JP2009145146A - Environment measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily measure an atmospheric environment in a short time. <P>SOLUTION: This device is equipped with an oxidation part 12 for adding gas oxidizing a metal as an oxidizing agent to the atmosphere collected from the atmospheric environment, a measuring element 15 having a metal part, a discharge tube 14 for discharging gas including the atmosphere and the added oxidizing agent to the metal part 15, and a measuring part 18 for measuring the atmospheric environment by measuring a corrosion state of the metal part 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an environment measuring device for measuring an atmospheric environment.

Devices such as electronic equipment and electrical equipment are sulfur dioxide gas (SO ₂ ), hydrogen sulfide gas (H ₂ S), nitrogen dioxide gas (NO ₂ ), chlorine gas (Cl ₂ ), etc. contained in the installed atmospheric environment. When affected by corrosive gases such as Therefore, measuring the atmospheric environment in which the equipment is installed and evaluating the atmospheric environment is important for equipment manufacturers and equipment users.

  On the other hand, the corrosive gas concentration in the atmospheric environment where the equipment is installed is generally as low as 1 ppm or less, and cannot be easily measured using a commonly used gas detector or the like. Therefore, the conventional measurement of corrosive gas concentration is based on the “method of collecting the target atmosphere and scientifically analyzing the gas” or the “substance change by exposing a specific substance to the target atmosphere for a certain period of time”. Is used.

  In the conventional “method of collecting the target air”, the air collected in the environment where the equipment is installed is taken back to the laboratory and the corrosive gas contained in the atmosphere is analyzed in the laboratory. . Moreover, since gas analysis is professional, it is performed by experts. Therefore, there is a problem that the measurement result of the atmospheric environment cannot be obtained easily and in a short time at the installation location of the device.

  In addition, in the “method of exposing a specific substance to the atmosphere”, a filter sheet that has been impregnated with a metal plate or a gas adsorbing agent in the atmospheric environment where the equipment is installed is exposed for a certain period of time. Or the amount of gas adsorbed to the drug is examined. However, a period of several weeks to several months is required until a change in the weight of the metal or a change in adsorption to the drug occurs. Also in this method, the metal or filter paper exposed to the air to be measured is brought back to the laboratory or the like, and specialists obtain measurement results. Therefore, there is a problem that the measurement result cannot be obtained easily and in a short time at the installation location of the device.

On the other hand, in recent years, there is also a technique for evaluating the environment by obtaining a change in weight of a substance deposited on a crystal resonator from a change in frequency (for example, see Patent Document 1). There is also a technique in which two or more types of metal thin films are formed on a single insulating substrate, and the environment is evaluated from the amount of change in transmitted light, reflected light, and electrical resistance (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 2001-99777 Japanese Patent Laid-Open No. 2003-294606

  In the method using a crystal resonator and the method using an insulating substrate described in Patent Documents 1 and 2, a long time of several weeks to several months is not required as required by a conventional measurement method. . The methods described in the cited references 1 and 2 do not require a period as long as necessary in the past, but the metal deposited on the crystal resonator or the insulating substrate cannot be changed in a short time, and the atmospheric environment The measurement result cannot be obtained in a short time (for example, 2 to 3 hours). In addition, there is a problem that the cost is high due to the selection of a plurality of types of metals for forming a thin film and the manufacturing of a device having a complicated configuration. Further, when a crystal resonator is used, the configuration becomes complicated, and there is a problem that the cost cannot be reduced.

  In view of the above problems, the present invention provides an environment measuring apparatus that can easily measure the atmospheric environment in a short time.

  An environment measuring device according to a feature of the present invention is an environment measuring device that measures the content of corrosive gas contained in an ambient air environment, and gas that oxidizes a metal as an oxidant to the air collected from the air environment Measuring a corrosive state of the metal part, a measuring element having a metal part, a measuring element having a metal part, a discharge tube for releasing a gas containing the atmosphere and the added oxidant to the metal part, and A measurement unit for measuring the atmospheric environment.

  An environment measuring device according to another aspect of the present invention is an environment measuring device that measures the content of corrosive gas contained in the surrounding air environment, and is a humidifier that applies humidity to the air collected from the air environment. , A measuring element having a metal part, a discharge pipe for releasing a gas with humidity in the atmosphere to the metal part, and a measuring part for measuring the atmospheric environment by measuring the corrosion state of the metal part And.

  According to the present invention, the atmospheric environment can be easily measured in a short time.

  The environment measuring apparatus according to the best embodiment of the present invention is installed in the vicinity of a device such as an electronic device or an electric device whose characteristics change and its function is deteriorated when affected by corrosive gas contained in the atmosphere, Measure the gas content (presence / absence and content) that affects the equipment.

  As shown in FIG. 1, the environment measuring apparatus 1 according to the best embodiment of the present invention includes an oxidation unit 12 that introduces an oxidant into the atmosphere introduced from the introduction pipe 11, and a humidification unit 13 that gives humidity to the atmosphere. The discharge tube 14 that discharges the atmosphere supplied or humidified with the oxidant to the measurement element 15 in the chamber 16 and the measurement unit 18 that measures the state change of the measurement element 15 to determine the amount of gas contained in the atmosphere. And.

  One end of the introduction pipe 11 is present in the atmosphere for measuring the environment, and the other end is present in the environment measurement apparatus 1. In the environment measuring apparatus 1, the air to be measured is introduced from the introduction pipe 11.

The oxidation unit 12 holds a gas that becomes a metal oxidant in advance, and introduces an appropriate amount of gas (oxidant) into the atmosphere collected through the introduction pipe 11. Here, the oxidizing agent is determined by the material of the measuring element 15. For example, hydrogen peroxide gas (H ₂ O ₂ ) and ozone gas (O ₃ ) accelerate the corrosion reaction of various metals and can be collected and held at low cost. Preferred gas for the agent.

  As shown in an example in FIG. 2, the humidifying unit 13 is provided with a passage pipe 13 b through which gas can pass in a water tank 13 a in which water is stored, and when a gas with low humidity is introduced from the introduction pipe 11, Humidity is given to the passing gas, and the gas is discharged from the discharge pipe 14 as a high humidity gas. FIG. 2A is a side view of the humidifying unit 13, and FIG. 2B is a top view of the water tank 13 a of the humidifying unit 13.

  Specifically, constant temperature water is stored in the water tank 13a, and as shown in FIG. 2, a plurality of passage tubes 13b made of silicon tubes are arranged inside the water tank 13a. The gas introduced into the humidifying unit 13 is divided and introduced from the inlet 13c into the passage tube 13b. Since silicon is a substance having a large gas permeability, when the gas passes through the passage tube 13b, a part of the water stored in the water tank 13a penetrates the side surface of the passage tube 13b. Therefore, humidity is given to the gas passing through the passage tube 13b. In addition, the humidifying unit 13 supplies the discharge pipe 14 with the humidified gas discharged from the outlet 13d of the passage pipe 13b.

  At this time, in order to supply the water vapor to the gas in a short time, a method for raising the temperature of the water stored in the water tank 13a, or a large number of micro silicon having a small diameter to increase the contact area between the silicon and the gas. A method using a tube as the passage tube 13b is conceivable. Moreover, the amount of water vapor supplied to the gas can be kept constant by adjusting the water temperature of the water stored in the water tank 13a and the properties (diameter and components) of the silicon tube. The passage tube 13b can be made of a transparent polyurethane resin tube in addition to a silicon tube.

  The discharge pipe 14 discharges the gas supplied from the humidifying unit 13 and blows the gas to the measuring element 15.

  The measuring element 15 is placed at a position where the gas discharged from the discharge pipe 14 in the chamber 16 held at a constant atmospheric pressure hits. For example, when a certain amount of gas is discharged from the chamber 16 by the pump 17, the gas released from the discharge pipe 14 at a predetermined speed is blown to the measuring element 15.

  As shown in FIG. 3, the measurement element 15 has a configuration in which a metal 15c is coated on a surface 15b of a substrate 15a such as a glass substrate. Here, FIG. 3A is a top view of the measuring element 15, and FIG. 3B is a side view of the measuring element 15.

  The metal 15c coated on the measuring element 15 is determined by the type of gas to be measured. Copper (Cu) is a metal having a relatively low cost and high reactivity with general corrosive gases such as sulfur dioxide gas, hydrogen sulfide gas, nitrogen dioxide gas, chlorine gas, and ammonia gas. Therefore, it is preferable to coat the substrate 15a with copper. Hereinafter, a case where copper is coated will be described as an example.

  Corrosion by measuring sulfur dioxide gas, hydrogen sulfide gas, nitrogen dioxide gas, chlorine gas, and ammonia gas as described above in "IT-1004 Industrial Information Processing and Control Equipment Installation Environmental Standard" of "Electronic Information Technology Industry Association" Assume sex level. In addition to copper, nickel (Ni), silver (Ag), tin (Sn), zinc (Zn), aluminum (Ai), and the like can also be used as a coating metal.

  Here, the measurement time by the environment measuring apparatus 1 depends on the shape and film thickness of the metal 15c coated on the measuring element 15, in addition to the presence or absence of an oxidizing agent and humidity. The measurement time also depends on the flow rate (gas amount) when the gas is released to the measurement element 15.

  First, the shape of the metal 15c coating that affects the measurement time will be described. For example, as shown in FIG. 3A, the measuring element 15 is formed by coating a metal 15c on the surface 15b of the substrate 15a to form a reaction spot 15d in a portion having a narrow width (area). By intensively applying the released gas to the reaction spot 15d, the corrosion rate of the metal 15c can be accelerated and the measurement result can be obtained in a short time. That is, when the range of the metal 15c from which the gas is discharged from the discharge pipe 14 is wide, the gas contact method becomes non-uniform and it takes time until the metal 15c corrodes. On the other hand, if a gas is intensively applied to the reaction spot 15d in a narrow range, the gas contact is uniform and the metal 15c corrodes in a short time. It should be noted that the width and length of the reaction spot 15d through which gas is blown from the discharge pipe 14 and the shape of the coating are not limited and may not be H-shaped as shown in FIG.

  Next, the film thickness of the metal 15c coating that affects the measurement time will be described. If the thickness of the metal 15c of the measuring element 15 is thin, the metal is oxidized by a gas other than the gas to be measured, and if it is thick, it takes a long time to oxidize. In FIG. 4, the horizontal axis is the film thickness (μm), and the vertical axis is the time (minutes) elapsed from the start of measurement until the change in the electrical resistance of the copper film having a film thickness of 0.1 to 0.5 μm reaches 400 mΩ. It is a graph showing elapsed time. In addition, the measurement result shown in FIG. 4 is an example when the atmosphere contains 0.1 ppm of nitrogen dioxide gas, 0.3 ppm of hydrogen peroxide gas is added as an oxidizing agent, and the humidity is 80%.

  In the example shown in FIG. 4, until the amount of change in electrical resistance from the start of measurement reaches 400Ω, for example, it is within 240 minutes (4 hours) when the film thickness is 0.3 μm, but the film thickness is 0 It takes about 360 minutes (6 hours) when .4 μm and it takes about 480 minutes (8 hours) when the film thickness is 0.5 μm. That is, when the film thickness is thick, the rate at which the corrosion proceeds is slow, so that it takes time to change the electrical resistance.

  FIG. 5 is a graph showing the electrical resistance of copper having a thickness of 0.02 to 0.1 μm, with the horizontal axis representing the film thickness (μm) and the vertical axis representing the electrical resistance (Ω). In the example shown in FIG. 5, the electrical resistance tends to increase as the film thickness decreases. This is because when the film thickness is reduced, it becomes difficult to uniformly coat the metal on the surface of the substrate, and a portion where the metal becomes discontinuous is generated on the surface of the substrate, resulting in an increase in electrical resistance.

  As shown in FIGS. 4 and 5, it is difficult to accurately determine the amount of change in electrical resistance in a short time even if the film thickness of the metal 15 c of the measuring element 15 is too thick or too thin. From the graphs shown in FIG. 4 and FIG. 5, it is optimal that the film thickness is about 0.05 to 0.3 μm. In the following, the measurement element 15 coated with copper having a film thickness of 0.1 μm is taken as an example. explain.

  Next, the gas flow rate (gas release amount) that affects the measurement time will be described. For example, if the flow rate of the gas released from the discharge pipe 14 is small, the corrosion reaction rate of copper coated on the measuring element 15 becomes small, and if the flow rate is too large, the corrosion reaction rate of copper becomes small. FIG. 6 is a graph showing changes in electrical resistance (mΩ) on the horizontal axis, gas flow rate (ml / min) on the vertical axis, and 0.1 μm of 0.1 μm when 0.3 ppm of hydrogen peroxide gas is added as an oxidizing agent. It shows the amount of change in electrical resistance before and after 4 hours from the start of measurement of copper coated with a film thickness. According to FIG. 6, it can be seen that when the flow rate of the gas discharged from the discharge pipe 14 exceeds 1000 ml / min, the amount of change in electrical resistance is small, and when the flow rate is too large, the corrosion rate is small. Therefore, it is desirable that the pump 17 controls the flow rate of the gas discharged from the discharge pipe 14 so as to minimize the copper corrosion reaction rate. When the conditions are the same as those in FIG. It can be seen that 1000 ml / min is appropriate and the corrosion reaction rate can be adjusted to the shortest.

  The measurement unit 18 measures the amount of gas based on the amount of change in electrical resistance of the measurement element 15. For example, the measuring unit 18 is a resistance measuring instrument, and measures the electric resistance of the metal 15c coated on the measuring element 15. The content of corrosive gas contained in the atmospheric environment can be measured by the amount of change in the electrical resistance of the metal 15c measured by the measuring unit 18. That is, when the corrosive gas is contained in the atmospheric environment, the electric resistance changes in a short time, and when the corrosive gas is contained in a large amount in the atmospheric environment, the change time of the electric resistance is further shortened. Therefore, it is difficult to obtain detailed data such as the content of corrosive gas in the atmospheric environment and the type of corrosive gas contained. Large and small) can be measured.

  The environment measuring device 1 includes the oxidation unit 12 and the humidification unit 13 and adds the oxidant to the gas and the vapor, but may have only one of the oxidation unit 12 and the humidification unit 13. . It should be noted that the corrosion reaction is accelerated when the humidity is higher than the low one, and the oxidizing agent is more likely to react with the metal coated on the surface 15b of the substrate. Therefore, in order to perform environmental measurement in a shorter time, It is clear from the measurement result of FIG. 7 that it is preferable to provide both the oxidation unit 12 and the humidification unit 13.

  FIG. 7 shows an environment measuring apparatus 1 having a measuring element 15 coated with copper with a thickness of 0.1 μm in an atmospheric environment containing sulfur dioxide gas, hydrogen sulfide gas, nitrogen dioxide gas or chlorine gas as a corrosive gas. The change in the electrical resistance of copper before the start of measurement and the change in the electrical resistance of copper after 4 hours from the start of measurement is 200 mΩ or more or 200 mΩ or less. In addition, the example of FIG. 7 adds 0.6 ppm ozone as an oxidizing agent, 0.1 ppm sulfur dioxide gas, 0.01 ppm hydrogen sulfide gas, 0.05 ppm nitrogen dioxide gas as corrosive gas in the atmosphere. This is an example in which 0.01 ppm of chlorine gas is contained.

  According to FIG. 7, for example, when the humidity is 40% and no oxidizing agent is added, the amount of change in electrical resistance before the start of measurement and after 4 hours from the start of measurement is 200 mΩ or less. On the other hand, when the humidity is 40% and an oxidizing agent is added, the amount of change in electrical resistance before the start of measurement and after 4 hours from the start of measurement differs depending on the corrosive gas contained in the atmospheric environment. That is, when the corrosive gas is hydrogen sulfide gas, a change in electric resistance of 200 mΩ or more is generated, but in the case of sulfur dioxide gas, nitrogen dioxide gas and chlorine gas, the change in electric resistance of 200 mΩ or more is It has not occurred.

  When the humidity is 80% and no oxidant is added, the amount of change in electrical resistance before the start of measurement and after 4 hours from the start of measurement is 200 mΩ or less. On the other hand, when the humidity is 80% and an oxidizing agent is added, the amount of change in electrical resistance before the start of measurement and after 4 hours from the start of measurement is 200 mΩ or more.

  In addition, although description using illustration is abbreviate | omitted, when the humidity is 60% or less, the experiment has obtained the result that the corrosion rate of a metal is small and long measurement time is required.

  FIG. 8 shows the measurement time (minutes) on the horizontal axis and the amount of change in electrical resistance (mΩ) on the vertical axis when the hydrogen sulfide gas concentration is 0.1 ppm, 0.05 ppm, and 0.01 ppm, respectively, in the environment measurement apparatus 1. Represents the amount of change in the electrical resistance of copper coated on the measuring element 15 from 240 minutes (4 hours) after the start of measurement. FIG. 8 shows an example in which the oxidation portion 12 uses 0.6 ppm hydrogen peroxide gas as an oxidant, and the humidification portion 13 measures the amount of change in electrical resistance in a state where the humidity of the gas is humidified to 80%. From the result shown in FIG. 8, it can be seen that a change in electrical resistance appears in about 120 minutes (2 hours).

  Further, in FIG. 9, the horizontal axis represents the measurement time (minutes) and the vertical axis represents the change in electrical resistance (mΩ), and the chlorine gas concentrations in the environmental measurement apparatus 1 are 0.1 ppm, 0.05 ppm, and 0.02 ppm, respectively. This represents the amount of change in the electrical resistance of copper coated on the measuring element 15 from the start of the measurement to 240 minutes (4 hours) later. FIG. 9 shows an example in which the oxidation portion 12 uses 0.6 ppm hydrogen peroxide gas as an oxidant, and the humidification portion 13 measures the change in electrical resistance in a state where the humidity of the gas is humidified to 80%. From the results shown in FIG. 9, it can be seen that a change in electrical resistance appears in about 120 minutes (2 hours).

  According to FIG. 8 and FIG. 9 described above, if an oxidizing agent, water vapor (humidity) or the like is effectively used, the metal is corroded by the corrosive gas contained in the environmental atmosphere even in a short time of about 2 hours, and the electric resistance is obtained. It can be seen that the influence of the corrosive gas can be measured.

  As described above, according to the environment measuring apparatus according to the best embodiment of the present invention, the oxidizing agent or the vapor is added to the air to be measured to promote the corrosion of the metal of the measuring element. Therefore, the measurement result can be obtained in a short time of about 4 hours as compared with the conventional measurement method.

  That is, it is common for equipment to perform regular maintenance and the like, but this maintenance takes about 4 hours. Therefore, if the environment measuring apparatus 1 described above is used, it is possible to measure the atmospheric environment around the device within the maintenance time. By making a detailed measurement only when necessary after it becomes clear that corrosive gas is contained in the atmospheric environment by simple measurement using the environmental measurement device described above using maintenance time, It is sufficient to perform large-scale measurement with a long measurement time in all atmospheric environments as in the past, and the labor of measurement can be reduced.

<Modification>
The discharge tube 14 can also be provided with a partition wall 14a as shown in FIG. When the partition wall 14a is provided in the discharge tube 14, gas turbulence is prevented, and in the measuring element 15, the gas discharged from the discharge tube 14 uniformly hits the surface 15b of the substrate. Therefore, the surface 15b of the substrate 15a is corroded. The reaction can be made uniform. At this time, in order to minimize the pressure loss of the gas to be released, it is desirable to use a thin plate for the partition wall.

It is a figure showing the environment measurement apparatus which concerns on best embodiment of this invention. It is a figure explaining the humidification part of the environment measuring apparatus of FIG. It is a figure explaining the measuring element of the environment measuring apparatus of FIG. It is a graph showing time until it produces the variation | change_quantity of a film thickness and a predetermined electrical resistance. It is a graph showing the relationship between a film thickness and an electrical resistance. It is a graph showing the relationship between a flow velocity and electrical resistance. It is a figure explaining the influence on the variation | change_quantity of the electrical resistance by an oxidizing agent and humidity. It is an example which measured the influence by hydrogen sulfide gas. It is an example which measured the influence by chlorine gas. It is a figure explaining the discharge tube of the environment measuring device concerning a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Environmental measuring apparatus 11 ... Introducing pipe 12 ... Oxidizing part 13 ... Humidifying part 13a ... Water tank 13b ... Passing pipe 13c ... Inlet 13d ... Outlet 14 ... Release pipe 14a ... Septum 15 ... Measuring element 15a ... Substrate 15b ... Surface 15c ... Metal (Metal part)
15d ... Reaction spot 16 ... Chamber 17 ... Pump 18 ... Measuring unit

Claims (9)

An environmental measuring device for measuring the content of corrosive gas contained in the surrounding atmospheric environment,
An oxidation part for adding a gas that oxidizes a metal as an oxidant to the atmosphere collected from the atmospheric environment;
A measuring element having a metal part;
A discharge pipe that discharges, to the metal part, a gas in which the oxidizing agent is added to the atmosphere in the oxidation part;
A measurement unit for measuring the atmospheric environment by measuring the corrosion state of the metal part;
An environment measuring device comprising: An environmental measuring device for measuring the content of corrosive gas contained in the surrounding atmospheric environment,
A humidifying unit for applying humidity to the atmosphere collected from the atmospheric environment;
A measuring element having a metal part;
A discharge pipe for releasing a gas in which humidity is given to the atmosphere in the humidifying section to the metal part;
A measurement unit for measuring the atmospheric environment by measuring the corrosion state of the metal part;
An environment measuring device comprising: Further comprising a humidifying unit for applying humidity to the collected atmosphere,
The environment measuring device according to claim 1, wherein the discharge pipe releases the gas to which the oxidizer is added in the oxidation portion and humidity is given in the humidification portion to the metal portion. The metal part is a thin film in which the surface of the measuring element is coated with a single metal or alloy having a high reaction with at least one of sulfurous acid gas, hydrogen sulfide gas, nitrogen oxide gas, chlorine gas, and ammonia gas And
The environmental measurement according to any one of claims 1 to 3, wherein the measurement unit measures the amount of change in electrical resistance of the metal part to measure the state of corrosive gas contained in the atmospheric environment. apparatus. The metal part is a thin film coated with copper on the surface of the measuring element,
The environmental measurement according to any one of claims 1 to 3, wherein the measurement unit measures the amount of change in electrical resistance of the metal portion to measure the state of corrosive gas in the atmospheric environment. apparatus.   6. The environment measuring apparatus according to claim 4, wherein the thin film has a thickness of 0.05 to 0.3 [mu] m. The humidifying part is
A water tank filled with water;
A passage tube disposed in the water tank, through which the gas can pass and water in the water tank is transmitted as water vapor, and gives humidity to the passing gas;
The environment measuring device according to claim 2, wherein the environmental measuring device is provided. The measuring element is installed in a chamber at a constant pressure,
8. The pump according to claim 1, further comprising a pump that controls an atmospheric pressure in the chamber so that the gas is discharged from the discharge pipe to the metal portion at a flow rate of 400 to 1000 ml / min. Environmental measuring device.   9. The discharge pipe according to claim 1, wherein the discharge pipe controls the direction of the gas to be released by providing a partition in a direction parallel to the wall surface of the discharge pipe at a discharge port for discharging the gas. Environmental measuring device.

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