JP5041899B2 - Opacimeter - Google Patents

Description

  The present invention relates to an opacimeter (light transmission type black smoke measuring device) for measuring the concentration of particulate matter such as black smoke contained in exhaust gas discharged from a diesel vehicle, for example.

Currently, problems caused by exhaust gases emitted by specific vehicles, especially air pollution caused by large amounts of exhaust gases and dust emitted from vehicles equipped with large diesel engines, are regarded as important from the viewpoint of human health and global environmental conservation. Emissions of carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NO _x ), particulate matter (PM) and other specific components emitted from vehicles are subject to regulation. ing.

  For example, when inspecting the amount (concentration) of black smoke discharged from a diesel vehicle, for example, the light is reflected on the “measurement principle paper” to which black smoke in the exhaust gas is adhered, and the reflectance Based on this, black smoke concentration measurement using a black smoke measuring device that measures the black smoke concentration has been carried out, but for recent diesel cars where exhaust gas reduction technology has advanced and black smoke is hardly emitted The actual situation is that measurement using such a “reflective” black smoke measuring instrument is becoming difficult.

  In recent years, as a method for measuring exhaust gas, a light transmission type black smoke measuring device that transmits light into exhaust gas and measures the concentration of particulate matter such as black smoke contained in the exhaust gas based on the transmittance. (Opacimeter) is used to measure the emission of particulate matter such as nitrogen oxides and black smoke in line with the actual driving conditions of automobiles. It is possible to measure organic soluble components (SOF components), which are unburned components of diesel oil and lubricating oil, which are becoming increasingly important to measure, as well as being able to meet the PM regulation values. Various configurations have been proposed so far (see, for example, Patent Document 1).

In a certain type of such an opacimeter, for example, as shown in FIG. 8, the exhaust gas G having a gas introduction port 72A for introducing the exhaust gas G at the central position in the length direction thereof circulates. A cylindrical gas flow path forming material 71 that defines the gas flow path 72 is provided, and a light emitting unit 74 including a light source 73 is provided at an outer position of the one end side opening of the gas flow path forming material 71, and A light receiving unit 76 including a light detection sensor 75 is provided outside the opening on the other end side of the gas flow path forming member 71 so as to face the light source 73 via the gas flow path 72. It is configured.
In the opacimeter having the above-described configuration, for example, a light-emitting unit side lens (not shown) that causes the light from the light source 73 to enter the gas flow path 72 as parallel light is provided in the light emission section 74 and from the gas flow path 72. A light receiving unit side lens (not shown) that collects parallel light and enters the light detection sensor 75 is provided in the light receiving unit 76, and the light emitting unit side lens and the light receiving unit side lens are exposed. Therefore, in order to prevent the lens from being contaminated by the exhaust gas G exhausted from the gas flow path 72, the gap between the one end side opening of the gas flow path forming material 71 and the light emitting portion 74, and In each of the gaps between the opening on the other end side and the light receiving portion 76, the purge air PA is circulated in a direction (vertical direction in the drawing) perpendicular to the direction in which the gas flow path forming material 71 extends.
Such an opacimeter is used on the ground (floor surface) with an exhaust port 81 formed in the outer casing 80 facing downward in order to prevent external light from entering in an automobile maintenance shop or the like. Used to put on.

JP 2004-184119 A

Thus, although the purge air PA is configured to flow in the opacimeter having the above configuration, the exhaust gas G from the gas flow path 72 is blown out toward the light emitting unit side lens and the light receiving unit side lens. Therefore, the degree of contamination of the light emitting unit side lens and the light receiving unit side lens by the exhaust gas G is large, and it is necessary to clean it appropriately.
This cleaning operation is performed, for example, by the operator wiping with a dry cloth or felt impregnated with an appropriate solvent.
However, both the light-emitting unit side lens and the light-receiving unit side lens are arranged in a state in which the lens surface is in the vertical direction at a depth of about several centimeters (inside) of the exhaust port 81 that opens to the outer casing 80 of the opacimeter. Therefore, there is a problem that cleaning is very difficult and it is difficult to obtain a sufficient cleaning result.

  On the other hand, there is a structure in which the lens surface can be exposed by making the light emitting unit and the light receiving unit detachable or openable from the outer casing, but such a structure is formed on the outer casing of the opacimeter. There is a problem that the reproducibility of the mounting state of the light emitting unit and the light receiving unit is gradually deteriorated, and the alignment of the optical axis may not be obtained.

  The present invention has been made based on the above circumstances, and can easily and surely wipe the optical system member constituting the detection unit in the measuring instrument, and the cleaning result thereof. This makes it possible to maintain the detector in a suitable state free from contamination by exhaust gas, and thus provide an opacimeter that can perform reliable exhaust gas measurement with high reliability. The purpose is to do.

Opashimeta of the present invention, particulate matter more exhaust gas to be detected light emitting portion and a light receiving portion so that the optical path is formed is provided in a measurement chamber where the exhaust gas is introduced, the degree of attenuation of the measurement light detection unit for measuring the concentrations, in Opashimeta having a measuring device comprising disposed within the cover hood,
In the measuring instrument, on the both sides of the outer casing, the outer casing is opened on the both sides of the outer casing in a state where the exhaust opening opened to the outer casing faces downward and the exhaust outlet is separated from the ground or floor surface. Support legs are provided to support, and the support legs are configured to be able to support the outer casing in a state where one or the other side surface is a lower surface .
The light-emitting unit and the light-receiving unit have a light-transmitting or reflecting optical system member, and the optical system member is positioned in a state exposed to a space following the exhaust port, and one or the other side surface of the outer casing The optical system member is visible through the exhaust port in a state where is the lower surface .

  According to the opacimeter of the present invention, the outer casing is supported on the ground surface or the floor surface with one or the other side surface being the lower surface, and the optical system member constituting the light emitting unit or the light receiving unit is directed upward, for example. In addition, since the optical system member can be cleaned, the operator can wipe the optical system member very easily and reliably while visually observing the optical system member through the exhaust port in the outer casing. As a result of being able to easily confirm the cleaning result, it is possible to maintain the detection unit in an appropriate state free from contamination by the exhaust gas, and therefore it is possible to perform the intended exhaust gas measurement with high reliability.

FIG. 1 is a front view showing an overview of an example of a measuring instrument constituting the opacimeter of the present invention, FIG. 2 is a rear view of the measuring instrument shown in FIG. 1, and FIG. 3 is a right side view of the measuring instrument shown in FIG. FIG. 4 is an explanatory view schematically showing the internal structure of the measuring instrument shown in FIG.
This opacimeter uses, for example, exhaust gas discharged from a diesel engine mounted in an automobile as a gas to be inspected, and displays a measurement device 10 that detects the concentration of fine particles in the exhaust gas, and a measurement result by the measurement device 10. The measuring instrument 10 includes a box-shaped outer casing 11 having a substantially rectangular parallelepiped shape, and the inner space of the outer casing 11 is partitioned vertically by a partition wall 12. Thus, an upper chamber 13 and a lower chamber 14 are formed.
A flat signal processing board 15 is arranged in the upper chamber 13 in the outer casing 11 so as to extend in the longitudinal direction (left-right direction in FIG. 4) along the upper wall of the outer casing 11, and this signal processing board. 15, the two blower fans 18 are arranged side by side in the longitudinal direction with the blower ports facing downward, and the blower ports of the blower fan 18 are arranged on the partition wall 12. It is exposed in the lower chamber 14 through the formed opening.

In the lower chamber 14 in the outer casing 11, for example, an exhaust gas discharged from a diesel engine mounted on an automobile is used as a test gas, and a detection unit 20 that detects the concentration of fine particles in the exhaust gas is disposed. .
The detection unit 20 is, for example, a rectangular tube-shaped measurement chamber forming material 21 that defines a measurement chamber 21 </ b> A therein, and a longitudinal center position in the measurement chamber forming material 21. A rectangular tube-shaped gas flow path forming material 22 that defines a gas flow path 22 </ b> A through which exhaust gas flows, and one end of the gas flow path forming material 22 and the outer side in the longitudinal direction at one end side opening of the measurement chamber forming material 21. The light emitting unit 25 arranged in a state of being separated from the side and the other end side opening of the measurement chamber forming material 21 are arranged in a state of being spaced apart from the other end of the gas flow path forming material 22 in the longitudinal direction. The light receiving unit 30 is provided, and an exhaust gas introduction port 28 for introducing exhaust gas into the measurement chamber 21A, specifically, the gas flow path 22A, is formed at the center position in the longitudinal direction.
On the upper and lower walls of the measurement chamber forming material 21, a gap between one end of the gas flow path forming material 22 and the light emitting unit 25 and a gap between the other end of the gas flow path forming material 22 and the light receiving unit 30 are provided. Openings are formed at positions corresponding to each of the openings, each of the openings on the upper wall is aligned with each of the air outlets of the blower fan 18, and each of the openings on the lower wall is formed on the outer casing 11. It is in a state of being aligned with each of the exhaust ports 16 formed in the lower wall, and thereby, from the blower fan 18 in a direction (vertical direction in FIG. 4) perpendicular to the flow direction of the exhaust gas in the gas flow path 22A. The purge air is circulated.

The light emitting unit 25 includes a light source 26 made of, for example, an LED (light emitting diode) or a laser irradiation device, and a light emitting unit side lens 27 that causes the light from the light source 26 to enter the gas flow path 22A as parallel light. The light emitting unit side lens 27 is exposed in the measurement chamber 21A.
The light receiving unit 30 is made of, for example, a photodiode, and collects parallel light from the light receiving sensor 31 provided to face the light source 26 via the gas flow path 22A and the measurement chamber 21A and enters the light receiving sensor 31. A light receiving unit side lens 32 to be exposed, and the light receiving unit side lens 32 is exposed in the measurement chamber 21A.
That is, an optical member having translucency or reflectivity is positioned on the circumferential side of the space that continues to the exhaust port 16 in the outer casing 11.

  In the above, the reference numeral 40 shown in FIG. 1 to FIG. 4 is a carrying grip part, 41 is an air introduction part, 42 is a power switch, 43 is a communication connector, 44 is a power output part, and 45 is a power input part. 46 are sampling tube connections.

Thus, in the measuring instrument 10 according to the opacimeter having the above configuration, the support legs 50 are provided on both side surfaces of the outer casing 11.
At the time of measurement, the support leg 50 supports the outer casing 11 in a state in which the exhaust port 16 faces downward, and the exhaust port 16 is separated from the ground or floor surface, thereby preventing the exhaust from being inhibited. For example, the outer casing 11 can be supported on the ground surface or the floor surface in a state where one or the other side surface is a lower surface when the optical system member constituting the detection unit 20 is cleaned, for example. .
Specifically, the configuration of the support leg 50 is substantially V-shaped as a whole. The central bent portion 51 is curved in an arc shape so as to be convex upward, and is continuous to both ends of the central bent portion 51. And a leg portion 52 provided with a rubber cap 53 at the leading end thereof, and a rubber cap provided on each leg portion 52 at the time of cleaning (see FIG. 6) is provided on the top side surface of the central bent portion 51. A support portion 55 that abuts against a horizontal plane (the ground surface or the floor surface) together with 53 is provided.
With such a configuration, it is possible to support the outer casing 11 of the measuring instrument 10 in a state in which the side surface is the lower surface and is always supported in a stable posture.

In the configuration example of the measuring instrument 10, the outer casing 11 has a dimension in the height direction (vertical direction in FIG. 1) of approximately 200 mm, a dimension in the lateral direction (horizontal direction in FIG. 1) of approximately 420 mm, and a longitudinal direction ( The dimension in the left-right direction in FIG. 3 is about 90 mm.
The length of the optical path portion formed in the gas flow path 22A in the gas flow path forming material 22 (the optical path length of the optical path portion (effective optical path) related to light passing through the exhaust gas atmosphere is 215 to 281 mm, for example, The flow rate of the exhaust gas G flowing through 22A is, for example, 10 to 100 liters / minute, and the flow rate of the purge air PA is the same on one end side and the other end side, for example, 300 to 1000 liters / minute.
Moreover, the weight of the measuring device 10 is about 3-8 kg, for example.

As shown in FIG. 5, for example, the measuring instrument 10 is connected to the exhaust pipe of the test vehicle 60 by the sampling tube 48, and the power line and the signal line are connected to the display device 65 for displaying the exhaust gas measurement result. The signal transmission cable 66 is used by being connected. The signal transmission between the measuring instrument 10 and the display device 65 may be performed by wireless communication.
During the detection operation, the measuring instrument 10 according to this opacimeter emits light from the light source 26, and the exhaust gas G is introduced into the gas flow path 22A via the gas introduction port 28 so as to be out of the longitudinal direction. The light emitted from the light source 26 enters the gas flow path 22A as parallel light through the light emitting unit side lens 27 and is parallel to the gas flow path 22A. Light is incident on the light receiving sensor 31 via the light receiving unit side lens 32. In the process in which the light emitted from the light source 26 passes through the gas flow path 21A, the light is blocked by fine particles present in the exhaust gas G. The progress is hindered, and the light receiving sensor with respect to the amount of light emitted from the light source 26 is utilized by utilizing the fact that the amount of light incident on the light receiving sensor 31 decreases corresponding to the concentration of the particulate matter in the exhaust gas G. 31 the concentration of the particulate matter is detected by measuring the amount of light (opacity) of light incident on, the result is displayed on the display device 65.
Here, during such a detection operation, the purge air PA supplied by the blower fan 18 is inserted into each of the gaps between the gas flow path forming material 22 and the light emitting unit side lens 27 and the light receiving unit side lens 32. It is circulated at an appropriate flow rate and circulates toward the exhaust port 16 that opens to the outer casing 11. As a result, the exhaust gas G in the state of flowing through the gas flow path 22A flows toward the light emitting unit 25 and the light receiving unit 30, but an air curtain is formed by the purge air PA. The degree of contact with the optical system member, specifically, the light emitting unit side lens 27 and the light receiving unit side lens 32 can be reduced.

  In the cleaning operation, the measuring instrument 10 supports the outer casing 11 on the floor (or the ground) F, with one or the other side being the lower side, as shown in FIG. For example, it is performed by the operator wiping the light-emitting unit side lens 27 or the light-receiving unit side lens 32 with a dry cloth or felt impregnated with an appropriate solvent.

  Thus, according to the opacimeter having the above-described configuration, at the time of measurement, the outer casing 11 of the measuring instrument 10 is exhausted while being supported in a state where the exhaust port 16 faces downward and is separated from the ground or the floor surface. The support leg 50 is capable of supporting the outer casing 11 of the measuring instrument 10 on the ground or floor surface with one or the other side surface being the lower surface at the time of cleaning. 11, the light emitting unit side lens 27 or the light receiving unit side lens 32 is cleaned with the light emitting unit side lens 27 or the light receiving unit side lens 32 facing upward during cleaning. Therefore, as shown in FIG. 7, the operator visually observes the light emitting unit side lens 27 (or the light receiving unit side lens 32) through the exhaust port 16 in the outer casing 11, and the light emitting unit side lens 27 ( Or light reception The side lens 32) can be wiped off very easily and reliably, and the cleaning result can be easily confirmed. As a result, the detection unit 20 is suitable for the optical system member without being contaminated by the exhaust gas G. Therefore, the desired exhaust gas measurement can be reliably performed with high reliability.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, if the support leg is configured to be able to support the outer casing of the opacimeter in a state where the side surface is the lower surface and always maintaining a stable posture, the specific configuration is as described in the above embodiment. It is not limited to those.
In addition, the detection unit may be a so-called “direct light type” in which the light emitting unit and the light receiving unit are arranged to face each other via the gas flow path, as in the above embodiment. Both of the light receiving portions are provided in one opening of the measurement chamber forming material, and an appropriate reflecting member is provided in the other opening of the measurement chamber forming material so as to form a reflected light path. It may be of “formula” or any of them.

It is a front view which shows the general view in an example of the measuring device which comprises the opacimeter of this invention. It is a rear view of the measuring device shown in FIG. It is a right view of the measuring device shown in FIG. It is explanatory drawing which shows roughly the internal structure of the measuring device shown in FIG. It is explanatory drawing which shows the example of 1 structure of the exhaust-gas measurement system by the opacimeter of this invention. It is explanatory drawing which shows the state at the time of the cleaning of the measuring device shown in FIG. It is a perspective view which expands and shows the exhaust-portion part of the outer casing at the time of cleaning. It is sectional drawing for description which shows the outline of a structure in an example of the measuring device which concerns on the conventional opacimeter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Measuring instrument 11 Outer casing 12 Partition wall 13 Upper chamber 14 Lower chamber 15 Signal processing board 16 Exhaust port 18 Blower fan 20 Detection part 21 Measurement chamber formation material 21A Measurement chamber 22 Gas flow path formation material 22A Gas flow path 25 Light emission part 26 Light source 27 Light emitting part side lens 28 Exhaust gas inlet 30 Light receiving part 31 Light receiving sensor 32 Light receiving part side lens 40 Carrying grip part 41 Air introducing part 42 Power switch 43 Communication connector 44 Power output part 45 Power input part 46 Sampling tube connection Part 48 Sampling tube 50 Support leg 51 Central bent part 52 Leg part 53 Rubber cap 55 Support part 60 Test vehicle 65 Display device 66 Signal transmission cable 70 Detector 71 Gas flow path forming material 72 Gas flow path 72A Gas introduction port 73 Light source 74 Light Emitting Unit 75 Light Detection Sensor 76 Light Receiving Unit 80 Outer casing 81 Exhaust port PA Purge air G Exhaust gas F Floor (or ground)

Claims (1)

Detection to determine the concentration of more particulate matter in the exhaust gas to be detected light emitting portion and a light receiving portion so that the optical path is formed is provided in a measurement chamber where the exhaust gas is introduced, the degree of attenuation of the measurement light part is, in Opashimeta having a measuring device comprising disposed within the cover hood,
In the measuring instrument, on the both sides of the outer casing, the outer casing is opened on the both sides of the outer casing in a state where the exhaust opening opened to the outer casing faces downward and the exhaust outlet is separated from the ground or floor surface. Support legs are provided to support, and the support legs are configured to be able to support the outer casing in a state where one or the other side surface is a lower surface .
The light-emitting unit and the light-receiving unit have a light-transmitting or reflecting optical system member, and the optical system member is positioned in a state exposed to a space following the exhaust port, and one or the other side surface of the outer casing The opacimeter is characterized in that the optical system member is visible through the exhaust port in a state where is the lower surface .