JP2008241599A - Temperature-sensing meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature-sensing meter which is capable of suppressing amount of wear of a fixing part for preventing vibration of a thermocouple sheath and a tip fixing part and enhancing the reliability. <P>SOLUTION: The thermocouple sheath 13 is formed into a shape of a cylinder and has a temperature-sensing part 14 which senses the temperature of the tip. The thermocouple sheath 13 is inserted in a protective tube 15 so that the temperature-sensing part 14 is located in the tip of the protective tube 15; the fixing part 16 is contacted to the inside of the protecting tube 15 and supports a profile of the thermocouple sheath 13; the tip fixing part 17 is contacted with the inside of the protecting tube 15 and supports the tip part of the thermocouple sheath 13; and the axial length of the tip fixing part 17 is formed larger than the inside diameter of the protective tube 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a temperature detector.

  An example of the temperature detector is a gas turbine exhaust gas thermometer that detects a gas turbine exhaust gas temperature. Since the gas turbine exhaust gas temperature detected by the gas turbine exhaust gas thermometer is used for gas temperature control, trip interlock, etc., the gas turbine exhaust gas thermometer is a very important instrument.

  A plurality of gas turbine exhaust gas thermometers are installed so as to penetrate from the outside of the flue toward the inside along the circumference of the exhaust gas flue at the gas turbine outlet.

  FIG. 2 is an explanatory diagram of the installation state of the temperature detector. As shown in FIG. 2, in detecting the exhaust gas temperature at the gas turbine outlet, a plurality of temperature detectors are formed from the outside to the inside of the exhaust gas flue 11 along the circumference of the exhaust gas flue 11 at the gas turbine outlet. 12 is installed to pierce. FIG. 2 shows a case where 20 temperature detectors 12 are installed. The temperature detector 12 is arranged so that a temperature sensing unit for sensing the temperature of the hot fluid is located inside the flue 11, and a terminal head is attached to the outside of the flue 11.

  The exhaust gas at the gas turbine outlet is a high-temperature fluid at about 600 ° C., and the temperature detector 12 is exposed to this exhaust gas flow. Therefore, the temperature detector 12 vibrates with the flow of the exhaust gas. Therefore, a protective tube is installed from the outside to the inside of the flue 11 and a thermocouple sheath is inserted into the protective tube so that the temperature sensing unit is positioned inside the flue 11.

  As shown in FIG. 3, the temperature detector 12 for detecting the gas turbine exhaust gas temperature detects the temperature of the gas turbine exhaust gas in the exhaust gas flue 11 inserted into the protection tube 15 and the protective tube 15 that pierces the exhaust gas flue. It is comprised from the thermocouple sheath 13 to measure. Further, the opposite side of the protective tube 15 from the tip opening is located outside the exhaust gas flue 11, and a terminal head (not shown) is attached.

  Since the protective tube 15 and the thermocouple sheath 13 inserted therein vibrate under the influence of the flow of the gas turbine exhaust gas, the thermocouple sheath 13 is supported on the inner surface of the protective tube 15 by a ring-shaped fixing material 16. The fixing member 16 is installed at positions A1 to A4 in which the length of the thermocouple sheath 13 is equally divided. Further, the tip of the thermocouple sheath 13 is supported on the inner surface of the tip opening of the protective tube 15 by a ring-shaped tip fixing member 17, thereby preventing vibration of the gas turbine exhaust gas thermometer. A temperature sensing unit 14 that senses the temperature is provided at the tip of the thermocouple sheath 13.

Here, as a temperature detector, a thermocouple sheath used for a moisture separator heater is inserted into a thermocouple sheath protective tube to form a thermocouple sheath device, and the thermocouple sheath is supported by a shape memory alloy support, There is one that facilitates insertion of the thermocouple sheath into the protective tube and prevents wear of the thermocouple sheath due to vibration of the thermocouple sheath protective tube due to steam flow (see, for example, Patent Document 1).
Japanese Utility Model Publication No. 4-104539

  However, in the technique of Patent Document 1, a shape memory alloy is used as a fixing material for the thermocouple sheath. However, the shape recovery temperature of the shape memory alloy in a TiNi alloy that has been put to practical use is 353 K or less. A shape memory alloy material that can be used at a high temperature of about 600 ° C. (773 K) has not been put to practical use. For this reason, stainless steel is generally used as the current thermocouple sheath fixing material.

  Here, when the state of the temperature detector 12 for detecting the temperature of the gas turbine exhaust gas used for one year was investigated, the fixing member 16 and the tip fixing member 17 installed for preventing the vibration of the thermocouple sheath 13 were worn. It was found that the thermocouple sheath 13 needs to be replaced. Table 1 shows the survey results of the temperature detector 12 shown in FIG. 3 used for one year, and shows the wear rates of the fixing member 16 of the thermocouple sheath 13 and the tip fixing member 17.

In Table 1, the temperature detector 12 for detecting the gas turbine exhaust gas temperature is as follows. The material of the fixing member 16 and the tip fixing member 17 of the thermocouple sheath 13 and the material of the protective tube 15 are the same, and the fixing member 16 is installed at a position where the length of the thermocouple sheath 13 is equally divided. A distal end fixing member 17 is provided at the distal end of the sheath 13. The distal end fixing member 17 has a length in the axial direction that is smaller than the inner diameter of the protective tube (axial length / protective tube inner diameter = 0.794).

  As shown in Table 1, the closer to the tip of the thermocouple sheath 13, the higher the wear rate, and the tip portion fixing member 17 has the highest wear rate. The wear rate of the tip fixing member 17 is 0.214, which exceeds the index value (0.149) of the wear rate of replacement of the thermocouple sheath 13. When the wear rate of the fixing member 16 and the tip fixing member 17 exceeds the index value (0.149), vibration of the thermocouple sheath 13 is not prevented, and the temperature detector 12 is used in this state. If the operation is continued, the reliability of the measured value is lowered, so that the thermocouple sheath 13 needs to be replaced.

  As described above, the conventional temperature detector 12 requires replacement of the thermocouple sheath 13 after being used for about one year, so that it is required to extend the maintenance period of the temperature detector. Yes.

  An object of the present invention is to provide a temperature detector that can suppress the amount of wear of the fixing member for preventing vibration of the thermocouple sheath and the amount of wear of the tip end fixing member and improve the reliability.

  According to a first aspect of the present invention, there is provided a temperature detector according to a first aspect of the present invention, wherein the thermocouple sheath is formed in a cylindrical shape and has a temperature sensing portion at the tip, and the thermocouple sheath is positioned so that the temperature sensing portion of the thermocouple sheath is located at the tip. A protective tube into which the sheath is inserted; a fixing member that contacts the inner surface of the protective tube and supports the side surface portion of the thermocouple sheath; and an inner surface of the protective tube that supports the distal end portion of the thermocouple sheath And a tip end fixing member having an axial length larger than the inner diameter of the protective tube.

  According to a second aspect of the present invention, there is provided the temperature detector according to the first aspect of the present invention, wherein the protective tube is formed in a cylindrical shape, and the thermocouple sheath is positioned so that a temperature sensing portion of the thermocouple sheath is located at a tip opening. Is inserted.

  According to a third aspect of the present invention, there is provided the temperature detector according to the first aspect of the present invention, wherein the protective tube is hollow and the outer appearance is formed in a cylindrical shape, and the temperature sensing of the thermocouple sheath is formed in a hemispherical shape at the tip. The thermocouple sheath is inserted so that the portion is positioned.

  A temperature detector according to a fourth aspect of the present invention is the temperature detector according to any one of the first to third aspects, wherein the fixing member is provided at a node portion of the natural vibration waveform of the thermocouple sheath. To do.

  The temperature detector according to a fifth aspect of the present invention is the temperature detector according to any one of the first to fourth aspects, wherein the fixing member and the tip end fixing member are made of a metal having a hardness lower than that of the metal of the protective tube. It is used.

  According to the present invention, the axial length of the distal end fixing member that supports the distal end portion of the thermocouple sheath on the inner surface of the protective tube is formed to be longer than the inner diameter of the protective tube. Shaking of the thermocouple sheath caused by vibration can be suppressed, and the wear rate of the tip fixing member can be suppressed.

  The fixing material that supports the side surface of the thermocouple sheath on the inner surface of the protective tube is provided at the node of the natural vibration waveform of the thermocouple sheath. The wear rate of the member can be suppressed. Further, since the fixing member and the tip end fixing member are made of a metal having a lower hardness than the metal of the protective tube, the wear of the fixing member and the tip end fixing member that are easy to replace becomes larger than the wear of the protective tube. As a result, maintenance is facilitated, so that the repair cost can be reduced and the reliability of the temperature detector is improved.

  FIG. 1 is a configuration diagram of a temperature detector according to an embodiment of the present invention. As shown in FIG. 1A, the thermocouple sheath 13 of the temperature detector 12 is formed in a columnar shape (bar shape), and has a temperature sensing portion 14 for sensing temperature at the tip. The protective tube 15 is formed in a cylindrical shape, for example, and is installed on the outer peripheral surface of the screw exhaust flue 11 in a screwed manner. The thermocouple sheath 13 is inserted into the cylindrical protective tube 15, and is arranged so that the temperature sensing unit 14 at the distal end is exposed from the distal end opening of the protective tube 15 to the inside of the flue 11. On the other hand, the opposite side of the protective tube 15 from the tip opening is located outside the exhaust gas flue 11, and a terminal head (not shown) is attached.

  A plurality of fixing materials 16 are provided at intervals on the side surface of the thermocouple sheath 13. The intervals at which the plurality of fixing members 16 are provided are the locations B1 to B6 of the node portions of the natural vibration waveform of the thermocouple sheath 13. That is, in order to avoid vibration amplification due to exhaust gas vibration and the thermocouple sheath 13 natural vibration, the natural frequency of the thermocouple sheath 13 is measured, and the fixing material 16 is installed at the positions B1 to B6 of the nodes of the vibration waveform. To do. As a result, the plurality of fixing members 16 abut on the inner surface of the protective tube 15, support the side surface portion of the thermocouple sheath 13 on the inner surface of the protective tube 15, and suppress vibration in the protective tube 15 of the thermocouple sheath 13. Like to do.

  Further, a tip fixing member 17 is provided at the tip of the thermocouple sheath 13. As shown in FIG. 1B, the axial length Y of the protective tube 15 is formed to be longer than the inner diameter X of the protective tube 15. As a result, the distal end fixing member 17 abuts against the inner surface of the protective tube 15, supports the distal end portion of the thermocouple sheath 13 on the inner surface of the protective tube 15, and suppresses the axial shake of the thermocouple sheath 13.

  In order to suppress the axial fluctuation of the thermocouple sheath 13, it is better that the length Y in the axial direction of the tip fixing member 17 is larger. However, if the length Y in the axial direction of the tip fixing member 17 is increased, the tip The part fixing member 17 and the inner surface of the protective tube 15 are easily fixed. When the tip fixing member 17 and the protective tube 15 are fixed, the thermocouple sheath 13 cannot be easily replaced. Therefore, the length Y in the axial direction of the tip fixing member 17 is limited to a size that does not allow the tip fixing member 17 and the protective tube 15 to be fixed. The length Y in the axial direction of the tip fixing member 17 is preferably limited to not more than twice the inner diameter X of the protective tube 15.

  Here, the plurality of fixing members 16 and the tip portion fixing member 17 are formed of a metal having a lower hardness than the metal of the protective tube 15. The fixing material 16 and the tip fixing material 17 are preferably of the same type and the same material in order to prevent corrosion due to contact with the protective tube 15, but in the embodiment of the present invention, the fixing material 16 or As the tip fixing member 17, a material having a slightly lower hardness than the protective tube 15 is selected. For example, when the protective tube 15 is SUS316, SUS304 or the like is adopted for the fixing material 16 and the tip portion fixing material 17. As a result, the wear of the fixing member 16 and the tip fixing member 17 that are easy to replace is greater than the wear of the protective tube 15, and maintenance is facilitated.

Table 2 shows the results of investigation when the temperature detector according to the embodiment of the present invention is used for one year, and shows the wear rate of the fixing member 16 and the tip fixing member 17 of the thermocouple sheath 13. In Table 2, the temperature detector 12 is as follows. The material of the protective tube 15 is SUS316, and the fixing material 16 of the thermocouple sheath 13 and the material of the tip end fixing material 17 are SUS304 having a hardness lower than that of SUS316, and the position B1 of the node portion of the natural vibration waveform of the thermocouple sheath 13 is used. The six fixing members 16 are installed in B6, and the tip end fixing member 17 at the tip of the thermocouple sheath has an axial length Y that is 1.59 times the inner diameter X of the protective tube 15.

  As shown in Table 2, the wear rate (0.029) of the tip fixing member 17 of the thermocouple sheath 13 is smaller than the index value (0.149) of the replacement wear rate of the thermocouple sheath 13, and the wear rate is the highest. Even the fixing member 16 at the large fixing member position B5 has a wear rate (0.034), which is smaller than the index value (0.149) of the wear rate of replacement of the thermocouple sheath 13. Therefore, in the temperature detector according to the embodiment of the present invention, the wear amount of the vibration preventing fixing member 16 and the tip fixing member 17 of the thermocouple sheath 13 can be suppressed, and the maintenance period of the temperature detector is reduced. Can be extended.

  In the above description, the protective tube 15 is formed in a cylindrical shape, and the temperature sensing portion 14 of the thermocouple sheath 13 is located at the opening of the distal end of the protective tube 15. May be formed in a cylindrical shape, and the temperature sensing portion 14 of the thermocouple sheath 13 may be positioned inside the hemispherical shape at the tip of the protective tube 15. When the temperature sensing unit 14 of the thermocouple sheath 13 is positioned at the distal end opening of the protective tube 15, the temperature detection sensitivity is improved, but the lifetime of the temperature sensing unit 14 is shortened, so the temperature detection sensitivity is prioritized. Adopt if you want to. Conversely, when the temperature sensing unit 14 of the thermocouple sheath 13 is positioned inside the hemispherical shape at the tip of the protective tube 15, the lifetime of the temperature sensing unit 14 is extended, but the temperature detection sensitivity is deteriorated. Therefore, it is adopted when priority is given to the life of the temperature detector 14.

  According to the embodiment of the present invention, the axial length of the distal end fixing member 17 that supports the distal end of the thermocouple sheath 13 is formed on the inner surface of the protective tube 15 to be larger than the inner diameter of the protective tube 15. Therefore, the contact area between the tip of the thermocouple sheath 13 and the inner surface of the protective tube 15 increases. Accordingly, since the vibration in the flow of the gas turbine exhaust gas is suppressed with the large contact area, the axial fluctuation of the thermocouple sheath 13 can be suppressed, and the wear rate of the tip fixing member 17 can be suppressed.

  Further, since the fixing member 16 that supports the side surface portion of the thermocouple sheath 13 on the inner surface of the protective tube 15 is provided at the node portion of the natural vibration waveform of the thermocouple sheath 13, the thermocouple at the installation portion of the fixing member 16 is provided. Shaking of the sheath 13 can be suppressed, and the wear rate of the fixing member 16 can be suppressed.

  Further, since the fixing member 16 and the tip fixing member 17 are made of metal having a hardness lower than that of the protective tube 15, maintenance is facilitated. That is, since the wear of the fixing member 16 and the tip fixing member 17 that are easy to replace is greater than the wear of the protective tube 15, maintenance is facilitated. As a result, the amount of wear of the fixing member 16 and the tip fixing member 17 is suppressed and maintenance is facilitated, so that the repair cost can be reduced and the reliability of the temperature detector is improved.

The block diagram of the temperature detector concerning embodiment of this invention. Explanatory drawing of the installation state of the temperature detector concerning embodiment of this invention. The block diagram of the conventional temperature detector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Exhaust gas flue, 12 ... Temperature detector, 13 ... Thermocouple sheath, 14 ... Temperature sensing part, 15 ... Protection tube, 16 ... Fixing material, 17 ... Tip part fixing material

Claims (5)

  A thermocouple sheath formed in a columnar shape and having a temperature sensing portion at the tip, a protection tube into which the thermocouple sheath is inserted so that the temperature sensing portion of the thermocouple sheath is located at the tip, and the protection tube A fixing member that contacts the inner surface of the thermocouple sheath and supports the side surface portion of the thermocouple sheath; and an inner surface of the protective tube that supports the distal end portion of the thermocouple sheath and has an axial length longer than the inner diameter of the protective tube. A temperature detector comprising a tip fixing member formed in a large length.   The temperature detector according to claim 1, wherein the protection tube is formed in a cylindrical shape, and the thermocouple sheath is inserted so that a temperature sensing portion of the thermocouple sheath is positioned at a tip opening.   The protective tube is characterized in that the inside of the protective tube is hollow and the appearance is formed in a cylindrical shape, and the thermocouple sheath is inserted so that the temperature sensing part of the thermocouple sheath is located inside the hemispherical shape of the tip. The temperature detector according to claim 1.   The temperature detector according to any one of claims 1 to 3, wherein the fixing member is provided at a node portion of the natural vibration waveform of the thermocouple sheath.   The temperature detector according to any one of claims 1 to 4, wherein the fixing member and the tip end fixing member are made of a metal having a hardness lower than that of the metal of the protective tube.

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