KR102564915B1 - Calibration device and calibration method of NO2 sensor for radio sonde - Google Patents

Abstract

The present invention relates to calibration of NO ₂ sensors, and more particularly, to a calibration device and method for measuring NO ₂ concentration using a radiosonde in the troposphere of 10 km or less. To this end, NO ₂ CRM (200) for receiving NO ₂ certified reference material; an air unit 210 in which air is accommodated; a gas mixer 220 connected to the NO ₂ CRM 200 and the air unit 210 and controlling a concentration of NO ₂ by adjusting a mixing ratio of NO ₂ and air; A flow rate control unit 230 connected to the gas mixer 220 to control the flow rate of gas; a test chamber 110 in which an NO ₂ sensor for a radiosonde is installed and supplied with gas from a flow rate controller 230; a weather chamber 100 in which the test chamber 110 is accommodated and capable of temperature control; a temperature sensor 120 for measuring the temperature of the test chamber 110; and a controller 260 calculating a calibration value _of the NO ₂ sensor based on the temperature, concentration, and flow rate of the temperature sensor 120 and the output of the NO ₂ sensor. device is provided.

Description

Calibration device and calibration method of NO2 sensor for radio sonde}

The present invention relates to calibration of NO ₂ sensors, and more particularly, to a calibration device and method for measuring NO ₂ concentration using a radiosonde in the troposphere of 10 km or less.

In general, measuring the concentration of nitrogen dioxide (NO ₂ ) in the atmospheric environment in the troposphere below 10 km is an essential element for monitoring the global environment. Conventionally, a satellite or aerial measurement method has been used to measure the concentration of NO ₂ . However, this method has disadvantages in that it is difficult to know the vertical distribution of the NO ₂ concentration and the accuracy is low.

In order to solve these disadvantages, it has been proposed to install a NO ₂ sensor on a radio sonde and make it visible, but it has not yet been put into practical use.

As part of such research and development, in order to develop a radiosonde in which an NO ₂ sensor is installed, calibration of the NO ₂ sensor must be preceded. However, even if the NO ₂ sensor is calibrated under atmospheric pressure conditions on the ground, when exposed to a high meteorological environment, the measured value is affected by temperature/flow velocity/atmospheric pressure, making the ground calibration value invalid.

Therefore, it is necessary to implement a high-level meteorological environment on the ground and calibrate the NO ₂ sensor in the implemented high-level meteorological environment.

1. Republic of Korea Patent Publication No. 10-2013-0076232 (sensor device and cooling facility performance evaluation device including the same), 2. Republic of Korea Patent Publication No. 10-2020-0004637 (Performance evaluation system and method of environmental measurement sensor).

Therefore, the present invention has been made to solve the above problems, and the problem to be solved by the present invention is to implement a high-rise weather environment on the ground, and a radio capable of calibrating the NO ₂ sensor in the implemented high-rise weather environment. It is to provide a calibration device and a calibration method for a NO ₂ sensor for a sonde.

Another object of the present invention is to provide a calibration device and a calibration method for a NO ₂ sensor for a radiosonde that enables accurate calibration by setting temperature, flow rate, and atmospheric pressure as environmental variables of a high-rise meteorological environment.

However, the technical problems to be achieved in the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clear to those skilled in the art from the description below. You will be able to understand.

In order to achieve the above technical task, NO ₂ CRM (200) for accommodating certified reference materials NO ₂ ; an air unit 210 in which air is accommodated; a gas mixer 220 connected to the NO ₂ CRM 200 and the air unit 210 and controlling a concentration of NO ₂ by adjusting a mixing ratio of NO ₂ and air; A flow rate control unit 230 connected to the gas mixer 220 to control the flow rate of gas; a test chamber 110 in which an NO ₂ sensor for a radiosonde is installed and supplied with gas from a flow rate controller 230; a weather chamber 100 in which the test chamber 110 is accommodated and capable of temperature control; a temperature sensor 120 for measuring the temperature of the test chamber 110; and a controller 260 calculating a calibration value _of the NO ₂ sensor based on the temperature, concentration, and flow rate of the temperature sensor 120 and the output of the NO ₂ sensor. device is provided.

In addition, air contains nitrogen and oxygen in a ratio of 8:2.

In addition, an outlet pipe 150 having one end connected to the test chamber 110 and the other end extending to the outside of the gas phase chamber 100 is further included.

In addition, an inlet pipe 140 having one end connected to the flow rate controller 230 and the other end connected to the test chamber 110 is further included.

Also, the flow velocity is 2 to 4 m/s.

Further, the calibration value is a coefficient added or multiplied so that the output of the NO ₂ sensor matches the concentration.

In addition, the discharge pipe 290 connected to the outlet pipe; a vacuum pump 270 installed on the discharge pipe 290; A first valve 275 installed between the discharge pipe 290 and the vacuum pump 270; A vacuum sensor 280 installed on the discharge pipe 290; A second valve 285 installed between the discharge pipe 290 and the vacuum sensor 280; And a third valve 295 installed at the end of the discharge pipe 290; may further include.

In addition, the controller 260 calculates a calibration value of the NO ₂ sensor based on the temperature, concentration, and flow rate of the temperature sensor 120 , the output of the NO ₂ sensor, and the atmospheric pressure of the vacuum sensor 280 .

Another object of the present invention is a calibration method using the calibration device described above, comprising: installing an NO ₂ sensor 130 in a test chamber 110 (S100); Setting the weather chamber 100 accommodating the test chamber 110 to a constant temperature (S120); The first valve 275 connected to the vacuum pump 270 and the second valve 285 connected to the vacuum sensor 280 are closed, and the third valve 295 installed at the end of the discharge pipe 290 is opened. , Setting the concentration of NO ₂ with the gas mixer 220, and setting the flow rate of the mixed gas with the flow rate controller 230 (S140); Injecting NO ₂ certified standard material and air into the gas mixer 220 (S160); measuring the temperature of the test chamber 110 with the temperature sensor 120 and measuring the concentration of NO2 with the NO ₂ sensor 130 (S180); and calculating, by the controller 260, a calibration value of the NO ₂ sensor based on the temperature of the temperature sensor 120, the set concentration, the flow rate, and the concentration of the NO ₂ sensor (S190). It can also be achieved by the calibration method of the NO ₂ sensor for use.

An object of the present invention, as a second embodiment of another category, is a calibration method using the calibration device described above, comprising the steps of installing the NO ₂ sensor 130 in the test chamber 110 (S200); Setting the weather chamber 100 accommodating the test chamber 110 to a constant temperature (S220); The first valve 275 connected to the vacuum pump 270 and the second valve 285 connected to the vacuum sensor 280 are opened, and the third valve 295 installed at the end of the discharge pipe 290 is closed. , setting the concentration of NO ₂ with the gas mixer 220 and opening the flow control unit 230 so that the test chamber 110 has a pressure of 1 atm of the mixed gas (S240); operating the vacuum pump 270 so that the test chamber 110 has a specific air pressure (S260); closing the first valve 275 (S270); measuring the temperature of the test chamber 110 with the temperature sensor 120 and measuring the concentration of NO ₂ with the NO ₂ sensor 130 (S280); and calculating, by the controller 260, a calibration value of the NO ₂ sensor based on the temperature of the temperature sensor 120, the set concentration, atmospheric pressure, and the concentration of the NO ₂ sensor (S290). It can also be achieved by the calibration method of the NO ₂ sensor for use.

In addition, the constant temperature is in the range of -40 ℃ ~ 40 ℃.

In addition, the set concentration is in the range of 0 to 100 ppb.

According to one embodiment of the present invention, it is possible to implement a high-level weather environment on the ground and calibrate the NO ₂ sensor in the implemented high-level weather environment. Therefore, when the radiosonde equipped with the NO ₂ sensor is installed, a very accurate NO ₂ concentration can be measured. Through this, the vertical distribution of NO ₂ concentration can be known.

In addition, accurate calibration can be made by setting the temperature, flow rate, and atmospheric pressure as environmental variables of the high-rise meteorological environment.

However, the effects obtainable in the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the technical idea of the present invention, the present invention is the details described in such drawings should not be construed as limited to
1 is a schematic block diagram of a calibration device for a NO ₂ sensor for a radiosonde according to an embodiment of the present invention;
Figure 2 is a gas flow diagram of the calibration device shown in Figure 1;
Figure 3 is a flow chart showing the steps of operating the calibration device shown in Figure 1 under atmospheric pressure conditions;
Figure 4 is a flow chart showing the steps of operating the calibration device shown in Figure 1 in a flow-free condition.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, since the description of the present invention is only an embodiment for structural or functional description, the scope of the present invention should not be construed as being limited by the embodiments described in the text. That is, since the embodiment can be changed in various ways and can have various forms, it should be understood that the scope of the present invention includes equivalents capable of realizing the technical idea. In addition, since the object or effect presented in the present invention does not mean that a specific embodiment should include all of them or only such effects, the scope of the present invention should not be construed as being limited thereto.

The meaning of terms described in the present invention should be understood as follows.

Terms such as "first" and "second" are used to distinguish one component from another, and the scope of rights should not be limited by these terms. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element. It should be understood that when an element is referred to as “connected” to another element, it may be directly connected to the other element, but other elements may exist in the middle. On the other hand, when an element is referred to as being “directly connected” to another element, it should be understood that no intervening elements exist. Meanwhile, other expressions describing the relationship between components, such as “between” and “immediately between” or “adjacent to” and “directly adjacent to” should be interpreted similarly.

Singular expressions should be understood to include plural expressions unless the context clearly dictates otherwise, and terms such as “comprise” or “having” refer to a described feature, number, step, operation, component, part, or It should be understood that it is intended to indicate that a combination exists, and does not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless defined otherwise. Terms defined in commonly used dictionaries should be interpreted as consistent with meanings in the context of related art, and cannot be interpreted as having ideal or excessively formal meanings unless explicitly defined in the present invention.

Configuration of the embodiment

Hereinafter, the configuration of a preferred embodiment will be described in detail with reference to the accompanying drawings. 1 is a schematic block diagram of a calibration device for a NO ₂ sensor for a radiosonde according to an embodiment of the present invention, and FIG. 2 is a gas flow diagram of the calibration device shown in FIG. 1 . As shown in FIGS. 1 and 2, the NO ₂ CRM (Certified Reference Material, 200) contains NO ₂ certified reference materials compressed. NO ₂ Certified Standard Material consists of NO ₂ and air in the concentration range of 50 ~ 200 ppm.

Air (air) is compressed and accommodated in the air unit 210 . Air contains nitrogen and oxygen in a ratio of 8:2.

The NO ₂ CRM 200 and the air unit 210 are connected to the input side of the gas mixer 220, and the concentration of NO ₂ is controlled by adjusting the mixing ratio of NO ₂ and air. The output side of the gas mixer 220 is connected to the flow control unit 230. The gas mixer 220 may be set to a concentration of NO ₂ in the range of 0 to 100 ppb. These concentration ranges correspond to those in the troposphere.

The input side of the mass flow controller 230 is connected to the gas mixer 230, and the output side is connected to the inlet pipe 140. The flow rate controller 230 controls the flow rate of the mixed gas mixed by the gas mixer 230 . The flow velocity is 2 to 4 m/s. This range of flow rates corresponds to the flight speed of the radiosonde.

The inlet pipe 140 connects between the flow rate controller 230 and the test chamber 110 to supply the mixed gas, and the outlet pipe 150 connects the test chamber 110 and the discharge pipe 290 to supply the mixed gas. functions to excrete.

The test chamber 110 is an enclosed space for fluid flow, and a radio sonde NO ₂ sensor is installed therein, and a temperature sensor 120 for measuring temperature is installed.

The weather chamber 100 is a constant temperature chamber in which the test chamber 110 is accommodated and temperature control (eg, -40 ° C to 40 ° C) is possible. These temperature ranges correspond to tropospheric temperature ranges.

One end of the discharge pipe 290 is connected to the outlet pipe 150, and the other end is exposed to the atmosphere. Optionally, the discharge pipe 290 and the discharge pipe 150 may be integrated. The vacuum sensor 280 is a pressure sensor installed close to the outlet pipe 150 on the outlet pipe 290. A second valve 285 that can be opened and closed is provided between the discharge pipe 290 and the vacuum sensor 280 .

A vacuum pump 270 is provided downstream of the discharge pipe 290, and a first valve 275 that can be opened and closed is provided between the vacuum pump 270 and the discharge pipe 290. The vacuum pump 270 implements a pressure in the range of 100 to 1,000 hPa.

The end of the discharge pipe 290 is exposed to the atmosphere, and a third valve 295 is provided to open and close the end.

A digital multi meter (DMM) 240 amplifies the outputs of the temperature sensor 120 and the NO2 sensor 130, converts them into digital outputs, and transmits the outputs to the interface 250.

The interface unit 250 is connected to the DMM 240, and is connected to the weather chamber 100, the flow control unit 230, and the gas mixer 220. The interface unit 250 may be an IEEE General Purpose Interface Bus (GPIB) method.

The controller 260 may be a computer connected to the interface 250 . The control unit 260 may receive the measured result from the interface unit 250, calculate a calibration value by executing a built-in program, and store and output the calculated calibration value. In particular, the controller 260 calculates a calibration value of the NO _{2 sensor based on the temperature, concentration, flow rate, air pressure of the temperature sensor 120 and the output of the NO 2 sensor} . The correction value is a coefficient that is added or multiplied so that the output of the NO ₂ sensor matches the set concentration at the corresponding temperature, flow rate, and atmospheric pressure.

Operation of Embodiment (1)

Hereinafter, the operation of the preferred embodiment will be described in detail with reference to the accompanying drawings. Figure 3 is a flow chart showing the steps of operating the calibration device shown in Figure 1 under atmospheric pressure conditions. As shown in FIG. 3, first, the NO ₂ sensor 130 is installed in the test chamber 110 (S100).

Next, the weather chamber 100 accommodating the test chamber 110 is set to a constant temperature (eg, -20° C.) (S120). At this time, a sufficient time is maintained so that the inside of the test chamber 110 becomes a uniform temperature. The temperature inside the test chamber 110 may be measured through the temperature sensor 120 .

Then, the first and second valves 275 and 285 are closed, and the third valve 295 is opened. Thus, the discharge pipe 290 communicates with the atmosphere without the influence of the vacuum pump 270 or the vacuum sensor 280.

Then, the concentration of NO ₂ (eg, one of 10 ppb, 30 ppb, 50 ppb, and 70 ppb) is set by the gas mixer 220, and the flow rate of the mixed gas (eg, 2 m/s) is set by the flow rate controller 230. , 3 m/s or 4 m/s) is set (S140). The setting of the gas mixer 220 and the flow control unit 230 may be performed according to a command of the control unit 260 through the interface unit 250.

Then, NO ₂ certified standard material and air are introduced into the gas mixer 220 (S160).

Then, the temperature of the test chamber 110 is measured by the temperature sensor 120, and the concentration of NO ₂ is measured by the NO ₂ sensor 130 (S180). The measured temperature and concentration are transmitted to the control unit 260 through the DMM 240 and the interface unit 250.

Next, the controller 260 calculates a calibration value of the NO ₂ sensor based on the received temperature of the temperature sensor 120 , the set concentration, the flow rate, and the measured concentration of the NO ₂ sensor (S190). The calibration value is a coefficient (eg 1.324) that is added or multiplied so that the output of the NO ₂ sensor at the corresponding temperature and flow rate matches the set concentration.

Operation (2) of the embodiment

Figure 4 is a flow chart showing the steps of operating the calibration device shown in Figure 1 in a flow-free condition. As shown in FIG. 4 , first, the NO ₂ sensor 130 is installed in the test chamber 110 (S200).

Next, the weather chamber 100 is set to a constant temperature (S220).

Then, the first valve 275 connected to the vacuum pump 270 and the second valve 285 connected to the vacuum sensor 280 are opened, and the third valve 295 installed at the end of the discharge pipe 290 close Thus, the test chamber 110, the outlet pipe 150, and the discharge pipe 290 form an airtight space without flow velocity, and the pressure is varied only by the operation of the vacuum pump 270.

Then, the concentration of NO ₂ is set by the gas mixer 220, and the flow control unit 230 is opened so that the test chamber 110 has a pressure of 1 atm of the mixed gas (S240).

Next, the vacuum pump 270 is operated so that the test chamber 110 has a specific atmospheric pressure (S260). At this time, the specific air pressure is a low pressure selected from the range of 100 to 1,000 hPa.

Then, the first valve 275 is closed to block the vacuum pump 270 and the discharge pipe 290 (S270).

Then, the temperature of the test chamber 110 is measured by the temperature sensor 120, and the concentration of NO ₂ is measured by the NO ₂ sensor 130 (S280).

Next, the controller 260 calculates a calibration value of the NO ₂ sensor based on the temperature of the temperature sensor 120, the set concentration, a specific atmospheric pressure, and the measured concentration of the NO ₂ sensor (S290). The calibration value is a coefficient (eg 1.324) that is added or multiplied so that the output of the NO ₂ sensor matches the set concentration at the corresponding temperature, set concentration and specific barometric pressure.

Detailed descriptions of the preferred embodiments of the present invention disclosed as described above are provided to enable those skilled in the art to implement and practice the present invention. Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the scope of the present invention. For example, those skilled in the art can use each configuration described in the above-described embodiments in a manner of combining with each other. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The present invention may be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention. Accordingly, the above detailed description should not be construed as limiting in all respects and should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention. The invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, claims that do not have an explicit citation relationship in the claims may be combined to form an embodiment or may be included as new claims by amendment after filing.

100: weather chamber,
110: test chamber,
120: temperature sensor,
130: NO ₂ sensor,
140: inlet pipe,
150: outflow pipe,
200: NO ₂ CRM (certified reference material),
210: air unit,
220: gas mixer,
230: flow rate control unit,
240: DMM (Digital Multi Meter),
250: interface unit,
260: control unit,
270: vacuum pump,
275: first valve,
280: vacuum sensor,
285: second valve,
290: discharge pipe,
295: third valve.

Claims (12)

NO ₂ CRM (200) accommodating NO ₂ certified reference materials;
an air unit 210 in which air is accommodated;
a gas mixer 220 connected to the NO ₂ CRM 200 and the air unit 210 and controlling a concentration of NO ₂ by adjusting a mixing ratio of NO ₂ and air;
A flow rate control unit 230 connected to the gas mixer 220 to control the flow rate of gas;
a test chamber 110 in which an NO ₂ sensor for a radiosonde is installed and supplied with the gas from the flow rate controller 230;
a weather chamber 100 in which the test chamber 110 is accommodated and capable of temperature control;
a temperature sensor 120 for measuring the temperature of the test chamber 110; and
a controller 260 calculating a calibration value of the NO _{2 sensor based on the temperature, the concentration, the flow rate, and the output of the NO 2 sensor} of the temperature sensor 120;
an outlet pipe 150 having one end connected to the test chamber 110 and the other end extending to the outside of the gas phase chamber 100;
a discharge pipe 290 connected to the outlet pipe;
a vacuum pump 270 installed on the discharge pipe 290;
a first valve 275 installed between the discharge pipe 290 and the vacuum pump 270;
a vacuum sensor 280 installed on the discharge pipe 290;
a second valve 285 installed between the discharge pipe 290 and the vacuum sensor 280; and
A third valve 295 installed at an end of the discharge pipe 290; Calibration device for NO ₂ sensor for a radio sonde, characterized in that it comprises a. delete According to claim 1,
The NO ₂ sensor calibration device for a radiosonde, characterized in that it further comprises an inlet pipe 140 having one end connected to the flow rate controller 230 and the other end connected to the test chamber 110. According to claim 1,
The flow rate is 2 ~ 4 m / s, characterized in that for radio sonde NO ₂ Calibration device of the sensor. According to claim 1,
The calibration value is a coefficient added or multiplied so that the output of the NO ₂ sensor matches _the concentration. delete According to claim 1,
The controller 260 calculates a calibration value of the NO ₂ sensor based on the temperature of the temperature sensor 120, the concentration, the flow rate, the output of the NO ₂ sensor, and the atmospheric pressure of the vacuum sensor 280. A calibration device for a NO ₂ sensor for a radiosonde. In the calibration method using the calibration device according to any one of claims 1, 3 to 5 and 7,
installing the NO ₂ sensor 130 in the test chamber 110 (S100);
Setting the weather chamber 100 accommodating the test chamber 110 to a constant temperature (S120);
The first valve 275 connected to the vacuum pump 270 and the second valve 285 connected to the vacuum sensor 280 are closed, and the third valve 295 installed at the end of the discharge pipe 290 is opened. , Setting the concentration of NO ₂ with the gas mixer 220, and setting the flow rate of the mixed gas with the flow rate controller 230 (S140);
Injecting NO ₂ certified standard material and air into the gas mixer 220 (S160);
measuring the temperature of the test chamber 110 with the temperature sensor 120 and measuring the concentration of NO ₂ with the NO ₂ sensor 130 (S180); and
Calculating, by the controller 260, a calibration value of the NO ₂ sensor based on the temperature of the temperature sensor 120, the set concentration, the flow rate, and the concentration of the NO ₂ sensor (S190); Calibration method of NO ₂ sensor for radiosonde. In the calibration method using the calibration device according to any one of claims 1, 3 to 5 and 7,
installing the NO ₂ sensor 130 in the test chamber 110 (S200);
Setting the weather chamber 100 accommodating the test chamber 110 to a constant temperature (S220);
The first valve 275 connected to the vacuum pump 270 and the second valve 285 connected to the vacuum sensor 280 are opened, and the third valve 295 installed at the end of the discharge pipe 290 is closed. , setting the concentration of NO ₂ with the gas mixer 220 and opening the flow control unit 230 so that the test chamber 110 has a pressure of 1 atm of the mixed gas (S240);
operating the vacuum pump 270 so that the test chamber 110 has a specific atmospheric pressure (S260);
closing the first valve 275 (S270);
measuring the temperature of the test chamber 110 with the temperature sensor 120 and measuring the concentration of NO ₂ with the NO ₂ sensor 130 (S280); and
Calculating _{, by the controller 260, a calibration value of the NO 2 sensor based on the temperature of the temperature sensor 120, the set concentration, the air pressure, and the concentration of the NO 2 sensor} (S290); Calibration method of NO ₂ sensor for radiosonde. According to claim 8,
The constant temperature is -40 ° C to 40 ° C. Calibration method of the NO ₂ sensor for radiosonde, characterized in that the range. According to claim 8,
The set concentration is a method for calibrating a NO ₂ sensor for a radiosonde, characterized in that in the range of 0 to 100 ppb. According to claim 8,
The flow velocity is 2 ~ 4 m / s, characterized in that the calibration method of the NO ₂ sensor for radio sonde.

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