PH detection system and detection method thereof

Abstract

The invention discloses a PH detection system and a detection method thereof, and the system comprises a medium liquid tank and a PH meter, and also comprises a detection storage tank and a cleaning nozzle used for cleaning a PH meter probe; the bottom of the medium liquid tank is communicated with the detection storage tank through a pipeline, and a control valve is arranged on the pipeline; the detection storage tank comprises a detection tank body and a cover plate, the PH meter and the cleaning nozzle are arranged on the cover plate, and a discharge structure is arranged at the bottom of the detection tank body. The liquid level in the storage tank is controlled to be stable by controlling the sampling electric actuator and the discharging electric actuator, so that the measuring part of the PH meter probe is always immersed in the measured medium liquid, and real-time continuous measurement is realized; a measuring medium in the storage tank always flows and is dynamic balance of a liquid level, so that the timeliness of measurement is ensured, and lag is prevented; the PH meter probe is simple and convenient to clean; detection is accurate, and distortion risks are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of pH detection, and particularly to a pH detection system and a detection method thereof. Background Art

[0002] At present, in metallurgical enterprises, especially in the water treatment process, the requirements for water quality are getting higher and higher. For processes such as boilers, sewage treatment, and demineralized water, the measurement of the pH value of water is also increasing, and there are strict requirements for water discharge. The pH value is an important environmental protection index of water. Its measurement is usually to drill an installation hole on the medium liquid pipeline and directly insert a probe to measure. This installation method has great drawbacks. The medium liquid in the pipeline is often not full, and the measured pH value will be untrue at this time. Sometimes the data value will not change, and it cannot timely reflect the change of water quality.

[0003] For the pH meter used for measurement, the probe is divided into an upper signal transmission part and a lower detection part. Its lower detection part is a hollow glass tube probe made of glass, and its measurement part is fragile. The upper signal transmission part is a plastic chuck and a signal wire. If the measured liquid enters this part, it is very easy to cause damage to the pH meter probe. When the pH meter measurement value = 7, it means the water quality is neutral; when pH < 7, it means it is acidic, and the smaller the value, the stronger the acidity; when pH > 7, it means it is alkaline, and the larger the value, the stronger the alkalinity.

[0004] For example, a pH detection device in an organic test process disclosed in Patent CN208818686U includes a base. The number of the bases is three, and the tops of the three bases are all connected with support legs by bolts. The top of the support legs is connected with a stirring tank body by bolts. The top of the stirring tank body is connected with a motor housing by bolts, and a motor mounting frame is welded on the inner wall of the motor housing. By setting a detection tube, a pH detector, a pH detection probe, a sealing cover, a first solenoid valve, a second solenoid valve, and a processor to control the opening of the first solenoid valve, the stirred solution enters the detection tube, the pH detection probe detects the solution, and the information is transmitted to the pH detector through a wire. When the specified value is reached, the alarm light controlled by the processor is turned on, which can remind the staff to avoid contact with air when opening the tank to take materials. At the same time, the pH detection probe can be removed through the sealing cover for cleaning and replacement; the disassembly, cleaning, and detection measurement have the risk of distortion. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a pH detection system and a detection method thereof to achieve the purpose of accurate detection and reducing the risk of distortion.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0007] A pH detection system includes a medium liquid tank and a pH meter, and also includes a detection storage tank and a cleaning spray head for cleaning the probe of the pH meter; the bottom of the medium liquid tank is connected to the detection storage tank through a pipeline, and a control valve is provided on the pipeline; the detection storage tank includes a detection tank body and a cover plate, the pH meter and the cleaning spray head are both arranged on the cover plate, and a discharge structure is provided at the bottom of the detection tank body.

[0008] A stirrer is provided in the medium liquid tank.

[0009] An electromagnetic flowmeter is provided on the pipeline.

[0010] A sampling feed electric actuator is provided on the pipeline.

[0011] A liquid level meter for detecting the liquid level in the detection tank body is provided on the cover plate.

[0012] There are two pH meters, and the two pH meters are respectively arranged on both sides of the cleaning spray head.

[0013] It further includes a recovery trench, and the top of the detection tank body is connected to the recovery trench through an overflow pipe.

[0014] It further includes a PLC controller, and the PLC controller is electrically connected to the electromagnetic flowmeter, sampling feed electric actuator, pH meter, liquid level meter, discharge port electric actuator and clear water addition switch valve in the system.

[0015] The discharge structure is a drain pipe communicated with the recovery trench, and a discharge port electric actuator is provided on the drain pipe.

[0016] A detection method using the pH detection system includes the following steps:

[0017] Step 1: Before entering the pH meter detection point, install the sampling pipeline of the measured medium liquid; on the side wall near the bottom of the tank, tower or tank storing the measured medium liquid, make a sampling port, install an extraction sampling pipe, install a manual switch root valve, install an electromagnetic flowmeter, install an electric actuator to control the sampling flow, and extend the extraction sampling pipeline to a fixed position of the pH meter detection point;

[0018] Step 2: Install one or more stirrers to evenly stir the medium liquid inside, so that the concentration of the medium liquid inside is uniform, so that the measured liquid sampled can truly reflect the actual pH data value;

[0019] Step 3: At the fixed position of the pH meter detection point, make a storage tank. The upper part of the storage tank is an open cylinder, an overflow port is made on the side near the top of the storage tank, and an overflow pipe is installed; the lower part of the storage tank is conical, and the bottom is a discharge port, and an electric actuator is installed at the discharge port to control the discharge flow;

[0020] Step 4: Reserve the inlet position of the sampling pipeline on the cover plate of the storage tank, and install two pH meters, a liquid level gauge and a clear water spray head on the cover plate;

[0021] Step 5: The pH meter, electromagnetic flowmeter, electric actuator, liquid level gauge, clear water addition switch valve and clear water spray head. These devices are respectively provided with control signal cables and power cables and enter the corresponding PLC control system. The control should have a PID automatic regulation function to adjust the liquid level height of the medium in the storage tank through the electric actuator;

[0022] Step 6: The medium liquid discharged from the discharge port and overflow port of the storage tank should flow into the recovery trench, recovery pipe or backflow into the tank body;

[0023] Step 7: Timed by the PLC. When it is time to measure at the set time, first open the discharge port electric actuator to empty the tank body, close it after emptying, and then open the sampling inlet electric actuator. When the liquid level in the storage tank reaches the set level, the sampling inlet electric actuator and the discharge port electric actuator respectively perform PID regulation to stabilize the liquid level in the storage tank and perform stable pH meter measurement;

[0024] Step 8: When the PLC measurement time is up, after the pH meter measurement is completed and the pH value data is obtained, when ending the measurement, the PLC can control the process of cleaning the storage tank body and the pH meter probe, that is, close the sampling inlet electric actuator, open the discharge port electric actuator, and at the same time, open the clear water addition switch valve. The clear water is sprayed onto the inner wall of the tank body and the pH meter probe through the spray head for cleaning. The cleaning time can be adjusted by the PLC;

[0025] Step 9: Controlled by the PLC. When the cleaning time is up and the cleaning is completed, close the discharge port electric actuator. At this time, the clear water addition switch valve continues to add clear water, and the clear water accumulates in the tank body. When the clear water level submerges the pH meter glass probe, close the clear water addition switch valve. At this time, the two pH meter glass probes are immersed in the clear water, realizing the maintenance of the pH meter glass probe when no measurement is being carried out.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The pH detection system and its detection method are reasonably designed. By controlling the sampling electric actuator and the discharge electric actuator, the liquid level in the storage tank is stabilized, so that the measuring part of the pH meter probe is always immersed in the measured medium liquid, realizing real-time and continuous measurement; the measured medium in the storage tank is always flowing, which is a dynamic balance of the liquid level, ensuring the timeliness of measurement and preventing lag; the cleaning of the pH meter probe is simple; the detection is accurate, reducing the risk of distortion. Description of the Drawings

[0028] A brief description will be given below of the content expressed in the accompanying drawings of this specification and the markings in the drawings:

[0029] Figure 1 It is a schematic structural diagram of the detection system of the present invention.

[0030] Figure 2 It is a schematic diagram of the cover plate of the storage tank of the present invention.

[0031] Figure 3 It is a schematic diagram of the control circuit of the present invention. Detailed implementation manners

[0032] The following will further describe in detail the specific implementation manners of the present invention by describing the embodiments with reference to the accompanying drawings.

[0033] As Figures 1 to 3 shown, the pH detection system includes a medium liquid tank, a pH meter, a detection storage tank, and a cleaning spray head for cleaning the probe of the pH meter; the bottom of the medium liquid tank is connected to the detection storage tank through a pipeline, and a control valve is provided on the pipeline; the detection storage tank includes a detection tank body and a cover plate, the pH meter and the cleaning spray head are both arranged on the cover plate, and a discharge structure is provided at the bottom of the detection tank body.

[0034] A stirrer is provided in the medium liquid tank; the medium liquid inside is evenly stirred to make the concentration of the medium liquid inside uniform.

[0035] An electromagnetic flowmeter and a sampling and feeding electric actuator are provided on the pipeline; a liquid level gauge for detecting the liquid level in the detection tank body is provided on the cover plate. The liquid inlet volume can be automatically controlled to ensure that the liquid level in the detection tank is within a suitable range.

[0036] There are two pH meters, and the two pH meters are respectively arranged on both sides of the cleaning spray head. The system also includes a recovery ditch, and the top of the detection tank body is connected to the recovery ditch through an overflow pipe. The discharge structure is a drain pipe connected to the recovery ditch, and a discharge port electric actuator is provided on the drain pipe.

[0037] The system also includes a PLC controller, and the PLC controller is electrically connected to the electromagnetic flowmeter, the sampling and feeding electric actuator, the pH meter, the liquid level gauge, the discharge port electric actuator, and the clear water adding switch valve in the system to achieve automatic control and make the detection operation simple.

[0038] The detection method of the present invention using the pH detection system includes the following steps:

[0039] Before entering the pH meter detection point, install the sampling pipeline for the measured medium liquid; punch a sampling port on the side wall near the bottom of the tank, tower or tank containing the measured medium liquid, install an outlet sampling pipe, install a manual switch root valve, install an electromagnetic flowmeter, install an electric actuator to control the sampling flow, and extend the sampling pipeline to the fixed position of the pH meter detection point;

[0040] Install one or more agitators to evenly stir the medium liquid inside, so that the concentration of the medium liquid inside is uniform, so that the measured liquid sampled can truly reflect the actual pH data value;

[0041] At the fixed position of the pH meter detection point, make a storage tank. The upper part of the storage tank is an open cylinder. An overflow port is punched on the side near the top of the storage tank, and an overflow pipe is installed; the lower part of the storage tank is conical, and the bottom is a discharge port. An electric actuator is installed at the discharge port to control the discharge flow;

[0042] Reserve the feeding port position of the sampling pipeline on the cover of the storage tank, and install two pH meters, a liquid level meter and a clean water spray head on the cover;

[0043] The pH meter, electromagnetic flowmeter, electric actuator, liquid level meter, clean water switch valve and clean water spray head respectively lay control signal cables and power cables and enter the corresponding PLC control system. The control should have a PID automatic adjustment function to adjust the liquid level height of the medium in the storage tank through the electric actuator;

[0044] The medium liquid discharged from the discharge port and overflow port of the storage tank should flow into the recovery ditch, recovery pipe or return tank;

[0045] Timed by the PLC, when it is time to measure at the set time, first open the electric actuator at the discharge port to empty the tank body, close it after emptying, then open the sampling feeding electric actuator. When the liquid level in the storage tank reaches the set level, the sampling feeding electric actuator and the discharge port electric actuator respectively perform PID adjustment to stabilize the liquid level in the storage tank and perform stable pH meter measurement;

[0046] When the PLC measurement time is up, after the pH meter measurement is completed and the pH value data is obtained, when ending the measurement, the PLC can control the process of cleaning the storage tank body and the pH meter probe, that is, close the sampling feeding electric actuator, open the discharge port electric actuator, and at the same time, open the clean water switch valve. The clean water is sprayed onto the inner wall of the tank body and the pH meter probe through the spray head, and the cleaning time can be adjusted by the PLC;

[0047] PLC control. When the cleaning time is up and the cleaning is completed, the electric actuator at the discharge port is closed. At this time, the clear water switch valve is opened to continue adding clear water, and the clear water accumulates in the tank. When the clear water level submerges the glass probe of the pH meter, the clear water switch valve is closed. At this time, the two glass probes of the pH meter are immersed in the clear water, realizing the maintenance of the glass probe of the pH meter when no measurement is being carried out.

[0048] The pH detection system and its detection method of the present invention are reasonably designed. By controlling the sampling electric actuator and the discharge electric actuator, the liquid level in the storage tank is stabilized, so that the measuring part of the pH meter probe is always immersed in the measured medium liquid, realizing real-time and continuous measurement; the measuring medium in the storage tank is always flowing, which is a dynamic balance of the liquid level, ensuring the timeliness of measurement and preventing lag; the cleaning of the pH meter probe is simple; the detection is accurate, reducing the risk of distortion. The liquids coming out of the discharge port and the overflow port are recycled or returned to the tank body without external discharge, preventing secondary pollution.

[0049] The preferred specific example of the present invention is as follows:

[0050] The operation and processing method includes the following:

[0051] Step 1: Before entering the pH meter detection point, install the sampling pipeline of the measured medium liquid. On the side wall near the bottom of the tank, tower or container storing the measured medium liquid, make a sampling port with a diameter of about 10 cm, install a sampling pipe, install a manual switch root valve, install an electromagnetic flowmeter, install an electric actuator to control the sampling flow, and extend the sampling pipeline to a fixed position at the pH meter detection point.

[0052] Step 2: The tanks, towers or containers storing the measured medium liquid are often very large in volume. Especially after standing still for a period of time, the measured medium liquid inside often stratifies. Due to the sedimentation effect of the lower part of the liquid, the concentration will be high, while the upper part of the liquid will be thinner, which leads to a decrease in measurement accuracy. To solve this phenomenon, one or more agitators can be installed on the side (or top) of the tank, tower or container storing the measured medium liquid to evenly stir the medium liquid inside, so that the concentration of the medium liquid inside is uniform. In this way, the measured liquid sampled can more truly reflect the actual pH data value and improve the measurement accuracy.

[0053] Step 3: At the fixed position of the pH meter detection point, make a storage tank. The upper part of the storage tank is an open cylinder. An overflow port is made on the side near the top of the storage tank, and an overflow pipe is installed; the lower part of the storage tank is conical, and the bottom is a discharge port. An electric actuator is installed at the discharge port to control the discharge flow.

[0054] Step 4: Make a flat lid that is larger than the diameter of the cylindrical opening of the storage tank. Reserve the position of the feed inlet from the sampling pipeline on the lid. At the same time, drill two round holes with a diameter of 3 cm (for inserting two glass probes of the pH meter, and the diameter of the round holes can be adjusted according to the size of the pH meter probe), and drill a round hole with a diameter of 5 cm (for inserting the liquid level gauge probe, and the diameter of the round hole can be adjusted according to the size of the liquid level gauge probe).

[0055] Step 5: Two sets of pH meters, 1 electromagnetic flowmeter, two electric actuators, 1 set of liquid level gauges, 1 clear water addition switch valve and a clear water spray head. These devices are respectively provided with control signal cables and power cables and enter the corresponding PLC control system (or are installed in the on-site control instrument box). The control should have a PID automatic regulation function to adjust the liquid level height of the medium in the storage tank through two electric actuators.

[0056] Step 6: The medium liquid discharged from the discharge port and overflow port of the storage tank should flow into the recovery trench, recovery pipe or back into the tank body and cannot be directly discharged externally to prevent environmental pollution.

[0057] Step 7: In the corresponding PLC control system (or in the on-site installed control instrument box), the control logic of 1 clear water addition switch valve can be added, that is, to realize the PLC timed sampling measurement and the process of cleaning the storage tank body and the pH meter probe after the measurement is completed. First, the PLC controls the timing. When the timing time arrives and measurement is to be carried out, first open the discharge port electric actuator to empty the tank body, close it after emptying, and then open the sampling feed electric actuator. When the liquid level in the storage tank reaches the set level, the sampling feed electric actuator and the discharge port electric actuator respectively perform PID regulation to stabilize the liquid level in the storage tank and perform stable pH meter measurement.

[0058] Step 8: When the PLC measurement time arrives and the pH meter measurement is completed and the pH value data is obtained, at the end of the measurement, the process of cleaning the storage tank body and the pH meter probe can be controlled by the PLC, that is, close the sampling feed electric actuator, open the discharge port electric actuator, and at the same time, open the clear water addition switch valve. The clear water is sprayed onto the inner wall of the tank body and the pH meter probe through the spray head, and the cleaning time can be adjusted by the PLC.

[0059] Step 9: Under PLC control, when the cleaning time arrives and the cleaning is completed, close the discharge port electric actuator. At this time, the clear water addition switch valve continues to add clear water, and the clear water accumulates in the tank body. When the clear water level submerges the glass probes of the pH meter, close the clear water addition switch valve. At this time, the two glass probes of the pH meter are kept in the clear water, realizing the maintenance of the glass probes of the pH meter when no measurement is being carried out.

[0060] The implementation process is as follows:

[0061] 1. Get a preliminary understanding of the physical and chemical properties of the medium liquid to be tested and measured, whether it is corrosive, etc., and whether it is suitable for pH meter measurement.

[0062] 2. Install one or more agitators on the side (or top) of the box, tower or tank containing the measured medium liquid to evenly stir the medium liquid inside so that the concentration of the medium liquid inside is uniform.

[0063] 3. On the side wall of the tank body near the bottom of the measured medium liquid, make a sampling port (the diameter cannot be too small to prevent the sampling port from being blocked), and install the corresponding diameter of the lead-out pipeline, root valve, electromagnetic flowmeter, and electric actuator equipment. The lead-out pipeline and related equipment need to select the material and anti-corrosion requirements of the pipeline according to the properties of the measured medium liquid.

[0064] 4. Make a storage tank with materials that meet the anti-corrosion requirements. The upper part of the storage tank is an open cylinder. An overflow port is punched on the side of the top of the storage tank, and an overflow pipe is installed. The lower part of the storage tank is conical, and the bottom is a discharge port. An electric actuator is installed at the discharge port to control the discharge flow. The size of the storage tank does not need to be too large, and the size can be defined by yourself, as long as it has a certain height.

[0065] 5. Make a flat lid that is slightly larger than the cylindrical opening of the storage tank. On the lid, reserve the feed port position from the sampling line. At the same time, punch two 3CM diameter holes on the lid (for inserting two pH meter glass probes, the diameter of the holes can be adjusted according to the size of the pH meter probes), and punch a 5CM diameter hole (for inserting the level meter probe, the diameter of the holes can be adjusted according to the size of the level meter probe). The lid is movable and can be removed and covered, and can be equipped with a handle for easy holding.

[0066] 6. Select the following equipment: two sets of pH meters, one electromagnetic flowmeter, two electric actuators, one set of liquid level meter, one clean water switch valve and clean water nozzle. These equipments have signal remote transmission function. Place control signal cables and power cables respectively, and enter the corresponding PLC control system (or the control instrument box installed on site). The control should have PID automatic adjustment function, which is used to adjust the medium liquid level in the storage tank through two electric actuators. The interface between the incoming cable and each equipment should be waterproof and sealed to prevent rainwater or medium liquid from entering the equipment.

[0067] 7. Open the root valve and take out the sampling medium liquid from the tank. The PLC control system (or the on-site control instrument box) automatically adjusts the valve opening of the sampling feed electric actuator according to the actual sampling flow measured by the electromagnetic flowmeter, thereby stably controlling the flow rate of the medium liquid flowing into the storage tank.

[0068] 8. After the medium liquid flows into the storage tank, the liquid level gauge can measure the actual liquid level in the storage tank. The PLC control system (or on-site control instrument box) automatically adjusts the opening of the discharge electric actuator valve according to the actual liquid level, thereby stably controlling the size of the discharge flow at the bottom of the storage tank.

[0069] 9. Both the sampling feed electric actuator and the discharge electric actuator use the PID adjustment function. In the PLC control system (or on-site control instrument box), first set: the set value of the medium liquid flow rate flowing into the storage tank, and adjust the P (proportion), I (integration time), and D (differential time) parameters to achieve the function of automatically adjusting the sampling feed electric actuator according to the flow set value. Then set: the set value of the liquid level in the storage tank, and adjust the P, I, and D parameters to achieve the function of automatically adjusting the discharge electric actuator according to the liquid level set value.

[0070] 10. When the medium flow rate entering the storage tank is greater than the discharge flow rate of the storage tank, the liquid level in the storage tank rises; when the medium flow rate entering the storage tank is less than the discharge flow rate of the storage tank, the liquid level in the storage tank drops.

[0071] 11. By controlling the sampling feed electric actuator valve and the discharge electric actuator valve, the liquid level in the storage tank reaches a certain height, which can submerge the measuring part of the glass probe inserted by the pH meter from the lid, and automatically adjust and maintain this liquid level to achieve dynamic balance of the liquid level, so that the glass probe part of the pH meter is always submerged in the medium liquid, realizing the function of continuous real-time measurement and detection.

[0072] 12. Timed by the PLC, when it is time to measure at the set time, first open the discharge port electric actuator to empty the tank body, then close it after emptying, and then open the sampling feed electric actuator. When the liquid level in the storage tank body reaches the set level, the sampling feed electric actuator and the discharge port electric actuator respectively perform PID adjustment to stabilize the liquid level in the storage tank body and conduct stable pH meter measurement.

[0073] 13. When the measurement is completed, the PLC controls the process of cleaning the storage tank body and the pH meter probe, that is, closes the sampling feed electric actuator, opens the discharge port electric actuator, and at the same time, opens the clear water switch valve. The clear water is sprayed through the nozzle to clean the inner wall of the tank body and the pH meter probe, and the cleaning time can be adjusted by the PLC.

[0074] 14. Controlled by the PLC, after the cleaning is completed, close the discharge port electric actuator. At this time, the clear water switch valve continues to add clear water, and the clear water accumulates in the tank body. When the clear water level submerges the pH meter glass probe, close the clear water switch valve. At this time, the two pH meter glass probes are immersed in the clear water, realizing the maintenance of the pH meter glass probe when no measurement is being carried out.

[0075] The above is only a description of the preferred embodiments of the present invention, and the above technical features can be arbitrarily combined to form multiple embodiment solutions of the present invention.

[0076] The present invention has been described exemplarily above in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A pH detection system, comprising a medium liquid tank and a pH meter, characterized in that: It also includes a detection storage tank and a cleaning spray head for cleaning the pH meter probe; the bottom of the medium liquid tank is connected to the detection storage tank through a pipeline, and a control valve is provided on the pipeline; the detection storage tank includes a detection tank body and a cover plate, the pH meter and the cleaning spray head are both arranged on the cover plate, and a discharge structure is provided at the bottom of the detection tank body.

2. The pH detection system according to claim 1, characterized in that: A stirrer is provided in the medium liquid tank.

3. The pH detection system according to claim 1, characterized in that: An electromagnetic flowmeter is provided on the pipeline.

4. The pH detection system according to claim 1, wherein: A sampling feed electric actuator is provided on the pipeline.

5. The pH detection system according to claim 1, wherein: A liquid level gauge for detecting the liquid level in the detection tank body is provided on the cover plate.

6. The PH detection system according to claim 1, wherein: There are two pH meters, and the two pH meters are respectively arranged on both sides of the cleaning spray head.

7. The pH detection system according to claim 1, wherein: It also includes a recovery ditch, and the top of the detection tank body is connected to the recovery ditch through an overflow pipe.

8. The pH detection system according to claim 1, characterized in that: It also includes a PLC controller, and the PLC controller is electrically connected to the electromagnetic flowmeter, sampling feed electric actuator, pH meter, liquid level gauge, discharge port electric actuator, and clear water switch valve in the system.

9. The pH detection system according to claim 7, wherein: The discharge structure is a drain pipe connected to the recovery ditch, and a discharge port electric actuator is provided on the drain pipe.

10. A detection method using the pH detection system according to any one of claims 1 to 9, characterized in that: It includes the following steps: Step 1: Before entering the pH meter detection point, install the sampling pipeline of the measured medium liquid; on the side wall near the bottom of the installed measured medium liquid tank, tower or tank body, punch a sampling port, install a lead-out sampling pipe, install a manual switch root valve, install an electromagnetic flowmeter, install an electric actuator to control the sampling flow, and extend the lead-out sampling pipeline to a fixed position of the pH meter detection point; Step 2: Install one or more stirrers to evenly stir the medium liquid inside, so that the concentration of the medium liquid inside is uniform, so that the measured liquid sampled can truly reflect the actual pH data value; Step 3: At the fixed position of the pH meter detection point, make a storage tank. The upper part of the storage tank is an open cylinder, an overflow port is punched on the side near the top of the storage tank, and an overflow pipe is installed; the lower part of the storage tank is conical, and the bottom is a discharge port. An electric actuator is installed at the discharge port to control the discharge flow; Step 4: Reserve the feed port position of the sampling pipeline on the cover plate of the storage tank, and install two pH meters, a liquid level gauge and a clear water spray head on the cover plate; Step 5: For the pH meter, electromagnetic flowmeter, electric actuator, liquid level gauge, clear water switch valve and clear water spray head, these devices respectively lay control signal cables and power cables and enter the corresponding PLC control system. The control should have a PID automatic adjustment function to adjust the height of the medium liquid level in the storage tank through the electric actuator; Step 6: The medium liquid discharged from the discharge port and overflow port of the storage tank should flow into the recovery ditch, recovery pipe or reflux tank body; Step 7: Timed by the PLC, when it is time to measure at the set time, first open the discharge port electric actuator to empty the tank body, close it after emptying, then open the sampling feed electric actuator. When the liquid level in the storage tank body reaches the set level, the sampling feed electric actuator and the discharge port electric actuator respectively perform PID adjustment to stabilize the liquid level in the storage tank body and perform stable pH meter measurement; Step 8: When the PLC measurement time arrives, after the measurement of the pH meter is completed and the pH value data is obtained, when ending the measurement, the PLC can control the process of cleaning the storage tank body and the pH meter probe, that is, closing the sampling and feeding electric actuator, opening the discharge port electric actuator, and at the same time, opening the clear water switch valve. The clear water is sprayed through the nozzle to clean the inner wall of the tank body and the pH meter probe, and the cleaning time can be adjusted by the PLC; Step 9: Under the control of the PLC, when the cleaning time arrives and the cleaning is completed, close the discharge port electric actuator. At this time, the clear water switch valve continues to add clear water, and the clear water accumulates in the tank body. When the clear water level submerges the pH meter glass probe, close the clear water switch valve. At this time, the two pH meter glass probes are immersed in the clear water, realizing the maintenance of the pH meter glass probe when no measurement is being carried out.

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