Calibration method for measurement temperature of concentration measurement device and concentration measurement device

Abstract

Provided is a concentration measurement device that measures the concentration of a sample by absorptiometry, the concentration measurement device being capable of performing temperature measurement in a shorter amount of time than conventional concentration measurement devices.　A concentration measurement device 1 comprises a sample temperature sensor 13 that measures the temperature of samples, optical sensors 141, 142 that measure the transmittance of samples, an environmental temperature sensor 13 that measures the environmental temperature, a storage unit 12 that stores second correlation information between first difference information for the value of the environmental temperature and the value of the temperature of a calibration sample measured by the concentration measurement device 1 and second difference information for the measured value of the temperature of the calibration sample and a theoretical temperature based on first correlation information between the temperature and the transmittance of the calibration sample with respect to the value of the transmittance of the calibration sample measured by the concentration measurement device 1, and a temperature calibration unit 11 that acquires difference information for the measured value of the temperature of a sample to be measured and the measured value of the environmental temperature and calibrates the temperature measurement value for the sample to be measured using calibration temperature information based on the second correlation information with respect to the acquired difference information.

Description

Method for calibrating temperature measured by concentration measuring device, and concentration measuring device

[0001] The present invention relates to a concentration measurement device that performs concentration measurement based on measurement of temperature and transmittance or absorbance for a sample having a correlation between temperature, transmittance or absorbance, and concentration, and a method for calibrating the measurement temperature in the concentration measurement device.

[0002] In medical settings, medical instruments used in surgeries and other procedures are cleaned, sterilized, and reused. For patient safety, endoscopes must be cleaned using a specified concentration of high-level disinfectant after wiping off visible dirt (see "Guidelines for Standardization of Cleaning and Disinfection of Gastrointestinal Endoscopes" published by the Japan Gastroenterological Endoscopy Society and the Japanese Association of Infectious Diseases). Because disinfectants used for cleaning are relatively expensive, they are typically used repeatedly a certain number of times or for a certain period of time, and their concentration is measured before use to ensure they meet the specified concentration. Patent Document 1 discloses technology related to a device that uses absorptiometry to measure the concentration of such disinfectants.

[0003] Japanese Patent Application Laid-Open No. 2005-69969

[0004] Disinfectants such as glutaral and phthalal aqueous solutions have a correlation between temperature, transmittance (or absorbance), and concentration. Therefore, in order to measure the concentration based on transmittance using absorptiometry, it is necessary to also measure the temperature (or to measure under specified temperature conditions). Here, as described in Patent Document 1, the concentration measurement of a disinfectant using a concentration measurement device using absorptiometry is performed on a disinfectant (sample) contained in an optical cell. However, accurately measuring the temperature of the liquid in such a cell is not necessarily easy. Simply put, it is possible to measure the temperature by directly contacting a contact-type temperature sensor, such as a thermocouple, with the disinfectant in the optical cell. However, in the case of a contact-type sensor, if there is a temperature difference between the disinfectant and the temperature sensor, the temperature sensor itself will be affected by its heat capacity. Based on considerations such as ease of use and avoiding waste of disinfectant, the amount of disinfectant in the optical cell is limited to a few cc, and the impact of the temperature sensor contact may not be negligible. To solve these problems, it is conceivable to use a non-contact temperature sensor. However, when a non-contact radiation sensor is used, the radiation temperature from the wall surface of the optical cell is measured, and if there is a temperature difference between the optical cell and the disinfectant, the temperature of the disinfectant may not be measured correctly. Conventionally, in order to prevent or reduce these problems, concentration measurement (temperature measurement for this purpose) is performed after waiting until there is no temperature difference between the disinfectant and the concentration measurement device (such as the optical cell) (by leaving them at ambient temperature to achieve thermal equilibrium). However, this operation is cumbersome, and there is a demand for concentration measurement in a shorter time.

[0005] In view of the above, an object of the present invention is to provide a concentration measurement device (and a method for calibrating the measurement temperature) that measures the concentration of a sample by absorptiometry and that enables temperature measurement to be performed relatively accurately and in a short time.

[0006] (Configuration 1) A method for calibrating a measurement temperature in a concentration measurement device that performs concentration measurement based on measuring the temperature and transmittance or absorbance of a sample having a correlation between the temperature, transmittance or absorbance, and concentration, comprising the steps of: acquiring first correlation information between the temperature and transmittance or absorbance based on a sample having a known concentration; measuring values ​​over time for the temperature, transmittance or absorbance, and environmental temperature of the sample having a known concentration using a concentration measurement device that is equipped with a sample temperature sensor, an optical sensor, and an environmental temperature sensor; and acquiring first difference information between the measured value of the environmental temperature and the measured value of the sample temperature, and measuring the transmittance or absorbance. A method for calibrating the measured temperature of a concentration measuring device, comprising: a step of acquiring second correlation information between a theoretical temperature based on the first correlation information for the measured value of luminous intensity and second difference information between the measured value of the temperature of the sample whose concentration is known; a step of acquiring difference information between the measured value of the temperature of the sample by the sample temperature sensor and the measured value of the environmental temperature by the environmental temperature sensor in measuring the temperature of the sample whose concentration is unknown, and acquiring calibration temperature information based on the second correlation information for the difference information; and a step of calibrating the measured value of the temperature of the sample using the calibration temperature information.

[0007] (Configuration 2) A method for calibrating the measured temperature of a concentration measuring device described in Configuration 1, wherein, in acquiring the second correlation information, positive second correlation information and negative second correlation information are acquired depending on whether the difference between the measured environmental temperature and the measured sample temperature when measuring the concentration of the sample whose concentration is known is positive or negative, and the calibration temperature information is acquired based on either the positive second correlation information or the negative second correlation information depending on whether the difference between the measured environmental temperature and the measured sample temperature when measuring the sample whose concentration is unknown is positive or negative.

[0008] (Configuration 3) A method for calibrating the measured temperature of a concentration measuring device described in Configuration 1 or 2, wherein an error is detected if the absolute value of the difference between the measured environmental temperature and the measured sample temperature when measuring the concentration of a sample whose concentration is unknown is greater than the absolute value of the maximum difference between the measured environmental temperature and the measured sample temperature when measuring a sample whose concentration is known.

[0009] (Configuration 4) A concentration measurement device that performs concentration measurements based on temperature and transmittance or absorbance measurements for a sample having a correlation between temperature, transmittance or absorbance, and concentration, comprising: a sample temperature sensor for measuring the temperature of the sample; an optical sensor for measuring the transmittance or absorbance of the sample; an environmental temperature sensor for measuring the environmental temperature; a memory unit that stores first difference information between the environmental temperature measurement value obtained by the concentration measurement device and the temperature measurement value of a calibration sample; and second difference information between a theoretical temperature based on the first correlation information between the temperature and transmittance or absorbance of the calibration sample and the measured temperature of the calibration sample for the measured value of the transmittance or absorbance of the calibration sample obtained by the concentration measurement device; and a temperature calibration unit that acquires difference information between the sample temperature measurement value obtained by the sample temperature sensor and the environmental temperature measurement value obtained by the environmental temperature sensor, and calibrates the measurement value obtained by the sample temperature sensor using calibration temperature information based on the second correlation information for the difference information.

[0010] (Configuration 5) The concentration measuring device according to Configuration 4, wherein the second correlation information includes positive second correlation information and negative second correlation information according to whether the difference between the measured environmental temperature and the measured sample temperature at the time of measuring the concentration of the calibration sample is positive or negative, and the calibration temperature information is acquired based on either the positive second correlation information or the negative second correlation information according to whether the difference between the measured environmental temperature by the environmental temperature sensor and the measured sample temperature by the sample temperature sensor is positive or negative.

[0011] (Configuration 6) A concentration measuring device according to configuration 4 or 5, wherein error processing is performed when the absolute value of the difference between the environmental temperature measured by the environmental temperature sensor and the sample temperature measured by the sample temperature sensor exceeds a predetermined threshold value.

[0012] (Configuration 7) A concentration measuring device according to configuration 4 or 5, wherein, when the absolute value of the difference between the environmental temperature measured by the environmental temperature sensor and the sample temperature measured by the sample temperature sensor exceeds a predetermined threshold, a process of waiting until the difference becomes equal to or less than the threshold is performed.

[0013] According to the present invention, it is possible to provide a concentration measurement device (and a method for calibrating the measurement temperature) that measures the concentration of a sample by absorptiometry and that is capable of performing temperature measurement relatively accurately and in a short time.

[0014] A block diagram showing an outline of the configuration of a concentration measurement device according to an embodiment of the present invention. A flowchart showing an outline of a concentration measurement method (mainly a method for calibrating the measured temperature) according to an embodiment of the present invention. A graph showing an example of the correlation (first correlation information) between temperature and transmittance, created based on a disinfectant solution with a known concentration. The concentration measurement device measures the temperature of a disinfectant solution with a known concentration and the environmental temperature over time, and calculates T ｓｕｂ１ An example of a graph in which the transmittance of a disinfectant solution with a known concentration is measured over time using a concentration measuring device, and the measured transmittance is converted into a theoretical temperature based on the first correlation information and graphed. T is the difference between the temperature of the disinfectant solution with a known concentration and the theoretical temperature. ｓｕｂ２ An example of graphing ｓｕｂ１ and T ｓｕｂ２ Graph showing an example of the correlation (second correlation information) of the graph of FIG. 7. Graph showing the results of a demonstration experiment of the concentration measurement device of the embodiment. Flowchart showing another example of part of the processing operation of the concentration measurement method of the embodiment (mainly the method of calibrating the measurement temperature).

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the following embodiment is one form for realizing the present invention, and is not intended to limit the scope of the present invention.

[0016] 1 is a block diagram showing an outline of the configuration of a concentration measuring device according to an embodiment of the present invention. The concentration measuring device 1 of this embodiment is a concentration measuring device that measures the temperature and transmittance or absorbance of a disinfectant solution, such as a glutaral aqueous solution or a phtharal aqueous solution, which has a correlation between temperature, transmittance or absorbance, and concentration, based on measurement of the temperature and transmittance or absorbance, and includes an optical cell OC that contains the disinfectant solution, a radiation temperature sensor 13 that functions as both a sample temperature sensor for measuring the temperature of the disinfectant solution and an environmental temperature sensor for measuring the environmental temperature, a light-emitting unit 141 and a light-receiving unit 142 that are optical sensors for measuring the transmittance or absorbance of the disinfectant solution, a memory unit 12 in which various data, programs, etc. required for the operation of the device are permanently or temporarily stored, an input unit 15 that has input means such as operation buttons and serves as a user interface, an output unit 16 that has output means such as a screen and indicators and serves as a user interface, and a control / calculation unit 11 that controls each unit of the device, performs various calculations, and also functions as a temperature calibration unit as described below. With regard to the above reference to "transmittance or absorbance," absorbance is the logarithm of the reciprocal of transmittance, and the difference between transmittance and absorbance does not bring about a conceptual difference in the application of the present invention (for example, when treated as absorbance, a conversion based on the above relational expression can be performed), and therefore, hereinafter, it will be simply referred to as "transmittance."

[0017] The optical cell OC is a container made of a material that transmits the light emitted by the light-emitting unit 141, and contains about several cc of disinfectant. The optical cell OC is detachable from the concentration measuring device 1, and is basically a single-use (disposable) component.

[0018] The radiation temperature sensor 13 is positioned facing the area of ​​the optical cell OC attached to the concentration measuring device 1 where the disinfectant is contained, and measures the temperature of the sample (disinfectant) in a non-contact manner. The radiation temperature sensor is designed to measure the temperature of the disinfectant, but because it measures the temperature based on infrared light emitted from the surface of the optical cell OC, it actually measures the surface temperature of the wall of the optical cell OC. Therefore, if there is a temperature difference between the optical cell OC and the disinfectant, for example, due to differences in the environmental temperatures between the storage location of the concentration measuring device 1 or the optical cell OC and the installation location of the endoscope washer containing the disinfectant, the actual temperature of the disinfectant may not be measured accurately. In contrast, the concentration measuring device 1 and concentration measuring method (mainly the method for calibrating the measured temperature) of this embodiment calibrate the measured value of the radiation temperature sensor 13, as described below, thereby enabling more accurate measurement of the disinfectant temperature. Note that in this embodiment, the reference temperature sensor included in the radiation temperature sensor 13 is used as the environmental temperature sensor, and therefore the radiation temperature sensor 13 functions as both a sample temperature sensor and an environmental temperature sensor. Hereinafter, for convenience, the sample temperature sensor will be referred to as the "sample temperature sensor 131" and the environmental temperature sensor will be referred to as the "environmental temperature sensor 132." The radiation temperature sensor 13 is connected to the control and calculation unit 11, and the reading of the sensor values, etc. is controlled by the control and calculation unit 11.

[0019] The light-emitting unit 141 and the light-receiving unit 142, which are optical sensors for measuring the transmittance of the disinfectant solution, are each positioned so that the optical axis of the light-emitting unit 141 passes through the disinfectant solution in the optical cell OC and so that the light-receiving unit 142 can receive the light that has passed through the disinfectant solution. Here, an example is shown in which the light-emitting unit 141 is positioned facing one side of the optical cell OC and the light-receiving unit 142 is positioned facing the opposite side, but the light-emitting unit 141 and the light-receiving unit 142 may be positioned in any manner as long as they are capable of receiving light that has passed through the disinfectant solution. The light-emitting unit 141 is connected to the control / calculation unit 11 via a driver circuit 1411 that drives the light emission, and the timing of the light emission, etc., are controlled by the control / calculation unit 11. The light-receiving unit 142 is also connected to the control / calculation unit 11, and the control / calculation unit 11 controls the reading of the sensor value and calculates the transmittance based on the sensor value.

[0020] The input unit 15 and output unit 16, which are user interfaces, can be any input interface such as a button, a touch panel, or a voice input unit, or any output interface such as a visual display device such as an indicator or a display screen, or an auditory output unit such as a speaker. Note that the input / output unit is not limited to an interface for the user, and may be any input / output unit for inputting and outputting information to and from other devices.

[0021] The memory unit 12 may be any storage device capable of storing various data, programs, and the like necessary for the operation of the device. The memory unit 12 stores programs for executing the processes described below and data necessary for executing the temperature calibration process described below. One example of this data is "second correlation information between first difference information, which is the difference between the environmental temperature measured by the concentration measuring device 1 and the temperature measured by the calibration sample (a disinfectant solution with a known concentration), and second difference information, which is the difference between the theoretical temperature and the temperature of the calibration sample based on first correlation information between the temperature and transmittance of the calibration sample for the transmittance measured by the concentration measuring device 1." This will be described in detail below.

[0022] The control / calculation unit 11 controls each component of the device and performs various calculations. It is configured using any semiconductor device equipped with a central processing unit (CPU), such as a microcomputer, that performs calculations. The control / calculation unit 11 also functions as a temperature calibration unit that performs the process described below: "acquires differential information between the disinfectant temperature measured by the sample temperature sensor 131 and the environmental temperature measured by the environmental temperature sensor 132, and calibrates the measurement value by the sample temperature sensor 131 using calibration temperature information based on second correlation information for the differential information." The control / calculation unit 11 also functions as a concentration calculation unit that calculates the disinfectant concentration based on the disinfectant temperature information and disinfectant transmittance information after calibration. While not shown in the figure, the control / calculation unit 11 is of course connected to each component via an A / D conversion circuit, various filter circuits, etc., as needed (e.g., by providing appropriate circuits for converting signals into appropriate inputs and outputs to the control / calculation unit 11). Here, the temperature calibration unit, concentration calculation unit, etc. are implemented as software on a general-purpose device (configured by a program running on the control / calculation unit 11) as an example, but some or all of each may also be configured as hardware (for example, by a dedicated IC, etc.).

[0023] Next, the concentration measurement method (mainly the method for calibrating the measurement temperature) of this embodiment will be described with reference to Figure 2 and other figures. Figure 2 is a flowchart showing an outline of the concentration measurement method (mainly the method for calibrating the measurement temperature) of this embodiment. Flows 1 to 5 are the calibration process (setting of parameters for temperature calibration) of the radiation temperature sensor 13 performed for each concentration measurement device 1 in the device manufacturing factory, and Flows 6 to 8 are the process for measuring concentration in the concentration measurement device 1 (calibration of the measurement temperature for this purpose).

[0024] In Flow 1, first correlation information between temperature and transmittance is obtained based on a disinfectant solution (calibration sample) with a known concentration. Specifically, disinfectant solutions of different concentrations, the concentrations of which are measured by HPLC (high performance liquid chromatography), are prepared, and the transmittance of each disinfectant solution is measured under constant temperature conditions, such as 10, 15, 20, 25, 30, and 35°C, by, for example, holding the disinfectant solution in a thermostatic chamber for a certain period of time. FIG. 3 shows an example of a graph of the correlation between the temperature and transmittance of the disinfectant solution (calibration sample) obtained in this manner. Note that the concentration range of the disinfectant solution to be measured may be determined based on the concentration during actual use. In this example, measurements are performed in the range of 0.55 to 0.20%, taking into account that the disinfectant solution (product) in question has a concentration of 0.55% when new and a usable concentration limit of 0.3%.

[0025] Next, an approximate formula (a function of concentration N, temperature T, and transmittance k) for the graph in Fig. 3 is obtained. The concentration N is calculated using the temperature T and transmittance k by the following formula 1: N = iT (Formula 1) ２ k ２ +hTk ２ +gk ２ +fT ２ k+eTk+dk+cT ２ +bT+a where a to i are coefficients. In the following equation 2, which is a transformation of equation 1, A = iT ２ +hT+g, B=fT ２ +eT+d, C=cT ２ + bT + a, it becomes a quadratic function of k (Equation 3). (Equation 2) N = (iT ２ + hT + g) k ２ + (fT ２ +eT+d)k+(cT ２ +bT+a) (Formula 3) N=Ak ２+Bk+C In Equation 3, A, B, and C are each calculated using the least squares method, and coefficients a to i are calculated using the least squares method from the resulting A to C (quadratic functions of T). This results in the coefficients of Equation 1 that approximate the graph in FIG. 3. Note that both the information in the graphed state of FIG. 3 (or information for that purpose) and the information as an approximate formula obtained based on this information correspond to the "first correlation information." The calculation process of the "first correlation information" is performed on an information processing device such as a PC (a device separate from the concentration measurement device 1) that has an application for calculating the above approximate formula, but it may also be configured to be executable on the concentration measurement device 1.

[0026] In Flow 2, the concentration measuring device 1, which is the object of calibration, is used to measure values ​​related to the temperature, transmittance, and environmental temperature of a calibration sample (a disinfectant solution with a known concentration) over time. More specifically, the concentration measuring device 1 (optical cell OC) is temperature-controlled at the environmental (ambient) temperature (e.g., 15°C), and a calibration sample is temperature-controlled at a different temperature (e.g., 30°C). The concentration measuring device 1 is then used to acquire the temperature, transmittance, and environmental temperature of the calibration sample over time. Data is acquired on the progress of thermal equilibrium between the optical cells OC, which are at different temperatures, and the calibration sample placed therein. Note that this time-dependent measurement is preferably performed until a state that can be considered thermal equilibrium (a state in which the temperature difference between the environmental temperature and the liquid temperature has disappeared) is reached. The first difference information T, which is the difference between the measured environmental temperature and the measured temperature of the calibration sample at each point in time, is then acquired. ｓｕｂ１(This calculation process uses an external information processing device such as a PC, as described above, but may also be performed by the concentration measuring device 1.) The above process of Flow 2 is performed under conditions where the environmental temperature (the temperature of the concentration measuring device 1 (optical cell OC)) and the temperature of the calibration sample are different, as described above, and with their high and low temperatures reversed (for example, the opposite of the above example, with the environmental temperature at 30°C and the calibration sample temperature at 15°C). Note that the environmental temperature and the temperature of the calibration sample should preferably be set to near the maximum temperature difference that can be expected in the actual environment in which the concentration measuring device 1 is used. Here, the following conditions are assumed as examples: 1. Environmental temperature 15°C, calibration sample temperature 30°C ( FIG. 4(a) ), 2. Environmental temperature 30°C, calibration sample temperature 15°C ( FIG. 4(b) ). Since slight differences in disinfectant concentration do not have a significant effect on the behavior of thermal equilibrium, the concentration of the calibration sample used to obtain data on the progress of thermal equilibrium may be any (for example, any concentration within the range used in Flow 1), but here, a disinfectant solution of 0.3%, which is the limit concentration for use, is used. Figure 4 shows an example of data obtained in Flow 2. ｏｂｊｅｃｔ is the temperature of the calibration sample acquired by the sample temperature sensor 131, T ＰＴＡＴ is the environmental temperature acquired by the environmental temperature sensor 132, T ｓｕｂ１ is the difference between the two. Figure 4(a) shows the case where the liquid temperature is higher than the ambient temperature, and Figure 4(b) shows the case where the liquid temperature is lower than the ambient temperature. ｓｕｂ１ T ＰＴＡＴ From T ｏｂｊｅｃｔ The example shows a case where T ｏｂｊｅｃｔ From T ＰＴＡＴ (In the processing described below, the sign may be reversed as necessary, and the difference between the sign and the positive sign does not result in any conceptual difference.)

[0027] In flow 3, a process is performed to calculate a theoretical temperature based on the first correlation information for the measured values ​​of the transmittance of the calibration sample measured over time using the concentration measuring device 1 in flow 2. That is, in equation 1, which is the first correlation information, the concentration N (known) and transmittance k (measured over time) of the calibration sample are used to calculate the temperature T (theoretical temperature Tｒｅｆ ) is calculated. ｒｅｆ 5A shows a graph of the liquid temperature when the liquid temperature is higher than the ambient temperature (when the liquid temperature gradually decreases as the liquid reaches thermal equilibrium), and FIG. 5B shows a graph of the liquid temperature when the liquid temperature is lower than the ambient temperature (when the liquid temperature gradually increases as the liquid reaches thermal equilibrium). The processing of flow 3 is also performed on an information processing device such as a PC (a device separate from the concentration measuring device 1), but it may also be configured to be executed on the concentration measuring device 1.

[0028] In flow 4, the theoretical temperature T calculated in flow 3 is ｒｅｆ and the temperature T of the calibration sample acquired by the sample temperature sensor 131 ｏｂｊｅｃｔ The second difference information T ｓｕｂ２ is calculated, and the second difference information T ｓｕｂ２ and the first difference information T obtained in flow 2. ｓｕｂ１ 6 shows the second correlation information between the theoretical temperature T ｒｅｆ and the temperature of the calibration sample T ｏｂｊｅｃｔ and the difference between them, second difference information T ｓｕｂ２ 6A shows the case where the liquid temperature is higher than the ambient temperature, and FIG. 6B shows the case where the liquid temperature is lower than the ambient temperature. FIG. 7 shows the second difference information T ｓｕｂ２ is the Y axis, and the first difference information T ｓｕｂ１ 7A shows a case where the liquid temperature is higher than the ambient temperature (negative second correlation information), and FIG. 7B shows a case where the liquid temperature is lower than the ambient temperature (positive second correlation information). Note that here, the second difference information T ｓｕｂ２ is the Y axis, and the first difference information T ｓｕｂ１ is used as the X axis, but the second difference information T ｓｕｂ２ is the X axis, and the first difference information T ｓｕｂ１ may be used as the Y axis (there is no conceptual difference between the two).

[0029] In flow 5, the graph in FIG. 7 (second difference information T ｓｕｂ２ and the first difference information T ｓｕｂ１In this embodiment, an exponential approximation (coefficient a １ , b １ , c １ (Calculation of T) (Equation 4) ｓｕｂ２ = a １ ・e(b1・Tsub1)+c １ The obtained approximation formula is shown in graph form in Fig. 8. Fig. 8(a) shows the case where the liquid temperature is higher than the ambient temperature (negative second correlation information), and Fig. 8(b) shows the case where the liquid temperature is lower than the ambient temperature (positive second correlation information). That is, the coefficient a corresponding to the negative second correlation information １ , b １ , c １ and a coefficient a corresponding to the positive second correlation information １ , b １ , c １ are acquired. Note that both the graphed state information in FIG. 8 (or information for that purpose) and the information as an approximate formula obtained based on this information correspond to "second correlation information." The process of obtaining the second correlation information in flows 4 and 5 is also performed on an information processing device such as a PC (a device separate from the concentration measuring device 1), but may be configured to be executed on the concentration measuring device 1.

[0030] The above processes from flow 1 to flow 5 are performed for each individual concentration measuring device 1 in the manufacturing factory, and the coefficient a constituting the "second correlation information" corresponding to each individual concentration measuring device 1 is calculated for each individual concentration measuring device 1. １ , b １ , c １ (Coefficient a corresponding to negative second correlation information) １ , b １ , c １ and a coefficient a corresponding to the positive second correlation information １ , b １ , c １ ) are set (stored in the storage unit 12), the calibration process of the radiation temperature sensor 13 (setting of parameters for temperature calibration) is performed.

[0031] The concentration measurement of the disinfectant solution using the concentration measuring device 1 is performed by the processes of Flow 6 to Flow 8. Note that the concentration calculation process (Flow 8) itself can be performed using a conventional method as is, and therefore the explanation here will be omitted, and the explanation will focus on the calibration of the measured temperature of the disinfectant solution, which is necessary for concentration calculation.

[0032] Measurement of the concentration of a disinfectant (a sample with an unknown concentration) using the concentration measuring device 1 is performed by setting an optical cell OC in the device and filling it with disinfectant, based on measurements of the disinfectant temperature by the sample temperature sensor 131, the environmental temperature by the environmental temperature sensor 132, and the transmittance of the disinfectant by the light-emitting unit 141 and the light-receiving unit 142. In flow 6, whether the value obtained by subtracting the disinfectant temperature measured by the sample temperature sensor 131 from the environmental temperature measured by the environmental temperature sensor 132 is positive or negative is determined. If the result of this determination is negative, the processes of flows 7-1 and 8-1 are executed, and if the result is positive, the processes of flows 7-2 and 8-2 are executed. Note that, although 0 is treated as a negative value here, 0 may also be treated as a positive value.

[0033] In flow 7-1, the value (T ｓｕｂ１ ) into the approximation formula (4) (negative second correlation information corresponding to FIG. 8(a)) to obtain the temperature difference information (T ｓｕｂ２ The process of calculating the temperature difference information (T ｓｕｂ２ 8(a) ) is used (added), and thus the control and calculation unit 11 performs a process of calibrating the measured value of the disinfectant temperature by the sample temperature sensor 131. In flow 8-1, the control and calculation unit 11 performs a process of calculating the concentration of the disinfectant using the disinfectant temperature information calibrated in flow 7-1 and the measured value of the disinfectant transmittance. Note that when the result of the determination in flow 6 is positive, the processes in flows 7-2 and 8-2 are the same as the processes in flows 7-1 and 8-1 except that "positive second correlation information corresponding to FIG. 8(b)" is used instead of "negative second correlation information corresponding to FIG. 8(a)", and therefore description thereof will be omitted.

[0034] FIG. 9 shows the concentration measurement results (demonstration experiment results) of a disinfectant solution with a concentration of 0.3% using the concentration measuring device 1. To demonstrate the effect of temperature calibration using the concentration measuring device 1, the graph shows the concentration calculated at the temperature before calibration (i.e., using the measurement value of the sample temperature sensor 131 as is) and the concentration calculated at the temperature after calibration. FIG. 9( a) shows the case where the liquid temperature is higher than the ambient temperature (liquid temperature at the start of measurement set to approximately 25°C, ambient temperature set to approximately 15°C), while FIG. 9( b) shows the case where the liquid temperature is lower than the ambient temperature (liquid temperature at the start of measurement set to approximately 20°C, ambient temperature set to approximately 30°C). In the graph, the dotted line indicates the ±0.01 range of the 0.3% concentration, which is within the specification. As shown in the figure, the concentration based on the pre-calibration temperature is outside the ±0.01 range for a disinfectant solution with a concentration of 0.3% for just under 20 seconds after the start of measurement when the liquid temperature is set to approximately 25°C and the ambient temperature is set to approximately 15°C, and for approximately 45 seconds after the start of measurement when the liquid temperature is set to approximately 20°C and the ambient temperature is set to approximately 30°C. In other words, conventionally, it is necessary to wait at least that long before measuring (since it is not clear exactly how long the actual waiting time should be, a waiting time of at least 60 seconds is required to be safe). In contrast, when the temperature calibration of this embodiment is used, concentration measurements within the standard are obtained approximately 5 seconds after the start of measurement when the liquid temperature is set to approximately 25°C and the ambient temperature is set to approximately 15°C, and approximately 5 seconds after the start of measurement when the liquid temperature is set to approximately 20°C and the ambient temperature is set to approximately 30°C, allowing concentration measurements to be performed in a short time. Immediately after the disinfectant is injected into the optical cell, the measured value may not be stable due to the movement of the liquid caused by the injection, the generation of bubbles, etc. (The data discrepancy immediately after the start in FIG. 9(b) is thought to be largely due to this influence.) Therefore, a predetermined waiting time (for example, about 10 to 15 seconds) may be provided until the liquid in the optical cell settles.

[0035] As described above, the concentration measuring device 1 and the measurement temperature calibration method of this embodiment enable accurate measurement (calibration) of the disinfectant temperature even under conditions where there is a temperature difference between the ambient temperature and the disinfectant temperature. Therefore, the wait time required for the ambient temperature and the disinfectant temperature to become equal, which was previously required, can be shortened or eliminated, allowing concentration measurements to be performed in a short time. While accurately measuring the disinfectant temperature can be a problem when obtaining a calibration curve for this calibration, this embodiment solves this problem by utilizing the correlation between the disinfectant temperature and transmittance and obtaining the solution temperature (theoretical temperature) based on the transmittance. This allows for the correlation (i.e., the calibration curve) between the apparent disinfectant temperature (cell wall temperature) obtained by the sensor and the estimated actual disinfectant temperature (theoretical temperature) to be obtained.

[0036] In this embodiment, positive second correlation information and negative second correlation information are separately acquired depending on whether the difference between the measured ambient temperature and the measured sample temperature during calibration sample concentration measurement is positive or negative. This is because different trends were observed in the direction of decreasing liquid temperature and the direction of increasing liquid temperature, and these are treated separately (to improve accuracy). This trend is thought to be influenced by heat, etc., generated by the concentration measurement device, which is an electronic device. In other words, heat generated by the light-emitting unit and other electronic components during operation tends to bias the direction of increasing liquid temperature, resulting in different trends (not symmetrical) in the direction of decreasing liquid temperature and the direction of increasing liquid temperature. Therefore, in a device configured to ignore the influence of heat, etc., from electronic components, calibration may be performed using only one "second correlation information" rather than separating the positive second correlation information and the negative second correlation information. Furthermore, by introducing a correction value that evaluates the "bias due to the influence of heat, etc., of electronic components," calibration may be performed using only one "second correlation information" (the above bias amount is further calibrated using the correction value).

[0037] When there is no temperature difference between the ambient temperature and the disinfectant temperature (i.e., T ｓｕｂ１is close to 0), the calibration process described above is not necessarily required. ｓｕｂ１ If is close to 0 (below a predetermined value), the concentration may be calculated based on the measurement value of the sample temperature sensor 131 without performing the temperature calibration process in step 7.

[0038] Furthermore, if the difference (absolute value) between the measured environmental temperature and the measured sample temperature when measuring the concentration of a sample with an unknown concentration is greater than the maximum value (absolute value) of the difference between the measured environmental temperature and the measured sample temperature when measuring a calibration sample (a sample with a known concentration), error processing may be performed, such as outputting error information to the output unit 16. This is treated as an error as it is outside the range of calibration data. Instead of treating it as an error, processing may be performed to wait until the temperature difference between the environmental temperature and the disinfectant solution temperature becomes equal to or less than the maximum value of the difference between the measured environmental temperature and the measured sample temperature when measuring the calibration sample, due to thermal equilibrium. Figure 10 shows an example of this processing. The processing in Figure 10 replaces part of flow 6 in Figure 2. As a prerequisite for this processing, T ｓｕｂ１ The absolute values ​​of the maximum values ​​(positive and negative) of are set as thresholds 1 and 2 in the concentration measuring device 1 (storage unit 12). For example, in the processing of flow 2, if the environmental temperature is 16°C and the calibration sample temperature is 29°C, threshold 1 is set to 13°C, and if the environmental temperature is 31°C and the calibration sample temperature is 15°C, threshold 2 is set to 16°C. In step 901, the value (T ｓｕｂ１ ) is judged to be positive or negative. If the result of the judgment is negative, the processes of steps 902 and 903 are executed, and if the result is positive, the processes of steps 904 and 905 are executed. Note that although 0 is treated as a negative process, 0 may also be treated as a positive process. Also, as mentioned above, if the result is 0, the temperature calibration process may be skipped. In step 902, T ｓｕｂ１It is determined whether the absolute value of T exceeds the threshold value 1, and if it does, the output unit 16 displays, for example, "Waiting until the liquid temperature reaches a measurement condition (or simply "Measuring")" (step 903). ｓｕｂ１ The loop process of steps 902 and 903 is performed until the absolute value of T becomes equal to or less than the threshold value 1. ｓｕｂ１ 2, where calibration processing is performed. Note that if the result of the determination in step 901 is positive, the processing in steps 904 and 905 is the same as the processing in steps 902 and 903 except that threshold value 2 is used instead of threshold value 1, and therefore a description thereof will be omitted.

[0039] In the embodiments, disinfectants such as a glutaral aqueous solution or a phthalaral aqueous solution are used as examples of the object to be measured for concentration, but the present invention is not limited to this, and the concept of the present invention can be applied to any sample having a correlation between temperature, transmittance or absorbance, and concentration.

[0040] In the embodiment, a radiation temperature sensor, which is a non-contact temperature sensor, is used as an example of the temperature sensor, but the present invention is not limited to this. For example, the concept of the present invention can be applied to a configuration in which the temperature of the optical cell is measured by any temperature sensor, such as a contact temperature sensor. Furthermore, while the example uses a reference temperature sensor provided in the radiation temperature sensor as the environmental temperature sensor that measures the environmental temperature, the present invention is not limited to this, and any temperature sensor capable of measuring the environmental temperature may be provided separately.

[0041] 1. Concentration measuring device 11. Control and calculation unit (temperature calibration unit) 12. Memory unit 13. Radiation temperature sensor (sample temperature sensor, ambient temperature sensor) 141. Light-emitting unit (optical sensor) 142. Light-receiving unit (optical sensor)

Claims

1. A method for calibrating a measured temperature in a concentration measuring device that performs concentration measurement based on measuring the temperature and transmittance or absorbance of a sample having a correlation between temperature, transmittance or absorbance, and concentration, comprising the steps of: acquiring first correlation information between temperature and transmittance or absorbance based on a sample of known concentration; measuring values ​​related to the temperature, transmittance or absorbance, and environmental temperature of the sample of known concentration over time using a concentration measuring device equipped with a sample temperature sensor, an optical sensor, and an environmental temperature sensor; acquiring first difference information between the measured environmental temperature and the measured sample temperature, and second difference information between a theoretical temperature based on the first correlation information for the measured transmittance or absorbance and the measured temperature of the sample of known concentration; and acquiring, in the temperature measurement of a sample of unknown concentration in the concentration measurement, difference information between the measured sample temperature by the sample temperature sensor and the measured environmental temperature by the environmental temperature sensor, and acquiring calibration temperature information based on the second correlation information for the difference information. calibrating a measured value of the temperature of the sample using the calibration temperature information.

2. A method for calibrating the measured temperature of a concentration measuring device as described in claim 1, wherein in acquiring the second correlation information, positive second correlation information and negative second correlation information are acquired depending on whether the difference between the measured environmental temperature and the measured sample temperature when the concentration of the sample whose concentration is known is positive or negative, and the calibration temperature information is acquired based on either the positive second correlation information or the negative second correlation information depending on whether the difference between the measured environmental temperature and the measured sample temperature when the concentration of the sample whose concentration is unknown is positive or negative.

3. A method for calibrating the measured temperature of a concentration measuring device as described in claim 1 or 2, wherein an error is detected when the absolute value of the difference between the measured environmental temperature and the measured sample temperature when measuring the concentration of a sample whose concentration is unknown is greater than the absolute value of the maximum difference between the measured environmental temperature and the measured sample temperature when measuring a sample whose concentration is known.

4. A concentration measurement device that performs concentration measurement based on measuring the temperature and transmittance or absorbance of a sample having a correlation between temperature, transmittance or absorbance, and concentration, comprising: a sample temperature sensor for measuring the temperature of the sample; an optical sensor for measuring the transmittance or absorbance of the sample; an environmental temperature sensor for measuring the environmental temperature; a memory unit that stores first difference information between the environmental temperature measurement value measured by the concentration measurement device and the temperature measurement value of a calibration sample, and second difference information between a theoretical temperature based on the first correlation information between the temperature and transmittance or absorbance of the calibration sample for the measurement value of the transmittance or absorbance of the calibration sample measured by the concentration measurement device and the measured temperature of the calibration sample; and a temperature calibration unit that acquires difference information between the sample temperature measurement value measured by the sample temperature sensor and the environmental temperature measurement value measured by the environmental temperature sensor, and calibrates the measurement value measured by the sample temperature sensor using calibration temperature information based on the second correlation information for the difference information.

5. A concentration measuring device as described in claim 4, wherein the second correlation information includes positive second correlation information and negative second correlation information according to the positive or negative difference between the measured environmental temperature and the measured sample temperature when the concentration of the calibration sample is measured, and the calibration temperature information is obtained based on either the positive second correlation information or the negative second correlation information depending on the positive or negative difference between the measured environmental temperature by the environmental temperature sensor and the measured sample temperature by the sample temperature sensor.

6. A concentration measuring device as described in claim 4 or 5, wherein error processing is performed when the absolute value of the difference between the environmental temperature measured by the environmental temperature sensor and the sample temperature measured by the sample temperature sensor exceeds a predetermined threshold value.

7. A concentration measuring device as described in claim 4 or 5, wherein, when the absolute value of the difference between the environmental temperature measured by the environmental temperature sensor and the sample temperature measured by the sample temperature sensor exceeds a predetermined threshold, a process of waiting until the difference falls below the threshold is performed.

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