable membrane 40. The driver 50 is disposed so as to overlap a portion of the gas permeable membrane 40. Specifically, in the cases of FIGS. 1, 2(A), and 2(B), the driver 50 is a circular piezoelectric element. The driver 50 is disposed in the center of the gas permeable membrane 40 so that its circular surface is parallel to the plane of the gas permeable membrane 40. In this case, the driver 50 may be disposed directly on the gas permeable membrane 40, or a separate member may be disposed between the driver 50 and the gas permeable membrane 40, which can transmit stress from the driver 50 to the gas permeable membrane 40.

[0023] Because the planar shape (circular) of the driver 50 is smaller than the planar shape of the gas permeable membrane 40, the driver 50 covers only a portion of the gas permeable membrane 40. Therefore, the remaining areas of the gas permeable membrane 40 can maintain gas permeability.

[0024] The shape of the driver 50 changes in response to a drive control signal (described in detail later) from the control circuit 631. For example, in the cases of Figures 1, 2(A), and 2(B), the driver 50 expands and contracts in a direction substantially parallel to the plane of the gas permeable membrane 40 in response to the drive control signal.

[0025] The stress caused by the expansion and contraction of the driver 50 is applied to the gas permeable membrane 40 on which the driver 50 is disposed, causing the gas permeable membrane 40 to expand and contract and vibrate.

[0026] 4(A) and 4(B) are enlarged cross-sectional side views showing the vibration state of the gas-permeable membrane. As shown in Fig. 4(A), when the driver 50 expands, the gas-permeable membrane 40 curves and bulges toward the surface on which the driver 50 is placed. As shown in Fig. 4(B), when the driver 50 contracts, the gas-permeable membrane 40 curves and bulges toward the surface opposite the surface on which the driver 50 is placed.

[0027] By repeatedly expanding and contracting the driver 50 using a drive control signal, the gas permeable membrane 40 vibrates so that the center of the gas permeable membrane 40 is displaced in a direction perpendicular to the plane of the gas permeable membrane 40 .

[0028] The ratio of the area where the driver 50 overlaps with the gas permeable membrane 40 is determined appropriately based on the efficiency with which the driver 50 vibrates the gas permeable membrane 40 (the ratio of the magnitude of the stress applied to the gas permeable membrane 40 by the driver 50 to the driving energy supplied to the driver 50) and the efficiency with which the gas permeable membrane 40 allows gas to pass through (gas permeability per unit time).

[0029] (measuring device 30, detection circuit 61, battery 62, driving device 63) Measuring device 30, detection circuit 61, battery 62, and drive device 63 are disposed inside housing 20, i.e., in internal space 200 of housing 20. Also disposed in internal space 200 of housing 20 are wiring conductor 281, wiring conductor 282, circuit board 291, and circuit board 292.

[0030] The measuring device 30 includes a sensor case 31, a light source 32, an infrared sensor 33, and an optical filter .

[0031] The sensor case 31 is a box-like body and has an internal space 300. The sensor case 31 is smaller than the housing 20. An opening 320 is formed in one wall of the sensor case 31. The opening 320 is circular when viewed in a direction perpendicular to the wall in which the opening 320 is formed, and penetrates the wall in the thickness direction.

[0032] As a result, the internal space 300 of the sensor case 31 communicates with the outside of the sensor case 31 , that is, with the internal space 200 of the housing 20 , via the opening 320 .

[0033] The light source 32, the infrared sensor 33, and the optical filter 34 are disposed inside the sensor case 31 (internal space 300).

[0034] More specifically, the light source 32 is disposed on one wall of the sensor case 31 that is perpendicular to the wall on which the opening 320 is formed. The infrared sensor 33 is disposed on a wall of the sensor case 31 that faces the wall on which the light source 32 is disposed. The light receiving surface of the infrared sensor 33 faces the light source 32.

[0035] The optical filter 34 covers the light receiving surface of the infrared sensor 33. The optical filter 34 is a filter that passes infrared light and blocks other frequencies.

[0036] With this configuration, the measuring instrument 30 realizes a carbon dioxide measurement sensor using the non-dispersive infrared absorption method (NDIR). That is, the measuring instrument 30 outputs a measurement signal corresponding to the concentration of carbon dioxide in the internal space 300. However, the measuring instrument 30 is not limited to a carbon dioxide measurement sensor using the non-dispersive infrared absorption method (NDIR).

[0037] Meter 30 is mounted on circuit board 292 and fixed to housing 20. At this time, meter 30 is positioned so that opening 320 of sensor case 31 faces opening 220 of housing 20.

[0038] Detection circuit 61 is composed of multiple electronic circuit components 611. Detection circuit 61 is connected to measuring instrument 30 by wiring conductor 281. Detection circuit 61 detects the carbon dioxide concentration from the measurement signal output by measuring instrument 30, and generates carbon dioxide concentration detection data.

[0039] The detected data of the carbon dioxide concentration is stored, for example, in a storage medium provided in the detection circuit 61. This makes it possible to check the detected data of the carbon dioxide concentration after the gas concentration measuring device 10 is collected.

[0040] A battery 62 powers the meter 30 and the detection circuitry 61 .

[0041] 3, the driving device 63 functionally includes a control circuit 631 and a battery 632. The battery 632 supplies power to the control circuit 631.

[0042] The control circuit 631 is configured with electronic components such as ICs. The control circuit 631 receives power from a battery 632 and generates a drive control signal for the driver 50. The control circuit 631 outputs the drive control signal to the driver 50. The drive control signal is an AC signal such as a sine wave or square wave.

[0043] The control circuit 631 of the driving device 63 is connected to the driving body 50 by the wiring conductor 282. As a result, the control circuit 631 supplies a drive control signal to the driving body 50 through the wiring conductor 282.

[0044] The detection circuit 61, the battery 62, and the drive device 63 are mounted on a circuit board 291, which is fixed to the housing 20.

[0045] Circuit board 291 and circuit board 292 are connected by wiring conductor 281. This wiring conductor 281 realizes the supply of power to measuring device 30 and the transmission of measurement signals from measuring device 30 to detection circuit 61.

[0046] (Use of gas concentration measuring device 10) 5 is a side cross-sectional view showing an example of how the gas concentration measuring device is used. As shown in FIG. 5, the gas concentration measuring device 10 is placed in water in which the gas to be measured is dissolved. As described above, the opening 220 of the housing 20 is closed by the gas permeable membrane 40, so the internal space 200 of the housing 20 is sealed against moisture. Therefore, the gas concentration measuring device 10 can prevent moisture from entering the internal space 200.

[0047] Meanwhile, the internal space 200 of the housing 20 and the water are separated by the gas-permeable membrane 40. This allows gas to move between the water and the internal space 200 of the housing 20. Then, a gas-liquid equilibrium state is reached between the water and the internal space 200 of the housing 20 over a predetermined period of time depending on the gas permeability of the gas-permeable membrane 40.

[0048] Henry's law states that when a dilute solution containing a volatile solute is in equilibrium with a gas phase, the partial pressure of the solute in the gas phase is proportional to its concentration in the solution. Therefore, if the internal space 200 of the housing 20 and the water are in a gas-liquid equilibrium state, the gas concentration in the internal space 200 will theoretically be the same as the gas concentration in the water.

[0049] Taking advantage of this, the gas concentration measurement device 10 places the measuring device 30 in the internal space 200 of the housing 20, and measures the carbon dioxide concentration in the internal space 200 using the measuring device 30. In this way, the gas concentration measurement device 10 can measure the carbon dioxide concentration in water.

[0050] Conventional gas concentration measuring devices that do not vibrate the gas-permeable membrane require a long time to reach gas-liquid equilibrium after being immersed in water, making it difficult to quickly and easily measure the carbon dioxide concentration in water.

[0051] However, in the gas concentration measuring device 10, the gas permeable membrane 40 is vibrated by the driver 50, thereby improving the efficiency of gas (carbon dioxide) movement through the gas permeable membrane 40. As a result, the gas concentration measuring device 10 quickly reaches a gas-liquid equilibrium state.

[0052] Figure 6 is a graph showing an example of the transition of carbon dioxide concentration in the internal space of the housing for the present invention's configuration and a comparative configuration. In Figure 6, the solid line shows the characteristics of the present invention's configuration, and the dotted line shows the characteristics of the comparative configuration. The comparative configuration uses a gas-permeable membrane with the same area and gas permeability as the present invention's configuration, but the gas-permeable membrane is not vibrated.

[0053] As shown in FIG. 6, with the configuration of the present invention, the carbon dioxide concentration in the internal space 200 of the housing 20 reaches the carbon dioxide concentration in water more quickly than with the comparative configuration.

[0054] This allows the gas concentration measuring device 10 to quickly and easily measure the carbon dioxide concentration in water.

[0055] In this configuration, the housing 20 is, for example, 10 cm 3 ~100cm 3 In other words, the gas concentration measurement device 10 can be made significantly smaller than conventional configurations that use tanks or the like.

[0056] Furthermore, by making the housing 20 smaller, the area of ​​the gas permeable membrane 40 is reduced, but the decrease in the gas permeability of the gas permeable membrane 40 due to vibration can be suppressed.

[0057] In this way, the gas concentration measuring device 10 can quickly and easily measure the carbon dioxide concentration in water while achieving a small size.

[0058] In the above-described configuration, the driver 50 is disposed directly on the gas permeable membrane 40. However, the driver 50 may not be disposed directly on the gas permeable membrane 40, and may vibrate the gas permeable membrane 40 indirectly, for example, via another member. However, by disposing the driver 50 directly on the gas permeable membrane 40, the driver 50 functions as a support for the gas permeable membrane 40. This makes it possible to prevent damage to the gas permeable membrane 40, such as tearing, when the gas permeable membrane 40 vibrates. The driver 50 may be connected directly to the gas permeable membrane 40. However, the driver 50 may not be connected directly to the gas permeable membrane 40, and may vibrate the gas permeable membrane 40 indirectly, for example, via another member.

[0059] Furthermore, the drive control signal may be supplied to the driver 50 before or after the gas concentration measurement device 10 is placed underwater. When the gas concentration measurement device 10 is placed underwater, the timing and time for supplying the drive control signal to the driver 50 can be achieved by, for example, presetting the drive start time (the time elapsed since the gas concentration measurement device 10 was started or placed underwater), the drive time, etc. This allows the gas concentration measurement device 10 to vibrate the gas permeable membrane 40 at an appropriate time even when it is underwater.

[0060] It is also possible to install an ultrasonic receiving sensor or the like in the housing 20 and use ultrasonic waves from the outside to control the supply of a drive control signal to the driver 50. Furthermore, it is also possible to install a water pressure sensor or the like in the housing 20 and control the supply of a drive control signal to the driver 50 based on the detected value of the water pressure sensor.

[0061] The detected data can also be transmitted to an external device. Fig. 7 is a functional block diagram of a gas concentration measurement device equipped with a function for transmitting detected data. As shown in Fig. 7, a gas concentration measurement device 10T equipped with a function for transmitting detected data further includes an antenna 68 and a communication cable 69 in addition to the components of the gas concentration measurement device 10 described above.

[0062] For example, when the gas concentration measuring device 10T is used underwater (similar use state to that shown in FIG. 5), the antenna 68 is placed on a buoy or the like floating on the water surface. The communication cable 69 is waterproof. The communication cable 69 connects the antenna 68 to the detection circuit 61. The detection circuit 61 outputs detection data (detection data based on a measurement signal of the gas concentration) to the antenna 68 via the communication cable 69. The antenna 68 wirelessly transmits the detection data to an external analysis device or the like. Note that the method of transmitting the detection data is not limited to this.

[0063] [Second embodiment] A gas concentration measurement device according to a second embodiment of the present invention will be described with reference to the drawings. Fig. 8 is a cross-sectional view showing the configuration of the gas concentration measurement device according to the second embodiment.

[0064] 8, the gas concentration measurement device 10A according to the second embodiment differs from the gas concentration measurement device 10 according to the first embodiment in the arrangement of the gas permeable membrane 40 in the housing 20. The other configuration of the gas concentration measurement device 10A is the same as that of the gas concentration measurement device 10, and a description of similar parts will be omitted.

[0065] In the gas concentration measuring device 10A, the gas permeable membrane 40 is disposed on the surface of the flat plate 22 of the housing 20 that faces the internal space 200.

[0066] With this configuration, the gas concentration measurement device 10A, like the gas concentration measurement device 10, can quickly and easily measure the carbon dioxide concentration in water while achieving a small size.

[0067] Furthermore, in gas concentration measurement device 10A, the joint between gas permeable membrane 40 and housing 20 is on the inside of housing 20. Therefore, when gas concentration measurement device 10A is placed in water, the joint between gas permeable membrane 40 and housing 20 can be prevented from coming into contact with external foreign matter and peeling off.

[0068] [Third embodiment] A gas concentration measurement device according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 9 is a cross-sectional view showing the configuration of the gas concentration measurement device according to the third embodiment. Fig. 10 is an exploded perspective view of the gas concentration measurement device according to the third embodiment.

[0069] 9 and 10, a gas concentration measurement device 10B according to the third embodiment differs from the gas concentration measurement device 10 according to the first embodiment in that a mesh material 60 is added. Other configurations of the gas concentration measurement device 10B are the same as those of the gas concentration measurement device 10, and a description of similar parts will be omitted.

[0070] The mesh material 60 is made of, for example, stainless steel or aluminum. The mesh material 60 may be a flat plate with a plurality of holes, such as a punched metal.

[0071] The mesh material 60 is disposed so as to cover the gas permeable membrane 40 from the outer surface side.

[0072] With this configuration, the gas concentration measurement device 10 can quickly and easily measure the carbon dioxide concentration in water while achieving a small size, similar to the gas concentration measurement device 10.

[0073] Furthermore, in the gas concentration measuring device 10B, the mesh material 60 can prevent the gas permeable membrane 40 from being damaged due to contact with external foreign matter.

[0074] [Various aspects of the driver] 11(A), 11(B), 11(C), and 11(D) are plan views showing various aspects of the driver.

[0075] 11(A), the driver 50X1 is a flat strip (having a longitudinal direction). The driver 50X1 is arranged along the diameter direction of the gas permeable membrane 40. The driver 50X1 expands and contracts along the longitudinal direction. The driver 50X1 is preferably made of piezoelectric ceramics, polylactic acid, bimetal, or the like.

[0076] In the case of FIG. 11(B), the driver 50X2 is composed of two flat membrane strips (shaped with a longitudinal direction). The two strips are perpendicular to each other and are arranged along the diameter direction of the gas permeable membrane 40. The two strips constituting the driver 50X2 expand and contract along the longitudinal direction. The driver 50X2 is preferably made of piezoelectric ceramics, polylactic acid, bimetal, or the like.

[0077] In the case of FIG. 11(C), the driver 50X3 is composed of multiple individual drivers. The multiple individual drivers are rectangular in plan view. The multiple individual drivers are arranged at predetermined intervals along the circumferential direction of the gas permeable membrane 40. The intervals between the individual drivers are preferably uniform, but do not have to be uniform. The number of individual drivers is not limited to four. The multiple individual drivers expand and contract in a direction parallel to the direction from the outer circumferential edge toward the center of the gas permeable membrane 40 on which they are arranged.

[0078] In the case of Fig. 11(D), the driver 50X1 expands and contracts along the longitudinal direction. The driver 50X1 is preferably made of polylactic acid or a bimetal. The driver 50X4 is a flat membrane having a circular ring shape. The driver 50X4 is disposed along the outer periphery of the gas permeable membrane 40. The driver 50X4 expands and contracts along the circumferential direction.

[0079] The above-described drivers 50X1, 50X2, 50X3, and 50X4 are each an example, and they may be combined. That is, the driver is not limited to the above-described configuration as long as it is disposed on the gas permeable membrane 40 and can vibrate the gas permeable membrane 40.

[0080] In the above description, the driver is disposed on the inner space 200 side of the gas permeable membrane 40. However, the driver may be disposed on the outer surface of the gas permeable membrane 40 (the surface opposite to the inner space 200 side). Furthermore, the driver may be disposed on both surfaces of the gas permeable membrane 40.

[0081] [Various aspects of the housing and gas-permeable membrane] 12(A), 12(B), and 12(C) are plan views showing various embodiments of the housing and the gas-permeable membrane.

[0082] 12(A), a gas concentration measuring device 10X1 includes a cylindrical housing 20X1. The gas permeable membrane 40 is disposed on an end surface of the housing 20X2 that is perpendicular to the peripheral surface of the housing 20X2.

[0083] 12(B), a gas concentration measuring device 10X2 includes a cylindrical housing 20X2. A plurality of gas permeable membranes 40X2 are disposed on the periphery of the housing 20X2.

[0084] In the case of FIG. 12(C), a gas concentration measuring device 10X3 includes a gas permeable membrane 40X3 that is rectangular in plan view.

[0085] In this way, in the gas concentration measuring device, the shape of the casing, the planar shape of the gas permeable membrane, the position of the gas permeable membrane in the casing, and the number of gas permeable membranes can be set as appropriate.

[0086] The above-described embodiments and various aspects can be combined as appropriate, and effects according to each combination can be achieved.

[0087] <1> a housing including an internal space surrounded by a waterproof wall, and an opening provided in the wall to allow the internal space to communicate with the outside of the housing; a measuring device disposed in the internal space for measuring a concentration of the gas; a gas-permeable membrane that closes the opening and allows the gas to pass through but is substantially impermeable to moisture; a driver for vibrating the gas permeable membrane.

[0088] <2> The driving body realizes a plurality of shapes by applying electricity or heating. <1> The gas concentration measuring device according to claim 1.

[0089] <3> The driving body is a piezoelectric body. <2> The gas concentration measuring device according to claim 1.

[0090] <4> The driver is a bimetal. <2> The gas concentration measuring device according to claim 1.

[0091] <5> the driver is disposed on the gas permeable membrane on the surface thereof facing the internal space; <1> ~ <4> The gas concentration measuring device according to any one of the preceding claims.

[0092] <6> The driver is a film. <1> ~ <5> The gas concentration measuring device according to any one of the preceding claims.

[0093] <7> The driver is disposed on the gas permeable membrane. <1> ~ <6> The gas concentration measuring device according to any one of the preceding claims.

[0094] <8> The driving body is a support for the gas-permeable membrane. <7> The gas concentration measuring device according to claim 1.

[0095] <9> the gas permeable membrane and the driver are disposed on the internal space side of the opening; <1> ~ <8> The gas concentration measuring device according to any one of the preceding claims.

[0096] <10> a control circuit for controlling the vibration of the driver; The control circuit the gas permeable membrane does not protrude outward from the housing beyond its position in a non-vibrating state; or the gas permeable membrane vibrates more toward the internal space than toward the exterior of the housing relative to the non-vibrating position of the gas permeable membrane, Driving the driver; <1> ~ <9> The gas concentration measuring device according to any one of the preceding claims.

[0097] <11> a first power source that supplies power to the measuring device and a second power source that supplies power to the control circuit are provided in the internal space; <10> The gas concentration measuring device according to claim 1.

[0098] <12> a first power source for supplying power to the measuring device is provided in the internal space; <1> ~ <10> The gas concentration measuring device according to any one of the preceding claims.

[0099] <13> an antenna for transmitting detection data based on the measurement signal of the gas concentration to an outside of the gas concentration measurement device; <1> ~ <12> The gas concentration measuring device according to any one of the preceding claims. [Explanation of symbols]

[0100] 10, 10A, 10B, 10T, 10X1, 10X2, 10X3: Gas concentration measuring device 20, 20X1, 20X2: Housing 21: Box body 22: Flat plate 30: Measuring instrument 31: Sensor case 32: Light source 33: Infrared sensor 34: Optical filter 40, 40X2, 40X3: Gas permeable membrane 50, 50X1, 50X2, 50X3, 50X4: Driver 60: Mesh material 61: Detection circuit 62:Battery 63: Drive unit 68: Antenna 69: Communication cable 200: Interior space 220: Opening 281, 282: Wiring conductor 291, 292: Circuit board 300: Interior space 320: Opening 611: Electronic circuit components 631: Control circuit 632:Battery

Claims

1. a housing including a waterproof wall, an internal space surrounded by the wall, and an opening provided in the wall to allow the internal space to communicate with the outside of the housing; a measuring device disposed in the internal space for measuring a concentration of the gas; a gas-permeable membrane that closes the opening and allows the gas to pass through but is substantially impermeable to moisture; a driver that vibrates the gas permeable membrane; A gas concentration measuring device comprising:

2. The driving body realizes a plurality of shapes by applying electricity or heating. The gas concentration measuring device according to claim 1 .

3. The driving body is a piezoelectric body. The gas concentration measuring device according to claim 2 .

4. The driver is a bimetal. The gas concentration measuring device according to claim 2 .

5. the driver is disposed on the gas permeable membrane on the surface thereof facing the internal space; The gas concentration measuring device according to claim 1 .

6. The driver is a film.

6. The gas concentration measuring device according to claim 1.

7. The driver is disposed on the gas permeable membrane. The gas concentration measuring device according to claim 1 .

8. The driving body is a support for the gas-permeable membrane. The gas concentration measuring device according to claim 7.

9. the gas permeable membrane and the driver are disposed on the internal space side of the opening; The gas concentration measuring device according to claim 1 .

10. a control circuit for controlling the vibration of the driver; The control circuit the gas permeable membrane does not protrude outward from the housing beyond its position in a non-vibrating state; or the gas permeable membrane vibrates more toward the internal space than toward the exterior of the housing relative to the non-vibrating position of the gas permeable membrane, Driving the driver; The gas concentration measuring device according to claim 1 .

11. a first power supply that supplies power to the measuring device and a second power supply that supplies power to the control circuit are provided in the internal space; The gas concentration measuring device according to claim 10.

12. a first power source for supplying power to the measuring device is provided in the internal space; The gas concentration measuring device according to claim 1 .

13. an antenna for transmitting detection data based on the measurement signal of the gas concentration to an outside of the gas concentration measurement device; The gas concentration measuring device according to claim 1 .

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