JP5205959B2 - Odor measuring device - Google Patents

Description

The present invention relates to an odor measurement apparatus, and more particularly to an odor measurement apparatus that continuously measures the intensity of a specific odor generated at a factory, a water intake, or the like.

Conventionally, the identification and evaluation of odors are generally performed using human sense of smell. However, since it is necessary to assume that the olfactory sensation changes depending on the individual difference of the person (panel) who actually smells and the physical condition of the day, in order to obtain measurement results with high accuracy, a certain number of panels must be secured. Also, sufficient consideration should be given to the environment of the test site. Therefore, it took enormous effort and time. Furthermore, even if done in this way, it is difficult to always make a definitive judgment based on a certain standard because human olfaction adapts to odor.

Therefore, in recent years, an odor measuring apparatus using an odor sensor, which is a kind of gas sensor having response characteristics with respect to an odor substance, has been developed (for example, see Patent Documents 1 and 2). In such an odor measurement apparatus, a measurement sample is obtained by performing various multivariate analysis processes such as cluster analysis and principal component analysis, and nonlinear analysis processes using a neural network, based on detection signals acquired by a plurality of odor sensors. The intensity of odor can be calculated.

Furthermore, an odor measuring device is disclosed that can determine the similarity to a plurality of standard odors based on detection signals acquired by a plurality of odor sensors for the odor of the measurement sample (see, for example, Patent Document 3). . In such an odor measuring apparatus, when a measurement sample is measured by, for example, m odor sensors, the intensity signal is output from each odor sensor, and therefore m measurement data are generated. These measurement data are mathematically represented by one point in an m-dimensional space (odor space). Therefore, when a plurality of samples are prepared so that the concentrations of the measurement samples are different from each other and measured, the point in the odor space moves in a certain direction as the concentration changes, so one line connecting the points. Can think. This single line has a specific orientation corresponding to the type of odor of the measurement sample. Therefore, if the measurement results of the reference sample having the reference odor are positioned and stored in the odor space in advance and the directions of the measurement result of the measurement sample and the measurement result of the reference sample are similar, On the other hand, if the directions are completely different, on the other hand, if the directions are completely different, the two are determined to be distant odors.

Specifically, in the odor space, when the measurement odor vector and the reference odor vector are formed as the measurement results of the measurement sample and the reference sample, respectively, the angle formed by the measurement odor vector and the reference odor vector is calculated. . As a result, the similarity of the odor of the measurement sample to the reference odor based on the calculated angle is set to 100% when the angle is 0 °, and is set to 0% when the angle is equal to or greater than a predetermined value. Thus, it is calculated by setting in the range of 0 to 100%. Further, an orthogonal projection of the measurement odor vector with respect to the reference odor vector is taken, and the intensity of the reference odor contained in the odor of the measurement sample is calculated based on the length of the orthogonal projection.
Japanese Patent Laid-Open No. 11-352088 JP 2002-22692 A JP 2003-315298 A

By the way, for the purpose of conservation measures for the surrounding environment at factories, water intakes, water discharge outlets, etc., for example, in factory buildings, factory premises or factory surroundings, water pipe headspace, etc. Measurements are made continuously. In addition, when there is an odor, it is necessary to specify the generation source and the generation cause.
However, for example, since a lot of odors other than the coke odor generated from the steel factory are mixed in the measurement sample actually collected from the steel factory, it must be configured in a complicated manner like the odor measuring apparatus described above. It was difficult to measure the strength of only the coke odor with sufficient accuracy. In addition, the responsiveness of the odor sensor is likely to change, and if it is not calibrated regularly, there is a case where measurement with sufficient accuracy cannot be performed.
Therefore, the present invention limits the quality of the odor to be measured, for example, by specializing in the use of measuring the strength of coke odor generated from one factory, it is generated from one factory while having a simple configuration. An object of the present invention is to provide an odor measuring apparatus capable of accurately and continuously measuring the intensity of coke odor.

That is, the odor measuring apparatus of the present invention includes m (m is an integer of 2 or more) odor sensors having different response characteristics, and an m-dimensional space formed to represent the measurement results of the m odor sensors. A reference sample measurement unit for positioning and storing measurement results of a reference sample having a reference odor, a measurement sample measurement unit for positioning measurement results obtained by continuously measuring the measurement sample in the m-dimensional space, and the stored A calculation unit that calculates the similarity between the reference odor of the reference sample and the odor of the measurement sample, and the intensity of the reference odor included in the odor of the measurement sample, based on the positional relationship between the measurement results of the reference sample and the measurement sample; An odor measuring device comprising a reference tank for storing the reference sample, wherein the reference sample measuring unit periodically measures the reference sample to store the reference sample to be stored. So that and updates the constant results.

According to the odor measuring apparatus of the present invention, the reference sample is stored in the reference tank. Then, by periodically measuring the reference sample, the reference odor vector is updated and stored in the m-dimensional space.
The “reference odor” means, for example, the odor of the measurement object or the odor that can be identified.
The “reference sample” refers to a sample collected in advance at a measurement location where the measurement sample is measured, or a sample adjusted to generate a reference odor.

According to the odor measuring apparatus of the present invention, even if the responsiveness of the odor sensor changes, the reference odor vector is stored again. Therefore, the intensity of the reference odor contained in the odor of the measurement sample is always measured with sufficient accuracy. be able to.

(Means and effects for solving other problems)
In addition, the odor measuring apparatus of the present invention further includes a standard tank for storing a standard sample having no reference odor, and the reference sample measuring unit has a mixture ratio of the reference sample and the standard sample changed. The measurement result of the reference sample may be stored by measuring each.
According to the odor measuring apparatus of the present invention, the standard sample is further stored in the standard tank. Periodically, a plurality of samples (for example, four levels of no dilution, 1/3 dilution, 1/10 dilution, standard sample only) are prepared and measured so that the concentrations of the reference samples are different. Thus, the reference odor vector is updated and stored in the m-dimensional space. Thereby, even if the responsiveness of the odor sensor changes, the reference odor vector is stored again, so that the intensity of the reference odor contained in the odor of the measurement sample can always be measured with sufficient accuracy.
The “standard sample” refers to, for example, an inert gas such as nitrogen gas or pure air gas, or a sample collected in advance when a reference odor is not generated at the measurement location where the measurement sample is measured. Say.

Furthermore, in the odor measuring apparatus of the present invention, the reference sample may be collected in advance at a measurement place where the measurement sample is measured.
In the odor measurement apparatus of the present invention, the reference sample measurement unit creates a reference odor vector from the measurement result of the reference sample, and the measurement sample measurement unit creates a measurement odor vector from the measurement result of the measurement sample. And the calculation unit calculates the similarity between the reference odor of the reference sample and the odor of the measurement sample based on an angle formed by the reference odor vector and the measurement odor vector, and the measurement odor vector with respect to the reference odor vector. The intensity of the reference odor contained in the odor of the measurement sample may be calculated based on the length of the orthogonal projection.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment, It cannot be overemphasized that various aspects are included in the range which does not deviate from the meaning of this invention.

FIG. 1 is a block diagram showing a configuration of an odor measuring apparatus according to an embodiment of the present invention. Hereinafter, a case where coke odor generated from a steel factory is continuously measured as an odor to be measured will be described.
The odor measuring apparatus includes a suction port 1 for sucking a measurement sample, a preprocessing unit (collecting tube) 2 for performing preprocessing, a sensor cell 3 having four odor sensors 31 to 34 having different response characteristics, and a sensor cell. 3, a pump 4 for drawing a sample, a reference tank 10 for storing the reference sample, a standard tank 11 (a container, a cylinder, etc.) for storing the standard sample, a three-way valve 14 for switching the sample to be taken into the sensor cell 3, and an odor. A control unit 5 that analyzes the detection signals from the sensors 31 to 34 and controls the operation of the entire apparatus, a display unit 6 that displays an output from the control unit 5 on a display screen, and an operation unit 8 having a keyboard. It consists of.

The reference sample having the reference odor is previously collected at the measurement place where the measurement sample is measured. In the case of gas at room temperature, the reference sample is sealed in a gas cylinder as a reference tank 10 (container, cylinder, etc.) The quantity is taken out and used. Further, in the case of liquid, it is put in a glass container or the like as the reference tank 10 and used by being kept at a predetermined temperature or being bubbled with nitrogen gas or the like. Further, in the case of a solid, it is put in a glass container or the like as the reference tank 10 and used at a predetermined temperature.
On the other hand, as a standard sample having no reference odor, for example, an inert gas such as nitrogen gas or pure air gas is used. The standard sample is sealed in a gas cylinder or the like as the standard tank 11 and a certain amount is taken out and used. . The standard sample may also be a sample collected in advance when the reference odor is not generated at the measurement location where the measurement sample is measured.

For example, the suction port 1 is arranged on the boundary line of an adjacent site of a steel factory, and collects a measurement sample.
The pretreatment unit (collection tube) 2 performs removal of moisture contained in the sample, concentration / dilution of the sample, removal of interfering gas, and the like. Therefore, in the pre-processing unit 2, for example, by diluting the reference sample with the standard sample, the concentration of the reference sample can be adjusted in multiple stages (for example, no dilution, 1/3 dilution, 1/10 dilution, only the standard sample). It is possible to prepare a sample that has been changed to four stages).

The odor sensors 31 to 34 are oxide semiconductor sensors each having different response characteristics in which the electric resistance value changes depending on the odor substance. However, the odor sensors 31 to 34 are gasses on the surfaces of the conductive polymer sensor, the crystal resonator, and the SAW device. A sensor using another detection method such as a sensor having an adsorption film may be used. Further, the number of odor sensors is not particularly limited. When a sample comes into contact with such odor sensors 31 to 34, detection signals are output from the odor sensors 31 to 34 to the control unit 5 in parallel.

The control unit 5 is configured with a personal computer as the center, and by executing a predetermined program on the computer, the sample processing unit 20, the reference sample measurement unit 21, the measurement sample measurement unit 22, the calculation unit 23, It functions as the determination unit 24 and the image display unit 25. The control unit 5 is connected to a storage device (memory, HDD, etc.) 7 for storing data.

The sample processing unit 20 controls the drawing of the sample into the sensor cell 3 by operating the pump 4 and switching the three-way valve 14 based on an output signal from the operation unit 8.
For example, when an output signal (calibration signal) for performing a setting operation for use of a reference odor is received, a sample obtained by diluting a reference sample with a standard sample is prepared in the preprocessing unit 2 by switching the three-way valve 14, and a sensor cell Will be drawn to 3. At this time, for example, the reference sample concentration is changed to four levels of undiluted, diluted to 1/3, diluted to 1/10, and only the standard sample, and sequentially drawn into the sensor cell 3. On the other hand, when the output signal (calibration signal or end signal) from the operation unit 8 is not received, the measurement sample is drawn into the sensor cell 3 from the suction port 1 by switching the three-way valve 14.

The reference sample measurement unit 21 converts a sample obtained by changing the mixing ratio of the reference sample and the standard sample into a plurality of stages into a four-dimensional space (odor space) formed by the four odor sensors according to the measurement results. Control for creating a reference odor vector S1 and storing it in the storage device 7 is performed.
Specifically, four measurement data DS1, DS2, DS3, and DS4 are obtained from the odor sensors 31 to 34 for one sample. Here, considering the four-dimensional space (odor space) formed by using the four measurement data obtained from the odor sensors 31 to 34 as axes in different directions, the four measurement data DS1, DS2, DS3, DS4. Can be represented by one point (DS1, DS2, DS3, DS4) in the odor space. As a result, the measurement results obtained by measuring the sample in which the concentration of the reference sample was changed to four levels of undiluted, diluted to 1/3, diluted to 1/10, and only the standard sample are shown in the odor space. Since the point shifts in a specific direction, this is regarded as the reference odor vector S1 in the odor space.
Here, since it is difficult to illustrate a four-dimensional space (odor space), here, in order to facilitate understanding, it is formed by two measurement data DS1 and DS2 obtained from two odor sensors 31 and 32. Consider a simplified two-dimensional space. As shown in FIG. 2, in the two-dimensional space, two measurement data DS1 and DS2 for the undiluted sample of the reference sample are represented by one measurement point P1. The measurement points for the sample diluted as described above are represented as P2, P3, and P4, respectively. Thus, the reference odor vector S1 corresponding to the reference odor of the reference sample can be drawn by connecting P4, P3, P2, and P1 in a straight line. In some cases, a straight line may be used instead of a straight line. In this case, a straight line may be determined by a simple approximation calculation.

The measurement sample measurement unit 22 performs control to create a measurement odor vector SX in a four-dimensional space (odor space) based on the measurement result of the measurement sample.
Specifically, as described above, four measurement data DS1, DS2, DS3, and DS4 are obtained from the odor sensors 31 to 34 for one sample. The four measurement data DS1, DS2, DS3, DS4 can be represented by one point (DS1, DS2, DS3, DS4) in the odor space. Thereby, what connected this point and the origin P4 memorize | stored in the memory | storage device 7 is taken as the odor vector SX in the measurement in odor space.
Therefore, as shown in FIG. 2, the two measurement data DS1 and DS2 for the measurement sample are represented by one measurement point PX in the two-dimensional space, as described above. Thereby, by connecting P4 and PX in a straight line, the measurement odor vector SX corresponding to the odor of the measurement sample can be drawn.

The calculation unit 23 calculates the similarity α between the reference odor of the reference sample and the odor of the measurement sample based on the angle θ formed by the reference odor vector S1 and the measurement odor vector SX, and at the measurement of the reference odor vector S1. Control is performed by taking an orthogonal projection of the vector SX and calculating a reference odor intensity (odor index equivalent value) T included in the odor of the measurement sample based on the length L of the orthogonal projection.
Here, when the direction of the measurement odor vector SX is similar to the direction of the reference odor vector S1, it can be determined that the odor of the measurement sample is a kind of odor similar to the reference odor. If the directions are completely different, it can be determined that the odor is a distant odor. Therefore, as an index for determining the similarity between the measurement odor vector SX and the reference odor vector S1, the reference odor of the reference sample and the odor of the measurement sample are determined based on the angle θ between the reference odor vector S1 and the measurement odor vector SX. The similarity α is calculated.
Therefore, as shown in FIG. 3, when the angle θ formed by the reference odor vector S1 and the measurement odor vector SX is 0 °, the similarity α is 100%, and the angle θ is equal to or greater than the threshold θth. Is set to the storage device 7 as a function of the relationship between the angle θ and the similarity α so that the similarity α is determined to be 0%. Thus, the odor similarity α of the measurement sample with respect to the reference odor is represented by a numerical value of 0 to 100%.

Further, the reference odor intensity (odor index equivalent value) T included in the odor of the measurement sample is determined as follows. As shown in FIG. 2, an orthogonal projection of the measurement odor vector Sx to the reference odor vector S1 is taken, and based on the length L of the orthogonal projection, a reference odor intensity T included in the odor of the measurement sample is calculated.
Therefore, for example, with respect to the reference sample, the odor index adopted in the malodor prevention method (three-point comparison odor bag method) is previously measured and set in the storage device 7. Thereby, the odor index of the reference sample corresponding to the length L of the orthogonal projection is calculated as the intensity (odor index equivalent value) T of the reference odor contained in the odor of the measurement sample.
The odor index refers to an index that expresses the odor intensity by diluting magnification when the sample is diluted to odorless. For example, if the sample is diluted 1000 times to become odorless, the odor concentration is 1000. And the odor index is 30 according to the following equation (1).
Odor index = 10 × log ₁₀ (odor concentration) (1)

The determination unit 24 outputs an abnormal signal to the display unit 6 when the reference odor intensity (odor index equivalent value) T included in the odor of the measurement sample is equal to or greater than the intensity threshold value Tth stored in the storage device 7. The control which performs is performed.
The image display unit 25 performs control to display outputs from the calculation unit 23 and the determination unit 24 on a display screen. For example, numerical image display of the similarity α and the intensity (odor index equivalent value) T is performed. Further, when an abnormal signal is received from the determination unit 24, an image is displayed by changing the color of the numerical value of the intensity (odor index equivalent value) T.

Next, a method for using the odor measuring apparatus will be described. Here, a case where coke odor generated from a steel factory is measured as an odor to be measured will be described. FIG. 4 is a flowchart for explaining an example of a method of using the odor measuring apparatus.
(1) Preliminary setting operation of odor measuring device First, in the process of step S101, the odor index adopted in the malodor control method (three-point comparison odor bag method) with respect to a reference sample having a coke odor collected at a steel factory. Is measured and set in the storage device 7, and the intensity threshold Tth is set in the storage device 7.

Next, in the process of step S102, when the angle θ formed by the reference odor vector S1 and the measurement odor vector SX is 0 °, the similarity α is 100%, and the angle θ is equal to or greater than the threshold θth. In some cases, the relationship between the angle θ and the similarity α is set as a function in the storage device so as to determine that the similarity α is 0% (see FIG. 3).
Next, in the process of step S <b> 103, a reference sample having a coke odor is stored in the reference tank 10, and an inert gas (standard sample) is stored in the standard tank 11.

(2) Setting operation of use of odor measuring device Next, in the processing of step S104, the sample processing unit 20 switches the three-way valve 14 to dilute the reference sample with an inert gas (standard sample) in the preprocessing unit 2. The prepared sample is prepared and drawn into the sensor cell 3.
Next, in the process of step S105, the reference sample measuring unit 21 has four odors based on the measurement results obtained by measuring the samples in which the mixing ratio of the reference sample and the inert gas (standard sample) is changed in a plurality of stages. A reference odor vector S1 is created in a four-dimensional space (odor space) formed by the sensor and stored in the storage device 7. At this time, if the reference odor vector S1 stored in the storage device 7 exists, the reference odor vector S1 is updated and stored.

(3) Measurement Operation of Odor Measuring Device Next, in the process of step S106, the sample processing unit 20 switches the three-way valve 14 to draw the measurement sample from the suction port 1 into the sensor cell 3.
Next, in the process of step S107, the measurement sample measurement unit 22 creates a measurement odor vector SX in a four-dimensional space (odor space) based on the measurement result of the measurement sample.

Next, in the processing of step S108, the calculation unit 23 calculates the similarity α between the coke odor of the reference sample and the odor of the measurement sample based on the angle θ formed by the reference odor vector S1 and the measurement odor vector SX. At the same time, an orthogonal projection of the measurement odor vector SX with respect to the reference odor vector S1 is taken, and based on the length L of the orthogonal projection, the intensity (corresponding to the odor index) T of the coke odor contained in the odor of the measurement sample is calculated (FIG. 2).
Next, in the process of step S109, the determination unit 24 determines whether or not the intensity of the coke odor included in the odor of the measurement sample (the odor index equivalent value) T is equal to or greater than the intensity threshold Tth stored in the storage device 7. Determine whether. If it is determined that the intensity T of the coke odor contained in the odor of the measurement sample is equal to or greater than the threshold value Tth, the determination unit 24 outputs an abnormal signal to the display unit 6 in the process of step S110.

On the other hand, when it is determined that the intensity T of the coke odor contained in the odor of the measurement sample is not equal to or greater than the threshold value Tth, or when the process of step S110 is completed, in the process of step S111, the image display unit 25 calculates the calculation unit. 23 and the output from the determination unit 24 are displayed on the display screen.
Next, in the process of step S <b> 112, the sample processing unit 20 determines the type of the output signal received from the operation unit 8. When the output signal for performing the use setting operation of the coke odor is received, the process returns to the process of step S104. Further, when an output signal for ending the measurement work of the odor measuring apparatus is received, this flowchart is ended. Furthermore, when an output signal is not received from the operation part 8, it returns to the process of step S106. That is, until the time when the output signal is received from the operation unit 8, the processes in steps S <b> 106 to S <b> 112 are repeatedly executed to measure the coke odor generated from the steel factory.

As described above, according to the odor measuring apparatus of the present invention, the reference sample having the coke odor collected at the steel factory is stored in the reference tank 10 and the inert gas (standard sample) is stored in the standard tank 11. Can do. And periodically, prepare multiple samples (4 levels, such as no dilution, 1/3 dilution, 1/10 dilution, inert gas (standard sample) only) so that the concentration of the reference sample is different. By measuring each, the reference odor vector S1 can be updated and stored in the four-dimensional space. Therefore, even if the responsiveness of the odor sensors 31 to 34 changes, the reference odor vector S1 is stored again, so that the strength of the coke odor (odor index equivalent value) T contained in the odor of the measurement sample is always sufficiently accurate. Can be measured more.

(Other embodiments)
(1) In the odor measuring apparatus described above, a measurement odor vector is generated in a four-dimensional space (odor space) formed by four odor sensors based on only the measurement result obtained by measuring the measurement sample without diluting it with the preprocessing unit 2. The SX is created, but a four-dimensional space (scent space) formed by four odor sensors based on the measurement results obtained by measuring each sample obtained by changing the mixing ratio of the measurement sample and the standard sample in multiple stages. Alternatively, the measurement odor vector SX may be created.
(2) In the odor measuring apparatus described above, when the output signal (calibration signal) for performing the use setting operation of the reference odor is received, the reference sample is diluted with the standard sample in the preprocessing unit 2 by switching the three-way valve 14. The sample was prepared and pulled into the sensor cell 3. However, the three-way valve was automatically activated after one hour without receiving an output signal (calibration signal) for setting the use of the reference odor. It is also possible to prepare a sample obtained by diluting the reference sample with the standard sample in the pre-processing unit by switching to the sensor cell and pull it into the sensor cell.

The vector is usually a straight line, but the vector in the present invention should be interpreted to include a curve obtained by changing the concentration of the same odor.

INDUSTRIAL APPLICATION This invention can be utilized for the smell measuring apparatus which measures the intensity | strength of the specific odor which generate | occur | produces in a factory, a water intake, etc.

It is a block diagram which shows the structure of the odor measuring apparatus which is one Embodiment of this invention. It is explanatory drawing which shows the relationship between the reference | standard smell vector S1 and the measurement smell vector SX. It is a figure which shows the relationship between angle (theta) and similarity degree (alpha). It is a flowchart for demonstrating an example of the usage method of an odor measuring apparatus.

Explanation of symbols

10: Reference tank 21: Reference sample measurement unit 22: Measurement sample measurement unit 23: Calculation units 31 to 34: Odor sensor

Claims (4)

M (where m is an integer of 2 or more) odor sensors having different response characteristics;
A reference sample measurement unit for positioning and storing a measurement result of a reference sample having a reference odor in an m-dimensional space formed to represent the measurement results of the m odor sensors;
A measurement sample measurement unit that positions measurement results obtained by continuously measuring measurement samples in the m-dimensional space;
Based on the positional relationship of the measurement results of the stored reference sample and measurement sample, the similarity between the reference odor of the reference sample and the odor of the measurement sample and the intensity of the reference odor included in the odor of the measurement sample are calculated. A calculating unit to
An odor measuring device comprising a reference tank for storing the reference sample,
The reference sample measurement unit updates the measurement result of the reference sample to be stored by periodically measuring the reference sample. In addition, it has a standard tank for storing standard samples that do not have a standard odor,
2. The odor according to claim 1, wherein the reference sample measurement unit stores the measurement result of the reference sample by measuring each of the mixed samples having different mixing ratios of the reference sample and the standard sample. measuring device. The odor measurement apparatus according to claim 1 or 2, wherein the reference sample is collected in advance at a measurement place where the measurement sample is measured. The reference sample measurement unit creates a reference odor vector from the measurement result of the reference sample,
The measurement sample measurement unit creates a measurement odor vector from the measurement result of the measurement sample, and
The calculation unit calculates the similarity between the reference odor of the reference sample and the odor of the measurement sample based on the angle formed by the reference odor vector and the measurement odor vector,
The intensity of the reference odor contained in the odor of the measurement sample is calculated based on the orthographic projection of the measurement odor vector with respect to the reference odor vector, and based on the length of the orthographic projection. The odor measuring apparatus according to claim 1.

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