Dilution device and method for measuring water quality

Abstract

A dilution device for measuring water quality that can control the dilution ratio with high precision. [Solution] A dilution device for water quality measurement for preparing sample water by diluting a stock solution with dilution water, the dilution device for water quality measurement having a container 10, a stock solution supply section for supplying stock solution to the container, a dilution supply section for supplying dilution water to the container 10, a circulation section for circulating the liquid in the container, an outflow section for draining the liquid in the container, and a pressure sensor 9 for detecting the water level in the container, wherein the outflow section is equipped with a pump 14, and the dilution device for water quality measurement is capable of draining liquid from the container 10 by gravity when the pump 14 is stopped.

Description

[Technical field]

[0001] The present invention relates to a dilution device for measuring water quality, and more particularly to a dilution device for measuring water quality by diluting an undiluted solution.The present invention also relates to a dilution method using the dilution device for measuring water quality. [Background technology]

[0002] As a technology for automatically measuring the residual chlorine concentration in water, a batch-type automatic continuous residual chlorine concentration measuring device is known, which measures the residual chlorine concentration in water by absorptiometry using N,N-diethyl-1,4-phenylenediamine reagent (DPD reagent). The residual chlorine concentration that can be measured by this device is 8 mg / L or less. Therefore, this device is not suitable for measuring high concentration ranges above 8 mg / L.

[0003] Patent Document 1 describes a water quality measurement dilution device capable of quantifying high concentrations of residual chlorine, which includes a dilution device that prepares sample water containing raw water and dilution water, and a residual chlorine concentration measuring device that measures the residual chlorine concentration of the sample water, wherein the dilution device is equipped with a container in which the sample water is stored, a first liquid level detection unit that detects a first liquid level in the container, a second liquid level detection unit that detects a second liquid level in the container, a raw water injection unit that injects the raw water into the container until the first liquid level detection unit detects the first liquid level, and a dilution water injection unit that injects the dilution water into the container to dilute the raw water until the second liquid level detection unit detects the second liquid level.

[0004] In the dilution device for water quality measurement of Patent Document 1, the dilution device dilutes raw water and, if necessary, dilutes the raw water again to prepare sample water, which is then transferred to a residual chlorine concentration measuring device via a sample water storage section and used to measure the residual chlorine concentration. In this water quality measuring device, the raw water is diluted once or twice or more times. By diluting the raw water twice or more times, high concentration raw water can be sufficiently diluted. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2023-87160 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the dilution device for measuring water quality in Patent Document 1, if a capacitance sensor or optical sensor is used as the liquid level detection unit, errors can occur in the liquid level detection due to dirt on the dilution container or water droplets running down the walls of the dilution container, resulting in fluctuations in the dilution concentration.

[0007] Patent Document 1 also describes the use of a pressure type liquid level sensor to detect the water level. However, in Patent Document 1, when measuring raw water, raw water in the raw water tank is poured into the container from above until the liquid level detector detects the liquid level.

[0008] In this way, when raw water is supplied from above, the liquid level inside the container fluctuates as the raw water falls inside the container. When the liquid level fluctuates in this way, pressure fluctuations occur, so even if a pressure-type liquid level sensor is used as in Patent Document 1, an error occurs in the detected water level.

[0009] An object of the present invention is to provide a dilution device and a dilution method for water quality measurement that can control the dilution ratio with high precision. [Means for solving the problem]

[0010] The dilution device for water quality measurement of the present invention is a dilution device for water quality measurement for preparing sample water by diluting a stock solution with dilution water, and comprises a container, a stock solution supply section for supplying stock solution to the container, a dilution water supply section for supplying dilution water to the container, a circulation section for circulating the liquid in the container, an outflow section for draining the liquid in the container, and a pressure sensor for detecting the water level in the container, and the outflow section is equipped with a pump, and when the pump is stopped, gravity is used to drain the liquid from the container.

[0011] In one aspect of the present invention, the circulation section performs circulatory water supply by the pump of the outflow section.

[0012] The dilution method of the present invention is a method for preparing sample water by diluting a stock solution with dilution water using the dilution device for water quality measurement of the present invention, and includes a stock solution introducing step of introducing a first specified amount of stock solution into the container, a dilution water introducing step of introducing a second specified amount of dilution water into the container, a stirring step of circulating and stirring the liquid in the container, and a removal step of removing the diluted liquid from the container. the concentrate introducing step includes a step of introducing an amount of concentrate in excess of the first specified amount into the container, a pump discharge step of operating the pump to discharge a portion of the excess amount from the container, and then a gravity discharge step of stopping the pump and allowing the concentrate in the container to flow out by gravity so that the amount of concentrate in the container detected by the pressure sensor becomes the first specified amount.

[0013] In one aspect of the dilution method of the present invention, after the original liquid introducing step is performed, the residual liquid in the circulation section is discharged outside the dilution apparatus for water quality measurement, and then the dilution water introducing step is performed.

[0014] In one aspect of the dilution method of the present invention, after the above-mentioned stock solution introduction step, dilution water introduction step, and stirring step are performed, a liquid drainage step is performed in which the liquid volume in the container is drained to the first specified volume, and then dilution water is introduced into the container to perform a second dilution step.

[0015] In one aspect of the dilution method of the present invention, after the draining step, residual water is discharged from the circulation section before the dilution water is introduced. Effect of the Invention

[0016] According to the dilution device and dilution method for water quality measurement of the present invention, when preparing diluted sample water by mixing a specified amount of stock solution and dilution water in a container, the amount of liquid in the container is detected by a pressure sensor. In the dilution method of the present invention, after introducing an excess of stock solution into the container compared to the specified amount, first, most of the excess is discharged by a pump, and then the remaining excess is drained by gravity to store the specified amount of stock solution in the container.

[0017] When the excess is drained by gravity in this way, the liquid level in the container does not fluctuate due to pump vibration, and the water level is detected with high accuracy by the pressure sensor, so that the specified amount of the concentrate can be stored in the container with high accuracy. Therefore, the concentrate can be diluted at a highly accurate dilution ratio.

[0018] Furthermore, by discharging most of the excess with a pump, the discharge time is shortened compared to discharging all of the excess by gravity. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a configuration diagram of a dilution device for water quality measurement according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram of a water quality measurement process in the dilution device for water quality measurement of FIG. 1. [Diagram 3] FIG. 2 is an explanatory diagram of a water quality measurement process in the dilution device for water quality measurement of FIG. 1. [Figure 4] FIG. 2 is an explanatory diagram of a water quality measurement process in the dilution device for water quality measurement of FIG. 1. [Diagram 5] FIG. 2 is an explanatory diagram of a water quality measurement process in the dilution device for water quality measurement of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment will be described with reference to the drawings. Fig. 1 is a configuration diagram of a dilution device for measuring water quality according to an embodiment.

[0021] A stock solution supply unit consisting of a pipe 1, a solenoid valve 2, and a pipe 3 is connected to the top of the container 10 so as to supply stock solution into the container 10. Also, a dilution water supply unit consisting of a pipe 4, a solenoid valve 5, and a pipe 6 is connected to the top of the container 10 so as to supply dilution water into the container 10.

[0022] A communication port (not shown) that connects the inside of the container 10 to the atmosphere is provided at the top of the container 10. When liquid is supplied to or discharged from the container 10, air flows in and out of the container 10 through the communication port.

[0023] A pressure sensor 9 for detecting the water level in the container 10 is provided at the lower part of the container 10 (the bottom part in this embodiment).

[0024] In order to discharge or circulate the liquid in the container 10, an outflow section consisting of a pipe 11, a solenoid valve 12, a pipe 13, a pump 14 and a pipe 15 is connected to the bottom of the container 10.

[0025] The pump 14 is configured to send water from the pipe 13 to the pipe 15 when it is operating, and to connect the pipes 13 and 15 to each other (to allow water to flow) when it is stopped.

[0026] The end of the pipe 15 branches into pipes 16, 20, and 23. The pipe 16 constitutes a circulation section and is connected to the upper part of the container 10 via a solenoid valve 17 and a pipe 18, and returns the liquid in the container 10 to the upper part and circulates it.

[0027] The pipe 20 is connected to a pipe 22 via an electromagnetic valve 21, and these constitute an extraction section for extracting the diluted analysis sample water.

[0028] The pipe 23 is connected to a pipe 25 via an electromagnetic valve 24, and these constitute a discharge section for discharging the liquid in the container 10 and each pipe to the outside of the system.

[0029] Each step for preparing diluted sample water using the thus configured dilution apparatus for water quality measurement will be described below.

[0030] [Initial drainage process] First, the residual liquid remaining in the water quality measurement dilution device from the previous dilution operation is discharged. To discharge the residual liquid, the solenoid valves 12 and 24 are opened, the other solenoid valves are closed, and the pump 14 is operated (hereinafter sometimes referred to as ON). As a result, the residual liquid in the container 10 and between the pipes 11 to 15 is discharged through the pipes 23 and 25.

[0031] Next, pump 14 is stopped (hereinafter sometimes referred to as OFF), solenoid valves 17 and 24 are opened, and the other solenoid valves are closed.

[0032] [Still solution introduction process] To prepare sample water by diluting the stock solution with dilution water at a specified ratio, first, the stock solution is stored in the container 10 to a water level H1. Hereinafter, the amount of liquid at the water level H1 may be referred to as the first specified amount.

[0033] In this case, solenoid valve 2 is opened, the other solenoid valves are closed, and pump 14 is turned OFF. Solenoid valve 2 is opened for a predetermined time so that the water level in container 10 is higher than H1, and the stock solution is introduced. Then, solenoid valves 12 and 24 are opened, the other solenoid valves are closed, pump 14 is turned ON, and after the water level in container 10 is lowered to near H1, pump 14 is turned OFF. At this time, solenoid valves 12 and 24 are left open. This causes the liquid to flow out of container 10 by gravity. In this case, since pump 14 is turned OFF, container 10 does not vibrate, and the liquid level in container 10 does not sway.

[0034] When the water level detected by the pressure sensor 9 reaches H1, the solenoid valve 12 is closed, so that the concentrate is stored in the container 10 precisely at the water level H1 (FIG. 2).

[0035] As described above, pump 14 is turned ON to perform pumping until the water level approaches H1, and then pump 14 is turned OFF to perform gravity discharge, in which the liquid flows out of container 10 by gravity. In this way, liquid is discharged from container 10 by pump 14 until the water level approaches H1, so that drainage is speeded up. During gravity discharge, the liquid level in container 10 does not fluctuate due to vibrations propagated from pump 14, and the water level detected by pressure sensor 9 is highly accurate.

[0036] The outflow speed during gravity outflow is slower than that during pump discharge with pump 14 turned on, and the drop in the water level in container 10 is slow. Therefore, when the water level in container 10 drops to H1, solenoid valve 12 can be closed reliably.

[0037] [Draining the circulation piping] After the above-mentioned raw solution introduction step, solenoid valves 17 and 24 are opened, the other solenoid valves are closed, pump 14 is turned off, and the liquid between pipes 18 to 16 is discharged through pipes 23 and 25.

[0038] [Dilution process] Thereafter, solenoid valve 5 is opened, the other solenoid valves are closed, pump 14 is turned OFF, and dilution water is introduced into container 10 up to water level H2 (FIG. 3). Next, solenoid valves 12 and 17 are opened, the other solenoid valves are closed, pump 14 is turned ON, and the liquid in container 10 is circulated and stirred through pipes 11, 13, 15, 16, and 18 (FIG. 4).

[0039] If the volume of the original solution introduced into container 10 is V1 and the volume of the dilution water introduced into container 10 (second specified amount) is V2, sample water diluted with the original solution by a factor of (V2+V1) / V1 (hereinafter referred to as the first diluted sample water) is prepared by the above-mentioned first dilution step (first dilution step).

[0040] If the first diluted sample water is a 10-fold dilution of the original solution, a similar second 10-fold dilution step (second dilution step) is performed to prepare a second diluted sample water that is 100-fold diluted, and a similar third 10-fold dilution step (third dilution step) is performed on the second diluted sample water to prepare a third diluted sample water that is 1000-fold diluted.

[0041] In addition, to perform the second, third or higher dilution step (hereinafter sometimes referred to as the nth dilution step), a discharge step is performed in which the (n-1)th diluted sample water prepared in the (n-1)th dilution step in the container 10 is discharged by pumping and gravity discharge to the water level H1.

[0042] In this discharge process, initially, solenoid valves 12 and 24 are opened, the other solenoid valves are closed, and pump 14 is turned ON to perform pump discharge, and when the water level approaches H1, solenoid valves 12 and 24 are left open and pump 14 is turned OFF to perform gravity discharge, discharging the liquid in pump container 10 by gravity. In the case of gravity discharge, the liquid level in container 10 does not fluctuate, so the residual water volume can be determined to be water level H1 with high accuracy.

[0043] After the level of the (n-1)th diluted water sample in the container 10 is lowered to H1 as described above, the solenoid valves 17 and 24 are opened, the other solenoid valves are closed, the pump 14 is turned off, and the (n-1)th diluted water sample remaining between the pipes 18 to 16 is discharged via the pipes 23 and 25. Thereafter, dilution water is introduced into the container 10 up to the water level H2, and circulated and stirred to produce the nth diluted water sample.

[0044] [Removal process] To remove the diluted water sample from the container 10 after the above dilution step, the solenoid valves 12 and 21 are opened, the other solenoid valves are closed, the pump 14 is turned on, and the diluted water sample is removed via the pipes 11, 13, 15, 20, and 22 (FIG. 5).

[0045] <Concentrate, water for dilution> The present invention is suitable as a dilution device for measuring the residual chlorine concentration in a stock solution, and examples of such stock solutions include, but are not limited to, CIP cleaning solutions in beverage and food manufacturing plants, food sterilizing solutions, cooking utensil sterilizing solutions, etc. However, the water quality measurement dilution device of the present invention can also be used as a dilution device for measuring components other than residual chlorine.

[0046] The dilution water may be, but is not limited to, tap water treated with activated carbon, pure water, ultrapure water, or the like.

[0047] <Container> The container is preferably cylindrical, but may also be rectangular. In the case of a cylindrical container, the height of the container is preferably 3 to 30 times, and more preferably 5 to 10 times, the diameter of the bottom surface.

[0048] <Pressure sensor> The pressure sensor is not particularly limited as long as it can detect the water level inside the container 10, and various commercially available products can be used.

[0049] The above-described embodiment is merely an example of the present invention, and the present invention may be embodied in other forms than those described above. [Explanation of symbols]

[0050] 2,5,12,17,21,24 Solenoid valve 9. Pressure Sensor 10 containers 14 Pump

Claims

1. A dilution device for water quality measurement for preparing sample water by diluting a stock solution with dilution water, A container; A raw liquid supply unit that supplies a raw liquid to the container; A dilution water supply unit that supplies dilution water to the container; A circulation unit that circulates the liquid in the container; An outlet for discharging liquid from within the container; a pressure sensor for detecting the water level in the container; A dilution device for water quality measurement having The outflow section is provided with a pump, and the outflow section is capable of causing the liquid to flow out of the container by gravity while the pump is stopped. This dilution method comprises: A stock solution introducing step of introducing a first specified amount of stock solution into the container; a dilution water introducing step of introducing a second specified amount of dilution water into the container; a stirring step of circulating and stirring the liquid in the container; a removing step of removing the diluted liquid from the container; It has The step of introducing the concentrate comprises the steps of: introducing an amount of concentrate in excess of the first specified amount into the container; a pump discharge step of discharging a portion of the excess from the container by operating the pump; a gravity discharge step of stopping the pump and discharging the concentrate in the container by gravity so that the amount of concentrate in the container detected by the pressure sensor becomes the first specified amount; The dilution method comprising the steps of:

2. 2. The dilution method according to claim 1, wherein after the step of introducing the concentrate is performed, the residual liquid in the circulation section is discharged to the outside of the dilution apparatus for water quality measurement, and then the step of introducing the dilution water is performed.

3. After the step of introducing the stock solution, the step of introducing the dilution water and the step of stirring are performed, a step of draining the liquid so that the amount of liquid in the container becomes the first specified amount is performed; 3. The method according to claim 2, further comprising the step of: introducing dilution water into said vessel to carry out a second dilution step.

4. 4. The dilution method according to claim 3, further comprising the step of: discharging residual water from said circulation section after said draining step and before introducing said dilution water.

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