Gas detection device having a housing with a connection channel

Abstract

Provided is a gas detection device including: a housing including an open portion that introduces a sensed gas into an internal space; a sensor portion disposed in the internal space of the housing; and a connection passage that connects a first opening and a second opening formed in the housing in a manner that opens toward the internal space of the housing. According to the present invention, a gas detection device that can measure a gas concentration with a fast response speed and high accuracy even when the pressure of the internal space of the housing in which the sensor portion is disposed increases can be provided.

Description

TECHNICAL FIELD

[0001] This application claims priority to Korean Patent Application No. 2020-0056689 filed on May 12, 2020, and includes all of the disclosure of the Korean Patent Application as part of the present specification.

[0002] The present application relates to a gas detection device, and more particularly, to a gas detection device in which a connection passage is formed in a housing. BACKGROUND

[0003] There are cases in which a method of measuring the concentration of a dissolved gas dissolved in a liquid is used in order to detect the characteristics or a change in the characteristics of the liquid. For example, for oil such as automobile engine oil, insulating oil of a transformer, or the like, which is used in various mechanical devices, as deterioration progresses, a change in the concentration of a dissolved gas such as an increase in hydrogen gas or carbon monoxide, acetylene gas, or the like occurs, and thus, if the concentration of such a dissolved gas is measured, it is possible to detect whether or not the oil is deteriorated. In fact, it is reported that there is a risk of explosion if the dissolved hydrogen gas of the insulating oil of a transformer is 1000 ppm or more. In addition, in the field of nuclear power, it is possible to know the corrosion of a pipe or power generation information by measuring the concentration of oxygen or heavy hydrogen gas, or the like, dissolved in water, and in the field of the metal industry, it is possible to constantly maintain the quality of the metal produced by measuring the concentration of a dissolved gas in molten metal.

[0004] In order to measure the concentration of a dissolved gas, a method of collecting a sample of a liquid, extracting a dissolved gas therefrom, and then analyzing it using gas chromatography is generally used. However, this method has a limitation in that it is not possible to measure the concentration of a dissolved gas in real time at an industrial site.

[0005] In Korean Patent No. 1512189, a technology of inserting a hydrogen sensor element having a sensor portion using a solid electrolyte into oil to detect the concentration of dissolved hydrogen gas is proposed. Although this technology has an advantage in that it is possible to measure the concentration of a dissolved gas in real time and simply, there is a problem in that the sensing electrode of the sensor portion is directly exposed to the liquid and thus easily deteriorated.

[0006] In Korean Patent Laid-Open No. 2016-0011722, a technology of inserting a hydrogen sensor element having a sensor portion disposed in a sealed space formed by a housing and a gas separation membrane into a liquid to measure the concentration of dissolved hydrogen gas permeated into the sealed space through the gas separation membrane while the sensing electrode of the sensor portion is not directly exposed to the liquid is proposed. This technology has an advantage in that it is possible to inhibit the deterioration of the sensing electrode of the sensor portion while measuring the concentration of a dissolved gas in real time and simply.

[0007] However, when the sensing electrode of the sensor portion is disposed in the closed space, the dissolved gas can be difficult to move to the sensing electrode of the sensor portion due to the pressure in the closed space, and the evaporation of the dissolved gas into the closed space. In particular, the gas sensor generally operates in a state of being heated to a high temperature using a heater, and thus the internal pressure of the closed space in which the sensing electrode of the sensor portion is disposed is further increased. Thus, it can be more difficult to move the dissolved gas evaporated from the liquid to the position of the sensing electrode of the sensor portion, which can be an obstacle to rapidly and accurately measuring the concentration of the dissolved gas.

[0008] To solve such a problem, a scheme can be considered in which the internal space of the housing in which the sensing electrode of the sensor portion is disposed is connected to the outside air, so that the pressure does not increase above the atmospheric pressure even when the sensor portion is heated to a high temperature. However, in this case, the dissolved gas evaporated from the liquid leaks to the outside air, and thus there is a problem in that the gas concentration of the internal space in which the sensing electrode of the sensor portion is disposed cannot be considered to accurately represent the concentration of the dissolved gas in the liquid. SUMMARY

[0009] The present application is to solve the above-described problems, and aims to provide a gas detection device capable of measuring the concentration of a gas with a fast response speed and high accuracy even when the pressure of the internal space of the housing in which the sensor portion is disposed is increased.

[0010] The object of the present application is not limited to the foregoing, and other objects and advantages of the present application not mentioned above can be understood through the following description.

[0011] The gas detection device according to an embodiment of the present application for achieving the above object can be characterized by including a housing including an open portion through which a sensing target gas is introduced into an internal space, a sensor portion disposed in the internal space of the housing, and a connection passage connected to a first opening and a second opening formed in the housing in a manner of being open to the internal space of the housing, and can further include a heater portion for heating the sensor portion to a sensing temperature.

[0012] The internal space of the housing can be connected to the outside air only through the open portion.

[0013] The internal space of the housing can be configured by a first internal space between the sensor portion and the open portion and a second internal space other than the first internal space, and the first opening can be open to the first internal space and the second opening can be open to the second internal space.

[0014] The housing can be a hollow tubular shape having the open portion formed at one end in the length direction, the sensor portion can be disposed in the internal space of the housing in a state in which one end in the length direction of a frame having an outer diameter smaller than an inner diameter of the housing is fixed, the other end in the length direction of the frame can be fixed in the housing to be gas-tight, and a space between the inner wall of the housing and the frame can form the second internal space, forming a circulation path that circulates the first internal space, the first opening, the connection passage, the second opening, and the second internal space.

[0015] In addition, the housing can be a hollow tubular shape having the open portion formed at one end in the length direction, the other end in the length direction of the housing can be plugged by a cover portion, and the sensor portion can be disposed in the internal space of the housing in a state in which the sensor portion is coupled to the inner wall of the housing. In this case, a gap can exist between the inner wall of the housing and the sensor portion, thereby forming a circulation path that circulates the first internal space, the first opening, the connection passage, the second opening, and the second internal space.

[0016] The sensor portion can include a hydrogen sensor element including a solid electrolyte, a sensing electrode formed on one surface of the solid electrolyte in the direction of the open portion, and a reference electrode formed on the other surface of the solid electrolyte, and the first opening can be located between the sensing electrode and the open portion.

[0017] A gas detection device according to an embodiment of the present disclosure can include a housing that is a hollow tubular shape including an internal space and having an open portion formed at a lower end in the length direction to be open toward the internal space to introduce a sensing target gas, a sensor portion disposed in the internal space at a position spaced apart from both an upper end and the lower end in the length direction of the housing by a predetermined distance and formed to face the open portion, and a heater portion that heats the sensor portion to a sensing temperature, the internal space of the housing including a first internal space below and a second internal space above with reference to a sensing electrode of the sensor portion, a first opening formed to be open toward the first internal space and a second opening formed to be open toward the second internal space being formed in the housing, the gas detection device having a connection passage that connects the first opening and the second opening to form a circulation path in which the sensing target gas introduced through the open portion circulates along the first internal space, the first opening, the connection passage, the second opening, and the second internal space.

[0018] In this case, the sensor portion can be disposed in the internal space in a state in which a lower end of a hollow tubular frame having a diameter smaller than an inner diameter of the housing is fixed, an inside of the frame being exposed to outside air in a state in which the inside is separated from the internal space of the housing, the sensor portion further including: a reference electrode exposed to the outside air through the inside of the frame.

[0019] Alternatively, the sensor portion can be disposed in the internal space in a manner in which a partial area of an edge is coupled to an inner wall of the housing through a predetermined coupling portion, a gap being formed between the sensor portion and the inner wall of the housing in a portion in which the coupling portion is not formed, the first internal space and the second internal space being communicated through the gap.

[0020] According to the present application, a connection passage connecting openings formed in a housing in a manner in which the openings are respectively open to internal spaces above and below a sensor portion is provided, thereby having an effect in that a gas detection device capable of measuring a gas concentration with a fast response speed and a high accuracy even if a pressure of an internal space of a housing in which the sensor portion is disposed is increased can be provided.

[0021] However, effects of the present application are not limited to the above-mentioned, and other effects not mentioned can be clearly understood by a person having ordinary knowledge in the technical field to which the present application pertains through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a schematic cross-sectional view of a gas detection device according to a first embodiment of the present application.

[0023] Figure 2 is a schematic cross-sectional view of a gas detection device according to a second embodiment of the present application.

[0024] Figure 3 is Figure 2 an A-A line cross-sectional view of

[0025] Figures 4 to 6 is a view for explaining a hydrogen sensor element that can be used as a sensor portion in the present application.

[0026] Figure 7 and Figure 8 is a use example of a gas detection device according to an embodiment of the present application.

[0027] Figure 9 is a result of measuring a gas concentration using a gas detection device according to an embodiment of the present application.

[0028] Figure 10 is a result of measuring a gas concentration using a gas detection device according to a comparative example of the present application. DETAILED DESCRIPTION

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to or restricted to these embodiments. In describing the embodiments of the present invention, the same names and reference numerals are used for corresponding constituent elements. In describing the present invention, detailed descriptions of related well-known technologies are omitted where it is determined that such detailed descriptions would unnecessarily obscure the spirit of the present invention. Furthermore, unless otherwise defined, the terminology used in this specification should be interpreted as commonly understood by one of ordinary skill in the art.

[0030] Figure 1 This is a schematic cross-sectional view of a gas detection device according to a first embodiment of the present invention. (Refer to...) Figure 1 As described above, the gas detection device 1A according to the first embodiment of the present invention includes: a housing 10 having an opening 70 formed on one side; a sensor 20 disposed within the housing 10; a heater 50 for heating the sensor 20 to a sensing temperature; and a connection passage 60 connecting the first opening 61 and the second opening 62 formed in the housing 10.

[0031] The housing 10 can be provided as a hollow tube. It can be located on one side of the housing 10. Figure 1 An opening 70 is formed on the lower side of the housing 10, providing an inlet and outlet for introducing the gas to be sensed. When the gas detection device 1A is used to measure the gas concentration in the measurement environment, the housing 10 can be configured such that the opening 70 communicates with the measurement environment. For example, when the gas detection device 1A is used to measure the concentration of dissolved gas in a liquid, the housing 10 of the gas detection device 1A can be configured such that the opening 70 communicates with the liquid storage container or that one end with the opening 70 is immersed in the liquid. Dissolved gas evaporating from the liquid fills the internal space 30 of the housing 10, and the sensor unit 20 can sense it.

[0032] The sensor unit 20 can be disposed within the housing 10 and disposed along the length direction of the housing 10. Figure 1 The positions separated from both ends in the vertical direction. For example, as... Figure 1 As shown, the sensor section 20 can be positioned at a length distance d1 from one end of the housing 10 on the opening 70 side and at a length distance d2 from the other end of the housing 10. Here, the position of the sensor section 20 can be the position of the sensing electrode formed in the sensor section 20.

[0033] Thus, in order to position the sensor unit 20 at a location spaced apart in the longitudinal direction from the end of the housing 10, the sensor unit 20 can be fixed to one end of a frame 22 of a predetermined length. Figure 1The frame 22 is positioned within the housing 10 in a state where it is located on the lower side. The frame 22 can be formed from a tube with a diameter smaller than that of the housing 10, such that there is a gap in the width direction between the inner wall of the housing 10 and the frame 22. Figure 1 A gap g is formed in the left-right direction. The sensor part 20 may be fixed to one end of the frame 22, and the other end of the frame 22 may be attached to the housing 10. When the sensor part 20 is made into a tubular shape, the frame 22 may be a structure included within the sensor part 20. The connection between the frame 22 and the housing 10 can be achieved using various methods such as adhesive bonding, threaded bonding, or brazing, and is not limited to any particular method. Alternatively, the connection between the frame 22 and the housing 10 can be a gas-tight connection. For this purpose, a sealing material 21 may be included at the connection point between the frame 22 and the housing 10. The sealing material 21 may be formed from an elastic polymer material such as an O-ring. Alternatively, when the frame 22 and the housing 10 are bonded together, the sealing material 21 may be an adhesive material.

[0034] By combining the housing 10 and the frame 22 into a gas-tight seal, the internal space 30 of the housing 10 can form a sealed space cut off from the outside air if the opening 70 is removed. Alternatively, even if the combination of the frame 22 and the housing 10 is not a gas-tight combination, it can be achieved by blocking the other side of the housing 10 where the opening 70 is not formed. Figure 1 The structure of the upper part of the interior space 30 forms a closed space.

[0035] The internal space 30 of the housing 10 can be divided into a first internal space 31 and a second internal space 32 by the position of the sensor unit 20. Specifically, the first internal space 31 can be the space between the sensor unit 20 and the opening 70 within the internal space 30 of the housing 10, and the second internal space 32 can be the space within the internal space 30 of the housing 10 excluding the first internal space 31. Figure 1 In one embodiment, the first internal space 31 may be the lower internal space of the sensor unit 20, and the second internal space 32 may be the upper internal space of the sensor unit 20, i.e., the space formed by the gap g between the frame 22 and the inner wall of the housing 10. Here, the upper and lower sides of the sensor unit 20 may be divided based on the position of the sensing electrodes formed on the sensor unit 20.

[0036] The heater section 50 is a structure used to heat the sensor section 20 to the sensing temperature. The sensing temperature varies depending on the type of sensor and can be 300°C or higher. Figure 1The heater section 50 can be configured by, for example, a resistance heating type heating coil wound outside the case 10 at a position where the sensor section 20 is disposed, but can be provided in various forms other than this. For example, the heater section 50 can be disposed inside the case 10, and can be provided in the form of a heating pattern printed on a predetermined substrate instead of a heating coil. Alternatively, the heater section 50 can be provided by a heating coil wound around the frame 22, or can be provided in the form of being built into the frame 22 or the sensor section 20. The heater section 50 is not limited to a resistance heating type, and can be provided by a light irradiation type heater section such as a heating lamp or an LED.

[0037] When the gas detection device 1A is used in a high-temperature environment without heating the sensor section 20, the heater section 50 can be omitted. For example, when used for measuring the concentration of a dissolved gas in a molten metal at a high temperature, the gas detection device 1A can not include the heater section 50.

[0038] When the gas detection device 1A is connected to a measurement environment at high pressure, or when the opening portion 70 is connected to a liquid storage container for measuring a dissolved gas in a liquid, the internal space 30 can become a space at high pressure. In particular, if the sensor section 20 is heated to a high temperature by the heater section 50, the pressure of the internal space 30 can further increase with the temperature. Such an increase in pressure can make it difficult for the target gas to move to the sensor section 20.

[0039] To address such a problem, the gas detection device 1A according to the first embodiment of the present application is provided with the connection passage 60. Specifically, the first opening 61 and the second opening 62 are formed in the case 10, and the first opening 61 and the second opening 62 are connected by the connection passage 60. The first opening 61 and the second opening 62 can be formed in the case 10 in such a manner that the first opening 61 is open toward the first internal space 31 and the second opening 62 is open toward the second internal space 32. The first opening 61 and the second opening 62 can be formed in the case 10 in such a manner that the first opening 61 is open toward the first internal space 31 and the second opening 62 is open toward the second internal space 32. Figure 1 For reference, the first opening 61 can be formed on the lower side than the sensor section 20, and the second opening 62 can be formed on the upper side than the sensor section 20. Here, the upper side and the lower side of the sensor section 20 can be divided based on the position of the sensing electrode formed in the sensor section 20.

[0040] According to such a configuration, a circulation path in which the gas in the first internal space 31 passes through the first opening 61, the connection passage 60, the second opening 62, and the second internal space 32 again to re-enter the first internal space 31 can be formed. By forming such a circulation path, even in a case where the vicinity of the sensor section 20 is at high pressure, the target gas introduced into the internal space 30 through the opening portion 70 can more easily move to the sensor section 20 side.

[0041] Figure 2is a schematic cross-sectional view of a gas detection device according to a second embodiment of the present application. Referring to Figure 2 Exemplary description will be made that the gas detection device 1B according to the second embodiment of the present application is different from the gas detection device 1A according to the first embodiment in that the sensor portion 20 is disposed in the housing 10 without using a frame.

[0042] The gas detection device 1B according to the second embodiment of the present application includes: the housing 10 in which an open portion 70 is formed on one side; the sensor portion 20 disposed in the housing 10; the heater portion 50 for heating the sensor portion 20 to a sensing temperature; and the connection passage 60 connected to the first opening 61 and the second opening 62 formed in the housing 10.

[0043] The housing 10 can be provided as a hollow pipe shape open on one side (lower side of Figure 2 ). It can be a configuration in which the open portion 70 is formed on the open side and the other side (upper side of Figure 2 ) is plugged by the cover portion 12. Thereby, the internal space 30 of the housing 10, if the open portion 70 is removed, can form a closed space cut off from the outside air.

[0044] The sensor portion 20 can be disposed in the internal space 30 of the housing 10 and disposed at a position separated from both end portions in the length direction (up and down direction of Figure 2 ) of the housing 10. The sensor portion 20 can be bonded to the internal space 30 of the housing 10 by a bonding portion 23. The bonding portion 23 can be an adhesive substance, but is not limited thereto, and various bonding methods capable of disposing the sensor portion 20 in the internal space 30 of the housing 10 can be used.

[0045] The internal space 30 of the housing 10 can be divided into a first internal space 31 and a second internal space 32 by the position where the sensor portion 20 is disposed. It can be that the first internal space 31 is a space between the sensor portion 20 and the open portion 70 in the internal space 30 of the housing 10, and the second internal space 32 is a space other than the first internal space 31 in the internal space 30 of the housing 10. In Figure 2 the embodiment, it can be that the first internal space 31 is a lower internal space of the sensor portion 20, and the second internal space 32 is an upper internal space of the sensor portion 20, that is, a space between the cover portion 12 and the sensor portion 20. Here, the upper side and the lower side of the sensor portion 20 can be divided based on the position of the sensing electrode formed in the sensor portion 20.

[0046] The heater portion 50 is a structure for heating the sensor portion 20 to a sensing temperature, and as Figure 2As illustrated in the middle example, the heater portion 50 can be configured with a resistance heating type heating coil wound outside the housing 10 in which the sensor portion 20 is disposed, but can be provided in various forms without being limited thereto. For example, the heater portion 50 can be disposed inside the housing 10, and can be provided in the form of a heating pattern printed on a predetermined substrate instead of the heating coil. Alternatively, the heater portion 50 can be provided in the form of being built in the sensor portion 20. The heater portion 50 is not limited to the resistance heating type, and can be provided with a light irradiation type heater portion such as a heating lamp or an LED.

[0047] When the gas detection device IB is used in a high-temperature environment without heating the sensor portion 20, the heater portion 50 can be omitted. For example, when used for measuring the dissolved gas concentration in a molten metal at a high temperature, the gas detection device IB can not include the heater portion 50.

[0048] The housing 10 is formed with a first opening 61 and a second opening 62, and the first opening 61 and the second opening 62 are connected by the connection passage 60. The first opening 61 and the second opening 62 can be formed in the housing 10 in such a manner that the first opening 61 is open toward the first internal space 31 and the second opening 62 is open toward the second internal space 32. Figure 2 For reference, the first opening 61 can be formed on the lower side than the sensor portion 20, and the second opening 62 can be formed on the upper side than the sensor portion 20. Here, the upper side and the lower side of the sensor portion 20 can be divided based on the position of the sensing electrode formed in the sensor portion 20.

[0049] Although the sensor portion 20 is coupled to the housing 10 by the coupling portion 23, the first internal space 31 and the second internal space 32 can not be completely cut off by the coupling portion 23 and the sensor portion 20. For example, the coupling portion 23 can be provided in such a manner that only a part of the edge of the sensor portion 20 is coupled to the inner wall of the housing 10, so that a gap g is formed between the inner wall of the housing 10 and the sensor portion 20. Figure 3 As a diagram for explaining this, it is a cross-sectional view of the A-A line of Figure 2 . Referring to Figure 3 The coupling portion 23 can be formed only at four places in the edge of the sensor portion 20, and a predetermined gap g can be formed between the sensor portion 20 and the inner wall of the housing 10 at a portion where the coupling portion 23 is not formed. Thereby, the movement of gas between the first internal space 31 and the second internal space 32 can be facilitated. In addition to the coupling structure as Figure 3 The coupling portion 23 can be formed of a gas permeable material or a through hole (not shown) can be formed in the sensor portion 20 to communicate the first internal space 31 and the second internal space 32, in addition to the coupling structure as

[0050] With this configuration, a circulation path can be formed whereby the gas in the first internal space 31 passes through the first opening 61, the connecting passage 60, the second opening 62, and the second internal space 32, and then re-enters the first internal space 31. By forming such a circulation path, even when the area near the sensor unit 20 is under high pressure, the gas being sensed, introduced into the internal space 30 through the opening 70, can more easily move to the sensor unit 20 side.

[0051] According to embodiments of the present invention, the sensor unit 20 for gas detection devices 1A and 1B can use various gas sensor elements depending on the target gas, applicable application, etc. Depending on the target gas, hydrogen sensor elements, carbon monoxide sensor elements, hydrocarbon sensor elements, etc., can be used as the sensor unit 20. Furthermore, depending on its shape, sensor elements of various forms, such as pellet, chip, and tube, can be used as the sensor unit 20. Additionally, depending on the gas detection principle, electrochemical type sensor elements that measure changes in electromotive force (EMF) based on gas concentration using a solid electrolyte, and semiconductor type sensor elements that utilize semiconductor materials whose resistance changes according to gas concentration, can be used as the sensor unit 20.

[0052] Figures 4 to 6 This is a diagram illustrating a hydrogen sensor element that can be used as the sensor section 20 in this invention.

[0053] Figure 4 The sensor section 20A is particularly suitable for use in the first embodiment of the present invention. Figure 1 The hydrogen sensor element of the hydrogen detection device. (Refer to...) Figure 4 As can be described, the sensor unit 20A may include: a solid electrolyte with a dual-bonded structure of an oxygen ion conductor 211 and a hydrogen ion conductor 212; a reference electrode 213 formed on the surface of the oxygen ion conductor 211; and a sensing electrode 214 formed on the surface of the hydrogen ion conductor 212.

[0054] The oxygen ion conductor 211 can use stabilized zirconia made by adding various substances to zirconia (ZrO2), such as YSZ (Yttria stabilized zirconia), CSZ (calcium stabilized zirconia), MSZ (Magnesium stabilized zirconia), and the like, solid electrolytes, or CeO2-based compounds added with Gd2O3or the like. The hydrogen ion conductor 212 can use a substance in which various substances are substituted for the B site of a substance having a perovskite structure with ABO3form, such as CaZr 0.9 In 0.1 O 3-x CaZrO3-based, SrZr 0.95 Y 0.05 O 3-x SrZrO3-based, SrCe 0.95 Yb 0.05 O 3-x SrCeO3-based, BaCe 0.9 Nd 0.1 O 3-x BaCeO3-based, BaTiO3, SrTiO3, PbTiO3, and the like, Ti-based compounds.

[0055] In addition, the reference electrode 213 and the sensing electrode 214 can be formed of a noble metal such as platinum (Pt).

[0056] The reference electrode 213 and the sensing electrode 214 are electrically connected to the measurement unit 90 through a lead, and the hydrogen gas concentration can be measured by measuring the electromotive force. The electromotive force E measured between the reference electrode 213 and the sensing electrode 214 and the oxygen partial pressure (P O2 ) on the reference electrode 213 side and the hydrogen partial pressure (P H2 ) on the sensing electrode 214 side satisfy the following relationship.

[0057] E = Eo + A • log P H2 + (A / 2) • log P O2 -------- (1)

[0058] In the above equation, Eo and A are constants that depend only on the temperature, and therefore if the oxygen partial pressure (P O2 ) on the reference electrode 213 side is known, the hydrogen partial pressure (P H2 ) on the sensing electrode 214 side can be determined from the measured electromotive force E.

[0059] The oxygen partial pressure (P O2 ) on the reference electrode 213 side can be fixed by exposing the reference electrode 213 to the atmosphere.O2 That is, refer to them together. Figure 1 and Figure 4 The gas detection device 1A is configured such that the frame 22 fixed to the sensor section 20A is gas-sealed by the sealing material 21 and the housing 10, while the reference electrode 213 is exposed to the atmosphere, thereby allowing the oxygen partial pressure (P) on the reference electrode 213 side to be detected. O2 The partial pressure of oxygen in the air is fixed at 0.21 ppm. Therefore, the partial pressure of hydrogen on the sensing electrode 214 side can be calculated according to formula (1) by measuring the electromotive force E between the reference electrode 213 and the sensing electrode 214. H2 ).

[0060] Figure 5 The sensor section 20B thermodynamically fixes the oxygen partial pressure (P) by covering the reference electrode 213 with a reference material 215. O2 This replaces exposing the reference electrode 213 to the atmosphere to fix the oxygen partial pressure (P). O2 The structure of ) is similar to this point. Figure 4 The sensor section 20A is different.

[0061] The reference material 215 for fixing the oxygen partial pressure can be a mixture of metals and metal oxides such as Cu / CuO, Ni / NiO, Ti / TiO2, Fe / FeO, Cr / Cr2O3, and Mo / MoO, or a mixture of metal oxides with different oxidation degrees such as Cu2O / CuO and FeO / Fe2O3. If such an oxygen partial pressure fixing reference material 215 is used to cover the reference electrode 213, the oxygen partial pressure on the reference electrode 213 side can be thermodynamically fixed. That is, the oxygen partial pressure on the reference electrode 213 side is determined by the oxygen partial pressure fixing reference material 215 rather than by external air, as shown in the reference... Figure 4 As explained, the electromotive force between the reference electrode 213 and the sensing electrode 214 can be measured, and the hydrogen partial pressure on the sensing electrode 214 side can be calculated according to formula (1).

[0062] Figure 5 The sensor unit 20B can also be adapted to either the gas detection device 1A according to the first embodiment of the present invention or the gas detection device 1B according to the second embodiment. To prevent the oxygen partial pressure fixing reference material 215 from being affected by external air or the gas environment within the internal space 30, a sealing cap 218 for cutting off the oxygen partial pressure fixing reference material 215 from external air can also be added. The sealing cap 218 can be formed of a dense ceramic material or the like that can prevent external air penetration; if the influence of external air is minimal, the sealing cap 218 can be omitted.

[0063] Figure 6The sensor portion 20C includes a hydrogen ion conductor 212, a reference electrode 213 and a sensing electrode 214 formed on both sides of the hydrogen ion conductor 212, and a hydrogen partial pressure fixing reference substance 216 covering the reference electrode 213. That is, in place of the oxygen partial pressure fixing reference substance, the hydrogen partial pressure fixing reference substance 216 covers the reference electrode 213. Figure 5 The sensor portion 20B differs from the sensor portion 20C in that there is no oxygen ion conductor and the hydrogen partial pressure fixing reference substance 216 covers the reference electrode 213 in place of the oxygen partial pressure fixing reference substance.

[0064] The hydrogen partial pressure fixing reference substance 216 can use a mixed phase of a metal and a metal hydride such as Ti / TiH2, Zr / ZrH2, Ca / CaH2, Nd / NdH2, and the like, and for this purpose, the hydrogen partial pressure (P 2，H2 ) on the side of the reference electrode 213 can be fixed thermodynamically.

[0065] Figure 6 The sensor portion 20C can also measure the electromotive force E between the reference electrode 213 and the sensing electrode 214 and determine the hydrogen partial pressure (P 1，H2 ) on the side of the sensing electrode 214 according to the following Nernst equation.

[0066] E = -(RT / 2F) ln (P 2，H2 / P 1，H2 ) (2)

[0067] In the above equation (2), R is a gas constant, F is a Faraday constant, and T is a sensing temperature, all of which are constants, and the hydrogen partial pressure (P 2，H2 ) on the side of the reference electrode 213 is also a value determined by the hydrogen partial pressure fixing reference substance 216, so the hydrogen partial pressure (P P1，H2 ) on the side of the sensing electrode 214 is calculated from the measured electromotive force E value.

[0068] Figure 6 The sensor portion 20C can also be applied to either of the gas detecting device 1A according to the first embodiment of the present application and the gas detecting device 1B according to the second embodiment. In order to prevent the hydrogen partial pressure fixing reference substance 216 from being affected by the gas environment of the outside air or the inside space 30, a sealing cover 218 for cutting off the hydrogen partial pressure fixing reference substance 216 from the outside air can also be additionally provided.

[0069] The gas detecting device according to the embodiments of the present application can be used for measuring the dissolved gas concentration in a liquid.

[0070] Figure 7 This is an example of using the gas detecting device of the present application for measuring the dissolved gas concentration in a liquid contained in a liquid storage container 100. In this example, the gas detecting device 1A according to the first embodiment of the present application is used. Figure 7The gas detecting device 1 according to the present application is not limited to the above-described embodiments, and can be used in various applications. For example, the gas detecting device 1 according to the present application can be used in a gas detecting device 1A according to a first embodiment shown in FIG. 10 or a gas detecting device 1B according to a second embodiment shown in FIG. 11.

[0071] Referring to Figure 7 , the gas detecting device 1 according to the present application can be attached to the liquid storage container 100 through the port 110. As illustrated, the port 110 can be formed in the side surface of the liquid storage container 100, but is not limited thereto, and can be formed in various positions such as the upper surface or the lower surface of the liquid storage container 100. If the gas detecting device 1 is attached to the liquid storage container 100 through the port 110, the inside of the liquid storage container 100 and the internal space 30 of the gas detecting device 1 communicate with each other, and the dissolved gas in the liquid contained in the liquid storage container 100 can evaporate and move to the internal space 30.

[0072] Generally, the solubility of a gas to a liquid follows the Sievert's rule of formula (3).

[0073] C = k - P gas ---- (3)

[0074] C is the concentration of the dissolved gas dissolved in the liquid, k is a constant depending on the kind of gas, temperature, etc., and P gas is the partial pressure of the gas in the space in contact with the liquid. That is, the dissolved gas concentration (C) and the partial pressure of the gas in the space in contact with the liquid (P gas ) are proportional, and the equilibrium state is reached when the evaporation speed of the gas evaporated from the liquid into the space and the speed of the gas in the space dissolved in the liquid are the same.

[0075] According to such a principle, if the gas detecting device 1 according to the present application is connected to the liquid storage container 100 as Figure 7 , the dissolved gas in the liquid contained in the liquid storage container 100 evaporates into the internal space 30 of the gas detecting device 1 and forms an equilibrium. Therefore, the dissolved gas concentration in the liquid can be known by measuring the gas concentration (partial pressure of the gas) in the internal space 30 using the sensor portion 20.

[0076] On the other hand, as the pressure of the liquid in the liquid storage container 100 increases, the internal pressure of the internal space 30 of the gas detecting device 1 connected to the liquid storage container 100 can increase. That is, the liquid contained in the liquid storage container 100 moves to the internal space 30 of the gas detecting device 1 through the port 110 and a liquid surface 120 can be formed in the internal space 30 of the gas detecting device 1. Thus, the volume of the gas in the internal space 30 of the gas detecting device 1 can shrink until the internal pressure of the internal space 30 is the same as the pressure of the liquid.

[0077] An increase in the internal pressure of such an internal space 30 can make it difficult for gas evaporated from the liquid to move to the sensing electrode 214 of the sensor portion 20. In particular, since the sensor portion 20 is heated to a sensing temperature by the heater portion 50, the internal pressure of the internal space 30 is further increased, thereby making it more difficult for the dissolved gas to move to the sensing electrode 214. This can become an obstacle to rapidly and accurately measuring the concentration of the dissolved gas.

[0078] However, the gas detection device 1 according to the present application is such that the gas in the internal space 30 can circulate along the connection passage 60 that connects the first opening 61 and the second opening 62 that are respectively open toward the first internal space 31 and the second internal space 32, and thus even in the case where the internal space 30 is in a high-pressure state, the gas introduced through the opening portion 70 can smoothly move to the sensing electrode 214. Thus, the concentration of the dissolved gas can be rapidly and accurately measured.

[0079] In Figure 7 In the above, it is preferable that the liquid surface 120 be formed lower than the first opening 61, but it can also be formed higher than the first opening 61. That is, even if the first opening 61 is immersed in the liquid, the dissolved gas evaporated from the liquid can move to the second opening 62 side through the connection passage 60. However, the liquid surface 120 should be formed lower than the sensor portion 20, and thus it is preferable that the length of the housing 10 and / or the height of the port 110 be designed in consideration of the use environment such as the liquid pressure. Alternatively, in order to prevent the sensor portion 20 from being contaminated by the liquid, a gas-permeable filter can be provided at the port 110 or the first internal space 31. The gas-permeable filter is not limited in material and form as long as it is a structure through which only gas can pass but liquid cannot pass, and for example, can be a gas-permeable film made of graphite, ceramic powder, PTFE film, or the like.

[0080] Figure 8 Another use example of the gas detection device according to the present application is to measure the concentration of the dissolved gas in the liquid contained in a liquid storage container 300. The liquid storage container 300 can be a transformer, and the liquid contained in the liquid storage container 300 can be transformer oil.

[0081] Reference will be made to Figure 8 be described below, a circulation pipe 310 for circulating the liquid is connected to the liquid storage container 300. The circulation pipe 310 is provided with valves 313, 314 and a circulation motor 320, and the circulation motor 320 is driven in a state where the valves 313, 314 are open, thereby forming a circulation path in which the liquid circulates in the direction indicated by the arrow in the drawing.

[0082] The measurement tank 330 is provided on the circulation path, and is configured so that the liquid circulating along the circulation pipe 310 passes through the measurement tank 330. That is, the liquid circulating can be temporarily stored in the measurement tank 330.

[0083] The gas detection device 1 according to the present application can be combined with the measurement tank 330 through the port 340. Thereby, the dissolved gas evaporated from the liquid in the measurement tank 330 can move to the internal space 30 of the gas detection device 1. In order to prevent the liquid from moving to the gas detection device 1, a gas permeable filter 341 can be provided at the port 340. The gas detection device 1 is usable for both the gas detection device 1A according to the first embodiment of the present application and the gas detection device 1B according to the second embodiment.

[0084] Figure 9 is a result of measuring the electromotive force E of the sensor section 20 after connecting the gas detection device 1A according to the first embodiment of the present application to a measurement environment in which the hydrogen concentration is constantly maintained at 4%. At this time, the sensor section 20 used a hydrogen sensor element of Figure 4 . That is, the sensor section 20 used an electrochemical hydrogen sensor in which an oxygen ion conductor 211 and a hydrogen ion conductor 212 are joined, a reference electrode 213 is formed in the oxygen ion conductor 211, and a sensing electrode 214 is formed in the hydrogen ion conductor 212. The oxygen ion conductor 211 and the hydrogen ion conductor 212 respectively used YSZ (Yttria stabilized zirconia) and CaZr 0.9 In 0.1 O 3-x , the reference electrode 213 and the sensing electrode 214 were formed of platinum (Pt).

[0085] The sensor section 20 was heated using the heater section 50 while connecting a thermocouple to the sensor section 20 to measure the temperature, and the change in the temperature and the electromotive force was measured over time. As Figure 9 confirmed in , the electromotive force continued to rise as the temperature rose, and a stable electromotive force of about 1.1 V was measured at a temperature of about 300°C or higher.

[0086] Figure 10 is a result measured under the same conditions using a gas detection device in which the connection passage 60 was not formed for comparison. The gas detection device used in Figure 10 is the same as the gas detection device used in Figure 9 except for the fact that the connection passage 60 and the first and second openings 61 and 62 were not formed. Referring to Figure 10 , it can be confirmed that, although there was a tendency for the electromotive force to increase as the temperature rose, the electromotive force value was very low and was measured to be unstable compared to the result of Figure 9 .

[0087] From the above results, it is known that when the gas detecting device of the present application is used, the gas concentration can be measured rapidly and accurately.

[0088] The above has been described with reference to limited embodiments and drawings, but it will be apparent to a person of ordinary skill in the art that various modifications can be made within the scope of the technical concept of the present application. For example, a plurality of connection passages can be provided in the gas detecting device of the present application. Therefore, the scope of protection of the present application should be determined according to the recitations of the claims and their equivalent ranges.

Claims

1. A gas detection device, characterized by, including: a housing including an open portion through which a sensing target gas is introduced into an internal space; a sensor portion disposed in the internal space of the housing; and a connection passage connecting a first opening and a second opening formed in the housing in a manner open to the internal space of the housing, the internal space of the housing is composed of a first internal space between the sensor portion and the open portion and a second internal space other than the first internal space, the first opening is open to the first internal space and the second opening is open to the second internal space, the housing is hollow and tubular with the open portion formed at one end in the length direction, the sensor portion is disposed in the internal space of the housing in a state fixed at one end in the length direction of a frame having an outer diameter smaller than an inner diameter of the housing, the other end in the length direction of the frame is fixed to the housing in a gas-tight manner.

2. The gas detection device according to claim 1, wherein a space between an inner wall of the housing and the frame forms the second internal space, a circulation path is formed that circulates the first internal space, the first opening, the connection passage, the second opening, and the second internal space.

3. The gas detection device according to claim 1, wherein the sensor portion includes: a solid electrolyte; a sensing electrode formed on one face of the solid electrolyte in the direction of the open portion; and a reference electrode formed on the other face of the solid electrolyte, the frame is formed in a hollow and tubular shape, an inside of the frame is exposed to outside air in a state separated from the internal space of the housing, the reference electrode is exposed to outside air through the inside of the frame. including:

4. A gas detection device, characterized by a housing including an open portion through which a sensing target gas is introduced into an internal space; a sensor portion disposed in the internal space of the housing; and a connection passage connecting a first opening and a second opening formed in the housing in a manner open to the internal space of the housing, the internal space of the housing is composed of a first internal space between the sensor portion and the open portion and a second internal space other than the first internal space, the first opening is open to the first internal space and the second opening is open to the second internal space, the housing is hollow and tubular with the open portion formed at one end in the length direction, the other end in the length direction of the housing is plugged by a cover portion, the sensor portion is disposed in the internal space of the housing in a state bonded to an inner wall of the housing.

5. The gas detection device according to claim 4, wherein a gap exists between the inner wall of the housing and the sensor portion, a circulation path is formed that circulates the first internal space, the first opening, the connection passage, the second opening, and the second internal space.

6. The gas detection device according to claim 1 or 4, further comprising: a heater portion for heating the sensor portion to a sensing temperature.

7. The gas detection device according to claim 1 or 4, wherein ​ ​ ​ An interior space of the housing is communicated with outside air only through the opening.

8. The gas detection device according to claim 1 or 4, wherein The sensor portion includes a hydrogen sensor element.

9. The gas detection device according to claim 8, wherein The hydrogen sensor element includes: a solid electrolyte; a sensing electrode formed on one side of the solid electrolyte in the direction of the opening; and a reference electrode formed on the other side of the solid electrolyte, The first opening is located between the sensing electrode and the opening.

10. The gas detection device according to claim 4, wherein a marginal portion is joined to an inner wall of the housing by a predetermined joining portion, a gap is formed between the sensor portion and the inner wall of the housing in a portion where the joining portion is not formed, and the first interior space and the second interior space are communicated through the gap.

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