JP5521428B2 - Reaction vessel for manufacturing glass particulate deposits - Google Patents

Description

  The present invention relates to a reaction vessel in which glass particles are sprayed and deposited on a target with an oxyhydrogen flame, and is particularly suitable for use in the production of an optical fiber glass preform with little contamination by foreign matter.

  In the manufacture of glass products such as optical fiber preforms, a glass particle synthesis burner is placed facing the target in the reaction vessel, and glass particles are deposited on the surface of the target in layers (sooted). Obtain a solid body (soot body). An exhaust device that discharges excess soot is connected to the reaction vessel. The reaction vessel is formed in, for example, a rectangular parallelepiped shape, has a metal furnace body with a heat-resistant temperature of 200 to 300 ° C., and is used for attaching a starting rod, cleaning the inside, etc. on one side (opening surface) of the operator side Having an opening. A square frame-shaped mating surface is formed around the opening on the opening surface. A door is openably / closably attached to the furnace body via a hinge, and the door covers the opening and seals the opening. That is, the mating surface around the opening and the mating surface of the door are brought into an airtight state.

FIG. 5A is a cross-sectional view of the conventional reaction vessel when the opening surface is opened, and FIG. 5B is a cross-sectional view when the opening surface is sealed.
As shown in FIG. 5 (a), the opening structure 505 of the furnace body 503 whose inner surface is covered with a metal (for example, nickel) partition wall 501 is formed by a hinge (not shown). It is opened and closed by a door 507 that is rotatably supported. A plurality of clamp members 509 are provided around the opening surface 505. The clamp member 509 includes a bracket 511 fixed to the furnace body 503, a support shaft 513 supported by the bracket 511, a swing shaft 515 that is rotatably supported by the support shaft 513, and a swing shaft. The clamp handle 517 is screwed onto the shaft 515.

  In the above sealing structure, in order to seal the opening surface 505 of the furnace body 503, as shown in FIG. 5B, the door 507 is closed, and the swing shaft 515 is attached to the furnace body 503 and the frame members 519 and 521 of the door 507. The opening 505 is sealed in an airtight state by entering the receiving portions 523 and 525 that are notched in the direction and rotating the clamp handle 517 in the tightening direction.

JP 2000-169174 A

  However, since the door 507 has a high heat of about 200 to 300 ° C., a slight gap is generated due to distortion of the member due to heat, and the airtightness cannot be sufficiently improved. In addition, since the inside of the furnace body 503 to which the exhaust device is connected has a slight negative pressure, foreign matter floating outside the reaction container is caused by the gap between the doors 507 (the mating surfaces 527 and 529 between the furnace body 503 and the door 507). It enters the reaction vessel through the gap between the two and adheres to the soot body. When foreign matter enters or adheres to the inside or surface of the soot body at the time of sooting, it may cause bubbles when vitrified, causing a problem of inducing breakage during drawing and reducing yield. In order to seal the reaction vessel, for example, it is desirable to provide a sealing material on the door 507 as disclosed in Patent Document 1. However, since the door 507 is at a high temperature, the sealing material is resistant to high temperatures and has flexibility. It was difficult to find. In addition, the development of a new sealed structure that can maintain the sealing performance while absorbing not only the material performance of the sealing material but also distortion at the time of high-temperature deformation has been desired.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a reaction vessel for producing a glass particulate deposit body that can improve the sealing performance of a furnace body and a door and prevent the entry of foreign matter, and thus for an optical fiber. The object is to reduce the contamination of foreign substances in the glass base material.

The above object of the present invention is achieved by the following configuration.
(1) A furnace body having a burner that internally burns and deposits glass particles on a target by an oxyhydrogen flame, and a door that covers an opening surface on the operator side of the furnace body, and a mating surface of the furnace body and the door A reaction vessel for producing a glass particulate deposit, wherein the first sealing material is provided with
A second sealing material having heat resistance attached to the end portion so as to cover the end portion of the mating surface from the outside on the outer periphery perpendicular to the mating surface ,
The second sealing material is disposed on the inner surface of the frame installed so as to cover the end of the mating surface from the outside,
A plurality of U-shaped cross sections for holding the door in a closed state, sandwiching the end of the furnace body and the end of the door, and pressing the frame against the mating surface, outside the frame A reaction container for producing a glass particulate deposit, wherein a clamp member is provided .

  According to this reaction vessel for producing a fine glass particle deposit, the mating surface of the furnace body and the door is closed with the first sealing material, and the previous gap can be closed (airtight seal), and the mating surface is exposed. Further, the second sealing material is pressed against the outer periphery of the door, and the subsequent gap is closed. Thereby, the clearance gap between a furnace body and a door is block | closed with a multistage structure, and airtightness improves. Since the heat insulation effect is obtained by the first sealing material in the front gap closing portion, the rear gap closing portion is at a lower temperature than the front gap closing portion. Since the downstream gap closing portion can be made at a relatively low temperature, the options for the sealing material can be expanded, and contamination with foreign matter into the furnace body is surely prevented.

Further, according to this reaction container for producing a glass particle deposit, the peripheral edge of the opening formed in the furnace body and the peripheral edge of the door overlap in a closed state, and the end of the mating surface of these peripheral edges is the second. It is closed with a sealing material. The second sealing member is disposed on the inner surface of the frame installed so as to cover the mating surface, and a plurality of clamp members are provided on the outer side to fix the door in a closed state. The clamp member has a U-shaped cross section, and the clamp member fixes the furnace body end portion and the door end portion by sandwiching and clamping. Further, by tightening with the clamp member, the mating surface exposed to the peripheral edge of the opening is pressed against the second sealing material disposed on the inner surface of the frame, and is further sealed and closed.

( 2 ) A reaction vessel for producing a glass particulate deposit according to ( 1) ,
The second sealing material is a silicon rubber sponge, a reaction container for producing a fine glass particle deposit.

  According to this reaction container for producing a fine glass particle deposit, the second sealing material is a silicon rubber sponge, which is excellent in heat resistance, wear resistance, heat insulation, and rebound resilience, and at a high temperature of about 200 ° C. However, the displacement of the mating surface due to thermal expansion can be absorbed by the cushioning property, and the sealed structure can be maintained.

  According to the reaction vessel for producing a glass particulate deposit according to the present invention, in the reaction vessel for producing a glass particulate deposit, the first sealing material is provided on the mating surface between the furnace and the door. Since the second sealing material having heat resistance is attached to the outer periphery so as to cover the end portion of the mating surface from the outside in the outer periphery perpendicular to the surface, the sealing performance of the furnace body and the door can be improved. It is possible to prevent foreign matter from entering. As a result, it is possible to manufacture a glass preform for an optical fiber that is less contaminated with foreign matter.

It is a perspective view at the time of door opening of the reaction container for glass fine particle deposits manufacture concerning the present invention. It is a perspective view at the time of the door closing of the reaction container for glass fine particle deposits manufacture shown in FIG. It is sectional drawing of a flame | frame and a mating surface at the time of a door closing. (A) is sectional drawing when the clamp member is not clamped, (b) is a sectional view when the clamp member is clamped. (A) is sectional drawing at the time of opening surface opening in the conventional reaction container for glass fine particle deposit body manufacture, (b) is sectional drawing at the time of opening surface sealing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view when a reaction container for producing a glass fine particle deposit according to the present invention is opened, and FIG. 2 is a perspective view when the reaction container for producing a glass fine particle deposit shown in FIG. 1 is closed.
A reaction vessel 100 for producing a glass particulate deposit (hereinafter simply referred to as “reaction vessel”) 100 has a metal furnace body 11 formed in, for example, a rectangular parallelepiped shape and having a heat-resistant temperature of 200 to 300 ° C. An opening 17 for attaching the starting rod 15 and cleaning the inside is provided on one side (opening surface 13) of the person side. A square frame-shaped mating surface 19 that is a mating surface with the door 23 is formed on the opening surface 13 around the opening 17. A door 23 is rotatably attached to the furnace body 11 via a hinge 21, and the door 23 covers the opening surface 13 and seals the opening 17. That is, the mating surface 19 around the opening 17 and the mating surface 25 of the door 23 are in an airtight state. The inner surfaces of the furnace body 11 and the door 23 are covered with a metal partition wall 27.

  The reaction vessel 100 has an air supply port (not shown) for supplying gas, an exhaust port 29 for discharging gas in the furnace body 11, and a start for depositing a target (porous base material) 33 in the furnace body 11. The rod 15, the burner 35 that is disposed on the opposite side of the exhaust port 29 across the target 33 and deposits the generated fine glass particles on the starting rod 15, and the quartz that allows the inside of the reaction vessel to be observed with the door 23 closed. An observation window 37 made of glass.

The burner 35 is supplied to the starting rod 15 with silicon tetrachloride (SiCl ₄ ) as a raw material gas, hydrogen gas (H ₂ ) as a fuel gas, oxygen gas (O ₂ ) as an auxiliary fuel gas, and inert gas (N ₂ ). Is used to generate glass fine particles together with the flame 39 by a hydrolysis reaction or a thermal oxidation reaction and deposit them on the starting rod 15. In addition, although FIG. 1 has shown the example with one burner, it does not specifically limit to one burner.

  A belt-like packing 41 as a first sealing material is fixed to the mating surface 19 of the furnace body 11 having a square frame shape around the opening of the furnace body 11. The packing 41 is formed in a square frame shape that is substantially the same shape as the outer frame of the mating surface 25 of the door 23, and is held on the mating surface 19 of the furnace body 11 with an adhesive, a locking structure, or a fixing screw. In this embodiment, it is fixed with a fixing screw 42 (see FIG. 3). As the packing 41, a material having heat resistance of 200 ° C. or higher, for example, a fluororesin such as Teflon (registered trademark) can be suitably used. When the door 23 is closed, the opening 17 of the furnace body 11 is sealed with high airtightness with the packing 41 sandwiched between the mating surfaces 19 and 25.

FIG. 3 is a cross-sectional view of the frame and the mating surface when the door is closed.
As shown in FIG. 3, when the door 23 is closed, the end portions 19 a and 25 a are exposed at the mating surfaces 19 and 25 around the opening 17 in close contact with the packing 41. The end portions 19 a and 25 a of the mating surfaces 19 and 25 are exposed along the outer peripheral portions of the four sides of the rectangular door 23. The reaction vessel 100 is attached with a frame 49 in which a second sealing material, which will be described later, is installed so as to cover the end portions 19a and 25a, and a plurality of doors fixed in a closed state as shown in FIG. A clamp member 47 is attached.

  The clamp member 47 has a U-shaped cross section for pressing the frame 49 against the mating surfaces 19 and 25. The frame 49 is divided into four pieces along the four sides of the end portions 19a and 25a. The frame 49 may have a flat plate shape, or may be formed of a long material having a U-shaped cross section that sandwiches the furnace body 11 and the door 23 inside as shown in the illustrated example. An L-shaped angle member 51 shown in FIG. 3 is fixed to the outer periphery of the door 23, and an L-shaped angle member 53 is fixed to the outer periphery of the mating surface 19 of the furnace body 11.

4A is a cross-sectional view when the clamp member is not clamped, and FIG. 4B is a cross-sectional view when the clamp member is clamped.
As shown in FIG. 4A, the clamp member 47 is a mechanical clamp including an output rod 63, a toggle mechanism 65, and a lever handle 61, and is output via the lever handle 61 driven manually. The rod 63 is driven to clamp the frame 49 to the door 23 and the furnace body 11 side.

  A slope member 67 is fixed to one side 51 a of the angle member 51 provided on the outer peripheral edge of the door 23, and the slope member 67 has an inclined surface 67 a that gradually decreases toward the other side 51 b of the angle member 51. doing.

  As shown in FIG. 4B, the clamp member 47 is rotated around the support pin 57 as a rotation center, and the lever handle is at a position (clamp position) between which the angle members 51 and 53 are sandwiched inside the frame 49. When 61 is rotated, the output rod 63 protrudes through the toggle mechanism 65, and the tip of the output rod 63 is pressed against the inclined surface 67 a of the slope member 67. When the output rod 63 presses the inclined surface 67a, a reaction force urged in the right direction in FIG. 4 acts on the clamp member 47 via the output rod 63, and the frame 49 aligns the inner surface 49a with the mating surfaces 19, It is urged | biased in the direction which approaches the edge parts 19a and 25a of 25.

  The toggle mechanism 65 is in a clamped state by the lever handle 61 being tilted in the clamping direction and pressing the output rod 63. In the clamped state, unless the lever handle 61 is operated, the output rod 63 is not retracted to the release position side due to an external force. An adjustment member 71 that can adjust the protruding length is screwed to the tip of the output rod 63. By adjusting the rotation of the adjustment member 71, the tip position of the output rod 63 can be changed to change the clamping force of the output rod 63 against the inclined surface 67a.

  When the clamp member 47 is in the clamping position, the inner surface 49a of the frame 49 becomes a surface perpendicular to the mating surfaces 19 and 25. A belt-like gasket 73, which is a heat-resistant second sealing material, is fixed to the inner surface 49a with an adhesive, a locking structure, or a fixing screw. As shown in FIG. 4B, the gasket 73 includes one side 51a, 53a (see FIG. 3) of the angle members 51, 53, the partition wall 27, each end surface of the packing 41 (the mating surfaces 19, 25 of these members). The surface is perpendicular to the surface 75). That is, the gasket 73 is pressed against the end portions 19 a and 25 a of the mating surfaces 19 and 25. The gasket 73 covers the end portions 19a and 25a of the mating surfaces 19 and 25 so as to cross in the vertical direction of FIG. 4B. In FIG. 4A, an extended virtual surface of the end surface 75 is indicated by a two-dot chain line.

  As the gasket 73, a silicone rubber sponge can be suitably used. Silicone rubber sponge is a synthetic resin mainly composed of a silicon compound (polymer silicone, etc.), and is excellent in heat resistance, chemical resistance, self-lubricating property, wear resistance, heat insulating property, and impact resilience. For example, in the case of a low-foamed silicon rubber sponge having a foaming ratio of about 4 times, the silicon rubber sponge can be used up to about 200 ° C. depending on the degree of compression. The low foam silicon rubber sponge is a closed cell and has a hardness of about 15 degrees. The gasket 73 made of silicon rubber sponge can maintain the sealed structure by absorbing the displacement of the mating surfaces 19 and 25 due to thermal expansion by the cushioning property even at a high temperature of about 200 ° C.

Next, the operation of the reaction vessel 100 having the above configuration will be described.
When the door 23 is closed, the reaction vessel 100 is brought into close contact with the mating surfaces 19 and 25 with the packing 41 interposed therebetween. When the clamp member 47 is rotated to the clamp position around the support pin 57, the frame 49 is disposed so as to cover the angle members 51 and 53.

  The peripheral edge portion of the opening 17 formed in the furnace body 11 and the peripheral edge portion of the door 23 are overlapped in a closed state, and the end portions 19a and 25a of the mating surfaces 19 and 25 of the peripheral edge portions are gaskets 73 which are second sealing materials. It is blocked by. The gasket 73 is disposed on the inner surface of the frame 49 installed so as to cover the mating surfaces 19 and 25, and a clamp member 47 is further provided on the outer side of the gasket 73 to fix it in a closed state.

  In this state, when the lever handle 61 of each clamp member 47 is operated in the clamping direction, the output rod 63 protrudes through the toggle mechanism 65 and presses the slope member 67. As a result, the packing 41 is sandwiched between the mating surfaces 19 and 25, the gap is closed in a highly airtight manner, and the previous gap closing (airtight sealing) is performed.

  By using the packing 41 having a heat-resistant temperature of 200 ° C. or higher for the mating surfaces 19 and 25, the gap in the previous stage can be closed, and the outside temperature can be lowered due to the heat shielding and heat insulating effects. In general, a material having a heat resistance of 200 ° C. or higher has few materials that can be applied as a packing because it is not flexible, has low corrosion resistance, or becomes a contamination source itself. Although there are packings with a high heat-resistant temperature, it is not practical in terms of cost. In contrast, thick Teflon (registered trademark) is not very flexible, but it can withstand temperatures of 200 ° C. or higher, so it can be used as packing 41, and its thermal conductivity is low, so it is effective in reducing the temperature of the outer peripheral surface. It becomes.

  Next, when all the clamp members 47 are clamped, the clamp members 47 have a U-shaped cross section, and the clamp member 47 fixes the furnace body end portion and the door end portion by sandwiching and clamping. . In addition, by tightening with the clamp member 47, the mating surfaces 19 and 25 exposed on the peripheral edge of the opening 17 are pressed against the gasket 73 disposed on the inner surface of the frame 49, and are sealed and closed. .

  Thereby, the clearance gap between the furnace body 11 and the door 23 is block | closed with a multistage structure, and airtightness improves. Since the heat insulation effect is obtained by the packing 41 at the front gap closing portion, the rear gap closing portion is at a lower temperature than the front gap closing portion. Accordingly, since the gap closing portion at the rear stage can sufficiently close the gap under relatively low temperature conditions, the options for the sealing material can be expanded, and contamination with foreign matter into the furnace body 11 is reliably prevented. Become. Silicone rubber sponge has a sufficient cushioning property despite its heat resistant temperature of about 200 ° C., and the gap can be completely closed by adopting a structure that presses against the outer peripheral surface of the door.

  Therefore, according to the reaction vessel 100 configured as described above, the packing 41 is provided on the mating surfaces 19 and 25 of the furnace body 11 and the door 23, and the clamp member 47 surrounding the end portions 19 a and 25 a of the mating surfaces 19 and 25 is attached. Since the heat-resistant gasket 73 is provided on the inner surface 49a perpendicular to the mating surfaces 19 and 25 of the clamp member 47, the sealing performance of the furnace body 11 and the door 23 can be improved, and foreign matter can be prevented from being mixed. As a result, it is possible to manufacture a glass preform for an optical fiber that is less contaminated with foreign matter.

  A reaction vessel having the same structure as that described above was actually manufactured, and the degree of contamination of foreign matter was compared with a reaction vessel having a conventional structure in which the packing 41 and the gasket 73 are not provided. As a result, it was confirmed that the reaction container with the conventional structure had 3000 foreign matter floating amounts with a particle diameter of about 0.5 μm, whereas the reaction container according to the invention manufactured with the above configuration had 1000 or less. did it.

11 furnace body 13 opening surface 19, 25 mating surface 19a, 25a end of mating surface 23 door 33 target 35 burner 39 oxyhydrogen flame 41 packing (first sealing material)
47 Clamp member 49 Frame 49a Inner surface perpendicular to the mating surface of the clamp member 73 Gasket (second sealing material)
100 Reaction vessel for producing glass particulate deposits

Claims (2)

A furnace body having a burner for spraying and depositing glass fine particles on a target by an oxyhydrogen flame; and a door that covers an operator-side opening surface of the furnace body; a first surface on a mating surface of the furnace body and the door; A reaction vessel for producing a glass particulate deposit provided with a sealing material of
A second sealing material having heat resistance attached to the end portion so as to cover the end portion of the mating surface from the outside on the outer periphery perpendicular to the mating surface ,
The second sealing material is disposed on the inner surface of the frame installed so as to cover the end of the mating surface from the outside,
A plurality of U-shaped cross sections for holding the door in a closed state, sandwiching the end of the furnace body and the end of the door, and pressing the frame against the mating surface, outside the frame A reaction container for producing a glass particulate deposit, wherein a clamp member is provided . A reaction vessel for producing a glass particulate deposit according to claim 1,
The second sealing material is a silicon rubber sponge, a reaction container for producing a fine glass particle deposit.

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