JP7541956B2 - Furnace viewing window - Google Patents

Description

The present invention relates to an incinerator observation window installed in an incinerator.

Examples of this type of technology include the conventional technology described in Patent Documents 1 and 2. The conventional technology is as follows:

In the furnace viewing window device described in Patent Document 1, a first gas supply port for blowing a gas flow toward the furnace interior is provided at the rear side of the viewing window body, and a second gas supply port for blowing a gas flow in a direction intersecting the above-mentioned gas flow is provided at the open tip portion of the viewing window body.
With the above configuration, furnace gas attempting to flow from inside the furnace toward the sight glass is sealed near the opening of the sight glass body by the curtain air blown out from the second gas supply port, thereby preventing the furnace gas from entering the sight glass body.

The sight glass described in Patent Document 2 includes a purge fluid supplying means for supplying purge fluid near a transparent plate inside a cylindrical member, and a cylindrical porous plate for rectifying the flow of the purge fluid supplied from the purge fluid supplying means.
It is said that the above configuration makes it possible to effectively replace the gas inside the cylindrical member and prevent the transparent plate from becoming dirty.

Japanese Unexamined Patent Publication No. 55-79989 JP 2005-90870 A

However, the techniques described in Patent Documents 1 and 2 have the following problems. First, with regard to the technique described in Patent Document 1, the direction of the curtain air is perpendicular to the direction of the furnace gas flowing from inside the furnace toward the observation window. Therefore, in order to seal the furnace gas with this curtain air, a large amount of gas is required as the curtain air.

Next, in the technology described in Patent Document 2, the purge fluid is discharged from the holes in the cylindrical perforated plate into the cylindrical member parallel to the transparent plate. With this configuration, of the purge fluid discharged from the holes in the cylindrical perforated plate, a portion of the purge fluid discharged from the hole closer to the transparent plate flows toward the transparent plate. Therefore, if the cylindrical member is short, gas from inside the device may be caught in the purge fluid heading toward the transparent plate and reach the transparent plate. As a result, the transparent plate becomes contaminated with dust contained in the gas. To prevent gas from inside the device from reaching the transparent plate, it is necessary to either supply a large amount of purge fluid into the cylindrical member or to lengthen the cylindrical member.

The present invention was made in consideration of the above circumstances, and its purpose is to provide a furnace observation window that is configured to prevent gas from inside the furnace from reaching the transparent plate without requiring a large amount of gas to be blown in.

The present invention is a furnace viewing window that is installed in a furnace, and includes a cylindrical member having one end attached to the furnace, and a transparent plate that is attached to the other end of the cylindrical member and allows viewing into the inside of the furnace. This furnace viewing window has a slit-shaped gas supply hole formed in the cylindrical member and extending in a direction intersecting the axial direction of the cylindrical member, and a guide mechanism that guides the gas supplied from the gas supply hole to the inside of the cylindrical member to the inside of the furnace.

According to the present invention, the gas supply holes are slit-shaped extending in a direction intersecting the axial direction, and the above-mentioned guide mechanism can prevent the gas supplied into the cylindrical member from flowing back toward the transparent plate. As a result, it is possible to prevent the gas from inside the furnace from reaching the transparent plate without the need for a large amount of blown-in gas.

FIG. 2 is a cross-sectional plan view of a furnace observation window according to the first embodiment of the present invention. 2 is a view of the furnace observation window as seen along the arrows A-A in FIG. 1 . FIG. 2 is a plan view of a single cylindrical member constituting the furnace observation window shown in FIG. 1 . FIG. 5 is a cross-sectional plan view of a furnace observation window according to a second embodiment of the present invention. FIG. 11 is a cross-sectional plan view of a furnace observation window according to a third embodiment of the present invention. 13 is a plan view of a single cylindrical member showing a modified example of a gas supply hole formed in the cylindrical member. FIG. FIG. 4 is a cross-sectional plan view of a furnace observation window according to a comparative example. 13 is a diagram showing a verification method for verifying the effect of suppressing gas from inside the furnace from reaching the transparent plate. FIG.

The following describes an embodiment of the present invention with reference to the drawings. The furnace observation window of the present invention is installed in, for example, a furnace for incinerating radioactive waste, but the furnace observation window of the present invention may also be installed in an incinerator for a purpose other than the above-mentioned furnace.

First Embodiment
A furnace observation window 101 according to a first embodiment of the present invention will be described with reference to Figures 1 to 3. The furnace observation window 101 includes a cylindrical member 1 having one end attached to a furnace 51, and a transparent plate 2 attached to the other end of the cylindrical member 1 for observing the inside of the furnace 51. Note that, although the end face of the cylindrical member 1 and the inner surface of the furnace 51 are flush with each other in Figure 1 and the like, a part of the cylindrical member 1 may be inserted into the furnace 51.

In this embodiment, the cylindrical member 1 has a rectangular cross-sectional shape perpendicular to the axial direction Z, i.e., a rectangular duct. Note that squares are included in the category of rectangles. The cylindrical member 1 has four rectangular plate members 3, 4, 5, and 6 that are perpendicular to each other.

The plate members 3, 4, 5, and 6 are each formed with slits 3a, 4a, 5a, and 6a as slit-shaped gas supply holes that extend in a direction intersecting the axial direction Z of the cylindrical member 1. In other words, the above-mentioned slit-shaped gas supply holes are formed on all four circumferential faces of the cylindrical member 1. The slits 3a to 6a extend in a direction perpendicular to the axial direction Z of the cylindrical member 1, but may extend in a direction slightly inclined relative to the direction perpendicular to the axial direction Z.

The slits 3a to 6a are formed on the transparent plate 2 side between the furnace 51 and the transparent plate 2, near the transparent plate 2. The slits 3a to 6a are preferably formed from one end to the other end in the width direction W of each plate member 3 to 6 (the width direction W shown in FIG. 1 is the width direction of the plate members 3 and 5). However, when each surface of the cylindrical member 1 is formed from one plate member 3 to 6 in consideration of ease of manufacture, the slits 3a to 6a are formed except for small portions at both ends of each plate member 3 to 6 in the width direction W, as in this embodiment. Even if each surface of the cylindrical member 1 is formed from two plate members, the two plate members can be supported by the flange plate 12 and the box member 14, which will be described later, respectively, so that a slit that is continuous without interruption around the entire circumference of the cylindrical member 1 may be formed in the cylindrical member 1.

A guide plate 7 is disposed inside the cylindrical member 1 as a guide mechanism that guides the gas supplied to the inside of the cylindrical member 1 from each of the slits 3a to 6a to the inside of the furnace 51.

The guide plate 7 in this embodiment is a quadrangular pyramid-shaped guide plate and is composed of four plate members 8, 9, 10, and 11. Each of the plate members 8 to 11 is arranged in a position facing the slits 3a to 6a. The angle is not particularly limited as long as it can guide the gas supplied to the inside of the cylindrical member 1 to the inside of the furnace 51, but it is preferable that each of the plate members 8 to 11 (guide plate 7) is inclined inward with respect to the inner surface of the opposing cylindrical member 1 at an angle α that is greater than 0° and less than 60° in the direction from the transparent plate 2 to the furnace 51. With this configuration, the occurrence of a backflow toward the transparent plate 2 can be further suppressed. In this embodiment, the angle α is set to 45°.

Negative pressure prevention holes 3b, 4b, 5b, and 6b are provided on the transparent plate 2 side of the tip P of the guide plate 7, which is on the inside side of the furnace 51, and on the transparent plate 2 side of the slits 3a to 6a. Each of the negative pressure prevention holes 3b to 6b is formed in each of the plate members 3 to 6 that constitute the cylindrical member 1. In this embodiment, each of the negative pressure prevention holes 3b to 6b is formed in multiples in each of the plate members 3 to 6.

A box member 14 is attached to the outer periphery of the transparent plate 2 side of the cylindrical member 1 through the slits 3a to 6a and the negative pressure prevention holes 3b to 6b to supply (blow) gas into the inside of the cylindrical member 1. The box member 14 is composed of a cylindrical casing 15 and a plate member 16 fixed to the end face of the cylindrical casing 15. A gas supply port 15a is formed in the cylindrical casing 15, and gas from a gas supply means (such as a blower or gas compressor) not shown in the figure is introduced into the box member 14 from the gas supply port 15a, and then supplied into the cylindrical member 1 through each of the slits 3a to 6a and each of the negative pressure prevention holes 3b to 6b. It is preferable that the amount of gas supplied into the cylindrical member 1 from each of the slits 3a to 6a is greater than the amount of gas supplied into the cylindrical member 1 from the corresponding negative pressure prevention holes 3b to 6b. For example, the total opening area of each of the slits 3a to 6a is made larger than the total opening area of each of the negative pressure prevention holes 3b to 6b.

In this embodiment, one gas supply port 15a is formed in the cylindrical casing 15, and gas introduced into the box member 14 from the one gas supply port 15a is supplied into the cylindrical member 1 from each of the slits 3a to 6a and each of the negative pressure prevention holes 3b to 6b, but multiple gas supply ports 15a may be formed. The gas supplied (blown) into the cylindrical member 1 to prevent contamination of the transparent plate 2 is air or an inert gas such as argon gas.

A flange plate 12 is attached to the end face of the cylindrical member 1, and the transparent plate 2 is fixed to the flange plate 12 via a support frame 13. Note that the method of fixing the transparent plate 2 to the cylindrical member 1 is not limited to this. The material of the transparent plate 2 is, for example, heat-resistant glass.

The function of preventing contamination of the transparent plate 2 will now be described. In FIG. 1, the solid arrows in the cylindrical member 1 indicate the flow of gas blown into the cylindrical member 1 from each of the slits 3a to 6a. Strictly speaking, the solid arrows in the cylindrical member 1 indicate the flow of gas blown into the cylindrical member 1 from the slits 4a and 6a. Also, in FIG. 1, the dotted arrows in the cylindrical member 1 between the guide plate 7 and the transparent plate 2 indicate the flow of gas blown into the cylindrical member 1 from each of the negative pressure prevention holes 3b to 6b. Strictly speaking, the dotted arrows in the cylindrical member 1 indicate the flow of gas blown into the cylindrical member 1 from the negative pressure prevention holes 4b and 6b.

When gas is blown into the cylindrical member 1 through each of the slits 3a to 6a, the blown gas is guided to the inside of the furnace 51 by the guide plate 7.

If the slits 3a-6a were not slit-shaped gas supply holes but multiple holes spaced at a given distance from each other, there would be areas between adjacent holes where the pressure would be lower than in the areas near the holes, meaning that non-uniformity in the gas pressure would occur. This could cause a portion of the gas blown into the cylindrical member 1 to flow back toward the transparent plate 2 on the opposite side of the furnace 51.

However, in the furnace viewing window 101 of this embodiment, the gas supply holes are slits 3a to 6a, so that the gas is blown into the cylindrical member 1 in the form of a "surface," so to speak, and this suppresses non-uniformity in the gas pressure at the gas blowing section. Furthermore, the gas blown into the cylindrical member 1 from each of the slits 3a to 6a is guided to the inside of the furnace 51 by the guide plate 7. This makes it possible to suppress the occurrence of the backflow toward the transparent plate 2. As a result, it is possible to prevent gas containing dust from inside the furnace 51 from being caught in the backflow and reaching the transparent plate 2, which would otherwise cause the transparent plate 2 to become dirty.

In addition, in this embodiment, gas is supplied from the negative pressure prevention holes 3b to 6b to the space between the guide plate 7 and the transparent plate 2, which prevents the pressure in the space between the tip P of the guide plate 7 and the transparent plate 2 from becoming lower than the space on the furnace 51 side of the tip P of the guide plate 7. In other words, the space between the tip P of the guide plate 7 and the transparent plate 2 is prevented from becoming negative pressure, and the occurrence of the above-mentioned backflow toward the transparent plate 2 can be further suppressed.

The results of verifying the effectiveness of preventing gas from inside the furnace 51 from reaching the transparent plate 2 are described below. Figure 8 shows the verification method.

The above verification was carried out using the furnace sight glass 101 according to the first embodiment shown in Figures 1 to 3 and the furnace sight glass 150 according to the comparative example shown in Figure 7. The differences between the furnace sight glass 101 according to the first embodiment and the furnace sight glass 150 according to the comparative example shown in Figure 7 are as follows. The furnace sight glass 150 according to the comparative example does not have a guide plate 7 (guide mechanism) and negative pressure prevention holes 3b to 6b. The other configurations of the furnace sight glass 150 are the same as those of the furnace sight glass 101.

As shown in FIG. 8, the electric fan 52 is placed 1.5 m from the tip of the furnace peephole 101 (furnace peephole 150), and the water spraying means 53 is placed 0.5 m from the electric fan 52 toward the furnace peephole 101. Although not shown, one of the four faces of the cylindrical member 1 constituting the furnace peephole is made of a transparent acrylic plate, avoiding slits, etc., so that the inside can be easily visually confirmed from the side. The wind from the electric fan 52 simulates gas from inside the furnace 51, and the sprayed water from the water spraying means 53 simulates dust contained in the gas.

The conditions of the verification experiment are as follows. The cylindrical member 1 constituting each furnace observation window 101, 150 has a size of 100 mm in height x 150 mm in width x 300 mm in length (depth). In addition, the slits 3a, 5a formed on the plate members 3, 5, i.e., the long sides, of the four faces of the cylindrical member 1, have a size of 4 mm in width x 140 mm in length. The slits 4a, 6a formed on the plate members 4, 6, i.e., the short sides, have a size of 4 mm in width x 90 mm in length.

The negative pressure prevention holes 3b, 5b formed in the plate members 3, 5 of the four sides of the cylindrical member 1 of the furnace viewing window 101 are each φ5×6. The negative pressure prevention holes 4b, 6b formed in the plate members 4, 6 of the cylindrical member 1 of the furnace viewing window 101 are each φ5×4. The total opening area of each of the slits 3a-6a is four times the total opening area of each of the negative pressure prevention holes 3b-6b.

The air flow rate blown into the cylindrical member 1 from the gas supply port 15a of each of the furnace observation windows 101 and 150 was changed in four stages: 30.2 ^m3 /h, ^{55.3 m3} /h, 69.9 ^m3 /h, and 77.4 ^m3 /h. The wind speed from the electric fan 52 to each of the furnace observation windows 101 and 150 was 3.7 m/s when it left the electric fan 52 (actual measurement). The particle size of the sprayed water sprayed from the tip of the water spraying means 53 was 130 μm. The speed of the sprayed water at the tip of each of the furnace observation windows 101 and 150 was 3.1 m/s (calculated value).

The results of the verification experiment are as follows. First, in the furnace viewing window 150 according to the comparative example, in all cases where the air flow rate blown into the cylindrical member 1 from the gas supply port 15a was changed in four stages, the sprayed water carried by the wind from the electric fan 52 entered the cylindrical member 1 and adhered to the transparent plate 2 as water droplets. Note that the air flow appeared to be stable at the outlet of the furnace viewing window 150 (the outlet for the air blown in from the gas supply port 15a), but as described above, the sprayed water carried by the wind from the electric fan 52 adhered to the transparent plate 2 as water droplets. In other words, there is a high possibility that the air flow is turbulent inside the cylindrical member 1.

Even with the furnace viewing window 150, it is expected that spray water can be prevented from adhering to the transparent plate 2 by blowing a large amount of gas into the cylindrical member 1 through the slit from the gas supply port 15a.

In contrast, in the furnace viewing window 101 according to the first embodiment of the present invention, the sprayed water did not adhere to the transparent plate 2 in all cases where the air flow rate blown into the cylindrical member 1 from the gas supply port 15a was changed in four stages. It was confirmed that the sprayed water carried by the wind from the electric fan 52 entered the cylindrical member 1, but the sprayed water was blocked by the air flow blown in from the supply port 15a in front of the guide plate 7 and did not penetrate any further. This verification experiment shows that the furnace viewing window 101 can prevent the transparent plate 2 from becoming dirty with dust-containing gas from inside the furnace 51 without the need for a large amount of blown gas.

Second Embodiment
4 shows a furnace observation window 102 according to a second embodiment of the present invention. The differences from the furnace observation window 101 of the first embodiment are as follows. Note that, with respect to the furnace observation window 102 according to the second embodiment, the same members as those of the furnace observation window 101 of the first embodiment are denoted by the same reference numerals (the same applies to the other embodiments).

In the furnace viewing window 101 of the first embodiment, the negative pressure prevention holes 3b to 6b are formed in the cylindrical member 1. In contrast to this, in the furnace viewing window 102 of this embodiment, the negative pressure prevention hole 10a is formed in the guide plate 7. Note that while FIG. 4 only shows the negative pressure prevention hole 10a formed in the plate member 10 constituting the guide plate 7, it is preferable that negative pressure prevention holes are also formed in the remaining plate members 8, 9, and 11 (see FIG. 2) constituting the guide plate 7.

With this configuration, like the furnace peephole 101 of the first embodiment in which a negative pressure prevention hole is provided in the cylindrical member 1, it is possible to prevent the space between the tip P of the guide plate 7 and the transparent plate 2 from becoming negative pressure.

In this way, the position of the negative pressure prevention hole may be closer to the transparent plate 2 than the tip P of the guide plate 7 (guide mechanism), and the negative pressure prevention hole 10a may be formed in the guide plate 7 instead of the cylindrical member 1 as described above. Note that, as in the furnace observation window 101 of the first embodiment, it is preferable to form the negative pressure prevention holes 3b to 6b in the cylindrical member 1 and supply gas to the inside of the cylindrical member 1 from the negative pressure prevention holes 3b to 6b, since this can forcibly prevent the space between the guide plate 7 and the transparent plate 2 from becoming negative pressure. In addition, since the gas from the gas supply means (blower, gas compressor, etc.) not shown in the figure is generally clean, the gas is blown between the guide plate 7 and the transparent plate 2 through the negative pressure prevention holes 3b to 6b to obtain a preliminary cleaning effect of the transparent plate 2, and it is possible to further prevent the transparent plate 2 from becoming dirty with gas containing dust from inside the furnace 51.

Third Embodiment
5 shows a furnace observation window 103 according to a third embodiment of the present invention. The differences from the furnace observation window 101 of the first embodiment are as follows.

The furnace viewing window 103 of this embodiment does not have the guide plate 7 that the furnace viewing window 101 of the first embodiment has. In this embodiment, as shown in FIG. 5 for slits 4a and 6a, the depth of the slits 3a to 6a as gas supply holes is made longer than the slits 3a to 6a in the first embodiment, so that each of the slits 3a to 6a itself serves as a guide mechanism that guides gas to the inside of the furnace 51. In other words, in this embodiment, the slit-shaped gas supply hole and the guide mechanism that guides gas to the inside of the furnace 51 are integrated.

Specifically, as shown in FIG. 5, for example, in order to increase the thickness of the portion of the cylindrical member 1 adjacent to the transparent plate 2, a plate member 17 of a predetermined thickness is fixed to all four outer surfaces of the cylindrical member 1. Then, the cylindrical member 1 and the plate member 17 are drilled together to form deep slits 3a-6a. Note that although there are no particular limitations on the angle as long as it is an angle that can guide the gas supplied to the inside of the cylindrical member 1 to the inside of the furnace 51, it is preferable that each of the slits 3a-6a is inclined inward with respect to the inner surface of the cylindrical member 1 at an angle β that is greater than 0° and is not greater than 60° in the direction from the transparent plate 2 to the furnace 51. In this embodiment, the angle β is 45°.

As a simpler structure, if the tubular member 1 has a certain thickness, a plate member 17 may be fixed to the outer peripheral surface of the tubular member 1 as in this embodiment, without locally increasing the thickness of the tubular member 1, and a slit may be formed in the tubular member 1 that is oblique to the axial direction Z, and the gas supplied from the slit to the inside of the tubular member 1 may be guided to the inside of the furnace 51.

However, by arranging a guide plate 7 inside the cylindrical member 1, as in the first and second embodiments, the gas supplied to the inside of the cylindrical member 1 can be guided more reliably to the inside of the furnace 51.

In this embodiment, as shown in FIG. 5, the tip of the guide mechanism is the tip P of each of the slits 3a to 6a on the furnace 51 side, and the negative pressure prevention holes 3b to 6b are located on the transparent plate 2 side of the tip of the guide mechanism.

(Modification of slit)
Fig. 6 shows a modified example of a slit-shaped gas supply hole. As shown in Fig. 6, instead of a long and narrow rectangular hole such as the slit 3a shown in Fig. 3, a plurality of closely adjacent holes 18 may be formed in a line in the cylindrical member 1, and these closely adjacent holes 18 may be used as slit-shaped gas supply holes.

The above describes an embodiment of the present invention. However, various other modifications may be made within the scope of what a person skilled in the art can imagine.

For example, the tubular member 1 may be a cylindrical member. Similarly, the transparent plate 2 may be circular, etc.

The negative pressure prevention hole provided on the transparent plate 2 side of the tip of the guide mechanism, which is inside the furnace 51, is not essential.

1: Cylindrical member 2: Transparent plate 3a, 4a, 5a, 6a: Slits (slit-shaped gas supply holes)
3b, 4b, 5b, 6b, 10a: Negative pressure prevention hole 7: Guide plate (guide mechanism)
51: Furnace 101, 102, 103: Furnace observation window

Claims (6)

A furnace observation window installed in a furnace,
A cylindrical member having one end attached to the furnace;
a transparent plate attached to the other end of the cylindrical member for viewing the inside of the furnace;
Equipped with
a slit-shaped gas supply hole formed in the cylindrical member and extending in a direction intersecting with an axial direction of the cylindrical member;
a guide mechanism for guiding the gas supplied from the gas supply hole into the cylindrical member to the inside of the furnace;
a negative pressure prevention hole provided on the transparent plate side of the tip of the guide mechanism, the tip being on the inside of the furnace;
having
A furnace observation window , wherein a total opening area of the gas supply holes is larger than a total opening area of the negative pressure prevention holes. In the furnace observation window according to claim 1 ,
The negative pressure prevention hole is formed in the cylindrical member,
A furnace observation window through which gas is supplied to the inside of the cylindrical member from the negative pressure prevention hole. In the furnace observation window according to any one of claims 1 to 2 ,
The furnace observation window, wherein the guide mechanism is a guide plate arranged inside the cylindrical member. In the furnace observation window according to claim 3 ,
The guide plate is inclined inwardly with respect to the inner surface of the opposing cylindrical member at an angle exceeding 0° and not exceeding 60° in a direction from the transparent plate to the furnace. In the furnace observation window according to any one of claims 1 to 4 ,
The cylindrical member has a rectangular cross section perpendicular to the axial direction,
The gas supply holes are formed on all four circumferential surfaces of the cylindrical member. In the furnace observation window according to claim 5,
the guide mechanism is disposed inside the cylindrical member and has a quadrangular pyramid shape constituted by four plate members,
The four plate members are arranged at positions facing the gas supply holes, respectively, to form furnace observation windows.

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