Odor detection device and odor detection method

Abstract

[Problem] To provide an odor detection device and an odor detection method that provide a high cleaning effect with a simple structure. [Solution] An odor detection device according to the present invention is equipped with a sensor chamber, a flow channel, a first gas delivery part, and a second gas delivery part. The sensor chamber accommodates therein a sensor element, and has a first intake port, a first discharge port disposed at a position opposite to the first intake port with the sensor element therebetween, a second intake port, and a second discharge port disposed at a position opposite to the second intake port with the sensor element therebetween. The flow channel has a filter thereinside, is connected to the second discharge port, and is connected to the second intake port. The first gas delivery part causes gas to flow into the sensor chamber through the first intake port, and then to be discharged from the first discharge port. The second gas delivery part causes gas to flow from the sensor chamber into the flow channel through the second discharge port, and causes the gas to flow from the flow channel into the sensor chamber through the second intake port.

Description

[Technical field]

[0001] The present invention relates to an odor detection device and an odor detection method for detecting odor components in a gas. [Background technology]

[0002] An odor sensor has a sensitive membrane that adsorbs odor components in a gas. The sensitive membrane is vibrated at a predetermined frequency, and the odor components can be detected by observing the frequency change caused by the adsorption of the odor components. With such an odor sensor, after measuring an odor component, it is necessary to clean the sensitive membrane to remove the odor components adsorbed on the sensitive membrane before the next measurement.

[0003] For example, Patent Document 1 discloses a technique for switching flow paths using a valve to switch between sample gas and cleaning air. Patent Document 2 also discloses a technique capable of physically switching between the flow paths of a test fluid and a control fluid (cleaning gas). Patent Document 3 also discloses a technique for circulating clean gas during gas cleaning by switching the flow paths using the opening and closing of a valve. Patent Document 4 also discloses a technique for circulating clean gas (purge gas) during gas cleaning. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-170461 [Patent Document 2] JP 2019-120561 A [Patent Document 3] JP 2002-39939 A [Patent Document 4] JP 2016-90484 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the configuration described in Patent Document 1, the device is large-scale and valve switching is not easy. In addition, in the configuration described in Patent Document 2, the cleaning gas is required to have stable components, but air is not sufficiently stable, and if a standard gas is prepared separately, the device becomes large-scale. Furthermore, in the configuration described in Patent Document 3, control of the opening and closing of the valve is required, and a specific flow path structure is not disclosed. In addition, in the configuration described in Patent Document 4, a specific method of controlling the circulation of the green gas is not disclosed.

[0006] In view of the above circumstances, an object of the present invention is to provide an odor detection device and an odor detection method that are simple in structure and have a high cleaning effect. [Means for solving the problem]

[0007] In order to achieve the above object, an odor detection device according to one aspect of the present invention includes a sensor chamber, a flow path, a first gas delivery section, and a second gas delivery section. The sensor chamber houses a sensor element and has a first intake port, a first exhaust port provided on the opposite side of the sensor element from the first intake port, a second intake port, and a second exhaust port provided on the opposite side of the sensor element from the second intake port. The flow path has a filter therein, 2nd outlet Connected to the above 2nd intake port is connected to. The first gas delivery section causes gas to flow into the sensor chamber from the first inlet and exhausts the gas from the first outlet. The second gas delivery section causes gas to flow from the sensor chamber through the second outlet into the flow path, and causes gas to flow from the flow path into the sensor chamber through the second inlet.

[0008] The detection device is located above or below the sensor chamber. , so as to overlap with the sensor chamber when viewed from above. The flow path may be provided.

[0009] The above flow path is , in a plane perpendicular to the vertical direction It may have a serpentine shape.

[0010] The flow channel includes a first portion extending in a first direction and a second portion extending in a second direction. 1 It may have a second portion downstream of the first portion and extending in a second direction opposite to the first direction, and a third portion downstream of the second portion and extending in the first direction.

[0011] The sensor chamber may have a first chamber in which the first intake port and the second intake port are provided, a second chamber communicating with the first chamber and in which the first exhaust port and the second exhaust port are provided, and a throttle portion that restricts the flow of gas from the first chamber to the second chamber.

[0012] The detection device may further include a control unit that switches between a first state in which the first gas delivery unit is operated and the second gas delivery unit is stopped, and a second state in which the first gas delivery unit is stopped and the second gas delivery unit is operated.

[0013] In order to achieve the above object, an odor detection method according to one embodiment of the present invention includes a detection step and a cleaning step. The detection step includes driving the first gas delivery unit, stopping the second gas delivery unit, and causing gas to flow from the first intake port into a sensor chamber that houses a sensor element that detects odor components, and discharging the gas from the first exhaust port. The cleaning step includes stopping the first gas delivery unit, driving the second gas delivery unit, connecting a second exhaust port provided in the sensor chamber to a second intake port provided in the sensor chamber, causing gas to flow from the sensor chamber through the second exhaust port into a flow path having a filter therein that removes the odor components, and causing gas to flow from the flow path into the sensor chamber through the second intake port. Effect of the Invention

[0014] As described above, according to the present invention, it is possible to provide an odor detection device and an odor detection method that are simple in structure and have a high cleaning effect. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view of an odor detection device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of the odor detection device as seen from a different direction. [Diagram 3] FIG. 2 is an exploded perspective view of the odor detection device. [Figure 4] FIG. 2 is a schematic diagram showing a schematic configuration of the odor detection device. [Diagram 5] FIG. 2 is a perspective view of a sensor unit included in the odor detection device. [Figure 6] FIG. 2 is a perspective view of a sensor module included in the sensor unit. [Figure 7] FIG. 2 is a perspective view showing a part of the sensor module. [Figure 8] FIG. 2 is a cross-sectional view of the sensor module. [Figure 9] 4 is a plan view of a wiring board included in the sensor module. FIG. [Figure 10] FIG. 2 is a perspective view of a lower case of the odor detection device. [Figure 11] FIG. 4 is a perspective view of the lower case as viewed from a different direction. [Figure 12] FIG. 2 is a perspective view of an upper case of the odor detection device. [Figure 13] FIG. 4 is a perspective view of the upper case as viewed from a different direction. [Figure 14] FIG. 2 is a perspective view of the upper case and the filter. [Figure 15] FIG. 2 is a perspective view showing a circulation flow path provided in the odor detection device. [Figure 16] FIG. 2 is a perspective view showing a circulation flow path provided in the odor detection device. [Figure 17] 2 is a plan view showing a circulation flow path provided in the odor detection device. FIG. [Figure 18] FIG. 2 is a schematic diagram showing a detection flow of the odor detection device. [Figure 19] 10A and 10B are schematic diagrams showing a detection flow in the upper case. [Figure 20] 5A to 5C are schematic diagrams showing a detection flow in the upper sensor unit. [Figure 21] 5A to 5C are schematic diagrams showing a detection flow in the sensor module. [Figure 22] 10A and 10B are schematic diagrams showing a detection flow in the lower case. [Figure 23] 5 is a schematic diagram showing a cleaning flow of the odor detection device. FIG. [Figure 24] 5A to 5C are schematic diagrams showing a cleaning flow in the sensor module. [Diagram 25] 5A to 5C are schematic diagrams showing a cleaning flow in the sensor unit. [Figure 26] 5A to 5C are schematic diagrams showing a cleaning flow in the lower case. [Figure 27] FIG. 2 is a schematic diagram showing a schematic configuration of an odor detection device according to a comparative example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An odor detection device according to an embodiment of the present invention will be described.

[0017] [Configuration of the odor detection device] Fig. 1 is a perspective view of odor detection device 100 according to this embodiment, and Fig. 2 is a perspective view of odor detection device 100 seen from a different direction than Fig. 1. Fig. 3 is an exploded perspective view of odor detection device 100, and Fig. 4 is a schematic diagram showing the general configuration of odor detection device 100. In each figure, three mutually orthogonal directions are defined as X-axis directions, Y-axis directions, and Z-axis directions.

[0018] First, a schematic diagram will be described with reference to Fig. 4. As shown in Fig. 4, odor detection device 100 includes a sensor chamber 171, a sensor element 154, a flow path 101, a first pump 152, a second pump 153, and a filter 181. Sensor chamber 171 is provided with a first intake port 172, a second intake port 173, a first exhaust port 174, and a second exhaust port 175, and accommodates sensor element 154.

[0019] Second exhaust port 175 is connected to second intake port 173 by flow path 101. First pump 152 causes the gas to be measured to flow into sensor chamber 171 from first intake port 172 and exhaust it from first exhaust port 174. Meanwhile, second pump 153 causes the gas to flow from sensor chamber 171 into flow path 101 via second exhaust port 175, and causes the gas to flow from flow path 101 into sensor chamber 171 via second intake port 173. Filter 181 is disposed in flow path 101.

[0020] Therefore, the gas to be measured is measured by sensor element 154 in the sensor chamber, and then purified (cleaned) by filter 181 arranged in flow path 101, and flows again into sensor chamber 171. In this way, when cleaning, the gas (air) inside sensor chamber 171 can be circulated multiple times, and the filter size can be reduced.

[0021] If gas from the outside were to be cleaned, it would be necessary to clean all impurities at once, which would require a large amount of filters; however, if the gas is circulated, it would pass through the same filter 181 many times, which would reduce the amount of filters 181 and therefore the filter size could be reduced accordingly, resulting in a smaller size. Since the degree of cleanliness increases with each circulation, the sensor can be refreshed with a highly clean cleaning gas. This can extend the life of the sensor element 154. It is required that the cleaning gas be free of unnecessary components and have a stable degree of cleanliness, and this circulation allows a stable gas to be supplied.

[0022] These components are formed by sensor unit 111, lower case 112, upper case 113, and lid 114 shown in Fig. 3. Sensor unit 111 incorporates a sensor module 150. Fig. 5 is a perspective view of sensor unit 111, and Fig. 6 is a perspective view of sensor module 150.

[0023] The sensor unit 111 has a sensor housing 121. As shown in Fig. 5, the sensor housing 121 is a hollow box-shaped member that houses the sensor module 150. The sensor housing 121 has a rectangular parallelepiped shape, and has an upper surface 121a, a lower surface 121b, and side surfaces 121c. The upper surface 121a and the lower surface 121b are located opposite each other. In the case of the rectangular parallelepiped shape, the side surfaces 121c are made up of four surfaces.

[0024] A first opening 122 and a second opening 123 are provided on the top surface 121a. A third opening 124 and a fourth opening 125 are provided on one surface of the side surface 121c. Gas enters through the first opening 122 and the second opening 123 and is exhausted through the third opening 124 and the fourth opening 125. Of the side surface 121c, the surface on which the third opening 124 and the fourth opening 125 are provided and the opposing surface thereof may be made of aluminum, and the other surfaces may be made of resin. The top surface 121a and the bottom surface 121b may be made of aluminum.

[0025] As shown in Fig. 6, sensor module 150 includes case 151, first pump 152, second pump 153, and sensor element 154. Fig. 7 to Fig. 9 are diagrams showing the internal structure of sensor module 150, with Fig. 7 being a perspective view seen through case 151, Fig. 8 being a cross-sectional view of sensor module 150, and Fig. 9 being a plan view of the inside of wiring board 161. As shown in Fig. 8, case 151 includes wiring board 161 and case main body 162, which are assembled together.

[0026] 8, wiring board 161 has first main surface 161a on which sensor element 154 is mounted, and second main surface 161b on the opposite side. First main surface 161a is an inner main surface facing case body 162, and the inner surface of case body 162 and first main surface 161a of wiring board 161 form an internal space. Second main surface 161b is an outer main surface.

[0027] Wiring board 161 is a rectangular board with its long sides in the X-axis direction, and is a double-sided wiring board having wiring layers formed on first main surface 161a and second main surface 161b. Wiring board 161 is typically a glass epoxy board, but other rigid boards such as ceramic boards and metal boards can also be used.

[0028] The case body 162 is a shape in which one surface of a substantially rectangular parallelepiped is removed to form an opening. The opening is opened on the side in contact with the wiring board 161, and an opening end 162a is provided. In this embodiment, the opening is formed by removing one surface parallel to the XY plane. The opening end 162a, which is the lower end of the side wall forming the opening of the case body 162, is adhered and fixed to the periphery of the first main surface 161a of the wiring board 161 so as to maintain airtightness. The case body 162 has a bottom 162b (space wall), and the bottom 162b is located in a position facing the first main surface 161a of the wiring board 161. In this manner, a sensor chamber 171 is formed between the wiring board 161 and the case body 162.

[0029] In this embodiment, case body 162 is fixed to wiring board 161 by a plurality of screws 155 (see FIG. 6). A seal member (such as a packing) (not shown) is disposed between first main surface 161a of wiring board 161 and opening end 162a of case body 162, thereby ensuring airtightness between wiring board 161 and case body 162. Case body 162 is, for example, an injection-molded body made of a synthetic resin material. The type of resin material is not particularly limited and is, for example, polytetrafluoroethylene.

[0030] Case 151 (see FIG. 6) has a sensor chamber 171, a first intake port 172, a second intake port 173, a first exhaust port 174, and a second exhaust port 175. First intake port 172 and second intake port 173 are provided in wiring board 161, and first exhaust port 174 and second exhaust port 175 are provided in case main body 162. Case 151 does not have any openings other than first intake port 172, second intake port 173, first exhaust port 174, and second exhaust port 175.

[0031] The sensor chamber 171 (see FIG. 8) has a first chamber 171a and a second chamber 171b. The first chamber 171a is formed between the first main surface 161a and the bottom surface 162c, and the second chamber 171b is formed between the first main surface 161a and the bottom surface 162d. The first chamber 171a communicates with a first intake port 172 and a second intake port 173, and the second chamber 171b communicates with a first exhaust port 174 and a second exhaust port 175.

[0032] 8, if the distance between the first main surface 161a and the bottom surface 162c in the first chamber 171a is distance D1, and the distance between the first main surface 161a and the bottom surface 162d in the second chamber 171b is distance D2, then the distance D1 can be made larger than the distance D2. As a result, a step 162e is formed at the boundary between the first chamber 171a and the second chamber 171b.

[0033] The step portion 162e is a wall surface extending along the Y-axis direction between the first intake port 172 and the second intake port 173 and the first exhaust port 174 and the second exhaust port 175, and functions as a throttle that restricts the flow path of gas flowing from the first chamber 171a to the second chamber 171b.

[0034] Specifically, the gas that flows into the first chamber 171a from the first intake port 172 or the second intake port 173 is restricted from flowing into the second chamber 171b by the step 162e, and as a result, the gas is isotropically diffused in a turbulent state within the first chamber 171a. Furthermore, the gas that flows into the first chamber 171a flows into the second chamber 171b in a laminar flow state due to the restriction caused by the step 162e.

[0035] This allows the gas that has flowed into first chamber 171a to be uniformly supplied throughout second chamber 171b regardless of the positions of first suction port 172 and second suction port 173. Furthermore, since first suction port 172 and second suction port 173 are provided in wiring board 161 so as to face the bottom (bottom surface 162c) of first chamber 171a, the gas diffusion effect in first chamber 171a can be further improved.

[0036] Incidentally, the step portion 162e is not necessarily provided, and the bottom surface 162c and the bottom surface 162d may be on the same plane. Even if the bottom surface 162c and the bottom surface 162d are on the same plane, a wall extending from the bottom portion 162b toward the first main surface 161a may be provided between the bottom surface 162c and the bottom surface 162d to provide a throttling function equivalent to that of the step portion 162e.

[0037] The first suction port 172 and the second suction port 173 are each a through hole provided in the wiring board 161. The shapes of the first suction port 172 and the second suction port 173 are not limited to the rectangular shape shown in the figure, and may be circular. The first suction port 172 and the second suction port 173 may be formed in a region on one side (-X-axis direction side) of the wiring board 161 so as to be adjacent to each other in the Y-axis direction, as shown in FIG.

[0038] The first exhaust outlet 174 and the second exhaust outlet 175 are each a through hole provided in the case main body 162. The shapes of the first exhaust outlet 174 and the second exhaust outlet 175 are not limited to the circular shape shown in the figure, and may be rectangular or the like. The first exhaust outlet 174 and the second exhaust outlet 175 are preferably approximately the same in size. The first exhaust outlet 174 and the second exhaust outlet 175 can be formed adjacent to each other in the Y-axis direction on the side wall on the other side (+X-axis direction side) of the case main body 162, as shown in FIG. 9.

[0039] The positional relationship between the first intake port 172, the second intake port 173, the first exhaust port 174, and the second exhaust port 175 is not particularly limited, but it is preferable that the first intake port 172 and the first exhaust port 174 are located on opposite sides of the sensor element 154 in the sensor chamber 171. It is also preferable that the second intake port 173 and the second exhaust port 175 are located on opposite sides of the sensor element 154 in the sensor chamber 171. Specifically, as shown in FIG. 8, the first intake port 172 and the second intake port 173 are disposed close to one end of the wiring board 161 in the longitudinal direction (X-axis direction), and the first exhaust port 174 and the second exhaust port 175 can be provided in a side wall 162f joined to the other end of the wiring board 161 in the longitudinal direction (X-axis direction). By positioning the first intake port 172 and the second intake port 173 and the first exhaust port 174 and the second exhaust port 175 on opposite sides of the sensor element 154, gas can be efficiently caused to flow into the sensor element 154.

[0040] The first pump 152 is provided in the first intake port 172 and delivers gas from the first intake port 172 into the sensor chamber 171. The second pump 153 is provided in the second intake port 173 and delivers gas from the second intake port 173 into the sensor chamber 171. The first pump 152 and the second pump 153 can be disposed on the second main surface 161b of the wiring board 161. The type of the first pump 152 and the second pump 153 is not particularly limited, but a pump that does not allow gas to pass easily during a stop of operation is preferable, and a diaphragm pump is particularly preferable. Note that the odor detection device 100 may be provided with a pump capable of delivering gas instead of the first pump 152. For example, a fan may be provided. Also, the odor detection device 100 may be provided with a pump capable of delivering gas instead of the second pump 153. For example, a fan may be provided.

[0041] The sensor element 154 detects odor components. For example, a QCM (Quartz Crystal Microbalance) sensor can be used as the sensor element 154. The QCM sensor has a configuration in which a sensitive film for adsorbing the detection target component is provided on the electrode surface of a quartz oscillator. When the detection target component is adsorbed to the electrode surface of the quartz oscillator, the resonant frequency fluctuates (decreases) according to the mass, so that minute changes in mass can be detected. The QCM sensor can detect different components depending on the material of the sensitive film, and each sensor element 154 can be capable of detecting a different odor component. The sensor element 154 may be a sensor other than a QCM sensor.

[0042] The odor components detected by the sensor element 154 are typically relatively heavy molecules in the air, such as polymer compounds, but are not particularly limited thereto. The odor components detected by the sensor element 154 are not limited to components that humans can detect with their sense of smell, and may be any chemical species present in the gas.

[0043] The sensor module 150 has eight sensor elements 154, and by using a different sensitive film for each sensor element 154, eight types of odor components can be detected. Note that the present invention is not limited to an example in which one type of odor component is detected by one sensor element 154, and one type of odor component may be detected by multiple sensor elements 154. Also, one sensor element 154 may be configured to be able to detect multiple types of odor components. In this case, it is preferable to use sensitive films with different sensitivities depending on the odor components.

[0044] Sensor element 154 is mounted on first main surface 161a of wiring board 161 facing sensor chamber 171. In this embodiment, an example in which eight sensor elements 154 are arranged in two rows and four columns is shown, but the layout is not limited to this. In addition, the number of sensor elements 154 is not limited to eight, and can be set arbitrarily depending on the number of components to be detected, and may be one.

[0045] A temperature sensor 156 and a humidity sensor 157 may be mounted on the first main surface 161a of the wiring board 161. The mounting areas of the temperature sensor 156 and the humidity sensor 157 are not particularly limited, and in this embodiment, they are disposed in any area between the sensor element 154 and the first exhaust port 174 and the second exhaust port 175. When the QCM characteristics of the sensor element 154 have temperature dependency, the output of the sensor element 154 is corrected based on the output of the temperature sensor 156.

[0046] The humidity sensor 157 may be used as a sensor for detecting water vapor, for example. A thermistor may be used as the temperature sensor 156, and a QCM sensor having a sensitive film that is adsorbent to water vapor may be used as the humidity sensor 157.

[0047] 6, a control board 158 is installed on the second main surface 161b side of the wiring board 161. A power supply circuit and a signal processing circuit are connected to the control board 158. The control board 158 is electrically connected to the wiring board 161, and supplies necessary power to each of the sensor elements 154, the first pump 152, the second pump 153, the temperature sensor 156, and the humidity sensor 1157 via the wiring layer on the wiring board 161.

[0048] The signal processing circuit detects the presence or absence, type, amount, etc. of the detection target component in sensor chamber 171 based on the outputs of each sensor element 154, temperature sensor 156, and humidity sensor 157. Note that control board 158 may be equipped with other electronic components (e.g., drive circuits for first pump 152 and second pump 153, etc.) in addition to the above elements or sensors.

[0049] The sensor module 150 has the configuration described below. As described above, the sensor module 150 is housed in the sensor housing 121 (see FIG. 5) and fixed to the sensor housing 121 with the wiring board 161 facing the upper surface 121a (opposite to that in FIG. 6). As a result, the first intake port 172 is connected to the first opening 122 with the first pump 152 in between, and the second intake port 173 is connected to the second opening 123 with the second pump 153 in between. In addition, the first exhaust port 174 is connected to the third opening 124, and the second exhaust port 175 is connected to the fourth opening 125.

[0050] Lower case 112 is a member that holds sensor unit 111 and is made of, for example, resin. Fig. 10 is a perspective view of lower case 112, and Fig. 11 is a perspective view of lower case 112 seen from another direction. As shown in these figures, lower case 112 has a bottom surface portion 112a, a side wall portion 112b, and a fixing portion 112c.

[0051] Bottom surface portion 112a is a flat plate-like portion and abuts against lower surface 121b (see FIG. 5) of sensor housing 121. Side wall portion 112b is provided on the periphery of bottom surface portion 112a in the form of a perpendicular surface to bottom surface portion 112a and abuts against a side surface 121c of sensor housing 121. Fixing portion 112c is provided on side wall portion 112b and is used for fixing to upper case 113. Furthermore, an opening 131 and a tubular portion 132 are provided adjacent to each other on side wall portion 112b.

[0052] The opening 131 is an opening that penetrates the side wall portion 112b, and is connected to the third opening 124 (see FIG. 5) when the sensor unit 111 is housed in the lower case 112. The tubular portion 132 has a tube 132a, a tube opening 132b (see FIG. 11), and a tube opening 132c (see FIG. 10). The tube 132a connects the tube opening 132b and the tube opening 132c. The tube opening 132b is a tube opening that penetrates the side wall portion 112b, and is connected to the fourth opening 125 (see FIG. 5) when the sensor unit 111 is housed in the lower case 112. The tube opening 132c is a tube opening facing upward (in the +Z direction), and is connected to a tube opening provided in the upper case 113.

[0053] Upper case 113 is a member that is connected to lower case 112 and forms an introduction space and a flow path space, and is made of, for example, resin. Fig. 12 is a perspective view of upper case 113, and Fig. 13 is a perspective view of upper case 113 as viewed from another direction.

[0054] As shown in these figures, upper case 113 has bottom surface portion 113a, side wall portion 113b, inner wall portion 113c, fixing portion 113d, and fixing portion 113e. Bottom surface portion 113a is a flat plate-shaped portion and abuts against upper surface 121a of sensor housing 121 (see FIG. 5). Bottom surface portion 113a is provided with a first opening 141 and a second opening 142. First opening 141 and second opening 142 are each an opening that penetrates bottom surface portion 113a.

[0055] When upper case 113 is attached to sensor unit 111, first opening 141 is connected to first opening 122 of sensor housing 121. When upper case 113 is attached to sensor unit 111, second opening 142 is connected to second opening 123 of sensor housing 121.

[0056] The side wall portion 113b is provided on the periphery of the bottom surface portion 113a in a perpendicular plane relative to the bottom surface portion 113a and abuts against the side surface 121c of the sensor housing 121. An opening 113f is provided in the side wall portion 113b. The inner wall portion 113c is provided inside the bottom surface portion 113a in a perpendicular plane relative to the bottom surface portion 113a and forms an introduction space and a flow path space described below together with the side wall portion 113b. The fixing portion 113d is provided on the side wall portion 113b and is used for fixing to the lower case 112. The fixing portion 113e is provided on the side wall portion 113b and is used for fixing to the lid 114.

[0057] Furthermore, the side wall portion 113b is provided with a tubular portion 144. The tubular portion 144 has a tube 144a, a tube opening 144b (see FIG. 13), and a tube opening 144c (see FIG. 12). The tube 144a connects the tube opening 144b and the tube opening 144c. The tube opening 144b is a tube opening facing downward (-Z direction), and is connected to the tube opening 132c (see FIG. 10) of the lower case 112. The tube opening 144c is a tube opening that penetrates the side wall portion 113b.

[0058] 12 shows the introduction space 143 and the flow path space 145 formed by the upper case 113. The introduction space 143 is a space between the bottom surface portion 113a, the side wall portion 113b, the inner wall portion 113c, and the opening 113f, and communicates with the first opening 141. The flow path space 145 is a space between the bottom surface portion 113a, the side wall portion 113b, and the inner wall portion 113c, and is isolated from the introduction space 143 by the inner wall portion 113c. The flow path space 145 communicates with the pipe port 144c and the second opening 142.

[0059] Lid 114 is a member that is joined to upper case 113 and closes the top surface of upper case 113 (see FIG. 3), and is made of, for example, resin. Lid 114 seals flow path space 145 and seals introduction space 143 except for opening 113f (see FIG. 12). A sealing member such as a packing may be disposed between lid 114 and upper case 113. Lid 114 is a flat plate-like member and has fixing portion 114a provided on the periphery. Fixing portion 114a is used for fixing to upper case 113.

[0060] The filter 181 is housed in the flow path space 145 and removes odor components from the gas flowing through the flow path space 145. The filter 181 is a filter capable of removing at least the odor components that are the detection targets of the sensor elements 154. FIG. 14 is a schematic diagram showing the filter 181 housed in the flow path space 145. As shown in the figure, the filter 181 can be housed throughout the entire flow path space 145. The filter 181 may be housed in only a part of the flow path space 145, but it is preferable that the filter 181 occupies most of the flow path space 145.

[0061] [About the flow path] In the odor detection device 100, a flow path 101 (see FIG. 4) is formed by the tubular portion 132 of the lower case 112, the tubular portion 144 of the upper case 113, and the flow path space 145. FIG. 15 is a schematic diagram showing a part of the flow path 101. As shown in the figure, the tubular portion 132 of the lower case 112 and the tubular portion 144 of the upper case 113 are joined, and the pipe opening 132b (see FIG. 11) and the pipe opening 144c (see FIG. 12) communicate with each other.

[0062] As a result, a flow path 101 (see FIG. 4) is formed that extends from the second exhaust port 175 (see FIG. 7) through the tubular portion 132, the tubular portion 144, and the flow path space 145 to the second intake port 173. FIG 16 is a perspective view showing the flow path 101 in the flow path space 145, and FIG 17 is a plan view showing the shape of the flow path 101 in the flow path space 145.

[0063] 17, the flow channel 101 includes a first portion 101a, a second portion 101b, and a third portion 101c in the flow channel space 145. The first portion 101a extends in one direction (+Y axis direction) parallel to the bottom surface portion 113a (XY plane). The second portion 101b is downstream of the first portion 101a and extends in the opposite direction (-Y axis direction) to the first portion 101a. The third portion 101c is downstream of the second portion 101b and extends in the same direction (+Y axis direction) as the first portion 101a.

[0064] By forming the flow path 101 in a meandering shape in this manner, the length of the flow path 101 can be made as long as possible within the size of the upper case 113. Note that the shape of the flow path space 145 is not limited to this, and it may be another shape that can realize a flow path from the pipe opening 144c to the second opening 142.

[0065] Odor detection device 100 has the above-mentioned configuration. As shown in Fig. 3, odor detection device 100 is formed by stacking lower case 112, sensor unit 111, upper case 113, and lid 114 in this order, and fixing parts 112c and 113d, and fixing parts 113e and 114a by screws or the like.

[0066] In this structure, flow path 101 is provided above sensor chamber 171, so it is possible to reduce the size of odor detection device 100 while providing flow path 101. Flow path 101 can also be provided below sensor chamber 171. The size of odor detection device 100 is not particularly limited, but can be, for example, a length (X-axis direction) of 70 to 90 mm, a width (Y-axis direction) of 65 to 85 mm, and a height (Z-axis direction) of 50 to 70 mm.

[0067] [Gas flow] In odor detection device 100, two types of gas flows are formed: a gas flow for odor detection (hereinafter, detection flow) and a gas flow for cleaning (hereinafter, cleaning flow).

[0068] 18 to 22 are schematic diagrams showing a detection flow. In the detection flow, the first pump 152 is driven and the second pump 153 is stopped. Hereinafter, this state of the odor detection device 100 is referred to as a first state. In the first state, as shown by the arrow F1 in FIG. 18, gas flows into the sensor chamber 171 from the first intake port 172 and is discharged from the first exhaust port 174. More specifically, the gas flows into the introduction space 143 from the opening 113f (see FIG. 19), passes through the first opening 141 and the first opening 122 (see FIG. 20), and flows into the sensor chamber 171 from the first intake port 172 (see FIG. 21). Furthermore, the gas is discharged from the first exhaust port 174 through the third opening 124 (see FIG. 20) and the opening 131 (see FIG. 22).

[0069] 23 to 27 are schematic diagrams showing a cleaning flow. In the cleaning flow, first pump 152 is stopped and second pump 153 is driven. Hereinafter, this state of odor detection device 100 will be referred to as the second state. In the second state, as shown by arrow F2 in FIG. 23, gas flows from sensor chamber 171 into flow path 101 via second exhaust port 175, and then flows from flow path 101 into sensor chamber 171 via second intake port 173. Furthermore, gas flows from sensor chamber 171 through second exhaust port 175 again into flow path 101, and thereafter circulates between flow path 101 and sensor chamber 171.

[0070] More specifically, the gas flows from sensor chamber 171 through second outlet 175 (see FIG. 24) and fourth opening 125 (see FIG. 25) into flow path 101 (see FIGS. 15 and 16). The gas then flows from flow path 101 through second opening 142 and second opening 123 (see FIG. 25) into sensor chamber 171 and circulates.

[0071] [Operation of odor detection device] The operation of odor detection device 100 will be described. In odor detection device 100, detection of odor components and cleaning are performed. In detecting odor components, as described above, first pump 152 is driven and second pump 153 is stopped (first state) to generate a detection flow (see FIG. 18). This causes outside air in the vicinity of odor detection device 100 to be drawn into sensor chamber 171. Odor components contained in the outside air are adsorbed to the sensitive membrane of each sensor element 154 and detected. After detection of odor components, cleaning is performed.

[0072] In the cleaning, as described above, the first pump 152 is stopped and the second pump 153 is driven (second state) to generate a cleaning flow (see FIG. 23). As a result, the gas in the sensor chamber 171 is sucked into the flow path 101, and the odor components in the gas are removed by the filter 181. The odor components adsorbed to the sensor element 154 gradually desorb from the sensor element 154 as the odor components in the gas become diluted, and are removed by the filter 181. By performing cleaning for a certain period of time, the gas passes through the flow path 101 many times, and the odor components are removed by the filter 181, so that the odor components adsorbed to the sensor element 154 are removed and cleaning (refreshing) is completed. This provides a high cleaning effect. This cleaning refreshes the sensor element 154, making it possible to perform the next detection.

[0073] When the detection flow (see FIG. 18) is being performed, flow path 101 is a closed path, so that no gas flows and the odor components to be detected are not removed by filter 181. When the cleaning flow (see FIG. 23) is being performed, outside air can enter sensor chamber 171 via first exhaust port 174 or first pump 152 which is stopped.

[0074] However, by making first pump 152 impermeable to gas while a diaphragm pump or the like is stopped, it is possible to prevent outside air from flowing in from first pump 152. Even when outside air flows in from first exhaust port 174, since first pump 152 is the only outlet from sensor chamber 171, by making first pump 152 impermeable to gas while it is stopped, it is possible to almost completely prevent outside air from flowing in to sensor chamber 171.

[0075] Therefore, in odor detection device 100, it is possible to switch between the inspection flow and the cleaning flow by switching between first pump 152 and second pump 153, and there is no need to switch between valves or pipelines. Note that switching between the first state and the second state may be performed by a user, or may be performed by a control unit capable of controlling the driving of first pump 152 and second pump 153, respectively. The control unit may be mounted on control board 158 (see FIG. 6), for example.

[0076] [Effects of odor detection devices] The effects of odor detection device 100 will be explained in comparison with a conventional structure. Fig. 27 is a schematic diagram of odor detection device 200 having a conventional structure. As shown in the figure, odor detection device 200 includes a sensor chamber 271, a sensor element 254, a flow path 201, a first pump 252, a second pump 253, and a filter 281.

[0077] Sensor chamber 271 is provided with first suction port 272, second suction port 273, and exhaust port 274, and accommodates sensor element 254. Flow path 201 is connected to second suction port 273, and filter 281 is arranged in flow path 201. First pump 252 causes gas to flow from first suction port 272 into sensor chamber 271. Second pump 253 causes gas to pass through flow path 201 and flow from second suction port 273 into sensor chamber 271.

[0078] In odor detection device 200, when detecting odor components, first pump 252 is driven and second pump 253 is stopped. This causes outside air to flow into sensor chamber 271 from first intake port 272 and be discharged from exhaust port 274. Sensor element 254 adsorbs and detects odor components in the gas.

[0079] In odor detection device 200, cleaning is also performed after detection of odor components. In cleaning, first pump 252 is stopped and second pump 253 is driven. As a result, outside air passes through flow path 201 and flows into sensor chamber 271 from second intake port 273, and is discharged from exhaust port 274. As the outside air passes through flow path 201, odor components are removed by filter 281, and sensor element 254 is cleaned by the gas from which the odor components have been removed.

[0080] Here, in the odor detection device 200, as described above, it is necessary to remove odor components from the outside air flowing into the flow path 201 by the filter 281. The amount of odor components to be removed may be large depending on the environment, and the amount of odor components adsorbed by the filter 281 continues to increase as the cleaning time passes. For this reason, the filter 281 needs to be a strong filter or a large filter. Furthermore, when the outside air contains a large amount of odor components, the removal effect of the filter 281 becomes small, the cleaning time becomes long, and the life of the filter 281 becomes short.

[0081] On the other hand, it is also possible to perform cleaning by supplying a separate clean gas into the sensor chamber instead of using outside air for cleaning. In this case, it is necessary to switch between the detection flow path and the clean gas flow path using a valve or the like, making the device complex and large-scale.

[0082] 23, in odor detection device 100, gas is circulated through flow path 101 and sensor chamber 171 during cleaning, and odor components are removed by filter 181. The more the circulation is repeated, the more odor components are removed, making it possible to supply clean gas to sensor element 154.

[0083] Also, since the amount of odor components to be removed is only the amount contained in sensor chamber 171 and flow path 101 at the start of cleaning and the amount adsorbed to sensor element 154, it is not as large as in conventional structures, and filter 181 can be made smaller in size and has a longer life. Furthermore, the detection flow and cleaning flow can be switched by selecting the pump to be driven, and no valve operation is required, making control easy. Therefore, odor detection device 100 has a simple structure and a high cleaning effect.

[0084] In addition, odor detection device 100 has a structure in which sensor unit 111 including sensor chamber 171 and upper case 113 including filter 181 are stacked together, which makes it possible to reduce the size of the device.

[0085] Furthermore, by providing step 162e having a throttling function in sensor chamber 171, the gas flowing into first chamber 171a can be uniformly supplied throughout second chamber 171b. As a result, in the detection flow, outside air can be uniformly supplied to multiple sensor elements 154, improving detection accuracy. Also, in the cleaning flow, odor components adsorbed to each sensor element 154 can be quickly removed.

[0086] [Variations] Although odor detection device 100 is configured with sensor unit 111, lower case 112, upper case 113, and lid 114, the present invention is not limited to this, and other configurations that can realize the schematic configuration shown in Fig. 4 are also possible. Furthermore, the configuration shown in Fig. 4 can be modified within the scope of being able to execute the above-mentioned detection flow and cleaning flow. For example, first pump 152 may be disposed inside sensor chamber 171 (near first intake port 172), and second pump 153 may also be disposed inside sensor chamber 171 (near second intake port 173). Second pump 153 may be provided upstream of filter 181 in flow path 101. Furthermore, first exhaust port 174 may be provided with a check valve that prevents outside air from entering. [Explanation of symbols]

[0087] 100...Detection device 101...Circulation flow path 111…Sensor unit 112…Lower case 113…Upper case 114…Lid 150…Sensor module 151…Casing 152…First pump 153…Second pump 154...Sensor element 171…Sensor room 172...1st intake port 173…Second intake port 174…1st discharge port 175…Second discharge port 181…Filter

Claims

1. a sensor chamber in which a sensor element is housed, the sensor chamber having a first intake port, a first exhaust port provided on a side opposite the first intake port with respect to the sensor element, a second intake port, and a second exhaust port provided on a side opposite the second intake port with respect to the sensor element; a flow path having a filter therein, connected to the second outlet, and connected to the second inlet; a first gas delivery unit that causes gas to flow into the sensor chamber from the first intake port and discharges the gas from the first exhaust port; a second gas delivery section that causes gas to flow from the sensor chamber into the flow path through the second exhaust port and causes gas to flow from the flow path into the sensor chamber through the second intake port; An odor detection device comprising:

2. The odor detection device according to claim 1, The flow path is provided above or below the sensor chamber so as to overlap with the sensor chamber when viewed from above. Odor detection device.

3. The odor detection device according to claim 2, The flow path has a meandering shape in a plane perpendicular to the up-down direction of the odor detection device.

4. The odor detection device according to claim 3, The flow path has a first portion extending in a first direction, a second portion extending in a second direction downstream of the first portion, the second direction being opposite to the first direction, and a third portion extending in the first direction downstream of the second portion. Odor detection device.

5. The odor detection device according to any one of claims 1 to 4, The sensor chamber includes a first chamber in which the first intake port and the second intake port are provided, a second chamber in communication with the first chamber and in which the first exhaust port and the second exhaust port are provided, and a throttle portion that restricts the flow of gas from the first chamber to the second chamber. Odor detection device.

6. The odor detection device according to any one of claims 1 to 5, a control unit that switches between a first state in which the first gas delivery unit is operated and the second gas delivery unit is stopped and a second state in which the first gas delivery unit is stopped and the second gas delivery unit is operated; The odor detection device further comprises:

7. a detection step of driving the first gas delivery unit, stopping the second gas delivery unit, and causing gas to flow from the first intake port into a sensor chamber accommodating a sensor element that detects odor components, and discharging the gas from the first exhaust port; a cleaning step of stopping the first gas delivery unit, driving the second gas delivery unit, connecting a second exhaust port provided in the sensor chamber to a second intake port provided in the sensor chamber, causing gas to flow from the sensor chamber through the second exhaust port into a flow path having a filter therein for removing the odor component, and causing gas to flow from the flow path into the sensor chamber through the second intake port; An odor detection method comprising:

Images