Gas measuring instrument

Abstract

To provide a gas measurement device which allows continuous use of a gas ingredient sorting function.SOLUTION: A gas measurement device is provided, comprising a magnetic field generation unit for generating a magnetic field, and a gas sensor for detecting the gas having passed through the magnetic field generated by the magnetic field generation unit.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present disclosure relates to a gas measuring device.

Background Art

[0002] Patent Document 1 discloses a gas detection device including a filter made of fibrous activated carbon and a MEMS gas sensor. The gas detection device has a function of separating a gas component to be detected and a gas component not to be detected by adsorbing a miscellaneous gas not to be detected by the filter. The adsorption capacity of the filter decreases in response to the adsorption of the miscellaneous gas. Therefore, the gas detection device has a heater for regenerating the adsorption capacity of the filter. The filter heated by the heater desorbs the adsorbed gas. Thereby, the adsorption capacity of the filter is regenerated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the gas detection device disclosed in Patent Document 1, periodic heat cleaning of the filter is required. However, while the heat cleaning is being performed, the gas detection device cannot detect gas. The present disclosure provides a gas measuring device that can continuously use the function of separating gas components.

Means for Solving the Problems

[0005] The gas measuring device according to one aspect of the present disclosure includes a magnetic field generation unit that generates a magnetic field, and a gas sensor that detects a gas that has passed through the magnetic field generated from the magnetic field generation unit. <000003​In this gas measuring instrument, the gas being measured by the gas sensor passes through a magnetic field generated by the magnetic field generator. At this time, paramagnetic gases are attracted by the magnetic field, while diamagnetic gases are repelled. Therefore, the gas measuring instrument can control the direction of gas travel according to the gas's magnetism, thus exhibiting a gas component sieving function. Furthermore, because the magnetic field acts indirectly on the gas, the sieving function does not deteriorate even with continuous use. Thus, this gas measuring instrument can be used continuously to sieve gas components.

[0007] In one embodiment, the magnetic field generating unit may consist of a permanent magnet. Since the magnetic field generating unit consists of a permanent magnet, it generates a magnetic field without using electricity, allowing for continuous use of the gas component sieving function with a simple configuration.

[0008] In one embodiment, a power supply unit may be provided. The magnetic field generating unit may be a coil. The power supply unit may energize the coil. The coil generates a magnetic field when energized. Therefore, in a configuration where the magnetic field generating unit is a coil energized from the power supply unit, it is possible to switch between a state in which gas components are sieved and a state in which gas components are not sieved by interrupting the energization.

[0009] In one embodiment, the system may include a signal generation unit, a control unit, an acquisition unit, and an output unit. The signal generation unit may output a synchronization signal that determines the timing. The control unit may control the power supply unit to apply a voltage or current of the magnitude determined by the control signal to the coil at the timing determined by the synchronization signal, based on the control signal that determines the magnitude of the voltage or current and the synchronization signal. The acquisition unit may acquire the detected value of the gas sensor at the timing determined by the synchronization signal. The output unit may output the detected value and the control signal in association. In this case, the gas measuring instrument can output the detected value and the synchronization signal in association.

[0010] In one embodiment, the gas measuring instrument further includes a determination unit that determines the gas type based on a pre-acquired relationship between the gas type, the detected value, and the control signal, and the detected value and control signal output by the output unit. In this case, the gas measuring instrument can determine the gas type of a mixed gas containing paramagnetic and diamagnetic gas components with different directions of propagation.

[0011] In one embodiment, the gas detector may further include a plurality of gas sensors, including a gas sensor. The plurality of gas sensors may include other gas sensors capable of detecting gas types different from those detected by the gas sensor. In this case, the gas detector can improve the accuracy of gas detection compared to a gas detector equipped with a gas sensor capable of detecting a single type of gas.

[0012] In one embodiment, the system may further include a plurality of gas sensors, each including a gas sensor. The plurality of gas sensors may be arranged along the direction of the magnetic field generated from the magnetic field generator. A paramagnetic gas is attracted in the direction of its propagation along the direction of the magnetic field. A diamagnetic gas is repelled in the direction of its propagation along the direction of the magnetic field. Therefore, the plurality of gas sensors can detect multiple types of gas components that have been filtered along the direction of the magnetic field. [Effects of the Invention]

[0013] This disclosure provides a gas measuring instrument that can continuously use a sieving function for gas components. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view showing an example of a gas measuring instrument according to the embodiment. [Figure 2] This is a schematic diagram illustrating the direction of gas travel through the magnetic field generating unit according to the embodiment. [Figure 3] Figure 3(A) is a block diagram showing an example of a gas measuring instrument according to the embodiment. Figure 3(B) shows an example of a control signal and a synchronization signal. [Figure 4] This is a schematic diagram illustrating how the direction of gas propagation changes due to the strength of a magnetic field. [Figure 5] This is a cross-sectional view showing a modified example of the gas measuring instrument according to the embodiment. [Modes for carrying out the invention]

[0015] Embodiments of this disclosure will be described below with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numeral, and redundant descriptions will not be repeated. The dimensional ratios in the drawings do not necessarily correspond to those described.

[0016] [Gas measuring instrument configuration] Figure 1 is a cross-sectional view showing an example of a gas measuring instrument 1 according to an embodiment. The gas measuring instrument 1 shown in Figure 1 is a device for measuring the components of a gas. The gas measuring instrument 1 may be provided as an electrical circuit component. For example, the gas measuring instrument 1 is a MEMS (Micro Electro Mechanical Systems) device. The gas measuring instrument 1 comprises a magnetic field generating unit 10, a power supply unit 12, a gas sensor 30, and a substrate 40.

[0017] The base material 40 defines a space within it. The base material 40 is made of a material that does not allow gas to pass through. The base material 40 has an opening at its top that communicates with the space. In this embodiment, the magnetic field generating unit 10 is a coil 11. The coil 11 is positioned to cover the opening at the top of the base material 40. The coil 11 has gaps through which gas can pass. The coil 11 and the base material 40 are joined together such that there are no other gaps through which gas can pass. As a result, the coil 11 and the base material 40 define a gas chamber 41.

[0018] The coil 11 is an air-core coil consisting of wire wound around an axial direction. The axial direction of the coil 11 extends, for example, along a direction perpendicular to the direction communicating the inside and outside of the gas chamber 41. The wire constituting the coil 11 is connected to a power supply unit 12 to which voltage or current can be applied. In this case, the direction of the magnetic field generated in the energized coil 11 coincides with the axial direction.

[0019] The gas sensor 30 is provided inside the gas chamber 41. As an example, the gas sensor 30 is provided downstream of the coil 11, that is, on the side where the gas has passed through the coil 11. The gas sensor 30 further includes a plurality of gas sensors 31, 32 including the gas sensor 30, and the gas sensors 31, 32 can detect gas species different from the gas species detected by the gas sensor 30. The gas sensors 30, 31, 32 detect the gas adhering to a predetermined surface of the gas sensor 30 after passing through the coil 11.

[0020] FIG. 2 is a schematic diagram showing the traveling direction of the gas passing through the coil 11 in FIG. 1. In FIG. 2, as an example, the coil 11 generates a magnetic field in the axial direction orthogonal to the direction communicating the inside and the outside of the gas chamber 41. The magnetic flux density in the coil 11 is highest at the center in the axial direction and lowest at both ends in the axial direction. The gas passing through the coil 11 may contain a paramagnetic gas component and a diamagnetic gas component. Paramagnetic gases are, for example, oxygen (O2), nitric oxide (NO), and nitrogen dioxide (NO2). Diamagnetic gases are, for example, water vapor (H2O), chlorine (Cl2), and carbon dioxide (CO2).

[0021] The paramagnetic gas and the diamagnetic gas are caused to change their traveling directions by the coil 11. An attractive force due to the magnetic field acts on the paramagnetic gas. The traveling direction C1 of the paramagnetic gas is attracted to a position where the magnetic flux density is high. In the present embodiment, the traveling direction C1 of the paramagnetic gas changes so as to be attracted to the center in the axial direction of the coil 11. A repulsive force due to the magnetic field acts on the diamagnetic gas. The traveling direction C2 of the diamagnetic gas is attracted to a position where the magnetic flux density is low. In the present embodiment, the traveling direction C2 of the paramagnetic gas changes so as to be attracted to both ends in the axial direction of the coil 11. [[ID=⑨]] [[ID=⑩]]

[0022] [[ID=⑪]] As shown in Figure 2, gas sensor 31 is located in region 41a within the gas chamber 41. Region 41a is set downstream of the center in the axial direction of coil 11. Region 41a is the region to which gas attracted to the center in the axial direction of coil 11 reaches. Gas sensors 30 and 32 are located in region 41b adjacent to region 41a. Region 41b is set downstream of both ends in the axial direction of the air-core coil. Region 41b is the region within the gas chamber 41 other than region 41a. Region 41b is the region to which gas attracted to both ends in the axial direction of air-core coil reaches. Regions 41a and 41b are aligned along the axial direction of coil 11. Therefore, gas sensors 30, 31, and 32 are aligned along the direction of the magnetic field generated by coil 11.

[0023] Gas sensor 31 primarily detects paramagnetic gas components whose direction of travel C1 is changed toward the center in the axial direction of coil 11. Gas sensors 30 and 32 primarily detect diamagnetic gas components whose direction of travel C2 is changed toward both ends in the axial direction of coil 11.

[0024] [Control circuit of gas measuring instrument] Figure 3(A) is a block diagram showing an example of a gas measuring instrument 1 according to an embodiment. The gas measuring instrument 1 comprises a measuring unit 2 (an example of a gas measuring instrument) and a circuit unit 3. The circuit unit 3 comprises a power supply unit 12, a signal generation unit 50, a control unit 60, an acquisition unit 70, an output unit 80, and a determination unit 90. The circuit unit 3 may be composed of, for example, an electrical circuit. The circuit unit 3 may also be composed of, for example, a general-purpose computer having an arithmetic unit such as a CPU (Central Processing Unit), a storage device such as ROM (ReadOnly Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), and a communication device.

[0025] The signal generation unit 50 outputs a control signal and a synchronization signal to the control unit 60 and the acquisition unit 70. The control signal is a signal that determines the magnitude (or potential difference) of the voltage or current that the power supply unit 12 applies to the coil 11. The synchronization signal is a signal that determines the timing of the operation of the control unit 60 and the acquisition unit 70. Based on the control signal and the synchronization signal, the control unit 60 controls the power supply unit 12 to apply a voltage or current of the magnitude determined by the control signal to the coil 11 at the timing determined by the synchronization signal. Figure 3(B) shows an example of the control signal and the synchronization signal. In Figure 3(B), the control signal is a signal corresponding to the magnitude of three types of voltages: SIG1, SIG2, and SIG3. The synchronization signal is a square wave based on an oscillator such as a crystal oscillator.

[0026] The control unit 60 outputs a signal to control the power supply unit 12 according to the control signal when it receives a predetermined number of square wave synchronization signals. For example, the control signal that changes in three stages in Figure 3(B) controls the voltage magnitude in three stages. The voltage magnitude may be controlled continuously. In this case, the control signal represents a triangular wave or a sine wave.

[0027] The acquisition unit 70 acquires the detected value detected by the gas sensor at a timing determined by the synchronization signal when it receives the synchronization signal's square wave a predetermined number of times. Therefore, the acquisition unit 70 can acquire a detected value corresponding to the change in the magnitude of the voltage or current due to the control signal. The predetermined number of times the acquisition unit 70 receives the square wave when acquiring the detected value may be greater than or equal to the number of times the control unit 60 receives the square wave when outputting the control signal. By delaying the timing of the acquisition unit 70 acquiring the detected value compared to the timing of the control unit 60 outputting the control signal, the acquisition unit 70 can acquire a detected value when a large amount of gas has passed between the coils 11 after the magnitude of the voltage or current has changed.

[0028] The output unit 80 outputs the control signal and the detected value obtained from the acquisition unit 70 in association. The determination unit 90 determines the gas type based on the previously acquired relationship between the gas type, the detected value, and the control signal, and the detected value and control signal output by the output unit 80. The combinations of gas type, detected value, and control signal are acquired in advance and stored, for example, as a gas characteristic table. The determination unit 90 refers to the gas characteristic table based on the combination output by the output unit 80 and determines the gas type.

[0029] [Gas detector operation] Figure 4 is a schematic diagram illustrating the change in the direction of gas propagation due to the strength of the magnetic field generated by coil 11. As an example, the gas to be detected is a mixed gas containing paramagnetic and diamagnetic gas components. Gas sensors 30, 31, and 32 are positioned downstream of the multiple electrodes, respectively. Gas sensor 31 is located in region 41a downstream of the center in the axial direction of coil 11. Gas sensors 30 and 32 are positioned in region 41b set downstream of both ends in the axial direction of the air-core coil.

[0030] As shown in Figure 3(B), the control unit 60 first changes the magnitude of the voltage or current applied to the coil 11 based on the control signal and the synchronization signal that determines the timing. Figure 4(A) shows the direction of gas travel through the coil 11 when the control signal is SIG1. As an example, when the control signal is SIG1, the control unit 60 does not apply voltage or current to the coil 11. Therefore, no magnetic field is generated in the coil 11. When the control signal is SIG1, the direction of travel of the paramagnetic and diamagnetic gas components does not change.

[0031] Figure 4(B) shows the direction of gas travel through the coil 11 when the control signal is SIG2. When the control signal is SIG2, the control unit 60 applies voltage or current to the coil 11. A magnetic field is generated in the coil 11 that changes the direction of travel of paramagnetic gas components toward the center of the coil 11 in the axial direction. Therefore, when the control signal is SIG2, the direction of travel of paramagnetic gas components changes toward the center of the coil 11 in the axial direction. Gas sensor 31 mainly detects paramagnetic gas components. For example, gas sensor 31 detects oxygen (O2) and nitric oxide (NO). The direction of travel of diamagnetic gas components changes toward both ends of the coil 11 in the axial direction. Compared to gas sensor 31, gas sensors 30 and 32 mainly detect diamagnetic gas components. For example, gas sensors 30 and 32 detect water vapor (H2O) and chlorine (Cl2).

[0032] Figure 4(C) shows the direction of gas travel through the coil 11 when the control signal is SIG3. When the control signal is SIG3, the control unit 60 applies a greater voltage or current to the coil 11 than when the control signal is SIG2. A stronger magnetic field is generated in the coil 11 than when the control signal is SIG2. Therefore, when the control signal is SIG3, the direction of travel of the paramagnetic gas component changes more significantly towards the center of the coil 11 in the axial direction compared to when the control signal is SIG2. Gas sensor 31 detects more paramagnetic gas component than when the control signal is SIG2. When the control signal is SIG3, the direction of travel of the diamagnetic gas component changes more significantly towards both ends of the coil 11 in the axial direction compared to when the control signal is SIG2. Compared to gas sensor 31, gas sensors 30 and 32 detect more diamagnetic gas component than when the control signal is SIG2.

[0033] Next, the acquisition unit 70 acquires the first measurement value output by the gas sensor 31 and the second measurement value output by the gas sensor 32 based on the synchronization signal. The output unit 80 outputs the control signal and the detected value acquired from the acquisition unit 70 in association with each other. The determination unit 90 determines the gas type based on the previously acquired relationship between the gas type, the detected value, and the control signal, and the detected value and control signal output by the output unit 80.

[0034] The determination unit 90 determines the type of gas based on the gas characteristic table and the first measurement value, second measurement value, and control signal acquired by the acquisition unit 70. Based on the pre-acquired relationship between the magnitude of the voltage or current indicated by the control signal and the measurement value, it is determined that the gas to be detected contains oxygen (O2), nitric oxide (NO), water vapor (H2O), and chlorine (Cl2).

[0035] [Summary of Embodiments] According to the gas measuring instrument 1, the gas measured by the gas sensor 30 passes through the magnetic field generated by the magnetic field generator 10. At this time, an attractive force due to the magnetic field acts in the direction of travel of paramagnetic gases. A repulsive force due to the magnetic field acts in the direction of travel of diamagnetic gases. Therefore, the gas measuring instrument 1 can control the direction of gas travel according to the magnetism of the gas, and thus can perform a gas component sieving function. Furthermore, since the magnetic field acts indirectly on the gas, the sieving function does not deteriorate even with continuous use. Therefore, this gas measuring instrument 1 can be used continuously for gas component sieving.

[0036] In the gas measuring device 1, the energized coil 11 generates a magnetic field. Therefore, by interrupting the energization, the gas measuring device 1 can switch between a state in which gas components are sieved and a state in which gas components are not sieved.

[0037] In the gas measuring instrument 1, the control unit 60 controls the power supply unit to apply a voltage or current of the magnitude determined by the control signal to the coil 11 at a timing determined by the synchronization signal, based on a control signal that determines the magnitude of the voltage or current and a synchronization signal. Then, the acquisition unit 70 acquires the detected value from the gas sensor at a timing determined by the synchronization signal. In this way, the gas measuring instrument 1 can output the detected value and the synchronization signal in association.

[0038] In the gas measuring instrument 1, the determination unit 90 determines the type of gas based on a previously acquired relationship and the detected value and control signal output by the output unit 80. As a result, the gas measuring instrument 1 can determine the type of gas in a mixed gas containing paramagnetic and diamagnetic gases.

[0039] In gas measuring instrument 1, gas types different from those detected by gas sensor 30 can be detected by gas sensors 31 and 32. Compared to gas measuring instruments equipped with gas sensors capable of detecting only one type of gas, gas measuring instrument 1 can improve the accuracy of gas detection.

[0040] In the gas measuring instrument 1, multiple gas sensors 30, 31, and 32 are arranged along the direction of the magnetic field of the magnetic field generating unit 10. For paramagnetic gases, an attractive force acts along the direction of the magnetic field in the direction of travel C1. For diamagnetic gases, a repulsive force acts along the direction of the magnetic field in the direction of travel C2. Therefore, in the gas measuring instrument 1, multiple types of gas components, filtered along the direction of the magnetic field, can be detected by the multiple gas sensors 30, 31, and 32.

[0041] [Differentiation] Although various exemplary embodiments have been described above, the invention is not limited to the above-described exemplary embodiments, and various omissions, substitutions, and modifications may be made.

[0042] As shown in Figure 5(A), the axial direction of the coil 11 may extend along a direction that connects the inside and outside of the gas chamber 41. In this case, the magnetic field generated from the coil 11 passes through the gas sensor 31 and region 41a. The gas sensor 31 primarily detects paramagnetic gases attracted to the coil 11.

[0043] As shown in Figure 5(B), the magnetic field generating unit 10 may be a permanent magnet 13. The permanent magnet 13 may have its north pole and south pole aligned along the direction that connects the inside and outside of the gas chamber 41. In this case, the magnetic field generated from the permanent magnet 13 passes through the gas sensor 31 and region 41a. The gas sensor 31 mainly detects paramagnetic gases attracted to the permanent magnet 13. The configuration in which the magnetic field generating unit 10 consists of a permanent magnet 13 generates a magnetic field without using electricity, so the gas component sieving function can be used continuously with a simple configuration.

[0044] The magnetic field generating unit 10 and the gas sensor 30 may be manufactured by combining them after being formed separately. The magnetic field generating unit 10 and the gas sensor 30 may also be manufactured as a single unit.

[0045] The signal generation unit 50 may be integrated with the control unit 60. The acquisition unit 70 may be integrated with the output unit 80. The output unit 80 may be integrated with the determination unit 90.

[0046] The gas measuring instrument 1 may be configured without including the base material 40 and the gas chamber 41. In this case, the gas measuring instrument 1 is configured so that the magnetic field generating unit 10 is in close contact with the gas sensor 30. The gas measuring instrument 1 may be equipped with M types of gas sensors (where M is an integer of 2 or more). If M is 3 or more, the M types of gas sensors may include sensors of the same type. In addition, the strength of the electrostatic force of the coil 11 may be controlled in N steps (where N is an integer of 2 or more). In this case, the gas measuring instrument 1 can measure gases in a maximum of M × N combinations.

[0047] The gas measuring instrument 1 may be configured without including the determination unit 90. In this case, the output unit 80 of the gas measuring instrument 1 outputs the measured value and the control signal to the outside. The relationship between the measured value and the control signal may be obtained in advance by simulation. In this case, the strength of the magnetic field generated from the magnetic field generating unit 10 and the force generated between the paramagnetic gas and the diamagnetic gas can be calculated. The relationship between the measured value and the control signal may be calibrated with known gases. In this case, the relationship between the control signal and the strength of the magnetic field generating unit 10, and the output characteristics of the gas sensor 30 are calibrated based on known gases. [Explanation of symbols]

[0048] 1...Gas measuring instrument, 2...Measurement unit, 3...Circuit unit, 10...Magnetic field generation unit, 11...Coil, 12...Power supply unit, 13...Permanent magnet, 30, 31, 32...Gas sensors, 40...Base material, 41...Gas chamber, 41a, 41b...Region, 50...Signal generation unit, 60...Control unit, 70...Acquisition unit, 80...Output unit, 90...Determination unit.

Claims

1. A magnetic field generating unit that generates a magnetic field, A gas sensor that detects gas that has passed through the magnetic field generated from the magnetic field generating unit, A base material formed of a material that does not allow gas to pass through, having an opening at its top that communicates with the internal space, Power supply unit, Equipped with, The magnetic field generating unit is a coil arranged to cover the opening, The coil and the substrate define a gas chamber, The gas sensor is installed in the gas chamber, The axial direction of the coil extends along a direction perpendicular to the direction that connects the inside and outside of the gas chamber, The power supply unit energizes the coil, Gas measuring instrument.

2. A signal generation unit that outputs a synchronization signal to determine the timing, A control unit controls the power supply unit to apply a voltage or current of a magnitude determined by the control signal to the coil at a timing determined by the synchronization signal, based on a control signal that determines the magnitude of the voltage or current and the synchronization signal. An acquisition unit that acquires the detected value of the gas sensor at a timing determined by the synchronization signal, An output unit that outputs the detected value and the control signal in association, A gas measuring instrument according to claim 1, comprising the features described above.

3. The system further includes a determination unit that determines the type of gas based on a previously acquired relationship, the detected value, and the control signal. The aforementioned previously acquired relationship is the relationship between the gas type, the detected value, and the control signal. The gas measuring instrument according to claim 2.

4. The system further comprises a plurality of gas sensors, including the aforementioned gas sensor, The plurality of gas sensors include another gas sensor capable of detecting a gas type different from the gas type detected by the gas sensor. A gas measuring instrument according to any one of claims 1 to 3.

5. The plurality of gas sensors are each arranged along the direction of the magnetic field generated from the magnetic field generating unit. The gas measuring instrument according to claim 4.

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