JP2012145341A - Method for determining packing leak from exhaust gas sensor installation section and program for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine a leak of exhaust gas to an outside through a packing portion when an exhaust gas sensor to detect a concentration of gas such as carbon dioxide contained in the exhaust gas from combustion equipment is attached on an exhaust gas passage through a packing.SOLUTION: The present invention is applied to a system where an exhaust gas measuring device 3 is attached on an exhaust gas passage 2 from combustion equipment 1. An exhaust gas sensor 8 to detect a concentration of carbon monoxide, carbon dioxide, oxygen or nitrogen oxide contained in exhaust gas is attached on the exhaust gas measuring device 3 through a packing 10. Using a characteristic of the exhaust gas sensor 8, a sensor where an output thereof is sensitive to a fluctuation in a flow rate of the exhaust gas, the gas sensor 8 determines a leak of the exhaust gas to an outside through a position of the packing 10 based on the output of the exhaust gas sensor 8 when the combustion equipment 1 is not in operation as well as the output of the exhaust gas sensor 8 when the combustion equipment 1 is performing pre-purge.

Description

  In the present invention, when an exhaust gas sensor that detects the concentration of carbon monoxide or the like contained in exhaust gas from a combustion device is attached via a packing, leakage of the exhaust gas from the packing portion to the outside is mainly determined. It relates to a method and a program.

  As disclosed in the following Patent Document 1, combustion equipment such as a boiler or a water heater is provided with various exhaust gas sensors such as a CO sensor that detects the concentration of carbon monoxide in exhaust gas. Some exhaust gas sensors of this type are affected by the output due to changes in the flow rate of exhaust gas in the vicinity of the exhaust gas sensor.

  Therefore, in the situation where the exhaust gas sensor is provided using the packing, when exhaust gas leaks from the packing part due to deterioration of the packing or the like, accurate measurement cannot be performed unless this is detected. In other words, when the exhaust gas leaks from the packing part, the flow of the exhaust gas changes as compared with the case where the packing functions normally, and therefore there is a risk of causing an error in the output of the exhaust gas sensor due to the difference in the flow velocity of the exhaust gas sensor. .

Japanese Patent Laid-Open No. 9-5278

  The problem to be solved by the present invention is that when there is a packing in the installation part of the exhaust gas sensor for detecting the concentration of carbon monoxide or the like contained in the exhaust gas from the combustion equipment, the leakage of the exhaust gas from the packing part to the outside It is in judging.

  The present invention has been made in order to solve the above-mentioned problems, and the invention according to claim 1 is an installation part of an exhaust gas sensor for detecting the concentration of carbon monoxide, carbon dioxide, oxygen or nitrogen oxide in exhaust gas. An exhaust gas measuring device having a packing, and the exhaust gas measuring device is applied to a system provided in an exhaust gas path from a combustion device, and determines a leak of exhaust gas from the location of the packing to the outside, The exhaust gas sensor is a sensor that is affected by an output due to a change in the flow rate of the exhaust gas. Based on the output of the exhaust gas sensor while the combustion device is stopped and the output of the exhaust gas sensor during the pre-purge of the combustion device, It is a packing leakage determination method for an exhaust gas sensor installation section, wherein leakage of exhaust gas from a packing portion to the outside is determined.

  According to the first aspect of the present invention, the leakage of the exhaust gas from the packing part to the outside is determined based on the output of the exhaust gas sensor while the combustion device is stopped and the output of the exhaust gas sensor during the pre-purge of the combustion device. Can do. In other words, the fuel is not combusted during both stoppage and pre-purge, so the exhaust gas sensor is exposed to the same environment as the outside air, and the output of the exhaust gas sensor should be the same, but the output exceeds the set value. If a difference arises, it can be determined that the influence of the flow velocity change due to leakage from the packing portion.

  The invention according to claim 2 is the packing leak determination method of the exhaust gas sensor installation part according to claim 1, wherein the output at the end of the pre-purge is used as the output of the exhaust gas sensor during the pre-purge. .

  According to the second aspect of the present invention, the output at the end of the pre-purge for releasing the gas accumulated in the combustion equipment to the outside is adopted as the output of the exhaust gas sensor during the pre-purge, so that the gas is accumulated in the combustion equipment. This makes it possible to accurately determine the leakage from the packing portion by preventing the influence of the gas.

  The invention according to claim 3 is characterized in that the combustion device is a boiler or a water heater, and the exhaust gas sensor is a catalytic combustion type CO sensor. This is a method for determining a packing leakage at a sensor installation portion.

  According to the third aspect of the present invention, the carbon monoxide concentration is accurately measured for the catalytic combustion type CO sensor in the boiler or water heater while monitoring the leakage of the exhaust gas from the packing of the sensor installation portion. be able to.

  Furthermore, the invention described in claim 4 is provided with an exhaust gas measuring device having a packing at an installation portion of an exhaust gas sensor for detecting the concentration of carbon monoxide, carbon dioxide, oxygen or nitrogen oxide in the exhaust gas. Is applied to a system provided in an exhaust gas path from a combustion device, and is a program for judging leakage of exhaust gas from the location of the packing to the outside, and the exhaust gas sensor affects the output by a change in the flow rate of exhaust gas. A step of detecting an output of the exhaust gas sensor immediately before the pre-purge of the combustion device, a step of detecting an output of the exhaust gas sensor during the pre-purge of the combustion device, and the exhaust gas sensor detected in each step Determining leakage of exhaust gas from the location of the packing to the outside based on the difference in output of Is a program to be executed by a computer.

  According to the invention described in claim 4, the leakage of the exhaust gas from the packing part to the outside is determined based on the output of the exhaust gas sensor while the combustion device is stopped and the output of the exhaust gas sensor during the pre-purge of the combustion device. Can do. In other words, the fuel is not combusted during both stoppage and pre-purge, so the exhaust gas sensor is exposed to the same environment as the outside air, and the output of the exhaust gas sensor should be the same, but the output exceeds the set value. If a difference arises, it can be determined that the influence of the flow velocity change due to leakage from the packing portion.

  According to the present invention, when there is a packing in the installation part of the exhaust gas sensor that detects the concentration of carbon monoxide or the like contained in the exhaust gas from the combustion device, the leakage of the exhaust gas from the packing part to the outside is determined. Can do.

It is the schematic which shows one Example of the system with which the packing leak determination method of this invention is applied. It is a perspective sectional view which expands and shows the base end part of the exhaust gas measuring device in the system of FIG. It is the schematic which shows an example of the relationship between the output of an exhaust gas sensor, and elapsed time.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an embodiment of a system to which the packing leakage determination method of the present invention is applied.

  The packing leakage determination method of the present embodiment is applied to a system in which an exhaust gas measuring device 3 is provided in an exhaust gas path (exhaust cylinder 2) from the combustion device 1. The combustion device 1 is a device that burns fuel such as oil or gas, and the type thereof is not particularly limited, but is typically a boiler 4 or a water heater.

  In the illustrated example, the combustion device 1 is a boiler 4, and the boiler 4 includes a can body 5, a burner 6, a blower 7, and the like. The burner 6 is supplied with fuel such as oil or gas and combustion air from the blower 7 and burns the fuel in the can 5. Thereby, the water in the can 5 is heated and vaporized. Then, the steam is sent to various steam use facilities. The exhaust gas after combustion in the can 5 is discharged to the outside through the exhaust cylinder 2. In addition, when the combustion apparatus 1 is a hot water heater, it can be said that it is the same structure, although the point which replaces with steam and obtains warm water differs.

  The exhaust gas path is typically composed of an exhaust stack 2, ie a flue or chimney. In order to detect the concentration of carbon monoxide, carbon dioxide, oxygen or nitrogen oxide in the exhaust gas, an exhaust gas measuring device 3 is attached to the exhaust pipe 2.

  The exhaust gas measuring device 3 includes an exhaust gas sensor 8 that detects the concentration of carbon monoxide, carbon dioxide, oxygen, or nitrogen oxide in the exhaust gas. The packing leak judgment method of the present invention functions effectively because the exhaust gas sensor 8 is affected by the output due to the change in the flow rate of the exhaust gas to the exhaust gas sensor 8, such as a catalytic combustion type CO sensor. It is.

  The exhaust gas sensor 8 may be provided directly on the peripheral side wall of the exhaust pipe 2 or a measurement port provided on the exhaust pipe 2, but in this embodiment, the exhaust gas sensor 8 is provided on the peripheral side wall of the exhaust pipe 2 via the extraction pipe 9. In any case, the exhaust gas sensor 8 is attached via the packing 10 so that the exhaust gas does not leak from the installation portion of the exhaust gas sensor 8 to the outside.

  The extraction pipe 9 in the illustrated example is provided so as to be inclined upward as it is separated from the peripheral side wall of the exhaust pipe 2. The extraction pipe 9 is configured such that a part of the exhaust gas passing through the exhaust pipe 2 is taken out via the take-out path 11, folded back at the end of the take-out path 11, and returned to the exhaust pipe 2 through the return path 12. . And the exhaust gas sensor 8 is provided downward in the upward recess 13 (FIG. 2) provided in the return path 12.

  FIG. 2 is an enlarged perspective sectional view of the base end portion of the exhaust gas measuring device 3. As shown in FIGS. 1 and 2, the extraction pipe 9 of the present embodiment includes an outer pipe 14 having a rectangular cross section and an inner pipe 15 having a rectangular cross section that is fitted into the lower half of the cross section of the outer pipe 14. The outer pipe 14 is closed at the proximal end portion by the end wall 16, while the distal end portion is opened. On the other hand, the inner pipe 15 is arranged such that the base end portion is spaced apart from the end wall 16, so that a folded opening 17 is formed between the base end portion of the inner pipe 15 and the end wall 16 of the outer pipe 14. Is done. Further, the inner pipe 15 is provided so as to extend sufficiently more than the distal end portion of the outer pipe 14, and the distal end portion is opened.

  With such a configuration, if the tip ends of the outer pipe 14 and the inner pipe 15 are opened into the exhaust tube 2, the inside of the inner pipe 15 is inside the take-out path 11, the outer pipe 14 and the inner pipe 15 outside. Functions as the return path 12. That is, the exhaust gas in the exhaust pipe 2 is introduced from the distal end portion of the inner pipe 15, moves from the distal end portion of the inner pipe 15 to the proximal end portion, and is led out from the folding opening 17 to the outer pipe 14 outside the inner pipe 15, The outer pipe 14 moves from the proximal end portion to the distal end portion, and is returned from the distal end portion of the outer pipe 14 into the exhaust tube 2. In FIG. 1, the distal end portion of the outer pipe 14 is opened in the peripheral side wall of the exhaust tube 2, and the distal end portion of the inner pipe 15 is opened in a state of being plunged into the exhaust tube 2.

  An exhaust gas sensor 8 is provided on the extraction pipe 9 via a sensor mounting cylinder 18. The sensor mounting cylinder 18 has a cylindrical shape or a rectangular tube shape, and includes flanges (a lower flange 19 and an upper flange 20) at both axial ends. In the sensor mounting cylinder 18, the lower flange 19 is fixed to the upper wall 21 of the outer pipe 14 in an airtight state. The upper wall 21 of the outer pipe 14 is previously drilled at a position corresponding to the hollow hole of the sensor mounting cylinder 18. In this manner, the upward recess 13 is provided in the exhaust gas return path 12.

  The exhaust gas sensor 8 is provided in the concave portion 13 constituted by the hollow hole of the sensor mounting cylinder 18. In the present embodiment, the exhaust gas sensor 8 is provided with a flange 23 at the upper end of a cylindrical main body 22. Therefore, in the exhaust gas sensor 8, the main body 22 is inserted into the hollow hole of the sensor mounting cylinder 18 from above, and the flange 23 is overlapped with the upper flange 20 of the sensor mounting cylinder 18 via the packing 10 and fixed with the screws 24. Is done. By sandwiching the packing 10 between the flanges 20 and 23, the gap between the flanges 20 and 23 is sealed, and the exhaust gas is prevented from escaping to the outside via the sensor mounting cylinder 18.

  The exhaust gas sensor 8 is connected to a controller (not shown), and the controller leaks exhaust gas from the location of the packing 10 of the installation portion of the exhaust gas sensor 8 to the outside based on the output of the exhaust gas sensor 8 according to a predetermined program. Is detected. Hereinafter, this packing leakage determination method will be described.

  FIG. 3 is a schematic diagram illustrating an example of the relationship between the output of the exhaust gas sensor (for example, the catalytic combustion CO sensor) 8 and the elapsed time. As shown in this figure, normally, the combustion device 1 shifts from the stopped state (standby) S1 to the combustion step S3 via the pre-purge step S2.

  During the stop S1 of the combustion equipment, the burner 6 and the blower 7 are stopped. On the other hand, in the pre-purge process S2, the blower 7 is operated with the burner 6 stopped. That is, in the state where the combustion of the fuel by the burner 6 is stopped, air is sent from the blower 7 into the can body 5 and released from the exhaust cylinder 2, thereby ventilating the inside of the can body 5 and the exhaust cylinder 2. Thereafter, the burner 6 is operated, the fuel from the burner 6 is ignited, and the routine proceeds to a combustion step S3 where the fuel from the burner 6 is combusted. In the combustion step S3, the amount of combustion may be adjusted as appropriate.

  The fuel is not burned during the stop S1 of the combustion device 1 or during the pre-purge step S2. Therefore, the exhaust gas sensor 8 is exposed to the same environment as the outside air, and the output of the exhaust gas sensor 8 should be equivalent. Ideally, as indicated by line A in FIG. 3, the output of the exhaust gas sensor 8 during the pre-purging step S2 is not different from the output of the exhaust gas sensor 8 during the stop S1.

  However, it is assumed that exhaust gas leaks from the location of the packing 10 due to deterioration of the packing 10 or the like. In this case, since the exhaust gas leaks outside through the exhaust gas sensor 8, the output of the exhaust gas sensor 8 is an output affected by the flow velocity. For example, as shown by line B or line C in FIG. 3, the output is deviated from the ideal state (line A) described above.

  Therefore, the leakage of the exhaust gas from the location of the packing 10 to the outside is determined based on the output of the exhaust gas sensor 8 during the stop S1 of the combustion device 1 and the output of the exhaust gas sensor 8 during the pre-purging step S2 of the combustion device 1. Can do. Specifically, the controller obtains the output of the exhaust gas sensor 8 during the stop S1 and the output of the exhaust gas sensor 8 during the pre-purging step S2, and if a difference greater than the setting occurs between the two, the packing unit 10 It is determined that there is a leak. If it is determined that there is a leak, an alarm to that effect may be issued to request maintenance.

  By the way, in the initial stage of the pre-purge process S2, there is a possibility of being affected by the gas remaining in the can 5 so that the output at the final stage of the pre-purge process S2 (for example, time T2 in FIG. 3) and the stop (for example, It is preferable to compare the output with the time T1) immediately before the pre-purge.

  As described above, the controller includes a program for determining leakage of exhaust gas from the location of the packing 10 to the outside, and this program enables determination of packing leakage as described above. That is, the step of detecting the output of the exhaust gas sensor 8 while the combustion device 1 is stopped (for example, time T1 immediately before the pre-purge) and the output of the exhaust gas sensor 8 during the pre-purge process S2 of the combustion device 1 (for example, the time T2 at the end of the pre-purge). And a step of judging leakage of exhaust gas from the location of the packing 10 to the outside based on the difference in output of the exhaust gas sensor 8 detected in each step.

  According to the packing leakage determination method and its program of the present embodiment, it is possible to easily determine the leakage of exhaust gas from the packing 10 to the outside in the installation portion of the exhaust gas sensor 8. In addition, the output of the exhaust gas sensor 8 affects not only the gas flow rate to the exhaust gas sensor 8 but also the temperature, etc. By comparing the output in the pre-purge step S2 of the combustion device 1 with the output immediately before it, the temperature etc. It becomes the composition which is not influenced by.

  The packing leak determination method and program for the exhaust gas sensor installation section of the present invention are not limited to the configuration of the above-described embodiment, and can be changed as appropriate. In particular, the configuration in which the exhaust gas sensor 8 is provided in the exhaust gas path from the combustion device 1, for example, the extraction pipe 9 and the attachment structure of the exhaust gas sensor 8 to the extraction pipe 9 can be appropriately changed. In short, the configuration of the combustion device 1 and the exhaust gas measuring device 3 can be changed as appropriate as long as the system includes the packing 10 in the installation part of the exhaust gas sensor 8 that is affected by the output due to the change in the flow rate of the exhaust gas.

1 Combustion equipment 2 Exhaust tube (exhaust gas path)
DESCRIPTION OF SYMBOLS 3 Exhaust gas measuring device 4 Boiler 8 Exhaust gas sensor 9 Extraction pipe 10 Packing S1 Stopping of combustion equipment S2 Prepurge process S3 Combustion process

Claims (4)

An exhaust gas measuring device having a packing is provided at the installation part of the exhaust gas sensor for detecting the concentration of carbon monoxide, carbon dioxide, oxygen or nitrogen oxide in the exhaust gas, and this exhaust gas measuring device is provided in the exhaust gas path from the combustion equipment. A method for determining leakage of exhaust gas from a location of the packing to the outside applied to a system,
The exhaust gas sensor is a sensor that is affected by output due to a change in the flow rate of exhaust gas,
Exhaust gas leaking from the location of the packing to the outside is determined based on the output of the exhaust gas sensor when the combustion device is stopped and the output of the exhaust gas sensor during pre-purge of the combustion device. Packing leak judgment method for the sensor installation part. The packing leak determination method for an exhaust gas sensor installation unit according to claim 1, wherein the output at the end of the pre-purge is used as the output of the exhaust gas sensor during the pre-purge. The combustion device is a boiler or a water heater,
The said exhaust gas sensor is a contact combustion-type CO sensor. The packing leak determination method of the exhaust gas sensor installation part of Claim 1 or Claim 2 characterized by the above-mentioned. An exhaust gas measuring device having a packing is provided at the installation part of the exhaust gas sensor for detecting the concentration of carbon monoxide, carbon dioxide, oxygen or nitrogen oxide in the exhaust gas, and this exhaust gas measuring device is provided in the exhaust gas path from the combustion equipment. A program that is applied to a system and determines leakage of exhaust gas from a location of the packing to the outside,
The exhaust gas sensor is a sensor that is affected by output due to a change in the flow rate of exhaust gas,
Detecting the output of the exhaust gas sensor immediately before the pre-purge of the combustion device;
Detecting the output of the exhaust gas sensor during pre-purge of the combustion device;
A program for causing a computer to execute a step of determining leakage of exhaust gas from the location of the packing to the outside based on a difference in output of the exhaust gas sensor detected in each step.

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