JP5664444B2 - Quartz microbalance corrosion sensor, corrosion sensor system, and corrosion gas measurement method - Google Patents

Description

  The present invention relates to a quartz microbalance corrosion sensor, a corrosion sensor system, and a corrosion gas measurement method, for example, a quartz crystal microbalance corrosion sensor, a corrosion sensor system, and a corrosion gas measurement method capable of continuous measurement for a long time.

  It is well known that corrosive gases such as hydrogen sulfide are contained in the air in the living environment, and such corrosive gases have an adverse effect such as promoting the deterioration of electronic devices even at low concentrations. ing. For this reason, it is necessary to always monitor the influence of the corrosive gas contained in the atmosphere in the installation environment of the electronic device.

  Conventionally, a quartz microbalance (QCM) corrosion sensor is used for monitoring the corrosive gas in the living environment.

  The structure of this QCM corrosion sensor is the same as that of a normal QCM sensor, but uses a metal that corrodes with the corrosive gas of interest as an electrode material, and a quartz disk (AT cut) is sandwiched between two sensor electrodes. Structure.

  When this QCM corrosion sensor is installed in a corrosive gas, the surface of the sensor electrode corrodes, and the sensor resonance frequency decreases corresponding to the thickness of the corroded film thickness. By monitoring the amount of decrease (rate) over time, the degree of corrosion of the environment where the QCM corrosion sensor is installed can be recognized in real time.

  In general, in the measurement of the corrosive environment, the environment is monitored by measuring the corrosive amount during a short period of time, usually for a week, usually for several consecutive months. Sources of corrosive gas are mainly paper mills, rubber factories, waste disposal plants, etc., but there are also cases where things around the living environment are sources.

  Depending on the conditions of these sources, a lot of corrosive gas may be released in the vicinity, and the corrosive gas concentration changes greatly in a short time. For this reason, in order to monitor corrosive gas, it is important not only to measure for a long time but also to perform continuous measurement.

JP 2003-222581 A Japanese Patent Laid-Open No. 07-113740

  However, as described above, in the QCM corrosion sensor, the sensor electrode itself becomes a corrosion reaction site. Therefore, if the exposure is continued in a corrosive environment, the corrosion proceeds and the electrodes are damaged, and the QCM corrosion sensor eventually becomes inoperable.

  FIG. 13 is an explanatory diagram of the operating characteristics of the QCM corrosion sensor. As shown in FIG. 13A, the corrosion progresses with time and the frequency change gradually increases (decreases in frequency). Falls into measurement impossible. FIG. 13B is a conceptual configuration diagram of the QCM corrosion sensor in the initial stage of measurement, and FIG. 13C is a conceptual configuration diagram of the QCM corrosion sensor that has become impossible to measure. As shown in FIG. 13C, severe corrosion is observed on the surface of the sensor electrode.

  The time (life) that the QCM corrosion sensor can be used depends on the type of corrosive gas and the concentration of corrosive gas, but if only one sensor is used, measurement will be performed when this sensor becomes inoperable. Will end.

  Long-term measurement of the corrosive gas in the environmental atmosphere is possible by replacing the QCM corrosion sensor one after another whenever the QCM corrosion sensor becomes unusable. As described above, continuous monitoring is also important for monitoring corrosive gases in the environment. In other words, it is important how to shorten the time from when the sensor becomes disabled to when the sensor is replaced with a new one and sensing is started again.

  However, it is not realistic for a person to constantly monitor the operation of the sensor during the measurement period. In addition, the concentration of the corrosive gas in the environment varies greatly depending on the measurement location, and also varies greatly depending on the time. Therefore, it is difficult to predict the sensor status and set the replacement time in advance. For these reasons, it has been difficult to continuously measure and monitor the corrosive gas for a long time with the QCM corrosion sensor.

  Accordingly, an object of the present invention is to continuously measure and monitor a corrosive gas for a long time.

From one aspect disclosed, a quartz crystal microbalance corrosion comprising: a quartz disk; sensor electrodes provided on the front and back sides of the quartz disk; and a deterioration measuring conductive member provided on the front and back sides of the quartz disk. A sensor is provided.

Further, from another point of view, a plurality of the above-described quartz microbalance corrosion sensors are housed in a casing through a partition wall, and the quartz crystal microbalance corrosion sensor for measurement is exposed to the measurement atmosphere and is on standby. An opening / closing mechanism comprising a shutter member for isolating the quartz microbalance corrosion sensor for measurement or the quartz microbalance corrosion sensor for which measurement has been completed from a measurement atmosphere, and opening and closing the shutter member by a measurement signal from the conductive member for deterioration measurement A corrosion sensor system comprising: a switching mechanism for switching from the quartz microbalance corrosion sensor for measurement to the quartz microbalance corrosion sensor for standby according to opening and closing of the shutter member Is done.

Further, from another viewpoint to be disclosed, it is characterized by comprising a crystal disk, sensor electrodes provided on the front and back of the crystal disk, and a deterioration measuring conductive member provided on the front and back of the crystal disk. There is provided a method for measuring a corrosive gas, wherein the corrosion state is monitored by an output from the deterioration measuring conductive member of the quartz microbalance corrosion sensor.

According to another aspect of the disclosure, a quartz crystal microbalance corrosion sensor comprising a quartz disk, sensor electrodes provided on the front and back sides of the quartz disk, and a conductive member for deterioration measurement provided on the front and back sides of the quartz disk. Are placed in a housing with a partition wall, and the output from the conductive member for deterioration measurement of the quartz microbalance corrosion sensor being measured is compared with a predetermined sensor replacement index resistance value to stand by. There is provided a method for measuring a corrosive gas, characterized by switching to the quartz crystal microbalance corrosion sensor.

  According to the disclosed quartz microbalance corrosion sensor, corrosion sensor system, and corrosion gas measurement method, it becomes possible to continuously measure and monitor the corrosion gas for a long time.

It is a schematic block diagram of the QCM corrosion sensor of embodiment of this invention. It is explanatory drawing of the sensor replacement time of the QCM corrosion sensor of embodiment of this invention. It is an example of a time-dependent change of the resonant frequency. It is composition explanatory drawing of the QCM corrosion sensor element of Example 1 of this invention. It is an apparatus block diagram of the QCM corrosion sensor of Example 1 of this invention. It is a conceptual system block diagram of the corrosion sensor system of Example 2 of this invention. It is explanatory drawing of the open / close state of a sensor cell part. It is explanatory drawing of the correlation of switching of a QCM corrosion sensor element, frequency change, resistance change, and step motor current. It is explanatory drawing of operation | movement of the corrosion sensor system of Example 3 of this invention. It is explanatory drawing of the corrosion state to which Example 4 of this invention is applied. It is explanatory drawing of operation | movement to the middle of the corrosion sensor system of Example 4 of this invention. It is explanatory drawing of operation | movement after FIG. 11 of the corrosion sensor system of Example 4 of this invention. It is explanatory drawing of the operating characteristic of a QCM corrosion sensor.

Here, with reference to FIG. 1 thru | or FIG. 3, the QCM corrosion sensor of embodiment of this invention is demonstrated. FIG. 1 is a schematic configuration diagram of a QCM corrosion sensor according to an embodiment of the present invention. A pair of sensor electrodes 2 ₁ and 2 ₂ and a sensor electrode 2 ₁ provided on both main surfaces of the crystal disk 1 and the crystal disk _1. , the _second electrode lead-out portion ₃ 1 which connects _{2, 3 2} are provided QCM corrosion sensor body.

The present invention further position spaced 0.5mm~1.0mm radially with respect to the sensor electrodes ₂ 1, _{2 2,} the same material as the sensor electrodes ₂ 1, _{2 2,} the sensor electrodes ₂ 1, _{2 2} Are provided with deterioration measuring conductive members 4 ₁ and 4 ₂ made of concentric arcuate conductive members .

This degradation measuring conductive members 4 _{1, 4 2,} lead portion 5 _{1, 5 2} are provided. In addition, although provided in the front and back in order to balance weight, one side does not need to be used for a measurement. The electrode lead-out portions 3 ₁ and 3 ₂ and the lead-out portions 5 ₁ and 5 ₂ are terminals 6 ₁ and 6 ₂ and a terminal 7 _{1 that} are spring supports integrated with an insulator 8 such as Teflon (registered trademark) interposed therebetween. , it is connected to _{7 2.} This is because the vibration mode is affected when there are two vibration support portions on the left and right sides of the sensor.

The quartz disk 1 is usually an AT-cut quartz disk that vibrates by thickness-shear vibration, and the sensor electrodes 2 ₁ and 2 ₂ may be anything as long as they are conductors excellent in a corrosion reaction against a corrosive gas. Typically, Ag or Cu is used.

In the measurement of corrosive gas at the same time as measuring the corrosive gas environment at QCM corrosion sensor body, for measuring the degradation resistance of the measurement conductive member 4 _1. By monitoring the resistance value, the deterioration degree of the sensor electrode is confirmed in real time, thereby using the resistance value as an index for sensor replacement timing to measure the timing for replacing the QCM corrosion sensor.

  FIG. 2 is an explanatory diagram of the sensor replacement time of the QCM corrosion sensor according to the embodiment of the present invention. As shown in the figure, the frequency change of the QCM sensor changes with time. That is, when the QCM corrosion sensor is exposed to a corrosive environment, the sensor electrode corrodes, and the mass of the sensor electrode increases due to the progress of corrosion. Along with this, the resonance frequency decreases. However, in FIG. 2, the resonance frequency at the start of measurement is the reference (= 0 Hz), and the amount of decrease is shown on the vertical axis.

  Furthermore, if the corrosive environment is continuously measured, the corrosion of the sensor electrode proceeds and the electrode is damaged. When damage to the sensor electrode has progressed to a certain extent, sufficient current cannot be supplied to the circular portions of the front and back of the QCM corrosion sensor facing the sensor electrode, and the QCM corrosion sensor cannot be sensed.

The resistance value of the deterioration measuring conductive member increases with the progress of corrosion. Therefore, a resistance value (sensor replacement index resistance value: R _ref ) as an index for replacing the QCM corrosion sensor is set in advance, and an alarm or the like is notified when it becomes larger than R _ref. Replace the corrosion sensor.

The procedure for setting the sensor replacement index resistance value R _ref is as follows. A sensor having the same specifications as the QCM corrosion sensor used for measurement, that is, a QCM sensor using a crystal disk cut out from the same lumbard by a sensor manufactured by the same structure, material and manufacturing process is prepared.

The resistance value of the conductive member for deterioration measurement is confirmed in a state where the QCM sensor is not exposed to the corrosive gas, and this is set as the initial resistance value. Next, a QCM sensor is inserted into a corrosive gas atmosphere having an appropriate concentration, and the resonance frequency and the resistance value of the deterioration measuring conductive member are measured. The resistance measurement unit may be anything as long as it can measure the resistance change of the electrode for deterioration measurement. For example, a Wheatstone bridge circuit is used.

FIG. 3 is an example of a change in resonance frequency over time, and the resonance frequency decreases (increases as a frequency change) according to the measurement time, but suddenly increases from a certain time as shown in FIG. As shown in FIG. 3B, an irregular change that repeatedly increases and decreases is shown. The resistance value of the conductive member for deterioration measurement at the time when the resonance frequency change with time starts to change in this way becomes the sensor replacement index resistance value. By performing measurement with the above-described configuration apparatus, a sensor failure can be recognized in advance, and sensing can be performed for a long time by replacing the sensor before the failure.

In order to perform continuous sensing for a long time using such a QCM corrosion sensor, a plurality of QCM corrosion sensors are housed in a casing through a partition wall. With exposing the QCM corrosion sensors running in the measurement atmosphere, so as to isolate the QCM corrosion sensor completing QCM corrosion sensors or measurement standby state from the measurement atmosphere, the shutter member is provided, the deterioration measuring conductive member When the resistance value becomes the sensor replacement index resistance value, the operating QCM corrosion sensor is switched to the standby QCM corrosion sensor.

At this time, the resonance frequency measurement unit and the deterioration measurement unit connected to each QCM corrosion sensor may be always turned on, but if only the monitored part is turned on, power consumption can be saved. Further, when the ratio of the resistance value R _{deg of} the deterioration measuring conductive member to the sensor replacement index resistance value R _ref reaches about 0.8, the oscillation circuit and frequency counter of the next QCM corrosion sensor are attached to the housing lid. It is also possible to start and wait while the is closed.

  The resonance frequency during this standby operation period is measured, and if it is significantly different from the basic resonance frequency or unstable, this QCM corrosion sensor is recognized as a failure sensor and is not used for sensing. The QCM corrosion sensor is put on standby. If it can be recognized that it stably resonates at the intended frequency in the standby operation, this QCM corrosion sensor is an operation sensor.

  Also, depending on the type of sensor electrode used, the sensor electrode has a different corrosion mechanism from the initial time after a certain amount of time has elapsed, and the correspondence between the corrosive gas concentration and the increase in the corrosion film thickness is different between the initial time and the subsequent time. There is. In such a case, in the method in which the sensor cell lids are opened one by one and sensing is performed sequentially, when switching to the next QCM corrosion sensor, the corrosion film suddenly increases and the corrosion immediately before the previous QCM corrosion sensor ends. It becomes inconsistent with.

  Therefore, it is necessary to provide a period in which two sensor cell lids are opened simultaneously. After the standby operation of the next QCM corrosion sensor, the sensor cell is opened, the QCM corrosion sensor is exposed, and pre-sensing is performed until reaching a region where the corrosion film thickness of the sensor electrode increases relatively slowly. Actually, since the thickness of the corroded film increases rapidly for about 2 hours at the beginning of the corrosion, the next QCM sensor can be used after pre-sensing for about 5 hours.

  The timing of the next QCM corrosion sensor pre-sensing may be any time as long as the previous QCM corrosion sensor is being sensed. However, it is most reliable and simple to start the sensing of the previous QCM corrosion sensor at the same time as the next QCM corrosion sensor is pre-sensing and when the pre-sensing is finished, the sensor cell lid is closed and the standby operation is performed. It is.

As described above, in the embodiment of the present invention, since the deterioration measuring conductive member is provided in the vicinity of the sensor electrode, the deterioration state of the sensor electrode can be monitored in real time, thereby ensuring a long time. Sensing becomes possible.

Next, a QCM corrosion sensor according to Example 1 of the present invention will be described with reference to FIGS. FIG. 4 is a configuration explanatory diagram of the QCM corrosion sensor element according to the first embodiment of the present invention. The QCM corrosion sensor element body has a diameter of, for example, 8 mm and an AT-cut quartz disk 21 and a pair of Ag films having a diameter of 5 mm and a thickness of 0.1 μm provided on both main surfaces of the quartz disk 21. Sensor electrodes 22 ₁ and 22 ₂ are provided. Further, electrode lead portions 23 ₁ and 23 _{2 made of} an Ag film connected to the sensor electrodes 22 ₁ and 22 _2, and terminals 24 ₁ and 24 ₂ made of Au fixed to the electrode lead portions 23 ₁ and 23 ₂ by soldering are provided. ing. The thickness t of the quartz disk 21 is 0.167 mm in order to oscillate at a fundamental frequency of 10 MHz.

Further, the width is the same as the width of the electrode lead-out portions 23 ₁ and 23 ₂ at a position 0.5 mm away from the sensor electrodes 22 ₁ and 22 ₂ in the radial direction, for example, 1.0 mm and the thickness is 0.1 μm. degradation measuring conductive member 25 1 of Ag _film, 25 ₂ is provided, using one of the degradation measurement conductive member 25 ₁ for the monitoring for measurement. Moreover, the degradation measurement conductive member 25 _1, 25 Ru lead portions 26 ₁ Na from Ag film connected _{2, 26 2,} 26 3, 26 _4, which is fixed by solder to the lead portions 26 _1, 26 ₂ Au Terminals 27 ₁ and 27 ₂ are provided.

The terminals 24 ₁ and 24 ₂ and the terminals 27 ₁ and 27 ₂ are integrated as a spring support 28 with an insulating film made of Teflon (registered trademark) having a thickness of 0.05 mm interposed therebetween. Moreover, it branches at the measurement end side and is implanted in the metal base 29 with a glass hermetic seal.

FIG. 5 is an apparatus configuration diagram of the QCM corrosion sensor according to the first embodiment of the present invention. The terminals 24 ₁ and 24 _{2 serving as} the oscillation circuit connection terminals of the QCM corrosion sensor element include the oscillation circuit 31 and the frequency counter 32. The resonance frequency measuring unit 30 is connected.

On the other hand, the terminal ₂₇ 1 as a degradation measurement circuit connecting terminals of the QCM corrosion sensor element, 27 ₂ Wheatstone bridge circuit 41, a DC power source 42 is connected to the resistance measuring unit 40 comprising a voltmeter 43, degradation measurement conductive member 25 Monitor ₁ resistance change.

The Wheatstone bridge circuit 41 connects QCM corrosion sensor elements in series with R ₄ with bridge resistances R _{1 to} R ₄ . If R ₁ = R ₂ = R ₃ = R ₄ = R, then the resistance R _deg of the deterioration measuring conductive member 25 ₁ is that V is the voltage of the DC power supply 42 and E ₀ is the voltage indicated by the voltmeter 43. ,
R _deg = {4E ₀ / (V-2E ₀ )} × R
It is obtained as Although the DC resistance is measured in the figure, it may be necessary to consider the occurrence of migration of the electrode material. In such a case, the AC resistance value may be measured.

At this time, in advance in advance, obtains the sensor exchange index resistance _{R ref,} and an alarm when the deterioration resistance _{R deg} measurement for the conductive member 25 ₁ has exceeded the sensor exchange index resistance _{R ref,} QCM Replace the corrosion sensor element.

As described above, in the first embodiment of the present invention, since the deterioration measuring conductive member is provided in the vicinity of the sensor electrode, the deterioration is detected and replaced before the sensor becomes faulty and measurement becomes impossible. Therefore, stable measurement for a long time becomes possible.

  Next, a corrosion sensor system according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a conceptual system configuration diagram of the corrosion sensor system according to the second embodiment of the present invention, and the diagram on the left side is a configuration explanatory diagram of the corrosion sensor system, which is shown in a sectional view and a top view. Moreover, the figure on the right side shows the connection state of each QCM corrosion sensor.

As shown in the figure on the left side, in the corrosion sensor system, QCM corrosion sensor elements 20 _{1 to} 204 are accommodated in _four cell chambers 52 provided in a casing 50 partitioned by a partition wall 51, respectively. The upper portion of the casing 50, and a lid 53 having a QCM corrosion sensor element 20 other than ₁ QCM corrosion sensor element opening 54 of 90 ° so as not exposed to the measuring atmosphere during sensing is provided, the lid 53 is driven by a step motor 55 provided at the bottom of the housing 50.

As shown in the figure on the right side, oscillation circuits 31 _{1 to} 31 ₄ , frequency counters 32 _{1 to} 32 ₄ , and resistance measuring units 40 ₁ to 40 ₄ are connected to the QCM corrosion sensor elements 20 _{1 to} 20 _4. Then, the measurement is continuously performed by sequentially switching with the changeover switch 56. The step motor 55, the oscillation circuits 31 _{1 to} 31 ₄ , the frequency counters 32 _{1 to} 32 ₄ , and the resistance measuring units 40 ₁ to 40 ₄ are controlled by a PC (personal computer) 57.

While data of the resonance frequency is sent from the frequency counter ₃₂₁ to 323 ₄ to the PC57, which is stored in a memory in the PC57. Further, the PC 57 compares the resistance value R _deg data of the deterioration measuring conductive member sent from the resistance measuring units 40 ₁ to 40 ₄ with the sensor replacement index resistance value R _ref set in advance by the PC 57.

FIG. 7 is an explanatory diagram of the open / closed state of the sensor cell portion. As shown in the figure, each time the resistance R _deg of the deterioration measuring conductive member of each of the QCM corrosion sensor elements 20 _{1 to} 20 ₄ reaches the sensor replacement index resistance value R _ref , the step motor 55 sequentially opens the lid 53 by 90 °. The QCM corrosion sensor elements 20 _{1 to} 20 ₄ that perform sensing by rotating are sequentially switched.

FIG. 8 is an explanatory diagram of the correlation between switching of the QCM corrosion sensor element, frequency change, resistance change, and step motor current. As shown in the figure, when the resistance value of the deterioration measuring conductive member reaches the sensor exchange index resistance R _ref previously set, switched by driving the step motor to the next QCM corrosion sensor element 20 _2. By repeating this operation sequentially, it becomes possible to perform continuous measurement for a long time.

  Next, a corrosion sensor system according to a third embodiment of the present invention will be described with reference to FIG. 9, and this third embodiment will be described before the QCM corrosion sensor element to be sensed next in the above-described second embodiment before sensing. It is in a standby state. FIG. 9 is an explanatory diagram of the operation of the corrosion sensor system according to the third embodiment of the present invention. FIG. 9 (a) is an explanatory diagram of the open / closed state of the lid, FIG. 9 (b) is an explanatory diagram of a standby state of the next QCM corrosion sensor element, and the upper stage is a frequency change characteristic of the QCM corrosion sensor element during sensing. The lower part is a frequency change characteristic diagram of the waiting QCM corrosion sensor element.

As shown in FIG. 9, first, the sensing of the normal corrosion gas QCM corrosion sensor element 20 _1. At this time, QCM corrosion sensor element 20 ₂ next performs sensing the OFF state.

Time Then, the ratio of the resistance value _{R deg} of QCM corrosion sensor element 20 ₁ of the degradation measurement conductive member during sensing preset to the sensor exchange index resistance _{R ref,} here became 0.8 times in, the following QCM corrosion sensor element 20 ₂ to oN. Incidentally, to measure the resonant frequency during the standby operation period, and materially different frequencies, if unstable confirmed this QCM corrosion sensor element 20 ₂ and the faulty sensors, not used for sensing, further wait operation the following QCM corrosion sensor element 20 _3.

Then, the resistance value _{R deg} of QCM corrosion sensor element 20 ₁ of the degradation measurement conductive member during sensing, when it becomes the same as the sensor exchange index resistance _{R ref,} QCM corrosion sensor element waiting operation 20 Open the lid 53 of the sensor cell ₂ and start sensing.

  In the third embodiment of the present invention, the QCM corrosion sensor element to be sensed next is preliminarily operated in advance and the element characteristics are measured in advance. Therefore, when the QCM corrosion sensor element being sensed fails, Measurement using the QCM corrosion sensor element can be performed without any trouble.

  Next, a corrosion sensor system according to a fourth embodiment of the present invention will be described with reference to FIGS. 10 to 12. In this fourth embodiment, the QCM corrosion sensor element that performs sensing next in the second embodiment is used. Pre-sensing is performed before sensing. FIG. 10 is an explanatory diagram of a corrosion state to which the fourth embodiment of the present invention is applied.

  As shown in FIG. 10, depending on the correlation between the material of the sensor electrode used and the corrosive gas, the corrosion mechanism of the sensor electrode differs from the initial state after a certain amount of time, and the corrosive gas concentration and Corresponding to the increase in corrosion thickness may be different. Such a fact may be confirmed by a prior experiment. For example, the relationship between an Ag electrode and hydrogen sulfide gas corresponds to this fact.

  In such a case, in the method of sensing one by one by opening the lid of the sensor cell one by one, when switching to the next sensor, the corrosion film suddenly increases and becomes inconsistent with the corrosion just before the end of the previous sensor End up.

  Therefore, a period in which two lids of the sensor cell are simultaneously opened is provided, and the QCM corrosion sensor element to be sensed next is turned on to perform pre-sensing. For this operation, two step motors are required instead of one, and two semicircular lids are required.

  FIG.11 and FIG.12 is explanatory drawing of operation | movement of the corrosion sensor system of Example 4 of this invention. 11 (a) and 11 (a) are explanatory diagrams of the open / closed state of the lid, FIG. 11 (b) and FIG. 12 (b) are explanatory diagrams of the operation of the next QCM corrosion sensor element, and the upper part is FIG. 3 is a frequency change characteristic diagram of a QCM corrosion sensor element during sensing, and a lower part is a frequency change characteristic diagram of a waiting QCM corrosion sensor element.

As shown in FIG. 11, first, the sensing of the normal corrosion gas QCM corrosion sensor element 20 _1. At this time, QCM corrosion sensor element 20 ₂ next performs sensing the OFF state.

Time Then, the ratio of the resistance value _{R deg} of QCM corrosion sensor element 20 ₁ of the degradation measurement conductive member during sensing preset to the sensor exchange index resistance _{R ref,} here became 0.8 times in, while closing the cover 53, the following QCM corrosion sensor element 20 ₂ to oN. Incidentally, here, the resonant frequency in the standby operation period is measured, and materially different frequencies, if unstable confirmed this QCM corrosion sensor element 20 ₂ and the faulty sensors, used for sensing without the further wait operation the following QCM corrosion sensor element 20 _3.

Then, as shown in FIG. 12, at expected timing time is about 6 hours to failure is predicted from the resistance value R _deg of QCM corrosion sensor element 20 ₁ of the degradation measurement conductive member during sensing, QCM corrosion open the lid 53 of the sensor element 20 ₂ starts a pre-sensing. Actually, since the thickness of the corroded film increases rapidly for about 2 hours in the initial stage of corrosion, the next sensor can be used after pre-sensing for about 5 hours.

Then, the resistance value _{R deg} of QCM corrosion sensor element 20 ₁ of the degradation measurement conductive member during sensing, when it becomes the same as the sensor exchange index resistance _{R ref,} the lid 53 of the QCM corrosion sensor element 20 ₁ closed, then it starts sensing by QCM corrosion sensor element 20 ₂ waiting operation.

In Embodiment 4 of the present invention, the QCM corrosion sensor element to be sensed next is pre-sensed in advance to perform the initial corrosion, so that stable continuous long-time measurement is possible. In the case where even after the lapse of about 5 hours QCM corrosion sensor element 20 ₁ in the sensing is not faulty, to continue the standby operation by closing the lid 53 of the sensor cell QCM corrosion sensor element 20 ₂ to end the pre-sensing .

In Examples 2 to 4, the number of QCM corrosion sensor elements to be used is four. However, any number of QCM corrosion sensor elements may be used as long as the number is two or more, and the sensor cell lid is provided according to the number to be used. The angle of the opening may be adjusted. In each embodiment, the electrode lead portion is made of the same material as the sensor electrode and the deterioration measuring conductive member , but may be formed of an Au film in order to suppress corrosion of the electrode lead portion.

Here, the following supplementary notes are attached to the embodiments of the present invention including Examples 1 to 4.
(Appendix 1) A quartz microbalance corrosion sensor comprising: a quartz disk; sensor electrodes provided on the front and back sides of the quartz disk; and a deterioration measuring conductive member provided on the front and back sides of the quartz disk.
(Additional remark 2) The said sensor electrode is a disk-shaped electrode, and the said electroconductive member for deterioration measurement is concentric arc-shaped electroconductivity arrange | positioned 0.5 mm-1.0 mm apart in the radial direction with respect to the said sensor electrode. quartz microbalance corrosion sensor according to note 1, which is a member.
(Appendix 3) The spring support connected to the sensor electrode and the spring support connected to the conductive member for deterioration measurement are integrated with an insulating layer interposed therebetween to be integrated. The quartz crystal microbalance corrosion sensor according to 1 or 2
(Supplementary note 4) A plurality of quartz microbalance corrosion sensors according to any one of supplementary notes 1 to 3 are accommodated in a housing through a partition wall, and the quartz microbalance corrosion sensor for measurement is placed in a measurement atmosphere. A shutter member for isolating the quartz microbalance corrosion sensor for standby or the quartz microbalance corrosion sensor for which measurement has been completed from the measurement atmosphere, and opening and closing the shutter member by a measurement signal from the conductive member for deterioration measurement And a switching mechanism for switching from the quartz crystal microbalance corrosion sensor for measurement to the quartz microbalance corrosion sensor for standby in accordance with opening and closing of the shutter member. Sensor system.
(Appendix 5) The shutter member opens and closes to expose the standby crystal microbalance corrosion sensor to the measurement atmosphere when the standby crystal microbalance corrosion sensor is in a pre-sensing state. The corrosion sensor system according to appendix 4, characterized by comprising:
(Supplementary Note 6) and a crystal disc, the sensor electrode provided on the front and back of the quartz disk, the deterioration measuring conductivity of quartz microbalance corrosion sensor and a deterioration measurement conductive member provided on the front and back of the quartz disc A method for measuring a corrosive gas, wherein the corrosion state is monitored by an output from a member .
(Appendix 7) A plurality of quartz microbalance corrosion sensors, comprising a quartz disk, sensor electrodes provided on the front and back of the quartz disk, and a deterioration measuring conductive member provided on the front and back of the quartz disk. The unit is placed in a housing via a partition wall, and the output from the conductive member for deterioration measurement of the quartz microbalance corrosion sensor being measured is compared with a predetermined sensor replacement index resistance value and waits. A method for measuring a corrosive gas, comprising switching to the quartz crystal microbalance corrosion sensor.
(Supplementary note 8) The supplementary note 7 is characterized in that a pre-sensing period is provided by exposing the standby quartz microbalance corrosion sensor to the measurement atmosphere before switching to the standby quartz microbalance corrosion sensor. The corrosive gas measuring method described.

DESCRIPTION OF SYMBOLS 1 Crystal disk 2 ₁ , 2 ₂ Sensor electrode 3 ₁ , 3 ₂ Electrode extraction part 4 ₁ , 4 ₂ Deterioration measurement conductive member 5 ₁ , 5 ₂ Extraction part 6 ₁ , 6 ₂ , 7 ₁ , 7 ₂ Terminal 8 Insulation Body 20 _{1 to} 20 ₄ QCM corrosion sensor element 21 Crystal disk 22 ₁ , 22 ₂ Sensor electrode 23 ₁ , 23 ₂ Electrode extraction portion 24 ₁ , 24 ₂ Terminal 25 ₁ , 25 ₂ Degradation measuring conductive member 26 _{1 to} 26 ₄ lead portions 27 _1, 27 ₂ terminal 28 spring support 29 metal base 30 resonance frequency measurement unit 31, 31 ₁ to 31 ₄ oscillation circuit 32 _{1-32 4} frequency counter 40, 40 ₁ to 40 ₄ resistance measuring unit 41 Wheatstone Bridge circuit 42 DC power supply 43 Voltmeter 50 Housing 51 Bulkhead 52 Cell chamber 53 Lid 54 Opening 55 Step motor 56 Changeover switch 57 PC

Claims (5)

A crystal disk,
Sensor electrodes provided on the front and back of the crystal disk;
A quartz microbalance corrosion sensor comprising: a deterioration measuring conductive member provided on the front and back of the quartz disk. The sensor electrode is a disk electrode;
2. The concentric arc-shaped conductive member , wherein the deterioration measuring conductive member is arranged with a distance of 0.5 mm to 1.0 mm in the radial direction with respect to the sensor electrode. Quartz microbalance corrosion sensor. A plurality of the quartz crystal microbalance corrosion sensors according to claim 1 or 2, wherein each of the quartz microbalance corrosion sensors is housed in a housing through a partition wall,
The quartz microbalance corrosion sensor for measurement is exposed to the measurement atmosphere, and the quartz microbalance corrosion sensor for standby or the shutter member for isolating the quartz microbalance corrosion sensor that has been measured from the measurement atmosphere is provided,
An opening / closing mechanism for opening / closing the shutter member by a measurement signal from the deterioration measuring conductive member, and a quartz crystal microbalance corrosion for standby from the quartz crystal microbalance corrosion sensor for measurement as the shutter member is opened / closed A corrosion sensor system comprising a switching mechanism for switching to a sensor. A crystal disk,
Sensor electrodes provided on the front and back of the crystal disk;
A plurality of quartz microbalance corrosion sensors each including a degradation measurement conductive member provided on the front and back of the quartz disk are disposed in a housing with a partition wall, and the degradation of the quartz microbalance corrosion sensor being measured is measured. A method for measuring a corrosive gas, comprising: comparing the output from the conductive member for measurement with a predetermined sensor replacement index resistance value and switching to the quartz microbalance corrosion sensor waiting.   The corrosion according to claim 4, wherein a pre-sensing period is provided by exposing the waiting crystal microbalance corrosion sensor to the measurement atmosphere before switching to the waiting crystal microbalance corrosion sensor. Gas measurement method.

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