JP5087503B2 - Corrosion monitoring sensor - Google Patents

Description

  The present invention relates to a corrosion monitoring sensor for measuring a corrosion state of a metal to be evaluated in a corrosive environment.

  Some waste incinerators generate electricity by guiding fuel gas to a boiler and operating a steam turbine with high-pressure steam generated by the boiler in order to effectively use waste heat generated by the combustion of waste as an energy source. Since the incineration ash generated in the garbage incinerator contains high-temperature molten salt and the like, if the incineration ash adheres to the heat transfer tube of the boiler, the heat transfer tube made of metal is easily corroded. As an apparatus for measuring the corrosion state of a heat transfer tube (evaluated metal) in such a corrosive environment, a corrosion monitoring sensor using electrochemical measurement is provided (for example, see Patent Document 1).

In this corrosion monitoring sensor, a sample electrode, a counter electrode, and a reference electrode are attached to a part of a wall of a support tube made of metal via an insulating substrate. According to this sensor, the polarization resistance (impedance) at the interface of the sample electrode is measured by measuring the current between the sample electrode and the reference electrode with an AC voltage applied between the sample electrode and the counter electrode from the outside. Is required. Since it is known that this polarization resistance has a predetermined correlation with the corrosion rate, the corrosion rate of the sample electrode can be derived from the polarization resistance based on the correlation.
JP 2005-91281 A

  By the way, the data acquired by the corrosion monitoring sensor may be deviated from the initially assumed corrosion amount depending on the operating condition of the incinerator and the property of the garbage. Therefore, remove the corrosion monitoring sensor from the boiler, measure the amount of corrosion (eg, thickness reduction, weight loss, etc.) of the sample electrode, and correct the accumulated data so that the data at the time of removal matches the measured value. I am doing work.

  When performing the correction, the support tube is cut and the sample electrode is taken out, and the sensor cannot be reused after that, and the correction result cannot be effectively used for the subsequent measurement. In addition, until the correction is performed, the corrosion state must be monitored based on data that may contain an error.

  Therefore, an object of the present invention is to provide a corrosion monitoring sensor that enables correction of acquired data during a monitoring period.

  The present invention has been made in view of the above circumstances, and a corrosion monitoring sensor according to the present invention is a corrosion monitoring sensor in which a sample electrode, a counter electrode, and a reference electrode are provided on a support member, and is the same as the sample electrode. A corrosion test piece made of a material is provided on the support member.

  According to the above configuration, removing the corrosion test piece and actually measuring the corrosion amount is the same as actually measuring the corrosion amount of the sample electrode that is the same material as that, so the sample electrode is not removed from the support member. It becomes possible to grasp the actual amount of corrosion of the electrode. This makes it possible to continue measurement by the corrosion monitoring sensor even after the corrosion specimen is removed to correct the data acquired by the corrosion monitoring sensor, and correct the data acquired from the sensor during the monitoring period. It can be performed appropriately. Therefore, the correction result can be reflected in the subsequent measurement, and accurate measurement can be realized. Further, by adopting a configuration in which the corrosion test piece can be replaced, it is possible to prepare for further correction by attaching the corrosion test piece or a new corrosion test piece to the corrosion monitoring sensor even after restarting the measurement.

  The support member may be made of metal, and the corrosion test piece, the sample electrode, the counter electrode, and the reference electrode may be attached to the support member via an insulating member.

  According to the above configuration, the corrosion test piece that is not an electrode is also attached to the support member via the insulating member, and the environment in which the corrosion test piece is placed (for example, the heat transferred via the insulating member) is Since it becomes the same as it, the corrosion state of a corrosion test piece and a sample electrode can be made to correspond well.

  The corrosion test piece is preferably arranged adjacent to the sample electrode.

  According to the above configuration, the corrosion test piece is adjacent to the sample electrode, and the environment (for example, ambient temperature) where the corrosion test piece is placed is the same as that of the sample electrode. The state can be matched well. In addition, the said corrosion test piece may be arrange | positioned away from the said sample electrode.

  The support member is tubular, and the corrosion test piece has the sample electrode along the longitudinal direction of the support member so that the angular position in the circumferential direction on the outer peripheral surface of the support member is the same as that of the sample electrode. May be arranged side by side.

  According to the above-described configuration, the support member is tubular, and the state of attachment of space suspended matter (for example, incineration ash) to the outer peripheral surface varies depending on the position in the circumferential direction. Since they are attached at the same angular position in the direction, the adhesion state of the space floating material to the corrosion test piece becomes the same as that of the sample electrode, and the corrosion state between the corrosion test piece and the sample electrode can be matched well.

  The corrosion test piece may be formed with an adapter accommodating portion, and a thermocouple adapter that holds a thermocouple may be detachably accommodated in the adapter accommodating portion.

  According to the above configuration, the thermocouple can be easily attached to and detached from the corrosion test piece simply by attaching and detaching the thermocouple adapter to the adapter housing portion, and the corrosion monitoring sensor can be easily reused. it can.

  The thermocouple adapter holds the thermocouple with the tip of the thermocouple exposed, and is positioned with the tip of the thermocouple in contact with the inner wall surface of the adapter housing. It may be.

  According to the said structure, since the front-end | tip part of a thermocouple contacts a corrosion test piece in the state which the thermocouple adapter was positioned by the adapter accommodating part, the contact with a thermocouple and a corrosion test piece is stabilized.

  The corrosion test piece has a cylindrical portion and a test plate portion provided in a flange shape at the tip of the cylindrical portion, and the adapter accommodating portion is on an end surface of the cylindrical portion opposite to the test plate portion. A sleeve-shaped insulating member is externally fitted to the columnar part in a state where the end of the columnar part opposite to the test plate part is exposed, and the end part of the corrosion test piece. Is formed with a pin insertion hole penetrating in a direction perpendicular to the axial direction of the cylindrical portion, and the thermocouple adapter is formed with a pin insertion hole communicating with the pin insertion hole, and the corrosion On the outer peripheral surface of the end portion of the test piece, a locking groove portion is formed at a position farther from the test plate portion than the pin insertion hole, and the pin insertion hole of the corrosion test piece and the thermocouple adapter A pin is inserted through and a snap ring is fitted in the locking groove. Is, the elastic member may be interposed between the end portions exposed to the outside of the cylindrical portion of the pin and the snap ring.

  According to the above configuration, the elastic member supported by the snap ring is pressed against both ends of the pin, so that the pin is prevented from being detached from the pin insertion hole, and the thermocouple adapter is not detached from the adapter accommodating portion. Can be positioned. Further, since the insulating member fitted on the cylindrical portion is disposed between the test plate portion of the corrosion test piece and both ends of the pin, the insulating member can be positioned so as not to be detached from the corrosion test piece. .

  As is apparent from the above description, according to the present invention, measurement by the sensor can be continued even after grasping the actual corrosion amount of the sample electrode in order to correct the data acquired by the corrosion monitoring sensor. Thus, it is possible to appropriately correct the acquired data from the sensor during the monitoring period. Therefore, the correction result can be reflected in the subsequent measurement, and accurate measurement can be realized.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a partial cross-sectional perspective view showing a refuse incineration facility 1 to which a corrosion monitoring sensor according to an embodiment of the present invention is applied. As shown in FIG. 1, the waste incineration facility 1 includes a waste input hopper 2, a waste incinerator 3, a boiler body 4, a water pipe 5 and a superheater pipe 6. The high-temperature combustion gas G discharged by the combustion of the waste D in the waste incinerator 3 is guided to the boiler body 4 to heat the water flowing in the primary heating water pipe 5 to generate steam. The steam flows in the superheater pipe 6 for secondary heating, and the combustion gas G ′ after heating the water pipe 5 further heats the steam in the superheater pipe 6, and the high-temperature and high-pressure steam is generated by the steam turbine for power generation. 7 is supplied.

  A large number of water pipes 5, which are heat transfer pipes connected to the drum 8, are disposed upstream of the boiler body 4. The combustion gas G contains corrosive components such as high-temperature molten salt by burning vinyl chloride or the like contained in the waste D, and the water pipe 5 made of metal is added to the corrosive combustion gas G in a high-temperature environment. Will be exposed. Therefore, in order to estimate and evaluate the corrosion rate of the water pipe 5 and the like, a corrosion monitoring sensor 10 described below is attached to the boiler body 4.

  FIG. 2 is a schematic diagram showing the overall configuration of the corrosion monitoring apparatus 9 using the corrosion monitoring sensor 10 according to the embodiment of the present invention. As shown in FIG. 2, the corrosion monitoring device 9 includes a corrosion monitoring sensor 10, an electrochemical measuring device 15, a personal computer 16, a blower 17, and a flow rate regulator 18. The corrosion monitoring sensor 10 has a support tube 11 (support member) having a detection unit 12 at the tip. The detection unit 12 includes a sample electrode 21, a counter electrode 22, a reference electrode 23, and a corrosion test piece 31 (see FIG. 3), which will be described in detail later.

  The support tube 11 is inserted into the boiler body 4 through an opening 4a formed in the wall of the boiler body 4, and the opening 4a is closed by fixing the flange 13 provided in the support tube 11 to the wall of the boiler body 4. Is done. An electrochemical measuring device 15, a blower 17, and a flow rate regulator 18 connected to the personal computer 16 are connected to a portion of the support tube 11 that protrudes outside the boiler. The electrochemical measuring instrument 15 and the personal computer 16 estimate the corrosion rate of the water pipe 5 (see FIG. 1) based on the signal detected by the detection unit 12. The blower 17 performs temperature management of the detection unit 12 by blowing cooling air into the support tube 11. The flow rate regulator 18 controls the flow rate of the blower 17 in order to approximate the temperature of the detection unit 12 to the temperature of the water pipe 5.

  FIG. 3 is a cross-sectional view of a main part of the corrosion monitoring sensor 10 shown in FIG. FIG. 4 is a plan view of an essential part of the corrosion monitoring sensor 10 shown in FIG. As shown in FIGS. 3 and 4, the support tube 11 of the corrosion monitoring sensor 10 is made of, for example, stainless steel (for example, SUS310S), and a closed wall 11e having a cold air outflow hole 11f is provided at the tip thereof. The support tube 11 may be formed of other corrosion resistant metals such as a nickel base alloy. Moreover, the support tube 11 may be open in the boiler body 4 without providing the closing wall 11e. Four attachment holes 11a to 11d are formed in a row along the longitudinal direction of the support tube 11 on the outer peripheral wall of the tip portion of the support tube 11, and the sample electrodes are provided in the three attachment holes 11a to 11c. 21, the reference electrode 23 and the counter electrode 22 are respectively attached via ceramic substantially cylindrical insulating sleeves 25 to 27 (insulating members).

  The sample electrode 21 is made of carbon steel (for example, STB340) which is the same material as the water pipe 5 which is a metal to be evaluated in the boiler body 4 (see FIG. 1), and has a cylindrical shape having a flange-shaped disk portion at the upper end. Is formed. The counter electrode 22 is made of platinum which forms a pair with the sample electrode 21 and is formed in a cylindrical shape having a flange-shaped disk portion at the upper end thereof. The reference electrode 23 is obtained by filling a mullite Tamman tube, which is a dome-shaped ceramic, with a solvent electrolyte (NaCl, KCl or the like containing 1/10 molar ratio of AgCl) and inserting a silver wire. . The reference electrode 23 is provided at an intermediate position between the sample electrode 21 and the counter electrode 22 and serves as a reference potential for the sample electrode 21.

  The insulating sleeves 25 to 27 are screwed to the support tube 11 and are also fixed by an adhesive. The sample electrode 21 and the counter electrode 22 are fixed to the insulating sleeves 25 and 26 by spot welding. The reference electrode 23 is fixed to the insulating sleeve 27 with an adhesive. The sample electrode 21, the counter electrode 22, and the reference electrode 23 are electrically connected to the electrochemical measuring instrument 15 (see FIG. 1) via electrochemical measurement lead wires 41 to 43 that pass through the internal space of the support tube 11. ing. Further, the sample electrode 21 and a corrosion test piece 31 to be described later are connected to the flow rate regulator 18 (see FIG. 1) via thermocouples 51 to 53 that pass through the internal space of the support tube 11.

  A corrosion test piece unit 30 is attached to the attachment hole 11 d on the most distal end side of the support tube 11. The corrosion test piece unit 30 is disposed adjacent to the sample electrode 21 on the opposite side of the reference electrode 23. Further, the corrosion test piece unit 30 is juxtaposed along the longitudinal direction of the support tube 11 together with the sample electrode 21, the counter electrode 22 and the reference electrode 23, and the angular position in the circumferential direction on the outer peripheral surface of the support tube 11. Is the same as the sample electrode 21. With such a configuration, the environment in which the corrosion test piece 31 of the corrosion test piece unit 30 is placed (for example, the ambient temperature, the incineration ash adherence state, etc.) is the same as that of the sample electrode 21, and therefore the corrosion of the corrosion test piece 31 The state and the corrosion state of the sample electrode 21 are in good agreement.

  5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is an exploded sectional view of the corrosion test piece unit 30 provided in the corrosion monitoring sensor 10 shown in FIG. As shown in FIGS. 5 and 6, the corrosion test piece unit 30 includes a corrosion test piece 31, an insulating sleeve 32, a thermocouple adapter 33, a thermocouple 52, a pin 34, a disc spring 35 (elastic member), and a snap ring 36. ing. The corrosion test piece 31 is made of the same material as the sample electrode 21. The corrosion test piece 31 has a cylindrical portion 31a and a test plate portion 31b provided in a flange shape at the upper end of the cylindrical portion 31a. The test plate portion 31 b is a portion exposed to the outside, that is, the inside of the boiler body 4, and the area of the portion exposed to the outside of the corrosion test piece 31 is the same as the area of the portion exposed to the outside of the sample electrode 21.

  In the cylindrical portion 31a, an adapter accommodating portion 31c is recessed in the lower end surface opposite to the test plate portion 31b. The adapter accommodating portion 31c has a shape in which the upper end surface is tapered upward, and a thermocouple contact portion 31d is further recessed at the apex of the upper end surface. The cylindrical part 31a is formed with a linear pin insertion hole 31e penetrating in a direction (horizontal direction) orthogonal to the axial direction. An annular locking groove portion 31f is formed on the outer peripheral surface of the lower portion of the cylindrical portion 31a below the pin insertion hole 31e.

  The insulating sleeve 32 provided on the corrosion test piece 31 has the same shape and the same size as the insulating sleeve 25 provided on the sample electrode 21. Specifically, the insulating sleeve 32 has a cylindrical portion 32a and a flange portion 32b provided at the tip (upper end) of the cylindrical portion 32a. On the outer peripheral surface of the cylindrical portion 32a, a male screw portion 32c for being screwed into the mounting hole 11d is formed. On the inner peripheral surface of the insulating sleeve 32, a step portion 32 d is formed so that the upper inner diameter is larger than the lower inner diameter. A pair of opposed notches 32e (see FIGS. 4 and 5) are formed on the side surface of the flange portion 32b. Since the notch 32e is disposed so as to face the direction orthogonal to the longitudinal direction of the support tube 11 whose outer surface is a circumferential surface, the notch 32e protrudes slightly above the outer peripheral surface of the support tube 11. (Refer to FIG. 5).

  The thermocouple adapter 33 has a pencil shape with a tapered upper end side that fits in the adapter accommodating portion 31 c of the corrosion test piece 31, and is made of the same material as the corrosion test piece 31. The thermocouple adapter 33 is formed with a through hole 33a penetrating along the axial direction (vertical direction). A thermocouple 52 is inserted into the through-hole 33a, and the thermocouple 52 is attached to the thermocouple adapter 33 with its tip portion exposed, and the tip of the thermocouple 52 is connected to the thermocouple contact portion 31d. It is pressed with a predetermined force. Further, the thermocouple adapter 33 is formed with a linear pin insertion hole 33b communicating with the pin insertion hole 31e of the corrosion test piece 31 at a position avoiding the adapter accommodating portion 31c.

  The pin 34 is a metal rod that can be inserted into the pin insertion holes 31 e and 33 b, and the entire length thereof is smaller than the inner diameter of the mounting hole 11 d of the support tube 11. The snap ring 36 has a horseshoe shape in plan view, and is fitted into the locking groove 31 f of the corrosion test piece 31. The disc spring 35 has an annular shape and has an elastic force directed in the vertical direction in FIG. Further, the outer diameters of the disc spring 35 and the snap ring 36 are smaller than the inner diameter of the mounting hole 11 d of the support tube 11.

  FIG. 7 is a cross-sectional view of the corrosion test piece unit 30 shown in FIG. 6 after assembly. As shown in FIG. 7, in the corrosion test piece unit 30 after assembly, the insulating sleeve 32 is externally fitted to the cylindrical portion 31a with the lower end portion of the cylindrical portion 31a of the corrosion test piece 31 exposed. In this way, the corrosion test piece 31 that is not an electrode is also attached to the support tube 11 via the insulating sleeve 32, so that the environment in which the corrosion test piece 31 is placed (for example, heat transmitted through the insulating sleeve 32) is changed. It becomes the same as that of the electrode 21, and the corrosion state of the corrosion test piece 31 and the corrosion state of the sample electrode 21 match well.

  In a state where the insulation sleeve 32 is externally fitted to the corrosion test piece 31, the test plate portion 31 b is placed on the step portion 32 d from above, and the pin insertion hole 31 e is exposed below the insulation sleeve 32. ing. Moreover, the thermocouple adapter 33 is accommodated in the adapter accommodating part 31c so that attachment or detachment is possible from the downward direction. The tip of the thermocouple 52 exposed at the tip of the thermocouple adapter 33 is in contact with the thermocouple contact portion 31 d that is the inner wall surface of the corrosion test piece 31.

  The pin insertion hole 31e of the corrosion test piece 31 and the pin insertion hole 33b of the thermocouple adapter 33 are in communication with each other, and the pin 34 is inserted into the connected pin insertion holes 31e and 33b. Thus, the insulating sleeve 32 is positioned and held by the pin 34 and the test plate portion 31b, and the thermocouple adapter 33 is positioned and held in the adapter housing portion 31c. Below the both ends of the pin 34 exposed to the outside of the cylindrical portion 31a, a disc spring 35 is disposed so as to externally fit the cylindrical portion 31a. A snap ring 36 is fitted into the locking groove 31f of the cylindrical portion 31a, and the snap ring 36 supports the disc spring 35 from below. As a result, the disc spring 35 presses both ends of the pin 34 upward, and the pin 34 is prevented from coming out of the pin insertion holes 31e and 33b.

  Next, the function of the corrosion monitoring device 9 will be described. As shown in FIGS. 2 and 3, in the corrosion monitoring device 9, the flow controller 18 detects the temperature of the sample electrode 21 of the corrosion monitoring sensor 10 using the thermocouple 51, and the temperature of the sample electrode 21 is that of the water tube 5. The blower volume of the blower 17 is controlled so as to be substantially the same as the temperature. The flow controller 18 detects the temperature of the corrosion test piece 31 using the thermocouple 52 and confirms whether the temperature of the corrosion test piece 31 is substantially the same as the temperature of the sample electrode 21. The flow controller 18 also detects the temperature of the support tube 11 using a thermocouple 53 for reference.

  Since the sample electrode 21 and the corrosion test piece 31 are arranged in the boiler main body 4 similarly to the water pipe 5, the high-temperature molten salt contained in the incinerated ash adheres and corrosion proceeds. In this state, the electrochemical measuring instrument 15 performs measurement using a known AC impedance method in order to obtain the corrosion rate of the sample electrode 21. Specifically, the electrochemical measuring instrument 15 measures the current flowing between the sample electrode 21 and the reference electrode 23 in a state where a minute alternating voltage having a different frequency is applied to the sample electrode 21 and the counter electrode 22. The polarization resistance at the interface of the sample electrode 21 is calculated.

  There is a correlation that the corrosion rate increases as the polarization resistance decreases. The personal computer 16 stores in advance the correlation between the polarization resistance of the member made of the same material as the sample electrode 21 and the corrosion rate. By using the correlation, the corrosion of the sample electrode 21 is calculated from the calculated polarization resistance. Speed is required. The personal computer 16 sequentially stores the obtained corrosion rate data, and also saves the corrosion amount data of the sample electrode 21 obtained by integrating the stored corrosion rate data. Thus, by obtaining the corrosion rate and the corrosion amount of the sample electrode 21, the corrosion rate and the corrosion amount of the water tube 5 in the same environment as the sample electrode 21 can be estimated. In addition, since these data may include measurement errors due to the AC impedance method, if a certain period of time passes and the corrosion rate and corrosion amount data are accumulated, the corrosion test is performed as follows. The actual amount of corrosion of the piece 31 is measured, and the data is corrected based on the measured value.

  FIG. 8 is a cross-sectional view of the main part showing a state in which the corrosion test piece unit 30 is removed from the corrosion monitoring sensor 10 shown in FIG. As shown in FIG. 8, when actually measuring the corrosion amount of the corrosion test piece 31, the corrosion monitoring sensor 10 is removed from the boiler body 4, and the corrosion test piece unit 30 is taken out from the mounting hole 11 d of the support tube 11. Specifically, the corrosion test piece unit 30 is taken out from the mounting hole 11d by screwing the notch 32e (see FIGS. 4 and 5) of the insulating sleeve 32 with a tool and turning it. Next, after removing the snap ring 36 and the disc spring 35, the pin 34 is extracted from the pin insertion holes 31e and 33b, whereby the thermocouple adapter 33 and the insulating sleeve 32 are removed from the corrosion test piece 31 (see FIG. 6).

  Next, the scale attached to the surface of the test plate portion 31b of the corrosion test piece 31 is chemically removed with a chemical, and the corrosion amount (for example, the thickness reduction or weight loss) of the corrosion test piece 31 is actually measured. Then, the corrosion amount data sequentially stored in the personal computer 16 is shift-corrected so that the corrosion amount data immediately before removing the corrosion test piece unit 30 from the support tube 11 matches the actual measurement value. Then, after replacing the corrosion test piece 31 with a new one, the corrosion test piece unit 30 is reassembled and attached to the attachment hole 11d of the support tube 11, and the corrosion monitoring sensor 10 is attached to the boiler body 4 again to continue measurement. .

  According to the configuration described above, removing the corrosion test piece 31 and measuring the corrosion amount is the same as measuring the corrosion amount of the sample electrode 21 that is the same material as that, so the sample electrode 21 is supported. It is possible to grasp the actual amount of corrosion of the sample electrode 21 without removing it from the tube 11. This makes it possible to continue measurement by the corrosion monitoring sensor even after the corrosion specimen is removed to correct the data acquired by the corrosion monitoring sensor, and correct the data acquired from the sensor during the monitoring period. It can be performed appropriately. Therefore, the correction result can be reflected in the subsequent measurement, and accurate measurement can be realized. In addition, since the thermocouple adapter 33 is configured to be attached to and detached from the adapter accommodating portion 31c of the corrosion test piece 31, the thermocouple 52 can be easily attached to and detached from the corrosion test piece 31, and the corrosion monitoring sensor 10 It can be easily reused.

  In this embodiment, the insulating sleeves 25 to 27 and 32 are provided on the electrodes 21 to 23 and the corrosion test piece 31 respectively, but the electrodes 21 to 23 and the corrosion test piece 31 are insulated from each other by one insulating member. It is good also as composition to do. In the present embodiment, the support tube 11 is tubular, but the support member to which the electrodes 21 to 23 and the corrosion test piece 31 are attached is not limited to a tubular shape. In the present embodiment, the example in which the corrosion monitoring device 9 is applied to the garbage incineration facility 1 has been described. However, in the facility where the metal to be evaluated exists in a corrosive environment (for example, a soda recovery boiler or a coal fired boiler). In this case, the corrosion monitoring device 9 can be applied. Moreover, in this embodiment, although the metal to be evaluated is the water pipe 5, the superheater pipe 6 may be the metal to be evaluated. In the present embodiment, the substantially cylindrical insulating sleeves 25 to 27 and 32 are used as the insulating member, but insulating members having other shapes may be used.

As described above, the corrosion monitoring sensor according to the present invention can appropriately correct the acquired data from the sensor during the monitoring period. Therefore, the correction result can be reflected in the subsequent measurement, and accurate measurement can be realized.
It is beneficial to apply widely to measure the corrosion state of the metal under evaluation in a corrosive environment.

It is a fragmentary sectional perspective view which shows the refuse incineration facility to which the corrosion monitoring sensor which concerns on embodiment of this invention is applied. It is the schematic which shows the whole structure of the corrosion monitoring apparatus using the corrosion monitoring sensor which concerns on embodiment of this invention. It is principal part sectional drawing of the corrosion monitoring sensor shown in FIG. It is a principal part top view of the corrosion monitoring sensor shown in FIG. It is the VV sectional view taken on the line of FIG. FIG. 4 is an exploded cross-sectional view of a corrosion test piece unit provided in the corrosion monitoring sensor shown in FIG. 3. It is sectional drawing after the assembly of the corrosion test piece unit shown in FIG. It is principal part sectional drawing which shows the state which removed the corrosion test piece unit from the corrosion monitoring sensor shown in FIG.

Explanation of symbols

10 Corrosion monitoring sensor 11 Support tube (support member)
15 Electrochemical measuring device 21 Sample electrode 22 Counter electrode 23 Reference electrode 25-27, 32 Insulation sleeve (insulation member)
31 Corrosion test piece 31a Cylindrical part 31b Test plate part 31c Adapter accommodating part 31e Pin insertion hole 31f Locking groove part 33 Thermocouple adapter 33b Pin insertion hole 34 Pin 35 Disc spring (elastic member)
36 Snap Ring 51-53 Thermocouple

Claims (7)

A corrosion monitoring sensor in which a sample electrode, a counter electrode, and a reference electrode are provided on a support member,
A corrosion monitoring sensor, wherein a corrosion test piece made of the same material as the sample electrode is provided on the support member. The support member is made of metal,
The corrosion monitoring sensor according to claim 1, wherein the corrosion test piece, the sample electrode, the counter electrode, and the reference electrode are attached to the support member via an insulating member.   The corrosion monitoring sensor according to claim 1, wherein the corrosion test piece is disposed adjacent to the sample electrode. The support member is tubular;
The corrosion test piece is arranged side by side with the sample electrode along a longitudinal direction of the support member so that an angular position in a circumferential direction on the outer peripheral surface of the support member is the same as that of the sample electrode. The corrosion monitoring sensor according to any one of 1 to 3. The corrosion test piece is formed with an adapter accommodating portion,
The corrosion monitoring sensor according to any one of claims 1 to 4, wherein a thermocouple adapter that holds a thermocouple is detachably accommodated in the adapter accommodating portion.   The thermocouple adapter holds the thermocouple with the tip of the thermocouple exposed, and is positioned with the tip of the thermocouple in contact with the inner wall surface of the adapter housing. The corrosion monitoring sensor according to claim 5. The corrosion test piece has a cylindrical portion and a test plate portion provided in a flange shape at the tip of the cylindrical portion,
The adapter accommodating portion is recessed on the end surface of the cylindrical portion opposite to the test plate portion,
A sleeve-like insulating member is externally fitted to the cylindrical portion with the end portion of the cylindrical portion opposite to the test plate portion exposed.
The end portion of the corrosion test piece is formed with a pin insertion hole penetrating in a direction perpendicular to the axial direction of the cylindrical portion, and the thermocouple adapter has a pin insertion hole communicating with the pin insertion hole. Is formed,
On the outer peripheral surface of the end of the corrosion test piece, a locking groove is formed at a position farther from the test plate than the pin insertion hole,
A pin is inserted into the pin insertion hole of the corrosion test piece and the thermocouple adapter, a snap ring is fitted into the locking groove, and both ends exposed to the outside of the cylindrical portion of the pin and the snap ring The corrosion monitoring sensor according to claim 5 or 6, wherein an elastic member is interposed therebetween.

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