KR101164442B1 - Correcting apparatus for measuring apparatus of electrical conductivity of ultra pure water and general water - Google Patents

Abstract

The present invention is capable of measuring conductivity as well as ordinary water as well as ultrapure water in the resolution of 0.01 μS / cm, constant temperature and temperature change as necessary, thereby accurately correcting the conductivity measurement value. The present invention relates to a calibration device for ultrapure water and a conventional conductivity meter.
To this end, the present invention and the storage tank for storing the distilled water; A purifying device which receives distilled water from the storage tank and removes impurities and ions; Ultrapure water and ordinary water, characterized in that it comprises a constant temperature tank to receive the deionized water from which the impurities and ions have been removed to measure and correct the electrical conductivity of the deionized water and to change the temperature as needed. Provided is a calibration device for an conductivity meter.

Description

Corrective apparatus for measuring apparatus of electrical conductivity of ultra pure water and general water}

The present invention relates to a calibration device for an electrical conductivity measuring device of ultrapure water and ordinary water, and more particularly to accurately measure ultrapure water of 0.0548 μS / cm (= 54.8 nS / cm), which is an absolute value of electric conductivity as well as ordinary water. The present invention relates to a calibration device for ultrapure water and a conventional conductivity meter that can be calibrated.

Measures of water pollution include dissolved oxygen (DO), chemical oxygen demand (COD), pH, and electrical conductivity. Among these, electrical conductivity is based on the degree of inclusion of ionic contaminants in water. It is used as a representative measure of the degree of water pollution in that it provides direct information.

In addition, the conductivity is also information to determine whether seawater penetrates the coastal groundwater in the coastal region adjacent to the sea.

The electrical conductivity varies depending on the electrolyte concentration (the amount of ions) in the water, has an inverse relationship with resistance, and uses mho or S (Simens), which is an international unit system.

In addition, the electrical conductivity is affected by the temperature, and as the water temperature increases, the electrical conductivity increases, and on average, when the water temperature increases by 1 ° C, the electrical conductivity increases by about 2%.

Therefore, if the reference temperature is not set, there is a problem that the conductivity measurements cannot be compared with each other. Therefore, the temperature is set at 25 ° C. as the reference temperature, and the conductivity at different water temperatures is set at 25 ° C. using a predetermined temperature correction equation. Convert to electrical conductivity of.

The electrical conductivity varies depending on the type of water, ultrapure water is 0.0548 to 0.5 μS / cm, distilled water is 0.5 to 5 μS / cm, precipitation is 5.0 to 30 μS / cm, fresh water and ground water is 3 to 2000 μS / cm, Seawater ranges from 45,000 to 55,000 μS / cm and brine rises to approximately 100,000 μS / cm, depending on concentration.

According to the prior art, the electrical conductivity was measured by installing two electrodes on a water sample to be measured, supplying power to one electrode, and detecting the intensity of a signal reaching the other electrode.

1 is a view showing the internal configuration of an electrical conductivity measuring apparatus according to the prior art.

As shown in FIG. 1, an electric conductivity measuring apparatus according to the related art includes an output electrode 100, an input electrode 102, a rated voltage circuit 104, a current measuring circuit 106, a signal amplifying circuit 108, and It consists of a signal output calibration circuit 110.

When measuring the electrical conductivity, the output electrode 100 and the input electrode 102 are exposed to water, and then a voltage signal is supplied to the output electrode 100.

As a result, current flows from the output electrode 100 to the input electrode 102. The current measuring circuit 106 detects a current signal received by the input electrode 102, and the signal amplification circuit 108 and the signal output calibration circuit 110 amplify and process the current signal and transmit it to an external device.

In this case, the resistance in the aqueous solution may be calculated based on the voltage applied to the conductivity measuring sensor and the strength of the current detected by the input electrode 102, and thus, the conductivity in the inverse relationship with the resistance may be measured.

The ultrapure water is water that can be thought of as pure hydrogen and oxygen compounds by removing impurities such as salts and microorganisms in water through filtration, reverse osmosis, ion exchange, sterilization, and the like.

The ultrapure water is an aqueous solution in a state that does not conduct electricity because there is no ionic component is mainly used in ultra-precision manufacturing processes, such as LCD, semiconductors.

However, there is a need to develop a device capable of building a theoretical absolute value in the ultrapure water region.

In particular, the conventional calibration method in this area is difficult to prepare the conductivity standard solution, and was simply calibrated using an electrical resistance.

However, when calibrating the conductivity meter in the liquid state, the conventional method is an indirect calibration method.

Therefore, in order to accurately measure or calibrate near 0.0548 μS / cm (54.8 nS / cm), the absolute value of ultrapure conductivity, it is necessary to construct a related device capable of measuring resolution up to 0.01 μS / cm.

The present invention has been invented in view of the above, and in order to measure not only ordinary water but also water in the ultrapure water region, the electrical conductivity can be measured up to 0.01 μS / cm, becomes constant temperature, and changes the temperature as necessary. It is an object of the present invention to provide a calibration device for ultrapure water and a conventional conductivity meter which can accurately correct the conductivity measurement.

The above object is a storage tank for storing distilled water;

A purifier for receiving distilled water from the storage tank to remove impurities and ions;

Ultrapure water electricity comprising a constant temperature water tank for supplying the deionized water from which the impurities and ions have been removed to maintain a constant temperature for measuring and correcting the electrical conductivity of the deionized water, and for changing the temperature as necessary. Achieved by a calibration device for the conductivity meter.

Referring to the advantages and effects of the present invention by the above problem solving means as follows.

1. The conductivity can be measured up to 0.01 μS / cm, constant temperature, and temperature change as needed, so that it can be calibrated accurately in the ultrapure water region of a typical aqueous solution sample.

2. It is possible to check and correct the change of conductivity according to the temperature change.

1 is a conceptual diagram showing the configuration of an electrical conductivity measuring apparatus according to the prior art
2 is a conceptual diagram showing a calibration device of the ultrapure water and the conventional conductivity meter in accordance with an embodiment of the present invention
Figure 3 is a schematic diagram showing the internal configuration of a constant temperature water bath according to an embodiment of the present invention
Figure 4 is a block diagram showing the configuration for heating and cooling of the constant temperature water bath according to an embodiment of the present invention

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a conceptual diagram illustrating a calibration apparatus of an ultrapure water conductivity meter according to an embodiment of the present invention, and FIG. 3 is a schematic diagram showing an internal configuration of a constant temperature water bath according to an embodiment of the present invention, and FIG. A block diagram showing a configuration for heating and cooling a constant temperature water tank according to an embodiment of the present invention.

The present invention relates to a device for measuring the conductivity of ultrapure water, and more particularly, to a device capable of constructing a theoretical absolute value in the ultrapure water region.

Ultrapure water is pure water from which impurities such as salts and microorganisms in water are removed, and the electrical conductivity of the ultrapure water is 0.0548 to 0.5 µS / cm.

The present invention includes a storage tank (10) storing distilled water, a closed pump (12), a purifier (14), and a constant temperature water tank (16).

The closed pump 12 serves to transfer the water stored in the storage tank 10 to the purifier 14 at a constant pressure, and is blocked from external air.

The purifier 14 is a device including a filter and a cationic anion interphase eliminator so that the transferred water can be purified through a process such as filtration, reverse osmosis, ion exchange, and sterilization.

Here, since the configuration of the purifier 14 is a known technique for purifying raw water to produce ultrapure water, detailed description thereof will be omitted.

The constant temperature water tank 16 is a constant temperature according to the control signal of the precision thermometer 18 for measuring the internal water temperature, the temperature control unit 32 for maintaining a constant internal water temperature, and the temperature control unit 32 A heater and cooler 34 for heating and cooling the interior of the water tank 16 is included.

The precision thermometer 18 has a temperature resolution capable of measuring the internal water temperature at intervals of 0.01 ℃, the temperature controller 32 is a control signal to the heater and the cooler 34 in accordance with the detected temperature of the precision thermometer 18 By sending a constant temperature of the constant temperature water tank 16 can be adjusted.

In this case, the method of maintaining a constant temperature inside the constant temperature water tank 16 using the heater and the cooler 34 may be selected without limitation as long as it is a control method known in the art.

And, the temperature range in the constant temperature water tank 16 is preferably 10 ~ 50 ℃. This is because, in checking the compensation performance of the conductivity meter according to temperature and comparing and confirming with the fluctuation value of the conductivity sample, a wide temperature range is required, but the wide temperature range is very difficult in the design of the device. It is because it is preferable to limit to the range applicable to the surrounding environment.

When the distilled water is introduced into the closed interior space of the constant temperature water tank 16 through a filter and a cationic anion mixed ion remover in the purification device 14, the ultrapure water conductivity measuring apparatus according to the present invention is the same as the precision thermometer 18 is installed. The electric conductivity of the ultrapure water is measured and corrected at the position, and the external air is thoroughly shielded until the ultrapure water is set, and the closed circuit operation can be performed for a long time.

Inside the constant temperature water tank 16, a calibration device 28 for ultrapure water conductivity measuring instrument is installed.

The ultra pure water conductivity measuring instrument calibration device 28 is a measuring and indicating device for confirming that the conductivity of ultra pure water matches a target value, and includes two output electrodes 20, an input electrode 22, and an ultra pure electric conductivity measuring sensor ( 24a) and a current measurement circuit 26.

Looking at the measuring method of the ultra-pure electrical conductivity measuring instrument calibration device 28, after exposing the output electrode 20 and the input electrode 22 in an aqueous solution, and applying a voltage to the output electrode 20 output electrode 20 As the current flows from the input electrode 22 to the input electrode 22, the ultrapure electrical conductivity measuring sensor 24a measures the current flowing in the aqueous solution, and the current measuring circuit 26 detects the current signal received from the input electrode 22. do.

The signal amplification circuit and the signal output calibration circuit amplify and process the current signal and transmit the same to an external device.

At this time, the resistance in the water can be calculated through the strength of the voltage applied to the calibration device 28 for the ultrapure conductivity measuring instrument and the current detected by the ultrapure conductivity measuring sensor 24a. Conductivity can be measured.

In the constant temperature water tank 16, a thermometer 18, two output electrodes 20 and an input electrode 22, a conventional electrical conductivity measuring sensor (24b), the current measuring circuit 26 for a conventional electrical conductivity measuring device It further includes a calibration device (30).

Since the calibration device 28 for ultrapure conductivity measuring instrument and the calibration device 30 for normal conductivity measuring device have different conductivity measuring ranges (conductivity of ultrapure water is in the range of 0.0548 to 0.5 μS / cm, and normal conductivity is 0.5 to Range of 5 μS / cm), using sensors 24a and 24b with different measuring ranges, and measuring the area of the K factor, in which the area of the conductivity measuring sensors 24a and 24b is calculated as the distance between electrodes. Although there is a difference, the measuring method and the measuring principle are the same.

The calibration device 30 for a conventional conductivity meter is a measurement and indication device for confirming that the conductivity of ordinary water matches the target value, and is the same as the configuration and measurement method of the calibration device 28 for the ultrapure conductivity meter described above. Do.

Then, the distilled water is shielded from the external air until the distilled water is set to ultrapure water and is operated in a closed loop for a long time.

That is, the distilled water flows into the constant temperature water tank 16 through the filter and the cationic anion interphase eliminator from the storage tank 10, and then the deionized water from which the deionized water is removed reaches the set ultrapure water region. The device 14 (filter and deionizer) → constant temperature water tank 16 → storage tank 10 is continuously circulated.

Here, looking at the method of determining whether the distilled water has reached the ultrapure water region, the calibration device 28 for ultrapure water conductivity meter measures the electrical conductivity of distilled water introduced into the constant temperature water tank 16, the control unit ultrapure water conductivity meter The measured value is received from the calibration device 28 for comparison and it is determined whether the measured value is within a set range (electric conductivity value in the ultrapure water region).

That is, the controller continuously circulates the distilled water when the electric conductivity measurement value of the water is out of the setting range, and continues the circulation so as to fall within the setting range.

As described above, by constructing a device having excellent resolution by precise setting of components and precise design when configuring the measurement circuit, it is possible to measure not only ordinary water but also water in an ultrapure water region.

10: storage tank 12: hermetic pump
14 purification device 16 constant temperature water tank
18: thermometer 20: output electrode
22: input electrode 24a: ultrapure electrical conductivity measurement sensor
24b: Normal conductivity sensor
26: current measurement circuit 28: calibration device for ultrapure electrical conductivity measuring instrument
30: calibration device for normal conductivity meter
32: temperature control part 34: heater and cooler

Claims (5)

A storage tank 10 storing distilled water;
Purifier 14 for removing the impurities and ions by receiving distilled water from the storage tank;
A constant temperature water tank (16) capable of keeping the temperature constant and changing the temperature to receive and supply deionized water from which the impurities and ions have been removed to measure and correct the electrical conductivity of the deionized water;
Including;
It is installed inside the constant temperature water tank and receives the measurement value from the ultra pure water conductivity measuring device calibration device 28 for measuring the electrical conductivity of distilled water, and the ultra pure water conductivity measuring device calibration device 28, the measured value is ultra pure water And a control unit for determining whether the area is within a preset setting range, and storing the distilled water in the storage tank 10, the purifying device 14, and the constant temperature water tank 16 until the measured value is within the setting range. Calibrating device for ultrapure water and electric conductivity meter, characterized in that the circulation.
delete The method according to claim 1, The constant temperature water tank 16 is a thermometer 18 for precisely measuring the water temperature, a temperature control unit 32 for adjusting the temperature to maintain the water temperature constant, and the temperature control unit 32 Calibration device for ultra-pure water and electric conductivity meter, characterized in that it comprises a heater and cooler 34 for heating or cooling water in accordance with the control signal of.
The apparatus of claim 1, further comprising a sealed pump for transferring the deionized water from the storage tank to the purification device.
2. The thermostat (18), two output electrodes (20) and input electrodes (22), typically inside the thermostatic bath (16), to determine whether ultrapure water and normal conductivity match target values. Calibration device for a ultra-pure water and a conventional conductivity meter, characterized in that it further comprises a calibration device for a conventional conductivity meter composed of an electrical conductivity measurement sensor (24b), a current measurement circuit (26).

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