JPS6124927Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a device for measuring the ratio of dissolved oxygen contained in a liquid to a saturation value, and in particular provides a device that is convenient to carry, accurately and quickly measures the dissolved oxygen saturation rate. It is in.

Conventionally, to determine the dissolved oxygen saturation rate, the dissolved oxygen concentration (Amg/) in a liquid is measured, and the dissolved oxygen concentration (Aomg/) in a pure liquid at the same temperature as the liquid sample is calculated from a constant table. Using this saturation value as a standard, Ds=A/Ao×100 (%) is calculated, and Ds is taken as the dissolved oxygen saturation rate.

It is generally known that the dissolved oxygen saturation value changes depending on the temperature of the liquid and the impurities contained in the liquid. For example, taking water as an example, in pure water at 20°C the salinity is 8.84mg/, while at 10°C and 30°C the salinity is 10.92 and 7.53mg/, respectively, and the salinity is 15000mg/, which is close to seawater. If chloride ions are included, at temperatures of 10, 20, and 30℃.
Changes to 9.23, 7.54, 6.41mg/. The amount of change in dissolved oxygen saturation value per 100 mg of chloride ion varies depending on the concentration level of chloride ion and temperature.
It varies in the range of 0.0074 to 0.0153 mg/. That is,
It can be seen that temperature and salinity significantly affect dissolved oxygen saturation values.

Contaminants in liquids are often mixed in a complex manner, and it is difficult to estimate the saturation value using a single component and temperature as parameters. Therefore, by actually measuring the dissolved oxygen saturation value (Ao'mg/) that the liquid reaches when it comes into contact with air at the site of dissolved oxygen measurement, and finding Ds' = A/Ao' x 100 (%), the theoretical The Ds estimated from the value does not match Ds', and deviations often occur.

Dissolved oxygen concentration tends to change due to fluctuations, temperature changes, pressure changes, contact with outside air, etc., so measurements are performed in an environment where liquid exists, that is, at the sample collection site. It is difficult to accurately measure various factors that affect temperature, impurities, etc., and even if temperature, chloride ion concentration, etc. can be measured, the dissolved oxygen saturation value can be calculated from these measured values proportionally from a table of constants. It must be read based on proportion, and it is difficult to ensure accuracy.

In recent years, it has been used as one of the pollution indicators of public water bodies such as rivers, lakes, and sea areas, for the management of biological treatment processes such as sewage, human waste, and industrial wastewater, for monitoring the water quality of effluent water, for the water quality management of fish ponds, and for fermentation tanks. Dissolved oxygen is widely measured in industry as an operational indicator.

Oxygen sag curves showing the degree of pollution of water bodies, rivers,
Dissolved oxygen saturation rate is indispensable when predicting the appearance of oxygen consumption and deoxygenation in water in sea areas, deriving the reaeration coefficient of rivers, etc., determining the oxygen transfer coefficient, and the relationship between the dissolved oxygen saturation value, etc. used and its value must be accurate. For the reasons mentioned above, it is desirable to measure the dissolved oxygen saturation value of the same sample at the same time at the site of dissolved oxygen measurement.
That is, there has been a strong desire for an apparatus that can be freely carried to the site of dissolved oxygen measurement and that can accurately measure the dissolved oxygen saturation rate.

In addition, galvanic or polar chromatographic membrane electrodes are commonly used to measure dissolved oxygen, but since the thickness of the membrane through which oxygen molecules permeate and the oxygen permeability coefficient affect the diffusion current value, A current value is determined for a liquid whose dissolved oxygen concentration is known, and a so-called proportionality constant setting operation is performed in which the indicated value is adjusted to the known concentration, that is, the device is calibrated. This procedure generally uses water saturated with dissolved oxygen at 20°C, and is usually calibrated in advance in the laboratory to continue measuring dissolved oxygen over a long period of time. However, in reality, suspended particles and pollutants that coexist in water adhere to the diaphragm, changing the actual membrane thickness and oxygen permeability coefficient. Therefore, it is often necessary to calibrate the dissolved oxygen meter at the measurement site using reference water whose dissolved oxygen concentration is known. From this point of view, there has been a demand for a portable device that can easily adjust the dissolved oxygen saturated reference water at the measurement site.

It usually takes a long time to prepare dissolved oxygen saturated liquids. For this reason, it consumes a large amount of electricity, is difficult to make small and portable, and requires a long time to saturate the sample in the field, making it impractical.

With these needs in mind, the inventors conducted extensive research into reducing the time required to complete dissolved oxygen saturation, and as a result, they were able to reach the saturation value in an extremely short time by introducing microbubbles in a vortex-like manner. We discovered that it is possible to achieve this by easily saturating the sample with oxygen to form a dissolved oxygen saturated liquid using a small and lightweight device that can be carried at the site of dissolved oxygen measurement, and by signal processing the dissolved oxygen saturation value and the dissolved oxygen measurement value to obtain Ds. =A/Ao′×100
We have devised a device that calculates (%) and displays it on a display.

That is, the present invention includes a liquid introduction port that is sealed with a removable stopper, an air introduction device, a device that communicates with the air introduction device and blows out air from the air introduction device as fine bubbles, and the air bubbles. a container equipped with a stirrer that creates a whirlpool, a container having a liquid to be measured outlet and a dissolved oxygen concentration detector insertion port and equipped with a stirrer, and a communication pipe with a switching pot that communicates both the containers. , a dissolved oxygen concentration detector that is attached to the dissolved oxygen concentration detector insertion port, a computing unit that stores and calculates the measured value by the detector, and a display that displays the computed value of the computing unit. This is an oxygen saturation rate measuring device.

Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings.

In the figure, 1 is an oxygen-saturated liquid adjustment container with a volume of about 200 to 300 ml that also serves as sample collection, including a sample introduction port 22, an overflow port 5, a drain port 10, and a removable stopper 14.
has. The container contains an electromagnetic stirrer 16 and a spherical bubble generator 17 with fine holes, the former operated by the electromagnetic stirrer 13 and the latter connected to the air pump 12 via a tube 18. A sample introduction port 22 connected to the three-way pot 4 is connected to a sample introduction pipe 33 through a sample collection pump 3. 34, 35
is a connecting pipe, and 23, 24, and 25 are communication ports in the three-way socket 4.

2 is a dissolved oxygen measuring container with a volume of about 100 to 150 ml, which has an overflow port 19, a sample outlet 20, and a sample inlet 2.
1. Has a dissolved oxygen concentration detector insertion port 42. An electromagnetic stirrer 8 is provided inside the container 2, and the stirrer 8 is interlocked with an electromagnetic stirrer 11. Further, the sample introduction port 21 communicates with the drain port 10 of the container 1 via the three-way pot 7 and the communication tube 6. 26,
27, 28 are three-way communication ports, 36, 37,
38 indicates a connecting pipe.

Furthermore, 9 is a three-way pot, and its communication port 29 is connected to the outlet 20 of the container 2 via a connecting pipe 39,
The communication port 30 is connected to the overflow port 19 via a connecting pipe 40, and the communication port 31 is connected to a T-shaped discharge pipe 32 via a connecting pipe 41. Further, the overflow port 5 of the container 1 is connected to the discharge pipe 32 via a connecting pipe 15.

43 is a dissolved oxygen concentration detector attached to the detector insertion port 42 of the container 2, and 44 is an oxygen electrode including an anode and a cathode. 45 is a computing unit, and the detector 4
3. Store and calculate the measured values. A display 46 displays the calculated value of the calculator 45.

Furthermore, the volumes of the containers 1 and 2 are approximately 2:1.
Good. Since the electrode 44 is inserted into the container 2,
The effective internal volume of the container is further reduced by half. The communication tube 6 forms a siphon, and the container 2 is placed at a lower level than the container 1.

Further, the sample collection pump 3 may be of any type such as a plunger type, a spiral type, a turbine type, a gear type, an electromagnetic type, or a diaphragm type, and the plunger type is preferable for portable use. Even if a sample is sent into a container using a pump, if the first 50 to 100 ml is allowed to overflow and drain, the dissolved oxygen concentration will be the same as that of the sample and will show a constant value. Air pumps may be of the compressor type, blower type, diaphragm type, etc.
For portable use, a diaphragm pump is preferred.

Further, the liquid in the container may be stirred by any method such as a method of rotating a stirring blade or an electromagnetic stirring method. Preferably, the electromagnetic stirring method is excellent for portable use.

The most important point of this invention is to shorten and speed up the time to saturate the liquid to be measured with oxygen. For example, the oxygen saturation rate using a spherical bubble generator made of semi-molten glass,
The saturation speed when flowing a liquid or generating bubbles in a vortex is that in the former case it takes 20 minutes to saturate, whereas when the bubbles are made to flow relatively in a vortex. Oxygen saturation time is shortened to 5 minutes, and by using a diaphragm pump, the power required to drive these devices is small, allowing for portability and miniaturization.

To make bubbles flow in a whirlpool, there are two methods: rotating an electromagnetic stirrer to stir the liquid, or rotating a spherical bubble generator to generate bubbles in a whirlpool, the latter of which is preferred by rotating the bubbler. Good method. During aeration, there is a risk that contaminants in the air may transfer to and dissolve in the liquid in the container, so it is preferable that the incoming air be passed through a container filled with pure water and cleaned in advance. If pure water or distilled water is introduced into the container 1 instead of the sample and operated in the same manner, the dissolved oxygen saturation reference water can be adjusted, thereby making it possible to calibrate the oxygen electrode at the measurement site.

Now, when the switch (not shown) of the pump 3 is turned ON to operate the pump 3, a series of relays connect the three-way pump 4 to the communication port 23,
25, and the three-way socket 7 has communication ports 26 and 28.
However, the three-way pot 9 is further switched so that the communication ports 30 and 31 are in communication with each other, and the sample flows into the container 1 from the sampling point through the pipe 33. When the liquid level in the container 1 rises, part of the sample is discharged through the overflow port 5, and part of the sample is transferred to the container 2 through the communication pipe 6, and as the liquid level in the container rises, it is discharged through the overflow port 19. It is discharged into pipe 32.

When such a situation is reached, the electromagnetic stirrer 1
1 to operate the stirrer 8, and when the differential value of the diffusion current of the oxygen electrode 44 with respect to the amount of dissolved oxygen becomes zero, the calculator 45 memorizes that value and at the same time the switch of the pump 3 is turned off. OFF), a series of relays are activated and Kotoku 7 is connected to communication ports 27 and 2.
In the container 8, the communication ports 29 and 31 communicate with each other, and the liquid in the container 2 is discharged. At the same time, the switch (not shown) of the pump 12 is turned on, the air pump 12 and the stirrer 16 rotate, and the spherical bubble generator 1
The microbubbles generated from 7 spread into the container 1 in the form of a vortex, and oxygen rapidly dissolves in the liquid. When a timer (not shown) reaches the set time, pump 12 is switched off and air pump 1 is switched off.
2. The stirrer 16 is stopped, the air bubbles in the container 1 disappear rapidly, and a series of relays are activated to open the communication ports 24 and 25 in the pot 4 and the communication port 2 in the pot 7.
6 and 28, the communication ports 30 and 31 of the pot 9 communicate with each other, and the dissolved oxygen saturated liquid in the container 1 moves to the container 2,
When the differential value of the diffusion current flowing through the oxygen electrode 44 becomes zero, the arithmetic unit 45 calculates the dissolved oxygen saturation rate, and the result is displayed on the display 46.

As described above, the present invention is a device that is sealed with a removable stopper, and that is connected to a liquid to be measured inlet, an air introduction device, and the air introduction device, and that blows out air from the air introduction device as fine bubbles. and a container equipped with a stirrer that causes the bubbles to form a whirlpool, a container having a liquid to be measured outlet and a dissolved oxygen concentration detector insertion port, and also equipped with a stirrer, and a switching pot for connecting both the containers. a communication pipe, a dissolved oxygen concentration detector attached to the dissolved oxygen concentration detector insertion port, and a computing unit that stores and calculates the measured value by the detector;
Since it has a display that displays the calculated values of the arithmetic unit, it is small and lightweight, making it convenient to carry.

Furthermore, since air is supplied to the liquid to be measured to make it a dissolved oxygen saturated liquid, the dissolved oxygen saturation rate also becomes more accurate. Furthermore, since a dissolved oxygen saturated liquid can be generated in a short time using a bubble generator, measurements can be carried out quickly.

[Brief explanation of the drawing]

The figure is a schematic side view of the dissolved oxygen saturation rate measuring device according to the present invention. 1... Container, 2... Container, 6... Communication pipe, 8...
... Stirrer, 14 ... Stopper, 17 ... Air introduction device, 2
0...Measurement liquid outlet, 22...Measurement liquid inlet, 42...Dissolved oxygen concentration detector insertion port, 43...
...Dissolved oxygen concentration detector, 45...Arithmetic unit, 46...
…display.

Claims (1)

[Scope of utility model registration request] A liquid to be measured inlet that is sealed by a removable stopper, an air introduction device, a device that communicates with the air introduction device and blows out air from the air introduction device as fine bubbles, and a device that makes the bubbles form a vortex. a container equipped with a stirrer; a container having a liquid to be measured outlet and a dissolved oxygen concentration detector insertion port and equipped with a stirrer;
A communication pipe with a switching point connecting the two containers, a dissolved oxygen concentration detector attached to the dissolved oxygen concentration detector insertion port, a computing unit for storing and computing the measured value by the detector, and the computing unit. Dissolved oxygen saturation rate measuring device consisting of a display that displays the calculated value of.