JP4570038B2 - Dust measuring device - Google Patents

Description

  The present invention relates to a dust measuring device for measuring the concentration of dust contained in a gas flow flowing in a pipe.

  Conventionally, as a dust measuring device for measuring the concentration of dust contained in a gas (for example, city gas, LP gas, etc.) flowing in a pipe (for example, a gas pipe), a light emitting means for emitting measurement light , An irradiating unit for irradiating the measurement light from the light emitting source toward the measurement region, a light receiving unit for receiving the detected light from the measurement region, and a light receiving means for converting the detected light from the light receiving unit into a measurement signal The irradiation unit and the light receiving unit are provided in a detection unit inserted into the pipe, and the irradiation unit of the detection unit and the light emitting means are connected by a first optical fiber, and the light reception unit of the detection unit And the light receiving means are connected by a second optical fiber (see, for example, Patent Document 1).

  In such a measuring apparatus, the measurement light from the light emitting means is guided to the irradiation unit through the first optical fiber, and is irradiated from the irradiation unit toward the measurement area. Further, the detected light from the measurement area is received by the light receiving unit and guided to the light receiving means through the second optical fiber. The light receiving means converts the light to be measured into a measurement signal, the dust concentration is calculated based on the measurement signal, and the concentration of the dust contained in the gas flow flowing through the measurement area is measured in this way.

JP 2004-205217 A

However, the dust measuring apparatus described above has the following problems to be solved. That is, when the detector unit is inserted into the pipe, the pressure in the pipe acts on the detector unit and the like, and when a flexible tube is used as a protective tube for protecting the first and second optical fibers, Due to the difference between the pressure of the tube and the pressure inside the protective tube, the protective tube is easily bent when inserted into the pipe.

An object of the present invention is to provide a dust measuring device that is not easily affected by pressure in a pipe into which a detection unit is inserted.

In the dust measuring apparatus according to claim 1 of the present invention, a light emitting means for emitting measurement light for measuring dust concentration in the measurement area, and a light receiving means for converting the detected light from the measurement area into a measurement signal, A detector unit having an irradiating unit for irradiating the measuring light from the light emitting unit toward the measuring region and a light receiving unit for receiving the detected light from the measuring region, and the measuring light from the light emitting unit A first optical fiber for transmitting to the light receiving portion, a second optical fiber for transmitting the detected light from the light receiving portion to the light receiving means, a protective tube covering the first and second optical fibers, A dust measuring device comprising:
The protective tube includes a flexible tube and a pipe pipe connected to each other, the detection unit is attached to a distal end portion of the flexible tube, and the first and second optical fibers pass through the flexible tube and the pipe pipe. The flexible tube is guided to the light emitting means and the light receiving means and communicates with the outside.

In the dust measuring apparatus according to claim 2 of the present invention, the pipe pipe includes a pipe main body and an end wall provided at one end of the pipe main body, and the flexible tube is connected to the end wall. The first and second optical fibers extend into the pipe body through the end wall portion, and pressure in the flexible tube acts on the end wall portion of the pipe tube.

According to the dust measuring apparatus of the first aspect of the present invention , the protective tube covering the first and second optical fibers is composed of the mutually connected flexible tube and pipe tube, and is detected at the tip of the flexible tube. Since the inside of this flexible tube is connected to the outside, when the detector unit is inserted into the pipe, the pressure inside the pipe and the inside of the flexible tube are maintained at the same pressure, and the pressure inside the pipe is flexible. The detector unit can be easily inserted into the piping without affecting the tube. In addition, in a state where the detection unit is inserted into the pipe through the insertion pipe, for example, the pipe pipe comes to be positioned at the insertion section of the insertion pipe, so that the gap between the insertion pipe and the pipe pipe can be reliably sealed. The leakage of the gas flow in the pipe to the outside can be prevented.

According to the dust measuring apparatus of the second aspect of the present invention, the pipe pipe has a pipe main body and an end wall provided at one end of the pipe main body, and the flexible tube is attached to the end wall. Since it is connected, the pressure in the flexible tube acts on the end wall portion of the pipe tube, and this pressure can be received by the tube body via the end wall portion.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an exemplary embodiment of a dust measuring device according to the invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view schematically showing an example of a piping structure for measuring dust concentration using the dust measuring device of one embodiment, and FIG. 2 is a front view showing a detection unit of the dust measuring device of FIG. 3 is a side view showing the detection unit of FIG. 2, FIG. 4 is a bottom view showing the detection unit of FIG. 2, and FIG. 5 is taken along line VV in FIG. FIG. 6 is a cross-sectional view, and FIG. 6 is a cross-sectional view showing a state when the detection unit of FIG. 2 is inserted through a curved pipe.

  In FIG. 1, the illustrated dust measuring device 2 includes dust contained in a gas (for example, city gas, LP gas, etc.) flowing in a fluid flow path 8 defined by a piping 6 of the fluid piping structure 4, for example, a gas piping. Used to measure the concentration of dust. The dust measurement device 2 includes a detection unit 10 and a flexible tube 12 attached to the base side of the detection unit 10, and the flexible tube 12 is connected to the measurement device main body 14. In the illustrated example, a main opening / closing valve 16 is disposed at a predetermined portion of the pipe 6 of the fluid piping structure 4, and diffusion pipes 18, 20 are disposed upstream and downstream of the main opening / closing valve 16. One ends of the pipes 18 and 20 are connected to the pipe 6, and open / close ball valves 22 and 24 are provided at the other ends thereof. The diffusion tubes 18 and 20 function as an insertion tube for inserting the detection unit 10, and the detection unit 10 is inserted into the measurement area 26 in the pipe 6 through the diffusion tube 18 (or 20) as will be described later. The

  2 to 5, the detection unit 10 includes a detection unit main body 28, and the detection unit main body 28 is attached to one end (front end) of the flexible tube 12. The detection unit main body 28 has a substantially columnar main body 29 and an extension 31 that extends from the main body 29 in a substantially quadrangular prism shape. The front end of the extension 31 is on the front side (in front of the page in FIG. 2). A protrusion 33 is provided which protrudes to the right side in FIG. 3 and FIG. A recess 30 is provided in the middle of the detection body 28 in the axial direction (vertical direction in FIGS. 2, 3, and 5), that is, between the body 29 and the protrusion 33 of the extension 31. The irradiation unit 32 is provided on one end side (upper side in FIGS. 2, 3 and 5), and the light receiving unit 34 is provided on the other end side (lower side in FIGS. 2, 3 and 5) of the recess 30. The irradiation unit 32 and the light receiving unit 34 are arranged so as to face each other. The irradiation unit 32 is provided with an irradiation port 36, and an irradiation cover 37 is attached so as to seal the irradiation port 36, and the light receiving unit 34 is provided with a light receiving port 38, so that the light receiving port 38 is sealed. A light receiving cover 40 is provided.

  The detection unit body 28 is further provided with a first passage 42 communicating with the irradiation port 36 and a second passage 44 communicating with the light receiving port 38. In this embodiment, the first passage 42 extends linearly with the main body portion 29 facing the irradiation port 36, and the second passage 44 linearly extends the main body portion 29 and the extension portion 31 substantially parallel to the first passage 42. After extending in a straight line, the extension 31 is bent toward the light receiving port 38 to extend in a straight line. In relation to this, a reflecting mirror 46 is disposed at the bent portion of the second passage 44. The reflecting mirror 46 is attached to the distal end cover 48, and the reflecting mirror 46 is attached to the detection unit main body 28 by attaching the distal end cover 48 to the distal end portion of the extension portion 31.

  Measurement light from the first optical fiber 50 is guided to the irradiation unit 32 of the detection unit 10. The first optical fiber 50 is composed of a fiber 52 that transmits measurement light as will be described later, and a protective coating 54 that covers the fiber 52, and at one end side (tip side), the distal end of the fiber 52 that protrudes from the protective coating 54. Is inserted into the first passage 42 of the detector main body 28 and positioned. Further, the detection light from the light receiving unit 34 is configured to be guided to the second optical fiber 56. Similar to the first optical fiber 50, the second optical fiber 56 includes a fiber 58 and a protective coating 60 that covers the fiber 58, and at one end side (tip side), the distal end portion of the fiber 58 that protrudes from the protective coating 60. Is inserted into the second passage 44 of the detector main body 28 and positioned. Accordingly, the measurement light transmitted from the measurement apparatus main body 14 through the first optical fiber 50 is irradiated from the irradiation unit 32 toward the measurement area 26 through the irradiation cover 37, and the detected light from the measurement area 26, that is, the measurement area. The light scattered by the dust at 26 is received by the light receiving unit 34 through the light receiving cover 40, and the detected light thus received is reflected by the reflecting mirror 46 and then guided to the second optical fiber 56. And transmitted to the measuring apparatus main body 14.

  In relation to the irradiation unit 32 and the light receiving unit 34 of the detection unit 28, the following configuration is desirable. That is, it is desirable to set the scattering angle α between the optical axis 55 of the irradiation unit 32 and the optical axis 57 of the light receiving unit 34 within an angle range of 120 to 135 degrees, for example, 130 degrees. By setting the value within the range, the scattered light of the dust in the measurement area 26 is efficiently received by the light receiving unit 34, and the S / N of the measurement signal when measuring the dust concentration can be increased, and the dust concentration can be accurately set. It becomes possible to measure. In order to set the scattering angle α in such an angle range, in this embodiment, the central axis of the irradiation portion 32 side opening of the first passage 42 and the central axis of the light receiving portion 34 side opening of the second passage 44 are arranged. Is set to be, for example, 130 degrees within an angle range of 120 to 135 degrees.

  Further, while maintaining the scattering angle α in the above-described angle range, the optical axis 55 of the irradiation unit 32 is further inclined within an angle range of 5 to 20 degrees (for example, about 10 degrees) with respect to the central axis of the detection unit. Desirably, by setting within such an angle range, it is possible to suppress an increase in the outer shape of the detection unit 28, particularly in the radial direction, and even when the inner diameter of the insertion tube is small. The detection unit 28 can be inserted. Specifically, the central axis of the first passage 42 may be set within an angle range of 5 to 20 degrees with respect to the central axis of the detection unit 28. At this time, the second optical fiber 56 of the second passage 44 is used. The central axis of the side portion is formed so as to be substantially parallel to the central axis of the detection unit 28.

  The first and second optical fibers 50 and 56 are built in the flexible tube 12. The flexible tube 12 includes a flexible flexible tube 62 formed of, for example, stainless steel and a protective tube 64 that covers the flexible tube 62. The first and second optical fibers 50 and 56 are formed of the flexible tube. 62 extends. A connecting tool (not shown) is provided at the other end portion of the flexible tube 12, and the connecting portion is detachably attached to the connecting portion 65 of the measuring device main body 14 to be connected to the measuring device main body 14. .

  The measurement apparatus main body 14 includes a light emitting means 66 (for example, composed of a laser light emitting element) that emits measurement light, and a light receiving means 68 (for example, a light receiving element such as a CCD) that receives the light to be measured and converts it into a measurement signal. And a dust concentration calculating means 70 including a microprocessor or the like. The first optical fiber 50 is connected to the light emitting means 66 via the connector 65, the second optical fiber 56 is connected to the light receiving means 68 via the connector 65, and the measurement light from the light emitting means 66 is transmitted to the first optical fiber. 50, and the detected light from the second optical fiber 56 is sent to the light receiving means 68. The light receiving means 68 generates a measurement signal having a level corresponding to the amount of light to be measured, and the dust concentration calculating means 70 calculates the dust concentration based on the measurement signal, and the calculated dust concentration is displayed on the display means 72 (for example, liquid crystal). Display device).

  A light shielding member 74 is provided in the recess 30 of the detection unit 10. The light blocking member 74 prevents the measurement light from the irradiation unit 32 from being directly received by the light receiving unit 34. Further, a notch portion 76 is provided on the front side portion of the main body portion 29 of the detection unit 10 so that reflected light from the main body portion 29 is not received by the light receiving portion 34.

  The detection unit 10 is further configured as follows. Both side portions of the detection unit 10 are narrowed toward the distal end side (downward in FIGS. 2, 3 and 5) (see particularly FIG. 2). In this configuration, the main body portion 29 is tapered from the distal end portion to the base portion of the extension portion 31. By such a taper configuration, the detection unit unit 10 can be easily inserted through an insertion tube (described later). At the same time, when the detection unit 10 is inserted into the pipe 6, the gas flow flowing in the direction indicated by the arrow 78 in the pipe 6 is this fine detail (the part where the irradiation unit 32 and the light receiving unit 34 are provided). In FIG. 2, both sides, that is, both sides of the extension 31 flow smoothly, and the occurrence of turbulence in the measurement area 26 can be suppressed.

  In addition, the outer shape of the detection unit 10 is such that the main body 29 is formed in a substantially cylindrical shape, and an extension 31 extending from the main body 29 is formed in a substantially quadrangular prism shape. ), The extension portion 31 is smaller than the main body portion 29, so that the detection unit unit 10 as a whole becomes thinner toward the distal end side. Thus, by thinning the entire outer shape toward the distal end side, the detector unit 10 can be more easily inserted into an insertion tube (described later), and a bent tube (so-called curved tube) can be used. Even if it exists, it becomes possible to insert easily.

  The measurement of the dust concentration of the gas flowing through the pipe 4 is performed as follows, for example. First, as shown in FIG. 1, an introduction pipe (not shown) is detachably attached to an open / close ball valve 22 connected to a diffusion pipe 18 to be inserted (functions as an insertion pipe), and the inside of the introduction hole of the introduction pipe is inserted. Then, the detecting unit 10 is inserted and held, and the open / close ball valve 22 is opened to be introduced through the introduction hole of the introduction pipe and the open / close ball valve 22 in the insertion direction indicated by the arrow 80 (see FIG. 1). In this embodiment, the diffusion tube 18 is bent downward after being bent to the right in FIG. 1, but the detection unit 10 of the dust measuring device 2 is attached to the distal end portion of the flexible tube 12, and the flexible tube 12 itself is Since it has flexibility, as the detection unit 10 is inserted, the flexible tube 12 bends along the shape of the diffusion tube 18 and is bent so that the detection unit 10 is piped through the diffusion tube 18. 6 fluid flow paths 8 can be inserted.

  At the time of this insertion, the entire shape of the detection unit 10 is narrowed toward the distal end side. Therefore, when the distal end of the detection unit 10 reaches the bent portion 82 of the diffusion tube 18, as shown in FIG. Further, the tip of the detection unit 10, that is, the tip of the extension 31 contacts the inner peripheral surface of the curved portion 82, and as shown by a two-dot chain line in FIG. Therefore, even if the diffusion pipe 18 is bent, it can be easily inserted into the measurement area 26 of the pipe 6 through the diffusion pipe 18. In the illustrated embodiment, the cross-sectional shape of the extension portion 31 is formed in a quadrilateral shape, but it may be a polygonal shape such as a hexagonal shape or an octagonal shape. Similar effects can be achieved.

  When measuring the concentration of dust contained in the gas flow flowing through the pipe 6, the measurement light from the light emitting means 66 is transmitted to the irradiation unit 32 through the first optical fiber 50, and the irradiation unit 32 toward the measurement region 26. Irradiated. Then, the detected light from the measurement area 26 is received by the light receiving unit 34, reflected by the reflecting mirror 46, and then transmitted to the light receiving means 68 through the second optical fiber 56. The light receiving means 68 generates a measurement signal corresponding to the light to be detected, the dust concentration calculating means 70 calculates the dust concentration based on the measurement signal, and the calculated dust concentration is displayed on the display means 72. Thus, the concentration of dust contained in the gas flow in the pipe 6 is measured.

  In this embodiment, since the detection unit 10 is attached to the distal end of the flexible tube 12, there is a possibility that the pressure in the pipe 6 acts on the flexible tube 12 and bends when inserted through the diffusion tube 18. When the flexible tube 12 is bent, it becomes difficult to insert the detection unit 10 through the diffusion tube 18, but in order to solve such a problem, it is desirable to configure as shown in FIG. FIG. 7 is a cross-sectional view showing a part of the modified protection tube cut out. The same members as those in the embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted. .

  The protective tube in this modified embodiment is composed of a flexible tube 12A and a pipe tube 90 extending linearly. The pipe tube 90 includes a pipe main body 92 and an end wall portion 94 provided at the distal end portion of the pipe main body 92, and itself has sufficient rigidity. A connecting tool 96 is attached to the end wall portion 94 of the pipe tube 90 by means such as welding, and the flexible tube 12 </ b> A is connected to the connecting tool 96. The flexible tube 12A includes a flexible tube 62 having flexibility and a protective tube 64 that covers the flexible tube 62. The connection tool 96 includes, for example, a cylindrical connection member 98. The flexible tube 12 </ b> A and the pipe tube 90 are connected via the connector 96 by being inserted into the connection member 98 and subjected to caulking, for example. A detection unit similar to that described above is attached to the tip of the flexible tube 12A connected to the pipe 90.

  This protective tube is configured such that the flexible tube 12A, that is, the inside of the flexible tube 62 communicates with the outside. For example, a communication hole (not shown) is provided in a connection portion between the flexible tube 12A and the detection unit (see FIGS. 2 to 5), and the inside of the flexible tube 62 communicates with the outside through this communication hole. Instead of such a communication hole, a through hole may be provided at a predetermined portion of the flexible tube 12A.

  Further, the first and second optical fibers 50 and 56 extending from the measuring device main body (see FIG. 1) extend to the detection unit through the pipe tube 90 and the flexible tube 12A, and the end wall portion 94 of the pipe tube 90 has this end. The first optical fiber 50 extends through the wall portion 94 and is sealed between the first and second optical fibers 50 and 56 and the end wall portion 94. The first optical fiber 50 is an irradiation unit of the detection unit (see FIG. 5). The second optical fiber 56 transmits the detected light from the light receiving unit (see FIG. 5) of the detection unit to the measurement apparatus main body.

  When such a protective tube is used, when the detection unit is inserted through the introduction pipe (not shown), the open / close ball valve 22 and the diffusion pipe 18, the inside of the flexible tube 12A communicates with the outside. And the pressure in the flexible tube 12 </ b> A become equal, and the pressure in the pipe acts on the end wall portion 94 of the pipe tube 90, and receives pressure at the end wall portion 94. Accordingly, the flexible tube 12A is not bent by the pressure in the pipe, and the detection unit can be easily inserted into the pipe. In addition, in a state where the detection unit is inserted into the pipe through the diffusion pipe 18, the pipe pipe 90 is positioned in the introduction pipe, and by configuring in this way, the gap between the pipe pipe 90 and the introduction pipe is set. Sealing can be performed reliably, and gas leakage in the piping during dust measurement can be reliably prevented.

  As mentioned above, although one embodiment of the dust measuring apparatus according to the present invention has been described, the present invention is not limited to such an embodiment, and various changes and modifications can be made without departing from the scope of the present invention.

Sectional drawing which shows simply an example of the piping structure which measures a dust density | concentration using the dust measuring apparatus of one Embodiment. The front view which shows the detection part unit of the dust measuring apparatus of FIG. The side view which shows the detection part unit of FIG. The bottom view which shows the detection part unit of FIG. Sectional drawing by the VV line in FIG. Sectional drawing which shows a state when inserting the detection part unit of FIG. 2 through a curved pipe. Sectional drawing which notches and shows a part of protective tube of a deformation | transformation form.

Explanation of symbols

2 Dust Measuring Device 6 Piping 10 Detector Unit 12, 12A Flexible Tube 14 Measuring Device Body 16 Main Open / Close Valve 18, 20 Radiation Tube (Insertion Tube)
28 Detection unit body 32 Irradiation unit
34 light receiving unit 50 first optical fiber 56 second optical fiber 66 light emitting means 68 light receiving means 74 dust concentration calculating means 90 pipe pipe

Claims (2)

Light emitting means for emitting measurement light for measuring dust concentration in the measurement area, light receiving means for converting detected light from the measurement area into a measurement signal, and directing measurement light from the light emitting means to the measurement area A detector unit having an irradiating unit for irradiating and a light receiving unit for receiving detected light from the measurement area, a first optical fiber for transmitting the measuring light from the light emitting means to the irradiating unit, and the light receiving unit A dust measuring device comprising: a second optical fiber for transmitting detected light from a section to the light receiving means; and a protective tube covering the first and second optical fibers,
The protective tube includes a flexible tube and a pipe pipe connected to each other, the detection unit is attached to a distal end portion of the flexible tube, and the first and second optical fibers pass through the flexible tube and the pipe pipe. A dust measuring apparatus, wherein the dust tube is guided to the light emitting means and the light receiving means, and the inside of the flexible tube communicates with the outside. The pipe pipe includes a pipe main body and an end wall provided at one end of the pipe main body, the flexible tube is connected to the end wall, and the first and second optical fibers pass through the end wall. The dust measuring device according to claim 1 , wherein the dust measuring device extends into the pipe body, and pressure in the flexible tube acts on the end wall portion of the pipe tube.

Images