Odor measuring device, control device, and odor determining method

Abstract

[Problem] To provide an odor measurement device, a control device, and an odor identification method that have high odor identification accuracy. [Solution] An odor measurement device comprises a sensor, a housing chamber, a first pump, a second pump, and a control device. The sensor has an adsorption film for adsorbing an odor substance, and outputs a signal in response to adsorption of the odor substance. The housing chamber houses the sensor. The first pump feeds a first gas containing an odor substance to the housing chamber. The second pump feeds, to the housing chamber, a second gas for desorbing the odor substance from the adsorption film. The control device has an identification unit. The identification unit measures the odor substance that was adsorbed by the adsorption film on the basis of output signal information from the sensor in the process of desorbing the odor substance.

Description

[Technical field]

[0001] The present invention relates to an odor measuring device, a control device, and an odor determining method. [Background technology]

[0002] In an odor measuring device using an odor sensor, odors are measured by utilizing the change in the electrical characteristics of the odor sensor when odorous substances contained in the gas to be measured adhere to the sensitive part of the odor sensor (see, for example, Patent Document 1). In odor measuring devices, the sensing part needs to be cleaned after measuring one odor sample. If the cleaning process is not performed, odor substances that have adhered to the sensing part during the previous measurement will cause measurement errors when measuring the next odor sample. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-64554 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above cleaning process is time-consuming and inefficient in order to completely remove odorants adhering to the sensing part, and there is also the problem that insufficient cleaning results in poor measurement accuracy.

[0005] In view of the above circumstances, an object of the present invention is to provide an odor measuring device, a control device, and an odor determination method that have high odor determination accuracy. [Means for solving the problem]

[0006] In order to achieve the above object, an odor measuring device according to one embodiment of the present invention includes a sensor, a storage chamber, a first pump, a second pump, and a control device. The sensor has an adsorption film that adsorbs odorous substances, and outputs a signal in response to the adsorption of the odorous substance. The storage chamber houses the sensor. The first pump comprises: the above A first gas containing an odorant is supplied to the storage chamber. The second pump supplies a second gas to the storage chamber, which causes the odorant to desorb from the adsorption film. The control device includes a control unit and a determination unit. above In the containment room above Supplying the first gas The adsorption film is exposed to the first gas until the adsorption and desorption of the odorant to the adsorption film reaches a substantially equilibrium state. The first mode, above In the containment room above The second mode of supplying the second gas can be executed in sequence. above In the first mode above The adsorbed on the adsorption film above The odorant is above In the second mode above In the desorption process from the adsorption film above Based on the output signal information of the sensor, above Identify the odorant.

[0007] According to this configuration of the present invention, the measurement for odor determination is started from a state where the odor substance is adsorbed on the adsorption film, and the odor determination is performed based on the change in the output signal of the sensor measured when the odor substance is desorbed from the adsorption film. This allows the adsorption state of the adsorption film at the start of the measurement to always be in a state where the odor substance to be measured is almost saturated and adsorbed, improving the accuracy of the odor determination.

[0008] The control unit may execute the first mode for a longer period than the second mode. .

[0009] The determination unit may determine the odor substance by referring to information on changes in the output signal during the desorption process for each different odor substance, which is measured in advance by the sensor.

[0010] The change information of the output signal during the desorption process is measured in advance under different humidity conditions, The determination unit may determine the odor substance by using humidity information of the first gas acquired by a humidity sensor and by referring to information on changes in an output signal during the desorption process.

[0011] Further comprising a filter for adsorbing an odor substance contained in the first gas, The second pump supplies the first gas that has passed through the filter to the storage chamber as the second gas.

[0012] The filter may include at least one of activated carbon, silica gel, zeolite, and allophane. By using a filter in this manner, the entire device used for odor determination can be made smaller.

[0013] The sensor may include a plurality of odor sensors having different detection sensitivities depending on the odor substance. This allows for the identification of multiple odor substances and enables more accurate odor identification.

[0014] A control device according to one embodiment of the present invention includes: A control device for measuring an odorant based on output signal information of a sensor having an adsorption film that adsorbs the odorant, The above sensor Accommodation In the containment room above A first gas containing the odorant is supplied. The adsorption film is exposed to the first gas until the adsorption and desorption of the odorant to the adsorption film reaches a substantially equilibrium state. The device has a control unit capable of sequentially executing a first mode and a second mode in which a second gas is supplied to the storage chamber to cause the odorous substance to desorb from the adsorption film, and a judgment unit that judges the odorous substance based on output signal information of the sensor during the desorption process in which the odorous substance adsorbed to the adsorption film in the first mode is desorbed from the adsorption film in the second mode.

[0015] The odor determination method according to one aspect of the present invention includes: a sensor having an adsorption film that adsorbs an odor substance and outputs a signal in response to the adsorption of the odor substance; the above Supplying a first gas containing an odorant The adsorption film is exposed to the first gas until the adsorption and desorption of the odorant to the adsorption film reaches a substantially equilibrium state. Execute the first mode, A second mode is executed after the first mode in which a second gas that causes the odor substance to be desorbed from the adsorption film is supplied to the sensor to desorb the odor substance adsorbed on the adsorption film; The odor substance is measured based on output signal information of the sensor during the desorption process in which the odor substance adsorbed to the adsorption film in the first mode is desorbed from the adsorption film in the second mode. Effect of the Invention

[0016] As described above, according to the present invention, it is possible to provide an odor determination method, a control device, and an odor determination system with high odor determination accuracy. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing the configuration of an odor determination system according to an embodiment of the present invention and the configurations of an odor measurement device and a data terminal that constitute the system. FIG. [Diagram 2] FIG. 2 is a schematic diagram illustrating odor determination according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a flowchart of an odor determination method according to an embodiment of the present invention. [Figure 4] 1A to 1C are diagrams for explaining the operating status of a pump in an odor determination method according to an embodiment of the present invention, and diagrams showing changes over time in frequency change amount based on an output signal from a sensor. [Diagram 5] FIG. 1 is a diagram for comparing the measurement results when two different types of oil are measured using an odor determination method according to an embodiment of the present invention and a conventional odor determination method. [Figure 6] This is a diagram for comparing the shapes of radar charts obtained when two different types of oil are measured using an odor determination method according to an embodiment of the present invention and a conventional odor determination method. [Figure 7] FIG. 1 is a schematic diagram illustrating a conventional odor determination method; [Figure 8] FIG. 1 is a flow chart of a conventional odor determination method. [Figure 9] 1A and 1B are diagrams for explaining the operating status of a pump in a conventional odor determination method and diagrams showing changes over time in frequency change amount based on an output signal from a sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, an odor determination system including a plurality of odor sensors having adsorption films with mutually different adsorption characteristics will be described. In the following description, odor refers to a collection of multiple types of odor substances. In other words, odor substances correspond to the constituent components (odor components) of an odor. The adsorption membrane of each odor sensor has selectivity for the odor substances it adsorbs, so different types of odor substances are adsorbed to the adsorption membrane of each odor sensor. In this embodiment, the type of odor, which is a collection of each odor substance, is determined by comprehensively judging the amount of each odor substance measured by each odor sensor. The details are explained below. [Configuration of the odor detection system] FIG. 1 is a schematic diagram showing the configuration of an odor determination system 1 according to one embodiment of the present invention, and the configurations of an odor measurement device 2 and a data terminal 3 that constitute the system 1. As shown in FIG. 1, the odor determination system 1 includes an odor measurement device 2 and a data terminal 3.

[0019] (Configuration of odor measuring device) The odor measuring device 2 includes a storage chamber 20, a first pump 4A, a second pump 4B, a first supply port 5, a second supply port 6, a filter 7, an outlet 8, a sensor substrate 9, and a control substrate 10. The sensor board 9 and the control board 10 are housed in the housing chamber 20, for example, in a stacked state. The storage chamber 20 is a processing chamber in which a series of processes relating to odor determination are carried out.

[0020] The first pump 4A is provided in the storage chamber 20. By operation of the first pump 4A, a first gas containing the odor to be determined is supplied into the storage chamber 20 via the first supply port 5. The first gas is, for example, a gas in the environment in which the odor measuring device 2 is installed, that is, the gas surrounding the odor measuring device 2, i.e., the outside air. The first gas is indicated by the reference symbol 50 in FIG. 2.

[0021] The second pump 4B is provided in the storage chamber 20. By operating the second pump 4B, the second gas is supplied into the storage chamber 20 through the second supply port 6. The second gas is a gas that causes odor substances adsorbed on the adsorption film of the odor sensor described later to be desorbed from the adsorption film. The second gas is a gas that remains after the first gas has passed through a filter 7 provided in the storage chamber 20. The second gas is indicated by the symbol 51 in FIG. 2. By passing through the filter 7, the odor (or each odor substance that constitutes the odor), moisture, etc. contained in the first gas are removed. In other words, the second gas 51 is a gas different from the first gas 50.

[0022] Activated carbon, silica gel, zeolite, allophane, etc. can be used for the filter 7. Typically, an activated carbon filter is used. It is also possible to supply the second gas into the storage chamber 20 without using a filter. For example, an inert gas or ozone is supplied as the second gas. In this case, it is only necessary to prepare an inert gas or an ozone generator. From the viewpoint of miniaturization of the odor measuring device 2, it is more preferable to use a filter. The gas inside the storage chamber 20 can be exhausted to the outside of the storage chamber 20 via the exhaust port 8 .

[0023] The sensor substrate 9 includes a plurality of odor sensors 90 and a humidity sensor 93 mounted on a wiring substrate. The number of odor sensors 90 may be one or more, and in this embodiment, an example is given in which 16 odor sensors 90 are provided. The wiring substrate is a substrate having a wiring layer.

[0024] The odor sensor 90 detects gas. The odor sensor 90 is, for example, a QCM (Quarts Crystal Microbalance) sensor. The odor sensor 90 has a quartz crystal oscillator 91, electrodes (not shown), and an adsorption film 92. The quartz crystal oscillator 91 may be, for example, an oscillator cut at a cut angle called an AT cut. The quartz crystal oscillator 91 is in the form of a thin plate. On one main surface of the quartz crystal oscillator 91 and the other main surface opposite to the main surface, electrodes are formed by patterning a metal thin film into a predetermined shape. The adsorption film 92 is formed on the electrodes and adsorbs odorous substances.

[0025] The adsorption film 92 that adsorbs odor substances is made of a different material for each odor sensor 90. As described above, the odor contained in the gas to be determined contains one or more odor substances (odor components). The odor substances that are mainly adsorbed by each adsorption film 92 are different. By having multiple odor sensors 90 (16 in this embodiment) and using a different adsorption film 92 for each odor sensor 90, multiple types of odor substances can be detected. Each odor sensor 90 has a different detection sensitivity depending on the odor substance. The material used for the adsorption film is appropriately selected depending on the type of odor substance to be measured. Below, examples of materials used for the adsorption film 92 of each odor sensor 90 are given, and the combination of materials is determined depending on the type of odor to be determined. As the adsorption film, cellulose, fluorine-based polymers, lecithin, phthalocyanine compounds, porphyrin compounds, polyimide, polypyrrole, polystyrene, acrylic polymers, sphingomyelin, polybutadiene, polyisoprene, polyvinyl alcohol-based polymers, UiO-66, MIL-125 (MOF), ZIF-8, etc. can be used.

[0026] The humidity sensor 93 detects the humidity of gases such as the first gas and the second gas supplied into the storage chamber 20 and supplied to the adsorption film 92 of the odor sensor 90. A known humidity sensor can be used as the humidity sensor 93. The humidity sensor detects relative humidity. Hereinafter, humidity refers to relative humidity. Humidity information detected by the humidity sensor 93 is output to the determination unit 15 described later.

[0027] The control board 10 is provided with a power supply circuit, a signal processing circuit, etc. The control board 10 is electrically connected to the sensor board 9, and the power supply circuit supplies the necessary power to each odor sensor 90 and humidity sensor 93 via a wiring layer on the sensor board. The signal processing circuit vibrates each odor sensor 90, and determines the type and strength of the odor to be determined based on the output signals of each odor sensor 90 and humidity sensor 93. The signal processing circuit also controls the driving of the first pump 4A and the second pump 4B. In FIG. 1, the configuration of the control board 10 is mainly shown as a functional block diagram. The control board 10 has an oscillation circuit 11, a detection circuit 12, a communication unit 13, a control unit 14, and a determination unit 15. The communication unit 13, the control unit 14, and the determination unit 15 constitute a control device 16. The control device 16 controls a series of processes related to determining the type of odor, etc.

[0028] The oscillator circuit 11 vibrates the quartz crystal of each odor sensor 90 at a predetermined frequency. For example, the resonant frequency is 9 MHz. The detection circuit 12 detects the resonant frequency of each odor sensor 90. When an odor substance is adsorbed to the adsorption film 92 of each odor sensor 90 while the odor sensor 90 is vibrated at a predetermined frequency by the oscillation circuit 11, the resonant frequency of the quartz crystal oscillator of each odor sensor 90 changes. When an odor substance adsorbed to the adsorption film 92 of each odor sensor 90 is desorbed while the odor sensor 90 is vibrated at a predetermined frequency by the oscillation circuit 11, the amount of odor substance adsorbed to the adsorption film 92 decreases, and the resonant frequency of the quartz crystal oscillator of each odor sensor 90 changes. The detection circuit 12 outputs the resonant frequency detected by each odor sensor 90 to the determination unit 15. Hereinafter, the resonant frequency detected by each odor sensor 90 may be referred to as an output signal.

[0029] The communication unit 13 transmits and receives various information to and from an external device other than the odor measuring device 2, such as a data terminal 3, wirelessly or via wires.

[0030] The determination unit 15 calculates the amount of change in the resonant frequency of each odor sensor 90 when the odorant is desorbed based on the electrical signal of each odor sensor 90 input from the detection circuit 12, and measures the amount of the odorant from this calculation result. The determination unit 15 also determines the type and strength of the odor to be determined based on the amount of each odorant measured by each odor sensor 90. More specifically, the determination unit 15 determines the type and strength of the odor by referring to information stored in a database 34, which will be described later. The judgment results, such as the amount of change in resonant frequency of each odor sensor 90 calculated by the judgment unit 15, the amount of each measured odor substance, and the type of odor based on the amount of each odor substance, are output via the communication unit 13 to the data terminal 3 described later.

[0031] The control unit 14 controls the operation of the first pump 4A and the second pump 4B, the oscillation circuit 11 and the detection circuit 12, and the determination unit 15 in response to mode switching, which will be described later.

[0032] Fig. 2(A) is a schematic diagram for explaining an odor determination method in an odor determination system according to an embodiment of the present invention. Fig. 2(B) shows the change over time of the resonant frequency measured by the odor sensor 90 in a series of processes related to odor determination. As shown in Figures 2(A) and (B), a series of processes according to the odor determination method of the present invention includes a first mode, which is a step of supplying gas containing the odor to be determined, and a second mode, which is a measurement step. Hereinafter, the step of supplying gas containing the odor to be determined may be referred to as a supply step. In Figure 2(B), the period of the supply step is referred to as "supplying," and the period of the measurement step is referred to as "measuring."

[0033] The supplying step is a step of supplying the first gas 50 containing the odor to be determined to the adsorption film 92 of each odor sensor 90, thereby allowing each adsorption film 92 to adsorb an odor substance according to the type of adsorption film. In the supplying step, the odor sensor 90 is acclimated to the environment. Here, "acclimating to the environment" refers to supplying the first gas 50 containing the odor to be determined, which is the outside air, to the adsorption film 92 of the odor sensor 90, in other words, exposing the adsorption film 92 to the first gas 50 until the adsorption and desorption of the odor substance to each adsorption film 92 reaches a state of approximately equilibrium.

[0034] In the series of processes related to odor judgment, the measurement process is performed after the supply process. In the measurement process, the second gas 51 is supplied to the adsorption film 92 to desorb the odor substance adsorbed on the adsorption film 92, the resonant frequency, which is the output signal during this desorption process, is measured, and the amount of the odor substance is measured based on the amount of change in the resonant frequency, which is the output signal change amount.

[0035] The control unit 14 switches the inside of the storage chamber 20 between a first mode in which the inside of the storage chamber 20 serves as a processing environment for the supplying process and a second mode in which the inside of the storage chamber 20 serves as a processing environment for the measuring process.

[0036] In the first mode, which is the supply step, the control unit 14 operates the first pump 4A. As a result, as shown in FIG. 2(A), the first gas 50 is supplied into the storage chamber 20 via the first pump 4A. When the first gas 50 is supplied, each odor sensor 90 in the storage chamber 20 is exposed to the first gas 50, and the odor substance is adsorbed to the adsorption film 92 of each odor sensor 90. In the supply step, the resonant frequency decreases in proportion to the increase in the mass of the odor substance adsorbed to the adsorption film 92. The control unit 14 may control the oscillation circuit 11 and the detection circuit 12 to operate during the supply step.

[0037] In the second mode, which is the measurement step, the control unit 14 operates the second pump 4B. As a result, as shown in FIG. 2(A), the second gas 51 is supplied into the storage chamber 20 via the second pump 4B. When the second gas 51 is supplied, each odor sensor 90 in the storage chamber 20 is exposed to the second gas 51, and the odor substance adsorbed to the adsorption film 92 of each odor sensor 90 is desorbed. In the measurement step, the odor substance adsorbed to the adsorption film 92 is reduced by desorption of the odor substance from the adsorption film 92, and the resonant frequency increases in proportion to the decrease in the mass of the odor substance adsorbed to the adsorption film 92. During the measurement process, the control unit 14 controls the oscillation circuit 11 and the detection circuit 12 so that they operate. The control unit 14 acquires reference information used in odor determination from a database 34 (described later) via the communication unit 13 , and controls the information to be output to the determination unit 15 . The control unit 14 controls the output signal information of each odor sensor 90 acquired by the detection circuit 12 so as to be output to the determination unit 15. The output signal information of the odor sensor 90 is information on the resonance frequency associated with the desorption of an odor substance from the adsorption film 92. The control unit 14 also controls the humidity information detected by the humidity sensor 93 so as to be output to the determination unit 15. Furthermore, the control unit 14 controls the judgment unit 15 to measure the amount of odorous substance based on the information stored in the database 34, the detection information of the odor sensor 90 acquired by the detection circuit 12, and the humidity information detected by the humidity sensor 93.

[0038] (Data terminal) As shown in FIG. 1, the data terminal 3 includes a communication unit 31, a display unit 32, an input unit 33, and a database . The communication unit 31 transmits and receives various information to and from the odor measuring device 2 and other external devices wirelessly or via wires. The display unit 32 displays various information. The display unit 32 is a known display device. For example, the display unit 32 displays a resonance frequency change acquired from the odor measuring device 2 via the communication unit 31, a measurement result of the amount of a specified odor substance, and the like. The user can visually recognize the information displayed on the display unit 32. The input unit 33 is, for example, a keyboard, a touch panel, etc. A user may input and set, via the input unit 33, the time for supplying the gas to be measured, the measurement time, etc.

[0039] The database 34, which is a storage unit, may store information on changes in the output signals during the desorption process for each odor substance, which are measured in advance by each odor sensor 90 of the odor measuring device 2. The information is information on the change in the output signal when the odor sensor 90 is exposed to a first gas to adsorb the odor substance to the adsorption film 92, and then a second gas is supplied to the odor sensor 90 to desorb the odor substance adsorbed to the adsorption film 92. Hereinafter, the information on the change in the output signal when the odor substance is desorbed may be referred to as information related to desorption. The information on the desorption may be measured in advance by each of the multiple odor sensors 90 for each different humidity condition and each different odor substance. For each different humidity condition and each different odor substance, the type information of the odor substance and the change information of the output signal during the desorption process acquired by each of the multiple odor sensors 90 are associated with each other and stored in the database 34. The humidity is the humidity of the first gas and is measured by the humidity sensor 93.

[0040] The database 34 also stores information regarding the quantitative ratios of odor substances required for odor determination. 6(A) and (B) are radar charts showing the proportional relationship of the amount of change in resonant frequency detected by each odor sensor when gas emitted from oil A and oil B having different quantitative ratios of odor substances is measured using the odor determination method of this embodiment described later. The radar charts were created based on the maximum value of the amount of change in resonant frequency calculated based on the resonance frequency detected by each odor sensor 90. As shown in FIG. 6(A) and (B), the odor patterns differ due to the different quantitative ratios of odor substances. This can be used to determine the type of odor.

[0041] Furthermore, the database 34 may store information on changes in the output signal due to desorption of moisture from each odor sensor 90, which is measured in advance for each different humidity condition. Hereinafter, the information on changes in the output signal due to desorption of moisture may be referred to as information related to humidity. This information is information on changes in the output signal when the odor sensor 90 is exposed to a gas containing moisture that does not contain an odorant to adsorb the moisture to the adsorption film 92, and then the gas after the gas containing moisture that does not contain the odorant has passed through the filter 7 is supplied to the odor sensor 90 to desorb the moisture adsorbed to the adsorption film 92. The humidity in this case is the humidity of the gas containing moisture that does not contain an odorant and does not pass through the filter 7. The humidity of the gas containing moisture that does not contain an odorant is measured by the humidity sensor 93. The humidity information measured by the humidity sensor 93 and the information on changes in the output signal due to desorption of moisture acquired by each of the odor sensors 90 are stored in the database 34 in correspondence with each other.

[0042] Depending on the type, the adsorption film 92 may adsorb other substances (including odorous substances and odorless substances), moisture, etc. in addition to odorous substances, and the tendency to adsorb moisture also differs depending on the type of the adsorption film 92. The amount of moisture adsorbed also differs depending on the humidity of the gas. The change in resonant frequency measured when an odorant is desorbed from the adsorption film 92 to which the odorant has been adsorbed includes a change due to the desorption of the odorant adsorbed on the adsorption film 92 and a change due to the desorption of moisture. In this embodiment, the change in resonant frequency caused by the odorant can be calculated by removing the change in resonant frequency caused by moisture from the resonant frequency conversion actually detected by the odor sensor 90 during odor determination using the above-mentioned humidity-related information.

[0043] The configuration of the database 34 is not particularly limited, and is typically configured with a non-volatile storage device such as a semiconductor memory, a hard disk drive (HDD), etc. The database 34 is not limited to being installed indoors, and may be installed in other locations via a wired or wireless network. The database 34 may also be configured with a cloud server or the like. The database 34 is constructed, for example, by machine learning.

[0044] [How to identify odors] An embodiment of the odor determination method using the odor determination system 1 will be described below in comparison with a conventional example. 2, 3 and 4 are diagrams relating to the odor determination method of this embodiment. 7, 8 and 9 are diagrams relating to a conventional odor determination method. Fig. 2 corresponds to Fig. 7. Fig. 7(A) is a schematic diagram for explaining a conventional odor determination method. Fig. 7(B) shows the change over time in the resonant frequency measured by the odor sensor in a series of processes related to odor determination. Fig. 3 corresponds to Fig. 8. Fig. 3 is a flowchart of the odor determination method of the present embodiment. Fig. 8 is a flowchart of the odor determination method in the conventional example. FIG. 4 and FIG. 9 correspond to each other. FIG. 4(A) shows an example of the time spent in each process in the odor determination method of this embodiment. FIG. 4(B) shows the change over time in the amount of frequency change in each process in the odor determination method, calculated based on the measurement results of each odor sensor 90 of the odor determination system 1 shown in FIG. 1. FIG. 9(A) shows an example of the time spent in each process in a conventional odor determination method. FIG. 9(B) shows the change over time in the amount of frequency change in each process in the odor determination method, calculated based on the measurement results of each odor sensor of the odor determination system.

[0045] (Conventional odor determination method) A conventional odor determination method will be described with reference to FIGS. As shown in FIG. 7, the odor measuring device 102 used in the conventional odor determination method has the same basic configuration as the odor measuring device 2 of this embodiment, and includes a storage chamber 20, an odor sensor 90, a filter 7, a first pump 4A (not shown), and a second pump 4B (not shown). In the odor measuring device 102, odor determination is performed based on a change in the resonance frequency of the quartz oscillator of the odor sensor when an odor substance is adsorbed onto the adsorption film 92.

[0046] According to the flow chart of FIG. 8, a conventional odor determination method will be described with reference to FIG. 7 and FIG. When the odor determination process starts, the second pump 4B is operated to clean the odor sensor 90 (S11, cleaning step). By operating the second pump 4B, the outside air 150 passes through the filter 7 and becomes cleaning gas 151, which is supplied into the storage chamber 20. The outside air 150 is a gas containing the odor to be determined. In S11, the gas 151 after passing through the filter 7 is supplied into the storage chamber 20. The gas 151 that has passed through the filter 7 is a gas from which odor substances and moisture have been removed. By supplying the gas 151, the adsorption film 92 of the odor sensor 90 is cleaned. As a result, the odor substances adsorbed to the adsorption film 92 are desorbed and washed, and the adsorption film 92 returns to its initial state in which no odor substances are adsorbed thereon. This cleaning process lasts, for example, 20 minutes. Here, an example is given in which the gas 151 obtained through the filter 7 is used as the gas used in the cleaning process, but an inert gas or ozone may also be used as the gas for cleaning.

[0047] Next, the second pump 4B is stopped, the first pump 4A is operated, and the odor substance is measured by the odor sensor 90 (S12, measurement step). By operating the first pump 4A, gas (outside air) 150 containing the odor to be determined is supplied into the storage chamber 20. The adsorption film 92 of the odor sensor 90 is exposed to the gas 150 containing the odor to be determined. As a result, the odor substance is adsorbed onto the adsorption film 92 of the odor sensor 90. The change in resonant frequency accompanying this adsorption is measured by the odor sensor 90. The odor substance is determined based on the measurement result. The measurement process lasts, for example, one minute.

[0048] The process waits until the next measurement (S13), and determines whether or not to perform remeasurement (S14). Whether or not to perform remeasurement is determined by the control unit 14, for example, based on instruction information input by the user using the data terminal 3. If it is determined that remeasurement is to be performed (YES), the process returns to S11 and is repeated. If it is determined that remeasurement is not to be performed (NO), the series of processes related to odor determination ends.

[0049] As shown in FIG. 9A, the processing time required for each step depends on the volume of the inside of the accommodation chamber 20, and as an example, the cleaning step S11 takes 20 minutes, and the measurement step S12 takes 1 minute. In one conventional odor determination process, the total usage time of the first and second pumps is 21 minutes, and the usage time of the filter 7 is 20 minutes.

[0050] In this way, in the conventional odor determination method, odors are determined based on the change in resonance frequency caused by the adsorption of odor substances to the adsorption film 92 of the odor sensor 9, so the adsorption film 92 needs to be cleaned thoroughly for accurate measurement, and cleaning takes time. The time required for sufficient cleaning varies depending on the concentration of the odor substance, and it is difficult to determine how much time is needed for the cleaning process to achieve sufficient cleaning. For this reason, it is ideal that the adsorption film is in an initial state where no odor substances are adsorbed by the cleaning process in S11, which is performed before the measurement process, but it is difficult to clean it efficiently in terms of time. If cleaning is not performed sufficiently and odor substances remain on the adsorption film 92 at the start of the next measurement step, for example, as shown in FIG. 7(B), a difference b occurs between the value of the resonance frequency detected at the start time M2 of the next measurement step and the value of the resonance frequency detected at the start time M1 of the previous measurement step. It is assumed that the adsorption film 92 at the start time M1 of the previous measurement step is in an initial state in which odor substances are not adsorbed. In the next measurement step, the reference point for the start of the measurement step is the state where the difference b occurs between the previous reference point and the reference point, and the resonance frequency change is measured. As shown in the figure, in the adsorption step, which is the measurement step, the resonance frequency changes rapidly in a short time from the start of adsorption. For this reason, if odor substances remain on the adsorption film 92, that is, if the reference point for the start of measurement is shifted and the next measurement is started, accurate measurement cannot be performed, and it is difficult to perform stable and accurate measurement with the conventional odor determination method. Furthermore, for example, when measurements are performed continuously by repeating the cleaning process and the measurement process, it is difficult to set the time spent on the cleaning process as described above, and it is difficult to keep the state of the adsorption film 92 stable and the same at the start of each measurement process, so that conventional odor determination methods are not very suitable for continuous measurements.

[0051] Furthermore, in the conventional odor determination method, the adsorption film may not be cleaned sufficiently in the cleaning process, and moisture may remain on the adsorption film in addition to the odor substances that have not been completely desorbed. If moisture remains, the moisture remaining on the adsorption film will have a large effect on the output signal in the measurement process. Therefore, even if the odor is determined based on the change in the output signal of each odor sensor, it is difficult to make an accurate determination. Here, it is also possible to obtain information on the change in resonant frequency caused by humidity in advance, and subtract the change caused by humidity from the actual measurement value based on this information.However, if there is moisture remaining after being adsorbed in the previous measurement process, this moisture will have an effect, so even if the change caused by the humidity of the gas containing the odorant is subtracted from the actual measurement value, the change caused by the moisture remaining in the adsorption film cannot be subtracted, making it difficult to accurately calculate the change caused by the odorant, and difficult to accurately detect the intensity of the odor. As described above, with conventional odor determination methods, it was difficult to stably maintain the adsorption state in the adsorption film 92 at time M1 when the previous measurement process began and time M2 when the next measurement process began, making it difficult to perform accurate measurements.

[0052] (Odor Determination Method of the Present Embodiment) The odor determination method of this embodiment will be described with reference to FIGS. 2, 3, and 4. FIG. In the odor determination method using the odor measuring device 2 of this embodiment, a second gas is supplied to the adsorption film 92 on which an odor substance is adsorbed, and odor determination is performed based on the change in the resonant frequency of the quartz oscillator of the odor sensor when the odor substance is desorbed from the adsorption film 92.

[0053] According to the flowchart of FIG. 3, the odor determination method of the present embodiment will be described with reference to FIG. 2 and FIG. When the odor determination process starts, the first pump 4A is operated to supply the first gas 50 to the odor sensor 90 (S1, supply step). The first gas 50 is the outside air, which is the environment to be determined, and is a gas that contains the odor to be determined. By operating the first pump 4A, the first gas 50 containing the odor to be determined is supplied into the accommodation chamber 20, and the adsorption film 92 of the odor sensor 90 is exposed to the first gas 50. As a result, the odor substance is adsorbed onto the adsorption film 92 of the odor sensor 90. The supplying process lasts, for example, 20 minutes.

[0054] Next, the first pump 4A is stopped, the second pump 4B is operated, and a measurement is performed (S2, measurement step). By operating the second pump 4B, the first gas 50 passes through the filter 7 and becomes the second gas 51, which is supplied into the storage chamber 20. By supplying the second gas 51 to the odor sensor 90, the odor substance adsorbed on the adsorption film 92 of the odor sensor 90 is desorbed. The change in resonant frequency accompanying this desorption is measured. The amount of the odor substance is determined based on the measurement result. The measurement process lasts, for example, one minute.

[0055] The measurement process will now be described in more detail. In the measurement step, the resonant frequency information in the desorption process detected by each odor sensor 90 is output by the control unit 14 to the determination unit 15. In addition, the humidity information of the first gas 50 detected by the humidity sensor 93 is output by the control unit 14 to the determination unit 15. The determination unit 15, under the control of the control unit 14, acquires from the database 34 of the data terminal 3 information related to desorption and information related to humidity that correspond to the humidity information detected by the humidity sensor 93. The determination unit 15 refers to the information related to desorption acquired from the database 34 and determines the amount of odorous substance using the resonant frequency information detected by each odor sensor 90. Furthermore, the determination unit 15 judges the odor to be judged based on a radar chart such as that shown in Figs. 6(A) and (B) that is created based on the measurement results of each odor sensor 90. The determination unit 15 also judges the intensity of the odor based on the size (area) of the radar chart. The results of the determination made by the determination unit 15 and the detection results of each odor sensor 90 are transmitted to the data terminal 3, and the user can check these results on the display unit 32.

[0056] The process waits until the next measurement (S3), and determines whether or not to perform remeasurement (S4). The control unit 14 determines whether or not to perform remeasurement, for example, based on instruction information input by the user using the data terminal 3. If it is determined that remeasurement is to be performed (YES), the process returns to S11 and is repeated. If it is determined that remeasurement is not to be performed (NO), the series of processes related to odor determination ends.

[0057] 4(A), the processing time for each step depends on the volume of the storage chamber 20, but as an example, the supply step of S1 takes 20 minutes, and the measurement step of S2 takes 1 minute. Note that the time spent for each step is not limited to this. In one odor determination method of this embodiment, the total usage time of the first and second pumps is 21 minutes, and the usage time of the filter 7 is 1 minute. As described above, in the odor determination method of the present embodiment, the usage time of the filter 7 can be significantly shortened compared to the conventional method described above, and the frequency of filter replacement can be reduced, thereby improving work efficiency. For comparison, the volume of the container chamber 20 used in the measurement method of the above-mentioned conventional technology is the same as that of the container chamber 20 in this embodiment, the gas used is the same, and the processing conditions are the same.

[0058] Here, as shown in Fig. 2(B), in the supply process, the resonant frequency changes rapidly in a short time from the start of supply, then changes gradually, and then becomes saturated and constant. That is, in the latter half of the supply process, since the resonant frequency is almost constant, even if the next measurement is performed in a state in which the first gas is not sufficiently familiarized with the adsorption film 92, the difference a between the reference point at the time M1 when the previous measurement is started and the time M2 when the next measurement process is started can be made sufficiently small. That is, the adsorption state of the adsorption film 92 at the time M1 when the previous measurement is started and the time M2 when the next measurement process is started can always be in a state in which the odor substance is adsorbed in a nearly saturated state, and stable and accurate measurement can be performed. In addition, in this embodiment, the adsorption film 92 is almost saturated with odor substances at the start of the measurement, so even if odor substances remain on the adsorption film 92 at the end of the measurement process, it does not affect the next measurement process, and there is no need to thoroughly clean the adsorption film 92 for the next measurement process as in the past. This allows the filter to be used for a shorter period of time than in the past, and the frequency of filter replacement can be reduced.

[0059] Furthermore, for example, when measurements are performed by continuously repeating the supply process and measurement process, the adsorption state of the adsorption film 92 at the start of each measurement process can always be kept in a state in which the odorant is adsorbed in an almost saturated state. Here, in the conventional odor determination method described above, the measurement step is a step of adsorbing an odor substance to an adsorption film, and the measurement time is, for example, 1 minute. In the conventional odor determination method, when the cleaning step and the measurement step are continuously repeated, the adsorption time in the measurement step is short, so that, for example, if there is a bias in the concentration distribution of the odor substance in the outside air that is the measurement target, the amount of adsorption of the odor substance varies in each measurement, and the measured values ​​are likely to vary. Thus, in the conventional odor determination method, the measured values ​​may vary in each measurement, resulting in low reproducibility and making it difficult to measure the odor substance with high accuracy. In addition, it is possible to spend more time on the measurement step so as not to cause variation in the measured values, but since the time spent on the cleaning step is also long, the time required for one measurement process of the odor substance is long, and the work efficiency is reduced. In contrast, in this embodiment, the supply step is a step of adsorbing the odor substance to the adsorption film, and the supply time is, for example, 20 minutes. The time spent in the adsorption step corresponding to the supply step of this embodiment is sufficiently long compared to the time spent in the adsorption step corresponding to the measurement step in the conventional odor determination method. As a result, even if there is a bias in the concentration distribution of the odor in the outside air of the measurement target, for example, the influence of the bias in the concentration distribution of the odor can be suppressed to a small extent. Furthermore, since the state of the adsorption film at the start of each measurement is always in a state where the odor substance is adsorbed in a nearly saturated state, and each measurement is performed based on this state, it is possible to perform highly reproducible and highly accurate measurements stably and continuously. In addition, as shown in FIG. 2(B), in the measurement step corresponding to the desorption step, the resonant frequency behaves in such a way that it changes rapidly in a short time from the start of the measurement, so that the time spent in the measurement step can be set to be short. Therefore, it is possible to shorten the time required for one odor determination process, and it is possible to perform a highly accurate determination while improving the work efficiency. In this way, the odor determination method of this embodiment is also suitable for continuous measurements. In Fig. 2(B), the adsorption film 92 at the time M1 when the previous measurement process was started is in a state where the odor substance is adsorbed in a saturated state.

[0060] In addition, in the odor determination method of this embodiment, the adsorption film 92 at the start of measurement adsorbs not only the odor substances in the outside air, which is the first gas containing the odor to be determined, but also the moisture in the outside air. That is, in each measurement, the adsorption film at the start of measurement is always in a state in which the odor and humidity information of the outside air are almost reflected as is. Therefore, unlike the conventional odor determination method, it is not affected by the moisture that was not completely removed in the cleaning process and remained on the adsorption film, and the type of odor can be easily determined by referring to the desorption information, which corresponds to the humidity information of the first gas measured and acquired by the humidity sensor 93, and the amount of the odor substance can be calculated more accurately using the humidity information stored in the database 34. In this way, the odor determination method of the present embodiment is capable of performing humidity correction with greater accuracy than conventional odor determination methods.

[0061] (Odor determination based on the change in resonance frequency during desorption) Similar to odor determination based on the frequency change when an odor substance is adsorbed by an adsorption film, it was confirmed from the results shown in Figures 5 and 6 that odor determination can be performed based on the frequency change when an odor substance is desorbed from an adsorption film. In Figures 5 and 6, "Example" refers to an example in which the odor determination method of the present embodiment was used, and "Comparative Example" refers to an example in which the conventional odor determination method was used.

[0062] FIG. 5 shows the measurement results obtained using two types of oils, oil A and oil B, using the odor determination method of the present embodiment and the conventional odor determination method. Oil A and oil B have different quantitative ratios of odor substances. When odor determination is performed, the gases emitted from oil A and oil B are used as gases containing the odor substances to be determined. FIG. 5 shows the time-dependent change in frequency change calculated based on the measurement results of each of the 16 odor sensors 90. In FIG. 5, the graph of the embodiment is illustrated with the vertical axis inverted.

[0063] 6(A) and (B) are radar charts showing the proportional relationship between the amount of change in resonant frequency detected by each odor sensor 90 when gas emitted from different oils A and B is measured using the odor determination method of this embodiment. 6(C) and (D) are radar charts showing the proportional relationship of the amount of change in resonant frequency detected by each odor sensor 90 when gas emitted from different oils A and B is measured using the above-mentioned conventional odor determination method. In Fig. 6(C) and (D) as well, the radar charts are created based on the maximum value of the amount of change in resonant frequency calculated based on the resonant frequency detected by each odor sensor 90. In FIG. 6, the results of three measurements are shown for the comparative example, and the results of twenty measurements are shown for the example.

[0064] As shown in Figure 5, for both oil A and oil B, the same odor sensor reacts in both the examples and the comparative examples, and it was confirmed that odor judgment can be made based on the frequency change when an odorant is desorbed from the adsorption film, just as odor judgment can be made based on the frequency change when an odorant is adsorbed by the adsorption film. In addition, as shown in FIG. 6, in the radar chart, both oil A and oil B react with the same odor sensor in both the embodiment and the comparative example, and it was confirmed that odor judgment can be performed based on the frequency change when the odor substance is desorbed from the adsorption film, similar to the odor judgment based on the frequency change when the odor substance is adsorbed by the adsorption film. Furthermore, as shown in FIG. 6(A) and (B), radar charts of almost the same shape can be obtained even in multiple measurements, and it was confirmed that the odor judgment based on the frequency change when the odor substance is desorbed from the adsorption film is highly reproducible. Moreover, the embodiment tends to have less variation than the comparative example, and it was confirmed that the odor judgment method has higher reproducibility than the conventional odor judgment method.

[0065] As described above, in this embodiment, work efficiency is improved and odor determination can be performed with high accuracy.

[0066] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made, as a matter of course. In the above embodiment, the odor sensor is exemplified by a QCM, but is not limited thereto. Any sensor may be used as long as it has an adsorption film that can adsorb and desorb odor substances and outputs a signal corresponding to the adsorption of the odor substance. For example, a quartz crystal oscillator is exemplified as a vibration element used in the odor sensor, but other vibration elements such as ceramic oscillators, surface acoustic wave elements, cantilevers, and diaphragms that can determine physical changes such as weight increase and expansion stress increase due to odor substance adsorption in the adsorption film and convert them into electrical signals are also applicable. In addition, a semiconductor sensor that uses the resistance change due to odor substance adsorption in a semiconductor as an adsorption film, i.e., the output signal change, may be used as the odor sensor.

[0067] In addition, in the above embodiment, an example is given in which multiple odor sensors are provided, but a single odor sensor may be used. In this case, the present invention is applicable to measuring the amount or concentration of a known odor substance. Even in this case, the work efficiency is improved and odor determination can be performed with high accuracy.

[0068] In the above embodiment, the control unit 14 and the determination unit 15 are provided in the odor measurement device 2 equipped with the odor sensor 90, but the present invention is not limited to this. For example, at least one of the control unit 14 and the determination unit 15 may be provided in an external device other than the odor measurement device 2, such as a data terminal 3 or a cloud server. In the above embodiment, the database 34 is provided in the data terminal 3, but it may be provided in the odor measurement device 2 or the cloud server. The entire odor determination system 1 may include a sensor, a control unit, a determination unit, and a database.

[0069] In the above embodiment, the first pump 4A supplies the first gas to the storage chamber 20, and the second pump 4B supplies the second gas to the storage chamber 20, but a single pump may supply the first gas and the second gas to the storage chamber 20. In this case, for example, a supply flow path for the first gas and a supply flow path for the second gas, and a flow path switching valve for switching between these two supply flow paths are provided, and a filter for removing odorous substances and moisture is provided in the supply flow path for the second gas.

[0070] In addition, the humidity sensor 93 may be installed not only inside the storage chamber 20 but also outside the storage chamber 20, and humidity correction may be performed on the measurement data of each odor sensor based on the output of each humidity sensor installed inside and outside the storage chamber 20.

[0071] In the above embodiment, an example in which multiple odor sensors are provided has been given, but a single odor sensor may be used. For example, when the gas to be determined is known, the odor intensity can be determined from the output signal information during the desorption process using the odor sensor. [Explanation of symbols]

[0072] 1. Odor detection system 2. Odor measuring device 4A…First pump 4B…Second pump 7. Filter 14...Control section 15…Judgment section 16...Control device 50...First gas (gas containing the odor substance to be determined) 51...Second gas 90...Odor sensor (sensor) 92...Adsorption film

Claims

1. A sensor having an adsorption film that adsorbs an odorant and outputs a signal in response to the adsorption of the odorant; A chamber for accommodating the sensor; A first pump that supplies a first gas containing the odor substance to the storage chamber; a second pump that supplies a second gas to the storage chamber to desorb the odorous substance from the adsorption film; a control unit capable of sequentially executing a first mode in which the first gas is supplied to the storage chamber and the adsorption film is exposed to the first gas until the adsorption and desorption of the odor substance to the adsorption film reaches a substantially equilibrium state, and a second mode in which the second gas is supplied to the storage chamber; a determination unit that determines the odorous substance based on output signal information of the sensor during a desorption process in which the odorous substance adsorbed on the adsorption film in the first mode is desorbed from the adsorption film in the second mode; and An odor measuring device comprising:

2. The odor measuring device according to claim 1, The control unit executes the first mode for a longer period than the second mode.

3. The odor measuring device according to claim 1 or 2, The determination unit determines the odor substance by referring to information on changes in the output signal during the desorption process for each different odor substance, the information having been measured in advance by the sensor. Odor measuring device.

4. The odor measuring device according to claim 3, The change information of the output signal during the desorption process is measured in advance under different humidity conditions, The determination unit uses humidity information of the first gas acquired by a humidity sensor and refers to information on changes in an output signal during the desorption process to determine the odor substance. Odor measuring device.

5. The odor measuring device according to any one of claims 1 to 4, Further comprising a filter that adsorbs the odorous substance contained in the first gas; The second pump supplies the first gas that has passed through the filter to the storage chamber as the second gas. Odor measuring device.

6. The odor measuring device according to claim 5, The filter includes at least one of activated carbon, silica gel, zeolite, and allophane. Odor measuring device.

7. The odor measuring device according to any one of claims 1 to 6, The sensor includes a plurality of odor sensors having different detection sensitivities depending on the odor substance. Odor measuring device.

8. A control device for measuring an odorant based on output signal information of a sensor having an adsorption film that adsorbs the odorant, a control unit capable of sequentially executing a first mode in which a first gas containing the odorant is supplied to a storage chamber that contains the sensor, and the adsorption film is exposed to the first gas until the adsorption and desorption of the odorant to the adsorption film reaches a substantially equilibrium state, and a second mode in which a second gas is supplied to the storage chamber to desorb the odorant from the adsorption film; A determination unit that determines the odorous substance based on output signal information of the sensor during a desorption process in which the odorous substance adsorbed on the adsorption film in the first mode is desorbed from the adsorption film in the second mode; have Control device.

9. A first mode is executed in which a first gas containing an odorant is supplied to a sensor having an adsorption film that adsorbs an odorant and outputs a signal corresponding to the adsorption of the odorant, and the adsorption film is exposed to the first gas until the adsorption and desorption of the odorant to the adsorption film reach a substantially equilibrium state; A second mode is executed after the first mode in which a second gas that causes the odor substance to be desorbed from the adsorption film is supplied to the sensor to desorb the odor substance adsorbed on the adsorption film; The odor substance is measured based on output signal information of the sensor during a desorption process in which the odor substance adsorbed on the adsorption film in the first mode is desorbed from the adsorption film in the second mode. Odor determination method.

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