JPH0334679Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a gas permeability measuring device installed in a gas flow path such as a flue in various combustion mechanisms.

(Prior Art) As is well known, in various combustion mechanisms mainly for industrial use, in order to prevent environmental pollution and improve combustion efficiency,
Various types of detection are performed regarding combustion exhaust gas. For example, by placing an exhaust gas oxygen concentration analyzer, exhaust gas carbon monoxide concentration analyzer, exhaust gas permeability meter, etc. in the flue alone or in combination, the supply of fuel and air can be optimized while collecting various data in the exhaust gas. The operation is managed as follows.

Among these, exhaust gas permeability meters are easy to install and simple, and are widely used in flues of boilers, incinerators, coke ovens, etc.

For example, an example of installing an exhaust gas permeability meter in the flue of a coke oven is shown in FIG. 5 of Japanese Patent Application Laid-Open No. 151785/1985. In this configuration, the gas permeability meter consists of a light emitter and a light receiver, and two flanged short tubes are installed facing each other in a position in the flue where the flow of exhaust gas is uniform. and a light receiver, and the inside of each short tube is always filled with a purge gas such as nitrogen at a pressure approximately equal to the internal pressure of the flue. According to such a configuration, a constant light beam is always projected from the light projector to the light receiver, and the amount of light that reaches the light receiver is converted into an electrical signal. Since the amount of light reaching the receiver changes proportionally due to changes in the content of soot, dust, etc. contained in the exhaust gas, the electrical signal conversion value from the amount of light reached is output to a recorder etc. to continuously It monitors and controls the supply of fuel and air to the combustion mechanism to optimize combustion management. Furthermore, if each short tube is filled with purge gas to make the internal pressure approximately equal to the internal pressure of the flue, the exhaust gas in the flue will not be introduced into the short tube, making it difficult for the projector and receiver to be contaminated by soot and dust.

(Problems to be Solved by the Invention) However, even the above-mentioned device does not have reliable reliability in long-term use.

The reason for this is that, over a long period of time, dust and the like accumulate at the installation opening at the tip of the short tube, and the area required for measurement gradually decreases, resulting in an error in the amount of light reaching the light receiver. In addition, when various conditions occur in the combustion mechanism and the flue gas increases rapidly and the internal pressure of the flue rises, the internal pressure of each short pipe decreases relatively, causing the exhaust gas to flow into the short pipe and reduce the exhaust gas. The contained soot and dust stains the lenses of the emitter and receiver. Therefore, subsequent measurements are impossible and it cannot be used. Furthermore, when the composition of the exhaust gas flowing through the flue changes and the dew point decreases, condensed water is generated in the flue and flows to each short tube, staining the lenses of the emitter and receiver, so do not use it afterward as above. Can not do it.

In order to solve the above-mentioned problems, the supply of purge gas is controlled by operating a solenoid valve when the exhaust gas pressure rises or at regular intervals using a timer, but this increases the equipment cost and operating cost. It is not a sufficient solution.

(Means for Solving the Problem) The present invention was proposed in view of the above, and includes a light projector having a light projecting element and a light receiver having a light receiving element facing each other in the gas flow path. By providing an annular cavity filled with purge gas on the outer periphery of the tip of each passage provided in the vessel, and attaching a flange portion having a through hole of approximately the same diameter that communicates with the passage on the outside, the tip of the passage and An annular purge gas outflow hole is formed between the projector and the flange, and a diaphragm mechanism is individually interposed on the outside of the hole to have a diaphragm that is narrowed to the extent that it does not prevent the receiver from receiving the light source from the projector. A gas permeability measuring device is provided.

(Example) An example of the present invention will be described below based on the drawings.

In FIG. 1, 1 is a combustion section of the combustion mechanism, 2 is a gas flow path shown as a flue through which the exhaust gas generated in the combustion section 1 flows upward, and there are two short paths in the middle of the gas flow path 2. The tubes 3 and 3 are provided facing each other, and a light projector 5 and a light receiver 6 are attached to the flange 4 at the tip of each short tube 3.

The light emitter 5 has a lamp and other light emitting elements inside, and the light receiver 6 has a transistor and other light receiving elements inside. A purge gas supply port 7 is connected to the tips of the light projector 5 and the light receiver 6.

FIG. 2 is an enlarged partial cross-section of the projector 5. A passage 8 is formed in the projector 5, and an annular cavity 9 is provided on the outer periphery of the tip of the passage 8. 9 is connected to the purge gas supply port 7 described above. A flange portion 10 is attached to the tip of the projector 5, and a through hole 11 opened at the center of the flange portion 10 is communicated with the passage 8. A slope 12 is formed on the inner periphery of the above-mentioned through hole 11 so that the diameter decreases from the surface toward the inside of the thickness, and between the slope 12 and the inner peripheral edge of the opening end of the above-mentioned cavity 9. A fine annular outflow hole 13 is formed.

On the other hand, a throttle mechanism 14 is attached to the short tube 3 described above. This throttle mechanism 14 consists of a cylindrical part 15 housed inside the short tube 3, and a plate-shaped throttle part 16 provided at the end of the cylindrical part 15. and a diaphragm 17 having a smaller diameter than the cylindrical portion 15.
will be established. In order to interpose the aperture mechanism 14 described above between the light receiver 5 and the gas flow path 2, the cylindrical part 15 is inserted into the short pipe 3 from the tip thereof, and a flange-shaped part extending around the outer periphery of the aperture part 16 is inserted. The flange-like portion 16' extending around the outer circumference of the flange 4 is brought into close contact with the outer surface of the flange 4, and the ring-shaped packing 18 and the flange portion 10 of the projector 5 are superimposed on the outer surface of the flange-like portion 16'. Several bolts (not shown) are passed in series from the flange 4 to the flange portion 10 and tightened.

Therefore, the diaphragm mechanism 14 is located inside the short tube 3 and interposed between the gas flow path 2 and the floodlight 5, and the diaphragm opening 17 of the diaphragm portion 16 has a smaller diameter than the cylindrical portion 15 and the through hole 11. The above-mentioned configuration is exactly the same on the light receiver 6 side, only that the light projector 5 is replaced by the light receiver 6.

The above-mentioned aperture mechanism may be made of any material as long as it is heat resistant; for example, it can be manufactured by processing a thin iron plate. The diaphragm 17 of the diaphragm 16 may be of a size that does not obstruct the receiver 6 from receiving the light source from the projector 5, for example, the cylindrical portion 14, the passage 8, etc.
Alternatively, it may be about half the area of the through hole 11.

Although the above-mentioned embodiment describes an optical measuring device, the present invention is not limited thereto and can be modified as appropriate within the scope of the gist. You can.

(Effects of the invention) In summary, according to the invention, an aperture is provided between the emitter and the gas flow path and between the light receiver and the gas flow path to the extent that the light source from the emitter is not obstructed by the receiver. Since the aperture mechanisms each having a section are individually interposed, even if purge gas is supplied from the light projecting section or the light receiving section to the inside of the short tube, the flow velocity of the purge gas increases at the constriction section. Therefore, even if the exhaust gas pressure rises in the gas flow path and flows into the short pipe, it will not flow from the constriction part to the emitter or receiver, and even if dust etc. accumulates inside the constriction mechanism, it will not flow into the short pipe. Since the diaphragm functions as a protective wall, the lenses of the projector and receiver will not be contaminated by dust or the like. Furthermore, even if dew condensation occurs in the gas flow path and flows into the diaphragm mechanism, the diaphragm prevents the water from flowing into the projector or receiver.

Therefore, there is no measurement error even after a long period of time.
It is extremely reliable and of high practical value.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic front view of a partially sectional view, and FIG. 2 is a cross-sectional view of the main part. 2... Gas flow path, 5... Emitter, 6... Light receiver, 14... Aperture mechanism, 16... Aperture section.

Claims (1)

[Scope of utility model registration request] A light emitter having a light emitting element and a light receiver having a light receiving element face each other in a gas flow path, and an annular cavity is filled with purge gas around the outer periphery of the tip of each passage provided in the emitter and the light receiver. A ring-shaped purge gas outflow hole is formed between the tip of the passage and the flange by attaching a flange part having a through hole of approximately the same diameter that communicates with the passage to the outside of the flange. A gas permeability measurement device that is individually equipped with a diaphragm mechanism having an aperture portion that is narrowed down to the extent that it does not interfere with the reception of a light source by a light receiver.