JP2023071283A - pH MEASUREMENT DEVICE - Google Patents

Abstract

To provide a pH measurement device which can stably perform pH measurement by one pH measurement device.SOLUTION: A pH measurement device 1 comprises: a pH meter 10; and a cylindrical vertical container 20 into which a rod-shaped electrode 11 is inserted from a top portion, and performs pH measurement while consecutively introducing an aqueous solution of the measurement target whose pressure is boosted by a pump 2 from an inlet nozzle 21 and simultaneously overflowing from an outlet nozzle 22. The outlet nozzle 22 has a position L1 of a lowermost part of the container side opening higher than a center part L2 in a vertical direction of the vertical container 20 and higher than a position L3 of an uppermost part of the container side opening of the inlet nozzle 21. A bottom part of the vertical container 20 is provided with a drain nozzle 23 and a discharge valve 24 connected thereto.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pH measuring device.

In the water quality management of treated water from various production plants and industrial wastewater, process control is performed to adjust the amount of chemicals added based on the pH measurement results of the aqueous solution to be treated. Therefore, it is necessary to measure the pH value correctly using a highly reliable pH measuring device. Also, in order to confirm that the treated aqueous solution has been properly treated, it is necessary to measure the pH value correctly using a highly reliable pH measuring device. However, as the pH measuring device is used for a long period of time, scales and the like adhere to the pH electrode, and contaminants contained in the aqueous solution to be treated cause the sampling pipe for sending the aqueous solution to the pH measuring device. (Hereinafter, it may be referred to as a supply pipe).

Therefore, the pH measuring device and its sampling pipe are periodically cleaned. For example, in Patent Document 1, a pair of pots each equipped with a pH meter are arranged in parallel in an external circulation line for sampling provided in a coprecipitation tank that receives a waste liquid to be measured for pH. An inflow control valve is provided in the external circulation line, an inlet control valve and an outlet control valve are provided in each pot, and a washing liquid line is connected immediately downstream of these control valves, thereby providing a pair of pots with an inflow control valve. Techniques for switching the flow of waste liquid to wash each pot or washing the sampling pipe as a whole are disclosed.

Japanese Patent Application Laid-Open No. 2016-223775

However, in the technique of Patent Document 1, it is necessary to provide a plurality of pH measuring devices equipped with pH meters. In order to do so, it is necessary to similarly perform maintenance, disassembly and cleaning, etc. for these multiple pH measurement devices, which has required a great deal of cost and time. SUMMARY OF THE INVENTION It is an object of the present invention to provide a pH measuring device capable of stably measuring pH with a single pH measuring device.

In order to achieve the above object, the pH measuring device according to the present invention comprises a pH meter and a cylindrical vertical container having a structure in which a rod-shaped electrode is inserted from the top, and an aqueous solution to be measured pressurized by a pump is supplied to the container. A pH measuring device for measuring pH while continuously introducing from an inlet nozzle and simultaneously overflowing from an outlet nozzle, wherein the lowest position of the container side opening of the outlet nozzle is in the vertical direction of the vertical container. It is higher than the central part and higher than the uppermost position of the container side opening of the inlet nozzle, and the bottom of the vertical container is provided with a drain nozzle and a discharge valve connected to the drain nozzle. and

ADVANTAGE OF THE INVENTION According to this invention, pH measurement can be stably performed with one pH measuring apparatus.

1 is a vertical cross-sectional view of a pH measuring device according to an embodiment of the present invention; FIG. FIG. 2 is a plan view schematically showing a nozzle mounting position of the vertical container of the pH measuring device of FIG. 1; It is a flow chart of the pH measuring equipment built in Example (a) and Comparative Example (b) of the present invention. It is a longitudinal cross-sectional view of a pH measuring device used in a comparative example of the present invention.

Hereinafter, a pH measuring device according to an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, a pH measuring device 1 according to an embodiment of the present invention has a structure in which a pH meter 10, which preferably measures by a glass electrode method, and a rod-shaped pH electrode 11 are inserted from the connecting part at the top. In the straight body of the vertical container 20, an inlet nozzle 21 into which an aqueous solution to be subjected to pH measurement, which is pressurized by a pump (not shown), is continuously introduced; An outlet nozzle 22 is provided through which the aqueous solution of is discharged by overflow. Further, a drain nozzle 23 is provided at the bottom of the vertical container 20 and a discharge valve 24 is connected to the drain nozzle 23 .

The bottom of the vertical container 20 preferably has a substantially inverted conical shape so that the drained liquid can be easily discharged from the drain nozzle 23 after washing. The structure of the top of the vertical container 20 into which the rod-shaped pH electrode 11 is inserted is not particularly limited. For example, as shown in FIG. A structure in which a cap-shaped member 26 is screwed to the projecting central nozzle portion and the pH electrode 11 is inserted through a through hole provided in the central portion of the cap-shaped member 26 is preferable. Alternatively, a structure in which a cap-shaped member is screwed directly into the upper end opening of the vertical container 20 and fixed may be used.

In the pH measuring device 1 of the embodiment of the present invention, the lowermost position _L1 of the container-side opening of the outlet nozzle 22 is higher than the vertical central portion _L2 of the straight body portion of the vertical container 20, and It is higher than the uppermost position _L3 of the container-side opening of the inlet nozzle 21 . With such a structure, a sample of an aqueous solution such as wastewater to be measured extracted from a process pipe or the like for measurement by the pH measuring device 1 is pressurized by a pump and continuously supplied to the pH measuring device 1 while maintaining the state. That is, the pH measuring device 1 can be washed without stopping the operation of the pump.

Specifically, when the aqueous solution to be measured contains adhering matter such as algae that easily adheres to the inside of the vertical container 20, such as seawater, or depending on the measurement conditions, the substance contained in the aqueous solution to be measured may be If the pH electrode 11 is likely to precipitate in the form of deposits such as scale, the pH electrode 11 can be pulled out from the vertical container 20 by removing the flange at the upper end of the vertical container 20 or by removing the cap member. The aqueous solution to be measured is continuously introduced into the vertical container 20 from the inlet nozzle 21, and at the same time, the aqueous solution flowing from the inlet nozzle 21 is allowed to overflow from the outlet nozzle 22. Clean with a cleaning tool such as As a result, deposits such as algae and scales adhering to the inner wall of the vertical container 20 can be easily removed.

After the above cleaning, by opening the discharge valve 24 at the tip of the drain nozzle 23 provided at the bottom, the adhering matter such as algae and scale can be almost completely discharged from the drain nozzle 23. In this way, in order to properly discharge deposits and the like from the drain nozzle 23 at the bottom of the vertical container 20 and prevent the deposits from overflowing from the outlet nozzle 22 together with the aqueous solution, the waste liquid after washing is discharged from the drain nozzle 23. design the capacity of the pump, the size and length of the piping, etc. so that the discharge amount per unit time is greater than the supply amount per unit time of the aqueous solution introduced into the vertical container 20 by the pump. preferably.

As described above, since it is not necessary to stop the operation of the pump when cleaning the pH measuring device 1, the cleaning is almost completed only by cleaning the inside of the vertical container 20 once, and the pH measuring device 1 is installed. This eliminates the need for the operator to make at least two trips to the pump console, which is generally located remotely from the location, to shut down and restart the pump. In addition, if the operation of the pump was stopped during cleaning of the pH measuring device 1, when it was restarted next time, the supply piping system in which the pump was provided would remain full of liquid. The aqueous solution begins to flow at once when the pump is restarted, and due to the physical force of this rapid flow, algae, scales, etc. adhering to the supply piping system come off and flow into the vertical container 20 after cleaning. , the inside of the vertical container 20 needs to be cleaned once or twice.

When the aqueous solution to be measured is seawater, algae adhere to the inside of the pipes more significantly than freshwater. There is a tendency for the algae to flake off and flow into the vertical container 20 in large quantities. Therefore, the pH measuring device 1 of the embodiment of the present invention can obtain a more remarkable effect when the aqueous solution to be measured is seawater, compared to when the aqueous solution is freshwater. In addition, by using the pH measuring device 1 of the embodiment of the present invention, it is possible to reduce the number of times of cleaning the inside of the vertical container 20 as described above. , the continuous measurement time for stable pH measurement can be increased.

The pH measuring device 1 of the embodiment of the present invention has a position L ₁ at the bottom of the container side opening of the outlet nozzle 22 of the vertical container 20 and a position L ₃ at the top of the container side opening of the inlet nozzle 21. is separated from each other in the vertical direction, preferably the radius (D/2) of the container-side opening of the inlet nozzle 21 or more, and half the height H of the straight body portion of the vertical container 20 (H/2 ) or more. By setting the vertical positional relationship between the outlet nozzle 22 and the inlet nozzle 21 as described above, the aqueous solution to be measured is less likely to short-pass or remain excessively inside the vertical container 20. In addition to being able to measure the pH more accurately, it is possible to prevent algae and the like from adhering within the vertical container 20 .

Moreover, in the pH measuring device 1 of the embodiment of the present invention, it is preferable that the outlet nozzle 22 is provided as close to the upper end as possible of the straight body portion of the vertical container 20 . By providing the outlet nozzle 22 on the upper end side of the vertical container 20 in this way, the aqueous solution to be measured introduced into the vertical container 20 from the inlet nozzle 21 can flow smoothly inside the vertical container 20, resulting in a higher Accurate pH measurement becomes possible, and adhesion of algae to the inner wall surface above the outlet nozzle 22 can be suppressed.

Furthermore, in the pH measuring device 1 of the embodiment of the present invention, the type of the discharge valve 24 attached to the drain nozzle 23 is preferably a butterfly valve or a ball valve, more preferably a butterfly valve. In these types of valves, the inner diameter of the opening when the moving part such as a disk or ball is fully opened can be made substantially equal to the inner diameter of the drain nozzle 23, so that the deposits remaining in the vertical container 20 after peeling can be removed by the valve. It can be easily discharged without being disturbed by the movable part of the. In particular, the butterfly valve has a smaller area of the liquid-contacting part inside the valve than other types of valves, so it is possible to minimize the possibility of algae or the like adhering to the inside of the valve.

The material of the wetted part of the pH measuring device 1 of the embodiment of the present invention is not particularly limited as long as it is not easily corroded by the aqueous solution to be measured, and may be polyvinyl chloride (PVC), polypropylene (PP), or the like. A resin or a corrosion-resistant metal such as SUS316 can be preferably used. In particular, it is more preferable that the material of the discharge valve 24 is polyvinyl chloride. Polyvinyl chloride has excellent corrosion resistance, and since it does not rust, the frictional resistance on the inner surface is small, so it is possible to easily remove the peeled deposits, thereby preventing the occurrence of limescale and the adhesion of algae. This is because it can be suppressed.

In the pH measuring device 1 of the embodiment of the present invention, when the angle of the mounting position of the inlet nozzle 21 is 0° when viewed from directly above as shown in FIG. ° or more and 225° or less. By defining the nozzle mounting position (nozzle orientation) as described above, the flow of the aqueous solution inside the vertical container 20 can be made almost linear as a whole. As a result, it is possible to prevent algae, scales, and the like from adhering to the inner wall surface of the vertical container 20 . That is, if the flow inside the vertical container 20 is curved as a whole, the flow becomes slow or stagnant locally on the innermost peripheral side, and algae, scales, etc. adhere to the inner wall surface in contact with this portion. It is not preferable because it is likely to occur.

[Example]
The pH measurement equipment shown in FIG. 3(a) was constructed using the pH measurement device 1 having the structure shown in FIG. was introduced into the pH measuring device 1 at a flow rate of 30 to 60 liters per minute to measure the pH. 1 is used for the pH measuring device 1, a pump manufactured by World Chemical Co., Ltd. (model: YD-16GS-S) is used for the pump 2, and the discharge valve A 16 mm butterfly valve was used.

The height H of the straight body portion of the vertical container 20 was 170 mm, the inner diameter of the inlet nozzle 21 was 16 mm, and the inner diameter of the outlet nozzle 22 was 26 mm. The lowermost position _L1 of the container-side opening of the outlet nozzle 22 is higher than the vertical center _L2 of the straight body of the vertical container 20, and the uppermost position of the container-side opening of the inlet nozzle 21. I made it higher than _L3 . Further, the distance between the lowermost position _L1 of the container-side opening of the outlet nozzle 22 and the uppermost position _L3 of the container-side opening of the inlet nozzle 21 is set to 30 mm in the vertical direction. , the radius of the container-side opening of the inlet nozzle 21 was set to 8 mm or more.

The pH measurement by the pH measuring device 1 was performed for three months, during which cleaning was performed once every two days. During this cleaning, the operation of the pump 2 is not stopped, and the pH electrode 11 is removed while maintaining a state in which waste water is continuously introduced into the vertical container 20 from the inlet nozzle 21 and discharged from the outlet nozzle 22 by overflow. After removing from the vertical container 20, deposits such as algae adhering to the inside of the vertical container 20 were cleaned with a brush. As a result, the cleaning time could be reduced to about 2 minutes per time.

[Comparative example]
The pH measurement of factory effluent was carried out in the same manner as in the above example, except that the pH measurement equipment shown in FIG. 3(b) was constructed using the pH measurement device 101 having the structure shown in FIG. Since the pH measuring device 101 of this comparative example is provided with the inlet nozzle 121 at the bottom of the vertical container 120 unlike the above-described embodiment having the inlet nozzle 21 on the side of the vertical container 20, the pH measuring device 101 It became necessary to stop the operation of the pump 2 during cleaning.

Moreover, in order to discharge the liquid remaining in the vertical container 120 after washing, it became necessary to remove the supply pipe connected to the inlet nozzle 121 at the bottom. Furthermore, after cleaning the inside of the vertical container 120 with a brush, when the supply pipe was connected and the pump 2 was restarted, the algae that seemed to have adhered to the inside of the supply pipe from the inlet nozzle 121 at the bottom of the vertical container 120 Such deposits flowed into the vertical container 120 . For this reason, cleaning with a brush was required again, and the time required to remove adherents such as peeled algae was almost completely longer than in the examples. Specifically, in the example, as described above, it took about 2 minutes per cleaning, whereas in the comparative example it took about 4 minutes, and re-cleaning was required each time. It took about 12 minutes at the longest per time. Furthermore, the case where re-re-washing was required occurred about once every three times, and this re-re-washing required about 15 minutes each time.

Reference Signs List 1, 101 pH measuring device 10 pH meter 11 pH electrode 20, 120 Vertical container 21, 121 Inlet nozzle 22, 122 Outlet nozzle 23 Drain nozzle 24 Discharge valve 25, 125 Lid 26, 126 Cap-like member

Claims (5)

It consists of a pH meter and a cylindrical vertical container having a structure in which a rod-shaped electrode is inserted from the top, and an aqueous solution to be measured, which is pressurized by a pump, is continuously introduced from the inlet nozzle and simultaneously overflowed from the outlet nozzle. In the pH measuring device for measuring pH, the lowest position of the container-side opening of the outlet nozzle is higher than the vertical center of the vertical container and the highest position of the container-side opening of the inlet nozzle. A pH measuring device, wherein the bottom of the vertical container is higher than the upper portion, and a drain nozzle and a discharge valve connected to the drain nozzle are provided at the bottom of the vertical container. 2. The method according to claim 1, wherein the distance between the lowermost part of the outlet nozzle and the uppermost part of the inlet nozzle is equal to or larger than the radius of the container-side opening of the inlet nozzle. pH measuring device. 3. The pH measuring device according to claim 1, wherein said outlet nozzle is provided at the upper end of said vertical container. 4. A pH measuring device according to any one of claims 1 to 3, characterized in that said discharge valve is a butterfly valve. A method for cleaning a pH measuring device comprising a pH meter and a cylindrical vertical container into which a rod-like electrode is inserted from the top, wherein an aqueous solution to be measured, which is pressurized by a pump, is continuously introduced from an inlet nozzle and at the same time. The introduced aqueous solution is caused to overflow from the outlet nozzle, the lowermost position of the container-side opening being higher than the vertical center of the vertical container and higher than the uppermost position of the container-side opening of the inlet nozzle. The rod-like electrode is removed while the container is still in this state, the inside of the container is cleaned, and after the cleaning, a valve provided in a drain nozzle at the bottom of the container is opened to drain the washing waste liquid. cleaning method.

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