JP3878859B2 - Flow stabilization unit and analyzer in front of it - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to the structure of a pretreatment unit for stabilizing the flow rate in order to remove and mitigate the influence of fluctuations in flow velocity when introducing sample water into a water quality analyzer or the like for measuring sample water, It relates to a water quality analyzer using this pretreatment unit.
[0002]
[Prior art]
In various fields of the industry, it is common to introduce a sample fluid into a water quality analyzer and continuously measure it. For example, in the management of clean water, water quality such as residual chlorine concentration, turbidity, chromaticity, pH, conductivity, dissolved oxygen amount and the like is measured for the purpose of being suitable for beverages. In addition, the quality of river water is also measured to maintain the environment. Various water quality measurements are carried out in each industrial field. For example, industrial boilers are used in many industries, including thermal and nuclear power plants. In order to operate the boiler stably, it is required to maintain the quality of boiler water used in the boiler within a predetermined range. Therefore, in order to monitor the quality of boiler water, sample water is sampled directly from the pipe of boiler water (including condensate and feed water) and automatically measured by an analyzer or used for manual analysis.
[0003]
In this case, there are two methods for feeding the sample water to the water quality analyzer: the sample water source itself having a pressure and being sent at this pressure; In continuous sampling, the pressure of the water source fluctuates in the former case, and in many cases, the flow rate of the sample water changes due to changes over time of the pump in the latter case. On the other hand, many detectors of water quality analyzers enable stable detection when the flow rate of sample water is constant. For example, a detector for residual chlorine can obtain a diffusion current as a stable signal when the flow rate is constant.
[0004]
Therefore, many analyzers are usually provided with a pretreatment unit as shown in FIG. 1 in order to stabilize the flow rate of the sample water reaching the detector. This is usually called the head tank system, where a fixed volume tank is placed at a certain height of the analyzer and sample water is usually introduced from the bottom into the head tank. Drain and drain. The flow rate of the sample water to the detector is always constant by the differential pressure determined by the difference in height between the position of the head tank and the position of the detector, and a stable flow rate can be maintained. Also, instead of installing a large-capacity head tank, a piping system that attempts to absorb the fluctuations in flow rate by reducing the proportion of space by placing a 2-3m pipe on the overflow branch as shown in Fig. 2 There is also a proposed method.
[0005]
[Problems to be solved by the invention]
The conventional head tank system for stabilizing the flow rate of the sample water to the detector is (1) the size of the head tank is usually about 50 to 100 mm in inner diameter, and this part becomes larger, and (2) therefore the sample It takes time to replace the water. (3) When the sample water supply stops, the sample water stored in the tank may flow backward. Therefore, it is necessary to attach a check valve to the pipe that supplies the tank water. (4) There was a problem that it took time to start measurement at the first startup. In addition, when 10 to 20 analyzers provided with such head tanks are arranged and a large number of measurement objects at multiple measurement points are collectively analyzed for water quality, a large space is occupied, which is inconvenient. In addition, it was inconvenient to properly manage the flow rate from the inlet to the outlet of the sample water by arranging this flow stabilization unit at the optimal position of the analyzer.
[0006]
In addition, in the piping system that does not occupy a large space as shown in FIG. 2, if the piping is not lengthened, the absorption width of the flow velocity fluctuation is small, so there is a risk that water will be ejected from the air opening when the flow velocity changes suddenly. In order to avoid this problem, the water distribution pipes had to be thickened to some extent.
[0007]
[Means for Solving the Problems]
The inventors have studied the above problems, and the sample water inlet for introducing the sample water and a double pipe communicating with the sample water have a bottom between the outer pipe and the inner pipe. A flow passage having the void portion as a flow passage, a sample water outlet provided in the outer tube, an overflow outlet forming an upper end portion of the inner tube further above the outlet, and an inner wall void portion of the inner tube as a discharge passage. The flow stabilization unit according to claim 1, which is constituted by a draining part that performs the above and an outer pipe that is higher than the overflow part. In this flow stabilization unit, when the flow rate from the sample water inlet to the sample water inlet increases, the structure differs from the overflow part of the conventional piping system. Once it flows in, it is further drawn into the drainage side by the flow, and an effective drainage effect can be obtained by the aspirator effect.
[0008]
As a result, even if the inner diameter is about 6 mm, the flow rate is 100 to 200 ml / min. If the height of the outer tube at a position higher than the overflow portion is about 50 cm from the overflow portion. If the sample water is introduced into a general water quality analyzer with a change in flow rate, there will be no inconvenience of jetting from the tip of the outer tube. In this way, a flow stabilizing unit having a flow gap of 1 mm is formed by using a tube having an outer diameter of 9 mm and an inner diameter of 6 mm for the inner tube and a tube having an inner diameter of 11 mm and an outer diameter of 14 mm for the outer tube. As a whole, it is possible to construct a compact flow stabilization unit with an outer diameter of about 15 mm.
[0009]
According to a second aspect of the present invention, the flow rate stabilizing unit according to the first aspect of the present invention is arranged between the sample water inlet of the water quality analyzer and the detector. By arranging in this way, the arrangement space of the conventional water quality analyzer can be greatly reduced.
Furthermore, the invention of claim 3 is arranged such that the position of the sample water outlet of the flow rate stabilization unit of claim 1 is higher than the position of the drainage port of the detector of the water quality analyzer, and the analyzer from the sample water outlet. This is a water quality analyzer characterized in that the pipe leading to is detoured to a position lower than the detector. Even if the sample water is interrupted or is not supplied due to such an arrangement, the sample water in the detector is U-shaped without providing a check valve in front of the flow stabilization unit. Since the lower tip of the detector is dried and the sample water is introduced again, the problem that the measurement is hindered is also eliminated.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described below.
Sample water for water quality analyzers that continuously output analysis data can be used for boilers that have relatively gentle water pressure, such as general environmental water, such as general river water, which does not discharge pressure, or water. There are a wide variety of things that have high pressure such as water. Since boiler water is high-temperature and high-pressure, the sample water is introduced into a water quality analyzer or a water intake for manual analysis after the pressure is reduced to a constant pressure and temperature. Taking boiler water as an example, the sample water that has passed through the pressure reducing device leads to an analyzer for automatic analysis placed from the sample water port. The analyzer includes a pH meter, dissolved oxygen meter, conductivity meter, hydrazine meter, silica meter, etc., each of which is adjusted to a predetermined flow rate with a needle valve, and the flow rate is confirmed with a flow meter. In addition, sample water is introduced. The sample water that has passed through the analyzer is usually led to a drain pipe whose upper end is open to the atmosphere, and returned to a drain outlet to be drained. In this case, the flow rate of the sample water to the detector of the water quality analyzer changes when the operating condition of the boiler changes. In addition, when the boiler is stopped, the pressure drops rapidly, so that the sample water may flow backward due to the influence.
[0011]
【Example】
FIG. 1 shows an example of a water quality analyzer 9 provided with a conventional flow rate stabilization unit 8. After reaching the head tank 15 after the flow rate is adjusted by the needle valve 14 through the sample water inlet 10. The head tank 15 usually has a cylindrical shape with an inner diameter of 40 to 70 mm, and is placed in an overflow tank 16 having a larger diameter. The sample water overflowing the head tank 15 is discharged through the drainage section 7 via the overflow tank 16. The lower part of the head tank 15 reaches the detector 11 through the sample water outlet 5. In many cases, a valve 17 for adjusting the flow rate and a flow meter 12 for confirming the flow rate are attached in front of the detector 11. The outlet of the detector 11 is discharged after passing through the detector outlet 11b which is one step higher than the position where the detector tip 11a is present. This is to ensure that the tip of the detector is immersed in the sample water. The head tank 15 is usually manufactured by processing a vinyl chloride pipe or the like, and this tank is usually fixed after determining a position and height to be installed in advance.
[0012]
FIG. 2 shows a flow rate stabilization unit 8 of a piping system that does not use a tank. In this method, if the pipe is not extended 2-3 m in the upper part, the absorption width of the flow velocity fluctuation is small, so there is a possibility that water may be ejected from the air opening when the flow velocity suddenly changes. Therefore, the water distribution pipes had to be thickened to some extent.
[0013]
FIG. 3 shows a flow stabilization unit according to the present invention. For example, a water quality analyzer for boiler water for business use will be described. The high-pressure sample water of the boiler is normally kept at a constant temperature and pressure through the decompression mechanism 18 in advance, and then the water quality analyzer through the sample water inlet 10. 9 will be introduced. Since the boiler changes the amount of steam according to the power generation amount, the pressure of the sample water also changes, and the flow rate of the sample water changes according to the change in pressure. If the flow rate fluctuation of the sample solution is transmitted to the detector 11 as it is, an indication error occurs in many detectors such as a dissolved oxygen meter and a pH meter. Therefore, conventionally, a flow rate stabilizing unit 8 as shown in FIGS. 1 and 2 is provided in front so as not to be affected by the fluctuation of the flow velocity.
[0014]
In the present invention, a sample water inlet 1 for introducing sample water, and a double pipe communicating with the sample water, the lower part of the gap between the outer pipe 2 and the inner pipe 3 has a bottom. The flow passage 4 having the flow passage as a flow passage, the sample water outlet 5 provided in the outer pipe, the overflow outlet 6 at a position higher than the outlet and forming the upper end of the inner pipe, and the inner wall void of the inner pipe The flow rate stabilizing unit 8 according to claim 1 is constituted by the drainage part 7 as a path and the outer pipe 2 higher than the overflow outlet 6. Since the structure is different from the overflow part of the conventional piping method, it flows from the entire periphery into the gap of the inner pipe from the overflow part, and once it flows, it draws further into the drainage side by that flow and has an effective drainage effect due to the aspirator effect Since it can be obtained, the head pressure can be kept constant.
[0015]
The invention of claim 2 is such that the flow rate stabilization unit 8 is arranged between the sample water inlet 10 of the water quality analyzer 9 and the detector 11. In the invention of claim 3, the pipe coming out of the sample water outlet 5 reaches the detector 11, but is arranged around a position lower than the detector tip 11 a. The outlet from the detector 11 is discharged after passing through the detector outlet 11b at a position one step higher than the position where the detector tip 11a is present. In the middle of the path, a valve 17 may be appropriately attached to the flow meter 12 in order to confirm the flow rate to the detector.
[0016]
With this arrangement, even when the boiler stops and the sample water is not supplied or the sample water in the pipe on the sample water supply side has drained, the detector tip 11a has a high-position detector outlet. 11b and the U-shaped tube formed between the sample water outlet 5, the tip is kept immersed in the sample water and does not interfere with the next measurement by drying. An example of a glass electrode for pH measurement will be described as an example of a problem caused by drying. The glass electrode for pH measurement for measuring pH has a structure in which the reference electrode, which is a part of the structure, flows out to the sample liquid side at a minute flow rate through the microporous material. Therefore, if the dry state continues, the composition will precipitate in the internal liquid on the microporous material, causing clogging, and when sample water is supplied again and measurement should be started, normal operation is immediately started. The problem of not happening.
[0017]
The flow stabilization unit 2 configured as described above has a compact structure with a tube shape having an outer diameter of about 15 mm. However, the sample water overflowing the circulation section 4 flows from the periphery of the inner tube at the overflow outlet 6. Since it flows uniformly and is drained, it is approximately 200 to 300 ml / min. Even if the flow velocity fluctuates in this range, the water level of the overflowing portion does not change, and a good head water level is maintained. Therefore, the flow rate of the sample water introduced into the detector is regulated by this head difference. When the head difference is 50 cm, the flow rate at the sample water inlet 10 is 100 to 300 ml / min. Even if it fluctuates, the position of the detector is about 100 ml / min. Controlled. FIG. 4 shows the flow characteristics of each part of the flow stabilization unit.
[0018]
Moreover, if it is suddenly 200-300 ml / min. Even if there is a fluctuation exceeding 1, the sample water is not overflowed into the analyzer because it is protected by the outer pipe higher than the outlet part. In this embodiment, the inner tube is a tube having an outer diameter of 9 mm and an inner diameter of 6 mm, and the outer tube is a tube having an inner diameter of 11 mmφ and an outer diameter of 14 mm. Is not particularly limited, and can be arbitrarily selected as long as it is more compact than the head tank structure. Further, the structure of the inner pipe and the outer pipe is not limited to a circular pipe structure, and there is no particular limitation as long as it flows into the inner pipe from the entire periphery in the overflow portion.
[0019]
【The invention's effect】
According to the present invention, the flow rate stabilization unit placed in front of the water quality analyzer for monitoring the water quality such as boiler water is provided by the sample water inlet for introducing the sample water and the bottomed double tube communicating with the sample water inlet. In this way, the overflowing sample water is drained from the periphery of the upper part of the inner pipe, so that the head difference is kept good and a compact structure can be achieved. In addition, when the outlet from this flow rate stabilization unit is introduced into the detector of the analyzer, it is arranged at a position higher than the position of the drain of the detector, and the pipe from the sample water outlet to the water quality analyzer is connected to the detector. Since the sample water flows backward and the tip of the detector becomes soaked in the sample water, the sensor tip of the detector dries. It can be solved and has a high practical effect.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a flow of sample water in the vicinity of a conventional flow rate stabilization unit and a detector of a water quality analyzer.
FIG. 2 is an explanatory view showing the flow of sample water in the vicinity of another conventional flow stabilization unit and detector of the water quality analyzer.
FIG. 3 is an explanatory diagram showing the flow of sample water in the vicinity of the detector of the flow stabilization unit and the water quality analyzer of the present invention.
FIG. 4 is an explanatory diagram showing characteristics of the flow rate stabilization unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sample water inlet 2 Outer pipe 3 Inner pipe 4 Flow part 5 Sample water outlet 6 Overflow outlet 7 Drainage part 8 Flow rate stabilization unit 9 Water quality analyzer 10 Sample water inlet 11 Detector 11a Detector tip 11b Detector Exit

Claims (1)

Between the sample water inlet and the detector of the analyzer, the sample water inlet, and the flow channel with the gap between the outer tube and the inner tube as the flow channel of the bottomed double tube A sample water outlet provided in the outer pipe, an overflow outlet provided in the inner pipe further above the sample water outlet, and a drainage section using the inner wall gap of the inner pipe as a discharge path And a water quality analyzer in which a flow stabilization unit composed of an outer pipe higher than the overflow outlet is disposed, the position of the sample water outlet is higher than the position of the drain of the detector of the water quality analyzer And a pipe extending from the sample water outlet to the water quality analyzer, bypassing the position lower than the detector tip, and placing the detector outlet at a level higher than the position where the detector tip exists. A water quality analyzer characterized by being discharged after passing.

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