JP4365796B2 - Gas analyzer - Google Patents

Description

  The present invention relates to a gas analyzer that measures, for example, a predetermined component contained in a gas to be measured.

  Conventionally, it is discharged from various furnaces in steelmaking, other industrial furnaces, boilers, etc. according to the principle of oxygen concentration cell using electrochemical reaction using a solid electrolyte such as zirconia with oxygen ion conductivity at high temperature It is known to detect the oxygen concentration (or oxygen partial pressure) in the combustion exhaust gas and control the combustion state of these furnaces and boilers. The gas to be measured, such as combustion exhaust gas from an industrial furnace, which is a measurement target of a conventional oxygen sensor using such an electrochemical reaction, flows in layers in a passage such as a flue, so the depth of the measurement point Depending on the oxygen concentration, the value varies greatly. Therefore, a plurality of oxygen sensors are arranged at a predetermined interval in the depth direction with respect to the flow of the gas to be measured, and the oxygen partial pressure or the oxygen concentration at a location where the measurement depth directions are different from each other is obtained. A so-called multi-point gas analyzer has been conventionally proposed (see, for example, Patent Document 1).

  For example, the following configuration is known as such a multipoint gas analyzer. That is, as shown in FIG. 11, the gas analyzer 100 includes a main body box 101 disposed outside the flue, a main pipe 102 extending from the main body box 101 and inserted into the flue, and a peripheral wall of the main pipe 102. A plurality of detachable gas sensors 103 (only one is shown in FIG. 11). The main pipe 102 is inserted into the main pipe insertion port 105 of the flue wall 104 in an incinerator or the like, and the main pipe 102 is formed at the tip of the main pipe insertion port 105 via a flange portion 102a provided near the main body box 101. The flange portion 105a is fixed. A packing 106 is interposed between the flange portions 102a and 105a, and the packing 106 ensures airtightness inside and outside the flue.

  Each gas sensor 103 is arranged at predetermined intervals in the tube axis direction of the main pipe 102, and each gas sensor 103 detects the gas to be measured in the flue. That is, each gas sensor 103 is an oxygen sensor using a solid electrolyte such as zirconia ceramics having oxygen ion conductivity as a sensor element (not shown). Zirconia ceramics become an oxygen concentration cell in which oxygen ions easily move in the crystal structure in a red-hot state and generate a voltage due to a difference in oxygen partial pressure between the inner and outer surfaces. For example, when the atmosphere is brought into contact with the inside of the sensor element and the gas to be measured is brought into contact with the outside, a voltage based on the oxygen concentration in the atmosphere is generated.

The gas sensor 103 includes the sensor element, a heater (not shown) for heating the sensor element, and a temperature sensor (not shown) such as a thermocouple for detecting the temperature of the sensor element, which are provided integrally. Yes. Lead wires 107 for sensor output extraction, heater power supply, and thermocouple output extraction are drawn out from the base end portion of each gas sensor 103, and each lead wire 107 passes through the inside of the main pipe 102 and is connected to the main body box 101. And is connected to an external control device (not shown) via a terminal block in the main body box 101. This control device keeps the temperature of the sensor element constant by turning on / off the power supply to the heater based on the temperature of the sensor element detected by the temperature sensor. The voltage generated in the sensor element is input to the control device via the sensor output lead 107, and the control device obtains the oxygen concentration contained in the gas to be measured in the flue based on the input voltage. .
Japanese Patent Publication No. 7-99364

  In the conventional gas analyzer 100, the gas sensor 103 may be replaced for some reason such as deterioration of the sensor element. At that time, the lead wire 107 corresponding to the gas sensor 103 to be exchanged may be broken and disconnected. In particular, the heater power supply lead wire 107 tends to be broken because it tends to be deteriorated by energization. When the lead wire is broken, it is necessary to replace not only the gas sensor 103 but also the broken lead wire 107. In addition, the lead wire 107 of another gas sensor 103 that does not need to be replaced may be broken and disconnected.

  However, there were the following problems in that case. That is, each lead wire 107 is inserted into the gland packing 108 on the main body box 101 side in the main pipe 102. By applying and curing silicon 109 between the gland packing 108 and the main pipe 102 and between the gland packing 108 and each lead wire 107, airtightness between the main pipe 102 and the main body box 101 is ensured. Further, since the silicon 109 is cured, all the lead wires 107 drawn from the gas sensors 103 are integrally fixed together with the gland packing 108. A holding member 110 is mounted on the main body box 101 side of the gland packing 108, and movement of the gland packing 108 toward the main body box 101 side is restricted by the holding member 110.

  Since such a configuration is adopted, in the conventional gas analyzer, not only the broken lead wire 107 but also all the healthy lead wires 107 drawn from other gas sensors 103 that do not need to be replaced are replaced. There is a need to. That is, in order to replace the lead wire 107 drawn from the gas sensor 103 to be replaced, it is necessary to break the airtight structure between the main tube 102 and the main body box 101 by the gland packing 108 and the silicon 109. After replacement of the gas sensor 103, it is necessary to apply and cure silicon 109 between the gland packing 108 and the main pipe 102 and between the gland packing 108 and each lead wire 107, and to reconstruct the airtight structure. there were. After the reconstruction of the airtight structure, it was necessary to check whether the airtightness between the main body box 101 and the main pipe 102 was ensured. As described above, the replacement work of the gas sensor 103 is troublesome.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a gas analyzer capable of simplifying the replacement work of the gas sensor.

  The invention according to claim 1 is included in a main body box, a main pipe extending from the main body box and inserted into the flue, and a gas to be measured that is detachably attached to a peripheral wall of the main pipe and flows in the flue. A plurality of gas sensors for detecting a predetermined component and a plurality of lead wires led out from each of the gas sensors. The lead wires are introduced into the main body box through the main pipe and the leads. In the gas analyzer configured to analyze the gas to be measured based on the output from each gas sensor taken out from the wire, a plurality of lead wires drawn out from a single gas sensor are set as one unit, and each gas sensor A plurality of corresponding lead wires are inserted into sealing tubes provided corresponding to the respective gas sensors, and the sealing tubes are detachably fixed to the side walls of the main body box. The gist of the thing.

  According to a second aspect of the present invention, in the first aspect of the present invention, a flange member having an equilateral triangular plate shape is provided on the outer peripheral surface of the sealing tube, and the sealing tube passes through the center thereof. The flange member of each sealing tube is arranged so that one side of a pair of adjacent flange members is parallel to each other, and the sealing tube is detachably fixed to the side wall of the main body box via the flange member. The summary is as follows.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a through hole that communicates the inside of the main pipe with the inside of the flue is formed in the tip wall of the main pipe, and the through hole is formed in the through hole. The gist is that one end of a tube body having both ends opened is connected from the inner surface side of the tip wall, while the other end side is opened in the main tube while being bent in a direction intersecting the tube axis of the main tube. And

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein a main body box fixing member for fixing the main body box is provided at a base end portion of the main pipe. In addition, a flange portion for fixing the main pipe to the flue wall of the flue is provided on the tip side of the main body box fixing member, and a reference is provided between the flange portion of the main pipe and the main body box fixing member. The gist is that a gas inlet is provided.

(Function)
According to the first aspect of the present invention, a plurality of lead wires drawn out from a single gas sensor are used as one unit, and a plurality of units of lead wires corresponding to each gas sensor are provided corresponding to each gas sensor. Since the sealing tube is inserted through the sealing tube and detachably fixed to the side wall of the main body box, the lead wire can be replaced for each gas sensor. In other words, when the gas sensor is exchanged, the lead wire of the gas sensor to be exchanged may be broken. In this case, the lead wire needs to be exchanged. At that time, it is not necessary to replace all the lead wires of each gas sensor, and it is only necessary to replace the one unit lead wire including the lead wire where the breakage or the like has occurred. Even at the time of replacement, the lead wires are bundled by being inserted into the sealing tube for each unit, so that the attaching / detaching operation to the side wall of the main body box is also easy. Therefore, the replacement work of the gas sensor can be simplified when the lead wire is broken.

  According to the invention described in claim 2, in addition to the operation of the invention described in claim 1, the sealing tube can be easily fixed to the side wall of the main body box by using the flange member. The flange member of the sealing tube is formed in a triangular plate shape and is provided so that the sealing tube penetrates the center thereof. And each flange member is each arrange | positioned so that one side of a pair of adjacent flange member may mutually become parallel. Thereby, each flange member can be assembled to such an extent that each sealing pipe can be inserted into the main pipe. Incidentally, since the lead wire from each gas sensor passes through the main pipe and is introduced into the main body box, each sealing pipe is inevitably inserted into the main pipe.

  As the shape of the flange member, various shapes such as a circle, a square, a rectangle and the like can be considered in addition to the regular triangle in the present invention. However, if the flange members have other shapes, even if each sealing tube is inserted into the main tube, the flange members interfere with each other, making it difficult to attach them. For example, when the flange member is formed in a square plate shape, for example, when a sealing tube having the same outer diameter is made to penetrate the center of the flange member, the center of the square and the center to the one side of the square And the distance from the center of the equilateral triangle to the one side of the equilateral triangle, the distance from the center of the equilateral triangle to the one side is smaller. The same applies to the case where the flange member has a circular shape or a rectangular shape. Therefore, in order to arrange the flange members closer to each other, it is desirable to form the flange members in a regular triangle shape as in the present invention.

  By the way, as the gas sensor, the product of the pressure in the flue and the predetermined component concentration of the gas to be measured in the flue, the pressure in the transmitter and the predetermined component concentration of the reference gas supplied into the transmitter Many devices that output a voltage based on the ratio to the product of are used. For this reason, it is necessary to make the pressure in the flue and the pressure in the main pipe the same. If the pressure in the flue and the pressure in the main pipe become the same, the pressure in the flue and the pressure in the main pipe can be ignored, and the gas to be measured can be determined from the voltage output from the gas sensor and the predetermined component concentration of the reference gas. It is possible to obtain the predetermined component concentration.

  Against this background, according to the invention described in claim 3, in addition to the action of the invention described in claim 1 or 2, the inside of the flue and the inside of the main pipe have through holes (tubes). Therefore, the pressure in the flue and the pressure in the main pipe are the same. Therefore, the pressure in the flue and the pressure in the main pipe can be ignored, and the predetermined component concentration in the gas to be measured can be obtained from the voltage output from the gas sensor and the predetermined component concentration in the reference gas. .

  In addition, the gas to be measured flowing in the flue often contains foreign matters such as dust, and there is a possibility that the foreign matter may enter the main pipe through a through hole formed in the tip wall of the main pipe. However, in the present invention, since the tubular body bent in the direction intersecting the tube axis of the main pipe is connected to the through hole from the inner surface side of the tip wall, the entry of the foreign matter into the main pipe is prevented. It is suppressed. That is, since the bending of the tube body becomes a resistance, the foreign matter that has entered the tube body through the through hole is less likely to pass through the tube body.

  According to the invention described in claim 4, in addition to the operation of the invention described in any one of claims 1 to 3, the main pipe to which the main body box is fixed has a flue through the flange portion. Easily fixed to the flue wall that makes up. In adopting the gas sensor described above, in the present invention, the introduction port of the reference gas is provided between the flange portion of the main pipe and the main body box fixing member, so that, for example, the introduction port is formed on the outer peripheral surface of the flange portion. The formation is easier than in the case of doing so.

  According to the present invention, since the lead wires bundled for each gas sensor can be exchanged as a unit, for example, when replacing one gas sensor and a lead wire drawn from the gas sensor, the lead wire is drawn from a gas sensor that does not need to be exchanged. There is no need to replace other lead wires. Therefore, the replacement work of the gas sensor can be simplified.

  Hereinafter, the present invention is a gas analyzer that detects and analyzes a predetermined component contained in a gas to be measured such as exhaust gas that is attached to an exhaust pipe of an engine, boiler, industrial furnace, etc. and flows through a flue in the exhaust pipe. A specific embodiment will be described with reference to FIGS. 1 to 10A, 10B, and 10C.

  As shown in FIG. 1, a cylindrical main pipe insertion port M projects from a flue wall W, which is a pipe wall of the exhaust pipe, and an annular flange portion Ma is formed at the outer peripheral edge of the distal end of the main pipe insertion port M. Is formed. And the gas analyzer 11 is attached to the flue wall W using this flange part Ma. The gas analyzer 11 includes a terminal box 12 and a cylindrical main pipe 13 that extends from one side of the terminal box 12 and is inserted into the flue.

<Supervisor>
A flange portion 15 is formed on the proximal end side of the main pipe 13, and a plurality of calibration gas supply ports 15 a (only one is shown in FIG. 1) are formed in the flange portion 15. The calibration gas supply ports 15a are provided in the same number as the gas sensor holding portions 21 described later.

  The main pipe 13 is inserted into the main pipe insertion port M from the distal end side. Then, with the seal member 16 interposed between the outer surface of the flange portion Ma of the flue wall W and the inner surface of the flange portion 15 of the main pipe 13, a bolt 17 is inserted from the flange portion 15 side, and the bolt The main pipe 13 is fixed to the flue wall W by tightening a nut 18 to 17. The seal member 16 sandwiched between the flange portions Ma and 15 in close contact with the inside and outside of the flue, that is, the airtightness between the flange portions Ma and 15 is ensured. As shown in FIG. 2, two of the bolts 17 are eyebolts 17a (only one is shown in FIG. 2). Both eyebolts 17a are used to suspend and support the gas analyzer 11 when the gas analyzer 11 is attached to and detached from the flue wall W.

  As shown in FIG. 1, gas sensor holding portions 21 are arranged at predetermined intervals in the tube axis direction of the main pipe 13 on the outer peripheral surface on the front end side of the flange portion 15 of the main pipe 13, and a gas sensor is provided therein. ing. Each gas sensor holding portion 21 is covered with a filter cover 22. Further, on the outer peripheral surface of the main pipe 13, an inspection port lid 23 is attached to the opposite side of the filter cover 22 so as to correspond to each gas sensor holding portion 21. Further, a main tube lid 24 is attached to the tip of the main tube 13. The main pipe 13 is attached so that each gas sensor holding portion 21 (filter cover 22) faces the downstream direction of the flow of the gas to be measured.

  A plurality of calibration gas introduction pipes 26 (only one is shown in FIG. 1) are disposed on the outer peripheral surface of the main pipe 13 via a plurality of support members 25. The same number of calibration gas introduction pipes 26 as the gas sensor holding portions 21 are provided. One end of the calibration gas introduction pipe 26 is connected to a calibration gas supply port 15 a formed in the flange portion 15, and the other end is similarly connected to the gas sensor holding portion 21.

  As shown in FIG. 2, a square plate-like terminal box fixing member 27 is provided on the outer peripheral surface of the base end portion (outer end portion) of the main pipe 13. In the terminal box fixing member 27, four female screw portions 27a are formed around the proximal end side opening 13a of the main pipe 13, and a plurality (eight in this embodiment) are provided on the outer side of each female screw portion 27a. An internal thread portion 27b is formed. The main pipe 13 is fixed to the outer surface of the side wall of the terminal box 12 via a terminal box fixing member 27. The structure for fixing the terminal box fixing member 27 and the terminal box 12 will be described in detail later.

  A packing 28 is interposed between the terminal box fixing member 27 and the side wall outer surface of the terminal box 12, and airtightness between the main pipe 13 and the terminal box 12 is secured by the packing 28. Further, a reference gas introduction port 29 projects from the outer peripheral surface of the main pipe 13 between the flange portion 15 and the terminal box fixing member 27. The reference gas introduction port 29 is connected to a reference gas supply source such as a compressor (not shown). A reference gas (for example, the atmosphere) from the reference gas supply source is supplied into the main pipe 13 through a reference gas introduction port 29.

<Gas sensor>
As shown in FIG. 4, attachment holes 31 for the gas sensor holding part 21 are formed in the pipe wall of the main pipe 13 at predetermined intervals in the pipe axis direction of the main pipe 13. The part 21 is fixed. Each gas sensor holding portion 21 incorporates a gas sensor (not shown). This gas sensor is an oxygen sensor using a solid electrolyte such as zirconia ceramics having oxygen ion conductivity as a gas sensor element. Zirconia ceramics become an oxygen concentration cell in which oxygen ions easily move in the crystal structure in a red-hot state and generate a voltage due to a difference in oxygen partial pressure between the inner and outer surfaces. For example, a voltage based on the oxygen concentration in the atmosphere is generated by bringing the gas sensor into contact with a reference gas (oxygen concentration known) and the gas to be measured (oxygen concentration unknown). The gas sensor includes a gas sensor element, a heater (not shown) for heating the gas sensor (more precisely, a gas sensor element), a temperature sensor (not shown) such as a thermocouple for detecting the temperature of the gas sensor element, and these are integrated. Configured as a sensor unit.

  Incidentally, the gas sensor is more precisely the product of the pressure in the flue and the oxygen concentration of the gas to be measured in the flue, the pressure in the main pipe 13 and the oxygen concentration of the reference gas supplied into the main pipe 13. A voltage based on the ratio to the product is output. However, as will be described later, in this embodiment, since the inside of the flue and the inside of the main pipe 13 are configured to communicate with each other, the pressure in the flue and the pressure in the main pipe 13 are the same. For this reason, in this embodiment, the pressure in the flue and the pressure in the main pipe 13 can be ignored.

  As shown in FIG. 5 (a), the filter 32 is exposed on the outer end surface of the gas sensor holding part 21, and a covered cylindrical filter cover 22 is provided outside the gas sensor holding part 21 so as to cover the filter 32. Screwed into the end. As shown in FIG. 4, a space 22 a is formed inside the filter cover 22 so that the filter 32 is exposed when the filter cover 22 is attached to the gas sensor holding portion 21. The filter cover 22 communicates with each other through a through hole 22b formed in the side wall.

  The gas to be measured flowing in the flue is introduced into the space 22 a through the through hole 22 b of the filter cover 22, and further reaches the gas sensor built in through the filter 32. At this time, foreign matter such as dust flowing together with the gas to be measured is filtered by the filter 32, so that the foreign matter does not reach the gas sensor. Further, since the filter 32 is covered with the filter cover 22, it is avoided that the foreign matter strikes the filter 32 and the clogging of the filter 32 is suppressed.

  Further, a reference gas introduction port (not shown) is formed at the inner end portion of the gas sensor holding portion 21, and a part of the reference gas supplied into the main pipe 13 flows from the proximal end side to the distal end side of the main pipe 13. In the process of flowing, the gas is introduced into the gas sensor holding part 21 from the reference gas inlet and is brought into contact with the gas sensor. The reference gas in contact with the gas sensor is led out again from the reference gas inlet into the main pipe 13 and flows to the tip side of the main pipe 13.

  As shown in FIG. 4, two lead wires 33a for taking out sensor outputs and two lead wires 33b for supplying heater power are respectively provided from the inner ends of the gas sensor holding portions 21 (more precisely, gas sensors). And two lead wires 33c for extracting the thermocouple output are drawn out. The lead wires 33 a, 33 b, and 33 c that are drawn out are introduced into the terminal box 12 through the main pipe 13. Each lead wire 33a, 33b, 33c introduced into the terminal box 12 is connected to an external control device (not shown) via a terminal block 74 described later disposed in the terminal box 12. The control device keeps the temperature of the gas sensor element constant by turning on / off the power supply to the heater based on the temperature of the gas sensor element detected by the temperature sensor. The voltage generated in the gas sensor element is input to the control device via a sensor output lead wire 33a. Based on the input voltage, the control device determines the oxygen concentration of the gas to be measured in the flue.

  As shown in FIG. 4, a calibration gas introduction port 21a is formed on the side wall at the outer end of each gas sensor holding portion 21, and the calibration gas introduction tube 26 (shown in FIG. 4) is formed in the calibration gas introduction port 21a. Abbreviation) is connected. The calibration gas supplied from the calibration gas introduction pipe 26 comes into contact with the gas sensor, and is then discharged from the space 22a into the flue through the filter 32. The gas sensor element of each gas sensor holding unit 21 is appropriately calibrated using the calibration gas supplied via the calibration gas introduction pipe 26. That is, the error of the gas sensor is corrected with reference to the reference (reference gas oxygen concentration).

<Inspection palate>
As shown in FIG. 4, an inspection port 34 is arranged and formed on the opposite side of each attachment port 31 on the tube wall of the main tube 13. The inspection port lids 23 are detachably attached to the respective inspection ports 34, whereby each inspection port 34 is closed. The inspection port lid 23 is removed when the gas sensor holding unit 21 is inspected, and the gas sensor holding unit 21 is inspected through the exposed inspection port 34.

<Main pipe lid>
As shown by a two-dot chain line in FIG. 7B, an opening 35 is formed at the tip of the main pipe 13. A main tube lid 24 is screwed to the tip (inner end) of the main tube 13, and the opening 35 is closed by the main tube lid 24. The main tube lid 24 constitutes the tip wall of the present invention. As shown in FIG. 7A, a through hole 24a is formed at the center of the main tube lid 24, and a bent tube 37 formed in a J shape is connected to the through hole 24a from the inside. . That is, the bent tube 37 is a tube body that is open at both ends, and one end of the bent tube 37 is connected to the main tube lid 24 in a cantilevered state from the inner surface side, while the other end side is also in a direction intersecting the tube axis of the main tube 13 In this embodiment, it is opened in the main pipe 13 while being bent toward the inner surface side of the main pipe lid 24. The inside of the flue and the inside of the main pipe 13 communicate with each other through the bent pipe 37.

  Accordingly, the pressure in the flue is equal to the pressure in the main pipe. More specifically, if the pressure in the flue increases, the pressure in the main pipe 13 also increases. Conversely, if the pressure in the flue decreases, the pressure in the main pipe 13 also decreases. Thus, the through hole 24a (more precisely, the bent pipe 37) of the main pipe lid 24 has a pressure adjusting function for synchronizing the pressure in the flue and the pressure in the main pipe 13 (reference gas pressure). The reference gas supplied from the reference gas inlet 29 on the proximal end side of the main pipe 13 is discharged into the flue through the bent pipe 37.

<Terminal box>
Next, the terminal box 12 will be described. As shown in FIG. 3, the terminal box 12 has a rectangular frame-shaped terminal box main body 41 and two covers 42 and 42 attached to both sides of the terminal box main body 41 opened (only one is shown in FIG. 3). ) And packings 43, 43 interposed between both sides of the terminal box body 41 and the covers 42, 42, respectively.

  As shown in the figure, openings 41a and 41a are formed in opposite side portions of the terminal box body 41, respectively. Quadrilateral annular flange portions 44, 44 are provided at the peripheral portions of the two openings 41a, 41a, respectively, and a plurality of insertion holes 44a are formed in both flange portions 44, 44. On the other hand, the cover 42 is formed by cutting out four corners of a square flat plate and bending four side edges inward, and includes a square flat plate-shaped cover body 42a and four covering walls 42b. Further, in the cover 42 (more precisely, the cover main body 42a), a plurality of insertion holes 42c are formed in the vicinity of the base end portion of each covering wall 42b.

  The packings 43, 43 are formed in a square ring shape, and the covers 42, 42 are overlapped from the outside of the terminal box body 41 so that the packings 43, 43 are sandwiched between the flanges 44, 44. It is matched. Then, a plurality of bolts 45 (only one is shown in FIG. 3) are inserted into the insertion hole 42c of the cover 42 and the insertion hole 44a of the flange portion 44 from the outside of the cover 42, and nuts are inserted at their tips. Both covers 42, 42 are fixed to the terminal box body 41 by tightening 46. The two openings 41a and 41a of the terminal box body 41 are closed by the covers 42 and 42, respectively. In addition, airtightness between the terminal box body 41 and the outside is ensured by the packing 43 interposed between the covers 42 and 42 and the flange portions 44 and 44.

  As shown in FIG. 6, in the state where the covers 42 and 42 are attached to the side portion of the terminal box body 41, the respective covering walls are provided so that the outer peripheral edge portion of the packing 43 and the outer peripheral edge portion of the flange portion 44 can be covered. The protrusion height from the inner surface of the cover main body 42a of 42b is set. The inner surface (side surface of the terminal box body 41 side) of the packing 43 is covered by the flange portion 44, the outer surface (side surface of the packing 43 on the cover 42 side) is covered by the cover body 42a, and the side edge portion is covered by the covering wall 42b. As a result, it is possible to suppress light such as sunlight from the outside from hitting the packing 43.

  Incidentally, when the covering wall 42b is not formed, the inner and outer surfaces of the packing 43 are covered with the flange portion 44 and the cover body 42a, respectively, but the flange portion 44 and the cover 42 (more precisely, the cover body 42a) The outer peripheral edge of the packing 43 is exposed to the outside, and the exposed portion can be irradiated with light. In the present embodiment, the outer peripheral edge of the packing 43 is covered with the covering wall 42b, thereby suppressing the irradiation of light such as sunlight to the outer peripheral edge of the packing 43.

  Here, the fixing structure of the terminal box fixing member 27 and the terminal box 12 will be described in detail. That is, as shown in FIG. 3, a communication hole 47 is formed at the center of one side wall of the terminal box body 41, and the inner diameter of the communication hole 47 is substantially the same as the inner diameter of the proximal end side opening of the main pipe 13. Is set to In addition, as shown in FIG. 2, a plurality of (four in the present embodiment) through holes 48 are formed around the communication hole 47 on one side wall of the terminal box body 41. Further, a plurality (eight in this embodiment) of insertion holes 49 are formed on the outer side. The communication hole 47, each through hole 48, and each insertion hole 49 are arranged so as to coincide with the proximal end side opening 13 a, each female screw part 27 a, and each female screw part 27 b of the main pipe 13. A plurality of bolts 50 are inserted into the respective insertion holes 49 from the inside of the terminal box 12, and are tightened to the female screw portions 27 b of the terminal box fixing member 27, whereby the terminal box fixing member 27 is connected to the side wall of the terminal box 12. It is fixed to.

<Sealing tube fixing member>
As shown in FIG. 3, a sealing tube fixing member 61 is fixed to the inner surface of the one side wall to which the terminal box fixing member 27 is fixed in the terminal box main body 41. That is, the sealing tube fixing member 61 is formed in a square plate shape, and insertion holes 62 are formed in the four corners of the sealing tube fixing member 61, respectively. Each insertion hole 62 is disposed so as to coincide with each through hole 48 on the one side wall. Then, a bolt 63 (only one is shown in FIG. 3) is inserted into each insertion hole 62 and each through hole 48 from the inside of the terminal box body 41, and each female thread portion of the terminal box fixing member 27 shown in FIG. By tightening to 27a, the sealing tube fixing member 61 is fixed to the inner surface of the one side wall.

  As shown by a chain line in FIG. 8, an annular groove 64 is formed on the back surface (the side surface on the one side wall side) of the sealing tube fixing member 61, and the groove 64 is combined with FIG. 9A. As shown, an O-ring 65 is attached. When the bolt 63 is tightened, the O-ring 65 is crushed between the inner surface of the one side wall, so that airtightness between the one side wall and the sealing tube fixing member 61 is secured.

  As shown in FIG. 8, four sealing tube insertion holes 66 are formed in the center of the sealing tube fixing member 61. Each of the sealing tube insertion holes 66 is arranged and formed so that two are arranged in the vertical and horizontal directions. Further, each sealing tube insertion hole 66 can be accommodated inside the groove 64, and the one side wall can be communicated with each insertion hole 62 of the sealing tube fixing member 61 and each through hole 48 being aligned. It is arranged and formed so as to be within a range corresponding to the hole 47.

  On the surface of the sealing tube fixing member 61 (side surface opposite to the one side wall), three female screw portions 67 are formed around each sealing tube insertion hole 66. The three female threaded portions 67 respectively corresponding to the respective sealing tube insertion holes 66 are arranged so as to form an equilateral triangle when their central points are connected by a straight line. Each female thread portion 67 is formed by two equilateral triangles formed by connecting the center points of three female thread portions 67 respectively corresponding to a pair of sealing tube insertion holes 66 adjacent in the vertical direction in FIG. Are arranged so that the sides facing each other are parallel to each other.

  Between the two insertion holes 62 and 62 that are spaced apart along two side edges (in this embodiment, the left side edge and the right side edge) that are located on opposite sides of the sealing tube fixing member 61. The two female screw portions 68 are formed so as to be separated from each other along both side edges.

<Terminal block>
As shown in FIG. 3, a terminal block support member 71 is fixed to the surface of the sealing tube fixing member 61. That is, the terminal block support member 71 includes a pair of arm members 72 and 72 and a pair of flat plate-shaped support tables 73 and 73 fixed between the arm members 72 and 72. The arm member 72 is formed in a band shape, and a fixing portion 72a extending in a direction orthogonal to the extending direction of the arm member 72 (vertical direction in FIG. 3) is provided at one end of the arm member 72 side. It protrudes toward the direction. Insertion holes 72b and 72b are formed in the upper and lower ends of the fixing portion 72a, respectively. Both support bases 73, 73 are fixed by welding or the like between the upper and lower portions of both arm members 72, 72 in FIG. The terminal block support member 71 configured integrally as described above inserts a bolt (not shown) into each insertion hole 72b from the inside of the terminal box body 41 and inserts the bolt into each female screw portion 68 of the sealing tube fixing member 61. It is fixed to the surface of the sealing tube fixing member 61 by tightening.

  Two terminal blocks 74 are fixed to the surface (upper surface) of one support base 73 fixed between the upper row parts of both arm members 72 and 72 in FIG. Further, by providing the other support base 73 fixed between the descending portions in FIG. 3, the terminal block support member 71 is formed into a rectangular tube shape, thereby ensuring the overall strength of the terminal block support member 71. . In addition, the two terminal blocks 74 can also be fixed to the surface (lower surface) of the other support base 73 fixed between the descending portions of both arm members 72, 72.

<Sealing tube>
As shown in FIG. 9A, sealing tubes 81 (only two are shown in FIG. 3) are inserted and fixed in the four sealing tube insertion holes 66 of the sealing tube fixing member 61, respectively. . Each sealing tube 81 is provided corresponding to each gas sensor, and the sealing tube 81 is formed in a cylindrical shape in which both ends are hermetically sealed. A total of 24 lead wires 33a, 33b, 33c drawn out from each gas sensor by 6 pieces correspond to the sealed pipe 81 corresponding to the 6 lead wires 33a, 33b, 33c drawn out from one gas sensor as a unit. It is inserted in an airtight manner.

  As shown in FIG. 9B, in each sealing tube 81, the six lead wires 33 a, 33 b, and 33 c are regularly arranged circumferentially (annular) along the inner surface of the sealing tube 81. ing. Each sealing tube 81 is filled with an insulating material 81a such as magnesium oxide (so-called magnesia). As a result, the arrangement of the lead wires 33a, 33b, and 33c in each sealing tube 81 is maintained, and the insulation between the lead wires 33a, 33b, and 33c in each sealing tube 81, and the sealing. Insulation between the stop tube 81 and each of the lead wires 33a, 33b, 33c is ensured.

<Flange member>
As shown in FIG. 9A, a flange member 82 is fixed near one end (outer end) of the sealing tube 81. The flange member 82 is formed in a regular triangular plate shape as shown in FIG. As shown in FIG. 10A, an insertion hole 83 through which the sealing tube 81 can be inserted is formed at the center (center) of the flange member 82, and a plurality of holes are formed around the insertion hole 83. (Three in this embodiment) through-holes 84 are formed. Each through hole 84 is a set of three formed so as to correspond to the three apexes of the triangular flange member 82 and around the sealing tube insertion hole 66 of the sealing tube fixing member 61. It is arranged and formed so as to coincide with the female screw portion 67.

  Further, as shown in FIG. 10B, a stepped portion 85 is formed on the peripheral edge of the opening portion of the insertion hole 83 on one surface of the flange member 82, and the stepped portion 85 has a stepped portion as shown in FIG. An O-ring 86 is attached as shown in FIG. The flange member 82 configured as described above is configured so that the stepped portion 85 faces the distal end side of the sealing tube 81 (the insertion side of the sealing tube 81 into the sealing tube insertion hole 66). It is inserted and fixed to. That is, the flange member 82 is formed in the shape of a regular triangular plate, and the flange member 82 is provided so that the sealing tube 81 passes through the center thereof. Then, the sealing tube 81 having the flange member 82 fixed to the proximal end side is inserted into the sealing tube insertion hole 66 of the sealing tube fixing member 61 from the distal end side, and the outer side of each through-hole 84 of the flange member 82. Then, the bolt 87 is inserted and tightened to the female thread portion 67 of the sealing tube fixing member 61, thereby being fixed to the sealing tube fixing member 61. As the bolt 87 is tightened, the O-ring 65 is crushed to ensure airtightness between the sealing tube fixing member 61 and the flange member 82.

  As shown in FIG. 8, the four flange members 82 are arranged so that there are two columns and two rows. In addition, the flange members 82 are arranged in close proximity so that opposite sides of the pair of flange members 82 and 82 adjacent in the column direction are parallel to each other. The flange members 82 are collected near the center of the sealing tube fixing member 61 to such an extent that all the sealing tubes 81 inserted through the respective sealing tube insertion holes 66 can be inserted into the main tube 13. ing.

  As the shape of the flange member 82, various shapes such as a circle, a square, a rectangle and the like can be considered in addition to the regular triangle in the present embodiment. However, when the flange members 82 have other shapes, even if the sealing tubes 81 are inserted into the main tube 13, the flange members 82 interfere with each other and are difficult to attach. For example, when the flange member 82 is formed in a square plate shape, for example, when the sealing tube 81 having the same outer diameter is made to penetrate the center of the flange member 82, the center of the square and the square from the center are square. When the distance to one side is compared with the center of the regular triangle and the distance from the center to one side of the regular triangle, the distance from the center of the regular triangle to the one side is smaller. The same applies to the case where the flange member 82 has a circular shape or a rectangular shape. Therefore, in order to arrange the flange members 82 closer to each other, it is desirable to form the flange members 82 in a regular triangle shape as in the present embodiment.

<Lead wire drawer>
As shown in FIG. 3, the lead wires 33a, 33b, and 33c drawn from the end portions of the sealing tubes 81 that protrude into the terminal box 12 are connected to the gas analyzer through the terminal blocks 74 and 74, respectively. 11 control devices. More specifically, a total of 24 lead wires 33a, 33b, 33c drawn from the gas sensor holding portions 21 are connected to the terminal blocks 74, 74, and correspond to the lead wires 33a, 33b, 33c. Another lead wire (not shown) is connected. As shown in FIG. 3, the other lead wires protrude from the side wall (upper wall in FIG. 3) adjacent to the one side wall to which the terminal box fixing member 27 is fixed in the terminal box body 41. The lead-out port 12b is led out of the terminal box 12 and connected to the control device.

<Operation of gas analyzer>
Next, the operation of the gas analyzer configured as described above will be described. Four gas sensor holding portions 21 (more precisely, gas sensors) attached at predetermined intervals in the pipe axis direction of the main pipe 13 are arranged in the flow of the gas to be measured such as in the flue, and the flue wall W The oxygen concentration of the gas to be measured is detected at four locations with different distances from the inner surface. That is, during measurement of the gas to be measured, the reference gas is always supplied into the main pipe 13 via the reference gas inlet 29, and the voltage from each gas sensor holding unit 21 is based on the oxygen concentration of the reference gas. Is output. The control device of the gas analyzer 11 controls a control target device such as a boiler (combustion control) based on the voltage output from each gas sensor (for example, an average value of each output voltage is obtained and based on the average value). Etc.)

<Replacement of gas sensor>
By the way, in the gas analyzer 11 as described above, the gas sensor may need to be replaced for some reason such as deterioration of the gas sensor element built in the gas sensor. At that time, the lead wires 33a, 33b, 33c drawn from the gas sensor may be broken. In such a case, it is necessary to replace not only the gas sensor but also the broken lead wire. Further, when the lead wire of another normal gas sensor is broken during the replacement work, it is also necessary to replace the broken lead wire.

  Hereinafter, replacement work of the gas sensor and the lead wires 33a, 33b, and 33c in that case will be described. In the present embodiment, a case where only one of the four gas sensors is replaced will be described.

<When removing gas sensor and lead wires 33a, 33b, 33c>
When replacing the gas sensor and the lead wires 33a, 33b, 33c, first, the bolts 45 of the terminal box 12 are removed, and at least one of the covers 42, 42 is removed. Then, a connection line with the control device connected to the terminal block 74 located inside through the opening 41a, a calibration gas supply pipe (not shown) connected to the calibration gas supply port 15a, and the reference gas introduction port 29 are connected. Remove the connected reference gas introduction pipe (not shown). Thereafter, the bolt 17 and the nut 18 are removed, and the connection between the flange portion Ma of the main pipe insertion port M and the flange portion 15 of the main pipe 13 is released. Then, the main pipe 13 is pulled out from the main pipe insertion port M and removed from the flue wall W. Next, the inspection port lid 23 corresponding to the gas sensor to be replaced is removed, the inspection port 34 is opened, and the lead wires 33a, 33b, 33c of the gas sensor to be replaced are cut halfway through the opened inspection port 34. To do. Thereafter, the gas sensor to be replaced is removed from the gas sensor holding unit 21.

  When the lead wires 33a, 33b, and 33c need to be replaced due to the occurrence of breakage or the like, the following is performed. That is, the sealing tube fixing member 61 is removed by removing the three bolts 87 fixing the flange member 82 of the sealing tube 81 corresponding to the gas sensor to be replaced via the opening 41a to the sealing tube fixing member 61. The sealing tube 81 is released from the sealing tube insertion hole 66 of the sealing tube fixing member 61. Along with this, the lead wires 33a, 33b, 33c inserted through the sealing tube 81 are also pulled out from the sealing tube insertion hole 66.

<During installation of gas sensor and lead wires 33a, 33b, 33c>
When the lead wires 33a, 33b, and 33c are not exchanged without occurrence of breakage or the like, the gas sensor and the lead wires 33a, 33b, and 33c are attached after the gas sensor removal operation is completed as described above. In that case, a new gas sensor in place of the removed gas sensor is attached and fixed to the removed gas sensor holding portion 21, and the lead wires 33a, 33b, 33c drawn from the new gas sensor and the lead wires 33a, 33a, 33b and 33c are connected using a connector or the like (not shown).

  When the lead wires 33a, 33b, and 33c are also replaced due to occurrence of breakage or the like, a sealing tube insertion hole into which the removed sealing tube 81 is inserted instead of the removed sealing tube 81 is used. 66. Specifically, the end of each lead wire 33a, 33b, 33c connected to the gas sensor (that is, the connector) is inserted into the sealing tube insertion hole 66, and the sealing tube 81 is inserted from the distal end side thereof. Insert into the sealing tube insertion hole 66. Then, with the three through holes 84 of the flange member 82 aligned with the three female screw portions 67 of the sealing tube fixing member 61, bolts 87 are inserted into the through holes 84 from the outside of the flange member 82, respectively. The flange member 82 is fixed to the sealing tube fixing member 61 by tightening to the portion 67. As a result, the sealing tube 81 is fixed to the terminal box 12 with its distal end inserted into the main tube 13.

  Then, the end portions of the lead wires 33a, 33b, and 33c inserted into the main pipe 13 are connected to the lead wires 33a, 33b, and 33c drawn from the replaced gas sensor by using a connector or the like (not shown). Finally, the inspection port lid 23 is attached to the inspection port 34 and the connection line with the control device is connected to the terminal block 74. Thereafter, the removed cover 42 is attached to the terminal box body 41, and the calibration gas supply pipe and the reference gas introduction pipe are connected to complete the replacement operation of the gas sensor.

  As described above, in this embodiment, the six lead wires 33a, 33b, and 33c of the gas sensor for each gas sensor holding unit 21 are inserted into the sealing tube 81 as a unit, and the sealing tube 81 is inserted into the terminal box 12. (To be precise, it was fixed to the sealing tube fixing member 61). As a result, when the lead wires 33a, 33b, and 33c need to be replaced, the six lead wires 33a, 33b, and 33c of the gas sensor corresponding to the broken lead wires can be pulled out. For this reason, it is not necessary to replace the lead wires 33a, 33b, and 33c of other gas sensors that do not require replacement, and only the six lead wires 33a, 33b, and 33c including the broken lead wires are replaced. Good. In addition, since the six lead wires 33a, 33b, and 33c are integrally bundled by the sealing tube 81, they can be easily inserted and removed. Further, the airtightness between the flange member 82 and the sealing tube fixing member 61 is easily ensured by the O-ring 86 attached to the step portion 85 of the flange member 82 fixed to the sealing tube fixing member 61. That is, only by inserting the sealing tube 81 into the sealing tube insertion hole 66 of the sealing tube fixing member 61 and inserting the bolt 87 from the outside of the flange member 82 and tightening, the sealing tube fixing member of the sealing tube 81 is secured. The fixing to 61 and the securing of the airtightness between the sealing tube 81 (more precisely, the flange member 82) and the sealing tube fixing member 61 are completed. Therefore, the replacement work of the gas sensor and the lead wires 33a, 33b, and 33c is simplified.

<Effect of embodiment>
Therefore, according to the present embodiment, the following effects can be obtained.
(1) A plurality of lead wires 33a, 33b, and 33c drawn from a single gas sensor are set as one unit, inserted into a sealing tube 81 provided corresponding to each unit, and the sealing tube 81 is connected to a terminal. Removably fixed to the side wall of the box 12. For this reason, the lead wires 33a, 33b, and 33c can be exchanged for each gas sensor. That is, when the gas sensor is replaced, the lead wires 33a, 33b, and 33c of the gas sensor to be replaced may be broken. In this case, the lead wires 33a, 33b, and 33c need to be replaced. At that time, it is not necessary to replace all the lead wires 33a, 33b, and 33c of each gas sensor, and the one unit lead wire 33a including the lead wire that is inserted through the sealing tube 81 at once and that has been bent or the like is generated. , 33b and 33c need only be replaced. Even during the replacement, the lead wires 33a, 33b, and 33c are bundled by being inserted into the sealing tube 81 for each unit, so that the attaching / detaching operation to the side wall of the terminal box 12 is also easy. Therefore, when the lead wire is broken, the replacement work of the lead wires 33a, 33b, 33c can be simplified.

  (2) A flange member 82 protrudes from the outer peripheral surface of the sealing tube 81, and the sealing tube 81 is detachably fixed to the side wall of the terminal box 12 via the flange member 82. For this reason, the sealing tube 81 can be easily fixed to the side wall of the terminal box 12 by using the flange member 82. Further, it is not necessary to apply and cure silicon, and the hermetic structure can be reconstructed, so that the silicon curing time is eliminated and the hermetic inspection is facilitated. For this reason, the gas sensor replacement work time can be greatly reduced.

  (3) A sealing tube fixing member 61 is fixed to the inner surface of the side wall of the terminal box 12, and the sealing tube 81 is detachably fixed to the sealing tube fixing member 61 via its flange member 82. I did it. For this reason, even if the side wall of the terminal box 12 is distorted for some reason, the distortion or the like does not affect the fixing of the sealing tube 81 through the sealing tube fixing member 61. For this reason, the fixing of the sealing tube 81 can be further stabilized.

  (4) The flange member 82 is formed in a regular triangular plate shape, and is provided so that the sealing tube 81 passes through the center thereof. And each flange member 82 was each arrange | positioned so that the mutually opposing one side may make a parallel in a pair of flange member 82 adjacent in the column direction. For this reason, each flange member 82 can be assembled to such an extent that each sealing pipe 81 can be inserted into the main pipe 13.

  As the shape of the flange member 82, various shapes such as a circle, a square, a rectangle and the like can be considered in addition to the regular triangle in the present embodiment. However, when the flange members 82 have other shapes, even if the sealing tubes 81 are inserted into the main tube 13, the flange members 82 interfere with each other and are difficult to attach. For example, when the flange member 82 is formed in a circular plate shape, for example, when the sealing tube 81 having the same outer diameter is made to penetrate the center of the flange member 82, the circular center and the circle from the center are circled. The distance from the center of the equilateral triangle to the one side is smaller than the distance from the center of the equilateral triangle (that is, the radius of the circle) to the center of the equilateral triangle and the distance from the center to one side of the equilateral triangle. The same applies to the case where the flange member 82 has a shape such as a square and a rectangle. Therefore, in order to arrange the flange members 82 closer to each other, it is desirable to form the flange members 82 in a regular triangle shape as in the present embodiment.

  (5) The one-unit lead wires 33a, 33b, and 33c are arranged along the inner peripheral surface of the sealing tube 81 at regular intervals, and the sealing tube 81 is kept in a state where the arrangement is maintained. I pulled out from both ends. For this reason, each lead wire 33a, 33b, 33c is pulled out from both ends of the sealing tube 81 in the aligned state while maintaining the regular circumferential arrangement state described above. For this reason, the entanglement of the lead wires 33a, 33b, 33c in the vicinity of both ends of the sealing tube 81 is suppressed.

  (6) The main pipe lid 24 of the main pipe 13 is formed with a through hole 24a that communicates the inside of the main pipe 13 and the flue, and a J-shaped bent pipe 37 is formed in the through hole 24a from the inner surface side of the main pipe lid 24. Connected. The bent tube 37 is a tube body that is open at both ends. One end of the bent tube 37 is connected from the inner surface side of the main tube lid 24, while the other end side is bent in a direction intersecting the tube axis of the main tube 13. It was made to open in the main pipe 13 in the state toward the side.

  The gas sensor element has a ratio between the product of the pressure in the flue and the oxygen concentration of the gas to be measured in the flue and the product of the pressure in the main pipe 13 and the oxygen concentration of the reference gas supplied into the main pipe 13. Based on the output voltage. Here, since the inside of the flue and the inside of the main pipe 13 communicate with each other through the through hole 24a (bent pipe 37), the pressure in the flue and the pressure in the main pipe 13 are the same. Therefore, the pressure in the flue and the pressure in the main pipe 13 can be ignored, and the oxygen concentration in the gas to be measured can be obtained from the voltage output from the gas sensor element and the oxygen concentration in the reference gas.

  In addition, the gas to be measured flowing in the flue often contains a large amount of foreign matter such as dust, and this foreign matter may enter the main pipe 13 through the through hole 24 a of the main pipe lid 24. However, in the present embodiment, the bent tube 37 bent in the direction intersecting the tube axis of the main tube 13 is connected to the through hole 24a from the inner surface side of the main tube lid 24. Entry to is suppressed. That is, since the bending of the bent tube 37 becomes a pipe resistance, the foreign matter that has entered the bent tube 37 through the through hole 24 a is less likely to pass through the bent tube 37.

  (7) A terminal block 74 is provided in the terminal box 12, and lead wires 33a, 33b and 33c introduced into the terminal box 12 are connected to the terminal block 74. For this reason, the connection with the external control device is facilitated through the terminal block 74.

  (8) A terminal box fixing member 27 is provided at the proximal end portion of the main pipe 13, and the terminal box fixing member 27 tightens the bolt 50 inserted from the inner surface side of the side wall of the terminal box 12 to tighten the terminal box 12. It fixed to the outer surface of the side wall. For this reason, since the head of the bolt 50 is not exposed to the outside of the terminal box 12, the appearance of the gas analyzer 11 is improved.

  (9) The sealing tube fixing member 61 is inserted into the terminal box 12 through the bolt 63 so as to penetrate the side wall of the terminal box 12 and tighten the bolt 63 to the terminal box fixing member 27. The inner surface of the side wall of the box 12 is fixed. For this reason, unlike the case where the bolts 63 for fixing the sealing tube fixing member 61 are tightened from the outside of the terminal box 12, the heads of the bolts 63 are not exposed to the outside of the terminal box 12. Therefore, the appearance of the gas analyzer 11 can be further improved.

  (10) A flange portion 15 is provided on the outer peripheral surface of the main pipe 13, and the main pipe 13 is fixed to the flue wall W constituting the flue via the flange portion 15. For this reason, the main pipe 13 can be easily fixed to the flue wall W via the flange portion 15 provided on the outer peripheral surface thereof. Further, a reference gas inlet 29 is provided between the flange portion 15 and the terminal box fixing member 27 on the peripheral wall of the main pipe 13. For this reason, for example, the formation becomes easier as compared with the case where the reference gas introduction port 29 is formed on the outer peripheral surface of the flange portion 15.

  (11) The reference gas introduction port 29 is provided so as to protrude from the outer peripheral surface of the main pipe 13. For this reason, when the reference gas inlet 29 and the reference gas supply source are connected by a tube such as a flexible tube, the tube can be easily connected to the reference gas inlet 29.

  (12) The terminal box fixing member 27 is fixed to the outer surface of the terminal box 12 by tightening a plurality of bolts 50 inserted from the inside of the terminal box 12. For this reason, unlike the case where each bolt 50 is tightened from the outside of the terminal box 12, each bolt 50 is not exposed to the outside. Therefore, the appearance of the gas analyzer 11 is improved.

  (13) An opening 41a for maintenance is formed on the side of the terminal box 12, and a cover 42 for closing the opening 41a is provided. Further, a flange portion 44 is formed on the side portion of the terminal box 12, and a packing 43 is disposed between the flange portion 44 and the cover 42. The cover 42 is provided with a covering wall 42 b that covers the outer peripheral edge of the packing 43 exposed between the flange portion 44 and the cover 42. For this reason, it is suppressed that the light from the outside is irradiated to packing 43 (especially the outer periphery). As a result, deterioration of the packing 43 due to light is suppressed, and the product life of the packing is also ensured. When the gas analyzer 11 is installed outdoors, it is particularly effective by suppressing the irradiation of the sunlight to the packing 43.

  (14) The four sealing tubes 81 are inserted and supported with respect to the sealing tube fixing member 61 fixed to the inner surface of the side wall of the terminal box 12. For this reason, when assembling the gas analyzer 11, four sealing tubes 81 are attached to the sealing tube fixing member 61 in advance, and the sealing tube fixing member 61 is attached to the terminal box 12. Compared with the case where the pipes 81 are attached to the terminal box 12 one by one, the mounting work of the sealing pipe 81 is simplified. As a result, the assembly work efficiency of the gas analyzer 11 can be improved.

  (15) The main pipe 13 is attached so that each gas sensor holding portion 21 (filter cover 22) faces the downstream direction with respect to the flow of the gas to be measured. For this reason, even when the gas to be measured contains a large amount of foreign matter such as dust, the foreign matter can be prevented from hitting the filter 32 and clogging of the filter 32 can be suppressed.

<Another embodiment>
In addition, you may implement each said embodiment as follows.
In the present embodiment, the covered cylindrical filter cover 22 is screwed into the outer end portion of the gas sensor holding portion 21 so as to cover the filter 32 on the outer end surface of the gas sensor holding portion 21. This is to prevent the foreign matter from directly hitting the filter 32 and to prevent the filter 32 from being clogged when the measurement gas contains a large amount of foreign matter such as dust. However, when the gas to be measured has a small amount of foreign matter such as dust, an annular filter cover 91 as shown in FIG. 5B may be used. By doing so, the inflow amount of the gas to be measured from the filter 32 is ensured by opening the upper wall, and the sensitivity of the gas sensor element is improved.

  In the present embodiment, the present invention is embodied in a so-called four-point gas analyzer 11 having four gas sensor holding portions 21. However, the present invention is applied to two-point and three-point gas analyzers. Also good. Two gas sensor holders 21 are prepared for two points, and three gas sensor holders 21 are prepared for three points.

In the present embodiment, the bent tube 37 is J-shaped, but any portion such as a serpentine shape, S-shape, L-shape, and U-shape may be used as long as a portion of the tube is bent. You may make it do.
In the present embodiment, the four flange members 82 are arranged so that the sides facing each other in the pair of flange members 82 and 82 adjacent in the column direction are parallel to each other. . That is, the four flange members 82 are respectively arranged so that one side of the pair of flange members 82 and 82 adjacent in the row direction is parallel to each other.

<Another technical idea>
Next, the technical idea that can be grasped from the embodiment and another embodiment will be described below.

  (A) A sealing tube fixing member is fixed to the inner surface of the side wall of the main body box, and the sealing tube is inserted into the sealing tube fixing member and attached to and detached from the sealing tube fixing member through its own flange member. The gas analyzer according to any one of claims 1 to 4, wherein the gas analyzer is fixed in a possible manner.

  (B) The main body box fixing member is fixed to the outer surface of the side wall of the main body box by tightening a bolt inserted from the inner surface side of the side wall of the main body box. The gas analyzer according to any one of items a).

  (C) In the gas analyzer according to (b), the sealing tube fixing member is inserted through a bolt from the inside of the main body box and through the side wall of the main body box, and the bolt is inserted into the main body. A gas analyzer that is fixed to the inner surface of the side wall of the main body box by being fastened to a box fixing member.

(D) The gas analyzer according to claim 4, wherein the reference gas introduction port projects from the outer peripheral surface of the main pipe.
(E) A side opening of the main body box is formed with a maintenance opening and a cover 42 for closing the opening is detachably provided, and a packing is provided between the opening periphery of the main body box and the cover. The gas analyzer according to any one of claims 1 to 4 and (a) to (c), wherein a covering portion that is disposed and covers an outer peripheral edge of the packing is provided on the cover.

The front view which shows the state attached to the flue wall of the gas analyzer in this embodiment. The principal part disassembled perspective view of a gas analyzer similarly. The principal part disassembled perspective view of a gas analyzer similarly. The principal part front sectional drawing of the main pipe which similarly shows the attachment state of a gas sensor. (A) is an exploded perspective view which similarly shows the front-end | tip part of a main pipe, (b) is a perspective view of the filter cover in another embodiment. The principal part sectional drawing of the terminal box which similarly shows the attachment state of a cover. (A) is a side view of the main pipe lid similarly attached to the front-end | tip of a main pipe, (b) is a front sectional view of a main pipe lid similarly. The front view of a sealing pipe fixing member similarly. (A) is the principal part front sectional view of the main pipe which similarly shows the attachment state of a sealing pipe, (b) is a cross-sectional view of the sealing pipe which similarly shows the arrangement state of a lead wire. (A) is a front sectional view of the flange member, (b) is a left side view of the flange member, and (c) is a right side view of the flange member. Front sectional view of a conventional gas analyzer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Gas analyzer, 12 ... Terminal box (main body box), 13 ... Main pipe, 15 ... Flange part,
21 ... Gas sensor, 27 ... Terminal box fixing member (main body box fixing member), 29 ... Reference gas inlet,
33a, 33b, 33c ... lead wire, 24 ... main tube lid (tip wall of main tube), 24a ... through hole, 37 ... bent tube (tube), 42b ... covered wall, 50, 63 ... bolt, 61 ... sealing tube Fixing member, 74 ... terminal block, 81 ... sealing tube, 82 ... flange member, W ... flue wall.

Claims (4)

A main body box, and a main pipe extending from the main body box and inserted into the flue,
A plurality of gas sensors that are detachably attached to the peripheral wall of the main pipe and detect predetermined components contained in the gas to be measured flowing in the flue;
A plurality of lead wires each led out from each of the gas sensors,
In the gas analyzer, the lead wires are introduced into the main body box through the main pipes, and the gas to be measured is analyzed based on outputs from the gas sensors taken out from the lead wires.
A plurality of lead wires drawn out from a single gas sensor are regarded as one unit, and a plurality of units of lead wires corresponding to the respective gas sensors are inserted into sealing tubes provided corresponding to the respective gas sensors. Is a gas analyzer that is detachably fixed to the side wall of the main body box. An outer peripheral surface of the sealing tube is provided with a flange member having a plate shape of an equilateral triangle so that the sealing tube passes through the center thereof,
The flange members of each sealing tube are arranged so that one side of a pair of adjacent flange members is parallel to each other,
The gas analyzer according to claim 1, wherein a sealing tube is detachably fixed to the side wall of the main body box via the flange member. A through hole is formed in the tip wall of the main pipe to communicate the main pipe and the flue,
One end of a tube body that is open at both ends is connected to the through-hole from the inner surface side of the tip wall, and the other end side is also opened in the main tube while being bent in a direction intersecting the tube axis of the main tube. The gas analyzer according to claim 1 or claim 2. A main body box fixing member for fixing the main body box is provided at a base end portion of the main pipe, and a flange for fixing the main pipe to the flue wall of the flue is provided at a tip side of the main body box fixing member. Set up a section,
The gas analyzer according to any one of claims 1 to 3, wherein an inlet for a reference gas is provided between the flange portion and the main body box fixing member in the main pipe.

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