JP7128414B2 - pH measurement system, pH meter calibration method and program - Google Patents

Description

The present invention relates to a pH measuring system, a pH meter calibration method, and a program.

Conventionally, an industrial pH meter is used in which calibration with a standard solution is completely automated. In such a pH meter with an automatic calibration function, it is necessary to bring the electrode into contact with the standard solution without contamination with the sample solution, and various methods are employed.
For example, Patent Literature 1 proposes a method of calibrating an electrode by spraying a standard solution onto an electrode that is lifted from a sample solution and held in the air.

The method of Patent Literature 1 enables standard solution calibration simply by pulling up the electrode from the sample solution, and the device structure and sequence operation can be made very simple. However, in the case of this method, the standard solution is continuously supplied at about 100 mL per minute until the glass membrane or the like responds to the pH value of each standard solution and stabilizes, resulting in a large amount of standard solution consumption. In particular, under adverse conditions such as low ambient temperature, it takes 3 minutes or longer to stabilize, and 300 mL or more of standard solution is consumed for one calibration. Therefore, the standard solution must be replenished frequently, which increases running costs and complicates maintenance.
Therefore, in Patent Document 2, an interruption period is provided during which the spraying of the standard solution is interrupted.

Japanese Patent Publication No. 56-38903 JP 2006-322736 A

According to the method of Patent Document 2, the response of the electrode progresses even while the spraying of the standard solution is interrupted. , the time required for standard solution calibration becomes longer. If the time required for calibration with the standard solution is long, it is not preferable because the missing measurement time including the time for cleaning the electrodes before and after the calibration becomes long.
The electrode response time varies depending on the environment of the object being measured. Therefore, in the case of using it for a measurement object that tends to obtain relatively good responsiveness, it is conceivable to set the discontinuation time and the blowing time before and after the discontinuation time to be short.

However, since the response time of the electrode varies depending on the period of use of the electrode, the state of maintenance, etc., it is difficult to uniformly shorten the set time even for a measurement object that can easily obtain a relatively good response.
The present invention has been made in view of the above points. An object of the present invention is to provide a measurement system, a pH meter calibration method, and a program.

In order to achieve the above objects, the present invention employs the following configurations.
[1] A pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end face, an elevating device for elevating the pH composite electrode, and a state in which the pH composite electrode is held in the air by the elevating device, a standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end face of the pH composite electrode; A pH measurement system comprising an arithmetic control unit that controls the whole,
The arithmetic and control device causes the lifting device to hold the pH composite electrode in the air, and the standard solution supply device to spray the standard solution onto the pH composite electrode, while the pH composite electrode is discharged at predetermined determination time intervals. to obtain a potential change amount per the determination time and a rate of change obtained by dividing the potential change amount by the determination time;
If the rate of change becomes equal to or less than a predetermined first rate of change before a predetermined reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is continued. storing as a calibrated potential the potential at the time when it becomes equal to or less than a predetermined final rate of change smaller than the first rate of change;
If the rate of change does not become equal to or less than the first rate of change even after the reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is interrupted within a range in which the droplet end is maintained. After the interruption period ends and the spraying of the standard solution is resumed, the potential at the time when the rate of change becomes equal to or less than the final rate of change is stored as the calibrated potential. pH measurement system.

[2] A pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface, an elevating device for elevating the pH composite electrode, and a state in which the pH composite electrode is held in the air by the elevating device, a standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end face of the pH composite electrode; A pH measurement system comprising an arithmetic control unit that controls the whole,
The arithmetic and control device causes the lifting device to hold the pH composite electrode in the air, and the standard solution supply device to spray the standard solution onto the pH composite electrode, while the pH composite electrode is discharged at predetermined determination time intervals. to obtain a potential change amount per the determination time and a rate of change obtained by dividing the potential change amount by the determination time;
a first time at which the rate of change becomes equal to or less than a predetermined first rate of change; and a second time at which the rate of change becomes a predetermined second rate of change smaller than the first rate of change after the first time. remember the time and
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. stored as an electric potential,
If the evaluation time is equal to or longer than the reference evaluation time, an interruption period is provided for interrupting the spraying of the standard liquid within the range in which the droplet end is maintained, and when the interruption period ends, the spraying of the standard liquid is stopped. A pH measurement system characterized by storing, as a calibrated potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after restarting.

[3] The arithmetic control unit controls the rate of change when the rate of change does not become equal to or less than the first rate of change even after a predetermined reference first time elapses after the start of spraying of the standard liquid, or when the rate of change does not exceed the first rate of change. The pH measurement system according to [2], wherein when the rate of change does not fall below the second rate of change even after a predetermined reference second time elapses after one hour, an abnormality handling process is performed.

[4] A pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface, an elevating device for elevating the pH composite electrode, and a state in which the pH composite electrode is held in the air by the elevating device, a standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end face of the pH composite electrode; A pH measurement system comprising an arithmetic control unit that controls the whole,
The arithmetic and control device causes the lifting device to hold the pH composite electrode in the air, and the standard solution supply device to spray the standard solution onto the pH composite electrode, while the pH composite electrode is discharged at predetermined determination time intervals. to obtain a potential change amount per the determination time and a rate of change obtained by dividing the potential change amount by the determination time;
When the rate of change becomes equal to or less than a predetermined first rate of change before a predetermined reference first time elapses after the start of spraying of the standard liquid, the time when the rate of change becomes equal to or less than the first rate of change is the first time. remembered as
After the first time is stored, if the change rate becomes equal to or less than a predetermined second change rate before the elapse of a predetermined reference second time after the first time, the change rate becomes equal to or less than the second change rate. The time is stored as the second time,
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. stored as an electric potential,
When the rate of change does not become equal to or less than the first rate of change even after the standard first time has passed after the start of spraying of the standard liquid, or when the rate of change has passed the standard second time after the first time If the rate of change does not become equal to or less than the second rate of change, or if the evaluation time is equal to or longer than the reference evaluation time, an interruption period is set to interrupt the spraying of the standard liquid within a range in which the droplet end is maintained. and storing, as a calibrated potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after the suspension period ends and spraying of the standard solution is resumed.

[5] When the arithmetic and control unit does not reduce the rate of change to the final rate of change or less even after a predetermined abnormality determination time elapses after starting to determine whether the rate of change has become the rate of change to the final rate of change or less. , The pH measurement system according to any one of [1] to [4], which performs anomaly handling processing.

[6] A pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface is held in the air, and the pH composite electrode is held so that a droplet end of the standard solution is formed on the lower end surface of the pH composite electrode. A method for calibrating a pH meter in which the potential from the pH composite electrode is stored as a calibration potential while spraying a standard solution onto the electrode,
The rate of change obtained by dividing the amount of change in potential from the pH composite electrode per predetermined determination time by the determination time is a predetermined first change before a predetermined reference first time elapses after the start of spraying the standard solution. when the rate is below the rate, continue spraying the standard solution, and then store the potential at the time when the rate of change is below a predetermined final rate of change smaller than the first rate of change as a calibration potential;
If the rate of change does not become equal to or less than the first rate of change even after the reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is interrupted within a range in which the droplet end is maintained. and storing as a calibration potential the potential at the time when the rate of change becomes equal to or less than the final rate of change after the suspension period ends and spraying of the standard solution is resumed. How to calibrate the meter.

[7] A pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface is held in the air, and the pH composite electrode is held so that a droplet end of the standard solution is formed on the lower end surface of the pH composite electrode. A method for calibrating a pH meter in which the potential from the pH composite electrode is stored as a calibration potential while spraying a standard solution onto the electrode,
A first time at which the rate of change obtained by dividing the amount of change in potential from the pH composite electrode per predetermined determination time by the determination time becomes equal to or less than a predetermined first rate of change, and after the first time, the storing a second time at which the rate of change becomes a predetermined second rate of change smaller than the first rate of change;
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. stored as an electric potential,
If the evaluation time is equal to or longer than the reference evaluation time, an interruption period is provided for interrupting the spraying of the standard liquid within the range in which the droplet edge is maintained, and the spraying of the standard liquid is stopped after the interruption period ends. A method for calibrating a pH meter, comprising storing as a calibrated potential the potential at the time when the rate of change becomes equal to or less than the final rate of change after restarting.

[8] A pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface is held in the air, and the pH composite electrode is held so that a droplet end of the standard solution is formed on the lower end surface of the pH composite electrode. A method for calibrating a pH meter in which the potential from the pH composite electrode is stored as a calibration potential while spraying a standard solution onto the electrode,
The rate of change obtained by dividing the amount of change in potential from the pH composite electrode per predetermined determination time by the determination time is a predetermined first change before a predetermined reference first time elapses after the start of spraying the standard solution. when the rate becomes equal to or less than the rate, storing the time when the change rate becomes equal to or less than the first rate of change as a first time;
When the rate of change becomes equal to or less than a predetermined second rate of change before the elapse of a predetermined reference second time after the first time, the time when the rate of change becomes equal to or less than the second rate of change is stored as a second time. death,
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. stored as an electric potential,
When the rate of change does not become equal to or less than the first rate of change even after the standard first time has passed after the start of spraying of the standard liquid, or when the rate of change has passed the standard second time after the first time If the rate of change does not become equal to or less than the second rate of change, or if the evaluation time is equal to or longer than the reference evaluation time, an interruption period is set to interrupt the spraying of the standard liquid within a range in which the droplet end is maintained. and storing, as a calibration potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after the interruption period ends and spraying of the standard solution is resumed. .

[9] A pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface, an elevating device for elevating the pH composite electrode, and a state in which the pH composite electrode is held in the air by the elevating device, a standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end face of the pH composite electrode; A program for calibrating a pH measurement system comprising an arithmetic control unit that controls the whole,
While causing the lifting device to hold the pH composite electrode in the air, and causing the standard solution supply device to spray the standard solution onto the pH composite electrode, the operation control device controls the flow rate from the pH composite electrode at each predetermined determination time. Acquiring a potential to obtain a potential change amount per the discrimination time and a rate of change obtained by dividing the potential change amount by the discrimination time;
If the rate of change becomes equal to or less than a predetermined first rate of change before a predetermined reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is continued, and then the rate of change is reduced. storing the potential at the time when it becomes equal to or less than a predetermined final rate of change smaller than the first rate of change as a calibrated potential;
If the rate of change does not become equal to or less than the first rate of change even after the reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is interrupted within a range in which the droplet end is maintained. After the interruption period ends and the spraying of the standard solution is resumed, the potential at the time when the rate of change becomes equal to or less than the final rate of change is stored as the calibrated potential. A program to

[10] A pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface, an elevating device for elevating the pH composite electrode, and a state in which the pH composite electrode is held in the air by the elevating device, a standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end face of the pH composite electrode; A program for calibrating a pH measurement system comprising an arithmetic control unit that controls the whole,
While causing the lifting device to hold the pH composite electrode in the air, and causing the standard solution supply device to spray the standard solution onto the pH composite electrode, the operation control device controls the flow rate from the pH composite electrode at each predetermined determination time. Acquiring a potential to obtain a potential change amount per the discrimination time and a rate of change obtained by dividing the potential change amount by the discrimination time;
a first time at which the rate of change becomes equal to or less than a predetermined first rate of change; store the time and
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. Let it be stored as an electric potential,
If the evaluation time is equal to or longer than the reference evaluation time, an interruption period is provided for interrupting the spraying of the standard liquid within the range in which the droplet edge is maintained, and the spraying of the standard liquid is stopped after the interruption period ends. A program for storing, as a calibrated potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after restarting.

[11] A pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end face, an elevating device for elevating the pH composite electrode, and a state in which the pH composite electrode is held in the air by the elevating device, a standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end face of the pH composite electrode; A program for calibrating a pH measurement system comprising an arithmetic control unit that controls the whole,
While causing the lifting device to hold the pH composite electrode in the air, and causing the standard solution supply device to spray the standard solution onto the pH composite electrode, the operation control device controls the flow rate from the pH composite electrode at each predetermined determination time. Acquiring a potential to obtain a potential change amount per the discrimination time and a rate of change obtained by dividing the potential change amount by the discrimination time;
When the rate of change becomes equal to or less than a predetermined first rate of change before a predetermined reference first time elapses after the start of spraying of the standard liquid, the time when the rate of change becomes equal to or less than the first rate of change is the first time. stored in the arithmetic and control unit as
When the rate of change becomes equal to or less than a predetermined second rate of change before a predetermined reference second time elapses after the first time, the time at which the rate of change becomes equal to or less than the second rate of change is defined as the second time. stored in the arithmetic and control unit,
cause the arithmetic and control unit to calculate the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. cause it to be stored in the arithmetic and control unit as an electric potential,
When the rate of change does not become equal to or less than the first rate of change even after the standard first time has passed after the start of spraying of the standard liquid, or when the rate of change has passed the standard second time after the first time If the rate of change does not become equal to or less than the second rate of change, or if the evaluation time is equal to or longer than the reference evaluation time, an interruption period is set to interrupt the spraying of the standard liquid within a range in which the droplet end is maintained. and storing, as a calibrated potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after the interruption period ends and spraying of the standard solution is resumed. Program characterized.

According to the pH measurement system, pH meter calibration method, and program of the present invention, it is possible to shorten the calibration time as much as possible while suppressing the amount of standard solution used when calibrating the electrode by pulling it out of the sample solution. .

1 is an overall configuration diagram of a measurement system according to an embodiment of the present invention; FIG. 1 is a configuration diagram showing an example of a pH composite electrode, an elevating device, and a standard solution supplying device of a measurement system according to an embodiment of the present invention; FIG. 3 is an enlarged perspective view of the periphery of the pH composite electrode of FIG. 2. FIG. FIG. 4 is a partially cutaway cross-sectional view showing a state of standard liquid spraying; FIG. 4 is an explanatory diagram of a droplet edge formed by spraying a standard liquid; It is a flowchart which shows the 1st example of the calibration method which the pH measuring system of embodiment of this invention performs. It is a flowchart which shows the second example of the calibration method which the pH measuring system of embodiment of this invention performs. It is a flowchart which shows the 3rd example of the calibration method which the pH measuring system of embodiment of this invention performs.

The pH measurement system of this embodiment is normally in measurement mode, and can be switched to calibration mode according to a predetermined schedule or according to user's operation. Also, the cleaning mode may be switched to according to a predetermined schedule or according to an operation by the user.
In the measurement mode, the potential obtained from the pH composite electrode is continuously obtained according to the pH of the sample liquid to be measured.
In addition, in the calibration mode, in order to correct the calibration curve information indicating the relationship between the potential obtained from the pH composite electrode and the pH, the potential obtained from the pH composite electrode according to the pH of the standard solution is stored as the calibration potential. The calibration method of the invention is adapted to be performed.
In the cleaning mode, electrodes are cleaned, but standard solution calibration is not performed.

[Device configuration]
As shown in FIG. 1, the pH measurement system of this embodiment includes a pH composite electrode 20, a device main body 1, an elevating device 40, and a standard solution supply device . FIG. 1 shows an example in which an external recorder 7 is connected to the pH measurement system of this embodiment.

The pH composite electrode 20 is normally immersed in the sample liquid and obtains information such as potential according to the pH of the sample liquid. The pH composite electrode 20 is connected to the electrode input terminal 11 of the device main body 1, so that potential and temperature information are continuously obtained and input to the device main body 1 in both the measurement mode and the calibration mode. ing.

The lifting device 40 is connected to the lifting output terminal 12 of the apparatus body 1 . The lifting device 40 lifts and lowers the pH composite electrode 20 in accordance with the lifting signal from the lifting output terminal 12 of the device main body 1 .
The standard solution supply device 70 is connected to the calibration output terminal 13 of the device main body 1 . The standard solution supply device 70 sprays the standard solution onto the sensitive part of the pH composite electrode 20 according to the calibration signal from the calibration output terminal 13 of the device main body 1 .

An external recorder 7 is connected to the data output terminal 14 of the apparatus main body 1 and records the pH and the like of the sample liquid according to the transmission output output from the data output terminal 14 . The data output terminal 14 and the recorder 7 may be directly connected by a cable, or may be connected using a communication system.

The device main body 1 is internally provided with an arithmetic control device 90 that controls the entire system. It also has a display device 5 and an operation unit 6 .
The display device 5 displays the potential obtained by the pH composite electrode 20 and the pH corresponding to the potential. In addition, it is possible to display various kinds of information that the user should be aware of, such as information indicating that the calibration is in progress.

Arithmetic control device 90 includes conversion section 91 , timer section 92 , storage section 93 , calculation section 94 , and calibration instruction section 95 .
A part or all of the arithmetic and control unit 90 excluding the conversion unit 91 may be implemented as an integrated circuit such as an LSI (Large Scale Integration). Also, the timer section 92, the storage section 93, the calculation section 94, and the calibration instruction section 95 may be individually processorized as functional blocks, or may be partially or entirely integrated into a processor.
Also, the method of circuit integration is not limited to LSI, but may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integration circuit technology that replaces LSI appears due to advances in semiconductor technology, an integrated circuit based on this technology may be used.

The conversion section 91 performs impedance conversion and A/D conversion on the potential input from the pH composite electrode 20 and outputs the result to the calculation section 94 .
The timer 92 generates time information and outputs it to the calculator 94 . It should be noted that the time in the present invention simply means a certain moment in the flow of time. However, in order to specify the time, the time from Masako, which is the starting point of the day, may be used as the time. The timer 92 continuously generates time information and inputs it to the calculator 94 in both the measurement mode and the calibration mode.

The storage unit 93 stores various setting values for carrying out the calibration method of the present invention. Various set values include various predetermined values such as a reference first time, a reference evaluation time, and a first rate of change.
Also, the relationship between the calibrated potential obtained by calibration and the pH is stored.

The calculation unit 94 integrates the potential continuously obtained through the conversion unit 91 and the information obtained from the clock unit 92 and the storage unit 93, performs various calculations, and performs the calibration method of the present invention. A command is output to the calibration instruction unit.
The calibration instructing section 95 generates an elevation signal and a calibration signal based on a command from the calculation section 94 and outputs them to the elevation device 40 and the standard solution supply device 70 .
The operation unit 6 is used to cause the pH measurement system to perform operations different from preprogrammed operation procedures and to arbitrarily change various set values.

FIG. 2 is a configuration diagram showing an example of the pH composite electrode 20, the lifting device 40 (only essential parts), and the standard solution supply device 70 (only essential parts) in the pH measurement system of this embodiment.
For example, an air cylinder can be used as the lifting device 40 . In FIG. 2 , the solid line indicates the state when the elevator device 40 descends, and the dashed line indicates the state when the elevator device 40 ascends.

In the example of FIG. 2, the pH composite electrode 20 is inserted into the electrode holder 10 with its lower end exposed. A lead wire 60 of the pH composite electrode 20 is led out from the top of the electrode holder 10 and connected to the electrode input terminal 11 in FIG.
A protective cylinder 30 is fixed to the lower end of the electrode holder 10 to protect the exposed portion of the pH composite electrode 20 . Further, the cleaning calibration tank 50 is arranged at a position surrounding the protective cylinder 30 when the lifting device 40 is lifted.

The electrode holder 10 is gripped by a gripper 41 of an elevating device 40 and is lifted by the elevating device 40 . The pH composite electrode 20 moves up and down together with the electrode holder 10 and the protector 30 as the lifting device 40 moves the electrode holder 10 up and down.
As indicated by the solid line in FIG. 2, the pH composite electrode 20 is immersed in the sample liquid W during the descent, and an output potential corresponding to the pH of the sample liquid W is generated.
On the other hand, when the temperature rises, the pH composite electrode 20 is held in the air so that it can be calibrated or cleaned.

As shown in FIG. 3, in the pH composite electrode 20, the glass membrane 22 of the glass electrode, the liquid junctions 23 of the reference electrode, and the temperature compensating element 24 are exposed on the lower end surface 21a of the electrode body 21, respectively. It is configured as
The protective cylinder 30 has a cutout 31 in a substantially cylindrical member, and a standard solution or the like is allowed to pass through the cutout 31 and is sprayed onto the pH composite electrode 20 .
The cleaning calibration tank 50 is cylindrical and does not have a bottom cover or the like, and the pH composite electrode 20 and the protection cylinder 30 can be moved in and out only by vertical movement by the elevating device 40 .

As shown in FIG. 2, the standard solution supply device 70 of the present embodiment includes a solution sending pipe 71 for sending a standard solution A (for example, a pH 7 standard solution), a standard solution B (a standard solution different from the standard solution A, for example, a pH 4 A liquid feed pipe 72 for feeding a standard solution), a liquid feed pipe 73 for feeding washing water, and a liquid feed pipe 74 for feeding a chemical solution.
A joint 81 of the liquid feeding pipe 71 , a joint 82 of the liquid feeding pipe 72 , a joint 83 of the liquid feeding pipe 73 , and a joint 84 of the liquid feeding pipe 74 for feeding the chemical solution are attached to the cleaning calibration tank 50 .

In FIG. 2, the positions of the joints 81 to 84 are shown vertically for convenience of illustration. The mounting position of is approximately the same height as the exposed portion of the electrode body 21 when the electrode holder 10 is lifted.
The joints 83 and 84 are mounted side by side in the horizontal direction, and their mounting positions are approximately the same height as the lower end side of the protective cylinder 30 when the electrode holder 10 is raised.

As shown in FIG. 4, a nozzle N1 is formed through the joint 81 and the peripheral surface of the cleaning calibration tank 50 substantially horizontally. It is designed to be
Similarly, a nozzle N2 is formed through the joint 82 and the peripheral surface of the cleaning calibration tank 50 substantially horizontally, and the standard solution B is jetted toward the peripheral surface of the electrode main body 21 from this nozzle N2. ing.

Further, a nozzle N3 is formed obliquely penetrating the peripheral surface of the joint 83 and the cleaning calibration tank 50, and cleaning water is jetted from the nozzle N3 toward the lower end surface 21a of the electrode main body 21. .
Similarly, a nozzle N4 is formed obliquely penetrating the peripheral surface of the joint 84 and the cleaning/calibrating tank 50, and the chemical solution is jetted toward the lower end surface 21a of the electrode body 21 from the nozzle N4. .

[Measurement mode]
In the pH measurement system of this embodiment, during the measurement mode, the calculator 94 converts the continuously acquired potential into a temperature-compensated pH measurement value based on the simultaneously acquired temperature information. Then, the obtained pH measurement value and temperature are sequentially displayed on the display device 5 and output from the data output terminal 14 to the recorder 7 . Along with the pH measurement value and the temperature, the recorder 7 may also output the time measured by the timer 92 when the pH measurement value is obtained.

[Calibration mode]
In the pH measurement system of the present embodiment, when the calculation unit 94 recognizes that the calibration cycle set from the previous calibration mode start time has elapsed from the information from the timer unit 92, the operation unit 6 performs calibration. When the start instruction is input, the measurement mode is ended and the calibration mode is started.

The computing unit 94 continuously acquires potential and temperature information from the pH composite electrode 20 even during the calibration mode. However, since the potential of the pH composite electrode corresponding to the pH of the sample liquid W cannot be obtained, the display of the display device 5 and the signal sent from the calculator 94 to the recorder 7 are switched to the display and signal in the calibration mode.
For example, the display device 5 is caused to display a display indicating that it is in the calibration mode. In addition, the recorder 7 outputs a signal indicating that it is in the calibration mode and a signal based on dummy information (pH measurement value, temperature, etc. obtained at the end of the measurement mode).

In the pH measuring system of the present embodiment, the calibration mode includes an ascending process in which the pH composite electrode 20 is raised to the position indicated by the dashed line in FIG. 2 and held in the air, a chemical cleaning process using a chemical solution and cleaning water, Standard solution A step of performing the calibration method of the present invention using standard solution A, water washing step using washing water, standard solution B step of performing the calibration method of the present invention using standard solution B, washing water It consists of a water washing step used and a lowering step in which the pH composite electrode 20 is lowered to the position indicated by the solid line in FIG.

The calibration instruction unit 95, which has been given the information to start the calibration mode, gives an instruction to lift the lifting device 40, and the lifting device 40 follows the instruction to lift the pH composite electrode 20 to the position indicated by the dashed line in FIG. (ascending step).
Next, the calibration instruction unit 95 outputs a chemical cleaning signal to the standard liquid supply device 70, and the standard liquid supply device 70 supplies the cleaning water and the chemical solution in the order of cleaning water, chemical solution, and cleaning water to the pH composite electrode 20. to wash the pH composite electrode 20 (chemical washing step).
Depending on the properties of the sample liquid W, the chemical cleaning process may be changed to a process of cleaning with water only.

After cleaning the pH composite electrode 20 , the calibration instruction unit 95 outputs a calibration signal to the standard solution supply device 70 , and the standard solution supply device 70 first ejects the standard solution A toward the pH composite electrode 20 . , according to the calibration method of the present invention, the potential of the pH composite electrode 20 obtained from the standard solution A is stored as a calibration potential (standard solution A step).
Next, the calibration instruction unit 95 outputs a water cleaning signal to the standard solution supply device 70, and the standard solution supply device 70 jets cleaning water toward the pH composite electrode 20 to clean the pH composite electrode 20 ( water washing process).

After that, the calibration instruction unit 95 outputs a calibration signal to the standard solution supply device 70, and the standard solution supply device 70 ejects the standard solution B toward the pH composite electrode 20, and according to the calibration method of the present invention, standard The potential of the pH composite electrode 20 obtained from liquid B is stored as a calibration potential (standard liquid B step).
Next, the calibration instruction unit 95 outputs a water cleaning signal to the standard solution supply device 70, and the standard solution supply device 70 jets cleaning water toward the pH composite electrode 20 to clean the pH composite electrode 20 ( water washing process).
After that, the lifting device 40 is instructed to descend, and the lifting device 40 follows the instruction to lower the pH composite electrode 20 to the position indicated by the solid line in FIG. exit. After finishing the calibration mode, it returns to the measurement mode.

[Calibration method]
In the calibration method of the present invention performed in the standard solution A step and the standard solution B step, each standard solution is sprayed toward the peripheral surface of the electrode main body 21 while holding the pH composite electrode 20 in the air. The potential obtained from the pH composite electrode 20 is stored as a calibration potential, and stored in the storage unit 93 in association with the pH of the standard solution.
In the calibration method of the present invention, an interruption period for interrupting the spraying of the standard solution is provided as necessary between the start of the spraying of the standard solution and the storage of the calibration potential. The interruption period should be kept within a range in which the tip of the droplet formed by the spraying of the standard solution is maintained.

When the standard solution is sprayed toward the peripheral surface of the electrode main body 21, the standard solution that has fallen along the electrode main body 21 forms a droplet end D on the lower end surface 21a of the electrode main body 21, as shown in FIG. As shown in FIG. 5, the droplet end D covers the glass membrane 22, the liquid junctions 23, 23, and the temperature compensating element 24 of the pH composite electrode 20. As shown in FIG. In other words, the glass membrane 22, the liquid junctions 23, 23, and the temperature compensating element 24 of the pH composite electrode 20 are immersed in the droplet end D. Therefore, the pH composite electrode 20 can generate an output potential corresponding to the pH of the standard solution even though it is held in the air.

This droplet end D eventually falls and disappears. However, even if the continuous blowing is interrupted, the droplet edge D once formed is maintained for a while. That is, even if the spraying of the standard liquid is interrupted after forming the droplet end D, the state in which the glass film 22, the liquid junctions 23, 23, and the temperature compensating element 24 are immersed in the droplet end D can be continued. It is possible to advance the response of the electrode without consuming the standard solution in the meantime.

The time required to form the droplet end D depends on the flow rate of the standard solution to be sprayed, the diameter of the electrode body 21, and the like. Spraying for 60 seconds is sufficient. Moreover, even if the spraying is interrupted, the droplet end D is normally maintained for 60 seconds or longer.

FIG. 6 is a flow chart showing a first example of the calibration method of the present invention carried out in the standard solution A step and the standard solution B step.
While spraying the standard solution (standard solution A or standard solution B) is started, the potential obtained from the pH composite electrode 20 is acquired, and the potential change amount per determination time and the potential change amount are determined at the predetermined determination time. The process of obtaining the rate of change obtained by dividing is started (step A1).

The rate of change in the present invention is obtained based on the continuously acquired potential and the time clocked by the timer 92 . Specifically, it is obtained by dividing the difference _ΔD between the potential _Dx at the time _tx and the potential _Dy at the time _ty after the discrimination time _td from the time _tx by td. For example, when the unit time is 1 second and the discrimination time _td is 3 seconds, the difference (potential change amount) between the acquired potential and the potential acquired 3 seconds before is obtained every 3 seconds. It can be obtained by dividing the potential change amount by 3.

In the present invention, the time at which the rate of change becomes equal to or less than a predetermined value such as the first rate of change is the time at which the arithmetic control unit recognizes that the rate of change has become equal to or less than the predetermined value. The rate of change may be obtained each time the determination time _td elapses, and if the rate of change falls below a predetermined value even once, it may be recognized that the rate of change has fallen below a predetermined value. It is also possible to recognize that the rate of change has become equal to or less than a predetermined value when the number of times has become equal to or less than a predetermined value.
Further, whether or not the rate of change has become equal to or less than a predetermined value such as the first rate of change may be determined by comparing a value obtained by multiplying the predetermined value by the determination time _td and the amount of potential change. .

It is determined whether or not the rate of change obtained each time the determination time _td elapses is equal to or less than a predetermined first rate of change (step A2). If the rate of change is less than or equal to the first rate of change, it is determined whether or not the rate of change obtained each time the determination time _td elapses is less than or equal to a predetermined final rate of change (step A3). Then, when it becomes equal to or less than the final rate of change, the potential at that time is stored as a calibrated potential (step A4).

The final rate of change is a value smaller than the first rate of change. The specific values of the first rate of change and the final rate of change are not particularly limited, but the first rate of change is set to 0.06 to 0.6 mV/sec, and the final rate of change is set to 0.03 to 0.3 mV/sec. More preferably, the first rate of change is set to 0.1-0.3 mV/sec, and the final rate of change is set to 0.03-0.1 mV/sec.

Note that the determination time _td in steps A2 and A3 may be the same or different. It is preferable to set the determination time t _d of step A2 to 1 to 10 seconds and the determination time t _d of step A3 to 1 to 5 seconds _. More preferably, _td is set between 1 and 5 seconds.
Also, step A3 may be repeated multiple times. That is, step A4 may be performed after confirming that the rate of change has reached the final rate of change a plurality of times.

If the rate of change is not equal to or less than the first rate of change in step A2, it is determined whether or not the elapsed time from the start is equal to or greater than a predetermined reference first time (step A5). If it is confirmed in step A5 that the elapsed time from the start is not equal to or longer than the reference first time, the determination in step A2 is repeated.
The reference first time is preferably set to 30 to 120 seconds, more preferably 30 to 90 seconds.

If the elapsed time from the start is equal to or longer than the first reference time in step A5, the spraying of the standard solution is interrupted (step A6) and then restarted (step A7).
The interruption period when the blowing is interrupted in step A6 is preferably set to 15 to 90 seconds, more preferably 30 to 90 seconds.
After the restart, it is determined whether or not the rate of change obtained each time the determination time _td elapses is equal to or less than the final rate of change (step A3). (step A4).

If the rate of change does not reach the final rate of change in step A3 even after the predetermined abnormality determination time has elapsed, an abnormality handling process may be performed.
That is, if the rate of change is not equal to or less than the final rate of change, it is determined whether or not the elapsed time from the start of step A3 is equal to or longer than a predetermined abnormality determination time (step A8). If it is not longer than the predetermined abnormality determination time, step A3 is repeated, and if it is longer than the predetermined abnormality determination time, it proceeds to the abnormality handling process (step A9).
The abnormality determination time is preferably set to 180 to 600 seconds, more preferably 240 to 360 seconds.

It is preferable to perform an abnormality warning process as the abnormality handling process. Examples of the abnormality warning process include displaying a warning message, turning on a warning light, and outputting a warning signal. Further, the re-cleaning may be performed without immediately performing the abnormality warning process, or the re-cleaning may be performed while immediately performing the abnormality warning process.
Re-cleaning includes a step of finishing the spraying of the standard solution and cleaning the pH composite electrode 20 with a chemical solution. Re-washing is a step of washing the pH composite electrode 20 by spraying the washing water and the chemical solution in the order of washing water, chemical solution, and washing water toward the pH composite electrode 20 after finishing the spraying of the standard solution. is preferred.
After the re-cleaning is completed, it is preferable to return to the start of the process of determining the potential change amount and change rate (step A1) while spraying the standard solution onto the pH composite electrode 20 .

If the dirt on the pH composite electrode 20 is not sufficiently removed and the rate of change does not reach the final rate of change even after the predetermined abnormality determination time elapses, the abnormality handling process ( The calibration potential can be stored (step A4) without proceeding to step A9).
Further, when the process proceeds to the abnormality handling process (step A9) again despite having performed re-cleaning once or multiple times, it is preferable to carry out the abnormality warning process without further re-cleaning.

According to the calibration method according to the flowchart of FIG. 6, if the response to the standard solution is fast and the change rate becomes equal to or less than the first change rate before reaching the reference first time, step A4 is performed without providing an interruption period. can proceed to Therefore, the time required for calibration can be shortened.
In addition, if the response to the standard solution is slow and the rate of change does not fall below the first rate of change even after reaching the first reference time, an interruption period is provided to suppress the consumption of the standard solution and ensure a sufficient response. is obtained, the process can proceed to step A4.

FIG. 7 is a flow chart showing a second example of the calibration method of the present invention performed in the standard solution A step and the standard solution B step.
While spraying the standard solution (standard solution A or standard solution B) is started, the potential obtained from the pH composite electrode 20 is acquired, and the potential change amount per determination time and the potential change amount are determined at the predetermined determination time. The process of obtaining the rate of change obtained by dividing is started (step B1).
The rate of change can be obtained in the same manner as in step A1 described above.

It is determined whether or not the change rate obtained each time the determination time _td has passed is equal to or less than a predetermined first change rate (step B2). When the rate of change becomes equal to or less than the first rate of change, the time at that time is stored as the first time (step B3).
After step B3, the calculation of the rate of change is continued, and it is determined whether or not the rate of change obtained each time the determination time _td elapses is equal to or less than a second predetermined rate of change (step B4). When the rate of change becomes equal to or less than the second rate of change, the time at that time is stored as the second time (step B5).
As in step A2 described above, whether or not the rate of change has become equal to or less than a predetermined value such as the first rate of change is determined by comparing the value obtained by multiplying the predetermined value by the determination time _td and the amount of potential change. may be determined by

Next, the difference between the stored first time and second time (second time-first time) is obtained as an evaluation time (step B6).
Then, the obtained evaluation time is compared with a predetermined reference evaluation time (step B7). The reference evaluation time is preferably set to 15 to 60 seconds, more preferably 15 to 30 seconds.
If the evaluation time is less than the reference evaluation time, it is determined whether or not the rate of change obtained each time the discrimination time _td has passed is equal to or less than a predetermined final rate of change (step B8). Then, when it becomes equal to or less than the final rate of change, the potential at that time is stored as a calibrated potential (step B9).

The second rate of change is a value smaller than the first rate of change. The final rate of change is a smaller value than the second rate of change. The specific values of the first rate of change, the second rate of change, and the final rate of change are not particularly limited, but the first rate of change is 6 to 30 mV/sec, the second rate of change is 0.06 to 0.6 mV/sec, It is preferable to set the final rate of change to 0.03 to 0.3 mV / sec, the first rate of change to 10 to 20 mV / sec, the second rate of change to 0.1 to 0.2 mV / sec, the final rate of change to It is more preferable to set 0.03 to 0.1 mV/sec.

Note that the determination times _td in steps B2, B4, and B8 may be the same or different. It is preferable to set the determination time _td of step B2 to 1 to 10 seconds, the determination time _td of step B4 to 1 to 10 seconds, and the determination time td of step _B8 to 1 to 10 seconds. It is more preferable to set _td to 1 to 5 seconds, the determination time _td of step B4 to 1 to 5 seconds, and the determination time _td of step B8 to 1 to 5 seconds.
Further, step B8 may be repeated multiple times. That is, step B9 may be performed after confirming that the rate of change has reached the final rate of change a plurality of times.

If the rate of change is not equal to or less than the first rate of change in step B2, it is determined whether or not the elapsed time from the start is equal to or greater than a predetermined reference first time (step B10). If it is confirmed in step B10 that the elapsed time from the start is not longer than the reference first time, the determination in step B2 is repeated.
The reference first time is preferably set to 30 to 120 seconds, more preferably 30 to 90 seconds.
If the elapsed time from the start is equal to or longer than the first reference time in step B10, the spraying of the standard solution is interrupted (step B12) and then restarted (step B13).

If the rate of change is not equal to or less than the second rate of change in step B4, it is determined whether or not the elapsed time from the first time is equal to or greater than a predetermined reference second time (step B11). When it is confirmed in step B11 that the elapsed time from the start is not equal to or longer than the second reference time, the determination in step B4 is repeated.
The reference second time is preferably set to 15 to 90 seconds, more preferably 30 to 90 seconds.
If the elapsed time from the first time is equal to or longer than the second reference time in step B11, the spraying of the standard liquid is interrupted (step B12) and then restarted (step B13).

If the evaluation time is equal to or longer than the reference evaluation time in step B7, the spraying of the standard solution is interrupted (step B12) and then restarted (step B13).
The interruption period when the blowing is interrupted in step B12 is preferably set to 15 to 90 seconds, more preferably 30 to 90 seconds.
After the restart, it is determined whether or not the rate of change obtained each time the discrimination time _td elapses is equal to or less than the final rate of change (step B8). (step B9).

In step B8, if the rate of change does not reach the final rate of change even after a predetermined time period for judging an anomaly has elapsed, an anomaly handling process may be performed.
That is, if the rate of change is not equal to or less than the final rate of change, it is determined whether or not the elapsed time from the start of step B8 is equal to or longer than a predetermined abnormality determination time (step B14). Then, if it is not longer than the predetermined abnormality determination time, step B8 is repeated.
The abnormality determination time is preferably set to 180 to 600 seconds, more preferably 240 to 360 seconds.

As the abnormality handling process, it is preferable to perform an abnormality warning process in the same manner as in the calibration method (first example) according to the flowchart of FIG. Further, the re-cleaning may be performed without immediately performing the abnormality warning process, or the re-cleaning may be performed while immediately performing the abnormality warning process.
After the re-cleaning is completed, it is preferable to return to the start of the process of determining the potential change amount and change rate (step B1) while spraying the standard solution onto the pH composite electrode 20 .
Moreover, when the process proceeds to the abnormality handling process (step B15) again despite having performed re-cleaning once or multiple times, it is preferable to perform the abnormality warning process without further re-cleaning.

According to the calibration method according to the flow chart of FIG. 7, when the response to the standard solution is fast and the evaluation time is less than the standard evaluation time, the process can proceed to step B9 without providing an interruption period. Therefore, the time required for calibration can be shortened.
In addition, if the response to the standard solution is slow and the time until the rate of change falls below the first rate of change or the time until the rate of change falls below the second rate of change is long, or if the evaluation time is long By providing an interruption period, it is possible to suppress the consumption of the standard solution and proceed to step B9 after a sufficient response is obtained.

FIG. 8 is a flow chart showing a third example of the calibration method of the present invention performed in the standard solution A step and the standard solution B step.
In the example of FIG. 8, when the elapsed time from the start is equal to or longer than the reference first time in step B10, and when the elapsed time from the first time is equal to or longer than the reference second time in step B11, the standard solution Instead of proceeding to step B12 for interrupting the spraying of the air, the process proceeds to abnormality handling processing (step B15). Others are the same as the second example in FIG.

In the example of FIG. 7 or FIG. 8, if the rate of change is not equal to or less than the first rate of change in step B2, step B2 may be repeated without proceeding to step B10.
Further, if the rate of change is not equal to or less than the second rate of change in step B4, step B4 may be repeated without proceeding to step B11.

[Program etc.]
In the above embodiment, an example in which the entire arithmetic and control device is built in the device main body was shown, but part or all of the arithmetic and control device in the measurement system of the present invention may be directly installed in the device main body or using a communication system. It may be an external computer to be connected. In that case, a program is required to cause the external computer to function as part or all of the arithmetic and control device of the present invention and to perform the calibration work corresponding to the implementation of the calibration method of the present invention.

The program may be recorded in advance in the computer, or may be recorded in a computer-readable recording medium and the program recorded in the recording medium may be read into the computer.
Also, a program pre-recorded in a computer and a program recorded in a computer-readable recording medium and read into the computer may be combined.

However, in order for an external computer to function as part or all of the arithmetic and control device in the present invention, it is necessary to input potentials that have undergone impedance conversion and A/D conversion in advance to the computer. Therefore, it is necessary to leave the conversion section in the above-described embodiment in the device main body or to provide the conversion section to the electrode.
Further, the converting section in the above embodiment may not be part of the arithmetic and control unit, and the electrode may have the converting section.

Further, in the above embodiment, an example in which the display device 5 is provided in the device main body 1 is shown, but the display device 5 does not have to be integrated with the device main body, and can be connected directly or using a communication system. It may also be an external display device.

In the calibration method according to the flowchart of FIG. 7, the discrimination time is set to 3 seconds, the first rate of change is set to 12 mV/s, the second rate of change is set to 0.12 mV/s, and the final rate of change is set to 0.06 mV/s. 1 hour was set to 60 seconds, the reference second time was set to 60 seconds, the reference evaluation time was set to 20 seconds, and the interruption time was set to 60 seconds.

When calibration was performed using a pH 7 standard solution using an electrode with a relatively quick response, the first time was 25 seconds after the start, the second time was 40 seconds, and the evaluation time was 15 seconds, which satisfied the standard evaluation time. I didn't.
Therefore, when the spraying of the standard solution was continued without providing an interruption period, the final change rate was reached 70 seconds after the start, and the memorization of the calibrated potential was completed.

After calibrating with pH 7 standard solution using an electrode that has been used for about a year and whose response has become relatively slow, the first time is 30 seconds after the start, the second time is 55 seconds, and the evaluation time was 25 seconds, which was longer than the standard evaluation time.
Therefore, when the spraying of the standard solution was interrupted for 60 seconds and then restarted, the final rate of change was reached 15 seconds after the restart, and the memorization of the calibrated potential was completed. It took 2 minutes and 10 seconds from the start of the first blowing to the completion of memorizing the calibrated potential.

From the above results, it was confirmed that the calibration time can be shortened as much as possible according to the responsiveness of the electrode while suppressing the amount of standard solution used when calibrating the electrode by pulling it out of the sample solution.

DESCRIPTION OF SYMBOLS 1... Device main body, 5... Display device, 6... Operation part, 20... pH composite electrode,
90... Arithmetic control device, 91... Converting unit, 92... Time measuring unit, 93... Storage unit, 94... Computing unit,
95...Calibration instruction unit, 40...Lifting device, 70...Standard solution supply device, 7...Recorder

Claims (11)

a pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface; an elevating device for elevating the pH composite electrode; A standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end surface of the electrode, and the potential obtained by the pH composite electrode is input and the entire system is controlled. A pH measurement system comprising an arithmetic and control unit for
The arithmetic and control device causes the lifting device to hold the pH composite electrode in the air, and the standard solution supply device to spray the standard solution onto the pH composite electrode, while the pH composite electrode is discharged at predetermined determination time intervals. to obtain a potential change amount per the determination time and a rate of change obtained by dividing the potential change amount by the determination time;
If the rate of change becomes equal to or less than a predetermined first rate of change before a predetermined reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is continued. storing as a calibrated potential the potential at the time when it becomes equal to or less than a predetermined final rate of change smaller than the first rate of change;
If the rate of change does not become equal to or less than the first rate of change even after the reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is interrupted within a range in which the droplet end is maintained. After the interruption period ends and the spraying of the standard solution is resumed, the potential at the time when the rate of change becomes equal to or less than the final rate of change is stored as the calibrated potential. pH measurement system. a pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface; an elevating device for elevating the pH composite electrode; A standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end surface of the electrode, and the potential obtained by the pH composite electrode is input and the entire system is controlled. A pH measurement system comprising an arithmetic and control unit for
The arithmetic and control device causes the lifting device to hold the pH composite electrode in the air, and the standard solution supply device to spray the standard solution onto the pH composite electrode, while the pH composite electrode is discharged at predetermined determination time intervals. to obtain a potential change amount per the discrimination time and a rate of change obtained by dividing the potential change amount by the discrimination time;
a first time at which the rate of change becomes equal to or less than a predetermined first rate of change; and a second time at which the rate of change becomes a predetermined second rate of change smaller than the first rate of change after the first time. remember the time and
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. stored as an electric potential,
If the evaluation time is equal to or longer than the reference evaluation time, an interruption period is provided for interrupting the spraying of the standard liquid within the range in which the droplet end is maintained, and the spraying of the standard liquid is stopped after the interruption period ends. A pH measuring system characterized by storing, as a calibrated potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after restarting. The arithmetic and control unit determines whether the rate of change does not become equal to or less than the first rate of change even after a predetermined reference first time elapses after the start of spraying of the standard liquid, or when the rate of change does not exceed the first time 3. The pH measurement system according to claim 2, wherein when the rate of change does not fall below the second change rate even after a predetermined reference second time elapses, an abnormality handling process is performed. a pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface; an elevating device for elevating the pH composite electrode; A standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end surface of the electrode, and the potential obtained by the pH composite electrode is input and the entire system is controlled. A pH measurement system comprising an arithmetic and control unit for
The arithmetic and control device causes the lifting device to hold the pH composite electrode in the air, and the standard solution supply device to spray the standard solution onto the pH composite electrode, while the pH composite electrode is discharged at predetermined determination time intervals. to obtain a potential change amount per the determination time and a rate of change obtained by dividing the potential change amount by the determination time;
When the rate of change becomes equal to or less than a predetermined first rate of change before a predetermined reference first time elapses after the start of spraying of the standard liquid, the time when the rate of change becomes equal to or less than the first rate of change is the first time. remembered as
After the first time is stored, if the change rate becomes equal to or less than a predetermined second change rate before the elapse of a predetermined reference second time after the first time, the change rate becomes equal to or less than the second change rate. The time is stored as the second time,
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. stored as an electric potential,
When the rate of change does not become equal to or less than the first rate of change even after the standard first time has passed after the start of spraying of the standard liquid, or when the rate of change has passed the standard second time after the first time If the rate of change does not become equal to or less than the second rate of change, or if the evaluation time is equal to or longer than the reference evaluation time, an interruption period is set to interrupt the spraying of the standard liquid within a range in which the droplet end is maintained. and storing, as a calibrated potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after the suspension period ends and spraying of the standard solution is resumed. If the rate of change does not become less than or equal to the final rate of change even after a predetermined abnormality determination time elapses after starting to determine whether the rate of change has become less than or equal to the final rate of change, the arithmetic and control unit responds to an abnormality. The pH measurement system according to any one of claims 1 to 4, which performs processing. A pH composite electrode having a glass membrane and a liquid junction disposed on the lower end surface is held in the air, and a standard solution is applied to the pH composite electrode so that a drop tip of the standard solution is formed on the lower end surface of the pH composite electrode. A method for calibrating a pH meter in which the potential from the pH composite electrode is stored as a calibrated potential while spraying a liquid,
The rate of change obtained by dividing the amount of change in potential from the pH composite electrode per predetermined determination time by the determination time is a predetermined first change before a predetermined reference first time elapses after the start of spraying the standard solution. when the rate is below the rate, continue spraying the standard solution, and then store the potential at the time when the rate of change is below a predetermined final rate of change smaller than the first rate of change as a calibration potential;
If the rate of change does not become equal to or less than the first rate of change even after the reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is interrupted within a range in which the droplet end is maintained. and storing as a calibration potential the potential at the time when the rate of change becomes equal to or less than the final rate of change after the suspension period ends and spraying of the standard solution is resumed. How to calibrate the meter. A pH composite electrode having a glass membrane and a liquid junction disposed on the lower end surface is held in the air, and a standard solution is applied to the pH composite electrode so that a drop tip of the standard solution is formed on the lower end surface of the pH composite electrode. A method for calibrating a pH meter in which the potential from the pH composite electrode is stored as a calibrated potential while spraying a liquid,
A first time at which the rate of change obtained by dividing the amount of change in potential from the pH composite electrode per predetermined determination time by the determination time becomes equal to or less than a predetermined first rate of change, and after the first time, the storing a second time at which the rate of change becomes a predetermined second rate of change smaller than the first rate of change;
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. stored as an electric potential,
If the evaluation time is equal to or longer than the reference evaluation time, an interruption period is provided for interrupting the spraying of the standard liquid within the range in which the droplet edge is maintained, and the spraying of the standard liquid is stopped after the interruption period ends. A method for calibrating a pH meter, comprising storing as a calibrated potential the potential at the time when the rate of change becomes equal to or less than the final rate of change after restarting. A pH composite electrode having a glass membrane and a liquid junction disposed on the lower end surface is held in the air, and a standard solution is applied to the pH composite electrode so that a drop tip of the standard solution is formed on the lower end surface of the pH composite electrode. A method for calibrating a pH meter in which the potential from the pH composite electrode is stored as a calibrated potential while spraying a liquid,
The rate of change obtained by dividing the amount of change in potential from the pH composite electrode per predetermined determination time by the determination time is a predetermined first change before a predetermined reference first time elapses after the start of spraying the standard solution. when the rate becomes equal to or less than the rate, storing the time when the change rate becomes equal to or less than the first rate of change as a first time;
When the rate of change becomes equal to or less than a predetermined second rate of change before the elapse of a predetermined reference second time after the first time, the time when the rate of change becomes equal to or less than the second rate of change is stored as a second time. death,
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. stored as an electric potential,
When the rate of change does not become equal to or less than the first rate of change even after the standard first time has passed after the start of spraying of the standard liquid, or when the rate of change has passed the standard second time after the first time If the rate of change does not become equal to or less than the second rate of change, or if the evaluation time is equal to or longer than the reference evaluation time, an interruption period is set to interrupt the spraying of the standard liquid within a range in which the droplet end is maintained. and storing, as a calibration potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after the interruption period ends and spraying of the standard solution is resumed. . a pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface; an elevating device for elevating the pH composite electrode; A standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end surface of the electrode, and the potential obtained by the pH composite electrode is input and the entire system is controlled. A program for performing calibration work on a pH measurement system comprising an arithmetic control unit that performs
While causing the lifting device to hold the pH composite electrode in the air, and causing the standard solution supply device to spray the standard solution onto the pH composite electrode, the operation control device controls the flow rate from the pH composite electrode at each predetermined determination time. Acquiring a potential to obtain a potential change amount per the discrimination time and a rate of change obtained by dividing the potential change amount by the discrimination time;
If the rate of change becomes equal to or less than a predetermined first rate of change before a predetermined reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is continued, and then the rate of change is reduced. storing the potential at the time when it becomes equal to or less than a predetermined final rate of change smaller than the first rate of change as a calibrated potential;
If the rate of change does not become equal to or less than the first rate of change even after the reference first time elapses after the start of spraying of the standard liquid, the spraying of the standard liquid is interrupted within a range in which the droplet end is maintained. After the interruption period ends and the spraying of the standard solution is resumed, the potential at the time when the rate of change becomes equal to or less than the final rate of change is stored as the calibrated potential. A program to a pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface; an elevating device for elevating the pH composite electrode; A standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end surface of the electrode, and the potential obtained by the pH composite electrode is input and the entire system is controlled. A program for performing calibration work on a pH measurement system comprising an arithmetic control unit that performs
While causing the lifting device to hold the pH composite electrode in the air, and causing the standard solution supply device to spray the standard solution onto the pH composite electrode, the operation control device controls the flow rate from the pH composite electrode at each predetermined determination time. Acquiring a potential to obtain a potential change amount per the discrimination time and a rate of change obtained by dividing the potential change amount by the discrimination time;
a first time at which the rate of change becomes equal to or less than a predetermined first rate of change; store the time and
calculating the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. Let it be stored as an electric potential,
If the evaluation time is equal to or longer than the reference evaluation time, an interruption period is provided for interrupting the spraying of the standard liquid within the range in which the droplet edge is maintained, and the spraying of the standard liquid is stopped after the interruption period ends. A program for storing, as a calibrated potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after restarting. a pH composite electrode in which a glass membrane and a liquid junction are arranged on the lower end surface; an elevating device for elevating the pH composite electrode; A standard solution supply device for spraying the standard solution onto the pH composite electrode so that a droplet edge of the standard solution is formed on the lower end surface of the electrode, and the potential obtained by the pH composite electrode is input and the entire system is controlled. A program for performing calibration work on a pH measurement system comprising an arithmetic control unit that performs
While causing the lifting device to hold the pH composite electrode in the air, and causing the standard solution supply device to spray the standard solution onto the pH composite electrode, the operation control device controls the flow rate from the pH composite electrode at each predetermined determination time. Acquiring a potential to obtain a potential change amount per the discrimination time and a rate of change obtained by dividing the potential change amount by the discrimination time;
When the rate of change becomes equal to or less than a predetermined first rate of change before a predetermined reference first time elapses after the start of spraying of the standard liquid, the time when the rate of change becomes equal to or less than the first rate of change is the first time. stored in the arithmetic and control unit as
When the rate of change becomes equal to or less than a predetermined second rate of change before a predetermined reference second time elapses after the first time, the time at which the rate of change becomes equal to or less than the second rate of change is defined as the second time. stored in the arithmetic and control unit,
cause the arithmetic and control unit to calculate the difference between the second time and the first time as an evaluation time;
If the evaluation time is shorter than the predetermined reference evaluation time, continue spraying the standard solution, and then calibrate the potential at the time when the rate of change becomes equal to or less than a predetermined final rate of change smaller than the second rate of change. cause it to be stored in the arithmetic and control unit as an electric potential,
When the rate of change does not become equal to or less than the first rate of change even after the standard first time has passed after the start of spraying of the standard liquid, or when the rate of change has passed the standard second time after the first time If the rate of change does not become equal to or less than the second rate of change, or if the evaluation time is equal to or longer than the reference evaluation time, an interruption period is set to interrupt the spraying of the standard liquid within a range in which the droplet end is maintained. and storing, as a calibrated potential, the potential at the time when the rate of change becomes equal to or less than the final rate of change after the interruption period ends and spraying of the standard solution is resumed. Program characterized.

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