JP4327112B2 - Gas measuring device - Google Patents

Description

  The present invention relates to a gas measuring device that collects flue gas such as boilers and incinerators and measures the concentration of dust contained in the flue gas.

  Conventionally, for the purpose of reducing air pollution, etc., the dust concentration such as dust contained in flue gas (hereinafter referred to as “measurement gas”) discharged from boilers and incinerators is measured and measured. Based on the values, operation management (for example, combustion control) of the boiler and the incinerator is performed. As a gas measuring device for measuring the concentration of dust such as dust contained in the gas to be measured, two types of light transmission method and light scattering method are mainly known. In the light transmission method, the gas to be measured is irradiated with light, the amount of transmitted light is measured, and the dust concentration is obtained based on the measured value. In the light scattering method, the gas to be measured is irradiated with light, the amount of scattering or reflection of the light is measured, and the dust concentration is obtained based on the measured value.

  In addition, for the same purpose as described above, a predetermined component concentration (for example, oxygen concentration) of flue gas is also measured. As such a gas measuring device, for example, a configuration as shown in Patent Document 1 is used. Are known. That is, as shown in FIG. 5, the gas measuring device 100 includes a tube body 101 for taking in the gas A to be measured flowing in the flue. The pipe body 101 includes an introduction pipe 102 inserted into a flue, a discharge pipe 103, and a U-shaped main flow path 104 that connects both pipes on the outer end side. An ejector 105 is connected to a portion corresponding to the outer end portion of the tube 103. Further, both ends of the branch pipe 106 are connected to the main flow path 104 on the introduction pipe 102 connection side, and an oxygen concentration detector 107 is provided in the middle of the branch pipe 106. Further, two purge pipes 108 a and 108 b are connected to the main flow path 104, respectively, so that one purge pipe 108 a is close to the introduction pipe 102 and the other purge pipe 108 b is close to the discharge pipe 103. Are arranged as follows.

  Now, when the ejector air B (air) is supplied from the ejector 105 to the main flow path 104, the measured gas A in the flue is introduced into the introduction pipe 102, and the introduced measured gas A passes through the main flow path 104. And discharged into the flue through the discharge pipe 103. Here, a part of the measurement gas A introduced from the introduction pipe 102 is diverted to the diversion pipe 106 and returns to the main flow path 104 through the oxygen concentration detector 107. An oxygen concentration detector 107 detects the oxygen concentration of the gas to be measured that has flowed to the branch pipe 106.

As the gas measuring apparatus 100 is used, soot contained in the measurement gas gradually accumulates in the introduction pipe 102, the discharge pipe 103, and the main flow path 104. For this reason, purge air C is appropriately supplied from the purge pipes 108a and 108b into the main flow path 104, whereby dust in the main flow path 104 is removed. The purge pipe C supplied from one purge pipe 108a cleans the introduction pipe 102 side, and the purge air C supplied from the other purge pipe 108b cleans the discharge pipe 103 side.
Japanese Utility Model Publication No. 7-26683

  In the conventional gas measuring device, the purge tank 110 is provided in the middle of the pipe 109 in order to suppress the pressure drop of the purge air C caused by the pressure loss in the pipe 109 from the compression pump (not shown) to both the purge pipes 108a and 108b. I was trying to provide it. That is, the purge air C generated by the compression pump is temporarily accumulated in the purge tank 110 to increase the pressure in the purge tank 110. Then, in a state where the pressure is increased, the valve body 111 provided on the downstream side of the purge tank 110 in the pipe 109 is opened, so that the high-pressure purge air C is sent to both the purge pipes 108a and 108b. With this configuration, it is not necessary to consider the pressure loss due to the pipe 109 from the compression pump to the purge tank 110, and the pressure of the purge air C in both the purge pipes 108a and 108b is ensured. Incidentally, when the purge tank 110 is not provided, the pressure in the purge pipes 108a and 108b decreases due to pressure loss due to the pipe 109 from the compression pump to the purge pipes 108a and 108b, and the pressure in the main flow path 104 is reduced. Dust may not be removed sufficiently.

  However, in the gas measuring apparatus as described above, the length of the introduction pipe 102 is set according to the size of the flue (flue diameter). For this reason, the larger the flue, the longer the introduction pipe 102 needs to be lengthened. In such a case, the pressure of the purge air tends to be particularly insufficient. As described above, once the purge air is temporarily stored in the purge tank 110, the pressure in the purge pipes 108a and 108b can be secured. There is also concern about the lack of pressure. This is because the air pressure gradually decreases due to the pressure loss caused by the main flow path 104 and the introduction pipe 102 until the purge air passes through the introduction pipe 102 from both purge pipes 108a and 108b. Accordingly, there has been a demand for a new configuration or further improvement for more effectively removing the dust in the tube body 101.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a gas measuring device that can effectively remove dust in the tube.

According to the first aspect of the present invention, the gas to be measured is introduced from the gas inlet of the tubular body inserted into the flue, the introduced gas to be measured is led out of the flue, and a predetermined component concentration is measured. In the gas measuring apparatus that is led out from the gas outlet of the pipe into the flue, the pipe is provided with an inlet pipe having the gas inlet at one end and the gas outlet at one end. and an outlet pipe, and a connection pipe for connecting the other end portion exposed to smoke outside Hokkaido in their both tube opposite to the previous SL both openings, the connecting pipe, inner surfaces of the outlet pipe of the inlet pipe so as to form a U-shape by curved guide portion smoothly continuous bets, the other end of the connection pipe opposite to the gas outlet of the outlet tube in the tube body, the gas guide It provided a first purge air supply port for supplying purge air towards the outlet and the guide portion Together, the gas inlet close at the site exposed to the smoke of the inlet pipe outside Hokkaido is provided with a second purge air supply port for supplying purge air obliquely towards the gas inlet, from the first purge air supply port A part of the supplied purge air is guided by the guide portion of the connecting pipe and is divided into the inlet pipe, and from the first purge air supply port by negative pressure suction by the purge air supplied from the second purge air supply port. The gist is that the supplied purge air flows into the inlet pipe via the connecting pipe .

According to a second aspect of the invention, the gas measuring device according to claim 1, the gas outlet of the outlet pipe in the pipe body detachably adapter to the other end of the connection pipe opposite The gist is that the adapter is provided with an ejector air supply port for supplying ejector air toward the gas outlet port of the outlet pipe and the first purge air supply port.

According to a third aspect of the present invention, in the gas measuring device according to the second aspect , the first purge air supply port is located closer to the inlet pipe than the pipe axis of the outlet pipe in a state where the adapter is attached to the connecting pipe. The gist is that it is provided so as to be positioned.

According to a fourth aspect of the invention, the gas measuring device according to claim 2 or claim 3, arranged so as to protrude the nozzle member into the connecting pipe to the inner surface of the adapter, through the nozzle member The gist of the invention is that the ejector air from the ejector air supply port is supplied into the outlet pipe, and the nozzle member is provided so that its tip is located closer to the gas outlet port than the tube axis of the connecting pipe.

(Function)
According to the first aspect of the present invention, when the purge air is supplied from the first purge air supply port provided at the end of the connecting pipe opposite to the gas outlet of the outlet pipe in the pipe body, The pipe is purified by purge air flowing toward the gas outlet. Meanwhile, the purge air supplied from the second purge air supply port is supplied obliquely toward the gas inlet relative to the inlet pipe. Further, a negative pressure is generated by the supply of the purge air (so-called ejector effect), and a part of the purge air supplied from the first purge air supply port is sucked through the connecting pipe and flows into the outer end side of the inlet pipe. . The inlet pipe is purified by the purge air from the first purge air supply port that has flowed through the purge air and the connecting pipe from the second purge air supply port. Thus, by utilizing the ejector effect, dust in the pipe can be removed uniformly and effectively. In addition, since purge air is supplied from the gas inlet near the portion exposed outside the flue of the inlet pipe, the length of the inlet pipe can be increased.

Then, by forming a curved guide portion smoothly continuous with the inner surfaces of the outlet pipe of the inlet pipe to the inner surface of the consolidated tube, the purge air supplied from the first purge air supply port of the connecting tube, By being guided by the guide portion, the flow is more smoothly diverted to the outer end side of the inlet pipe. Further, the suction effect of the purge air into the inlet pipe by the ejector effect can be enhanced. Accordingly, the dust in the inlet pipe can be more effectively removed.

According to the invention described in claim 2 , negative pressure is generated by supplying ejector air from the end of the outlet pipe opposite to the gas outlet, and as a result, the gas to be measured in the flue is introduced into the gas It is introduced into the inlet pipe through the mouth. The introduced gas to be measured merges with the outlet pipe through the connecting pipe, and is led out into the flue together with the ejector air flowing toward the gas outlet. Further, in the present invention, since the ejector air supply port and the first purge air supply port are respectively provided in the adapter that is detachably attached to the outlet pipe, the ejector air supply port and the first purge air supply port are respectively connected to the pipe. Compared with the case where the body (exactly, the outlet pipe) is provided, the configuration of the pipe body can be simplified. Moreover, since the ejector air supply port and the first purge air supply port can be provided simply by mounting the adapter on the outlet pipe, the assembly of the pipe body is also improved.

According to the invention described in claim 3 , in addition to the operation of the invention described in claim 2 , in the state where the adapter is attached to the outlet pipe, the first purge air supply port is located closer to the inlet pipe than the pipe axis of the outlet pipe. Therefore, the purge air from the first purge air supply port is easily blown to the guide portion. For this reason, it is possible to efficiently ensure the purge air that is diverted to the inlet pipe.

According to the invention of claim 4 , in addition to the action of the invention of claim 2 or claim 3 , the tip of the nozzle member is located closer to the gas outlet than the tube axis of the connecting pipe. Inflow of ejector air from the nozzle member into the connecting pipe and the inlet pipe is suppressed. For this reason, the suction effect of the gas to be measured in the flue can be ensured.

  According to the present invention, dust in the pipe can be effectively removed.

  Hereinafter, the present invention is embodied in a light scattering type dust concentration meter that measures the concentration of soot contained in a gas to be measured such as exhaust gas that is attached to an exhaust pipe of a boiler or an incinerator and flows through a flue in the exhaust pipe. A simplified embodiment will be described with reference to FIGS. In the light scattering method, if the properties (shape distribution, color, composition, etc.) of dust particles such as dust are constant, the light scattering amount (light scattering intensity) when the dust particles are irradiated with light is the dust weight, that is, It utilizes a characteristic proportional to the dust concentration.

  As shown in FIG. 1, a cylindrical insertion port M protrudes from a flue wall W that is a tube wall of an exhaust pipe, and an annular flange portion Ma is formed on the outer peripheral edge of the distal end of the insertion port M. Has been. As shown in FIG. 3, a plurality of insertion holes Mb are formed in the flange portion Ma at predetermined intervals in the circumferential direction of the flange portion Ma. And the dust concentration meter 11 as a gas measuring apparatus in this invention is attached to the flue wall W using this flange part Ma.

  The dust concentration meter 11 includes a tube body 12 that takes in a gas to be measured that is inserted into the flue through the insertion port M and flows through the flue. The pipe 12 includes an inlet pipe 13 provided with a gas inlet 13a at one end, an outlet pipe 14 provided with a gas outlet 14a at one end, and the gas inlet 13a and outlet pipe of these inlet pipes 13. 14 is formed in a U-shape as a whole from the connecting pipe 15 that connects the other end portions opposite to the gas outlet port 14a. Further, the pipe body 12 includes a flange portion 16 provided so as to penetrate the inlet pipe 13 and the outlet pipe 14 respectively. A plurality of studs 17 are provided on the flange portion 16 so as to protrude from the side surface on the insertion side of the tubular body 12 and at predetermined intervals in the circumferential direction of the flange portion 16.

  The tube body 12 is inserted into the insertion port M from the distal end side where the gas introduction port 13a and the gas outlet port 14a are formed, and the implantation bolts 17 of the flange portion 16 are inserted into the insertion holes Mb of the flange portion Ma. The nuts 18 are respectively fastened to the studs 17 so as to be fixed to the flue wall W (more precisely, the flange portion Ma of the insertion port M). Further, a seal member 19 such as packing is interposed between the flange portion Ma of the insertion port M and the flange portion 16 of the tube body 12, and the seal member 19 allows the inside and outside of the flue, that is, both flange portions Ma, The airtightness between 16 is secured.

<Inlet pipe>
A measurement chamber 21 is provided in the middle of the outer end side of the inlet pipe 13, and a light emitting unit 22 and a light receiving unit 23 are provided so as to correspond to the measurement chamber 21. The light emitting unit 22 has a light source such as a photo LED (not shown) that emits infrared light, and light such as infrared light emitted from the light source is applied to the gas to be measured flowing through the measurement chamber 21. The light receiving unit 23 has a sensor such as a photodiode (not shown) that receives scattered light caused by dust such as dust in the gas to be measured, and the dust concentration of the gas to be measured is based on the amount of light received by the sensor. Desired. The light receiving unit 23 is provided so as to form a predetermined angle (for example, about 70 degrees) with respect to the optical axis of the light emitting unit 22 (more precisely, the light source).

  As shown in FIG. 3, a span rod insertion port 24 is formed at the end of the inlet pipe 13 opposite to the gas introduction port 13a, and the span rod insertion port 24 is attached with a cap 25. It is blocked. At the time of span calibration, the cap 25 is removed, and a span bar (not shown) is inserted into the span bar insertion port 24.

  In the inlet pipe 13, a purge air supply port 31 is provided on the pipe wall near the gas inlet 13 a between the flange portion 16 and the measurement chamber 21. As shown in FIG. 4, the purge air supply port 31 is formed obliquely toward the gas introduction port 13a. The angle θ formed between the central axis of the purge air supply port 31 and the tube axis of the inlet pipe 13 is preferably as small as possible from the viewpoint of obtaining the ejector effect described later, and is set to 45 degrees in this embodiment.

  On the outer peripheral surface of the inlet pipe 13, a cylindrical connector member 32 having both ends opened from the opening edge of the purge air supply port 31, and the pipe axis of the connector member 32 is orthogonal to the pipe axis of the inlet pipe 13. is doing. A purge air supply source 33 such as a compressor is connected to the connector member 32, and the purge air generated in the purge air supply source 33 is supplied obliquely toward the gas inlet 13a via the connector member 32 and the purge air supply port 31. .

  A check valve (not shown) is provided on the supply path from the purge air supply source 33 to the purge air supply port 31, and only air flow from the purge air supply source 33 to the purge air supply port 31 is allowed. That is, the backflow of the gas to be measured introduced from the gas introduction port 13a from the purge air supply port 31 to the purge air supply source 33 is suppressed.

  As shown in FIG. 3, a valve mechanism 34 is provided between the flange portion 16 (more precisely, the purge air supply port 31) and the measurement chamber 21 in the inlet pipe 13. The valve mechanism 34 is opened and closed by operating a handle 34a shown in FIG. 2, whereby the inlet pipe 13 is blocked or communicated.

<Exit pipe>
An adapter mounting port 41 is formed at the end of the outlet pipe 14 opposite to the gas outlet port 14a, and a rectangular parallelepiped adapter 42 can be attached to and detached from the adapter mounting port 41 as shown in FIG. It is attached to. A cylindrical nozzle member 43 protrudes from the inner surface of the adapter 42, and an ejector air supply port 44 is formed on the lower surface, and an inverted L-shaped purge air supply port 46 is formed on the upper surface. .

  The nozzle member 43 is arranged so that the central axis thereof substantially coincides with the tube axis of the outlet pipe 14, and the tip of the nozzle member 43 is located in a portion corresponding to the connecting pipe 15 in the outlet pipe 14. Thus, the protrusion height from the inner surface of the adapter 42 of the nozzle member 43 is set. Specifically, the nozzle member 43 is provided so that the tip thereof is positioned on the gas outlet 14 a side with respect to the tube axis of the connecting tube 15.

  The ejector air supply port 44 is formed in the lower surface of the adapter 42 so as to communicate with the inside of the nozzle member 43. An ejector air supply source 45 such as a compressor is connected to the ejector air supply port 44 via a pipe (not shown), and the ejector air generated by the ejector air supply source 45 is directed to the gas outlet 14 a via the ejector air supply port 44. Supplied straight.

  The purge air supply port 46 is formed with an opening on the upper surface of the adapter 42 so as to communicate with the tube body 12. The purge air outlet of the purge air supply port 46 is arranged on the inner surface of the adapter 42 closer to the inlet pipe 13 than the nozzle member 43. A purge air supply source 33 is connected to the purge air supply port 46 via a pipe (not shown), and the purge air generated in the purge air supply source 33 is supplied straight to the gas outlet port 14a via the purge air supply port 46. Is done.

  As shown in FIG. 3, a valve mechanism 47 is provided in the middle of the outlet pipe 14 so as to correspond to the valve mechanism 34, and the valve mechanism 47 operates a handle 47a shown in FIG. Open and close by. As a result, the outlet pipe 14 is blocked or communicated.

  On the inner surface of the connecting pipe 15, a curved guide portion 15 a is formed that smoothly and smoothly continues the inner surfaces of the inlet pipe 13 and the outlet pipe 14. The guide portion 15a is blown with purge air supplied from the purge air supply port 46 of the adapter 42 and guides a part thereof to the inlet pipe 13 side.

<Operation during measurement>
Next, the operation at the time of dust concentration measurement by the dust concentration meter configured as described above will be described.
When measuring the dust concentration of the gas to be measured flowing in the flue, the ejector air from the ejector air supply source 45 is supplied into the pipe body 12 through the nozzle member 43 with the valve mechanisms 34 and 47 opened. . The ejector air ejected from the nozzle member 43 flows from the outer end side of the outlet pipe 14 toward the gas outlet port 14a. Then, the flow pressure of the ejector air flowing from the outer end side to the inner end side in the outlet pipe 14 becomes smaller than the flow pressure of the gas to be measured flowing in the flue. That is, due to the negative pressure on the outlet pipe 14 side (so-called ejector effect), the gas to be measured flowing in the flue is taken into the inlet pipe 13 from the gas inlet 13a. The taken gas to be measured passes through the connecting pipe 15 and the outlet pipe 14 and returns to the flue from the gas outlet 14a. On the other hand, the gas to be measured taken into the inlet tube 13 is irradiated with light such as infrared rays from the light source when passing through the measurement chamber 21, and the amount of scattering is detected by the sensor of the light receiving unit 23. A control device (not shown) obtains the dust concentration based on the obtained sensor output. As described above, the dust concentration of the flue gas flowing in the flue is continuously measured.

<Action during purging>
Next, the operation of the dust concentration meter at the time of purging in the tube body 12 will be described.
The purge of the tube body 12 is performed with the supply of ejector air stopped. That is, when the purge air supply source 33 is driven, the purge air (compressed air) generated by the purge air supply source 33 is supplied to the purge air supply port 46 and the purge air supply port 31 of the adapter 42, respectively.

  Then, most of the purge air supplied into the outlet pipe 14 via the purge air supply port 46 of the adapter 42 flows straight toward the gas outlet 14a along the tube axis of the outlet pipe 14, and the gas outlet 14a. To the flue. As purge air passes through the outlet pipe 14, dust such as soot adhering to the inner surface of the outlet pipe 14 is blown off and discharged into the flue together with the purge air.

  A part of the purge air supplied from the purge air supply port 46 of the adapter 42 is guided by the guide portion 15 a of the connecting pipe 15 and is divided into the inlet pipe 13. Then, the purge air that has flowed through the connecting pipe 15 passes through the connecting pipe 15, whereby dust adhering to the inner surface of the connecting pipe 15 is blown off. The purge air that has flowed into the outer end side of the inlet pipe 13 flows toward the gas introduction port 13a, merges with the purge air supplied from the purge air supply port 31, and is discharged from the gas introduction port 13a into the flue. Thereby, the dust in the section from the outer end side of the inlet pipe 13 to the vicinity of the purge air supply port 31 is removed.

  On the other hand, the purge air supplied from the purge air supply port 31 is supplied obliquely into the inlet pipe 13 toward the gas inlet 13a, and is discharged from the gas inlet 13a into the flue. In this way, by supplying purge air from a part as close as possible to the gas inlet 13a in the part exposed outside the flue of the inlet pipe 13, the gas inlet 13a of the inlet pipe 13 is maintained with the pressure of the purge air kept as much as possible. To flow. For this reason, the removal of the dust in the site | part inserted in the flue of the inlet pipe 13 is performed effectively.

  For example, when purge air is supplied from the outer end side of the inlet pipe 13 (on the side of the span rod insertion port 24), the purge air also reaches the point where the inlet pipe 13 is inserted into the flue. Pressure loss occurs and the pressure of the purge air is reduced. Further, pressure loss also occurs when flowing through the portion of the inlet pipe 13 that is inserted into the flue, so the pressure of the purge air decreases as it flows to the gas inlet 13a. Here, the larger the flue is, the longer the inlet pipe 13 (more precisely, the insertion portion into the flue) needs to be longer. The longer the insertion portion of the inlet pipe 13 into the flue, the more the pressure drop described above. The problem becomes significant. In such a case, the arrangement of the purge air supply port 31 of the present embodiment is particularly effective, and the purge failure due to the insufficient pressure of the purge air is suppressed.

  Further, the purge air is obliquely supplied toward the gas inlet 13 a of the inlet pipe 13, thereby generating a negative pressure in the measurement chamber 21. As a result, the purge air is supplied from the purge air supply port 46 of the adapter 42 into the outlet pipe 14. The purge air is positively sucked into the inlet pipe 13. That is, the so-called ejector effect promotes the splitting of the purge air supplied from the purge air supply port 46 into the inlet pipe 13 and the flow velocity of the purge air flowing through the connecting pipe 15 and the inlet pipe 13 toward the gas inlet 13a. Is increased. Here, the effect of reducing the pipe resistance by the guide portion 15a formed in a curved surface shape also enhances the suction effect of the purge air into the inlet pipe 13 by the ejector effect. For this reason, the removal of the dust of the area from the outer end side of the connection pipe 15 and the inlet pipe 13 to the purge air supply port 31 vicinity is also performed effectively. As described above, the dust is uniformly and effectively removed inside the tube body 12.

<Effect of embodiment>
Therefore, according to the present embodiment, the following effects can be obtained.
(1) A purge air supply port 46 for supplying purge air toward the gas outlet 14a is provided at the end of the outlet pipe 14 opposite to the gas outlet 14a. Further, a purge air supply port 31 for supplying purge air obliquely toward the gas introduction port 13a is provided near the gas introduction port 13a at a portion exposed outside the flue of the inlet pipe 13. Therefore, when purge air is supplied from the purge air supply port 46, the outlet pipe 14 removes (purifies) dust accumulated by the purge air flowing toward the gas outlet port 14a. On the other hand, the purge air supplied from the purge air supply port 31 is supplied obliquely to the inlet pipe 13 toward the gas introduction port 13a. Further, due to the ejector effect of the purge air, a part of the purge air supplied from the purge air supply port 46 is sucked through the connecting pipe 15 and flows into the outer end side of the inlet pipe 13. The inlet pipe 13 removes (purifies) dust accumulated by the purge air from the purge air supply port 31 and the purge air flowing in via the connecting pipe 15. Thus, by utilizing the ejector effect, the dust in the tube body 12 can be uniformly and effectively removed.

(2) Further, since purge air is supplied from the vicinity of the gas inlet 13a at a portion of the inlet pipe 13 exposed outside the flue, the length of the inlet pipe 13 can be increased.
(3) On the inner surface of the connecting pipe 15, a curved guide portion 15 a that smoothly continues the inner surface of the inlet pipe 13 and the inner surface of the outlet pipe 14 is formed. For this reason, the purge air supplied from the purge air supply port 46 of the outlet pipe 14 is guided by the guide portion 15 a and smoothly flows to the outer end side of the inlet pipe 13. Further, since the flow of purge air from the connection pipe 15 to the inlet pipe 13 becomes smooth, the suction effect of the purge air into the inlet pipe 13 by the ejector effect is enhanced. Therefore, the dust in the inlet pipe 13 can be removed more effectively.

  (4) The adapter 42 is detachably provided at the end of the outlet pipe 14 opposite to the gas outlet 14a. The adapter 42 is provided with an ejector air supply port 44 and a purge air supply port 46, respectively. Therefore, the configuration of the tube body 12 can be simplified as compared with the case where the ejector air supply port 44 and the purge air supply port 46 are provided in the tube body 12 (more precisely, the outlet tube 14). In addition, since the ejector air supply port 44 and the purge air supply port 46 can be provided simply by mounting the adapter 42 in the adapter mounting port 41, the assembling property of the tube body 12 is also improved.

  (5) In the state where the adapter 42 is mounted in the adapter mounting port 41, the purge air supply port 46 is provided so as to be positioned closer to the inlet tube 13 than the tube axis of the outlet tube 14. For this reason, the purge air from the purge air supply port 46 is easily blown to the guide portion 15a, and the purge air that is diverted to the inlet pipe 13 can be efficiently secured.

  (6) The nozzle member 43 is provided on the inner surface of the adapter 42 so as to protrude into the outlet pipe 14, and the ejector air from the ejector air supply port 44 is supplied into the outlet pipe 14 through the nozzle member 43. The nozzle member 43 is provided so that the tip thereof is positioned closer to the gas outlet 14 a than the tube axis of the connecting tube 15. For this reason, the inflow of the ejector air from the nozzle member 43 to the connection pipe 15 and the inlet pipe 13 is suppressed, and the suction effect of the gas to be measured in the flue can be ensured.

<Another embodiment>
In addition, you may implement each said embodiment as follows.
In the present embodiment, the connecting pipe 15 is provided so that its pipe axis is perpendicular to the pipe axes of the inlet pipe 13 and the outlet pipe 14, but the pipe axis of the connecting pipe 15 is the inlet pipe 13 and the outlet pipe. You may make it incline and cross | intersect with respect to 14 pipe axes. For example, the connection site of the inlet pipe 13 of the connecting pipe 15 is shifted (tilted) toward the gas inlet 13a. In this way, the purge air from the purge air supply port 46 can be more easily divided into the connecting pipe 15.

  A purge tank (not shown) may be provided between the purge air supply source 33 and the purge air supply ports 31 and 46. That is, once the purge air generated by the purge air supply source 33 is temporarily accumulated in the purge tank, the pressure is increased, and the purge air in the purge tank whose pressure has been increased is supplied to the purge air supply ports 31 and 46. In this way, the dust in the tube body 12 can be removed more effectively.

In the present embodiment, the dust densitometer 11 is a light scattering method, but may be a light transmission method and a light reflection method.
-In this embodiment, although this invention was applied to the dust concentration meter 11, you may apply to the gas measuring apparatus which measures oxygen concentration, nitrogen oxide concentration, etc., for example. In this case, the light emitting unit 22 and the light receiving unit 23 are replaced with an oxygen sensor or the like, thereby measuring the gas to be measured in the measurement chamber 21.

  In the present embodiment, ejector air from the ejector air supply source 45 is supplied into the pipe body 12 through the nozzle member 43 when measuring the dust concentration, and the gas to be measured flowing in the flue is supplied from the gas inlet 13a to the inlet pipe 13. However, the following may be used. That is, when the flow rate of the gas to be measured flowing in the flue is fast and can be naturally taken into the inlet pipe 13 from the gas inlet 13a, the ejector air from the ejector air supply source 45 does not have to be supplied.

The schematic block diagram of the gas measurement apparatus of this embodiment. The schematic perspective view which shows the external appearance of the transmitter main body which comprises a gas measuring apparatus similarly. Similarly, a front sectional view of the transmitter body. FIG. 1 is a sectional view taken along line 1-1 in FIG. 3. The schematic block diagram of the conventional gas measuring apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Dust densitometer (gas measuring device), 12 ... Tube, 13 ... Inlet pipe,
13a ... Gas inlet, 14 ... Outlet pipe, 14a ... Gas outlet, 15 ... Connecting pipe,
15a ... guide part, 31 ... purge air supply port (second purge air supply port),
42 ... Adapter, 43 ... Nozzle member, 44 ... Ejector air supply port,
46: Purge air supply port (first purge air supply port).

Claims (4)

The gas to be measured is introduced from the gas inlet of the pipe inserted into the flue, the measured gas is introduced to the outside of the flue and the concentration of a predetermined component is measured, and the inside of the flue from the gas outlet of the pipe In the gas measuring device derived to
The tube has an inlet pipe in which the gas inlet is provided at one end, and an outlet pipe the gas outlet is provided at one end, smoke in their both tube opposite to the previous SL both openings outside Hokkaido A connecting pipe for connecting the other end portions exposed to
The connecting pipe is formed in a U shape by a curved guide portion that smoothly and continuously connects the inner surface of the inlet tube and the inner surface of the outlet tube,
With the gas outlet of the outlet pipe in the pipe body to the other end of the connection pipe opposite, provided the gas outlet and the first purge air supply port for supplying purge air toward the guide portion , wherein the gas inlet port near at the site exposed to smoke outside Hokkaido inlet pipe, providing the second purge air supply port for supplying purge air obliquely towards the gas inlet,
A part of the purge air supplied from the first purge air supply port is guided by the guide portion of the connecting pipe to be diverted into the inlet pipe, and by negative pressure suction by the purge air supplied from the second purge air supply port. A gas measuring apparatus in which purge air supplied from the first purge air supply port flows into the inlet pipe through the connecting pipe . In the gas measuring device according to claim 1,
An adapter is detachably provided at the other end of the connecting pipe opposite to the gas outlet of the outlet pipe in the pipe body, and ejector air is supplied to the adapter toward the gas outlet of the outlet pipe. A gas measuring apparatus provided with an ejector air supply port and the first purge air supply port . The gas measuring device according to claim 2,
A gas measuring apparatus , wherein the first purge air supply port is provided so as to be positioned closer to the inlet pipe than the pipe axis of the outlet pipe in a state where the adapter is attached to the connecting pipe . In the gas measuring device according to claim 2 or 3,
A nozzle member is provided on the inner surface of the adapter so as to protrude into the connecting pipe, and the ejector air from the ejector air supply port is supplied into the outlet pipe through the nozzle member,
A gas measuring device in which the nozzle member is provided so that a tip thereof is positioned closer to a gas outlet port than a tube axis of a connecting tube.

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